考虑旧产品再制造的周期盘点库存决策

为了确定最优的再制造与制造策略，对有限计划期间的周期盘点库存系统进行研究。在该系统中，计划期间之初有相当多的旧产品，若对这些旧产品全部再制造，得到的再制造品将满足整个计划期间的顾客需求。但是，若旧产品的持有成本超过起动新产品制造的准备成本时，则起动新产品制造更加经济。此时，为满足顾客的需求，将有再制造与制造两种方式并存。针对现有研究假定再制造准备次数和制造准备次数已知的情况下得到的再制造与制造策略不一定是最优的局限，假定再制造准备次数与制造准备次数未知，构建了最小化有限计划期间总成本的库存决策模型。通过构建关于转换期的集合，推导出了不同转换期对应的最小总成本函数及其最优转换期的存在范围。最小总成本是关于转换期及相应最优的再制造准备次数和制造准备次数的函数，提出了一个确定计划期间最优策略的简单算法，并用算例对模型及算法进行验证，得到相应的最优策略及最优总成本。

Periodic Review Inventory Decision-making with Remanufacturing of Used Products

To determine the optimal policy for remanufacturing and manufacturing, a periodic review inventory system for a finite planning horizon is investigated. In this system, there are quite a few used products at the beginning of the horizon, and once these used products are remanufactured, the remanufactured products will satisfy the demand of the customers for the whole horizon. However, when the holding cost of used products is greater than the setup cost of remanufacturing, it is more economical to remanufacture. Then, the two modes, i.e. remanufacturing and manufacturing, will coexist to satisfy the demand of the customers. Due to the limitation that the policy for remanufacturing and manufacturing may not be optimal when the numbers of remanufacturing and manufacturing setup are given in the past literatures, it is assumed that the numbers of remanufacturing and manufacturing setup are unknown and the inventory decision-making model to minimize the total cost for the finite planning horizon is formulated. Using the sets on the switching period, the minimum total cost functions corresponding to different switching periods and the areas that the optimal switching period possibly appears are derived. The minimum total cost is a function with respect to the switching period and the corresponding optimal numbers of remanufacturing and manufacturing setup, and a simple algorithm is presented to determine the optimal policy over the planning horizon, the model and the algorithm are validated by a numerical example, and the corresponding optimal policy and total cost are obtained.