Research On Inventory Routing Problem For Fresh Agricultural Product With Demand Classes

In recent years, both of the demand for fresh agricultural product and the size of the industry are increasing. The cost of the inventory management and distribution account for the largest proportion of the logistics cost, which are also related to the safety and freshness of the fresh agricultural product.This paper addresses the inventory routing problem of the fresh agricultural product distribution, where a central planner is to find optimal inventory control strategy and distribution program. In this case, the vender manages inventory. This paper studies the following three aspects.Firstly, we introduce the concept and characteristics of fresh agricultural product, and the related concepts of inventory routing problem. The problem is classified into certain demand and stochastic demand according to the retailer’s demand. The hypothesis, cost structure of objective function and constraint condition in both cases is studied to find out the difference of above aspects between general inventory routing problem and the problem of fresh agricultural product.Secondly, based on the above analysis, we study the formulate a nonlinear programming model in the case of certain demand, whose objective function includes the inventory cost, distribution cost, shortage cost and time penalty cost. A two-stage solution method is used to solve the model. We divide the inventory routing problem into two sub problems to solve, which are distribution and inventory problems.When dealing with the inventory problem, we formulate an inventory controlling model considering the deterioration rate. Then we can get the most optimal distribution volume. When dealing with the distribution problem, we Consider the distribution vehicle capacity, time windows for each retailer, a vehicle routing model is built, which can be solved by genetic algorithms. Then we can get the path and vehicle programs. After getting the initial solution, the method of advance distribution is used to adjust it to obtain the reasonable delivery vehicle and vehicle path arrangements.Finally, we study the construction and solving method of the inventory routing problem with stochastic demand model, which is classified into randomly scattered demand and continuous demand. As retailers demand uncertainty, the total system cost consists of all the costs above and shortage cost and spoiled cost. A inventory routing problem model is built based on the costs. The solving method is as same as the one of certain demand model. At the same time, we take the problem in two conditions as numerical examples and then developing genetic algorithms to solve it.