Research On The Optimization Of The Multiple Routes Of Express Transportation With Time Constraints

China's economy has shifted from a stage of rapid growth to a new stage of highquality development.As a basic industry for the development of the national economy,China's logistics industry still has problems such as high cost,low efficiency,and serious waste of resources.Especially the express delivery industry,which has a single mode of transport and relies heavily on road transport,fails to fully utilize the various modes of transport,Cost,green and other advantages.The combination of multiple modes of transportation has been widely used in the express delivery industry in developed countries due to its advanced,efficient and energy-saving features,but it is still in the primary stage of development in China.The rapid development of China's civil aviation and high-speed rail provides the basic conditions for the combination of multiple modes of express delivery.Therefore,in the operation of express delivery business,it is of great theoretical significance and practical value to give full play to the advantages of each mode of transportation and scientifically and rationally formulate a plan for express transportation routes.The research work of this article is as follows:(1)Research on the optimization of single order multi-transport mode combined route with time constraints.This paper takes the transportation time limit as a hard constraint and constructs a mathematical programming model that takes the sum of transportation cost,transshipment cost and carbon emission cost as the minimum objective function.Aiming at the constrained shortest path problem,an ant colony algorithm mixed with local optimization strategy is designed.In terms of the construction of calculation examples,three types of calculation examples with different scales are designed,and different transportation time limits are set for each calculation example.By comparing with Dijkstra algorithm based on branch and bound,the performance of the hybrid ant colony algorithm is verified.(2)Research on multi-order and multi-transport combined route optimization problem with time constraints.Expand the single order in the above problem to multiple orders,and increase the transportation capacity constraints.On the basis of considering time constraints and transportation capacity constraints,a multi-order and multi-transport combined route optimization problem with service time constraints is proposed,a mathematical programming model is constructed,and MSAU algorithm and hybrid ant colony algorithm are respectively designed to solve.The MSAU algorithm uses the Dijkstra algorithm based on branch and bound to generate the constrained shortest path of orders one by one.Seven local optimization strategies are designed in the hybrid ant colony algorithm.By constructing a set of calculation examples with different scales or orders,the experimental comparison verifies the performance of the MSAU algorithm and the hybrid ant colony algorithm.The results show that the MSAU algorithm is more effective when processing small-scale studies,while the hybrid ant colony algorithm performs better when processing larger-scale studies.There are 22 pictures,30 tables,and 75 references in the paper.