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How to Navigate the<br />

Technical Sessions<br />

There are four primary resources to help you<br />

understand and navigate the Technical Sessions:<br />

This Technical Session listing, which provides the<br />

most detailed information. The listing is presented<br />

chronologically by day/time, showing each session<br />

and the papers/abstracts/authors within each<br />

session.<br />

The Author and Session indices provide<br />

cross-reference assistance (pages 468-505).<br />

The floor plans on pages 42 and 43 show you where<br />

technical session tracks are located.<br />

Quickest Way to Find Your Own Session<br />

Use the Author Index (page 468) — the session code<br />

for your presentation will be shown along with the room<br />

location. You can also refer to the full session listing for<br />

the room location of your session.<br />

The Session Codes<br />

TA01<br />

The day of<br />

the week<br />

Time Blocks<br />

<strong>Sunday</strong> - Tuesday<br />

A — 8:00am - 9:30am<br />

B — 11:00am - 12:30pm<br />

C — 1:30pm - 3:00pm<br />

D — 4:30pm - 6:00pm<br />

Wednesday<br />

A — 8:00am - 9:30am<br />

B — 11:00am - 12:30pm<br />

C — 1:30pm - 3:00pm<br />

D — 3:20pm - 4:50pm<br />

Room number. Room locations are<br />

also indicated in the listing for each<br />

session.<br />

Time Block. Matches the time<br />

blocks shown in the Program<br />

Schedule.<br />

Room Locations /Tracks<br />

All tracks and technical sessions will be held in the<br />

Phoenix Convention Center, and Hyatt Hotel.<br />

Room numbers are shown on the Track Schedule and<br />

in the technical session listing.<br />

55<br />

<strong>Sunday</strong>, 8:00am - 9:30am<br />

■ SA01<br />

T ECHNICAL S ESSIONS<br />

01- West 101- CC<br />

GRASP and Tabu Search<br />

Contributed Session<br />

Chair: Celso Ribeiro, Universidade Federal Fluminense, Institute of<br />

Computing, Niteroi, RJ, 22410240, Brazil, celso@ic.uff.br<br />

1 - An Improved GRASP with Path Relinking for<br />

Commercial Districting<br />

Roger Rios, Professor, Universidad Autonoma de Nuevo Leon,<br />

Graduate Program in Systems Engineering, AP 111-F, Cd.<br />

Universitaria, San Nicolas de los Garza, NL, 66450, Mexico,<br />

roger@yalma.fime.uanl.mx, Hugo Escalante<br />

A commercial districting problem seeking to minimize territory dispersion under<br />

connectivity and multiple balancing constraints is addressed. A GRASP with path<br />

relinking (PR) is proposed. Both static and dynamic PR strategies are developed<br />

and assessed within a GRASP framework. Empirical work shows the effectiveness<br />

of the proposed method outperforming the best existing method in terms of<br />

solution quality.<br />

2 - A Heuristic for a Real-world VRP Arising in a Bottled-beverage<br />

Distribution Company<br />

Andrés Castrillón-Escobar, Student, UANL, Salvador Novo 105,<br />

Monterrey, Me, 64630, Mexico, cuatex1@hotmail.com,<br />

Roger Rios, J. Fabián Lopèz-Perèz<br />

A real-world problem arising from the bottled-beverage distribution industry is<br />

addressed. The problem is modeled as a multi-depot pick-up and delivery<br />

capacitated VRP with additional side constraints such as time windows, nonhomogeneous<br />

fleet, split delivery, and dock capacity, among others. To solve this<br />

problem, a GRASP is proposed. Empirical evidence on real-world very large<br />

instance is presented showing the proposed procedure improves current practice<br />

in terms of solution quality.<br />

3 - Redundancy Allocation Problem of Complex System using<br />

Metaheuristics: A Computational Study<br />

Jae-Hwan Kim, Professor, Korea Maritime University, Yeongdo-Gu<br />

Dongsam-Dong, Busan, Korea, Republic of, jhkim@hhu.ac.kr,<br />

Kil-Woong Jang<br />

Redundancy allocation problem (RAP) is to select redundancy levels at each<br />

subsystem in order to maximize the system reliability under several resource<br />

constraints(e.g., cost). The RAP is a well-known NP-hard combinatorial<br />

optimization problem. We present some metaheuristics (tabu search, etc.) for its<br />

solution. A computational study for the composed test problems is also analyzed.<br />

4 - Probabilistic Stopping Rules for GRASP Heuristics<br />

Celso Ribeiro, Universidade Federal Fluminense, Institute of<br />

Computing, Niteroi, RJ, 22410240, Brazil, celso@ic.uff.br,<br />

Reinaldo Castro Souza, Isabel Rosseti<br />

A drawback of most metaheuristics is the absence of effective stopping rules. We<br />

show experimentally that solution values obtained by GRASP fit a truncated<br />

Normal distribution and use this approximation to estimate the number of<br />

iterations needed to improve the best known solution. This estimation is used to<br />

implement stopping rules based on the trade-off between solution quality and<br />

computation time. This strategy is validated by results obtained for some GRASP<br />

heuristics.<br />

5 - Evaluation of Run-length Distribution for CUSUM Charts under<br />

Gamma Distributions<br />

Wenpo Huang, University of Macau, Faculty of Business<br />

Administration, Block1, B408, FBA, Taipa, Macau, China,<br />

wenpohuang@umac.mo, Lianjie Shu, Wei Jiang, Kwok Tsui<br />

Numerical evaluation of run-length distributions of CUSUM charts under normal<br />

distributions has received considerable attention. However, accurate<br />

approximation of run-length distributions under non-normal or skewed<br />

distributions is challenging but has been previously overlooked. This paper<br />

provides a fast and accurate algorithm based on the piecewise collocation method<br />

for computing the run-length distribution of CUSUM charts under skewed<br />

distributions such as gamma distributions. It is shown that the piecewise<br />

collocation method can provide a more robust approximation of the run-length<br />

distribution than other existing methods such as the Gaussian quadrature based<br />

approach, especially when the process distribution is heavily skewed. Some<br />

computational aspects including alternative formulation based on matrix<br />

decomposition and geometric approximation of run-length distribution are<br />

discussed. Design guidelines of such CUSUM chart are also provided.


SA02<br />

■ SA02<br />

02- West 102 A- CC<br />

Decision Analysis Applications in the Energy Industry<br />

Sponsor: Decision Analysis<br />

Sponsored Session<br />

Chair: Mazen Skaf, Partner & Managing Director, Strategic Decisions<br />

Group, 745 Emerson St, Palo Alto, CA, 94301, United States of<br />

America, MSkaf@sdg.com<br />

1 - A Decision Quality Approach to Natural Gas Resource<br />

Uncertainty<br />

Robert Stibolt, Managing Director, Galway Group, L.P.,<br />

3050 Post Oak Blvd., Suite 1300, Houston, TX, 77056,<br />

United States of America, rstibolt@galwaygroup.com, Mazen Skaf<br />

The shale gas revolution started in North America has completely changed the<br />

dynamic of world natural gas markets. Implications are far-reaching, exciting, but<br />

also highly uncertain. For example, the shape of long-run supply curves depend<br />

on technology, geology, and geopolitics. This paper addresses these questions<br />

within a framework that embraces uncertainty while eschewing the illusion of<br />

precise prediction — a key to developing natural gas strategies that are robust.<br />

2 - Hydrocarbon Resource Allocation Strategy for Industry<br />

Development in an Energy-rich Nation<br />

Mazen Skaf, Partner & Managing Director, Strategic Decisions<br />

Group, 745 Emerson St., Palo Alto, CA, 94301,<br />

United States of America, MSkaf@sdg.com, Thomas Seyller<br />

We present a DA-based process and system for optimizing the allocation of<br />

supplies of a hydrocarbon resource across proposed industrial projects taking into<br />

account: i) uncertainty in future supply and demand, ii) various economic, social,<br />

and environmental value measures, and iii) existing commitments for current<br />

domestic uses and industries. The value-focused approach resulted in a paradigm<br />

shift in the industrial development strategy as well as in the future focus of E&P<br />

activities.<br />

3 - Solar Value Chain Decision Analysis in Oil and Gas Rich<br />

Countries<br />

Thomas Seyller, Sr. Engagement Manager, Strategic Decisions<br />

Group, 745 Emerson St., Palo Alto, CA, 94301,<br />

United States of America, tseyller@sdg.com, Dan Cornew<br />

We will explore how decision analysis can help oil and gas rich countries develop<br />

strategies around solar energy that maximize the total benefit to the nation –<br />

including economic value and costs, social benefits such as job creation, and<br />

environmental impacts. Strategies cover a wide range of possible incentives and<br />

mandates throughout the solar value chain, from manufacturing to deployment.<br />

■ SA03<br />

03- West 102 B- CC<br />

Risk and Uncertainty in Public Policy and Defense<br />

Sponsor: Decision Analysis<br />

Sponsored Session<br />

Chair: Jay Simon, Naval Postgraduate School, Defense Resources<br />

Management Institute, 699 Dyer Rd, Monterey, CA, 93943,<br />

United States of America, jrsimon@nps.edu<br />

1 - Uncertainty Model for Rapid Updating of Target Positions<br />

Eva Regnier, Naval Postgraduate School, 699 Dyer Road,<br />

Monterey, CA, 93943, United States of America,<br />

eregnier@nps.edu, Dashi Singham<br />

In many security contexts, forces must allocate their assets based on incomplete<br />

information about targets’ positions. They frequently receive human intelligence<br />

describing past or future events related to target locations. We present an<br />

uncertainty model that allows for rapid updating, conditioning on past or future<br />

events.<br />

2 - Ranking FDA Risks: The Medical Devices Case<br />

Robin Keller, University of California-Irvine, Irvine, CA,<br />

United States of America, lrkeller@uci.edu, Yitong Wang<br />

This talk focuses on a medical devices case study. Keller served as a decision<br />

analyst on the committee charged with suggesting how the FDA can compare<br />

risks across product categories (foods, cosmetics, drugs, etc.). The NRC book<br />

proposed a multiple objective decision analytic approach to ranking risks: “A Risk-<br />

Characterization Framework for Decision-Making at the Food and Drug<br />

Administration” is at http://dels.nas.edu/Report/Risk-Characterization-<br />

Framework-Decision/13156.<br />

INFORMS Phoenix – 2012<br />

56<br />

3 - Probability Segmenting: Managing Uncertainty in Military Drafts<br />

Jay Simon, Naval Postgraduate School, Defense Resources<br />

Management Institute, 699 Dyer Rd, Monterey, CA, 93943,<br />

United States of America, jrsimon@nps.edu, Jonathan Lipow<br />

When a nation chooses to enact a draft, this presents an interesting decision<br />

problem for those individuals eligible to be drafted: they can take actions which,<br />

at some cost, will reduce the probability of being selected. It is in society’s best<br />

interest to minimize these costly actions. We discuss “probability segmenting,” the<br />

idea of randomly assigning different probabilities to different individuals, as a<br />

possible method for improving the outcome at a societal level.<br />

■ SA04<br />

04- West 102 C- CC<br />

Advances in Decision Analysis<br />

Contributed Session<br />

Chair: Steven Kimbrough, Professor, University of Pennsylvania,<br />

3730 Walnut St., Philadelphia, PA, 19104, United States of America,<br />

kimbrough@wharton.upenn.edu<br />

1 - Extending the Multiscale Decision-making Model: From Two to<br />

Many Decision Alternatives<br />

Swathi Sudhaakar, Graduate Student, Virginia Tech, 116 Durham<br />

Hall, MC 0118, Blacksburg, VA, 24061, United States of America,<br />

swathips@vt.edu, Christian Wernz<br />

We generalize the multiscale decision making model by extending the agents’<br />

action space from two to N decision alternatives. Multiscale decision theory<br />

(MSDT) models the interaction and decision interdependencies of agents in large<br />

enterprise systems. With our results, MSDT can now be applied to a wider range<br />

of applications and provides organizational and system designers with insights on<br />

how the number of decision alternatives affects agents’ decision processes.<br />

2 - On the Axiomatization of the Satiation and Habit Formation<br />

Utility Models<br />

Ying He, PhD Candidate, University of Texas at Austin,<br />

Department Information, Risk & Operational Mg, 1 University<br />

Station, B6000, Austin, TX, 78712, United States of America,<br />

ying.he08irom@utexas.edu, James Dyer, John Butler<br />

We propose a preference condition called shifted difference independence to<br />

axiomatize a general habit formation and satiation (GHS) model. Since the GHS<br />

model can be reduced to either a general satiation model (GSa) or a general habit<br />

formation model (GHa), our theory also provides approaches to axiomatize both<br />

the GSa and the GHa model. By adding extra preference conditions, we<br />

axiomatize a GHS model with a linear habit function and a linear satiation<br />

function.<br />

3 - Strategic Experimentation under Exclusivity<br />

Stefan Rampertshammer, Duke University, Fuqua School of<br />

Business, 100 Fuqua Drive, Durham, NC, 27516,<br />

United States of America, Stefan.Rampertshammer@duke.edu<br />

We study a model of strategic experimentation with exponential bandits in which<br />

we attach a prize and a level of exclusivity to the first success. We determine the<br />

socially optimal policy, examine equilibrium behavior, and show that the efficient<br />

outcome can be recovered in dominant strategy through a combination of<br />

exclusivity and prizes.<br />

4 - Solution Pluralism<br />

Steven Kimbrough, Professor, University of Pennsylvania, 3730<br />

Walnut St., Philadelphia, PA, 19104, United States of America,<br />

kimbrough@wharton.upenn.edu, Frederic Murphy<br />

Solution pluralism involves generating a plurality of optimal and near-optimal<br />

solutions for use by stakeholders. Modern heuristics and ever-advancing<br />

computational powers make solution pluralism a practicable approach to explore<br />

for near optimal solutions as a form of sensitivity analysis and multiple candidate<br />

solutions when the problem has multiple objectives. We discuss the concept and<br />

principles of solution pluralism and illustrate it with a real world application to<br />

electoral districting.


■ SA05<br />

05- West 103 A- CC<br />

Journal of Quality Technology Invited Papers<br />

Sponsor: Quality, Statistics and Reliability<br />

Sponsored Session<br />

Chair: Daniel Apley, NorthWestern University, 2145 Sheridan Road,<br />

Evanston, IL, 60208, United States of America,<br />

apley@northwestern.edu<br />

1 - Bayesian Modeling and Optimization of Functional Responses<br />

Affected by Noise Factors<br />

Enrique del Castillo, Distinguished Professor, Department of<br />

Industrial & Manufacturing Engineering & Department of<br />

Statistics, Penn State University, University Park, PA, United States<br />

of America, exd13@psu.edu, Bianca M. Colosimo,<br />

Hussam Alshraideh<br />

We present a Bayesian predictive modeling approach for functional response<br />

systems. The goal is to optimize the shape, or profile, of the functional response<br />

under a robust parameter design scenario in which there are controllable and<br />

noise factors. The method is illustrated with real examples and model building<br />

and diagnostics aspects of the assumed mixed effects model are discussed.<br />

Alternative modeling strategies beyond those in the JQT paper (2012, 44(2)) will<br />

be presented.<br />

2 - Robust Leak Tests for Transmission Systems using Nonlinear<br />

Mixed-Effect Models<br />

Kamran Paynabar, University of Michigan, Ann Arbor, MI,<br />

United States of America, kamip@umich.edu, Judy Jin,<br />

John Agapiou, Paula Deeds<br />

Leakage of the transmission fluid or oil in powertrain systems can cause engine<br />

overheating and/or permanent damages. The inspection results of the amount of<br />

leakage at given testing times are sensitive to the tested part’s temperature, which<br />

varies from part to part but was not previously incorporated in the leak testing<br />

systems. The objective of this paper is to develop a robust leak testing system<br />

using nonlinear mixed-effect models, which is insensitive to the part temperature<br />

variations.<br />

3 - A Variable-Selection-based Multivariate EWMA Chart for<br />

Process Monitoring and Diagnosis<br />

Kaibo Wang, Associate Professor, Tsinghua University,<br />

Department of Industrial Engineering, Beijing, China,<br />

kbwang@tsinghua.edu.cn, Wei Jiang, Fugee Tsung<br />

Fault detection and root cause identification are both important tasks in<br />

Multivariate Statistical Process Control. This paper proposes a Variable-Selectionbased<br />

MEWMA chart. The new chart first locates potentially out-of-control<br />

variables via variable selection, and then deploys such information in the<br />

monitoring statistics with the reduction in dimensionality providing increased<br />

sensitivity to out-of-control conditions. Its performance is studied via numerical<br />

simulations and real examples.<br />

■ SA06<br />

06- West 103 B- CC<br />

Efficient Learning in Stochastic Optimization<br />

Sponsor: Simulation<br />

Sponsored Session<br />

Chair: Ilya Ryzhov, University of Maryland, 4322 Van Munching Hall,<br />

College Park, MD, 21044, United States of America,<br />

iryzhov@rhsmith.umd.edu<br />

1 - Dynamic Pricing under a General Parametric Choice Model<br />

Paat Rusmevichientong, Associate Professor, University of<br />

Southern California, Marshall School of Business,<br />

rusmevic@marshall.usc.edu, Josef Broder<br />

We consider a stylized dynamic pricing model in which a monopolist prices a<br />

product to a sequence of customers, who independently make purchasing<br />

decisions based on the price offered according to a general parametric choice<br />

model. The parameters of the model are unknown to th<br />

INFORMS Phoenix – 2012<br />

57<br />

SA07<br />

e seller, whose objective is to determine a pricing policy that minimizes the regret.<br />

We characterize the regret profile for this problem.<br />

2 - Kernelized Approximate Linear Programming<br />

Vivek Farias, Massachusetts Institute of Technology,<br />

77 Massachusetts Avenue, Cambridge, MA, United States of<br />

America, vivekf@mit.edu, Ciamac Moallemi, Nikhil Bhat<br />

We present a practical, non-parametric ADP algorithm that enjoys graceful,<br />

dimension-independent approximation and sample complexity guarantees by<br />

‘kernelizing’ a recent mathematical program for ADP (the ‘smoothed’<br />

approximate LP). A computational study on a controlled queueing network<br />

shows that our procedure is competitive with state of the art parametric ADP<br />

approaches that employ carefully tailored approximation architectures.<br />

3 - Sequential Filtering of Glaucoma Progression<br />

Jonathan Helm, Assistant Professor, Indiana University, Kelley<br />

School of Business, ODT, 1309 East Tenth Street, Bloomington, IN,<br />

47405, United States of America, jhelm@umich.edu, Mariel<br />

Lavieri, Mark Van Oyen, Joshua Stein, MD<br />

We develop novel filtering algorithms for monitoring the disease progression of<br />

glaucoma patients. The models are validated using patient data from two multicenter<br />

clinical trials.<br />

4 - Ranking and Selection with Unknown Correlation Structures<br />

Huashuai Qu, University of Maryland, College Park, MD,<br />

United States of America, huashuai@math.umd.edu, Ilya Ryzhov,<br />

Michael Fu<br />

We create the first computationally tractable Bayesian statistical model for<br />

learning unknown correlations among alternatives in fully sequential ranking and<br />

selection. We can learn the unknown values and unknown correlations<br />

simultaneously with the model. A Bayesian procedure is derived to allocate<br />

simulations based on the value of information. We test the model and algorithm<br />

in a simulation study motivated by the problem of optimal wind farm placement,<br />

and obtain encouraging empirical results.<br />

■ SA07<br />

07- West 104 A- CC<br />

Joint Session DM/HAS: Data Mining in Health Care<br />

Sponsor: Data Mining & Health Applications Society<br />

Sponsored Session<br />

Chair: Shengfan Zhang, Assistant Professor, University of Arkansas,<br />

4207 Bell Engineering Center, Fayetteville, AR, 72701,<br />

United States of America, shengfan@mail.uark.edu<br />

1 - Analyzing Human Microbiome Data<br />

Paul Brooks, Assistant Professor, Department of Statistical Sciences<br />

and Operations Research, Virginia Commonwealth University,<br />

P.O. Box 843083, Richmond, VA, 23284, United States of America,<br />

jpbrooks@vcu.edu, Microbiome Consortium<br />

The human microbiome is the community of microbes that populate habitats on<br />

and around various body sites. Advances in high-throughput sequencing facilitate<br />

investigations into the impact of the microbiome on physiology and disease.<br />

Microbiome data presents unique challenges for analysis. In this talk, we present<br />

methods for analysis that seek to address some of these challenges.<br />

2 - Outcome and State Transition Modeling for Adaptive<br />

Interdisciplinary Pain Management<br />

Aera LeBoulluec, PhD Student/GRA, University of Texas-<br />

Arlington, 2205 Hunter Place Lane, Arlington, TX, 76006,<br />

United States of America, aera.leboulluec@mavs.uta.edu, Li Zeng,<br />

Victoria Chen<br />

In this research, we seek adaptive treatment strategies for interdisciplinary pain<br />

management using data from the Eugene McDermott Center for Pain<br />

Management at the University of Texas Southwestern Medical Center at Dallas.<br />

An adaptive dynamic programming approach is formulated to improve current<br />

and future pain outcomes. Outcome and state transition modeling handle the<br />

problem of endogeneity via an inverse probability of treatment weighting<br />

approach.<br />

3 - Machine Learning with Operational Costs<br />

Cynthia Rudin, Assistant Professor, Massachusetts Institute of<br />

Technology, 77 Massachusetts Avenue, Cambridge, MA,<br />

United States of America, rudin@mit.edu, Theja Tulabandhula<br />

We aim to merge theway estimation algorithms are designed with how they are<br />

used for a subsequent task. We consider the operational cost of carrying out a<br />

policy, based on a predictive model. The operational cost becomes a regularization<br />

term in the learning algorithm’s objective, allowing either an optimistic or<br />

pessimistic view of possible costs. Limiting the operational cost reduces the<br />

hypothesis space, and can thus improve generalization. We bound the complexity<br />

of such hypothesis spaces.


SA08<br />

4 - Predictive Modeling of Glycosylation Modulation Dynamics in<br />

Cardiac Electrical Signaling<br />

Hui Yang, Assistant Professor, University of South Florida,<br />

Tampa, FL, 33620, United States of America, huiyang@usf.edu<br />

The cardiac action potential is produced by the orchestrated functions of ion<br />

channel dynamics. This investigation is aimed at modeling the variations of<br />

cardiac electrical signaling due to remodeling of a K+ channels. This multi-scale<br />

modeling investigation reveals novel mechanisms of hERG channel modulation<br />

by regulated glycosylation that also impact cardiac myocyte and tissue functions.<br />

It can potentially lead to new pharmaceutical treatments and drug designs for<br />

cardiac arrhythmia.<br />

■ SA08<br />

08- West 104 B- CC<br />

Inventory Management for Global Health<br />

Sponsor: Public Programs, Service and Needs<br />

Sponsored Session<br />

Chair: Jeremie Gallien, London Business School, Regent’s Park,<br />

London, NW14SA, United Kingdom, jgallien@london.edu<br />

1 - Improving the Public Distribution of Essential Medicines in<br />

Sub-Saharan Africa: The Case of Zambia<br />

Zachary Leung, Massachusetts Institute of Technology,<br />

77 Massachusetts Ave., Cambridge, MA, United States of America,<br />

zacleung@mit.edu, Jeremie Gallien, Prashant Yadav<br />

Despite remarkable and successful improvements efforts by the government and<br />

its partners, the current public distribution system of essential medical drugs in<br />

Zambia still results in low availability to patients relative to private sector<br />

standards. We present an alternative design involving mobile devices and<br />

optimization and evaluate this proposal via a simulation model built with field<br />

data. Our results suggest that this proposal would improve drug availability and<br />

reduce inventory costs.<br />

2 - Malaria Treatment Distribution in Developing World Health<br />

Systems and Application to Malawi<br />

Hoda Parvin, Research Analyst, CNA, 4825 Mark Center Dr.,<br />

Alexandria, VA, 22311, United States of America,<br />

parvinh@cna.org, Shervin AhmadBeygi, Mark Van Oyen,<br />

Peter Larson, Jonathan Helm<br />

We present stochastic models to address malaria treatment distribution in<br />

developing world under demand uncertainty. We first analyze a two-stage<br />

stochastic programming approach to make aggregate-level nation-wide decisions.<br />

We then present a Markov decision model to develop operational-level<br />

transshipment strategies within a cluster of clinics.<br />

3 - Public Health Impact of the Global Fund’s Performance-based<br />

Financing Process: A Queueing Analysis<br />

Iva Rashkova, London Business School, London, United Kingdom,<br />

irashkova.phd2009@london.edu, Jeremie Gallien, Prashant Yadav<br />

The Global Fund is the largest financier of programs against HIV, Malaria and<br />

Tuberculosis. We study its disbursement process through (i) an econometric<br />

analysis of disbursement and procurement data between 2003 and 2012; and (ii)<br />

a queueing model predicting national stock levels of medicines. This model<br />

quantifies the impact of the current process on central drug availability in 48<br />

African countries and potential interventions that include bridge financing and an<br />

international buffer stock.<br />

4 - Inventory Management in Humanitarian Supply Chains:<br />

The Role of Schedules and Uncertainty in Funding<br />

Karthik V. Natarajan, University of North Carolina, Chapel Hill,<br />

NC, United States of America, karthik_natarajan@unc.edu,<br />

Jayashankar M. Swaminathan<br />

Motivated by the ready-to-use therapeutic food (RUTF) supply chain in Africa, we<br />

study the problem of managing inventory of a nutritional product in the presence<br />

of variable funding constraints. We derive the structure of the optimal inventory<br />

and allocation policy and computationally analyze the impact of different funding<br />

schedules on the operating costs andwaiting times in the system.<br />

INFORMS Phoenix – 2012<br />

58<br />

■ SA09<br />

09- West 105 A- CC<br />

Evolutionary Multi-Criterion Optimization - I<br />

Sponsor: Multiple Criteria Decision Making<br />

Sponsored Session<br />

Chair: Kalyanmoy Deb, Professor, Indian Institute of Technology<br />

Kanpur, Department of Mechanical Engineering, Kanpur, UP, 208016,<br />

India, deb@iitk.ac.in<br />

1 - A Decentralized Bicriteria Timeshare Exchange Algorithm<br />

Bahriye Cesaret, PhD Student, Jindal School of Management,<br />

University of Texas at Dallas, 800 West Campbell Road,<br />

Richardson, TX, 75080, United States of America,<br />

bahriye.cesaret@utdallas.edu, Milind Dawande,<br />

Tharanga Rajapakshe<br />

Timeshare Exchange refers to the trading of vacation timeshare weeks among<br />

owners, so that they can interchange their respective vacation homes and thereby<br />

experience new destinations. We consider two objectives to capture the notions of<br />

“efficiency” and “fairness” in an exchange solution. Our main contributions<br />

include (i) a structural analysis of the resulting bicriteria timeshare exchange<br />

problem and (ii) a polynomial-time, decentralized algorithm for “good” bicriteria<br />

solutions.<br />

2 - Cooperative Surrogate Models Improving Multi-objective<br />

Evolutionary Algorithms<br />

Saúl Zapotecas Martìnez, CINVESTAV-IPN, Mexico, D.F., Mexico,<br />

saul.zapotecas@gmail.com, Carlos A. Coello Coello<br />

We present a multi-objective evolutionary algorithm (MOEA) assisted by two<br />

different meta-models: a local and a global one. The global model is constructed<br />

by using different surrogate models. The local model is generated by using the<br />

solutions in the current population of the MOEA. The training set for each model<br />

is updated along the search of the MOEA. The two different predicted values of<br />

the functions provided by the meta-models are used to estimate the final value of<br />

each function.<br />

3 - Diversity Enhancing Evolutionary Multiobjective Search<br />

Brian Piper, North Carolina State University, 2500 Stinson Drive,<br />

Raleigh, NC, United States of America, bepiper@ncsu.edu,<br />

Ranji Ranjithan, Hana Chmielewski<br />

Besides obtaining Pareto-optimal solutions, decision diversity is an important<br />

consideration in real-world multiobjective problems. Diversity can be defined as<br />

both the spread of solutions in the decision space and degree to which alternative<br />

solutions are available. We present algorithms for obtaining diverse Paretooptimal<br />

sets and compare results for several test problems to demonstrate the<br />

effectiveness of the algorithms.<br />

4 - Satisfying Multiple Objectives in Infrastructure<br />

Management Planning<br />

Hana Chmielewski, North Carolina State University, Campus Box<br />

7908, Raleigh, NC, United States of America, htchmiel@ncsu.edu,<br />

Ranji Ranjithan<br />

Evolutionary algorithms lend themselves to solving cross-disciplinary problems<br />

with multiple objectives. In infrastructure planning, for example, it may be useful<br />

to consider the resource and performance objectives of engineers, land-use<br />

planners, and emergency managers. An algorithm that offers maximally different<br />

non-inferior management plans by preserving the diversity of solutions in the<br />

decision space is applied to aid decision-making inwastewater treatment planning.<br />

■ SA10<br />

10- West 105 B- CC<br />

Risk in Stochastic Programming<br />

Sponsor: Optimization/Stochastic Programming<br />

Sponsored Session<br />

Chair: Sitki Gulten, PhD Candidate, Rutgers University, Department of<br />

Management Science & Infor, 1 Washington Park, Newark, NJ, 07102,<br />

United States of America, sgulten@rutgers.edu<br />

1 - Two-stage Portfolio Optimization with Higher-order Conditional<br />

Measures of Risk<br />

Sitki Gulten, PhD Candidate, Rutgers University, Department of<br />

Management Science & Infor, 1 Washington Park, Newark, NJ,<br />

07102, United States of America, sgulten@rutgers.edu,<br />

Andrzej Ruszczynski<br />

Optimization of a portfolio with an option to rebalance over multiple periods<br />

from is a major problem in modern portfolio theory. In this research, different<br />

forward and backward scenario tree generation techniques are applied on<br />

multivariate GARCH-generated scenarios to construct scenario trees. Next, mean-


semideviation risk function with higher-orders is used to formulate the two-stage<br />

portfolio problem in which there are two periods and an option to rebalance<br />

between those two periods.<br />

2 - Complexity of Bilevel Coherent Risk Programming<br />

Jonathan Eckstein, Rutgers University, 640 Bartholomew Road,<br />

Piscataway, NJ, 08854, United States of America,<br />

jeckstei@rci.rutgers.edu<br />

We describe a bilevel programming approach to applying coherent risk measures<br />

to three-stage stochastic programming problems. This formulation technique<br />

avoids the time-inconsistency difficulties of naive models and the incomposability<br />

issues causing time-consistent formulations to have complicated, hard-to-explain<br />

objective functions. Unfortunately, we show that such bilevel formulations, when<br />

using the standard mean-semideviation and average-value-at-risk measures, are<br />

NP-hard.<br />

3 - Scenario Generation and Reduction Applied to Long-term<br />

Power Generation Expansion Planning with Risk<br />

Yonghan Feng, Iowa State Univseristy, 3024 Black Engr, Ames, IA,<br />

United States of America, yhfeng@iastate.edu, Sarah Ryan<br />

A stochastic program minimizes the combined expected cost and CVaR of long<br />

term power generation expansion planning. Scenarios are generated from<br />

stochastic process models of demand and natural gas price and then reduced by a<br />

new heuristic called forward selection in wait-and-see clusters (FSWC).<br />

Numerical results in a twenty-year case study indicate substantial computational<br />

savings while identifying similar solutions as those obtained by applying forward<br />

selection alone.<br />

■ SA11<br />

11- West 105 C- CC<br />

Advances in Stochastic Programming<br />

Contributed Session<br />

Chair: Alper Murat, Assistant Professor, Wayne State University, 4815<br />

4th Street, Detroit, MI, 48202, United States of America,<br />

amurat@wayne.edu<br />

1 - Simulation-based Two-stage Stochastic Programming with<br />

Recourse and Endogenous Uncertainty<br />

Tahir Ekin, PhD Candidate, The George Washington University<br />

Department of Decision Sciences, 2201 G St Funger Hall 415 NW,<br />

Washington, DC, 20052, United States of America, ekin@gwu.edu,<br />

Refik Soyer, Nicholas Polson<br />

We consider two stage stochastic recourse problems with decision dependent<br />

(endogenous) uncertainty. We develop an augmented probability simulation<br />

approach via Markov Chain Monte Carlo methods. Our approach is illustrated<br />

with a production planning problem involving continuous uncertainty and<br />

continuous first stage decision variables.<br />

2 - A New Algorithm for Moment-matching Scenario Generation<br />

with Application to Financial Optimization<br />

Diana Roman, Brunel University, Uxbridge, London,<br />

United Kingdom, diana.roman@brunel.ac.uk, Paresh Date,<br />

Ksenia Ponomoreva<br />

This method produces scenarios that match exactly the given first moment,<br />

covariance matrix, average marginal skewness and kurtosis of a random vector.<br />

Unlike previous approaches, it does not use optimization in the scenario<br />

generation process; thus it is computationally much simpler. We generate<br />

scenarios for a portfolio optimization model. Desirable properties are satisfied, e.g.<br />

in and out-of-sample stability. Optimal solutions vary only marginally with<br />

increasing number of scenarios.<br />

3 - Progressively Hedged Sample Average Approximation for<br />

Two-stage Stochastic Programs<br />

Alper Murat, Assistant Professor, Wayne State University,<br />

4815 4th Street, Detroit, MI, 48202, United States of America,<br />

amurat@wayne.edu, Nezir Aydin<br />

We present a novel hybrid heuristic method (PHSAA) for solving two-stage<br />

stochastic programs which integrates deterministic Progressive Hedging method<br />

with Sample Average Approximation. PHSAA improves over SAA by exploiting<br />

sample solution information and reducing the need to use large sample sizes.<br />

PHSAA is significantly more efficient than SAA while attaining same or better<br />

solution quality than SAA. We report on extensive results using capacitated<br />

reliable facility location problem (CRFLP).<br />

INFORMS Phoenix – 2012<br />

59<br />

■ SA12<br />

SA13<br />

12- West 106 A- CC<br />

Recent Advances in Integer Programming<br />

Sponsor: Optimization/Integer Programming<br />

Sponsored Session<br />

Chair: Sebastian Pokutta, Friedrich-Alexander-Universitat<br />

Erlangen-Nürnberg, Cauerstrasse 11, Erlangen, 91058, Germany,<br />

sebastian.pokutta@me.com<br />

1 - Solving Mixed-Integer Semidefinite Programs<br />

Lars Schewe, Dr., FAU Erlangen-Nürnberg, Cauerstr. 11, Erlangen,<br />

91058, Germany, lars.schewe@math.uni-erlangen.de, Sonja Mars<br />

We present practical solution approaches to solve mixed-integer semidefinite<br />

programs: We show that by integrating standard semidefinite solvers into the<br />

mixed-integer solver SCIP, we can harness standard methods from integer<br />

programming. We present computational results on a variety of instances.<br />

2 - Comparing Symmetry Breaking Techniques<br />

James Ostrowski, University of Tennessee, 1425 S. Stadium Dr,<br />

Knoxville, TN, 37996, United States of America, jostrows@utk.edu<br />

There are a variety of ways to break symmetry in an MILP problem. We will<br />

discuss several of these methods, and test them on a variety of highly symmetric<br />

problems.<br />

3 - The Structure of Reduced Bases for Kernel Lattices<br />

Karen Aardal, Delft University of Technology, Mekelweg 4,<br />

Delft, 2628 CD, Netherlands, K.I.Aardal@tudelft.nl,<br />

Frederik von Heymann, Andrea Lodi<br />

We consider the structure of reduced bases for lattices consisting of all integer<br />

vectors belonging to the null space of a positive integer vector. We observe that<br />

when the length is measured as the Euclidean distance, as in the standard<br />

implementation of the LLL algorithm, then the reduced basis has an Identity<br />

matrix as a submatrix. We provide a theoretical analysis, implications, and<br />

computational illustrations.<br />

4 - The Structure of Reduced Bases for Kernel Lattices:<br />

Theoretical Analysis<br />

Frederik von Heymann, Delft University of Technology, Mekelweg<br />

4, Delft, 2628 CD, Netherlands, f.j.vonheymann@tudelft.nl,<br />

Karen Aardal, Andrea Lodi, Laurence Wolsey<br />

In this presentation we continue on the topic of the previous talk. Here we<br />

present the main ingredients of the theoretical analysis and give some<br />

computational examples.<br />

■ SA13<br />

13- West 106 B- CC<br />

Stochastic Integer Programming Applications<br />

Sponsor: Optimization/Linear Programming and Complementarity<br />

Sponsored Session<br />

Chair: Burak Buke, The University of Edinburgh, School of<br />

Mathematics, King’s Buildings, JCMB, Edinburgh, United Kingdom,<br />

B.Buke@ed.ac.uk<br />

1 - A Novel Scenario Reduction Method for Two-stage<br />

Stochastic Programs<br />

Ali Koc, IBM Watson Research Center, 1101 Kitchawan Road,<br />

Yorktown Heights, NY, 10598, United States of America,<br />

akoc@us.ibm.com<br />

We present a novel scenario reduction method for two-stage stochastic programs.<br />

The objective is to minimize the bound on the worst case performance of the<br />

optimal value of the reduced problem under the original problem. The method<br />

considers both the uncertainty and the underlying optimization problem, as<br />

opposed the methods that just consider the uncertainty. We show that both the<br />

theoretical bounds and the numerical results obtained by the method are tighter<br />

than the methods in literature.<br />

2 - Reclaimed Water Network Design via Stochastic<br />

Integer Programming<br />

Weini Zhang, Systems and Industrial Engineering, University of<br />

Arizona, Tucson, AZ, 85721, United States of America,<br />

wzhang@email.arizona.edu, Guzin Bayraksan, Gunhui Chung,<br />

Kevin Lansey<br />

We model a reclaimed water distribution network for supplying treated water to<br />

the public users or agricultural areas using two-stage stochastic binary<br />

programming with random recourse. Both construction and energy costs<br />

expanded are considered. The network has spatial growth and reclaimed water<br />

demands are uncertain. A specialized algorithm is developed to exploit the


SA14<br />

structure of the network to efficiently solve the problem. Computational results<br />

are presented on a realistic problem.<br />

3 - Managing Capacity Flexibility in Make-to-Order<br />

Production Environments<br />

Fehmi Tanrisever, Eindhoven University of Technology, Den<br />

Dolech 2, Eindhoven, 5612, Netherlands, f.tanrisever@tue.nl,<br />

David Morton, Douglas Morrice<br />

We address the problem of managing flexible production capacity in an MTO<br />

manufacturing environment. We present a multi-period capacity management<br />

model where we distinguish between process and operational flexibility. Our<br />

results reveal that myopic policies may lead a firm to adopt more process<br />

flexibility. That is, process flexibility may be over-valued in the literature since it is<br />

assumed that a firm will operate optimally after the process flexibility decision.<br />

4 - Cross-training with Imperfect Training Schemes<br />

Burak Buke, The University of Edinburgh, School of Mathematics,<br />

King’s Buildings, JCMB, Edinburgh, United Kingdom,<br />

B.Buke@ed.ac.uk, Ozgur Araz, John Fowler<br />

Cross-training is an efficient way to achieve flexibility. We assume that training<br />

can be online as demand is revealed, in addition to the offline training before<br />

demand is realized. We show that if online training is as effective as offline<br />

schemes, offline training decreases as variability increases. If the effectiveness of<br />

online and offline schemes differ, offline training may increase as variability<br />

increases. We also provide a stochastic integer program to design cross-training<br />

schemes.<br />

■ SA14<br />

14- West 106 C- CC<br />

Advances in Project Management<br />

Contributed Session<br />

Chair: Bruce Pollack-Johnson, Associate Professor of Mathematics &<br />

Statistics, Villanova University, 800 Lancaster Avenue, Department of<br />

Mathematics & Statistics, Villanova, PA, 19085, United States of<br />

America, bruce.pollack-johnson@villanova.edu<br />

1 - Multi-player Project Planning and Scheduling under Risk<br />

Sharing<br />

Xin Xu, Rutgers University, 425 Mount Prospect Ave., Apt. 417,<br />

Newark, NJ, 07104, United States of America,<br />

xin.xu.2009@rutgers.edu, Yao Zhao<br />

We consider a product development project where the design work of subsystems<br />

is outsourced to suppliers by a manufacturer. We build a mathematical model to<br />

predict each firm’s behavior under a risk sharing partnership. We show that each<br />

firm tends to delay its task relative to what is the best for the entire project as a<br />

whole. We propose an alternative incentive scheme – fair sharing, to remedy the<br />

weakness of risk sharing while retaining its benefits.<br />

2 - Optimizing Team Staffing Decisions: Meeting Performance<br />

Expectations When Staffing One or Many Teams<br />

Alison Schroeder, Purdue University, 315 N Grant St.,<br />

West Lafayette, IN, 47907, United States of America,<br />

schroe32@purdue.edu, Sara McComb, Deanna Kennedy<br />

Staffing project teams from a pool of candidates with similar skills and abilities is<br />

not trivial. Moreover, managers may want to staff one team or many teams from<br />

the pool. Herein we optimize the personality-performance relationship model to<br />

determine team assignments that fulfill managerial performance expectations.<br />

Implications are discussed.<br />

3 - The Impact of Reputation on Project Selection<br />

Ali Shafahi, Graduate Student, University of Maryland at College<br />

Park, Dept. of Civil & Environmental Eng., 1173 Glenn L. Martin<br />

Hall, College Park, MD, 20740, United States of America,<br />

ashafahi@umd.edu, Ali Haghani, Masoud Hamedi<br />

Contractor’s reputation is one of the contributing factors in project selection. This<br />

study takes advantage of an optimization model that considers monetary as well<br />

as non-monetary criteria. To investigate relative importance of reputation to profit<br />

on the project selection decision, the model is applied to a set of sample problems.<br />

The decision making framework and results of sensitivity analysis are presented.<br />

INFORMS Phoenix – 2012<br />

60<br />

4 - Project Planning and Scheduling to Maximize Quality in the<br />

Presence of Cost Overruns and Time Delays<br />

Bruce Pollack-Johnson, Associate Professor of Mathematics &<br />

Statistics, Villanova University, 800 Lancaster Avenue, Department<br />

of Mathematics & Statistics, Villanova, PA, 19085,<br />

United States of America, bruce.pollack-johnson@villanova.edu,<br />

Matthew Liberatore<br />

We present research designed to help deal with significant cost overruns and time<br />

delays. In such circumstances the overall quality of a project is most likely to<br />

suffer. We present strategies for dealing with such undesirable situations to<br />

minimize the reduction in the overall project quality by applying different project<br />

planning and scheduling models that evaluate the tradeoffs between quality, time,<br />

and cost.<br />

■ SA15<br />

15- West 202- CC<br />

Software Demonstration<br />

Invited Session<br />

1 - AMPL Optimization - Specifying “Logical” Conditions in AMPL<br />

Optimization Models<br />

Robert Fourer, President, AMPL Optimization, Inc, 2145 Sheridan<br />

Road, Evanston IL, United States of America, 4er@ampl.com<br />

Optimization modelers are often stymied by the complications of converting<br />

problem logic into algebraic constraints suitable for solvers. The AMPL modeling<br />

language thus allows various logical conditions to be described directly.<br />

Additionally a new interface to the ILOG CP solver handles logic in a natural<br />

way not requiring conventional transformations.<br />

2 - Palisade Corporation - Avoiding Failure: using @RISK to<br />

Identify, Analyze and Manage Risk More Successfully<br />

Rafael Hartke, Oil and Energy Industry Consultant, Palisade<br />

Corporation, 798 Cascadilla Street, Ithaca, NY 14850,<br />

United States of America, dsprague@schwartzmsl.com<br />

Projects fail. They often fail for a lack of effective planning, either because of<br />

excess optimism in terms of time, cost and performance or because of extra work<br />

in the plan in terms of scope, resources and unforeseen events. @RISK employs<br />

Monte Carlo based simulation to give insight through sophisticated statistical<br />

analysis of the various potential outcomes. Understanding range outcomes facilitates<br />

effective risk management, prioritizing critical risks and managing expectations.<br />

■ SA16<br />

16- West 207- CC<br />

Multiple Criteria Decision Making: Foundations and<br />

Some Approaches<br />

Cluster: Tutorials<br />

Invited Session<br />

Chair: Murat Köksalan, METU, IE Department, METU, Ankara, Turkey,<br />

koksalan@ie.metu.edu.tr<br />

1 - Multiple Criteria Decision Making: Foundations and<br />

Some Approaches<br />

Murat Köksalan, METU, IE Department, METU, Ankara, Turkey,<br />

koksalan@ie.metu.edu.tr, Jyrki Wallenius<br />

In this tutorial we cover the foundations of Multiple Criteria Decision Making and<br />

define and demonstrate basic concepts. We classify approaches based on the<br />

problem structure as well as on the way decision maker’s preferences are elicited.<br />

We discuss some approaches, emphasizing the interactive approaches. We<br />

demonstrate the concepts and approaches together with illustrative examples and<br />

graphs and we provide information about further resources and references.


■ SA17<br />

17- West 208 B- CC<br />

Stochastic Programming with Random or<br />

Ambiguous Data<br />

Sponsor: Optimization/Stochastic Programming<br />

Sponsored Session<br />

Chair: Siqian Shen, Assistant Professor, University of Michigan,<br />

2793 IOE Building, 1205 Beal Avenue, Ann Arbor, MI, 48103,<br />

United States of America, siqian@umich.edu<br />

1 - Models and Algorithms for the Balance-Constrained Stochastic<br />

Bottleneck Spanning Tree Problem<br />

Jue Wang, Industrial and Operations Engineering, University of<br />

Michigan, 1205 Beal Avenue, Ann Arbor, MI, 48109, United States<br />

of America, juewang@umich.edu, Siqian Shen, Murat Kurt<br />

This paper studies chance-constrained formulations of the BCSBSTP with<br />

independently distributed arc weights, and reformulates them as MINLPs. We<br />

employ SOS1 and SOS2 variables to approximate nonlinearity with linear<br />

constraints, and compare the results with an SAA-based MIP reformulation of the<br />

orignal problem. In general, SOS1 computationally performs better than the other<br />

two approximation approaches, tested on random network instances with various<br />

distribution settings of arc weights.<br />

2 - Target Oriented Optimization in Inventory Management<br />

Zhuoyu Long, NUS Business School, Singapore,<br />

longzhuoyu@nus.edu.sg, Lucy Gongtao Chen, Georgia Perakis,<br />

Melvyn Sim<br />

In this study we investigate the impact of target on both one-period and multiperiod<br />

inventory management problems. We develop target-oriented decision<br />

criteria to model the effect of target. For the one-period (newsvendor) problem,<br />

the result from our theoretical model is consistent with experimental findings. For<br />

the multi-period problem, we incorporate the financing decisions, and report<br />

favorable computational results for using targets in regulating uncertain<br />

consumptions over time.<br />

3 - Data-driven Chance Constrained Stochastic Program<br />

Ruiwei Jiang, University of Florida, 411 Weil Hall, University of<br />

Florida, Gainesville, FL, 32611, United States of America,<br />

rwjiang@ufl.edu, Yongpei Guan<br />

Chance constraint is a convenient modeling tool of decision making under<br />

uncertainty. In practice, instead of knowing the true distribution of a random<br />

parameter, only a series of historical data sampled from the ambiguous<br />

distribution are available. In this talk, we develop exact approaches to reformulate<br />

the Data-driven Chance Constraints (DCC) based on historical data.<br />

■ SA18<br />

18- West 208 A- CC<br />

Applied Network Optimization Methodologies<br />

Contributed Session<br />

Chair: Isil Kirkizoglu, Middle East Technical University, Industrial<br />

Engineering Department, Ankara, 06800, Turkey,<br />

isilkirkizoglu@gmail.com<br />

1 - A New Branch & Bound Approach for the Traveling Repairman<br />

Problem<br />

Stefan Bock, Professor, Chair of Business Computing and<br />

Operations Research, University of Wuppertal, Gauflstrafle 20,<br />

Wuppertal, Germany, sbock@winfor.de<br />

This talk studies a special case of the well-known Traveling Repairman Problem.<br />

Specifically, while processing times at the customer locations are neglected, each<br />

customer has to be serviced not before a predetermined release date and,<br />

depending on the considered problem variant, not after a given due date. In order<br />

to solve the problem, a new best first Branch&Bound approach is proposed. Its<br />

efficiency is validated by means of computational tests.<br />

2 - Travelling Salesman Problems in Dynamic Environment<br />

Eran Simhon, Technion, Technion City, Haifa, HA, 32000, Israel,<br />

simhon@bu.edu, Shraga Shoval, Liron Yedidsion<br />

In the last 20 years there has been a growing interest in the field of Moving Target<br />

Traveling Salesman Problem (MT-TSP), in which targets move at fixed velocities.<br />

In this research we study the Resupply MT-TSP, in which the agent must visit the<br />

origin after each interception. We prove that the offline version is strongly NPhard<br />

and that the online version is unbounded. We also show the equivalence of<br />

special cases of the problem to scheduling problems with deteriorating jobs.<br />

INFORMS Phoenix – 2012<br />

61<br />

SA19<br />

3 - Benders Decomposition for a Splitter Location-allocation<br />

Problem in Fiber Optic Access Networks<br />

Sachin Jayaswal, Assistant Professor, Indian Institute of<br />

Management Ahmedabad, Vastrapur, Ahmedabad, Gu, 380015,<br />

India, sachin@iimahd.ernet.in, Astha Airan<br />

We propose a Benders Decomposition based algorithm to solve the Splitter<br />

Location-Allocation Problem in Fiber Optic Access Networks. Our numerical<br />

results are very encouraging: our proposed Benders Decomposition helps achieve<br />

the optimal solution for large problem instances in couple of seconds which<br />

CPLEX is unable to solve using the original MIP model even in an hour.<br />

4 - Parametric Programming Approach to Gene Expression<br />

Clustering using the Clique Partitioning Problem<br />

Victoria Ellison, North Carolina State University, Raleigh, NC,<br />

27605, United States of America, vmelliso@ncsu.edu, Yahya Fathi,<br />

Yoshitsugu Yamamoto, Amy Langville<br />

We introduce a parametric programming based algorithm to solving a binary<br />

integer linear programming (BILP) formulation of the Clique Partitioning<br />

Problem, for the purpose of gene expression clustering. We derive various<br />

structural properties regarding the existence and optimality of binary solutions to<br />

the linear relaxation of the BILP. Using linear programming sensitivity analysis we<br />

derive a measure of closeness between patients of similar and different disease<br />

subtypes.<br />

5 - Discretization for Heat Exchanger Network Design with<br />

Equipment Configuration<br />

Isil Kirkizoglu, Middle East Technical University, Industrial<br />

Engineering Department, Ankara, 06800, Turkey,<br />

isilkirkizoglu@gmail.com, Haldun Sural, Sinan Gurel<br />

This study presents an optimization approach to a chemical engineering process<br />

design problem. We propose a flexible solution approach for heat exchanger<br />

network design with detailed equipment configuration. It involves discretization<br />

of temperatures based on heat load equality and formulation of a shortest-path<br />

problem rather than dealing with nonlinearity at the network design level, a<br />

common method in the literature. Computational results are provided.<br />

■ SA19<br />

19- West 211 A- CC<br />

Joint Session Healthcare Logistics/SPPSN: Vehicle<br />

Routing in Healthcare Applications<br />

Cluster: Healthcare Logistics & Public Programs, Service and Needs<br />

Invited Session<br />

Chair: Ali Ekici, University of Houston, Department of Industrial<br />

Engineering, Houston, TX, United States of America,<br />

aekici@central.uh.edu<br />

1 - A Constant-factor Approximation Algorithm for Multi-vehicle<br />

Collection for Processing Problem<br />

Lerzan Ormeci, Koc University, Rumeli Feneri Yolu, Sariyer,<br />

Istanbul, 34450, Turkey, LORMECI@ku.edu.tr, Esma Gel,<br />

Sibel Salman, Eda Yucel<br />

In multiple vehicle collection for processing problem, items accumulate at a set of<br />

sites and are transferred through a series of tours of multiple vehicles to a<br />

processing facility to be processed. We show that the problem with the makespan<br />

objective is NP-hard, and propose a polynomial-time, constant-factor<br />

approximation algorithm for its solution.<br />

2 - Managing Blood Collection Operations<br />

Ali Ekici, University of Houston, Department of Industrial<br />

Engineering, Houston, TX, United States of America,<br />

aekici@central.uh.edu, Orsan Ozener, Gultekin Kuyzu<br />

In this paper, motivated by the practices in blood supply management, we study a<br />

variant of the vehicle routing problem. Considering processing requirements of<br />

donated whole blood in order to extract platelets, we analyze the pickup<br />

operations from donation centers and develop algorithms to maximize the platelet<br />

production.<br />

3 - A New Approach for Routing Courier Delivery Services with<br />

Urgent Demand<br />

Chen Wang, University of Southern California, University Park<br />

Campus, Los Angeles, CA, 90007, United States of America,<br />

Wang20@usc.edu, Fernando Ordonez, Maged Dessouky<br />

The courier delivery industry is faced with random demand, as well as urgent<br />

requests. An example of such application is the transportation of medical<br />

specimens. We propose better vehicle routing solutions that can efficiently satisfy<br />

random demand and urgent requests. We formulate a multi-trip vehicle routing<br />

problem, and devise a heuristic based on insertion and Tabu search. Simulations<br />

on randomly generated data and on real-world data show significant<br />

improvement from existing methods.


SA20<br />

■ SA20<br />

20- West 211 B- CC<br />

Joint Session: SPPSN/ENRE-Environment:<br />

Energy Policy and Sustainability<br />

Sponsor: Public Programs, Service and Needs & Energy,<br />

Natural Res & the Envi/ Environment and Sustainability<br />

Sponsored Session<br />

Chair: Erin Baker, University of Massachusetts, Amherst, MA,<br />

United States of America, edbaker@ecs.umass.edu<br />

1 - Decommissioning and Repowering Decisions for Renewable<br />

Power Producers<br />

Chenlu Lou, Iowa State University, 3004 Black, Ames, IA, 50011,<br />

United States of America, clou@iastate.edu, K. Jo Min<br />

There have been substantial increases in the construction and operation of wind<br />

farms across the U.S.A. and the world, which will lead to a significant number of<br />

wind farm decommissioning and repowering decisions soon. We formulate and<br />

analyze mathematical models from a real options perspective with the operation<br />

and maintenance cost following the geometric Brownian motion process, and<br />

derive managerial insights for relevant government policy makers.<br />

2 - Hydrogen Production Facility Network Design from Stochastic<br />

Green Energy Supply Source<br />

Jorge Barnett Lawton, Zaragoza Logistics Center, C/ Bari 55, Plaza,<br />

Edificio Nayade, Portal 5, Zaragoza, 50197, Spain,<br />

jbarnett@zlc.edu.es, Mozart Menezes, Jarrod Goentzel<br />

Hydrogen has been identified as a clean alternative to store energy from volatile<br />

sources. We analyze the production and distribution network design problem of a<br />

firm generating electricity from wind and producing hydrogen by electrolysis, in<br />

the presence of stochastic energy prices and supply. We provide solution<br />

approaches using column generation, and use our model to evaluate a future<br />

hydrogen supply chain in Spain, under different distribution policies and<br />

government incentive schemes.<br />

3 - R&D Portfolio Analysis of Low Carbon Energy Technologies for<br />

Climate Change Mitigation<br />

Rose Zdybel, University of Massachusetts-Amherst, 120D Marston<br />

Hall, Amherst, MA, United States of America, rozoe@msn.com<br />

We analyze R&D portfolios of low carbon advanced energy technologies for<br />

climate change mitigation. We use the GCAM integrated assessment model to<br />

analyze the effects of combinations of low carbon energy technologies on CO2<br />

concentration stabilization costs and then combine the results with probabilistic<br />

data from expert elicitations. We also develop econometric relationships between<br />

variables to estimate results for input values other than those that are part of the<br />

elicitations.<br />

4 - A Decision Support System for Managing Wind-turbines with<br />

Storage in Smart-grids<br />

Frederic Murphy, Professor, Temple University, Alter Hall 435,<br />

Philadelphia, PA, 19122, United States of America,<br />

fmurphy@temple.edu, Fernando Oliviera<br />

We analyze the wind-turbine business model given the opportunities created by<br />

the smart grid and by efficient electric battery storage systems. We model the<br />

interaction between dynamic prices and wind-regimes; we analyze how batteries<br />

can be used to improve wind-turbines reliability and profitability. We study how<br />

forward and option contracts can be used by a wind-turbine to hedge risk and we<br />

use conditional value at risk to assess the wind-turbine risk exposure and as a<br />

basis for risk-hedging.<br />

■ SA21<br />

21- West 212 A- CC<br />

Applications of Networks and Graphs<br />

Contributed Session<br />

Chair: Zeynep Ertem, Texas A&M University, Industrial & Systems<br />

Engineering, 3131 TAMU, College Station, TX, 77843,<br />

United States of America, zeynep84@tamu.edu<br />

1 - Detecting Research Fronts using Citation Network Analysis<br />

Katsuhide Fujita, The University of Tokyo, 2-11-16 Yayoi,<br />

Bunkyo-ku, Tokyo, 113-8656, Japan, fujita@ipr-ctr.t.u-tokyo.ac.jp,<br />

Yuya Kajikawa, Junichiro Mori, Ichiro Sakata<br />

One of the important methodologies for detecting the research fronts is the<br />

citation network analysis. Especially, citation network analysis with<br />

combinational types or weights has possibilities of finding the new research fronts<br />

compared with non-weighted and single type of citation networks. We perform a<br />

comparative study to investigate the each type of citation networks in detecting a<br />

research front using visibility, speed, topological relevance and keyword similarity.<br />

INFORMS Phoenix – 2012<br />

62<br />

2 - Social Network Analysis at Wine and Food Festival<br />

Bomi Kang, Associate Professor, Coastal Carolina University,<br />

P O Box 261954, Conway, SC, United States of America,<br />

bkang@coastal.edu, Young Jae Kim, Taylor Damonte<br />

Social network analysis emphasizes the importance of constructing the<br />

interconnectedness among concepts and knowledge networks in respondents’<br />

minds. The technique has gained popular use in social science over the past three<br />

decades. Using concept maps and degree centralities derived from social network<br />

analysis, authors demonstrated new insights in festivals in Myrtle Beach Area,<br />

through this novel technique.<br />

3 - Traffic Grooming in Optical Networks: Decomposition and<br />

Partial LP Relaxation<br />

Hui Wang, PhD Candidate, North Carolina State University, 2152<br />

Burlington Labs, Raleigh, NC, 27695, United States of America,<br />

hwang4@ncsu.edu, George Rouskas<br />

We consider the traffic grooming problem, a fundamental network design<br />

problem in optical networks. We propose a new decomposition approach with<br />

two subproblems: (1) virtual topology and traffic routing (VTTR), and (2) routing<br />

and wavelength assignment (RWA). We also propose an ascending utilization<br />

iterative algorithm based on partial LP relaxation to further improve the<br />

scalability of VTTR. Our approach delivers a desirable tradeoff between running<br />

time and quality of the final solution.<br />

4 - Graph Theoretical Analysis of Brain Networks<br />

Zeynep Ertem, Texas A&M University,Industrial & Systems<br />

Engineering, 3131 TAMU, College Station, TX, 77843,<br />

United States of America, zeynep84@tamu.edu, Sergiy Butenko<br />

Exploring the connectivity patterns of human brain is gaining more interest in the<br />

last decade. Correlated low frequency fluctuations in the blood oxygenation level<br />

dependent signal have been widely observed in connected brain regions. Resting<br />

state functional magnetic resonance imaging (R-fMRI) consists of hundreds of<br />

time periods for thousands of image voxels. Our aim is to model the brain as a<br />

complex network. The clusters are identified with graph theoretical analysis.<br />

■ SA22<br />

22- West 212 B- CC<br />

Topics in Real Time and Embedded Computing<br />

Sponsor: Computing Society<br />

Sponsored Session<br />

Chair: Alex Mills, Indiana University Kelley School of Business, 1309 E.<br />

Tenth Street, Bloomington, IN, 47405, United States of America,<br />

millsaf@indiana.edu<br />

1 - Optimization-based Frameworks for Dynamic Configuration of<br />

Real-time Systems with Energy Constraints<br />

Eduardo Camponogara, Professor, Federal University of Santa<br />

Catarina, Cx. P. 476, Florianopolis, 88040, Brazil,<br />

camponog@das.ufsc.br, Riad Nassiffe, George Lima<br />

Embedded real-time systems powered by batteries require suitable support for<br />

energy-savings at the operating system level. Mechanisms to do so must take into<br />

consideration not only energy constraints but also schedulability since tasks must<br />

execute within predefined time windows. Further, it is desired that application<br />

quality of service (QoS) is optimized. This talk presents two optimization-based<br />

frameworks for maximizing application QoS subject to both schedulability and<br />

energy constraints.<br />

2 - Can Randomness Buy Clairvoyance? Stochastic Scheduling of<br />

Mixed Criticality Real-time Job Systems<br />

Bader Al-Ahmad, PhD Student, University of British Columbia,<br />

2205 Lower Mall, P.O. Box 70, Vancouver, BC, V6T1Z4, Canada,<br />

baderalahmad84@gmail.com, Sathish Gopalakrishnan<br />

We pose the problem of stochastically scheduling mixed criticality jobs when job<br />

execution time distributions at all criticality levels are given. By stochastic, the<br />

dynamical evolution of the system criticality level over time is captured by a<br />

stochastic process. We ask: is such information any beneficial in reducing the<br />

pessimism of current deterministic algorithms? Our objective is to match as<br />

closely the performance of a powerful oracle that knows the future system<br />

behavior realization.<br />

3 - Temporal Logic Testing for Cyber-physical Systems<br />

Georgios Fainekos, Arizona State University,<br />

699 S. Mill Ave., Tempe, AZ, 85281, United States of America,<br />

Georgios.Fainekos@asu.edu, Sriram Sankaranarayanan<br />

One of the major challenges in Model Based Development (MBD) of Cyber-<br />

Physical Systems (CPS) is the verification of real-time functional system<br />

properties. In general, the problem is undecidable due to the interplay between<br />

continuous and discrete system dynamics. In this talk, we present how the<br />

problem of verification can be posed as an optimization problem which can be<br />

solved using stochastic optimization techniques including Monte-Carlo methods<br />

and the Cross Entropy method.


■ SA23<br />

23- West 212 C- CC<br />

Survivable Networks<br />

Sponsor: Telecommunications<br />

Sponsored Session<br />

Chair: Abdulah Konak, Pennsylvania State Berks, Tulpehocken Road,<br />

P.O. Box 7009, Reading, PA, 19610, United States of America,<br />

auk3@psu.edu<br />

1 - Survivable Capacitated Layered Networks with Spanning<br />

Tree Protection<br />

Tachun Lin, Cameron University, 2800 W Gore Blvd, Lawton, OK,<br />

73505, United States of America, tlin@cameron.edu, Zhili Zhou,<br />

Krishnaiyan Thulasiraman<br />

In this paper, we study the survivability problem in capacitated layered networks.<br />

We propose necessary and sufficient conditions for the existence of survivable<br />

routing with upper-layer protection, formulate this problem as a mixed-integer<br />

program, and design a novel upper-layer spanning tree protection algorithm<br />

which guarantees the upper-layer network connectivity and generates routings<br />

within lower-layer capacity. Computational experiments demonstrate the<br />

efficiency of our algorithm.<br />

2 - Resilience: A New Metric to Evaluate Network<br />

Reliability/Survivability<br />

Ozgur Kabadurmus, Auburn University, 3333 Shelby Center,<br />

Auburn, AL, 36849, United States of America,<br />

ozk0001@tigermail.auburn.edu, Alice E. Smith<br />

In telecommunication network design problems, survivability and reliability are<br />

used to evaluate quality of service. In this study, a new metric that combines<br />

network reliability with network resilience is presented to measure<br />

reliability/survivability more effectively. It is compared with well-known network<br />

reliability/survivability metrics, namely k-connectivity and two terminal<br />

reliability, and its benefits and computational efficiency are discussed.<br />

3 - Lexicographical Minimization of Routing Hops in Hopconstrained<br />

Node Survivable Networks<br />

Luis Eduardo Neves Gouveia, CIO and DEIO, Cidade Universiteria,<br />

Bloco C6, Campo Grande, Lisbon, 1749-016, Portugal,<br />

legouveia@fc.ul.pt, Pedro Patricio, Amaro de Sousa<br />

We address the following traffic engineering problem: how to route deterministic<br />

changes of original demands in a pre-dimensioned network, maintaining network<br />

survivability and QoS, while minimizing the number of hops of either i) all<br />

service paths or ii) the worst service path for each commodity, in a lexicographical<br />

sense. We present and discuss two classes of Integer Linear Programming models<br />

for this problem and computational results considering several traffic demand<br />

settings.<br />

4 - A Network Support System for Ad-hoc Networks using<br />

Autonomous Intelligence Agents<br />

Abdulah Konak, Pennsylvania State Berks, Tulpehocken Road,<br />

P.O. Box 7009, Reading, PA, 19610, United States of America,<br />

auk3@psu.edu<br />

This paper presents a decentralized approach to maintain the connectivity of a<br />

MANET using autonomous, intelligent agents. Concepts from the social network<br />

analysis along with flocking algorithms are utilized to maintain the connectivity<br />

of mobile nodes. Computational results are presented to demonstrate the effect of<br />

various local agent behaviors on the global network connectivity.<br />

■ SA24<br />

24- West 213 A- CC<br />

Advances in Modeling and Optimal Control of<br />

Infectious Disease Spread<br />

Sponsor: Health Applications Society<br />

Sponsored Session<br />

Chair: Reza Yaesoubi, Post-Doctoral Research Fellow,<br />

Harvard Medical School, 641 Huntington Ave., Boston, MA, 02115,<br />

United States of America, reza.yaesoubi@gmail.com<br />

1 - A Model for Optimal Allocation of HIV Prevention and<br />

Treatment Funds<br />

Margaret Brandeau, Stanford University, Huang Engineering<br />

Center, Stanford, CA, 94305, United States of America,<br />

brandeau@stanford.edu, Sabina Alistar, Elisa Long, Eduard Beck<br />

We develop a model to determine the optimal allocation of resources between<br />

HIV prevention and treatment services to minimize the basic reproduction<br />

number. Our model includes multiple populations with different transmission<br />

modes, as well as production functions that relate investment in prevention and<br />

INFORMS Phoenix – 2012<br />

63<br />

SA25<br />

treatment to changes in transmission and treatment rates. We apply our model to<br />

examine HIV epidemic control in two different settings, Uganda and Russia.<br />

2 - Evaluating the Effectiveness of Interventions During an<br />

Influenza Pandemic<br />

Anna Teytelman, PhD Student, Massachusetts Institute of<br />

Technology, Operations Research Center, Cambridge, MA, 02139,<br />

United States of America, teytanna@mit.edu, Richard Larson<br />

With pandemic influenza, pharmaceutical and non-pharmaceutical resources are<br />

limited. We present dynamic, multi-regional, vaccine allocation schemes for the<br />

USA. For single communities with heterogeneous populations, we examine the<br />

effects of timing and targeting strategies on reaching herd immunity. We conclude<br />

with strategies for combining vaccines with non-pharmaceutical interventions<br />

such as hand-washing, public awareness campaigns and school closures to<br />

decrease intensity of an outbreak.<br />

3 - Resource Allocation for Optimal Control of Epidemics:<br />

Can Treatment Compete?<br />

Sabina Alistar, Stanford University, P.O. Box 17244, Stanford, CA,<br />

94309, United States of America, ssabina@stanford.edu<br />

Controlling infectious diseases such of HIV requires judicious resource allocation<br />

between treatment and prevention. We use an optimal control approach to<br />

determine how the allocation decision will change over time, as an epidemic<br />

evolves. Our model considers several epidemiological objectives relevant in<br />

practice, and non-linear epidemic dynamics. We characterize the optimal<br />

solution, identify conditions for optimality, and provide numerical examples.<br />

4 - A Framework for Real-time Decision Making During Epidemics<br />

Reza Yaesoubi, Post-Doctoral Research Fellow,<br />

Harvard Medical School, 641 Huntington Ave., Boston, MA,<br />

02115, United States of America, reza.yaesoubi@gmail.com,<br />

Ted Cohen<br />

We propose a novel framework for optimizing decisions during infectious disease<br />

epidemics based on real-time observations from the epidemic and resource<br />

availability. The framework is flexible and can incorporate diseases of varying<br />

natural history and a broad range of interventions. Using influenza and<br />

tuberculosis as examples, we demonstrate how the framework can be used to<br />

inform decisions to optimize population health within constraints imposed by<br />

resource availability.<br />

■ SA25<br />

25- West 213 B- CC<br />

Optimization Methods in Radiation Therapy<br />

Sponsor: Health Applications Society<br />

Sponsored Session<br />

Chair: Timothy Chan, Assistant Professor, University of Toronto,<br />

5 King’s College Rd, Toronto, Canada, tcychan@mie.utoronto.ca<br />

1 - Imaging Based Treatment Plan Optimization for Glioblastoma<br />

Jan Unkelbach, Massachusetts General Hospital, 30 Fruit Street,<br />

Boston, MA, United States of America, junkelbach@partners.org,<br />

Bjoern Menze, Ender Konukoglu, Helen Shih<br />

Treatment planning for radiotherapy consists of two problems: 1) determining<br />

external beam parameters to realize a desired dose distribution, and 2)<br />

determining the desired dose distribution from clinical and biological data<br />

including dose-response relations, imaging data, or histology. Quantitative<br />

approaches to integrate these sources of data involve both mathematical modeling<br />

approaches a well as statistical machine learning methods. This approach is<br />

discussed for treatments of gliomas.<br />

2 - Spatiotemporally Adaptive Radiotherapy for Hypoxic Tumors<br />

Fatemeh Saberian, University of Washington, Seattle, WA,<br />

United States of America, saberian@uw.edu, Archis Ghate<br />

Lack of oxygen (hypoxia) decreases tumor radiosensitivity and hence can reduce<br />

treatment efficacy. We present a stochastic control approach to design treatment<br />

plans that adapt to spatiotemporal variations in hypoxia.<br />

3 - Beam Orientation Optimization in Radiation Therapy<br />

Treatment Planning<br />

Troy Long, Student, University of Michigan, 1205 Beal Ave.,<br />

Room 1791, Ann Arbor, MI, 48109, United States of America,<br />

troylong@umich.edu, Edwin Romeijn<br />

Beam orientation optimization selects stationary beam positions to produce a both<br />

high quality and efficiently deliverable treatment plan, resulting in a large-scale<br />

combinatorial optimization problem. We study an efficient method for selecting<br />

beam orientations for IMRT treatments that explicitly incorporates the quality of<br />

the resulting optimal dose distribution.


SA26<br />

4 - Optimal Magnetic Sweeping Design for Metastatic Cancer<br />

Tumor Treatment<br />

So Yeon Chun, Assistant Professor, Georgetown University,<br />

McDonough School of Business, 37th and O Streets, Washington<br />

DC, 20057, United States of America, sc1286@georgetown.edu,<br />

Alek Nacev<br />

Metastatic cancer is cancer that has spread from the place where it first started to<br />

another place in the body. Patients with metastatic cancer have thousands of<br />

tumors spread throughout their body and it is recognized that many of these<br />

tumors are poorly vascularized compared to normal tissues. To improve poor<br />

chemotherapeutic efficacy in metastases, we control magnets to sweep<br />

chemotherapy. We analyze autopsy data of thousands of tumors and optimize<br />

magnetic pulling treatment parameters.<br />

■ SA26<br />

26- North 221 A- CC<br />

Inventory Models and Forecast Updating<br />

Sponsor: Manufacturing & Service Oper Mgmt<br />

Sponsored Session<br />

Chair: Gad Allon, Northwestern University,<br />

2001 Sheridan Rd, Evanston, IL, United States of America,<br />

g-allon@kellogg.northwestern.edu<br />

1 - Is More Inventory Information Better? Impact of Downstream<br />

Data on Upstream Supply Forecast Accuracy<br />

Ruomeng Cui, PhD Student, Northwestern University, 2001<br />

Sheridan Rd, Evanston, IL, 60208, United States of America, rcui@kellogg.northwestern.edu,<br />

Jan Van Mieghem, Gad Allon,<br />

Achal Bassamboo<br />

We investigate the improvement of forecast accuracy of the upstream supplier’s<br />

shipment by using downstream retailer data for a beverage drink company.<br />

2 - Emergency Inventory Pooling<br />

Jordan Tong, Assistant Professor, University of Wisconsin-Madison,<br />

975 University Avenue, Madison, WI, 53706, United States of<br />

America, jtong@bus.wisc.edu, Jing-Sheng Song, Fang Liu<br />

Organizations contract with vendors to always maintain a minimum level of<br />

inventory for disaster preparedness. We consider the problem of how to manage<br />

this emergency inventory among multiple vendors. Instead of stockpiling, we<br />

show that a type of virtual pooling we call emergency inventory pooling can<br />

reduce costs. We identify the optimal policy and derive an algorithm for<br />

implementation. Finally, we examine for which firms and products emergency<br />

inventory pooling is most valuable.<br />

3 - Multi-item Closed-loop Inventory Control with Forecast<br />

Updates: A Model for DVD-by-Mail Services<br />

Li Chen, Assistant Professor, Duke University, 100 Fuqua Drive,<br />

Durham, NC, 27708, United States of America, li.chen@duke.edu,<br />

Safak Yucel, Kaijie Zhu<br />

In this paper, we present a multi-item forecasting-inventory model for a DVD-bymail<br />

service provider (such as Netflix). Our inventory model features a two-sided<br />

fixed cost for each item and a multi-item service constraint. We propose an<br />

innovative forecasting algorithm and an effective heuristic for this problem.<br />

Simulation studies show that a significant performance improvement is achieved<br />

by the new forecasting algorithm and the multi-item optimization heuristic.<br />

■ SA27<br />

27- North 221 B- CC<br />

Information Economics and Operations<br />

Sponsor: Manufacturing & Service Oper Mgmt<br />

Sponsored Session<br />

Chair: Wenqiang Xiao, Assistant Professor, New York University, 44 W<br />

4 Street, KMC 8-72, New York, NY, 10012, United States of America,<br />

wxiao@stern.nyu.edu<br />

1 - Efficient Supplier or Responsive Supplier? Analysis of Sourcing<br />

Strategies under Competition<br />

Fuqiang Zhang, Olin Business School, Washington University,<br />

St. Louis, MO, United States of America, Fzhang22@wustl.edu,<br />

Xiaole Wu<br />

Motivated by the recent trend of backshoring, this paper studies a sourcing game<br />

where competing firms may choose between efficient sourcing (e.g., sourcing<br />

from an international supplier) and responsive sourcing (e.g., sourcing from a<br />

domestic supplier). By characterizing the equilibrium outcome, we find some<br />

interesting results driven by the information structure of the sourcing game.<br />

INFORMS Phoenix – 2012<br />

2 - Signaling to Partially Informed Investors in the Newsvendor<br />

Model<br />

William Schmidt, Harvard Business School, Wyss House,<br />

Boston, MA, 02163, United States of America, wschmidt@hbs.edu,<br />

Vishal Gaur, Ananth Raman, Richard Lai<br />

We investigate the effect of short-term objectives and incomplete information on<br />

a firm’s operational decisions. We incorporate the newsvendor model using<br />

discrete stocking quantities into a signaling game and identify the circumstances<br />

under which the firm’s choice of stocking quantity purposefully does not<br />

maximize expected profits. Our model provides analytical support for the<br />

abundant anecdotal evidence that superior firms will knowingly under-invest in<br />

capacity under certain circumstances.<br />

3 - Stocking More versus Less: The Roles of Demand Volatility and<br />

Profit Margin under Market Valuation<br />

Wenqiang Xiao, Assistant Professor, New York University, 44 W 4<br />

Street, KMC 8-72, New York, NY, 10012, United States of America,<br />

wxiao@stern.nyu.edu, Guoming Lai<br />

We study the effects of asymmetric information of demand volatility on the<br />

inventory decision of a public firm who cares about not only its operational<br />

profits but also its market value. We find that the firm, when it faces a high<br />

demand volatility (less efficient), overstocks if the profit margin is low and<br />

understocks if the profit margin is high, while the firm with a low demand<br />

volatility (more efficient) may either overstock or understock in both cases.<br />

■ SA28<br />

28- North 221 C- CC<br />

Managing Manufacturing and Related Services<br />

Sponsor: Manufacturing & Service Oper Mgmt<br />

Sponsored Session<br />

Chair: Opher Baron, University of Toronto, 105 St George Street,<br />

Toronto, ON, Canada, Opher.Baron@rotman.utoronto.ca<br />

Co-Chair: Philipp Afeche, Rotman School of Management, University<br />

of Toronto, 105 St.George Street, Toronto, ON, M5S3E6, Canada,<br />

Philipp.Afeche@Rotman.Utoronto.Ca<br />

1 - Reverse Logistics and Warranty Matching in a Large Consumer<br />

Electronic Retailer<br />

Andre Calmon, Massachusetts Institue of Technology, 77<br />

Massachusetts Avenue, Bldg. E40-149, Cambridge, MA, 02139,<br />

United States of America, acalmon@mit.edu, Stephen Graves<br />

We describe, model and optimize the reverse logistics of our industrial partner, a<br />

Fortune 500 company that sells consumer electronics. Based on real data, we<br />

introduce a discrete-time model that captures the dynamics of this reverse<br />

logistics system. In addition, using an approximate dynamic programming<br />

approach, we propose a closed-loop data-driven policy for managing inventory.<br />

The performance of this policy is analysed theoretically and through numerical<br />

experiments.<br />

2 - The Assortment Packing Problem: Multiperiod Assortment<br />

Planning for Short-Lived Products<br />

Victor Martinez de Albeniz, Associate Professor, IESE Business<br />

School, Av. Pearson 21, Barcelona, 08034, Spain,<br />

valbeniz@iese.edu, Felipe Caro, Paat Rusmevichientong<br />

Retailers introduce new items to refresh product lines and maintain their market<br />

share. We study how a firm must decide, in advance, the release date of each<br />

product in a given collection over a selling season. Our formulation models the<br />

trade-offs among profit margins, preference weights, and limited life cycles. A key<br />

aspect of the problem is that each product is short-lived in the sense that, once<br />

introduced, its attractiveness lasts only a few periods and vanishes over time.<br />

3 - The Economics of Joint Production in Services<br />

Guillaume Roels, Assistant Professor, UCLA, 110 Westwood Plaza,<br />

Los Angeles, 90095, United States of America,<br />

guillaume.roels@anderson.ucla.edu<br />

In this talk, we propose a classification of services based on the degree of<br />

complementarity or substitutability between the provider’s and the client’s efforts.<br />

We study how efforts change when they become more complementary and when<br />

their distribution shifts from the service provider to the client. We identify nonmonotone<br />

effects of these changes, revealing a trade-off between operational<br />

efficiency, leading to more specialization, and complementarity, pushing for<br />

greater effort alignment.


4 - Understanding the Performance of the Long Chain and Sparse<br />

Designs in Process Flexibility<br />

Yehua Wei, Massachusetts Institute of Technology, 60<br />

Wadsworth,10B, Cambridge, MA, 02142, United States of<br />

America, y4wei@mit.edu, David Simchi-Levi<br />

This presentation develops theories to explain the effectiveness of the long chain<br />

and other sparse process flexibility designs in manufacturing systems. In the<br />

presentation, we first uncover a supermodular property for the long chain, and<br />

proceed to prove several theorems. Our results verify the effectiveness of the long<br />

chain, which has been observed empirically in both academia and industry.<br />

Moreover, the results provide new insights to how to create sparse designs.<br />

■ SA29<br />

29- North 222 A- CC<br />

Workforce Management in the Services<br />

Cluster: Workforce Management<br />

Invited Session<br />

Chair: Jennifer Ryan, Associate Professor, RPI, 110 8th Street, CII, Troy,<br />

NY, 12180, United States of America, ryanj6@rpi.edu<br />

1 - Planning for the Future - A Model of Cardiac Surgeons in<br />

Canada<br />

Sonia Vanderby, Assistant Professor, University of Saskatchewan,<br />

57 Campus Drive, Saskatoon, SK, S7N 5A9, Canada,<br />

sonia.vanderby@usask.ca, Michael Carter<br />

We present a model simulating the workforce within a single specialty at a<br />

national level which includes students training to enter the profession, providing<br />

a tool that would help to inform future resource planning. This presentation<br />

includes details of the model, developed using system dynamics modeling, and a<br />

demonstration of it using the example of cardiac surgeons in Canada, and<br />

analyzes the effect of provider motivations on system outcomes.<br />

2 - Demand Management for Optimal Workforce Planning in<br />

Professional Service Firms<br />

Vincent Hargaden, University College Dublin, School of Mech &<br />

Materials Eng, Belfield, Dublin 4, Ireland,<br />

vincent.hargaden@ucd.ie, Amir Azaron, Jennifer Ryan<br />

Our previous work has focused on characterizing and modeling the workforce<br />

planning process in professional service firms. In this, we initially assumed<br />

customer projects, i.e., demand, have fixed start dates. However, this can lead to<br />

firms not being able to fulfil all demand due to insufficient supply of<br />

workers/skills at certain points in time. We now extend our model to allow firms<br />

better manage their demand and worker/skill availability by identifying the<br />

optimum set of project start dates.<br />

3 - Dynamics of Labor, Traffic, and Sales in Retail Stores<br />

Howard Hao-Chun Chuang, PhD Candidate, Mays Business School<br />

at Texas A&M University, College Station, TX, 77843-4217,<br />

United States of America, hchuang@mays.tamu.edu, Olga<br />

Perdikaki, Rogelio Oliva<br />

We perform an empirical study that comprises multiple modeling efforts. First, we<br />

develop a response function to quantify the impact of labor and traffic on sales.<br />

Second, we propose and econometrically estimate a generic staffing heuristic.<br />

Last, we conduct counterfactual analysis in which the heuristic performs closely<br />

to the idealized optimal and outperforms existing staffing levels. Our major<br />

contribution is to quantify the benefits of planning labor based on sales as well as<br />

traffic.<br />

4 - Maintenance Policies for Multiple Machines with Technician<br />

Constraints in a Stochastic Environment<br />

Raha Akhavan-Tabatabaei, Assistant Professor, Universidad de los<br />

Andes, Cra 1 Este #19A -40, Bogota, 1111, Colombia,<br />

r.akhavan@uniandes.edu.co, Juan Sebastian Borrero Angarita<br />

We consider the problem of dynamic allocation of technicians to perform<br />

preventive maintenance (PM) operations on degrading machines in order to<br />

minimize the expected PM, repair, and waiting work in process costs. We assume<br />

Markovian processes for the degradation and load, stochastic lengths for the PM<br />

and repair operations and that each technician is able to serve only a particular<br />

set of machines. Near-optimal policies are obtained using approximate dynamic<br />

programming techniques.<br />

INFORMS Phoenix – 2012<br />

65<br />

■ SA30<br />

SA31<br />

30- North 222 B- CC<br />

Operational and Financial Decisions of the Firm<br />

Sponsor: Manufacturing & Service Oper Mgmt/iFORM<br />

Sponsored Session<br />

Chair: Jiri Chod, Boston College, 140 Commonwealth Ave,<br />

Chestnut Hill, United States of America, jiri.chod@bc.edu<br />

1 - Inventory Financing and Trade Credit<br />

Qi Wu, University of Texas at Austin, 2110 Speedway Stop B6500,<br />

Austin, TX, 78703, United States of America,<br />

qi.wu@phd.mccombs.utexas.edu, Kumar Muthuraman,<br />

Sridhar Seshari<br />

Trade credit is one of the common ways to finance inventory and is often offered<br />

via an early payment discount. In this talk, we present a model of trade credit,<br />

embedded in a stochastic inventory control problem. We compute the optimal<br />

joint inventory, cash management and trade credit decisions, based on which, we<br />

show that trade credit helps with smoothing cash flows and making better<br />

operational decisions.<br />

2 - The Impact of Budget Constraints on Flexible versus Dedicated<br />

Technology Choice<br />

Onur Boyabatli, Singapore Management University, 50 Stamford<br />

Road, Singapore, Singapore, oboyabatli@smu.edu.sg, Tiecheng<br />

Leng, Beril Toktay<br />

This paper analyzes the impact of financial constraints in a capacity investment<br />

setting. We model a two-product firm that decides on its technology choice<br />

(flexible versus dedicated) and capacity level under demand uncertainty, and the<br />

production quantities after this uncertainty is resolved. Differing from the<br />

majority of the stochastic capacity investment literature, we assume that the firm<br />

is budget-constrained both in the capacity investment and production stages.<br />

3 - The Provision and Impact of Trade Credit in Imbalanced Supply<br />

Chains: An Empirical Study<br />

Jianer Zhou, Assistant Professor, Boston College, Fulton Hall 454C,<br />

140 Commonwealth Ave., Chestnut Hill, MA, 02467,<br />

United States of America, jianer.zhou@bc.edu, Hsiao-Hui Lee<br />

Using a large dataset that links non-service U.S. suppliers with their major<br />

customers, we show trade credit to be a collaborative and competitive tool in<br />

supply chains. While suppliers with smaller market share extend more trade<br />

credit to be competitive, suppliers with weaker bargaining power extend less to<br />

mitigate financing risk. When offered at the industry-average level, trade credit<br />

increases suppliers’ sales, but when offered more aggressively, it reduces the<br />

entire supply chain sales.<br />

4 - Startegic Consumer Impact on Bankruptcy and Competition<br />

John Birge, Professor, University of Chicago, Chicago, IL,<br />

United States of America, john.birge@chicagobooth.edu,<br />

Rodney Parker, Song Alex Yang<br />

In a previous model of firm competition under the threat of one firm’s<br />

bankruptcy, we showed how that firm could use bankruptcy strategically to gain<br />

concessions from a dominant supplier. In this work, we consider the effect on the<br />

supply chain from consumers who anticipate future price discounts in the event<br />

of a bankruptcy.<br />

■ SA31<br />

31- North 222 C- CC<br />

Supply Chain Modeling under Uncertainty<br />

Cluster: Managing Disruptions in Supply Chains<br />

Invited Session<br />

Chair: Joseph Geunes, University of Florida, 303 Weil Hall, Gainesville,<br />

FL, 32611, United States of America, geunes@ise.ufl.edu<br />

1 - A Capacitated Supplier Prioritizing Asymmetric Retailers<br />

Zohar Strinka, University of Michigan, 1205 Beal Ave., Ann Arbor,<br />

MI, 48109, United States of America, zstrinka@umich.edu,<br />

Edwin Romeijn, Christopher Tang<br />

We consider a capacitated supplier and a set of asymmetric retailers. The retailers<br />

are assumed to have complete information, face newsvendor-type costs due to<br />

uncertain demand, and have a common exogenous selling price. The supplier<br />

solicits bids of a per-unit price and order quantity from each retailer, and then<br />

allocates the fixed capacity based on those bids. We show structural properties of<br />

equilibrium solutions for two retailers when the highest bid receives highest<br />

priority.


SA32<br />

2 - Planning Product Availability for an Assortment of Vertically<br />

Differentiated Products<br />

Yalcin Akcay, Koc University, Rumelifeneri Yolu, Istanbul, Turkey,<br />

yakcay@ku.edu.tr, Hari Natarajan<br />

In many industries, firms offer a variety of substitutable products that customers<br />

can choose from. Because product demands are inter-related, managers must<br />

determine inventory policies jointly. Considering the case of a verticallydifferentiated<br />

product assortment, we model and analyze the problem of<br />

determining the optimal inventory policy for a product assortment.<br />

3 - Dynamic Pricing with Strategic Customers under Price<br />

Adjustment Policy<br />

Boxiao (Beryl) Chen, University of Michigan, 1205 Beal Avenue,<br />

Ann Arbor, MI, 48109, United States of America,<br />

boxchen@umich.edu, Xiuli Chao, Hyun-Soo Ahn<br />

We study the dynamic pricing strategy of a monopolist serving heterogeneous<br />

forward-looking customers. The firm offers a price adjustment policy, which<br />

guarantees current buyers a full refund of the difference if they find a lower<br />

future price within a certain time window. We establish the existence of a<br />

subgame perfect equilibrium pricing policy and show that the firm sets different<br />

equilibrium pricing patterns in different regions of system parameters.<br />

4 - Assortment Planning in Multiple Selling Channels<br />

Yiqiang Su, Phd Candidate, University of Florida, Department of<br />

Industrial and Systems Eng, 450 Weil Hall, Gainesville, FL, 32607,<br />

United States of America, ysu1987@ufl.edu, Joseph Geunes<br />

In this research, we consider a clicks-and-mortar retailer who sells goods to endcustomers<br />

through both physical and virtual (e-commerce) channels. The retailer<br />

has limited capacity, and would like to determine the set of products to offer, both<br />

in the local and online stores to maximize its profit from sales during a single<br />

selling season. MNL and Exogenous demand models are used to capture the<br />

customer choice behaviors, and a chance-constrained two stage model is built to<br />

solve this problem.<br />

■ SA32<br />

32- North 223- CC<br />

Quality Control and Learning in Manufacturing<br />

Contributed Session<br />

Chair: Gabriel Burnett, The Boeing Company, P.O. Box 3707,<br />

MC 13-98, Seattle, WA, 98124, United States of America,<br />

gabriel.a.burnett@boeing.com<br />

1 - Changing the Paradigm for Education in Quality<br />

Thong Goh, Professor, National University of Singapore,<br />

1 Engineering Dr 2, Blk E1A #06-25, Singapore, 117576,<br />

Singapore, isegohtn@nus.edu.sg<br />

Quality education has been “customer oriented” for many decades. Some ideas<br />

and techniques have become outmoded in the modern society. It is time that<br />

some paradigm shift was made in quality management education. This needs to<br />

be realized soon if the new generation of quality practioners are to find<br />

themselves relevant.<br />

2 - A Hybrid Inspection Strategy for Rapid Deployment of<br />

Automated Inspection Technology<br />

Patrick Spicer, General Motors, General Motors R&D Center,<br />

Warren, MI, 48093, United States of America,<br />

patrick.spicer@gm.com, Mike Wincek, Jeffrey Abell, Hui Wang<br />

New manufacturing processes for advanced automotive propulsion systems (i.e.<br />

batteries or fuel cells) may not have well-developed automated inspection<br />

technologies at first. In this presentation, a hybrid inspection strategy is described<br />

that enables a manufacturer to begin with human inspection and gradually<br />

phase-in automated inspection technology until the inspection task is completely<br />

automated. This strategy has been successfully implemented in an automotive<br />

assembly plant.<br />

3 - Continuous Improvement in Cellular Manufacturing: The Case<br />

of an Electronics Manufacturer in Japan<br />

Tomoaki Shimada, Associate Professor of Operations Management,<br />

Kobe University, 2-1 Rokkodai-cho, Nada-ku, Kobe, 657-8501,<br />

Japan, shimada@b.kobe-u.ac.jp, James Ang, Hisashi Kurata<br />

This study is case-based research that analyzes continuous improvement in<br />

cellular manufacturing at an IC recorder manufacturing plant in Japan. The study<br />

provides practical insight into how to make an effort to improve the productivity<br />

of one-worker cellular production over time. The implementation results indicate<br />

that workers reduced the takt time by about 19%, and confirm that continuous<br />

improvement plays an important role in cellular manufacturing from the<br />

perspective of human dimensions.<br />

INFORMS Phoenix – 2012<br />

66<br />

4 - Investigation of Learning Curves in Production Systems<br />

Gabriel Burnett, The Boeing Company, P.O. Box 3707, MC 13-98,<br />

Seattle, WA, 98124, United States of America,<br />

gabriel.a.burnett@boeing.com, Adam Graunke<br />

We investigate the behavior of learning curves in the context of large scale<br />

production systems. Learning curves are used extensively when planning<br />

production systems. We demonstrate the implications of a variety of commonly<br />

held assumptions. We then provide an empirical study to analyze which events<br />

(i.e. rate breaks, technology insertion, derivative products, etc) create a significant<br />

departure from the global learning curve and how such events could be modeled<br />

in the future.<br />

■ SA33<br />

33- North 224 A- CC<br />

Sustainable and Responsible Operations<br />

Sponsor: Manufacturing & Service Oper Mgmt/Sustainable<br />

Operations<br />

Sponsored Session<br />

Chair: Jose Cruz, Associate Professor, University of Connecticut,<br />

School of Business, Storrs, CT, 06269, United States of America,<br />

jose.cruz@business.uconn.edu<br />

1 - Closed-loop Supply Chain with Quality Differentiation<br />

Patrick Qiang, Assistant Professor, Pennsylvania State University,<br />

Great Valley, Philadelphia, PA, United States of America,<br />

qzq10@gv.psu.edu<br />

We model the CLSC that captures consumer’s heterogeneous valuation on the<br />

remanufactured product and the new product. The model captures the interaction<br />

among various players, including manufacturers, retailers, and consumers.<br />

Numerical examples are used to provide managerial implications.<br />

2 - A Dynamic Model to Study Sustainable Business Policies in a<br />

Closed Loop Supply Chain<br />

Sudip Bhattacharjee, Associate Professor, University of<br />

Connecticut, Storrs, CT, United States of America,<br />

sbhattacharjee@business.uconn.edu, Jose Cruz<br />

The sustainability of a closed loop supply chain depends on the economic viability<br />

of all actors in the chain. We model the phenomenon analytically and create<br />

dynamic models to study key factors that impact profitability of partners in the<br />

chain. We find that product design, marketing and related actions of up-market<br />

producers significantly influence the ability of down-market recyclers to survive.<br />

We discuss environmental and revenue implications of several policy scenarios.<br />

3 - Operationalizing Sustainable Production Strategies Subject to<br />

Diminishing Resources<br />

Manuel Nunez, Associate Professor, School of Business, UConn,<br />

2100 Hillside Road Unit 1041, Storrs, CT, 06269, United States of<br />

America, mnunez@business.uconn.edu, Hsiao-Hui Lee<br />

We develop a two-stage dynamic model to analyze different sustainability<br />

strategic decisions such as starting a recycling program or developing alternative<br />

technologies to replace a diminishing resource. We investigate the impact of the<br />

parameters on the optimal decision and discuss how to operationalize the<br />

decisions in the supply chain.<br />

4 - Mitigating Global Supply Chain Risks through Corporate<br />

Social Responsibility<br />

Jose Cruz, Associate Professor, University of Connecticut,<br />

School of Business, Storrs, CT, 06269, United States of America,<br />

jose.cruz@business.uconn.edu<br />

We develop a decision model that captures supply side disruption risks, social<br />

risks, and demand side uncertainty within an integrated global supply chain and<br />

corporate social responsibility (CSR) modeling and analysis framework. We<br />

investigate the effects of CSR activities in a global supply chain and compute the<br />

equilibrium product flows, prices, and levels of social responsibility activities. The<br />

results show that CSR activities can potentially be used to mitigate global supply<br />

chain risk.


■ SA34<br />

34- North 224 B-CC<br />

Decisions in Product Development I<br />

Contributed Session<br />

Chair: Amir Sanayei, Wayne State University, 4815 Fourth St., Detroit,<br />

MI, 48202, United States of America, sanayei@wayne.edu<br />

1 - Decision Bias in Search for the Best Design Alternative<br />

Gulru Ozkan, Assistant Professor, Clemson University,<br />

101 Sirrine Hall, Clemson, SC, 29678, United States of America,<br />

gulruo@clemson.edu, David Hall, Jeremy Hutchison-Krupat,<br />

Fred Switzer<br />

In new product development, one key question is in which order to evaluate<br />

design alternatives and when to stop testing and iteration to develop a specific<br />

alternative further (search for the best alternative). Existing models analytically<br />

develop optimal search strategies for the managers while manager’s search<br />

behavior may deviate from these. Drawing from psychological literature in<br />

judgment and decision-making, such as the prospect theory, we analyze the<br />

manager’s decision making strategy.<br />

2 - Construction of a UX Component Model and its Application:<br />

A Case Study on Smart Phones<br />

Jun-yeon Heo, Pohang University of Science and Technology, Eng-<br />

Building 4-316, Hyoja-dong, Nam-gu, Pohang, Gyugbuk, Korea,<br />

Republic of, bluejy@postech.ac.kr, Min Jun Kim, Hyun-Jin Kim,<br />

Seungchul Shin, Hyo-in Ahn, Kwang-Jae Kim, Jinho Yim<br />

As the notion of User eXperience (UX) plays an important role in enhancing the<br />

competitiveness of products, UX evaluation has become an important issue in<br />

new product development. This talk presents a repository of UX components,<br />

called a UX component model, which is used for evaluating the UX of products.<br />

An application of the model is also presented using a case study on smart phones.<br />

3 - An Optimization of the Specification of BTO Technology System<br />

Yuji Sato, Mie Chukyo University, 1846 Kubo, Matsusaka, 515-<br />

8511, Japan, ysatoh@1988.jukuin.keio.ac.jp<br />

The objectives of this study were to develop a diagnosis procedure of user’s<br />

preference for a new BTO technology system, and to subsequently optimize the<br />

specification of the system. Determining the specification of a new system is<br />

complicated task, because of subjective factors entering into the evaluation of<br />

necessary and sufficient specification. By combining cost-benefit analysis and<br />

AHP, this issue was addressed. A case study was carried out to demonstrate the<br />

applicability of our approach.<br />

4 - Technology Selection: Performance, Cost and Time<br />

Considerations during Product Life Cycle<br />

Amir Sanayei, Wayne State University, 4815 Fourth St., Detroit,<br />

MI, 48202, United States of America, sanayei@wayne.edu,<br />

Leslie Monplaisir<br />

Technology selection is one of the most important and strategic decisions made in<br />

new product development process. We developed a mathematical modeling<br />

framework to select the best alternative technology in order to analyze the<br />

implications of time to market, performance and development cost. The model<br />

considers whole product life cycle in a competitive environment. It also<br />

determines optimal product launch time and the best managerial actions in order<br />

to maximize total profit.<br />

■ SA35<br />

35- North 225 A- CC<br />

Sustainability and Energy Cost<br />

Sponsor: Revenue Management & Pricing<br />

Sponsored Session<br />

Chair: Parijat Dube, IBM, TJ Watson Research Center, Hawthorne, NY,<br />

United States of America, pdube@us.ibm.com<br />

Co-Chair: Genady Ya. Grabarnik, St. John’s University, Queens, NY,<br />

United States of America, grabarng@stjohns.edu<br />

1 - The Carbon Reduction Effect and Policy Choices of Adjusting<br />

Industrial Structure<br />

Zengkai Zhang, School of Management, Xiían Jiaotong University,<br />

No.28, Xianning West Road, Shaanxi, Xi’an, China,<br />

zengkaizhang@sina.com, Ju’e Guo<br />

Reducing carbon emissions and adjusting industrial structure are China’s two<br />

strategic tasks, while adjusting industrial structure is the essential way of carbon<br />

reduction. Based on China’s SAM of 2007, this paper develops China’s dynamic<br />

CGE model to evaluate the contribution of the industrial structure adjustment in<br />

carbon reduction, and proposes policy recommendations on adjusting industrial<br />

structure.<br />

INFORMS Phoenix – 2012<br />

67<br />

SA36<br />

2 - Medical Imaging Capacity and its Impacts on Energy and<br />

Sustainability<br />

Janet Twomey, Professor, Wichita State University, Industrial and<br />

Manufacturing Engineering, 1845 Fairmount St, Wichita, KS,<br />

67206, United States of America, janet.twomey@wichita.edu<br />

The research presented here highlights a new area for energy improvement in<br />

healthcare – the energy and material use link to patient outcome decisions and<br />

alternatives.The outcomes of a study investigating the impact of medical imaging<br />

capacity decisions on energy and sustainability will be presented for a medical<br />

center and the nation’s healthcare system. Research sponsored by: NSF CMMI<br />

1037961 and NSF CMMI 0946342.<br />

3 - SUITS: A Framework for Sustainable IT Services<br />

Parijat Dube, IBM, TJ Watson Research Center, Hawthorne, NY,<br />

United States of America, pdube@us.ibm.com,<br />

Genady Ya. Grabarnik, Laura Shwartz<br />

We introduce the Sustainable IT Services (SUITS) framework to develop models<br />

for operational performance of an IT Service Provider in a global environment<br />

with carbon taxation and carbon credit trading markets. The models are used to<br />

formulate a revenue optimization problem for the IT Service Provider in this<br />

environment. The model solutions can provide guidance for designing operational<br />

level of different IT components and for creating effective strategies for trading in<br />

carbon markets.<br />

■ SA36<br />

36- North 225 B- CC<br />

New Applications of Pricing<br />

Sponsor: Revenue Management & Pricing<br />

Sponsored Session<br />

Chair: Georgia Perakis, Massachusetts Institute of Technology,<br />

Cambridge, MA, United States of America, georgiap@MIT.EDU<br />

1 - Designing Subsidies with Industry Response Dynamics:<br />

Commitment vs. Flexibility<br />

Ruben Lobel, Assistant Professor, Wharton School, Philadelphia,<br />

United States of America, rlobel@wharton.upenn.edu,<br />

Georgia Perakis, Maxime Cohen<br />

Governments use consumer incentives to promote new technologies and<br />

stimulate investments from the private sector (eg. solar panels). We model the<br />

interaction between a government and an industry player in a multi-period<br />

setting under uncertain demand. We show how the timing of decisions will affect<br />

production and subsidy levels. In particular, a flexible subsidy policy will be on<br />

average more expensive for the government than a committed long-term policy.<br />

2 - Revenue Management of Reusable Resources with<br />

Advanced Reservations<br />

Cong Shi, PhD Candidate, Massachusetts Institute of Technology,<br />

77 Massachusetts Avenue, Cambirdge, MA, 02139,<br />

United States of America, shicong@mit.edu, Retsef Levi<br />

This paper studies a class of revenue management problems in systems with<br />

reusable resources and advanced reservations. A simple control policy called the<br />

class selection policy (CSP) is proposed based on solving a knapsack-type linear<br />

program (LP). It is shown that the CSP and its variants perform provably nearoptimal<br />

in the Halfin-Whitt regimes. The analysis is based on new approaches<br />

that model the problem as loss network systems with advanced reservations.<br />

3 - A Simultaneous Approximation for Many Choice Models<br />

Vineet Goyal, Columbia University, 500W 120th St., New York,<br />

NY, United States of America, vgoyal@ieor.columbia.edu,<br />

Jose Blanchet, Guillermo Gallego<br />

Modeling customer choice probabilities is a critical problem in assortment<br />

optimization problems. Several parametric models including MNL, Nested Logit,<br />

and Mixture of MNL are widely used in practice but the selection of optimal<br />

model is not usually clear. We present a non-parametric choice model that is a<br />

simultaneous approximation for a large class of choice models. Furthermore, we<br />

give a polynomial time algorithm to compute an optimal assortment under this<br />

choice model.<br />

4 - Demand-response in the Smart Grid: A Data-driven Pricing and<br />

Inventory Optimization Approach<br />

Pavithra Harsha, Research Staff Member, IBM Research,<br />

1101 Kitchawan Rd, 34-225, Yorktown Heights, NY, 10598,<br />

United States of America, pharsha@us.ibm.com,<br />

Dharmashankar Subramanian, Ramesh Natarajan<br />

Demand response schemes based on dynamic pricing are of considerable interest<br />

in the emerging smart grid. We formulate the demand management problem as a<br />

price-sensitive newsvendor and present a novel data-driven, distribution-free<br />

approach that is based on the use of quantile and mixed quantile regression to<br />

jointly estimate the optimal generation level and pricing signals in the presence of<br />

multiple drivers of demand. We illustrate the efficacy, robustness and accuracy<br />

over alternate methods.


SA37<br />

■ SA37<br />

37- North 226 A- CC<br />

Revenue Management and Pricing in Practice<br />

Sponsor: Revenue Management & Pricing<br />

Sponsored Session<br />

Chair: Tugrul Sanli, Director, R&D, SAS Institute Inc.,<br />

SAS Campus Drive, Cary, NC, 27513, United States of America,<br />

Tugrul.Sanli@sas.com<br />

1 - Randomized Linear Programming Approach to Revenue<br />

Management<br />

Vijay Desai, Opertations Research Specialist, SAS Institute Inc.,<br />

SAS Campus Dr, Cary, NC, 27513, United States of America,<br />

VijayV.Desai@sas.com, Altan Gulcu<br />

We provide a high-level overview of our approach to RM using RLP. Following<br />

are the key features of our methodology: a) Pricing of price-dependent products.<br />

b) Handles network-level overbooking as opposed to resource-level overbooking<br />

typically found in practice. c) Allows for imposition of service level constraints. d)<br />

Computes ancillary outputs such as occupancy forecast, revenue forecast and<br />

service levels, which are useful metrics for a revenue manager.<br />

2 - Dynamic Pricing and Revenue Management<br />

Maarten Oosten, SAS Institute, World Headquarters,<br />

SAS Campus Drive, Cary, NC, 27513, United States of America,<br />

maarten.oosten@sas.com<br />

New technologies allow for pricies to be changed continuously, and optimal<br />

dynamic pricing algorithms take this freedom explicitly into account. In this<br />

presentation we explore several directions in which this can be taken.<br />

3 - Estimation of Nested Logit Models using Data from a Single<br />

Firm<br />

Jeff Newman, Research Engineer, Georgia Institute of Technology,<br />

790 Atlantic Drive, Civil Engineering, Atlanta, GA, 30332,<br />

United States of America, jeff@newman.me, Laurie Garrow,<br />

Mark Ferguson<br />

We examine identification issues for estimating parameters for discrete choice<br />

models with censored data. Most work in revenue management using such<br />

models has been focused on simple multinomial logit models, because the unique<br />

IIA property of this model makes estimating and applying parameters convenient.<br />

However, IIA is not usually consistent with actual choice behaviors. We examine<br />

the benefits and drawbacks of employing a nested logit model, which does not<br />

exhibit IIA.<br />

4 - Improving the Forecasting Accuracy of Hotel Arrivals:<br />

A New Non-homogeneous Poisson Approach<br />

Misuk Lee, IHG, 3 Ravinia Drive, Atlanta, GA, 30327,<br />

United States of America, Misuk.Lee@ihg.com<br />

Demand forecast is one of key components of hotel revenue management. This<br />

study develops a new non-homogenous Poisson process approach to short-term<br />

demand forecast. By considering seasonality and heterogeneous booking curve<br />

patterns, we find better estimates for demand processes and thus improve<br />

forecasting accuracy. We present validation results on IHG hotel data along with a<br />

comparison to other benchmark models.<br />

■ SA38<br />

38- North 226 B- CC<br />

Impact of Customer Behavior on Service<br />

Sponsor: Service Science<br />

Sponsored Session<br />

Chair: Margaret Pierson, Assistant Professor, Tuck at Dartmouth,<br />

Hanover, NH, United States of America, mpierson@hbs.edu<br />

1 - How Do Customers Respond to Service Quality Competition?<br />

Ryan Buell, Assistant Professor, Harvard Business School,<br />

Morgan Hall T37, Boston, MA, 02163, United States of America,<br />

rbuell@hbs.edu, Dennis Campbell, Frances Frei<br />

When does increased service quality competition lead to customer defection, and<br />

which customers are most likely to defect? We find that customers defect at a<br />

higher rate from the incumbent following increased service quality (price)<br />

competition when the incumbent offers high (low) quality service relative to<br />

existing competitors in a local market. We further show that it is the high quality<br />

incumbent’s most profitable customers who are the most attracted by superior<br />

quality entrants.<br />

INFORMS Phoenix – 2012<br />

68<br />

2 - Modeling Customer Behavior in Multichannel Customer<br />

Support Services: An Information Stock Approach<br />

Serguei Netessine, Professor, INSEAD, Boulevard de Constance,<br />

Fountainbleau, 77305, France, Serguei.Netessine@insead.edu,<br />

Kinshuk Jerath, Anuj Kumar<br />

We analyze multichannel customer support environment of a health insurance<br />

firm in the US. We build a structural probability model to understand the<br />

customers’ query arrival and channel choice processes. Our estimates suggest the<br />

telephone channel in our setting on average provides 20 times more information<br />

than the Web channel and that the Web on average provides information need<br />

instead of information gain – Web in our setting seems to confuse customers.<br />

3 - Customer Response to Short-Term Price Fluctuations<br />

Margaret Pierson, Assistant Professor, Tuck at Dartmouth,<br />

Hanover, NH, United States of America, mpierson@hbs.edu<br />

Transactions at 15 gasoline stations in Massachusetts over two years are used to<br />

estimate consumer elasticity with respect to price on a transaction basis. A<br />

significant proportion of the observed transactions display high sensitivity to<br />

price. This customer behavior results in congestion at pumps during high prices, a<br />

counterintuitive result which constrains stations’ price choices in practice.<br />

■ SA39<br />

39- North 226 C- CC<br />

Service Scripting and Value Co-Creation<br />

Sponsor: Service Science<br />

Sponsored Session<br />

Chair: Gregory Heim, Associate Professor, Mays Business School at<br />

Texas A&M University, 320 Wehner Building, 4217 TAMU, College<br />

Station, TX, 77843-4217, United States of America,<br />

gheim@mays.tamu.edu<br />

1 - Scripting and Improvisation in Service Environments<br />

Enrico Secchi, University of Victoria, Peter B. Gustavson School of<br />

Business, Business & Economics Building Room 254, Victoria, BC,<br />

V8P 5C2, Canada, esecchi@clemson.edu, Rohit Verma, Aleda Roth<br />

Using the insights of the research on scripting and organizational improvisation,<br />

we develop an econometric model of the impact of different degrees of scripting<br />

and improvisation on services financial outcomes. We test our model using survey<br />

data and self reported financial performance from the hospitality industry.<br />

2 - Co-Creation of Value for IT-Enabled Services:<br />

A Case of Geocaching<br />

Tuure Tuunanen, University of Oulu, Department of Information<br />

Processing Science, P.O. 3000, 90014 University of Oulu, Finland,<br />

tuure@tuunanen.fi, Tero Vartiainen<br />

This study uses laddering interviews to explore how value is co-created for ITenabled<br />

services, more precisely geocaching. The results reveal that geocaching is<br />

distinctly hedonic in nature. The results also demonstrate how the consumer<br />

information systems framework can be applied for understanding which factors<br />

influence value co-creation for IT-enabled services.<br />

3 - Analysis of Role of Service Variety and Real Options in Resort<br />

Timeshare Service Value<br />

Gregory Heim, Associate Professor, Mays Business School at Texas<br />

A&M University, 320 Wehner Building, 4217 TAMU,<br />

College Station, TX, 77843-4217, United States of America,<br />

gheim@mays.tamu.edu<br />

Although a major class of hospitality/travel experience service, little empirical<br />

research has examined timeshares or other fractional hospitality services. This<br />

paper examines whether service variety, in terms of breadth of vacation service<br />

experiences, or real options more strongly affect the perceived quality, valuation,<br />

and ownership of resort hotel timeshare services. We analyze hypotheses using<br />

both cross-sectional and longitudinal data sets.


■ SA40<br />

40- North 227 A- CC<br />

Dynamic Models for Sustainable Energy Policy<br />

Analysis<br />

Sponsor: Energy, Natural Res & the Environment/Energy<br />

Sponsored Session<br />

Chair: Pedro Linares, Comillas P. University, Alberto Aguilera 25,<br />

Madrid, 28015, Spain, pedro.linares@upcomillas.es<br />

1 - Canadian Energy Supply and Demand with ENERGY 2020:<br />

Scenarios and Sensitivity Cases<br />

Matthew Hansen, Market Analyst, National Energy Board,<br />

444-7th Ave., SW, Calgary, AB, T3C 0T1, Canada,<br />

Matthew.Hansen@neb-one.gc.ca<br />

The National Energy Board periodically releases long-term projections of<br />

Canadian energy supply and demand as part of its Energy Futures series. Since<br />

2007, the ENERGY 2020 model has been central to this analysis. This<br />

presentation will describe how the National Energy Board uses ENERGY 2020 to<br />

create the scenarios and sensitivity cases featured in the Energy Futures reports.<br />

2 - Multi-stage Stochastic Optimization of an Energy System Model<br />

Joseph DeCarolis, Assistant Professor, North Carolina State<br />

University, 2501 Stinson Drive, Campus Box 7908, Raleigh, NC,<br />

27695, United States of America, jdecarolis@ncsu.edu,<br />

Kevin Hunter, Sarat Sreepathi<br />

We perform multi-stage stochastic optimization of a simplified energy system. The<br />

system consists of roughly 30 technologies used to supply primary energy<br />

resources, refine petroleum, generate electricity, and serve end use demands. The<br />

model incorporates crude oil, natural gas, and coal prices as stochastic parameters.<br />

Results indicate that the energy system requires little recourse as uncertainty is<br />

revealed over a multi-decadal time horizon.<br />

3 - Incorporating Endogenous Demand into Capacity Expansion<br />

Models for Developing Countries<br />

Rhonda Jordan, PhD Candidate, Massachusetts Institute of<br />

Technology, 143 Albany Street, #201A, Cambridge, MA, 02139,<br />

United States of America, rjordan@mit.edu<br />

Using a novel combination of approximate dynamic programming, system<br />

dynamics and linear programming, this research develops a power system<br />

capacity expansion model that incorporates both the technical details of power<br />

grid operation and the salient features of electricity demand in developing<br />

countries. Unlike traditional planning models, demand is represented<br />

endogenously. The capacity expansion strategies identified in this research are<br />

compared against that of more traditional approaches.<br />

4 - A Dynamic Model for Sustainable Energy Policy Making in<br />

Spain<br />

Alvaro Lopez-Peña, Comillas P. University, IIT,<br />

Santa Cruz de Marcenado 26, Madrid, 28015, Spain,<br />

alvaro.lopezpena@iit.upcomillas.es, Pedro Linares,<br />

Ignacio Pérez-Arriaga<br />

Today, there is an important need for sound sustainable energy policies. For<br />

assessing them, mathematical models are needed, which allow to represent<br />

energy systems’ evolution over the long term under different policy assumptions<br />

(trajectories). We present a dynamic model applied to Spain, which aims at<br />

representing realistic trajectories. By realistic, we mean that it takes into account<br />

important aspects of energy systems such as imperfect markets, investor’s myopia<br />

and risk aversion.<br />

■ SA41<br />

41- North 227 B- CC<br />

Models in Energy Investment<br />

Contributed Session<br />

Chair: Carlos Ruiz, École Centrale Paris and SupÈlec, Grande Voie des<br />

Vignes, Ch‚tenay-Malabry, 92295, France, carlosruizmora@gmail.com<br />

1 - On the Value of Improved Models for the Electricity Sector<br />

Alberto Lamadrid, Graduate Student, Cornell University,<br />

419 Warren Hall, Ithaca, NY, 14850, United States of America,<br />

ajl259@cornell.edu, Tim Mount, Ray Zimmerman, Robert Thomas<br />

This paper measures the value of the stochastic solution for a system with high<br />

penetration of renewable energy sources, contrasting it to a deterministic<br />

formulation with fixed reserves, as used by System Operators (SO). The<br />

performance analysis focuses on measures of the system economic costs. Our<br />

model has a SO minimizing the expected cost of providing both energy and<br />

ancillary services with a security constrained OPF. Uncertainty is reproduced<br />

using a Markovian transition probability matrix.<br />

INFORMS Phoenix – 2012<br />

69<br />

SA42<br />

2 - Mathematical Model for Planning Investments in Energy<br />

Sources for Argentina<br />

Julio Rolando Flores, Becario, INGAR, Eva Peron 2660,<br />

Santa Fe, SF, 3000, Argentina, jflores@santafe-conicet.gov.ar,<br />

Jorge M. Montagna, Aldo Vecchietti<br />

This paper presents a mathematical programming model for planning investment<br />

in energy sources for Argentina. The model considers the use of renewable and<br />

not renewable sources and uncertainties in demands, costs, and the amount of<br />

reserves of fossil fuels. The objective function of is to minimize the investment<br />

and operation costs of the energy supply. The results provide the visualization of<br />

the investments made: time periods in and their amounts and also how the<br />

energy matrix is affected.<br />

3 - Biomass Based Energy Logistics System<br />

Wooseung Jang, Professor, University of Missouri, E3437 Lafferre<br />

Hall, Columbia, MO, 65211, United States of America,<br />

jangw@missouri.edu, Rana Afzali Baghdadabadi, Cerry Klein,<br />

James Noble, Zhongwei Yu, Kurt Ehlers<br />

We develop an optimization model supporting the multi-stage decision making of<br />

infrastructure investment and operation of the biomass logistics system. In<br />

addition, we build a database for biomass availability, cost and other supply<br />

information. Our work is applied to the biomass power plants scheduled to<br />

operate in Missouri.<br />

4 - Transmission Expansion Planning using an AC Model:<br />

Formulations and Possible Relaxations<br />

Hui Zhang, Research Associate, Arizona State University, 1223 S<br />

Dorsey Ln, Apt 101, Tempe, AZ, 85281, United States of America,<br />

hui.zhang@asu.edu, Hans Mittelmann, Vijay Vittal, Gerald Heydt<br />

Starting with two MINLP models, this paper explores the possibility of applying<br />

AC-based models to the transmission expansion planning (TEP) problem. Two<br />

NLP relaxation models are then proposed by relaxing the binary decision<br />

variables. A reformulation-linearization-technique (RLT) based relaxation model<br />

is also presented in the paper. The simulation results show that by using proper<br />

reformulations or relaxations, it is possible to apply the AC models to TEP<br />

problems and obtain a good solution.<br />

5 - Robust Reliability Optimization by System Design and<br />

Components Allocation<br />

Carlos Ruiz, École Centrale Paris and Supèlec,<br />

Grande Voie des Vignes, Châtenay-Malabry, 92295, France,<br />

carlosruizmora@gmail.com, Rodrigo Mena, Enrico Zio, Yanfu Li<br />

We address the problem of power system design and components allocation<br />

under multiple sources of uncertainty. We consider a set of fixed buses with<br />

uncertain demand loads and we seek to identify the electrical lines and generating<br />

units that should be installed in order to minimize the system operational cost<br />

and maximize its reliability. The optimization relies on a bilevel model that is<br />

robust against generation capacity variability as well as unit and line failures.<br />

■ SA42<br />

42- North 227 C- CC<br />

Strategic Issues in Freight Transportation<br />

Contributed Session<br />

Chair: Zhougeng Lin, PhD Student, University of Portsmouth, Lion<br />

Gate Building, Lion Terrace, Portsmouth, PO1 3HF, United Kingdom,<br />

Zhougeng.Lin@Port.Ac,Uk<br />

1 - Mixed Fleet Dispatching Optimization in Truckload<br />

Transportation<br />

Hector A. Vergara, Visiting Assistant Professor, Oregon State<br />

University, 204 Rogers Hall, Corvallis, OR, 97331,<br />

United States of America, vergarah@onid.orst.edu, Sarah Root<br />

In a mixed fleet dispatching system for truckload transportation some truckloads<br />

are sent direct point-to-point while others are routed through a network of relay<br />

points where drivers are exchanged allowing them to return home more<br />

frequently. We propose a mathematical formulation for strategic relay network<br />

design and dispatch mode selection that incorporates several operational<br />

constraints within the variable definition. Computational results are presented<br />

along with areas for future research.<br />

2 - Freight Network Design with Pricing and Economies of Scale<br />

Panagiotis Ypsilantis, PhD Candidate, RSM, Erasmus University,<br />

Burgemeester Oudlaan 50, Rotterdam, Netherlands,<br />

pypsilantis@rsm.nl, Rob Zuidwijk<br />

The freight service network design in a strategic level is formulated as a bi-level<br />

mathematical program; the pricing, design and economies of scale are considered<br />

in a competitive environment. The net revenues of a TOC that operates barge and<br />

train connections to inland terminals according to the extended gate concept are<br />

maximized while the total costs faced by the users of the network are minimized.<br />

A solution approach for this problem and some numerical results are presented<br />

and discussed.


SA43<br />

3 - Freight Origin-destination Estimation using Bayesian Networks<br />

Based on Multiple Data Sources<br />

Yinyi Ma, Erasmus University Rotterdam, Burg. Oudlaan 50,<br />

Rotterdam, Netherlands, yma@rsm.nl, Roelof Kuik,<br />

Henk van Zuylen<br />

Freight origin-destination (OD) estimation becomes increasingly important.<br />

Traditional general traffic OD estimation methods based on loop detectors have<br />

the under-specification problem. This paper investigates a Bayesian Networks<br />

approach for estimating freight OD-matrices by Markov-chain-Monte-Carlo<br />

methods, thereby mitigating under-determinacy by exploiting proportionallycontributing<br />

multiple data sources, such as camera, Bluetooth and<br />

Weigh-in-Motion.<br />

4 - Simulation and Multi-objective Optimization Combining<br />

Framework for Container Terminal Optimization<br />

Zhougeng Lin, PhD Student, University of Portsmouth, Lion Gate<br />

Building, Lion Terrace, Portsmouth, PO1 3HF, United Kingdom,<br />

Zhougeng.Lin@Port.Ac,Uk, Dylan Jones<br />

This presentation proposes a combining framework to integrate simulation and<br />

multi-objective optimization(MOO) for better description of dynamic real-world<br />

systems in low cost and reasonable computational time. A case study on container<br />

terminal equipment optimization is discussed to demonstrate its applications.<br />

Results are compared by post-MOO structure and integrated MOO structure.<br />

■ SA43<br />

43- North 228 A- CC<br />

RAS Student Paper Award<br />

Sponsor: Railway Applications<br />

Sponsored Session<br />

Chair: Juan Morales, BNSF Railway, TX, United States of America,<br />

Juan.Morales@BNSF.com<br />

1 - RAS Student Paper Award<br />

Juan Morales, BNSF Railway, TX, United States of America,<br />

Juan.Morales@BNSF.com<br />

Finalists of the 2012 RAS Student Paper Award will present their work in this<br />

session. Finalists were not determined prior to the abstract submission deadline of<br />

the printed programs.<br />

■ SA44<br />

44- North 228 B- CC<br />

Supply Chain Structures and Incentives<br />

Contributed Session<br />

Chair: Suleyman Demirel, PhD Candidate, University of Michigan,<br />

701 Tappan St., Ann Arbor, MI, 48109, United States of America,<br />

sdemirel@umich.edu<br />

1 - Agile Supply Chain Building via Semantic Supplier Search<br />

Jaehun Lee, POSTECH, 312, Eng4, POSTECH, Hyoja, Pohang,<br />

Korea, Republic of, jaehun_lee@postech.ac.kr, Taejong Yoo,<br />

Hyunbo Cho, Bohyun Kim<br />

The goal of a supply chain in manufacturing domain is to guarantee that the right<br />

amount of the right product is in the right place at the right time. To accomplish<br />

this, an agile supply chain formation is critical. We propose a semantic<br />

manufacturing supplier discovery framework that structuralizes buyer’s demand<br />

requirements and supplier’s capability information to assist in building such a<br />

supply chain.<br />

2 - Supply Network Structure and Firm Innovation:<br />

An Empirical Investigation<br />

Marcus Bellamy, Georgia Institute of Technology, 800 West<br />

Peachtree ST NW, Atlanta, GA, 30308, United States of America,<br />

marcus.bellamy@gatech.edu, Soumen Ghosh, Manpreet Hora<br />

We investigate the impact of supply network structure on firm innovation. Using<br />

a network-analytic lens, we develop and test our hypotheses linking firm level<br />

network properties and innovation. Our analysis considers how firm innovation is<br />

affected through the extended network it shares between each entity in the<br />

supply network.<br />

INFORMS Phoenix – 2012<br />

70<br />

3 - The Effect of a Temporary Product Distribution Channel on<br />

Supply Chain Performance<br />

Moutaz Khouja, Professor, University of North Carolina-Charlotte,<br />

9201 University City Blvd., Charlotte, NC, 28223,<br />

United States of America, mjkhouja@uncc.edu<br />

We analyze a supply chain of a manufacturer and two retailers. The first retailer<br />

always stocks the product. The second retailer is a deal-of-the day (DOTD) retailer<br />

who sells the product for a short time of few days at a discount. The DOTD<br />

retailer sells the product at a discount due to a price discount she gets for ordering<br />

a large quantity. We identify the discounted wholesale price and the discount<br />

order quantity. We find that he temporary channel can increase the profit of the<br />

manufacturer.<br />

4 - Revisiting Interorganizational Trust: Is More Always Better or<br />

Could More Be Worse?<br />

Veronica H. Villena, Assistant Professor, Pennsylvania State<br />

University, 410 Business Building, University Park, State College,<br />

PA, 16802, United States of America, vhv1@psu.edu,<br />

Thomas Choi, Elena Revilla<br />

We conduct a more comprehensive examination of trust by considering both its<br />

positive and negative effects and by investigating how they function differently<br />

under different types of uncertainties.We use data from a sample of 133 buyersupplier<br />

relationships. The results suggest that the negative effects of trust become<br />

more notable when there is high behavioral uncertainty between buyers and<br />

suppliers and less evident when there is high environmental uncertainty for<br />

buyers.<br />

■ SA45<br />

45- North 229 A- CC<br />

JFIG Paper Competition I<br />

Sponsor: Junior Faculty Interest Group<br />

Sponsored Session<br />

Chair: Esra Buyuktahtakin, Assistant Professor, Wichita State<br />

University, IME Department, Wichita, KS, United States of America,<br />

esra.b@wichita.edu<br />

1 - JFIG Paper Competition<br />

Esra Buyuktahtakin, Assistant Professor, Wichita State University,<br />

IME Department, Wichita, KS, United States of America,<br />

esra.b@wichita.edu<br />

Papers are submitted for this year’s JFIG paper competition, and each one is<br />

evaluated based on the importance of the topic, appropriateness of the research<br />

approach, and the significance of research contribution. In this session, finalistsselected<br />

in two rounds of review, will present their papers. For the selected<br />

finalists and the abstracts of the selected papers, please refer to the online<br />

program.<br />

■ SA46<br />

46- North 229 B- CC<br />

Organizational and Industry Renewal (I): Innovation,<br />

Industry Context, and Population-Level Learning<br />

Sponsor: Organization Science<br />

Sponsored Session<br />

Chair: Andreas Schwab, , Associate Professor, Iowa State University,<br />

3315 Gerdin, Ames, IA, 50011, United States of America,<br />

aschwab@iastate.edu<br />

1 - Exploring Organizational Identity and Organizational Design in<br />

Technological Transitions<br />

Mary Tripsas, Associate Professor, Harvard Business School,<br />

219 Rock Center, Soldiers Field Rd, Boston, MA, 02163,<br />

United States of America, mtripsas@hbs.edu<br />

Innovation research suggests that a separate new technology unit with its own<br />

identity increases the odds of a successful technological transformation. Identity<br />

research, however, has shown that multiple identities can be harmful, posing a<br />

dilemma. Through a comparison of FujiFilm and Polaroid’s reactions to digital<br />

imaging, we propose that establishing a separate new technology unit can cause<br />

dormant identity conflicts to surface, and reconciling those conflicts is critical to<br />

success.


2 - Ties that Bind? The Differential Ability of de alio and de novo<br />

Firms to Leverage External Relations<br />

Glenn Hoetker, Associate Professor, W.P. Carey School of Business,<br />

Arizona State University, P.O. Box 874006, Tempe, AZ, 85287-<br />

4006, United States of America, Glenn.Hoetker@asu.edu, Pao-Lien<br />

Chen, Rajshree Agarwal<br />

External relationships may help a firm learn about disruptive technological<br />

changes, but may also impede the firm’s adopting new technologies. We examine<br />

the impact of a firm’s pre-entry experience on its dynamic capability to maximize<br />

learning and minimize inertia created by ties to suppliers. We find that de alio<br />

firms better harness information available through a larger network of suppliers<br />

than de novo firms, but are equally constrained by the length of prior<br />

relationships.<br />

3 - Whose Side Are You On? The Role of States in Influencing<br />

Healthcare Service Delivery Innovations<br />

Scott Feyereisen, 4666 East Camino Rosa, Tucson, AZ, 85718,<br />

United States of America, feyerbal@email.arizona.edu,<br />

Joseph Broschak<br />

We explore why all U.S. states would not adopt a seemingly rational, efficient and<br />

cost-reducing policy innovation. Using institutional and resource dependence<br />

theory, we develop and test hypotheses related to a state’s propensity to adopt<br />

contested healthcare legislation. Professional power and heterogeneity, state<br />

resources and prior state adoptions are hypothesized to affect a state’s likelihood<br />

of adopting a policy change. We test our predictions using data on anesthesia<br />

policy adoptions.<br />

4 - Population-Level Learning: Industry-Level Variability of<br />

Learning Outcomes from Innovations<br />

Andreas Schwab, Associate Professor, Iowa State University,<br />

3315 Gerdin, Ames, IA, 50011, United States of America,<br />

aschwab@iastate.edu, Jay O’Toole, Anne Miner<br />

This study investigates industry-level variability in learning outcomes following<br />

the implementation of an innovation. We challenge the intuition that early<br />

periods are marked by more variation than later periods. Contingency factors that<br />

shape variability include varied imitation rules, deliberate innovation, and<br />

interactions across innovation features and levels of learning. We test hypotheses<br />

using historic data on the farm-system, an administrative innovation in baseball<br />

industry.<br />

■ SA47<br />

47- North 230- CC<br />

New Advances in Traffic Operations<br />

Sponsor: Transportation Science & Logistics/ Intelligent<br />

Transportation Systems (ITS)<br />

Sponsored Session<br />

Chair: Carolina Osorio, Assistant Professor, Massachusetts Institute of<br />

Technology, Room 1-232, 77 Massachusetts Avenue, Cambridge, MA,<br />

02139, United States of America, osorioc@mit.edu<br />

1 - Combining Metamodel Techniques and Bayesian Selection<br />

Procedures to Derive Computationally Efficient Traffic<br />

Management Algorithms<br />

Hoda Bidkhori, Massachusetts Institute of Technology,<br />

77 Massachusetts Ave., Room 1-172, Cambridge, MA, 02139,<br />

United States of America, bidkhori@mit.edu, Carolina Osorio<br />

This talk introduces simulation-based optimization (SO) methods to address the<br />

problems in Traffic Management. It proposes an SO technique that uses<br />

metamodel information together with a Bayesian framework, where the<br />

parameters of the prior distributions are estimated based on probabilistic<br />

metamodel information. In order to derive an SO algorithm that achieves a good<br />

trade-off between detail, realism and computational efficiency, the metamodel<br />

combines information from a highresolution traffic simulator with information<br />

from a lower-resolution yet computationally efficient analytical queueing<br />

network model. We use this approach to address an urban traffic management<br />

problem using a detailed microscopic traffic simulator of the Swiss city of<br />

Lausanne.<br />

2 - Application of Online DTA Framework for Weather-related<br />

Traffic Management<br />

Hani S. Mahmassani, Northwestern University, Evanston, IL,<br />

60208, United States of America, masmah@u.northwestern.edu,<br />

Ying Chen, Jiwon Kim, Lan Jiang<br />

Weather-related traffic management through variable message signs, speed<br />

control and active demand management is an important application for predictive<br />

traffic estimation and prediction based on online DTA deployments. A framework<br />

and associated methodology is presented and demonstrated through several<br />

applications.<br />

INFORMS Phoenix – 2012<br />

71<br />

SA48<br />

3 - On Observable Chaotic Maps for Transportation<br />

Queueing Analysis<br />

Joseph Y.J. Chow, Assistant Professor, Ryerson University,<br />

350 Victoria Street, Toronto, ON, M5B 2K3, Canada,<br />

joseph.chow@ryerson.ca<br />

Chaotic mapping can capture a number of characteristics in queues: transient<br />

behavior, intermittency, steady state, and complex distributions. The proposed<br />

queueing model uses chaotic mapping of inter-arrival times to generate arrivals so<br />

that parameters can be calibrated with observable data. A sample mapping based<br />

on the logistic map is presented and shown to be ergodic. A joint parameter and<br />

state estimation algorithm is presented. The advantages are studied with two<br />

connected nodes.<br />

■ SA48<br />

48- North 231 A- CC<br />

Maritime Transportation<br />

Contributed Session<br />

Chair: Dimitri Papageorgiou, PhD Candidate, Georgia Tech,<br />

765 Ferst Ave, Atlanta, GA, 30332, United States of America,<br />

djpapag@gatech.edu<br />

1 - Evaluation of Intermodal Marine Container Terminal Gate<br />

Strategies via Simulation<br />

Jeffery Karafa, University of Memphis, 104 Engineering Science<br />

Bldg, 3815 Centr, 3815 Central Avenue, Memphis, TN, 38152,<br />

United States of America, jefferykarafa@yahoo.com, Mihalis Golias<br />

We present the development of a traffic simulation model to measure the impact<br />

of gate strategies on congestion levels at intermodal marine container terminal<br />

gates. The traffic model is used to quantify both travel time and delay and<br />

emission levels at the terminal gates before and after gate strategies have been<br />

implemented.<br />

2 - Equilibrium Model for Analysis on Opening and Improving<br />

Transportation Routes<br />

Kazuhiko Ishiguro, Kobe University, 5-1-1, Fukaeminami,<br />

Higashinada, Kobe, 658-0022, Japan,<br />

ishiguro@maritime.kobe-u.ac.jp, Pitu Mirchandani<br />

Transport cost reduction will trigger new transport demand. This study develops<br />

international trade model taking account of ocean carriers’ behavior based on<br />

multi-regional computable general equilibrium framework. Trade amount is<br />

formulated as the demand of goods produced in other region. The model is<br />

applied to opening and improving transportation routes and the impacts on trade<br />

are discussed.<br />

3 - Quickly Finding Good Solutions to Large-scale Maritime<br />

Inventory Routing Problems<br />

Dimitri Papageorgiou, PhD Candidate, Georgia Tech,<br />

765 Ferst Ave., Atlanta, GA, 30332, United States of America,<br />

djpapag@gatech.edu<br />

We describe aggregation and decomposition techniques for quickly finding good<br />

solutions to large-scale maritime inventory routing problems. Solving the LP<br />

relaxation of the “standard” mixed-integer programming formulation of these<br />

problems can require hours to solve, assuming they can be loaded into memory.<br />

Meanwhile, our goal is to find high quality solutions in minutes. We present<br />

methods that accomplish this objective and compare them to two benchmarks<br />

that have been used in the literature.


SA49<br />

■ SA49<br />

49- North 231 B- CC<br />

Joint Session TSL/SPPSN: Geographic, Building and<br />

Pedestrian Evacuation Modeling<br />

Sponsor: Transportation Science & Logistics & Public Programs,<br />

Service and Needs<br />

Sponsored Session<br />

Chair: Douglas Bish, Assistant Professor, Virginia Tech, Department of<br />

Industrial and Systems Eng., 250 Durham Hall, Blacksburg, VA, 24061-<br />

0118, United States of America, drb1@vt.edu<br />

1 - Simulating Pedestrian Evacuation from Large Events<br />

Pitu Mirchandani, Arizona State University, 699 South Mill<br />

Avenue, Tempe, AZ, 85287, United States of America,<br />

pitu@asu.edu, Ning Wang, Zhuoyang Zhou<br />

At the end of a large event, attendees move from their seats to an exit, and then<br />

walk over to the vehicle, which they subsequently use to reach their ultimate<br />

destination. This paper develops a simulation model, using the pedestrian feature<br />

in VISSIM, to evaluate delays in normal and no-notice evacuation scenarios.<br />

Evacuation strategies are studied to make total evacuation time to leave the<br />

building or stadium and reach respective destinations as small as possible.<br />

2 - Pedestrian Route Choice Modeling in a Changing<br />

Physical Environment<br />

Lei Feng, University of Maryland, College Park, MD,<br />

United States of America, lfeng@umd.edu, Elise Miller-Hooks<br />

The selection of routes in a congested pedestrian network in which the physical<br />

environment is changing is explored. Models of route choice behavior in this<br />

environment are developed. The evolving physical conditions, improving<br />

pedestrian situational awareness, responsively changing goals, and individual and<br />

collective responses are explicitly recognized in these models of route choice.<br />

3 - Fleet Management and Equity Measures in Evacuation<br />

Transportation Planning for Multiple Hospitals<br />

Esra Agca, PhD Student, Virginia Tech, Department of Industrial<br />

and Systems Eng., 250 Durham Hall, Blacksburg, VA, 24061,<br />

United States of America, esra.vt@gmail.com, Douglas Bish,<br />

Roger Glick<br />

A coordinated response is required for to effectively evacuate multiple hospitals<br />

due to a regional threat (e.g., a hurricane). Organizing the evacuation response<br />

can be more complicated when it involves more than one hospital system (groups<br />

of hospitals under the same management). In this research we study optimal<br />

evacuation plans for multiple hospitals, including full centralized control, and the<br />

study of equity issues at various levels, including at the hospital system level.<br />

4 - Optimizing a Large Scale Evacuation Plan for Tucson, AZ<br />

Neema Nassir, Graduate Research Assistant, University of Arizona,<br />

Department of Civil Engineering and Engineering Mechanics,<br />

1209 E. Second Street, Tucson, AZ, 85721-0072,<br />

United States of America, neeman@email.arizona.edu,<br />

Hong Zheng, Mark Hickman, Yi-Chang Chiu<br />

Every year hundreds of chlorine tankers pass through downtown Tucson. This<br />

study aims to optimize evacuation under a hypothetical tanker spill. Current gas<br />

dispersion models indicate that such a spill may lead to deadly consequences for<br />

many persons in this large urban area. In our evacuation model, the objective is<br />

to minimize the total exposure of the citizens to the poisonous gas, taking into<br />

account the different concentration levels of gas over the space.<br />

■ SA50<br />

50- North 231 C- CC<br />

Military Applications<br />

Sponsor: Military Applications<br />

Sponsored Session<br />

Chair: Sung-Pil Kim, Yonsei University / R.O.K Navy, Yonseiro 50,<br />

Seoul, Korea, Republic of, senseksp@gmail.com<br />

1 - Modeling Multi-echelon Inventories for Naval Repair Parts in<br />

the ROK Navy<br />

Sung-Pil Kim, Yonsei University/R.O.K Navy, Yonseiro 50, Seoul,<br />

Korea, Republic of, senseksp@gmail.com<br />

In comparison to the rapid modernization of defense equipment, government<br />

resources are restricted, necessitating an efficient solution for managing all<br />

national resources, including naval repair parts.This paper investigates the<br />

modeling of efficient multi-echelon inventory management of naval repair parts<br />

in the ROK Navy.<br />

INFORMS Phoenix – 2012<br />

72<br />

2 - Once More: Putting the “O” Back into Military<br />

Operations Research<br />

George Kuhn, LMI, 2000 Corporate Ridge, McLean, VA, 22102,<br />

United States of America, GKuhn@lmi.org<br />

Research results are described for two core military management topics:<br />

estimating Forces personnel attrition (casualty estimation), and forecasting unitlevel<br />

requirements for aircraft (helicopter) spare parts. While being clearly<br />

different planning domains on one level, at another level the difficulties that have<br />

long burdened estimating/forecasting such requirements share a common root:<br />

unless data collection and analysis are grounded on capturing and reflecting the<br />

inherent character of military operations, estimates/forecasts will inevitably fail to<br />

describe requirements accurately. Evidence is presented that, properly grounded<br />

on describing patterns of military operations, quantitative analysis can project<br />

requirements accuratelyóand these results differ markedly from standard<br />

portrayals that rely on conceptual and quantitative conventions incongruent with<br />

the underlying character of military operations.<br />

■ SA51<br />

51- North 232 A- CC<br />

Disaster Relief Planning and Operations<br />

Sponsor: Military Applications<br />

Sponsored Session<br />

Chair: Xiaofeng Nie, Assistant Professor, Nanyang Technological<br />

University, 50 Nanyang Avenue, Singapore, 639798, Singapore,<br />

xiaofengnie@ntu.edu.sg<br />

1 - Prepositioning of Supplies in Preparation for a Hurricane with<br />

Forecast Information Updates<br />

Rajan Batta, University at Buffalo (SUNY), Dept. of Industrial &<br />

Systems Engg, Buffalo, NY, 14260, United States of America,<br />

batta@buffalo.edu, Gina Galindo<br />

It is possible to use prediction models to obtain periodic forecasts about a<br />

hurricane’s main characteristics such as its path, wind force and time of landfall.<br />

Using this information we present a dynamic model for prepositioning supplies in<br />

such a setting. Our model has two distinguishing features: possible destruction of<br />

supply points during the disaster event, and the use of forecast information<br />

updates in order to strategically modify and improve the prepositioned quantities<br />

and locations.<br />

2 - A Stochastic Programming Model for Casualty Response<br />

Planning during Catastrophic Health Events<br />

Aakil Caunhye, PhD Student, Nanyang Technological University,<br />

758, Choa Chu Kang North 5, Singapore, 680758, Singapore,<br />

M090028@e.ntu.edu.sg, Xiaofeng Nie<br />

Catastrophic health events are natural or man-made incidents that create<br />

casualties in numbers that overwhelm healthcare response capabilities. We<br />

construct a three-stage stochastic programming model to locate alternative care<br />

facilities and transport casualties in response to such events. We also propose an<br />

L-shaped cut algorithm, to generate good solutions fast. We analyse the model<br />

and algorithm in the case of a high-impact earthquake in a subregion of San<br />

Bernardino, California.<br />

3 - Identifying the Role and Impact of Social Media in Evacuation<br />

Justin Yates, Assistant Professor, Texas A&M University, 4079 ETB,<br />

3131 TAMU, College Station, TX, 77843-3131, United States of<br />

America, jtyates@tamu.edu<br />

The next generation of evacuation planning and emergency response strategies<br />

needs to be built on the context of real-time information dissemination.<br />

The goal of this research is to build a new set of evacuation models capable of<br />

incorporating spatio-temporal data on extremely large scales and supported by<br />

new behavioral paradigms predicated on the use of social media. We discuss our<br />

initial efforts and insights in this presentation.<br />

4 - Heuristic Methods for Hazard Zone Determinations<br />

Ed Pohl, University of Arkansas, Department of Industrial<br />

Engineering, Fayetteville, AR, United States of America,<br />

epohl@uark.edu, Manuel D. Rossetti<br />

To better examine the use of optimization in emergency planning this research<br />

investigates the determination of hazard zones within a geographic area. A hazard<br />

zone is an area corresponding to a worst-case evacuation scenario and is a<br />

potential vulnerability that should be addressed by risk mitigation strategies. The<br />

research compares two heuristic approaches to determining hazard zones based<br />

on population and road connectivity within a spatial network.


■ SA52<br />

52- North 232 B- CC<br />

Electricity Markets: Game-theory Based Models for<br />

Strategic Planning<br />

Sponsor: Energy, Natural Res & the Environment/Energy<br />

Sponsored Session<br />

Chair: Efraim Centeno, Institute for Research in Technology - ICAI,<br />

Comillas Pontifical University, Alberto Aguilera 25, Madrid, 28015,<br />

Spain, Efraim.Centeno@upcomillas.es<br />

1 - Study of Strategic Behavior Impact in the Spot Market on<br />

Capacity Expansion using a Linearised EPEC<br />

Efraim Centeno, Institute for Research in Technology-ICAI,<br />

Comillas Pontifical University, Alberto Aguilera 25, Madrid, 28015,<br />

Spain, Efraim.Centeno@upcomillas.es, Sonja Wogrin,<br />

Julian Barquin<br />

Capacity expansion decisions are represented using a bilevel approach (EPEC). In<br />

the upper level the competing generation companies maximize their individual<br />

profits, while the lower level represents the spot markets using a conjectured<br />

price-response approach. This model is linearised and solved to show the solution<br />

variation with respect to the level of competence in the spot market and that the<br />

market equilibrium can have multiple solutions with investments level that vary<br />

significantly.<br />

2 - Impact of Renewable Energy Sources on Generation Capacity<br />

Investments: A Stochastic MPEC Approach<br />

Sonja Wogrin, Institute for Research in Technology-ICAI, Comillas<br />

Pontifical University, Alberto Aguilera 25, Madrid, 28015, Spain,<br />

sonja.wogrin@iit.upcomillas.es, Julian Barquin,<br />

Efraim Centeno<br />

Strategic long-term generation capacity planning in liberalized electricity markets<br />

is a very complicated task, mainly because generation companies are confronted<br />

with a vast spectrum of uncertainties, one of the most prominent being demand<br />

fluctuations stemming from renewable energy sources. We propose a stochastic<br />

bilevel model formulated as an MPEC to analyze the impact that renewableinduced<br />

uncertainty has on capacity investment decisions and the optimal<br />

technology mix in the system.<br />

3 - A Three-level Model for Generation and Transmission<br />

Expansion Planning<br />

Javier Contreras, Professor, University of Castilla-La Mancha,<br />

E.T.S. de Ingenieros Industriales, Ciudad Real, 13071, Spain,<br />

Javier.Contreras@uclm.es, Enzo Sauma, David Pozo<br />

We present a three-level model for the expansion of an electric network. The<br />

lower-level model represents the equilibrium of a pool-based market; the<br />

intermediate level represents the Nash equilibrium in generation expansion, and<br />

the upper-level model represents the anticipation of transmission expansion to<br />

the investment in generation and the pool-based market equilibrium. The model<br />

is applied to a realistic power system in Chile to illustrate the methodology and<br />

proper conclusions are reached.<br />

4 - Dynamic Pricing of Peak Generation in Electricity Markets<br />

Heikki Peura, PhD Student, London Business School,<br />

Regent’s Park, London, NW1 4SA, United Kingdom,<br />

hpeura.phd2010@london.edu, Derek Bunn<br />

With reference to electricity, we study the problem of pricing peak production of<br />

an instantly perishable product in a dynamic setting with market power. In a<br />

repeated game with future demand uncertainty, peak producers’ profitability may<br />

hinge on their ability to implicitly collude on prices. Furthermore, diversification<br />

in generation technologies as well as financial constraints in the form of revenue<br />

targets may have significant impacts on peak producers’ pricing decisions.<br />

INFORMS Phoenix – 2012<br />

73<br />

■ SA53<br />

53- North 232 C- CC<br />

Optimization in Energy Procurement and<br />

Cost Allocation<br />

Sponsor: Energy, Natural Res & the Environment/Energy<br />

Sponsored Session<br />

Chair: Ross Baldick, Professor, The University of Texas at Austin,<br />

1 University Station Stop C0803 ENS 502, Austin, TX, 78712,<br />

United States of America, baldick@ece.utexas.edu<br />

1 - Energy Supply Risk Due to Selling Over the Physical<br />

Generation Capacity<br />

Anderson Rodrigo de Queiroz, PhD, MC&E, Rua Silvestre Ferraz<br />

N.81, Itajubá, 37500-000, Brazil, ar_queiroz@yahoo.com.br, Josè<br />

W. Marangon Lima, Luana M. Marangon Lima,<br />

Verònica Etchebehere<br />

In Brazil the electricity market agents have to present full physical generation<br />

coverage, in other words only the generator’s assured energy can be negotiated.<br />

This work explores the possibility of financial leverage in terms of energy by<br />

allowing the negotiation of contracts that extrapolates the physical capacity.<br />

Short-term price simulations are used to value contracts and to study risk. The<br />

procedure gives more flexibility and liquidity to the market amplifying the<br />

business possibilities.<br />

2 - Game-theoretic Allocation of Transmission Costs Taking into<br />

Account Generation and Load Uncertainties<br />

Luiz Carlos Costa Jr, PSR, Praia de Botafogo 228/1701-A,<br />

Rio de Janeiro, RJ, 22250-145, Brazil, luizcarlos@psr-inc.com,<br />

Luiz Mauricio Thomè, Silvio Binato, Mario Veiga Pereira<br />

We extend the Aumann-Shapley allocation scheme to represent uncertainties in<br />

bus loads and energy production of renewables. Two criteria are compared: a<br />

marginal pricing scheme, in which the cost of each circuit is allocated to the<br />

scenario that led to the maximum use of that circuit; and a “tolling” scheme, in<br />

which the cumulative distribution of circuit usage is taken into account. The<br />

methodology will be illustrated for the 5,000 bus Brazilian transmission network.<br />

3 - Stochastic Model of International Fuel Procurement for Coalfired<br />

Plants in Hydrothermal Systems<br />

Fernanda Thomé, Research Engineer, PSR, Praia de Botafogo<br />

228/1701-A, Rio de Janeiro, RJ, 22250145, Brazil,<br />

fernanda@psr-inc.com, André Dias, Silvio Binato, Eduardo Faria<br />

This work presents an optimal strategy for international fuel procurement,<br />

transportation and storage in order to ensure continuous supply of coal-fired<br />

thermal plants. A stochastic programming problem takes into account the<br />

uncertainty associated with inflows in a hydrothermal system and other complex<br />

logistical and commercial aspects related to imported coal handling. The model<br />

results are shown by comparisons between different strategies when applied to<br />

different dispatch scenarios.<br />

■ SA54<br />

SA54<br />

54- Regency Ballroom A- Hyatt<br />

Nicholson Student Paper Prize I<br />

Cluster: Nicholson Student Paper Prize<br />

Invited Session<br />

Chair: Ashish Goel, Stanford University, Stanford, CA,<br />

United States of America, ashishg@stanford.edu<br />

1 - A Polyhedral Study of Multiechelon Lot Sizing with<br />

Intermediate Demands<br />

Minjiao Zhang, Graduate Research Associate, The Ohio State<br />

University, Integrated Systems Engineering, 1971 Neil Ave.,<br />

Columbus, OH, 43210, United States of America,<br />

zhang.769@osu.edu, Simge KüÁükyavuz, Hande Yaman<br />

In this paper, we study a multiechelon uncapacitated lot-sizing problem in series<br />

(m-ULS), where the output of the intermediate echelons has its own external<br />

demand and is also an input to the next echelon. We propose a polynomial-time<br />

dynamic programming algorithm, which gives a tight, compact extended<br />

formulation for the two-echelon case (2-ULS). Next, we present a family of valid<br />

inequalities for m-ULS, show its strength, and give a polynomial-time separation<br />

algorithm. We establish a hierarchy between the alternative formulations for 2-<br />

ULS. In particular, we show that our valid inequalities can be obtained from the<br />

projection of the multicommodity formulation. Our computational results show<br />

that this extended formulation is very effective in solving our uncapacitated<br />

multi-item two-echelon test problems. In addition, for capacitated multiitem,<br />

multiechelon problems, we demonstrate the effectiveness of a branch-and-cut<br />

algorithm using the proposed inequalities.


SA55<br />

2 - Robust Queueing Theory<br />

Chaithanya Bandi, PhD Student, Massachusetts Institute of<br />

Technology, Cambridge, MA, 02139, United States of America,<br />

cbandi@mit.edu, Dimitris Bertsimas, Nataly Youssef<br />

We propose an alternative approach for studying queueing systems by employing<br />

robust optimization as opposed to stochastic analysis. While traditional queueing<br />

theory relies on Kolmogorov’s axioms of probability and models arrivals and<br />

services as renewal processes, we use the limit laws of probability as the axioms of<br />

our methodology and model the queueing systems primitives by uncertainty sets.<br />

In this framework, we obtain closed form expressions for the waiting times in<br />

multi-server queues with heavy-tailed arrival and service processes. These<br />

expressions are not available under traditional queueing theory for heavy-tailed<br />

processes, while they lead to the same qualitative insights for independent and<br />

identically distributed arrival and service times. We also develop an exact calculus<br />

for analyzing a network of queues with multiple servers based on the following<br />

key principle: a) the departure from a queue, b) the superposition, and c) the<br />

thinning of arrival processes have the same uncertainty set representation as the<br />

original arrival processes. We show that our approach, which we call the Robust<br />

Queueing Network Analyzer (RQNA) a) yields results with error percentages in<br />

single digits (for all experiments we performed) relative to simulation, b)<br />

performs significantly better than the Queueing Network Analyzer (QNA)<br />

proposed in Whitt [1983], and c) is to a large extent insensitive to the number of<br />

servers per queue, the network size, degree of feedback, traffic intensity, and<br />

somewhat sensitive to the degree of diversity of external arrival distributions in<br />

the network.<br />

3 - New Functional Characterizations and Optimal Structural<br />

Results for Assemble-to-order M-Systems<br />

Emre Nadar, Carnegie Mellon University, Tepper School of<br />

Business, Pittsburgh, PA, United States of America,<br />

enadar@andrew.cmu.edu, Alan Scheller-Wolf, Mustafa Akan<br />

We consider an assemble-to-order M-system with multiple components, multiple<br />

products, batch ordering of components, random lead times, and lost sales. We<br />

model the system as an infinite-horizon Markov decision process and seek an<br />

optimal control policy: a control policy specifies when a batch of components<br />

should be produced, and whether an arriving demand for each product should be<br />

satisfied.We introduce new functional characterizations for submodularity and<br />

supermodularity restricted to certain subspaces. These enable us to characterize<br />

optimal inventory replenishment and allocation policies under a mild condition<br />

on component batch sizes via a new type of policy: lattice-dependent base-stock<br />

production and lattice-dependent rationing.<br />

■ SA55<br />

55- Regency Ballroom B - Hyatt<br />

Supply Chain and Operations Issues in<br />

Emerging Economies<br />

Cluster: Operations Research in Emerging Economies<br />

Invited Session<br />

Chair: Mili Mehrotra, University of Minnesota, 321 19th Ave. South,<br />

Minneapolis, MN, United States of America, milim@umn.edu<br />

Co-Chair: Tharanga Rajapakshe, Assistant Professor, University of<br />

Florida, Warrington School of Business Administra, Gainesville, FL,<br />

32606, United States of America,<br />

Tharanga.rajapakshe@warrington.ufl.edu<br />

1 - Improving Agricultural Productivity: Impact of Minimum<br />

Support Prices<br />

Tharanga Rajapakshe, Assistant Professor, University of Florida,<br />

Warrington School of Business Administra, Gainesville, FL, 32606,<br />

United States of America,<br />

Tharanga.rajapakshe@warrington.ufl.edu<br />

A Minimum Support Price (MSP) for an agricultural crop is a guaranteed price,<br />

regardless of volume, at which a governmental entity agrees to purchase the crop<br />

from farmers. This work is an effort to understand the influence of MSP on a<br />

homogenous farming community cultivating a single crop. We analyze the impact<br />

of production cost and yield uncertainty on the MSP. Our results explain the role<br />

of MSP in improving productivity and social utility.<br />

2 - Improving the Milk Supply Chain in Developing Countries:<br />

Analysis under Competing Intermediaries<br />

Liying Mu, University of Texas at Dallas, 800 W. Campbell Road,<br />

Richardson, TX, 75080, United States of America,<br />

muliying@utdallas.edu, Milind Dawande, Vijay Mookerjee<br />

Quality issues in milk – arising primarily from deliberate adulteration by<br />

producers — have been reported in many developing countries. High testing cost<br />

and competition between milk stations (which act as intermediaries by buying<br />

milk from producers and selling it to firms) are identified as the main causes for<br />

the low quality of milk. We propose a mechanism to incentivize high-quality milk<br />

with minimum testing, in the presence of competing milk stations.<br />

INFORMS Phoenix – 2012<br />

74<br />

3 - A Stochastic Optimization Based Decision Support System for<br />

Planning in a Process Industry<br />

Goutam Dutta, Professor, Indian Institute of Management,<br />

Production Quantitive Methods Area, Ahmedabad, Gujarat, Gu,<br />

380015, India, goutam@iimahd.ernet.in, Narain Gupta,<br />

Robert Fourer<br />

We introduce a multi-period, multiple scenario optimization based decision<br />

support system. The DSS is based on a two stage stochastic linear program with<br />

recourse for strategic planning in process industry. The model maximizes expected<br />

contribution subject to material balance, facility capacity, and constraints for nonanticipativity.<br />

We describe how the database structure for the stochastic<br />

optimization model is different in comparison to the multi-period deterministic<br />

model.<br />

4 - Agricultural Cooperatives for Alleviating Poverty:<br />

Models and Analyses<br />

Jaehyung An, PhD Student, UCLA Anderson School of<br />

Management, 11140 Rose Ave. #405, 90034, Los Angeles, CA,<br />

90034, United States of America,<br />

jaehyung.an.2013@anderson.ucla.edu, Soo-Haeng Cho,<br />

Christopher Tang<br />

In emerging markets such as Brazil, China and India, the agricultural sector plays<br />

an important role in their economic growth even though many farmers in these<br />

markets are trapped in the poverty cycle. To break this vicious cycle, government<br />

agencies, Non-Governmental Organizations, and social enterprises are helping<br />

farmers to establish agricultural cooperatives (coops). In this paper, we analyze<br />

the impact of these coops on the production quantities, as well as their impact on<br />

the market.<br />

■ SA56<br />

56- Curtis A- Hyatt<br />

Strategy and Strategic Planning<br />

Contributed Session<br />

Chair: Jay Lee, California State University Sacramento, 6000 J St.,<br />

Tahoe Hall 2079, Sacramento, CA, 95819, United States of America,<br />

jlee@csus.edu<br />

1 - Applying Synthetic Control Methodology in Management<br />

Research: Analyzing the Impact of Government Assistance on<br />

Chrysler’s Performance<br />

Brian Richter, Assistant Professor of Business, Economics, and<br />

Public Policy, Richard Ivey School of Business, University of<br />

Western Ontario, 1151 Richmond Street North, London, ON,<br />

N6A3T9, Canada, brian.richter.@mccombs.utexas.edu, Adam<br />

Fremeth, Guy Holburn<br />

We introduce synthetic control to management research by demonstrating how to<br />

apply the technique to quantify the effects of managerial interventions when a<br />

single observation unit receives a treatment on a single date. The problem with<br />

such scenarios is that counterfactual data is typically lacking. The method,<br />

however, allows us to generate counterfactual data systematically from among<br />

untreated firms. In our application, we assess the impact of government assistance<br />

on Chrysler’s performance.<br />

2 - New Methodology for the Mandatory Minimal Outflow<br />

Representation on Hydrothermal Ssystems Planning<br />

Wellington Conceicão, Instituto Federal de Educacão e Tecnologia,<br />

Campus IFET, Juiz de Fora, Brazil, wellingtcc@yahoo.com.br,<br />

André Marcato, Joao Passos Filho, Rafael Brandi, Tales Ramos,<br />

Ivo Silva Junior<br />

This work presents an alternative methodology to supply the mandatory<br />

minimum outflow in the problem of long-term operation planning of<br />

hydrothermal interconnected systems. It was used the strategy of trying to<br />

maintain the storage reservoirs within safe levels through a minimum curve of<br />

stored energy level. The simulation results shows that when using this<br />

formulation a decrease in the minimum outflow deficit is obtained.<br />

3 - Game Theoretic Analysis of Inter-firm R&D Expenditure<br />

Distribution in Semiconductor Manufacturing<br />

Tom Heaps-Nelson, PhD Candidate, Massachusetts Institute of<br />

Technology, 77 Massachusetts Ave., Cambridge, MA, 02139-4301,<br />

United States of America, heaps@mit.edu<br />

Soaring R&D and capital investment costs has left the semiconductor industry<br />

with a handful of large chipmakers and semiconductor equipment suppliers. This<br />

paper employs non-cooperative game theory along with detailed empirical<br />

estimates of firm payoffs as a framework for understanding how the largest<br />

industry players are likely to share the burden of R&D funding for two ongoing<br />

industry-wide process technology transitions: EUV lithography and 450mm<br />

wafers.


4 - Market Partitioning and Competitive Dynamics in<br />

Network-based Industries<br />

Jay Lee, California State University Sacramento, 6000 J St., Tahoe<br />

Hall 2079, Sacramento, CA, 95819, United States of America,<br />

jlee@csus.edu<br />

This paper looks at how market partitioning framework is evolved at networkbased<br />

industry level where mature and emerging players compete with each<br />

other in a dynamic environment, and finally several propositions for further<br />

studies will be briefly discussed at the end.<br />

5 - A Persuasive Power to Accept Change<br />

Mohammad Z. Bsat, Associate Professor, National University,<br />

11736 Vail Court, San Diego, CA, 92131, United States of America,<br />

mbsat@nu.edu<br />

TQM principles made organizations more competitive. Higher education<br />

institutions should embrace TQM practices to undergo transformation & reverse<br />

the lagging effectiveness they suffer from. The efforts to improve education<br />

quality are hindered by the competition that controls higher education<br />

institutions. A collaborative approach to applying TQM principles can lead to a<br />

true transformation of higher education This paper addresses the issue of<br />

overhauling the overall quality of higher education.<br />

■ SA57<br />

57- Curtis B- Hyatt<br />

Bayesian Approach<br />

Contributed Session<br />

Chair: Douglas Jones, Rutgers Business School, 2000 Margerum<br />

Avenue, Lake Como, NJ, 07719, United States of America,<br />

dhjones@rci.rutgers.edu<br />

1 - The Economically Designed Multivariate Bayesian Control Chart<br />

for Short-run Production<br />

Pengwei Zhang, Xiían Jiaotong University, Xi’an, Shaanxi,<br />

P.R.China, Xiían, China, kimi.2004@stu.xjtu.edu.cn, Qin Su<br />

It has been known that Bayesian control charts are optimal tools for statistical<br />

process control but few results have been regarding the influence of the<br />

disturbance occurrence time on process cost. Based on new partition of process<br />

state, process transition matrices under different scenarios were constructed in<br />

this paper employing Markov chain method. Cost function was constructed<br />

iteratively, and finally optimization model for short-run production was<br />

formulated.<br />

2 - A Bayesian Approach for Model Selection in Fractionated Split<br />

Plot Robust Design Experiments<br />

Matthias Tan, Student, Georgia Institute of Technology, 251, 10th<br />

St. NW, Tenth and Home E TAE 208A, Atlanta, GA, 30318,<br />

United States of America, mtan6@gatech.edu, C.F. Jeff Wu<br />

This paper proposes a Bayesian method for model selection in fractionated robust<br />

design experiments that are run as split plot experiments. We employ a Bayesian<br />

hierarchical model that takes into account the split plot error structure. Forward<br />

selection and combined global and local search algorithms are proposed to find<br />

models with high posterior probabilities. The proposed method is used to analyze<br />

three real experiments.<br />

3 - An Optimization Approach to Approximate Bayesian Inference<br />

of Complex Systems<br />

Jose Lainez, Purdue University, 480 Stadium Mall Drive, West<br />

Lafayette, IN, United States of America, jlainez@purdue.edu,<br />

Linas Mockus, Seza Orcun, Gary Blau, Gintaras Reklaitis<br />

Monte Carlo approaches have been widely used for inference. The drawback of<br />

these methods is that they may be computationally expensive. Variational<br />

methods for approximate inference can provide efficient alternatives. However,<br />

the ones developed so far have been targeted for relative simple models. Here, we<br />

propose a variational approach that can handle models expressed as a set of<br />

differential-algebraic equations and whose posterior approximation is represented<br />

by a multivariate distribution.<br />

4 - Predicting Material Accounting Misstatements:<br />

A Bayesian Approach<br />

Feng Xu, Georgia Southwestern State University, 800 GSW State<br />

University Drive, Americus, GA, 31709, United States of America,<br />

fenghsu@hotmail.com, Zinan Zhu<br />

In this paper, we develop Bayesian models for predicting accounting<br />

misstatements. The outputs of the models are probabilistic descriptions for the risk<br />

of conducting misstatement and posterior comparison of the riskiness between<br />

different firms. Empirical analysis results suggest that, compared to classical<br />

models, the Bayesian prediction models improve in terms of reliability and<br />

sensitivity, which provides a useful tool to assess materials accounting<br />

misstatement risks.<br />

INFORMS Phoenix – 2012<br />

75<br />

5 - Bayesian Updating of Norming Tables<br />

Douglas Jones, Rutgers Business School, 2000 Margerum Avenue,<br />

Lake Como, NJ, 07719, United States of America,<br />

dhjones@rci.rutgers.edu, Marco Cors-Lozada<br />

The distribution of the observed test score is estimated by nonparametric Bayesian<br />

methods based on mixture distributions where the mixing weights are obtained<br />

from a Dirichlet Process. We introduce the Dirichlet Processes and related Markov<br />

Change Monte Carlo simulation. The predictive posterior distribution is used to<br />

estimate the norming table. Prior information is used in the base distribution of<br />

the Dirichlet Process.<br />

■ SA58<br />

SA58<br />

58- Phoenix East- Hyatt<br />

Dynamic Control Applications<br />

Sponsor: Applied Probability<br />

Sponsored Session<br />

Chair: Mark Lewis, Professor, Cornell University, School of Ops<br />

Research and Inform. Engin, 226 Rhodes Hall, Ithaca, NY, 14853,<br />

United States of America, mark.lewis@cornell.edu<br />

1 - Dynamic Exploration with Alternative Technologies: When to<br />

Stop Surveying and Invest<br />

Nur Sunar, PhD Candidate, Stanford University, Graduate School<br />

of Business, Stanford, CA, United States of America,<br />

nsunar@stanford.edu, J. Michael Harrison<br />

We consider an oil exploration and production company that can use various<br />

costly technologies to survey a given site, thus reducing uncertainty about the<br />

value of the site. Using a continuous-time Bayesian framework, we characterize<br />

the optimal exploration policy, and the conditions under which it is optimal to<br />

stop surveying and invest in (or abandon) the site.<br />

2 - Optimal Hiring and Job Assignment<br />

Martin Reiman, DMTS, Alcatel-Lucent Bell Labs, 600 Mountain<br />

Ave., Murray Hill, NJ, 07974, United States of America,<br />

marty@research.bell-labs.com, Yue Jin<br />

We consider a model with two types of workers, novices and experts, who process<br />

a Poisson stream of jobs. The available controls involve hiring of novice workers<br />

and assignment of jobs to workers. Novices are promoted after sufficient work<br />

experience, and all workers eventually retire. This problem decomposes naturally<br />

into two time scales, motivating the use of results from nearly completely<br />

decomposable Markov decision processes in our analysis.<br />

3 - Ambulance Allocation using Multi-Class Queueing<br />

Mark Lewis, Professor, Cornell University, School of Ops Research<br />

and Inform. Engin, 226 Rhodes Hall, Ithaca, NY, 14853, United<br />

States of America, mark.lewis@cornell.edu, Kenneth Chong,<br />

Shane Henderson<br />

We consider the problem of allocating various types of emergency calls to<br />

emergency response vehicles. One set of vehicles is typically used for more serious<br />

calls while the other for less serious. However, when all of one kind are busy, the<br />

other may be allocated to an incoming call. The difficulty is in the fact that<br />

mismatching ambulances to calls leaves the system with the vulnerability of<br />

having to allocate an ambulance to a call that it is ill-equipped to handle.<br />

4 - Non-collaborative Systems with Setup Costs<br />

Tugce Isik, Georgia Institute of Technology, 765 Ferst Drive NW,<br />

Atlanta, GA, 30332-0205, United States of America,<br />

tugceisik@gatech.edu, Sigrùn Andradòttir, Hayriye Ayhan<br />

We study a system of two tandem queues with a finite buffer and two flexible<br />

servers. The servers are unable to collaborate and constant setup costs are<br />

incurred when the servers move between stations. We investigate how the server<br />

assignment policy that maximizes the long-run average profit depends on the<br />

magnitude of the setup cost. The optimal policy is characterized for different<br />

buffer sizes.


SA59<br />

■ SA59<br />

59- Phoenix West- Hyatt<br />

Many-server Queues: Approximations and Control<br />

Sponsor: Applied Probability<br />

Sponsored Session<br />

Chair: Itai Gurvich, Northwestern University - Kellogg School of<br />

Management, Evanston, IL, United States of America,<br />

i-gurvich@kellogg.northwestern.edu<br />

1 - Impatience Differentiation in Large-scale Service Systems with<br />

Customer Reentrance<br />

Guodong Pang, Assistant Professor, Pennsylvania State University,<br />

University Park, PA, United States of America, gup3@engr.psu.edu,<br />

Weining Kang<br />

We consider large-scale service systems where customers need to reenter the<br />

system to fulfill their further service requests and the reentry may happen after<br />

some random delay time. We assume that the patience times of new and<br />

reentrant customers may have different distributions. Under mild assumptions on<br />

the general interarrival, service, delay and patience delay times, we investigate the<br />

impact of the impatience differentiation upon the service performance in such<br />

systems.<br />

2 - Staffing and Control for Call Center Outsourcing with Rework<br />

Jiheng Zhang, Hong Kong University of Science and Technology,<br />

Clear Water Bay, Hong Kong, Hong Kong-PRC, j.zhang@ust.hk, Jin<br />

Fang, Eser Kirkizlar<br />

We study a system with both in-house and outsourcer call centers. With certain<br />

probability, customers need to be rerouted to the in-house call center for further<br />

help after receiving service at the outsourcer. The pooling of the two call centers is<br />

allowed. Using a fluid approximation in a heavy traffic regime, we jointly<br />

determine the optimal control rule and the staffing policy that asymptotically<br />

minimize the staffing cost and long run holding cost subject to a service level<br />

constraint.<br />

3 - Non-FCFS Scheduling in Fluid Many-server Queues<br />

Petar Momcilovic, Associate Professor, University of Florida,<br />

303 Weil Hall, P.O. Box 116595, Gainesville, FL, 32611,<br />

United States of America, petar@ise.ufl.edu, Avishai Mandelbaum<br />

We consider non-FCFS scheduling policies in many-server fluid queues. In<br />

particular, we examine time-varying queues under the assumption that the<br />

scheduler knows realizations of customer patience/service times. Implementing a<br />

non-FCFS policy improves the overall system performance in terms of the number<br />

of customers that abandon during overloaded periods.<br />

4 - Scheduling Parallel Servers in the Non-degenerate Slowdown<br />

Diffusion Regime: Asymptotic Optimality<br />

Itai Gurvich, Northwestern University-Kellogg School of<br />

Management, Evanston, IL, United States of America,<br />

i-gurvich@kellogg.northwestern.edu, Rami Atar<br />

We consider the problem of minimizing holding costs in a parallel-server system<br />

operating in a many-server heavy-traffic regime with non-degenerate slowdown<br />

(NDS). The NDS many-server regime is distinct from existing heavy-traffic<br />

regimes. As in the conventional heavy-traffic regime, the asymptotics are captured<br />

by a Brownian control problem, the solution of which exhibits state-space<br />

collapse. We prove an asymptotic lower bound and construct a sequence of<br />

asymptotically optimal policies.<br />

■ SA60<br />

60- Remington- Hyatt<br />

Joint Session RM/Aviation: Robust Airline<br />

Optimization, Alliances and Revenue Sharing<br />

Sponsor: Revenue Management & Pricing & Aviation Applications<br />

Sponsored Session<br />

Chair: Milind Sohoni, Indian School of Business, Gachibowli,<br />

Hyderabad, 500032, India, milind_sohoni@isb.edu<br />

1 - Reducing Flight Delays by Optimizing Block-time Allocation<br />

Mazhar Arikan, University of Kansas, School of Business,<br />

Lawrence, KS, United States of America, mazhar@ku.edu,<br />

Vinayak Deshpande, Milind Sohoni<br />

In this paper, we develop an approach to reallocate block-times across the<br />

network of an airline and analyze the trade-off between total network arrival<br />

delay minutes and network-wide block-time budget based on a stochastic traveltime<br />

model. Using data acquired from a major U.S. airline, we construct an<br />

efficient frontier by optimally allocating block-times while considering target ontime<br />

arrival probability for each flight in the network.<br />

INFORMS Phoenix – 2012<br />

76<br />

2 - Robust Gate Assignment to Reduce Tarmac Waiting Time<br />

Amy Cohn, University of Michigan, Ann Arbor, MI,<br />

United States of America, amycohn@umich.edu, Ryan Chen<br />

We study the problem of assigning flights to gates at an airport, with the goal of<br />

reducing delay associated with an inbound flight waiting on the tarmac because<br />

its gate is still occupied by the preceding outbound flight. This can happen<br />

because the outbound flight is late leaving, the inbound flight is early arriving, or<br />

both. We develop MIP models to assign flights to gates so as to recognize the<br />

inherent stochasticity of the system, and provide empirical analysis based on these<br />

models.<br />

3 - Revenue Sharing in Airline Alliances<br />

Xing Hu, Assistant Professor, University of Oregon, 484 Lillis Hall,<br />

1208 University of Oregon, Eugene, OR, 97401, United States of<br />

America, xingh@uoregon.edu, Rene Caldentey, Gustavo Vulcano<br />

We study codeshare, the practice of independent airlines collaboratively<br />

marketing and operating fights. We propose a two-stage hierarchical approach to<br />

study the revenue sharing rules and decentralized inventory controls from both<br />

cooperative and non-cooperative game approach. Through both analytical and<br />

numerical studies, we find that revenue sharing rule affects the system<br />

significantly. We identify the existence and uniqueness of an admissible and<br />

efficient revenue sharing.<br />

■ SA61<br />

61- Russell- Hyatt<br />

Aviation Support Operations<br />

Sponsor: Aviation Applications<br />

Sponsored Session<br />

Chair: Wenwei Cao, Georgia Institute of Technology, 765 Ferst Dr NW,<br />

Atlanta, GA, United States of America, cww@gatech.edu<br />

1 - Cost Allocation in Fractional Jet Ownership Programs<br />

Wenwei Cao, Georgia Institute of Technology, 765 Ferst Dr NW,<br />

Atlanta, GA, United States of America, cww@gatech.edu, Ozlem<br />

Ergun, Lezhou Zhan, Ellis Johnson<br />

Higher charter and reposition costs have plagued the profitability of the fractional<br />

jet industry since its inception. Incentive programs and pricing adjustments are<br />

introduced to offset these common costs incurred to service the customers. A<br />

central problem in designing these programs is establishing a justifiable cost<br />

allocation scheme. Furthermore, accurate estimates of cost-to-serve are valuable<br />

information to other marketing and operational decisions. In this paper we<br />

develop different mechanisms for the cost allocation problem. The<br />

appropriateness and key trade-offs of the mechanisms are also discussed on the<br />

basis of certain principles of equity and computational performance.<br />

2 - An Integrated Optimal Decision Model for Ground Logistics and<br />

Air Cargo Scheduling<br />

Kwon Gi Mun, PhD Student, Rutgers Business School, #1009B, 1<br />

Washington Park, Newark, NJ, 07102, United States of America,<br />

kwongmun@eden.rutgers.edu<br />

The mathematical model of two-tiered generalized scheduling problem has been<br />

formulated. Thus the optimal assignment solution between airports and facilities<br />

will be computed with the minimum transportation cost at the first stage. And<br />

then the minimum total cost will be calculated with the optimal routing solution<br />

of aircrafts. This research will use a mathematical model with practical constraints<br />

and real data.<br />

■ SA62<br />

62- Borein A - Hyatt<br />

Joint Session Auctions/MSOM: Competitive Sourcing<br />

and Procurement<br />

Cluster: Auctions & Manufacturing & Service Oper Mgmt<br />

Invited Session<br />

Chair: Cuihong Li, University of Connecticut, Storrs, CT, 06269,<br />

United States of America, cli@business.uconn.edu<br />

1 - Incentive Functions for Transportation Procurement Auctions<br />

Diwakar Gupta, University of Minnesota, 111 Church Street S. E.,<br />

Minneapolis, MN, 55455, United States of America,<br />

guptad@me.umn.edu, Justin Azadivar, Yibin Chen<br />

State Transportation Agencies (STAs) use variants of the first-price sealed-bid<br />

auction mechanism to realize low cost, high quality, and fast completion of<br />

highway and bridge construction projects. STAs pay incentives based on the<br />

realized value of an attribute of the work, which may or may not be of value, but<br />

bids do not explicitly include this attribute. We present models to identify costminimizing<br />

incentive functions for agencies, net of any benefits that may accrue<br />

from the attribute.


2 - An Analysis of Scoring and Buyer-determined<br />

Procurement Auctions<br />

Natalia Santamaría Tobar, Universidad de Los Andes,<br />

Departamento de Ingenierìa Industrial, Bogotá, Colombia,<br />

n-santam@uniandes.edu.co<br />

I compare two procurement auction formats (in terms of the expected cost for the<br />

buyer) in which an incumbent competes with a group of entrants. A scoring<br />

auction in which suppliers compete on the adjusted bids or scores, and, a buyerdetermined<br />

auction in which suppliers compete on the price, and the buyer<br />

adjusts the bids with the non-price attributes after the auction to determine the<br />

winner.<br />

3 - Bidding Decisions under Costly Information Acquisition<br />

Brendan See, PhD Candidate, University of Michigan, 1205 Beal<br />

Ave., Ann Arbor, MI, 48104, United States of America,<br />

bdsee@umich.edu, Izak Duenyas, Damian Beil<br />

Procurement research typically assumes that suppliers know their cost to produce<br />

an item. While this may be true for an incumbent supplier, an entrant supplier is<br />

usually less informed. We model this scenario and allow the entrant to learn<br />

additional information at a cost. The entrant can learn prior to the auction or<br />

delay learning and make a less-informed bid. We study the entrant’s strategy and<br />

evaluate how the buyer can influence this strategy through subsidies and other<br />

methods.<br />

4 - Mechanism for Robust Procurements<br />

Yingqian Zhang, Assistant Professor, Erasmus University<br />

Rotterdam, Burg. Oudlaan 50, Rotterdam, 3062 PA, Netherlands,<br />

yqzhang@ese.eur.nl, Sicco Verwer<br />

We model robust procurement as an optimization problem. We show this<br />

problem is NP-complete, and propose a backtracking algorithm to find the optimal<br />

solution. We propose a multi-stage mechanism that is truthful, efficient, and postexecution<br />

individually rational. In the experiments, we compare our mechanism<br />

with an iterated greedy mechanism that represents the current practice in public<br />

procurements, in terms of the expected social welfare and the expected payments<br />

of the auctioneer.<br />

■ SA63<br />

63- Borein B- Hyatt<br />

Behavioral Perspective on Sales and Operations<br />

Contributed Session<br />

Chair: Fei Qin, PhD Candidate, University of Cincinnati, College of<br />

Business, 312 Carl H. Lindner Hall, Cincinnati, OH, 45221,<br />

United States of America, qinfi@mail.uc.edu<br />

1 - An Experimental Investigation of Information Utilization in<br />

Newsvendor Decisions<br />

M.Sinan Gonul, Assistant Professor, METU, Department of<br />

Business Administration, Middle East Technical University,<br />

Ankara, 06800, Turkey, msgonul@metu.edu.tr,<br />

Ayse Kocabiyikoglu, Itir Gogus<br />

In the current study, we aimed to investigate the utilization of information in the<br />

decision making process within classical newsvendor setting. Through an<br />

experimental design, three different types of information (i.e. demand, price and<br />

cost) were systematically withheld/made available and the resultant purchase<br />

decisions were recorded via software specifically tailored for the purpose.<br />

Behavioral patterns are examined, findings are discussed and future research<br />

directions are given.<br />

2 - On the Risk-attitude of Informed Newsvendors<br />

Torsten Gully, University of Cologne, Albertus-Magnus-Platz,<br />

Cologne, 50923, Germany, torsten.gully@uni-koeln.de,<br />

Ulrich Thonemann<br />

The behavior of Newsvendors has been extensively analyzed in the behavioral<br />

operations literature. In essentially all experiments actual order quantites deviate<br />

from the order quantity predicted by the classical Newsvendor model. We show<br />

that risk-attitudes influence the deviation if people can assess the involved risk.<br />

We formulate a model to explain the effect of risk-attitudes on Newsvendor<br />

behavior and report on the validation of our model through a controlled<br />

laboratory environment.<br />

3 - The Strategic Advantage of Behavioral Targeting: How Firm Can<br />

Benefit from Personal Data?<br />

Vincenzo Palermo, Georgia Institute of Technology,<br />

800 West Peachtree St., College of Management, Atlanta, 30308,<br />

United States of America, vincenzo.palermo@mgt.gatech.edu,<br />

Dan Breznitz<br />

We examine whether the access of personal data can create a competitive<br />

advantage for firms investing in behavioral targeting advertising. Specifically, we<br />

analyze a novel proprietary dataset on online investment strategies of 3,889<br />

companies from 2006 to 2011. We identify three strategies: paid search,<br />

behavioral targeting and natural search. We show that an investment strategy<br />

INFORMS Phoenix – 2012<br />

77<br />

based on personal data (behavioral targeting) is more effective than traditional<br />

advertising investment. Moreover, firms can experience positive synergies<br />

between behavioral and traditional investment strategies. Our results suggest that<br />

behavioral targeting lowers information asymmetries about consumers and<br />

therefore it increases advertising effectiveness. Despite its positive impact on firm<br />

performance, the use of personal data raises privacy concerns in that it is<br />

important to protect personal information without undermining the incentives to<br />

invest in online advertising.<br />

4 - Vertically Restrictive Pricing Contracts for Bounded Rational<br />

Customers: Does Equity Matter?<br />

Fei Qin, PhD Candidate, University of Cincinnati, College of<br />

Business, 312 Carl H. Lindner Hall, Cincinnati, OH, 45221, United<br />

States of America, qinfi@mail.uc.edu, Feng Mai, Amit Raturi,<br />

Michael Fry<br />

In a single-period experiment, we test and compare Retailer Fixed Markup (RFM)<br />

policy with Price-only. Through the lenses of RFM contract, we investigate SC<br />

Power (high vs. low markup) and Pricing power (who is the pricing leader, the<br />

manufacturer or the retailer) to see how they would affect subjects’ decision<br />

making process. We then attempt to update our analytical model to incorporate<br />

the findings from the experiment.<br />

■ SA67<br />

SA67<br />

67- Ellis East- Hyatt<br />

Data Fusion for Manufacturing System<br />

Performance Improvement I<br />

Sponsor: Quality, Statistics and Reliability<br />

Sponsored Session<br />

Chair: Jian Liu, Assistant Professor, The University of Arizona, Rm 221<br />

ENGR Building, 1127 E. James E. Rogers Way, Tucson, AZ, 85721,<br />

United States of America, jianliu@sie.arizona.edu<br />

Co-Chair: Ran Jin, Assistant Professor, Virginia Tech., 1145 Perry St.,<br />

Blacksburg, VA, 24060, United States of America, jran5@vt.edu<br />

1 - Calibration and Adjustment of Nanomaterials Property<br />

Prediction Model using Experiment Data<br />

Chun Zhang, Georgia Institute of Technology, 755 Ferst Drive, NW,<br />

Atlanta, United States of America, czhang@fsu.edu, Ben Wang,<br />

Arda Vanli, Richard Liang, Kan Wang<br />

Carbon nanotube sheet, i.e. buckypaper (BP), is a multifunctional nanomaterial<br />

with extraordinary properties. Post treatment using poly (vinyl alcohol) (PVA)<br />

can further enhance the mechanical properties of BP. A finite element based<br />

mechanical model was developed to link PVA-treated BP’s modulus to its<br />

nanostructure characteristics. This model was then calibrated and adjusted using<br />

experimental data. The performance of the calibrated model was tested using the<br />

cross validation process.<br />

2 - Computational Geometry and Data Fusion in CAD/CAM for<br />

Manufacturing System Performance Improvement<br />

Yuan-Shin Lee, Professor, North Carolina State University, 400<br />

Daniels Hall, Ind. Eng., CBox 7906, North Carolina State<br />

University, Raleigh, NC, 27695, United States of America,<br />

yslee@ncsu.edu<br />

This paper presents methods of computational geometry and data fusion in<br />

CAD/CAM for manufacturing system performance improvement. Techniques of<br />

computational geometry processing and data fusion are presented for CAD/CAM<br />

decision optimization. Examples are provided on dealing with optimizing in<br />

CAD/CAM and CNC machining planes determination problems. The presented<br />

methods can be used to automate the traditional, experience-based tool selection<br />

tasks and to reduce the total machining time.<br />

3 - Ensemble Modeling for Manufacturing Scale-up through<br />

Experimental and Observational Data Fusion<br />

Ran Jin, Assistant Professor, Virginia Tech., 1145 Perry St.,<br />

Blacksburg, VA, 24060, United States of America, jran5@vt.edu,<br />

Xinwei Deng<br />

In modern manufacturing scale-up efforts, both experimental and observational<br />

data are available for material, process and quality. Current research efforts<br />

limited their scope on modeling quality-process relationship based on single type<br />

of data. This paper presents an innovative method to model the quality-process<br />

relationship by the fusion of the two types of data. An ensemble modeling<br />

strategy is developed, and case studies in both simulation and wafer<br />

manufacturing are provided.


SA68<br />

4 - Detection of Approximate Periodicity in Categorical Time Series<br />

with Time Intervals<br />

Jian Liu, Assistant Professor, The University of Arizona, Rm 221<br />

ENGR Building, 1127 E. James E. Rogers Way, Tucson, AZ, 85721,<br />

United States of America, jianliu@sie.arizona.edu, Zhenrui Wang,<br />

Mingyang Li, Sean Dessureault<br />

Categorical time series are symbol sequences arranged in the order of occurrence.<br />

When time of occurrences of symbols is also available, order and time<br />

information should be fused to detect periodic patterns. In practice, symbols often<br />

repeat with only approximately equal time intervals. This paper employs<br />

statistical method for the detection of such approximate periodicity. A case study<br />

from mining industry demonstrates the effectiveness of the proposed approach.<br />

5 - Modeling, Experimental Design, and Analysis of<br />

Stereolithography Process for Direct 3-D Printing<br />

Jizhe Zhang, University of Southern California, 3715 McClintock<br />

Avenue, GER 240, Los Angeles, CA, 90089, United States of<br />

America, jizhezha@usc.edu, Qiang Huang, Arman Sabbaghi,<br />

Tirthankar Dasgupta<br />

We propose a systematic model to model and predict the shrinkage process to<br />

address the accuracy problem for Stereolithography (SLA, one technique for 3-D<br />

printing), instead of the traditional finite element simulation or experimental<br />

trial-and-error methods. A variant of Latin Square experimental design is<br />

employed to identify the process model and the experimental outcomes are<br />

analyzed for optimized compensation. One case study is presented to verify the<br />

shrinkage model and compensation.<br />

■ SA68<br />

68- Suite 312- Hyatt<br />

Finance: Portfolio Analysis<br />

Contributed Session<br />

Chair: Ludovic Cales, HEC - University of Lausanne, Bat. Extranef,<br />

Room 253, Lausanne, 1015, Switzerland, ludovic.cales@unil.ch<br />

1 - Absolute Return Portfolios<br />

John Beasley, Brunel University & JB Consultants,<br />

United Kingdom, john.beasley@brunel.ac.uk<br />

We consider the problem of deciding an absolute return portfolio, a portfolio of<br />

assets that is designed to deliver a constant return over time. We present a threestage<br />

mixed-integer zero-one program for the problem that explicitly considers<br />

transaction costs associated with trading. We extend our approach to the problem<br />

of designing portfolios with differing characteristics. Computational results are<br />

given for portfolios derived from universes defined by S&P international equity<br />

indices.<br />

2 - A New Approach to Asset Allocation: Constructing Portfolio<br />

Holdings Directly<br />

Nan Xiong, Carnegie Mellon University, Tepper School of Business,<br />

5000 Forbes Avenue, Pittsburgh, PA, United States of America,<br />

nxiong@andrew.cmu.edu, Javier Peña, Burton Hollifield<br />

In this paper, we propose a new approach to portfolio construction, which<br />

incorporates the estimation and optimization into a one-stage problem. We<br />

propose a new portfolio allocation strategy based on our one-stage formulation.<br />

We show that the resulting portfolio weights are less sensitive to the noisy data.<br />

Moreover, the proposed portfolio tends to perform better out-of-sample. The<br />

numerical results based on empirical and simulated data confirm our findings.<br />

3 - Interactive Portfolio Optimization using Mean-Gini Criteria<br />

Ran Ji, PhD Student, George Washington University, 2201 G St.,<br />

Funger Hall 415H, Washington DC, DC, 20052, United States of<br />

America, jiran@gwu.edu, Miguel Lejeune, Srinivas Prasad<br />

We propose a bi-objective Mean-Gini portfolio optimization model. An interactive<br />

solution procedure is designed to elicit preferences among the efficient portfolios.<br />

Computational results describing the convergence of the interactive procedure<br />

and the out-of-sample performance of the portfolios will be presented.<br />

4 - A Bi-objective Portfolio Model for Supporting Services<br />

in a Hospital<br />

Bartosz Sawik, PhD, Department of Applied Computer Science,<br />

Faculty of Management, AGH University of Science and<br />

Technology, Al. Mickiewicza 30, Krakow, 30059, Poland,<br />

B_Sawik@yahoo.com<br />

This paper presents a bi-objective portfolio model for optimal allocation of<br />

supporting services in a hospital. The services include inventory, financial,<br />

operations management, etc. The optimality criteria of the problem are<br />

minimization of operational costs of supporting services subject to some specific<br />

constraints. The constraints represent specific conditions for resource allocation in<br />

a hospital. The computational experiments based on a real data from a hospital in<br />

Poland.<br />

INFORMS Phoenix – 2012<br />

78<br />

5 - A Rank-based Approach to Cross-sectional Analysis<br />

Ludovic Cales, HEC-University of Lausanne, Bat. Extranef,<br />

Room 253, Lausanne, 1015, Switzerland, ludovic.cales@unil.ch,<br />

Monica Billio, Dominique Guègan<br />

This paper studies the cross-sectional effects present in the market using a new<br />

graph theoretic framework. We model the evolution of a dynamic portfolio, i.e. a<br />

portfolio whose weights change over time, as a function of cross-sectional factors<br />

where the predictive ability of each factor is described by a variable. This<br />

modeling permits us to measure the marginal and joint effects of different crosssection<br />

factors on a given dynamic portfolio. Applications are presented.<br />

■ SA69<br />

69- Suite 314- Hyatt<br />

Finance: Banking and Insurance<br />

Contributed Session<br />

Chair: Komlan Sedzro, Professor, School of Management, University of<br />

Quebec, 315 Ste Catherine Est, succ. Centre-Ville, Montreal, QC,<br />

H3C3P8, Canada, sedzro.k@uqam.ca<br />

1 - Loan Rate Optimization for Financing Platforms<br />

Wei Wang, IBM Research-China, Building 19 Zhongguancun<br />

Software Park, Haidian District, Beijing, 100193, China,<br />

Wangwcrl@cn.ibm.com, Yueting Chai, Hongwei Ding, Jin Dong<br />

Financing platform is an important channel for small and medium enterprises<br />

(SME) to get loan supports. When receiving a loan request from a client, the<br />

financing platform needs to made decision on the loan rate. We build an<br />

optimization model for decision support. The objective is to maximize the profit<br />

and minimize the financing risks. A local-search based heuristics algorithm is<br />

designed to find the optimal solution; the simulation model is built to evaluate<br />

each option.<br />

2 - B-spline Method of Estimating Term Structure of Interest Rate<br />

Yifeng Yan, Xi’an Jiaotong University, No.2269 Mailbox, Xi’an,<br />

710049, China, yanyifeng0123@163.com, Ju’e Guo<br />

This study implements the B-spline method to estimate the term structure of<br />

interest rate using data in Shanghai stock exchange. It shows that the B-spline<br />

method has fine goodness of fitting.The B-spline method can be used as an<br />

effective tool of monitoring interest rate level and formulating monetary policies.<br />

3 - The Informational Advantage of Local Investors: Evidence from<br />

Fund Managers Trades<br />

Kian Ming Tan, Associate Lecturer, University of New South<br />

Wales, Kensington, Sydney, Australia, eric.tan@unsw.edu.au<br />

The economic value of geography for money managers is now well supported in<br />

the literature by evidence of the profitability of local investments. Using data on<br />

both mutual fund equity holdings and fund returns, we find stocks with higher<br />

local investor participation to be associated with stocks abnormal returns during<br />

post event period. In addition, local ownership seems to predict funds increasing<br />

weighting on affected firms which experience lower credit risk.<br />

4 - Finite Precision Errors in Stochastic Financial Networks<br />

Ganesh Perumal, International Institute of Information<br />

Technology, 26/C Electronics City, Bangalore, India,<br />

ganesh_perumal@iiitb.ac.in, Abhilasha Aswal,<br />

G. N. Srinivasa Prasanna<br />

A financial network of money transfers involving multiple currencies may be<br />

erroneous due to the usage of IEEE 754 binary standards. The fluctuations in<br />

currency exchange rates make this a random graph. In this presentation we show<br />

how to exploit such graphs to maximize cumulative errors in favour of some<br />

entity.<br />

5 - Comparing the Performance of Microfinance Institutions in<br />

South America and Asia<br />

Komlan Sedzro, Professor, School of Management, University of<br />

Quebec, 315 Ste Catherine Est, succ. Centre-Ville, Montréal, QC,<br />

H3C3P8, Canada, sedzro.k@uqam.ca, Marie-Héléne Noiseux<br />

We apply multi-directional efficiency analysis to compare the performance of<br />

microfinance institutions (MFIs) in South America and Asia. Indeed, despite their<br />

supposedly importance in combating financial exclusion, many MFIs find it hard<br />

to attain financial independence. This fact in itself justifies the importance of<br />

studies on the performance of MFIs, especially interregional comparisons. The<br />

objective is to see if the MFIs in one region can copy the good practices of another<br />

geographic area.


■ SA70<br />

70- Suite 316- Hyatt<br />

Decision Making over Networks<br />

Cluster: Computational Social Science<br />

Invited Session<br />

Chair: Azarakhsh Malekian, Massachusetts Institute of Technology,<br />

Cambridge, MA, United States of America, malekian@mit.edu<br />

1 - Peers and Pundits: Correlated Opinion Dynamics<br />

Mohamed Mostagir, Massachusetts Institute of Technology,<br />

77 Massachusetts Ave., D32-632, Cambrdige, MA, 02139,<br />

United States of America, mosta@mit.edu, Daron Acemoglu,<br />

Asuman Ozdaglar<br />

We study the simultaneous evolution of the opinion profile and network topology<br />

of a system of N agents. Agents are more inclined to communicate with those<br />

who hold similar opinions, but are also attracted to popular individuals. This<br />

system exhibits strong correlation over time and is difficult to analyze. Regardless,<br />

we show that it converges to a consensus, describe the role of popular agents, give<br />

bounds on the speed of convergence, and characterize that opinion for large<br />

societies.<br />

2 - Striving for Social Status<br />

Greg Stoddard, Northwestern University, 2133 Sheridan Road,<br />

Evanston, IL, 60208, United States of America,<br />

gregS@u.northwestern.edu, Rachel Kranton, Nicole Immorlica<br />

We consider a network of agents producing a positional good; an agent’s utility<br />

for the good is a function of both his intrinsic value for the good and his status, or<br />

production level relative to his neighbors. We show that the set of Nash equilibria<br />

of our game form a complete lattice. We then study the effects of status and<br />

network structure on society. We find that production increases and welfare<br />

decreases with status effects. Network structure can have arbitrary impacts on<br />

both quantities.<br />

3 - Network Security and Contagion<br />

Azarakhsh Malekian, Massachusetts Institute of Technology,<br />

Cambridge, MA, United States of America, malekian@mit.edu,<br />

Daron Acemoglu, Asuman Ozdaglar<br />

We consider the network security problem and compare the properties of the<br />

equilibrium and the socially optimal solutions. An infection percolates over the<br />

network. Agents protect themselves by investing in the security. We delineate<br />

conditions under which there is underinvestment in the equilibrium and also<br />

show which sorts of networks lead to more severe market failures. When attacks<br />

are strategically targeted,we show that there is a new mechanism for<br />

overinvestment.<br />

4 - Competitive Equilibrium in Two Sided Matching Markets with<br />

General Utility Functions<br />

Saeed Alaei, University of Maryland, 4315 Rowalt Dr, APT 201,<br />

College Park, MD, 20740, United States of America,<br />

saeed.a@gmail.com, Azarakhsh Malekian, Kamal Jain<br />

We present the first exact characterization of prices/payoffs at competitive<br />

equilibria in two sided matching markets with non-quasilinear utilities. The<br />

problem has been studied extensively (e.g. Demange, Gale, Quinzii, etc), however<br />

no constructive proof of existence and/or characterization was known for<br />

equilibria. We also derive a mechanism for Ad-Auctions which does not rely on<br />

the assumption that advertisers and search engine have the same belief about<br />

clickthrough rates.<br />

■ SA71<br />

71- Suite 318- Hyatt<br />

Frontiers in Digital Business<br />

Sponsor: eBusiness<br />

Sponsored Session<br />

Chair: Ali Tafti, University of Illinois at Urbana-Champaign,<br />

1206 S. Sixth Street, 350 Wohlers Hall, Champaign, IL, 61820,<br />

United States of America, atafti@illinois.edu<br />

1 - Effort and Quality in Online Crowdsourced Markets: Influence of<br />

Global Economic and Cultural Factors<br />

Jesse Bockstedt, University of Arizona, 1130 E. Helen St., Tucson,<br />

AZ, 85721, United States of America,<br />

bockstedt@email.arizona.edu, Cheryl Druehl, Anant Mishra<br />

One emerging consequence of crowdsourcing is increased competition in global<br />

labor markets for digital work. We analyze how economic and cultural factors<br />

influence the effort and quality of work contributed to these new virtual labor<br />

markets. Using data from a popular online logo design contest site we<br />

demonstrate that GDP per capita, broadband penetration, and Hofstede’s cultural<br />

dimensions are strong predictors of a global digital worker’s effort and work<br />

quality.<br />

INFORMS Phoenix – 2012<br />

79<br />

2 - Firm Capabilities, Entrepreneurial Behavior, and IT Sourcing<br />

Ali Tafti, University of Illinois at Urbana-Champaign, 1206 S. Sixth<br />

Street, 350 Wohlers Hall, Champaign, IL, 61820, United States of<br />

America, atafti@illinois.edu, Ramanath Subramanyam, Rui Guo<br />

We examine the relationship between firm capabilities and IT sourcing strategies,<br />

and the extent that this relationship is framed by specific entrepreneurial<br />

strategies.<br />

3 - Can Social Come to the Rescue? Monetizing Music in the<br />

World of Free<br />

Jui Ramaprasad, Assistant Professor, McGill University,<br />

1001 Sherbrooke West, Montreal, QC, H3H2V1, Canada,<br />

jui.ramaprasad@mcgill.ca, Genevieve Bassellier, Remi Desmeules<br />

We examine the role of social media enabled features and shared social<br />

responsibility (SSR) on willingness to pay (WTP) for online music. Through a<br />

survey-based experiment, we find that a user’s WTP increases if an online music<br />

retailer incorporates the ability to build status and includes concepts of SSR in the<br />

distribution of revenues. This has implications for online music providers, artists,<br />

labels and the music industry as a whole, as well as other digital goods providers.<br />

4 - A Theoretical Assessment of the Development and Success of<br />

Global Entrepreneurial Teams<br />

Joy Oguntebi, Assistant Professor, Rochester Institute of<br />

Technology, 108 Lomb Memorial Dr., Rochester, NY, 14623,<br />

United States of America, joguntebi@saunders.rit.edu<br />

The “globality” phenomenon has led to reduced national dominance and<br />

increased worldwide competition. As such, the growing ambitions of innovationminded<br />

individuals and organizations in this new global market are capitalizing<br />

on the value of global entrepreneurial teams. Such teams are becoming more of a<br />

necessity as their diverse nature enables them to be more responsive to the<br />

external environment. This study investigates the formation and influence of<br />

global entrepreneurial teams.<br />

■ SA72<br />

SA72<br />

72- Suite 322- Hyatt<br />

Cloud Computing Research Trends<br />

Cluster: Cloud Computing<br />

Invited Session<br />

Chair: Ilyas Iyoob, Director, Advanced Analytics, Gravitant - ChainOpt,<br />

4507 A Dorsett Oaks Cir, Austin, TX, United States of America,<br />

ilyas.iyoob@chainopt.com<br />

1 - Cloud Computing Research Survey – 2012 Update<br />

Ilyas Iyoob, Director, Advanced Analytics, Gravitant-ChainOpt,<br />

4507 A Dorsett Oaks Cir, Austin, TX, United States of America,<br />

ilyas.iyoob@chainopt.com<br />

In this presentation, we provide an update of the current research in Cloud<br />

Computing, specifically the business of cloud. Previously we had compared cloud<br />

computing to a pull supply chain in an effort to organize the research domain.<br />

Continuing along the same lines, we show the progress of research over the past<br />

year. At the same time, we identify key shifts in the cloud computing industry<br />

and provide insights on how they may impact future research.<br />

2 - Provisioning for Large Scale Loss Network Systems with<br />

Application in Cloud Computing<br />

Yue Tan, The Ohio State University, 210 Baker Systems Bldg., 1971<br />

Neil Ave., Columbus, OH, 43210, United States of America,<br />

tan.268@osu.edu, Yingdong Lu, Cathy Xia<br />

We present a stochastic modeling approach to guide the resource provisioning<br />

task for future service clouds as the demand grows large. This problem can be<br />

mapped to a capacity planning problem in a general multi-class Erlang loss<br />

network model under quality of service constraint. We give an improved<br />

optimization formulation that is not only easier to solve, but also yields<br />

asymptotically exact provisioning solutions with improved QoS guarantees.<br />

3 - Xpress-Mosel: Modeling Support for Distributed Computing in<br />

Physical and Virtual Networks<br />

Oliver Bastert, FICO, Starly Way, Birmingham, United Kingdom,<br />

OliverBastert@fico.com, Susanne Heipcke<br />

This talk presents the Xpress-Mosel environment and its functionality for<br />

distributed and remote modeling and solving of optimization problems. In<br />

particular, we describe new functionality for remote computing without any need<br />

for a local installation of Xpress that has recently been released. We discuss<br />

several examples of distributed applications implemented by some of our<br />

customers.


SA73<br />

■ SA73<br />

73- Suite 324- Hyatt<br />

Economics<br />

Contributed Session<br />

Chair: Lorena Berumen, Professor, Universidad Panamericana, Augusto<br />

Rodin 498, Col. Insurgentes Mixcoac, Mexico, DF, 03920, Mexico,<br />

laberumen@up.edu.mx<br />

1 - Estimating Real Money Balances for a Selected Asian Country:<br />

A Simultaneous Equation Model<br />

Abul Jamal, Professor, Southeastern Louisiana University, College<br />

of Business, Hammond, LA, 70402, United States of America,<br />

ajamal@selu.edu, Yu Hsing<br />

Equilibrium real balances and interest rates have been the subject of extensive<br />

research. Most studies presume the supply of money to be determined by the<br />

central bank and that the interest rate is only determined by the demand for<br />

money In this paper we use both the demand for and supply of money to<br />

estimate real money balances in a selected Asian country.<br />

2 - The Volatility Characteristics of China’s GEM Market and the<br />

Countermeasures<br />

Jie Xiong, Xi’an Jiaotong University, Postbox 2230, School of<br />

Management, No.28 Xianning West Road, Shaanxi, Xi’an, China,<br />

xiongjie@stu.xjtu.edu.cn, Ju’e Guo, Dong Qian<br />

Select the data of China’s GEM index from June 1, 2010 to October 28, 2011.<br />

EMD method is used to analyze factors that influence the fluctuations of index.<br />

Three factors are found: trend, low-frequency component and high-frequency<br />

component. Than we use the AR-EGARCH-M model to analyze the dynamic<br />

relationship between the returns and volatility of the GEM market and give the<br />

corresponding countermeasures.<br />

3 - The Role of Product Variety and Maturity in the Market<br />

Valuation of IT Intensive Firms<br />

Wael Jabr, Assistant Professor, University of Calgary, 2500<br />

University Dr NW, Calgary, AB, T3A6L5, Canada,<br />

wjabr@ucalgary.ca, Eric (Zhiqiang) Zheng<br />

The pervasiveness and intensive use of Information Technology in every aspect of<br />

firm processes have enabled firms to maintain a portfolio of diverse products and<br />

allowed improved performance. In this study, we address the question of how<br />

companies should best manage their portfolio of IT products under disruptive<br />

environments. We hypothesize that diversity and maturity of products play an<br />

integral part in the firm’s performance and its market value.<br />

4 - A Panel Data Model to Explain Technical Change through IT in<br />

Latin America<br />

Lorena Berumen, Professor, Universidad Panamericana, Augusto<br />

Rodin 498, Col. Insurgentes Mixcoac, Mexico, DF, 03920, Mexico,<br />

laberumen@up.edu.mx, Jen Ai de la Cruz, Gilberto González<br />

Pèrez, Margarita Hurtado, Irma Glinz<br />

In this paper we evaluate the IT’s impact over the conformation of the export<br />

profile of Argentina, Brazil and Mexico through a dynamic panel data model. We<br />

established that the adaptation and learning process is a function of expenditure<br />

on education and innovation, infrastructure and the dynamic of consumption.<br />

<strong>Sunday</strong>, 11:00am - 12:30pm<br />

■ SB01<br />

01- West 101- CC<br />

Genetic Algorithms and Ant Colonies<br />

Contributed Session<br />

Chair: Maria Woodside-Oriakhi, Assistant Professor,<br />

The College of the Bahamas, Oakes Field, Nassau, GT2602, Bahamas,<br />

moriakhi@cob.edu.bs<br />

1 - Genetic Algorithm and New Heuristic in Block Relocation<br />

Problem - Fuel Reduction<br />

Mazen Hussein, PhD Candidate, University of Wisconsin,<br />

Milwaukee, 1559 N. Prospect Ave., Apt # 305, Milwaukee, WI,<br />

53202, United States of America, mhussein@uwm.edu, Matthew<br />

Petering<br />

This research considers a variation of the block relocation problem (BRP). A set of<br />

identically-sized items is to be retrieved from stacks in a specific order using the<br />

minimum fuel consumption. In this work we consider container weight in fuel<br />

consumption calculations and explicitly tracking the containers moves. We<br />

developed a new heuristic that is embedded in a genetic algorithm. Results show<br />

that the methodology is effective in identifying near-optimal parameter settings.<br />

INFORMS Phoenix – 2012<br />

80<br />

2 - Evaluation of Multi-objective Genetic Algorithms on a<br />

Preventive Maintenance Scheduling Model<br />

Kamran Moghaddam, Assistant Professor of Systems Engineering,<br />

Southern Polytechnic State University, 1100 South Marietta<br />

Parkway, Marietta, GA, 30060, United States of America,<br />

kmoghadd@spsu.edu<br />

A multi-objective optimization model to find optimal preventive maintenance and<br />

replacement schedules of a multi-component system is used to evaluate<br />

performance of different multi-objective genetic algorithms. This multi-objective,<br />

nonlinear, mixed-integer model is an NP-hard optimization model that cannot be<br />

solved using exact algorithms. The different performance metrics are used to<br />

evaluating closeness and diversity of non-dominated solutions found by multiobjective<br />

genetic algorithms.<br />

3 - Ant Colony Optimization for the Cardinality Constrained<br />

Portfolio Problem<br />

Maria Woodside-Oriakhi, Assistant Professor,<br />

The College of the Bahamas, Oakes Field, Nassau, GT2602,<br />

Bahamas, moriakhi@cob.edu.bs<br />

This paper extends the mean-variance model of Markowitz to include the<br />

cardinality constraints This limits the number of assets held in the portfolio and<br />

sets bounds on the proportion of an asset held. An ant colony optimization<br />

heuristic algorithm is presented using data from seven real world market indices.<br />

■ SB02<br />

02- West 102 A- CC<br />

Joint Session: DAS/ENRE-Energy: Expert Elicitation<br />

of Energy Technologies: Theory and Practice<br />

Sponsor: Decision Analysis & Energy, Natural Res & the<br />

Environment/Energy<br />

Sponsored Session<br />

Chair: Erin Baker, University of Massachusetts, Amherst, MA,<br />

United States of America, edbaker@ecs.umass.edu<br />

1 - Elicitations of Energy Penalties for Carbon Capture<br />

Technologies<br />

Karen Jenni, Principal, Insight Decisions, LLC, 2200 Quitman St.,<br />

Denver, CO, 80212, United States of America,<br />

kjenni@insightdecisions.com, Gregory Nemet, Erin Baker<br />

We conducted elicitation interviews with 15 experts in carbon capture<br />

technologies, exploring the effects of different energy policies on the viability of<br />

and the energy penalties (EP) for 6 technologies, by 2025. Expert opinions varied<br />

substantially both within a specific technology and between technologies. A<br />

worldwide carbon pricing scenario leads to a decrease in the mean EP of 1% to<br />

10% across the technologies; a scenario of increased US government R&D leads to<br />

a decrease of 6% to 14%.<br />

2 - Online Expert Elicitation Tools: Development and Case Studies<br />

in Energy Technology Assessment<br />

Steve Davis, Senior Research Associate, Carnegie Institution of<br />

Washington, 260 Panama Strett, Stanford, CA, 94305,<br />

United States of America, sjdavis@dge.stanford.edu, Karen Fries<br />

We are developing innovative tools to facilitate online expert elicitation in order<br />

to reduce the time and resources required to characterize uncertainty and the<br />

sources/scope of disagreement among experts. Such characterization is critical to<br />

directing R&D efforts on technical topics. We focus on experts’ subjective<br />

judgments on energy technologies. Here we demonstrate the tools under<br />

development and present results of testing with experts on solar PV and airborne<br />

wind energy systems.<br />

3 - Uncertainty and Surprise in Energy Forecasts:<br />

The Cost of Photovoltaics<br />

Max Henrion, CEO, Lumina Decision Systems, 26010 Highland<br />

Way, Los Gatos, CA, 95033-9758, United States of America,<br />

henrion@lumina.com, Evan Sherwin<br />

Power system planners and other energy analysts would like to know the future<br />

performance and costs of renewable and fossil energy technologies. Several<br />

research groups have used expert elicitation to assess uncertainty using<br />

probability distributions for these quantities. We compare projections for<br />

photovoltaics. Recent dramatic and unexpected cost reductions suggest systematic<br />

overconfidence in expert assessments.


4 - Harmonization and Aggregation of Energy Technology<br />

Elicitations<br />

Erin Baker, University of Massachusetts, Amherst, MA,<br />

United States of America, edbaker@ecs.umass.edu<br />

There have been a number of expert elicitations performed on energy<br />

technologies recently, including 5 studies on solar and 7 on CCS. In this project<br />

we are attempting to harmonize and then aggregate the data from disparate<br />

studies. Harmonizing the data across the elicitations has a number of specific<br />

challenges, as surveys differ along several dimensions, including the metrics<br />

elicited, the timing, and the levels of R&D funding considered.<br />

■ SB03<br />

03- West 102 B- CC<br />

Behavioral Decision Making<br />

Sponsor: Decision Analysis<br />

Sponsored Session<br />

Chair: Manel Baucells, Rand Corporation and University Pompeu<br />

Fabra, 1776 Main Street, Santa Monica, CA, 90401,<br />

United States of America, manel.baucells@upf.edu<br />

1 - Reference Price Comparison, Mental Accounting, and<br />

Anomalies in Consumption-Payment Decisions<br />

Woonam Hwang, PhD Student, London Business School,<br />

Regent’s Park, London, NW1 4SA, United Kingdom,<br />

whwang.phd2009@london.edu, Manel Baucells<br />

We propose a positive theory of consumer choice. When evaluating the hedonic<br />

benefits of consumption and payment decisions, consumers engage in a double<br />

comparison: one between the benefit of consumption and the reference price, and<br />

another between the reference price and the actual price. These comparisons are<br />

governed by proposed laws of mental accounting. Under standard assumptions,<br />

our model predicts various consumer choice anomalies such as sunk cost effects<br />

and the flat-rate bias.<br />

2 - Felicity during Anticipation and Recall<br />

Manel Baucells, Rand Corporation and University Pompeu Fabra,<br />

1776 Main Street, Santa Monica, CA, 90401,<br />

United States of America, manel.baucells@upf.edu, Silvia Bellezza<br />

We propose a set of psychologically plausible assumptions that yield the felicity,<br />

moment-utility, function of a given episode, including the anticipation and recall.<br />

The felicity function is U-shaped during anticipation. Shortening anticipation<br />

makes the event more surprising, and leads to an increase in utility from recall.<br />

The model has prescriptive recommendations to help cope for negative events.<br />

We provide empirical evidence in favor of the main implications of the model.<br />

3 - Model-based Correction of Overprecision Bias in Subjective<br />

Confidence Intervals<br />

Venkat Prava, Johns Hopkins University, 3400 N. Charles Street,<br />

313 Ames Hall, Baltimore, MD, 21218, United States of America,<br />

avadhanulu@gmail.com, Robert Clemen, Benjamin Hobbs,<br />

Melissa A. Kenney<br />

Elicited confidence intervals tend to be overly narrow. We propose a model to<br />

correct this bias based on the normal and bi-normal distributions. Model<br />

parameters are estimated by adjusting expert responses using a sufficient number<br />

of questions with known answers. We apply these models to datasets of expert<br />

elicitations, testing model validity with holdout analysis and quantile-quantile<br />

plots. The bi-normal model fits better, indicating an asymmetric overprecision<br />

bias.<br />

■ SB04<br />

04- West 102 C- CC<br />

Uncovering Risk and Probabilities<br />

Contributed Session<br />

Chair: Saurabh Bansal, Assistant Professor, Pennsylvania State<br />

University, 405 Business Building, University Park, PA,<br />

United States of America, sub32@psu.edu<br />

1 - Stakeholder Perspectives on Risk Scenarios for EMR<br />

Implementing<br />

Chi-Chang Chang, Assistant Professor, Chung-Shan Medical<br />

University Hospital, 110, Sec. 1, Chien-Kuo N. Rd., Taichung,<br />

Taiwan-ROC, changintw@gmail.com, Yu-Hung Cheng<br />

The purpose of this research is to elicit the risk scenarios and stakeholders’ risk<br />

priority during EMR project implementing. We adopt the intuitionistic fuzzy<br />

theory for risk management. We conducted a field study for a medical center of<br />

middle Taiwan to comment the risk of identification, analyses, measurement and<br />

INFORMS Phoenix – 2012<br />

81<br />

control, respectively. Based on the result of this study, we found that the risk<br />

measurement of the IFS be able to elicit the collective risk scenarios ranking of<br />

stakeholders.<br />

2 - A New Method for Valuing Probability Assessment<br />

Brad Powley, PhD Candidate, Stanford University,<br />

475 Via Ortega, Stanford, CA, 94305, United States of America,<br />

bpowley@stanford.edu<br />

A fundamental step in decision analysis is the encoding of probabilities. This<br />

paper introduces a method for valuing probability assessments on a continuous,<br />

uncertain quantity in a way that recognizes an expert’s inconsistency and the cost<br />

of the assessment. I will demonstrate this method using the example of a<br />

pharmaceutical company’s decision whether to market versus license a drug.<br />

3 - Caveats of Decision Rules for Comparing Alternatives under<br />

Incomplete Preference Information<br />

Antti Punkka, Systems Analysis Laboratory, Aalto University<br />

School of Science, Otakaari 1 M, Espoo, 02150, Finland,<br />

antti.punkka@aalto.fi, Ahti Salo<br />

We show that the recommendations provided by several decision rules may<br />

depend on the normalization of the additive value function. This means, for<br />

instance, that these rules may exhibit rank reversals if the two consequences that<br />

are selected for normalizing the value function are replaced by other<br />

consequences. As a remedy, we propose the analysis of all rankings generated by<br />

those value functions that are consistent with the stated incomplete preference<br />

information.<br />

4 - Profile-based Bayesian Method for Assessing Process Risk<br />

Chang-Ho Chin, Associate Professor, Kyung Hee University,<br />

Department of Industrial and Management, Yongin-si, Korea,<br />

Republic of, chin@khu.ac.kr, Aida Mercado Hernandez<br />

A process is a sequence of interdependent and linked activities to accomplish a<br />

predetermined goal. The early detection of process instances terminated without<br />

reaching the goal reduces the loss of resources. We propose a likelihood-based<br />

Byesian method to estimate the abnormal termination probability of process<br />

instances in real time. The estimated probability could be used as a precaution for<br />

the worst or a basis for go/no-go decision.<br />

5 - Probability Elicitation in the Presence of Elicitation Errors<br />

Saurabh Bansal, Assistant Professor, Pennsylvania State University,<br />

405 Business Building, University Park, PA, United States of<br />

America, sub32@psu.edu, Genaro Gutierrez<br />

We develop two analytical approaches to determine the parameters of a<br />

distribution using elicited fractile values in the presence of elicitation errors. Both<br />

approaches minimize the variance in the estimation error for the parameters of<br />

the distribution. We show that both these approaches should be preferred over<br />

approaches that ignore elicitation error and/or elicit only a specific set of fractiles.<br />

■ SB05<br />

SB05<br />

05- West 103 A- CC<br />

IIE Transactions<br />

Sponsor: Quality, Statistics and Reliability<br />

Sponsored Session<br />

Chair: Jianjun (Jan) Shi, The Carolyn J. Stewart Chair and Professor,<br />

Georgia Institute of Technology, 765 Ferst Drive, Room 109, Atlanta,<br />

GA, 30332-0205, United States of America, jianjun.shi@isye.gatech.edu<br />

1 - A Bayesian Framework for Online Parameter Estimation and<br />

Process Adjustment using Categorical Observations<br />

Kaibo Wang, Associate Professor, Tsinghua University,<br />

Department of Industrial Engineering, Beijing, China,<br />

kbwang@tsinghua.edu.cn, Jing Lin<br />

In certain manufacturing processes, low resolution categorical observations could<br />

be obtained as feasible and low-cost surrogates for accurate readings. In this work,<br />

a new online approach for parameter estimation and run-to-run process control<br />

using categorical observations is developed. The new approach is built in the<br />

Bayesian framework; it provides a convenient way to update parameter estimates<br />

when categorical observations arrive gradually in a real production scenario.<br />

2 - Multiscale Monitoring of Autocorrelated Processes using<br />

Wavelets Analysis<br />

Kamran Paynabar, University of Michigan, Ann Arbor, MI,<br />

United States of America, kamip@umich.edu, Judy Jin,<br />

Huairui Guo<br />

This paper proposes a new method to develop multiscale monitoring control<br />

charts for an autocorrelated process that has an underlying unknown ARMA<br />

(2,1) structure. The Haar wavelet transform is used to obtain effective monitoring<br />

statistics by considering the process dynamic characteristics in both time and<br />

frequency domains. Through several simulation scenarios, we show that proposed<br />

control charts outperform other existing charts in terms of detecting changes in<br />

an autocorrelated process.


SB06<br />

■ SB06<br />

06- West 103 B- CC<br />

Analysis of Steady-State Simulation Output<br />

Processes<br />

Sponsor: Simulation<br />

Sponsored Session<br />

Chair: Emily Lada, Operations Research Specialist, SAS, SAS Campus<br />

Dr., Cary, NC, 27513, United States of America, Emily.Lada@sas.com<br />

1 - Evaluation of Batched Quantile Estimation Methods<br />

Dave Goldsman, Georgia Institute of Technology, School of ISYE,<br />

Atlanta, GA, 30332, United States of America, sman@gatech.edu,<br />

Christos Alexopoulos, James Wilson<br />

We study the performance of asymptotically valid confidence intervals (CIs)<br />

methods for steady-state quantiles computed from nonoverlapping batches. Our<br />

results form the basis for the development of fully sequential procedures that<br />

yield CI estimators of steady-state quantiles with user-specified absolute or<br />

relative precision.<br />

2 - Initialization of Finite-horizon Simulations<br />

Peter Glynn, Professor, Stanford University, Huang Engineering<br />

Center, Stanford, CA, 94305, United States of America,<br />

glynn@stanford.edu, Eunji Lim<br />

We introduce a new type of initialization problem that arises in real-time<br />

simulations. In such applications, the state needed to initialize the simulation is<br />

not completely observable, either because monitoring the physical system does<br />

not provide complete information or because the model includes artificial states<br />

that are not observable. We discuss the new initialization issues, make<br />

connections to the filtering literature, and present two algorithms to address these<br />

issues.<br />

3 - The Simulation Start-up Problem: Performance Comparison of<br />

Recent Solution Procedures<br />

James Wilson, Professor, Edward P. Fitts Department of Industrial<br />

Engineering, North Carolina State University, Raleigh, NC, 27695-<br />

7906, United States of America, jwilson@ncsu.edu, Anup Mokashi,<br />

Emily Lada<br />

We summarize the results of a comprehensive experimental performance<br />

comparison of some recent procedures for solving the simulation start-up<br />

problem, including the methods incorporated in MSER-5, N-Skart, waSSP, and<br />

SBatch. Substantial differences in performance are observed, especially in<br />

comparisons of MSER-5 with the latter three procedures.<br />

■ SB07<br />

07- West 104 A- CC<br />

INFORMS DM Student Paper Award Competition<br />

Sponsor: Data Mining<br />

Sponsored Session<br />

Chair: Peter Qian, University of Wisconsin, Madison, WI,<br />

United States of America, peterq@stat.wisc.edu<br />

1 - INFORMS Data Mining Best Student Paper Competition<br />

Peter Qian, University of Wisconsin, Madison, WI,<br />

United States of America, peterq@stat.wisc.edu<br />

Four selected finalists will present their papers in the INFORMS DM Best Student<br />

Paper competition. The winner will be announced at the INFORMS DM business<br />

meeting and all finalists will receive an award certificate.<br />

■ SB08<br />

08- West 104 B- CC<br />

Joint Session Doing Good with Good OR/SPPSN:<br />

Doing Good with Good OR Competition:<br />

Finalist Presentations I<br />

Cluster: Doing Good with Good OR Student Competition & Public<br />

Programs, Service and Needs<br />

Invited Session<br />

Chair: Sila Cetinkaya, Texas A&M University, College Station, TX,<br />

United States of America, sila@tamu.edu<br />

INFORMS Phoenix – 2012<br />

82<br />

1 - The Effect of Budgetary Restrictions on Breast Cancer<br />

Diagnostic Decisions<br />

Mehmet Ayvaci, Assistant Professor, The University of Texas at<br />

Dallas, Jindal School of Management, 800 West Campbell Road,<br />

Richardson, TX, 75080, United States of America,<br />

ayvaci@wisc.edu, Elizabeth Burnside, Oguzhan Alagoz<br />

We develop a finite-horizon constrained Markov Decision Process to model<br />

diagnostic decisions after mammography where we maximize the total expected<br />

quality adjusted life years (QALYs) of a patient under resource constraints.<br />

Comparing to actual clinical practice, using optimal thresholds may result in 22%<br />

cost savings without sacrificing QALYs. Our modeling framework could be used<br />

for evaluating cost-effectiveness of diagnostic procedures.<br />

2 - Dynamic Monitoring of Chronic Disease<br />

Jonathan Helm, Assistant Professor, Indiana University, Kelley<br />

School of Business, ODT, 1309 East Tenth Street, Bloomington, IN,<br />

47405, United States of America, jhelm@umich.edu, Gregg Schell<br />

This research develops new methods for dynamically monitoring chronic disease<br />

to allow better detection of disease worsening with fewer tests. We developed a<br />

prototype and tested it on a major clinical trial with results that significantly<br />

outperform current practice. Our team, including engineers, a clinician, and an<br />

epidemiologist, is working toward integrating our algorithms into widely used<br />

glaucoma testing machines.<br />

3 - Optimal Distribution of Medical Backpacks and Health<br />

Surveillance Assistants in Malawi<br />

Amber Kunkel, Rice University, 6100 Main Street, Houton, TX,<br />

77005, United States of America, agkunkel@gmail.com,<br />

Elizabeth Van Itallie, Duo Wu<br />

The Malawian people face severely limited healthcare access. To address this<br />

issue, we used large-scale p-median and capacitated facility location problems to<br />

create a scalable, three-tiered plan for optimal allocation of Health Surveillance<br />

Assistants (HSAs), HSA designated medical backpacks, and backpack resupply<br />

centers in Malawi. This plan will be used to direct the Beyond Traditional Borders’<br />

HSA backpack program scale-up.<br />

■ SB09<br />

09- West 105 A- CC<br />

Neurophysiology and Decision Making<br />

Sponsor: Multiple Criteria Decision Making<br />

Sponsored Session<br />

Chair: Niklas Ravaja, Professor, Aalto University, School of Economics,<br />

P.O. Box 21255, Helsinki, 00076, Finland, ravaja@mappi.helsinki.fi<br />

1 - Neurophysiological Methods in Decision Making Research<br />

Niklas Ravaja, Professor, Aalto University, School of Economics,<br />

P.O. Box 21255, Helsinki, 00076, Finland,<br />

ravaja@mappi.helsinki.fi, Pekka Korhonen, Outi Somervuori,<br />

Jyrki Wallenius, Murat Koksalan<br />

Neurophysiological or psychophysiological measures, such as<br />

electroencephalography (EEG), facial electromyography (EMG),<br />

electrocardiography (ECG), and electrodermal activity (EDA), have attained<br />

increasing attention in studying emotional and cognitive processes during<br />

decision making. This presentation will discuss the use of these measures. In<br />

addition, some recent decision making studies employing neurophysiological<br />

measures will be presented.<br />

2 - Purchase Behavior and Psychophysiological Responses to<br />

Different Price Levels<br />

Outi Somervuori, Aalto University School of Economics, 00076,<br />

Finland, outi.somervuori@aalto.fi, Niklas Ravaja<br />

The aim of the study was to examine emotional processes in purchase decision.<br />

The participants were presented purchase decision trials with 14 different<br />

products whose price levels were changed while their facial electromyography<br />

(EMG) and electrodermal activity (EDA) were recorded. The results suggest that<br />

low prices and national brand products induce higher positive emotions compared<br />

to high prices and private label products. Also, positive emotions are related to<br />

greater purchase intent.


■ SB10<br />

10- West 105 B- CC<br />

A Robust Optimization Approach to<br />

Stochastic Analysis<br />

Sponsor: Optimization/Stochastic Programming<br />

Sponsored Session<br />

Chair: Nataly Youssef, Graduate Student, Massachusetts Institute of<br />

Technology, 143 Albany St., Apt. 014C, Cambridge, MA, 02139,<br />

United States of America, youssefn@mit.edu<br />

1 - Robust Queueing Theory<br />

Chaithanya Bandi, PhD Student, Massachusetts Institute of<br />

Technology, 02139, United States of America, cbandi@mit.edu,<br />

Nataly Youssef, Dimitris Bertsimas<br />

We study queueing systems by employing robust optimization as opposed to<br />

stochastic analysis. We set the limiting laws of probability as the axioms of our<br />

approach and model queue primitives by uncertainty sets. We analyze single-class<br />

multi-server queueing networks and obtain closed form expressions for the<br />

waiting times with heavy-tailed arrival and service processes. Our approach yields<br />

accurate results compared to simulations and is fairly insensitive to network size<br />

and traffic intensity.<br />

2 - Network Information Theory via Robust Optimization<br />

Dimitris Bertsimas, Massachusetts Institute of Technology, 77<br />

Massachusetts Avenue, Cambridge, MA, United States of America,<br />

dbertsim@mit.edu, Chaithanya Bandi<br />

We provide via robust optimization (RO) inner and outer bounds for the capacity<br />

region of multi-user channels with interference for finite code length n and a<br />

code that matches the inner bound. As n increases,the bounds are tight and lead<br />

to an asymptotic characterization of the capacity region which is a well-known<br />

open problem. The RO problems take the form of rank minimization SDPs for<br />

Gaussian and MILPs for Exponential, Binary and Uniform channels. We report<br />

results for up to 200000 codewords.<br />

3 - Pareto Efficiency in Robust Optimization<br />

Nikos Trichakis, Assistant Professor, Harvard Business School,<br />

Boston, MA, United States of America, ntrichakis@hbs.edu,<br />

Dan Iancu<br />

We argue that the classical robust optimization (RO) paradigm need not produce<br />

solutions that possess the (suitably adapted) property of Pareto optimality. We<br />

illustrate how this could lead to inefficiencies and suboptimal performance in<br />

practice. We introduce and provide a basic theoretical characterization of Pareto<br />

robustly optimal solutions. Numerical studies demonstrate that such solutions<br />

have significant upside compared with ones obtained via classical RO, at no extra<br />

cost or downside.<br />

■ SB11<br />

11- West 105 C- CC<br />

Application of Stochastic Programming I<br />

Contributed Session<br />

Chair: Yang Tan, FedEx Services, 3640 Hacks Cross Rd., Memphis, TN,<br />

38125, United States of America, ytan0920@gmail.com<br />

1 - A Scenario Generation-based Lower Bounding Approach for<br />

Stochastic Scheduling Problems<br />

Lingrui Liao, Google Inc., 1550 Technology Dr., Unit 3085,<br />

San Jose, Ca, 95110, United States of America, lingrui@gmail.com,<br />

Hanif D. Sherali, Subhash C. Sarin<br />

We investigate scenario generation methods to establish lower bounds on the<br />

optimal objective value of stochastic scheduling problems. In contrast to the<br />

Sample Average Approximation approach, we use the idea of recursive stratified<br />

sampling to develop a discrete bounding method. Exact lower bounds for<br />

expectation and conditional value-at-risk objectives are developed, and are<br />

demonstrated using a single machine total weighted tardiness problem with<br />

experimental results.<br />

2 - A Stochastic Programming Approach for Decision-dependent<br />

Uncertainty in Production Planning<br />

Alwin Haensel, Université Paris Sud, Bât 650 Université Paris-Sud<br />

11, Orsay, 91405, France, haensel.alwin@gmail.com,<br />

Marco Laumanns<br />

Regulation pressure on production quality and standards is increasing. A<br />

production plan needs to consider risks of failing the inspections, whose<br />

realizations dependents on the production schedule. This dependency increases<br />

the complexity significantly. The uncertain inspection realizations are modeled by<br />

scenarios generated from given product-site hazards. We propose a general<br />

scenario based stochastic programming approach to compute solutions for riskneutral<br />

and risk-averse decision makers.<br />

INFORMS Phoenix – 2012<br />

83<br />

3 - Stochastic Approach for Resource Allocation and<br />

Facility Utilization<br />

Anirudha Kulkarni, Graduate Research Assistant, Rochester<br />

Institiute of Technology, Rochester, Rochester, NY, 14623,<br />

United States of America, apk2932@rit.edu, Scott Grasman,<br />

Shrikant Jarugumilli<br />

We formulate a stochastic resource allocation model that considers fluctuating<br />

demand over a long planning horizon. The stochastic program includes hiring,<br />

firing, overtime, shift-swapping and cross training. The rationale behind this is to<br />

reduce gaps in assignments and ensure efficient resource utilization. Results<br />

include discussion of the recourse, value of the stochastic solution, and<br />

implementation.<br />

4 - Stochastic Lot-Sizing Model for Deteriorating Items under<br />

Partial Backlogging<br />

Yang Tan, FedEx Services, 3640 Hacks Cross Rd., Memphis, TN,<br />

38125, United States of America, ytan0920@gmail.com<br />

This research is distinguished from most literature by considering the effects of<br />

deterioration and partial backlogging under stochastic customer demand. The<br />

optimal conditions under which a (s, S) policy holds are successfully derived and<br />

the explicit order quantities are obtained by reformulating the problem as a<br />

stochastic programming model.<br />

5 - Linear Profile Monitoring<br />

Azadeh Adibi, Arizona State University, 1265 E. University Dr,<br />

Tempe, AZ, United States of America<br />

In this study,a method is proposed for phase 2 monitoring of linear profiles. Also,<br />

performance of the proposed method is compared with an existing method based<br />

on average run length criterion under different shifts in the model parameters.<br />

■ SB12<br />

SB12<br />

12- West 106 A- CC<br />

Structure of Convex Integer Programs<br />

Sponsor: Optimization/Integer Programming<br />

Sponsored Session<br />

Chair: Marco Molinaro, Carnegie Mellon University, 5000 Forbes Ave,<br />

Pittsburgh, PA, United States of America, molinaro@cmu.edu<br />

1 - Closedness of Mixed Integer Hulls of Second Order Conic<br />

Programming Problems<br />

Diego Moran, Georgia Tech, 755 Ferst Drive NW, Room 422, Main<br />

building, Atlanta, GA, 30332, United States of America,<br />

dmoran@gatech.edu, Santanu Dey<br />

Given rational matrices $A$, $B$ and vector $b$, we show that there exists a<br />

polynomial time algorithm to check the closedness of the convex hull of the set<br />

$\{(x,y)|Ax +By -b \in L, x integral\}$, where $L$ is the Lorentz cone. Moreover,<br />

in the special case of pure integer problems, we present sufficient conditions for<br />

verifying the closedness of the integer hull of the feasible region of a more general<br />

second order conic programming problem (SOCP) that can also be checked in<br />

polynomial time.<br />

2 - Disjunctive Cuts for Convex Mixed Integer Nonlinear Programs<br />

(MINLP)s and Extended Formulations<br />

Mustafa Kilinc, Postdoctoral Researcher, University of Pittsburgh,<br />

3700 O’Hara Street, Pittsburgh, United States of America,<br />

mrk46@pitt.edu, Sina Modaresi, Jeff Linderoth, James Luedtke,<br />

Juan Pablo Vielma<br />

In this work, we study positive effects of extended formulations on generating<br />

cutting planes for convex MINLPs. First, stronger cuts can be generated in an<br />

extended formulation. Second, the performance of a pure LP-based cut<br />

generation method can be improved via extended formulations.<br />

3 - On the Relative Strength of Different Generalizations of Split<br />

Cuts<br />

Marco Molinaro, Carnegie Mellon University, 5000 Forbes Ave.,<br />

Pittsburgh, PA, United States of America, molinaro@cmu.edu,<br />

Sanjeeb Dash, Oktay Gunluk<br />

In this paper we show the complete relationship between the split, cross, crooked<br />

cross and t-branch split closures. We also study the strength of cross cuts from<br />

basic and 2-row relaxations. This answers three open questions left open by Day,<br />

Dash and Gunluk (2010).


SB13<br />

4 - Lower-bound Analyses of the Lift-and-Project Ranks of<br />

Graph-based Polytopes<br />

Yu Hin Au, PhD Candidate, University of Waterloo, 200 University<br />

Ave., W., Waterloo, ON, N2L3G1, Canada, yau@uwaterloo.ca<br />

We’ll discuss some ongoing work on obtaining inapproximability results for<br />

Bienstock-Zuckerberg and Lasserre lift-and-project algorithms on graph-based<br />

optimization problems. This is joint work with Levent Tuncel.<br />

■ SB13<br />

13- West 106 B- CC<br />

Computational Issues on Solving Mixed Integer<br />

Second Order Cone Optimization Problems<br />

Sponsor: Optimization/Linear Programming and Complementarity<br />

Sponsored Session<br />

Chair: Julio Cesar Goez, PhD Candidate, Lehigh University, 18015,<br />

United States of America, jgoez1@gmail.com<br />

1 - Computational Effectiveness of Split Cuts for Second-order<br />

Conic Programming<br />

Sina Modaresi, University of Pittsburgh, 3700 O’Hara Street,<br />

Pittsburgh, United States of America, sim23@pitt.edu,<br />

Mustafa Kilinc, Juan Pablo Vielma<br />

Split cuts are one of the most effective cuts for linear MIPs and they are<br />

equivalent to MIR cuts. We show that this equivalency does not hold for secondorder<br />

conic MIPs by giving examples where split cuts strictly dominate conic MIR<br />

cuts proposed by Atamturk et al.. However, split cuts have to be added as<br />

nonlinear inequalities, while conic MIR cuts can be added as linear inequalities to<br />

the extended formulation. We compare the trade-off between the speed and the<br />

strength of these cuts.<br />

2 - Branch and Bound for Mixed Integer Second Order Cone<br />

Optimization: Impact of Disjunctive Conic Cuts<br />

Julio Cesar Goez, PhD. Candidate, Lehigh University, 18015,<br />

United States of America, jgoez1@gmail.com, Pietro Belotti,<br />

Ted Ralphs, Tamás Terlaky, Imre Polik<br />

We investigate the use of Disjunctive Conic Cuts (DCC) in a Branch and Cut<br />

framework when solving MISOCO problems. Various criteria are explored to<br />

select the disjunctions to build DCCs at different nodes of the tree. Additionally,<br />

we explore different criteria for node selection and branching rules. These<br />

experiments will help us to understand the impact that DCCs have in decreasing<br />

the size of the search tree and the solution time.<br />

3 - Restrict-and-Relax Search for 0-1 Integer Programs<br />

Menal Guzelsoy, SAS, 100 SAS Campus Drive, Cary, NC, 7513,<br />

United States of America, menal.guzelsoy@sas.com,<br />

George Nemhauser, Martin Savelsbergh<br />

We introduce restrict-and-relax search, an algorithm for 0-1 integer programs<br />

that explores a dynamic search tree by not only fixing variables (restricting), but<br />

by also unfixing previously fixed variables (relaxing). Starting by solving a<br />

restricted integer program, we may at any tree node selectively relax/restrict<br />

variables using dual/structural information. A proof-of-concept computational<br />

study demonstrates the effectiveness of the algorithm.<br />

4 - A Regularized Interior-Point Method for<br />

Semidefinite Programming<br />

Ahad Dehghani, McGill University, Montreal, Canada,<br />

ahad.dehghani@mcgill.ca, Jean-Louis Goffin, Dominique Orban<br />

Interior-point methods in semi-definite programming (SDP) require the solution<br />

of a sequence of linear systems which are used to derive the search directions.<br />

Safeguards are typically required in order to handle rank-deficient Jacobians and<br />

free variables. We propose a primal-dual regularization to the original SDP and<br />

show that it is possible to recover an optimal solution of the original SDP via<br />

inaccurate solves of a sequence of regularized SDPs for both the NT and dual<br />

HKM directions.<br />

INFORMS Phoenix – 2012<br />

84<br />

■ SB14<br />

14- West 106 C- CC<br />

Uncertainty in Project Management<br />

Contributed Session<br />

Chair: Bajis Dodin, Professor, University of California, School of<br />

Business Administration, Riverside, CA, 92521, United States of<br />

America, bajis.dodin@ucr.edu<br />

1 - Enumerating Feasible Task Sets with Ordered, Unmeasured<br />

Material Constraints<br />

Jordan Srour, Assistant Professor, Lebanese American University,<br />

P.O. Box 13-5053, Beirut, Lebanon, fjsrour@gmail.com,<br />

Walid Nasrallah<br />

We investigate the solution space for selecting a subset of project tasks under a<br />

resource shortage. The amount of resource required by each task is not known,<br />

but the tasks are fully ordered accordingly. We enumerate the ways to select a<br />

subset of tasks without exceeding the resource constraint. We highlight the<br />

relationship of this enumeration to published number sequences arising from<br />

regular Boolean functions. We provide both an enumeration algorithm and<br />

enumerations up to n=10.<br />

2 - Stochastic Approach for Project Scheduling Based on<br />

Fund Availability<br />

Yuvraj Gajpal, Assistant Professor, King Fahd University of<br />

Petroleum and Minerals, KFUPM Box 634, Dhahran,<br />

Saudi Arabia, gajpaly@gmail.com, Ashraf Elazouni<br />

The paper considers a finance based project where the contractors finance projects<br />

mainly through the owners’ progress payments supplemented by fund procured<br />

through establishing credit-line accounts. In this situation the best proactive<br />

approach for contractor is to schedule construction activities based on the<br />

available finance. A stochastic heuristic approach is proposed to device financebased<br />

schedules of multiple projects.<br />

3 - A Nonlinear Programming Model for Stochastic Project<br />

Crashing<br />

Ronald Davis, Associate Professor, San Jose State University,<br />

College of Business, One Washington Square, San Jose, CA,<br />

95192, United States of America, ronald.davis@sjsu.edu<br />

When beta distributions are used for every activity early start and finish time<br />

distribution in a project network, moment preserving beta approximations for the<br />

sum and product of beta cdfs can be coded in VBA to allow an analytic stochastic<br />

forward pass to be carried out, without simulation. Introduction of crashing<br />

variables and costs yields a nonlinear programming formulation to minimize<br />

crash cost subject to a constraint on mean project duration. Realistic example<br />

SOLVER results are shown.<br />

4 - Portfolio Management in a Highly Uncertain Environment: The<br />

Role of Interdependencies<br />

Olga Kokshagina, PhD Student, Centre for Scientific Management<br />

(CGS), CGS Mines ParisTech, 60 Boulevard Saint-Michel, Paris,<br />

75272, France, olga.kokshagina@mines-paristech.fr, Patrick Cogez,<br />

Pascal Le Masson, Benoit Weil<br />

This work deals with portfolio management strategies in high uncertainty. There<br />

exist strategies that consider projects separately or dependently. Literature shows<br />

first, the dependencies have a tendency to increase complexity and cost of the<br />

system. Second, there is a possibility to share risks in between projects, to<br />

highlight the effect of learning. Our paper investigates the contradictory role of<br />

interdependencies and the relevant management strategies in particular industrial<br />

situations.<br />

5 - Scheduling & Financial Planning in Probabilistic Projects<br />

Bajis Dodin, Professor, University of California, School of Business<br />

Administration, Riverside, CA, 92521, United States of America,<br />

bajis.dodin@ucr.edu, Abdelghani Elimam<br />

In probabilistic projects (PP) required duration and resources for some or all<br />

activities are given as random variables characterized by their own probability<br />

distribution functions (PDFs). Managing a PP requires dealing with several<br />

important issues. In this paper, we analyze the impact of the various stochastic<br />

variations on the duration, and cost of the project. Procedures for determining the<br />

PDFs of project cost and duration, and project schedule are developed.


■ SB15<br />

15- West 202- CC<br />

Software Demonstration<br />

Invited Session<br />

1 - Ziena Optimization LLC - New Developments in the KNITRO<br />

Optimization Solver<br />

Richard Waltz, President, Ziena Optimization LLC, 1801 Maple<br />

Avenue, Ste. 6305, Evanston, IL, 60201 United States of America,<br />

waltz@ziena.com<br />

This software demonstration will highlight the latest developments and<br />

improvements in the KNITRO optimization solver. Benchmark results will be<br />

provided for various problem classes. The demo will also provide an overview of<br />

how to effectively use KNITRO in a variety of environments and interfaces.<br />

2 - Artelys - Optimizing Military Attacks on Multi-Commodity<br />

Supply Chain Networks: a Min-Max Problem Solved with Artelys<br />

Kalis<br />

Sylvain Mouret, Product Manager, Artelys Kalis, 150 N. Michigan<br />

Avenue, Ste. 800, Chicago IL, 60601, United States of America,<br />

ain.mouret@artelys.com<br />

Learn how easy it is to solve general min-max problems arising in adversarial<br />

games with Artelys Kalis. Thanks to its hybrid CP/MIP architecture, it is possible<br />

to build an efficient branch and bound method specialized for such problems in<br />

just a few lines of code. We will demonstrate how Kalis has been embedded in a<br />

full-range operational solution based on the Artelys Network Designer GIS<br />

visualization platform. This solution is currently used to study supply chain<br />

network vulnerabilities with respect to military attacks.<br />

■ SB16<br />

16- West 207- CC<br />

Multi-agent Scheduling Problems<br />

Cluster: Tutorials<br />

Invited Session<br />

Chair: Alessandro Agnetis, Professor, Universita di Siena, Dipartimento<br />

Ingegneria Informazione, via Roma 56, Siena, 53034, Italy,<br />

agnetis@dii.unisi.it<br />

1 - Multi-agent Scheduling Problems – Scheduling Problems<br />

Alessandro Agnetis, Professor, Universita di Siena, Dipartimento<br />

Ingegneria Informazione, via Roma 56, Siena, 53034, Italy,<br />

agnetis@dii.unisi.it<br />

In Multi-Agent Scheduling problems, a number of distinct agents, each owning a<br />

subset of all jobs, share common processing resources. The analysis in this case<br />

focuses on finding efficient and, possibly, fair solutions. After presenting some<br />

motivation, we review basic issues, illustrate the main complexity results, discuss<br />

related problems and point out future research needs.<br />

■ SB17<br />

17- West 208 B- CC<br />

SpORts I<br />

Sponsor: SpORts<br />

Sponsored Session<br />

Chair: Dan Finkel, Technical Staff, Massachusetts Insitute of<br />

Technology, Lincoln Laboratory, 244 Wood Street, Lexington, MA,<br />

02420, United States of America, dfinkel@ll.mit.edu<br />

1 - Serving Strategy in Tennis<br />

Yigal Gerchak, Professor, Tel Aviv University, Ramat Aviv 69978,<br />

Israel, yigal@post.tau.ac.il, Marc Kilgour<br />

Common practice in Tennis is to hit a powerful first serve. Should it fault, the<br />

second serve is usually much weaker. Recently it has been argued that this<br />

strategy is flawed - both serves should be powerful. According to our analysis,<br />

however, the current practice of a weaker second serve appears to be roughly<br />

optimal.<br />

2 - On the (Non-Linear) Probability of Winning a (College)<br />

Football Game<br />

Eric Huggins, Associate Professor of Management, Fort Lewis<br />

College, Durango, CO, 81301, United States of America,<br />

huggins_e@fortlewis.edu<br />

In this paper, we estimate the probability that a football team wins a game based<br />

on the point spread and the over/under. This work is an extension of the Hal<br />

Stern’s 1991 paper with several key differences: 1) We analyze data for both<br />

college and professional football, using a much larger data set. 2) We factor in the<br />

over/under as well as the point spread. 3) We explore several non-linear models<br />

for the probability function.<br />

INFORMS Phoenix – 2012<br />

85<br />

3 - In-play Football Prediction<br />

Nils Rudi, Professor of Technology and Operations Management,<br />

INSEAD, 1 Ayer Rajah Ave., Singapore, 138676, Singapore,<br />

Nils.RUDI@insead.edu, Harry Groenevelt, Bhavani Shanker Uppari<br />

We model the scoring of two football teams as two Poisson processes. For a given<br />

pre-game predictive distribution, we show that there exists a unique pair of<br />

arrival rates, which facilitate in-play prediction as function of time and score. This<br />

result is extended to time and score dependent arrival rates, and comparisons<br />

with Logistic regression is provided. We test the models on an extensive data set<br />

from major European football leagues.<br />

■ SB18<br />

18- West 208 A- CC<br />

Applications of Network Optimization<br />

Contributed Session<br />

SB18<br />

Chair: Alireza Kabirian, Assistant Professor, California State University<br />

Northridge, 18111 Nordhoff St, Northridge, CA, 91330,<br />

United States of America, akabirian@csun.edu<br />

1 - Work Scheduling for Logistics Network<br />

Dening Peng, PhD Candidate, Arizona State University,<br />

1440 E. Broadway Rd., Tempe, AZ, 85282, United States of<br />

America, dening.peng@asu.edu, Pitu Mirchandani<br />

A network optimization model is built for work scheduling on a logistics network,<br />

that exploits features of minimum-cost-flow and scheduling models. Flows on a<br />

certain link can exceed the link capacity but will incur a flow cost that is much<br />

higher than regular flow cost. The objective of the problem is to maintain (or<br />

repair or expand) links within a given time horizon, while minimizing the total<br />

maintenance and flow costs. Experiments are reported on several test networks.<br />

2 - Transmission Network Expansion Planning under Demand<br />

Uncertainty and Risk Aversion<br />

Joao Claro, INESC Porto, Campus da FEUP, Rua Dr. Roberto Frias,<br />

378, Porto, 4200-465, Portugal, jclaro@fe.up.pt, Daniel Delgado<br />

Explicit incorporation of uncertainty in transmission network design can help<br />

improve the balance between important concerns such as network utilization,<br />

demand satisfaction, or dynamic sourcing. We present a mean-risk mixed integer<br />

linear programming model for transmission network expansion planning, and use<br />

it to search for network design insights, with a study of loss-averse design of three<br />

fundamental network building blocks - an independent design, a radial design,<br />

and a meshed design.<br />

3 - Modeling Wildfire Propagation using Stochastic Shortest Path<br />

Mohammad Hajian, PhD, Northeastern University, 39 Orient<br />

Street, Malden, MA, 02148, United States of America,<br />

mohammad.hajian@gmail.com, Emanuel Melachrinoudis<br />

In this paper, a stochastic shortest path algorithm is used to model the fire<br />

propagation on a landscape. The fire landscape is modeled as a network by using<br />

Delaunay triangulation. The time of fire traversal along each edge of the network<br />

is considered to be stochastic, depending on factors such as wind speed and<br />

direction, terrain, and weather conditions. The shortest path algorithm is used to<br />

find the probability distribution of fire arrival at a point of interest.<br />

4 - Role of Information Sharing in Interdependent Dynamic<br />

Infrastructure Networks<br />

Burak Cavdaroglu, Rensselaer Polytechnic Institute, 110 8th<br />

Street, CII Building Suite 5015, Troy, NY, 12180,<br />

United States of America, cavdab@rpi.edu, William Alan Wallace<br />

In case of disruptions in civil infrastructure networks, a timely restoration of these<br />

networks is achieved with an effective selection and scheduling of the network<br />

components to be restored. In today’s society, an infrastructure’s restoration plan<br />

has a greater impact on another’s due to the increasing amount of<br />

interdependencies among them. Using data representing the infrastructures of<br />

New Hanover County, NC, we depicted the impact of sharing the restoration<br />

plans among the infrastructures.<br />

5 - Expansion Planning of Natural Gas Pipeline Networks<br />

Alireza Kabirian, Assistant Professor, California State University<br />

Northridge, 18111 Nordhoff St., Northridge, CA, 91330,<br />

United States of America, akabirian@csun.edu<br />

We develop optimization models for expansion planning of an existing natural gas<br />

pipeline network over a long run horizon. The model is to mainly find where new<br />

pipelines and compressor stations of the network must be installed to minimize<br />

the net present worth of capital investments and operating expenses. We also<br />

develop an evolutionary solution algorithm to solve the model. Numerical results<br />

will be presented at the end showing how the model and the solution algorithm<br />

are applied.


SB19<br />

■ SB19<br />

19- West 211 A- CC<br />

Joint Session Healthcare Logistics/SPPSN: Routing<br />

Problems in Healthcare Operations I<br />

Cluster: Healthcare Logistics & Public Programs, Service and Needs<br />

Invited Session<br />

Chair: Burcu Keskin, University of Alabama, Alston Hall, Box: 870226,<br />

Tuscaloosa, AL, 3587-0226, United States of America,<br />

bkeskin@cba.ua.edu<br />

1 - A Sequential GRASP for the Therapist Routing and<br />

Scheduling Problem<br />

Yufen Shao, Research Engineer, ExxonMobil Upstream Research<br />

Company, 3120 Buffalo Speedway, Houston, TX, 77098, United<br />

States of America, yufen.shao@exxonmobil.com, Ahmad Jarrah,<br />

Jonathan Bard<br />

This talk presents a sequential GRASP for solving a weekly routing and<br />

scheduling problem for therapists. The problem contains both fixed and flexible<br />

patients with respect to appointment times, and two grades of therapists. In Phase<br />

I, feasible solutions are constructed one therapist and one day at a time. In Phase<br />

II, a high-level neighborhood search is proposed to obtain local optima.<br />

Performance is demonstrated using real and randomly generated data sets.<br />

2 - An Optimisation Model for Staff Planning in a<br />

Home Care Organization<br />

Pablo Andres Maya Duque, PhD, University of Antwerp/<br />

Universidad de Antioquia, Ottoveniusstrat 26, box 6, Antwerp,<br />

2000, Belgium, pmayaduque@gmail.com, Peter Goos,<br />

Kenneth Sörensen, Marco Castro<br />

In this talk, we present the core optimization component of a decision support<br />

system that Landelijke Thuiszorg, a non-profit organization that provides home<br />

care services for several provinces in Belgium, will implement in order to assist<br />

the regional service planning. The optimization model takes into account<br />

assignment, scheduling and routing decisions simultaneously, while considering<br />

two objectives, namely the service level and the travelled distance.<br />

3 - Incorporating Patient, Nurse, and Agency Considerations in<br />

Home Health Care Routing<br />

Ashlea Bennett Milburn, Assistant Professor, University of<br />

Arkansas, 4207 Bell Engineering Center, Fayetteville, AR,<br />

United States of America, ashlea@uark.edu, Jessica Spicer<br />

Home health routing and scheduling problems can be modeled as multi-objective<br />

optimization problems, as home health agencies are often interested in creating<br />

nurse routes that achieve a variety of goals. We use a multi-objective tabu search<br />

heuristic to study the relationship among travel cost, nurse consistency (a<br />

measure of patient satisfaction), and balanced workload (an indicator of nurse<br />

satisfaction) objectives. Computational results for a number of realistic scenarios<br />

are presented.<br />

4 - A Multi-period Home Care Scheduling Problem with<br />

Work Balance<br />

Burcu Keskin, University of Alabama, Alston Hall, Box: 870226,<br />

Tuscaloosa, AL, 3587-0226, United States of America,<br />

bkeskin@cba.ua.edu, Shirley (Rong) Li, Charles Schmidt<br />

We consider a home health care scheduling problem for a local hospital with<br />

multiple types of caregivers. We determine the assignment of caregivers to the<br />

patients visited at their homes so that the total routing costs are minimized and<br />

the workload of caregivers are balanced over a planning horizon while satisfying<br />

synchronization, precedence, loyalty, and other practical constraints. We present a<br />

MILP formulation and a branch-and-price solution approach based on Dantzig-<br />

Wolfe decomposition.<br />

■ SB20<br />

20- West 211B- CC<br />

Software Demonstration<br />

Invited Session<br />

1 - American Optimal Decisions - Portfolio Safeguard (PSG):<br />

Advanced Nonlinear Mixed-Integer Optimization Package<br />

Stan Uryasev,American Optimal Decisions, 5214 SW 91 Way, Ste.<br />

#130, Gainesville FL 32608, United States of America,<br />

uryasev@aorda.com<br />

Portfolio Safeguard is an advanced nonlinear mixed-integer optimization package<br />

used in risk management, financial engineering, military, medical and other<br />

applications. Design and solve complex optimization problems with built-in<br />

functions (maximum, StDev, variance, probability, VaR, CVaR, cardinality, fixedcharge,<br />

recourse etc.). See real-life case studies in Windows and MATLAB at<br />

www.aorda.com/aod/psg.action.<br />

INFORMS Phoenix – 2012<br />

86<br />

■ SB21<br />

21- West 212 A- CC<br />

Advances in Networks and Graphs<br />

Contributed Session<br />

Chair: Sivan Altinakar, École Polytechnique de Montréal, C.P. 6079,<br />

Succ. Centre-ville, Montreal, QC, H3C 3A7, Canada,<br />

sivan.altinakar@gerad.ca<br />

1 - Approximating Precedence Network Structure with<br />

Incomplete Information<br />

Adam Graunke, The Boeing Company, P.O. Box 3707, MC 13-98,<br />

Seattle, WA, 98124, United States of America,<br />

adam.a.graunke@boeing.com, Gabriel Burnett<br />

Accurate precedence networks are highly useful for planning and analysis, yet in<br />

large scale production systems, they are difficult, if not impossible, to define. In<br />

this research we investigate precedence networks in the presence of incomplete<br />

precedence information, with the goal of estimating production-critical properties<br />

of the network. Specifically, we investigate critical path analyses and the level of<br />

confidence associated with the results.<br />

2 - Shortest Path with Secure Multipary Computation<br />

Abdelrahaman Aly, Universite Catholique de Louvain, 34,<br />

Voie du Roman Pays, Louvain-la-Neuve, 1348, Belgium,<br />

abdelrahaman.aly@uclouvain.be, Mathieu Van Vyve<br />

In various applications, i.e. elections, auctions, the computation of a global<br />

optimum requires input data from competing parties. A trusted third party to<br />

perform these computations is not guaranteed. Secure Multiparty Computation<br />

(SMC) is an encryption method which does not rely on such third party. The<br />

present research expands SMC’s scenario to Shortest Path problem. We describe<br />

SMC variants of Bellman-Ford and Dijkstra algorithms and compare their<br />

performance with the traditional variants.<br />

3 - Reconstruction of Three Dimensional Objects from Three<br />

Orthogonal Cartesian Bi-plane Projections<br />

Siddhartha Sampath, Arizona State University,<br />

849 W Elna Rae, Tempe, AZ, United States of America,<br />

Siddhartha.Sampath@asu.edu, Pavithra Ramamoorthy,<br />

Pitu Mirchandani<br />

This application describes a network flow model for reconstructing the threedimensional<br />

shape of a three dimensional object from biplane x-ray readings for<br />

all three orthogonal Cartesian planes.Each two-dimensional cross-section consists<br />

of one region or view of the object whose image is to be reconstructed.We can use<br />

apriori information to constrain the number of solutions, and then to obtain most<br />

likely reconstruction.<br />

4 - Breaking Symmetry in Consecutive Edge-coloring<br />

Sivan Altinakar, École Polytechnique de Montreal, C.P. 6079,<br />

Succ. Centre-ville, Montreal, QC, H3C 3A7, Canada,<br />

sivan.altinakar@gerad.ca, Alain Hertz, Gilles Caporossi<br />

Consecutive edge-coloring, a special case of edge-coloring in graph theory, aims to<br />

minimize the sum of the span of colors (integers) incident to each node. This has<br />

applications in scheduling. It is also NP-hard, and may be difficult to solve exactly<br />

even for a very small number of vertices. We compare different modeling<br />

approaches in Mixed Integer Programming and Constraint Programming, with an<br />

emphasis on the latter, and subsets of Lex-Leader constraints for efficient<br />

symmetry breaking.<br />

■ SB22<br />

22- West 212 B- CC<br />

COIN-OR Multi-Threading Software<br />

Sponsor: Computing Society<br />

Sponsored Session<br />

Chair: Bradley Bell, Senior Research Scientist/Enginer, University of<br />

Washington, IHME, 2301 Fifth Ave., Suite 600, Seattle, WA, 98121,<br />

United States of America, bradbell@seanet.com<br />

1 - Could We Use a Million Cores to Solve a Single Integer<br />

Program?<br />

Ted Ralphs, Associate Professor, Lehigh University, 200 West<br />

Packer Avenue, Bethlehem, PA, 18015, United States of America,<br />

ted@lehigh.edu, Thorsten Koch, Yuji Shinano<br />

Given the steady increase in cores per CPU, it is only a matter of time before<br />

supercomputers will have a million or more cores. In this talk, we investigate the<br />

opportunities and challenges that will arise when trying to utilize the distributed<br />

multi-core architectures that have recently become pervasive to solve a single<br />

integer linear optimization problem. We raise the question whether best practices<br />

in sequential solution of ILPs will be effective in massively parallel environments.


2 - A Multi-core Benchmark used to Improve<br />

Algorithmic Differentiation<br />

Bradley Bell, Senior Research Scientist/Enginer, University of<br />

Washington, IHME, 2301 Fifth Ave., Suite 600, Seattle, WA,<br />

98121, United States of America, bradbell@seanet.com<br />

We present an application of Newton’s method that finds all the zeros of a nonlinear<br />

function in an interval. This is being used as a benchmark to improve the<br />

multi-core performance of the COIN-OR open source AD software package<br />

CppAD. Different threading systems, and different versions of this software<br />

package, are easily compared for speed of execution. As an example of the use of<br />

this benchmark, we compare the results for three versions of the software<br />

package.<br />

3 - Parallelization of a Primal-dual IPM for SDP using OpenMP<br />

Brian Borchers, New Mexico Tech, Mathematics Department,<br />

801 Leroy Place, Socorro, NM, 87801, United States of America,<br />

borchers@nmt.edu<br />

CSDP is software package for semidefinite programming that uses a primal-dual<br />

interior point method. We discuss how the software was parallelized using<br />

OpenMP, and discuss the parallel performance of the algorithm on problems of<br />

varying size.<br />

4 - Application of SIMD Instructions in Solving Random<br />

3-dimensional Assignment Problems<br />

Mohammad Mirghorbani, The University of Iowa, 3131 Seamans<br />

Center, Iowa City, IA, 52242, United States of America,<br />

seyedmohamma-mirghorbaninokandeh@uiowa.edu,<br />

Pavlo Krokhmal<br />

We show how SIMD instructions can be utilized to vectorize an existing branch<br />

and bound method, BitCLQ, designed to enumerate k-cliques in special k-partite<br />

graphs. The k-cliques found map to guaranteed high-quality solutions of random<br />

3-dimensional assignment problems. We observed up to 100% improvement in<br />

the performance of BitCLQ on the same machine after vectorization.<br />

■ SB23<br />

23- West 212 C- CC<br />

Edelman 2012 Finalists II<br />

Sponsor: CPMS, The Practice Section<br />

Sponsored Session<br />

Chair: Stephen Graves, Massachusetts Institute of Technology, Sloan<br />

School of Management, 77 Massachusetts Avenue, Cambridge, MA,<br />

02139, United States of America, sgraves@MIT.EDU<br />

1 - Carlson Rezidor Hotel Group Maximizes Revenue with<br />

Improved Demand Management and Price Optimization<br />

Pelin Pekgun, Assistant Professor, University of South Carolina,<br />

Moore School of Business, 1705 College Street, Columbia, SC,<br />

29208, United States of America, Pelin.Pekgun@moore.sc.edu,<br />

Suresh Acharya, Kathleen Mallery, Kyle Christianson, Ronald<br />

Menich, Phillip Finch, Frederic Deschamps, James Van Sistine,<br />

James Fuller<br />

Carlson Rezidor Hotel Group collaborated with JDA Software Group on a highly<br />

innovative revenue optimization project that started with enterprise demand<br />

forecasting in 2007. It was followed by a large-scale network optimization<br />

solution to dynamically optimize stay night rates based on price elasticity,<br />

competitor rates, remaining inventory, demand forecast and business rules.<br />

Compliant hotels consistently showed a 2-4% revenue improvement,and<br />

increased revenue by more than $16 million annually.<br />

2 - Optimizing Capital Investment Decisions at Intel Corporation<br />

Feryal Erhun, Stanford University, Stanford, CA, United States of<br />

America, ferhun@stanford.edu, Karl Kempf, Erik Hertzler,<br />

Timothy Rosenberg, Chen Peng<br />

Intel spends over $5B annually on manufacturing equipment. With increasing<br />

lead times from equipment suppliers and increasing difficulty in forecasting<br />

market demand, optimizing capital investment decisions is a significant<br />

managerial challenge. We describe the Velocity Program and the DMEP<br />

framework, which have benefited Intel hundreds of millions of dollars in<br />

documented cost savings and at least $2B in revenue upside for a manufacturing<br />

process transition during a period of economic crisis.<br />

INFORMS Phoenix – 2012<br />

87<br />

■ SB24<br />

SB24<br />

24- West 213 A- CC<br />

Joint Session HAS/SPPSN: Pandemic Modeling<br />

and Planning<br />

Sponsor: Health Applications Society & Public Programs,<br />

Service and Needs<br />

Sponsored Session<br />

Chair: Dionne Aleman, University of Toronto, 5 King’s College Road,<br />

Toronto, On, M5S 3G8, Canada, aleman@mie.utoronto.ca<br />

1 - Quantifying the Value of Information for Inferring Contagion<br />

Patterns in Social Activity Graphs<br />

Lauren Gardner, Lecturer, University of New South Wales, UNSW,<br />

Sydney, 2052, Australia, laurengardner84@gmail.com, David<br />

Fajardo<br />

The model presented here seeks to predict the infection pattern which depicts the<br />

current state of the network for an ongoing outbreak of a communicable disease.<br />

This is accomplished by inferring the most likely path of infection through a<br />

contact network under the assumption of partially available infection data. The<br />

problem is formulated as a bi-linear integer program, and heuristic solution<br />

methods are developed based on iteration of two sub-problems which can be<br />

solved much more efficiently.<br />

2 - Developing Non-pharmaceutical Intervention Strategies for<br />

Pandemic Influenza Mitigation<br />

Tapas Das, Professor, Department of Industrial and Management<br />

Systems Engineering, University of South Florida, Industrial<br />

Engineering, Tampa, FL, United States of America, das@usf.edu,<br />

Dayna Martinez<br />

In this paper we examine the interactions between the parameters of virus<br />

epidemiology, social behavior, and non-pharmaceutical interventions (NPIs). This<br />

examination is conducted using an agent-based simulation model and designed<br />

statistical experiments. Results are used to design effective NPI strategies for<br />

pandemic influenza mitigation. Some numerical results are presented for various<br />

virus transmissibility scenarios.<br />

3 - Evaluation of Strategies to Mitigate Contagion Spread using<br />

Social Network Characteristics<br />

Mario Ventresca, University of Toronto, 5 King’s College Road,<br />

Toronto, On, M5S 3G8, Canada, mventresca@gmail.com,<br />

Dionne Aleman<br />

We study the effects of graph-based mitigation strategies with respect to their<br />

ability to contain disease spread. Evaluation is performed on a social network<br />

constructed from census data of the Greater Toronto Area of 5 million individuals.<br />

One outcome of the analysis highlights the pitfalls of betweenness and centrality<br />

measures for maximum mitigation given an unknown initial spreader. Our<br />

analysis focuses on pandemic disease, but the approach is applicable to any<br />

network contagion.<br />

4 - Prediction of Demand Surges for Immunization During<br />

Influenza Pandemics<br />

Michael Beeler, University of Toronto, 5 King’s College Road,<br />

Toronto, ON, M5S 3G8, Canada, mfbeeler@gmail.com,<br />

Michael Carter, Dionne Aleman<br />

A time-series model is constructed to predict surges in turnout at mass<br />

immunization clinics during influenza pandemics. Variables include media<br />

coverage, weather conditions, day of the week, and estimated weekly infection<br />

rate. The model is based on Toronto clinic turnout data during the H1N1<br />

pandemic in 2009.


SB25<br />

■ SB25<br />

25- West 213 B- CC<br />

Radiation Therapy Treatment Planning I<br />

Sponsor: Health Applications Society<br />

Sponsored Session<br />

Chair: Edwin Romeijn, Professor, University of Michigan, IOE<br />

Department, 1205 Beal Avenue, Ann Arbor, MI, 48109-2117,<br />

United States of America, romeijn@umich.edu<br />

1 - A Column-generation-based Technique for Multi-criteria Direct<br />

Aperture Optimization<br />

Ehsan Salari, Research Associate, Massachusetts General Hospital<br />

and Harvard Medical School, Francis H Burr Proton Therapy,<br />

55 Fruit Street, Boston, MA, 02114, United States of America,<br />

salari.ehsan@mgh.harvard.edu, David Craft, Jan Unkelbach<br />

Multi-criteria optimization (MCO) has proved to be a promising approach to<br />

radiation therapy treatment planning. MCO is typically employed in the Fluencemap<br />

optimization stage to find a Pareto-optimal solution that yields the desired<br />

trade-off between treatment evaluation criteria. In this study we investigate the<br />

extension of the MCO approach to the direct aperture optimization problem and<br />

develop heuristics to obtain a collection of apertures that can approximate the<br />

Pareto surface.<br />

2 - Determining Convex Objective Functions and Importance<br />

Factors in Multi-criteria IMRT Planning<br />

Taewoo Lee, University of Toronto, 5 King’s College Road, Toronto,<br />

Canada, taewoo.lee@utoronto.ca, Michael Sharpe, Timothy Chan,<br />

Tim Craig<br />

In multi-criteria optimization, objective function parameters are often determined<br />

by a trial-and-error process. Multi-criteria IMRT planning typically involves many<br />

objective functions, which leads to a large parameter space to search over. We<br />

develop an inverse optimization method to determine convex objective functions<br />

and parameters that are most critical in treatment planning. Results show the<br />

potential to both streamline the planning process and increase the treatment<br />

effectiveness.<br />

3 - The Effect of Tumor Repopulation on Fractionation Schedules in<br />

Radiation Therapy<br />

Jagdish Ramakrishnan, Massachusetts Institute of Technology, 77<br />

Massachusetts Avenue, Cambridge, MA, United States of America,<br />

jagdish@mit.edu, David Craft, Thomas Bortfeld, Jan Unkelbach,<br />

John N. Tsitsiklis<br />

We consider optimizing the fractionation schedule and the number of treatment<br />

days for radiation therapy. The tumor control probability is maximized subject to<br />

a constraint on the normal tissue complication probability. We consider both<br />

exponential and gompertzian tumor repopulation between treatment fractions in<br />

the linear-quadratic formalism. Such a framework provides insights as to which<br />

types of treatment protocols (e.g., hypo-fractionation) are beneficial for various<br />

disease sites.<br />

4 - A Method for Improving the Dose Distribution Quality of<br />

Multi-criteria Radiation Therapy Plans<br />

Rasmus Bokrantz, KTH Royal Institute of Technology, SE-100 44,<br />

Stockholm, Sweden, bokrantz@kth.se<br />

This talk considers an approach to radiation therapy planning where possible<br />

treatment options are explored through realtime interpolation over precomputed<br />

solutions. A method is presented that improves the quality of interpolated<br />

solutions by minimizing a projective distance to the nondominated frontier under<br />

constraints on maintained dose distribution quality. Also, minimization of dose<br />

changes during conversion into deliverable machine settings are discussed in view<br />

of the presented method.<br />

■ SB26<br />

26- North 221 A- CC<br />

Emerging Topics in Supply Chain Management<br />

Sponsor: Manufacturing & Service Oper Mgmt<br />

Sponsored Session<br />

Chair: Li Chen, Assistant Professor, Duke University, 100 Fuqua Drive,<br />

Durham, NC, 27708, United States of America, li.chen@duke.edu<br />

1 - Integrating Inventory Replenishment and Cash Payment<br />

Decisions in Supply Chains<br />

Wei Luo, Duke University, 100 Fuqua Drive, Durham, NC,<br />

United States of America, wei.luo@duke.edu, Kevin Shang<br />

We provide a modeling framework that integrates financial flows into a two-stage<br />

supply chain where each location procures inventory based on cash available. We<br />

consider different payment schemes and derive joint optimal and near-optimal<br />

INFORMS Phoenix – 2012<br />

88<br />

inventory and cash policies. Our study demonstrates that an effective cash<br />

payment policy can mitigate the supply disruption risk and improve the overall<br />

supply chain efficiency.<br />

2 - On the Profitability of an Eco-Friendly Supply Chain<br />

Yang Li, PhD Student, Duke University, 100 Fuqua Drive,<br />

Durham, NC, 27708, United States of America,<br />

yang.li2@duke.edu, Fernando Bernstein, Kevin Shang<br />

We study a two-stage supply chain for eco-friendly problems. The production<br />

technology for eco-friendly products is more costly, but these products use<br />

components with less fossil-fuel content than regular products. In particular, ecofriendly<br />

products are less exposed to the price volatility of petroleum. We<br />

examine scenarios in which eco-friendly products are more profitable.<br />

3 - Competitive Quality Choice and Remanufacturing<br />

Adem Orsdemir, Kenan Flagler Business School, University of<br />

North Carolina, Chapel Hill, NC, 27599, United States of America,<br />

adem_orsdemir@kenan-flagler.unc.edu, Eda Kemahlioglu Ziya,<br />

Ali Parlakturk<br />

We consider an Original Equipment Manufacturer who faces competition from an<br />

Independent Remanufacturer. We explicitly characterize how OEM competes<br />

with IR in equilibrium. IR’s entry threat as well as its entry can decrease<br />

consumer and social surplus. We show either weak IR or strong IR is desirable for<br />

reducing the environmental impact. Comparing our results with benchmarks in<br />

which OEM remanufactures suggests that encouraging IRs to remanufacture in<br />

lieu of OEMs may not benefit environment.<br />

4 - Fixing Phantom Stockouts: A POS-Based Shelf Inspection<br />

Model<br />

Li Chen, Assistant Professor, Duke University, 100 Fuqua Drive,<br />

Durham, NC, 27708, United States of America, li.chen@duke.edu<br />

”Phantom stockout” is a retail stockout phenomenon caused by shelf execution<br />

failure and/or product shrinkage (e.g., theft and spoilage). In this paper, we<br />

propose a simple but effective partially-observable Markov decision process<br />

(POMDP) model to tackle this problem. We show that the optimal shelf<br />

inspection policy is a threshold policy based on the number of consecutive zerosales<br />

periods. We further extend the analysis to models with time-varying<br />

parameters.<br />

■ SB27<br />

27- North 221 B- CC<br />

Supply Chain Models with Multi-sourcing and<br />

Information Updates<br />

Sponsor: Manufacturing & Service Oper Mgmt<br />

Sponsored Session<br />

Chair: Eylem Tekin, Instructional Associate Professor, University of<br />

Houston, Department of Industrial Engineering, Houston,<br />

United States of America, etekin@central.uh.edu<br />

1 - Inventory Replenishment and Demand Allocation Decisions for<br />

Multi-Sourced Items<br />

Abhilasha Katariya Prakash, PhD Student, Texas A&M University,<br />

503 nagle st, apt 102, college station, TX, 77840, United States of<br />

America, abhilashapk@neo.tamu.edu, Eylem Tekin, Sila Cetinkaya<br />

We consider a manufacturer using multi-sourced parts from a contractual vendor<br />

(CV) and a spot market (SM). The CV holds inventory at a vendor managed hub<br />

and charges a fixed unit price under a quantity commitment contract. Inventory<br />

procured from the SM with volatile prices is held at an advance purchase hub.<br />

The overall problem deals with when and how much to order from each source<br />

and how to allocate demand to the alternative hubs.<br />

2 - Dynamic Inventory Replenishment Decisions with Bayesian<br />

Learning of Supply Yield Uncertainty<br />

Baykal Hafizoglu, Arizona State University, 699 S Mill Avenue,<br />

Tempe, AZ, 85281, United States of America, baykal@asu.edu,<br />

Sibel Salman, Esma Gel<br />

We consider a periodic-review inventory replenishment problem with yield<br />

uncertainty, where the quantity that the supplier ships in response to an order is<br />

random. We assume that the parameters that govern the supplier’s yield are not<br />

known with certainty in advance. We propose a Bayesian updating scheme that<br />

learns supplier’s yield parameters over time. We compare performance of<br />

Bayesian learning scheme with other strategies such as safety stock policy, and<br />

simple heuristics.


3 - Strategic Inventories and Dynamic Coordination with<br />

Production Cost Learning<br />

Xiuli He, Assistant Professor, University of North Carolina-<br />

Charlotte, 9201 University City Blvd, Charlotte, NC, 28223,<br />

United States of America, xhe8@uncc.edu, Tao Li, Suresh Sethi<br />

We consider a two-period decentralized supply chain in which the manufacturer’s<br />

production cost declines with cumulative production due to stochastic cost<br />

learning. We investigate the impact of learning curve effect on the value of<br />

strategic inventory to the channel members. We construct dynamic revenue<br />

sharing contracts that coordinate the channel.<br />

4 - Supply-side Rationale for Bundling<br />

Qingning Cao, University of Texas-Dallas, School of Management,<br />

800 West Campbell Road, Dallas, TX, 75080, United States of<br />

America, qingning.cao@utdallas.edu, Jun Zhang, Xianjun Geng,<br />

Kathryn Stecke<br />

We examine a firm’s capacity decisions and restrictions on a popular product<br />

when the market is uncertain and the firm has an option to bundle two products.<br />

Deriving the firm’s optimal bundling strategy, this talk sheds light on the interplay<br />

between a firm’s capacity (supply-side) and bundling (demand-side) decisions.<br />

■ SB28<br />

28- North 221 C- CC<br />

Customer Behavior and Operations Models<br />

Sponsor: Manufacturing & Service Oper Mgmt<br />

Sponsored Session<br />

Chair: Fuqiang Zhang, Olin Business School, Washington University, St.<br />

Louis, United States of America, Fzhang22@wustl.edu<br />

1 - Bounded Rationality in Service Systems<br />

Gad Allon, Northwestern University, 2001 Sheridan Rd, Evanston,<br />

IL, United States of America, g-allon@kellogg.northwestern.edu,<br />

Achal Bassamboo<br />

The traditional economics and queueing literature typically assume that<br />

customers are fully rational. In contrast, in this paper, we study canonical service<br />

models with boundedly rational customers. We capture bounded rationality using<br />

a framework in which better decisions are made more often, while the best<br />

decision needs not always be made.<br />

2 - Consumer-driven Competition Sets<br />

Serguei Netessine, Professor, INSEAD, Boulevard de Constance,<br />

Fountainbleau, 77305, France, Serguei.Netessine@insead.edu,<br />

Jun Li<br />

We use clickstream data from Expedia to construct and analyze hotel competition<br />

sets. We find that these competition sets are drastically different from the<br />

traditionally used attribute-based competition sets.<br />

3 - Competing for Socially Conscious Consumers: The Role of<br />

Supply Chain Structure<br />

Robert Swinney, Associate Professor, Graduate School of Business,<br />

Stanford University, 655 Knight Way, Stanford, CA, 94305, United<br />

States of America, swinney@stanford.edu, Ruixue Guo, Hau L. Lee<br />

We analyze a duopoly in which two competing firms choose whether to adopt<br />

socially responsible manufacturing practices. Doing so attracts demand from<br />

competing firms-those consumers who have a preference for socially responsible<br />

production-but also increases costs. We consider the impact of supply chain<br />

structure on the firms’ decisions, and discuss how the supplier and consumer<br />

population characteristics combine to influence the equilibrium degree of social<br />

responsibility in the industry.<br />

4 - Responsive Pricing of Fashion Products: The Effects of Demand<br />

Learning and Strategic Consumer<br />

Mike Wei, Olin Business School, Washington University,<br />

St. Louis, MO, United States of America, weim@wustl.edu,<br />

Fuqiang Zhang, Yossi Aviv<br />

We provide a stylized Bayesian demand learning model to investigate the value of<br />

responsive pricing under strategic consumer behavior. In particular, we find that<br />

increasing market uncertainty affects the value of responsive pricing adversely<br />

due to the spread effect and the manipulation effect. Furthermore, it can be<br />

shown that the price commitment can boost the seller’s revenue substantially, and<br />

the information can be much more valuable under strategic consumers than<br />

under myopic consumers.<br />

INFORMS Phoenix – 2012<br />

89<br />

■ SB29<br />

29- North 222 A- CC<br />

Workforce Engineering<br />

Cluster: Workforce Management<br />

Invited Session<br />

Chair: Ruwen Qin, Assistant Professor, Missouri University of Science<br />

and Technology, 600 W. 14th St., 218 Engineering Management<br />

Building, Rolla, MO, 65409, United States of America, qinr@mst.edu<br />

1 - Cross-training of Team Members to Deal with Demand Mix<br />

Variation and Absenteeism<br />

Jordi Olivella, Assistant Professor, Universitat Politècnica de<br />

Catalunya, Esteve Terradas, 7, Castelldefels, 08860, Spain,<br />

jorge.olivella@upc.edu, David Nembhard<br />

The objectives of this work are: (1) To develop a method to determine the crosstraining<br />

goals of a work team in order to deal with certain levels of variation in<br />

the demand mix and absenteeism; and (2) Evaluating alternative policies of crosstraining<br />

of team members. The demand mix variation is defined by establishing a<br />

maximum time to devote to each product. To solve numerically the mathematical<br />

problem generated a selection constraint based procedure is developed.<br />

2 - Strategic Workforce Planning Models for<br />

Semiconductor Manufacturing<br />

Shrikant Jarugumilli, Sr. Operations Research Specialist, BNSF<br />

Railway, 2400 Western Center Blvd., Ft Worth, TX, 76131,<br />

United States of America, Shrikant.Jarugumilli@bnsf.com,<br />

Scott Grasman, Naiping Keng<br />

In this work, we propose an integrated framework that links the strategic<br />

workforce planning model to the operational workforce allocation models. The<br />

strategic workforce planning model enables the planners to make decisions to<br />

retain and hire workers, along with the design of worker cross-training programs<br />

based on the long-term requirements of the organization.<br />

3 - Development of a Human-based Metric Selection Protocol<br />

Gratchen Macht, Pennsylvania State University, 244 Leonhard<br />

Building, University Park, PA, 16802, United States of America,<br />

gam201@psu.edu, David A. Nembhard<br />

Relevant solutions to current complex problems require the incorporation of<br />

highly functional collaborative skills within a team-like framework. A humanbased<br />

selection protocol was developed through a mixture of technical skills and<br />

psychological profiles to address interdisciplinary teams. The results impact team<br />

formulation to improve the overall team performance.<br />

4 - Optimal Flow-line Conditions with Worker Variability<br />

Frank Bentefouet, Research Assistant, Pennsylvania State<br />

University, 1231 South Allen Street, State College, PA, 16801,<br />

United States of America, fub3@psu.edu, David Nembhard<br />

In this paper, we propose a framework to study the workforce scheduling<br />

problem in an assembly line also called flow line. We investigate the impact of<br />

within-worker and between workers variability and discuss the selection of a<br />

scheduling policy between fixed and work sharing system. We characterize the<br />

optimal switching time between workers in a system with two tasks and establish<br />

the maximum number of changes between assignments when considering a<br />

general floor shop.<br />

■ SB30<br />

SB30<br />

30- North 222 B- CC<br />

Supply Chain Risk Management<br />

Sponsor: Manufacturing & Service Oper Mgmt/iFORM<br />

Sponsored Session<br />

Chair: Zhibin (Ben) Yang, Assistant Professor, University of Oregon,<br />

1208 University of Oregon, Eugene, 97403, United States of America,<br />

zyang@uoregon.edu<br />

Co-Chair: Volodymyr Babich, Assistant Professor, McDonough School<br />

of Business, Georgetown University,37th and O Streets, NW, 546 Rafik<br />

B. Hariri Building, Washington, DC, 20057, United States of America,<br />

vob2@georgetown.edu<br />

1 - Sourcing Strategies under Supply Yield Uncertainty<br />

Guang Xiao, Washington University in St. Louis, One Brookings<br />

Drive, Campus Box 1133, St. Louis, MO, 63130, United States of<br />

America, xiaoguang@wustl.edu, Lingxiu Dong, Nan Yang<br />

We consider a one-buyer-multi-supplier system in the presence of supply yield<br />

uncertainty. We explore the impact of various supply contractual arrangements<br />

and different yield uncertainty profiles on the equilibrium supply chain<br />

performance.


SB31<br />

2 - The Impact of Cost and Quality on Illegal Goods in the<br />

Supply Chain<br />

Maqbool Dada, Professor, Johns Hopkins Carey Business School,<br />

100 International Drive, Baltimore, MD, 21202, United States of<br />

America, dada@jhu.edu, Arkadi Seidscher, Stefan Minner<br />

A manufacturer of a branded product may deter competition from parallel<br />

imports, smuggled goods or counterfeits by investing in higher quality and<br />

lowering price. A four stage model of competition is developed to examine the<br />

impact of such competition. The analysis also has implications for legal means of<br />

competition; for example, from store brands in supermarkets or generic drugs in<br />

pharmacies.<br />

3 - How To (and How Not To) Manage Supplier’s Process<br />

Improvement: Delegation, Incentives, or Audit<br />

Mehmet Gumus, Assistant Professor, McGill University,<br />

1001 Sherbrooke West, Montreal, QC, H3A1G5, Canada,<br />

mehmet.gumus@mcgill.ca, Mohammad Nikoofal<br />

In this paper, we explore the effectiveness of process improvement as a supply<br />

disruption mitigation strategy in the presence of moral hazard and adverse<br />

selection. In order to address these issues, we develop a dyadic supply chain<br />

model where both the degree of supply disruption risk and supplier’s mitigation<br />

effort are unobservable from retailer. Our analysis shows that eliminating moral<br />

hazard via monitoring has a non-monotonic effect on the screening cost.<br />

4 - Intermediated Sourcing under Supply Disruption Risk<br />

Zhibin (Ben) Yang, Assistant Professor, University of Oregon, 1208<br />

University of Oregon, Eugene, 97403, United States of America,<br />

zyang@uoregon.edu, Volodymyr Babich<br />

We analyze a model where multiple buyers decide whether to procure goods from<br />

unreliable suppliers directly or using an intermediary firm. We show that lowrevenue<br />

buyers may enjoy spill-over benefits of procurement cost reduction<br />

when high-revenue buyers choose to use the intermediary. Intermediation may<br />

also reduce system-wide product waste, by coordinating diversification efforts<br />

across buyers. These benefits have to be weighed against intermediation costs,<br />

such as double-marginalization.<br />

■ SB31<br />

31- North 222 C- CC<br />

Supply Chain Risk and Resilience<br />

Cluster: Managing Disruptions in Supply Chains<br />

Invited Session<br />

Chair: Kash Barker, Assistant Professor, School of Industrial and<br />

Systems Engineering, University of Oklahoma, 202 W. Boyd St., Rm<br />

124, Norman, OK, 73019, United States of America,<br />

kashbarker@ou.edu<br />

1 - Disruption Management during Supply Chain Disruptions<br />

Cameron MacKenzie, University of Oklahoma, 202 W. Boyd St.,<br />

Norman, OK, United States of America, cmackenzie@ou.edu,<br />

Kash Barker<br />

Many firms suffered from supply disruptions due to the recent Japanese<br />

earthquake and tsunami. We analyze these disruptions by developing a model in<br />

which several suppliers’ production facilities are rendered inoperable. Each<br />

supplier must decide whether to move production to an alternate facility or wait<br />

for its facility to reopen. If suppliers do not produce at alternate facilities, firms<br />

will need to decide how to mitigate the impacts of a supply shortage.<br />

2 - Resilient Supply-chain Network Design with Multi-sourcing<br />

Haifei Yu, PhD, Northeastern University, No.11, Lane 3,<br />

WenHua Road, Heping District,Liaoning, Shenyang, 110004,<br />

China, hfyu@mail.neu.edu.cn, Shoufeng Ji<br />

With the uncertainty risk of supply disruptions, it is critical for the supply-chain<br />

system to be resilient. We study the problem of designing a resilient supply chain<br />

network with multi-sourcing, and propose a chance-constrained programming<br />

model, and use a mixed integer linear programming to solve it. We evaluate the<br />

benefit of multi-sourcing, balance operation costs, resilience, and disruption risk<br />

by the computational experiments.<br />

3 - Prediction and Prevention of Disruptions in Supply<br />

Chain Networks<br />

Xin Chen, Assistant Professor, Southern Illinois University<br />

Edwardsville, 3079 Engineering Building, Edwardsville, IL,<br />

62026-1805, United States of America, xchen@siue.edu<br />

The objective of this research is to apply the failure mode, effects, and criticality<br />

analysis (FMECA) and graph theory to predict and prevent disruptions in supply<br />

chain networks. A network may be disrupted due to node failures. A node<br />

represents a supplier, customer, or transportation route. This research applies<br />

graph theory to model supply chain networks and uses the FMECA to identify<br />

critical nodes. A case study of a construction supply chain is analyzed to validate<br />

the methodology.<br />

INFORMS Phoenix – 2012<br />

90<br />

4 - Supply Chain Resilience<br />

Ivan Hernandez, Stevens Institute of Technology, 167 8th Street,<br />

Apt 4, Hoboken, NJ, 07030, United States of America,<br />

ihernand@stevens.edu, Jose Ramirez-Marquez, David Nowicki<br />

We present a method that allows decision makers to ensure a Supply Chain (SC)<br />

returns to a high level of performance following a contingency. We introduce the<br />

concept of SC resilience as a function of the post-event investment resources<br />

needed for the SC to “bounce back”. The concepts can be used as a guide for<br />

companies to use their long-term SC plan as a starting point, then begin to ask<br />

themselves what they would do if various contingencies occur.<br />

■ SB32<br />

32- North 223- CC<br />

Assembly Line Design and Balancing I<br />

Contributed Session<br />

Chair: Slim Daoud, Université de Technologie de Troyes,<br />

32 Rue du Palais de Justice, Troyes, 10000, France, slim.daoud@utt.fr<br />

1 - Spreadsheet Based Optimization for Cell Formation Problem<br />

Gurkan Ozturk, Assistant Professor, Anadolu University, Faculty of<br />

Engineering, Department of Industrial Eng., Eskisehir, 26555,<br />

Turkey, gurkan.o@anadolu.edu.tr, Mumin Sonmez<br />

In this study, a new hybrid algorithm based on competitive neural network and<br />

particle swarm optimization approaches is proposed to solve cell formation<br />

problem with alternative part routings. This algorithm is implemented in two<br />

spreadsheet platform: MS Excel and Google Spreadsheet. Although MS Excel<br />

faster than the Google Spreadsheet, the property of internet access of google<br />

spreadsheet presents different advantages.<br />

2 - Neuro-fuzzy-genetic Algorithm for the Robotic Assembly<br />

Lines Balancing<br />

Slim Daoud, Université de Technologie de Troyes, 32 Rue du Palais<br />

de Justice, Troyes, 10000, France, slim.daoud@utt.fr, Yalaoui<br />

Farouk, Amodeo Lionel, Chehade Hicham, Duperray Philippe<br />

We are interested in an industrial application of a robotic assembly line problem.<br />

It consists of seizing the products on a moving conveyor and placing them on<br />

different deposit points. The goal is to optimize the efficiency of the line. As in our<br />

industrial application we are bounded by the execution time, we suggest a genetic<br />

algorithm combined with a neuro-fuzzy network to solve our problem. The<br />

experimental results show the advantages and the efficiency of the developed<br />

method.<br />

3 - Balancing Mixed Model Assembly Line with Capacity Buffer<br />

Jinlin Li, Xi’an Jiaotong University, No.28, Xianning West Road,<br />

Xi’an, China, ljl1019@163.com, Jie Gao, Linyan Sun<br />

This paper investigate the design of a mixed model assembly line with capacity<br />

buffer to satisfy unstable demands. The objective is to minimize the expected<br />

labor cost, including cost for normal operation and overtime work. A mathematic<br />

model is built and a method is proposed to estimate the cost lower bound. A<br />

branch, bound and remember algorithm is developed and the numerical<br />

experiment shows that the algorithm is effective and efficient.<br />

4 - Recognition of Freeform Surface Sheet Metal Features<br />

Saied Darwish, Professor, King Saud University, Riyadah,<br />

800/11421, Saudi Arabia, darwish@ksu.edu.sa,<br />

Hammouda Mousal<br />

This paper describes the design and implementation of a system for automated<br />

feature recognition of freeform surface CAD models of stamped and notched<br />

sheet metal parts, represented in STEP AP203 format through CATIA V5.


■ SB33<br />

33- North 224 A- CC<br />

Modeling Sustainability in Supply Chains<br />

Sponsor: Manufacturing & Service Oper Mgmt/<br />

Sustainable Operations<br />

Sponsored Session<br />

Chair: Krishnan Anand, Associate Professor, University of Utah, David<br />

Eccles School of Business, Salt Lake City, UT, 84108, United States of<br />

America, k.anand@utah.edu<br />

1 - Finding and Implementing Energy Efficiency Projects in<br />

Industrial Facilities<br />

Sam Aflaki, HEC, France, aflaki@hec.fr, Paul R. Kleindorfer<br />

There are many profitable Energy Efficiency projects in many industrial<br />

enterprises that are not implemented. One of the main barriers often cited as the<br />

main culprit is lack of an internal management framework to find, value and<br />

execute these projects. Using a conceptual approach, we rely on the existing<br />

sustainable operations tools to provide such a framework. A case example of a<br />

large manufacturing site illustrates the details of this framework.<br />

2 - Closed-loop Supply Chain Design under Uncertainty<br />

Vedat Verter, Professor, McGill University, 1001 Sherbrooke St.<br />

W., Montreal, QC, H3A 1G5, Canada, vedat.verter@mcgill.ca,<br />

Wenyi Chen, Beste Kucukyazici<br />

We present a mathematical formulation for designing a closed-loop supply chain<br />

under uncertainties with regards to demand, return rate and recovery rate. The<br />

model is applied in studying a realistic problem instance that involve the<br />

production and recycling of washers and tumble dryers in Germany. We will<br />

presents the managerial insights derived from a large set of computational<br />

experiments.<br />

3 - Consumer Markets for Remanufactured Products:<br />

Empirical Evidence and Economic Models<br />

James Abbey, Pennsylvania State University, 463A Business<br />

Building, University Park, PA, 16802, United States of America,<br />

jda188@psu.edu, Dan Guide, Joseph Blackburn<br />

When considering remanufactured products, do consumers follow the typical<br />

principle of ‘cheaper is better’ or do other rules apply? Additionally, do consumer<br />

markets for remanufactured products demonstrate homogeneous price-taking<br />

behavior? This research addresses these and other questions in relation to<br />

consumer markets for remanufactured products. Insights derive from<br />

triangulation of empirical investigations and tightly coupled economic modeling.<br />

4 - Investing in Pollution Abatement Innovations under Emission<br />

Taxes and Cap-and-trade<br />

Francois Giraud-Carrier, University of Utah, David Eccles School of<br />

Business, 1645 E Campus Center Dr, Salt Lake City, UT, 84112,<br />

United States of America, f.giraud-carrier@business.utah.edu,<br />

Krishnan Anand<br />

We compare the incentives of polluting firms to invest in an innovative pollution<br />

abatement technology under two popular pollution governance structures—<br />

emission taxes and cap-and-trade. In our model, firms first decide whether to<br />

adopt the (costly) innovative technology, and then make production and<br />

abatement decisions. We compare the impact of each governance structure on<br />

firms’ pollution abatement strategies, output and profits, consumer surplus and<br />

welfare.<br />

■ SB34<br />

34- North 224 B - CC<br />

Product Achitecture and Design<br />

Contributed Session<br />

Chair: John Jung-Woon Yoo, Assistant Professor, Bradley University,<br />

1501 W. Bradley Ave., Peoria, IL, 61625, United States of America,<br />

jyoo@bradley.edu<br />

1 - Small Modular Infrastructure<br />

Caner Gocmen, Columbia Business School, 3022 Broadway,<br />

Uris Hall, 4V, New York, NY, 10027, United States of America,<br />

fgocmen13@gsb.columbia.edu, Garrett Van Ryzin, Eric Dahlgren,<br />

Klaus Lackner<br />

In many basic infrastructure industries, such as electric power generation, we<br />

have witnessed a trend of ever increasing unit size. We argue for a reversal of this<br />

trend - a radical shift to a world in which custom built technology of massive unit<br />

scale is replaced by small, modular and mass-produced units. To make this case,<br />

we develop a framework to evaluate the economics of unit scale and argue that<br />

many industries are already at a tipping point toward radically smaller unit scale.<br />

INFORMS Phoenix – 2012<br />

91<br />

2 - Strategic Linkages of Product Architecture Decisions:<br />

Organizational and Performance Implications<br />

Ujjal Mukherjee, Research Assistant, University of Minnesota,<br />

1261 Gibbs Ave., Apt G, Saint Paul, MN, 55108-1159,<br />

United States of America, mukh0067@umn.edu<br />

What are the strategic linkages to product architecture decisions and what are the<br />

organizational and performance implications of such linkages? We adopt an<br />

‘alignment’ perspective for the strategic positions, and the product architecture<br />

decisions. This frame-work is used as a basis to develop a proposed product<br />

architecture categorization and organizational architecture linkages. The<br />

framework includes the linkages ‘strategic positioning – product architectureorganization-performance’.<br />

3 - Social Network Effects on Product Line Design<br />

Dilek Gunnec, University of Maryland, 3330 Van Munching Hall,<br />

College Park, MD, 20742, United States of America,<br />

dgunnec@rhsmith.umd.edu, Subramanian Raghavan<br />

We model peer influence effects among the social network of users of products<br />

from the same product line. Influence among customers alters their utilities from<br />

the products, and therefore do not allow for an a priori preference ordering for an<br />

individual among different product profiles at the outset. We analyze product<br />

diffusion processes over the network and identify the set of products to maximize<br />

the total market share when each customer selects the product with the highest<br />

utility.<br />

4 - Performance Evaluation of Interface-based Solution Procedures<br />

for Modular Product Design<br />

John Jung-Woon Yoo, Assistant Professor, Bradley University,<br />

1501 W. Bradley Ave., Peoria, IL, 61625, United States of America,<br />

jyoo@bradley.edu<br />

In our earlier work we have proposed a collaboration system for modular product<br />

design and proposed three interface-based solution approaches, a mathematical<br />

approach based on Integer Programming, an algorithmic approach based on<br />

branch-and-bound method and, finally, a heuristic method. The first two<br />

approaches are for the optimal solution, while the last one is for a heuristic<br />

solution. In this talk, the experimental results are discussed and the performance<br />

of the three approaches is compared.<br />

■ SB35<br />

SB35<br />

35- North 225 A- CC<br />

Dynamic Pricing<br />

Sponsor: Revenue Management & Pricing<br />

Sponsored Session<br />

Chair: Ming Chen, Assistant Professor, California State University,<br />

School of Business Administration, Long Beach, CA, 90840,<br />

United States of America, Ming.Chen@csulb.edu<br />

1 - Robust Customized Pricing<br />

Elcin Cetinkaya, Doctoral Student, Lehigh University, 200 W.<br />

Packer Avenue, Bethlehem, PA, 18015, United States of America,<br />

elcin.cetinkaya@lehigh.edu, Aurelie Thiele<br />

We study robust revenue management problems when companies request bids<br />

for services but their price-response function is not known precisely. The<br />

company bidding for these contracts only knows the previous bids it submitted to<br />

those businesses and whether they were accepted or not. We show how to derive<br />

tractable mathematical models for this problem and provide insights into the<br />

optimal solution. We also document the performance of the approach in<br />

numerical experiments.<br />

2 - Joint Pricing and Inventory Decisions under Poisson<br />

Decomposition with Insights on Optimal Assortment<br />

Bacel Maddah, Associate Professor, American University of Beirut,<br />

Bliss Street, Beirut, Lebanon, bm05@aub.edu.lb, Ebru Bish,<br />

Hussein Tarhini<br />

We consider substitutable retail products in a market with logit choice, demand<br />

generated by Poisson decomposition, and a newsvendor-type supply setting. We<br />

focus on the joint pricing and inventory problem for a given assortment, under a<br />

highly accurate Taylor-like approximation. We show that the expected profit is<br />

unimodal in the price and analyze the effect of inventory on pricing. Then, with<br />

no approximation, we analyze the joint assortment and inventory problem, and<br />

derive novel insights.


SB36<br />

3 - Survey of Dynamic Pricing Research on Selling a Given<br />

Inventory over a Finite Horizon<br />

Ming Chen, Assistant Professor, California State University,<br />

School of Business Administration, Long Beach, CA, 90840,<br />

United States of America, Ming.Chen@csulb.edu<br />

We present a review of existing research on dynamic pricing problems involve<br />

selling a given amount of inventory over a finite time horizon without inventory<br />

replenishment. We classify these problems into several classes based on a number<br />

of problem attributes and summarize main findings and managerial insights.<br />

■ SB36<br />

36- North 225 B- CC<br />

New Directions in Revenue Management<br />

Sponsor: Revenue Management & Pricing<br />

Sponsored Session<br />

Chair: Omar Besbes, Columbia Business School, 3022 Broadway,<br />

New York, NY, 10027, United States of America, ob2105@columbia.edu<br />

Co-Chair: Gabriel Weintraub, Columbia Business School, 3022<br />

Broadway, New York, NY, 10027, United States of America,<br />

gyw2105@columbia.edu<br />

1 - Intertemporal Price Discrimination: Structure and Computation<br />

of Optimal Policies<br />

Ilan Lobel, New York University, Stern Business, 44 W 4th St.,<br />

New York, NY, United States of America, ilobel@stern.nyu.edu,<br />

Omar Besbes<br />

We consider the problem of a firm selling goods over time to customers with<br />

heterogeneous patience levels. We let customer valuations be correlated with<br />

their willingness-to-wait and look for a dynamic pricing policy that maximizes the<br />

long-term revenue of the firm. We prove several structural properties of the<br />

optimal pricing policy and develop a dynamic programming algorithm that<br />

computes the optimal policy in polynomial time.<br />

2 - ADP For (Very) High Dimensional Resource Allocation<br />

Vivek Farias, Massachusetts Institute of Technology, 77<br />

Massachusetts Avenue, Cambridge, MA, United States of America,<br />

vivekf@mit.edu, Dragos Florin Ciocan<br />

Due to the heterogeneous nature of the resource being allocated (impressions),<br />

online Ad Display allocation presents a challenge to traditional revenue<br />

management approaches. We present a novel ADP inspired clustering technique<br />

that allows for real time resource allocation in such problems. Since this scheme is<br />

calibrated through solving a natural, but massive linear program, we also deploy a<br />

scheme that can solve effectively arbitrarily large LPs in a decentralized manner.<br />

3 - Optimal Timing of New Product Introduction using Preliminary<br />

Market Testing<br />

Rene Caldentey, New York University, 44 West Fourth Street,<br />

New York, NY, United States of America, rcaldent@stern.nyu.edu,<br />

Victor Araman<br />

Introducing new products into the marketplace is a risky bet that manufacturers<br />

must continuously take. As a result, it is not uncommon to witness major<br />

manufacturers discontinuing a product shortly after its introduction. In this talk,<br />

we consider a seller who first tests the market and learns more about the demand<br />

before deciding whether or not to launch a product (or set of products). We also<br />

discuss current e-commerce practices that have increase companies’ ability to do<br />

such market testing.<br />

4 - Auctions Design for Online Display Advertising Exchanges<br />

Santiago Balseiro, Columbia Business School,<br />

3022 Broadway, New York, NY, 10027, United States of America,<br />

srb2155@columbia.edu, Omar Besbes, Gabriel Weintraub<br />

Ad Exchanges are emerging markets where advertisers may purchase display ad<br />

placements directly from publishers via a simple auction mechanism. Using the<br />

novel notion of a Fluid Mean Field Equilibrium we study key auction design<br />

decisions that publishers face in these markets. In particular, we provide sharp<br />

prescriptions regarding the reserve price, the allocation of impressions to the<br />

exchange versus an alternative channel, and the disclosure of viewers’<br />

information.<br />

INFORMS Phoenix – 2012<br />

92<br />

■ SB37<br />

37- North 226 A- CC<br />

Dynamic Pricing in Supply Chains<br />

Sponsor: Revenue Management & Pricing<br />

Sponsored Session<br />

Chair: Jian Li, Assistant Professor, Northeastern Illinois University,<br />

5500 N. St. Louis Ave, Chicago, IL, 60625, United States of America,<br />

j-li3@neiu.edu<br />

1 - The Inventory Billboard Effect on Information Sharing in<br />

Competing Supply Chains<br />

Zhengping Wu, Assistant Professor, Singapore Management<br />

University, 50 Stamford Road, Singapore, Singapore,<br />

zpwu@smu.edu.sg, Rong Li, Xin Wei<br />

The inventory billboard effect in operations management indicates that the<br />

increasing shelf-space allocated to a product has a positive effect on the product<br />

demand. This paper studies the billboard effect on the vertical information sharing<br />

strategy of competing supply chains in an environment with production<br />

diseconomies. We analyze how equilibrium information sharing strategy,<br />

wholesale price and retail quantity are affected by the billboard effect coefficient.<br />

2 - Price Trends in Dynamic Pricing Models<br />

Xiaowei Xu, Associate Professor, Rutgers Business School,<br />

1 Washington Park, Room 958, Newark, NJ, 07102-3122,<br />

United States of America, xiaoweix@business.rutgers.edu<br />

We consider a seller that has a limited amount of asset to liquidate in a finite time<br />

horizon. Demand signals are updated at preset time spots and the seller can adjust<br />

the product price accordingly. We offer the managerial insights of how<br />

probabilistic price trends are affected by time-varying and price-sensitive demand<br />

forms via exploring the recursive structure of the optimal pricing policy and the<br />

implied martingale decomposition.<br />

3 - Dynamic Pricing with Random Replenishment Capacity<br />

Jian Li, Assistant Professor, Northeastern Illinois University,<br />

5500 N. St. Louis Ave., Chicago, IL, 60625,<br />

United States of America, j-li3@neiu.edu, Xiaowei Xu<br />

In this research, we study the decision problem facing a retailer who sells a short<br />

seasonal product inventory in a stylized model. The retailer has an uncertain<br />

second chance to refill its inventory. We analytically derive the structure of the<br />

optimal dynamic pricing policy and procurement decisions. We also explore the<br />

properties of the optimal dynamic pricing and the expected profit function.<br />

■ SB38<br />

38- North 226 B- CC<br />

Service Innovations in the Global Marketplace<br />

Sponsor: Service Science<br />

Sponsored Session<br />

Chair: Christian Wernz, Assistant Professor, Virginia Tech, 205 Durham<br />

Hall (0118), Blacksburg, VA, 24061, United States of America,<br />

cwernz@vt.edu<br />

1 - Service Engineering – Trends, Perspectives and the<br />

Contribution to Service Science<br />

Walter Ganz, Director, Fraunhofer IAO, Nobelstr. 12, Stuttgart,<br />

70569, Germany, Walter.Ganz@iao.fraunhofer.de, Thomas Meiren<br />

A large amount of work has been done in relation to the definitions, typologies of<br />

services. It is noticeable that the development of fundamental models for services<br />

has tended to be neglected. Discussing the options of model creation as well as the<br />

simulation of services was a central topic of our expert study “MARS”. It becomes<br />

obvious that the creation of models as well as simulation has gained an<br />

importance within the last years and it could make a relevant contribution for<br />

Service Science<br />

2 - Firm Value of Product Innovation in Service Ecosystems:<br />

A Study of Smartphones<br />

Rahul Basole, Associate Director and Senior Research Scientist,<br />

Tennenbaum Institute, Georgia Institute of Technology, 75 Fifth<br />

Street NW, Suite 600, Atlanta, GA, 30308, United States of<br />

America, rahul.basole@ti.gatech.edu, Hyunwoo Park<br />

We examine the asymmetric impact of product innovation on the market value of<br />

manufacturers (e.g. device manufacturers) and service providers (e.g. mobile<br />

network operators) in the mobile service ecosystem. Our analysis is based on a<br />

comprehensive dataset comprising over 1,500 smartphones and considers the<br />

influence of product characteristics, the frequency and timing of product<br />

innovation, and the network structure of the service ecosystem. Theoretical and<br />

managerial implications are discussed.


3 - The Design of Experiential Services<br />

Uday Karmarkar, Professor, UCLA, 110 Westwood Plaza,<br />

Los Angeles, CA, 90095, United States of America,<br />

uday.karmarkar@anderson.ucla.edu, Aparupa Das Gupta,<br />

Guillaume Roels<br />

We address sequencing and resource allocation of stages in a multi-stage service<br />

encounter where customer perceptions of experience are important, as in the<br />

hospitality industry. We employ evidence from behavioral studies about how<br />

people evaluate and retain memories of experiences. We model these phenomena<br />

parsimoniously, and use the models to design service processes so as to maximize<br />

ex-post customer satisfaction.<br />

4 - Service Convergence: A New Phenomenon?<br />

Christian Wernz, Assistant Professor, Virginia Tech, 205 Durham<br />

Hall (0118), Blacksburg, VA, 24061, United States of America,<br />

cwernz@vt.edu, Pooja Thakur, Kongkiti Phusavat<br />

We investigate the phenomenon of service convergence. Service convergence is<br />

defined as the tendency of previously separate service offerings to evolve towards<br />

an integrated product. We analyzed the business strategy of a Thai hospital and<br />

identified service convergence as a result of the firm’s quality improvement and<br />

innovation initiative. We discuss how the integration of medical services with<br />

hospitality services contributed to the hospital’s success in the medical tourism<br />

industry.<br />

■ SB39<br />

39- North 226 C- CC<br />

Service Quality Evaluation and Customer Retention<br />

Sponsor: Service Science<br />

Sponsored Session<br />

Chair: Gregory Heim, Associate Professor, Mays Business School at<br />

Texas A&M University, 320 Wehner Building, 4217 TAMU,<br />

College Station, TX, 77843-4217, United States of America,<br />

gheim@mays.tamu.edu<br />

1 - Development of a Service Quality Evaluation Scheme in a<br />

Service Laboratory Environment<br />

Ryeok-Hwan Kwon, Pohang University of Science and Technology,<br />

Engineering Buliding #4-316, Hyoja-Dong, Nam-Gu, Pohang,<br />

Kyungbuk, Pohang, Korea, Republic of, rh_kwon@postech.ac.kr,<br />

Hyun-Jin Kim, Kwang-Jae Kim<br />

A virtual reality (VR) laboratory for service testing has been constructed in Korea.<br />

One issue associated with its operation is how to evaluate the quality of a service<br />

tested in a laboratory environment. We present a service quality evaluation<br />

scheme for a service laboratory environment, consisting of two parts: a repository<br />

of service evaluation criteria and a guideline to select pertinent criteria for a<br />

particular case study. The result of a case study will also be presented.<br />

2 - Factors Affecting Students’ Perceptions of Quality in<br />

Higher Education<br />

Martha Ramírez-Valdivia, Assistant Professor, Universidad de La<br />

Frontera, Avenida Francisco Salazar 01145, Temuco 4780000,<br />

Chile, marthar@ufro.cl, Favia Catrileo, Horacio Miranda<br />

This study identified which background dimensions influences student<br />

perceptions of quality in higher education. A questionnaire was applied to 27,182<br />

chilean university students; 687 responses were received, 223 valid ones. A<br />

factorial analysis verified accuracy and validity. The main findings indicate that<br />

the lecturer¥s competencies and the lecturer¥s attitude and behavior are the main<br />

determinants in the provision of quality education. The perception of the quality<br />

service is medium to low.<br />

3 - Dynamic Customer Acquisition and Retention Management<br />

Greg King, PhD Candidate, University of Michigan, Department of<br />

Industrial and Operations, Ann Arbor, MI, United States of<br />

America, gjking@umich.edu, Xiuli Chao, Izak Duenyas<br />

In consulting, finance, and other service industries, customers represent a<br />

revenue stream, and must be acquired and retained over time. In this paper, we<br />

study the resource allocation problem of a profit maximizing service firm that<br />

dynamically allocates its resources towards acquiring new clients and retaining<br />

unsatisfied existing ones. We formulate the problem as a dynamic program and<br />

characterize the structure of the optimal acquisition and retention strategy.<br />

INFORMS Phoenix – 2012<br />

93<br />

■ SB40<br />

40- North 227 A- CC<br />

Stochastic Hydro-Thermal Scheduling I<br />

Sponsor: Energy, Natural Res & the Environment/Energy<br />

Sponsored Session<br />

Chair: Steffen Rebennack, Assistant Professor of Operations Research,<br />

Colorado School of Mines, 1500 Illinois St., Golden, CO, 80401,<br />

United States of America, srebenna@mines.edu<br />

Co-Chair: Timo Lohmann, PhD Student, Colorado School of Mines,<br />

816 15th Street, Golden, CO, 80401, United States of America,<br />

tlohmann@mines.edu<br />

1 - A Dynamic Piecewise Linear SDDP Algorithm Applied to<br />

Stochastic Nonlinear Hydrothermal Scheduling<br />

Andre Luiz Diniz, Researcher, CEPEL-Brazilian Electric Energy<br />

Research Center, Av. Horacio Macedo 354, Cidade Universitária,<br />

Ilha do Fundão, Rio de Janeiro, RJ, 22220040, Brazil,<br />

diniz@cepel.br, Michel Ennes, Renato Cabral<br />

We propose dynamic piecewise linear models to represent nonlinear constraints<br />

and objective function in stochastic multi-stage convex optimization problems<br />

solved by stochastic dual dynamic programming (SDDP). The proposed approach<br />

provides valid cuts and convergence bounds and yields more accurate results as<br />

compared to standard piecewise linear models, in lower CPU times. We present<br />

results of its application for the generation planning of the real large-scale<br />

Brazilian hydrothermal system.<br />

2 - Representation of Nonconvexities in Stochastic Dual Dynamic<br />

Programming (SDDP)<br />

Fernanda Thomé, Research Engineer, PSR, Praia de Botafogo<br />

228/1701-A, Rio de Janeiro, RJ, 22250145, Brazil,<br />

fernanda@psr-inc.com, Mario Veiga Pereira, Sérgio Granville,<br />

Marcia Fampa<br />

This work describes an extension of the SDDP algorithm to represent<br />

nonconvexities such as variation of hydro production coefficient with storage and<br />

thermal unit commitment. The proposed methodology uses a Lagrangean<br />

relaxation on the water balance equation to generate convex Benders cuts during<br />

the backward recursion phase, with a special procedure to find the optimal<br />

multiplier. The approach will be illustrated with a realistic hydrothermal<br />

scheduling problem.<br />

3 - Optimizing Trading Decisions for Hydro Storage Systems using<br />

Approximate Dual Dynamic Programming<br />

Nils Löhndorf, Vienna University of Economics and Business,<br />

Nordbergstr 15/3/A, Vienna, 1090, Austria,<br />

nils.loehndorf@wu.ac.at, David Wozabal, Stefan Minner<br />

Optimal operation of hydro storage systems in electricity markets is a complex<br />

stochastic optimization problem. We formulate this problem as a Markov decision<br />

process where a stochastic mixed-integer program is solved in each time period.<br />

To find a near-optimal policy, we propose a solution approach that computes a<br />

polyhedral approximation of the value function. We describe how we applied the<br />

approach to optimize the operation of a real-world hydro storage system in the<br />

Austrian Alps.<br />

■ SB41<br />

41- North 227 B- CC<br />

Regulation in Energy<br />

Contributed Session<br />

SB41<br />

Chair: Eric O’Rear, Graduate Student, Purdue University,<br />

403 W. State Steet, West Lafayette, IN, 47907, United States of America,<br />

eorear@purdue.edu<br />

1 - A Decision Support Tool for Evaluating Regional Greenhouse<br />

Gas Emission Reduction Strategies<br />

Rick Olson, University of San Diego, 5998 Alcala Park, San Diego,<br />

CA, 92110, United States of America, r_olson@sandiego.edu,<br />

Scott Anders, Andrew Narwold, Nilmini Silva-Send<br />

Cities and counties planning policies to meet GHG reduction goals often focus on<br />

the direct impact of specific policy changes, e.g. increasing the use of mass transit.<br />

The interactions between factors, such as mass transit and telecommuting, are<br />

more difficult to understand. The paper presents a DSS that can be used by<br />

regional planners to develop strategies for meeting GHG reduction targets while<br />

considering the relationships between factors and the costs of the policies.


SB42<br />

2 - Regulated Design & Pricing in the New Vehicle Market<br />

William Morrow, Assistant Professor, Iowa State University,<br />

2104 Black Engineering Building, Ames, IA, 50011-2161,<br />

United States of America, wrmorrow@iastate.edu, Josh Mineroff,<br />

Kate S. Whitefoot<br />

Regulations influence vehicle design and pricing. However, few models of policy<br />

impacts include strategic design decisions in response to regulation. This talk<br />

describes simulation of equilibrium design and pricing decisions under regulation.<br />

Examples are given for the new vehicle market and associated fuel economy<br />

standards. Our results demonstrate that simulations that neglect strategic<br />

behavior may overestimate the effectiveness of current policy approaches.<br />

3 - The Rebound Effect and its Implications on Obama’s Plan for a<br />

Clean Energy Future<br />

Eric O’Rear, Graduate Student, Purdue University, 403 W. State<br />

Steet, West Lafayette, IN, 47907, United States of America,<br />

eorear@purdue.edu, Wallace Tyner, Kemal Sarica<br />

Our paper will compare the impacts of Obama’s modifications to CAF…<br />

standards, with a more efficient carbon tax generating a similar level of CO2<br />

reductions. Further, we intend to capture the impacts of the “rebound effect”<br />

phenomenon associated with a mandate for a higher fuel economy on the U.S.<br />

energy system. We utilize the U.S. EPA MARKAL model - a bottom-up, linear<br />

programming (LP), partial equilibrium model – to replicate and compare the<br />

policies aligned with our interests.<br />

4 - Optimal Number of Certificates to be Issued in Emission<br />

Markets<br />

Cristian Pelizzari, University of Brescia, Contrada Santa Chiara, 50,<br />

Brescia, 25122, Italy, pelizcri@eco.unibs.it, Falbo Paolo<br />

The price of allowances in the EU ETS is linked to the value of the expected<br />

penalty for the CO2 produced in excess by diverse economic players. Too severe<br />

environmental policies cause a rise in the price of allowances. The compliance of<br />

such objectives can increase production costs causing inflation and loss of<br />

competitiveness. A stochastic programming model is advanced where the<br />

regulatory authority trades-off economic growth with environmental targets,<br />

influencing the choices of the players by means of the number of allowances to be<br />

issued.<br />

■ SB42<br />

42- North 227 C- CC<br />

Tactical Issues in Freight Transportation<br />

Contributed Session<br />

Chair: Mihalis Golias, University of Memphis, 104 Engineering Science<br />

Bldg, 3815 Centr, Memphis, 38152, United States of America,<br />

mgkolias@memphis.edu<br />

1 - Model Slection for Shipper’s Mode Coice<br />

Subhro Mitra, Assistant Professor, University of North Texas,<br />

University Hills Blvd., Dallas, TX, 75241, United States of America,<br />

subhro.mitra@unt.edu, Ali S. Shaqlaih<br />

This paper presents discrete choice models developed to determine the probability<br />

of mode choice between railroad and truck, based on revealed preference data.<br />

Utility functions are formulated using the attributes of the modes, shippers and<br />

interaction between the two. The choice probability is initially estimated<br />

assuming the random component to have a logit distribution. The model is<br />

further developed assuming the stochastic component to have heteroscedastic and<br />

probit distribution.<br />

2 - Efficient Heuristic for Auto-carrier Loading Problem<br />

Saravanan Venkatachalam, Research Associate, Texas A&M<br />

University, 304A Fermier Hall, 3367 TAMU, College Station, TX,<br />

77843, United States of America, saravanan@entc.tamu.edu,<br />

Arunchalam Narayanan, Bimal Nepal<br />

This belongs to a special group of logistics problem, as it needs solution for two<br />

NP-hard subproblems, namely routing and loading. There are several efficient<br />

methods for the routing part, but very few for the loading aspect. Existing<br />

methods in literature concentrate on the cost of loading and reloading and<br />

approximate the geometric, weight, and mechanical constraints of the vehicles.<br />

We demonstrate the application of a new heuristic which incorporates all these<br />

loading constraints.<br />

3 - Load Mixing with Freight Due Dates<br />

Sarah Root, Assistant Professor, University of Arkansas,<br />

4207 Bell Engineering Center, Fayetteville, AR, 72701,<br />

United States of America, seroot@uark.edu, Crystal Wilson<br />

The underutilization in trucking leads to nearly 5 billion gallons of wasted fuel<br />

annually. One way to recapture part of this waste is to use collaborative logistics.<br />

This research focuses on one specific aspect of collaborative logistics: load mixing.<br />

Load mixing is the idea of mixing two or more items of different weights in the<br />

INFORMS Phoenix – 2012<br />

94<br />

same container to reduce the number of trucks needed. In this research we<br />

explore the impact of product due dates on the mixing of commodities to more<br />

utilize trucks. We propose heuristics to solve this problem, and present<br />

computational results from this work.<br />

4 - Cost-stable Truck Scheduling at a Cross-dock Facility with<br />

Unknown Truck Arrivals<br />

Mihalis Golias, University of Memphis, 104 Engineering Science<br />

Bldg, 3815 Centr, Memphis, 38152, United States of America,<br />

mgkolias@memphis.edu, Dincer Konur<br />

We study a cross-dock operator’s truck scheduling problem at inbound doors in<br />

case of unknown truck arrival times. Due to uncertainty of truck arrivals, a<br />

scheduling strategy is defined as a schedule with low variation levels. A biobjective<br />

optimization problem is formulated and we discuss a genetic algorithm<br />

based heuristic to find Pareto efficient schedules. The proposed approach is<br />

compared to first-come-first-served policies.<br />

■ SB43<br />

43- North 228 A- CC<br />

RAS Problem Solving Competition<br />

Sponsor: Railway Applications<br />

Sponsored Session<br />

Chair: Kamalesh Somani, Manager Operations Research, CSX<br />

Transportation, 500 Water St, Jacksonville, FL, 32202,<br />

Kamalesh_Somani@csx.com<br />

1 - Movement Planner Algorithm Design for Dispatching on<br />

Multi-Track Territories<br />

Kamalesh Somani, Manager Operations Research, CSX<br />

Transportation, 500 Water St., Jacksonville, FL, 32202,<br />

Kamalesh_Somani@csx.com<br />

A dispatcher’s task is to give track authorities to trains to maximize overall system<br />

efficiency while abiding by a number of business rules. This is done by deciding<br />

which train takes the siding when two trains traveling in opposite directions meet<br />

each other, or when a faster train is to overtake the leading slower train. They<br />

must also decide on the departure and hold times at the yard where train<br />

originate terminate or stop for work events. The three finalists will compete at<br />

this session.<br />

■ SB44<br />

44- North 228 B- CC<br />

Topics in Supply Chain Management<br />

Contributed Session<br />

Chair: Tracy Johnson-Hall, Assistant Professor, Mason School of<br />

Business, College of William & Mary, P.O. Box 8795, Williamsburg, VA,<br />

23187-8795, United States of America, tdjohns@clemson.edu<br />

1 - Isomorphism Pressures and Management Support: An<br />

Empirical Investigation in Supply Chain Security<br />

Guanyi Lu, PhD Candidate, Mays Business School at Texas A&M<br />

University, 320N, 4217 TAMU, College Station, TX, 77843-4217,<br />

United States of America, glu@mays.tamu.edu,<br />

Xenophon Koufteros<br />

This study examines the antecedents and consequences of supply chain security<br />

practices. Data analyses based on 193 U.S. firms suggest that only normative and<br />

performance pressures have a sizable effect on top management support toward<br />

security (TMS). The results also show that TMS affects proactive and contingency<br />

planning which have strong positive effects on security performance.<br />

2 - Motivation of Time Compression Diseconomies on Transitory<br />

Network Collaborations<br />

Adrian Tan, PhD Candidate, Wilfrid Laurier University,<br />

75 University Avenue West, Waterloo, ON, N2L 3C5, Canada,<br />

tanx1410@mylaurier.ca, Hamid Noori<br />

Time-based competition is increasingly used across multiple industries as a basis<br />

for strategic advantage. However, the challenge of time compression diseconomies<br />

constraint companies from building internal resources for competitive purposes as<br />

rapidly as might be desirable. An empirical study to assess if companies can meet<br />

the challenge by engaging in transitory network collaborations is presented.


3 - Time to Recall: A Duration Analysis Model of Recall Strategies<br />

and Effectiveness<br />

Tracy Johnson-Hall, Assistant Professor, Mason School of Business,<br />

College of William & Mary, P.O. Box 8795, Williamsburg, VA,<br />

23187-8795, United States of America, tdjohns@clemson.edu,<br />

Manpreet Hora, Aleda Roth<br />

We study the role of supply chain characteristics and strategies adopted by firms<br />

during product recalls and their association with time to recall for perishable<br />

goods, specifically food products. We employ a duration analysis to examine this<br />

association. We discuss our results and their implications for firms, consumers and<br />

policy-makers.<br />

4 - Order Quantity Variability in Perishable Product Supply Chains<br />

Stefan Minner, Professor, Technische Universitat München, TUM<br />

School of Management, Arcisstr 21, Munich, 80333, Germany,<br />

stefan.minner@tum.de, Sandra Transchel<br />

We analyze orders for perishable products under customer reactions to stockouts<br />

and inventory issuing policies. Variability of order quantities is lower than<br />

demand variability and implies a reduced bullwhip effect. We show that different<br />

combinations of stockout and issuing policies exhibit different order quantity<br />

variability with increasing service level and discuss a choice game where supplier<br />

and retailer can choose between the available options of stockout and depletion<br />

policy.<br />

■ SB45<br />

45- North 229 A- CC<br />

JFIG Paper Competition II<br />

Sponsor: Junior Faculty Interest Group<br />

Sponsored Session<br />

Chair: Esra Buyuktahtakin, Assistant Professor, Wichita State<br />

University, IME Department, Wichita, KS, United States of America,<br />

esra.b@wichita.edu<br />

1 - JFIG Paper Competition<br />

Esra Buyuktahtakin, Assistant Professor, Wichita State University,<br />

IME Department, Wichita, KS, United States of America,<br />

esra.b@wichita.edu<br />

Papers are submitted for this year’s JFIG paper competition, and each one is<br />

evaluated based on the importance of the topic, appropriateness of the research<br />

approach, and the significance of research contribution. In this session, finalistsselected<br />

in two rounds of review, will present their papers. For the selected<br />

finalists and the abstracts of the selected papers, please refer to the online<br />

program.<br />

■ SB46<br />

46- North 229 B- CC<br />

Organizational and Industry Renewal (II): Legitimacy,<br />

Social Norms, and Environmental Dynamics<br />

Sponsor: Organization Science<br />

Sponsored Session<br />

Chair: Andreas Schwab, Associate Professor, Iowa State University,<br />

3315 Gerdin, Ames, IA, 50011, United States of America,<br />

aschwab@iastate.edu<br />

1 - The Entrepreneur as David on Horseback<br />

Joseph Broschak, Associate Professor, University of Arizona,<br />

Eller College of Management, Department of Management &<br />

Organizations, Tucson, AZ, 85721, United States of America,<br />

broschak@email.arizona.edu, Kenneth Koput<br />

We investigate the role of social identity, information sources, and networks on<br />

new technology adoption. In the horse industry, the horseshoe is a pathdependent<br />

technology. Most horses are shod with the steel keg shoe that has been<br />

the dominant design since the 1800s, despite widespread changes in how horses<br />

are owned, kept, and used, and alternative shoe designs. Using survey data of<br />

horse owners, we explore how different social influence variables affected<br />

technology adoption decisions.<br />

INFORMS Phoenix – 2012<br />

95<br />

2 - When Practices Diffuse in a Bubble: Reverse Mergers and the<br />

Internet Wave<br />

Peggy Lee, WP Carey-ASU, 300 E. Lemon St., Tempe, 85287,<br />

United States of America, Peggy.Lee@asu.edu, Ivana Naumovska,<br />

Edward Zajac<br />

We theoretically and empirically examine the diffusion process in a bubble<br />

context. In doing so, we synthesize information-based theories of imitation with<br />

institutional theory to explain the growth and decline of reverse mergers (RM) of<br />

internet firms during the time of the internet wave (1998-2000). Our results<br />

show a clear two-stage pattern, with early RMs done by established firms, and<br />

late RMs done by fledgling firms. We also find evidence of an early mover<br />

advantage.<br />

3 - The Dynamic Mdel of Onership Hterogeneity and Corporate<br />

Social Responsibility<br />

Nai Hua Wu, Texas A&M University, 4221 TAMU, College Station,<br />

TX, 77843, United States of America, nwu@mays.tamu.edu,<br />

David Sirmon<br />

Research in corporate social responsibility (CSR) has focused mainly on<br />

managerial discretion or stakeholders. We intend to fill the gap by addressing CSR<br />

from the corporate governance perspective, specifically, the effect of ownership<br />

heterogeneity. Based on multiple agency theory, we predict that dedicated<br />

institutional owners and family owners are positively related to CSR performance,<br />

whereas transient institutional owners have negative influence. Our initial results<br />

support our predictions.<br />

4 - Redirecting Attention: Overcoming the Illegitimacy Discount<br />

Eric Yanfei Zhao, University of Alberta, 2-24 Business Building,<br />

U. of Alberta Business School, Edmonton, AB, T6G 2R6, Canada,<br />

ericy.f.zhao@gmail.com, Michael Lounsbury<br />

How can organizations spanning rigid categories solve the dilemma of sameness<br />

and difference and gain attention and favorable evaluation from audiences? In<br />

this paper, we argue that organizations can deploy cultural resources such as<br />

name to overcome audience inattention and legitimacy deficit due to category<br />

spanning. We tested and found support for this proposition using a sample of<br />

films released in the U.S. market between 1982 and 2007.<br />

■ SB47<br />

SB47<br />

47- North 230- CC<br />

Traffic Control Schemes and Application I<br />

Sponsor: Transportation Science & Logistics/ Intelligent<br />

Transportation Systems (ITS)<br />

Sponsored Session<br />

Chair: Yang Cheng, Research Associate, University of Wisconsin-<br />

Madison, 2204 Engineering Hall, Madison, WI, 53706,<br />

United States of America, cheng8@wisc.edu<br />

1 - Equity Based Real Time Traffic Signal Control at Network Level<br />

using Historical Delay Information: An Application of<br />

Vehicle-to-Infrastructure (V2I) Communication<br />

H. M. Abdul Aziz, PhD Student, Purdue University, 150 Arnold<br />

Drive, Apt15, West Lafayette, IN, 47906, United States of America,<br />

haziz@purdue.edu, Satish Ukkusuri<br />

The efficiency of signal control schemes are often evaluated based on aggregate<br />

system measures only. However, efficiency does not guarantee the equity<br />

(fairness) of the system. This research proposes a signal control scheme that<br />

assures fairness (in terms of experienced intersection delay due to signal control)<br />

across the users of the system. The signal control scheme uses the historical delay<br />

information along the entire trip of the users and we propose a vehicle-toinfrastructure<br />

communication based framework for its implementation in the real<br />

world.<br />

2 - Large Scale Traffic Signal Control: A Simulation-based<br />

Approach<br />

Carolina Osorio, Assistant Professor, Massachusetts Institute of<br />

Technology, Room 1-232, 77 Massachusetts Avenue, Cambridge,<br />

MA, 02139, United States of America, osorioc@mit.edu,<br />

Linsen Chong<br />

We propose a simulation-based optimization algorithm that efficiently solves large<br />

scale traffic signal control problems. The method is based on a metamodel<br />

approach that combines information from a detailed yet inefficient traffic<br />

simulator with information from a highly efficient and scalable macroscopic traffic<br />

model. We efficiently solve a signal control problem for the entire Swiss city of<br />

Lausanne, and derive signal plans that reduce network-wide trip travel times.


SB48<br />

3 - Intersection Signal Optimization using Queue Length Estimation<br />

Yang Cheng, Research Associate, University of Wisconsin-Madison,<br />

2204 Engineering Hall, Madison, WI, 53706, United States of<br />

America, cheng8@wisc.edu, Jeff Ban, Bin Ran<br />

By modern traffic detection technologies, traffic condition data would have higher<br />

resolution in time and space, which is especially valuable for the interrupted<br />

traffic on signalized intersections. The queue length can be estimated more easily<br />

and accurately. Therefore, this study proposes a new signal control optimization<br />

method based on queue information to improve corridor coordination. The<br />

simulation results indicate that this approach has better performance than<br />

traditional control methods.<br />

4 - An Optimal Lane-based Signal Merge Control Model for<br />

Freeway Work Zone Operations<br />

Yue Liu, University of Wisconsin-Milwaukee, P.O. Box 784,<br />

Milwaukee, WI, 53201, United States of America,<br />

liu28@uwm.edu, Jing Mao<br />

This paper presents a dynamic control model for optimizing lane-based signal<br />

merge (LBSM) operations at freeway work zones. The control objective is to<br />

maximize the throughput. GA is employed to solve the model. Results reveal that<br />

the proposed method yields much better performance than traditional merge<br />

strategies under heavy traffic conditions.<br />

■ SB48<br />

48- North 231 A- CC<br />

Integrated Supply Chain Design<br />

Sponsor: Transportation Science & Logistics/ Freight Transportation<br />

& Logistics<br />

Sponsored Session<br />

Chair: Maged Dessouky, Professor, University of Southern California,<br />

University Park Campus, Los Angeles, CA, 90007,<br />

United States of America, maged@usc.edu<br />

1 - Near-optimal Transportation and Fair Cost Allocation in an<br />

Agricultural Supply Chain with Perishable Products<br />

Christine Nguyen, University of Southern California,<br />

Los Angeles, CA, United States of America, nguyen7@usc.edu,<br />

Alejandro Toriello, Maged Dessouky<br />

We consider an agricultural supply chain where several suppliers consolidate<br />

transportation of a perishable product to achieve economies of scale. Using<br />

industry data from California flower growers, we compare a practical greedy onestep<br />

lookahead policy against optimal solutions computed from a dynamic<br />

program, and determine whether transportation costs can be allocated fairly<br />

among the suppliers.<br />

2 - Integrated Supply Chain Network Design: Location,<br />

Transportation, Routing and Inventory Decisions<br />

Mingjun Xia, Arizona State University, 1718 S Jentilly Lane,<br />

APT 204, Tempe, AZ, 85281, United States of America,<br />

Mingjun.Xia@asu.edu, Ronald Askin<br />

We propose a novel model to simultaneously optimize location, allocation,<br />

transportation, inventory and routing decisions in a stochastic multi-product<br />

supply chain system. Each producer provides a unique product. Each retailer has<br />

independent, random demand for multiple products. Consolidation and<br />

distribution facilities may be constructed to reduce shipment costs and increase<br />

the frequency of economical shipments. Heuristics are developed to solve largesize<br />

scale instances of the problem.<br />

3 - Integrated Planning of Supply Chain Layout and Transportation<br />

Infrastructure Rehabilitations<br />

Leila Hajibabai, University of Illinois at Urbana-Champaign, 205 N<br />

Mathews Avenue, Room 3142, Urbana, IL, 61801, United States of<br />

America, leila.hajibabai@gmail.com, Yun Bai, Yanfeng Ouyang<br />

Expansion of supply chains induces considerable freight shipments between<br />

supply/demand points and intermediate facilities, which significantly accelerate<br />

highway pavement deterioration. This paper presents an analytical method to<br />

simultaneously design the supply chain as well as the pavement rehabilitation<br />

plans, which determines the optimum number and location of facilities, shipment<br />

routes, and pavement rehabilitation intensity and frequency.<br />

4 - A Production Function-Based Empirical Analysis of Distribution<br />

Networks<br />

Donald Warsing, Associate Professor, North Carolina State<br />

University, 2346 Nelson Hall, Raleigh, NC, 27695, United States of<br />

America, don_warsing@ncsu.edu, Michael Kay, Christian Rossetti<br />

Using a number of public data sources, we compare distribution networks in the<br />

continental U.S. across several industry sectors. We gather data on, and/or<br />

INFORMS Phoenix – 2012<br />

96<br />

compute from base-level data, a number of independent variables that we use as<br />

inputs to a cost function for each DC in each industry data set. This cost function<br />

serves as an important means of analyzing the variance in the input data and cost<br />

data. We present insights regarding differences in distribution strategies across<br />

industries.<br />

5 - Designing LTL Load Plans to Mitigate Impact of Transit<br />

Time Variability<br />

Yu Zhang, PhD Student, Georgia Institute of Technology,<br />

765 Ferst Dr NW, Atlanta, GA, 30339, United States of America,<br />

zhangyu@gatech.edu, Alan Erera<br />

We develop a method to design robust load plans for LTL carriers in order to<br />

mitigate the cost impacts of transit time variability. Load plan candidates are<br />

generated based on optimizing operations assuming that transit times take<br />

expected values, and then evaluated and refined by Monte Carlo simulation. The<br />

proposed method is applied to a case study which is built based on terminal and<br />

shipment data from a national LTL carrier.<br />

■ SB49<br />

49- North 231 B- CC<br />

Joint Session TSL/SPPSN: Networks and<br />

Emergency Response<br />

Sponsor: Transportation Science & Logistics & Public Programs,<br />

Service and Needs<br />

Sponsored Session<br />

Chair: Halit Uster, Industrial and Systems Engineering, Texas A&M<br />

University, College Station, TX, United States of America,<br />

uster@tamu.edu<br />

1 - A Multi-objective Integrated Approach for Emergency<br />

Response Network Design<br />

Jyotirmoy Dalal, Texas A&M University, 3131 TAMU, College<br />

Station, TX, 77843, United States of America,<br />

jyotirmoy.dalal@gmail.com, Halit Uster<br />

We consider an emergency response network design problem to determine supply<br />

locations and flows required in a large scale evacuation setting. We develop a<br />

multi-objective optimization model with generalized cost structures and<br />

proximity requirements. We present an epsilon-Costraint based approach for<br />

generating the efficient frontier and the computational results, demonstrating the<br />

efficiency of the method.<br />

2 - Network Design for Emergency Response<br />

Jianing Zhi, University of Alabama, 300 Alston Hall, Tuscaloosa,<br />

AL, 35487, United States of America, jzhi@crimson.ua.edu,<br />

Burcu Keskin, Sharif Melouk<br />

We investigate a multi-period ambulance location planning problem to minimize<br />

total cost while maintaining acceptable response times. The network consists of<br />

supply centers, responder and incident locations, and hospitals. We propose two<br />

models: 1) all incidents require service in the period in which they occur, and 2)<br />

incident servicing delays are allowed but with penalty. Through experimentation,<br />

we compare these two models in terms of service quality, response time, and cost.<br />

3 - Resilience in Passenger Transportation Networks<br />

Reza Faturechi, PhD Candidate, University of Maryland, 1173<br />

Glenn L. Martin Hall, College Park, MD, 20742, United States of<br />

America, reza@umd.edu, Elise Miller-Hooks<br />

A bi-level stochastic program with equilibrium constraints is presented for<br />

assessing and optimizing resilience of passenger transportation networks. At the<br />

upper level, preparedness actions are taken to enhance the network or facilitate<br />

response actions, and response actions are taken post-disaster to restore system<br />

capacity. At the lower level, a partial user equilibrium is sought in which<br />

passengers choose their routes to minimize travel time given post-disaster system<br />

performance.<br />

4 - Logistics Planning for Restoration of Network Connectivity<br />

After a Disaster<br />

Sibel Salman, Koc University, Rumeli Feneri Yolu, Sariyer,<br />

Istanbul, 34450, Turkey, ssalman@ku.edu.tr, Ayse Nur Kibar<br />

After a disaster, damaged roads should be repaired/unblocked by a fleet of<br />

machinery initially positioned in a depot to restore highway connectivity. We<br />

define a selective arc routing problem to find the walk of k vehicles with<br />

minimum time to reach connectivity. We provide a flow-based mixed integer<br />

programming model. We consider Istanbul’s highway and determine the number<br />

of machinery and their initial locations under different road damage scenarios for<br />

earthquake preparedness.


■ SB50<br />

50- North 231 C- CC<br />

Raytheon Military Defense Applications<br />

Sponsor: Military Applications<br />

Sponsored Session<br />

Chair: George Mayernik, Raytheon Integrated Defense Systems,<br />

225 Presidential Way, Mailstop 27/2430b, Woburn, MA, 01801,<br />

United States of America, george_e_mayernik@raytheon.com<br />

1 - Operations Analysis of a Precision Tracking Space System<br />

(PTSS) for Phased Adaptive Approach (PAA)<br />

Daniel Wilson, Senior Principal Systems Engineer, Raytheon<br />

Integrated Defense Systems, 225 Presidential Way, Mailstop<br />

27/2317D, Woburn, MA, 01801, United States of America,<br />

Daniel.D.Wilson@raytheon.com<br />

The Precision Tracking Space System (PTSS) is in concept development to provide<br />

tracking for the Phased Adaptive Approach (PAA). The Space Tracking<br />

Surveillance System (STSS) demonstrated the value of Low Earth Orbit (LEO)<br />

satellites to the Ballistic Missile Defense System (BMDS). Quality of Service (QoS)<br />

metrics are being used as analytics to develop traceability from performance<br />

specifications to the mission effectiveness, system risk, and affordability of<br />

alternative BMDS architectures.<br />

2 - Deployment Concerns and Battle Management Scheduling of<br />

Unmanned Aerial Systems<br />

Jeffrey Schvey, Raytheon, 235 Presidential Way,<br />

Woburn, MA, 01801, United States of America,<br />

Jeffrey_E_Schvey@raytheon.com, George Blaha<br />

In this talk, we present an overview of operations studies using a decentralized<br />

network of airborne sensors to provide missile defense engagement support. We<br />

consider deployment concerns such as basing logistics and target area coverage, as<br />

well as sensor resource scheduling during engagements to maximize system<br />

effectiveness. Results for various deployment strategies and sensor scheduling<br />

techniques are shown.<br />

3 - Additional Ballistic Missile Defense (BMD) Considerations in a<br />

Raid Environment<br />

George Mayernik, Raytheon Integrated Defense Systems, 225<br />

Presidential Way, Mailstop 27/2430b, Woburn, MA, 01801,<br />

United States of America, george_e_mayernik@raytheon.com,<br />

John Krasnadevich, Michael McGowan<br />

Recent USA Missile Defense Agency studies have involved defense of regions<br />

against multiple ballistic missile threats arriving within a specified period of time.<br />

This paper characterizes the key factors related to BMD against a raid of threats<br />

and subsequent impact on defense resources. The effect of raid size and density is<br />

shown including defense systems effectiveness in mitigating stressing raid<br />

conditions. Radar/engagement timelines and defended areas for a scenario are<br />

presented.<br />

■ SB51<br />

51- North 232 A- CC<br />

Technology Solutions for Soldier Support<br />

Sponsor: Military Applications<br />

Sponsored Session<br />

Chair: Tom Turner, Concurrent Technologies Corp., 747 River Road,<br />

Hollis Center, ME, 04042, United States of America, turnert@ctc.com<br />

1 - A Proposed Analytic Method for Predicting IED Emplacements<br />

Johnathon Dulin, Concurrent Technologies Corporation, 771<br />

Fairdale Ct, Castle Rock, CO, 80104, United States of America,<br />

dulinj@ctc.com<br />

The proliferation of Improvised Explosive Devices (IEDs) over recent years has<br />

spawned many efforts to mitigate their effects or disrupt networks; much less<br />

attention has been given to predicting emplacement. Observed environmental<br />

anomalies may suggest an IED, but improved operational planning can help keep<br />

personnel out of harm’s way. By combining the strategic planning of game theory<br />

with the policy optimization of MDPs, we have the framework for a new<br />

approach in predicting IED emplacements.<br />

2 - Representing the Power and Energy Needs of Today’s Soldiers<br />

in Modeling and Simulation<br />

Dan Rice, Technology Solutions Experts, Inc., 209 West Central St.,<br />

Suite 300, Natick, MA, United States of America,<br />

daniel.rice@tseboston.com, Louisa Katlubeck, Adam Peloquin,<br />

Cortney Eldridge, Steven Yuhaski<br />

Each piece of equipment carried increases a Soldier’s load weight, potentially<br />

impacting performance and safety. Technology Solutions Experts, Inc. (TSE) used<br />

INFORMS Phoenix – 2012<br />

97<br />

simulation tools to study the tradeoff between Soldier encumbrance and task<br />

performance. TSE created a model and Monte Carlo simulation to study the<br />

power requirements related to a Soldier’s electronic equipment load weight to<br />

improve the ability to identify critical relationships between Soldier, equipment,<br />

and operational environment.<br />

3 - The Operational Readiness Level Metric for<br />

Technology Development<br />

Kenneth Donovan, Lockheed Martin Fellow, Lockheed Martin,<br />

1801 State Route 17C, MD 0532, Owego, NY, 13827,<br />

United States of America, ken.b.donovan@lmco.com<br />

Operational Readiness Level (ORL) is a proposed metric for assessing the<br />

operational maturity of a technology during the development cycle. ORL<br />

addresses a limitation of the Technology Readiness Level (TRL) metric that<br />

measures the technical maturity of an item, rather than the operational use. ORL<br />

requires early verification of the operational usage of a technology solution,<br />

thereby guiding technology development to produce items that benefit the user.<br />

Copyright 2012 Lockheed Martin Corporation.<br />

■ SB52<br />

52- North 232 B- CC<br />

ENRE Award Session<br />

Sponsor: Energy, Natural Res & the Environment/Energy<br />

Sponsored Session<br />

Chair: Juan Pablo Vielma, University of Pittsburgh,<br />

1043 Benedum Hall, 3700 O’Hare Street, Pittsburgh, PA, 15261,<br />

United States of America, jvielma@pitt.edu<br />

1 - ENRE Student Award: More to Follow<br />

Juan Pablo Vielma, University of Pittsburgh, 1043 Benedum Hall,<br />

3700 O’Hare Street, Pittsburgh, PA, 15261,<br />

United States of America, jvielma@pitt.edu<br />

This session includes presentations by the winners of the 2012 student travel<br />

award and best publications in energy, natural resources and the environment. In<br />

addition the following 2011 awards will be given: -Bistra Dilkina, Best Paper<br />

Award in Forestry Sponsored Sessions; -Rodolfo Carvajal, Best Paper Award in<br />

Environment and Sustainability Sponsored Sessions; - Gonzalo Munoz and Donal<br />

O’Sullivan, Best Paper Awards in Mining Sponsored Sessions.<br />

■ SB53<br />

SB53<br />

53- North 232 C- CC<br />

Stochastic Programming in Energy<br />

Sponsor: Energy, Natural Res & the Environment/Energy<br />

Sponsored Session<br />

Chair: Asgeir Tomasgard, Professor, Norwegian University of Science<br />

and Technology, Alfred getz vei 3, Trondheim, 7491, Norway,<br />

asgeir.tomasgard@iot.ntnu.no<br />

1 - The Optimization Problem for a SmartGrid Aggregator with<br />

Multiple Markets for Flexibility<br />

Stig Ottesen, PhD Candidate, Norwegian University of Science and<br />

Technology, Alfred getz vei 3, Trondheim, 7491, Norway,<br />

stig.ottesen@ncesmart.com, Asgeir Tomasgard<br />

More dynamics in the power systems lead to an increasing need for operational<br />

flexibility. Traditionally only generators and large consumers have access to<br />

markets where flexibility is valued. A SmartGrid aggregator may open such<br />

markets also for demand side participation. This paper describes the aggregator<br />

role and its possible business opportunities in current market regime. A<br />

mathematical formulation of the aggregator’s optimization problem is given<br />

covering different time horizons.<br />

2 - Long Term Capacity Equilibria under Risk: A Stochastic LP<br />

Approach Extending MARKAL<br />

Daniel Ralph, University of Cambridge Judge Business School,<br />

Trumpington Street, Cambridge, CB2 1AG, United Kingdom,<br />

d.ralph@jbs.cam.ac.uk, Yves Smeers<br />

Linear Programming, LP, is standard for modelling long term capacity equilibria,<br />

eg, MARKAL for electricity capacity, given Perfect Competition, PC. Uncertainty<br />

can be handled via expectations, ie, stochastic LP. We extend this to give an<br />

economic market interpretation of system capacity planning under risk aversion<br />

(Coherent Risk Measures). Namely, stochastic LP can be used to model capacity<br />

equilibria under risk assuming PC and financial securities are traded in a<br />

Complete Risk Market.


SB54<br />

3 - Optimal Fuel Switching and Contract Decisions in<br />

Electricity Generation<br />

Michael Rice, Colorado School of Mines, 816 15th St., Golden, CO,<br />

80401, United States of America, mrice@mines.edu<br />

The shale gas boom and proposed plant emissions regulations could accelerate a<br />

switch from coal to gas in electricity generation portfolios. We analyze optimal<br />

fuel contracts for power plants facing price and regulatory uncertainty using<br />

stochastic programming.<br />

4 - Capacity Expansion under Uncertainty with Decison<br />

Dependent Probabilities<br />

Asgeir Tomasgard, Professor, Norwegian University of Science and<br />

Technology, Alfred getz vei 3, Trondheim, 7491, Norway,<br />

asgeir.tomasgard@iot.ntnu.no, Lars Hellemo, Paul I. Barton<br />

We propose an investment problem modeled as a stochastic program with<br />

decision dependent probabilities. We assume there is an activity or technology<br />

available that will alter the probabilities of the discrete scenarios occuring. By<br />

investing in such technology or activity, it is possible to increase the probability of<br />

some scenarios, while reducing the probability of the remaining scenarios. We<br />

demonstrate the use of a specialized decomposition algorithm for this class of<br />

problems.<br />

■ SB54<br />

54- Regency Ballroom A- Hyatt<br />

Nicholson Student Paper Prize II<br />

Cluster: Nicholson Student Paper Prize<br />

Invited Session<br />

Chair: Ashish Goel, Stanford University, Stanford, CA,<br />

United States of America, ashishg@stanford.edu<br />

1 - American Optimal Decisions - Portfolio Safeguard (PSG):<br />

Advanced Nonlinear Mixed-Integer Optimization Package<br />

Yi-Hao Kao,Stanford University, Stanford CA, United States of<br />

America, edward@yhkao.com, Benjamin Van Roy<br />

We consider a problem involving estimation of a high-dimensional covariance<br />

matrix that is the sum of a diagonal matrix and a low-rank matrix, and making a<br />

decision based on the resulting estimate. Such problems arise, for example, in<br />

portfolio management, where a common approach employs principal component<br />

analysis (PCA) to estimate factors used in constructing the low-rank term of the<br />

covariance matrix. The decision problem is typically treated separately, with the<br />

estimated covariance matrix taken to be an input to an optimization problem. We<br />

propose directed PCA, an efficient algorithm that takes the decision objective into<br />

account when estimating the covariance matrix. Directed PCA effectively adjusts<br />

factors that would be produced by PCA so that they better guide the specific<br />

decision at hand. We demonstrate through computational studies that directed<br />

PCA yields significant benefit, and we prove theoretical results establishing that<br />

the degree of improvement over conventional PCA can be unbounded.<br />

2 - Optimal Queue-size Scaling in Switched Networks<br />

Yuan Zhong, Massachusetts Institute of Technology, 235 Albany<br />

Street, Cambridge, MA, 02139, United States of America,<br />

zhyu4118@mit.edu, Neil Walton, Devavrat Shah<br />

We consider a switched network model, an important instance of the stochastic<br />

processing network (SPN) model (cf. Harrison [9]). The SPN model has been used<br />

successfully to model a broad spectrum of networked systems, including those<br />

arising in communications, manufacturing, transportation, inventory<br />

management, etc. The main operational issue in this model is ecient resource<br />

allocation under service constraints. We focus on online resource allocation<br />

policies, where the allocation decisions are made based on the current state<br />

and/or past history of the system. In the main result of this paper, we provide a<br />

new class of online policies that achieve optimal queue-size scaling for a class of<br />

switched networks, including input-queued switches. In particular, it establishes<br />

the validity of a long-standing conjecture (documented in [20]) about optimal<br />

queue-size scaling for input-queued switches.<br />

3 - Heavy Traffic Approximation of Equilibria in Resource<br />

Sharing Games<br />

Yu Wu, Stanford University, Stanford, CA, United States of<br />

America, yuwu@stanford.edu, Ramesh Johari, Luc Bui<br />

We consider a model of priced resource sharing that combines both queueing<br />

behavior and strategic behavior. We study a priority service model where a single<br />

server allocates its capacity to agents in proportion to their payment to the<br />

system, and users from different classes act to minimize the sum of their cost for<br />

processing delay and payment. As the exact processing time of this system is hard<br />

to compute and cannot be characterized in closed form, we introduce the notion<br />

of heavy traffic equilibrium as an approximation of the Nash equilibrium, derived<br />

by considering the asymptotic regime where the system load approaches capacity.<br />

We discuss efficiency and revenue, and in particular provide a bound for the price<br />

of anarchy of the heavy traffic equilibrium.<br />

INFORMS Phoenix – 2012<br />

98<br />

■ SB55<br />

55- Regency Ballroom B - Hyatt<br />

Revenue Management and Related Applications in<br />

Emerging Economies<br />

Cluster: Operations Research in Emerging Economies<br />

Invited Session<br />

Chair: Goutam Dutta, Professor, Indian Institute of Management,<br />

Production Quantitive Methods Area, Ahmedabad, Gujarat, Gu,<br />

380015, India, goutam@iimahd.ernet.in<br />

1 - Designing Pricing Policies for Cloud Service Providers<br />

Megha Sharma, Assistant Professor, Indian Institute of<br />

Management Calcutta, Diamond Harbour Road, Joka, Kolkata,<br />

WB, 700104, India, megha@iimcal.ac.in, Sumanta Basu,<br />

Soumyakanti Chakraborty<br />

Infrastructure-as-a-Service (Iaas) is expected to grow at a rapid pace in the next<br />

few years because of the flexibility offered to online platform providers in terms<br />

of meeting demand fluctuations. Pricing this service naturally becomes a critical<br />

issue for IaaS providers. We explore different pricing options for IaaS providers<br />

and their acceptance conditions for online businesses. We conclude by comparing<br />

our findings from different pricing plans and offer some guidelines on pricing<br />

IaaS.<br />

2 - Revenue Management and Pricing for Freight Transport<br />

in Indian Railways<br />

G Raghuram, Professor, Indian Institute of Management<br />

Ahmedabad, Wing 15, IIMA Campus, IIMA Campus, Ahmedabad,<br />

380015, India, graghu@iimahd.ernet.in<br />

The pricing policy for freight transport in Indian Railways demonstrates a<br />

recognition of where it is monopolistically placed, and competing with other<br />

modes. This policy is a departure from the earlier one which considered the<br />

impact of rail transport cost on the final price of the commodity. There are also a<br />

variety of discounts and surcharges depending on the traffic flows. This paper<br />

brings out the implication of the pricing policy, organizational processes behind<br />

the same and a way forward.<br />

3 - A Mathematical Programming Approach with Revenue<br />

Management for Home Loan Pricing<br />

Goutam Dutta, Professor, Indian Institute of Management,<br />

Production Quantitive Methods Area, Ahmedabad, Gujarat, Gu,<br />

380015, India, goutam@iimahd.ernet.in, Deepika Thakur<br />

We formulate a dynamic pricing model for home loans for a bank. The model<br />

optimizes the net present value of money available to the bank subject to pricing<br />

limits, cash flows. It also considers the demand price (interest rate) relationship<br />

and default probability as a function of interest rate. We then assume that<br />

different versions of demand function. We consider when demand function is<br />

given by a straight line, an exponential function and by rectangular hyperbola.<br />

■ SB56<br />

56- Curtis A- Hyatt<br />

Technology Management<br />

Contributed Session<br />

Chair: Yuya Kajikawa, Associate Professor, Tokyo Institute of<br />

Technology, 3-3-6 Shibaura, Minato-ku, Tokyo, Japan,<br />

kajikawa@mot.titech.ac.jp<br />

1 - Characterizing Business Models using System Dynamics<br />

Kwanyoung Im, POSTECH, 326/4 Eng building, Hyoja dong,<br />

Pohang, Korea, Republic of, kwanyoung@postech.ac.kr,<br />

Jaehun Lee, Inyoung Koh, Hyunbo Cho<br />

To apply the concept of a business model in real business practices, the<br />

consolidation of domain knowledge and application tools is needed. This research<br />

is aimed at reviewing the related literature and at proposing a business model<br />

application tool based on system dynamics.<br />

2 - The Influence of Knowledge Based on Technology<br />

Collaboration<br />

Yan Liu, Xi’an Jiaotong University, Postbox 2230, Xi’an, China,<br />

liuyan0220@stu.xjtu.edu.cn, Hong Cai<br />

We explore how a firm’s knowledge base structure influences the formation of its<br />

technological collaborating relationship. We use patent data from Chinese<br />

electrical & electronic industry from 2001 to 2008 to study the effect of firms’<br />

knowledge base on its propensity to establish technical cooperative relations.<br />

Counting data regression models show a strong link between these four<br />

properties of firm’s knowledge base and the propensity to form technological<br />

cooperating relationship.


3 - Participatory Challenge Platforms: Effective Integration of<br />

Public Expertise in Organization Efforts<br />

Tanya Kelley, Arizona State University, 411 North Central Ave.,<br />

Suite 400, Phoenix, AZ, 85004, United States of America,<br />

tanya.musgrave@asu.edu, Erik Johnston, Chase Gordon<br />

Participatory challenge platforms facilitate the integration of external individuals’<br />

personal interests and expertise into operational efforts of public and private<br />

organizations. We present results of NSF funded research on two such challenge<br />

platforms with distinct design considerations, 10,000 Solutions and The Policy<br />

Challenge. We focus on design tensions, outcomes, and how solutions are utilized<br />

by organizations. Findings suggest recommendations for future platform design<br />

and use.<br />

4 - Multilayer Analysis of Computational Intelligence for<br />

R&D Project Design<br />

Yuya Kajikawa, Associate Professor, Tokyo Institute of Technology,<br />

3-3-6 Shibaura, Minato-ku, Tokyo, Japan,<br />

kajikawa@mot.titech.ac.jp<br />

In this research, a methodology to analyze multilayer information is developed.<br />

We proposed and evaluated relatedness measures to comprehend semantic<br />

relationships between science, technology and social issues. Bibliometrics has<br />

been be used in previous works to comprehend trends of science and technology,<br />

however, have rather limited capability to support design than observation. We<br />

demonstrate that our methodology can support design of new R&D projects.<br />

■ SB57<br />

57- Curtis B- Hyatt<br />

Topics in Queueing Models<br />

Contributed Session<br />

Chair: Jayakrishnan Nair, Caltech, 1200 E. California Blvd., Pasadena,<br />

CA, 91125, United States of America, ujk@caltech.edu<br />

1 - A Fluid Model for the Multi-class Network Queues with<br />

Time-varying Arrivals and Routing Paths<br />

Beixiang He, North Carolina State University, Raleigh, NC, 27695,<br />

United States of America, bhe@ncsu.edu, Yunan Liu<br />

We introduce and analyze a fluid queue network with multiple customer classes,<br />

non-Markovian patience and service distributions, time-varying arrival rates and<br />

staffing level, and deterministic routing paths. Unlike the traditional Markovian<br />

(or proportional) routing, customers are routed according to their own service<br />

paths inside the network in a deterministic fashion. We provide an efficient<br />

algorithm to compute all standard performance functions, such as the queue<br />

lengths and waiting times.<br />

2 - Modeling Cross Correlation with Markovian Arrival Processes<br />

Sunkyo Kim, Professor, Ajou University, San 5, Suwon, Korea,<br />

Republic of, sunkyo@ajou.ac.kr<br />

We consider a generalization of modeling cross correlation in decomposition<br />

approximation of queueing networks. The cross correlation between randomly<br />

split streams is accounted for in the second and third moments of the merged<br />

process which is approximated as a two-state Markovian arrival process.<br />

3 - Stabilizing Policies for Matching Portals<br />

Burak Buke, The University of Edinburgh, School of Mathematics,<br />

King’s Buildings, JCMB, Edinburgh, United Kingdom,<br />

B.Buke@ed.ac.uk, Miklos Rasonyi, Hanyi Chen<br />

The portals, which match the people who provide a specific service with the<br />

people who demand the service, are becoming increasingly popular. In this talk,<br />

we assume that customers and suppliers arrive at the portal according to<br />

independent Poisson processes. Each customer can match with a specific supplier<br />

with a given probability independent of other suppliers and customers. We show<br />

that such a system is unstable if uncontrolled and suggest control policies to<br />

ensure stability.<br />

4 - When Heavy-tailed and Light-tailed Traffic Compete: Response<br />

Time Tail versus throughput Optimality<br />

Jayakrishnan Nair, Caltech, 1200 E. California Blvd., Pasadena,<br />

CA, 91125, United States of America, ujk@caltech.edu, Krishna<br />

Jagannathan, Adam Wierman<br />

We study a setting in which a heavy-tailed flow and a light-tailed flow compete<br />

for service from a single server. In this setting, the classical max-weight policy,<br />

while throughput optimal, induces heavy-tailed delays for the light-tailed flow.<br />

We prove that by careful design of intra-queue and inter-queue scheduling<br />

policies, one can achieve throughput optimality and light-tailed delays for the<br />

light-tailed flow, without affecting the delay tail for the heavy-tailed flow.<br />

INFORMS Phoenix – 2012<br />

99<br />

■ SB58<br />

58- Phoenix East- Hyatt<br />

Network Science<br />

Sponsor: Applied Probability<br />

Sponsored Session<br />

Chair: David Goldberg, Professor, Georgia Institute of Technology,<br />

Atlanta, GA, United States of America, dgoldberg9@isye.gatech.edu<br />

1 - Distributed Storage for Intermittent Energy Sources: Control<br />

Design and Performance Limits<br />

Yashodhan Kanoria, PhD Candidate, Stanford University, 350<br />

Serra Mall, Stanford, CA, 94305, United States of America,<br />

ykanoria@stanford.edu, David Tse, Baosen Zhang,<br />

Andrea Montanari<br />

The power output of renewable energy sources like wind and solar varies with<br />

time and location. Two strategies have been proposed to manage this variability:<br />

1) energy storage systems to average over time; 2) distributed generation to<br />

average over location. We introduce a network model to study the optimal use of<br />

storage and transmission resources, and propose a control design methodology.<br />

For specific network topologies we show asymptotic optimality and analytically<br />

quantify performance.<br />

2 - Temporal Load Balancing for Distributed Backup Scheduling<br />

Peter van de Ven, Postdoc, IBM, Yorktown Heights, NY,<br />

United States of America, petermvandeven@gmail.com,<br />

Angela Schoergendorfer, Bo Zhang<br />

We consider users that generate traffic to be transferred to a centralized backup<br />

server across a data network. Users have time-varying connectivity due to<br />

working hours, and backup attempts are initiated locally, without knowledge of<br />

the status of other users or the network load. The backup schedule is<br />

characterized by hourly backup probabilities, and we discuss how to choose the<br />

backup probabilities so as to stabilize the system and minimize the network costs.<br />

3 - Neighborly Measures for Sampling Independent Sets<br />

David Goldberg, Professor, Georgia Institute of Technology,<br />

Atlanta, GA, United States of America,<br />

dgoldberg9@isye.gatech.edu<br />

We study a family of measures which generalizes the well-known hardcore model<br />

for sampling the independent sets (i.s.) of a graph. In our model, the probability<br />

assigned to a given i.s. depends not only on its cardinality, but also on how many<br />

excluded nodes are adjacent to exactly k nodes belonging to the i.s. for each k.<br />

We give tight conditions for correlation decay in the infinite regular tree under a<br />

log-convexity assumption, and gain further insight through a perturbative<br />

analysis.<br />

■ SB59<br />

SB59<br />

59- Phoenix West- Hyatt<br />

Models for Online Content and Advertising Markets<br />

Sponsor: Applied Probability<br />

Sponsored Session<br />

Chair: Assaf Zeevi, Columbia Business School, New York, NY,<br />

United States of America, assaf@gsb.columbia.edu<br />

1 - Buy-it-now or Take-a-chance: A Mechanism for Real-time<br />

Price Discrimination<br />

Hamid Nazerzadeh, Marshall School of Business, University of<br />

Southern California, Los Angeles, CA, United States of America,<br />

hamidnz@marshall.usc.edu, Elisa Celis, Greg Lewis,<br />

Markus Mobius<br />

Increasingly sophisticated consumer tracking technology allows advertisers to<br />

reach narrowly targeted consumer demographics. Such targeting improves the<br />

match quality between advertisers and users, but can also result in thin markets.<br />

Using historical bidding data from a large advertising exchange, we show that<br />

there is often a substantial gap between the highest and second highest<br />

willingness to pay. With this motivation, I present a simple sequential screening<br />

mechanism.<br />

2 - Learning Overlapping Community Structure in Social Networks:<br />

The Leader-follower Algorithm<br />

Tauhid Zaman, Massachusetts Institute of Technology, 77<br />

Massachusetts Ave., Cambridge, MA, United States of America,<br />

zlisto@mit.edu, Devavrat Shah<br />

We present the leader-follower algorithm (LFA) for learning overlapping<br />

community structure in social networks. It requires no input parameters and has<br />

a run-time linear in the network size. We prove that it has good performance on<br />

certain network structures which we show exist in real social data. We also find<br />

that the LFA can exactly recover the true overlapping community structure for<br />

many real social networks while more common methods fail.


SB60<br />

3 - Telling the “Hot” from the “Not”: Online Content<br />

Recommendations on the Internet<br />

Yonatan Gur, Columbia Business School, New York, NY,<br />

United States of America, ygur14@gsb.columbia.edu,<br />

Omar Besbes, Assaf Zeevi<br />

A new class of online services allows publishers to direct readers to other webbased<br />

content they may be interested in. We study this dynamic recommendation<br />

problem, focusing on challenges introduced by the massive stream of new content<br />

and the short shelf-life of articles, and focusing on topic-based popularity as basis<br />

for recommendations. Work is based on collaboration with a leading provider of<br />

online content recommendations.<br />

■ SB60<br />

60- Remington- Hyatt<br />

Predictability and Resource Allocation Decisions in<br />

Air Traffic Management<br />

Sponsor: Aviation Applications<br />

Sponsored Session<br />

Chair: Shervin Ahmad Beygi, Lead Operations Research Analyst,<br />

Metron Aviation Inc., 45300 Catalina Ct, Dulles, VA, 20166,<br />

United States of America, shervin.ahmadbeygi@metronaviation.com<br />

1 - Performance-based Ground Delay Program Decision-making<br />

using Multiple Criteria : Single Airport Case<br />

Yi Liu, University of California, Berkeley, 107 McLaughlin Hall,<br />

Berkeley, CA, 94720, United States of America,<br />

liuyi.feier@gmail.com, Mark Hansen<br />

We develop performance metrics for capacity, efficiency and predictability, and<br />

show how these metrics may be traded off in the design of Ground Delay Program<br />

(GDP) under capacity uncertainty. We link the performance to the decisions on<br />

GDP clearance time and the scope of the program. This capability allows the<br />

service provider to make performance-based GDP decisions using multiple<br />

criteria.<br />

2 - Airline Voting Mechanisms for Parameter Selection for Air<br />

Traffic Flow Management (ATFM) Initiatives<br />

Vikrant Vaze, Member Research Staff, Philips Research North<br />

America, 345 Scarborough Road, Briarcliff Manor, NY, 10510,<br />

United States of America, vikrant.vaze@philips.com,<br />

Cynthia Barnhart<br />

Parameter selection for ATM initiatives is performed by the regulators while<br />

taking airline preferences into account. We design a voting scheme which can<br />

replace current ad-hoc methods. Strategic behavior is modeled using an integer<br />

programming formulation which explicitly accounts for tie-breaking rules. We<br />

solve for a Nash equilibrium using best response heuristics. We evaluate<br />

equilibrium properties including existence, uniqueness, convergence, system<br />

optimality and pareto optimality.<br />

3 - Flight Cancellation Behavior and Delay Savings Estimates<br />

Michael Seelhorst, University of California Berkeley, 1710<br />

Delaware St., Berkeley, CA, 94703, United States of America,<br />

mseelhorst@berkeley.edu, Mark Hansen<br />

A discrete choice model was used to infer airline flight cancellation preferences<br />

from a sample of on-time performance flight data. The predicted cancellation<br />

probabilities were then used as inputs to delay savings estimates, which were<br />

approximated with a continuous technique. The results from this work will be<br />

useful for incorporating flight cancellation decisions into system-wide delay<br />

forecasting models.<br />

■ SB61<br />

61- Russell- Hyatt<br />

Airport/Airline Operations Management<br />

Sponsor: Aviation Applications<br />

Sponsored Session<br />

Chair: Ahmed Ghoniem, Assistant Professor, University of<br />

Massachusetts Amherst, 121 Presidents Dr., Amherst, MA, 01003,<br />

United States of America, aghoniem@isenberg.umass.edu<br />

1 - Enhanced Column Generation for Multiple-runway Aircraft<br />

Sequencing Problem<br />

Farbod Farhadi, Doctoral Student, University of Massachusetts<br />

Amherst, Isenberg School of Management, 121 Presidents Drive,<br />

Amherst, MA, 01003, United States of America,<br />

ffarhadi@som.umass.edu, Ahmed Ghoniem<br />

We address mixed mode multiple-runway aircraft sequencing problem. An MIP<br />

formulation is enhanced with valid inequalities and symmetry-defeating<br />

INFORMS Phoenix – 2012<br />

100<br />

constraints. An alternative set partitioning problem is solved by column<br />

generation using multiple algorithmic features that accelerate the convergence<br />

and tighten the duality gap.<br />

2 - Aircraft Rescheduling under Operation Disruptions<br />

Mohamed Kharbeche, Postdoctoral Associate, Qatar University,<br />

Mechanical and Industrial Engineering, Doha, 2713, Qatar,<br />

mkharbec@qu.edu.qa, Ameer Al-Salem, Ahmed Ghoniem,<br />

Hanif D. Sherali<br />

We address optimization models for multiple-runway aircraft sequencing<br />

problems under operation disruptions, namely, aircraft delays, new aircraft<br />

arrivals and flight cancellations. Extensive computational results are reported for<br />

exact as well as heuristic methods.<br />

3 - An Integrated Approach for Airline Flight Scheduling, Fleet<br />

Assignment, and Aircraft Routing<br />

Ki-Hwan Bae, Virginia Polytechnic and State University, 250<br />

Durham Hall, Blacksburg, VA, 24061, United States of America,<br />

kbae04@vt.edu, Hanif D. Sherali, Mohamed Haouari<br />

We propose a model that integrates certain aspects of the schedule design, fleet<br />

assignment, and aircraft routing processes, while considering various modeling<br />

features. Maintenance routing decisions as well as through-flight opportunities<br />

are additionally incorporated in our model, and we apply a series of different<br />

solution techniques to handle the large-scale model formulation, reduce its<br />

complexity, and enhance its solvability.<br />

4 - Environmental Value of Optimal Separation in Continuous<br />

Descent Arrivals<br />

Heng Chen, Isenberg School of Management, 121 Presidents<br />

Drive, University of Massachusetts, Amherst, MA, 01003,<br />

United States of America, heng@som.umass.edu, Senay Solak<br />

Optimal separation in continuous descent arrivals (CDA) refers to the use of<br />

spacing policies that are shown to be optimal based on stochastic dynamic models.<br />

These models involve optimization of different objective structures defined as<br />

functions of runway utilization and airline operating costs. Considering some<br />

potentially implementable objective structures, we derive both analytical and<br />

numerical results that quantify the environmental value of using optimal<br />

separation policies in CDA.<br />

■ SB62<br />

62- Borein A - Hyatt<br />

Joint Session Auctions/MSOM:<br />

Auctions and Procurement<br />

Sponsor: Auctions & Manufacturing & Service Oper Mgmt<br />

Invited Session<br />

Chair: Gabriel Weintraub, Columbia Business School,<br />

3022 Broadway, New York, NY, 10027, United States of America,<br />

gyw2105@columbia.edu<br />

Co-Chair: Sang Won Kim, Columbia Business School,<br />

3022 Broadway, New York, NY, 10027, United States of America,<br />

skim14@gsb.columbia.edu<br />

1 - Production Cost Forecasts and Procurement Efficiency in<br />

Supply Chains<br />

Tunay Tunca, Associate Professor, University of Maryland,<br />

Robert H. Smith School of Business, College Park, MD, 20742,<br />

United States of America, ttunca@rhsmith.umd.edu<br />

We study the role supplier cost forecasting under upstream competition in supply<br />

chain procurement and examine the implications on market and channel<br />

performance. We derive a channel competitiveness measure that combines the<br />

forecast information structure in the supply chain with upstream channel<br />

fragmentation and study its relationship with supply chain efficiency. We show<br />

that such a measure can be a better indicator of supply chain performance<br />

compared to traditional measures.<br />

2 - Analysis of the Vickrey-Clarke-Groves (VCG) Mechanism in<br />

Combinatorial Auctions<br />

Sang Won Kim, Columbia Business School, 3022 Broadway,<br />

New York, NY, 10027, United States of America,<br />

skim14@gsb.columbia.edu, Jay Sethuraman, Gabriel Weintraub<br />

Recent theoretical works show that the VCG mechanism can have undesirable<br />

properties, such as low revenues, in combinatorial auction settings. In contrast,<br />

recent empirical work shows the opposite for a specific important application. In<br />

this work, we develop new theoretical results for VCG mechanism that explain<br />

this apparent paradox. More broadly, we show when VCG is expected to perform<br />

well in applications and when it does not.


3 - Bundled Procurement for (Free) Technology Acquisition and<br />

Future Competition<br />

Leon Chu, University of Southern California, Los Angeles, CA,<br />

United States of America, leonyzhu@usc.edu, Yunzeng Wang<br />

We study the effectiveness of a procurement mechanism of a buyer that bundles<br />

the product procurement with the technology acquisition. It turns out that each<br />

supplier has a dominant offering strategy for the technology provision that only<br />

depends on the technology difference of the suppliers and the ratio between the<br />

current project size and the future market size. We find that a ratio of 10% is<br />

sufficient for the suppliers to offer the best technologies for most reasonable<br />

market conditions.<br />

4 - Procurement Auctions with Error-prone RFQs<br />

Yan Yin, University of Michigan, Ann Arbor, MI,<br />

United States of America, yinyan@umich.edu<br />

Many requests for quotes (RFQs) contain errors that will trigger re-design (and<br />

windfall supplier profits) after production has begun. We study how the buyer’s<br />

payment changes in the error rate, supplier’s design knowledge, and competition<br />

intensity. Surprisingly, we find that a higher error rate can sometimes decrease<br />

the buyer’s total payment by mitigating supplier windfall profits. We also show<br />

“pre-paying” re-design costs can be an alternative strategy to stem windfall<br />

profits.<br />

■ SB63<br />

63- Borein B- Hyatt<br />

Worker and Consumer Behaviors<br />

Contributed Session<br />

Chair: Corey Kiassat, PhD Candidate, University of Toronto, Faculty of<br />

Applied Science & Engineering, 5 King’s College Road, Toronto, M5S<br />

3G8, Canada, ckiassat@mie.utoronto.ca<br />

1 - Hiring An Envy-free Secretary is Costly<br />

Nguyen Truong, IEOR PhD Student, University of California-<br />

Berkeley, 2414 Dwight Way #6, Berkeley, CA, 94704,<br />

United States of America, nltruong@berkeley.edu<br />

We consider the minimum expected rank secretary problem, where it is well<br />

known that the optimal stopping mechanism selects an applicant with rank<br />

$\approx 3.8695$. This mechanism, however, may not deliver intended results:<br />

early (late) applicants wish to delay (move to earlier) their interviews. In order<br />

for each applicant to not envy any other’s position, the optimal expected rank of<br />

the hired applicant is shown to be $\Omega(\ln(n))$. As such, it is costly to have<br />

envy-free participants.<br />

2 - Consumer Behavior Analysis in a Convenient Store Based on<br />

Shopping Path Data<br />

Chenqu Luo, Master Student, Department of Industrial<br />

Engineering, Tsinghua University, Building Shunde Room South<br />

607, Beijing, 100084, China, luocq11@mails.tsinghua.edu.cn,<br />

Lefei Li<br />

The consumers’ shopping path indicates much to their shopping behaviors. We<br />

develop a utility function that describes consumers’ preference on the next<br />

movement and use Beyesian method for estimation. Statistics show the shopping<br />

behavior in a convenient store is quite different from that in a supermarket.<br />

Moreover, we can identify typical path patterns that are closely related to the<br />

consumers’ target products and visiting time, which potentially support the<br />

managers’ category decisions.<br />

3 - Enhancing System Performance through Failure Risk Analysis<br />

from a Worker Characteristic Perspective<br />

Corey Kiassat, PhD Candidate, University of Toronto, Faculty of<br />

Applied Science & Engineering, 5 King’s College Road, Toronto,<br />

M5S 3G8, Canada, ckiassat@mie.utoronto.ca, Dragan Banjevic<br />

We want to perform a failure risk analysis to enhance system performance. We<br />

are specifically interested in the effect of worker characteristics on failure risk. In<br />

the case of failures caused by workers, the Decision Maker (DM) must intervene<br />

to mitigate the risk. We develop a revenue model, using the proportional hazards<br />

model, to provide the DM with a cost-benefit analysis, balancing the advantage of<br />

risk reduction against the direct cost of the intervention method.<br />

4 - Intrapersonal Heterogeneity in Intertemporal Choice<br />

Behavior: Evidence<br />

Sasha Bartashnik, Memorial Sloan-Kettering Cancer Center,<br />

405 Lexington Avenue, 3rd Floor, New York, NY, 10174,<br />

United States of America, bartasha@mskcc.org, Paul Kattuman<br />

We examine whether the traditional binary classification of individuals into<br />

dynamically consistent exponential or present-biased quasi-hyperbolic<br />

discounters is absolute using De Nederlandsche Bank Household Survey data.<br />

Most individuals are internally heterogeneous. Intrapersonal heterogeneity is<br />

significant and fairly stable over time. Our results have significant implications for<br />

enhancing individual and societal welfare via individualized choice architectures,<br />

particularly in healthcare.<br />

INFORMS Phoenix – 2012<br />

101<br />

■ SB66<br />

SB66<br />

66- Ellis West- Hyatt<br />

Joint Session DM/QSR: Sensor-based<br />

Health Informatics<br />

Sponsor: Data Mining & Quality, Statistics and Reliability<br />

Sponsored Session<br />

Chair: Hui Yang, Assistant Professor, University of South Florida,<br />

Tampa, FL, 33620, United States of America, huiyang@usf.edu<br />

1 - Spatiotemporal Change Detection Methods in Nonhomogeneous<br />

Change Size<br />

Sung Won Han, Fellow, Hoffmann-La Roche Inc.,<br />

340 Kingsland St., Nutley, NJ, United States of America,<br />

sung_won.han@roche.com, Seoung Bum Kim, Kyu Jong Lee,<br />

Hua Zhong<br />

In the classical change point detection problem, the change pattern is<br />

homogeneous over time and space, and the change size is sustained after the<br />

change. However, in practical spatotemporal health care surveillance, the<br />

underlying assumptions of problems are more complicated. Change size can be<br />

various over space, so the change size can be large at the center of outbreak but<br />

small at the edge. We investigate the existing methods to see how they perform<br />

under the complex cases.<br />

2 - Localization of Myocardial Infarction using Vectorcardiogram<br />

Octant Transition Network<br />

Trung Le, Oklahoma State University, 322 Engineering North,<br />

Stillwater, Ok, 74075, United States of America,<br />

trung.le@okstate.edu, Satish Bukkapatnam<br />

Myocardial Infarction is a leading cause of death in the US. Detecting the location<br />

of MI in the early stages can significantly improve treatment efficiency and reduce<br />

mortality risks. We present an approach that uses the topological features of<br />

octant network reconstructed from VCG signals to detect and localize MI.<br />

Extensive tests using data of from Physionet indicate that transition features can<br />

differentiate healthy, inferior, anterior MI with >92% sensitivity and >93%<br />

specificity.<br />

3 - Multiscale Adaptive Basis Function Modeling of<br />

Spatiotemporal Signals<br />

Hui Yang, Assistant Professor, University of South Florida,<br />

Tampa, FL, 33620, United States of America, huiyang@usf.edu<br />

Mathematical models facilitate the characterization and recognition of underlying<br />

biological patterns. However, there are practical issues pertinent to model efficacy,<br />

robustness, and generality. This paper presents a multiscale adaptive basis<br />

function approach to model space-time cardiac pathological behaviors, using the<br />

“best matching” projections of characteristic waves onto a dictionary of nonlinear<br />

basis functions. The model performance is experimentally evaluated with realworld<br />

signals.<br />

4 - Developing a Healthcare Cost Index using Advanced Analytics<br />

Dursun Delen, Professor, Oklahoma State University, 700 N.<br />

Greenwood Ave., Tulsa, OK, 74106, United States of America,<br />

dursun.delen@okstate.edu, James Hess<br />

Due to high variability, cost of healthcare has become one of the largest risk<br />

factors for today’s businesses. Establishment of a practical healthcare commodity<br />

index provides the pathway to transparency, which allows businesses to trade<br />

healthcare cost futures, and ultimately creates the open market environment<br />

necessary to encourage and support competitive pricing. This presentation focuses<br />

on the overall process of developing (based on data and analytics) such a<br />

healthcare cost index.


SB67<br />

■ SB67<br />

67- Ellis East- Hyatt<br />

System Reliability and Maintenance<br />

Sponsor: Quality, Statistics and Reliability<br />

Sponsored Session<br />

Chair: Nan Chen, Assistant Professor, National University of Singapore,<br />

Department of Industrial and Systems Eng, 1 Engineering Drive 2,<br />

Singapore, 129789, Singapore, isecn@nus.edu.sg<br />

1 - Criticality Index for Degrading Components under<br />

Dynamic Environments<br />

Xiao Liu, liuxiaodnn_1@hotmail.com, Khalifa N. Al-Khalif,<br />

Dingguo Hua, Abdel Magid Hamouda, David Coit, Elsayed Elsayed<br />

Criticality index of a component depends on its degradation path and system<br />

configuration. This presentation investigates the criticality analysis for degrading<br />

components under dynamic environmental conditions. The component<br />

degradation is modeled by a k-dimensional Wiener process, and component fails<br />

when any of these k degradation paths attains its own threshold level. In the<br />

numerical examples, we illustrate the computation of component criticality in<br />

different system configurations.<br />

2 - A Quantile Regression Approach to Analyze Accelerated Life<br />

Testing Data<br />

Nan Chen, Assistant Professor, National University of Singapore,<br />

Department of Industrial and Systems Eng, 1 Engineering Drive 2,<br />

Singapore, 129789, Singapore, isecn@nus.edu.sg<br />

We propose a quantile regression framework to model the accelerated life tests<br />

(ALT) data. The quantile of the failure distribution at usage level can be easily<br />

estimated. Compared with traditional parametric regression methods, quantile<br />

regression is distribution free, efficient in presence of censoring, and is more<br />

flexible in modeling ALT relations. In addition, the method can be used naturally<br />

in the cases when the failure-free life depends on the accelerating factor.<br />

3 - An Integrated Approach to the Design of Statistically Precise<br />

and Energy Efficient Accelerated Tests<br />

Haitao Liao, Associate Professor, University of Arizona, Tucson, AZ,<br />

85721, United States of America, hliao@email.arizona.edu,<br />

Dan Zhang<br />

In this paper, an integrated experimental design approach is introduced with the<br />

objective of maximizing the reliability estimation precision while minizing the<br />

energy consumption of an accelerated test. Relevant statistical inference methods<br />

and required experimental needs and technologies are discussed.<br />

4 - Reliability and Maintenance for Dependent Competing Failure<br />

Processes with Shifting Thresholds<br />

Qianmei Feng, Associate Professor, Houston University, E206<br />

Engineering Bldg 2, Houston University, Houston, TX, 77204-<br />

4008, United States of America, qmfeng@uh.edu, Lei Jiang,<br />

David Coit<br />

We present reliability and maintenance models for systems subject to multiple<br />

dependent competing failure processes with a changing and dependent failure<br />

threshold. Three cases of dependency between shock process and hard failure<br />

threshold level are studied. Reliability models are developed based on degradation<br />

and random shock modeling. Two preventive maintenance policies are also<br />

applied and compared. Then an MEMS example is given to demonstrate the<br />

reliability models and maintenance polices.<br />

■ SB68<br />

68- Suite 312- Hyatt<br />

Finance: Risk Management<br />

Contributed Session<br />

Chair: Woojin Chang, Seoul National University, Gwanak-gu<br />

Gwanak-ro 1, Seoul, Korea, Republic of, changw@snu.ac.kr<br />

1 - Continuous Dynamic Portfolio Choice with Bayesian Regret<br />

Shea Chen, University of California, Berkeley, 301 Main St.,<br />

Unit 34E, San Francisco, CA, 94105, United States of America,<br />

sheachen@berkeley.edu, Andrew Lim<br />

We formulate a continuous-time portfolio choice problem in which the investor is<br />

uncertain about parameters of the model, and the objective function is a Bayesian<br />

version of relative regret. The optimal portfolio is characterized and shown to<br />

involve a “tilted” posterior, where the tilting is defined in terms of a family of<br />

stochastic benchmarks.<br />

INFORMS Phoenix – 2012<br />

102<br />

2 - Forecasting the Stress of Credit Card Portfolios<br />

Mee-chi So, University of Southampton, Southampton<br />

Management School, Southampton, SO17 1BJ, United Kingdom,<br />

m.so@soton.ac.uk<br />

This study aims to develop models to forecast the default rate of credit card<br />

accounts under different economic scenarios. Two modelling approaches were<br />

extended to include the impact of lenders’s actions within the model. The first<br />

approach was a regression model of the aggregate losses based on economic<br />

variables. The second approach was a set of vintage level models which<br />

highlighted the months on books effect on credit losses. A case study using the<br />

models was described.<br />

3 - Credit Rating Migration Model: Markov Switching Process<br />

Woojin Chang, Seoul National University, Gwanak-gu Gwanak-ro<br />

1, Seoul, Korea, Republic of, changw@snu.ac.kr, Sung Yeol Oh<br />

We develop a credit rating migration model based on a discrete-time discretevalued<br />

Markov process depending on hidden Markov chain. We also present a<br />

parameter estimation procedure for the proposed model using the EM algorithm.<br />

The likelihood ratio test shows that our model depending on hidden Markov<br />

chain better describes the credit rating dynamics than a benchmark Markov chain<br />

model.<br />

4 - A Model for Dynamic TaxCredit Utilization<br />

Nilofar Varzgani, PhD Student, Rutgers University, Rutgers<br />

Business School, Newark, NJ, 07102, United States of America,<br />

nilofarv@pegasus.rutgers.edu, Suresh Govindaraj,<br />

Michael Katehakis<br />

We develop a new stochastic dynamic programming model for dynamic tax credit<br />

utilization for a firm that provides maximum expected benefit over a rolling<br />

horizon. The model takes into account earnings and profits, net operating losses,<br />

and credit carryovers. We present computation to demonstrate the benefit the<br />

model provides.<br />

■ SB69<br />

69- Suite 314- Hyatt<br />

Data Driven Portfolio Optimization<br />

Cluster: Optimization in Finance<br />

Invited Session<br />

Chair: Victor DeMiguel, Professor, London Business School, Regent’s<br />

Park, London, NW1 4SA, United Kingdom, avmiguel@london.edu<br />

1 - Computing General Arbitrage Bounds for European Basket<br />

Options via Dantzig-Wolfe Decomposition<br />

Luis Zuluaga, Assistant Professor, Lehigh University,<br />

200 West Packer Ave., Bethlehem, United States of America,<br />

luis.zuluaga@lehigh.edu<br />

We study the problem of computing bounds on the price of a basket option given<br />

the only assumption of absence of arbitrage, and information about prices of<br />

other basket options. We provide a simple way to compute this type of bounds via<br />

a suitable Dantzig-Wolfe decomposition. We illustrate our results by computing<br />

upper and lower arbitrage bounds on gasoline/heating oil crack spread options,<br />

and Alternative Risk Transfer (ART) products.<br />

2 - Performance-based Regularization in Mean-CVaR Portfolio<br />

Optimization<br />

Gah-Yi Vahn, Assistant Professor, London Business School,<br />

Regent’s Park, London, United Kingdom, gvahn@london.edu,<br />

Noureddine El Karoui, Andrew Lim<br />

We introduce performance-based regularization (PBR), a new approach to<br />

addressing estimation risk in data-driven optimization, to mean-CVaR portfolio<br />

optimization. We assume the available log-return data is iid, and detail the<br />

approach for two cases: nonparametric and parametric (the log-return<br />

distribution belongs in the elliptical family). We show that the PBR methods<br />

produce efficient frontiers that are, on average, closer to the population efficient<br />

frontier with less variability.<br />

3 - Size Matters: Optimal Calibration of Shrinkage Estimators for<br />

Portfolio Selection<br />

Alberto Martin-Utrera, Mr, University Carlos III of Madrid,<br />

C/ Madrid, 126-28903, GETAFE, Sp, 28903, amutrera@estecon.uc3m.es<br />

We carry out a comprehensive investigation of shrinkage estimators in the<br />

context of portfolio optimization and we make several contributions to this field.<br />

First, we propose new shrinkage estimators for both the moments of asset returns<br />

and portfolio weights. Second, we propose novel calibration criteria to compute<br />

the optimal shrinkage intensity. Finally, we propose a parametric and a<br />

nonparametric approach to estimate the shrinkage intensity.


■ SB70<br />

70- Suite 316- Hyatt<br />

Economics of Information Systems<br />

Sponsor: Information Systems<br />

Sponsored Session<br />

Chair: Wael Jabr, Assistant Professor, University of Calgary, 2500<br />

University Dr NW, Calgary, AB, T3A6L5, Canada, wjabr@ucalgary.ca<br />

1 - Are Online Seller Recommendations Biased? An Empirical<br />

Investigation of OTA Hotel Listings<br />

Ori Marom, RSM Erasmus University, Burgemeester Oudlaan 50,<br />

Rotterdam, 3062 PA, Netherlands, omarom@rsm.nl, Roman Peskin<br />

Online travel agents such as Expedia and Priceline.com often have tremendous<br />

power to direct online buyers to a small subset of available products. Our paper<br />

investigates whether OTA selections of top-listed hotels can be regarded as biased<br />

from buyers’ viewpoint. Our empirical investigation indicates that that while OTA<br />

websites provide buyers with valuable search assistance by locating good-valued<br />

deals they also influence them to purchase relatively expensive products.<br />

2 - Social Media and Firm Equity Value<br />

Jie Zhang, University of Texas Arlington, 701 S West St.,<br />

Arlington, TX, 76019, United States of America, jiezhang@uta.edu,<br />

Xueming Luo<br />

Companies have advocated social media to engage consumers and gauge product<br />

market performance. We empirically examine whether social media metrics are<br />

related to firm equity value. The results from the developed time-series models<br />

suggest that social media-based metrics (blogs and reviews) have higher predictive<br />

value for firm stock market performance compared to web traffic and search. We<br />

also find that firm stock performance responds faster to the social media-based<br />

metrics.<br />

3 - Learning under Ambiguity: An Experiment<br />

Yaroslav Rosokha, PhD Student, The University of Texas at Austin,<br />

2225 Speedway Stop C3100, Austin, TX, 78712-1690, United<br />

States of America, yaroslav.rosokha@gmail.com, Othon Moreno<br />

Gonzalez<br />

We design and conduct an economic experiment to compare the learning process<br />

of the agents under risk and ambiguity. Decisions are made in conjunction with a<br />

sequence of draws (with replacement), allowing us to track beliefs over time. We<br />

estimate: (1) Bayesian updating allowing for base rate fallacy; (2) Bayesian<br />

updating with multiple priors; and (3) Reinforcement Learning. Our findings<br />

suggest that new signal in is over-weighted more in risky than in ambiguous<br />

environments.<br />

4 - The Role of Online Reviews in Mitigating Product Uncertainties<br />

Wael Jabr, Assistant Professor, University of Calgary, 2500<br />

University Dr NW, Calgary, AB, T3A6L5, Canada,<br />

wjabr@ucalgary.ca, Mohammad Rahman<br />

User reviews are widely recognized as an important resource that customers rely<br />

on to help guide their purchases. This paper evaluates the efficiency of the market<br />

for information at reducing the uncertainty of consumers. We use Bayesian Belief<br />

and Information Gain to quantify such efficiency. We then show that the market<br />

design for information release plays a major role in affecting this efficiency. We<br />

investigate the evolution of reviews and corresponding efficiencies and market<br />

design issues.<br />

■ SB71<br />

71- Suite 318- Hyatt<br />

Digital and Social Networks I<br />

Sponsor: eBusiness<br />

Sponsored Session<br />

Chair: Jui Ramaprasad, Assistant Professor, McGill University,<br />

1001 Sherbrooke West, Montreal, QC, H3H2V1, Canada,<br />

jui.ramaprasad@mcgill.ca<br />

1 - Celebrity Effect? An Empirical Study of Social Influence and<br />

Online Product Review Behavior<br />

Mingfeng Lin, University of Arizona, 1130 E. Helen St., Tucson,<br />

AZ, 85721, United States of America, mingfeng@eller.arizona.edu,<br />

Paulo Goes<br />

We study the effect of consumers’ online interactions on their product review<br />

behaviors. A popular form of users’ online interaction is the “subscription” model<br />

that gives priority to contents generated by the person subscribed to. Using a<br />

panel dataset from epinions.com, we examine how users’ product review<br />

behaviors evolve as their online followership – peers who are silent – grows. Our<br />

results have implications for research on word-of-mouth and user-generated<br />

content (UGC) sites in general.<br />

INFORMS Phoenix – 2012<br />

103<br />

2 - Are Paid Subscriptions on Music Social Networks Contagious?<br />

Ravi Bapna, Professor, University of Minnesota, 321 19th Avenue<br />

South, 55410, Minneapolis, MN, 55455, United States of America,<br />

rbapna@umn.edu, Akhmed Umyarov<br />

In this paper, we present a novel randomized experiment that tests the existence<br />

of causal peer influence in the general population of a particular large-scale<br />

online social network. Both simple t-test and logistic regression indicate that<br />

user’s adoption of a product causes her online friends to pay for it and adopt it as<br />

well.<br />

3 - Exploring the Role of Cultural Differences in Crowd-funder<br />

Contribution Decisions<br />

Gordon Burtch, Temple University, 1810 N 13th Street, Speakman<br />

Hall 201F, Philadelphia, PA, 19122, United States of America,<br />

gburtch@temple.edu, Anindya Ghose, Sunil Wattal<br />

Contrary to Thomas Friedman’s Flat World hypothesis, here, we argue that the<br />

world is by no means flat, as distance continues to exist along dimensions other<br />

than the physical. Many online marketplaces today offer participants the<br />

opportunity to engage in economic exchange with others the world over. As a<br />

result, the differences between parties are often striking. Bearing this in mind, we<br />

explore the impact of cultural differences on lending on the world’s largest microfinance<br />

website, Kiva.org. Leveraging an aggregate dataset of country-to-country<br />

lending, incorporating three million lending actions over a five-year period, we<br />

find that cultural differences are negatively associated with lending and,<br />

interestingly, that this association is decreasing in physical distance (we interpret<br />

this as an awareness effect). We consider the implications of this finding for the<br />

purveyors of globalized online marketplaces, making recommendations regarding<br />

information presentation and the application of institutional trust mechanisms.<br />

■ SB72<br />

SB72<br />

72- Suite 322- Hyatt<br />

OR Applications in Cloud Computing<br />

Cluster: Cloud Computing<br />

Invited Session<br />

Chair: Emrah Zarifoglu, Optimization Scientist, IBM,<br />

1 Franklin Parkway, Building 910, San Mateo, CA, 94402,<br />

United States of America, emrah.zarifoglu@utexas.edu<br />

1 - Pricing Differentiated Services in Cloud Computing Market<br />

Linna Du, PhD Student, University of Connecticut, School of<br />

Business, 2100 Hillside Road Unit 1041, Storrs, CT, 06269,<br />

United States of America, linna.du@business.uconn.edu<br />

The cloud computing market is featured as a large scale market for a non-storable<br />

commodity with instantaneously released capacity, differentiated services,<br />

stochastic demands and risk-averse vendor. We employ queueing network<br />

analysis to capture the system unique features and long run behavior. Our model<br />

helps business managers develop actionable pricing strategies for increasing the<br />

revenue rate, controlling the user’s service adoption and hedging against<br />

variability in realized services.<br />

2 - Stochastic Scheduling for Cloud Computing<br />

Laurent Pauwels, The University of Sydney, Rm 481,<br />

Merewether Building, Sydney, Australia,<br />

laurent.pauwels@sydney.edu.au, Dmytro Matsypura<br />

We consider a scheduling problem of a software-as-a-service provider (cloud<br />

user). The provider has access to virtually unlimited computing resources on a<br />

pay-as-you-go basis. The jobs that need to be scheduled have uncertain sizes and<br />

completion times. We present stochastic program formulations with respect to<br />

various measures of optimality, investigate structural properties of optimal<br />

solutions and analyze worst-case performance of various heuristics.<br />

3 - An Analytical Approach to Solving Load Balancing Problem in<br />

Cloud Computing<br />

Emrah Zarifoglu, Optimization Scientist, IBM, 1 Franklin Parkway,<br />

Building 910, San Mateo, CA, 94402, United States of America,<br />

emrah.zarifoglu@utexas.edu, Ilyas Iyoob<br />

The dynamic cost structure increases the importance of intelligent provisioning<br />

and management in cloud computing. We develop an optimization model to<br />

decide high-mark utilization and low-mark utilization values to turn on and off<br />

VMs while minimizing provisioning and maintenance costs. Solving the same<br />

optimization problem at different points in time provides us with a dynamic VM<br />

load balancing policy. The robustness of the policy relies on the agility of<br />

periodical model corrections.


SB73<br />

■ SB73<br />

73- Suite 324- Hyatt<br />

Market Microstructure and High-Frequency Trading<br />

Cluster: Quantitative Finance<br />

Invited Session<br />

Chair: Gerry Tsoukalas, University of Pennsylvania,<br />

The Wharton School, Philadelphia, PA, United States of America,<br />

gtsouk@wharton.upenn.edu<br />

1 - General State Space Models in Electronic Market Making<br />

Vibhav Bukkapatanam, PhD Candidate, Stanford University,<br />

141O Huang Engineering Center, Stanford, CA, 94305,<br />

United States of America, vibhav@stanford.edu<br />

In recent years, the dramatic growth in electronic trading has revolutionized<br />

financial markets and led to the proliferation of high frequency market makers. In<br />

this work, we analyze how general state space models can be used in several key<br />

components of a maket making system, including spot variance and correlation<br />

estimation, regime switching modeling of high frequency data and optimal<br />

inventory control based bid-ask spreads estimation.<br />

2 - Predicting the Impact of a Proposed Securities<br />

Exchange Regulation<br />

Waraporn Tongprasit, Stanford University, Stanford, CA, United<br />

States of America, Waraporn@stanford.edu, Benjamin Van Roy<br />

We propose an approach to counterfactual analysis of securities exchanges that<br />

can be applied to predict the impact of proposed regulatory changes. We conduct<br />

an empirical case study in which we predict the impact of a historical tick size<br />

change on exchange efficiency and compare predictions to what can be inferred<br />

from subsequent data.<br />

3 - Disentangling Price Impact from Alpha<br />

Mehmet Saglam, Columbia University, New York, NY,<br />

United States of America, MSaglam13@gsb.columbia.edu,<br />

Ciamac Moallemi, Michael Sotiropoulos<br />

Motivated by the performance measurement literature in active portfolio<br />

management, we are interested in attributing the price changes observed during<br />

an execution of a large trade between the client’s short term predictive ability,<br />

alpha view, and the broker’s price impact. Using execution data with a large<br />

universe of clients, we show that incorporating client’s alpha view drastically<br />

increases the explanatory power of existing models and enables to accurately<br />

estimate the price impact.<br />

4 - Optimal Trade Execution using Limit Order Book Information<br />

Rolf Waeber, Cornell University, 206 Rhodes Hall, Ithaca, NY,<br />

14853, United States of America, rw339@cornell.edu,<br />

Sasha Stoikov<br />

We consider an asset liquidation problem at the market microstructure level,<br />

given observations of the limit order book. The optimization is formulated in<br />

terms of a sequence of stopping times, at which we submit market sell orders. We<br />

describe the shape of the trade and no trade regions for different price and latency<br />

assumptions. In the empirical section, we show that our policy signicantly<br />

outperforms a benchmark TWAP algorithm on US treasury bonds.<br />

<strong>Sunday</strong>, 1:30pm - 3:00pm<br />

■ SC01<br />

01- West 101- CC<br />

Optimization in Data Mining<br />

Sponsor: Optimization/Global Optimization<br />

Sponsored Session<br />

Chair: Onur Seref, Assistant Professor, Virginia Tech, 1007 Pamplin<br />

Hall, Blacksburg, VA, 24061, United States of America, seref@vt.edu<br />

1 - How to Reverse-Engineer Quality Rankings<br />

Cynthia Rudin, Assistant Professor, Massachusetts Institute of<br />

Technology, 77 Massachusetts Avenue, Cambridge, MA,<br />

United States of America, rudin@mit.edu, Michael Cavaretta,<br />

Gloria Chou, Robert Thomas, Allison Chang<br />

A good or bad product quality rating can make or break an organization.<br />

However, the notion of “quality” is often defined by an independent rating<br />

company that does not make the formula for ranking products public. We provide<br />

a machine learning approach for “reverse-engineering” a rating company’s<br />

proprietary model as closely as possible.<br />

INFORMS Phoenix – 2012<br />

104<br />

2 - A Probabilistic Model for Assessing the Mortality Risk in<br />

Post-operative Patients<br />

Dmytro Korenkevych, 372 Maguire Village, Apt. 1, Gainesville, FL,<br />

32603, United States of America, dmitriy@ufl.edu, Petar<br />

Momcilovic, Panos Pardalos<br />

We used a probabilistic model based on Bayesian learning and optimization<br />

techniques to estimate the mortality risk in post-operative patients. The model<br />

incorporates discrete and continuous risk factors and provides a probabilistic score<br />

associated with the risk. The feature selection procedure was applied in order to<br />

discard irrelevant risk factors and 70/30 cross-validation analysis was performed<br />

to estimate the accuracy of the model.<br />

3 - Information-Theoretic Learning for Stimulus-specific<br />

Clustering with fMRI<br />

Chun-An (Joe) Chou, University of Washington, 3900 Stevens<br />

Way, Seattle, WA, United States of America, joechou@uw.edu,<br />

Kittipat “Bot” Kampa, Art Chaovalitwongse<br />

Multi-Voxel Pattern Analysis (MVPA) is a popular approach for cognitive<br />

recognition with functional MRI (fMRI), as it is consistent with a neural system<br />

that mental operations/representations are instantiated in a neural population<br />

code spanning multiple voxels. In this work, we employ an unsupervised<br />

clustering with an information-theoretic measure to identify the spatial patterns<br />

of voxels in response to stimuli. The results illustrate that there are specific<br />

clusters for different stimuli.<br />

4 - Optimization Models for Predicting the Antigenic Variants of<br />

Influenza A/H3N2 Virus<br />

Serdar Karademir, University of Pittsburgh, 1048 Benedum Hall,<br />

Pittsburgh, United States of America, sek73@pitt.edu<br />

We use the pairwise amino acid sequence comparison of influenza strains and the<br />

antigenic distance between each pair as input for a classification model to identify<br />

immunodominant positions that cause antigenic variety. The performance of the<br />

model is evaluated through cross validation where cross validation is modeled as<br />

an optimization program that minimizes the misclassification error. Comparison<br />

to results of existing classification methods in literature is also provided.<br />

■ SC02<br />

02- West 102 A- CC<br />

DA Entrepreneurs Speak: Challenges and<br />

Opportunities in Building Decision Analysis<br />

Based Businesses<br />

Sponsor: Decision Analysis<br />

Sponsored Session<br />

Chair: Chris Dalton, CEO, Syncopation Software, 6 State Street,<br />

Suite 402, Bangor, ME, 04401, United States of America,<br />

cdalton@syncopation.com<br />

1 - Tales from the Decision Analysis Industrial Complex<br />

Chris Dalton, CEO, Syncopation Software, 6 State Street,<br />

Suite 402, Bangor, ME, 04401, United States of America,<br />

cdalton@syncopation.com<br />

This talk will define what it means to be a Decision Analysis based business, and<br />

give examples of successful and unsuccessful DA business models. At the end of<br />

the session, we will have a panel discussion with the speakers and other members<br />

of the DA business community.<br />

2 - Building Decision Analysis Based Businesses<br />

Carl Spetzler, CEO, Strategic Decisions Group, 745 Emerson Street,<br />

Palo Alto, CA, 94301, United States of America, cspetzler@sdg.com<br />

As an early member of the original Decision Analysis Group at SRI Internaional<br />

and then one of the founders of SDG, I have participated in and observed about a<br />

dozen of start-up companies based on the power of DA. In this session, I will<br />

share my observations from the successes and failures of these entrepreneurial<br />

efforts.<br />

3 - Business Analytics, Information Technology, and Decision<br />

Analysis<br />

Don Kleinmuntz, Exec VP & Cofounder, Strata Decision<br />

Technology, 200 E Randolph St 49th Floor, Chicago, IL, 60601,<br />

United States of America, dnk@strata-decision.com<br />

Business Analytics is a huge wave that has overtaken a number of industries and<br />

is guiding the development of IT infrastructure in many others. There is a genuine<br />

opportunity to embed decision analysis tools and processes in that infrastructure<br />

and create tremendous impact.


4 - Panel Discussion: Challenges and Opportunities for<br />

DA Businesses<br />

Moderator: Chris Dalton, CEO, Syncopation Software, 6 State<br />

Street, Suite 402, Bangor, ME, 04401, United States of America,<br />

cdalton@syncopation.com, Panelists: Carl Spetzler,<br />

Don Kleinmuntz, Terry Bresnick, Jack Kloeber<br />

The speakers and other members of the DA business community will discuss the<br />

present business environment, taking questions from the audience as time allows.<br />

■ SC03<br />

03- West 102 B- CC<br />

Decision Models in Public Health<br />

Sponsor: Decision Analysis<br />

Sponsored Session<br />

Chair: Ozgur Araz, Assistant Professor, University of Nebraska Medical<br />

Center, Nebraska Medical Center, Omaha, NE, 68198-4365,<br />

United States of America, ozgur.araz@unmc.edu<br />

1 - Multiplicative Utilities for Health and Consumption<br />

Sam Bodily, John Tyler Professor of Business Administration,<br />

University of Virginia, Darden Business School, 100 Darden<br />

Boulevard, Charlottesville, VA, 22903, United States of America,<br />

BodilyS@virginia.edu, Casey Lichtendahl<br />

Two new multiplicative utilities offer correlation aversion and other advantages<br />

over an additive. They extend the QALY model. For constant health and<br />

consumption streams, they reduce to a double exponential utility in life duration,<br />

which can have risk aversion, decreasing absolute risk aversion, increasing<br />

relative risk aversion, as well as standard gamble probabilities (proportional time<br />

tradeoffs) that increase (decrease) in life duration and that exceed proportional<br />

time tradeoffs.<br />

2 - Determining Optimal Therapy for Diabetic Patients. Evidence<br />

from the U.S. Department of Veteran Affairs<br />

Vishal Ahuja, PhD Candidate, University of Chicago, Booth<br />

Business School, Chicago, IL, 60637, United States of America,<br />

vahuja@chicagobooth.edu, John Birge<br />

We investigate various treatments for Type 2 Diabetes in adults using data from<br />

the Veterans Health Administration. We analyze dynamic patterns of glucose<br />

lowering therapies, and evaluate the risks of associated diabetes outcomes. We<br />

propose a predictive model to evaluate effectiveness of various glucose-lowering<br />

therapies and recommend optimal treatment based on patient characteristics. The<br />

paper addresses confounding measures such as physician bias and unobservable<br />

patient characteristics.<br />

3 - Robust Design of a Cost-effective Diabetic Retinopathy<br />

Screening Program with Design of Experiments<br />

Irene Vidyanti, University of Southern California, Los Angeles, CA,<br />

United States of America, irenevidyanti@gmail.com, Shinyi Wu<br />

This paper demonstrates the use of Design of Experiments (DoE) coupled with<br />

simulation to design a robust and cost-effective public health intervention<br />

systematically, using the design of a Diabetic Retinopathy screening program as<br />

illustration. Optimum input factor settings are determined to find settings that<br />

achieve cost-effectiveness. Then, robust parameter design is used to find settings<br />

for a robust program by treating uncertain variables - such as screening<br />

compliance - as noise factors.<br />

4 - Aversion to Health Inequalities in Healthcare Prioritisation:<br />

A Multiobjective Perspective<br />

Alec Morton, London School of Economics and Political Science,<br />

Houghton Street, London, WC2A 2AE, United Kingdom,<br />

a.morton@lse.ac.uk<br />

In this paper we discuss the prioritisation of healthcare projects where there is a<br />

concern about health inequalities. Our analysis begins with a standard welfare<br />

economic model of healthcare resource allocation and we show how the problem<br />

can be reformulated as one of finding a particular subset of the class of efficient<br />

solutions to an implied multiobjective optimization problem. We demonstrate our<br />

approach through a worked example of treatment for clinical depression.<br />

INFORMS Phoenix – 2012<br />

105<br />

■ SC04<br />

04- West 102 C- CC<br />

Decision Makers<br />

Contributed Session<br />

SC04<br />

Chair: Rayan Hafiz, Engineering Specialist, Saudi Arabian Oil Company,<br />

Aramco, Dhahran, Saudi Arabia, rayan.hafiz@aramco.com<br />

1 - Customer Experience Optimization: Regaining Control<br />

of the Conversation<br />

Theresa Igharo, GPJ @ IBM, 11301 Burnet Rd., Austin,<br />

United States of America, igharot@us.ibm.com<br />

Today’s consumers have higher expectations of personalization while leaving<br />

tremendous volumes of seemingly unrelated digital ‘fingerprints’ across many<br />

locations. Organizations have been relying on ad-hoc, inefficient and<br />

disconnected set of processes to make crucial decisions; with often, no means to<br />

understand the impact of those decisions. Business analytics accessible to all<br />

decisions makers increases operational agility while providing organizations with<br />

actionable customer insights.<br />

2 - Deciding by Feeling or Calculation<br />

Mark Schneider, University of Connecticut, Uconn School of<br />

Business, 81 Cheney Drive, Storrs, CT, United States of America,<br />

mschneider@business.uconn.edu, Robin Coulter<br />

Affective and cognitive processes are widely recognized to play an important role<br />

in decision making. However, it remains unclear whether general features of a<br />

decision problem can systematically cue one set of processes over another. In this<br />

paper, we introduce and evaluate a mechanism for predicting whether people will<br />

rely on feeling or calculation in a decision task.<br />

3 - Optimizing Portfolios when Dealing with Ranges<br />

Siddhartha Sampath, Arizona State University, 849 W Elna Rae,<br />

Tempe, AZ, United States of America,<br />

Siddhartha.Sampath@asu.edu, Esma Gel, John Fowler, Karl Kempf<br />

We attempt to discuss the product portfolio selection process and demonstrate<br />

how to solve a non-linear knapsack problem when various products have their<br />

values interdependent on each other. When each value of benefit and cost is also<br />

a range the problem is made even harder. We discuss various strategies to address<br />

this problem.<br />

4 - Decoy Effects in Ethical Decision Making<br />

Wenjie Tang, Assistant Professor, IE Business School, Calle de<br />

Maria de Molina, 12, Piso 5, Madrid, Spain, wenjie.tang@ie.edu,<br />

Steffen Keck<br />

We study decoy effects in ethical decision making. Decoys are alternatives whose<br />

presence increases preference for another alternative in the choice set, though<br />

themselves rarely chosen. We consider a scenario where one is facing a choice<br />

between a monetary more beneficial alternative and a more ethical one. We<br />

propose that the presence of decoys make one more likely to choose the ethical<br />

alternative. We believe that such method can be used to induce ethical choice in<br />

various contexts.<br />

5 - Decision Analysis at Work: Making the Case for Strategic<br />

Technology Selection<br />

Rayan Hafiz, Engineering Specialist, Saudi Arabian Oil Company,<br />

Aramco, Dhahran, Saudi Arabia, rayan.hafiz@aramco.com<br />

In this work, we develop a decision analysis model to help the upper<br />

management make the strategic decision for an emerging technology’s<br />

companywide adoption. Such modeling will help understanding the impact of the<br />

decisions related to dealing with the targeted technology and will set the<br />

corporate direction dealing with it for the next 10 years.


SC05<br />

■ SC05<br />

05- West 103 A- CC<br />

Condition-based Maintenance Optimization<br />

Sponsor: Quality, Statistics and Reliability<br />

Sponsored Session<br />

Chair: Hao Peng, Assistant Professor, Eindhoven University of<br />

Technology, Den Dolech 2, Eindhoven, 5612WN, Netherlands,<br />

h.peng@tue.nl<br />

1 - A Condition-Based Maintenance Policy for Multi-Component<br />

Systems with High Setup Cost of Maintenance<br />

Qiushi Zhu, Ir.MSc, TU Eindhoven, De Lismortel, Paviljoen E.9a,<br />

Eindhoven, 5612 AR, Netherlands, q.zhu@tue.nl,<br />

Geert-Jan van Houtum, Hao Peng<br />

We propose a new CBM policy for multi-component systems with stochastically<br />

and continuously deterioration. To reduce the setup cost of maintenance, a joint<br />

maintenance interval is proposed. The optimal maintenance interval and control<br />

limits of components are determined by minimizing the average long-run cost<br />

rate related to maintenance and downtime. Moreover, a numerical study with a<br />

case of wind farm maintenance is performed based on a large number of nonidentical<br />

components.<br />

2 - Health Condition Prediction Accuracy Improvement and<br />

Condition Based Maintenance Optimization<br />

Zhigang Tian, Concordia University, 1515 Ste-Catherine Street<br />

West, Montreal, Canada, tian@ciise.concordia.ca, Bairong Wu<br />

Health condition prediction is a key part for condition based maintenance (CBM).<br />

It is observed that the prediction accuracy improves with the increase of the age<br />

of the component as it approaches the failure time in many applications. In this<br />

paper, we model the relationship between the prediction accuracy and the age of<br />

a component relative to its predicted failure time. A numerical method is<br />

presented to evaluate the cost of the CBM policy.<br />

3 - Condition-Based Maintenance for Degrading Systems under<br />

Dynamic Environments<br />

Xiao Liu, liuxiaodnn_1@hotmail.com, Khalifa N. Al-Khalif,<br />

Abdel Magid Hamouda, Dingguo Hua, David Coit, Elsayed Elsayed<br />

This talk presents an optimum condition-based maintenance policy for degrading<br />

systems under dynamic environments. The degradation is described by a Wiener<br />

process with both degradation rate and diffusion being influenced by system age<br />

and environment condition. We obtain the distribution of the remaining system<br />

life, based on which the dynamic CBM decisions are made.<br />

4 - Statistical Updating of Finite Element Model with Lamb Wave<br />

Sensing Data for Structural Damage Detection<br />

Arda Vanli, College of Engineering, Florida State University, 2525<br />

Pottsdamer St., Tallahassee, FL, 32310, United States of America,<br />

avanli@fsu.edu, Sungmoon Jung<br />

This study proposes a new probabilistic model updating method used to improve<br />

the prediction capability of a finite element analysis (FEA) model of structural<br />

damages with experimental observations from a sensor network. A controlled<br />

damage experiment on a composite panel showed that the proposed model<br />

updating approach achieves a prediction accuracy that is superior to existing<br />

calibration approaches.<br />

■ SC06<br />

06- West 103 B- CC<br />

Advances in Simulation Optimization<br />

Sponsor: Simulation<br />

Sponsored Session<br />

Chair: Jie Xu, Assistant Professor, George Mason University, 4400<br />

University Dr, MS 4A6, GMU Engr Bldg RM2100, Fairfax, VA, 22030,<br />

United States of America, jxu13@gmu.edu<br />

1 - Integer-ordered Simulation Optimization using R-SPLINE<br />

Bruce Schmeiser, Professor, Purdue University, West Lafayette, IN,<br />

47905, United States of America, bruce@purdue.edu,<br />

Honggang Wang, Raghu Pasupathy<br />

We consider simulation-optimization problems where the decision variables are<br />

integer ordered. We develop R-SPLINE—-an algorithm that alternates between a<br />

continuous search and a discrete neighborhood search, to asymptotically identify<br />

a local minimum. R-SPLINE converges almost surely, with exponentially decaying<br />

likelihood of returning an incorrect solution. With no parameter tuning,<br />

R-SPLINE compares favorably with existing algorithms.<br />

INFORMS Phoenix – 2012<br />

106<br />

2 - Rare Event Simulation for Processes Generated via Stochastic<br />

Fixed Point Equations<br />

Jeffrey Collamore, Associate Professor, University of Copenhagen,<br />

Department of Mathematical Sciences, Universitetsparken 5,<br />

Copenhagen, DK-2100, Denmark, collamore@math.ku.dk,<br />

Anand Vidyashankar, Guoqing Diao<br />

Stochastic fixed point equations (SFPEs) arise in a wide variety of applications in,<br />

e.g., insurance, finance, and the analysis of algorithms. A general SFPE has the<br />

form V =_d f(V) (=_d denotes equality in distribution), where the objective is very<br />

often to infer the tail probabilities of V. We present a general importance sampling<br />

algorithm for computing these rare event probabilities, establishing efficiency,<br />

optimality, and sharp estimates for the running time.<br />

3 - The Gradient Oriented Polar Random Search<br />

Loo Hay Lee, Associate Professor, National University of Singapore,<br />

10 Kent Ridge Crescent, Singapore, Singapore,<br />

iseleelh@nus.edu.sg, Haobin Li, Ek Peng Chew<br />

Involving gradient information in a random search is believed to have better<br />

performance than both gradient-based and metaheuristic local search. However,<br />

the main difficulty is to incorporate and control randomness in a direction instead<br />

of a point. This paper makes use of generalized polar coordinates and<br />

corresponding random distributions, so as to design a brand new Gradient<br />

Oriented Polar Random Search (GO-POLARS) that is proved to satisfy the<br />

conditions for strong local convergence.<br />

4 - Gradient-based Adaptive Stochastic Search for<br />

Discrete Optimization<br />

Enlu Zhou, Assistant Professor, University of Illinois at Urbana-<br />

Champaign, University of Illinois, Urbana, 61801,<br />

United States of America, enluzhou@illinois.edu, Xi Chen<br />

We propose a stochastic search algorithm to solve discrete optimization problems<br />

by iteratively generating candidate solutions from a sequence of parameterized<br />

sampling distributions over the solution space. We convert the discrete<br />

optimization problem to an equivalent continuous problem on the parameter<br />

space so that a gradient method can be incorporated to update the parameter of<br />

the sampling distribution. We show the convergence of the algorithm via tools<br />

from stochastic approximation.<br />

■ SC07<br />

07- West 104 A- CC<br />

Joint Session Data Mining/Computational Stochastic<br />

Optimization: Towards Statistical Parsimony in<br />

Adaptive Dynamic Programming<br />

Sponsor: Data Mining & Computational Stochastic Optimization<br />

Sponsored Session<br />

Chair: Victoria Chen, University of Texas at Arlington, Department Ind.<br />

& Manuf. Sys. Engr., Arlington, TX, United States of America,<br />

vchen@uta.edu<br />

1 - Adaptive Value Function Approximation for Continuous-State<br />

Stochastic Dynamic Programming<br />

Prashant Tarun, Assistant Professor, Craig School of Business,<br />

Missouri Western State University, St. Joseph, MO, 64507, United<br />

States of America, ptarun@missouriwestern.edu, Huiyuan Fan,<br />

Victoria Chen<br />

This study presents a sequential method of value function approximation in the<br />

high-dimensional, continuous-state dynamic programming framework. This<br />

method can adaptively determine both sample size and model structure.<br />

Furthermore, we introduce two new algorithms that help implement the adaptive<br />

value function approximation method efficiently.<br />

2 - Deterministic Sampling Designs with Local Methods for<br />

Optimization Problems<br />

Danilo Macciò, National Research Council of Italy, Via De Marini<br />

6, Genova, 16149, Italy, ddmach@ge.issia.cnr.it, Victoria Chen,<br />

Cristiano Cervellera, Diana Martinez<br />

The problem of numerically minimizing a functional cost involves the following<br />

issues: (i) the definition of a sampling of the domain where the functional is<br />

evaluated; (ii) the choice of a class of models to approximate the solution. This<br />

work presents a comparison of performances among several deterministic<br />

sampling designs (low-discrepancy sequences, orthogonal arrays and Latin<br />

hypercubes) in case local models are employed, in different functional<br />

optimization contexts.


3 - Sequential MARS for Optimization Problems<br />

Diana Martinez, The University of Texas at Arlington, 415 Summit<br />

Ave., Apt # 213, Arlington, TX, 76013, United States of America,<br />

diana.martinezcepeda@mavs.uta.edu, Victoria Chen,<br />

Jay Rosenberger<br />

To find a solution for optimization problems, in some cases an iterative method to<br />

sequentially reduce the solution space is required. It is possible then to have<br />

different design configurations for testing that involve the estimation of a<br />

response value. MARS modeling technique has been used as a surrogate method<br />

in such cases. An algorithm that proposes different MARS sequential routines has<br />

been developed and tested.<br />

4 - Global Optimization for a Piecewise Linear Regression<br />

Spline Function<br />

Nadia Martinez, The University of Texas at Arlington, 415 Summit<br />

Ave. Apt. No. 213, Arlington, TX, 76013, United States of America,<br />

nadia.martinezcepeda@mavs.uta.edu, Jay Rosenberger,<br />

Victoria Chen, Diana Martinez<br />

In this research, we optimize a piecewise linear version of a Multivariate Adaptive<br />

Regression Spline (MARS) function subject to constraints that include both linear<br />

regression models and piecewise linear MARS models. A mixed integer<br />

programming (MIP) model is developed and solved using branch-and-bound. The<br />

MIP is adjusted to enable flexibility to handle both continuous and categorical<br />

variables. This method is demonstrated on designing an automotive safety system<br />

for a major US automaker.<br />

■ SC08<br />

08- West 104 B- CC<br />

Joint Session Doing Good with Good OR/SPPSN:<br />

Doing Good with Good OR Competition: Finalist<br />

Presentations II<br />

Cluster: Doing Good with Good OR Student Competition & Public<br />

Programs, Service and Needs<br />

Invited Session<br />

Chair: Susan Martonosi, Harvey Mudd College, Department of<br />

Mathematics, Claremont, CA, United States of America,<br />

martonosi@hmc.edu<br />

1 - Resource-based Patient Prioritization in Mass-casualty<br />

Incidents<br />

Alex Mills, Indiana University Kelley School of Business, 1309 E.<br />

Tenth Street, Bloomington, IN, 47405, United States of America,<br />

millsaf@indiana.edu, Nilay Argon, Serhan Ziya<br />

Mass-casualty triage currently relies on a fixed priority ordering among different<br />

classes of patients and does not explicitly consider resource limitations. The<br />

nominated study separates medical classification from prioritization and<br />

incorporates survival probabilities and resource limitations. Based on analytical<br />

and simulation results, additional lives can be saved by using the proposed<br />

policies to support decisions made by medical providers.<br />

2 - Improving Patient Access to Surgical Care at the Juravinski<br />

Hospital through Informed Decision Making<br />

Daphne Sniekers, PhD Candidate, University of Toronto,<br />

5 King’s College Road, Toronto, ON, M5S 3G8, Canada,<br />

daphne.sniekers@mail.utoronto.ca<br />

A generic simulation-based perioperative decision support tool was implemented<br />

at the Hamilton Health Sciences Juravinski Hospital to demonstrate how changes<br />

to the operating room schedule and resource availability affect patient flow. The<br />

tool was used in negotiations with the various stakeholder groups in order to<br />

come to consensus on changes to implement. The tool provided invaluable<br />

support in their decision-making.<br />

3 - using Simulation Methods to Guide Decision Making of the<br />

Kentucky Cabinet for Health and Family Services<br />

Russell Harpring, University of Louisville, Louisville, KY,<br />

United States of America, russ.harpring@gmail.com<br />

The purpose of this study is to find potential improvements to the intake process<br />

at the Kentucky Cabinet for Health and Family Services (KCHFS) main office in<br />

Louisville using simulation software. KCHFS deals with hundreds of clients every<br />

day, with each client in the system having different needs. By simulating the<br />

process with Arena Software, experiments can be run with real-time data and<br />

solutions found to complex problems involving process flow, staffing, and layout.<br />

INFORMS Phoenix – 2012<br />

107<br />

■ SC09<br />

09- West 105 A- CC<br />

Evolutionary Multi-Criterion Optimization Tutorial<br />

Sponsor: Multiple Criteria Decision Making<br />

Sponsored Session<br />

Chair: Kalyanmoy Deb, Professor, Indian Institute of Technology<br />

Kanpur, Department of Mechanical Engineering, Kanpur, UP, 208016,<br />

India, deb@iitk.ac.in<br />

1 - Statistical Stopping Criteria for a Multiobjective Genetic<br />

Algorithm<br />

Natalia Viktorovna, Analytics Consultant, SAS Institute, 100 Sas<br />

Campus Drive, T6059, Cary, NC, 27513, United States of America,<br />

natalia.viktorovna@sas.com, Reha Uzsoy, Juan Gaytan<br />

In this research we explore the data structure at iterations of a genetic algorithm.<br />

Main objective is the generation of a statistical stopping criterion. We fit a<br />

multivariate distribution to objective function values and estimate the probability<br />

of creating new non-dominated solutions. This probability is used as a stopping<br />

criterion in a modified NSGA II aimed at solving the Multicriteria Project<br />

Scheduling Problem. Computational experimentation was developed to test the<br />

criteria performance.<br />

2 - A Tutorial on Evolutionary Multi-criterion Optimization (EMO)<br />

Kalyanmoy Deb, Professor, Indian Institute of Technology Kanpur,<br />

Department of Mechanical Engineering, Kanpur, UP, 208016,<br />

India, deb@iitk.ac.in<br />

For the past two decades, multi-criterion optimization problems have been<br />

increasingly being solved using evolutionary optimization methods, simply due to<br />

their parallel search and ability to find multiple trade-off solutions in a single<br />

simulation. In this tutorial, we shall present principles of EMO, results on a<br />

number of challenging problems and highlight some recent research challenges.<br />

■ SC10<br />

SC10<br />

10- West 105 B- CC<br />

Probabilistic Constrained Problems with Continuous<br />

Random Variables<br />

Sponsor: Optimization/Stochastic Programming<br />

Sponsored Session<br />

Chair: Andras Prekopa, Professor, RUTCOR, Rutgers University,<br />

640 Bartholomew Road, Piscataway, 08854, United States of America,<br />

prekopa@rutcor.rutgers.edu<br />

1 - Convex Approximations in Stochastic Programming by<br />

Semidefinite Programming<br />

Istvan Deak, Professor, Department of Computer Science, Corvinus<br />

University of Budapest, Hungary, istvan.deak@uni-corvinus.hu,<br />

Imre Polik, Andras Prekopa, Tamás Terlaky<br />

The following question arises in stochastic programming: how can one<br />

approximate a noisy convex function with a convex quadratic function that is is<br />

optimal in some sense. Using several approaches for constructing convex<br />

approximations we present some optimization models yielding convex quadratic<br />

regressions that are optimal approximations in L_1, L_2 and L_infinity norm.<br />

Extensive numerical experiments to investigate the behavior of the proposed<br />

methods are also performed.<br />

2 - Serially Linked Water Reservoir Network Design<br />

Olga Myndyuk, RUTCOR, Rutgers University,<br />

United States of America, olik.myn@gmail.com<br />

In this paper, we find optimal reservoir capacities such that at least k consecutive<br />

periods the demands are met in the course of a given number of periods with a<br />

probability which is greater than or equal to the prescribed probability.<br />

Formulation, mathematical properties and the solution methodology of the model<br />

are given. Numerical example for 2 reservoirs with 8 consecutive out of 24<br />

periods is presented for the model with demand and inflow being normally<br />

distributed random variables.<br />

3 - Solution of a Probabilistic Constrained Stochastic Programming<br />

Problem with Random Technology Matrix<br />

Andras Prekopa, Professor, RUTCOR, Rutgers University, 640<br />

Bartholomew Road, Piscataway, 08854, United States of America,<br />

prekopa@rutcor.rutgers.edu<br />

We formulate and solve a probabilistic constrained problem, where some of the<br />

technology coefficients are normally distributed random variables. The method of<br />

solution combines the supporting hyperplane method and one, originally<br />

designed to solve problems with discrete random variables. Closed form formulas<br />

for the gradient and numerical results will be presented.


SC11<br />

4 - Simultaneous Confidence Intervals for Future Values of a<br />

Stochastic Process<br />

Jinwook Lee, RUTCOR, Rutgers University, 640 Bartholomew<br />

Road, Piscataway, NJ, 08854, United States of America,<br />

jinwook@rci.rutgers.edu, Andras Prekopa<br />

Given a stochastic process with known finite dimensional distributions, we<br />

construct lower and upper bounds for the probability that future values of the<br />

stochastic process run within prescribed limits. For the solution of the problem we<br />

use the technique of the univariate and multivariate discrete moment problem.<br />

Applications and numerical example will be presented.<br />

■ SC11<br />

11- West 105 C- CC<br />

Application of Stochastic Programming II<br />

Contributed Session<br />

Chair: Aaron L. Nsakanda, Associate Professor, Carleton University,<br />

1125 Colonel By Drive, Ottawa, ON, K1S5B6, Canada,<br />

aaron_nsakanda@carleton.ca<br />

1 - Application of Multistage Stochastic Programming Modeling<br />

and Solution Method on Capacity Planning<br />

George Kolomvos, European Dynamics S.A, 209, Kifisias Av.,<br />

Athens, Greece, kolomvos@gmail.com, Georgios Saharidis<br />

We address the problem of capacity planning in a gas distribution network under<br />

uncertain demand and prices. We consider a large number of scenarios claiming<br />

to describe as good as possible the space of demand and prices for gas. We model<br />

the problem as a multistage stochastic problem, where the decision on the first<br />

stage variables - capacities - will have a critical impact for all future stages. The<br />

problem is solved using the nested decomposition method.<br />

2 - Solving the Drift Control Problem<br />

Melda Ormeci Matoglu, Ozyegin University, Kusbakisi Cad No 2,<br />

Altunizade, Istanbul, Turkey, melda.ormeci@ozyegin.edu.tr,<br />

John Vande Vate<br />

We model managing capacity as a Brownian drift control problem. We formulate<br />

an LP and develop a bound for the continuous problem from a dual solution to<br />

the discrete problem. Showing the equivalence between strongly feasible bases<br />

and deterministic unichain policies, we combinatorialize the pivoting process and<br />

solve the LP without computing its coefficients. We develop scheme analogous to<br />

column generation to drive the gap between the discrete approximation and the<br />

continuous problem to zero.<br />

3 - Time Consistency and Risk Averse Dynamic Decision Models:<br />

Interpretation and Practical Consequences<br />

Davi Valladão, IBM Research/PUC-Rio, Av. Pasteur, 138/146<br />

Botafogo, Rio de Janeiro, Brazil, davimv@br.ibm.com,<br />

Alexandre Street, Birgit Rudloff<br />

We discuss a CVaR based portfolio selection problem and compare a time<br />

consistent formulation to an inconsistent one. We develop a new way of<br />

measuring the impact of an inconsistent policy on the objective function. We<br />

present a sensitivity analysis by computing this impact for different planning<br />

horizons and risk aversion levels. Finally, we develop a suitable economic<br />

interpretation for its recursive objective function based on the certainty<br />

equivalent of the related preference function.<br />

4 - Contracts with Options in Loyalty Reward Programs Supply<br />

Chain<br />

Aaron L. Nsakanda, Associate Professor, Carleton University,<br />

1125 Colonel By Drive, Ottawa, ON, K1S5B6, Canada,<br />

aaron_nsakanda@carleton.ca, Yuheng CAO, Moustapha Diaby<br />

We explore the issue of whether an option mechanism is a viable alternative to<br />

help hedge against demand uncertainties in a Loyalty Reward Programs<br />

enterprise-led supply chain. A two-stage stochastic linear programming with<br />

simple recourse model is developed as well as a solution procedure based on the<br />

sampling average approximation scheme. Our preliminary numerical result will<br />

be reported.<br />

5 - Optimal Control of Production-inventory Systems with<br />

Multiple Facilities<br />

Mohsen Elhafsi, Professsor, University of California, School of<br />

Business Administration, Riverside, CA, 92521,<br />

United States of America, mohsen.elhafsi@ucr.edu, Xi Chen<br />

We study a single-product production-inventory make-to-stock system with<br />

identical production facilities with no order cancellations. Demand is backlogged<br />

if not satisfied immediately. The objective is to control the number of production<br />

facilities to be used at as well as the inventory level so as to minimize the total<br />

production, holding and backlog costs. We show that the optimal policy is defined<br />

by a set of inventory levels and a set of facilities activate-up-to levels for facilities.<br />

INFORMS Phoenix – 2012<br />

108<br />

■ SC12<br />

12- West 106 A- CC<br />

Approximate Dynamic Programming and Discrete<br />

Optimization<br />

Sponsor: Optimization/Integer Programming<br />

Sponsored Session<br />

Chair: Alejandro Toriello, Assistant Professor, Industrial and Systems<br />

Engineering, University of Southern California, 3715 McClintock Ave,<br />

GER 240, Los Angeles, CA, 90089, United States of America,<br />

toriello@usc.edu<br />

1 - Patient Admission and Scheduling under Multiple<br />

Resource Constraints<br />

Christiane Barz, Assistant Professor, UCLA Anderson School of<br />

Management, 110 Westwood Plaza, Los Angeles, United States of<br />

America, christiane.barz@anderson.ucla.edu, Kumar Rajaram<br />

We consider a patient admission problem to a hospital with multiple potential<br />

bottlenecks (e.g. beds and OR). While there is an uncontrolled arrival process of<br />

emergency patients, the hospital has the freedom to postpone or even reject the<br />

admission of non-emergency patients. We model the control process as a Markov<br />

Decision Process and suggest price-directed heuristics.<br />

2 - Dynamic Software Release Management<br />

Angelo Mancini, PhD. Student, University of Chicago Booth<br />

School of Business, 5807 South Woodlawn Ave., Chicago, United<br />

States of America, amancini@chicagobooth.edu, Dan Adelman<br />

Software release management is the process by which firms decide on the timing,<br />

composition and development schedule of their future releases. We construct a<br />

semi-Markov decision process (SMDP) that models these decisions in the<br />

presence of a stochastically improving competitor. We then formulate the static<br />

problem as a mixed integer nonlinear program, whose parameters we obtain by<br />

making a value function approximation in our SMDP. We report numerical<br />

results.<br />

3 - Computing Bounds and Solutions to the Traveling Salesman<br />

Problem with Approximate Linear Programming<br />

Michael Poremba, PhD. Student, Industrial and Systems<br />

Engineering, University of Southern California, 3715 McClintock<br />

Ave., GER 240, Los Angeles, CA, 90089, United States of America,<br />

poremba@usc.edu, Alejandro Toriello<br />

We study the asymmetric traveling salesman problem (TSP) using approximate<br />

linear programming (ALP) to restrict the dynamic programming formulation. The<br />

second author has previously applied ALP to the TSP to obtain a nested family of<br />

polyhedral lower bounds. We discuss two computational methods for solving<br />

these formulations, constraint generation and a primal-dual procedure. We also<br />

present a price-directed tour generation algorithm that uses ALP solutions as<br />

approximate costs-to-go.<br />

4 - A Dynamic Traveling Salesman Problem with Stochastic<br />

Arc Costs<br />

Alejandro Toriello, Assistant Professor, Industrial and Systems<br />

Engineering, University of Southern California, 3715 McClintock<br />

Ave., GER 240, Los Angeles, CA, 90089, United States of America,<br />

toriello@usc.edu, William Haskell, Michael Poremba<br />

We propose a dynamic TSP with stochastic arc costs and use approximate linear<br />

programming to obtain a semi-infinite linear programming lower bound. The<br />

bound requires only expected costs and the support set, and is valid for any<br />

distribution with these parameters. Though NP-hard for general support sets, we<br />

show that the bound can be solved efficiently for polytopes with polynomially<br />

many extreme points and hyper-rectangles. We analyze the price-directed policy<br />

and derive performance guarantees.


■ SC13<br />

13- West 106 B- CC<br />

Mathematical Programming and Applications<br />

Sponsor: Optimization/Linear Programming and Complementarity<br />

Sponsored Session<br />

Chair: Hande Benson, Associate Professor, Drexel University,<br />

Department of Decision Sciences, 3141 Chestnut Street, Philadelphia,<br />

PA, 19104, United States of America, hvb22@drexel.edu<br />

1 - High-contrast Imaging via Fast Fourier Optimization<br />

Robert Vanderbei, Professor, Princeton University, Operations<br />

Research & Financial Engineer, 209 Sherrerd Hall, Princeton, NJ,<br />

08544, United States of America, rvdb@princeton.edu<br />

Many interesting and fundamentally practical optimization problems involve<br />

constraints on the Fourier transform of a function. Because the fast Fourier<br />

transform is recursive, it is difficult to embed into a linear optimization problem.<br />

However, one can adapt the main idea behind the fast Fourier transform so as to<br />

make it encodable as constraints in an optimization problem. We demonstrate on<br />

a real-world problem from the field of high-contrast imaging.<br />

2 - Incorporation of Delivery Times in Gamma Knife(R)<br />

Perfexion(TM) Treatment Optimization<br />

Hamid Ghaffari, PhD Candidate, University of Toronto, 5 King’s<br />

College Rd, MIE Department, Toronto, ON, M5S 3G8, Canada,<br />

ghaffari@mie.utoronto.ca, Mark Ruschin, Dionne Aleman,<br />

David Jaffray<br />

Although the use of mathematical optimization techniques can greatly improve<br />

the quality of treatment plans in various radiation therapy treatment settings, one<br />

complication is the potentially clinically unrealistic nature of optimized<br />

treatments. The difficulty arises from two factors: (1) machine limitations that<br />

govern the minimum amount of radiation delivery time, and (2) long treatment<br />

times due to the complexity of optimized treatments. In the first scenario, if a<br />

particular configuration of the radiation delivery device is used, then it typically<br />

must deliver radiation for a minimum length of time. Incorporation of such<br />

requirements in a mathematical model generally requires additional constraints<br />

and binary variables, increasing the difficulty of the optimization. In the second<br />

scenario, mathematically optimized treatments commonly assign (small amounts<br />

of) radiation to be delivered from many configurations, drastically increasing the<br />

time needed to deliver the treatment (beam-on time). We examine these two<br />

issues within the penalty-based sector-duration optimization model for Gamma<br />

Knife(R) Perfexion(TM) (Elekta, Stockholm, Sweden) and the combined sectorduration<br />

and isocentre optimization model to reduce beam-on time and to ensure<br />

that machine limitations regarding delivery times are met.<br />

3 - Portfolio Optimization with Cone Constraints and<br />

Discrete Decisions<br />

Umit Saglam, Drexel University, LeBow College of Business,<br />

Philadelphia, 19104, United States of America, us26@drexel.edu<br />

We consider a portfolio optimization problem where the investor’s objective is to<br />

choose a trading strategy that maximizes expected return penalized by transaction<br />

costs. We include portfolio diversification constraints in our single and<br />

multiperiod models. The overall problem is a mixed-integer second-order cone<br />

programming problem, which we solve with the Matlab-based solver MILANO.<br />

This talk will focus on the solution and warm-start of the second-order cone<br />

programming subproblems.<br />

4 - MILANO: Mixed-Integer Linear and Nonlinear Optimizer<br />

Hande Benson, Associate Professor, Drexel University, Department<br />

of Decision Sciences, 3141 Chestnut Street, Philadelphia, PA,<br />

19104, United States of America, hvb22@drexel.edu<br />

We will present the primal-dual penalty interior-point method that is<br />

implemented in MILANO for providing warmstart capabilities and robustness in a<br />

linear and mixed-integer linear programming framework. Extensions to cone<br />

programs and nonlinear programming problems will be explored.<br />

■ SC14<br />

14- West 106 C- CC<br />

Applications of Project Management<br />

Contributed Session<br />

Chair: Hiroko Nakamura, Project Researcher, The University of Tokyo,<br />

7-3-1 Hongo Bunkyoku, Tokyo, Japan, techhn@mail.ecc.u-tokyo.ac.jp<br />

1 - Change’s Timing and Cost Discrepancies in Public<br />

Project Procurement<br />

Jane Park, The George Washington University, 2201 G Street NW<br />

Duques Hall, Washington, DC, 20052, United States of America,<br />

janepark@gwu.edu<br />

The purpose of this study is to help manage changes better in public project<br />

procurement. Using the data from transportation projects in Florida, this study<br />

INFORMS Phoenix – 2012<br />

109<br />

classifies the reasons of change order and investigates how differently each reason<br />

affect the cost discrepancy between the original contract amount and the final<br />

payment depending on its timing of occurrence over the project duration.<br />

2 - A Study to Identify Key Factors Influencing Cost Overruns in<br />

Medium-scale Infrastructural and Social Projects<br />

Mohamed Salem, Senior Civil Engineer Specialist, Islamic<br />

Development Bank-Special Assistance Division, P.O. Box: 5925,<br />

Jeddah, 21432, Saudi Arabia, msalm@isdb.org, Alaa Elwany,<br />

Hamdy Elwany<br />

The accuracy of cost estimation for infrastructural and social projects is one of the<br />

key challenges that faces governments and funding organizations. Cost estimates<br />

during feasibility studies involve many assumptions and inherent uncertainties.<br />

The study analyzed the key factors that contribute to cost escalation. In particular,<br />

the study used multiple regression analysis to develop an empirical formula for<br />

accurately predicting cost overrun/ underrun during the project implementation.<br />

The study is based on analyzing data from 110 real-world projects implemented<br />

over the past decades.<br />

3 - Solving the Resource Investment Problem with Time Lags<br />

(RIP/max) via Mixed Integer Programming<br />

Juan D. Palacio, Instructor, Universidad de los Andes,<br />

Departamento de Ingenieria Industrial, Carrera 1 Este # 19 A-40,<br />

Bogota, Colombia, jd.palacio34@uniandes.edu.co,<br />

Sebastian Brunal, Andrés L. Medaglia<br />

The RIP/max is an NP-Hard problem that has been solved mainly using heuristics.<br />

We tackle this problem using a mixed integer programming model with proven<br />

success on variants of the project selection and resource constrained scheduling<br />

problems. We found new best known solutions and optimality certificates for<br />

instances of up to 30 projects. We also report new lower bounds and show how<br />

this formulation adapts to the resource investment problem (RIP).<br />

4 - Survey and Evaluation of Bibliometrics Methods for Research<br />

Planning and Technology Management<br />

Hiroko Nakamura, Project Researcher, The University of Tokyo,<br />

7-3-1 Hongo Bunkyoku, Tokyo, Japan, techhn@mail.ecc.utokyo.ac.jp,<br />

Yuya Kajikawa, Shinji Suzuki<br />

Managers and researchers of research institutes and industries were surveyed to<br />

determine the needs and expectation of bibliomentrics development for research<br />

planning and technology management. Based on actual problems, patent analysis<br />

methods to produce technology overviews of an industry and detection of<br />

emerging technology and of technology links between automobile and aviation<br />

industries were studied and evaluated.<br />

■ SC15<br />

SC15<br />

15- West 202- CC<br />

Software Demonstration<br />

Invited Session<br />

1 - GAMS Development Corporation – Deploying Your Application<br />

Built Around GAMS<br />

Michael Bussieck, GAMS Development, 1217 Potomac Street NW,<br />

Washington, DC, 20007, United States of America,<br />

mbussieck@gams.com, Lutz Westermann<br />

We will demonstrate the development of an application built around GAMS and<br />

its effortless deployment. Furthermore, we will show recent enhancements to the<br />

GAMS system.<br />

2 -Salford Systems - Real-World Data Analysis<br />

Mikhail Golovnya, Senior Scientist, Salford Systems, 9685 Via<br />

Excelencia, Ste. 208, San Diego CA 92126, United States of<br />

America, dsprague@schwartzmsl.com<br />

This demo, intended for the modeler wanting to apply data mining methodology,<br />

will emphasize real-world data analysis. The main concepts behind well-known<br />

data mining algorithms will be discussed: CART®, MARS® automated non-linear<br />

regression, TreeNet® stochastic gradient boosting, RandomForests®, GPS<br />

Generalized Pathseeker, ISLE Importance Sampled Learning Ensembles and the<br />

Rulefit Rule Extraction Engine. We will discuss what is novel in the software,<br />

cover implementation, and show where the software fits in terms of other data<br />

mining software methods.


SC16<br />

■ SC16<br />

16- West 207- CC<br />

Humanitarian Logistics<br />

Cluster: Tutorials<br />

Invited Session<br />

Chair: Ozlem Ergun, Associate Professor, Georgia Institute of<br />

Technology, ndustrial and Systems Engineering, Atlanta, GA, United<br />

States of America<br />

1 - Humanitarian Logistics<br />

Ozlem Ergun, Georgia Institute of Technology, 765 Ferst Dr NW,<br />

Atlanta, GA, United States of America, oergun@isye.gatech.edu,<br />

Pinar Keskinocak, Julie L. Swann<br />

The increase in natural and man-made disasters in the recent years has<br />

highlighted challenging problems in humanitarian operations, in addition to<br />

major long-term humanitarian development challenges. Humanitarian logistics<br />

plays an important role in preparing for, responding to, and recovering from<br />

sudden-onset disasters and addressing long-term development issues. The<br />

management of humanitarian logistics operations involves many challenges such<br />

as conflicting objectives from multiple stakeholders, coordination and<br />

collaboration, high uncertainty, and scarcity of resources. In this tutorial, we<br />

provide an introduction to humanitarian logistics and its main application areas<br />

while outlining current research trends and the major challenges faced in the area<br />

today. We also present four decision aid tools addressing typical applications of<br />

humanitarian logistics: network design for donated human breast milk delivery in<br />

South Africa, port simulation and shipment scheduling for a large international<br />

agency, demand estimation and emergency procurement for CARE, and postdisaster<br />

medical response under accessibility issues. In presenting these decision<br />

aid tools, we aim to underline the differences in issues arising from sudden-onset<br />

disasters and long-term development problems, various stages of the life cycle of<br />

disasters, and different decision levels, while also pointing to general aspects in<br />

modeling humanitarian logistics problems.<br />

■ SC17<br />

17- West 208 B- CC<br />

SpORts II<br />

Sponsor: SpORts<br />

Sponsored Session<br />

Chair: Dan Finkel, Technical Staff, Massachusetts Insitute of<br />

Technology, Lincoln Laboratory, 244 Wood Street, Lexington, MA,<br />

02420, United States of America, dfinkel@ll.mit.edu<br />

1 - Optimizing an NBA Team’s Approach to Free Agency using the<br />

Knapsack Problem<br />

Sam Kirshner, Queen’s School of Business, 143 Union Street,<br />

Kingston, Canada, skirshner@business.queensu.ca<br />

This paper models an NBA team’s approach free agency as a knapsack problem.<br />

The free agents comprise the items and the team’s cap space corresponds to the<br />

size of the knapsack. As free agents are signed, both the talent pool to fill the<br />

team’s needs and the money in the market decreases. Thus, the optimal free<br />

agency strategy must considers the trade-off of losing a player to a competitor and<br />

acquiring the player at a price that preserves as much cap space as possible to sign<br />

additional players.<br />

2 - Bicycle Tours: Modeling the Perceived Exertion of a Daily Path<br />

Katherine Carl, Graduate Associate, University of Arizona, 1130 E.<br />

Helen Street, P.O. Box 210108, Tucson, AZ, 85721,<br />

United States of America, kcarl@email.arizona.edu, Moshe Dror<br />

Bicycling has garnered interest in recent years. Perceived exertion is an important<br />

consideration when selecting bicycling tours. We propose a model for generating<br />

measures of perceived exertion for bicycling tours for 5 categories of riders. We<br />

present results of a survey designed to verify the accuracy of our model and<br />

demonstrate a good fit with exertion values reported by cyclists.<br />

3 - Determining NHL Player Types and Point Shares<br />

Timothy Chan, Assistant Professor, University of Toronto,<br />

5 King’s College Rd, Toronto, Canada, tcychan@mie.utoronto.ca,<br />

David Novati<br />

In this talk, we present a methodology using clustering, projection and regression<br />

analyses to determine distinct NHL player types and measure players’ individual<br />

contributions to overall team performance. We apply our method to historical<br />

NHL player data at the season level. Initial results suggest that our point share<br />

values are aligned with perceptions of “goodness” of a hockey player. In<br />

particular, players with the highest point share values tend to win major NHL<br />

awards.<br />

INFORMS Phoenix – 2012<br />

110<br />

■ SC18<br />

18- West 208 A- CC<br />

Methodologies for Network Optimization<br />

Contributed Session<br />

Chair: Paul Grigas, Graduate Student, Massachusetts Institute of<br />

Technology, 23 Gorham St., Somerville, MA, 02144,<br />

United States of America, pgrigas@mit.edu<br />

1 - Self-learning Injection-locked Laser Network for Solving<br />

NP-complete Problems<br />

Kai Wen, Edward L. Ginzton Laboratory, Stanford University,<br />

Stanford, CA, 94305, United States of America,<br />

kaiwen@stanford.edu, Kenta Takata, Shoko Utsunomiya,<br />

Yoshihisa Yamamoto<br />

NP-complete problems are important and difficult problems. Here we show that a<br />

novel computation machine based on injection-locked laser network and selflearning<br />

algorithm, driven by random phase noise, can solve NP-complete Ising<br />

problems in polynomial time. The stochastic simulation on MAX-CUT problems<br />

on cubic graph and the two-layer lattice problems demonstrates its polynomial<br />

time complexity up to problem size of 800 nodes.<br />

2 - A Parallel Decomposition-based Methodology for<br />

Network Optimization<br />

Dia St. John, INEG Department, University of Arkansas,<br />

Fayetteville, AR, 72701, United States of America,<br />

destjohn@uark.edu, Chase Rainwater, J. Cole Smith<br />

This work focuses on the development of parallel techniques that provide<br />

computational capabilities to solve large-scale network interdiction models. By<br />

dictating the interdiction state of a subset of system arcs, each parallel iteration<br />

focuses on determining the most disruptive decisions for a subset of the network.<br />

The use of message passing between these parallel structures facilitates efficient<br />

communication between simultaneous iterations and contributes to the<br />

algorithmic effectiveness.<br />

3 - Circuit Bases and Multicommodity Flows<br />

J N Hagstrom, Professor, University of Illinois at Chicago,<br />

Information & Decision Sciences, 601 S Morgan, Chicago, IL,<br />

60607-7124, United States of America, hagstrom@uic.edu<br />

We show that a basis for a capacitated multicommodity flow on a graph can be<br />

identified as a set of spanning trees, one for each commodity and one for the<br />

slacks, plus a circuit basis of the graph, with each circuit assigned to a single<br />

commodity or to the slacks. Work is in progress to develop a simplex algorithm<br />

implementation using this new insight.<br />

4 - An Algorithm for Convex Non-separable Network Flow<br />

Problems<br />

Trung Hieu Tran, Research Fellow, National University of<br />

Singapore, Industrial and Systems Engineering Dept, 1<br />

Engineering Drive 2, Singapore, 117576, Singapore,<br />

isetth@nus.edu.sg, Kwong Meng Teo<br />

While algorithms for multi-commodity network flows often assume linear or<br />

convex separable costs, non-separability is often a more realistic assumption. We<br />

propose a modified gradient projection-based algorithm for this more general class<br />

of problems, and present its performance using standard test cases. Empirical<br />

studies also show that a convex non-separable network flow problem can be<br />

handled if the same problem, but with linear cost, can be solved using CPLEX.<br />

5 - Proximal Subgradient and Dual Averaging for Sequential<br />

Decision-making and Non-smooth Optimization<br />

Paul Grigas, Graduate Student, Massachusetts Institute of<br />

Technology, 23 Gorham St., Somerville, MA, 02144,<br />

United States of America, pgrigas@mit.edu, Robert Freund<br />

We analyze and show interconnections between prox subgradient and dual<br />

averaging methods for both sequential decision making and non-smooth convex<br />

optimization. Our sequential decision-making problem generalizes the problem<br />

addressed in the Hedge Algorithm as studied by Baes and Burgisser, and our<br />

framework provides a new interpretation and extensions of the algorithm<br />

AdaBoost. Lastly, we examine connections between various first-order method,<br />

and propose new first-order methods as well.


■ SC19<br />

19- West 211 A- CC<br />

Joint Session Healthcare Logistics/SPPSN: Routing<br />

Problems in Healthcare Operations II<br />

Cluster: Healthcare Logistics & Public Programs, Service and Needs<br />

Invited Session<br />

Chair: Burcu Keskin, University of Alabama, Alston Hall, Box: 870226,<br />

Tuscaloosa, AL, 3587-0226, United States of America,<br />

bkeskin@cba.ua.edu<br />

1 - A Multi-level Location-allocation Problem in Human Milk<br />

Banking Network Expansion<br />

Melih Çelik, Georgia Institue of Technology, 765 Ferst Dr NW,<br />

Atlanta, GA, 30332, United States of America,<br />

melihcelik@gatech.edu, Wenwei Cao, Nadia Viljoen,<br />

Julie L. Swann, Ozlem Ergun<br />

Motivated by a project on a human milk bank reserve, we study a large-scale<br />

multi-level location-allocation problem for supply chain network expansion. With<br />

limited resources, equitable access to breast milk for newborn infants is one of the<br />

main concerns. We incorporate several fairness metrics into the model. Under<br />

certain metrics, the MIP becomes intractable. We develop efficient heuristics to<br />

find good solutions and conduct comparative computational analysis of different<br />

fairness metrics.<br />

2 - Enabling Greater Access to Home Meal Delivery<br />

Maciek Nowak, Associate Professor, Loyola University Chicago,<br />

1 E. Pearson, Chicago, IL, 60611, United States of America,<br />

mnowak4@luc.edu, Mike Hewitt, Leonardo Gala<br />

Meals on Wheels relies on a volunteer workforce to deliver meals to<br />

approximately one million homebound citizens in the US. One strategy for<br />

accommodating these requests is to deliver multiple (frozen) meals at a time.<br />

However, the funding agencies and the volunteers value the relationships that are<br />

developed by having a client interact with the same volunteer. We present an<br />

approach to quantify the efficiencies associated with delivering frozen meals while<br />

maintaining volunteer consistency.<br />

3 - An Integrated Patient Transportation and Operating Room<br />

Scheduling Model<br />

Sepehr Nemati Proon, PhD Student, University of Pittburgh, 3700<br />

O’Hara Street, Pittsburgh, PA, 15261, United States of America,<br />

sen12@pitt.edu, Oleg Shylo, Andrew Schaefer, Oleg Prokopyev<br />

We consider a model that integrates the optimal transportation of outpatients<br />

from their residences to a hospital and back using a capacitated fleet of vehicles,<br />

and surgery scheduling in an operating suite. The objective is to minimize the<br />

overall time that patients spend on the road and in the hospital. We formulate<br />

this problem as a mixed integer programming and present a Branch and Price<br />

algorithm to solve it.<br />

4 - Integrated Dispatch and Relocation Model to Minimize<br />

Emergency Vehicle Response<br />

Ibrahim Capar, University of Alabama, Tuscaloosa, AL,<br />

United States of America, icapar@cba.ua.edu, Burcu Keskin, Sharif<br />

Melouk<br />

To prepare for emergency events, EMS managers must address issues related to<br />

emergency vehicle dispatching and relocation. We use an MIP formulation to<br />

model emergency vehicle dispatching and relocation with the goal of minimizing<br />

incident response time while still maintaining adequate network coverage. We<br />

conduct extensive experimentation to examine model performance and glean<br />

managerial insights.<br />

■ SC20<br />

20- West 211 B- CC<br />

Software Demonstration<br />

Invited Session<br />

1 - Spry, Inc. – The Analyst Workbench: Better Data, Faster<br />

Decisions<br />

Todd Jones, Director of Business Solutions, Spry, Inc., Director of<br />

Business Solutions, Sparks, MD, 21152, United States of America,<br />

tjones@spryinc.com<br />

A single hub of integrated data, one that can be sliced however an analyst wants.<br />

The ability to quickly add and integrate new data sources; the ability to use R,<br />

Tableau and other familiar tools. These are the demands of today’s analyst. This<br />

presentation will introduce the role semantic technologies and big data play in<br />

developing this data hub.<br />

INFORMS Phoenix – 2012<br />

111<br />

2. - Oracle - Learn About Oracle Crystal Ball<br />

Michael Franden, Academic & Higher Education Sales Mgr, Oracle,<br />

500 Oracle Parkway, Redwood Shores, CA, 94065, United States of<br />

America, michael.franden@oracle.com<br />

Oracle’s Crystal Ball software is a spreadsheet-based software suite for predictive<br />

modeling, forecasting, Monte Carlo simulation and optimization. Crystal Ball is<br />

used in universities and schools worldwide to teach financial risk analysis,<br />

valuation, engineering, portfolio allocation, cost estimation, and project<br />

management. Join us for an overview of Crystal Ball and our teaching resources.<br />

■ SC21<br />

SC21<br />

21- West 212 A- CC<br />

Modeling and Optimization Techniques for Network<br />

Robustness<br />

Sponsor: Optimization/Networks<br />

Sponsored Session<br />

Chair: Vladimir Boginski, Assistant Professor, University of Florida,<br />

1350 N. Poquito Rd, Shalimar, FL, 32579, United States of America,<br />

boginski@reef.ufl.edu<br />

1 - Reliable Routing under Independent Random Arc Failures and<br />

Algorithms with Scenario Reduction<br />

Qipeng Zheng, Assistant Professor, West Virginia University,<br />

Industrial & Management Systems Engineer, P.O. Box 6070,<br />

Morgantown, WV, 26505, United States of America,<br />

qipeng.zheng@gmail.com, Daniel Simmons<br />

Routing problems have been widely researched in literature. Of particular interest<br />

to this talk is on the stochastic cases of routing, which consider the risk of route<br />

failures. This talk proposes stochastic programming models for routing problems<br />

under independent arc failures. We propose methods which study the dual of the<br />

stochastic programs when the routes are given, and generate efficient cuts for the<br />

original problem to avoid complete enumeration of all outcomes.<br />

2 - Modeling and Analysis of Generalized Path-Restricted Robust<br />

Network Clusters<br />

Alexander Veremyev, NRC Research Associate, Air Force Research<br />

Laboratory, Building 13, 101 West Eglin Boulevard, Eglin AFB, FL,<br />

United States of America, averemyev@gmail.com,<br />

Vladimir Boginski<br />

Short path connectivity between each pair of nodes is an essential network<br />

property in different real-life settings. A k-club may not reflect certain pathconnectivity<br />

requirements, i.e, some important pairs of network components may<br />

be required to have shorter communication paths than others, or to be dependent<br />

on the cluster size. Several possible generalizations of a k-club concept and new<br />

compact linear 0-1 programming models for identifying such network clusters are<br />

discussed in this talk.<br />

3 - Optimal Design and Augmentation of Strongly Attack-Tolerant<br />

Two-Hop Clusters in Directed Networks<br />

Grigory Pastukhov, PhD Student, University of Florida,<br />

303 Weil Hall, Gainesville, FL, 32611, United States of America,<br />

gpastukhov@ufl.edu, Eduardo Pasiliao, Vladimir Boginski,<br />

Alexander Veremyev<br />

We consider the problems of minimum-cost design and augmentation of directed<br />

network clusters that have diameter 2 and maintain the same diameter after the<br />

deletion of up to R nodes and/or arcs anywhere in a cluster. We present provably<br />

tight theoretical bounds and a heuristic algorithm for the considered class of<br />

problems. Computational experiments suggest that the proposed heuristic does<br />

identify high-quality near-optimal solutions.<br />

4 - Transmission Switching in Electric Grids with Uncertain<br />

Line Failures<br />

Oleg Shirokikh, University of Florida, 303 Weil Hall, Gainesville,<br />

FL, 32611, United States of America, olegshirokikh@ufl.edu,<br />

Alexey Sorokin, Vladimir Boginski<br />

We consider the problem of identifying a cost-efficient strategy for transmission<br />

line switching in electric grids under risk considerations associated with uncertain<br />

failures of multiple lines (arcs) in the network. Conditional Value-at-Risk<br />

constraints are utilized to restrict potential losses associated with failure scenarios.


SC22<br />

■ SC22<br />

22- West 212 B- CC<br />

Service and Security<br />

Sponsor: Telecommunications<br />

Sponsored Session<br />

Chair: Hu Hao, Chinese University of Hong Kong, Room 943, 9/F,<br />

Cheng Yu Tung Building, Shatin, N.T., Hong Kong, 999077, China,<br />

huhao@baf.msmail.cuhk.edu.hk<br />

1 - A Portfolio-based Approach for the Analysis of Integrated<br />

Telecommunications Service Providers<br />

Steven Powell, Professor Emeritus, California State Polytechnic<br />

University, Pomona, CIS Department, 3801 West Temple Avenue,<br />

Pomona, CA, 91768, United States of America,<br />

srpowell@csupomona.edu<br />

As their existing domestic and foreign markets mature and emerging market<br />

opportunities dwindle, telecommunications service providers (TSPs) are seeking<br />

growth from consolidating their fixed line and mobile platforms to offer<br />

integrated data, video, and voice services, often in multiple play bundles. This<br />

paper presents a multidimensional technique for analyzing integrated TSPs<br />

strategically based on the degree of market attractiveness and competitive<br />

strength their business portfolios possess.<br />

2 - Analysis of a Threshold-based Node Sleep Scheduling Policy<br />

for Energy Harvesting Sensor Networks<br />

Arupa Mohapatra, PhD Student, Texas A&M University, 3131<br />

TAMU, College Station, TX, 77843, United States of America,<br />

arupa@tamu.edu, Natarajan Gautam<br />

Autonomous wireless sensor networks with energy harvesting nodes are gaining<br />

prominence in long-lived remote surveillance applications. Node sleep scheduling<br />

is a popular approach to ensure “energy-neutral” operation in these networks.<br />

We present a fluid model based analysis of performance of such a network under<br />

a threshold based sleep scheduling policy.<br />

3 - Fast Approximate Choice of Record Length for Large<br />

Encrypted Database<br />

David Shallcross, Applied Communication Sciences, Piscataway,<br />

NJ, 08854, United States of America, dshallcross@appcomsci.com<br />

To conceal actual record lengths in encrypted databases, we consider choosing a<br />

fixed record length. Actual records are to be split and padded to form multiple<br />

records of the chosen length. We want to minimize the total memory consumed.<br />

An exact optimum can be easily be found in time quadratic in the maximum<br />

record length. We now present an approximate algorithm that runs in less time,<br />

and also some results on the sensitivity of this approximation to database updates.<br />

4 - Social Capital and Service Continuity: An Investigation of<br />

Telecom Service<br />

Hu Hao, Chinese University of Hong Kong, Room 943, 9/F, Cheng<br />

Yu Tung Building, Shatin, N.T., Hong Kong, 999077, China,<br />

huhao@baf.msmail.cuhk.edu.hk, Jianmin Jia, Yuho Chung<br />

Telecom service forms social network naturally. Consumer’s perception of its<br />

value depends on social capital in the network. If consumers appreciate the value,<br />

they will pay more attention to service continuity and recover soon after<br />

abnormal status occurs. Using telecom service data, we examine the role of social<br />

capital. The results indicate that network structural properties and reciprocal<br />

social norm have significant impact on consumer’s attention to service continuity<br />

in social network.<br />

■ SC23<br />

23- West 212 C- CC<br />

Edelman 2012 Finalists I<br />

Sponsor: CPMS, The Practice Section<br />

Sponsored Session<br />

Chair: Stephen Graves, Massachusetts Institute of Technology, Sloan<br />

School of Management, 77 Massachusetts Avenue, Cambridge, MA,<br />

02139, United States of America, sgraves@mit.edu<br />

1 - Transformation of HP Business Model through Advanced<br />

Analytics and Operations Research<br />

Suresh Subraman, Hewlett-Packard, San Diego, CA,<br />

United States of America, Suresh.Subramanian@hp.com<br />

So that Hewlett-Packard customers can shop anywhere anytime, HPDirect.com<br />

developed an ECommerce value chain across financial, marketing, warehouse<br />

planning and operations departments. Key drivers impacting online traffic were<br />

identified and quantified by time series forecasts and regression models. Their<br />

holistic customer targeting engine doubled purchase conversion rates and<br />

increased order sizes up to 30% -thanks to Bayesian modeling, Markov analysis<br />

and Linear Discriminant analysis.<br />

INFORMS Phoenix – 2012<br />

112<br />

2 - Delivering Profitable Growth for HPDirect.com using<br />

Operations Research<br />

Arnab Chakraborty, Director, Global Analytics, HP, No. 66/2, Ward<br />

No. 83, Bagmane Tech-Park, Embassy Prime, CV Raman Nagar,<br />

Bangalore, Ka, 560093, India, arnab.chakraborty@hp.com,<br />

Manav Shroff, Rohit Tandon, Girish Srinivasan<br />

HP’s online business, is meant to build robust multi-channel presence given the<br />

evolution in shopping behavior. The business benefitted from OR Solutions that<br />

overcame problems faced along the e-commerce value chain -Traffic Driver<br />

Identification(impacts marketing & budget management),Purchase Pattern<br />

Prediction(effective campaign design) AND Order Forecasting(Optimize<br />

warehouse inventory holding & order fulfillment).Deploying these solutions since<br />

‘09 have driven additional revenue of $117Mn.<br />

3 - Centers for Disease Control and Prevention: Advancing Public<br />

Health and Medical Preparedness<br />

Greg Burel, Center for Disease Control and Prevention,<br />

Washington, DC, United States of America, Greg.Burel@cdc.gov,<br />

Eva Lee<br />

CDC public health experts teamed with operations researchers to devise<br />

sophisticated modeling and computational strategies to improve mass dispensing.<br />

With the powerful information decision-support suite, RealOpt©, expanded<br />

capabilities are identified for those with limited resources and stressed<br />

environments. Over 4,000 public health and emergency directors can now make<br />

rapid and effective interventions for at-risk populations, lessening the subsequent<br />

disease mortality and save money.<br />

■ SC24<br />

24- West 213 A- CC<br />

Data Driven Results and Models in Healthcare<br />

Operations<br />

Sponsor: Health Applications Society<br />

Sponsored Session<br />

Chair: Hari Balasubramanian, Assistant Professor, University of<br />

Massachusetts, 160 Governors Drive, Amherst, MA, 01003,<br />

United States of America, hbalasubraman@ecs.umass.edu<br />

1 - Designing Clinical Trials for Cancer: An Analytics Approach<br />

Stephen Relyea, Massachusetts Institute of Technology, 77<br />

Massachusetts Avenue, Bldg. E40-149, Cambridge, MA, 02139,<br />

United States of America, srelyea@mit.edu, John Silberholz,<br />

Dimitris Bertsimas, Allison O’Hair<br />

We present a data-driven approach for designing new clinical trials for cancer<br />

chemotherapy treatments. Our approach combines (i) text-mining to develop a<br />

database of existing trial results, (ii) statistical modeling to predict outcomes of<br />

new drug combinations, and (iii) optimization models to select novel treatments<br />

that strike a balance between maximizing patient outcomes (exploitation) and<br />

learning new things about treatments that may be useful in the future<br />

(exploration).<br />

2 - Appointment Reminder Systems and Patient Preferences<br />

Nan Liu, Columbia University, 600 W 168th St., Room 603, New<br />

York, NY, 10032, United States of America, nl2320@columbia.edu,<br />

Stacey Finkelstein, Beena Jani, David Rosenthal,<br />

Lusine Poghosyan<br />

We utilized a cross-sectional design where patients ranked various appointment<br />

reminder systems and indicated their usage of technology and familiarity with<br />

other service providers contacting them via text message and e-mail. We found<br />

that patient usage and familiarity of technology are the best predictors of<br />

perceived effectiveness and responsiveness to text message and e-mail reminders.<br />

After these variables are accounted for, age and other demographic variables are<br />

not significant predictors.<br />

3 - using Emprical Data Analysis and Simulation to Improve<br />

Capacity Planning for Inpatient Beds<br />

Asli Ozen, PhD Student, University of Massachusetts Amherst, 160<br />

Governors Drive, Amherst, MA, 01003, United States of America,<br />

aslozen@gmail.com, Hari Balasubramanian<br />

In hospitals nationwide, misaligned bed capacity results in ED crowding and<br />

PACU holds. We used patient admission rates, surgery schedules, bed placement<br />

rules, length of stays and capacity information from Baystate Medical Center<br />

(Springfield, MA) to develop computer based optimization and simulation model<br />

to improve capacity allocation of inpatient beds. Our goal is to provide guidelines<br />

on how hospitals should manage their inpatient bed capacity in the presence of<br />

demand and LOS variability.


4 - using Empirical Data to Classify Patients for Improved<br />

Appointment Scheduling<br />

Hari Balasubramanian, Assistant Professor, University of<br />

Massachusetts, 160 Governors Drive, Amherst, MA, 01003,<br />

United States of America, hbalasubraman@ecs.umass.edu,<br />

Hyun-Jung Oh, Ana Muriel<br />

We analyze patient flow data for 400 patients collected at a family medicine<br />

practice in Massachusetts. We then present an stochastic integer programming<br />

model to schedule appointments to minimize a weighted combination of patient<br />

waiting and provider idle time. The model sequences patient types with different<br />

nurse and physician time requirements and staggers their appointment start times<br />

appropriately while keeping the basic slot structure used by the schedulers at the<br />

practice.<br />

■ SC25<br />

25- West 213 B- CC<br />

Radiation Therapy Treatment Planning II<br />

Sponsor: Health Applications Society<br />

Sponsored Session<br />

Chair: Edwin Romeijn, Professor, University of Michigan, IOE<br />

Department, 1205 Beal Avenue, Ann Arbor, MI, 48109-2117,<br />

United States of America, romeijn@umich.edu<br />

1 - Optimizing the Scenario Positions for Robust Radiation Therapy<br />

Treatment Planning<br />

Albin Fredriksson, KTH Royal Institute of Technology, Department<br />

of mathematics, Royal Institute of Technology, Stockholm, Sw, 100<br />

44, Sweden, albfre@kth.se<br />

Worst case optimization over a set of scenarios is a way to achieve radiation<br />

therapy plans that are robust to uncertainties. However, the multiple scenarios<br />

exacerbate the conflict between target coverage and healthy tissue sparing, and<br />

may lead to unnecessary sacrifices of plan quality even in scenarios with no<br />

conflicts. We therefore optimize the scenario positions while enforcing minimum<br />

requirements, thereby determining scenario positions where the goals can be<br />

simultaneously satisfied.<br />

2 - A Hierarchical Aperture Shape Optimization Method for VMAT<br />

Treatment Planning<br />

Chunhua Men, PhD, Elekta, 13723 Riverport Drive, Suite 100,<br />

Maryland Heights, MO, 63043, United States of America,<br />

chunhua.men@elekta.com, Xiao Han<br />

Volumetric Modulated Arc Therapy (VMAT) is a promising yet complex modern<br />

radiotherapy treatment technique. In this talk, we present a hierarchical aperture<br />

shape VMAT treatment plan optimization method in which an arbitrary<br />

deliverable aperture (e.g., beam-eye-view) is created at each control point, and<br />

each aperture is then modified using a two-step approach based on the “price” of<br />

each beamlet. Clinical tests show the effectiveness and the efficiency of the<br />

proposed method.<br />

3 - Homogeneous Radiation Therapy Treatment Plans for Gamma<br />

Knife Perfexion<br />

Kimia Ghobadi, University of Toronto, 5 King’s College Road,<br />

Tornto, ON, M5S 3G8, Canada, kimia@mie.utoronto.ca,<br />

David Jaffray, Mark Ruschin, Dionne Aleman<br />

In this work the feasibility of fractionated radiation therapy (RT) for Gamma<br />

Knife Perfexion is studied. In RT, the targets are typically large and overlap with<br />

healthy organs, and require homogeneous dose coverage. We use a fast<br />

geometry-based algorithm to select isocentres to provide quality RT treatments.<br />

After isocentres selection, a sector duration optimization is used to find the final<br />

shot shapes. This approach was tested on seven cases and yielded clinically<br />

satisfactory treatments.<br />

4 - A Robust Re-optimization Scheme for Intensity Modulated<br />

Radiation Therapy (IMRT)<br />

Fei Peng, PhD Candidate, University of Michigan, IOE Department,<br />

1205 Beal Ave., Ann Arbor, MI, 48109-2117, United States of<br />

America, feipeng@umich.edu, Marina Epelman, Edwin Romeijn<br />

Errors in patient setup position can bring uncertainty into radiation therapy<br />

treatments. While robust planning before the treatment in some way accounts for<br />

this uncertainty, it is unable to foresee variations in the actual delivered dose. We<br />

propose a robust re-optimization scheme that adjusts the model according to the<br />

delivered dose and the number of fractions remaining, and periodically reoptimizes<br />

the plan. Comparison with the one-shot optimization is presented with<br />

real-patient cases.<br />

INFORMS Phoenix – 2012<br />

113<br />

■ SC26<br />

26- North 221 A- CC<br />

Behavioral Operations<br />

Sponsor: Manufacturing & Service Oper Mgmt<br />

Sponsored Session<br />

Chair: Tava Olsen, Professor, University of Auckland, 12 Grafton Road,<br />

Auckland, 1071, New Zealand, t.olsen@auckland.ac.nz<br />

Co-Chair: Valery Pavlov, University of Auckland, 12 Grafton Road,<br />

Auckland 1071, New Zealand, v.pavlov@auckland.ac.nz<br />

1 - When Does the Devil Make Work? An Empirical Study of the<br />

Impact of Workload on Server’s Performance<br />

Serguei Netessine, Professor, INSEAD, Boulevard de Constance,<br />

Fountainbleau, 77305, France, Serguei.Netessine@insead.edu,<br />

Fangyun Tan<br />

We analyze a large, detailed operational data set from a restaurant chain to shed<br />

new light on how workload. We find that when the overall workload is low, an<br />

increase in the workload leads to higher server performance. However, there is a<br />

saturation point after which any further increase in the workload leads to<br />

degradation of performance.<br />

2 - Product Launches and Buying Frenzies: A Dynamic Perspective<br />

Javad Nasiry, Assistant Professor, Hong Kong University of Science<br />

and Technology, Room 4345, ISOM Dept, HKUST, Clear Water<br />

Bay, Kowloon, Hong Kong, Hong Kong-PRC, nasiry@ust.hk, Pascal<br />

Courty<br />

Buying frenzies in which a firm intentionally undersupplies a product during its<br />

initial launch phase are a common practice within several industries such as<br />

electronics. We develop a dynamic model of buying frenzies based on social<br />

coordination among customers and characterize the conditions under which they<br />

are optimal. We also propose a measure of “consumer desperation” and<br />

demonstrate that buying frenzies can have a signififcant impact on a firm’s profit.<br />

3 - Stuctural Properties of Supply Chain Contracts under<br />

Bounded Rationality<br />

Valery Pavlov, University of Auckland, 12 Grafton Road,<br />

Auckland 1071, New Zealand, v.pavlov@auckland.ac.nz,<br />

Tava Olsen, Elena Katok, Ernan Haruvy<br />

Recent empirical studies on the performance of coordinating contracts made it<br />

clear that the standard theory makes strong predictions that are not always<br />

fulfilled. Our study aims to characterize structural properties of such popular<br />

mechanisms as wholesale pricing, two-part tariffs, and the minimum order<br />

quantity contract using the framework of quantal response equilbirium for<br />

boundedly rational players.<br />

4 - Newsvendor Decisions when Stakes Matter<br />

Mirko Kremer, Pennsylvania State University, State College, PA,<br />

United States of America, muk22@smeal.psu.edu<br />

Research on decision-making in the newsvendor problem has documented<br />

systematic order biases and a persistent inability to learn. We argue that these<br />

behavioral anomalies persist simply because making many small stakes decisions<br />

(the common implementation) allows simple decision heuristics to overpower the<br />

motive to make an optimal decision. In a controlled laboratory experiment, we<br />

find that subjects in fact learn how to place optimal newsvendor orders when<br />

stakes matter.<br />

■ SC27<br />

SC27<br />

27- North 221 B- CC<br />

Operations and Logistics Analytics<br />

Sponsor: Manufacturing & Service Oper Mgmt<br />

Sponsored Session<br />

Chair: Georgia Perakis, Massachusetts Institute of Technology,<br />

Cambridge, MA, United States of America, georgiap@MIT.EDU<br />

1 - Allocating Subsidies as Network Design - Tractable Fairness<br />

Constraints for the System Flow Problem<br />

Gonzalo Romero, Massachusetts Institute of Technology, 100 Main<br />

Street, E62-461, Cambridge, MA, 02142, United States of America,<br />

gromeroy@mit.edu, Retsef Levi, Georgia Perakis<br />

We study the problem faced by a central planner allocating subsidies to competing<br />

firms that provide a commodity, to minimize its market price subject to a budget<br />

constraint and upper bounds on the allocation to each firm. We consider two<br />

types of subsidies, co-payments and technology subsidies, and obtain structural<br />

results and near optimal solutions in various important cases. Additionally, we<br />

characterize a new kind of tractable fairness constraints for the system optimum<br />

flow problem.


SC28<br />

2 - Stochastic Optimization for Resource Allocation with<br />

Random Emergencies<br />

Joline Uichanco, Massachusetts Institute of Technology,<br />

Cambridge, MA, United States of America, uichanco@mit.edu,<br />

Mallik Angalakudati, Siddharth Balwani, Jorge Calzada,<br />

Georgia Perakis, Nicolas Raad<br />

We study the problem of scheduling jobs to resources, assuming a random<br />

number of emergency jobs arrive in the future. We model the problem using<br />

stochastic optimization. We propose decomposition techniques and heuristics, for<br />

which we prove analytic performance guarantees. We apply these to a major US<br />

gas utility company to schedule its services. Using actual data, we show that our<br />

model reduces overtime by 65%. The company is currently piloting a web-based<br />

planning tool using our models.<br />

3 - Maintenance and Flight Scheduling of Low Observable Aircrafts<br />

Retsef Levi, Massachusetts Institute of Technology, 100 Main<br />

Street, Building E62-562, Cambridge, MA, United States of<br />

America, retsef@mit.edu, Vivek Farias, John Kessler,<br />

Thomas Magnanti, Yaron Shaposhnik, Yaron Zarybnisky<br />

We study maintenance scheduling issues that are unique to the Air Force’s lowobservable<br />

aircraft. We classify this problem as a modified restless multi-armed<br />

bandit problem, which allows for multiple types of actions (different maintenance<br />

actions). Using an LP relaxation, we are able to develop index policies that allow<br />

us to decide the timing and type of maintenance to perform on which aircraft, as<br />

well as select which planes should be flown for operations each day.<br />

4 - Integrated Sales and Operations Strategies for Differentiated<br />

Fresh Products<br />

Zhengliang Xue, IBM Research, 1101 Kitchawan Rd., Route 134,<br />

Yorktown, NY, 10598, United States of America,<br />

zxue@us.ibm.com, Markus Ettl, David Yao<br />

We study the coordination of pricing and inventory strategies contingent on<br />

product freshness. A retailer sells both fresh and frozen products where the<br />

fresher provides a higher quality but perishes quickly. Customers are segmented<br />

as high-end and low-end, and high-end customers are more sensitive to<br />

freshness. Customers might upgrade or downgrade their purchase if a stock-out<br />

takes place. We analyze the joint pricing and inventory decisions to maximize the<br />

expect profit under uncertain demand.<br />

■ SC28<br />

28- North 221 C- CC<br />

Empirical Research in Supply Chains<br />

Sponsor: Manufacturing & Service Oper Mgmt<br />

Sponsored Session<br />

Chair: Vishal Gaur, Professor, Cornell University, Johnson School,<br />

Ithaca, NY, 14853, United States of America, vg77@cornell.edu<br />

1 - Deriving Supply Chain Metrics from Financial Statements<br />

Robert Bray, Assistant Professor, Kellogg/Northwestern,<br />

311 Sheridan Ave., Palo Alto, CA, 94306, United States of<br />

America, robertlbray@gmail.com, Haim Mendelson<br />

We develop an empirical supply chain model that enables empiricists to derive<br />

operational metrics from “demand signal processing” how demand information<br />

flows through supply chains and perform corresponding counterfactuals. The<br />

metrics illuminate previously-obscure supply chain aspects, and the<br />

counterfactuals permit related “what if” studies. We demonstrate our<br />

methodology with six studies and firm-level Compustat data.<br />

2 - Managing Global Sourcing: Inventory Performance<br />

Karan Girotra, INSEAD, Boulevard de Constance, Fontainebleau,<br />

France, Karan.GIROTRA@insead.edu, Nitish Jain,<br />

Serguei Netessine<br />

The shift towards sourcing products from global suppliers has been a key<br />

economic trend over the last three decades. This study provides the first rigorous<br />

firm-level empirical evidence, using over half a million sea shipments from global<br />

suppliers to US firms, on the operational impacts of global sourcing and provides<br />

actionable guidance for managing global sourcing.<br />

3 - When Disruptions Matter: An Exploration of Disruption<br />

Types and Moderators<br />

William Schmidt, Harvard Business School, Wyss House, Boston,<br />

MA, 02163, United States of America, wschmidt@hbs.edu,<br />

Ananth Raman<br />

We research and identify several factors that drive a differential impact of supply<br />

chain disruptions on company value. Our research reveals that the market<br />

distinguishes between disruptions not only based on the characteristics of the<br />

disruption, but also on the characteristics of the company which are under<br />

management’s direct control. Insight on this issue can help managers structure<br />

their operations and target risk mitigation efforts toward those disruptions that<br />

destroy the most value.<br />

INFORMS Phoenix – 2012<br />

114<br />

4 - Does Inventory Turnover Predict Future Stock Returns?<br />

Yasin Alan, Cornell University, Sage Hall, Room 301R, Ithaca, NY,<br />

14850, United States of America, ya47@cornell.edu, Vishal Gaur,<br />

George Gao<br />

We examine the impact of inventory turnover performance of publicly listed U.S.<br />

retailers on their stock returns using the traditional approach in the asset pricing<br />

literature with annual test portfolios. We find that high inventory productivity is a<br />

strong predictor of future stock returns, and investigate potential reasons.<br />

■ SC29<br />

29- North 222 A- CC<br />

Queueing Control<br />

Cluster: Workforce Management<br />

Invited Session<br />

Chair: Eser Kirkizlar, State University of New York - Binghamton,<br />

School of Management, Binghamton, NY, United States of America,<br />

eser@binghamton.edu<br />

1 - Optimal Admission Control Policies for Two Station Tandem<br />

Queues with Loss<br />

Daniel Silva, Georgia Institute of Technology, Atlanta, GA, 30363,<br />

United States of America, dfsi3@gatech.edu, Hayriye Ayhan,<br />

Bo Zhang<br />

We study a system of 2 queues in tandem, the 1st station has a buffer of size one,<br />

the 2nd has an arbitrary buffer. There is a gatekeeper and losses incur when a job<br />

is turned away at the first station or when the second is full upon service<br />

completion at the first. We fully characterize the optimal policy to minimize long<br />

run average cost for systems with small to moderate buffers at the 2nd station.<br />

We also propose an easily implementable heuristic policy that yields near optimal<br />

performance.<br />

2 - Dynamic Control of a Closed Two-stage Queueing Network for<br />

Ship Production with Outfitting<br />

Fang Dong, University of Michigan, Ann Arbor, MI,<br />

United States of America, ppfang@umich.edu, Mark Van Oyen,<br />

Soroush Saghafian, David Singer<br />

As an essential and complex part of ship construction, outfitting represents at<br />

least 50% of ship construction cost and time. Ship block outfitting is most cheaply<br />

done at the steel block fabrication (stage 1), but at increased cost and time, it can<br />

be done at the final ship assembly (stage 2). We develop a closed two-stage<br />

queueing network MDP model with decisions as to where outfitting is performed<br />

to gain insights into optimal scheduling control policies.<br />

3 - Parametric Analysis of Optimal Admission Policies in Tandem<br />

Queueing Networks<br />

William Millhiser, Assistant Professor, Baruch College, City<br />

University of New York, One Bernard Baruch Way, Box B9-240,<br />

New York, NY, 10010, United States of America,<br />

william.millhiser@baruch.cuny.edu<br />

We derive the parametric analysis of optimal admission policies in tandem queues<br />

with or without blocking after service. Our method is event-based dynamic<br />

programming. Such analysis allows insights into how admission policies are<br />

sensitive to price, demand, service rates, and workforce staffing choices; it is<br />

generally applicable to systems where service is delivered in stages and advance<br />

reservations are not taken. We give a counterintuitive result, an open problem,<br />

and a conjecture.<br />

4 - Skill and Capacity Management in Large-scale Marketplaces<br />

Eren Cil, University of Oregon, 1208 University of Oregon,<br />

Eugene, OR, 97403-1208, United States of America,<br />

erencil@uoregon.edu, Gad Allon, Achal Bassamboo<br />

We characterize the optimal skill screening mechanism of a firm moderating a<br />

large-scale service marketplace where the ability of a service provider to cater<br />

customers, who can be of two classes, varies. We show that when the values that<br />

a service provider generates for each customer class are independent, the firm<br />

may need to refuse some of the service providers via its screening mechanism<br />

whereas this is never optimal when these values are perfectly correlated.


■ SC30<br />

30- North 222 B- CC<br />

Risk Mitigation in Supply Chain Management<br />

Sponsor: Manufacturing & Service Oper Mgmt/iFORM<br />

Sponsored Session<br />

Chair: Burak Kazaz, Associate Professor, Syracuse University, Whitman<br />

School of Management, 721 University Ave., Syracuse, NY, 13244,<br />

United States of America, bkazaz@syr.edu<br />

1 - Quick Response Rules for Updating Inventories of Substitutable<br />

Products with Short-Term Forecast Updating<br />

Saurabh Bansal, Assistant Professor, Pennsylvania State University,<br />

405 Business Building, University Park, PA,<br />

United States of America, sub32@psu.edu, James Dyer<br />

This paper presents results for determining optimal inventory levels for a<br />

newsvendor who (i) makes a joint-inventory decision for multiple substitutable<br />

products for the next replenishment period using latest forecasts, and (ii) knows<br />

the forecasts and the corresponding optimal inventory levels for the current<br />

replenishment period. These results are extremely easy to implement when faced<br />

with sudden demand shocks.<br />

2 - Corn or Soybean: Optimal Farm Space Allocation under<br />

Yield and Price<br />

Cerag Pince, cerag.pince@the-klu.org, Onur Boyabatli,<br />

Javad Nasiry<br />

We consider farm space allocation decision between corn and soybean in a multiperiod<br />

setting. In each period the farmer decides the allocation due to yield and<br />

spot price uncertainties given the cross-farming benefit, i.e, the yield is<br />

stochastically larger when a product is not grown in the same farm space for two<br />

consecutive periods. We investigate the impact of yield and price variability for<br />

each product, and the correlation among these uncertainties on the optimal farm<br />

allocation decision.<br />

3 - Wine Futures and Advance Selling under Quality Uncertainty<br />

Tim Noparumpa, Assistant Professor, Providence College,<br />

Providence College School of Business, Koffler Hall, Providence,<br />

RI, United States of America, tnoparum@syr.edu, Burak Kazaz,<br />

Scott Webster<br />

We examine the use of wine futures as a form of operational flexibility to mitigate<br />

quality-rating risk in wine production. As the wine ages in barrels, the firm has to<br />

determine what proportion of its wine should be sold as futures, and what<br />

proportion should be sold in retail. While advance selling enables the firm to<br />

recuperate the investment early and pass on the risk of holding inventory that is<br />

uncertain in value to consumers, it can also lead to smaller returns than retail<br />

revenues.<br />

4 - Agricultural Supply Chain Planning under Yield Uncertainty<br />

Nur Cavdaroglu, Post-doctoral Researcher, Whitman School of<br />

Management Syracuse University, Whitman School of<br />

Management Syracuse Un, Syracuse, NY, 13244, United States of<br />

America, ncavdaro@syr.edu, Burak Kazaz, Scott Webster<br />

We consider the production planning problem in an agricultural supply chain<br />

with a single retailer and multiple farmers. The quality level of the product is<br />

directly proportional with the improvement effort (e.g. fertilization) during the<br />

cultivation phase and the price of the end-product changes accordingly with<br />

farmers’ efforts. We analyze the problem and develop pricing mechanisms that<br />

coordinate the system and induce farmers’ to invest in the same level of effort<br />

with the centralized system.<br />

■ SC31<br />

31- North 222 C- CC<br />

Models of Risk and Uncertainty in Supply Chains<br />

Cluster: Managing Disruptions in Supply Chains<br />

Invited Session<br />

Chair: Ed Pohl, University of Arkansas, Department of Industrial<br />

Engineering, Fayetteville, AR, United States of America,<br />

epohl@uark.edu<br />

1 - A Cargo Prioritization Model for Inland Waterway Disruptions<br />

Jingjing Tong, University of Arkansas, 4207 Bell Engineering<br />

Center, Fayetteville, United States of America, tong@uark.edu,<br />

Heather Nachtmann<br />

For an ongoing project funded by the U.S. Department of Homeland Security, we<br />

are developing a cargo prioritization model that can provide timely knowledge<br />

regarding what barges should be prioritized for offloading when the inland<br />

waterway is closed or reduced due to a disruption. Our presentation focus is the<br />

formulation of a non-linear binary integer cargo prioritization model that<br />

considers terminal capacity, barge draft, cargo value, and commodity type.<br />

INFORMS Phoenix – 2012<br />

115<br />

2 - Impact of Random Yield in Decentralized Supply Chains with<br />

Competing Suppliers<br />

Fei Qin, PhD Candidate, University of Cincinnati, College of<br />

Business, 312 Carl H. Lindner Hall, Cincinnati, OH, 45221, United<br />

States of America, qinfi@mail.uc.edu, Haresh Gurnani, Uday Rao<br />

We investigate supply chain (SC) performance when suppliers have unreliable<br />

service rate, defined as a random proportion of the planned production quantity.<br />

We look at single sourcing as well as dual sourcing, where both suppliers<br />

compete. We check the SC agents’ optimal solutions when the suppliers differ<br />

from one another in terms of their yield distributions, their procurement costs,<br />

and their risk correlation levels.<br />

3 - Securing Global Medical Nuclear Supply Chains through<br />

Economic Cost Recovery and Risk Management<br />

Dong Li, Univerity of Massachusetts-Amherst, 121 Presidents<br />

Drive, Amherst, MA, 01003, United States of America,<br />

dongl@som.umass.edu, Anna Nagurney, Ladimer Nagurney<br />

In this paper, we develop a new generalized network model for the optimization<br />

of the complex operations of medical nuclear supply chains in the case of the<br />

radioisotope molybdenum, with a focus on minimizing the total operational cost,<br />

the total waste cost, and the risk associated with this highly time-sensitive and<br />

perishable, but critical, product used in healthcare diagnostics. A case study for<br />

North America demonstrates how our model and computational framework can<br />

be applied in practice.<br />

■ SC32<br />

32- North 223- CC<br />

Assembly Line Design and Balancing II<br />

Contributed Session<br />

SC32<br />

Chair: Jeonghan Ko, Ajou University and University of Michigan,<br />

Department of Industrial Engineering, Suwon, Korea, Republic of,<br />

jko@ajou.ac.kr<br />

1 - Energy Considerations in a Two Machine Flowshop Scheduling<br />

Problem with Sequence Dependent Setups<br />

Afshin Mansouri, Senior Lecturer in Operations and Supply Chain<br />

Management, Brunel Business School, Brunel University London,<br />

Uxbridge, UB8 3PH, United Kingdom,<br />

Afshin.Mansouri@brunel.ac.uk, Emel Aktas<br />

A two-machine flowshop permutation scheduling problem is addressed to<br />

minimize Cmax and energy consumption as conflicting criteria. We develop a<br />

mathematical formulation and propose a Multi-Objective Genetic Algorithm<br />

(MOGA) to find approximations of the Pareto front. Performance of the MOGA is<br />

compared with Cplex on various problems. The MOGA can support informed<br />

decision making via trade-off analysis between Cmax as a measure of service and<br />

energy consumption as a measure of sustainability.<br />

2 - Mathematical and Heuristic Approaches for Simultaneous<br />

Balancing and Sequencing Problem<br />

Rifat Gurcan Ozdemir, Istanbul Kultur University, Atakoy Campus<br />

D100 Yanyol, Istanbul, Turkey, rg.ozdemir@iku.edu.tr,<br />

Selin Kapcak, Tugce Hanci<br />

Mixed model assembly line balancing and sequencing problems are solved<br />

simultaneously by using a mathematical model and a heuristic algorithm. In<br />

balancing problem, tasks are assigned to the stations for minimizing unbalanced<br />

workload. In sequencing problem, launching sequence of products is determined<br />

for minimizing total amount of uncompleted work. A case problem is solved for<br />

illustrating the performances of the developed mathematical model and the<br />

heuristic algorithm.<br />

3 - Exploring the Efficient Frontier of the Multi-objective General<br />

Assembly Line Balancing Problem<br />

Bryan Pearce, Clemson University, Industrial Engineering,<br />

110 Freeman Hall, Clemson, SC, 29634, United States of America,<br />

bpearce@clemson.edu, Kavit Antani, Kilian Funk, Mary E. Kurz,<br />

Maria Mayorga, Laine Mears, Alireza Madadi<br />

Methods for the general assembly line balancing problem are presented for<br />

environments with mixed-model flow, multi-manned stations, and a variety of<br />

task assignment constraints. Several figures of merit can be considered, with<br />

metaheuristic and heuristic methods to support exploring alternative solutions.


SC33<br />

4 - Lot-streaming in Assembly Shops<br />

Niloy Mukherjee, PhD Candidate, Virginia Polytechnic and State<br />

University, 114 Durham Hall, Blacksburg, VA, 24060,<br />

United States of America, niloym@vt.edu, Subhash C. Sarin<br />

We address a two-stage, multiple-lot assembly shop, lot streaming problem. While<br />

lot streaming reduces the makespan, it also increases handling costs. Given a<br />

sequence in which to process the lots, we develop a polynomial time algorithm to<br />

obtain optimal sublot sizes that minimize a weighted sum of the makespan and<br />

transportation costs. A method for sequencing the lots is also proposed.<br />

5 - Assembly Decomposition for Supply Chain and Subassembly<br />

Planning Considering Component Quality<br />

Jeonghan Ko, Ajou University and University of Michigan,<br />

Department of Industrial Engineering, Suwon, Korea, Republic of,<br />

jko@ajou.ac.kr, Hui Wang<br />

We present a decomposition model to divide the assembly to subassemblies to be<br />

joined in the final assembly process. This new graph-theoretic approach evaluates<br />

the effect of subassembly and supply chain structures on the final product quality.<br />

The evaluation also considers the defect rates of components and assembly tasks<br />

as well as inspection errors. The results suggest that the defect rate of the final<br />

product can be managed better by proper subassembly planning and supplier<br />

selection.<br />

■ SC33<br />

33- North 224 A- CC<br />

Sustainable Operations and Supply<br />

Chain Management<br />

Sponsor: Manufacturing & Service Oper Mgmt/Sustainable<br />

Operations<br />

Sponsored Session<br />

Chair: Tim Kraft, University of Virginia, Darden School of Business,<br />

Charlottesville, VA, 22902, United States of America,<br />

kraftt@darden.virginia.edu<br />

1 - Environmental and Economic Assessment of Remanufacturing<br />

Strategies for Product+Service Firms<br />

Anton Ovchinnikov, Darden School of Business, University of<br />

Virginia, 100 Darden Blvd, Charlottesville, VA, 22903, United<br />

States of America, Ovchinnikova@darden.virginia.edu, Gal Raz,<br />

Vered Blass<br />

This paper provides a data-driven assessment of economic and environmental<br />

aspects of remanufacturing for product+service firms. We present a model,<br />

conduct a behavioral experiment to estimate consumer demand, and based on the<br />

realistic parameter values obtained from an industial partner examine when and<br />

why remanufacturing results in higher profit and lower environmental damage.<br />

2 - Making use of Dual Sourcing to Reduce Carbon Emissions<br />

in Transport<br />

Tarkan Tan, Eindhoven University of Technology, Den Dolech 2,<br />

Pav F-7, Eindhoven, 5612AZ, Netherlands, T.Tan@tue.nl,<br />

Kristel Hoen, Geert-Jan van Houtum, Jan Fransoo<br />

We consider a carbon-aware company that orders several products from suppliers,<br />

which can be fulfilled via a fast or a slow channel. We study a multi-item dualsourcing<br />

problem subject to an emission constraint. We use a single-index order<br />

policy that specifies two order-up-to levels and we find solutions for the multiitem<br />

setting that meet the emission constraint. Making use of actual emission<br />

figures, we elaborate on factors that determine when significant emission<br />

reductions can be achieved.<br />

3 - To Sell and to Provide? The Implications of the Auto<br />

Manufacturer’s Involvement in Car Sharing<br />

Yannis Bellos, Georgia Institute of Technology,<br />

800 West Peachtree St. NW, Atlanta, GA, United States of America,<br />

Ioannis.Bellos@mgt.gatech.edu, Beril Toktay, Mark Ferguson<br />

We study the auto manufacturer’s choice regarding whether to provide mobility<br />

service (e.g., car sharing) in conjunction with the traditional sales channel. We<br />

explicitly model the consumer’s choice between purchasing a vehicle, benefiting<br />

from the mobility service or relying on an outside option (e.g., public<br />

transportation) as well as the vehicle usage decisions. We characterize the benefit<br />

to the manufacturer of providing mobility service and the environmental<br />

implications of this strategy.<br />

4 - The NGO’s Dilemma: How to Influence Firms to Replace a<br />

Potentially Hazardous Substance<br />

Tim Kraft, University of Virginia, Darden School of Business,<br />

Charlottesville, VA, 22902, United States of America,<br />

kraftt@darden.virginia.edu, Yanchong Karen Zheng, Feryal Erhun<br />

In this paper, we analyze an NGO’s decisions when a substance within a product<br />

is identified as potentially hazardous (e.g., BPA). We determine under what<br />

market and regulatory conditions an NGO should target the industry versus a<br />

INFORMS Phoenix – 2012<br />

116<br />

regulatory body in order to influence firms to replace a substance. We consider<br />

the perspectives of both an antagonistic NGO that maintains an arms-length<br />

relationship with firms and a pragmatic NGO that takes into consideration firm<br />

costs when making its decisions.<br />

■ SC34<br />

34- North 224 B - CC<br />

Collaboration and Innovation in Product Development<br />

Contributed Session<br />

Chair: Celestine Aguwa, Visiting Assistant Professor,<br />

Wayne State University, 4815 Fourth Street, Detroit, MI, 48201,<br />

United States of America, celestine.aguwa@wayne.edu<br />

1 - Effect of Bargaining Power and Information Asymmetry on<br />

Product Quality in Outsourcing<br />

Narendra Singh, PhD Candidate, Georgia Institute of Technology,<br />

800 West Peachtree Street NW, Atlanta, GA, 30308, United States<br />

of America, Narendra.Singh@mgt.gatech.edu, Stylianos Kavadias,<br />

Ravi Subramanian<br />

We examine the effect of outsourcing on product quality when the OEM has a<br />

backup option of manufacturing the product herself. We characterize the<br />

situation as a game-theoretic model consisting of sequential decisions made by<br />

the OEM and the contract manufacturer (CM) in two scenarios - the CM offering<br />

the contract to the OEM, and vice-versa. We contrast the results for the two<br />

scenarios in the absence and presence of information asymmetry about cost<br />

structure.<br />

2 - Choice of Equity Partnerships for New Product Development<br />

Niyazi Taneri, Singapore University of Technology and Design,<br />

20 Dover Drive, Singapore, Singapore, niyazitaneri@sutd.edu.sg,<br />

Arnoud De Meyer<br />

We develop two games of equity partnerships for Joint Ventures and Licensing<br />

Agreements. We find that operational constraints have opposing impacts on the<br />

value from each partnership structure and play a role in the choice among the<br />

two alternatives. Analysis of alliance choice data from the pharmaceutical<br />

industry supports our analytical results.<br />

3 - Effect of Correlated Beliefs on the Survival of Collaborative R&D<br />

Projects<br />

Xiang He, University of Cambridge, Emmanuel College,<br />

Saint Andrews Street, Cambridge, CB2 3AP, United Kingdom,<br />

xh232@cam.ac.uk, Nektarios Oraiopoulos<br />

Owing to the remarkable uncertainty in drug R&D, biotech and pharmaceutical<br />

firms often engage in exploratory R&D within multiple alliances. Case evidence<br />

suggests that contracts are often writ with neither party having an accurate<br />

estimate of the value of the drug candidate. Accordingly, we study the<br />

effectiveness of R&D collaboration on the project level when both firms have<br />

imperfect but correlated beliefs about the quality of the drug candidate.<br />

4 - The Impact of Exploration and Exploitation on Innovation<br />

Success and Innovation Failure<br />

Jennifer Bailey, Georgia Institute of Technology,<br />

800 W. Peachtree Road, NW, Atlanta, GA, United States of<br />

America, Jennifer.Bailey@mgt.gatech.edu, Manpreet Hora<br />

We investigate the impact of exploration and exploitation learning activities on<br />

the innovation process. Specifically, our two-pronged approach examines how<br />

these activities can be effectively harnessed to first, achieve innovation success<br />

and second, to mitigate innovation failure. We utilize patent data in the biotech<br />

industry to test our hypotheses.<br />

5 - Effect of Ratings Modification on a Fuzzy-based Modular<br />

Architecture for Medical Device Design<br />

Celestine Aguwa, Visiting Assistant Professor, Wayne State<br />

University, 4815 Fourth Street, Detroit, MI, 48201, United States<br />

of America, celestine.aguwa@wayne.edu, Leslie Monplaisir,<br />

Prasanth Sylajakumari<br />

This research is to determine the effect of customer ratings on the optimal<br />

number of modules for medical device design. To address this issue, a typical<br />

glucometer is used as proof of concept to demonstrate the methodology and<br />

analyze the impact of changing the customer ratings on the optimal number of<br />

modules and minimum deviation. The implication is to generate scholarly work<br />

and to reduce the number of potential failure points in medical devices by<br />

determining the optimal number of modules.


■ SC35<br />

35- North 225 A- CC<br />

Ticket Pricing and Demand Estimation<br />

Sponsor: Revenue Management & Pricing<br />

Sponsored Session<br />

Chair: Ozge Sahin, Johns Hopkins University, 100 International Dr.,<br />

Baltimore, MD, 21202, United States of America, ozge.sahin@jhu.edu<br />

1 - Should Event Organizers Prevent Resale of Tickets?<br />

Yao Cui, PhD Candidate, University of Michigan, 701 Tappan<br />

Street, Ann Arbor, MI, 48109, United States of America,<br />

cuiyao@umich.edu, Izak Duenyas, Ozge Sahin<br />

We are interested in whether preventing consumer resale of tickets benefits<br />

capacity providers for sporting and entertainment events. Consumers’ purchasing<br />

decisions take into account their inter-temporal valuations as well as their<br />

potential opportunity to resell the tickets. We compare the revenues from fixed<br />

pricing, dynamic pricing and pricing with options, and consider how the capacity<br />

provider’s revenues change with respect to the transaction cost of resale under<br />

each pricing strategy.<br />

2 - Semi-parametric Estimation of Ticket Purchases at a Theater<br />

Necati Tereyagoglu, Assistant Professor, Georgia Institute of<br />

Technology, College of Management, Atlanta, GA,<br />

United States of America, necati.tereyagoglu@scheller.gatech.edu,<br />

Senthil Veeraraghavan<br />

We develop a semi-parametric competing proportional hazard framework that<br />

models the dynamic effects of an organization’s show and time related pricing<br />

decisions on the customer’s propensity to purchase a ticket for a variety of shows<br />

during a specified timeframe. We test our model on ticket sales and seat pricing<br />

data for a season of 21 concerts from a leading performing arts organization. We<br />

suggest a discounting policy using these estimates.<br />

3 - Revenue Management of Consumer Options for Tournaments<br />

Caner Gocmen, Columbia Business School, 3022 Broadway,<br />

Uris Hall, 4V, New York, NY, 10027, United States of America,<br />

fgocmen13@gsb.columbia.edu, Robert Phillips, Guillermo Gallego,<br />

Santiago Balseiro<br />

We analyze tournament options where the event manager sells team-specific<br />

options for a tournament final, such as the Super Bowl, before the finalists are<br />

determined. These options guarantee a final game ticket to the bearer if her team<br />

advances to the finals. We develop an approach by which an event manager can<br />

determine the revenue maximizing prices and amounts of tickets and options to<br />

sell for a tournament final. We show that offering options can increase expected<br />

revenue and social welfare.<br />

4 - Endogeneity and Price Sensitivity in Customized Pricing<br />

A. Serdar Simsek, PhD Candidate, Columbia Business School,<br />

3022 Broadway, Uris Hall, 4L, New York, NY, 10027,<br />

United States of America, asimsek13@gsb.columbia.edu,<br />

Robert Phillips, Garrett Van Ryzin<br />

Endogeneity occurs in customized pricing when a seller uses unrecorded<br />

customer characteristics correlated with price-sensitivity in setting the price.<br />

Endogeneity can lead traditional regression approaches to under-estimate price<br />

elasticity. We use two sources of data from auto loan pricing: one from an on-line<br />

lender and one from an indirect lender to test for endogeneity. We present our<br />

results as well as recommendations for how to detect and control for endogeneity<br />

in the estimation process.<br />

■ SC36<br />

36- North 225 B- CC<br />

Revenue Management and Pricing Applications<br />

Sponsor: Revenue Management & Pricing<br />

Sponsored Session<br />

Chair: Ahmet Kuyumcu, President, Prorize LLC, 3399 Peachtree Rd NE,<br />

STE 400, Atlanta, GA, 30326, United States of America,<br />

akuyumcu@prorize.com<br />

1 - Revenue Optimization for Rental Industry<br />

Hossam Zaki, Vice President, Zilliant, Austin, TX,<br />

United States of America, hossam.zaki@zilliant.com<br />

This presentation will provide insights and comparisons between the revenue<br />

management (RM) problem for the One-Way Truck Rental industry and other<br />

traditional RM problems (e.g. equipment rental, car rental, airline and air cargo).<br />

We will also describe the main components of a typical RM system and several<br />

design and deployment options.<br />

INFORMS Phoenix – 2012<br />

117<br />

2 - Optimal Pricing for Student Housing<br />

Jian Wang, Vice President, The Rainmaker Group,<br />

4550 North Point Parkway, Suite 400, Alpharetta, GA, 30022,<br />

United States of America, jwang@letitrain.com<br />

The application of revenue management to conventional multi-family housing<br />

has been successful, but it is new to student housing. In this presentation, we<br />

describe some unique characteristics of student housing, and point out the<br />

drawbacks of prevalent pricing methods. We then propose an optimal pricing<br />

model, and illustrate the application to a real case.<br />

3 - Luxury Yacht Rentals – How to Forecast Demand and<br />

Optimize Prices?<br />

Pelin Pekgun, Assistant Professor, University of South Carolina,<br />

Moore School of Business, 1705 College Street, Columbia, SC,<br />

29208, United States of America, Pelin.Pekgun@moore.sc.edu,<br />

Ronald Menich<br />

Luxury yacht rentals is a niche market with a unique business model that<br />

presents rich revenue opportunities but also makes it vulnerable in a challenging<br />

economy. Traditional forecasting approaches do not work due to data sparsity and<br />

low volume of transactions, while pricing becomes difficult with hard-to-identify<br />

price elasticity from customers that already pay high prices. We present a<br />

forecasting and optimization framework that can address the unique challenges in<br />

this environment.<br />

4 - Market Share Modeling in Revenue Management<br />

Ahmet Kuyumcu, President, Prorize LLC, 3399 Peachtree Rd. NE,<br />

Ste. 400, Atlanta, GA, 30326, United States of America,<br />

akuyumcu@prorize.com, Utku Yildirim<br />

Market share modeling could be effectively used when demand and price data for<br />

majority of the competing products is available. This presentation briefly reviews<br />

market share modeling and provides successful real-world applications.<br />

■ SC37<br />

SC37<br />

37- North 226 A- CC<br />

Location Models<br />

Sponsor: Location Analysis<br />

Sponsored Session<br />

Chair: Oded Berman, Professor, University of Toronto, 105 St. George<br />

Street, Toronto, ON, M5S 3E6, Canada, Berman@Rotman.Utoronto.Ca<br />

1 - Linearization Techniques for the p-Median Problem with<br />

Unreliable Facilities<br />

Serigne Gueye, Assistant Professor, University of Avignon, 339<br />

chemin des Meinajariès, Agroparc BP 91228, Avignon, 84911,<br />

France, sgueye@zlc.edu.es, Mozart Menezes<br />

The p-Median problem with unreliable facilities consists in locating m unreliable<br />

facilities to n customers in such a way to minimize the expected cost of serving<br />

the customers. Each facility has a disruption probability, independent to the site<br />

location and to other facility. The problem is expressed as a bilinear program for<br />

which some linearization techniques are applied. Numerical tests are then<br />

performed.<br />

2 - The Downside Risk-averse Center on a Network<br />

Jiamin Wang, Long Island University, Long Island, NY,<br />

United States of America, Jiamin.Wang@liu.edu<br />

We consider finding a location that minimizes the maximum expected weighted<br />

distance to the nodes of a network with random demand weights. This problem is<br />

similar to the classical center problem except VAR, a downside risk-averse<br />

measure, is adopted as a constraint. We derive a set of dominant points and<br />

develop algorithms for demand weights of discrete and continuous probability<br />

distributions. This study provides a better understanding of the impact of risk<br />

attitude on location decisions.<br />

3 - Minimax Regret Covering Location on a Network<br />

under Uncertainty<br />

Oleksandr Shlakhter, University of Toronto, Joseph L. Rotman<br />

School of Management, 105 St. George Street, Toronto, ON, M5S<br />

3E6, Canada, alex.shlakhter@Rotman.Utoronto.Ca, Dmitry Krass,<br />

Oded Berman<br />

We consider p-cover problem on a network with uncertain weights of nodes. For<br />

each node only interval estimate of its weight is known. The problem is to find<br />

the “minimax regret” covering location, i.e. to minimize worst case loss in<br />

objective function because a location decision is made without knowing the<br />

actual weights at nodes. We present the algorithm for this problem on a general<br />

network. We also consider two special cases, when the solution algorithm is<br />

polynomial.


SC38<br />

4 - Resource Allocation for a New Product Introduction:<br />

Joint Facility Location and Marketing Strategies<br />

Vahideh Sadat Abedi, PhD Candidate, University of Toronto,<br />

105 St. George Street, Toronto, ON, M5S 3E6, Canada,<br />

VahidehSadat.Abedi07@Rotman.Utoronto.Ca, Oded Berman,<br />

Dmitry Krass<br />

We analyze the problem of joint design of the network of retail facilities and<br />

marketing strategies of a firm introducing an innovative product or service to a<br />

network of markets. After introducing a framework for the joint study of these<br />

decisions, we study the effect of different types of marketing media and their<br />

substitutive behaviour. We also investigate allocation of resources of the firm<br />

between different types of media and opening facilities.<br />

■ SC38<br />

38- North 226 B- CC<br />

Service Operations and Retailing<br />

Sponsor: Service Science<br />

Sponsored Session<br />

Chair: Olga Perdikaki, Assistant Professor, Mays Business School at<br />

Texas A&M University, 320 Wehner Building, College Station, TX,<br />

77843-4217, United States of America, operdikaki@mays.tamu.edu<br />

1 - Timining of Service Investments under Competition and<br />

Demand Uncertainty<br />

Olga Perdikaki, Assistant Professor, Mays Business School at Texas<br />

A&M University, 320 Wehner Building, College Station, TX,<br />

77843-4217, United States of America,<br />

operdikaki@mays.tamu.edu, Jayashankar M. Swaminathan,<br />

Dimitris Kostamis<br />

We study how competition and demand uncertainty affect firms’ timing of service<br />

level decisions relative to demand realization. We model a symmetric duopoly in<br />

which firms compete on price and service levels and analytically characterize the<br />

Nash equilibrium in the timing of service level decisions.<br />

2 - Retail Execution and Store Associate Incentive Design<br />

Nicole DeHoratius, Zaragoza Logistics Center, Edifico Náyade 5,<br />

C/ Bari 55-Plaza, Zaragoza, Spain, NDeHoratius@zlc.edu.es,<br />

Saravanan Kesavan, Adam Mersereau<br />

We determine the extent to which a change in the design of store associate<br />

incentives at several pilot stores of a major retail chain drive store associate effort<br />

allocation and consequently store performance. Our results yield insights useful to<br />

a retail chain seeking to maximize long-term profitability rather than short-term<br />

sales when designing store associate incentive plans.<br />

3 - Inventory Record Inaccuracy: Operational Causes and<br />

Labor Effects<br />

Howard Hao-Chun Chuang, PhD Candidate, Mays Business School<br />

at Texas A&M University, College Station, TX, 77843-4217,<br />

United States of America, hchuang@mays.tamu.edu, Rogelio Oliva<br />

Inventory record inaccuracy (IRI) can be attributed to shrinkage, misplacement,<br />

and transaction errors. We develop a system dynamics model that captures the<br />

physics of in-store operations while integrating multiple sources of error. By<br />

performing Monte-Carlo simulation, we confirm the conjecture that labor-related<br />

errors are roor causes of IRI. We then empirically test the impact of store labor<br />

and environments on IRI using Bayesian shrinkage estimation and panel data<br />

modeling.<br />

4 - Optimal Dynamic Return Management of Fixed Inventories<br />

Mehmet Sekip Altug, Assistant Professor, George Washington<br />

University, 2201 G. Street, NW, Washington, DC,<br />

United States of America, maltug@gwu.edu<br />

We consider a retailer that sells a fixed amount of inventory over a finite horizon.<br />

We assume that return policy is a decision variable which can be changed<br />

dynamically at every period. While flexible return policies generate more<br />

demand, it also induces more returns. We characterize the optimal dynamic<br />

return policies based on two costs of return scenarios. We find out how these<br />

policies change with inventory and time. We extend our model to multiple<br />

competing retailers.<br />

INFORMS Phoenix – 2012<br />

118<br />

■ SC39<br />

39- North 226 C- CC<br />

Service Science & Innovations with Analytics<br />

Sponsor: Service Science<br />

Sponsored Session<br />

Chair: Haluk Demirkan, Professor, Arizona State University,<br />

P.O. Box 874606, Tempe, AZ, 85287, United States of America,<br />

haluk.demirkan@asu.edu<br />

1 - Transitioning to a Service-oriented Business Model:<br />

A Technology Roadmapping Approach<br />

Robert Harmon, Professor of Marketing & Technology<br />

Management, Portland State University, School of Business,<br />

Portland, OR, 97207, United States of America,<br />

corevalue@comcast.net, Bill Hefley, Haluk Demirkan<br />

For technology firms, the evolution from manufacturing to service-dominant<br />

business models as a primary driver of innovation has become an important<br />

trend. This research reviews the literature on the key dimensions, frameworks,<br />

and organizational considerations for the service transition process. It utilizes a<br />

technology roadmapping approach to illustrate the issues and strategy dimensions<br />

faced by a technology manufacturer as it navigates the service transition process.<br />

2 - Quality of Service Modeling for Internet Service Providers<br />

Seyedreza Mousavi, Arizona State University, BA 319, WPC School<br />

of Business, Arizona State University, Tempe, AZ, 85287,<br />

United States of America, smousav4@exchange.asu.edu<br />

According to the literature, there are three main contributors to quality of service<br />

of internet service providers: traffic and network engineering, network<br />

architecture, and interconnection. The current study attempts to develop a model<br />

in which market and quality factors are linked together. A panel of experts rated<br />

the strength of each relationship in the model. The results revealed how the<br />

contributors to the QoS significantly impact the ISP’s profit.<br />

3 - Effects of Electronic Payment Services on Consumer Behavior<br />

in Electronic Retailing: A Research Prop<br />

Irfan Kanat, Arizona State University, W.P. Carey School of<br />

Business, Tempe AZ 85287, United State of America<br />

ikanat@asu.edu, Ajay Vinze, Paul Steinbart<br />

e-payment services advanced rapidly in the recent years. Major e-retailers like ebay<br />

are now players in the market, traditional financial institutions are trying to<br />

defend their positions with new products. Each service offers a different set of<br />

features suited for different transactions. The effects of the features sets on<br />

consumer behavior has not been investigated in the literature. We present a<br />

review of the literature and propose a quasi experimental research design to<br />

address this gap.<br />

■ SC40<br />

40- North 227 A- CC<br />

Wind Energy, Optimal Location and<br />

Effective Utilization<br />

Sponsor: Energy, Natural Res & the Environment/Energy<br />

Sponsored Session<br />

Chair: Golbon Zakeri, University of Auckland, 70 Symonds Street,<br />

Auckland, New Zealand, g.zakeri@auckland.ac.nz<br />

1 - Mitigating Real Time Price Uncertainty Induced by Wind Power<br />

through Stochastic Unit Commitment<br />

Anthony Papavasiliou, University of California at Berkeley, 4141<br />

Etcheverry Hall, IEOR Department, Berkeley, CA, 94720-1777,<br />

United States of America, anthony.papavasiliou@gmail.com,<br />

Yi He, Alva Svoboda<br />

Wind power supply uncertainty introduces significant uncertainties in day-ahead<br />

trading due to its impact on real-time electricity prices. In particular, in the day<br />

ahead market utilities face the challenge of self-commitment, self-scheduling and<br />

cycling decisions on slow units. We present a stochastic unit commitment model<br />

and solution methodology for addressing these challenges and demonstrate<br />

savings relative to current practice which is based on deterministic models.


2 - The Effects of Stochastic Market Clearing on the Cost of Wind<br />

Integration: A Case of New Zealand Electricity Market<br />

Javad Khazaei, Princeton University, Department of ORFE,<br />

Princeton, NJ, United States of America, jkhazaei@princeton.edu,<br />

Geoff Pritchard, Golbon Zakeri<br />

Implementing a stochastic electricity market clearing, as a suggested alternative to<br />

conventional clearing mechanisms, can impose some extra cost on the market.<br />

Therefore, it is essential to estimate the efficiency gain resulting from<br />

implementing a stochastic market clearing mechanism. We describe the result of<br />

an empirical study to quantify value of a stochastic clearing mechanism for the<br />

New Zealand electricity market. We extend our analysis for possible larger wind<br />

integration in the future.<br />

3 - Modeling the Economics of Variable Generation Resources<br />

James Merrick, Electric Power Research Institute (EPRI), 3420<br />

Hillview Avenue, Palo Alto, CA, 94304, United States of America,<br />

jmerrick@epri.com, Geoffrey Blanford<br />

The US-REGEN model is a general equilibrium model of the United States<br />

economy, with a detailed regional representation of the power sector. The power<br />

sector component is formulated as a quadratic programming problem. This talk<br />

will provide an overview of the optimization formulation, focusing on how the<br />

spatial and temporal distributions of variable generation resources are<br />

represented. The formulation of the sub-problem to choose and weight<br />

representative hours will be additionally presented.<br />

4 - Capacity Expansion in an Electrical System with Intermittent<br />

and Weather-dependent Generation<br />

Phil Bishop, Senior Economist, Electricity Authority, P.O. Box<br />

10041, Wellington, 6143, New Zealand, phil.bishop@ea.govt.nz,<br />

Bruce Smith<br />

The electricity system in NZ is dominated by generating plant based on highly<br />

variable hydrological resources yet conditions currently favor investment in<br />

geothermal and intermittent plant. Capacity expansion in this setting entails<br />

challenges for the efficient and reliable operation of the system and imposes costs<br />

beyond those incurred by the generation investor. A capacity expansion model<br />

with a detailed treatment of firming requirements is described and simulation<br />

results are presented.<br />

■ SC41<br />

41- North 227 B- CC<br />

Renewable Energy Issues<br />

Contributed Session<br />

Chair: Paulo Correia, Professor, Unicamp, Energy Department,<br />

Campinas, Brazil, pcorreia@fem.unicamp.br<br />

1 - Costs and Environmental Attributes of Bulk Energy<br />

Transportation Options for Renewable Energy<br />

Elisabeth Gilmore, University of Maryland, 2101 Van Munching<br />

Hall, College Park, MD, United States of America,<br />

gilmore@umd.edu, Andrew Blohm<br />

We develop a multi-attribute decision model to evaluate options for long distance<br />

transport of bulk energy from renewable sources, focusing on the cost and<br />

environmental trade-offs. We find that the preferred option depends on distance,<br />

the amount of energy to be transported, and the existing infrastructure and<br />

markets. We apply the model to an ocean thermal energy conversion (OTEC)<br />

installation where we include moving the energy as ammonia, either as an energy<br />

carrier or as fertilizer.<br />

2 - Competition, Welfare and Green Energy<br />

Talat Genc, University of Guelph, Department of Econ,<br />

Guelph, N1G2W1, Canada, tgenc@uoguelph.ca<br />

We estimate the behavior in hourly wholesale electricity auctions and address<br />

some policy questions relevant to intermittent technologies and air pollution in a<br />

dynamic game-theoretic analysis. We examine the Ontario wholesale electricity<br />

market and find that our competition model has a high predictive power. MAE<br />

for our price estimations is much lower than the one for ISO estimations. We also<br />

calculate the welfare loss generated in the market.<br />

3 - Wind Farm Layout Optimization Considering Multiple Objectives<br />

Jose Espiritu, Assistant Professor, The University of Texas at El<br />

Paso, 500 West University Avenue, El Paso, TX, 79902, United<br />

States of America, jfespiritu@utep.edu, Carlos Ituarte-Villarreal,<br />

Nicolas Lopez, Heidi Taboada<br />

This work presents a new multiple objective evolutionary algorithm to obtain<br />

optimal placement of wind turbines in a wind farm, the objective functions<br />

considered are the maximization of power output, the minimization of wind farm<br />

cost and the maximization of system reliability. In the present work, we solve<br />

three well known problems. The final solution to this multiple objective problem<br />

is presented as a set of Pareto solutions.<br />

INFORMS Phoenix – 2012<br />

119<br />

4 - Studying Various Optimal Control Problems in Biodiesel<br />

Production in a Batch Reactor under Uncertainty<br />

Pahola Benavides, Graduate Student, University of Ilinois at<br />

Chicago, Industrial Engineering, Chicago, IL, 60607,<br />

United States of America, ptatibg@uic.edu, Urmila Diwekar<br />

Optimal control problems encountered in biodiesel production are formulated<br />

using various performance indices like maximum concentration, minimum time,<br />

and maximum profit. The problems involve determining optimal temperature<br />

profile so as to maximize these performance indices. This paper presents these<br />

three formulations with and without variability and uncertainty in feed<br />

composition.<br />

5 - Trading Energy from Wind Plants with a Portfolio Approach<br />

Paulo Correia, Professor, Unicamp, Energy Department, Campinas,<br />

Brazil, pcorreia@fem.unicamp.br, Laura Gunn<br />

The growing environmental impacts associated to the generation of electric<br />

energy highlights the need to expand the use of renewable energy sources. These<br />

sources use natural resources whose availability depends on climate behavior<br />

which normally entails a certain intrinsic risk. Therefore, the evaluation of an<br />

alternative energy source project always involves a commitment between the<br />

expected benefit and the risk incurred, which can be conveniently dealt with a<br />

Markovitz benefit-risk model.<br />

■ SC42<br />

42- North 227 C- CC<br />

Routing and Travel Time Prediction<br />

Contributed Session<br />

SC42<br />

Chair: Behzad Aghdashi, Research Assistant, North Carolina State<br />

University, 2510-203 Avent Ferry Rd, Raleigh, NC,<br />

United States of America, saghdas@ncsu.edu<br />

1 - Improved Tour Determination for the Dynamic Traveling<br />

Salesman Problem<br />

Taesu Cheong, Assistant Professor, National University of<br />

Singapore, 1 Engineering Drive 2, Singapore, 117576, Singapore,<br />

isects@nus.edu.sg, Alan Erera, Chelsea (Chip) White<br />

After each stop of a multi-stop trip, we assume that the vehicle chooses the next<br />

stop to visit, based on current traffic conditions. Travel time along each arc in the<br />

network is modeled as a random variable, and we assume that network<br />

congestion dynamics can be described by a stationary Markov chain. We propose<br />

an efficient algorithm for determining the next stop to visit in a multi-stop tour,<br />

using action elimination procedures and a rolling forecast horizon.<br />

2 - A Case Study for Time-dependent Routing Planning with<br />

Time Windows<br />

Qian An, PhD Candidate, University of Southern California,<br />

Los Angeles, CA, 90007, United States of America, qan@usc.edu,<br />

James Moore, Ugur Demiryurek, Cyrus Shahabi<br />

In this paper we study the importance of time-dependent route planning as<br />

opposed to static planning. A time-dependent network dataset of the entire Los<br />

Angeles County highways and arterial streets is used. It includes 6300 traffic<br />

sensor data with update rate of every 1 minute covering approximately 3000<br />

miles. With extensive experiments we show that time-dependent planning could<br />

save 9% as compared to static planning in uniform time window cases, and 20%<br />

in random time window cases.<br />

3 - A Hierarchical Agent-based Simulation for Traveler Behaviors<br />

Yiheng Feng, University of Arizona, 1127 E. James E. Rogers Way,<br />

P.O. Box 210020, Tucson, AZ, 85705, China,<br />

yihengfeng@email.arizona.edu, Hui Xi, Sojung Kim,<br />

Young-Jun Son, Larry Head<br />

A hierarchical agent-based framework is proposed to model the travelers’<br />

behaviors with route choice on the upper level and tactical driving on the lower<br />

level. The route choice level considers learning from previous experiences,<br />

heterogeneity of different travelers, and incomplete network information, while<br />

the tactical driving level concerns car-following and lane changing behaviors.<br />

Results from the proposed models are shown to reach the same user equilibrium<br />

solutions as in the literature.<br />

4 - Path and Multi-step Ahead Freeway Travel Time Prediction<br />

Wenxin Qiao, University of Maryland-College Park, 1173 Glenn<br />

Martin Hall, College Park, MD, 20742, United States of America,<br />

wxqiao@umd.edu, Ali Haghani<br />

This research utilized multiple data sources to predict freeway travel times<br />

through an integrated model based on large historical traffic and weather<br />

information dataset, along with real time traffic information. This model is<br />

proposed to perform path and multi-step ahead travel time prediction. Numerical<br />

experiments are conducted and comparison results of different models’<br />

performances are presented as well as sensitivity analysis on the efficient size of<br />

the historical dataset.


SC43<br />

5 - Scenario Generation in Freeway Reliability Analysis<br />

Behzad Aghdashi, Research Assistant, North Carolina State<br />

University, 2510-203 Avent Ferry Rd, Raleigh, NC,<br />

United States of America, saghdas@ncsu.edu<br />

Scenario Generation is primary step in evaluating freeway’s travel time reliability.<br />

In this research different mathematical modeling challenges are discussed. The<br />

main focus of this research is to minimize the error and bias imposed by modeling<br />

incidents and weather events.<br />

■ SC43<br />

43- North 228 A- CC<br />

Joint Session RAS/CPMS: Panel Discussion:<br />

Analytics and Intermodal<br />

Sponsor: Railway Applications & CPMS, The Practice Section<br />

Sponsored Session<br />

Chair: Bruce Patty, Vice President, Veritec Solutions, 824 Miramar<br />

Terrace, Belmont, CA, 94002, United States of America,<br />

bpatty@veritecsolutions.com<br />

1 - Roundtable on Analytics and Intermodal<br />

Moderator: Bruce Patty, Vice President, Veritec Solutions, 824<br />

Miramar Terrace, Belmont, CA, 94002, United States of America,<br />

bpatty@veritecsolutions.com, Panelists: Gino Phillips, Craig Littzen,<br />

Vernon Prevatt<br />

This roundtable will take place during two sessions. During this first session, there<br />

will be three panelists from the Intermodal industry (Gino Phillips from APL,<br />

Craig Littzen from Swift, and Vernon Prevatt from CSX) who will share their<br />

thoughts about current and potential applications of analytics to the intermodal<br />

industry. After their opening presentations, there will be an opportunity for the<br />

audience to ask questions and participate in an open discussion.<br />

■ SC44<br />

44- North 228 B- CC<br />

Contracts in Supply Chain<br />

Contributed Session<br />

Chair: Arnab Bisi, Associate Professor of Operations Management,<br />

Indian Institute of Management Calcutta, Joka, Kolkata, 700104, India,<br />

abisi@iimcal.ac.in<br />

1 - Optimization of Supplier and Customer Strategies under<br />

Options Contract and Unknown Pricing/Demand<br />

Matan Shnaiderman, Bar-Ilan University, Ramat-Gan, 52900,<br />

Israel, shnidem@biu.ac.il, Avi Ceder<br />

This work develops optimal strategies of a supplier and customers when using<br />

options contract. One supplier sells goods for two customers. The supplier uses<br />

option contracts, for extending profits, such that the customers have the<br />

possibility to purchase options in advance and being the first to receive the<br />

production. The stochastic demands at the customers’ sites are continuously<br />

distributed. We show that customers who receive high profits, are interested to<br />

buy the options and exercise them.<br />

2 - Operations and Marketing Equilibrium Strategies under<br />

Wholesale Price and Revenue Sharing Contracts<br />

Fouad El Ouardighi, Professor, ESSEC Business School, Av. B.<br />

Hirsch, Cergy Pontoise cedex, 95021, France, elouardighi@essec.fr,<br />

Dieter Grass, Steffen Jorgensen, Gary Erickson<br />

The paper studies the relative merits of two specific contracts, the wholesale price<br />

and the revenue sharing contract in a dynamic vertical channel with one<br />

manufacturer and one retailer. We consider decisions that develop from Nash<br />

equilibria. Two different strategies are available to the players, i.e., open-loop and<br />

feedback Nash equilibrium strategies. We compare how these different strategies<br />

affect the players’ decisions and payoffs under wholesale price and revenue<br />

sharing contracts.<br />

3 - The Impact of Supplier Innovation on Contract Efficiency<br />

Xiaolu Zuo, PhD Student, City University of Hong Kong,<br />

Tat Chee Avenue, Kowloon, Hong Kong, Hong Kong-PRC,<br />

zuoxiaolu29@gmail.com, John Liu<br />

Consider in a one supplier-one retailer supply chain setting, the supplier<br />

experiences process improvement, reflected by the production cost reduction,<br />

which follows a discrete dynamic way. We analyze the impact of supplier<br />

innovation on the efficiency of supply chain contract and give an explanation for<br />

the incentive of supplier innovation.<br />

INFORMS Phoenix – 2012<br />

120<br />

4 - Wholesale-price Contracts with Postponed and Fixed<br />

Retail Price<br />

Arnab Bisi, Associate Professor of Operations Management, Indian<br />

Institute of Management Calcutta, Joka, Kolkata, 700104, India,<br />

abisi@iimcal.ac.in, Yanyi Xu<br />

We study wholesale-price contracts with retail price-postponement in a supply<br />

chain consisting of one manufacturer and one retailer. For additive and<br />

multiplicative demand models, we establish sufficient conditions for the<br />

unimodality of profit functions and derive the unique optimal solutions. We also<br />

extend existing results on the fixed retail price case and a revenue management<br />

problem.<br />

■ SC45<br />

45- North 229 A- CC<br />

Joint Session MI/HAS: Operations Research in<br />

Patient Safety and Care Quality<br />

Sponsor: Minority Issues & Health Applications Society<br />

Sponsored Session<br />

Chair: Laila Cure, Assistant Professor, Western Michigan University,<br />

4601 Campus Dr., Kalamazoo, MI, 49008-5336, United States of<br />

America, laila.cure@wmich.edu<br />

1 - A Multiple-drawer Medication Layout Problem in Automated<br />

Dispensing Cabinets<br />

Jennifer Pazour, Assistant Professor, University of Central Florida,<br />

4000 Central Florida Blvd, Orlando, FL, 32816, United States of<br />

America, Jennifer.Pazour@ucf.edu, Russell Meller<br />

We investigate the problem of locating medications in automated dispensing<br />

cabinets to minimize human selection errors. We formulate the multiple-drawer<br />

medication layout problem as a quadratic assignment problem. As a way to<br />

evaluate various medication layouts, we develop a similarity rating for medication<br />

pairs. To solve industry-sized problem instances, we develop a heuristic approach.<br />

2 - A Decision Support Model for the Location of Hand Sanitizer<br />

Dispensers in Hospitals Units<br />

Laila Cure, Assistant Professor, Western Michigan University,<br />

4601 Campus Dr., Kalamazoo, MI, 49008-5336,<br />

United States of America, laila.cure@wmich.edu<br />

Noncompliance with hand hygiene guidelines is a cause of infection in hospitals.<br />

To improve compliance, hand sanitizer dispensers should be placed in convenient<br />

locations, but fire safety regulations constrain their number and distribution. We<br />

develop a model to incorporate guidelines, regulation, and hospital characteristics<br />

into the dispenser installation decision. The proposed model can help in<br />

evaluating the current locations of dispensers and in determining the best possible<br />

configuration.<br />

3 - A Hub Infrastructure to Reduce Infusion Pump Medication<br />

Errors in Hospitals<br />

Kenneth Musselman, Strategic Collaboration Director, Regenstrief<br />

Center for Healthcare Engineering, Purdue University, Mann Hall,<br />

Suite 225, 203 Martin Jischke Drive, West Lafayette, IN, 47907,<br />

United States of America, kmusselm@purdue.edu<br />

Reliable, timely and low cost data collection is necessary to achieve a significant<br />

reduction in hospital medication errors. The Infusion Pump Informatics (IPI)<br />

System, which was developed using a hub infrastructure, allows infusion pump<br />

data to be readily accessible, meaningful and actionable. Participating hospitals are<br />

now forming virtual communities that exchange information, share analysis<br />

results, trigger research, and collaborate on ways to improve patient safety.<br />

4 - Prediction, Non-clinical Factors and Intervention in<br />

Unnecessary Hospital Readmissions<br />

Brandon Pope, Purdue University, 315 N. Grant Street,<br />

West Lafayette, IN, United States of America, popeb@purdue.edu<br />

Unnecessary readmissions waste $17 B per year in U.S. hospitals on Medicare<br />

patients alone. In this presentation we focus on calibrating predictive models<br />

using nearly 400,000 discharges over a 3.5 year span from a network of 11 U.S.<br />

hospitals. We also examine the relative importance of non-clinical factors in<br />

readmission rates. Motivated by financial reform, we model the discharge<br />

intervention problem, highlighting the possibility of unintuitive optimal policies,<br />

and opportunities for research.


■ SC46<br />

46- North 229 B- CC<br />

Organizational and Industry Renewal (III): Leadership,<br />

Team Management, and Organizational Learning<br />

Sponsor: Organization Science<br />

Sponsored Session<br />

Chair: Andreas Schwab, Associate Professor, Iowa State University,<br />

3315 Gerdin, Ames, IA, 50011, United States of America,<br />

aschwab@iastate.edu<br />

1 - Schematic Inertia: A Dynamic and Complexity Pespective on<br />

Sared Cognition<br />

Benjamin Herndon, Assistant Professor, Georgia Institute of<br />

Technology, 800 W. Peachtree St., NW, Atlanta, GA, 30308, United<br />

States of America, benjamin.herndon@mgt.gatech.edu, Kyle Lewis<br />

This paper extends theories of socially shared cognition by forwarding a<br />

framework to explain how – over time – teams are affected by dynamic and<br />

residual schema and dimensions of shared cognition. We articulate these<br />

dimensions and consider how they form, accrue and decay as team tasks and<br />

boundaries change over time. Finally, we posit relationships between these<br />

dimensions and a team’s ability to realize performance synergy or dissonance on<br />

the task at hand.<br />

2 - Exploring the Role of Culture in Psychological Safety and<br />

Team Learning<br />

Mary Zellmer-Bruhn, Associate Professor, University of Minnesota,<br />

321 19th Ave., S, Minneapolis, 55455, United States of America,<br />

zellm002@umn.edu<br />

Psychological safety is vital to internal and external team learning. Given<br />

differences in behavioral expectations across cultures, evidence that work-related<br />

constructs may carry different meaning across cultures, and increases in globally<br />

distributed work, examining psychological safety in different cultural settings is a<br />

valuable avenue for research. This paper presents an exploratory framework for<br />

the role of culture and language differences in team psychological safety.<br />

3 - An Exploration of Inter-Organizational Heterogeneity in<br />

Organizational Goal Setting<br />

Cynthia Penaflor, Research Assistant, Brigham Young University,<br />

2112 Margalene Way, Austin, TX, 78728, United States of<br />

America, cynthiapenaflor@gmail.com, Peter Madsen<br />

Limited availability of data on organizational goals has necessitated the<br />

imputation of organizational goals in empirical tests of the behavioral theory of<br />

the firm; but this approach cannot account for inter-organizational heterogeneity<br />

in goal setting. Our project plans to overcome this challenge by analyzing newlyavailable<br />

data from all companies that have been members of the S&P 500 index<br />

from 2006-2011. We test how closely imputed goals approach self-reported<br />

organizational goals.<br />

4 - Shared Leadership: The Impact of the Occupy Movement on<br />

Decision Making in Organizations<br />

Adina Lav, Doctoral Student, George Washington University,<br />

2480 16th Street, NW #445, Washington, DC, 20009,<br />

United States of America, adinalav@gwmail.gwu.edu<br />

Social and political movements around the globe witnessed over the past year are<br />

great examples of the changes taking place in how people learn from each other<br />

and express their leadership at the societal level. This oral presentation describes<br />

the Occupy movement and its organic development of consensus building and<br />

shared leadership and calls for organizations to broaden their perspectives of<br />

decision making by understanding new ways in which leadership and consensusbuilding<br />

takes place.<br />

■ SC47<br />

47- North 230- CC<br />

Travel Time Estimation and Applications<br />

Sponsor: Transportation Science & Logistics/ Intelligent<br />

Transportation Systems (ITS)<br />

Sponsored Session<br />

Chair: Xuesong Zhou, University of Utah, 110 Central Campus Dr,<br />

MCE 2000, Salt Lake City, UT, 84112, United States of America,<br />

zhou@eng.utah.edu<br />

1 - Predicting Corridor-level Travel Time Distributions Based on<br />

Stochastic Flow and Capacity Variations<br />

Hao Lei, Phd Student, University of Utah, 110 Central Campus Dr,<br />

MCE 2000, Salt Lake City, UT, 84112, United States of America,<br />

hao.lei@utah.edu, Xuesong Zhou<br />

This research aims to establish a point-queue based end-to-end travel time<br />

INFORMS Phoenix – 2012<br />

121<br />

prediction method on a corridor with multiple merges and diverges. A set of<br />

analytical equations is developed to calculate the number of queued vehicles<br />

ahead of the probe vehicle and further capture many important factors affecting<br />

end-to-end travel times.<br />

2 - On the Link Travel Time Imputation Methods<br />

Lei Zhu, Graduate Research Assisant, University of Arizona, 1209<br />

E 2nd street, RM 324J, Tucson, AZ, 85721,<br />

leizhu@email.arizona.edu, Yi-Chang Chiu<br />

Link travel time imputation is important for shortest path algorithms under a<br />

certain circumstance. Based on traffic flow conservation law and the average flow<br />

theorem, the missing travel time can be estimated by flow of adjacent upstream<br />

and downstream road segments. In this research, the missing link travel times are<br />

categorized into several conditions and the proposed imputation methods have<br />

been shown to deal with each condition effectively.<br />

3 - ParkPGH: Pittsburgh’s Predictive Parking App<br />

Tayo Fabusuyi, Lead Strategist, Numeritics, 5907 Penn Ave., Suite<br />

313, Pittsburgh, PA, 15206, United States of America,<br />

Tayo.Fabusuyi@numeritics.com, Robert Hampshire,<br />

Katsunobu Sasanuma<br />

ParkPGH is a smart parking solution that provides information on the availability<br />

of parking spaces within Pittsburgh’s downtown. The application uses an event<br />

calendar, historical data, multiple regression model and a Bayesian updating<br />

process in making both long and short term predictions about parking availability.<br />

Parking information is delivered through channels that include websites, SMS<br />

text, voice, iPhone app and a mobile version of the website that is optimized for<br />

other smartphones.<br />

4 - Quantification of the Benefits of Real-time Information for<br />

Individual Travelers<br />

Dongyoon Song, NEXTRANS Center, USDOT Region V Regional<br />

UTC, School of Civil Engineering, Purdue University,<br />

West Lafayette, IN, 47906, United States of America,<br />

song50@purdue.edu, Srinivas Peeta<br />

This study seeks to quantify the benefits of real-time travel information in terms<br />

of both conventional travel time savings as well as psychological effects for<br />

individual travelers. Revealed preference (RP) data from an experiment with a<br />

driving simulator and stated preference (SP) data from a survey will be utilized in<br />

behavioral analysis to estimate the value of the real-time information.<br />

■ SC48<br />

SC48<br />

48- North 231 A- CC<br />

Traveling Salesman Problem with Time Windows<br />

Sponsor: Transportation Science & Logistics/ Freight<br />

Transportation & Logistics<br />

Sponsored Session<br />

Chair: Amelia Regan, University of California, Irvine, CA,<br />

United States of America, aregan@uci.edu<br />

1 - Hybrid Parallel Metaheurustics for the Traveling Salesman<br />

Problem with Time Windows<br />

Amelia Regan, University of California, Irvine, CA, United States<br />

of America, aregan@uci.edu, Dmitri Arkhipov<br />

Our work examines a novel way to parallelize the TSPTW problem.<br />

2 - The Probabilistic Travelling Salesman Problem with Time<br />

Windows<br />

Stacy Voccia, University of Iowa, Iowa City, IA, United States of<br />

America, stacy-voccia@uiowa.edu, Barrett W. Thomas,<br />

Ann M. Campbell<br />

We introduce the Probabilistic Traveling Salesman Problem with Time Windows<br />

(PTSPTW), where in addition to stochastic customer presence, each customer has<br />

an associated time window during which deliveries must be made. We present a<br />

recourse model and a Variable Neighborhood Search (VNS) algorithm to solve<br />

problem instances. Using computational experiments, we demonstrate the value<br />

of incorporating stochasticity into the model.<br />

3 - A Branch-and-Price Approach for Vehicle Routing with Soft<br />

Time Windows and Stochastic Travel Times<br />

Duygu Tas, TU/e Eindhoven University of Technology, School of<br />

Industrial Engineering, P.O. Box 513, Eindhoven, 5600 MB,<br />

Netherlands, D.Tas@tue.nl, Michel Gendreau, Tom van Woensel,<br />

Nico Dellaert, Ton de Kok<br />

We study a vehicle routing problem with soft time windows and stochastic travel<br />

times. In our problem setting, we have for each node, except the depot, a known<br />

demand, a fixed service duration and a soft time window. Our objective is to<br />

minimize the sum of transportation costs and service costs. We apply a column<br />

generation procedure to solve our model. To generate an integer solution, we<br />

embed our column generation procedure within a branch-and-price method.


SC49<br />

4 - A Divide-and-conquer Analysis of Very Large Asymmetric<br />

Vehicle Routing Problems<br />

Dauwe Vercamer, Ghent University, Ghent, 9000, Belgium,<br />

Dauwe.Vercamer@ugent.be, Birger Raa, Dirk Van den Poel<br />

When working with extremely large datasets in real-life VRPs, solution<br />

neighborhoods must be kept simple in order to obtain reasonable process times.<br />

By dividing the set into smaller samples, more elaborate neighborhoods can be<br />

explored or the total process time can be reduced. However, this also limits the<br />

optimization. Our research investigates the impact of using these smaller samples<br />

on the solution quality and provides approaches for overcoming the downsides of<br />

the division.<br />

5 - A Multi-terminal Truckload Pickup and Delivery Problem with<br />

Time Windows in a Dynamic Context<br />

Hossein Zolfagharinia, Wilfrid Laurier University, 1207-125<br />

Lincoln Road, Waterloo, ON, N2J 2N9, Canada, zolf1380@wlu.ca,<br />

Michael Haughton<br />

We study a dynamic full truckload pickup and delivery problem with time<br />

windows. In this work, we explicitly address the role of terminals in designing a<br />

dispatching rule in which driving hours regulations are taken into account. We<br />

show how the model can be mathematically formulated and efficiently solved.<br />

■ SC49<br />

49- North 231 B- CC<br />

Joint Session TSL/SPPSN: From Emergency<br />

Preparedness to Debris Cleanup<br />

Sponsor: Transportation Science & Logistics & Public Programs,<br />

Service and Needs<br />

Sponsored Session<br />

Chair: Changhyun Kwon, Assistant Profesor, University at Buffalo,<br />

SUNY, 400 Bell Hall, Buffalo, NY, 14260, United States of America,<br />

chkwon@buffalo.edu<br />

1 - Innovative Cycle Canceling Algorithm for Routing of Evacuees<br />

in Networks with Multiple Threat Zones<br />

Neema Nassir, Graduate Research Assistant, University of Arizona,<br />

Department of Civil Engineering and Engineering Mechanics,<br />

1209 E. Second Street, Tucson, AZ, 85721-0072, United States of<br />

America, neeman@email.arizona.edu, Mark Hickman,<br />

Yi-Chang Chiu, Hong Zheng<br />

An exact algorithm is developed and tested for finding the optimal routing of<br />

traffic flows, to evacuate a network with several threat zones, where the threat<br />

level may depend on the exposure or risk in each zone. A network<br />

transformation is proposed that facilitates detecting flow-augmenting paths, in<br />

which the cycles with the highest negative costs are quickly identified.<br />

2 - Dual-Toll Pricing and Drivers’ Preferences in Hazardous<br />

Materials Transportation Regulation<br />

Changhyun Kwon, Assistant Profesor, University at Buffalo, SUNY,<br />

400 Bell Hall, Buffalo, NY, 14260, United States of America,<br />

chkwon@buffalo.edu, Tolou Esfandeh, Masoumeh Taslimi,<br />

Rajan Batta<br />

A dual-toll setting policy is used as an effective and flexible regulation tool to<br />

encourage the carriers to route shipments on low risk paths. The proposed model<br />

not only aims to minimize the total risk on the network but also to consider the<br />

drivers’ preferences and priorities in route selection based on toll prices and travel<br />

time. Risk measurement model entails the risk in terms of overall accident<br />

probability and the consequences of the accident occurrence.<br />

3 - Robust Shelter Location in Geographic and<br />

Building Environments<br />

Elise Miller-Hooks, Professor, University of Maryland, 1173 Glenn<br />

L. Martin Hall, College Park, MD, 20742, United States of America,<br />

elisemh@umd.edu, Shabtai Isaac, Lei Feng, Reza Faturechi<br />

A bilevel, integer stochastic program is presented for the robust shelter location<br />

problem in geographic and building environments. At the upper level, the<br />

optimal location and size of shelters is chosen to support evacuation given an<br />

event requiring building occupants or individuals in the region to seek egress or<br />

protective covering. Individuals choose egress routes to these safe locations in the<br />

lower level to minimize disutility (travel time, exposure, geometric<br />

considerations, ...).<br />

4 - Post-disaster Debris Recycling and Disposal<br />

Alvaro Lorca, Georgia Institute of Technology, 765 Ferst Dr NW,<br />

Atlanta, GA, United States of America, alvarolorca@gatech.edu,<br />

Pinar Keskinocak, Ozlem Ergun<br />

The large volumes of debris generated by disasters can generate severe long term<br />

financial and environmental problems to the affected communities if not handled<br />

appropriately. We study the impact of strategic decisions in the collection and<br />

INFORMS Phoenix – 2012<br />

122<br />

disposal phases of post-disaster debris management such as recycling, collecting<br />

debris separately and incinerating debris, on the tradeoff between financial costs<br />

and environmental issues.<br />

■ SC50<br />

50- North 231 C- CC<br />

Raytheon (USA) and Brazilian Navy Defense<br />

Applications<br />

Sponsor: Military Applications<br />

Sponsored Session<br />

Chair: George Blaha, Senior Principal Systems Engineer, Raytheon<br />

Integrated Defense Systems, 2461 S. Clark St. #1100, Arlington, VA,<br />

22202, United States of America, gblaha@raytheon.com<br />

1 - Data Association using Fuzzy Knowledge<br />

Cleber Oliveira, DSc, Brazilian Navy, Ilha de Mocangue s/n,<br />

Niteroi, 24040-300, Brazil, cleber.almeida@casop.mar.mil.br<br />

This paper presents a maritime tactical picture, which was assembled by the<br />

association of the reports from surface targets provided by multiple sensors of a<br />

Brazilian vessel. The decision-making process conjugates the gating technique and<br />

the conceptual structure of decisions in a fuzzy environment to solve the data<br />

association problem considering four dimensions.<br />

2 - Leveraging Mission Analysis and Modeling to Investigate<br />

Conceptual CG VOI Location Decision Support<br />

David Procter, Raytheon Integrated Defense Systems,<br />

225 Presidential Way, Woburn, MA, United States of America,<br />

david_procter@raytheon.com, Fred Mott<br />

This paper presents the approach and results of a joint Raytheon - U.S. Coast<br />

Guard mission analysis and experiment to evaluate mission analysis-derived<br />

decision support concepts supporting USCG missions. The objective was to<br />

identify and investigate, via mission analysis and modeling, the potential of<br />

candidate decision support aids and CONOPS to enhance maritime security.<br />

Raytheon’s Mission Profiling (Patented) approach was applied to a conceptual<br />

vessel of interest (VOI) location application.<br />

3 - Sensor Scheduling for Space Event Identification<br />

and Characterization<br />

George Blaha, Senior Principal Systems Engineer, Raytheon<br />

Integrated Defense Systems, 2461 S. Clark St. #1100, Arlington,<br />

VA, 22202, United States of America, gblaha@raytheon.com,<br />

Christopher Cox, Michael Schmidt<br />

Timely identification and characterization of space events (e.g. breakups,<br />

maneuvers, conjunctions, dockings) requires effective scheduling of Space<br />

Surveillance Network (SSN) sensors. We present techniques for modeling event<br />

characterization peformance and quantifying the need for improved data<br />

collection. Combined with needs-based scheduling, these techniques may be used<br />

to develop effective observation schedules. Application to the current and<br />

planned SSN architecture is considered.<br />

■ SC51<br />

51- North 232 A- CC<br />

Joint Session MAS/SPPSN: Defense Operations and<br />

Homeland Security I<br />

Sponsor: Military Applications & Public Programs, Service and<br />

Needs<br />

Sponsored Session<br />

Chair: Anna Doro-on, Sr. Consultant/Project Engineer, Water, Tunnel &<br />

Infrastructure Concepts, Inc., 120 S. Euclid Avenue, Pasadena, CA,<br />

91101, United States of America, anna@annaforhomelandsecurity.com<br />

1 - Military Support for Homeland Security: Iranian WMD<br />

Anna Doro-on, Sr. Consultant/Project Engineer, Water, Tunnel &<br />

Infrastructure Concepts, Inc., 120 S. Euclid Avenue, Pasadena, CA,<br />

91101, United States of America,<br />

anna@annaforhomelandsecurity.com, Martin Hershkowitz<br />

Iranian weapons of mass destruction (WMD) is a threat against United States, that<br />

has created the government to initiate both military and civil support. This paper<br />

demonstrates risk assessment based on cumulative prospect theory, analyzes the<br />

alternatives for effectiveness of military operations in the event of attacks for risk<br />

acceptability.


2 - Optimization Models for Improvements to Civil Infrastructure<br />

Systems Subject to Natural Hazards<br />

Brian Piper, North Carolina State University, 2500 Stinson Drive,<br />

Raleigh, NC, United States of America, bepiper@ncsu.edu,<br />

Ranji Ranjithan<br />

We present optimization models to improve the resilience of a civil infrastructure<br />

system (CIS) subjected to natural hazards. The engineering improvements<br />

considered reduce the risk to the CIS by either limiting consequences or reducing<br />

their associated probabilities. The uncertainties inherent to future natural hazards<br />

are represented by hazard scenarios. The models are applied to realistic data from<br />

a coastal community to demonstrate the value of a system-wide approach to the<br />

CIS improvements.<br />

3 - Dividing a Territory with Obstacles<br />

Raghuveer Devulapalli, Research Assistant, University of<br />

MInnesota, 310 8th St SE #205, MInneapolis, MN, 55414, India,<br />

devul002@umn.edu, John Carlsson<br />

We consider the problem of dividing a territory into sub-regions so as to balance<br />

workloads of $n$ fixed facilities over that territory. We assume that the territory<br />

is a simply connected polygon containing a set of simply connected obstacles. We<br />

give a fast analytic center cutting plane method that divides the territory into $n$<br />

compact, connected sub-regions, each of which contains a facility, such that the<br />

workloads in each sub-region are balanced.<br />

4 - Optimal Selection of Countermeasures in IT Security Planning<br />

Tadeusz Sawik, Professor, AGH University of Science &<br />

Technology, Department OR & IT, Al.Mickiewicza 30, Krakow,<br />

30059, Poland, ghsawik@cyf-kr.edu.pl<br />

A mixed integer programming and conditional value-at-risk are applied for<br />

selection of countermeasure portfolio in IT security planning to prevent or<br />

mitigate cyber-threats. Given a set of potential threats and a set of available<br />

countermeasures, the selection of countermeasures is based on their effectiveness<br />

of blocking different threats, implementation costs and probability of potential<br />

attack scenarios.<br />

■ SC52<br />

52- North 232 B- CC<br />

Renewable Energy Integration Strategies<br />

Sponsor: Energy, Natural Res & the Environment/Energy<br />

Sponsored Session<br />

Chair: Seyed Madaeni, PhD Candidate, The Ohio State University,<br />

210 Baker Systems Engineering Building, 1971 Neil Avenue,<br />

Columbus, OH, 43210, United States of America, madaeni.1@osu.edu<br />

1 - Optimal Location of Wind Power Capacity: A Point-estimate<br />

Solution Approach<br />

Salvador Pineda, Technical University of Denmark, DTU Electrical<br />

Engineering, Elektrovej, Kongens Lyngby, 2800, Denmark,<br />

spmo@elektro.dtu.dk, Juan Miguel Morales<br />

We present a tool for a generating company to optimally decide on the<br />

investment in new wind power capacity. The tool is formulated as a stochastic<br />

mathematical program with equilibrium constraints, which is hard to solve. We<br />

propose a point-estimate solution approach that effectively captures the<br />

information embedded in the probability distributions of the uncertain<br />

parameters, while remarkably trimming down the computational burden of the<br />

model.<br />

2 - A Nash Equilibrium Method to Control Plug-in Electric Vehicle<br />

Charging with Wind Integration<br />

Xiaomin Xi, The Ohio State University, 1971 Neil Avenue,<br />

Columbus, OH, 43210, United States of America, xi.12@osu.edu,<br />

Ramteen Sioshansi, Vincenzo Marano<br />

We apply a decentralized method using Nash Equilibrium to control plug-in<br />

electric vehicle (PEV) charging so as to reduce the negative effect of wind<br />

uncertainty. A economic dispatch model and a cost minimization problem are<br />

solved iteratively, in which SO sends scenario-based prices to a load aggregator<br />

(LA) that represents PEV owners, and LA submits bids by minimizing expected<br />

charging cost plus a penalty term. Convergence is assured under certain rules but<br />

is not necessarily social optimum.<br />

3 - Quantifying Variability and Uncertainty Metrics for Wind and<br />

Solar Power<br />

Patrick Sullivan, National renewable Energy Laboratory, Golden,<br />

CO, 80401, United States of America, Patrick.Sullivan@nrel.gov<br />

Using the ReEDS capacity-expansion model as a backdrop, we present statistical<br />

methods for quantifying variability and uncertainty of wind and solar power<br />

across an interconnected grid. Algorithms that estimate capacity value, operating<br />

reserve requirements, and curtailment levels describe the impact of resource<br />

variability on the electric sector and inform model investment decisions.<br />

INFORMS Phoenix – 2012<br />

123<br />

4 - Capacity Value of Photovoltaic Power<br />

Seyed Madaeni, PhD Candidate, The Ohio State University,<br />

210 Baker Systems Engineering Building, 1971 Neil Avenue,<br />

Columbus, OH, 43210, United States of America,<br />

madaeni.1@osu.edu, Paul Denholm, Ramteen Sioshansi<br />

In this study we focus on capacity value of Photovoltaic (PV) power and compare<br />

techniques that can be used for this purpose. These techniques consist of either<br />

reliability and statistical methods used to estimate the probability of a system<br />

outage event or simpler approximation techniques. We further investigate the<br />

effect of including subhourly data in our analysis.<br />

■ SC53<br />

SC53<br />

53- North 232 C- CC<br />

Real Options in the Energy Sector<br />

Sponsor: Energy, Natural Res & the Environment/Energy<br />

Sponsored Session<br />

Chair: Afzal Siddiqui, University College London, Gower Street,<br />

London, United Kingdom, afzal.siddiqui@ucl.ac.uk<br />

1 - Economics of High-temperature Reactors for Industrial<br />

Cogeneration: A Utility’s Perspective<br />

Reinhard Madlener, Professor of Energy Economics and<br />

Management, RWTH Aachen University, Mathieustrasse, Aachen,<br />

52074, Germany, RMadlener@eonerc.rwth-aachen.de,<br />

Jona Hampe<br />

We study the economics of high-temperature reactors (HTR) for nuclear<br />

cogeneration, based on a business model developed from a utility’s perspective.<br />

For the economic evaluation, we perform a discounted cash flow (DCF) analysis,<br />

followed by a real options analysis (ROA) used to determine the value of the<br />

utility’s flexibility to react to market changes. We investigate both the option to<br />

delay the investment and the option to switch power plant operation from<br />

cogeneration to power-only mode.<br />

2 - Switching Options: Empirical Evidence from the<br />

Electricity Industry<br />

Stein-Erik Fleten, Professor, Norwegian University of Science and<br />

Technology, Industrial Economics and Technology Mgmt.,<br />

Alfred Getz v 3, Trondheim, NO-7491, Norway,<br />

stein-erik.fleten@iot.ntnu.no, Carl Ullrich, Erik Haugom<br />

We examine empirically the real options to shutdown, startup, and abandon<br />

peaking power plants. The unique dataset details information for 1,337 individual<br />

plants for the period 2001–2009. Reduced form regressions provide evidence of<br />

real options effects for shutdown and abandonment decisions. Moreover,<br />

uncertainty about the outcome of ongoing deregulation in retail electricity<br />

markets significantly decreases the likelihood of shutting down operating plants.<br />

3 - Sequential Investment, Capacity Sizing, Dividing Flexibility<br />

Ryuta Takashima, Chiba Institute of Technology, Chiba, Japan,<br />

takashima@sun.it-chiba.ac.jp, Kimitoshi Sato, Yuta Naito<br />

We consider the problem of a typical investor who has discretion over not only<br />

the timing, but also the sizing of a new plant in sequential manner. We contrast<br />

the sequential investment strategies for different stage numbers in order to the<br />

value of flexibility. Additionally, we analyze the sequential investment for a case<br />

in which there exists a fixed cost in the investment one. The optimal stage<br />

numbers of sequential investment are obtained for various fixed coasts.<br />

4 - Investment in Alternative Energy Technologies under Physical<br />

and Policy Uncertainty<br />

Afzal Siddiqui, University College London, Gower Street, London,<br />

United Kingdom, afzal.siddiqui@ucl.ac.uk, Ryuta Takashima<br />

Policymakers have often backed alternative energy technologies, e.g., nuclear<br />

power, due to their relatively low operating costs and emissions. However, they<br />

have also been quick to respond to public perceptions about the safety of such<br />

plants by suspending construction or even decommissioning existing facilities. We<br />

address public concerns about physical plant risks along with stochastic market<br />

prices for energy in modelling investment and decommissioning of alternative<br />

energy technologies.


SC54<br />

■ SC54<br />

54- Regency Ballroom A- Hyatt<br />

Memorial Sloan-Kettering Cancer Center - 2012<br />

INFORMS Prize Winning Organization<br />

Cluster: 2012 INFORMS Prize<br />

Invited Session<br />

Chair: Michael Gorman, University of Dayton, Dayton, OH, United<br />

States of America, michael.gorman@udayton.edu<br />

1 - Memorial Sloan-Kettering Cancer Center - 2012 INFORMS Prize<br />

Winning Organization<br />

Sasha Bartashnik, Memorial Sloan-Kettering Cancer Center,<br />

405 Lexington Avenue, 3rd Floor, New York, NY, 10174,<br />

United States of America, bartasha@mskcc.org<br />

Memorial Sloan-Kettering Cancer Center (MSK) is the oldest and one of the<br />

largest cancer hospitals in the world - over 25,000 patients come to MSK for<br />

treatment every year. The changing health care landscape presents a unique<br />

challenge for hospital administrators in providing better quality care at lower cost.<br />

Increasing demand against tighter resource constraints reinforces the institution’s<br />

focus on their mission: better outcomes for patients. These challenges, as well as<br />

MSK’s high volume of longitudinal care, create an opportunity to develop a<br />

fundamental platform for using quantitative methods to gain operational,<br />

strategic, and clinical insights. In 2006 MSK established the department of<br />

Strategic Planning and Innovation (STPI) based on the idea that better patient<br />

care means finding financially sustainable, patient-centered solutions. By working<br />

at the intersection of leadership, clinical staff, and physicians, STPI integrates<br />

OR/MS concepts within the hospital. Quantitative analysis, industrial engineering<br />

and design research teams collaborate to find innovative approaches to some of<br />

the hospital’s most difficult challenges, including improving process flow,<br />

modeling resource utilization, and introducing a volume forecasting system. MSK<br />

continues to push the frontiers of cancer care as it partners with IBM to use<br />

powerful machine learning technology to develop a comprehensive evidencebased<br />

medical intelligence engine.<br />

■ SC55<br />

55- Regency Ballroom B - Hyatt<br />

Healthcare Applications<br />

Cluster: Operations Research in Emerging Economies<br />

Invited Session<br />

Chair: Janny Leung, Professor, Chinese University of Hong Kong,<br />

System Eng. and Engineering Management, Shatin, New Territories,<br />

Hong Kong - PRC, jleung@se.cuhk.edu.hk<br />

1 - A Tracking Study in Medical Wards using RFID<br />

Ziye Zhou, The Chinese University of Hong Kong, Dept. of Syst.<br />

Eng. & Eng. Mgmt., Shatin, NT, Hong Kong, Hong Kong-PRC,<br />

zhouzy@se.cuhk.edu.hk, Chun-Hung Cheng, Dorbin Tobun Ng<br />

A large-scale tracking pilot study was conducted in two 40-bed Medical wards in<br />

a Hong Kong hospital since Fall 2011 for 6 months. This work is to illustrate how<br />

the tracking data were analyzed to support data-driven activity analysis & personto-person<br />

contact tracing in the hospital ward environment.<br />

2 - Evaluating Impacts of Staffing Policies on Patient Flows in an<br />

Emergency Department using Simulation<br />

Yong Hong Kuo, The Chinese University of Hong Kong, SEEM<br />

Dept,Chinese Uni. of Hong Kong, Shatin, New Territories,<br />

Hong Kong, NT, Hong Kong-PRC, yhkuo@se.cuhk.edu.hk,<br />

Benedetta Lupia, Omar Rado, Colin Graham, Janny Leung<br />

We studied impacts of staffing policies on patient flows in an Emergency<br />

Department in Hong Kong. We built a simulation model of the Emergency<br />

Department, which captures all relevant treatment processes, complicated arrival<br />

rates and adjustable staff deployment. To tackle a challenge of data<br />

incompleteness, we estimated required parameters in our model with the help of<br />

meta-heuristics. We will also present some insights and suggestions for<br />

operational improvements by using our model.<br />

INFORMS Phoenix – 2012<br />

124<br />

■ SC56<br />

56- Curtis A- Hyatt<br />

Entrepreneurship and Innovation I<br />

Sponsor: Technology Management<br />

Sponsored Session<br />

Chair: Sinan Erzurumlu, Assistant Professor, Babson College,<br />

231 Forest Park, Babson Park, MA, 02457, United States of America,<br />

serzurumlu@babson.edu<br />

1 - Optimal Bargaining Power in an Entrepreneurial Market<br />

Process<br />

Mohammad Keyhani, York University, 4700 Keele St., Schulich<br />

School of Business, Toronto, On, M3J 1P3, Canada,<br />

mkeyhani08@schulich.yorku.ca, Moren Lévesque<br />

We investigate the role of bargaining power in the economic returns to agents<br />

engaged in repeated cooperative games over time representing an entrepreneurial<br />

market process in line with the Austrian economics of entrepreneurship. We find<br />

that as expected, players with greater bargaining power accrue greater returns<br />

under various conditions, but under certain conditions closer to the Kirznerian<br />

school of thought the pattern is more complicated and not necessarily monotonic.<br />

2 - Are Innovative Companies also More Interactive? Evidence<br />

from Company Websites<br />

John Angelis, Rochester Institute of Technology, 105 Lomb<br />

Memorial Drive, Rochester, NY, United States of America,<br />

jangelis@saunders.rit.edu, Rajendran SriramachandraMurthy<br />

For innovative firms, interaction with customers may lead to improved<br />

innovation, but also may lower innovation efficiency. We assess firms ranked by<br />

innovation premium in Forbes Magazine’s list of Top 100 Innovative Small-Cap<br />

Firms. Each website is evaluated on interaction opportunities for customers based<br />

on such areas as educational opportunities, co-creation options, and social media<br />

opportunities. We find strong industry-related impacts on innovation types<br />

selected by firms.<br />

3 - Growth of New Business Ventures through Innovation<br />

Replicability<br />

Juliana Hsuan, Professor, Copenhagen Business School,<br />

Department of Operations Management, Solbjerg Plads 3,<br />

Frederiksberg, DK-2000, Denmark, jh.om@cbs.dk,<br />

Moren Lévesque<br />

We propose a formal model of firm growth through replication that considers the<br />

extent of the investment to adapt routines as replication unfolds and the portion<br />

of this investment that goes toward innovation in the routines. Two growth<br />

policies for new business ventures emerge: bull-imitation and bear-innovation.<br />

4 - Operations Design to Enhance ARPA-E Funding for<br />

Transformational Clean Technology Start-ups<br />

Sinan Erzurumlu, Assistant Professor, Babson College, 231 Forest<br />

Park, Babson Park, MA, 02457, United States of America,<br />

serzurumlu@babson.edu, Jane Davies, Nitin Joglekar<br />

This paper analyzes the role of operations design in securing funding for highly<br />

risky projects. We use data from 36 transformational innovative clean technology<br />

projects to examine to what extent the operational decisions can mitigate risk and<br />

enhance firm valuation during clean technology start-up. We find that operations<br />

design for risk reduction induces more funding, but design for market<br />

competitiveness shows significant negative correlation to level of funding.<br />

■ SC57<br />

57- Curtis B- Hyatt<br />

Queueing Systems<br />

Contributed Session<br />

Chair: Philippe Chevalier, Professor, UCLouvain, core,<br />

34 Voie du Roman Pays, Louvain-la-Neuve, 1348, Belgium,<br />

philippe.chevalier@uclouvain.be<br />

1 - Interpolation Approximations for Many Single Queues in Series<br />

Kan Wu, Assistant Professor, Nanyang Technological University,<br />

50 Nanyang Ave., School of MAE, Singapore, 639798, Singapore,<br />

kan626@gmail.com, Leon McGinnis<br />

We propose a new approximation approach, based on observed properties of the<br />

behavior of tandem queues, which we call the intrinsic gap and intrinsic ratio.<br />

The approach exploits what we call the nearly-linear and heavy-traffic properties<br />

of the intrinsic ratio, which appear to hold in realistic production situations.<br />

Across a broad range of examined cases, this new approach outperforms earlier<br />

approximation methods and offers a way to analyze the dependence among<br />

servers.


2 - A Queueing System with Service Phases of Random Length<br />

and Vacations<br />

George Mytalas, Athens University of Economics and Business,<br />

76 Patission Str., Athens 104 34, Athens, Greece, mytalas@aueb.gr,<br />

Michael Zazanis<br />

We examine a queueing model with Poisson arrivals, vacations and service phases<br />

of random length with distributions with bounded or unbounded support.<br />

Standard techniques are used involving RouchÈ’s theorem and Wiener-Hopf<br />

factorization techniques. We obtain our results under minimal assumptions,<br />

namely the finiteness of the first moment of the service and vacation distributions<br />

together with the stability condition.<br />

3 - Real-time Delay Estimation in Multi-class Many-server<br />

Queueing Systems<br />

Zinan Yi, PhD Student, North Carolina State University, Room 304,<br />

1430 Collegeview Ave., Raleigh, NC, 27606-3133, United States of<br />

America, zyi@ncsu.edu, Yunan Liu, Rouba Ibrahim<br />

We develop real-time delay estimators for multi-class queueing networks with<br />

general service and patience distributions, time-varying arrival rates and staffing<br />

functions, skill-based routing and global first-come-first-served service discipline.<br />

To construct these estimators, we adopt the corresponding many-server heavytraffic<br />

fluid models. Computer simulation experiments verify that these estimators<br />

are effective.<br />

4 - Efficient Queuing Network Structures with Limited Flexibility<br />

Kuang Xu, Massachusetts Institute of Technology, 77<br />

Massachusetts Avenue, Cambridge, MA, United States of America,<br />

kuangxu@mit.edu, John N. Tsitsiklis<br />

We study a multi-server model where n flexible servers are connected to rn<br />

queues through a fixed connectivity graph, with average degree d. We show that<br />

as n tends to infinity, both a diminishing delay and a large capacity region are<br />

jointly achievable, even under limited flexibility (d


SC60<br />

■ SC60<br />

60- Remington- Hyatt<br />

Efficient Models and Algorithms for Air Traffic<br />

Flow Management<br />

Sponsor: Aviation Applications<br />

Sponsored Session<br />

Chair: Vikrant Vaze, Member Research Staff, Philips Research North<br />

America, 345 Scarborough Road, Briarcliff Manor, NY, 10510,<br />

United States of America, vikrant.vaze@philips.com<br />

1 - Equipage-based Resource Allocation in Air Traffic Flow<br />

Management<br />

Shervin AhmadBeygi, Lead Operations Research Analyst, Metron<br />

Aviation Inc., 45300 Catalina Ct, Dulles, VA, 20166, United States<br />

of America, shervin.ahmadbeygi@metronaviation.com<br />

Successful implementation of the Next Generation Air Transportation System<br />

(NextGen) requires a critical mass of aircraft to be equipped with a range of<br />

communication, navigation, and surveillance avionics. In this research we study<br />

different mechanisms to incorporate equipage information in Traffic Flow<br />

Management resource allocation algorithms.<br />

2 - A Decomposition Approach for the Stochastic ATFM Problem<br />

L. Corlli, University of Milano-Bicocca, Department Informatics<br />

Systems Communication, Milano, 20126, Italy,<br />

corolli@disco.unimib.it, Lewis Ntaimo, Guglielmo Lulli<br />

The stochastic Air traffic Flow Management (ATFM) problem is now attracting a<br />

lot of interest from the research community. In this talk, we present a two-stage<br />

stochastic integer programming formulation for the problem, which balance the<br />

trade-off between the complexity of the model and its representation of reality. To<br />

solve the problem, we present a decomposition approach to take advantage of the<br />

underlying structure of the problem.<br />

3 - Applying Air Traffic Flow Management Optimization Models to<br />

Railroad Train Scheduling<br />

Lingyun Meng, School of Traffic and Transportation, 8507D, No.8<br />

Teaching Building, No.3 ShangYuanCun, HaiDian District, China,<br />

lymeng@bjtu.edu.cn, Xuesong Zhou<br />

By analyzing a variety of air traffic flow management models, this paper proposes<br />

a cumulative flow count based optimization model for train scheduling problem<br />

under stochastic segment capacity breakdowns. The “capacity aggregation”<br />

technique is used to capture the uncertainty of capacity breakdown incidents. A<br />

Lagrangian relaxation based solution approach is presented to solve this model.<br />

Numerical experiments are conducted to demonstrate the performance of the<br />

proposed solution approach.<br />

4 - Application and Evaluation of Bibliometrics Methods for<br />

ATM Researches<br />

Hidenori Chida, University of Tokyo, Hongo 7-3-1, Bunkyo-ku,<br />

Tokyo, Japan, hidenori.chida@gmail.com, Katsuhiro Nishinari,<br />

Hiroko Nakamura<br />

Innovation in ATM (air traffic management) is expected to afford rapidly<br />

increasing air traffic more efficiently and safely. To implement the innovation,<br />

interdisciplinary cooperation is required in ATM researchers such as with civil<br />

engineering or navigation research of other transportation. Therefore, we applied<br />

and evaluated a bibliometrics method to get overviews of areas unknown to ATM<br />

researchers, and to support effective and strategic ATM development.<br />

■ SC61<br />

61- Russell- Hyatt<br />

Airport Operations<br />

Sponsor: Aviation Applications<br />

Sponsored Session<br />

Chair: Mourad Boudia, Research Engineer, Amadeus, 485,<br />

Route du Pin Montard BP 69, Sophia Antipolis, 06902, France,<br />

mourad.boudia@amadeus.com<br />

1 - Pre-departure Sequence Planning<br />

Mourad Boudia, Research Engineer, Amadeus, 485,<br />

Route du Pin Montard BP 69, Sophia Antipolis, 06902, France,<br />

mourad.boudia@amadeus.com, Olivier Ratier, Baptiste Chatrain<br />

High performance departure sequence planning contributes to improve air traffic<br />

and aircraft operations at airports by maximizing usage of available runways. We<br />

present here an innovative approach based on linear programming and discuss its<br />

contribution and performances.<br />

INFORMS Phoenix – 2012<br />

126<br />

2 - Aircraft Stand Allocation with Associated Resource Scheduling<br />

Tor Fog Justesen, Industrial PhD Student, Copenhagen Airports<br />

A/S, Lufthavnsboulevarden 6, P.O. Box 74, Kastrup, 2770,<br />

Denmark, tor.justesen@cph.dk, Richard Lusby, Jesper Larsen,<br />

David Ryan<br />

When handling an aircraft turnaround different ground handling resources are<br />

required at different times. Each resource can be claimed by at most one<br />

turnaround at a time. In this project we develop a set partitioning model<br />

formulation of the aircraft stand allocation problem with associated resource<br />

scheduling and an optimization based solution algorithm in which knowledge<br />

about the structure of the problem is exploited to generate good feasible solutions.<br />

3 - Maximizing Resilience of Airport Runway and Taxiway<br />

Pavement Networks through Stochastic Programming<br />

Reza Faturechi, PhD Candidate, University of Maryland, 1173<br />

Glenn L. Martin Hall, College Park, MD, 20742, United States of<br />

America, reza@umd.edu, Xiaodong Zhang, Eyal Levenberg,<br />

Elise Miller-Hooks<br />

A two-stage binary integer, stochastic program and integer L-shaped method<br />

proposed for its solution are presented for assessing and maximizing the resilience<br />

of an airport given the possibility of future, randomly arising events affecting<br />

airport runway and taxiway pavement networks. Their application provides<br />

insights into optimal allocation of limited resources for response and preparedness<br />

actions that facilitate them. The approach is demonstrated on a case study<br />

involving Laguardia Airport.<br />

4 - Stand Allocation in Airports - New Solution Approaches<br />

and Results<br />

Rodrigo Acuna Agost, Operations Research-Innovation, Amadeus,<br />

485 Route du Pin Montard, Sophia Antipolis, 06902, France,<br />

rodrigo.acunaagost@amadeus.com, Mourad Boudia, Thierry<br />

Delahaye, Julien Guepet, Daniel Perez<br />

The Stand Allocation Problem consists in finding an assignment of aircraft<br />

turnarounds to parking positions. The usual objectives include maximizing the<br />

number of passenger assigned to contact stands, and minimizing the number of<br />

tows. In this talk we show new methods including MIP-based, CP-based, Column<br />

Generation, and metaheuristics approaches. The results of experiments show<br />

significant improvements on several KPIs compared to the current practice on real<br />

data from two European airports.<br />

■ SC62<br />

62- Borein A - Hyatt<br />

Automated Analysis and Design of Auctions<br />

Cluster: Auctions<br />

Invited Session<br />

Chair: David Thompson, PhD Student, University of British Columbia,<br />

191-2366 Main Mall, Vancouver, BC, V6T 1Z4, Canada,<br />

davidrthompson@gmail.com<br />

1 - Automated Mechanism Design, with Applications to Auctions<br />

Yevgeniy Vorobeychik, Sandia National Labs, 7011 East Ave.,<br />

Livermore, CA, 94550, United States of America,<br />

eug.vorobey@gmail.com<br />

We present general methods for automated mechanism design when both the<br />

design, and player strategy spaces are constrained. We offer Bayesian and worstcase<br />

(“robust”) formulations, and present a technique based on stochastic search.<br />

Finally, we demonstrate the effectiveness of our methods in a variety of auction<br />

settings.<br />

2 - Automated Mechanism Design using CAT Games<br />

Jinzhong Niu, Postdoctoral Research Associate, The City College of<br />

New York, 160 Convent Avenue, New York, NY, 10031,<br />

United States of America, jniu@ccny.cuny.edu, Simon Parsons<br />

In this paper, we present a genetic algorithm-based approach to automated design<br />

of complete auction mechanisms in the domain of CAT games. In a CAT game,<br />

multiple players, each providing his/her own design of a double-sided auction,<br />

compete against each other to attract traders for more profit and high transaction<br />

success rate. We show that this evolutionary method is effective in creating<br />

auction mechanisms in the CAT setting.<br />

3 - Revenue Optimization and the Generalized Second-price<br />

Auction<br />

David Thompson, PhD Student, University of British Columbia,<br />

191-2366 Main Mall, Vancouver, BC, V6T 1Z4, Canada,<br />

davidrthompson@gmail.com<br />

Search engines generate billions of dollars in advertising revenue using the<br />

generalized second-price auction (GSP). They have tried to further increase<br />

revenue using GSP variants including different kinds of reserve prices, and<br />

quality-score squashing. Our contributions are a comparison of different reserve<br />

price regimes (with and without squashing) and a study of how equilibrium<br />

selection affects the revenue generated by these variants.


4 - Profit-charging Market Makers with Bounded Loss, Vanishing<br />

Bid/Ask Spreads, and Unlimited Depth<br />

Tuomas Sandholm, Carnegie Mellon University, Computer Science<br />

Dept., Pittsburgh PA , United State of America,<br />

sandholm@cs.cmu.edu, Abe Othman<br />

It was an open question whether a market maker can simultaneously satisfy<br />

bounded loss, the ability to make a profit, a vanishing bid/ask spread, and<br />

unlimited market depth. We design market makers that do. We achieve this by<br />

introducing a practical framework that extends constant-utility cost functions<br />

with two functions that are added to the prices quoted to the trader: the liquidity<br />

function uses its proceeds to increase the liquidity, and the profit function is a<br />

“lockbox” of savings.<br />

■ SC63<br />

63- Borein B- Hyatt<br />

Joint Session Behavioral/HAS: Antecedents and<br />

Consequences of Worker and Patient Behaviors in<br />

Health Care Settings<br />

Sponsor: Behavioral Operations & Health Applications Society<br />

Sponsored Session<br />

Chair: Anita Tucker, Associate Professor and Marvin Bower Fellow,<br />

Harvard University, 413 Morgan Hall, Soldiers Field, Boston, MA,<br />

02478, United States of America, atucker@hbs.edu<br />

Co-Chair: Reidar Hagtvedt, Assistant Professor of Management Science<br />

and Statistics, University of Alberta School of Business, 2-43 Business<br />

Building, Edmonton, AB, T6G2C7, Canada,<br />

reidar.hagtvedt@business.ualberta.ca<br />

1 - Speaking Up About Internal Supply Chain Problems:<br />

Experiments on Medication Administration<br />

Anita Tucker, Associate Professor and Marvin Bower Fellow,<br />

Harvard University, 413 Morgan Hall, Soldiers Field, Boston, MA,<br />

02478, United States of America, atucker@hbs.edu<br />

Employees who experience internal supply chain problems can provide valuable<br />

information about improvement opportunities. To understand the conditions<br />

under which employees are more likely to speak up about problems, we ran<br />

experiments using medication administration tasks for which we purposely<br />

created problems. Nurse spoke up under two conditions: (1) to obtain materials if<br />

there was no other way to work around the issue and (2) when their role identity<br />

was primed to include improvement.<br />

2 - Desensitization to Stimuli and Optimal Expenditures to Increase<br />

Hand-hygiene in Hospitals<br />

Reidar Hagtvedt, Assistant Professor of Management Science and<br />

Statistics, University of Alberta School of Business,<br />

2-43 Business Building, Edmonton, AB, T6G2C7, Canada,<br />

reidar.hagtvedt@business.ualberta.ca, Sarah Forgie<br />

Hand hygiene in hospitals is typically lower than recommended by the WHO. One<br />

strategy for change is to run educational campaigns, although empirical studies<br />

show health-care workers are aware of the importance of hand-hygiene. Such<br />

campaigns eventually recede into the background. We have purchased sensors for<br />

gel dispensers, in order to establish baseline usage and forgetting rates, which will<br />

then serve as input to a model to optimize resources used to increase handhygiene<br />

compliance.<br />

3 - Multi-server Systems with Adaptive Server Behavior<br />

Mohammad Delasay, Alberta School of Business, University of<br />

Alberta, Edmonton, AB, T6G2R6, Canada, delasays@ualberta.ca,<br />

Armann Ingolfsson, Bora Kolfal<br />

We investigate service rates in the Calgary EMS system and show that service<br />

rates decrease with the number of busy ambulances. Then, we model and analyze<br />

systems in which service rates change with “load” (the number of busy servers)<br />

and “overwork” (the number of users served in the current full busy period). We<br />

demonstrate how ignoring adaptive server behavior results in inconsistencies<br />

between the planned and realized performance.<br />

4 - Health Care Supply Chain for Behavioral Health: Evaluating<br />

Community Environment and Primary Care<br />

David Zepeda, Assistant Professor, University of Minnesota,<br />

Minneaplis, MN, United States of America, zepe0003@umn.edu,<br />

Kingshuk K. Sinha<br />

One in four people experience a behavioral health condition in their lifetime.<br />

Making treatment affordable and cost effective requires the integration of<br />

behavioral and physical care through primary care. Yet, the community<br />

environment can also influence behavioral health. Using clinic and community<br />

level data we evaluate the effects of the community environment (physical and<br />

social) and quality primary care (technology-enabled, evidence based, and<br />

affordable) on improving behavioral health.<br />

INFORMS Phoenix – 2012<br />

127<br />

■ SC66<br />

66- Ellis West- Hyatt<br />

Data Mining and OR in Health Application<br />

Sponsor: Data Mining<br />

Sponsored Session<br />

Chair: Sung Won Han, Fellow, Hoffmann-La Roche Inc., 340 Kingsland<br />

St., Nutley, NJ, United States of America, sung_won.han@roche.com<br />

1 - A Comparison of MCUSUM-based and MEWMA-based<br />

Surveillance Methods in Non-homogeneous Population<br />

Sung Won Han, Fellow, Hoffmann-La Roche Inc.,<br />

340 Kingsland St., Nutley, NJ, United States of America,<br />

sung_won.han@roche.com<br />

Motivated by applications in healthcare surveillance, we studied the<br />

spatiotemporal surveillance problem of detecting the mean change of Poisson<br />

count data in non-homogeneous populations. We investigate several likelihood<br />

ratio-based approaches and EWMA-based methods and compare them under<br />

various scenarios. We discuss under which scenarios the EWMA-based methods<br />

are more robust than the likelihood ratio-based approaches.<br />

2 - Dynamic Spatiotemporal Warping for the Detection and<br />

Localization of Heart Attacks<br />

Hui Yang, Assistant Professor, University of South Florida,<br />

Tampa, FL, 33620, United States of America, huiyang@usf.edu<br />

Myocardial infarction (MI), also known as heart attack, is the leading cause of<br />

death. This paper presents a novel warping approach to quantify the dissimilarity<br />

of disease-altered patterns in 3-lead VCG signals. The hypothesis testing shows<br />

there are significant space-time signal pattern variations between healthy controls<br />

(HC) and various MIs. The new approach yields an accuracy of 94.7% for<br />

separating MIs and HCs and an accuracy of 96.5% for anterior-related MIs and<br />

inferior-related MIs.<br />

3 - Predicting Sequential Health Events<br />

Benjamin Letham, Massachusetts Institute of Technology,<br />

Operations Research Center, Cambridge, MA, United States of<br />

America, bletham@mit.edu, David Madigan, Cynthia Rudin<br />

Using a database of sequences of health events, we wish to learn a predictor that<br />

can use a patient’s current medical history to predict future health events. We use<br />

ideas from supervised ranking to develop a framework for sequential predictions<br />

that allows for a variety of modeling choices. We apply our method to health<br />

event data from a clinical trial and demonstrate good performance.<br />

4 - Contact Network Based Risk Assessment to Prevent<br />

Potential Pandemics<br />

Shengpeng Jin, Teaching Asistant, University of Louisville, 782<br />

Frederick Stamm Ct. Apt #4, 4, Louisville, KY, 40217, United<br />

States of America, jinshengpeng@gmail.com, Suraj Alexander<br />

Early information is crucial for policy makers and public health officials. Current<br />

indicators of the spread of contagious outbreaks lag behind the actual spread of<br />

the epidemic, leaving no time for a planned response. Our focus, however, is on<br />

the effective control of the spread of contagious outbreaks in their early stages. In<br />

this paper, we use information from “central” individuals in “contact” networks<br />

for early “spatial - temporal” prediction of virulent contagious outbreaks.<br />

■ SC67<br />

SC67<br />

67- Ellis East- Hyatt<br />

Data Fusion for Manufacturing System Performance<br />

Improvement II<br />

Sponsor: Quality, Statistics and Reliability<br />

Sponsored Session<br />

Chair: Ran Jin, Assistant Professor, Virginia Tech., 1145 Perry St.,<br />

Blacksburg, VA, 24060, United States of America, jran5@vt.edu<br />

Co-Chair: Jian Liu, Assistant Professor, The University of Arizona, Rm<br />

221 ENGR Building, 1127 E. James E. Rogers Way, Tucson, AZ, 85721,<br />

United States of America, jianliu@sie.arizona.edu<br />

1 - Surface Variation Monitoring by Integrating Spatial Data with<br />

Cutting Force Models<br />

Hui Wang, University of Michigan, Ann Arbor, MI,<br />

United States of America, huiwz@umich.edu<br />

Variation control of surface shape becomes a key enabler of high-precision<br />

machining. This talk presents a method for efficiently measuring and monitoring<br />

variations of machined surfaces. Cutting force modeling is conducted and is<br />

correlated with surface spatial data to improve surface profile prediction. Using<br />

the prediction, a strategy under Bayesian framework is proposed to monitor<br />

surface variations without significantly increasing false alarms. A Ford case study<br />

demonstrates the method.


SC68<br />

2 - The Use of Spatial Statistical Analysis for Image Based<br />

Part Inspection<br />

Jaime Camelio, Associate Professor, Virginia Tech, 235 Durham<br />

Hall, Blacksburg, VA, United States of America, jcamelio@vt.edu,<br />

Lee Wells<br />

Traditional quality control tools are based upon extracting features and measuring<br />

discrete dimensional data. However, new data-sets that are highly heterogeneous<br />

(multiple sensor types measuring different phenomena) and data-rich (thousands<br />

or even millions of data points). This presentation will use a case study of highspeed<br />

micro-scale part inspection using digital images and 3D laser scanning data.<br />

A cross-sensor spatial inspecting technique will be presented and its performance<br />

analyzed.<br />

3 - Informative Sensor and Feature Selection via Hierarchical Non-<br />

Negative Garrote<br />

Kamran Paynabar, University of Michigan, Ann Arbor, MI,<br />

United States of America, kamip@umich.edu<br />

In order to effectively extract the information from a distributed sensing system, it<br />

is essential to develop a systematic method that not only can select important<br />

sensors/signals, but also can extract a low dimension of interpretable features<br />

from the high-dimensional vector of a selected signal. For this purpose, we<br />

develop a new hierarchical regularization approach called hierarchical nonnegative<br />

garrote. Performance of the method is evaluated through simulations<br />

and a case study.<br />

4 - Damage Identification for High-Speed Train Gearbox Shell<br />

Material Base on Acoustic Emission Technology<br />

Weidong Zhang, University of Science & Technology Beijing,<br />

30 Xueyuanroad, Haidian District, Beijing, 100083, China,<br />

zwd@ustb.edu.cn, Xiwen Zhang<br />

The failure of high-speed train gearbox shell material is very important for the<br />

safety of high-speed train.In this paper,we use acoustic emission technology to<br />

monitor the the degree of damage in high-speed train gearbox shell material.The<br />

research work includes two main aspects: the data pre-processing method for<br />

imbalanced dataset and SVM modification method for imbalanced dataset. Then<br />

we apply these methods in the damage identification of high-speed train gearbox<br />

shell material.<br />

5 - Engineering Driven Force Model Enhancement for the Laser<br />

Assisted Micro Milling (LAMM) Process<br />

Chia-Jung Chang, Georgia Institute of Technology, 765 Ferst Drive,<br />

Main Building, Office 217, Atlanta, GA, 30332-0205,<br />

cchang43@gatech.edu, Mukund Kumar, Roshan Vengazhiyil,<br />

Shreyes N. Melkote<br />

LAMM is capable of generating three dimensional microscale features in hard<br />

metals. An engineering-driven force model that captures the effect of thermal<br />

softening due to laser heating has been developed. We proposed a systematic way<br />

to estimate unknown model parameters with experimental force measurements.<br />

This model provides accurate force predictions over a range of production<br />

conditions in a timely manner which facilitates the LAMM process optimization<br />

to yield the maximal force reduction.<br />

■ SC68<br />

68- Suite 312- Hyatt<br />

Finance: Theory and Empirics<br />

Contributed Session<br />

Chair: Yunchao Xu, National University of Singapore, Mochtar Riady<br />

Building, BIZ 1 8-69, 15 Kent Ridge Drive, Singapore, 119245,<br />

Singapore, bizxuy@nus.edu.sg<br />

1 - Asset Price Bubbles in Experimental Markets<br />

Vinod Cheriyan, Georgia Institute of Technology,<br />

755 Ferst Drive NW, Atlanta, GA, 30332, United States of America,<br />

vinod.cheriyan@gatech.edu, Anton Kleywegt, Federico Bonetto<br />

Asset price bubbles have been observed in experimental markets. However, in<br />

most of these studies the supply and demand of assets are specified exogenously.<br />

Also, their finite duration causes end of the horizon effects. In this work, we<br />

design an experimental market with endogenous supply and demand, and<br />

random duration. We show that asset price bubbles are possible in such markets.<br />

We present findings from our experiments. We also fit our model and other<br />

models of investor behavior to the data.<br />

2 - How to Make Optimal Instruments for GMM More Efficient<br />

Stephen Goldberger, University of North Carolina at Chapel Hill,<br />

Chapel Hill, NC, United States of America, sgoldber@live.unc.edu<br />

For instrumental variables estimation of time series models with martingale<br />

difference sequence errors the optimal instruments are known but unobserved.<br />

We use mixed frequency data in order to create improved feasible optimal<br />

instruments, which in turn leads to more efficient parameter estimation.<br />

INFORMS Phoenix – 2012<br />

128<br />

3 - Minimum Quadratic Benchmark Regret in Portfolio Optimization<br />

Yunchao Xu, National University of Singapore, Mochtar Riady<br />

Building, BIZ 1 8-69, 15 Kent Ridge Drive, Singapore, 119245,<br />

Singapore, bizxuy@nus.edu.sg, Zhichao Zheng, Chung Piaw Teo,<br />

Karthik Natarajan<br />

We propose a minimum quadratic benchmark regret model to decide optimal<br />

portfolio weights, which combines flavor of traditional regret and tracking<br />

models. We provide closed-form expressions of the optimal portfolio weights,<br />

with or without consideration of transaction volumes, when the risky asset<br />

returns follow a multivariate normal distribution. Our portfolios demonstrate<br />

superior out-of-sample performance compared to numerous portfolio strategies<br />

studied in the literature.<br />

■ SC69<br />

69- Suite 314- Hyatt<br />

Portfolio Management in Frictional Markets<br />

Cluster: Optimization in Finance<br />

Invited Session<br />

Chair: Gerry Tsoukalas, University of Pennsylvania, The Wharton<br />

School, Philadelphia, PA, United States of America,<br />

gtsouk@wharton.upenn.edu<br />

Co-Chair: Dan Iancu, Assistant Professor, Graduate School of Business,<br />

Stanford University, Stanford, CA, 94305, United States of America,<br />

daniancu@stanford.edu<br />

1 - Fairness and Efficiency in Multiportfolio Optimization<br />

Nikos Trichakis, Assistant Professor, Harvard Business School,<br />

Boston, MA, United States of America, ntrichakis@hbs.edu,<br />

Dan Iancu<br />

When a manager is in charge of multiple accounts, the performance of each<br />

account depends on the strategies of others due to market impact. We propose a<br />

novel approach for jointly optimizing the trading activities of all accounts and also<br />

splitting the associated market impact costs. Our approach allows one to balance<br />

the conflicting objectives of maximizing aggregate gains and distributing them<br />

fairly. We perform numerical studies that suggest that our approach outperforms<br />

existing methods.<br />

2 - Optimal Dynamic Portfolio Construction with Transaction Costs<br />

John Birge, Professor, University of Chicago, Chicago, IL,<br />

United States of America, john.birge@chicagobooth.edu<br />

Challenges for practical portfolio optimization include both time-varying return<br />

distributions and the presence of transaction costs. We consider simultaneous<br />

portfolio optimization and parameter estimation in a GARCH model with<br />

proportional transaction costs using consistent estimates of the opportunity cost of<br />

sub-optimal positions.<br />

3 - Estimation Risk in Dynamic Portfolio Optimization<br />

Alberto Martin-Utrera, Mr, University Carlos III of Madrid,<br />

C/ Madrid, 126-28903, GETAFE, Sp, 28903,<br />

amutrera@est-econ.uc3m.es, Francisco J. Nogales, Victor DeMiguel<br />

We consider an investment decision problem for an investor whose objective<br />

function is to maximize her lifetime utility in the presence of trading costs. We<br />

study the effects of estimation error of the estimated optimal trading strategy<br />

within the investor’s expected utility, and we propose several shrinkage methods<br />

to mitigate the effects of estimation error.


■ SC70<br />

70- Suite 316- Hyatt<br />

Theoretic Approach and Optimal<br />

Coordination Policies<br />

Sponsor: Information Systems<br />

Sponsored Session<br />

Chair: Monica Johar, Assistant Professor, University of North Carolina<br />

at Charlotte, 9201 University City Blvd, Charlotte, NC,<br />

United States of America, msjohar@uncc.edu<br />

1 - Optimal Information System Security Investment – A Control<br />

Theoretic Approach<br />

Jing Zhou, Assistant Professor, University of North Carolina-<br />

Charlotte, 9201 University City Blvd, Friday 353C, Charlotte, NC,<br />

28223, United States of America, jzhou7@uncc.edu, Xun Li,<br />

Monica Johar<br />

Most of the IT security investment literature is based on single period analysis. In<br />

addition to the initial investment, a firm continues to exert effort to maintain the<br />

effectiveness of the IT infrastructure. We use a control theoretic framework to<br />

find the optimal IT security investment to minimize the expected total cost over a<br />

planning horizon. Our results can help firms decide how to invest in IT security<br />

given the type of the information system and the efficiency of the investment.<br />

2 - Optimal Coordination Policies in Distributed<br />

Software Development<br />

Vijay Mookerjee, University of Texas at Dallas, 800 W. Campbell<br />

Road, Richardson, TX, 75080, United States of America,<br />

vijaym@utdallas.edu<br />

We study the problem of designing optimal coordination policies in distributed<br />

software development (DSD). Coordination in DSD can be both within one site<br />

and across different sites. The latter type coordination involves communication<br />

across spatial boundaries (different locations) and possibly temporal boundaries<br />

(different time zones) and is the main challenge that DSD faces. We consider both<br />

symmetric and aymmetric sites with randomness.<br />

3 - Analyzing the Influence of Minimum Requirements on Coupon<br />

Selling in Groupon’s Daily Deal<br />

Gang Wang, University of Connecticut, 2100 Hillside Road, Storrs,<br />

CT, United States of America, gang.wang@business.uconn.edu,<br />

James Marsden, Xue Bai, Bill Ross<br />

Minimum requirements have been one of the key features in Groupon’s daily<br />

deal setting in which a certain number of coupons must be bought to activate the<br />

deal. Comparing two groups of Groupon deals, those with and those without<br />

minimum requirements, we isolate the influence of minimum requirements on<br />

social sharing, indicated by Facebook likes, and then analyze possible impacts on<br />

coupon sales and revenue for various retail categories.<br />

■ SC71<br />

71- Suite 318- Hyatt<br />

Economics of Information Systems<br />

Sponsor: eBusiness<br />

Sponsored Session<br />

Chair: Mingfeng Lin, University of Arizona, 1130 E. Helen St, Tucson,<br />

AZ, 85721, United States of America, mingfeng@eller.arizona.edu<br />

1 - Optimal Choice for Market Price Information<br />

Chris Parker, Pennsylvania State University, Smeal College of<br />

Business, University Park, PA, 16802, United States of America,<br />

chris.parker@psu.edu, Kamalini Ramdas, Nicos Savva<br />

Information is only valuable if it is both new and actionable. We model a seller’s<br />

selection of a market for which to purchase price information. We discuss the<br />

results of the model in the context of farmers in rural India and use data to<br />

analyze whether actual decisions are in line with our model.<br />

2 - The Impact of IT on Economic Capacity<br />

Dawei Zhang, University of Calgary, Haskayne School of Business,<br />

Calgary, Canada, dzhang@ucalgary.ca, Barrie Nault<br />

We define economic capacity as the output level that maximizes short-run<br />

industry profit, and empirically explore the impact of IT on economic capacity and<br />

CU under a production function framework.<br />

INFORMS Phoenix – 2012<br />

129<br />

3 - Content Sharing in a Social Broadcasting Environment:<br />

Evidences from Twitter<br />

Huaxia Rui, University of Texas at Austin, Austin, TX,<br />

United States of America, huaxia@utexas.edu<br />

We collect a detailed dataset about the information-sharing activity on Twitter,<br />

called retweet, and estimate an econometric model regarding tie strength and<br />

retweeting behavior. The empirical results convincingly support our model and<br />

we find that after an author posts a median quality (as defined in the sample)<br />

tweet, the likelihood that a unidirectional follower will retweet is significantly<br />

higher than the likelihood that a bidirectional follower will.<br />

4 - Geography in Online Peer-to-peer Lending<br />

Mingfeng Lin, University of Arizona, 1130 E. Helen St., Tucson,<br />

AZ, 85721, United States of America, mingfeng@eller.arizona.edu,<br />

Siva Viswanathan<br />

We study how geography affects investors’ choice of loans to fund using data<br />

from Prosper.com, one of the largest online peer-to-peer lending websites. Using<br />

data from regular market conditions and from a natural experiment, we show<br />

that geography affects lender decisions, but this relationship is moderated by the<br />

nature of the loan request and the salience of geography in the marketplace.<br />

■ SC72<br />

SC72<br />

72- Suite 322- Hyatt<br />

Resource Management<br />

Cluster: Cloud Computing<br />

Invited Session<br />

Chair: Natarajan Gautam, Associate Professor, Texas A&M University,<br />

3131 TAMU, College Station, TX, 77843, United States of America,<br />

gautam@tamu.edu<br />

1 - Efficient Management of Demand Loads in Cloud Computing<br />

Environments<br />

Samyukta Sethuraman, Texas A&M University, 3131 TAMU,<br />

College Station, TX, 77843, United States of America,<br />

samyukta@tamu.edu, Natarajan Gautam, Lewis Ntaimo<br />

Energy efficiency can be achieved in cloud computing environments by cleverly<br />

assigning applications to servers, routing requests to appropriate servers, and<br />

speed-scaling of servers. We formulate and solve an optimization problem that<br />

minimizes expected energy consumption subject to satisfying QoS constraints. We<br />

develop a hybrid model that combines a deterministic optimization model and a<br />

stochastic fluid flow analysis in a unified manner.<br />

2 - A Method to Generate Image for SPC by Point Cloud Data<br />

Ketai He, Associate Professor, University of Science and<br />

Technology Beijing, No. 30, Xueyuan Rd., Haidian Dist., Beijing,<br />

100083, China, ketaih@vt.edu, Jaime Camelio, Fadel Megahed<br />

Image analysis is an important method of statistical process control in<br />

manufacturing. It is difficult to obtain suitable images for defect detection and<br />

analysis when products have irregular surfaces. Three-dimension surface scanner<br />

can get the surface information, but the data is difficult to analyze directly due to<br />

massive data points. We propose a method to generate image by point cloud data<br />

from surface scanner, which can be used in defect analysis.<br />

3 - Optimal Arrival and Service Rate Control of Multi-server Queues<br />

with Application to Could Computing<br />

Nelson Lee, Department of Statistics and Operations Research,<br />

University of North Carolina, Chapel Hill, NC, 27599,<br />

United States of America, leent@email.unc.edu,<br />

Vidyadhar Kulkarni<br />

We consider the problem of optimal control of a multi-server queue with<br />

controllable arrival and service rates. This study is motivated by its potential<br />

application to the design and control of data centers or cloud computing facilities.<br />

The cost structure includes customer holding cost, server operating cost, and<br />

system operating reward. We derive structural properties of the optimal control<br />

policies under both discounted cost and average cost criterions.


SC73<br />

■ SC73<br />

73- Suite 324- Hyatt<br />

Computational Finance I<br />

Cluster: Quantitative Finance<br />

Invited Session<br />

Chair: Nan Chen, Assistant Professor, The Chinese University of Hong<br />

Kong, Shatin, N.T., Hong Kong, Hong Kong - PRC,<br />

nchen@se.cuhk.edu.hk<br />

1 - Coco, Bail-in and Tail Risk<br />

Nan Chen, Assistant Professor, The Chinese University of Hong<br />

Kong, Shatin, N.T., Hong Kong, Hong Kong-PRC,<br />

nchen@se.cuhk.edu.hk, Paul Glasserman, Behzad Nouri<br />

We develop a capital structure model to analyze the incentives created by<br />

contingent convertibles (Cocos) and bail-in debt, two variants of debt that<br />

converts to equity as a bank nears or reaches financial distress. Our model<br />

combines endogeous default, debt rollover, and jump risks. We find that Cocos<br />

generally have positive incentive effects when the conversion trigger is not set too<br />

low.<br />

2 - Optimal Deleveraging with Market Impact<br />

Jingnan Chen, University of Illinois at Urbana-Champaign,<br />

Urbana, IL, 61801, United States of America, jchen98@illinois.edu,<br />

Jiming Peng, Liming Feng, Yinyu Ye<br />

We consider an optimal liquidation problem where the objective is to meet<br />

specified leverage ratio at the minimal cost. Under linear price impact, the<br />

problem reduces to a generally non-convex quadratic program with quadratic and<br />

box constraints. We derive some analytical results regarding the optimal<br />

liquidation strategy. A Lagrangian method is proposed to solve the problem<br />

numerically.<br />

3 - Consistent Pricing of Options on Leveraged ETFs<br />

Martin Haugh, Columbia University IE&OR, 500 West 120th<br />

Street, Mudd 332, New York, NY, 10027, United States of America,<br />

mh2078@columbia.edu, Andrew Ahn, Ashish Jain<br />

We consider the problem of pricing options on leveraged ETFs in a manner that is<br />

consistent with the pricing of options on the underlying security. The difficulty is<br />

that tractable underlying price dynamics do not in general translate into tractable<br />

LETF dynamics. We overcome this problem by approximating the LETF dynamics<br />

so that approximate LETF option prices can be computed very quickly via<br />

standard transform methods. We justify our approximations via Monte-Carlo<br />

experiments.<br />

4 - Rare Event Simulation for Portfolio Default Losses<br />

Xiaowei Zhang, HKUST, Hong Kong, Hong Kong-PRC,<br />

xiaoweiz@ust.hk<br />

We use a self-exciting point process L(t) to model the default losses of a portfolio.<br />

Fixing the time horizon t, we develop an importance sampling (IS) simulation for<br />

estimating P(L(t)>x), i.e. the probability that the portfolio suffers a large default<br />

loss before time t. We will show that this IS scheme achieves a significant variance<br />

reduction compared to plain Monte Carlo simulation.<br />

<strong>Sunday</strong>, 4:30pm - 6:00pm<br />

■ SD01<br />

01- West 101- CC<br />

Joint Session Opt-Global/ENRE-Energy: Global<br />

Optimization in Energy<br />

Sponsor: Optimization/Global Optimization & Energy, Natural Res &<br />

the Environment/Energy<br />

Sponsored Session<br />

Chair: Steffen Rebennack, Assistant Professor of Operations Research,<br />

Colorado School of Mines, 1500 Illinois St., Golden, CO, 80401,<br />

United States of America, srebenna@mines.edu<br />

Co-Chair: Timo Lohmann, PhD Student, Colorado School of Mines,<br />

816 15th Street, Golden, CO, 80401, United States of America,<br />

tlohmann@mines.edu<br />

1 - Decomposition Strategies for Stochastic Mixed-integer<br />

Nonlinear Programs with Energy Applications<br />

Paul I. Barton, Lammot du Pont Professor, Massachusetts Institute<br />

of Technology, 77 Massachusetts Avenue, 66-464, Cambridge, MA,<br />

02139, United States of America, pib@mit.edu<br />

We present a recently developed deterministic global optimization approach with<br />

running time that scales linearly with the number of scenarios considered. This<br />

INFORMS Phoenix – 2012<br />

130<br />

enables the solution of large-scale instances of problems that arise in the<br />

optimization of a variety of energy systems under uncertainty, such as the<br />

planning of natural gas production infrastructure, the design of flexible energy<br />

polygeneration systems, feedstock selection for oil refineries, etc.<br />

2 - The Optimal Power Flow Problem Model as a MILP<br />

(Mixed-Integer Linear Programming)<br />

Maria de Luján Latorre, Researcher, PSR, Praia de Botafogo<br />

228/1701-A Botafogo, Rio de Janeiro, RJ, 22250-145, Brazil,<br />

lujan@psr-inc.com, Sérgio Granville, Mario Veiga Pereira,<br />

Rafael Ferreira, André Dias<br />

The OPF problem determines the optimal operation of generation and<br />

transmission system representing the AC network constraints in an integrated<br />

form. In this work we apply McCormick inequalities and disjunctive constraints to<br />

linearize the original nonlinear and non-convex optimization problem. Mixed<br />

Integer Programming models are derivate both in Polar as in Cartesian<br />

coordinates systems. Results compare both formulations with the original OPF<br />

model.<br />

3 - Global and Local Approaches for Large-scale Securityconstrained<br />

Optimal Power Flow<br />

Dzung Phan, Research Staff Member, IBM T.J. Watson Research<br />

Center, 1101 Kitchawan Road, Yorktown Heights, NY, 10598,<br />

United States of America, phandu@us.ibm.com,<br />

Jayant Kalagnanam<br />

We present global and local methods for solving the security-constrained optimal<br />

power flow problem. We propose a class of global methods based on Lagrangian<br />

duality to solve the problem to optimality. For practical uses when dealing largescale<br />

instances, two decomposition algorithms based on Benders cut and ADMM<br />

are investigated. These schemes often generate solutions whose objective values<br />

are smaller than the conventional approach and are very close to the optimal<br />

points.<br />

4 - Optimization of Electrical Efficiency using Mixed<br />

AC/DC Distribution<br />

Stephen Frank, PhD Student, Electrical Engineering, Colorado<br />

School of Mines, 1500 Illinois St., Golden, CO, 80401, United<br />

States of America, stfrank@mymail.mines.edu, Steffen Rebennack,<br />

Pankaj (PK) Sen<br />

The majority of electrical loads and distributed generation sources in modern<br />

buildings require direct current (DC), but grid-level electricity generation,<br />

transmission, and distribution systems continue to use alternating current (AC). A<br />

significant amount of energy is lost due to AC/DC conversion. This presentation<br />

explores formulations and solution methods for the optimal design of mixed<br />

AC/DC distribution systems to minimize the losses due to AC/DC conversion.<br />

■ SD02<br />

02- West 102 A- CC<br />

2012 DAS Practice Award Presentations<br />

Sponsor: Decision Analysis<br />

Sponsored Session<br />

Chair: Gregory Parnell, United States Military Academy, West Point, NY,<br />

10996, United States of America, gregory.parnell@usma.edu<br />

1 - Catalyze Supports UK Ministry of Defence Training<br />

Rationalisation<br />

Carmen Carmona, Consultant, Catalyze, 1 The Old Diary,<br />

Bunstead Barns, Hursley, SO21 2LL, United Kingdom,<br />

CarmenCarmona@catalyze.co.uk, Patrick Warburton,<br />

Rex Mazonowicz<br />

Catalyze designed and implement a two level stakeholder socio-technical process<br />

aiming to consistently assess 24 possible options, using a mix of financial, socio<br />

and technical criteria. The process allowed the wider stakeholders and MOD<br />

scrutiny community to be convinced of the integrity of the decision consequences<br />

and engage MOD Experts from all three armed services. (Navy, Royal Air Force<br />

and Army)<br />

2 - AESA: Decision Analysis in Search for Safer Skies<br />

David Rios Insua, Professor on Statistics and Decision Sciences,<br />

Royal Academy of Sciences, Calle Valverde, 22, Madrid, Spain,<br />

david.rios@urjc.es, Pablo Hernandez-Coronado, Esperanza Herraiz,<br />

Jorge Valero, Veronica Elvira<br />

We describe the pioneering efforts of the Spanish Agency for Air Transportation<br />

Safety in using Decision Analysis within the State Safety Programme. We<br />

illustrate modeling issues in forecasting threats and their severities, identifying<br />

and communicating the most severe ones, allocating resources to mitigating<br />

them, and delivering safe sky policies in public-private partnership.


3 - Operations Analysis Workforce Development<br />

Capabilities Assessment<br />

William Nanry, Member, Group Technical Staff, Lockheed Martin<br />

Missiles and Fire Control, 1701 W. Marshall Drive, Grand Prairie,<br />

TX, 75265, United States of America, william.nanry@lmco.com,<br />

Steve Dininger<br />

To enhance operations analysis (OA), the Lockheed Martin OA Workforce<br />

Development Team assessed the value each OA capability / skill provides to<br />

anticipate needs, assess shortfalls, and articulate mission understanding to<br />

generate affordable and relevant solutions for decision-makers and end-users. A<br />

multi-attribute decision support exercise was conducted to identify those key<br />

critical OA capabilities / skills across Lockheed Martin.<br />

■ SD03<br />

03- West 102 B- CC<br />

Joint Session DAS/HAS: Decision Analytic Models<br />

in Healthcare<br />

Sponsor: Decision Analysis & Health Applications Society<br />

Sponsored Session<br />

Chair: Turgay Ayer, Assistant Professor, Georgia Institute of Technology,<br />

765 Ferst Drive, Atlanta, GA, 30332, United States of America,<br />

ayer@isye.gatech.edu<br />

1 - Monotone Policies in Dynamic Medical Treatment Planning<br />

Archis Ghate, University of Washington, Industrial and Systems<br />

Engineering, Seattle, WA, United States of America,<br />

archis@uw.edu<br />

A central problem in medicine requires physicians to choose dose levels that<br />

achieve adequate disease control while limiting adverse effects over a treatment<br />

course with multiple decision points. We propose a stylized stochastic dynamic<br />

programming formulation of this problem and prove the existence of a monotone<br />

optimal policy in which dose levels increase with disease severity. This result is<br />

illustrated using an example from cancer radiotherapy.<br />

2 - Optimizing Radiation Delivery Schedules for Gliomas<br />

Kevin Leder, Assistant Professor, University of Minnesota, 111<br />

Church St., Minneapolis, MN, 55455, United States of America,<br />

Kevin.Leder@me.umn.edu, Ken Pitter, Eric Holland,<br />

Franziska Michor<br />

We construct a model to study the response of gliomas to radiation therapy. In<br />

particular, we consider a model considering two distinct cell populations, a slow<br />

growing radio-resistant stem cell population and a faster growing radio-sensitive<br />

progenitor cell population. Cells dynamically switch back and forth between these<br />

two states in response to radiation doses. In the context of this model we identify<br />

near optimal dosing schedules, and compare their performance to standard<br />

therapies.<br />

3 - Evaluating the Impact of Performance Goals on Emergency<br />

Medical Service Dispatching Decisions<br />

Laura McLay, Virginia Commonwealth University, Statistics &<br />

Operations Research, 1015 Floyd Ave., Box 843083, Richmond,<br />

VA, 23284, United States of America, lamclay@vcu.edu,<br />

Maria Mayorga<br />

Emergency medical services measure performance based on response time<br />

thresholds, i.e., the proportion of calls responded to within a fixed timeframe. The<br />

ultimate goal of emergency medical services is to save lives, which suggests that it<br />

might be worthwhile to consider using performance measures more closely tied to<br />

patient outcomes. This paper examines how different response time threshold<br />

performance goals impact patient survival rates in the context of emergency<br />

medical dispatch.<br />

4 - Improving Access to Community-based Chronic Care through<br />

Improved Capacity Allocation<br />

Tingting Jiang, Student, Northwestern University, 2145 Sheridan<br />

Road Room C210, Evanston, IL, 60208, United States of America,<br />

tingting-jiang@northwestern.edu, Seyed Iravani, Sarang Deo,<br />

Karen Smilowitz<br />

We study a model of community-based healthcare for chronic diseases. Patients<br />

periodically access the healthcare system, influencing their disease progression<br />

and health outcomes. The provider’s goal is to maximize community-wide health<br />

outcomes, subject to capacity constraint. We investigate how the provider can<br />

improve her objective through better operational decisions.<br />

INFORMS Phoenix – 2012<br />

131<br />

■ SD04<br />

SD04<br />

04- West 102 C- CC<br />

Scoring Rules, Probability Assessment, and Bias<br />

Sponsor: Decision Analysis<br />

Sponsored Session<br />

Chair: Robert Hammond, The University of Texas at Austin,<br />

1 University Station, Austin, TX, United States of America,<br />

robertkh@gmail.com<br />

Co-Chair: Eric Bickel, Assistant Professor, The University of Texas at<br />

Austin, 1 University Station, C2200, Austin, TX,<br />

United States of America, ebickel@mail.utexas.edu<br />

1 - Lossed in Translation: Adjusted Scoring Rules to Recover<br />

Subjective Beliefs from Loss-Averse Experts<br />

Asa Palley, The Fuqua School of Business, Duke University,<br />

100 Fuqua Drive, Box 90120, Durham, NC, 27708,<br />

United States of America, abp12@duke.edu, Theo Offerman<br />

We apply a prospect theory model of risk preferences to examine the incentives of<br />

an expert under an asymmetric quadratic scoring rule. We use these results to<br />

develop the L-adjusted scoring rule, a modified quadratic rule that corrects these<br />

distortions and allows for the recovery of an accurate estimate of probabilistic<br />

beliefs. Finally, we conduct an experiment that demonstrates the effectiveness of<br />

this modification in eliciting truthful beliefs and eliminating conservative baseline<br />

reports.<br />

2 - Gender and Performance in Risky Situations<br />

Susan Fisk, PhD Candidate, Stanford University, Sociology<br />

Deparment, Building 120, Room 031, Stanford, CA, 94305,<br />

United States of America, sfisk@stanford.edu, Ross Shachter<br />

We explore the role gender plays in risk-taking, using data from a large<br />

undergraduate decision analysis class in which the midterm uses a probabilistic<br />

scoring rule but the final exam does not. Controlling for academic major, we find<br />

that women take fewer risks than men, confirming established research on<br />

gender and risk-taking. In addition, we find that women perform worse on exams<br />

when their grade is determined by the scoring rule instead of conventional<br />

grading methods.<br />

3 - Strictly Proper Mechanisms with Cooperating Players<br />

Ross Shachter, Associate Professor, Stanford University,<br />

Department of Management Science and Eng, Huang Engineering<br />

Center, Stanford, CA, 94305, United States of America,<br />

shachter@stanford.edu, SangIn Chun<br />

Prediction markets provide an efficient means to assess uncertain quantities from<br />

forecasters. Although traditional and competitive strictly proper scoring rules<br />

have been shown to incentivize forecasters to provide accurate probabilistic<br />

forecasts acting alone, when forecasters with different beliefs can cooperate, these<br />

mechanisms instead discourage honest reports. Nonetheless, we show conditions<br />

under which the decision maker can confidently apply the assessed probabilities.<br />

4 - Scoring Rules and the Measurement of Uncertainty<br />

Eric Bickel, Assistant Professor, The University of Texas at Austin,<br />

1 University Station, C2200, Austin, TX, United States of America,<br />

ebickel@mail.utexas.edu<br />

Strictly proper scoring rules (SPSRs) continue to play an important role in<br />

probability assessment. While many such rules have been developed, relatively<br />

little guidance exists as to which rule is the most appropriate. All SPSRs reward<br />

calibration. In this presentation, we focus on how differing rules reward<br />

sharpness and argue that log scoring is the only rule that is consistent with<br />

entropy as a measure of uncertainty.


SD05<br />

■ SD05<br />

05- West 103 A- CC<br />

Process Engineering<br />

Contributed Session<br />

Chair: Raed Naebulharam, Research Assistant, University of Wisconsin-<br />

Milwaukee, 3200 North Cramer St, EMS 280, Milwaukee, WI, 53211,<br />

United States of America, naebulh2@uwm.edu<br />

1 - Refinery Operation Decisions with the Consideration of the<br />

Price Fluctuations<br />

Ruoran Chen, PhD Student, Department of Industrial Engineering,<br />

Tsinghua University, Building ZJ14#0429A, Beijing, 100084,<br />

China, crr11@mails.tsinghua.edu.cn, Simin Huang, Ruwen Qin<br />

Refineries face the price fluctuations in crude oil and products when making<br />

decisions in procurement and production. We first construct an LP model for a<br />

refinery to maximize the total profit. Then the model is extended to a large-scale<br />

multi-period stochastic dynamic programming to optimize the procurement,<br />

inventory and refinery decisions. A numerical method is developed to solve the<br />

problem. Numerical experiments are set up to demonstrate the importance of<br />

integrating these decisions.<br />

2 - Integrated Maintenance and Production Scheduling under<br />

Deteriorating Machine Conditions<br />

Maliheh Aramon Bajestani, PhD Candidate, University of Toronto,<br />

Mechanical & Industrial Engineering Dept, Unit 804, 141<br />

Davisville Ave., Toronto, ON, M4S 1G7, Canada,<br />

maramon@mie.utoronto.ca, J. Christopher Beck, Dragan Banjevic<br />

We address the problem of maintenance and production scheduling in a<br />

deteriorating multi-stage, multi-product system with random demand. Exploiting<br />

machine condition information, we formulate a Markov decision process model<br />

to determine the maintenance plan over the long term and then formulate an<br />

integer programming model to find the maintenance and the production schedule<br />

in the current period. Our results demonstrate that the planned schedule is very<br />

close to the actual schedule that is executed.<br />

3 - Hub and Chain: A Variance-based Method for Designing<br />

Process Flexibility<br />

Zhiguang Han, PhD Student, Nanyang Business School, Nanyang<br />

Technological University, 50 Nanyang Avenue, Singapore, 639798,<br />

Singapore, hanz0007@ntu.edu.sg, Shaoxiang Chen, Geoffrey Chua<br />

We study the process flexibility design issue. To our best knowledge, the demand<br />

variance has been generally ignored in the literature. We investigate the effect of<br />

demand variance and present a simple variance-based method to construct good<br />

flexible structures that link several small chains together in a hub. Our numerical<br />

tests show that our method performs better than existing methods such as<br />

chaining and constraint sampling, in both computational time and structure<br />

quality.<br />

4 - Bernoulli Serial Lines with Deteriorating Product Quality:<br />

Evaluation & System-theoretic Properties<br />

Raed Naebulharam, Research Assistant, University of Wisconsin-<br />

Milwaukee, 3200 North Cramer St., EMS 280, Milwaukee, WI,<br />

53211, United States of America, naebulh2@uwm.edu,<br />

Liang Zhang<br />

This paper assumes that the probability that each unfinished part is of good<br />

quality is a decreasing function of its residence time in the preceding buffer. Then,<br />

in serial production lines with machines having Bernoulli reliability model,<br />

closed-form formulas for performance evaluation in the two-machine line case<br />

were derived, and an aggregation-based procedure to approximate the<br />

performance measures in M > 2-machine lines was developed. Monotonicity<br />

properties were also studied.<br />

5 - Demand Forecasting in Revenue Management under Availability<br />

Constraints<br />

Shadi Sharif Azadeh, Polytechnique Montreal, 2900 Boulevard<br />

Edouard-Montpetit Montre, Montreal, QC, Canada,<br />

shadi.sharifazadeh@polymtl.ca, Gilles Savard<br />

We investigate the problem of demand forecasting in transportation. Seats are<br />

limited therefore, transportation companies continue to accept reservations in a<br />

fare class until the booking limit is reached. We propose an optimization model<br />

which takes availability constraints into account in order to have more accurate<br />

insight about demand behavior.<br />

INFORMS Phoenix – 2012<br />

132<br />

■ SD06<br />

06- West 103 B- CC<br />

Metamodeling Techniques for<br />

Simulation Optimization<br />

Sponsor: Simulation<br />

Sponsored Session<br />

Chair: Sujin Kim, Assistant Professor, National University of Singapore,<br />

1 Engineering Drive 2, Singapore, 117576, Singapore, iseks@nus.edu.sg<br />

1 - A New Framework for Combining Global and Local Surrogates<br />

in Black-box Optimization<br />

Yibo Ji, National University of Singapore, Kent Ridge Crescent,<br />

Singapore, 119260 SK, Singapore, jiyibo@nus.edu.sg, Wendy Xu,<br />

Myun-Seok Cheon, Sujin Kim<br />

We propose a new framework for solving computationally expensive optimization<br />

problems, where neither their closed-forms nor derivatives are available. We first<br />

build a global metamodel to identify the promising area, and then conduct a local<br />

search to ensure local optimality. One of the key performance factors is how we<br />

balance the two procedures. The framework is designed to accommodate various<br />

types of global and local search methods. Numerical studies demonstrate the<br />

feasibility of our work.<br />

2 - Enhancing Stochastic Kriging Metamodels with<br />

Gradient Estimators<br />

Barry Nelson, Professor, Northwestern University, 2145 Sheridan<br />

Road, Department of IEMS, Evanston, IL, 60208-311,<br />

United States of America, nelsonb@northwestern.edu, Xi Chen,<br />

Bruce Ankenman<br />

Stochastic kriging is a metamodeling technique for effectively representing the<br />

mean response surface implied by a stochastic simulation. We show that<br />

incorporating gradient estimates into stochastic kriging tends to significantly<br />

improve surface prediction. We also evaluate the properties of infinitesimal<br />

perturbation analysis and likelihood ratio gradient estimators when incorporated<br />

into stochastic kriging.<br />

3 - Augmenting Simulation Metamodels with Direct<br />

Gradient Estimates<br />

Huashuai Qu, University of Maryland, College Park, MD,<br />

United States of America, huashuai@math.umd.edu, Michael Fu<br />

Traditional metamodel-based optimization methods assume experiment data<br />

collected consist of performance measurements only. However, in many settings<br />

found in stochastic simulation, direct gradient estimates are available. We<br />

investigate techniques that augment existing regression and stochastic kriging<br />

models to incorporate additional gradient information. The augmented models<br />

are shown to be compelling compared to existing models, in the sense of<br />

improved accuracy or reducing simulation cost.<br />

■ SD07<br />

07- West 104 A- CC<br />

Machine Learning I<br />

Sponsor: Data Mining<br />

Sponsored Session<br />

Chair: Cynthia Rudin, Assistant Professor, Massachusetts Institute of<br />

Technology, 77 Massachusetts Avenue, Cambridge, MA,<br />

United States of America, rudin@mit.edu<br />

1 - Using Latent Semantic Analysis and Support Vector Machine in<br />

Multi-level Polarity Sentiment Analysis<br />

Yilu Zhou, Assistant Professor, George Washington University,<br />

2201 G St NW Suite 515, Washington, DC, 20052,<br />

United States of America, yzhou@gwu.edu<br />

We propose a multi-level polarity sentiment analysis framework that utilizes a<br />

Natural Language Processing technique: Latent Semantic Analysis (LSA) to<br />

reduce feature dimensionality and a multi-classifier SVM to detect sentiment<br />

level. We conducted a series of experiments to estimate the optimal kernel<br />

parameters and the dimension of features. The results shows that LSA can<br />

effectively reduce term feature dimensions and the optimal dimension and kernel<br />

parameters can boost the performance.<br />

2 - Machine Learning Methods from Statistical Physics<br />

Mohsen Bayati, Stanford University, Stanford, CA,<br />

United States of America, bayati@stanford.edu, Andrea Montanari<br />

We present results on approximate message passing (AMP) that is an iterative<br />

algorithm for high-dimensional data analysis and is inspired by statistical physics<br />

ideas.


3 - A Comparison of Criteria for the Smoothing Parameter<br />

Selection in Partial Spline with Change Points<br />

Sung Won Han, Fellow, Hoffmann-La Roche Inc.,<br />

340 Kingsland St., Nutley, NJ, United States of America,<br />

sung_won.han@roche.com, Hua Zhong<br />

In many applications such as bio-informatics, the estimation of the starting and<br />

ending points of drop-down in the longitudinal data is one of the key problems.<br />

We used a partial spline model based on the reproducing kernel Hilbert spacebased<br />

spline and multiple change points. Since the existing criteria for the<br />

smoothing parameter selection in partial spline with change points are not proper,<br />

we propose simple and better criteria to estimate change points.<br />

■ SD08<br />

08- West 104 B- CC<br />

Joint Session SPPSN/MAS: Humanitarian Logistics<br />

and Disaster Response I<br />

Sponsor: Public Programs, Service and Needs & Military<br />

Applications<br />

Sponsored Session<br />

Chair: Jarrod Goentzel, Massachusetts Institute of Technology,<br />

Room E38-650, 77 Massachusetts Ave., Cambridge, MA, 02139,<br />

United States of America, goentzel@mit.edu<br />

1 - Airport Congestion During Relief Operations<br />

Mike Veatch, Gordon College, Department of Mathematics,<br />

255 Grapevine Rd, Wenham, MA, 01984, United States of<br />

America, Mike.Veatch@gordon.edu, Jarrod Goentzel<br />

Scheduling the airlift of relief supplies into a damaged or small airport during a<br />

crisis is a major challenge. Adapting to the local conditions and coordinating the<br />

many international donors and airlift providers is complex. Alternative scheduling<br />

methods are proposed and assessed using queueing models with data from the<br />

Haiti earthquake.<br />

2 - Managing Bottlenecks in Port and Overland Transport Networks<br />

for Food Aid<br />

Mallory Soldner, Georgia Institute of Technology, Atlanta, GA,<br />

United States of America, msoldner@gatech.edu, Jarrod Goentzel,<br />

Ozlem Ergun<br />

Based on experience with WFP in East Africa, port bottlenecks can restrict the<br />

flow of life saving food aid. We introduce a canonical framework for building<br />

acyclic queuing networks to model port and overland transportation networks.<br />

Steady state equations and approximations are used to define cost and time<br />

bottlenecks. We classify how these bottlenecks shift in the network depending on<br />

parameters and decisions. Finally, we consider how adding capacity to the<br />

network impacts efficiency.<br />

3 - Modeling and Analyzing Supply Chain Viability<br />

Mariah Magagnotti, Graduate Research Assistant, Clemson<br />

University, 110 Freeman Hall, Clemson, SC, 29634,<br />

United States of America, mariahm@clemson.edu, Scott Mason<br />

The supply chain literature reveals many performance measures focused on<br />

localized costs and/or throughput. A holistic view is more appropriate when a<br />

supply chain is disrupted due to an emergency or disaster, as many of the key<br />

decisions to be made are interdependent. We present a capacitated, multicommodity<br />

flow model under two competing objectives and demonstrate how<br />

viability-based decision making can impact both performance measures of<br />

interest.<br />

4 - Scheduling and Routing for a Bus-based Evacuation with<br />

Constant Evacuee Arrival Rate<br />

Victor Pereira, PhD Student, Virginia Tech, Department of<br />

Industrial and Systems Eng., 250 Durham Hall, Blacksburg, VA,<br />

24061-0118, United States of America, vpereira@vt.edu,<br />

Douglas Bish<br />

In this presentation, a variant of the vehicle routing problem for bus-based<br />

evacuation planning is introduced. The problem assumes that evacuees arrive at a<br />

constant rate, and seeks a schedule of pick-ups and the routes for a fleet of buses<br />

that minimizes their waiting time at various pick-up locations. In addition, the<br />

effect of service level over the waiting time is explored and upper and lower<br />

bounds on the fleet size and an upper bound on the number of arc traversals per<br />

bus are proposed.<br />

INFORMS Phoenix – 2012<br />

133<br />

■ SD09<br />

SD09<br />

09- West 105 A- CC<br />

AHP/ANP Applications<br />

Sponsor: Multiple Criteria Decision Making<br />

Sponsored Session<br />

Chair: Birsen Karpak, Professor of Management, Youngstown State<br />

University, One University Plaza, WCBA 3303, Youngstown, OH,<br />

44555, United States of America, bkarpak@ysu.edu<br />

1 - Integrating Multicriteria Analysis and Geographic Information<br />

Systems: An Application of Spatial ANP<br />

Valentina Ferretti, PhD, Politecnico di Torino, Corso Castelfidardo<br />

30/A, Torino, 10138, Italy, valentina.ferretti@polito.it,<br />

Giulio Mondini<br />

Spatial Multicriteria Evaluations are rapidly gaining traction for planning and<br />

policy-making as useful tools to make decision processes effective and reliable.<br />

The contribution proposes a Spatial Multicriteria approach based on the<br />

integration of Geographic Information Systems and the Analytic Network Process<br />

for the development of a land suitability analysis in the context of undesirable<br />

facilities location problems. The integrated approach is able to cope with complex<br />

decision problems.<br />

2 - Evaluating the Performance of Brazilian Financial Managers<br />

with the AHP<br />

Luiz F. Autran M. Gomes, Professor, Ibmec/RJ, Av. Presidente<br />

Wilson, 118, Room 1110, Rio de Janeiro, 20030020, Brazil,<br />

autran@ibmecrj.br, Renata Andrade<br />

The key objective of this paper is to show, through a case study, how managers<br />

working for a financial organization in Brazil were evaluated in their performance<br />

by using the AHP method. Based on the success of the study the organization has<br />

decided that the AHP method should definitely be considered as the analytical<br />

tool to be utilized in their future performance evaluation processes.<br />

3 - Evaluation of Emergency Distribution Centers in Istanbul<br />

Ozay Ozaydin, Research Assistant, Dogus University, Zeamet S.<br />

No:21, Acibadem, Istanbul, 34722, Turkey, oozaydin@dogus.edu.tr,<br />

Ilker Topcu<br />

In disaster management, logistics play a major role and distribution centers are<br />

namely in the center of this role. As Istanbul has a highly dynamic environment,<br />

the previous studies on location of distribution centers can rapidly become<br />

obsolete and even infeasable. Using Geographical Information Systems (GIS) as<br />

main data input for an AHP model, this study not only evaluates the current<br />

situation but also proposes a dynamic system to make additional research and<br />

update process more manageable.<br />

4 - Cloud Computing Vendor Selection for the City of Pittsburgh<br />

Enrique Mu, MBA Program Director, Carlow University,<br />

3333 Fifth Avenue, Pittsburgh, PA, 15213, United States of<br />

America, ENRIQUEM@pitt.edu, Howard Stern<br />

Like many government agencies, the technology department at the City of<br />

Pittsburgh has had to deal with shrinking budgets and increased demands for<br />

state-of-the-art technology like cloud computing. The City employed the Analytic<br />

Hierarchy Process (AHP) methodology to select the most innovative and costeffective<br />

cloud computing solution provider. Lessons learned and issues with<br />

respect to this collaboration and public group decision-making in the context of<br />

new technology will be discussed.


SD10<br />

■ SD10<br />

10- West 105 B- CC<br />

Stochastic Programming with Discrete<br />

Random Variables<br />

Sponsor: Optimization/Stochastic Programming<br />

Sponsored Session<br />

Chair: Anh Ninh, Rutgers Center of Operations Research,<br />

Rutgers University, Piscataway, United States of America,<br />

ninhtuananh@gmail.com<br />

1 - Probabilistic Constrained Stochastic Programming with<br />

Independent Discrete Random Variables<br />

Kunikazu Yoda, PhD Candidate, Rutgers University, 640<br />

Bartholomew Rd, Piscataway, NJ, 08854-8003, United States of<br />

America, kyoda@rutcor.rutgers.edu, Andras Prekopa<br />

We consider the probabilistic constrained stochastic programming problem where<br />

the random right-hand side vector of independent components follows a discrete<br />

distribution with a finite support. The decision variables can be integers or real<br />

numbers. The problem is formulated by a mixed-integer linear programming with<br />

the concept of p-efficient points of a distribution. We present some techniques to<br />

improve the performance of the solution with MILP solver software and show<br />

numerical examples.<br />

2 - Numerical Solution of Large Scale Moment Problem in Case of<br />

Piecewise Higher Order Convex Objective<br />

Anh Ninh, Rutgers Center of Operations Research,<br />

Rutgers University, Piscataway, United States of America,<br />

ninhtuananh@gmail.com, Gabriela Alexe, Andras Prekopa<br />

We propose efficient numerical solution for the (continuous) power moment<br />

problem where the objective function is piecewise higher order convex. The<br />

solution goes through the solution of discrete moment problems with<br />

Vandermonde matrices in the equality constraints. Problems with up to 30<br />

moments can efficiently be solved but we can go higher in special cases.<br />

Numerical results will be reported.<br />

3 - Solution of the Univariate Discrete Moment Problem for New<br />

Classes of Functions<br />

Mariya Naumova, RUTCOR, Rutgers University, 640 Bartholomew<br />

Rd, Piscataway, NJ, 08854, United States of America,<br />

mnaumova@rci.rutgers.edu<br />

We characterize the dual feasible bases, in connection with univariate discrete<br />

moment problem for classes of objective function not dealt with until now. The<br />

new classes include, e.g., step functions with finite number of values. Applications<br />

will be mentioned to engineering design and finance.<br />

■ SD11<br />

11- West 105 C- CC<br />

Models in Robust Optimization<br />

Contributed Session<br />

Chair: Andreas Thorsen, PhD Candidate, Industrial Engineering and<br />

Operations Research, Pennsylvania State University, 310 Leonhard<br />

Building, University Park, PA, 16802, United States of America,<br />

aht105@psu.edu<br />

1 - Robust Optimization and Uncertain Prices in an Oil Refinery<br />

Supply Chain<br />

Jens Bengtsson, School of Economics and Business, Norwegian<br />

University of Life Sciences, P.O. Box 5003, Aas, Norway,<br />

jens.bengtsson@umb.no, Patrik Flisberg, Mikael Ronnqvist<br />

Uncertain prices of crude oil and refinery products may seriously affect the<br />

profitability of the refinery value chain. In this project we analyze the oil refinery<br />

planning problem using robust optimization in order to handle uncertainties in<br />

prices and to determine robust plans. The uncertainties can be described using<br />

historical and/or forecasted data in a flexible model.<br />

2 - Distributionally Robust Convex Optimization<br />

Wolfram Wiesemann, Imperial College London, 180 Queen’s Gate,<br />

London, United Kingdom, wwiesema@imperial.ac.uk,<br />

Melvyn Sim, Daniel Kuhn<br />

Distributionally robust optimization studies stochastic programs whose uncertain<br />

parameters follow a distribution that is itself uncertain. The distribution is only<br />

known to belong to an ambiguity set defined in terms of statistical or structural<br />

properties, and the goal is to hedge against the worst-case distribution within the<br />

ambiguity set. In this talk we present several distributionally robust optimization<br />

problems that admit polynomial-time solvable reformulations or approximations.<br />

INFORMS Phoenix – 2012<br />

134<br />

3 - The Robust Model for City Logistic Terminal Location<br />

Afrooz Ansaripour, University of Oklahoma, School of Industrial<br />

Engineering, Norman, OK, 73072, United States of America,<br />

afrooz.ansaripour@ou.edu, Theodore Trafalis,<br />

Mostafa Badakhshian<br />

The concept of logistic terminals has been presented to help cities reduce the total<br />

number of urban trips and negative impacts of transportation. This paper aims to<br />

apply robust optimization in the city logistic terminal location problem. The main<br />

goal is to minimize the transportation volume between the terminals considering<br />

uncertainty. The indicators include the flow and distances between terminals and<br />

also the weight of each flow. Preliminary computational results will be presented.<br />

4 - Robust Optimization Models for Military Airlift under<br />

Demand Uncertainty<br />

Andreas Thorsen, PhD Candidate Industrial Engineering and<br />

Operations Research, Pennsylvania State University, 310 Leonhard<br />

Building, University Park, PA, 16802, United States of America,<br />

aht105@psu.edu, Tao Yao<br />

The military airlift problem involves allocating cargo and passenger demands to<br />

aircraft and determining routes in order to achieve cost goals such as reducing<br />

overall cost and fuel consumption. Using robust optimization, we study the robust<br />

military airlift problem under demand uncertainty and present several mixedinteger<br />

program formulations including (static RO, two-stage RO, and multi-stage<br />

RO). We present results using data from the US military and examine the<br />

cost/robustness tradeoffs.<br />

5 - Estimating the Violation of the KKT Conditions<br />

Delphine Mico-Umutesi, University of Florida, 358 Little Hall,<br />

Gainesville, FL, 32611, United States of America, delmico@ufl.edu,<br />

William Hager<br />

Given x, not necessarily a local minimizer of an optimization problem, we<br />

propose a quantitative way of estimating how close x is to a solution of the KKT<br />

conditions. This estimate of the distance to a KKT point is the solution of a nonconvex<br />

optimization problem. We show how to solve this problem using an<br />

Active Set Algorithm (ASA) .<br />

■ SD12<br />

12- West 106 A- CC<br />

Advances in Integer Programming<br />

Sponsor: Optimization/Integer Programming<br />

Sponsored Session<br />

Chair: James Ostrowski, University of Tennessee, 1425 S Stadium Dr,<br />

Knoxville, TN, 37996, United States of America, jostrows@utk.edu<br />

1 - On Linear Programming Formulations of the TSP Polytope<br />

Sebastian Pokutta, Friedrich-Alexander-Universitat Erlangen-<br />

Nürnberg, Cauerstrasse 11, Erlangen, 91058, Germany,<br />

sebastian.pokutta@me.com, Serge Massar, Hans Raj Tiwary,<br />

Ronald de Wolf, Samuel Fiorini<br />

We solve a 20-year old problem posed by M. Yannakakis and prove that there<br />

exists no polynomial-size linear program (LP) whose associated polytope projects<br />

to the traveling salesman polytope, even if the LP is not required to be symmetric.<br />

Moreover, we prove that this holds also for the maximum cut problem and the<br />

stable set problem. These results follow from a new connection that we make<br />

between one-way quantum communication protocols and semidefinite<br />

programming reformulations of LPs.<br />

2 - Solution Approaches for the Cutting Stock Problem with<br />

Setup Cost<br />

Ali Ekici, University of Houston, Department of Industrial<br />

Engineering, Houston, TX, United States of America,<br />

aekici@central.uh.edu, Azadeh Mobasher<br />

In this research, we study the Cutting Stock Problem with Setup Cost (CSP-S). In<br />

CSP-S, unlike traditional Cutting Stock Problem (CSP), we have separate cost<br />

factors for the number of setups and material usage, and the objective is to<br />

minimize total production cost including both material and setup costs while<br />

satisfying demand. We propose two local search algorithms and a column<br />

generation algorithm, and test these algorithms on a set of instances from the<br />

literature.


3 - Partial Objective Function Inequalities for the Multi-Item<br />

Capacitated Lot-Sizing Problem (MCLSP)<br />

Esra Buyuktahtakin, Assistant Professor, Wichita State University,<br />

IME Department, Wichita, KS, United States of America,<br />

esra.b@wichita.edu, J. Cole Smith, Joseph Hartman<br />

We derive valid bounds on the partial objective function of the MCLSP<br />

formulation via dynamic programming and integer programming techniques. We<br />

then develop algorithms for strengthening these valid inequalities by back-lifting<br />

binary and continuous variables. These inequalities are utilized in a cutting-plane<br />

strategy, in which we perturb the partial objective function coefficients for the<br />

MCLSP polytope. We present computational experiments with the proposed valid<br />

inequalities.<br />

4 - Optimizing the Layout of Proportional Symbol Maps<br />

Tallys Yunes, Department of Management Science, University of<br />

Miami, Coral Gables, FL, 33124-8237, United States of America,<br />

tallys@bus.miami.edu, Guilherme Kunigami, Pedro de Rezende,<br />

Cid de Souza<br />

Proportional symbol maps help cartographers and geo-scientists visualize geopositioned<br />

data, e.g. population and earthquakes. At specific locations, symbols<br />

are placed and scaled to make their areas proportional to the magnitude of the<br />

data. We present a novel IP model to draw opaque disks on a map while<br />

maximizing the visible border of all disks. We implement new decompositions and<br />

facets in a branch-and-cut algorithm, and are the first to optimally solve real<br />

instances of this problem.<br />

■ SD13<br />

13- West 106 B- CC<br />

Efficient Optimization Algorithms and Their<br />

Recent Applications<br />

Sponsor: Optimization/Linear Programming and Complementarity<br />

Sponsored Session<br />

Chair: Hongchao Zhang, Louisiana State Univeristy, Department of<br />

Mathematics, Baton Rouge, United States of America,<br />

hozhang@math.lsu.edu<br />

1 - Minimizing Rational Functions by Exact Jacobian SDP<br />

Relaxation<br />

Li Wang, University of Southern California, 3715 McClintock Ave.,<br />

RM 236, Los Angeles, CA, 90089, United States of America,<br />

Wang40@usc.edu, Feng Guo<br />

We study the optimization problem of minimizing a rational function. We<br />

reformulate this problem as polynomial optimization by the technique of<br />

homogenization. These two problems are shown to be equivalent under some<br />

general conditions. The exact Jacobian SDP relaxation method proposed by Nie is<br />

used to solve the resulting polynomial optimization.<br />

2 - Mini-batch Stochastic Approximation Methods for Constrained<br />

Nonconvex Stochastic Programming<br />

Saeed Ghadimi, University of Florida, P.O. Box 210020,<br />

Gainesville, FL, 32611, United States of America,<br />

sghadimi@ufl.edu, Hongchao Zhang, Guanghui Lan<br />

We present a randomized mini-batch stochastic approximation method for solving<br />

constrained nonconvex stochastic programming problems. Complexity analysis of<br />

finding an approximate stationary point of this kind of problems is provided.<br />

Some computational results are also presented to show practical performance of<br />

the proposed algorithm.<br />

3 - A Quadratic C0 Interior Penalty Method for the Displacement<br />

Obstacle Problem of Clamped Plates<br />

Yi Zhang, Graduate Student, Louisiana State University, 103<br />

Lockett Hall, Department of Mathematics, LSU, Baton Rouge, LA,<br />

70803, United States of America, yzhang24@math.lsu.edu,<br />

Li-yeng Sung, Hongchao Zhang, Susanne Brenner<br />

The displacement obstacle problem of clamped Kirchhoff plates is an example of a<br />

fourth order variational inequality whose numerical analysis is more subtle than<br />

that of second order variational inequalities. In this talk we will introduce C0<br />

interior penalty methods for this problem. Both error estimates and numerical<br />

results will be discussed. This is joint work with Susanne Brenner, Li-yeng Sung<br />

and Hongchao Zhang.<br />

INFORMS Phoenix – 2012<br />

135<br />

■ SD14<br />

14- West 106 C- CC<br />

United States Presidential Election Forecasting: Who<br />

Will Win the White House in 2012?<br />

Cluster: Public Policy<br />

Invited Session<br />

Chair: Sheldon Jacobson, Professor, University of Illinois, 201 N.<br />

Goodwin Avenue (MC258), Urbana, IL, 61801, United States of<br />

America, shj@illinois.edu<br />

1 - The Keys to the White House: Forecast for 2012<br />

Allan Lichtman, Distinguished Professor, Department of History,<br />

American University, Washington, DC, 20817,<br />

United States of America, lichtman@american.edu<br />

This paper will present the Keys to the White House and provide a forecast for the<br />

2012 presidential election. The Keys to the White House are a historically-based<br />

prediction system that retrospectively account for the popular-vote winners of<br />

every American presidential election from 1860 to 1980 and prospectively<br />

forecast well ahead of time the popular-vote winners of every presidential<br />

election from 1984 through 2012.<br />

2 - Modeling a Presidential Prediction Market<br />

Keith Chen, Yale School of Management, New Haven, CT,<br />

United States of America, Keith.chen@yale.edu, Edward Kaplan<br />

Using data from past Intrade US presidential prediction markets, we examined<br />

three alternative models for security prices, focusing on consistency with electoral<br />

college rules. We show that a simple diffusion model provides a good description<br />

of the overall distribution of electoral college votes, while an even simpler<br />

ranking model provides excellent predictions of the probability of winning the<br />

presidency. We derive implications for predicting the 2012 US presidential<br />

election.<br />

3 - The 2012 United States Presidential Election: And the<br />

Winner is?<br />

Sheldon Jacobson, Professor, University of Illinois, 201 N.<br />

Goodwin Avenue (MC258), Urbana, IL, 61801, United States of<br />

America, shj@illinois.edu, Edward Sewell, Steve Rigdon,<br />

Jason Sauppe<br />

Predict the number of electoral college votes for each candidatein the United<br />

States Presidential election can be a difficult task. This presentation discusses a<br />

Bayesian approach incorporating undecided voter effects into the analysis. A web<br />

site electionanalytics.cs.illinois.edu has been created for people to follow the<br />

resulting forecasts.<br />

■ SD15<br />

SD15<br />

15- West 202- CC<br />

Software Demonstration<br />

Invited Session<br />

1 - Lumina Decision Systems, Inc. - Introduction to Analytica,<br />

What it Does that Spreadsheets Can’t<br />

Surya Swamy, Consulting Decision Analyst, Lumina Decision<br />

Systems, 26010 Highland Way, Los Gatos, CA, 94117,<br />

United States of America, surya@lumina.com<br />

Experienced analysts prefer Analytica to spreadsheets because of its visual influence<br />

diagrams, Intelligent Arrays, fast Monte Carlo and scalability. Because it’s<br />

designed by expert modelers, it’s also an ideal tool for teaching students the art<br />

of effective modeling. View this software demo to see why users say that they<br />

can build, verify and analyze models in a quarter to half the time it takes with a<br />

spreadsheet.<br />

2 - Exploiting LINKS Simulations Web-based Resources for<br />

Maximum Teaching and Learning Impact<br />

Randall G. Chapman, Founder and President, LINKS Simulations,<br />

320 Forest Haven Drive, Winter Garden, FL, 34787,<br />

United States of America, chapman@LINKS-simulations.com<br />

How can an instructor teach effectively and efficiently with a large-scale, teambased,<br />

competitive supply chain management simulation? By exploiting the simulation’s<br />

web-based teaching and learning resources! This software demo<br />

explores web-based resources for supporting instructors and their students<br />

throughout LINKS simulation events.


SD16<br />

■ SD16<br />

16- West 207- CC<br />

Application of Kalman Filter in Traffic Management<br />

and Control<br />

Cluster: Tutorials<br />

Invited Session<br />

Chair: Hans van Lint, Associate Professor, Delft University of<br />

Technology, Stevinweg 1, Delft, 2628CN, Netherlands,<br />

j.w.c.vanlint@tudelft.nl<br />

1 - Application of Kalman Filter in Traffic Management and Control<br />

Hans van Lint, Associate Professor, Delft University of Technology,<br />

Stevinweg 1, Delft, 2628CN, Netherlands, j.w.c.vanlint@tudelft.nl<br />

In many areas of traffic management and control the variables that are of most<br />

interest are often the ones that are most difficult to measure and estimate. Take<br />

for example vehicular density (veh/km) and space-mean speed (km/h). A reliable<br />

real-time estimate of these quantities is critically important for real-time control<br />

of traffic networks. However, neither can be straightforwardly deduced from<br />

available sensor data. Similarly elusive quantities are origin-destination flows.<br />

These depict the amount of vehicles per hour planning to go from one place to<br />

another at a certain moment. Unless we literally know the origin and destination<br />

of \textit{all} vehicles on a traffic network, advanced estimation techniques are<br />

required to extract OD patterns from whatever available data and prior<br />

knowledge we have available. One intuitive and highly effective method to solve<br />

these types of problems (i.e. estimating a quantity x when all we have are<br />

observations y and prior knowledge about the process) is the Kalman Filter, first<br />

proposed by Rudolf Kalman in 1960. In this TutORial we explain with many<br />

examples how this technique can be applied in the domain of traffic management<br />

and control to solve real-world problems. We’ll see that Kalman filtering is a<br />

powerful technique, that works surprisingly well in many cases, but there are also<br />

clear limitations that relate to the many assumptions underlying its application.<br />

■ SD17<br />

17- West 208 B- CC<br />

Panel Discussion: Design Thinking for Creating a<br />

Capstone Course in Management Consulting<br />

Sponsor: INFORM-ED<br />

Sponsored Session<br />

Chair: Paul Szwed, Professor, U.S. Coast Guard Academy, Department<br />

of Management, 15 Mohegan Avenue, New London, CT, 06320,<br />

United States of America, Paul.S.Szwed@uscga.edu<br />

1 - Using Design Thinking to Create Meaningful<br />

Learning Experiences<br />

Moderator: Paul Szwed, Professor, U.S. Coast Guard Academy,<br />

Department of Management, 15 Mohegan Avenue, New London,<br />

CT, 06320, United States of America, Paul.S.Szwed@uscga.edu,<br />

Panelists: Laurel Goulet, Charles Coiro<br />

How do you go about developing a new course or improving an old one? One<br />

emerging method is to use concept and principles from design thinking. We had<br />

an award-winning capstone business consulting course that we knew was no<br />

longer getting us the desired results. Using design thinking concepts and<br />

principles, we conducted a “deep dive” on our course and developed an entirely<br />

new model. We will share the philosophies used and our experiences and lessons<br />

learned. Design thinking can be applied to a wide variety of courses or even<br />

modules in virtually any discipline.<br />

■ SD18<br />

18- West 208 A- CC<br />

Simulation for Transportation and Reliability<br />

Contributed Session<br />

Chair: Bex G. Thomas, Researcher, General Electric Global Research<br />

Center, 1 Research Center, Niskayuna, NY, 12309,<br />

United States of America, thomasb@ge.com<br />

1 - Incentives for Pedestrian Crossing Behavior with Vehicle<br />

Interactions under Unsignalized Conditions<br />

Hui Xi, The University of Arizona, 1127 E. James E, Rogers Way,<br />

Tucson, AZ, United States of America, huix@email.arizona.edu,<br />

Young-Jun Son<br />

Pedestrian crossing behavior under unsignalized conditions has been recognized<br />

as a main reason of pedestrian-vehicle crashes. This paper analyzes the incentives<br />

to prevent pedestrian jaywalking and their impact on pedestrian safety. By<br />

INFORMS Phoenix – 2012<br />

136<br />

considering heterogeneous behaviors of drivers and pedestrians as well as their<br />

interactions under various scenarios, we intend to identify the significant<br />

variables that help improve comfort and convenience as well as safety of<br />

pedestrian crossing.<br />

2 - Simulation of Container Truck-sharing Service (TSS): Reducing<br />

Empty Slots for Capacity Improvement<br />

Samsul Islam, University of Auckland, ISOM Department,<br />

12 Grafton Road, Auckland, New Zealand,<br />

misl086@aucklanduni.ac.nz, Tava Olsen<br />

Little attention has been paid by researchers to formulating strategies to resolve<br />

the issue of empty container-truck hauling, which decreases the system-wide<br />

truck transport capacity. The objective of this simulation paper is to perform and<br />

demonstrate scenario testing to compare three main strategies. These strategies<br />

include a dynamic truck sharing facility for an internet-based matching system to<br />

assign exporters to truckers to solve the empty-truck issue.<br />

3 - Modeling Life Cycle Performance of Asbestos Cement<br />

Water Mains<br />

Kent Kostuk, University of Saskatchewan, 57 Campus Drive,<br />

Saskatoon, SK, S7N 5A9, Canada, kent.kostuk@usask.ca,<br />

Gordon Sparks<br />

Municipalities in developed countries are facing a looming infrastructure crisis.<br />

Because of their visibility, roads and bridges are often the first infrastructure assets<br />

that come to mind. But buried infrastructure, such as water mains, are also<br />

decaying. To help quantify future costs and to identify ways to better manage and<br />

control these costs, a simulation model of an urban subdivision was developed.<br />

4 - Estimating Warranty Reserves for Photovoltaic Modules using<br />

Simulation Modeling and Analysis<br />

Bex G. Thomas, Researcher, General Electric Global Research<br />

Center, 1 Research Center, Niskayuna, NY, 12309,<br />

United States of America, thomasb@ge.com, Rajesh Tyagi<br />

GE Solar manufacturers and sources modules to be used within PV systems or<br />

resells it to end customers. The reliability and performance of these modules is<br />

guaranteed through product warranties and guarantees. We have developed a<br />

simulation based approach to estimate the warranty reserves over time that<br />

accounts for product specifications, manufacturing information, product<br />

reliability, product durability, warranty terms and associated costs. We highlight<br />

the advantages of our approach.<br />

■ SD19<br />

19- West 211 A- CC<br />

Joint Session Healthcare Logistics/SPPSN: Routing<br />

and Resource Allocation Applications in Disaster<br />

Relief<br />

Cluster: Healthcare Logistics & Public Programs, Service and Needs<br />

Invited Session<br />

Chair: Ashlea Bennett Milburn, Assistant Professor, University of<br />

Arkansas, 4207 Bell Engineering Center, Fayetteville, AR, United States<br />

of America, ashlea@uark.edu<br />

1 - Online Point of Distribution Location in Disaster Relief<br />

Ashlea Bennett Milburn, Assistant Professor, University of<br />

Arkansas, 4207 Bell Engineering Center, Fayetteville, AR,<br />

United States of America, ashlea@uark.edu, Chase Rainwater<br />

Information regarding affected populations, roads, buildings, and bridges becomes<br />

known on a rolling basis in the hours following a disaster. We develop online<br />

models that use real-time information regarding demand and infrastructure status<br />

to specify shelter locations and supply distribution points as a specific damage<br />

scenario is realized. Approximate solution approaches are employed to obtain<br />

good plans quickly. Computation results are presented for a New Madrid<br />

earthquake scenario.<br />

2 - Can Social Media Information Improve Disaster Relief<br />

Routing Plans?<br />

Emre Kirac, PhD Student, University of Arkansas, Department of<br />

Industrial Engineering, Fayetteville, AR, United States of America,<br />

ekirac@uark.edu, Clarence Wardell, Ashlea Bennett Milburn<br />

This research examines the impact of incorporating two distinct classes of<br />

information regarding the location and need of individuals impacted by a disaster<br />

when routing vehicles to deliver relief supplies: verified requests obtained<br />

through traditional means, and unverified requests obtained from social media.<br />

Competitive ratio analysis is performed for alternative decision approaches and<br />

computational results for a wide variety of disaster scenarios are presented.


3 - Developing a Dynamic Emergency Response Plan for a<br />

Post-earthquake Scenario<br />

Shuva Ghosh, Doctoral Candidate, Missouri University of Science<br />

and Technology, 223 Engineering Management Building, Rolla,<br />

MO, United States of America, sg2mb@mst.edu, Abhijit Gosavi<br />

An effective emergency response plan can play a vital role in minimizing risk to<br />

the people affected when an earthquake strikes. Emergency resources are<br />

generally stored in multiple responding centers. Emergency management<br />

personnel have to select an optimal combination of responding centers to respond<br />

effectively in a dynamically evolving situation. In this work, we integrate inputs<br />

from a so-called domino-effect analysis within a semi-Markov decision process to<br />

develop a response plan.<br />

■ SD20<br />

20- West 211 B- CC<br />

Optimization<br />

Sponsor: Telecommunications<br />

Sponsored Session<br />

Chair: Yavuz Gunalay, Bahcesehir University, Faculty of Economics and<br />

Admin Science, Besiktas, Istanbul, 34353, Turkey,<br />

yavuz.gunalay@bahcesehir.edu.tr<br />

1 - Using Cross-entropy for Solving the Stochastic Shortest<br />

Path Problem<br />

Adji Cisse, Texas Tech University, Box 43061, Lubbock TX 79409,<br />

United States of America, gnouma.cisse@ttu.edu, Timothy Matis<br />

In this presentation, we show how Cross-Entropy methods may be used to find<br />

the stochastic shortest path through a networks. At the core of this approach is<br />

the use of truncated saddlepoint approximations for the distribution of path<br />

lengths.<br />

2 - Uncertainty and Risk Analysis in Federal Cost<br />

Estimating Agencies<br />

Tomeka Williams, Senior Operations Research, Optimum<br />

Performance Solutions, 2486 Glengyle Drive, Vienna, VA, 22181,<br />

United States of America, tomeka.williams@gmail.com<br />

Uncertainty and risk analysis is a process that is unique, tailorable, and often<br />

times misunderstood within Federal Departments and Agencies. In working in<br />

three different cost estimating organizations, each has had several initiatives to<br />

bridge that gap. This session is intended to share the initiatives of each of these<br />

agencies, and practical tools that have been employed to ensure that uncertainty<br />

and risk analysis is included in Federal cost estimating products.<br />

3 - Probabilistic Interpretation for the Elasticity of Carried Load<br />

Revenue from the Erlang Loss Model<br />

William Massey, Professor, Princeton University, Sherrerd Hall<br />

Princeton University, Princeton, NJ, 08540,<br />

United States of America, wmassey@princeton.edu<br />

Suppose that we know the demand function for some telephone service as a<br />

function of the phone rate. If we model the number of busy channels as an Erlang<br />

loss model, then we have a formula for the carried load revenue rate as a function<br />

of this price rate. The explicit formula for the elasticity of this carried load rate can<br />

be expressed in terms of the elasticity of the corresponding offered load rate.<br />

■ SD21<br />

21- West 212 A- CC<br />

Clique Relaxations in Networks<br />

Sponsor: Optimization/Networks<br />

Sponsored Session<br />

Chair: Sergiy Butenko, Associate Professor, Texas A&M<br />

University,Industrial & Systems Engineering, 3131 TAMU, College<br />

Station, TX, 77843, United States of America, butenko@tamu.edu<br />

1 - New Developments in Finding Maximum 2-clubs in Graphs<br />

Foad Mahdavi Pajouh, Oklahoma State University, Industrial<br />

Engineering and Management, 322 Engineering North, Stillwater,<br />

Ok, 74075, United States of America, mahdavi@okstate.edu,<br />

Illya Hicks, Baski Balasundaram<br />

A k-club is an induced subgraph of diameter at most k which is a distance-based<br />

graph-theoretic generalization of a clique. The k-clubs can be used to model<br />

clusters in social networks, biological networks and internet graphs. This talk will<br />

outline the research challenges associated with k-club model because of its nonhereditary<br />

nature. New complexity results, theoretical results concerning the<br />

2-club polytope and preliminary numerical results will be presented.<br />

INFORMS Phoenix – 2012<br />

137<br />

2 - Degree-bounded Vertex Partitions<br />

John Arellano, Rice University, 6100 Main St., Houston, TX,<br />

77005-182, United States of America, jda2@rice.edu, Illya Hicks,<br />

Benjamin McClosky<br />

This paper studies degree-bounded vertex partitions, derives analogues for wellknown<br />

results on the chromatic number, and presents two algorithms for<br />

constructing degree-bounded vertex partitions. The first algorithm minimizes the<br />

number of partition classes. The second algorithm minimizes a weighted sum of<br />

the partition classes, where the weight of a partition class depends on the level of<br />

adjacency among its vertices.<br />

3 - Algorithms for Computing Optimal Clique Relaxation Structures<br />

that are Hereditary<br />

Chitra Balasubramaniam, 401 Stasney STreet, Apt 605,<br />

College Station, TX, 77840, United States of America,<br />

bcvaidyanath@neo.tamu.edu, Sergiy Butenko,<br />

Baski Balasundaram, Svyatoslav Trukhanov<br />

Heredity is a fundamental property of cliques that is in the core of some of the<br />

most successful combinatorial algorithms for the maximum clique problem. We<br />

use this observation to develop exact algorithms for computing maximum weight<br />

hereditary clique relaxation structures, such as s-plex and s-defective clique.<br />

■ SD22<br />

SD22<br />

22- West 212 B- CC<br />

Multilevel/Multistage Programming Applications<br />

Sponsor: Computing Society<br />

Sponsored Session<br />

Chair: Soheil Hemmati, PhD Student, University of Florida,<br />

406 Weil Hall, Gainesville, FL, 32603, United States of America,<br />

soheilmn@ufl.edu<br />

1 - An Algorithm for Solving Inverse Integer Programs<br />

Ted Ralphs, Associate Professor, Lehigh University, 200 West<br />

Packer Avenue, Bethlehem, PA, 18015, United States of America,<br />

ted@lehigh.edu, Aykut Bulut<br />

An inverse optimization problem is that of determining the smallest perturbation<br />

in a given objective function required to make a given solution optimal. In this<br />

talk, we introduce the inverse mixed integer linear programming problem, discuss<br />

its complexity, and propose a general algorithm for solving it. The relationship to<br />

bilevel programming will also be explored.<br />

2 - Selecting Land Preserves to Enable Species Migration<br />

Jorge Sefair, PhD Student, University of Florida, Department of<br />

Industrial & Systems Eng., Gainesville, FL, United States of<br />

America, j.sefair@ufl.edu, Miguel Acevedo, Robert Fletcher,<br />

. Cole Smith<br />

We consider a problem in which a species migrates randomly among a network of<br />

patches across some region. Development on these patches negatively influences<br />

the probability that an organism survives when it moves to a patch, and if a<br />

critical set of patches is selected for development, the survival of the species<br />

becomes threatened. Our research presents a three-stage optimization model for<br />

optimally protecting patches so that the worst-case impact of land development is<br />

mitigated.<br />

3 - A Parametric Integer Programming Algorithm for Bilevel Mixed<br />

Integer Programs<br />

Chris Ryan, University of Chicago, Chicago, IL, United States of<br />

America, chris.ryan@chicagobooth.edu, Matthias Koeppe,<br />

Maurice Queyranne<br />

We consider discrete bilevel optimization problems where the follower solves an<br />

integer program with a fixed number of variables. Using recent results in<br />

parametric integer programming, we present fixed-dimension polynomial time<br />

algorithms for pure and mixed integer bilevel problems.<br />

4 - Mixed-integer Bilevel Programming (MIBLP) Approach for<br />

Competitive Prioritized Set Covering Problem<br />

Soheil Hemmati, PhD Student, University of Florida, 406 Weil<br />

Hall, Gainesville, FL, 32603, United States of America,<br />

soheilmn@ufl.edu, J. Cole Smith<br />

In competitive set covering problem, which has several applications, including<br />

non-cooperative product introduction, two players aim to maximize their rewards<br />

by selecting sets of items to satisfy clauses. Each selected item incurs a cost to<br />

players and each clause is satisfied by the highest-priority selected item, yielding a<br />

reward for the player that introduced the item. We propose an MIBLP model with<br />

0-1 decision variables appear in both levels, and suggest an exact cutting-plane<br />

algorithm.


SD23<br />

■ SD23<br />

23- West 212 C- CC<br />

Panel Discussion: Managing a Career in OR<br />

Sponsor: CPMS, The Practice Section<br />

Sponsored Session<br />

Chair: Peter Bell, Professor, University of Western Ontario, Richard Ivey<br />

School of Business, London, ON, N6A 3K7, Canada, pbell@ivey.uwo.ca<br />

1 - CPMS Practitioners Offer Tips for Success<br />

Moderator: Peter Bell, Professor, University of Western Ontario,<br />

Richard Ivey School of Business, Londo, ON, N6A 3K7, Canada,<br />

pbell@ivey.uwo.ca, Panelists: Nicholas Nahas, Manoj K. Chari,<br />

Doug Samuleson, Vijay Mehrotra<br />

This panel will share why advanced analytics are needed today more than ever.<br />

Business leaders lack abilities to apply analytical tools and data structure to<br />

address their challenges. Despite years of talk about scorecards and metrics, most<br />

organizations still rely on gut feelings and experience for urgent critical matters.<br />

We can glean insights from data and guide them along innovative ways as<br />

analytical thinking can lead their organization into the future.<br />

■ SD24<br />

24- West 213 A- CC<br />

Empirical Research in Health Care Operation<br />

Sponsor: Health Applications Society<br />

Sponsored Session<br />

Chair: Lijie Song, MIT-Zaragoza International Logistics Program,<br />

Edificio N·yade, 5 C/ Bari 55, PLAZA, Zaragoza, 50197, Spain,<br />

lsong@zlc.edu.es<br />

1 - Physician Variation in Resource Utilization<br />

Jillian Berry, Doctoral Candidate, Harvard University,<br />

Soldiers Field, Boston, MA, 02478, United States of America,<br />

jberry@hbs.edu, Anita Tucker<br />

We study the variation in physician resource utilization in two academic<br />

Emergency Departments (ED) and how this variation is affect by resource<br />

availability.<br />

2 - Building Flexibility in US Healthcare Delivery through<br />

Medical Tourism<br />

Muer Yang, Assistant Professor, University of St. Thomas,<br />

1000 LaSalle Avenue, SCH 435, Minneapolis, MN, 55403,<br />

United States of America, yangmuer@stthomas.edu,<br />

Sameer Kumar<br />

Medical tourism is a large and growing phenomenon. In 2011 the medical<br />

tourism market was an estimated $20 billion, up from under $2 billion in 2005.<br />

The combination of cheap price and good medical care has caused an increasing<br />

number of Americans to choose medical tourism. We develop a mathematical<br />

model illustrated through discrete event simulation to show the impact of medical<br />

tourism on the cost and effectiveness of US healthcare delivery system.<br />

3 - Partially Flexible Operating Rooms<br />

Yann Ferrand, Assistant Professor, Clemson University,<br />

Department of Management, Sirrine Hall, Clemson, SC, 29634,<br />

United States of America, yferran@clemson.edu,<br />

Michael Magazine, Uday Rao<br />

When organizing the operating theatre and scheduling surgeries, hospitals face a<br />

trade-off between the need to be responsive to emergency cases and to conduct<br />

scheduled elective surgeries efficiently. We develop a simulation model to<br />

compare resource-allocation policies of complete flexibility, and of complete<br />

focus, and compare them to hybrid partial flexibility policies. We evaluate these<br />

policies on patient and provider outcome measures, including patient wait time<br />

and physician overtime.<br />

4 - Understanding Client Preferences for Preventive Care<br />

Lijie Song, MIT-Zaragoza International Logistics Program,<br />

Edificio Náyade, 5 C/ Bari 55, PLAZA, Zaragoza, 50197, Spain,<br />

lsong@zlc.edu.es, Vedat Verter, Beste Kucukyazici<br />

We studied a government-funded breast cancer screening program in Montreal,<br />

using stated preference discrete choice modeling as framework. This enables us to<br />

better understand the clients’ preference concerning facility attributes.<br />

Incorporating our findings in a simulation model, we are able to generate<br />

managerial insights on how to improve the participation to such programs.<br />

INFORMS Phoenix – 2012<br />

138<br />

■ SD25<br />

25- West 213 B- CC<br />

Chemotherapy Patient and Resource Management in<br />

Oncology Clinics<br />

Sponsor: Health Applications Society<br />

Sponsored Session<br />

Chair: Lewis Ntaimo, Associate Professor, Texas A&M University,<br />

3131, College Station, TX, 77843, United States of America,<br />

ntaimo@tamu.edu<br />

Co-Chair: Tanisha Cotton, Doctoral Candidate, Texas A&M University,<br />

3131 TAMU, College Station, TX, 77843, United States of America,<br />

tanbgreen05@neo.tamu.edu<br />

1 - Uncertainty in Chemotherapy Patient Scheduling<br />

Sara Shashaani, ISE PhD Student, Virginia Technical University,<br />

Blacksburg, VA, United States of America, sshashaa@vt.edu,<br />

Mark Lawley, Ayten Turkcan, Hong Wan<br />

Chemotherapy patient scheduling is a complex problem due to varying treatment<br />

lengths and nursing requirements, unpredictable same-day cancellations and<br />

unscheduled add-ons. Sensitivity analysis of uncertainties in the workflow is<br />

studied using a discrete-event simulation model to distinguish the stochastic<br />

elements that impose significant changes in the performance of the system when<br />

they encompass variability. Changes to the current deterministic scheduling<br />

model are proposed for flexibility.<br />

2 - Multi-criteria Nurse Assignment for Chemotherapy Patients in<br />

Oncology Clinics<br />

Ayten Turkcan, Northeastern University, Boston, MA,<br />

United States of America, A.Turkcan@neu.edu, Bohui Liang<br />

In oncology clinics, nurses with different skills are assigned to patients with<br />

different acuities to administer the chemotherapy. It is important to have a<br />

reasonable nurse workload for several reasons such as patient safety, quality of<br />

care, patient and staff satisfaction. We propose a multi-objective integer<br />

programming model with the objectives of balancing workload among nurses,<br />

and minimizing waiting time and overtime. We also propose a genetic algorithm<br />

to reduce the computation times.<br />

3 - Mean-risk Stochastic Optimization Approach for<br />

Chemotherapy Scheduling<br />

Tanisha Cotton, Doctoral Candidate, Texas A&M University, 3131<br />

TAMU, College Station, TX, 77843, United States of America,<br />

tanbgreen05@neo.tamu.edu, Michelle M. Alvarado,<br />

Eduardo Perez, Lewis Ntaimo<br />

Oncology clinics face tight resource and scheduling constraints due to increased<br />

demand, cyclic chemotherapy treatment plans, and complex and uncertain<br />

duration of treatments. This talk presents the model and results of using a risk<br />

neutral and risk averse two-stage stochastic optimization approach to efficiently<br />

schedule chemotherapy nurses, patients, and chairs based on a real oncology<br />

clinic.<br />

4 - Modeling and Simulation of an Oncology Clinic using DEVS<br />

Michelle M. Alvarado, PhD Student, Texas A&M University, 3131<br />

TAMU, College Station, TX, 77843, United States of America,<br />

michelle.mcgaha@gmail.com, Eduardo Perez, Tanisha Cotton,<br />

Lewis Ntaimo<br />

Scheduling of chemotherapy treatments is a difficult task due to the cyclic nature<br />

of the prescribed treatment regimen, variability of treatment lengths, and patient<br />

acuity levels. We present a discrete event system specification (DEVS) simulation<br />

model integrated with a stochastic mixed integer programming model (SMIP) to<br />

schedule and manage patients in an oncology clinic. Preliminary results are<br />

presented from the management perspective.


■ SD26<br />

26- North 221 A- CC<br />

Effective Decision-making in Pricing and<br />

Inventory Control<br />

Sponsor: Manufacturing & Service Oper Mgmt<br />

Sponsored Session<br />

Chair: Esma Gel, Arizona State University, Department of Industrial<br />

Engineering, Tempe, AZ, 85287, United States of America,<br />

esma.gel@asu.edu<br />

1 - A Comparison of Integrated Inventory/Outbound<br />

Dispatch Policies<br />

Sila Cetinkaya, Texas A&M University, College Station, TX,<br />

United States of America, sila@tamu.edu, Bo Wei<br />

We present an analytical comparison of alternative dispatch policies in the context<br />

of integrated inventory replenishment and outbound dispatch scheduling<br />

decisions. We prove that under the same expected replenishment cycle length and<br />

the same expected dispatch cycle length, quantity-based dispatching achieves the<br />

least inventory cost and waiting cost within one replenishment cycle, and, hence,<br />

it is superior to hybrid dispatching.<br />

2 - Leveraging Future Cost Reductions: A Dynamic Two-Sided<br />

Pricing Model<br />

Xiajun Amy Pan, University of Florida, United States of America,<br />

amypan@ufl.edu, Mei Lin<br />

Technology innovation engenders new products of higher qualities and reduces<br />

production costs. We study how a firm leverages future cost reductions to position<br />

its product line toward the high-end in both buyer-side only and two-sided<br />

markets. We find that future cost reductions raise the optimal price of the current<br />

device and trigger an intertemporal buyer-side demand shift forward.<br />

3 - Increasing Revenues from Parking Tickets<br />

Nichalin Summerfield, Adjunct lecturer, University of Arizona,<br />

1130 E. Helen Street, Mclnd 430, Tucson, United States of<br />

America, nichalin@email.arizona.edu, Morris Cohen, Moshe Dror<br />

Parking inspection is modeled as a revenue collecting Chinese Postman Problem.<br />

This approach maximizes expected revenues. We investigate online rules that<br />

allow the enforcement officers to adjust their routes in response to the observed<br />

parking permits’ times. Allowing an officer to selectively wait by legally parked<br />

cars till their permit expires could increase the expected revenues by 7%.<br />

4 - Price and Lead Time Quotation for Contract and Spot<br />

Customers<br />

Baykal Hafizoglu, Arizona State University, 699 S. Mill Avenue,<br />

Tempe, AZ, 85281, United States of America, baykal@asu.edu,<br />

Pinar Keskinocak, Esma Gel<br />

We consider dynamic price and lead time quotation for a make-to-order company<br />

with demand from contract customers as well as spot purchasers. Contract<br />

customers are offered a uniform price and lead time, whereas, spot purchasers are<br />

subject to dynamically quoted price and lead times. We discuss the potential of<br />

dynamic quotation for such environments, various properties of optimal control<br />

policies and the optimal mix of contract customers and spot purchasers.<br />

■ SD27<br />

27- North 221 B- CC<br />

Consumer Behavior Issues in Operations<br />

Sponsor: Manufacturing & Service Oper Mgmt<br />

Sponsored Session<br />

Chair: Omar Besbes, Columbia Business School, 3022 Broadway, New<br />

York, NY, 10027, United States of America, ob2105@columbia.edu<br />

Co-Chair: Ilan Lobel, New York University, Stern Business, 44 W 4th St,<br />

New York, NY, United States of America, ilobel@stern.nyu.edu<br />

1 - The Perils of Rationing under Consumer Regret and<br />

Misperception of Availability<br />

Yanchong Karen Zheng, Massachusetts Institute of Technology,<br />

Sloan School of Management, 100 Main Street, Cambridge, MA,<br />

United States of America, yanchong@mit.edu, Ozalp Ozer<br />

We study the impact of consumers’ regret and misperceived product availability<br />

on a firm’s inventory decision under a markdown policy. We show that both<br />

factors greatly reduce the need for rationing. They act as complements on the<br />

seller’s profit when consumers are modestly risk-averse and markdown is<br />

substantial. In contrast, they act as substitutes for highly risk-averse consumers.<br />

Ignoring these factors can subject the seller to the peril of over-rationing and lead<br />

to excessive profit losses.<br />

INFORMS Phoenix – 2012<br />

139<br />

2 - Strategic Stock-Outs with Social Learning<br />

Yiangos Papanastasiou, PhD Candidate, London Business School,<br />

Regent’s Park, London, NW14SA, United Kingdom, Nicos Savva,<br />

Nitin Bakshi<br />

We study a monopoly firm selling its product to customers holding uncertain,<br />

heterogeneous valuations. Limited availability induces customer self-selection,<br />

with high-valuation customers exerting effort to obtain the product first. We<br />

account for social learning and demonstrate that by inducing an early supply<br />

shortage, a firm can optimally control the information signal emitted from early<br />

reviews. Thereby, the firm can closely mimic dynamic pricing outcomes while<br />

charging a fixed price.<br />

3 - Dynamic Pricing Without Priors<br />

Ying Liu, New York University, 44 West 4th Street, New York, NY,<br />

United States of America, yliu2@stern.nyu.edu, Rene Caldentey,<br />

Ilan Lobel<br />

We consider a setting where a firm is selling a limited inventory of items over<br />

time to strategic customers, but it does not have a prior on the customers’<br />

distributions of values. We construct policies that minimize the maximum regret<br />

the firm could face and present structural properties of such pricing policies.<br />

4 - Cheap Talk in Queues with Multiple Customer Classes<br />

Gad Allon, Northwestern University, 2001 Sheridan Rd, Evanston,<br />

IL, United States of America, g-allon@kellogg.northwestern.edu,<br />

Achal Bassamboo<br />

We examine the problem of information communication by considering a model<br />

in which both the firm and the customers act strategically. In this model, the<br />

customers are heterogeneous both with regards to their waiting cost and the<br />

value they obtain from the service. The customer type is private information. We<br />

characterize the equilibrium language that emerges between the service provider<br />

and her customers.<br />

■ SD28<br />

SD28<br />

28- North 221 C- CC<br />

Models of Customer Behavior<br />

Sponsor: Manufacturing & Service Oper Mgmt<br />

Sponsored Session<br />

Chair: Xuanming Su, University of Pennsylvania,<br />

The Wharton School, Philadelphia, PA, United States of America,<br />

xuanming@wharton.upenn.edu<br />

1 - Consumer Bounded-Rationality: Evidence from the Click<br />

Stream Data<br />

Jun Li, University of Pennsylvania, The Wharton School,<br />

Philadelphia PA 19104, United States of America,<br />

lijun1@wharton.upenn.edu, Serguei Netessine<br />

Using click stream data of online search for air travels, we study how price<br />

volatility affects strategic purchase delays and search frequencies.<br />

2 - Capacity Investment under Bankruptcy Risk with Forward-<br />

Looking Consumers<br />

Robert Swinney, Associate Professor, Graduate School of Business,<br />

Stanford University, 655 Knight Way, Stanford, CA, 94305,<br />

United States of America, swinney@stanford.edu, Song Alex Yang,<br />

Erica Plambeck<br />

We consider the capacity investment decision of a firm that is in financial distress<br />

and may enter bankruptcy. Consumers value firm survival and experience a loss<br />

in utility if bankruptcy occurs. Thus, forward-looking consumers anticipate the<br />

risk of bankruptcy and may delay a purchase to see whether the firm survives.<br />

We analyze optimal capacity decisions in this setting and determine the impact of<br />

such strategic customer behavior on the firm’s profit, survival probability, and<br />

capacity level.<br />

3 - Social Comparisons in Service Cohorts<br />

Guillaume Roels, Assistant Professor, UCLA, 110 Westwood Plaza,<br />

Los Angeles, 90095, United States of America,<br />

guillaume.roels@anderson.ucla.edu, Xuanming Su<br />

We study the effect of social comparisons on individual performance in service<br />

cohorts such as arise in education, health care, and sports industry. We consider<br />

two kinds of social comparison depending on whether customers experience a<br />

disutility from under-performing or a utility gain from over-performing relative to<br />

their peers. We discuss how a service provider should manage her service to<br />

enhance or mitigate the effect of social comparison.


SD29<br />

4 - Pricing Restaurant Reservations<br />

Jaelynn Oh, University of Pennsylvania,<br />

The Wharton School, Philadelphia, PA, United States of America,<br />

jaelynn@wharton.upenn.edu, Xuanming Su<br />

Many restaurants offer reservations to delay sensitive customers and charge a fee<br />

for no-shows. Strategic customers make a reservation only when the expected<br />

utility of doing so is greater than that of walking in without a reservation. We<br />

study the restaurant’s pricing problem when serving both reservation holders and<br />

walk-in customers. We characterize equilibrium prices and profits and discuss<br />

model implications.<br />

■ SD29<br />

29- North 222 A- CC<br />

Staffing and Scheduling in Healthcare Operations<br />

Cluster: Workforce Management<br />

Invited Session<br />

Chair: Arvind Sainathan, Assistant Professor, Nanyang Business School,<br />

Nanyang Technological University, S3-B2A-03, 50 Nanyang Avenue,<br />

Singapore, Singapore, asainathan@ntu.edu.sg<br />

1 - Capacity Allocation between Appointments and Walk-ins with<br />

Endogenous Patient Choice<br />

Sarang Deo, Assistant Professor, Indian School of Business,<br />

Gachibowli, Hyderabad, 500032, India, Sarang_Deo@isb.edu,<br />

Aditya Jain<br />

We consider a healthcare system, wherein each patient decides the mode of<br />

arrival (appointment vs. walk-in) depending on the resulting waiting times<br />

(indirect vs. direct) as well as the severity of patient’s condition. The healthcare<br />

provider decides the allocation of capacity between walk-in and appointment<br />

slots. We analyze the equilibrium of this game and derive managerial insights<br />

about the impact of patient characteristics on capacity allocation decisions.<br />

2 - Multi-objective Robust Adaptive Scheduling for Hospital<br />

Staffing<br />

Kibaek Kim, Northwestern University, 2145 Sheridan Rd., C210,<br />

Evanston, IL, 60208, United States of America,<br />

Kibaek.kim@u.northwestern.edu, Jonathan Turner,<br />

Sanjay Mehrotra<br />

For given mid-term (or long-term) schedules, it is necessary to make short-term<br />

adjustments, either by rescheduling staffs when shortages are anticipated or by<br />

canceling staffs when patient volume drops are anticipated. We develop a multiobjective<br />

robust adaptive scheduling model for the hospital staffing problem.<br />

3 - Hospital Inpatient Design: Analysis and Insights<br />

Mabel Chou, NUS Business School, Level 8, Biz1, Singapore,<br />

Singapore, mabelchou@nus.edu.sg<br />

We study the patient flow management in an inpatient department of a<br />

Singaporean hospital and discuss how to design the system to make the planning<br />

more cost effective. Our analysis generates a number of managerial insights for<br />

inpatient management.<br />

4 - Scheduling Patients by Improving Open Access (same day<br />

appointment) Policy in a Family Medicine Clinic<br />

Abraham Seidmann, Professor, Simon School of Business,<br />

University of Rochester, CS 3-333C, Rochester, NY, 14627,<br />

United States of America, avi.seidmann@simon.rochester.edu,<br />

Balaraman Rajan<br />

We present new empirical and analytical results of our research that focuses on<br />

improving the Open Access (same day appointment) models for scheduling<br />

patients in a family practice setup. We show the value of dynamically<br />

incorporating the effect of anticipated behavior of patients on the expected load of<br />

the clinic.<br />

5 - Nurse Absenteeism and Staffing Strategies for Hospital<br />

Inpatient Units<br />

Wen-Ya Wang, University of Minnesota, 111 Church Street S.E.,<br />

Minneapolis, MN, United States of America, wenya@ie.umn.edu,<br />

Diwakar Gupta<br />

We develop models for determining the number of nurses to assign to inpatient<br />

units when nurse absentee rates are heterogeneous. The assumption of<br />

heterogeneous absentee rates is supported by a detailed analysis of data from<br />

multiple nursing units of two hospitals. We establish structural properties of an<br />

optimal nurse assignment strategy and propose heuristics that perform well in<br />

numerical experiments.<br />

INFORMS Phoenix – 2012<br />

140<br />

■ SD30<br />

30- North 222 B- CC<br />

Energy and Commodity Real Options<br />

Sponsor: Manufacturing & Service Oper Mgmt/iFORM<br />

Sponsored Session<br />

Chair: Nicola Secomandi, Tepper School of Business, Carnegie Mellon<br />

University, Pittsburgh, PA, 15213, United States of America,<br />

ns7@andrew.cmu.edu<br />

Co-Chair: Selvaprabu Nadarajah, Tepper School of Business, Carnegie<br />

Mellon University, 5000Forbes Avenue, Pittsburgh, PA, 15213, United<br />

States of America, snadarajah@cmu.edu<br />

1 - Storage Operations and Investments in an Electrical System<br />

Santhosh Suresh, PhD, Ross School of Business, University of<br />

Michigan, 701 Tappan St., Ann Arbor, MI, 48109, United States of<br />

America, sssandy@umich.edu, Roman Kapuscinski, Owen Wu<br />

Storage technology is becoming increasingly prevalent in today’s electric grid. We<br />

discuss the optimal siting and sizing of storage units in the view of minimizing<br />

overall operating costs accounting for transmission losses unlike individual profit<br />

maximization setting in most previous literature. We show the degree of storage<br />

pooling to be related structurally with: the efficiency of storage and transmission,<br />

variance, correlation and mean in the demand distribution; using a three node<br />

model.<br />

2 - Valuing Renewable Energy Resources<br />

Michael Pavlin, Assistant Professor, Wilfrid Laurier University,<br />

75 University Avenue West, Waterloo, ON, Canada,<br />

Michael.Pavlin06@Rotman.Utoronto.Ca, John Birge<br />

Wind, solar, and other renewable energy resources such as tides and rain have<br />

intermittent availability that makes effective operation and valuation challenging.<br />

We consider the valuation of wind generation for electricity given the structure of<br />

this market and the risk associated with commitment to production.<br />

3 - Managing Wind-based Electricity Generation with Storage and<br />

Transmission Capacity<br />

Yangfang Zhou, PhD Candidate, Carnegie Mellon University,<br />

5000 Forbes Ave., Pittsburgh, PA, 15213 United States of America,<br />

yangfang@andrew.cmu.edu, Alan Scheller-Wolf,<br />

Nicola Secomandi, Stephen Smith<br />

We consider the problem of operating wind-based electricity generation with<br />

storage (for instance, a grid-level electricity battery) in a market. We demonstrate<br />

that mismanaging such a system can significantly reduce its value. We also show<br />

that storage can greatly increase the monetary value of the wind farm, and, while<br />

it typically increases the total energy sold to the market, in certain situations it<br />

may also-– paradoxically—decrease the total wind energy sold to the market.<br />

4 - Valuing Multiple Exercise Options using Term Structure Models<br />

and Approximate Dynamic Programming<br />

Selvaprabu Nadarajah, Tepper School of Business, Carnegie Mellon<br />

University, 5000 Forbes Avenue, Pittsburgh, PA, 15213,<br />

United States of America, snadarajah@cmu.edu, Francois Margot,<br />

Nicola Secomandi<br />

We develop computationally efficient least squares Monte Carlo (LSM) and<br />

approximate linear programming (ALP) methods for valuing multiple exercise,<br />

such as energy swing and storage, options, using term structure price models. Our<br />

theoretical and numerical investigation shows the superiority of an LSM version<br />

based on value, rather than continuation value, function approximation. We also<br />

structurally relate our LSM and ALP methods. This suggests further research on<br />

optimal ALP relaxations.<br />

■ SD31<br />

31- North 222 C- CC<br />

Control the Inventory Risk of Stockout<br />

Cluster: Managing Disruptions in Supply Chains<br />

Invited Session<br />

Chair: Jim Shi, Georgia State University, College of Business, Atlanta,<br />

GA, United States of America, shigsu@gmail.com<br />

1 - Stock-out Risk Control of the Production-Inventory System with<br />

Compound Poisson Demands<br />

Jim Shi, Georgia State University, College of Business, Atlanta, GA,<br />

United States of America, shigsu@gmail.com<br />

We study a single-product continuous-time production-inventory system with a<br />

constant replenishment rate, compound Poisson demands and lost-sales. The<br />

objective is first to derive the expected discounted inventory cost until the<br />

stockout occurrence for any given initial inventory level so as to investigate the<br />

stockout risk.


2 - The Effects of Risk Aversion and Service Constraints on a Twoperiod<br />

Newsvendor Policy<br />

Tatyana Chernonog, Bar Ilan University, Ramat Gan, 52900, Israel,<br />

Tatyana.Chernonog@biu.ac.il, Matan Shnaiderman<br />

This paper presents a two-period newsvendor problem with postponed pricing<br />

strategy. Risk aversion and service constraints are taken into account. These<br />

constraints may affect the optimal inventory capacity as well as the optimal<br />

prices. The effects of the constraints on supply chain performance are compared.<br />

The current two-period model leads to complicated and non-trivial solutions and<br />

insights, compared with one-period models, found in the literature. Exact<br />

analytical formulas are given.<br />

3 - A Risk-averse Dynamic Inventory Model with Fluctuating<br />

Purchasing Costs<br />

Sungyong Choi, Assistant Professor, Yonsei University,<br />

1 Yonseidae-gil, Wonju, 220-710, Korea, Republic of,<br />

sungyongchoi@gmail.com<br />

In my work, dynamic consumption models are studied for finite and infinite time<br />

Markov Decision Process (MDP) problems with fluctuating purchasing costs. I use<br />

additive general and exponential utility functions with finite and infinite time<br />

horizons. In addition, we assume that purchasing costs follow a discrete-state<br />

Markov chain. Then, I consider parametric sensitivity analysis for the model<br />

parameters using super-modularity.<br />

■ SD32<br />

32- North 223- CC<br />

Topics in Manufacturing I<br />

Contributed Session<br />

Chair: Sharafali Moosa, Associate Professor of OM (Edn.), LKC School<br />

of Business, Singapore Managment University, 50 Stamford Road,<br />

Singapore, 178899, Singapore, sharafalim@smu.edu.sg<br />

1 - Wire Path Planning for Multi-axis Wire EDM<br />

Zhi Yang, Kimberly Clark, 1400 Holcomb Bridge Road, Roswell,<br />

GA, 30076, United States of America, zack.yang@kcc.com,<br />

Richard A. Wysk, Sanjay Joshi<br />

Wire path generation methods are introduced. Cutting wire trajectories are<br />

generated under each specified coordinate system based on tangent visibility<br />

results. In order to accomplish the lead-in/lead-out wire path generation<br />

automation, an algorithm is developed to find paths for different types of tangent<br />

visibility results. A cut off plane is introduced to generate the cut off wire path as<br />

the final step of machine operation.<br />

2 - 3D Layout Optimization with Flexible Objects<br />

Sima Maleki, PhD Candidate, University of Tennessee, 416 East<br />

Stadium Hall, Knoxvile, TN, 37996, United States of America,<br />

smaleki@utk.edu, Rapinder Sawhney<br />

This work addresses the multi-layer 3-dimensional packaging of flexible objects<br />

and containers with the aim of maximizing the space utilization. The flexible<br />

containers are filled with rigid and non-rigid objects. Then, the containers are<br />

packed in a bin with fixed size. The problem of filling up containers with<br />

heterogeneous objects and locating the containers in a bin is formulated as a<br />

Mixed Integer Linear Programming model. Results illustrate the effectiveness of<br />

the layout.<br />

3 - Modelling Geometric Variation of Compliant Sheet Metal<br />

Assembly using Statistical Modal Analysis<br />

Abhishek Das, University of Warwick, International Digital<br />

Laboratory, WMG, Coventry, CV4 7AL, United Kingdom,<br />

Abhishek.Das@warwick.ac.uk, Darek Ceglarek<br />

Efficient modelling and analysis of geometric variation is crucial for quality<br />

control of deformable assemblies in automotive and aerospace industries,<br />

especially for emerging technologies such as remote laser welding. Statistical<br />

Modal Analysis using discrete-cosine-transformation is presented through a case<br />

study. The approach models modes of deformation for developing surface-based<br />

SPC.<br />

4 - A Failure-prone System with Delivery Deadline and<br />

Outsourced Maintenance<br />

Sharafali Moosa, Associate Professor of OM (Edn.), LKC School of<br />

Business, Singapore Managment University, 50 Stamford Road,<br />

Singapore, 178899, Singapore, sharafalim@smu.edu.sg,<br />

Hakan Tarakci, Shailesh Kulkarni<br />

We consider a production-maintenance system which is subject to random<br />

breakdowns. The manufacturer has to offer a firm delivery deadline to her<br />

customer. She also has to decide on the maintenance decisions with a<br />

maintenance contractor. A regenerative stochastic process is identified and<br />

analysed to develop the cost function over the finite horizon. Numerical examples<br />

will illustrate the optimization problem. Some managerial insights with regard to<br />

coordination will also be provided.<br />

INFORMS Phoenix – 2012<br />

141<br />

■ SD33<br />

SD33<br />

33- North 224 A- CC<br />

Joint Sessions MSOM/ENRE: Modeling &<br />

Optimization for Electric Vehicles<br />

Sponsor: Manufacturing & Service Oper Mgmt/Sustainable<br />

Operations & Energy, Natural Res & the Envi/ Environment<br />

and Sustainability<br />

Sponsored Session<br />

Chair: Mustafa Dogru, Alcatel-Lucent Bell Labs, 600 Mountain Avenue,<br />

Murray Hill, NJ, 07974, United States of America,<br />

mustafa.dogru@alcatel-lucent.com<br />

1 - Optimal Location of Public Electric Vehicle<br />

Charging Infrastructure<br />

Ramteen Sioshansi, Assistant Professor, The Ohio State University,<br />

240 Baker Systems, 1971 Neil Avenue, Columbus, OH, 43215,<br />

United States of America, sioshansi.1@osu.edu, Xiaomin Xi,<br />

Vincenzo Marano<br />

We develop a simulation optimization based approach to optimize the location of<br />

public electric vehicle charging infrastructure. The model includes budget<br />

constraints and accounts for driving and charging behavior. We use a case study<br />

based on the central Ohio region to demonstrate the model.<br />

2 - Modeling and Optimization for Electric Vehicle<br />

Charging Infrastructure<br />

Mustafa Dogru, Alcatel-Lucent Bell Labs, 600 Mountain Avenue,<br />

Murray Hill, NJ, 07974, United States of America,<br />

mustafa.dogru@alcatel-lucent.com, Matthew Andrews, Yue Jin,<br />

John Hobby, Gabriel Tucci<br />

We have developed a modeling framework to quantify the load on the power grid<br />

due to electric vehicles (EVs) in a metropolitan area during the course of a day.<br />

Our analysis uses driving patterns as an input and utilizes the data from publicly<br />

available surveys conducted in the US. We use this information to optimize the<br />

placement of public charging stations. The analysis also allows us to determine<br />

the percentage of households that are candidates for adopting EVs given the<br />

current technology.<br />

3 - An Integer Programming Model for Generating Vehicle Fleet<br />

Purchase Recommendations<br />

Daniel Reich, Operations Research Analyst, Ford Motor Company,<br />

2101 Village Road, MD 2122, Dearborn, MI, 48124, United States<br />

of America, dreich8@ford.com, Sandy Winkler, Erica Klampfl<br />

Sustainability and environmental impact are areas of growing importance to<br />

many of Ford’s fleet customers. New green vehicle technologies have emerged,<br />

which present organizations with an opportunity to increase the fuel economy of<br />

their fleets. “Fleet Purchase Planner (FPP)” (patent pending) is a software system<br />

designed to assist Ford’s fleet customers in planning their purchases. This talk<br />

introduces FPP and the integer programming model we use to provide customized<br />

purchase recommendations.<br />

4 - Controlled Plug-in Vehicle Charging in High Wind<br />

Penetration Scenarios<br />

Jeremy Michalek, Associate Professor, Carnegie Mellon University,<br />

Scaife Hall 324, 5000 Forbes Ave., Pittsburgh, PA, 15213,<br />

United States of America, jmichalek@cmu.edu, Allison Weis,<br />

Paulina Jaramillo<br />

We construct a MILP model of optimal power plant capacity expansion, dispatch,<br />

and plug-in vehicle charging to estimate the benefits of electric vehicle demand<br />

management using variable rate charging (less costly than bidirectional V2G). We<br />

estimate the implications for system cost, integration of intermittent wind power,<br />

wind curtailment avoided, and peaking plant construction avoided.


SD34<br />

■ SD34<br />

34- North 224 B - CC<br />

The Architecture of Coordination<br />

Cluster: New Product Development<br />

Invited Session<br />

Chair: Alan MacCormack, Harvard Business School, Soldiers Field,<br />

Boston, MA, 02163, United States of America, amaccormack@hbs.edu<br />

1 - Innovation Analytics: using Complexity Science and Big Data<br />

for Sequencing of Products<br />

Nitin Joglekar, Boston University, One Silber Way, Boston, MA,<br />

United States of America, joglekar@bu.edu, Edward Anderson<br />

Many projects are sequentially dependent on one another because their features<br />

and pricing influence market tastes, and vice-versa, thus creating a complex<br />

system. Firms have begun to use “Big Data” from social media and allied sources<br />

to inform underlying decisions. We explore an information scaling framework for<br />

navigating through this complexity.<br />

2 - Managing Distributed Product Development Projects:<br />

Integration Strategies for Language and Geography<br />

Edward Anderson, University of Texas McCombs School of<br />

Business, 1 University Station B6500, Austin, TX, 78712, United<br />

States of America, Edward.Anderson@mccombs.utexas.edu,<br />

Xiaoyue Jiang, Aravind Chandrasekaran<br />

We study two barriers to distributed product development work, (1) geographic<br />

distance and (2) language. Our empirical setting involves 55 projects in 20 focal<br />

firms that outsource complex innovation work to their suppliers. We investigate<br />

the effects of two integration mechanisms used to overcome these barriers, (1)<br />

colocating firm and supplier personnel and (2) giving a “supply chain integrator”<br />

personnel that manage the DPD projects control over key aspects of their projects.<br />

3 - Transparent Environments for Leaky Modules<br />

Jim Herbsleb, Professor, Carnegie Mellon University, 5000 Forbes<br />

Avenue, 5307 Wean Hall, Pittsburgh, PA, 15213, United States of<br />

America, jdh@cs.cmu.edu, Laura Dabbish, Colleen Stuart,<br />

Jason Tsay<br />

Design rules enable concurrent work when organizational structure mirrors the<br />

technical architecture. Perfect modularity, however, is difficult to achieve.<br />

Imperfect modularity requires ongoing coordination of inter-module<br />

dependencies. In this qualitative study, we examine how an emerging generation<br />

of workspaces, explicitly designed around transparency, expose details of ongoing<br />

work and support surprisingly rich inferences about people, activities, technical<br />

direction, and dependencies.<br />

4 - The Human Cost of Complexity: How System Architecture<br />

Affects Developer Productivity<br />

Alan MacCormack, Harvard Business School,<br />

Soldiers Field, Boston, MA, 02163, United States of America,<br />

amaccormack@hbs.edu, Dan Sturtevant<br />

Prior work shows that systems with greater complexity suffer greater quality<br />

problems, in terms of experiencing defects. Few studies however, examine the<br />

human costs of complexity - that is, the impact on the productivity of system<br />

developers. We explore this relationship in a commercial software system. We<br />

find that i) developer productivity is impacted by where in the system<br />

architecture they work, and ii) only skilled developers are allowed to work on the<br />

most complex parts of the system.<br />

■ SD35<br />

35- North 225 A- CC<br />

Bid Price Control in Practice<br />

Sponsor: Revenue Management & Pricing<br />

Sponsored Session<br />

Chair: Darius Walczak, PROS, 3100 Main Street, Suite 900, Houston,<br />

TX, 77002, United States of America, dwalczak@prospricing.com<br />

1 - Bid and List Price Trends in RM and Forward-Looking<br />

Consumers<br />

Ming Hu, Rotman School of Management, University of Toronto,<br />

Toronto, Canada, Ming.Hu@rotman.utoronto.ca, Oded Berman,<br />

Zhan Pang<br />

We characterize a probabilistic property of the bid price process driven by an<br />

optimal policy in a general RM framework: the bid price process always follows<br />

an upward trend. We explore a couple of applications of this structural property.<br />

For example, we show that the optimal list price process also follows an upward<br />

trend if the customers’ WTP does not decrease over time. We draw implications<br />

on forward-looking behavior of strategic consumers.<br />

INFORMS Phoenix – 2012<br />

142<br />

2 - Randomization Approaches for Network RM with Choice<br />

Behavior<br />

Sumit Kunnumkal, Assistant Professor, Indian School of Business,<br />

Gachibowli, Hyderabad, A.P, AP, India, sumit_kunnumkal@isb.edu<br />

We present new approximation methods for the network RM problem with<br />

customer choice behavior. The starting point for our methods is a dynamic<br />

program that allows randomization. An attractive feature of this dynamic<br />

program is that the size of its action space is linear in the number of itineraries.<br />

We present two approximation methods that build on this dynamic program and<br />

use ideas from the independent demands setting.<br />

3 - Estimating Mixtures of Willingness-To-Pay Distributions from<br />

Hotel Rate and Occupancy Data<br />

Chris Keller, Assistant Professor, East Carolina University, College<br />

of Business, 3136 Bate Building, Greenville, NC, 27858,<br />

United States of America, kellerc@ecu.edu<br />

This presentation uses daily rate and occupancy data for a mid-market hotel and<br />

it competitive set to estimate mixtures of distributions for customer willingnessto-pay.<br />

The presentation considers various numbers of mixture distributions and<br />

various types of distributions in order to maximize goodness-of-fit to observed<br />

rates and occupancies. The distributions are also collectively varied by day, week,<br />

and month.<br />

4 - Practical Aspects of Network Bid Price Control<br />

Darius Walczak, PROS, 3100 Main Street, Suite 900, Houston, TX,<br />

77002, United States of America, dwalczak@prospricing.com<br />

Many network carriers rely on bid price control in their day-to-day revenue<br />

management. At the same time they are also often task with providing estimates<br />

of expected revenue, load factor or other measures. We discuss challenges that<br />

arise in deriving those business metrics under bid price control in the network<br />

setting.<br />

■ SD36<br />

36- North 225 B- CC<br />

Pricing and Energy Cost of Cloud<br />

Computing Services<br />

Sponsor: Revenue Management & Pricing<br />

Sponsored Session<br />

Chair: Parijat Dube, IBM, TJ Watson Research Center, Hawthorne, NY,<br />

United States of America, pdube@us.ibm.com<br />

Co-Chair: Genady Ya. Grabarnik, St. John’s University, Queens, NY,<br />

United States of America, grabarng@stjohns.edu<br />

1 - Cost Comparison between Infrastructure Cloud Services<br />

Huan Liu, Accenture Technology Labs, 50 W San Fernando St.,<br />

San Jose, CA, 95113, United States of America,<br />

huan.liu@accenture.com<br />

Infrastructure cloud service providers, such as Amazon EC2, differ widely from<br />

each other in terms of their price structure, which makes it very difficult to<br />

perform an apple-to-apple comparison. In this paper, we describe a methodology<br />

to dissect the price structure into its individual components, including CPU,<br />

memory, and hard disk capacity. We then use the price components to compare<br />

offerings from a few dominate cloud providers.<br />

2 - Selective Commitment and Selective Margin: Techniques to<br />

Minimize Cost in an IaaS Cloud<br />

Yu-Ju Hong, Purdue University, 2550 Yeager Rd Apt 12-1,<br />

West Lafayette, IN, 47906, United States of America,<br />

yujuhong@purdue.edu, Mithuna Thottethodi, Jiachen Xue<br />

We aim to minimize compute cost for day-to-day operations in an Infrastructureas-a-Service<br />

(IaaS) cloud, while satisfying statistical response-time targets. First, a<br />

dynamic programming algorithm is used to compute load-dependent margins (a<br />

set of servers to handle unexpected load bursts). Second, we exploit the<br />

differences of price/commitment of on-demand and reserved virtual machine<br />

instances. Simulations with real Web server traces using Amazon EC2 cost model<br />

show 21% of average cost saving.<br />

3 - Online Dynamic Capacity Provisioning in Data Centers<br />

Minghong Lin, Caltech, 1200 E. California Blvd., Pasadena,<br />

United States of America, mhlin@caltech.edu, Adam Wierman,<br />

Eno Thereska, Lachlan Andrew, Zhenhua Liu<br />

Power consumption imposes a significant cost for data centers, yet much of that<br />

power is used to maintain excess service capacity during periods of low load. In<br />

this work, we study how to avoid such waste via an online dynamic capacity<br />

provisioning. We show that the optimal offline algorithm has a simple structure<br />

when viewed in reverse time, and develop a lazy online algorithm which is 3competitive.<br />

Additionally, we analyze the traditional receding horizon control and<br />

introduce a new variant.


4 - Distributed Resource Allocation in Large Scale Data<br />

Intensive Computing<br />

Cathy Xia, Professor, Ohio State University, 210 Baker,<br />

1971 Neil Ave., Columbus, OH, 43210, United States of America,<br />

xia.52@osu.edu, Kevin Liu, Ness Shroff<br />

In cloud computing, distributed management of resources for effective dataintensive<br />

in-network computing is critical. We consider the optimal resource<br />

allocation problem in this context using a network utility optimization<br />

framework. We provide second-order based distributed control algorithms with<br />

guaranteed quadratic convergence speed.<br />

5 - Energy Cost and Availability Considerations in Cloud<br />

Services Composition<br />

Parijat Dube, IBM, TJ Watson Research Center, Hawthorne, NY,<br />

United States of America, pdube@us.ibm.com<br />

Compute service provider has the flexibility to use its own private nodes or use<br />

nodes from public domain when composing services. However there are cost and<br />

availability concerns associated with both private nodes and public nodes. The<br />

goal is to construct compute services which satisfy end-to-end delay requirements<br />

of a job while minimizing cost and maintaining reliability. We propose simple<br />

heuristics and their empirical verification.<br />

■ SD37<br />

37- North 226 A- CC<br />

Alternative Fuels, Stations, and Vehicles I<br />

Sponsor: Location Analysis<br />

Sponsored Session<br />

Chair: Michael Kuby, Professor, Arizona State University, Tempe, AZ,<br />

85287-5302, United States of America, mikekuby@asu.edu<br />

1 - Effects of Electric Vehicles Adoption Pathway on the<br />

US Energy System<br />

Dong Gu Choi, Georgia Institute of Technology, 765 Ferst Drive,<br />

NW, Room 336, Atlanta, GA, 30332, United States of America,<br />

doonggus@gatech.edu, Frank Kreikebaum, Deepakraj Divan,<br />

Valerie Thomas<br />

Adoption of electric vehicles (EVs) can affect the development of the electric<br />

power system, the integration of intermittent renewable energy, and the overall<br />

efficiency of the vehicle fleet, with implications for costs, environmental impacts,<br />

and policy implementation. Using a set of models spanning the light-duty vehicle<br />

fleet and the electric power system, we evaluate numerous scenarios for EV<br />

integration into the energy system in eastern U.S. and argue linkages among the<br />

considerations.<br />

2 - Shortest Routes with Refueling Stops<br />

Pitu Mirchandani, Arizona State University, 699 South Mill<br />

Avenue, Tempe, AZ, 85287, United States of America,<br />

pitu@asu.edu, Jonathan Adler, Guoliang Xue<br />

Unlike the problem of shortest paths and shortest path trees, when refueling stops<br />

are not required, and where well known algorithms exist for finding shortest path<br />

trees, the problem of finding shortest routes with refueling may require detouring<br />

for refueling, which may result in walks with cycles. A polynomial algorithm is<br />

presented for finding the set of shortest walks for all node pairs in the network.<br />

3 - The Vehicle Scheduling Problem with Electric Vehicles<br />

Jonathan Adler, Arizona State University, 699 S. Mill Ave.,<br />

Tempe, AZ, 85281, United States of America, jonadler@asu.edu,<br />

Pitu Mirchandani<br />

The Vehicle Scheduling Problem (VSP) consists of assigning a fleet of vehicles to<br />

travel a certain set of trips with given start and end times. VSP changes when the<br />

fleet is composed of electric vehicles, since the vehicles can only travel a limited<br />

distance before needing to recharge or exchange batteries. In this talk we will<br />

define and formulate the problem of using electric vehicles in these scheduling<br />

settings, show the problem is NP-hard, and present a heuristic solution.<br />

4 - Distributed Joint Budget Allocation and Location Problem for<br />

Alternative-fuel Stations<br />

Ismail Capar, Assistant Professor, Texas A&M University, TAMU<br />

3367, College Station, TX, 77843, United States of America,<br />

capar@tamu.edu, In-Jae Jeong<br />

Government agencies (GAs) around the world are providing grants to service<br />

providers (SPs) for building infrastructure for alternative-fuel vehicles (AFVs).<br />

While GAs aim to increase the number of adopters; SPs want to maximize profit.<br />

These objectives may not be well aligned. We consider this joint funding<br />

allocation and AFV station location problem under partial information sharing<br />

where parties do not reveal the private information of individual objective<br />

functions and budget constraints.<br />

INFORMS Phoenix – 2012<br />

143<br />

5 - Hydrogen Charging Station Location Analysis with Scheduling<br />

and Routing Considerations<br />

Jamie Kang, Institute of Transportation Studies, University of<br />

California, Irvine, 4000 AIRB, Irvine, CA, United States of<br />

America, jekang@uci.edu, Will Recker<br />

A facility location problem with full-day scheduling and routing considerations is<br />

proposed for hydrogen refueling stations in the early adoption stage. The model<br />

uses the set covering model as a location strategy, and the Household Activity<br />

Pattern Problem as the scheduling and routing tool. The formulation isolates each<br />

vehicle’s routing problem from other vehicles as well as the set covering problem,<br />

and uses a modified column generation that finds a column with a negative<br />

reduced price.<br />

■ SD38<br />

SD38<br />

38- North 226 B- CC<br />

Public Services Applications<br />

Sponsor: Service Science<br />

Sponsored Session<br />

Chair: Robert Saltzman, Professor, Decision Sciences, San Francisco<br />

State University, 1600 Holloway Avenue, San Francisco, CA, 94132,<br />

United States of America, saltzman@sfsu.edu<br />

1 - Planning for an Aging Fleet of Shuttle Vehicles with Simulation<br />

Robert Saltzman, Professor, Decision Sciences, San Francisco State<br />

University, 1600 Holloway Avenue, San Francisco, CA, 94132,<br />

United States of America, saltzman@sfsu.edu<br />

A university operates an aging fleet of shuttle vehicles that facilitate travel by its<br />

affiliates to, from and around campus. This paper presents an animated discreteevent<br />

simulation model that can be used by campus planners to make capital<br />

planning decisions about the fleet. Experiments were run to identify the best type<br />

of shuttle to replace existing vehicles and to quantify how different fleet<br />

configurations might accommodate various future increases in ridership.<br />

2 - Using Stochastic Processes and Behavioral Analysis to Support<br />

Search and Rescue Operations<br />

Johnathon Dulin, Concurrent Technologies Corporation, 771<br />

Fairdale Ct, Castle Rock, CO, 80104, United States of America,<br />

dulinj@ctc.com<br />

Optimizing search patterns has long been a focus in the OR community, and it is<br />

generally accomplished in two veins: probabilistic analysis to develop a fixed<br />

pattern or automated learning to direct progress. But is it possible that the two<br />

could meet in the middle? In this talk we describe an approach that does just this.<br />

By merging the behavioral elements of game theory with the policy optimization<br />

of MDPs, our combined approach finds smarter search paths by allowing real-time<br />

updates.<br />

3 - Police Control Room Emergency Response Behaviour Analysis<br />

Partha Datta, Associate Professor, IIM Calcutta, Diamond Harbour<br />

Road, Joka, Calcutta, WB, 700104, India, ppdatta@iimcal.ac.in<br />

The primary issue explored in this research is how demand distortions called the<br />

‘bullwhip’ effect, create inefficiencies for responding to emergency calls in police<br />

control rooms. In this paper, we demonstrate the existence of bullwhip effect in<br />

the emergency service sector through case study of Indian police control room.<br />

We explore the impact of call handler’s behavioral differences.<br />

4 - Evaluating an Automatic Data Sharing Tool for<br />

Municipal Governments<br />

Stacy Hobson, IBM T. J. Watson Research Center, 19 Skyline<br />

Drive, Hawthorne, NY, 10532, United States of America,<br />

stacypre@us.ibm.com<br />

Coordination of data from multiple departmental applications are critical for<br />

municipalities to provide services to its citizens, yet the prevalence of silos<br />

between applications requires significant amounts of manual data sharing. We<br />

present our work in creating the Shared Data Manager (SDM) – a tool to for<br />

loosely-coupled and customizable application integration and findings of our<br />

study on the use of the SDM as a means to improve data sharing and<br />

coordination within municipal governments.


SD39<br />

■ SD39<br />

39- North 226 C- CC<br />

Electronic and Mobile Retailing Services<br />

Sponsor: Service Science<br />

Sponsored Session<br />

Chair: Howard Hao-Chun Chuang, PhD Candidate, Mays Business<br />

School at Texas A&M University, College Station, TX, 77843-4217,<br />

United States of America, hchuang@mays.tamu.edu<br />

1 - From E-commerce to M-commerce: Business Value of Mobile<br />

Sales Channel<br />

Yen-Chun Chou, Arizona State University, United States of<br />

America, Yen-Chun.Chou@asu.edu, Benjamin Shao<br />

M-commerce represents an emerging subset of e-commerce and is projected to<br />

reach 31 billion by 2016. While firms embrace mobile sales channels, one critical<br />

question is how they can reap values from the new channels. We aim to answer<br />

the question by considering prior e-commerce establishments, timing of mobile<br />

channel implementation, and a firm’s general business operations. Our study<br />

contributes to research and practice by exploring factors that influence mcommerce<br />

performances.<br />

2 - Visualization of Contents-oriented Services<br />

Chie-Hyeon Lim, Pohang University of Science and Technology,<br />

Engineering Building #4-316, Pohang, Korea, Republic of,<br />

arachon@postech.ac.kr, Kwang-Jae Kim<br />

A contents-oriented service is a type of service in which service contents have<br />

major roles in service provision. Examples include car-infotainment services and<br />

internet-based education services. This talk presents issues regarding the<br />

visualization of contents-oriented services. The conventional service blueprint and<br />

other existing tools for service visualization are reviewed for the visualization of<br />

contents-oriented services; the limitations and alternatives are also discussed.<br />

3 - Impact of Website Functionalities on e-Retailer Sales: An<br />

Econometric Analysis<br />

Guanyi Lu, PhD Candidate, Mays Business School at Texas A&M<br />

University, 320N, 4217 TAMU, College Station, TX, 77843-4217,<br />

United States of America, glu@mays.tamu.edu, Xiaosong Peng,<br />

Howard Hao-Chun Chuang, Gregory Heim<br />

Utilizing a three-year panel data set of top500 Internet retailers, we examine the<br />

effects of various web functionalities on retailer sales. The results suggest that<br />

only value-added web functionalities exhibit a direct and sizable effect on web<br />

sales; the effects of fundamental and customer-centered web functionalities<br />

appear to be non-substantial.<br />

4 - Operating Efficiency of Internet Retailers<br />

Howard Hao-Chun Chuang, PhD Candidate, Mays Business School<br />

at Texas A&M University, College Station, TX, 77843-4217, United<br />

States of America, hchuang@mays.tamu.edu, Gregory Heim,<br />

Rogelio Oliva<br />

We empirically assess the operating efficiency of Internet retailers using stochastic<br />

non-smooth envelopment of data. In the first stage, we adopt concave<br />

nonparametric least squares (CNLS) to tackle estimation bias incurred by<br />

contextual variables. In the second stage, we decompose CNLS residuals and<br />

derive efficiency estimates. We conclude by discussing the methodological<br />

implications of contextual variables and the managerial implications of e-retail<br />

efficiency.<br />

■ SD40<br />

40- North 227 A- CC<br />

Ecosystem Conservation<br />

Sponsor: Energy, Natural Res & the Envi/ Environment and<br />

Sustainability<br />

Sponsored Session<br />

Chair: Hayri Onal, University of Illinois at Urbana-Champaign,<br />

305 Mumford Hall, Urbana, IL, 61801, United States of America,<br />

h-onal@illinois.edu<br />

1 - Optimal Surveillance and Eradication of Invasive Species<br />

Robert Haight, USDA Forest Service, 1992 Folwell Ave.,<br />

St. Paul, MN, 55108, United States of America, rhaight@fs.fed.us,<br />

John Kean, Rebecca Epanchin-Niell, Andrew Liebhold,<br />

Ludek Berec<br />

Cost-effective surveillance strategies are needed for efficient responses to<br />

biological invasions of terrestrial ecosystems. Surveillance strategies are applied in<br />

environments with continual invasion pressure, unknown number, size, and<br />

location of populations, and trade-offs between surveillance effort and<br />

INFORMS Phoenix – 2012<br />

144<br />

management costs. We develop a decision model that accounts for these features<br />

and determines the long term equilibrium sampling effort that minimizes total<br />

expected costs of new invasions.<br />

2 - A Modeling Framework for Life History-based<br />

Conservation Planning<br />

Sandor Toth, Assistant Professor, University of Washington, School<br />

of Environmental and Forest Scien, Seattle, WA, 98195, United<br />

States of America, toths@uw.edu, Eileen S. Burns, Robert Haight<br />

We present a new population protection function for reserve site selection models<br />

that determines whether minimum habitat requirements are present in a given<br />

reserve network. We embedding the function in an integer programming-based<br />

reserve selection model and apply it to a case study of Myotis bat conservation on<br />

Lopez Island, United States. Finally, we highlight the need in future reserve<br />

design models to capture intra- and inter-species competition for habitat<br />

resources.<br />

3 - Robust Network Design for Multispecies Conservation<br />

Bistra Dilkina, Cornell University, Ithaca, NY, 14853, United States<br />

of America, bistra@cs.cornell.edu, Ronan Le Bras, Yexiang Xue,<br />

Carla Gomes<br />

Ideally conservation plans should ensure the connectivity of habitat areas is<br />

robust to changes in the landscape. We introduce the Shortest Maximally<br />

Connected Network Design problem, which captures the need to both protect<br />

multiple edge-disjoint paths as well as minimize the species-specific resistance<br />

length of such paths, and provide solution approaches. Our models extend to<br />

multispecies conservation, providing a tool to systematically study tradeoffs<br />

between species, in addition to costs.<br />

4 - Designing a Conservation Reserve with Optimum<br />

Functional Connectivity<br />

Hayri Onal, University of Illinois at Urbana-Champaign,<br />

305 Mumford Hall, Urbana, IL, 61801, United States of America,<br />

h-onal@illinois.edu, Yicheng Wang<br />

Spatial contiguity of conservation reserves is crucial for effective functioning of<br />

the reserved areas and improving species survival chances. Just physical<br />

contiguity may not always be adequate, quality of the connecting areas is<br />

important also. We present a linear MIP model for determining an optimal<br />

functionally connected reserve while meeting other conservation criteria and an<br />

empirical application to a real data set.<br />

■ SD41<br />

41- North 227 B- CC<br />

Uncertainty in Energy<br />

Contributed Session<br />

Chair: Bruno Flach, RSM, IBM Research, Brazil, bflach@br.ibm.com<br />

1 - Payment Uncertainty Management in a Combined Market of<br />

Energy and Reserve<br />

Taìsa Felix, Universidade de Brasìlia, SHCGN 703 Bloco L apto 103,<br />

Brasìlia, BR, 70730712, Brazil, taisafelix@gmail.com<br />

As a rule, power system markets operate considering bid cost minimization<br />

(BCM) in clearing processes. This procedure has inconsistency because the total<br />

BCM is different from the load payment. This work introduce a combined market<br />

model of energy and reserve operating under Payment Minimization (PM),<br />

transforming the problem in a bi-level linear model, which can be solved using<br />

GAMSÆ. Expected payment is evaluated using Monte Carlo simulation,<br />

providing results to evaluate the PM energy policy.<br />

2 - Robust Unit Commitment Problem with Demand and<br />

Market Price Uncertainty<br />

Michele Samorani, Alberta School of Business, University of<br />

Alberta, Edmonton, AB, Canada, samorani@ualberta.ca,<br />

Manuel Laguna, Fabio Furini<br />

The unit commitment problem must be solved periodically by the grid operator in<br />

order to find the optimal energy production plan. We extend existing solution<br />

methods by taking into account the uncertainty of the demand and of the energy<br />

prices. We test the performance of robust optimization strategies on real data of<br />

energy demand. Our results suggest that significant savings can be achieved by<br />

adopting the minimax regret criterion.<br />

3 - An MIQP Approach to the Determination of Analogous<br />

Reservoirs<br />

Bruno Flach, RSM, IBM Research, Brazil, bflach@br.ibm.com<br />

Oil companies are constantly faced with decision under uncertainty problems<br />

related to the analysis of potential investments in target reservoirs. Our work<br />

focuses on the determination of analogous reservoirs as a way to estimate<br />

unknown properties and production forecatsts by formulating it as a mixed<br />

integer quadratic programming (MIQP) problem. Computational results on the<br />

application of different solution algorithms to a realistic large-scale problem will<br />

be discussed.


4 - An Optimal Solution to the Discrete Price-based Dynamic<br />

Economic Dispatch Problem<br />

Pawel Kalczynski, Professor of Inf. Syst. and Dec. Sci., California<br />

State University-Fullerton, Mihaylo College of Business and Econ.,<br />

P.O. Box 6848, Fullerton, CA, 92831-6848,<br />

United States of America, PKalczynski@fullerton.edu<br />

A new approach to the price-based dynamic economic dispatch (PBDED) of fossilfuel<br />

electricity generators is presented; temperature is the decision variable. The<br />

objective is to maximize profit over a discrete time horizon when the fuel and<br />

electricity prices (or forecasts) are given. An optimal solution can be found using<br />

the dynamic-programming approach. The model allows for representing different<br />

types of fossil-fuel generators; it can used to compare bidding strategies and price<br />

forecasts.<br />

■ SD42<br />

42- North 227 C- CC<br />

Traffic and ITS<br />

Contributed Session<br />

Chair: Mostafa Badakhshian, PhD Student, Concordia University,<br />

2525 Boul Cavendish, Montreal, QC, H4B 2Y6, Canada,<br />

m.badakhshian@gmail.com<br />

1 - Priority Traffic Signal Control in an Actuated Control System<br />

Larry Head, Department Head, Systems and Industrial<br />

Engineering, University of Arizona, P.O. Box 210020, Tucson, AZ,<br />

85721, United States of America, larry@sie.arizona.edu, Jun Ding,<br />

Qing He, Wei Wu<br />

Traffic signals provide service for multiple modes of travelers including vehicles,<br />

trucks, transit, pedestrians and bicycles, and emergency vehicles. Historically, the<br />

treatment for each mode of traveler was addressed somewhat independently<br />

within the normal traffic signal operation (vehicles). This paper addresses a<br />

decision framework for prioritizing requests for service from multiple modes and<br />

accommodating the authorized requests within an integrated framework.<br />

2 - Monitoring Traffic Shock Waves on the Roads via Massive<br />

GPS Probes<br />

Young-Ji Byon, Assistant Professor, Khalifa University of Science<br />

Technology and Research, Al Saada St. (19th) and 4th Street,<br />

P.O. Box 127788, Abu Dhabi, 127788, United Arab Emirates,<br />

youngji.byon@kustar.ac.ae, Raja Jayaraman, Young Seon Jeong,<br />

Said Easa<br />

Until now, intelligent transportation system (ITS) applications have focused on<br />

speed, density and volume of the general traffic on particular sections of roads.<br />

A more direct method of traffic monitoring can be achieved by capturing<br />

“shockwaves” with GPS probes. Shockwaves generally travel backwards on the<br />

road and can create grid-locks at major intersections. By monitoring the<br />

movements of the shockwaves, real-time route guidance can be improved.<br />

3 - Travel Time Reliability for Extended Freeway Facilities<br />

Ali Hajbabaie, Postdoctoral Research Scholar, Institute for<br />

Transportation Research and Education-North Carolina State<br />

University, 909 Capability Drive, Suite 3600, Research Building IV,<br />

Raleigh, NC, 27606, United States of America, ahajbab@ncsu.edu,<br />

Behzad Aghdashi, Nagui Rouphail<br />

In this study, we introduce a methodology to incorporate reliability measures in<br />

travel time estimation of extended freeway facilities. The methodology is designed<br />

to account for non-recurring sources of congestion such as inclement weather<br />

events and traffic incidents. Travel time reliability method, several reliability<br />

performance measures, and numerical findings of a real-world case study will be<br />

explained.<br />

4 - An Analytical Approximation of the Joint Distribution of Queuelengths<br />

in an Urban Network<br />

Carter Wang, Massachusetts Institute of Technology, 235 Albany<br />

Street, #2021, Cambridge, MA, 02139, United States of America,<br />

carterw@mit.edu, Carolina Osorio<br />

We propose a methodology to approximate the joint distribution of queue lengths<br />

in an urban network. The main issues are dimensionality and modeling<br />

dependency analytically. We approximate network-wide joint distributions by<br />

combining a finite capacity queueing network model with an analytical<br />

aggregation-disaggregation technique. The approach is analytical and<br />

differentiable and can be embedded within optimization frameworks to address<br />

efficiently a variety of urban transportation problems.<br />

INFORMS Phoenix – 2012<br />

145<br />

■ SD43<br />

43- North 228 A- CC<br />

Joint Session RAS/CPMS: Panel Discussion<br />

Continued: Analytics and Intermodal<br />

Sponsor: Railway Applications & CPMS, The Practice Section<br />

Sponsored Session<br />

Chair: Bruce Patty, Vice President, Veritec Solutions, 824 Miramar<br />

Terrace, Belmont, CA, 94002, United States of America,<br />

bpatty@veritecsolutions.com<br />

1 - Roundtable on Analytics and Intermodal<br />

Moderator: Bruce Patty, Vice President, Veritec Solutions, 824<br />

Miramar Terrace, Belmont, CA, 94002, United States of America,<br />

bpatty@veritecsolutions.com, Panelists: Michael Gorman,<br />

Steve Sashihara, Dharma Acharya<br />

This roundtable will take place during two sessions. During this second session,<br />

there will be three panelists from the OR community (Mike Gorman from the<br />

University of Dayton, Steve Sashihara from Princeton Consultants, and Dharma<br />

Acharya from CSX) who will share their thoughts about current and potential<br />

applications of analytics to the intermodal industry. After their opening<br />

presentations, there will be an opportunity for the audience to ask questions and<br />

participate in an open discussion.<br />

■ SD44<br />

44- North 228 B- CC<br />

Information in Supply Chain<br />

Contributed Session<br />

SD44<br />

Chair: Eirini Spiliotopoulou, PhD Candidate in Supply Chain<br />

Management, MIT-Zaragoza International Logistics Program,<br />

Zaragoza Logistics Center, Zaragoza, 50197, Spain,<br />

espiliotopoulou@zlc.edu.es<br />

1 - Optimal Replenishment Policies for Deteriorating Items Based<br />

on the Forecasting Method of Grey Model<br />

Shoufeng Ji, Professor, Northeastern University, No.11, Lane 3,<br />

WenHua Road, HePing District, Liaoning, Shenyang, 110004,<br />

China, sfji@mail.neu.edu.cn, Haifei Yu<br />

The collected and forecasting profit model was briefly introduced focus on a series<br />

of conditions such as limited inventory, stochastic replenishment periods,<br />

uncertain of whether lending stock and service level constraint. Then determinate<br />

the optimal replenishment quantity and optimal policy and utilize MATLB realtime<br />

simulation to analyze how lending stock rate and stochastic replenishment<br />

periods effluence the profit .Finally it is proved that model is validated to the<br />

policy.<br />

2 - Mechanisms to Induce Buyer Forecasting: Do Suppliers Always<br />

Benefit from Better Forecasting?<br />

Thunyarat (Bam) Amornpetchkul, University of Michigan,<br />

701 Tappan St., Ann Arbor, MI, 48109, United States of America,<br />

thunyara@umich.edu, Ozge Sahin, Izak Duenyas<br />

We consider a supplier’s contract offerings to a buyer who may obtain more<br />

precise or more accurate demand forecasts closer to the selling season. We<br />

investigate optimal contract types both when the supplier is certain and uncertain<br />

of the buyer’s forecasting capability. We propose new mechanisms which<br />

effectively induce the buyer to obtain better forecasts and always yield a higher<br />

profit to the supplier, compared to conventional contract types considered in the<br />

literature.<br />

3 - The Value of Real-time Advance Demand Information in Lotsizing<br />

Decision Making<br />

Qiannong Gu, Sam Houston State University, 1419 Eden Meadows<br />

Dr, Spring, TX, 77386, United States of America,<br />

qian_nong@yahoo.com, Basheer Khumawala, John Visich<br />

Advance demand information captured by a real time information tracking<br />

technology offers an opportunity for the manufacturer in a supply chain to make<br />

more efficient lot-sizing decisions. This research studies the trade-off between lot<br />

setup costs and inventory holding costs in a lot-sizing problem by using the realtime<br />

ADI.


SD45<br />

4 - Information Reliability in Supply Chains: The Case of<br />

Multiple Retailers<br />

Eirini Spiliotopoulou, PhD Candidate in Supply Chain<br />

Management, MIT-Zaragoza International Logistics Program,<br />

Zaragoza Logistics Center, Zaragoza, 50197, Spain,<br />

espiliotopoulou@zlc.edu.es, Mustafa Cagri Gurbuz,<br />

Karen Donohue<br />

Multiple retailers consider to form a pooling coalition and delegate inventory<br />

management to a benevolent central planner. Each retailer faces uncertain<br />

demand and has private information about it due to his proximity to the market.<br />

We focus on whether reliable demand information sharing occurs between<br />

retailers and the central planner and on the impact of a) the size of the pooling<br />

coalition and b) the market uncertainty on the level of trust and trustworthiness<br />

of supply chain parties.<br />

5 - Information Sharing in Supply Chain of Durable Goods<br />

Neda Khanjari, PhD Student, Northwestern University, 2145<br />

Sheridan Road, Evanston, IL, 60202, United States of America,<br />

neda@u.northwestern.edu, Seyed Iravani, Hyo duk Shin<br />

We study a supply chain of a durable good product consisted of a retailer with<br />

advance demand information and a manufacturer. The retailer and the<br />

manufacturer play a pricing game. We study how the policy of the retailer to<br />

share his information with the manufacturer depends on durability of the product<br />

and other parameters of the model. We find conditions under which the retailer<br />

shares information with the manufacturer and study the impact of information<br />

sharing on the supply chain profits.<br />

■ SD45<br />

45- North 229 A- CC<br />

Panel Discussion: WORMS: Advice on Promotion to<br />

Full from Associate Professor<br />

Sponsor: Women in OR/MS<br />

Sponsored Session<br />

Chair: Mary E. Kurz, Associate Professor, Clemson University, Industrial<br />

Engineering, 110 Freeman Hall, Clemson, SC, 29634, United States of<br />

America, MKURZ@clemson.edu<br />

1 - WORMS: Advice on Promotion to Full from Associate<br />

Professor Panel<br />

Moderator: Mary E. Kurz, Associate Professor, Clemson University,<br />

Industrial Engineering, 110 Freeman Hall, Clemson, SC, 29634,<br />

United States of America, MKURZ@clemson.edu, Panelists:<br />

Aleda Roth, Susan Sanchez, Beril Toktay, Julie Higle<br />

In this panel, we will discuss the experiences, observations and receive advice<br />

from several successful female faculty housed in different types of departments<br />

and institutions, focusing on the transition from associate to full professor.<br />

■ SD46<br />

46- North 229 B- CC<br />

Joint Session ORG/TMS: Organizing for Innovation in<br />

the Digitized World<br />

Sponsor: Organization Science & Technology Management<br />

Sponsored Session<br />

Chair: Youngjin Yoo, Temple University, 1810 N. 13th Street,<br />

Speakman Hall, Philadelphia, PA, 19122, United States of America,<br />

yxy23yoo@gmail.com<br />

1 - Digital Science and Knowledge Boundaries<br />

Deborah Dougherty, Rotgers University, 94 Rockafeller Rd, Janice<br />

H. Levin Rm 26, Piscataway, NJ, 08854, United States of America,<br />

doughert@business.rutgers.edu<br />

Drug discovery has many unpredictable interdependencies. Science digitalization<br />

affords ways to measure, analyze, and model chemical compounds, diseases, and<br />

biology.We build on epistemic cultures to develop theory for integrating digital<br />

sciences. Digitalization creates essential knowledge and new knowledge<br />

boundaries around central activities of innovation. We explain how innovation<br />

activities can be transformed to integrate digital science into drug discovery.<br />

INFORMS Phoenix – 2012<br />

146<br />

2 - Reconfiguring Boundary Relations: Robotic Innovations in<br />

Pharmacy Work<br />

Eivor Oborn, Professor, School of Management, Royal Holloway<br />

University of London, Egham London, United Kingdom,<br />

eivor.oborn@rhul.ac.uk, Wanda Orlikowski, JoAnne Yates,<br />

Michael Barrett<br />

We explore the influence of robotic innovations on the boundary dynamics of<br />

three different occupational groups and extend conceptually Pickering’s tuning<br />

approach to examine the entanglement of mechanical elements and digital<br />

inscriptions. The robot’s hybrid and digital materiality over time reconfigured<br />

boundary relations among the three occupational groups with important and<br />

contradictory consequences for the pharmacy workers’ skills, jurisdictions, status<br />

and visibility.<br />

3 - Catalyzing Collaboration Amongst Strangers: Field<br />

Experimental Evidence<br />

Karim Lakhani, Assistant Professor, Harvard Business School,<br />

Boston, MA, United States of America, k@hbs.edu, Patrick Gaule,<br />

Christoph Riedl, Kevin Boudreau, Anita Woolley<br />

We used a field experiment to investigate the emergence of collaboration in 52<br />

groups (5 members) of software developers. We test theoretical predictions from<br />

different disciplines – regarding the factors leading to the emergence of<br />

collaboration. We find that monetary rewards powerfully shape the effort that<br />

workers exert in their work. However, we also find substantial evidence for the<br />

existence of peer effects, whereby individuals exert more effort when other team<br />

members work harder.<br />

4 - Digital Innovation and the Division of Innovative Labor: Digital<br />

Controls in the Automotive Industry<br />

Jaegul Lee, Wayne State University, Detroit, MI, 48202,<br />

United States of America, jaegul.lee@wayne.edu<br />

Much of organizational scholarship holds that, accompanying a shift toward<br />

modular structures, suppliers tend to engage in invention around the components<br />

they supply. In this study, we find that in the wake of a major shift in the digital<br />

controls technology, suppliers engage in relatively less component innovation in<br />

comparison with their OEMs. By analyzing the evolution of automotive emission<br />

control systems, we explain this shift by offering two views about the interfirm<br />

division of labor.<br />

■ SD47<br />

47- North 230- CC<br />

Traffic Control Schemes and Applications II<br />

Sponsor: Transportation Science & Logistics/ Intelligent<br />

Transportation Systems (ITS)<br />

Sponsored Session<br />

Chair: Qing He, IBM Watson Research Center, 1101 Kitchawan Rd,<br />

Yorktown Heights, NY, 10598, United States of America,<br />

qhe@us.ibm.com<br />

1 - Energy-efficient Traffic Management: A Microscopic<br />

Simulation-based Approach<br />

Carolina Osorio, Assistant Professor, Massachusetts Institute of<br />

Technology, Room 1-232, 77 Massachusetts Avenue, Cambridge,<br />

MA, 02139, United States of America, osorioc@mit.edu,<br />

Kanchana Nanduri<br />

We use detailed traffic and fuel models to address a fixed-time signal control<br />

problem for the Swiss city of Lausanne. We have developed an optimization<br />

framework with good short-term performance using a metamodel that combines<br />

information from the simulator and an analytical queuing model. The method is<br />

able to identify signal plans with improved travel times and energy consumption<br />

even under tight computational budgets.<br />

2 - Optimal Speed Trajectory for Fuel Consumption Reduction at<br />

Signalized Intersection<br />

Xiaozheng He, University of Minnesota, 500 Pillsbury Dr. SE,<br />

Minneapolis, MN, 55414, United States of America,<br />

hexxx069@umn.edu, Henry Liu<br />

In this study, we formulate optimal speed trajectories at signalized intersection as<br />

solutions to a multi-phase optimal control problem, which considers the impact<br />

from vehicle queues due to traffic lights. By applying the pseudospectral method,<br />

this multi-phase optimal control problem is reformulated into a nonlinear<br />

programming problem which can be solved effectively. We demonstrate the<br />

effectiveness of the proposed model by an example.


3 - A Bi-level Formulation for the Combined Dynamic Equilibrium<br />

Based Traffic Signal Control<br />

Kien Doan, Purdue University, 550 Stadium Mall Drive, West<br />

Lafayette, IN, 47906, United States of America, dtkien@gmail.com,<br />

Satish Ukkusuri<br />

This paper formulates a combined dynamic signal control optimization (SCO)<br />

with dynamic user equilibrium (DUE) using a bi-level formulation. A path-based<br />

CTM is embedded as the traffic flow model to capture the different O-D flows at<br />

all cells and links and there is no holding-back problem in the entire network. A<br />

specialized solution technique will be developed for this problem and rigorously<br />

studied to solve general networks. We use a heuristic algorithm based on the<br />

projection method to solve the lower level (DUE) problem. A mixed integer<br />

programming (MIP) and other extensions are proposed to solve the upper level<br />

signal optimization. Extensive numerical results will illustrate the benefits of<br />

using this model and algorithm.<br />

4 - Traffic Control Agency Planning and Signal Optimization for<br />

Special Planned Events<br />

Qing He, IBM Watson Research Center, 1101 Kitchawan Rd,<br />

Yorktown Heights, NY, 10598, United States of America,<br />

qhe@us.ibm.com, Arun Hampapur, Xuan Liu<br />

Large scale special planned events, attracting both high volume of pedestrians and<br />

vehicles, result in significant nonrecurrent congestion as well as queue spillover.<br />

In this research, we proposed a mixed intersection control model utilizing both<br />

manual control from traffic control agency (TCA) and automatic signal control.<br />

Different with traffic signals, TCA can effectively balance queues and increase<br />

throughput, and prevent intersection capacity drop caused by large volume of<br />

pedestrians.<br />

■ SD48<br />

48- North 231 A- CC<br />

Logistics System Planning<br />

Sponsor: Transportation Science & Logistics/ Freight<br />

Transportation & Logistics<br />

Sponsored Session<br />

Chair: Alan Erera, Professor, Georgia Institute of Technology, 765 Ferst<br />

Dr NW, Atlanta, GA, 30339, United States of America<br />

1 - A Pickup and Delivery Problem using Crossdocks and<br />

Truckload Lane Rates<br />

Kathleen Lindsey, Georgia Institute of Technology, Atlanta, GA,<br />

United States of America, kate.abercrombie@gatech.edu,<br />

Alan Erera, Martin Savelsbergh<br />

A path-based integer programming model is presented for a shipper pickup and<br />

delivery planning problem to move freight from origins to destinations. Each<br />

shipment is moved either direct via a less-than-truckload (LTL) carrier or<br />

consolidated with other shipments and moved by truckload routes. When using a<br />

truckload carrier, the shipper takes advantage of contracted lane rates that are<br />

significantly less than comparable LTL prices for a full truckload. For larger<br />

instances that cannot be directly solved using commercial solvers, an IP-based<br />

local search approach is developed.<br />

2 - A Network Flow Methodology to Estimate Empty Trips in Freight<br />

Transportation Models<br />

Satish Ukkusuri, Associate Professor, Purdue University, 550<br />

Stadium Mall Drive, G175F, West Lafayette, IN, 47906, United<br />

States of America, sukkusur@purdue.edu, Rodrigo Mesa-Arango<br />

This research presents a novel methodology to estimate the number of empty<br />

trips useful for regional freight planning. This methodology is based on a time<br />

expanded network flow approach that captures behavioral and operational characteristics<br />

of the carriers. The model is formulated as a linear optimization problem<br />

that minimizes the system costs associated to truck trips. The model is validated<br />

with a commercial vehicle survey from Colombia.<br />

3 - Sugarcane Harvest Logistics in Brazil<br />

Kamal Lamsal, University of Iowa, 108 Pappajohn Business Bldg,<br />

S210, Iowa City, IA, 52242, United States of America,<br />

kamal-lamsal@uiowa.edu, Barrett W. Thomas, Philip Jones<br />

In the face of rising world sugar prices, the logistics of sugar mills in the Brazil,<br />

the world’s largest sugar producer, are of great interest. In this presentation, we<br />

present a rolling horizon approach to coordinating sugarcane harvest operations<br />

for Brazilian sugar mills. After each random event, we update an integer program<br />

to account for both new information and operations already underway. The<br />

solutions from our dynamic approach are compared to a perfect information<br />

bound.<br />

INFORMS Phoenix – 2012<br />

147<br />

4 - Customer Order Rationing in Shipment Consolidation<br />

Benhür Satir, Assistant Professor, Cankaya University,<br />

Yenimahalle, Ankara, 06810, Turkey, benhur@cankaya.edu.tr,<br />

James Bookbinder, Fatih Safa Erenay<br />

A delivery company faces two classes of demand for dispatching a single package<br />

type, viz. standard and express; the latter is more profitable. Shipments are made<br />

by capacitated vehicles. The optimal customer rationing policy for shipment<br />

consolidation is modeled and solved as a continuous-time Markov Decision<br />

Process.<br />

■ SD49<br />

SD49<br />

49- North 231 B- CC<br />

Public Transit: Network Modeling<br />

Sponsor: Transportation Science & Logistics<br />

Sponsored Session<br />

Chair: Wei Fan, Associate Professor, The University of Texas at Tyler,<br />

Department of Civil Engineering, 3900 University Blvd, Tyler, TX,<br />

75799, United States of America, wfan@uttyler.edu<br />

1 - Spatial and Temporal Tradeoffs in Transit Stop Location<br />

Problems<br />

Sha Mamun, Graduate Student, University of Conneticut, 261<br />

Glenbrook Road, Unit 2037, Storrs, CT, 06269, United States of<br />

America, msm08014@engr.uconn.edu, Nicholas Lownes<br />

A transit network design problem is presented to optimize transit service<br />

efficiency by adjusting service frequency and transit stop locations. A bi-level<br />

mathematical programming model is constructed to allow tradeoffs between the<br />

spatial design (stop location) and the temporal operations (frequency setting). The<br />

stop locations are optimized by minimizing the cost components in the lower<br />

level, while the upper level optimized the transit line frequencies by maximizing<br />

network connectivity.<br />

2 - Trade-offs in Bus Frequency Allocation: System Level<br />

Optimization and Application to Large Scale Network<br />

Omer I. Verbas, Northwestern University, Evanston, IL, 60208,<br />

United States of America, ismailverbas2012@u.northwestern.edu,<br />

Hani S. Mahmassani<br />

We present a system-level model for frequency allocation to bus routes. The<br />

formulation solves for optimal frequencies that vary throughout the course of the<br />

day on individual routes and associated service patterns. Objectives include<br />

ridership maximization, waiting time minimization and cost minimization, subject<br />

to fleet and crowding considerations. Detailed demand elasticity levels are used in<br />

an application to the Chicago area network.<br />

3 - Equitable Redesign of the Existing Public Transit Route<br />

Networks: A Bi-level Optimization Approach<br />

Wei Fan, Associate Professor, The University of Texas at Tyler,<br />

Department of Civil Engineering, 3900 University Blvd, Tyler, TX,<br />

75799, United States of America, wfan@uttyler.edu<br />

A bi-level optimization model is formulated, which can explicitly account for the<br />

spatial equity, for solving the public transit route network redesign problem<br />

(PTNRP). A genetic algorithm based solution approach is developed to solving this<br />

PTNRP bi-level optimization model. Network experiments are conducted.<br />

Numerical results and related characteristics are also described in detail.<br />

4 - A Simulation-based Transit Assignment Model<br />

Mark Hickman, Associate Professor, University of Arizona, 1209 E.<br />

Second Street, Tucson, AZ, 85721-0072, United States of America,<br />

mhickman@email.arizona.edu, Alireza Khani<br />

In the context of a scheduled fixed-route transit service, we explore a more<br />

realistic passenger assignment using an integrated traffic and transit simulation<br />

tool to generate transit vehicle trajectories. Using these trajectories, we assign<br />

transit passengers to the network using either a trip-based shortest path or a tripbased<br />

hyperpath assignment. The simulation model and the associated transit<br />

assignment methods are illustrated on a case study from Sacramento, California.


SD50<br />

■ SD50<br />

50- North 231 C- CC<br />

Military Search and Surveillance<br />

Sponsor: Military Applications<br />

Sponsored Session<br />

Chair: Michael Hirsch, Raytheon Company, Orlando, FL,<br />

United States of America, mjh8787@ufl.edu<br />

1 - Hunting Drug Smugglers: An Optimal Search Problem in<br />

Continuous Time and Space<br />

Jesse Pietz, Naval Postgraduate School, 1411 Cunningham Road,<br />

Monterey, CA, United States of America, japietz@nps.edu,<br />

Johannes Royset<br />

We consider search for moving targets in continuous time and space, and<br />

formulate a mixed-integer nonlinear program whose solution yields an optimal<br />

search plan. We highlight features of this highly challenging problem that lead to<br />

specialized algorithms and discuss solutions for application to drug smuggling<br />

interdiction operations.<br />

2 - Optimal Search for a Random Moving Intruder<br />

David Casbeer, Air Force Research Lab., AFRL/RBCA, B146 R300,<br />

WPAFB, OH, 45433, United States of America,<br />

David.Casbeer@wpafb.af.mil, Meir Pachter, K. Krishnamoorthy,<br />

Phillip Chandler<br />

Using reachability arguments, the optimal control of an agent searching for an<br />

intruder on a graph is considered. The agent is only able to perceive partial and<br />

delayed information about the intruder. Sufficient conditions for guaranteed<br />

isolation of the intruder, before he reaches his goal, and the corresponding<br />

optimal agent control policy, are provided.<br />

3 - A Joint Surveillance and Patrol Problem for Law Enforcement<br />

Belleh Fontem, PhD Candidate, The University of Alabama, 300<br />

Alston Hall, 361 Stadium Drive, Tuscaloosa, AL, 35487, United<br />

States of America, bafontem@crimson.ua.edu, Sharif Melouk,<br />

Burcu Keskin<br />

We investigate the problem of using unmanned aerial systems (UASs) as visual<br />

aids to ground law enforcement agents while assigning dangerous incidents to<br />

these agents in order to maximize the cumulative harm averted to society. We<br />

introduce a very tight formulation of the resulting team orienteering problem and<br />

and draw insights from theoretical analyses as well as from numerical<br />

experiments.<br />

■ SD51<br />

51- North 232 A- CC<br />

Joint Session MAS/SPPSN:Defense Operations and<br />

Homeland Security II<br />

Sponsor: Military Applications & Public Programs, Service and<br />

Needs<br />

Sponsored Session<br />

Chair: Anna Doro-on, Sr. Consultant/Project Engineer, Water, Tunnel &<br />

Infrastructure Concepts, Inc., 120 S. Euclid Avenue, Pasadena, CA,<br />

91101, United States of America, anna@annaforhomelandsecurity.com<br />

1 - Terror Queues and the Duration of Terror Plots<br />

Edward Kaplan, William N. and Marie A. Beach Professor of<br />

Management Sciences, Yale School of Management, 135 Prospect<br />

Street, New Haven, CT, 06520, United States of America,<br />

edward.kaplan@yale.edu<br />

Starting with a review of US terrorism-related indictments, lower and upper<br />

bounds for the initiation date of 30 distinct Jihadi plots were identified in addition<br />

to the date of arrest or an attempted/actual terror act. Estimated mean duration<br />

equals 9 months, while 95% of all plots are estimated to fall between 1 and 25<br />

months. These estimates suggest that in the United States, on average<br />

approximately three ongoing Jihadi terror plots have been active at any point in<br />

time since 9/11/2001.<br />

2 - Intelligent-IEDs Application and Risk Acceptability Optimization<br />

in a Successful Conduct of War<br />

Anna Doro-on, Sr. Consultant/Project Engineer, Water, Tunnel &<br />

Infrastructure Concepts, Inc., 120 S. Euclid Avenue, Pasadena, CA,<br />

91101, United States of America,<br />

anna@annaforhomelandsecurity.com<br />

The Improvised Explosive Devices (IEDs) were used by terrorists against United<br />

States and Allies’ military forces and responsible of deaths in Iraq and<br />

Afghanistan. This paper presents the application of intelligent-IEDs for the<br />

INFORMS Phoenix – 2012<br />

148<br />

effectiveness of military operations and defense against the enemy, to decrease<br />

military casualties, protect infrastructures, minimize risk of terrorism, and<br />

maximize risk acceptability.<br />

3 - Finding Fakes: Counterfeit Product Detection at United States<br />

Border Crossings<br />

Gregory DeYong, Assistant Professor, University of Michigan-Flint,<br />

2145 Riverfront Center, 303 E. Kearsley Street, Flint, MI, 48502,<br />

United States of America, gdeyong@umflint.edu<br />

The problem of counterfeit products continues to plague manufacturers. Using<br />

data from the U.S. Customs and Border Patrol, we analyze the effectiveness of<br />

border crossing points using data envelopment analysis and apply game theory to<br />

suggest interdiction strategies.<br />

4 - Optimal Placement of Multiple Types of Detectors under a Small<br />

Vessel Attack Threat to Port Security<br />

Xiaofeng Nie, Assistant Professor, Nanyang Technological<br />

University, 50 Nanyang Avenue, Singapore, 639798, Singapore,<br />

xiaofengnie@ntu.edu.sg, Xihong Yan<br />

Because of the strategic importance, ports are potential terrorist targets. We focus<br />

on the threat scenario where the terrorists would use small vessels as waterborne<br />

improvised explosive devices to attack maritime targets. We consider how to<br />

locate multiple types of detectors such that the expected damage cost is<br />

minimized. The model is formulated as a nonlinear binary integer program and<br />

some exact and heuristic algorithms are proposed.<br />

■ SD52<br />

52- North 232 B- CC<br />

Optimization in Smart Grid<br />

Sponsor: Energy, Natural Res & the Environment/Energy<br />

Sponsored Session<br />

Chair: Andrew Liu, Assistant Professor, Purdue University, 315 N. Grant<br />

Street, West Lafayette, IN, 47907, United States of America,<br />

andrewliu@purdue.edu<br />

1 - Decision Making in the Operation of Smart Distribution Systems<br />

Mingguo Hong, Midwest ISO, 5407 Alvamar Place, Carmel, IN,<br />

46033, United States of America, mingguoh@hotmail.com<br />

The Smart Grid operation involves both the eletrical transmission and distribution<br />

systems where infrastructure and operational strategy changes should take place<br />

in parallel. This talk focuses on the operational decisions of the Smart Grid at the<br />

distribution system level to ensure greater grid reliability and economic efficiency.<br />

The talk also looks at a potential market design for the distribution system<br />

involving electrical utility and their customers.<br />

2 - Quantify Effects of Home Energy Management System under<br />

Dynamic Electricity Pricing<br />

Jingjie Xiao, PhD Candidate, Purdue University, 315 N. Grant<br />

Street, West Lafayette, IN, 47907, United States of America,<br />

jingjie.xiao@gmail.com, Andrew Liu, Joseph F. Pekny<br />

A key hurdle for implementing real-time pricing of electricity is the lack of<br />

consumers’ responses. Solutions to overcome the hurdle include energy<br />

management systems that can automatically optimize household appliance usage<br />

and PHEV charging via two-way communication with the utilities (or the grid).<br />

This talk will show how the optimization can be done and how such systems can<br />

be integrated with electricity markets’ operation under various uncertainties<br />

through approximate dynamic programming.<br />

3 - SMART-ISO: A Stochastic, Multiscale Model of the<br />

PJM Power Grid<br />

Warren Powell, Princeton University, 230 Sherrerd Hall, Princeton,<br />

NJ, 08544, United States of America, powell@princeton.edu,<br />

Boris Defourny, Hugo Simao<br />

We will describe the development of a stochastic, multiscale, dynamic model of<br />

the PJM power grid. SMART-ISO includes a full model of the PJM power grid, a<br />

robust day-ahead model for stochastic unit commitment, hour-ahead modeling<br />

for planning natural gas simulation, and economic dispatch solved at five minute<br />

increments for accurate modeling of ramp rates of natural gas units and variations<br />

in renewables. We report on the status of this multi-year development effort.<br />

4 - Dynamic Stability of Electricity Markets<br />

Victor Zavala, Argonne National Laboratory, Mathematics &<br />

Computer Science Division, Chicago, IL, 60439,<br />

United States of America, vzavala@mcs.anl.gov<br />

We present new insights on the dynamic stability of markets. We discuss how<br />

stability issues arise from incomplete gaming and physical constraints and propose<br />

strategies to mitigate these.


■ SD53<br />

53- North 232 C- CC<br />

Optimization Models for Demand-Response<br />

Sponsor: Energy, Natural Res & the Environment/Energy<br />

Sponsored Session<br />

Chair: Miguel F. Anjos, Canada Research Chair in Discrete Nonlinear<br />

Optimization in Engineering, Ecole Polytechnique de Montreal, C.P.<br />

6079, succ. Centre-ville, Montreal, QC, H3C 3A7, Canada,<br />

miguel-f.anjos@polymtl.ca<br />

1 - Real-time Demand Response Model<br />

Antonio Conejo, Professor, Universidad Castilla-La Mancha,<br />

Campus Universitario, Ciudad Real, 13071, Spain,<br />

Antonio.Conejo@uclm.es, Luis Baringo, Juan Miguel Morales<br />

This presentation describes an optimization model to adjust the hourly load level<br />

of a given consumer in response to electricity prices. The objective of the model is<br />

to maximize the consumer utility. Price uncertainty is modeled through robust<br />

optimization techniques. The model materializes into a simple LP that can be<br />

integrated in the Energy Management System of a household or a small business.<br />

A simple bi-directional communication device enables the implementation of the<br />

proposed model.<br />

2 - Demand Response in the California ISO market<br />

Guillermo Bautista Alderete, Manager of Market Validation and<br />

Quality Analysis, California ISO, 250 Outcropping Way,<br />

Folsom, CA, 95630, United States of America,<br />

bautista.guillermo@gmail.com<br />

This presentation explains the initiatives and mechanisms in place to facilitate the<br />

participation of retail demand response programs in the California ISO wholesale<br />

market, including the implementation of a new demand response product known<br />

as the proxy demand resource. In conjunction with the ISO’s existing<br />

participating load product, the proxy demand resource product will add to the<br />

demand response capability available to market participants.<br />

3 - Optimization for Time-of-use Control in Electricity Demand<br />

Side Management<br />

David F. Rogers, Associate Professor of Operations and Business<br />

Analytics, University of Cincinnati, 2925 Campus Green Dr, 531<br />

Carl H. Lindner Hall, Cincinnati, OH, 45221-0130,<br />

United States of America, David.Rogers@UC.edu, George G. Polak<br />

Time-of-use pricing of electricity in demand side management requires<br />

determining the time periods of a day that should be grouped for identical pricing.<br />

Integer & constraint programming models to find clusters of contiguous periods<br />

potentially with a “wrap-around” feature for which time periods at both the<br />

beginning and end of the day may be in the same cluster are examined. A realworld<br />

data set consisting of kwh usage for 93 buildings was employed for testing<br />

the models.<br />

4 - A System Architecture for Autonomous Demand Side Load<br />

Management in Smart Buildings<br />

Miguel F. Anjos, Canada Research Chair in Discrete Nonlinear<br />

Optimization in Engineering, Ecole Polytechnique de Montreal,<br />

C.P. 6079, succ. Centre-ville, Montreal, QC, H3C 3A7, Canada,<br />

miguel-f.anjos@polymtl.ca, Giuseppe T Costanzo, Gilles Savard,<br />

Guchuan Zhu<br />

We present a new system architecture for demand-side load management. The<br />

system is composed of modules for admission control, load balancing, and<br />

demand/response management that operate using online operation control,<br />

optimal scheduling, and dynamic pricing respectively. It can integrate different<br />

energy sources and handle autonomous systems with heterogeneous dynamics in<br />

multiple time-scales. Simulation results confirm the viability and efficiency of the<br />

proposed framework.<br />

INFORMS Phoenix – 2012<br />

149<br />

ENRE Poster Session<br />

ENRE POSTER SESSION<br />

North Building Foyer<br />

Cluster: ENRE Poster<br />

Invited Session<br />

Chair: Juan Pablo Vielma, University of Pittsburgh, 1043<br />

Benedum Hall, 3700 O’Hare Street, Pittsburgh, PA, 15261,<br />

United States of America, jvielma@pitt.edu<br />

1 - Competitive Markov Decision Process Model for<br />

Energy-water-climate Change Nexus<br />

Ivan Savedra, Research Assistant, University of Wisconsin-<br />

Milwaukee, 3200 North Cramer Street, Milwauke WI 53211,<br />

United States of America, saavedr9@uwm.edu,Vishnuteja Nanduri<br />

Drought-like conditions brought on by climate change are causing water shortages<br />

leading to power disruptions in many regions in the world. It is noted by<br />

the DOE that U.S. electricity industry uses more water for electricity production<br />

than the entire agricultural and horticultural industries combined. Energy-waterclimate<br />

change nexus is a critical issue that needs to be addressed. However,<br />

there are no existing quantitative models that examine this nexus. Our paper<br />

addresses this challenge.<br />

2 - Investigating through the Effects of Renewable Energy<br />

Technologies Exploitation on Economic Growth<br />

Seyed Hadi Nourbakhsh, University of Tehran, No 370,<br />

66 Alley, Dardash St.,Narmak, Tehran, Iran,<br />

hadi.noorbakhsh@gmail.com, Setareh Ariafar, Hessam Kazari<br />

In this research we tried to survey the effect of utilizing renewable energy technologies<br />

in electricity generation on economic growth by benefiting from a system<br />

dynamics approach. At first, we designed a causal model with considering<br />

main exogenous energy systems variables and economic variables. Then we executed<br />

proposed model for the case of Iran.<br />

3 - Modeling Investment Planning in Thermal Power Generation in<br />

India using Optimal Control Methods<br />

Sudhakar Achath, Professor, Amrita School of Business,<br />

Amrita Vishwa Vidyapeetham, Coimbatore, TN, 641112, India,<br />

s.m.achath@gmail.com<br />

Using linear quadratic control with learning, this study formulates an optimal<br />

plan for investments in plant capacity, R&D expenditure and imported technology<br />

for the Indian thermal power sector. The modelling system has twelve linear<br />

equations and the control problem formulated in state-space is solved as a<br />

dynamic programming problem using Lagrange multipliers and a backward solution<br />

method, following Chow (1975). The problem was initially written in BASIC<br />

but later resolved in open-source R.<br />

4 - Multi-objective Retrospective Optimization using<br />

Zigzag Search<br />

Honggang Wang, Rutgers University, 212 CoRE Building,<br />

Busch Campus, Rutgers, Piscataway, NJ, 08854,<br />

United States of America, honggang.w@rutgers.edu<br />

We propose a new retrospective optimization (RO) method with a gradient-based<br />

zigzag search approach for multi-objective simulation optimization (MOSO)problems.<br />

In the context of MOSO, a stochastic zigzag search algorithm is used in the<br />

RO framework. Numerical results of applying this new algorithm to MOSO problems<br />

will be provided.<br />

5 - Optimization for Annual Unloading Arrangement and Inventory<br />

Management in LNG Receiving Terminals<br />

Hidetaka Shinozaki, Tokyo Gas Co.,Ltd., 5-20, Kaigan 1-Chome,<br />

Minato-Ku, Tokyo, 1058527, Japan, shinozaki@tokyo-gas.co.jp,<br />

Shinnosuke Kimura, Hiroshi Kashio, Yohei Nakai, Mariko Ito,<br />

Shirou Morimitsu, Kazuaki Nagai<br />

We receive over 300 LNG vessels annually. The operators not only allocate the<br />

vessels to 3 terminals but also manage the inventory of 52 LNG tanks considering<br />

many constraints related to stocks, calorific values and so on. Besides, we have to<br />

reschedule the plan whenever some changes by shipping delay or demand fluctuations<br />

occur. We optimized annual unloading arrangement and inventory<br />

management in LNG receiving terminals. It enables to reduce the manpower and<br />

the operating cost.<br />

6 - Optimizing Batteries in Electricity Markets<br />

Eugene Zak, Viridity Energy, 2370 130 Ave., NE, #104, Bellevue,<br />

WA, United States of America, ezak@viridityenergy.com,<br />

Ricardo Rios-Zalapa<br />

Battery can operate as a generator, load, or storage. The problem is how to integrate<br />

the battery into the grid given its life cycle characteristics, functional flexibility,<br />

and electricity market conditions. We propose a model to optimize battery<br />

use for energy and regulation. The model takes advantage of a price difference<br />

between distinct time periods and alternative products and services. As a result<br />

the model delivers a charge-discharge strategy and its impact on the battery life.


ENRE POSTER SESSION<br />

7 - Payment Uncertainty Management in a Combined Market of<br />

Energy and Reserve<br />

Taísa Felix, Instituto Federal de Brasília, Quadra SHCGN 703<br />

Bloco L, Apartamento 103, Brasilia, DF, 70730-712, Brazil,<br />

taisa.felix@ifb.edu.br, Pablo Cuervo<br />

As a rule, power system markets operate considering bid cost minimization<br />

(BCM) in clearing processes. This procedure has inconsistency because the total<br />

BCM is different from the load payment. This work introduce a combined market<br />

model of energy and reserve operating under Payment Minimization (PM),<br />

transforming the problem in a bi-level linear model, which can be solved using<br />

GAMS®. Expected payment is evaluated using Monte Carlo simulation, providing<br />

results to evaluate the PM energy policy.<br />

8 - Transmission Expansion Planning using a Linearized<br />

AC Model<br />

Hui Zhang, Arizona State University, 5th floor, Room 519,<br />

551 E. Tyler Mall, Tempe, AZ, 85281, United States of America,<br />

dahui911@hotmail.com, Vijay Vittal, Gerald Heydt<br />

This paper presents a MILP approach for solving transmission expansion planning<br />

(TEP) problems using a linearized AC model. Compared to existing DCbased<br />

TEP models, the proposed model includes reactive power, off-nominal bus<br />

voltage magnitudes as well as network losses. A practical approach to include the<br />

N – 1 criterion is also discussed. The simulation results show that the proposed<br />

TEP model has better accuracy and is applicable to solve TEP problems for large<br />

power systems.<br />

■ SD54<br />

54- Regency Ballroom A- Hyatt<br />

Feature Articles from Recent Issues of INFORMS<br />

Transactions on Education (ITE) and Discussion of<br />

the ITE Review & Publication Process<br />

Cluster: INFORMS Journals Cluster<br />

Invited Session<br />

Chair: James Cochran, Bank of Ruston Endowed Research Professor,<br />

Louisiana Tech University, College of Business, Ruston, 71272318 2,<br />

United States of America, jcochran@latech.edu<br />

Co-Chair: Matthew Bailey, Associate Professor, Bucknell University,<br />

School of Management, Lewisburg, PA, 17837,<br />

United States of America, matt.bailey@bucknell.edu<br />

Co-Chair: Vijay Mehrotra, University of San Francisco, School of<br />

Management, 2130 Fulton Street, San Francisco, CA,<br />

United States of America, vmehrotra@usfca.edu<br />

Co-Chair: Armann Ingolfsson, Dr., University of Alberta, School of<br />

Business, University of Alberta, Edmonton, AB, T6G 2R6, Canada,<br />

armann.ingolfsson@business.ualberta.ca<br />

Co-Chair: Jill Hardin Wilson, Northwestern University IEMS, 2145<br />

Sheridan Rd, Room C210, Evanston, IL, 60208,<br />

United States of America, jill.wilson@northwestern.edu<br />

1 - The Effectiveness of using a Web-based Applet to Teach<br />

Concepts of Linear Programming<br />

Christine Kydd, Professor, University of Delaware, Department of<br />

Business Administration, Lerner College of Business, Newark, DE,<br />

19716, United States of America, chriskyd@udel.edu<br />

This paper presents a web-based java applet that was used by instructors and<br />

students to graphically illustrate/learn fundamental concepts of LP models. It<br />

describes the results of a study which compares student performance of those<br />

who did use the applet vs. those who did not. Results show that the students who<br />

used the applet to learn about LP concepts performed significantly better than<br />

those who did not. Implications for using such techniques in the classroom are<br />

discussed.<br />

2 - Active Learning Exercises for a Service Operations<br />

Management Course<br />

Mark Davis, Professor, Bentley University, 175 Forest St.,<br />

Waltham, MA, 02452, United States of America,<br />

mdavis@bentley.edu, Ravi Behara<br />

In today’s hi-tech environment, students are familiar with the Internet where<br />

they actively participate in the generation and consumption of information. Thus,<br />

if business schools want to stimulate student interest, they have to actively<br />

engage them in the learning process. This presentation introduces exercises, some<br />

of which are part of the course structure, that incorporate active learning in the<br />

classroom, and which align well with topics that are in a service operations<br />

management course.<br />

INFORMS Phoenix – 2012<br />

150<br />

3 - Case Article: Flight Delays at RegionEx<br />

Susan Martonosi, Harvey Mudd College, Department of<br />

Mathematics, Claremont, CA, United States of America,<br />

martonosi@hmc.edu, Amr Farahat<br />

In this case about two fictitious airlines, RegionEx, a small regional airline, is a<br />

contracted regional carrier for MDA, a major US airline. RegionEx is at risk of<br />

losing its contract due to an apparently poor flight delay record, and the Flight<br />

Operations Manager must analyze the flight delay records and explain RegionEx’s<br />

seemingly poor performance. Undergraduate and MBA students use basic data<br />

analysis techniques to discover important paradoxes in the flight delay data.<br />

4 - KEY Electronics - Sourcing and Warehouse Analysis<br />

Tim Kraft, University of Virginia, Darden School of Business,<br />

Charlottesville, VA, 22902, United States of America,<br />

kraftt@darden.virginia.edu, Yenho Chung, Feryal Erhun<br />

KEY Electronics is a consumer electronics retailer that generated $1.4 billion in<br />

total revenue in 2008. KEY has a limited retail presence in Mexico, which it<br />

would like to expand. As part of its growth strategy, KEY must (1) improve its<br />

current sourcing of products for Mexico and (2) revamp its existing warehouse<br />

operations. KEY introduces students to a practical inventory modeling scenario<br />

with real-life data, where solutions are not solely based on minimum cost but also<br />

qualitative factors.<br />

■ SD55<br />

55- Regency Ballroom B - Hyatt<br />

Operations Research and†Management Science in<br />

Emerging Economies<br />

Cluster: Operations Research in Emerging Economies<br />

Invited Session<br />

Chair: Siddhartha SenGupta, Principal Scientist, Tata Consultancy<br />

Services Ltd, Gateway Park, 2nd flr, MIDC Road 13, MIDC, Andheri<br />

East, Mumbai, Ma, 400093, India, Siddhartha.SenGupta@tcs.com<br />

1 - Rationing Policy and Inventory Optimization Models for a<br />

Three-Stage Divergent Supply Chain<br />

Chandrasekharan Rajendran, Professor, IIT Madras, Chennai,<br />

600 036, India, craj@iitm.ac.in, Kurian John, Brijesh Paul<br />

This work considers a static three-stage divergent supply chain model consisting<br />

of retailers, two distributors and one manufacturer. A distributor serves only a<br />

subset of retailers for whom she/he is the sole supplier. The unsatisfied demands<br />

at all the installations are backordered. Assuming the base-stock policy, the<br />

objective is to determine the best installation inventory order policy parameters<br />

such as the base-stock levels and inventory rationing quantities, with the<br />

objective of minimizing the total supply chain cost (TSCC) consisting of holding<br />

costs and shortage costs at all installations in the supply chain over a finite<br />

planning horizon. An integer programming model to determine the optimal<br />

inventory control-policy parameters is proposed in this work. Computational<br />

complexity limits the applicability of the exact solution method to large problem<br />

sizes. Therefore, in the current study we also propose a hybrid heuristic technique<br />

based on Genetic Algorithm (GA) and Particle Swarm optimization (PSO)<br />

algorithm to determine the best base-stock levels. A heuristic rationing rule<br />

determines the shipment (rationing) quantity in the case of shortage at a higher<br />

installation, while meeting the customer demands. The performance of the hybrid<br />

heuristic against the stand-alone GA and PSO is ascertained by testing the<br />

algorithms under various supply chain settings.<br />

2 - A Rough Set-decision Tree Based Approach for Design of<br />

Optimal Process Tolerances<br />

J Maiti, Associate Professor, Indian Institute of Technology<br />

Kharagpur, Industrial Engineering and Management, Kharagpur,<br />

India, jmaiti@iem.iitkgp.ernet.in, Sandipan Karmakar<br />

Tolerance design provides a leeway to counteract the inherent manufacturing<br />

uncertainties with desired product performance. It is important to design<br />

tolerances on process elements based on product dimensions. In this study, the<br />

authors propose a novel approach using rough set theory-decision tree to find out<br />

the best tolerance values on process elements. A example of an assembly of sheet<br />

metals for automotive body assembly is discussed to show the effectiveness of the<br />

proposed method.


3 - Business Models and Processes for 3PL Providers<br />

Siddhartha SenGupta, Principal Scientist, Tata Consultancy<br />

Services Ltd, Gateway Park, 2nd flr, MIDC Road 13, MIDC,<br />

Andheri East, Mumbai, Ma, 400093, India,<br />

Siddhartha.SenGupta@tcs.com<br />

Economically Services are becoming increasingly more important and it would be<br />

useful to develop appropriate Business Models and Business Processes for service<br />

value chains. Here we try to “Learn from the smokestacks” - from the well<br />

developed Models and Processes of Manufacturing. In particular, we find that the<br />

IHIP characteristics of Services make them similar to manufacturing models<br />

where the decoupling point is away from the customer processes, e.g. in Make-<br />

To-Order. We adapt and extend the relevant methods of these models to 3PL<br />

services, especially to shipping.<br />

4 - Food Security for Emerging Economies – An OR Perspective<br />

G Raghuram, Professor, Indian Institute of Management<br />

Ahmedabad, Wing 15, IIMA Campus, IIMA Campus, Ahmedabad,<br />

380015, India, graghu@iimahd.ernet.in, Ankan Pal<br />

Food security is provided by the Food Corporation of India which procured 50<br />

million tons of food grains in 2011-12 with a spend of over Rs 80,000 crores.<br />

Towards achieving this, the primary activity is managing logistics, including the<br />

type of storage (bulk/bagged, covered/open, own/outsourced), allocation from<br />

procurement to storage to demand points, mode choice, and quality<br />

management. This paper provides a perspective on OR methods which can help<br />

achieve food security while optimizing costs.<br />

■ SD56<br />

56- Curtis A- Hyatt<br />

Entrepreneurship and Innovation II<br />

Sponsor: Technology Management<br />

Sponsored Session<br />

Chair: Sinan Erzurumlu, Assistant Professor, Babson College,<br />

231 Forest Park, Babson Park, MA, 02457, United States of America,<br />

serzurumlu@babson.edu<br />

1 - Strategies for Profiting from Technologies with Weak<br />

Patent Rights<br />

Leonardo Santiago, Federal University of Minas Gerais, Escola de<br />

Engenharia da UFMG, Av. Antonio Carlos, 6627. Pampulha,<br />

Belo Horizonte, MG, 31270-901, Brazil, lsantiago@ufmg.br,<br />

Henrique Rocha<br />

We investigate a set of strategies that companies adopt in order to profit from<br />

innovations. The strategies depend not only on inherent features of the<br />

innovation at stake but also on the incentives potential competitors have to enter<br />

in the target market. Our main focus is on technologies characterized by weak<br />

patent rights.<br />

2 - Management of Innovation in the Product and<br />

Technology Markets<br />

Sinan Erzurumlu, Assistant Professor, Babson College, 231 Forest<br />

Park, Babson Park, MA, 02457, United States of America,<br />

serzurumlu@babson.edu, Karthik Ramachandran<br />

Firms in many technology intensive industries increasingly license innovations to<br />

potential competitors besides using them in their own products. Licensing not<br />

only creates an additional profit stream, but could also enhance the value of the<br />

innovator’s own product. However, it also makes the licensee a potent competitor<br />

in the product market. In this paper, we develop a model to understand if, when<br />

and how a firm should share its innovation with a rival.<br />

3 - Value of Reverse Factoring in Multi-stage Supply Chains<br />

Fehmi Tanrisever, Eindhoven University of Technology, Den<br />

Dolech 2, Eindhoven, 5612, Netherlands, f.tanrisever@tue.nl,<br />

Hande Cetinay, Matthew Reindorp<br />

We develop a mathematical model for integration, analysis, and optimization of<br />

operational and financial processes within a supply chain. Specifically, we<br />

consider commercial transactions of a large corporate customer with a small- or<br />

medium-sized supplier. We show how application of reverse factoring – an<br />

increasingly popular product within the broad field of supply chain finance –<br />

influences the operational and financial decisions of these firms.<br />

INFORMS Phoenix – 2012<br />

151<br />

4 - A Dynamic Model of Knowledge Creation from Exploration and<br />

Exploitation in the High-tech Venture<br />

Jennifer Bailey, Georgia Institute of Technology, 800 W. Peachtree<br />

Road, NW, Atlanta, GA, United States of America,<br />

Jennifer.Bailey@mgt.gatech.edu, Cheryl Gaimon<br />

We develop a dynamic model of exploration and exploitation for a high-tech<br />

venture. The uncertain nature of these learning activities is captured in terms of<br />

the mean and variance of the innovation outcomes. We consider the impact of<br />

the venture’s absorptive capacity as well as the lagged effect of exploration on<br />

innovation outcomes. We determine when the typical explore-exploit versus an<br />

atypical exploit-explore sequential strategy is optimal.<br />

■ SD57<br />

57- Curtis B- Hyatt<br />

Applications of Queueing Models<br />

Contributed Session<br />

SD57<br />

Chair: Jun Luo, Hong Kong University of Science and Technology, Rm<br />

5567, Academic Building, Clear Water Bay, Hong Kong, Hong Kong -<br />

PRC, jluolawren@ust.hk<br />

1 - Modeling Sequential Zone Picking Systems<br />

Jelmer van der Gaast, Erasmus University, Burgemeester Oudlaan<br />

50, Rotterdam, Netherlands, jgaast@rsm.nl, René De Koster,<br />

Ivo Adan, Jacques Resing<br />

We develop an analytical model for analyzing sequential zone picking systems.<br />

The system is approximated by a multi-class product-form closed queueing<br />

network with jump-over blocking. An iterative algorithm using mean value<br />

analysis (MVA) is used to evaluate the performance statistics of the order picking<br />

system. The accuracy of the algorithm is compared with this results of a discrete<br />

event simulation.<br />

2 - A Simple, Practical Prioritization Scheme to Minimize Cycle<br />

Time and Maximize Throughput<br />

Shuping Zhang, University of Tennessee, Knoxville,<br />

201 Stokely Management Center, Knoxville, TN, 37996,<br />

United States of America, szhang12@utk.edu<br />

The MRO process is used to recondition equipment in the railroad, off-shore<br />

drilling, aircraft, and shipping industries. We model the back-shop as a multi-class<br />

queueing network with a ConWIP execution system and introduce a new priority<br />

scheme to maximize system performance. Simulation results show that this<br />

priority scheme increases system performance by lowering average cycle times<br />

without dramatically impacting total throughput.<br />

3 - Optimal Staffing for Ticket Queues<br />

Li Xiao, Business School, National University of Singapore, Biz 2<br />

Building, Basement B2-03, NUS, singapore, Singapore,<br />

a0075548@nus.edu.sg, Susan Xu, Hanqin Zhang<br />

This talk is concerned with ticket queues systems, where each arriving customer<br />

gets in the system with a numbered ticket and observes the number of working<br />

servers. The arriving customers abandon the system with some probability<br />

determined by the number of working servers. The system cost includes customer<br />

abandonment and server operations costs. Based on the ticket number<br />

information, we address the question how to staff such that the expected longrun<br />

average cost is minimized.<br />

4 - Staffing and Control of an Instant-messaging Based Customer<br />

Service Center<br />

Jun Luo, Hong Kong University of Science and Technology,<br />

Rm 5567, Academic Building, Clear Water Bay, Hong Kong,<br />

Hong Kong-PRC, jluolawren@ust.hk, Jiheng Zhang<br />

A new kind of customer service centers, in which agents communicate with<br />

customers via instant-messaging (IM) on the Internet, is prevalent nowadays. A<br />

distinctive feature of IM-based service centers is that one agent can serve multiple<br />

customers in parallel. We model it as a server pool consisting of many limited<br />

processor sharing servers. The underlying stochastic processes can be<br />

characterized by a fluid approximation, which provides insights into the optimal<br />

staffing and control policies.


SD58<br />

■ SD58<br />

58- Phoenix East- Hyatt<br />

Asymptotics and Optimization of Queueing Systems<br />

Sponsor: Applied Probability<br />

Sponsored Session<br />

Chair: Hengqing Ye, Associate Professor, Hong Kong Polytechnic<br />

University, Kowloon, Hong Kong - PRC, lgtyehq@inet.polyu.edu.hk<br />

1 - Excursion-based Universal Approximations for the Erlang-A<br />

Queue in Steady-state<br />

Itai Gurvich, Northwestern University-Kellogg School of<br />

Management, Evanston, IL, United States of America,<br />

i-gurvich@kellogg.northwestern.edu, Junfei Huang,<br />

Avishai Mandelbaum<br />

We re-visit the Erlang-A queue and propose a universal diffusion approximation<br />

(rather than limit) that applies simultaneously to all of the existing many-server<br />

heavy-traffic regimes: QED, ED, QD and NDS. The approximation yields accurate<br />

estimates for steady-state metrics. In our proofs, we do not use the steady-state<br />

distribution of the Erlang-A queue. Rather, we relate the excursions of the<br />

underlying Birth-and-Death process to properly defined excursions of the<br />

universal diffusion.<br />

2 - Optimal Queue-size Scaling in Switched Networks<br />

Neil Walton, University of Amsterdam, Science Park 904,<br />

Amsterdam, 1098 XH, Netherlands, n.s.walton@uva.nl,<br />

Yuan Zhong, Devavrat Shah<br />

We consider a switched network with constraints on which queues may be served<br />

simultaneously; such networks have been used to effectively model input-queued<br />

switches. The scheduling policy for such a network specifies which queues to<br />

serve at any point in time, based on the current state or past history of the<br />

system. We provide a new class of online scheduling policies that achieve optimal<br />

average queue-size scaling for a class of switched networks including inputqueued<br />

switches.<br />

3 - Diffusion Limit of Fair Resource Control—Stationarity and<br />

Interchange of Limits<br />

Hengqing Ye, Associate Professor, Hong Kong Polytechnic<br />

University, Kowloon, Hong Kong-PRC,<br />

lgtyehq@inet.polyu.edu.hk, David Yao<br />

Consider a network in which each job requires the concurrent occupancy of a<br />

subset of servers, and the service capacity is shared among job classes following<br />

the proportional fair allocation. We demonstrate that the usual traffic condition of<br />

the diffusion limit is necessary and sufficient for both the diffusion limit and<br />

prelimit networks to have stationary distributions, and justify the diffusion<br />

approximation of the stationary distribution and p-th moment under a bounded<br />

workload condition.<br />

4 - Skill Based FCFS Service Systems<br />

Gideon Weiss, University of Haifa, Mount Carmel 31905, Haifa,<br />

Israel, gweiss@stat.haifa.ac.il, Ivo Adan<br />

We consider systems with several types of customers and several types of servers,<br />

where compatibility of servers to customers is given by a bipartite graph. This is<br />

motivated by call centers with skill based routing, and by organ transplant<br />

applications. A common approach is provided by infinite first come first served<br />

matching of two infinite multi-type random sequences. We obtain explicit results<br />

for this model, and approximations for many server queues with abandonments.<br />

■ SD59<br />

59- Phoenix West- Hyatt<br />

Stochastic Network Algorithms<br />

Sponsor: Applied Probability<br />

Sponsored Session<br />

Chair: Devavrat Shah, Massachusetts Institute of Technology, 32-D670,<br />

77 Massachusetts Ave, Cambridge, MA, 02139,<br />

United States of America, devavrat@mit.edu<br />

Chair: Yuan Zhong, Massachusetts Institute of Technology,<br />

235 Albany Street, Cambridge, MA, 02139, United States of America,<br />

zhyu4118@mit.edu<br />

1 - Dynamic Scheduling in Queueing Networks with Heavy-tailed<br />

Traffic: Insights through Fluid Models<br />

Mihalis Markakis, Massachusetts Institute of Technology,<br />

77 Massachusetts Avenue, 32D-666, Cambridge, MA, 02139,<br />

United States of America, mihalis@mit.edu, John N. Tsitsiklis,<br />

Eytan Modiano<br />

In this talk we present the first steps towards a systematic methodology for<br />

evaluating the performance of dynamic scheduling policies for switched queueing<br />

INFORMS Phoenix – 2012<br />

152<br />

networks under heavy-tailed traffic. We establish a connection between delay<br />

instability of queues and the evolution of the fluid model from certain initial<br />

conditions. This enables us to identify the delay unstable queues by simulating<br />

the fluid model. Moreover, it allows us to reach a surprising conclusion for special<br />

networks of interest.<br />

2 - A Note on Queue-size Scaling for Input-queued Switches<br />

Yuan Zhong, Massachusetts Institute of Technology, 235 Albany<br />

Street, Cambridge, MA, 02139, United States of America,<br />

zhyu4118@mit.edu, Devavrat Shah, John N. Tsitsiklis<br />

We consider queue-size scaling in an input-queued switch. In the main result of<br />

the paper, we provide a new class of scheduling policies under which the longrun<br />

average total queue size scales as power 2.5 of the port number n, in a certain<br />

limiting regime of interest. This is a substantial improvement upon prior works,<br />

where the same quantity scales as power 3 of n. Our result also advances toward<br />

a conjecture about optimal queue-size scaling in input-queued switches.<br />

3 - Smoothed Online Convex Optimization<br />

Adam Wierman, Assistant Professor, Caltech, 1200 E. California<br />

Blvd., Pasadena, CA, 91125, United States of America,<br />

adamw@caltech.edu, Lachlan Andrew, Minghong Lin,<br />

Alan Roytman<br />

Out work on sustainable data center design during the last few years has<br />

repeatedly led us to a class of problems we term “smoothed online convex<br />

optimization (SOCO)” problems. SOCO is a variant of the class of “online convex<br />

optimization (OCO)” problems, and is strongly related to the class of “metrical<br />

task systems”, each of which have been studied largely independently. In this talk<br />

I will discuss some recent progress toward unifying the results and algorithms<br />

from these communities.<br />

4 - The UFOS Algorithm for Network Resource Allocation<br />

Yang Yang, Graduate School of Business, Stanford University,<br />

W146A, Knight Management Center, 655 Knight Way,<br />

Stanford, CA, 94305, United States of America,<br />

yang.yang1025@stanford.edu, J. Michael Harrison,<br />

Chinmoy Mandayam<br />

The UFOS algorithm (utilization first, output second) puts primary emphasis on<br />

greedy maximization of total resource utilization, and secondary emphasis on<br />

greedy maximization of total outflow. Focusing on connection-level models of<br />

internet congestion control, we compare the delay-related performance of UFOS<br />

with that of proportionally fair (PF) resource allocation. In our simulation studies,<br />

UFOS reduces overall average delay by about 30% relative to PF.<br />

■ SD60<br />

60- Remington- Hyatt<br />

Air Transportation and High-Speed Rail: Competition<br />

and Cooperation<br />

Sponsor: Aviation Applications<br />

Sponsored Session<br />

Chair: Regina Clewlow, PhD Candidate, Massachusetts Institute of<br />

Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139,<br />

United States of America, rclewlow@alum.mit.edu<br />

1 - The Impact of Climate Policy on U.S. Aviation and<br />

High-speed Rail<br />

Regina Clewlow, PhD Candidate, Massachusetts Institute of<br />

Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139,<br />

United States of America, rclewlow@alum.mit.edu,<br />

Joseph Sussman<br />

In this study, we examine the energy and CO2 emission impacts of aviation and<br />

potential high-speed rail in major short-haul intercity corridors in the United<br />

States. We couple a simulation model of high-speed rail and aviation demand<br />

with a general equilibrium model that examines the impact of climate policy on<br />

the U.S. on a regional scale. We will present the modeling methodology, as well as<br />

the results of economic and emissions analyses for several policy scenarios.<br />

2 - Long-term, System-wide Impact Analysis of High-speed Rail in<br />

the Midwest Corridor<br />

Jeffrey Peters, Purdue University-Nextrans, 3000 Kent Ave.,<br />

West Lafayette, IN, 47906, United States of America,<br />

peters83@purdue.edu, En-Pei Han, Daniel DeLaurentis,<br />

Srinivas Peeta<br />

This study describes a methodology for forecasting system-wide ridership and the<br />

corresponding user and community impacts of a high-speed rail mode under the<br />

existing transportation infrastructure. Experiments with various social, economic,<br />

technological, and political trends over the next few decades are conducted using<br />

the proposed Chicago-Hub network to analyze the potential viability in the longterm.<br />

Both the methodology and the impacts of the proposed system will be<br />

discussed.


3 - HSR: Paying Our Way Forward<br />

Nicolas Norboge, Assistant Transportation Researcher, Texas<br />

Transportation Institute, 3135 TAMU, Room 334, College Station,<br />

TX, 77840, United States of America, n-norboge@ttimail.tamu.edu<br />

With renewed interest in intercity passenger rail brings the emergence of fresh<br />

efforts to develop comprehensive system plans. However, many plans fail to<br />

explain clearly how such capital-intensive projects will be paid for. This research<br />

provides a list of viable funding and financing strategies transportation<br />

professionals and policymakers to consider for paying for new HSR networks.<br />

■ SD61<br />

61- Russell- Hyatt<br />

AAS Dissertation Prize / Anna Valicek Medal<br />

Sponsor: Aviation Applications<br />

Sponsored Session<br />

Chair: Laurie Garrow, Associate Professor, Georgia Institute of<br />

Technology, School of Civil Engineering, 790 Atlantic Drive, Atlanta,<br />

GA, 30332, United States of America, laurie.garrow@ce.gatech.edu<br />

1 - Building Reliable Air-travel Infrastructure using Empirical Data<br />

and Stochastic Models<br />

Mazhar Arikan, University of Kansas, School of Business,<br />

Lawrence, KS, United States of America, mazhar@ku.edu,<br />

Milind Sohoni, Vinayak Deshpande<br />

Flight delays have been a growing issue and they have reached an all time high in<br />

recent years. We develop stochastic models, using empirical data, to analyze the<br />

propagation of delays through air-transportation networks. We then analyze<br />

robustness measures for airline networks. Our analysis enables us to make policy<br />

recommendations regarding managing bottleneck resources in the air-travel<br />

infrastructure, which if addressed, could lead to a significant improvement in airtravel<br />

reliability.<br />

2 - The Recoverable Robust Tail Assignment Problem<br />

Stephen Maher, University of New South Wales, School of<br />

Mathematics and Statistics, Sydney, 2052, Australia,<br />

stephen.maher@unsw.edu.au, Gary Froyland, Cheng-Lung Wu<br />

Disruptions affect airline operations, resulting in increased operational costs.<br />

Robust planning attempts to reduce the impact of these disruptions. We develop a<br />

less conservative robust plan using the concept of recoverable robustness for the<br />

tail assignment problem. Simultaneously solving the tail assignment planning and<br />

recovery problems to integrate recovery decisions into the original plan. Resulting<br />

in a tail assignment that is recoverable with a minimal number of operational<br />

changes.<br />

3 - Methods for Improving Robustness and Recovery in<br />

Aviation Planning<br />

Marcial Lapp, US Airways, Phoenix AZ, United States of America,<br />

mlapp@gmail.com<br />

Flight disruptions can have major effects on scheduled aircraft maintenance<br />

events. Once aircraft rotations are disrupted, plans must be updated to comply<br />

with regulations for aircraft maintenance. We address this issue by providing preand<br />

post-disruption strategies to stay compliant with regulations through our<br />

maintenance planning and recovery framework. We present results that illustrate<br />

the effectiveness of our optimization strategy and its impact on an airline’s shortterm<br />

maintenance planning process.<br />

■ SD62<br />

62- Borein A- Hyatt<br />

Combinatorial Markets<br />

Cluster: Auctions<br />

Invited Session<br />

Chair: Ben Lubin, Professor, Boston University, 595 Commonwealth<br />

Avenue, Boston, MA, 02215, United States of America, blubin@bu.edu<br />

1 - Algorithms for Finding Bayes-Nash Equilibria in<br />

Core-selecting Auctions<br />

Mark Schneider, University of Connecticut, Uconn School of<br />

Business, 81 Cheney Drive, Storrs, CT, United States of America,<br />

mschneider@business.uconn.edu, Robert Day<br />

Determining Bayes-Nash equilibria in combinatorial auctions is quite difficult, and<br />

to date, the analytical approach to finding an exact equilibrium has been<br />

successful only in very limited settings. In this work, we explore the alternative<br />

possibility of approximating equilibrium behavior using numerical methods, with<br />

a focus on the class of core-selecting auctions.<br />

INFORMS Phoenix – 2012<br />

153<br />

2 - New Payment Rules in Core-selecting Auctions<br />

Marissa Beck, Stanford University, 579 Serra Mall, Stanford, CA,<br />

94305, United States of America, mrbeck@stanford.edu,<br />

Robert Day<br />

The set of core-selecting auctions is large and previous literature has focused<br />

mostly on minimum-revenue core-selecting auctions. We explore alternative<br />

“core” pricing rules based on linear item prices and LP duality, but enforcing<br />

stricter competitive equilibrium properties. A primal-dual cutting-planes approach<br />

is used to strike a balance between the (sometimes infeasible) concept of item<br />

prices and the (always obtainable but less intuitive) concept of personalized<br />

package prices in the core.<br />

3 - Coordination in Combinatorial Auctions with Unknown Bundles<br />

Zhen Hao, Technical University Munich, Boltzmannstr 3,<br />

Garching, Germany, hao@in.tum.de, Martin Bichler<br />

One of the main strategic challenges in combinatorial auctions is the coordination<br />

problem of bidders when they do not know the bundles, which are of interest to<br />

other bidders. We propose a combinatorial auction format, in which we leverage<br />

information on losing coalitions, which is collected by the auctioneer. We analyze<br />

how bidders respond to different levels of information feedback and overall<br />

efficiency compared to the combinatorial clock auction.<br />

4 - Payment Rules through Discriminant-based Classifers<br />

Ben Lubin, Professor, Boston University, 595 Commonwealth<br />

Avenue, Boston, MA, 02215, United States of America,<br />

blubin@bu.edu, Felix Fischer, Pichayut Jirapinyo, John Lai,<br />

Paul Deutting, David Parkes<br />

In mechanism design one typically seeks socially optimal mechanisms constrained<br />

by incentive compatibility. By replacing this constraint with the goal of<br />

minimizing expected ex post regret, we are able to adapt statistical machine<br />

learning techniques to the design of payment rules in settings with multidimensional<br />

types. Specifically, we train a support vector machine with a special<br />

discriminant function, such that it implicitly establishes a payment rule with<br />

desirable properties.<br />

■ SD63<br />

SD63<br />

63- Borein B- Hyatt<br />

Joint Session Behavioral Oper./ MSOM: Empirical<br />

Studies of Behavioral Factors<br />

Sponsor: Behavioral Operations & Manufacturing & Service Oper<br />

Mgmt<br />

Sponsored Session<br />

Chair: Bradley Staats, Assistant Professor, University of North Carolina-<br />

Chapel Hill, McColl Building, CB 3490, Chapel Hill, NC, 27599,<br />

United States of America, Bradley_Staats@kenan-flagler.unc.edu<br />

1 - Learning from My Success and from Others’ Failure<br />

Bradley Staats, Assistant Professor, University of North Carolina-<br />

Chapel Hill, McColl Building, CB 3490, Chapel Hill, NC, 27599,<br />

United States of America, Bradley_Staats@kenan-flagler.unc.edu,<br />

Diwas KC, Francesca Gino<br />

Drawing on attribution theory, we investigate how individuals learn from failure<br />

and success. We use 10 years of data from 71 surgeons using a new cardiac<br />

surgery technology. We find that individuals learn more from their own successes<br />

than from their own failures, while they learn more from the failures of others<br />

than they do from others’ successes. We also find that individuals’ prior successes<br />

and others’ failures help individuals overcome their inability to learn from their<br />

own failures.<br />

2 - A Hard Take on a Soft Asset? A Test of an Operational Approach<br />

to Human Resource Management<br />

Serguei Netessine, Professor, INSEAD, Boulevard de Constance,<br />

Fountainbleau, 77305, France, Serguei.Netessine@insead.edu,<br />

Valery Yakubovich<br />

We analyze empirically agent behavior at a virtual call center in which work is<br />

allocated according to performance-based hierarchy. We use a controlled<br />

experiment to disentangle the effect of this system on agent performance.<br />

3 - Waiting Patiently: Abandonment from Emergency<br />

Department Queues<br />

Robert Batt, The Wharton School, University of Pennsylvania,<br />

3730 Walnut St., Huntsman Hall, Suite 500, Philadelphia, PA,<br />

19104, United States of America, batt@wharton.upenn.edu,<br />

Marcelo Olivares, Christian Terwiesch<br />

We present an empirical study of patient abandonment behavior from a hospital<br />

emergency department queue. We show that patients respond differently to<br />

queue length and expected wait time despite the fact that these two measures are<br />

proportional to each other. We also consider the impact of providing wait time<br />

estimates to patients and under what conditions this can lead to reduced social<br />

welfare.


SD66<br />

4 - Innovation and Learning in the Use of Components<br />

Kamalini Ramdas, Professor, London Business School, Regent’s<br />

Park, London, NW1 4SA, United Kingdom, kramdas@london.edu,<br />

Khaled Saleh, Steven Stern, Haiyan Liu<br />

We examine learning in the context of hip replacement surgery using a dataset<br />

from a major US hospital. We find that the learning associated with individual<br />

surgeons’ experience is driven by their experience at the micro level of specific<br />

device variants, with implications for how surgery is managed and taught, and for<br />

innovation in medical devices.<br />

■ SD66<br />

66- Ellis West- Hyatt<br />

Mining Time Series Data<br />

Sponsor: Data Mining<br />

Sponsored Session<br />

Chair: Onur Seref, Assistant Professor, Virginia Tech, 1007 Pamplin<br />

Hall, Blacksburg, VA, 24061, United States of America, seref@vt.edu<br />

1 - Causal Inference for Time-series Analysis: Simultaneous<br />

Denoising and Feature Selection<br />

Mohammad H. Poursaeidi, University of Houston, E 209<br />

Engineering Building, Houston, TX, United States of America,<br />

mhpoursaeidi@uh.edu, Erhun Kundakcioglu<br />

We present a new hyperplane based approach that performs regression and<br />

feature selection while simultaneously removing noise from time-series data.<br />

Mixed integer nonlinear programming formulations are developed for linear<br />

regression. These formulations are also extended via kernel trick to perform<br />

nonlinear regression. The problem is proven to be NP-hard and a heuristic<br />

algorithm is developed for large data sets.<br />

2 - Supervised Time Series Pattern Discovery through<br />

Local Importance<br />

Mustafa Baydogan, Graduate Research Assistant, Arizona State<br />

University, 699 S. Mill Avenue, Tempe, AZ, 85281, United States of<br />

America, mbaydoga@asu.edu, George Runger, Eugene Tuv<br />

In time series classification, nearest neighbor (NN) classifiers lack the aspect of<br />

interpretability since they are based on the similarity of the whole time series<br />

although temporal relations within the time series are important. We present an<br />

exploratory approach that finds the regions of the time series that have<br />

potentially representative patterns used for classification based on a local<br />

importance measure. Our algorithm provides comparable and interpretable<br />

results than competitive methods.<br />

3 - Online Piecewise Linear Segmentation and Temporal Pattern<br />

Extraction of Time Series Data<br />

Art Chaovalitwongse, University of Washington,<br />

3900 Stevens Way, Seattle, WA, United States of America,<br />

artchao@u.washington.edu, Shouyi Wang<br />

Piecewise linear segmentation (PLS) is popular to monitor and summarize time<br />

series patterns online. This talk presents a robust and efficient online<br />

segmentation algorithm that can be easily applied to various time series using a<br />

data-driven decomposition strategy and a closed-form online updating formula. A<br />

set of skeleton-point-based features are proposed to characterize time series<br />

temporal patterns. Two real-world applications demonstrate the effectiveness of<br />

the proposed approaches.<br />

4 - Information-theoretic Feature Selection with Discrete<br />

k-Median Clustering<br />

Onur Seref, Assistant Professor, Virginia Tech, 1007 Pamplin Hall,<br />

Blacksburg, VA, 24061, United States of America, seref@vt.edu,<br />

Elan Borenstein, Art Chaovalitwongse, Ya-Ju Fan<br />

We propose a novel information-theoretic feature selection method using discrete<br />

k-median (DKM) clustering, where the center for each cluster is represented as a<br />

set of samples. Normalized mutual information (NMI) scores between the output<br />

of DKM and the clusters formed by the projection of center samples are used for<br />

feature selection. Average of NMI scores are used for determining the number of<br />

clusters. We present results on simluated data and real-life neural time series data.<br />

INFORMS Phoenix – 2012<br />

154<br />

■ SD67<br />

67- Ellis East- Hyatt<br />

Joint Session QSR/ENRE: Variability and Uncertainty<br />

in Renewable Power Systems<br />

Sponsor: Quality, Statistics and Reliability & Energy, Natural Res &<br />

the Environment/Forestry<br />

Sponsored Session<br />

Chair: Eunshin Byon, Assistant Professor, University of Michigan,<br />

1205 Beal Ave., Ann Arbor, MI, 48109-2117, United States of America,<br />

ebyon@umich.edu<br />

1 - On-site Renewable Generation: Portfolio Selection and<br />

Contracts under Uncertainty<br />

Diego Klabjan, Associate Professor, Northwestern University,<br />

2145 Sheridan Road, IEMS, Evanston, IL, 60208, United States of<br />

America, d-klabjan@northwestern.edu, Sangho Shim, Jorge<br />

Arinez, Stephan Biller<br />

Investment decisions about on-site renewable generation for industrial sites are<br />

driven by net present value which inhibits many uncertainties. We present an<br />

optimization model for portfolio selection and an options contract. The<br />

uncertainties are driven by prices of renewable energy credits, on-site usage and<br />

output of sources, and future grid rates.<br />

2 - Grid Integration and R&D policy<br />

Erin Baker, University of Massachusetts, Amherst, MA,<br />

United States of America, edbaker@ecs.umass.edu,<br />

Noubara Djimadoumbaye<br />

In previous work we have analyzed the optimal energy technology R&D portfolio<br />

in the face of climate change, considering solar PV, CCS, and nuclear. Here we<br />

consider how the results are impacted by two very different assumptions<br />

regarding the integration of solar PV onto the grid. We apply a mutli-model,<br />

decision making under uncertainty framework.<br />

3 - A GIS, Optimization and Simulation Framework for Optimal PV<br />

Size and Location in Campus Environments<br />

Amirreza M. Khaleghi, The University of Arizona, 1127 E. James<br />

E. Rogers Way P.O. Box 21, Tucson, AZ, 85721-0020, United States<br />

of America, amirreza@email.arizona.edu, Ye Zhang, Ferenc<br />

Szidarovszky, Guzin Bayraksan, Young-Jun Son, Sadik Kucuksari,<br />

Maryam Hamidi<br />

A framework integrating GIS, optimization, and simulation modules is proposed<br />

to obtain the optimal placement and size for photovoltaic (PV) panels in a campus<br />

area. The GIS module finds the suitable rooftops and their panel capacity. The<br />

optimization module is then used to maximize the long term profit of PV<br />

installations. Voltage profile of the electricity distribution network is investigated<br />

in the simulation module. The proposed framework has been successfully<br />

demonstrated for a real case.<br />

4 - Assessing Extreme Loads on Wind Turbines by using<br />

Aerodynamic Simulation<br />

Eunshin Byon, Assistant Professor, University of Michigan, 1205<br />

Beal Ave., Ann Arbor, MI, 48109-2117, United States of America,<br />

ebyon@umich.edu, Youngjun Choe<br />

We develop a new methodology to predict an extreme load on a wind turbine by<br />

employing high-fidelity simulation. Due to a small probability of extreme events,<br />

crude Monte Carlo simulation requires extensive runs, which is computationally<br />

prohibitive. We devise an efficient sampling method to guide the simulation to<br />

generate the extreme events more frequently with minimal efforts. The proposed<br />

method is applied to an aerodynamic simulation.


■ SD68<br />

68- Suite 312- Hyatt<br />

Finance: Financial Engineering<br />

Contributed Session<br />

Chair: Xiangwei Wan, Assistant Professor, Shanghai Jiao Tong<br />

University, 535 Hua Fa Zhen Road, Shanghai, China,<br />

xwwan@sjtu.edu.cn<br />

1 - A Neuro-wavelet Method for the Forecasting of Financial<br />

Time Series<br />

Luis Ortega, PhD Candidate, Financial Engineering, Stevens<br />

Institute of Technology, Castle Point on Hudson, Hoboken, NJ,<br />

07030, United States of America, lortega@stevens.edu<br />

We propose a wavelet neural network model (neuro-wavelet) for the short-term<br />

forecast of stock returns from high-frequency financial data. The proposed hybrid<br />

model combines the inherent capability of wavelets and artificial neural networks<br />

to capture nonstationary and nonlinear attributes embedded in financial time<br />

series. Reasonable forecasting accuracy for one, three and five step-ahead<br />

horizons was achieved by the proposed Jordan neuro-wavelet model when<br />

compared against five other models.<br />

2 - Analysis of Non-linear Behavior - A Sensitivity-based Approach<br />

Xiangwei Wan, Assistant Professor, Shanghai Jiao Tong University,<br />

535 Hua Fa Zhen Road, Shanghai, China, xwwan@sjtu.edu.cn<br />

The standard dynamic programming fails to work in behavioral analysis due to<br />

the distortion in performance probability. In this paper, we apply a sensitivitybased<br />

approach to solve the portfolio management problem in an environment<br />

with probability distortion and obtain a closed-form optimal policy. We expect<br />

that this approach is generally applicable to optimization in other non-linear<br />

behavioral analysis.<br />

3 - Game Russian Option with the Finite Maturity<br />

Atsuo Suzuki, Meijo University, Nijigaoka 4-3-3, Kani, Japan,<br />

atsuo@urban.meijo-u.ac.jp, Katsushige Sawaki<br />

We consider Game Russian options with the finite maturity. Game Russian option<br />

is a contract that the seller and the buyer have the rights to cancel and to exercise<br />

it at any time, respectively. We discuss the pricing model of Game Russian options<br />

when the stock pays dividends continuously. We show that the pricing model can<br />

be formulated as a coupled optimal stopping problem which is analyzed as<br />

Dynkin game.<br />

4 - Estimation of Stochastic Volatility Models for Commodities with<br />

Few Options<br />

Gonzalo Cortazar, Pontificia Universidad Catolica de Chile,<br />

Vicuna Mackenna 4860, Santiago, Chile, gcortaza@ing.puc.cl,<br />

Federico Alonso<br />

Stochastic volatility models are required for commodity prices. To obtain good<br />

parameter estimates, prices for non-linear derivatives with different maturities are<br />

necessary, but some commodities trade only futures and short-term options. We<br />

propose a three-factor multicommodity model with stochastic volatility and show<br />

how to use long-term options written on one commodity to help estimate the<br />

dynamics of another. The model is implemented for Brent and WTI commodities<br />

with excellent results.<br />

■ SD69<br />

69- Suite 314- Hyatt<br />

Optimization and Financial Engineering<br />

Cluster: Optimization in Finance<br />

Invited Session<br />

Chair: Martin Haugh, Columbia, martin.b.haugh@gmail.com<br />

1 - Hope, Fear and Aspirations<br />

Xuedong He, Assistant Professor, Columbia University, 316 S. W.<br />

Mudd Building, 500 W. 120th Street, New York, NY, 10027, United<br />

States of America, xh2140@columbia.edu<br />

We propose a rank-dependent portfolio choice model in continuous time that<br />

captures the role in decision making of three emotions: hope, fear and<br />

aspirations. We solve the portfolio choice problem both thoroughly and<br />

analytically, and these solutions motivate us to introduce a fear index, a hope<br />

index and a lottery-likeness index to quantify the impacts of three emotions,<br />

respectively, on investment behavior.<br />

INFORMS Phoenix – 2012<br />

155<br />

2 - Approximate Methods for Dynamic Portfolio Choice with<br />

Learning<br />

Poomyos Wimonkittiwat, University of California-Berkeley,<br />

Berkeley, CA, United States of America, poomyos@berkeley.edu,<br />

Andrew Lim<br />

We develop approximate methods for dynamic portfolio choice problems with<br />

hidden states, where the transition probabilities may also need to be learned. We<br />

derive semi-explicit expressions for the optimal policy which can be implemented<br />

using tools from MCMC.<br />

3 - Martingale Dual Methods for Zero-Sum Games<br />

Chun Wang, Columbia University, 500 West 120th Street,<br />

Mudd 323, New York, NY, 10027, United States of America,<br />

cw2519@columbia.edu, Martin Haugh<br />

Martingale duality based on information relaxations has recently been developed<br />

for zero-sum optimal stopping games. In this talk, we consider generalizing this<br />

duality for more general zero-sum dynamic games.<br />

4 - Portfolio Selection with Multiple Spectral Risk Constraints<br />

Carlos Abad, Columbia University IEOR, 500 W 120th St., New<br />

York, NY, 10027, United States of America, ca2446@columbia.edu,<br />

Garud Iyengar<br />

We propose an iterative algorithm to efficiently solve the portfolio selection<br />

problem with multiple spectral risk constraints (CVaR is a special case of the<br />

spectral risk function). In each step, the algorithm solves a very simple separable<br />

convex quadratic program. We report numerical results that show that our<br />

proposed algorithm is very efficient, and is at least two orders of magnitude faster<br />

than the state of the art general purpose solver for all practical instances.<br />

■ SD70<br />

SD70<br />

70- Suite 316- Hyatt<br />

Social Media and Social Broadcasting Network<br />

Sponsor: Information Systems<br />

Sponsored Session<br />

Chair: Huaxia Rui, University of Texas at Austin, Austin, TX,<br />

United States of America, huaxia@utexas.edu<br />

1 - Modeling Multicategory Online Video Demand in Social Media<br />

Qian Tang, University of Texas at Austin, Austin, TX, 78703,<br />

United States of America, qian.tang@phd.mccombs.utexas.com,<br />

Liangfei Qiu, Andrew Whinston<br />

The popularity of social media has greatly increased the demand for online<br />

videos. The demand for online videos may be influencd by online WOM, social<br />

influence, the provider’s reputation, and competition. Our paper disentangles the<br />

influence of these factors. We model a viewer’s decision as first choosing<br />

categories and then videos within the categories. The hierarchical model allows<br />

videos within a category to have correlated demand.<br />

2 - The Value of Being Social: How Bloggers Attract Followers<br />

Hailiang Chen, City University of Hong Kong, Department of<br />

Information Systems, Hong Kong, Hong Kong-PRC,<br />

chenhl.2007@gmail.com, Yu Hu, Prabuddha De<br />

In a blog community, for a blogger to build readership and gain popularity,<br />

ultimately, the key should be to write good quality content. However, from a<br />

marketing perspective, how much additional value does being social with her<br />

readers bring about to the blogger? This study intends to quantify the value of<br />

being social in the blogging context and to examine how bloggers should manage<br />

their conversations with readers.<br />

3 - Information Exchange in Prediction Markets: How Social<br />

Networks Promote Forecast Efficiency<br />

Liangfei Qiu, University of Texas at Austin, 2225 Speedway,<br />

Austin, TX, 78712, United States of America,<br />

qiuliangfei@gmail.com, Andrew Whinston, Huaxia Rui<br />

This paper studies the effects of information exchange and social networks on the<br />

performance of prediction markets. We provide a game-theoretic framework to<br />

resolve the question: Can social networks and information exchange promote the<br />

forecast efficiency in prediction markets? Our study shows that social network is<br />

not a panacea in terms of improving forecast efficiency. The abuse of social<br />

networks could be detrimental to forecast performance.


SD71<br />

■ SD71<br />

71- Suite 318- Hyatt<br />

Management and Economics of IS<br />

Sponsor: eBusiness<br />

Sponsored Session<br />

Chair: Dennis Kundisch, Professor, University of Paderborn,<br />

Warburgerstrasse 100, Paderborn, Germany,<br />

dennis.kundisch@wiwi.uni-paderborn.de<br />

1 - IT Investments and the Structure of Production<br />

Fengmei Gong, University of Calgary, Haskayne School of<br />

Business, Calgary, Canada, fgong@ucalgary.ca, Barrie Nault<br />

We examine the potential for determining how investments in information<br />

technology (IT) from an industry and its value chain partners affects the inputoutput<br />

structure of production.<br />

2 - Valuation of Interdependent IT Projects – A Real Option<br />

Approach Considering Unhedgeable Risks<br />

Steffen Zimmermann, Assistant Professor, University of Innsbruck,<br />

Universitaetsstr. 15, Innsbruck, 6020, Austria,<br />

Steffen.Zimmermann@uibk.ac.at, Marcel Mueller, Sebastian Stöckl<br />

To value interdependent IT projects, financial option pricing models like the<br />

Black-Scholes model (BSM) are frequently suggested. However, one major<br />

concern about applying these models for real options, is the assumption that all<br />

risks need to be hedged by a replicating portfolio. Thus, we present an<br />

enhancement of the BSM where we consider hedgeable and unhedgeable risks by<br />

two seperate stochastic processes. In doing so, we find out that the BSM<br />

undervalues real options systematically.<br />

3 - Risk-aware SLA Design for Enterprise Information Systems<br />

Dirk Neumann, Professor, Albert-Ludwigs Universitat Freiburg,<br />

Platz der Alten Synagoge 1, Freiburg, 79085, Germany,<br />

dirk.neumann@is.uni-freiburg.de, Markus Hedwig,<br />

Simon Malkowski<br />

Since effective IT systems are necessary for business practices, growing operation<br />

costs necessitate the search for efficient delivery models. Cloud Computing<br />

provides a powerful alternative to traditional IT operation. Firms still have<br />

reservations about migrating to the Cloud due to the lack of binding SLA<br />

offerings. Service providers hesitate to offer binding SLAs as assessing economic<br />

risks is challenging. We present a model for SLA design for clouds to estimate the<br />

induced operational risk.<br />

4 - Does It Pay Off to Bid Aggressively? An Empirical Study<br />

Philipp Herrmann, University of Paderborn, Warburger Strafle 100,<br />

Paderborn, Germany, Philipp.Herrmann@wiwi.uni-paderborn.de,<br />

Mohammad Rahman, Dennis Kundisch<br />

We empirically investigate the payoff of aggressive bidding in an electronic<br />

auction. We use a unique and very rich dataset containing actual market<br />

transaction data for approximately 7,000 pay-per-bid auctions. Our research<br />

design allows us to separate the effect of an aggressive bidding strategy to signal<br />

one’s own valuation from the effect of bidding aggressively due to impatience. We<br />

find a strong and significantly negative effect of aggressive bidding on the<br />

likelihood to win an auction.<br />

■ SD72<br />

72- Suite 322- Hyatt<br />

Advances in Optimization Modeling Languages and<br />

Systems I<br />

Cluster: ICS-Advances in Optimization Modeling Languages and<br />

Systems<br />

Invited Session<br />

Chair: Robert Fourer, President, AMPL Optimization, Inc, 2145<br />

Sheridan Road, Evanston, IL, United States of America, 4er@ampl.com<br />

1 - A Generic Benders Decomposition Algorithm for the AIMMS<br />

Modeling Language<br />

Marcel Hunting, Paragon Decision Technology, Schipholweg 1,<br />

Haarlem, 2034 LS, Netherlands, Marcel.Hunting@aimms.com<br />

We present an implementation of Benders Decomposition, in the AIMMS<br />

modeling language, that is easy to use on a broad class of problems. The user only<br />

needs to specify which variables belong to the master problem and which to the<br />

subproblems. Benders’ cuts are generated automatically. Several cut selection<br />

criteria are available. The Benders Decomposition algorithm is implemented as a<br />

white box algorithm.<br />

INFORMS Phoenix – 2012<br />

156<br />

2 - Automated Conversion of Common Optimization Problem<br />

Structures to Mixed-integer Linear Programs<br />

Jared Erickson, Northwestern University, 2145 Sheridan Road,<br />

Room C210, Evanston, IL, 60208, United States of America,<br />

JaredErickson2012@u.northwestern.edu, Robert Fourer<br />

Optimization problems conveniently represented through the use of disjunctive<br />

linear constraints or polynomials in binary variables are commonly recast as<br />

MILPs for solution. We present algorithms that detect these types of problems and<br />

transform them to MILPs automatically. Our implementation uses the AMPL<br />

modeling language and works with various solvers. The transformations allow for<br />

a wider variety of solvers to be used and can lead to reductions in solution time.<br />

3 - ZIMPL 3.3: An Open Source Modelling Language<br />

Gerald Gamrath, Research Assistant, Zuse-Institut Berlin, Takustr<br />

7, Berlin, 14199, Germany, gamrath@zib.de, Thorsten Koch<br />

ZIMPL is a freely available open source algebraic modelling language for<br />

describing linear and non-linear mixed integer programs. It is very portable and<br />

can be used either standalone, embedded into an application, or linked to a<br />

solver. One feature of ZIMPL is the use of rational arithmetic for all computations.<br />

We will give an overview of the latest release and in particular to the SCIP<br />

integration, which interfaces with the exact solver version of SCIP and also with<br />

the MINLP solver.<br />

4 - APMonitor Modeling Langauge for Mixed-integer Differential<br />

Algebraic Systems<br />

John Hedengren, Assistant Professor, Brigham Young University,<br />

350 CB, Provo, UT, 84602, United States of America,<br />

john_hedengren@byu.edu<br />

The APMonitor Modeling Language (APM) is an optimization platform for<br />

differential and algebraic equations (DAEs) and is coupled with large-scale solvers<br />

for data reconciliation, dynamic optimization, and nonlinear predictive control.<br />

Applications include computational biology, unmanned aerial systems, chemical<br />

process control, smart grid optimization, and oil and gas upstream monitoring<br />

systems.<br />

■ SD73<br />

73- Suite 324- Hyatt<br />

Stochastic Optimization in Finance<br />

Cluster: Quantitative Finance<br />

Invited Session<br />

Chair: Tim Siu-Tang Leung, Columbia University, New York, NY,<br />

United States of America, leung@ieor.columbia.edu<br />

1 - Utility Maximization in Hidden Regime Switching Markets<br />

Agostino Capponi, Assistant Professor, Purdue University,<br />

315 North Grant Street, West Lafayette, IN, 47906,<br />

United States of America, capponi@purdue.edu<br />

We consider a regime switching market, where investors can trade a stock, a riskfree<br />

bond, and a defaultable bond, whose price is only observed with noise. The<br />

dynamics of the instruments are driven by hidden Markov chains. We provide the<br />

HJB equations for the partially observed stochastic control problem, and<br />

demonstrate how to solve them numerically. We then illustrate the dependence<br />

of the strategies on the level of noise in market, risk aversion of the investor, and<br />

default risk.<br />

2 - Portfolio Optimization under Convex Incentive Schemes<br />

Maxim Bichuch, Princeton University, Dept. of Operations<br />

Research and Finance, Sherrerd Hall, Charlton Street, Princeton,<br />

NJ, 08544, United States of America, mbichuch@princeton.edu,<br />

Stephan Sturm<br />

We consider a utility maximization problem of terminal wealth from the point of<br />

view of a portfolio manager paid by convex incentives. Even though the<br />

manager’s utility function is concave, the result is a non-concave optimization<br />

problem that does not fit into the classical portfolio optimization theory. Using<br />

duality theory, we prove existence and uniqueness of the optimal wealth in<br />

general (incomplete) markets.<br />

3 - Optimal Incentives for Delegated Portfolio Selection<br />

Stephan Sturm, Worcester Polytechnic Institute, c/o Princeton<br />

University, 116, Sherrerd Hall, Princeton, NJ, 08544,<br />

United States of America, ssturm@princeton.edu, Maxim Bichuch<br />

We study the problem of an investor who lets a fund manager manage his wealth.<br />

The latter is paid by an incentive scheme based on the performance of the fund.<br />

Manager and investor have different risk aversions; the manager may invest in a<br />

financial market to form a portfolio optimal for his expected utility whereas the<br />

investor is free to choose the incentives – taking only into account that the<br />

manager is paid enough to accept the managing contract.


4 - Private Valuation of Claims using Stochastic Programming<br />

Alan King, IBM Research, 1101 Kitchawan Road, Yorktown<br />

Heights, NY, 10598, United States of America, kingaj@us.ibm.com,<br />

Olga Streltchenko<br />

Valuing contingent claims can be formulated as a stochastic programming<br />

problem. We explore the advantages of the SP model in modeling realistic aspects<br />

of investing, including: calibration constraints, existing positions, spreads, and risk<br />

preferences. Capturing these realistic features of investing and hedging leads to a<br />

paradigm in which investors can construct and calibrate a private valuation<br />

measure for the evaluation of trades and the pricing of illiquid positions.<br />

Monday, 8:00am - 9:30am<br />

■ MA01<br />

01- West 101- CC<br />

Recent Advances in Nonlinear Optimization<br />

Sponsor: Optimization/Global Optimization<br />

Sponsored Session<br />

Chair: Evrim Dalkiran, Assistant Professor, Wayne State University,<br />

4815 4th St Manufacturing Eng., Detroit, Mi, 48202,<br />

United States of America, evrimd@wayne.edu<br />

1 - Disjunctive Cutting Planes for Linear<br />

Complementarity Constraints<br />

Trang Nguyen, University of Florida, 303 Weil Hall, Gainesville, FL,<br />

32611, United States of America, trang@ufl.edu,<br />

Jean-Philippe Richard, Mohit Tawarmalani<br />

We discuss the problem of generating strong cutting planes for linear programs<br />

with linear complementarity constraints (LPCCs). In particular, we exploit<br />

complementarity constraints to derive cuts from the optimal simplex tableaux of<br />

the LP relaxation of the problem. We also introduce the notions of split cut and<br />

split closure for LPCC problems with bounded variables. We compare these<br />

notions with their integer programming counterpart and present preliminary<br />

numerical results.<br />

2 - Complexity of Deciding Convexity<br />

Amir Ali Ahmadi, Postdoctoral Associate, Massachusetts Institute<br />

of Technology, 195 Binney St., Cambridge, MA, 02142,<br />

United States of America, a_a_a@mit.edu<br />

We show that deciding convexity of polynomials of degree as low as four is<br />

strongly NP-hard. This solves a problem that appeared as one of seven open<br />

problems in complexity theory for numerical optimization in 1992. Joint work<br />

with A. Olshevsky, P.A. Parrilo, and J.N. Tsitsiklis.<br />

3 - An Algorithm for the Projection a Point on the Intersection of<br />

Two Nonnegative Hyperplanes and the Nonnegative Orthant<br />

Claudio Santiago, Postdoc Researcher, Lawrence Livermore<br />

National Laboratory, 7000 East Ave., Livermore, CA, 94550,<br />

United States of America, pratas@gmail.com, Nelson Maculan,<br />

Maria Helena Jardim<br />

In this work, we present a quadratic algorithm for the projection of a point on the<br />

intersection of two hyperplanes with nonnegative coefficients and the<br />

nonnegative orthant. Interior point methods are the most efficient algorithm in<br />

the literature to solve this problem. While efficient in practice, their efficiency is<br />

highly dependent on a series of parameters (especially for nonlinear problems).<br />

We propose a new method based on the KKT optimality conditions.<br />

■ MA02<br />

02- West 102 A- CC<br />

Issues and Advances in Real Options<br />

Sponsor: Decision Analysis<br />

Sponsored Session<br />

Chair: Reidar Bratvold, Professor, University of Stavanger,<br />

Department of Petroleum Engineering, Stavanger, 4036, Norway,<br />

reidar.bratvold@uis.no<br />

Chair: Joe HahnAssociate Professor, Pepperdine University,<br />

Malibu Campus, Malibu, CA, United States of America,<br />

Joe.Hahn@pepperdine.edu<br />

1 - Recent Developments in Valuation to Support Real Asset<br />

Decision-Making: A CO2 Storage Example<br />

David Laughton, Principal/Adjunct Professor, David Laughton<br />

Consulting Ltd./University of Alberta School of Business,<br />

INFORMS Phoenix – 2012<br />

157<br />

11006-125 St., Edmonton, AB, T5M 0M1, Canada,<br />

laughton.david@davidlaughtonconsulting.ca<br />

Value is an important metric in many large public corporations shaping the<br />

process of designing and choosing real assets. Separating and adopting the two<br />

aspects of so-called “real options” valuation (derivative asset valuation and<br />

decision tree analysis) can produce a technically superior form of valuation that<br />

conforms with the organisational structures and work flows in these corporations.<br />

This increases the net benefit of adopting the proposed changes and makes it less<br />

costly to do so.<br />

2 - A Decision Analysis Approach to Valuing Real Options<br />

Ross Shachter, Associate Professor, Stanford University,<br />

Department of Management Science and Eng, Huang Engineering<br />

Center, Stanford, CA, 94305, United States of America,<br />

shachter@stanford.edu, Stephen Derby<br />

We extend the standard finite-state multiple-period model of investment in a real<br />

option by including return to scale (RTS), the derivative of the buying price with<br />

respect to the scale of investment. RTS is either constant or decreasing, depending<br />

on whether all of the investment risk can be hedged, as assumed in financial<br />

option pricing theory. RTS increases with wealth and trading frequency. We<br />

provide bounds and approximations for the investment value without imposing<br />

constant RTS.<br />

3 - Risk-Sensitive Real Options Decisions<br />

H. Dharma Kwon, University of Illinois at Urbana-Champaign,<br />

1206 South Sixth Street, Champaign, IL, 61820,<br />

United States of America, dhkwon@illinois.edu, Michael Lim<br />

We consider a class of stopping problems under uncertainty with non-linear<br />

utility functions. We focus on stationary stopping problems and consider<br />

stationary stopping policies. We formulate credible stationary stopping policies,<br />

from which the decision-maker will have no incentive to deviate.<br />

4 - The Choice of Stochastic Process in Real Option Valuation<br />

Luiz Ozorio, Professor, IBMEC Business School, Av. Afranio de<br />

Melo Franco 149/403, Rio de Janeiro, RJ, 22430-060, Brazil,<br />

lmozorio@ibmecrj.br, Luiz Eduardo Brandao, Adrian Pizzinga,<br />

Carlos Bastian-Pinto<br />

A main issue in valuation modeling is the choice of the stochastic process that<br />

describes the asset price performance. Particularly, in investment projects that<br />

show a high level of managerial flexibility in conditions of uncertainty the<br />

assumption of a specific process can have an impact on the project value and the<br />

investment rule. This work discusses the choice of stochastic process in real<br />

options valuation and useful tests and theoretical considerations to give support<br />

to this task.<br />

■ MA03<br />

MA03<br />

03- West 102 B- CC<br />

Joint Session: DAS/Emergency Mgmt: Security and<br />

Behavioral Game Theory<br />

Sponsor: Decision Analysis & Applications in Emergency<br />

Management and Terrorism Security<br />

Sponsored Session<br />

Chair: Richard John, Associate Professor of Psychology, University of<br />

Southern California, Los Angeles, CA, United States of America,<br />

richardj@usc.edu<br />

Co-Chair: Heather Rosoff, University of Southern California,<br />

Los Angeles, CA, United States of America, rosoff@usc.edu<br />

1 - Security Games: Challenges in Modeling Human<br />

Adversarial Behavior<br />

Milind Tambe, University of Southern California, Los Angeles, CA,<br />

United States of America, tambe@usc.edu, Rong Yang, James Pita<br />

Stackelberg security games have received significant attentions in recent years<br />

given their deployment for real-world security problems. Many of these realworld<br />

systems have adopted the standard game-theoretic assumption that the<br />

adversaries are perfectly rational; this assumption may not hold when facing<br />

human adversary with bounded rationality. We provide an overview of our<br />

research efforts to address human bounded rationality in the context of security<br />

games.

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