Informs Annual Meeting 2017

WB36

INFORMS Houston – 2017

3 - Effectiveness of Coordination Mechanisms Based on the Exchange Prices Ali Hassanzadeh Kalshani, Graduate Student, University of California-Irvine, 1723 Verona Place, Irvine, CA, 92617, United States, ahassan2@uci.edu, John G.Turner, Luyi Gui In many real-world settings where resources are shared, decentralized agents (e.g., individual competing firms) maximize their profits, and in so doing, choose to use an amount of resources. Motivated by a desire to understand the theoretical and structural underpinnings of what makes coordinating decentralized agents hard or easy, we study what is known as the Price of Anarchy, defined as the ratio of the combined profit achieved by all decentralized agents to the profit achievable by a monopolist which owns all of the resources herself. 4 - System of Systems Approach to Develop an Energy Water Nexus Model under Uncertainty Afshin Ghassemi, University of Illinois at Chicago, 1200 W. Harrison St, Chicago, IL, 60607, United States, Aghass2@uic.edu, Michael J. Scott A water-energy nexus model is an interdependent systems approach to study two infrastructure subsystems, energy and water, simultaneously. A robust, linear, mixed-integer, multi-period model is proposed to study the water-energy nexus as an integrated system. The proposed model leads to decreased total system cost and limits total system pollution (e.g., waste water pollution). Moreover, the robust model is immune to a reasonable amount of uncertainty (e.g., water demand uncertainty). The model solutions include detailed decisions for all existing sub-systems in the water-energy nexus. 5 - A Mixed- Integer Quadratic Consolidation Model for a Two-echelon Supply Chain Sepideh Alavi, PhD Candidate, University of Wisconsin Milwaukee, 3202 N Maryland Ave, Milwaukee, WI, 53202, United States, alavi@uwm.edu, Matthew Petering, Anthony Ross This paper proposes a shipment consolidation model addressing production and consolidation decisions by a manufacturer which provides inventory replenishments to multiple distribution centers (DCs). The model is not restricted to specific rules such as aggregation of shipments at regular times or consolidating when a predetermined quantity is accumulated. We develop a mixed-integer quadratic optimization model to simultaneously determine the optimal inventory replenishment and consolidation times. Numerical results, obtained via MIQP and a genetic algorithm are discussed. 6 - A Dynamic Supplier Selection and Inventory Management Model in a Serial Supply Chain with a Novel Price Break Scheme and Flexible Time Periods Lisha Duan, PhD Student, The Pennsylvania State University, University Park, PA, United States, lud149@psu.edu, José Ventura A new supplier price break scheme is introduced and incorporated into an integrated inventory planning model for a serial supply chain that minimizes the overall incurred cost including procurement, inventory holding, production, and transportation. A mixed-integer linear programming(MILP)formulation is presented addressing this multi-period, multi-supplier, and multi-stage problem with time-varying demand. Then, the length of the time period is considered as a variable. A new MILP formulation is derived. Sufficient evidence demonstrates that the length of the time period has a significant influence on supplier selection, lot sizing allocation, and inventory planning decisions. 351F Service Science Contributed Session Chair: Arpan Rijal, Erasmus University, Rotterdam, Netherlands, rijal@rsm.nl 1 - Single-machine Common Due Date Earliness/tardiness Scheduling with Machine Unavailability Kerem Bulbul, Associate Professor, Sabanci University, Faculty of Engineering & Natural Sciences, Orhanli, Tuzla, Istanbul, 34956, Turkey, bulbul@sabanciuniv.edu, Safia Kedad-Sidhoum, Halil Sen We study the problem of scheduling a single machine as to minimize the total deviation of the job completion times from an unrestrictive common due date when one or several fixed intervals of unavailability are present in the planning horizon. Several interesting cases are identified and explored, depending on the resumability scheme (resumable, non-resumable, semi-resumable) and the location of the interval of machine unavailability with respect to the common due date. The focus of analysis is on structural properties and drawing the boundary between polynomially solvable and NP-complete cases. Pseudo-polynomial DP algorithms are devised for NP-complete variants in the ordinary sense. WB36

2 - No Wait Open Shop Scheduling Problem with Sequence Dependent Setups and Release Dates Rahman Khorramfar, PhD Student at North Carolina State University, North Carolina State University, Raleigh, NC, United States, rahman.khorramfar@gmail.com This paper deals with no-wait open shop scheduling with sequence dependent setup times and release dates, minimizing total completion times. We present three formulation of the problem based on different decision variable paradigms and investigate some computational aspects of the models. For large size problems, we first propose a novel encoding and decoding scheme, and present four particle Swarm Optimization (PSO)-based algorithms and four Tabu Search (TS)-base algorithms. To evaluate the performance of the algorithms we carry out two cpmputational experiments.The evaluation of algorithms indicate that one of the TS-based algorithms slightly outperforms the others. 3 - Performance of Various Formulations for Machine Scheduling Problems with and with out Setups Ekin Koker, University of Massachusetts, Mechanical and Industrial Engineering, 160 Governors Drive, Amherst, MA, 01003, United States, ekoker@umass.edu, Ana Muriel Machine scheduling problems are one of the most widely studied problem families in operations research. Yet, due to their challenging nature, most of the literature has focused on developing heuristics, testing meta-heuristics or exploring the effectiveness of dispatching rules. Comparison of different modeling techniques in exact approaches such as mixed integer programming has received surprisingly little attention. In this paper, we computationally compare the effectiveness of formulations based on direct positional variables against relative positional variables in a variety of machine scheduling problems, including parallel machine and flow shop settings with and without setups. 4 - Minimizing Labor Costs in Picker-to-parts Warehouses with Delivery Due Time Windows Arpan Rijal, PhD Candidate, Erasmus University, Postbus 1738, Rotterdam, 3000 DR, Netherlands, rijal@rsm.nl Many picker-to-parts face temporal and spatial limitations in the staging process. To address these limitations, orders have to be brought to staging lanes within a predefined due time window before they are loaded onto trucks and shipped. We study the scheduling of order-pickers in picker-to-parts warehouses with hard pick delivery due time windows. We formulate the problem and evaluate its complexity. Additionally, we present an efficient heuristics to tackle real-sized instances. 352B Research on Service Operations Sponsored: Service Science Sponsored Session Chair: Aly Megahed, IBM Research-Almaden, San Jose, CA, 95123, United States, aly@gatech.edu Co-Chair: Vahid Nourbakhsh, University of California- Irvine, The Paul Merage School of Business, Irvine, CA, 9, United States, vahidn@uci.edu 1 - Managing Service Design in Decentralized Supply Chains Customers buying certain products may lack functional knowledge and need help after purchase. The retailer (or manufacturer) can invest in pre-sales effort to educate customers; We study the service channel design problem with different structures and show that the retailer would even be worse off in a cost-sharing contract. 2 - Optimal Practice of Bundling in a Duopoly Araz Khodabakhshian, UCLA, 501 Gayley Avenue, Apt 11, Los Angeles, CA, 90024, United States, arazkhodabakhshian@gmail.com, Uday S.Karmarkar, Guillaume Roels Service bundles are common in many industries, but there are also several examples of firms that choose not to bundle. We study bundling in the presence of competition to examine its implications for bundling strategy. We model the bundling strategy of two firms offering two products to heterogeneous customer populations as a two-stage non-cooperative game. Firms can practice mixed bundling. In the first stage, firms choose their product offering combinations. In the second, they simultaneously choose prices for their offerings. We modeled this game as a price competition and show that in equilibrium, at most one firm bundles. We also study the quantity competition dual of this game. Huaqing Wang, Emporia State University, 1 Kellogg Circle, Cremer Hall, Emporia, KS, 66801, United States, hwang4@emporia.edu, Haresh B. Gurnani, Yu Tang WB37

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