Study On Optimizations Of Inventory Structure In Multi-Echelon Distribution System Based On Products Characteristics

This dissertation studied the optimal theory of multi-echelon distribution system inventory structure from the perspective of product characteristics. Based on the study on service level and cost performance, the inferior position in efficiency, cost, and controllability of present inventory structure of multi-echelon distribution systems was given.The irrational inventory structure would not only debase the efficiency of distribution system ,but also can't meet the request which was lodged by new market environments in value and profit-created performance . On this basis ,it is needed to study how to optimize the analysis , design and improvement of multi-echelon distribution system's inventory structure.At the beginning, this dissertation summarized the international studies in supply chain and distribution system optimization ,on this basis, the overview of the up-to-date research results in multi-echelon system inventory optimization was prompted. Through this overviews, we found that few research in this field focus on product characteristics. But in reality, the product was the important carrier of market environment changing, such as the change of products variety, the change of product life cycle stages, the change of time property of demand, and some change of store and transporting property based on its own characteristics of product. It's very important to study the optimal method in multi-echelon distrution system inventory structure from the perspective of product characteristics. the theoretical meaning of this study in multi-echelon distribution system inventory structure optimization based on product characteristics was prompted.On this basis, the new ideas of this field was put forward, combined with present research results and methods, the main study contents and technical routine was introduced. This study would began from three arrangement:The vertical optimal method of inventory structure would be studied at first, in order to optimize the best restore level in multi-echelon distribution system, secondly, the horizontal optimal method of inventory structure would be studied to optimize the inventory allocation problems,at last, combined with the present distribution system structure modul, the method of selecting rational inventory strucuture modul was given to optimize the restore structure in multi-echelon distribution system.The most works are presented in the following five aspects:Firstly, the main study contents of multi-echelon distribution system inveotory structure optimization based on product characteristics was given.At first, the relation ship between inventory structure optimization and multi-echelon distribution system structure optimization and the relationship between inventory structure optimization and inventory optimistion was studied.It is obviously that the inventory structure optimal study would not study the problem of depot location, capability programming and other distribution optimal prolems, it focused on the inventory contol problems in multi-echelon and multi-depot in distribution system. Without changing the physical structure of distribution system, the inventory structure optimation would resolve the problem of cost and service request through rational inventory arrangement in the ehelons and depots. On this bais, through the analysis of some product characteristics, the relationship between product properties and system structure and performance is prompted and some problems existed in multi-echelon distribution system operating were confirmed, (1) optimize the vertical inventory structure based on product characteristics; (2) optimize the horizon inventory allocation strategy based on demands; (3) confirm the inventory structure in multi-echelon distribution system based on product characteristics.Secondly, the vertical inventory structure optimization based on product characteristics was studied. At first, the optimal inventory control model of multi-echelon distribution system composed by manufacture, distribution centers, retailers and customers ,with random demanding is given. The model's object is minimizing the total cost in distribution system and it is subject to the target service level. Using simulation, the optimal inventory control strategy is resolved, and the effect of some demanding parameters on total cost such as demand quality, fluctuation , and so on. And then, this paper describe the different stage of product life cycle through adjusting service sensitive of product, and a optimal model is built up and resolved by simulation methods. According to the simulation results, the optimal distribution system structure pattern for different product life cycle stage is given.Thirdly, the inventory allocation problems between different inventory depots based on products'demand characteristics and service request is studied. At first, the optimal model of inventory allocation in multi-echelon system is prompted under random demanding when the upper inventory is abundance. The simulation example was used to analysis the effect of change of some product properties to total cost, such as the demanding quantity, target service level, lead time . And then, the optimal model of inventory allocation used fuzzy set theory is prompted the upper inventory is unabundance. Through adjusting the weight of cost and service , the method of adjusting inventory allocation strategy when the product had been changed.Fourthly, based on the study above all, and combined with the existing distribution system inventory structure in reality, the relationship between product characteristics with distribution system and performance was given, and the selecting frame model of distribution system inventory structure based on product characteristics was prompted. Through this model, the manager can select adaptive distribution system structure before designing new system, or check the rationality of existing system, and promote the distribution mode when the market circumstance changed, such as when some new kinds of products enter into the market. Fifthly, the case study in different industry is prompted. Two kinds of distribution systems were studied. The first one which was in medicine wholesaler industry was used to check out the optimal design methods of this study, and the second one of cigeratte saling industry was used to check out eht optimal improvement methods of this study. The analysis and optimization of these cases indicated that the study was reasonable and the result was effective and economic.Compared with the present studies, the optimization of inventory structure was focused on, and this dissertation offered a new persptive from the properties of product that study the optimization of inventory structure in a multi-echelon distribution system. The advice which could be given to the following study was (1) amplified the number of parameters which describe the product's properties in a quantitive way; (2) amplified the mumber of echelons in the vertical echelon inventory optimizaiotn and in the horizontal depot inventory optimization;(3) put some other parameters expect cost and service level into the horizontal inventory opitimization with fuzzy set theory.