Operations Research

最新文章

• Sequential Resource Allocation for Nonprofit Operations AI翻译
  作者：Lien, Robert W.; Iravani, Seyed M. R.; Smilowitz, Karen R.
  作者单位：Northwestern University
  摘要：This paper studies a sequential resource allocation problem motivated by distribution operations of a nonprofit organization. The alternate objectives that arise in nonprofit (as opposed to commercial) operations lead to new variations on traditional problems in operations research and inventory management. Specifically, we consider the problem of distributing a scarce resource to meet customers' demands that are observed sequentially. An allocation policy that seeks to maximize profit may lea...
• On Markov Equilibria in Dynamic Inventory Competition AI翻译
  作者：Olsen, Tava Lennon; Parker, Rodney P.
  作者单位：University of Auckland; University of Chicago
  摘要：We provide a review of the types of equilibria typically found in operations management inventory papers and a discussion on when the commonly used stationary infinite-horizon (open-loop) equilibrium may be sufficient for study. We focus particularly on order-up-to and basestock equilibria in the context of inventory duopolies. We give conditions under which the stationary infinite-horizon equilibrium is also a Markov perfect (closed-loop) equilibrium. These conditions are then applied to thre...
• One-Machine Sequencing to Minimize Total Tardiness: A Fourth Theorem for Emmons AI翻译
  作者：Kanet, John J.
  作者单位：University System of Ohio; University of Dayton
  摘要：In 1969 H. Emmons provided three theorems (Emmons 1-3) for determining precedence relations between pairs of jobs for the single-machine tardiness problem. We show here a fourth straightforward theorem that uses the information when the jobs in the pair are both known to precede a third job in an optimum sequence. The new theorem augments the three Emmons theorems and is shown to be a generalization of a theorem by Elmaghraby.
• On the Performance of Sparse Process Structures in Partial Postponement Production Systems AI翻译
  作者：Chou, Mabel C.; Chua, Geoffrey A.; Zheng, Huan
  作者单位：National University of Singapore; Nanyang Technological University; Shanghai Jiao Tong University
  摘要：Production postponement, the strategy to hold reserved production capacity that can be deployed based on actual demand signals, is often used to mitigate supply-demand mismatch risk. The effectiveness of this strategy depends crucially on the ease, or flexibility, in deploying the reserved capacity to meet product demands. Existing literature assumes that the reserved capacity is fully flexible, i.e., capable of being deployed to meet the demand of any item in a multiproduct system. Little is ...
• A Mean-Risk Model for the Traffic Assignment Problem with Stochastic Travel Times AI翻译
  作者：Nikolova, E.; Stier-Moses, N. E.
  作者单位：University of Texas System; University of Texas Austin; Texas A&M University System; Texas A&M University College Station; Columbia University; Universidad Torcuato Di Tella; Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET)
  摘要：Heavy and uncertain traffic conditions exacerbate the commuting experience of millions of people across the globe. When planning important trips, commuters typically add an extra buffer to the expected trip duration to ensure on-time arrival. Motivated by this, we propose a new traffic assignment model that takes into account the stochastic nature of travel times. Our model extends the traditional model of Wardrop competition when uncertainty is present in the network. The focus is on strategi...
• Scheduled Service Network Design for Freight Rail Transportation AI翻译
  作者：Zhu, Endong; Crainic, Teodor Gabriel; Gendreau, Michel
  作者单位：University of Quebec; University of Quebec Montreal; Universite de Montreal; University of Quebec; University of Quebec Montreal; Universite de Montreal; Polytechnique Montreal; Universite de Montreal; Polytechnique Montreal
  摘要：This paper addresses the scheduled service network design problem for freight rail transportation. The proposed model integrates service selection and scheduling, car classification and blocking, train makeup, and routing of time-dependent customer shipments based on a cyclic three-layer space-time network representation of the associated operations and decisions and their relations and time dimensions. This paper also proposes a matheuristic solution methodology integrating slope scaling, a d...
• Computational Methods for Risk-Averse Undiscounted Transient Markov Models AI翻译
  作者：Cavus, Ozlem; Ruszczynski, Andrzej
  作者单位：Ihsan Dogramaci Bilkent University; Rutgers University System; Rutgers University New Brunswick
  摘要：The total cost problem for discrete-time controlled transient Markov models is considered. The objective functional is a Markov dynamic risk measure of the total cost. Two solution methods, value and policy iteration, are proposed, and their convergence is analyzed. In the policy iteration method, we propose two algorithms for policy evaluation: the nonsmooth Newton method and convex programming, and we prove their convergence. The results are illustrated on a credit limit control problem.
• Fabrication-Adaptive Optimization with an Application to Photonic Crystal Design AI翻译
  作者：Men, Han; Freund, Robert M.; Nguyen, Ngoc C.; Saa-Seoane, Joel; Peraire, Jaime
  作者单位：Massachusetts Institute of Technology (MIT); Massachusetts Institute of Technology (MIT)
  摘要：It is often the case that the computed optimal solution of an optimization problem cannot be implemented directly, irrespective of data accuracy, because of either (i) technological limitations (such as physical tolerances of machines or processes), (ii) the deliberate simplification of a model to keep it tractable (by ignoring certain types of constraints that pose computational difficulties), and/or (iii) human factors (getting people to do the optimal solution). Motivated by this observatio...
• Integral Simplex Using Decomposition for the Set Partitioning Problem AI翻译
  作者：Zaghrouti, Abdelouahab; Soumis, Francois; El Hallaoui, Issmail
  作者单位：Universite de Montreal; Universite de Montreal; Polytechnique Montreal
  摘要：Since the 1970s, several authors have studied the structure of the set partitioning polytope and proposed adaptations of the simplex algorithm that find an optimal solution via a sequence of basic integer solutions. Balas and Padberg in 1972 proved the existence of such a sequence with nonincreasing costs, but degeneracy makes it difficult to find the terms of the sequence. This paper uses ideas from the improved primal simplex to deal efficiently with degeneracy and find subsequent terms in t...
• When to Use Speedup: An Examination of Service Systems with Returns AI翻译
  作者：Chan, Carri W.; Yom-Tov, Galit; Escobar, Gabriel
  作者单位：Columbia University; Technion Israel Institute of Technology; Kaiser Permanente
  摘要：In a number of service systems, there can be substantial latitude to vary service rates. However, although speeding up service rate during periods of congestion may address a present congestion issue, it may actually exacerbate the problem by increasing the need for rework. We introduce a state-dependent queuing network where service times and return probabilities depend on the overloaded and underloaded state of the system. We use a fluid model to examine how different definitions of overload...