Informs Annual Meeting 2017

WB61

INFORMS Houston – 2017

WB61

2 - Approximation Methods to Analyze Merge Configurations of Open Queueing Networks with Multiple Servers and Blocking Guy L.Curry, Senior Professor, Texas A&M.University, MS-3131, College Station, TX, 77843, United States, g-curry@tamu.edu Open queueing networks that contain merge configurations with blocking result in combinatorial sequencing for waiting jobs to enter the merge queue. Lee and Pollock developed a methodology for decomposing the system and analyzing individual queues. The merge queue with after-service blocking of the predecessor machines can be aggregated and the probabilities easily calculated. The Lee and Pollock approach is extended in this paper to multiple machines with non-identical servers. 3 - Queueing System with Feedback Vacations and Disasters A queueing system with batch Poisson arrivals and Bernoulli feedback which is subject to disasters and repairs is analyzed. Further, the server, when idle, takes repeated vacations of random length. We analyze this system using the supplementary variables technique and we obtain the probability generating function of the stationary queue length distribution, the Laplace transform of the busy period distribution. We also provide expressions for performance measures and we present a delicate method to derive waiting times. 4 - Waiting Time Analysis in Network of Polling Queues Ravi Suman, University of Wisconsin-Madison, 2302 University Avenue, Apartment #207, Apartment #207, Madison, WI, 53726, United States, rsuman@wisc.edu, Ananth Krishnamurthy We analyze a network of polling queues with multiple products and multiple stations. We assume that external arrivals to the network follow a Poisson process, and that each station can be modelled as single server queue with exponentially distributed service times for each product. We establish a stochastic model to analyze this system and develop a procedure to estimate mean waiting times at each station under different service disciplines. 5 - A New Look on the Shortest Queue System with Jockeying We introduce a Markov queueing system with Poisson arrivals, exponential services and jockeying between two parallel and equivalent servers. An arriving customer admits to the shortest line, (when the lines are equal the customer admits to any line with probability 1/2). Every transition, of only the last customer in line, from the longer line to the shorter line is accompanied by a certain fixed cost. Thus, a transition from the longer queue to the shorter queue occurs whenever the difference between the lines reaches a certain discrete threshold (T =2,3, ...). In this study we focus on the stochastic analysis of the number of transitions of an arbitrary customer. 370D Repair Planning and Disruption Management Sponsored: Transportation Science & Logistics Sponsored Session Chair: Kazuaki Okubo, Ehime University, Matsuyama, 0, Japan, okubo@cee.ehime-u.ac.jp 1 - An MIP Approach for Planning Pothole Repairs Fatemeh Aarabi, University at Buffalo, 4280 Chestnut Ridge Road, Apt F3, Amherst, NY, 14228, United States, faarabi@buffalo.edu, Jee Eun Kang, Rajan Batta Potholes degrade the functionality of roadway networks (throughput of traffic flow) in addition to concerns of safety and vehicle damages. A suitable repair planning strategy is developed to minimize total traffic flow throughput degraded over time. The proposed MIP model determines the optimal decisions of repair segment, type, and timing given limited resources. We apply the proposed model to a New York City case study. 2 - A Reliability based Planning Model for Bridge Maintenance under Different Management Agencies Kazuaki Okubo, Associate Professor, Ehime University, 3 Bunkyo Machi, Matsuyama City, Matsuyama, 790-8577, Japan, okubo@cee.ehime-u.ac.jp, Pang-jo Chun, Haruna Suzuki We develop a bridge maintenance and repair planning model based on the traffic assignment model with variable demand. The objective is minimizing social cost, the sum of road network user cost, maintenance and repair cost , with considering potential bridge failures and the differences in management agencies of each bridge. We show the numerical results by using the bridge inspection data in Shikoku region, Japan. Rachel Ravid, Dr, ORT Braude College, Doar Na Bikat Beit Hakerem, Kamon, 20112, Israel, ravidmichael@gmail.com WB63 George Mytalas, CUNY, New York, NY, United States, george.mytalas@brooklyn.cuny.edu, Michael A. Zazanis

370B Finance, Banking and Insurance Contributed Session Chair: Markku Kallio, Aalto University School of Business, Helsinki, Finland, markku.kallio@aalto.fi 1 - Evaluating Size Effect on Cost Inefficiency of Commercial Banks with DEA Jean-Raymond Fontin, Student, National Taiwan University of Science and Technology, No.43, Sec. 4, Keelung Rd., Da‘an Dist.,, Taipei City, 10607, Taiwan, d10501812@mail.ntust.edu.tw This study evaluates the determinants of size effect on cost inefficiency of commercial banks in low income countries using undesirable outputs DEA models. It covers a total of 9 countries and 108 banks over the period of 2013- 2015. The results have shown that small banks are more efficient, and also support the “skimping” hypothesis; contrary to what most researchers have found. Small inefficient banks suffer from bad management problem that leads to cost inefficiency. Aggressive and well-capitalized small inefficient banks devote excessive resources to optimize their asset quality management and increase their investment portfolio to compensate for their costs. 2 - Financing Multiple Suppliers in Assembly Systems Buyer vs. Bank Financing Shiming Deng, Professor, Huazhong University of Science and Technology, 4318 Collins Court, Apt 5, Mountain View, CA, 94040, United States, dengsm@gmail.com, Chaocheng Gu, Gangshu Cai, Li Yanhai This paper compares buyer finance with bank finance in a supply chain with one assembler and multiple heterogeneous capital-constrained component suppliers. We characterize the equilibrium solutions for different financing schemes. We show that in buyer finance the assembler should charge the suppliers the lowest possible interest rate, which may be even below its own unit capital cost. The assembler may offer buyer finance even if its own unit capital cost is higher than banks’ risk-free interest rate. We also identify the conditions under which buyer finance is better than bank finance, and demonstrate how initial capitals, costs, and heterogeneity affect the selection of financing scheme. 3 - Cooperative Mitigation of Contagion in Financial Networks Markku Kallio, Professor (emeritus), Aalto University School of Business, Pohjoiskaari 17 D.17, Helsinki, FIN-00200, Finland, markku.kallio@aalto.fi, Aein Khabazian We examine the financial network as a cooperative game. Governments can act as facilitators enforcing incentives for banks to cooperate and prevent the escalation of a financial crisis. To determine the characteristic function of the cooperative game, we develop clearing payment models for alternative coalitions competing in the market and show that the proposed models have unique equilibrium solutions satisfying the clearing conditions. As a solution concept, we use nucleolus which implies a possible subsidizing pattern among the banks. For a demonstration we use major European banks and a scenario which is linked to the adverse economic scenario used in 2016 EU-wide stress testing. 370C Reliability Contributed Session Chair: Rachel Ravid, ORT Braude College, Kamon, Israel, ravidmichael@gmail.com 1 - Bandwidth Sharing with Phase-type File Size Distributions Weina Wang, Postdoc, University of Illinois at Urbana-Champaign, Urbana, IL, United States, weinaw@illinois.edu, Siva Theja Maguluri, R. Srikant, Lei Ying We study a connection-level model for bandwidth sharing among data transfer flows due to Massoulié and Roberts, where file sizes have phase-type distributions and proportionally fair bandwidth allocation is used. We analyze the expected number of files in steady-state by setting the steady-state drift of an appropriately chosen Lyapunov function equal to zero. We obtain asymptotically tight bounds on the expected number of files in the system in the heavy-traffic regime. Our results show that the expected number of files under proportionally fair bandwidth allocation is insensitive to file size distributions, thus complementing the diffusion approximation result of Vlasiou, Zhang, and Zwart. WB62

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