Operations Research

最新文章

• Optimal selection of a connected reserve network AI翻译
  作者：Önal, H; Briers, RA
  作者单位：University of Illinois System; University of Illinois Urbana-Champaign; Edinburgh Napier University
  摘要：Spatial considerations are important in conservation reserve design. A particularly important spatial requirement is the connectivity of selected sites. Direct connections between reserve sites increase the likelihood of species persistence by allowing dispersal and colonization of other areas within the network without species having to leave the reserve. The conventional set-covering and maximal-covering formulations of the reserve selection problem assume that species representation is the ...
• Optimal inventory policy with two suppliers AI翻译
  作者：Fox, EJ; Metters, R; Semple, J
  作者单位：Southern Methodist University; Emory University
  摘要：We analyze a periodic-review inventory model where the decision maker can buy from either of two suppliers. With the first supplier, the buyer incurs a high variable cost but negligible fixed cost; with the second supplier, the buyer incurs a lower variable cost but a substantial fixed cost. Consequently, ordering costs are piecewise linear and concave. We show that a reduced form of generalized (s, S) policy is optimal for both finite and (discounted) infinite-horizon problems, provided that ...
• Requirements planning with pricing and order selection flexibility AI翻译
  作者：Geunes, J; Romeijn, HE; Taaffe, K
  作者单位：State University System of Florida; University of Florida; Clemson University
  摘要：Past requirements-planning research has typically assumed that the firm's demands are determined prior to production planning. In contrast, we explore a single-stage planning model that implicitly decides, through pricing decisions, the demand levels the firm should satisfy in order to maximize contribution to profit. We briefly discuss solution methods and properties for these problems when production capacities are unlimited. The key result of this work is a polynomial-time solution approach...
• From the Editor AI翻译
  作者：Simchi-Levi, D
  作者单位：Massachusetts Institute of Technology (MIT)
• Area Editors' Statements AI翻译
  作者：Fourer, R; Hazen, GB; Oren, SS; Broadie, MN; Duenyas, I; Song, JS; Simester, D; Kress, M; Ye, YY; Trick, MA; Graves, SC; Zenios, SA; van Ryzin, GJ; Henderson, SG; Kumar, S; Balakrishnan, A; Ball, MO
• Managing patient service in a diagnostic medical facility AI翻译
  作者：Green, LV; Savin, S; Wang, B
  作者单位：Columbia University
  摘要：Hospital diagnostic facilities, such as magnetic resonance imaging centers, typically provide service to several diverse patient groups: outpatients, who are scheduled in advance; inpatients, whose demands are generated randomly during the day; and emergency patients, who must be served as soon as possible. Our analysis focuses on two interrelated tasks: designing the outpatient appointment schedule, and establishing dynamic priority rules for admitting patients into service. We formulate the ...
• Increasing risk and increasing informativeness: Equivalence theorems AI翻译
  作者：Baker, E
  作者单位：University of Massachusetts System; University of Massachusetts Amherst
  摘要：When considering problems of sequential decision making under uncertainty, two of the most interesting questions are: How does the value of the optimal decision variable change with an increase in risk? How does the value of the optimal decision variable change with a more informative signal? In this paper, we show that if the payoff function is separable in the random variable, then one model can simultaneously answer both questions. This result holds for the reaction functions and equilibria...
• Fluid models for multiserver queues with abandonments AI翻译
  作者：Whitt, W
  作者单位：Columbia University
  摘要：Deterministic fluid models are developed to provide simple first-order performance descriptions for multiserver queues with abandonment under heavy loads. Motivated by telephone call centers, the focus is on multiserver queues with a large number of servers and nonexponential service-time and time-to-abandon distributions. The first fluid model serves as an approximation for the G/GI/s + GI queueing model, which has a general stationary arrival process with arrival rate A, independent and iden...
• A stochastic programming approach to power portfolio optimization AI翻译
  作者：Sen, S; Yu, LH; Genc, T
  作者单位：University of Arizona
  摘要：We consider a power portfolio optimization model that is intended as a decision aid for scheduling and hedging (DASH) in the wholesale power market. Our multiscale model integrates the unit commitment model with financial decision making by including the forwards and spot market activity within the scheduling decision model. The methodology is based on a multiscale stochastic programming model that selects portfolio positions that perform well on a variety of scenarios generated through statis...
• Approximation algorithms for problems combining facility location and network design AI翻译
  作者：Ravi, R; Sinha, A
  作者单位：Carnegie Mellon University; University of Michigan System; University of Michigan
  摘要：We present approximation algorithms for integrated logistics problems that combine elements of facility location and transport network design. We first study the problem where opening facilities incurs opening costs and transportation from the clients to the facilities incurs buy-at-bulk costs, and provide a combinatorial approximation algorithm. We also show that the integer-programming formulation of this problem has small integrality gap. We extend the model to the version when there is a b...