Optimal policies for inventory systems with priority demand classes

• 成果类型: Article
• 署名作者: Frank, KC; Zhang, RQ; Duenyas, I
• 署名单位: Delft University of Technology; Cornell University; University of Michigan System; University of Michigan
• 刊物名称: OPERATIONS RESEARCH
• ISSN/ISSBN: 0030-364X
• DOI: 10.1287/opre.51.6.993.24923
• 发表日期: 2003
• 页码: 993-1002
• 关键词: inventory/production : policies inventory/production : deterministic/stochastic; inventory/production : approximations/heuristics

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 the option to ration inventory to the stochastic source (i.e., not satisfy all customer demand even though there is inventory in the system). We first characterize the structure of the optimal policy. We show that, in general, the optimal order quantity and rationing policy are state dependent and do not have a simple structure. We then propose a simple policy, called (s, k, S) policy, where s and S (ordering policy) determine when and how much to order, while k (rationing policy) specifies how much of the stochastic demand to satisfy. We report the results of a numerical study, which shows that this simple policy works extremely well and is very easy to compute.