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作者：Margot, F; Queyranne, M; Wang, YG
作者单位：Carnegie Mellon University; University of British Columbia
摘要：We present an in-depth theoretical, algorithmic, and computational study of a linear programming (LP) relaxation to the precedence constrained single-machine scheduling problem 1\prec\Sigma(j)w(j)C(j) to minimize a weighted sum of job completion times. On the theoretical side, we study the structure of tight parallel inequalities in the LP relaxation and show that every permutation schedule that is consistent with Sidney's decomposition has total cost no more than twice the optimum. On the alg...
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作者：Frank, KC; Zhang, RQ; Duenyas, I
作者单位：Delft University of Technology; Cornell University; University of Michigan System; University of Michigan
摘要：We consider a periodic review inventory system with two priority demand classes, one deterministic and the other stochastic. The deterministic demand must be met immediately in each period. However, the units of stochastic demand that are not satisfied during the period when demand occurs are treated as lost sales. At each decision epoch, one has to decide not only whether an order should be placed and how much to order, but also how much demand to fill from the stochastic source. The firm has...
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作者：Nagel, K; Wagner, P; Woesler, R
作者单位：Swiss Federal Institutes of Technology Domain; ETH Zurich; Helmholtz Association; German Aerospace Centre (DLR)
摘要：Certain aspects of traffic flow measurements imply the existence of a phase transition. Models known from chaos and fractals, such as nonlinear analysis of coupled differential equations, cellular automata, or coupled maps, can generate behavior which indeed resembles a phase transition in the flow behavior. Other measurements point out that the same behavior could be generated by geometrical constraints of the scenario. This paper looks at some of the empirical evidence, but mostly focuses on...
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作者：Denizel, M; Usdiken, B; Tuncalp, D
作者单位：Sabanci University
摘要：With the aim of contributing to the debate around OR/MS as a discipline, this study provides a historical comparative investigation of publicly available knowledge production in the field. The empirical investigation is based on a content analysis of 300 randomly selected articles from six major journals in the field. We have found: (1) since the late 1950s to the present day there has been no significant change in the types of published research in OR/MS in North America; (2) from the late 19...
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作者：Fibich, G; Gavious, A; Lowengart, O
作者单位：Tel Aviv University; Ben-Gurion University of the Negev; Ben-Gurion University of the Negev
摘要：Models in marketing with asymmetric reference effects lead to nonsmooth optimization problems and differential games which cannot be solved using standard methods. In this study, we introduce a new method for calculating explicitly optimal strategies, open-loop equilibria, and closed-loop equilibria of such nonsmooth problems. Application of this method to the case of asymmetric reference-price effects with loss-aversive consumers leads to the following conclusions: (1) When the planning horiz...
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作者：Lee, CY; Çetinkaya, S; Jaruphongsa, W
作者单位：Hong Kong University of Science & Technology; Texas A&M University System; Texas A&M University College Station; National University of Singapore
摘要：This paper presents a model for computing the parameters of an integrated inventory replenishment and outbound dispatch scheduling policy under dynamic demand considerations. The optimal policy parameters specify (i) how often and in what quantities to replenish the stock at an upstream supply chain member (e.g., a warehouse), and (ii) how often to release an outbound shipment to a downstream supply-chain member (e.g., a distribution center). The problem is represented using a two-echelon dyna...
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作者：Scheller-Wolf, A
作者单位：Carnegie Mellon University
摘要：In this paper we establish the weakest known sufficient conditions for the existence of stationary delay moments in FIFO GI/GI/s queues, for s greater than or equal to 2. These conditions involve not only the service time distribution, as in the classic Kiefer and Wolfowitz conditions, but also the interplay of the traffic intensity and the number of servers in the queue. We then prove the necessity of our conditions for a large class of service times having finite first, but infinite alphath,...
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作者：Yang, M; Leung, JYT
作者单位：New Jersey Institute of Technology; New Jersey Institute of Technology
摘要：We study a variant of the classical bin-packing problem, the ordered open-end bin-packing problem, where first a bin can be filled to a level above 1 as long as the removal of the last piece brings the bin's level back to below 1 and second, the last piece is the largest-indexed piece among all pieces in the bin. We conduct both worst-case and average-case analyses for the problem. In the worst-case analysis, pieces of size 1 play distinct roles and render the analysis more difficult with thei...
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作者：Granot, D; Sosic, G
作者单位：University of British Columbia; University of Southern California
摘要：We present and study a three-stage model of a decentralized distribution system consisting of n retailers, each of whom faces a stochastic demand for an identical product. In the first stage, before the demand is realized, each retailer independently orders her initial inventory. In the second stage, after the demand is realized, each retailer decides how much of her residual supply/demand she wants to share with the other retailers. In the third stage, residual inventories are transshipped to...
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作者：Hochbaum, DS
作者单位：University of California System; University of California Berkeley
摘要：The inverse spanning-tree problem is to modify edge weights in a graph so that a given tree T is a minimum spanning tree. The objective is to minimize the cost of the deviation. The cost of deviation is typically a convex function. We propose algorithms here that are faster than all known algorithms for the problem. Our algorithm's run time for any convex inverse spanning-tree problem is O(nm log(2) n) for a graph on n nodes and m edges plus the time required to find the minima of the n convex...
