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作者：Desaulniers, Guy
作者单位：Universite de Montreal; Polytechnique Montreal; Universite de Montreal
摘要：This paper addresses the split-delivery vehicle routing problem with time windows (SDVRPTW) that consists of determining least-cost vehicle routes to service a set of customer demands while respecting vehicle capacity and customer time windows. The demand of each customer can be fulfilled by several vehicles. For solving this problem, we propose a new exact branch-and-price-and-cut method, where the column generation subproblem is a resource-constrained elementary shortest-path problem combine...
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作者：Shlakhter, Oleksandr; Lee, Chi-Guhn; Khmelev, Dmitry; Jaber, Nasser
作者单位：University of Toronto; University of Toronto
摘要：We study the general approach to accelerating the convergence of the most widely used solution method of Markov decision processes (MDPs) with the total expected discounted reward. Inspired by the monotone behavior of the contraction mappings in the feasible set of the linear programming problem equivalent to the MDP, we establish a class of operators that can be used in combination with a contraction mapping operator in the standard value iteration algorithm and its variants. We then propose ...
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作者：Tezcan, Tolga; Dai, J. G.
作者单位：University of Illinois System; University of Illinois Urbana-Champaign; University System of Georgia; Georgia Institute of Technology
摘要：We consider a class of parallel server systems that are known as N-systems. In an N-system, there are two customer classes that are catered by servers in two pools. Servers in one of the pools are cross-trained and can serve customers from both classes, whereas all of the servers in the other pool can serve only one of the customer classes. A customer reneges from his queue if his waiting time in the queue exceeds his patience. Our objective is to minimize the total cost that includes a linear...
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作者：Zhang, Hao
作者单位：University of Southern California
摘要：This paper presents a novel framework for studying partially observable Markov decision processes (POMDPs) with finite state, action, observation sets, and discounted rewards. The new framework is solely based on future-reward vectors associated with future policies, which is more parsimonious than the traditional framework based on belief vectors. It reveals the connection between the POMDP problem and two computational geometry problems, i.e., finding the vertices of a convex hull and findin...
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作者：Brown, David B.; Smith, James E.; Sun, Peng
作者单位：Duke University
摘要：We describe a general technique for determining upper bounds on maximal values (or lower bounds on minimal costs) in stochastic dynamic programs. In this approach, we relax the nonanticipativity constraints that require decisions to depend only on the information available at the time a decision is made and impose a penalty that punishes violations of nonanticipativity. In applications, the hope is that this relaxed version of the problem will be simpler to solve than the original dynamic prog...
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作者：Denton, Brian T.; Miller, Andrew J.; Balasubramanian, Hari J.; Huschka, Todd R.
作者单位：North Carolina State University; Universite de Bordeaux; University of Massachusetts System; University of Massachusetts Amherst; Mayo Clinic
摘要：The allocation of surgeries to operating rooms (ORs) is a challenging combinatorial optimization problem. There is also significant uncertainty in the duration of surgical procedures, which further complicates assignment decisions. In this paper, we present stochastic optimization models for the assignment of surgeries to ORs on a given day of surgery. The objective includes a fixed cost of opening ORs and a variable cost of overtime relative to a fixed length-of-day. We describe two types of ...
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作者：Chen, Zhi-Long
作者单位：University System of Maryland; University of Maryland College Park
摘要：In many applications involving make-to-order or time-sensitive (e.g., perishable, seasonal) products, finished orders are often delivered to customers immediately or shortly after the production. Consequently, there is little or no finished product inventory in the supply chain such that production and outbound distribution are very intimately linked and must be scheduled jointly to achieve a desired on-time delivery performance at minimum total cost. Research on integrated scheduling models o...
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作者：Tardif, Valerie; Tayur, Sridhar; Reardon, James; Stines, Reid; Zimmerman, Pete
作者单位：Deere & Company
摘要：In 2004, Deere & Company's Commercial & Consumer Equipment Division (C&CE) engaged in a new logistics initiative to further enhance its outbound distribution network. The goal was to offer faster and more reliable replenishment to 2,500 North American independent dealers while keeping logistics costs in check by deploying different tactics during the peak (February-July) and offpeak (August-January) selling and shipping seasons. Deere and SmartOps worked together under a shared reward contract...
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作者：Fibich, Gadi; Gibori, Ro'i
作者单位：Tel Aviv University
摘要：We explicitly calculate the aggregate diffusion dynamics in one-dimensional agent-based models of adoption of new products, without using the mean-field approximation. We then introduce a clusters-dynamics approach, and use it to derive an analytic approximation of the aggregate diffusion dynamics in multidimensional agent-based models. The clusters-dynamics approximation shows that the aggregate diffusion dynamics does not depend on the average distance between individuals, but rather on the ...
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作者：Hora, Stephen C.
作者单位：University of Southern California; University of Southern California
摘要：It is shown how infinite sequences of densities with defined properties can be used to evaluate the expected performance of mathematical aggregation rules for elicited densities. The performance of these rules is measured through the average variance, calibration, and average Brier score of the aggregates. A general result for the calibration of the arithmetic average of densities from well-calibrated independent experts is given. Arithmetic and geometric aggregation rules are compared using s...
