Operations Research

最新文章

• Patient Streaming as a Mechanism for Improving Responsiveness in Emergency Departments AI翻译
  作者：Saghafian, Soroush; Hopp, Wallace J.; Van Oyen, Mark P.; Desmond, Jeffrey S.; Kronick, Steven L.
  作者单位：Arizona State University; Arizona State University-Tempe; University of Michigan System; University of Michigan; University of Michigan System; University of Michigan; University of Michigan System; University of Michigan; University of Michigan System; University of Michigan
  摘要：Crisis-level overcrowding conditions in emergency departments (EDs) have led hospitals to seek out new patient-flow designs to improve both responsiveness and safety. One approach that has attracted attention and experimentation in the emergency medicine community is a system in which ED beds and care teams are segregated and patients are streamed based on predictions of whether they will be discharged or admitted to the hospital. In this paper, we use a combination of analytic and simulation ...
• A Single-Supplier, Multiple-Retailer Model with Single-Season, Multiple-Ordering Opportunities, and Fixed Ordering Cost AI翻译
  作者：Jain, Apurva; Moinzadeh, Kamran; Zhou, Yong-Pin
  作者单位：University of Washington; University of Washington Seattle; University of Hong Kong
  摘要：In this paper, we discuss the replenishment decision of seasonal products in a two-echelon distribution system consisting of a supplier and multiple retailers. Because of long manufacturing lead time, the supplier orders its entire stock for the season well in advance. The retailers, on the other hand, can replenish their inventory from the supplier throughout the season as demand realizes. Demand at each retailer follows a Poisson process. Each retailer order incurs a fixed cost, and the usua...
• Comparative Statics Analysis of Multiproduct Newsvendor Networks Under Responsive Pricing AI翻译
  作者：Bish, Ebru K.; Zeng, Xin; Liu, Juqi; Bish, Douglas R.
  作者单位：Virginia Polytechnic Institute & State University
  摘要：We propose a novel analytic approach for the comparative statics analysis of multiproduct multiresource newsvendor networks under responsive pricing. Our approach involves exploiting the properties of the primal mathematical programming formulation and of the dual variables and linking those properties to the concept of convex orders and to properties of the underlying demand function. The use of convex orders allows us to establish our main results without restriction to a specific demand dis...
• First in Line Waiting Times as a Tool for Analysing Queueing Systems AI翻译
  作者：Koole, G. M.; Nielsen, B. F.; Nielsen, T. B.
  作者单位：Vrije Universiteit Amsterdam; Technical University of Denmark
  摘要：We introduce a new approach to modelling queueing systems where the priority or the routing of customers depends on the time the first customer has waited in the queue. This past waiting time of the first customer in line, W-FIL, is used as the primary variable for our approach. A Markov chain is used for modelling the system where the states represent both the number of free servers and a discrete approximation to W-FIL. This approach allows us to obtain waiting time distributions for complex...
• Conditional Value-at-Risk and Average Value-at-Risk: Estimation and Asymptotics AI翻译
  作者：Chun, So Yeon; Shapiro, Alexander; Uryasev, Stan
  作者单位：Georgetown University; University System of Georgia; Georgia Institute of Technology; State University System of Florida; University of Florida
  摘要：We discuss linear regression approaches to the estimation of law-invariant conditional risk measures. Two estimation procedures are considered and compared; one is based on residual analysis of the standard least-squares method, and the other is in the spirit of the M-estimation approach used in robust statistics. In particular, value-at-risk and average value-at-risk measures are discussed in detail. Large sample statistical inference of the estimators is derived. Furthermore, finite sample p...
• A Broader View of Designing the Liver Allocation System AI翻译
  作者：Akan, Mustafa; Alagoz, Oguzhan; Ata, Baris; Erenay, Fatih Safa; Said, Adnan
  作者单位：Carnegie Mellon University; University of Wisconsin System; University of Wisconsin Madison; Northwestern University; University of Waterloo; University of Wisconsin System; University of Wisconsin Madison
  摘要：We consider the problem of designing an efficient system for allocating donated livers to patients waiting for transplantation. The trade-off between medical urgency and efficiency is at the heart of the liver allocation problem. We model the transplant waiting list as a multiclass fluid model of overloaded queues, which captures the disease evolution by allowing the patients to switch between classes, i.e., health levels. We consider the bicriteria objective of minimizing total number of pati...
• Bullwhip Effect Measurement and Its Implications AI翻译
  作者：Chen, Li; Lee, Hau L.
  作者单位：Duke University; Stanford University
  摘要：The bullwhip effect, or demand information distortion, has been a subject of both theoretical and empirical studies in the operations management literature. In this paper, we develop a simple set of formulas that describe the traditional bullwhip measure as a combined outcome of several important drivers, such as finite capacity, batch-ordering, and seasonality. Our modeling framework is descriptive in nature as it features certain plausible approximations that are commonly employed in practic...
• Ordering Policies for Periodic-Review Inventory Systems with Quantity-Dependent Fixed Costs AI翻译
  作者：Caliskan-Demirag, Ozgun; Chen, Youhua (Frank); Yang, Yi
  作者单位：Pennsylvania Commonwealth System of Higher Education (PCSHE); Pennsylvania State University; City University of Hong Kong; Zhejiang University
  摘要：We consider a stochastic periodic-review inventory control system in which the fixed cost depends on the order quantity. In particular, we investigate the optimal ordering policies under three fixed cost structures. The first structure is motivated by transportation and production contracts and considers two fixed costs: if the order size is within a specified limit C, then the fixed cost is K-1; otherwise, it is K-2, where K-1 <= K-2. The second structure contains multiple fixed costs in whic...
• Technical Note - On Optimal Policies for Inventory Systems with Batch Ordering AI翻译
  作者：Huh, Woonghee Tim; Janakiraman, Ganesh
  作者单位：University of British Columbia; University of Texas System; University of Texas Dallas
  摘要：We study a periodically reviewed multiechelon inventory system in series such that order quantities at every stage have to be multiples of a given stage-specific batch size. The batch sizes are nested in the sense that the batch size for every stage is an integer multiple of the batch size for its downstream stage. The problem is that of determining the policy that minimizes the expected discounted sum of costs over a finite horizon. The result is that an echelon (R, nQ) policy is optimal when...
• Strategies for a Centralized Single Product Multiclass M/G/1 Make-to-Stock Queue AI翻译
  作者：Abouee-Mehrizi, Hossein; Balcioglu, Baris; Baron, Opher
  作者单位：University of Waterloo; Sabanci University; University of Toronto
  摘要：Make-to-stock queues are typically investigated in the M/M/1 settings. For centralized single-item systems with backlogs, the multilevel rationing (MR) policy is established as optimal and the strict priority (SP) policy is a practical compromise, balancing cost and ease of implementation. However, the optimal policy is unknown when service time is general, i.e., for M/G/1 queues. Dynamic programming, the tool commonly used to investigate the MR policy in make-to-stock queues, is less practica...