Informs Annual Meeting Phoenix 2018

INFORMS Phoenix – 2018

TA51

2 - Analysis of a Healthcare System Consisting of Public and Private Facilities Seyedehsaloumeh Sadeghzadeh, Virginia Tech, Blacksburg, VA, 24060, United States, Lerzan E. Ormeci, Pelin Canbolat We consider a setting where a healthcare service is provided by two facilities, one public, and one private. Each facility is represented by an M/M/1 queue with different service rates and fees. Customers strategically choose one of the two facilities to minimize their expected cost, which consists of waiting costs and fees, under two different conditions corresponding to observable and unobservable queues. We also analyze socially optimal policies under these conditions. We characterize key structural properties in each case, and consider how the government can use these results to decide on the compensation level for private services, and the investment on capacity expansion in public services. 3 - Admission Control in an Intensive Care Unit with Readmissions Faruk Akin, Rumelfeneri Mah., Rumelifeneri Yolu, Sariyer, Istanbul, 34450, Turkey, Koc University, Koc University, Rumelifeneri Mah. Rumelifeneri Yolu, Sariyer, Istanbul, 34450, Turkey, Lerzan E. Ormeci We consider an Intensive Care Unit (ICU) where we focus on the effects of early discharge decisions and possible readmissions on hospital bed management. The system may admit, reject or admit an arriving patient by early discharging a current patient in the ICU. To represent such a setting, we develop a discrete-time Markov Decision Process (MDP) with the aim of minimizing the total expected - discounted cost over an infinite horizon. We investigate the structure of the optimal admission control policy and propose some heuristic policies and evaluate their performances with respect to the optimal policy, which results from solving the MDP formulation. n TA51 North Bldg 231B Joint Session OMS/Practice Curated: Scheduling with Applications Emerging Topic: Project Management and Scheduling, in Memory of Joe Leung, Emerging Topic Session Chair: Marc E. Posner, Ohio State University, 296 Baker Systems Engineering, 1971 Neil Avenue, Columbus, OH, 43210-1271, United States 1 - AGV Control in Large-scale Parallel Transshipment Container Terminal Qitong Zhao, National University of Singapore, Singapore, Chenhao Zhou, Lee Loo Hay The AGV system in transshipment container terminal is characterized by a very large number of AGVs and complicated traffic conditions. To ensure deadlock- and conflict-free routing of the AGVs, we propose a modular concept, allowing the AGV control to be divided into two subproblems, the travel module generation problem and the inner module routing and scheduling problem. These two subproblems are integrated and tested in our discrete event simulation platform. Visualization of the solutions validate the deadlock- and conflict-free movements and numerical results show the efficiency of this two-stage event- trigger approach. 2 - AGV Routing in the Parallel Mega Automated Container Terminal Based on a Two-layer Network Structure Chew Ek Peng, National University of Singapore, Computing Lab, E1-07-26, NUS Department of Eng, Singapore, 117578, Singapore, Zhipeng Qiu To avoid conflicts and improve system efficiency in the mega-ACT, we propose an efficient routing scheme for large-scale AGVs based on a two-layer network structure. At the upper layer, a column-generation based algorithm is used in a sector-based graph for an integrated problem, which not only solve the path direction design to determine the directions for the links, but also solve the global routing to decide the sector-based routes for the AGVs. At the lower layer, a path planning algorithm is proposed for multi-AGVs within the sector to determine the real-time paths and schedules for AGVs with the guarantee of no conflicts. Finally, this study has used different cases for algorithm testing, and the results show that the scheme is efficient and effective for the routing of large-scale AGV systems. 3 - A New Approximation Algorithm for Unrelated Parallel Machine Scheduling Problem with Release Dates Ziteng Wang, Assistant Professor, Northern Illinois Universtiy, 590 Garden Road, EB 240, DeKalb, IL, 60115, United States, Zhi Pei, Mingzhong Wan We consider the unrelated parallel machine scheduling problem with release dates. A 4-approximation algorithm is devised and proved in comparison with the 16/3-approximation. The original scheduling problem is divided into several sub- problems based on the release dates. For each sub-problem, a convex quadratic

Supply Chain and Facility Location Sponsored: Energy, Natural Res & the Environment Environment & Sustainability Sponsored Session Chair: Yihsu Chen 1 - Issues and Challenges for Closed Loop Supply Chain Considering of Commodity Value and QCDE Aya Ishigaki, Tokyo University of Science, Tokyo, Japan, Tetsuo Yamada, Ryuta Takashima In recent years, it is known that the environmental impact by the product quality in manufacture and recovery phase and the energy mix (coal, natural gas, nuclear energy, etc.) of electric power changes with selections of the producing countries or the consuming countries. Furthermore, it is necessary to design and manage a supply chain, considering not only the current value of a product or parts but future value. This study discusses about an issue of closed loop supply chain considering commodity value and QCDE (quality, cost, delivery, and environment). 2 - A Mathematical Model for Real-time Pricing of Electricity to Control Supply and Demand in a Smart Community Mihiro Sasaki, Nanzan University, 18 Yamazato, Showa, Nagoya, 466-8673, Japan We consider a smart community consisting of smart houses in which each is equipped with a fuel cell (FC) system, a photovoltaic (PV) system and a power storage. The supplier of electricity (CEMS: Community Energy Management System) presents the electricity price varying with different time, and customers living in smart houses (HEMS: Home Energy Management System) determine their own optimal levels of buying/selling electricity in responding to the time- varying price. We formulate a problem of finding optimal pricing on the condition that each HEMS finds an optimal schedule to minimize its own total cost as a bilevel programming problem. 3 - Analysis for Maritime Transportation of Energy Resources using AIS Data Shigeki Toriumi, Chuo University, 1-23-27 Kasuga, Bunkyo-ku, Tokyo, 112-8551, Japan, Yihsu Chen In this research, we analyze maritime transportation of energy resources using “Automatic Identification System (AIS)” data. The AIS is an automatic tracking system used on ships. Using this data, we can identify each voyage which include origin, destination, route and speed, so on. Furthermore we can produce an animation which represents vessel movement in the world. We evaluate economic efficiency and risk for transportation of energy resources by comparing with our previous research. 4 - Multi-product Pickup and Delivery Supply Chain Design with Cross Dock Location and Direct Shipment Vahid Azizi, Iowa State University, Ames, IA, United States, Guiping Hu The cross docking process is important in supply chain management . Cross docking makes the material flow more efficient and reduces transportation and inventory holding costs and accelerates delivery . . Although important, the decisions of locating cross-docks are considered separately from shipment routing. This paper presents a model that considers cross-dock location, pickup and delivery vehicle routing, and direct shipment together with cross docking. A mixed integer linear programming model has been formulated to address this problem. Computational experiments have been conducted to validate the proposed model. n TA50 North Bldg 231A Healthcare/Service Systems in Applied Probability Sponsored: Applied Probability Sponsored Session Chair: Lerzan E. Ormeci, Koc University, Rumeli Feneri Yolu, Sariyer, Istanbul, 34450, Turkey 1 - Optimal Control Policies in Systems that Include Batch Characteristics Olga Bountali, Southern Methodist University, 4210 Fairmount Street, Apartment 3063, Dallas, TX, 75219, United States, Lerzan E. Ormeci The control of a service system of interest becomes very complicated when the system operates under some notion of batches. The latter, regardless of whether it refers to the arrival or service patterns, creates intricate trade-offs, the resulting impact of whose can be either detrimental or beneficial. We shed more light to this impact by exploring optimal control policies for systems that operate under some notion of batches.

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