2016 INFORMS Annual Meeting Program

WC84

INFORMS Nashville – 2016

WC82 Broadway G- Omni Networks and Graphs III Contributed Session

time period, the manufacturer and the supplier decide their capacity levels and the production quantity to satisfy a random demand. Using stochastic models, we analyze optimal production and capacity investment decisions, and also analyze the inefficiencies in the decentralized system. 2 - A Joint Supplier Selection And Lot-sizing Problem With Quality Constraint Under An All-unit Discount Environment Xin Li, Pennsylvania State University, University Park, PA, 16802, United States, xzl118@psu.edu, Jose Antonio Ventura, M. Jeya Chandra This paper considers a joint supplier selection and lot-sizing problem, where suppliers are capacitated and offer all-unit discounts. The product’s perfect rate differs among suppliers and a minimum overall acceptable perfect rate exists. A cyclic order schedule is employed and the set of selected suppliers, and corresponding order quantities and frequencies are determined accordingly so that the total cost per time unit is minimized. A mixed-integer nonlinear mathematical model is presented and analyzed. A dynamic programming algorithm is proposed to solve the discretized version of the model. 3 - Liquid Helium Global Supply Chain Modeling And Optimization Ethan Malinowski, University at Buffalo, 8 Affinity Lane, Apt 251 E, Buffalo, NY, 14215, United States, ejmalino@buffalo.edu, Mark Karwan, Banu Gemici-Ozkan, Jose M Pinto The global supply chain for liquid helium presents a complex structure due to increasing foreign demand, elaborate recovery techniques, and costly forms of distribution. Although the task contains parallels to the vehicle routing and traveling salesmen problems, supply requirements and problem-specific network constraints require a unique optimization model. We develop a large-scale discrete time, path-based integer-programming model which solves optimally using CPLEX. Computational results implementing a rolling horizon structure and testing against historical data are presented. WC84 Broadway J- Omni Supply Chain, Risk III Contributed Session Chair: Irina Dolinskaya, Northwestern University, 2145 Sheridan Road, Tech Institute, M235, Evanston, IL, 60208-3119, United States, dolira@northwestern.edu 1 - A Robust Decision-Making In a Supply Chain Under Disruption Risks Tadeusz J Sawik, Professor and Chair, AGH University of Science & Technology, Al. Mickiewicza 30, Krakow, 30059, Poland, sawik@zarz.agh.edu.pl A robust decision-making in a supply chain under local and regional disruption risks is considered. The robustness refers to an equitably efficient average and worst-case performance, which reflects the decision-makers common requirement to maintain an equally good performance of a supply chain under different conditions. The problem objective is to select suppliers of parts and schedule customer orders for products to equitably optimize average and worst- case cost or service level. The robust solution is obtained using the ordered weighted averaging aggregation of the expected value and the conditional value- at-risk. 2 - Investigating WOMs Behind Crisis: Contingent Negative Spillover Effect In Supply Chain Partnership Xiaolun Wang, PhD Candidate, Fudan University, 670 Guoshun Road, Yangpu District, Shanghai, 200433, China, wangxiaolun@fudan.edu.cn, Cenying Yang, Cheng Zhang This paper aims to investigate mechanism that governs the vertical spillover effect of crisis from stricken firm to its supply chain partners. Based on Accessibility- Diagnosticity theory, we explain why and when WOM could contribute to the negative spillover, that is, guilt by association mechanism for large downstream partners and information asymmetry mechanism for small upstream partners. Based on a merged, multi-sources, and longitudinal dataset from Capital IQ, and Sina Microblog, we apply PVAR model with GMM estimators to capture the dynamic interactions between WOM attributes (volume/valence/dispersion) and abnormal return of the supply chain partners. 3 - Supplier Assessment Policies In Total Cost Auctions Karca Aral, Asst. Professor, Syracuse University, 721 University Avenue, Syracuse, NY, 13244, United States, kdaralwa@syr.edu We address the trade-off between compulsory and voluntary supplier assessments in a procurement auction. Compulsory assessments enable buyers to learn the total cost of ownership (TCO) before selecting a supplier; however, this leads to decreased supplier competition. In contrast, voluntary assessments increase supplier competition, however provide less information on the TCO.

Chair: Monica Gentili, IPAT, Georgia Institute of Technology, 75 5th Street NW, Suite 600, Atlanta, GA, 30308, United States, mgentili@unisa.it 1 - The Impact Of Visual Aesthetics On The Utility, Affordance, And Readability Of Network Graphs Patrick Michael Dudas, Faculty Research Associate, Pennsylvania State University, 691 Wiltshire Drive, State College, PA, 16803, United States, pmd19@psu.edu Network visualizations facilitate the understanding of relationships, where research classically focuses more on readability. While existing studies are mostly concerned with the readability of topological mapping (based on different layouts), this work focuses on how visual aesthetics affect users’ understanding of network structures by both readability (direct utility) and perceived affordance (indirect utility). Accompanied with these measures are eye-tracking data and retrospective think-aloud protocol to provide qualitative context to these visual strategies. Our study contributes to the understanding of visual aesthetics in network visualization design. 2 - An Algorithm To Design LDPC Codes With Low Error Floor In Communication Systems Banu Kabakulak, Bogazici University, Istanbul, Turkey, banu.kabakulak@boun.edu.tr, Z. Caner Ta kın, Ali Emre Pusane In a digital communication system, information is sent from one place to another over a noisy communication channel using binary symbols (bits). Original information is encoded by adding redundant bits, which are then used by low- density parity-check (LDPC) codes to detect and correct the errors. Error correction capability of an LDPC code is severely degraded due to harmful structures such as cycles in its bipartite graph representation (Tanner graph). Hence, we can achieve a low error floor when there are no small cycles in Tanner graph. We introduce an integer programming formulation for maximizing the smallest cycle size in Tanner graph. We propose a branch-and-cut algorithm for its solution. 3 - Critical Effect Of Dependence Clusters On Cascading Failures In Network Systems Jian Zhou, PhD Student, Rutgers University, Bevier Road, Buell Apt, 0378, 2145 Bpo Way, Piscataway, NJ, 08854, United States, zhoujian977913@gmail.com, Ning Huang, David W Coit Current failure models focusing on network load dynamics provide powerful approaches to analyze cascading failures in networks. However, previous studies don’t take the impacts of dependencies among network nodes beyond network connection into account. Recent research show that dynamics of networks considering dependencies differ greatly from that with only connectivity links. Based on a mixed cascading failure model for networks including load dynamics and dependencies, we analyze numerically the influences of dependence clusters of nodes on failure mechanism in networks subjecting to random failures. How network topology affects the robustness of such networks are also investigated. 4 - The Interval Transportation Problem Monica Gentili, Associate Professor, University of Louisville, 132 Eastern Parkway, Louisville, KY, 40205, United States, monica.gentili@louisville.edu, Raffaele Cerilli, Ciriaco D’Ambrosio The basic transportation problem (TP) deals with the transportation of goods from a set of supply points to a set of demand points so as to minimize linear transportation costs. The interval transportation problem extends TP to take into consideration uncertainty in the supply and demand when they are expressed in interval forms. We analyze the set of the optimal solutions of the problem and apply a heuristic algorithm to explore it.

WC83 Broadway H- Omni Supply Chain Optimization III Contributed Session

Chair: Ethan Malinowski, University at Buffalo, 8 Affinity Lane, Apt 251E, Buffalo, NY, 14215, United States, ejmalino@buffalo.edu 1 - Stochastic Models For Strategic Sourcing In Energy Industry Ashesh Kumar Sinha, University of Wisconsin-Madison, 1402 Regent St Apt 731A, Madison, WI, 53711, United States, ashesh.sinha24@gmail.com, Ananth Krishnamurthy We analyze the supply chain in oil and gas industries that manufacture custom- engineered equipment. We consider a multi-period centralized system and decentralized system where the product can be made either at the in-house manufacturing facility or at dedicated facilities of the external supplier. At each

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