Study On Half Open Vehicle Routing Problem In Multi-distribution Center

With the rapid development of global economy and the modern technology, the logistics industry is expanding rapidly in the world. The logistic industry has been became the fundamental industry in the progress of national economic development and it is rather significant to other industry. As the core portion of logistics, the modernization of distribution is the premier condition and remarkable feature of modern logistics. However, with the evolution of e-commerce and internet technology, traditional model of logistics distribution which divided the whole area into several parts is no longer meet the demand of regional distribution. The modern distribution mode of logistics needs to fulfill the custom’s characteristic of regionalization, multi batch of operation and small quantities.In order to meet the demands of logistics distribution under new situation, the paper bring in the half opening vehicle routing problem. What more, based on the sharing of information and resource from multi distribution centers, it established the mode of logistics distribution that could achieve combined transportation across regions. The mode liberated the enterprises that used to fixed area which improved the utilization rate of the vehicle and reduced the transportation costs as well. According to the reality, the paper considered the restrictions of vehicle number and working time limit. And on this basis, the work of the vehicle scheduling scheme and car rental decisions is rather effective and the labor time of workers are guaranteed. At the same time, the thesis also take the requirement of customers into consideration. A soft time windows penalty function was set in the objective functions which satisfy the dual requirements of customers in the quality of service and veracity of delivery time. It could effectively enhance the market competitiveness of logistics enterprises so the mode has great practical value and also strong theoretical significance.Firstly, the paper described the concept of vehicle routing problem and research summary. On the basis of detailed analysis, the thesis studied the standard vehicle routing problem and its extension problems. Meanwhile, the advantages and disadvantages of basic algorithm which used in problem solving were discussed. Secondly, in order to make up the shortcomings of present logistics research in China, the paper introduced the half opening vehicle routing problem with soft time windows and multi distribution centers as a solution to fulfill the demand of modern logistics. Based on the study of characteristics, the paper designed an ant algorithm which using the integral method of solving thought to solve the problem.Thirdly, the paper built the mathematical model of the half opening vehicle routing problem with soft time windows and multi distribution centers. Then it introduced the basic principle of ant colony algorithm and key parameters are briefly discussed. An ant colony algorithm respond to the mathematical model is designed.Finally, examples of different sizes were used to demonstrate that the constructed model and ant algorithm is effective to solve this kind of problems. Through the comparison and analyze of calculations between decomposition method and integral method, it verified that the model and ant algorithm which built were effective. The paper can provide theoretical support for related decisions to solve the problems.