变质率呈Weibull分布的一体化三级冷链库存策略研究

An Integrated Three-echelon Inventory Model for Cold Chain Items with Weibull Distribution

本文以有限期内一个生产商、多个分销商和多个零售商组成的冷链系统库存一体化决策为研究内容,建立了考虑可变运输成本、变质率服从三参数Weibull分布的三级冷链库存模型。文章从系统利润最大化的角度确定各个供应链成员的最佳补货策略,在与零售商主导的非一体化决策的对比分析中发现,库存一体化决策带来系统利润增加的同时也牺牲了部分成员的利益。与此同时,通过对变质率参数和运输成本参数的灵敏度分析发现,在运输距离一定的条件下,固定运输成本对最优库存策略的影响较大;在保鲜期一定情况下,变质率的尺度因子对系统总变质成本的影响较大。

Most of the cold chain commodities are perishable goods, such as fruits, vegetables, meats, etc. Product deterioration is usually observed during their normal storage period. Deterioration causes the loss of the commodities＇ utility, which directly increases inventory cost. Hence, it is imperative to study deteriorated inventory. Over the past decade, the inventory control problems have received considerable interest in the literatures, where a two-echelon supply chain system with a single-vendor and a single buyer to minimize the average total costs is discussed. However, few articles revealed the integrated inventory strategy of a multi-echelon supply chain which includes transportation cost. Furthermore, we lack of literatures analyzing how to achieve the win-win situation for the members of the supply chain. This paper establishes an integrated multi-echelon cold chain inventory model in a finite horizon. Firstly, this paper used the three-parameter Weibull distribution to represent the deterioration rate. The existing researches oflen assumed that deterioration occurs as soon as commodities arrive in inventory. In practice, most goods would need to maintain their quality and/or original condition, i.e. no deterioration occurs during that period. Three-parameter Weibull distribution was used to depict a non-instantaneous deteriorating inventory preferably. Secondly, this model established an integrated cold chain inventory model which contains a manufacturer, a multi-distributor, and a multi-retailer in a finite horizon to find the optimal order quantity and duration of the system. This paper assumed that demand rate grows at an exponential rate and transportation cost was a function of the replenishment quantity. Thirdly, the Genetic Algorithms is used for a comparative analysis with the retailer-leading model. The analysis showed that not all of cold chain members can be benefited from the integrated policy. A profit distribution mechanism is deemed necessary for the implementation of an integrated cold chain. In conclusion, this study reveals the compositions of the costs of the three-echelon supply chain and the influence of transportation cost on the total profit. In addition, this study shows that the optimal inventory policy with a single deteriorating item to maximize the total profit can be achieved under an integrated multi-echelon cold chain environment. Lastly, the mathematical model used in this study demonstrates the necessity of cold chain integration.