The Study Of Temporary Distribution Center Location Under The Vehicle Routing Problem With Fastest Completion Time

The vehicle route problem(VRP)refers to the consideration of various constraints in the delivery of goods and the selection of an appropriate route to complete the set goals.The common vehicle routing problem takes the total distance and cost as an overall goal and plans the corresponding route.In some special cases of distribution and emergency management,it is required to complete the tasks of multiple locations in the shortest time.At this time,completing the tasks in a short time is far more important than the shortest route and the reduction of logistics costs.The location of the distribution center uses cost as the optimal target,and it reflects the vehicle route problem that compares the different location sites to complete the distribution tasks for all target demand points,and at the same time,the distribution cost is the lowest.However,compared to the shortest time of distribution tasks,the location of the distribution center often does not meet the goal of the shortest time delivery.In addition to finding a suitable distribution route,the method of achieving the fastest delivery can also be set to provide an organic supplement to the temporary distribution center that is different from the distribution center.The provision of temporary distribution centers can cover areas where distribution costs are higher in some distribution centers.According to the size of the service area demand and the choice of vehicle path,some of the vehicle cargo can be allocated to the temporary distribution center to improve the time efficiency of the overall logistics distribution process.Integrating site selection and vehicle routing,problem solving belongs to the category of location-routing(LRP).Among them,the vehicle routing problem is converted into a multi-vehicle vehicle routing problem(MDVRP)due to the joining of temporary distribution centers.With the increase of distribution points,the problem of vehicle routing is gradually transformed into an NP-hard problem.The commonly used solution to this combinatorial explosion problem is to use a heuristic algorithm to solve the problem.The ant colony algorithm is a metaheuristic algorithm that continuously optimizes the path in the graph with certain probabilities.Combining with the actual problem solving,the model part of the ant colony algorithm is modified to use the dynamic programming method to solve the shortest time for each random path,and this time is used as part of the path selection probability parameter selection to find the optimal solution.Firstly,the problem of location of temporary distribution center is introduced.Then the dynamic model is used to construct the distribution model that solves the shortest time according to the preset combination order of distribution points.The model is placed into a variant ant colony algorithm and distributed to all the alternative temporary distribution centers.The distribution time of the plans is compared.Finally,an example of calculating the location of the temporary distribution center for the shortest delivery time is provided in conjunction with the addresses of some convenient points and their distribution centers of the chain store of Tangjiu,Taiyuan.