Transportation Route Recommendation And Express Network Structure Optimization In Multimodal Transport Network

Multimodal transport is an integral part of the modern logistics system.This thesis is mainly based on the multimodal transport network,building a multimodal transport route optimization model and a express network structure optimization model,on the one hand,to provide the basis to multimodal transport operators for the selection of transportation route,on the other hand,to provide the reference to the express company for the network construction and expanding the scope of business.The main work and results of this thesis are as follows:(1)Taking the lowest cost of the path as the goal,deciding which city to pass through and which transportation mode to adopt,t:he multimodal transport route optimization model is constructed.Based on the traditional multimodal transport model,the model considers the influence of the fixed timetable of each transportation mode on the route optimization,and adds the customer's latest arrival deadline constraint to make the model closer to the actual situation.The correctness of the model is verified by the algorithm.(2)The K shortest path algorithm is designed to solve the multimodal transport route optimization model.Based on the A*algorithm,aiming at the shortcoming that A*algorithm can only find one best path,this thesis proposes an improved K shortest path algorithm,which can continue searching while the original optimal path does not meet the additional constraints,until it finds the path that satisfies the constraints.Example analysis shows that the algorithm can be used in multimodal transport model.(3)The optimization model of express network structure is constructed with the goal of the lowest total network cost.In this thesis,multimodal transport is applied to express network,choosing a way of transportation from highway and aviation with fixed timetable;given the timeliness of express service,add transportation time budget constraints in each path;prevent the node processing slow,capacity constraints are added in each node,the express amount can not exceed the processing ability.The example analysis shows that the model has some practical guiding significance.