Optimization Design Of Express Shipment Service Network Considering Multi-period Transport Tasks

The service network is the carrier of express shipment and determines an express company's service capability and service level.In recent years,with a large number of capitals flowing into the express market,considering the operation cost and service level,how to seize the environmental advantage of increasing business volume and optimize the service network are key issues for express companies.Therefore,the optimization design of service network is of great significance to the long-term development of express companies.This thesis focuses on the optimization design of express shipment service network considering multi-period transport tasks.The optimization design of express shipment service network refers to optimizing the network structure and operation decision-making of the original service network by investing a certain construction cost.Firstly,this thesis analyzes the service network structure,travelling process and the optimization strategies,evaluation index and influencing factors of the optimization design of express shipment service network under the background of increasing business volume.According to the decision-making level,the optimization design of service network problem is a bi-level problem,which is divided into the strategic level-optimization design of service network structure and the tactical leveloptimization design of service network operation.Then,for the upper level of optimizing the service network structure,the objective is to maximize the benefit-cost ratio,which means the economic benefits brought by the unit construction cost of the optimization of the network structure,and to decide the optimal scheme of opening direct routes and hub expansion.For the lower level of optimizing the service network operation problem,the objective is to minimize the total operation cost,and the routing and vehicle scheduling decision of multiperiod transportation tasks in the network structure optimization decision horizon are considered.Then the bi-level model structure is constructed and the bi-level genetic algorithm is designed to solve the problem.Finally,the experiment of empirical strategy comparison,single-level model comparison and influence factor analysis are designed to verify the validity of the model and algorithm,the necessity of bi-level model structure and the optimal service network optimization design decision can be obtained by the model and algorithm when the parameters are changed.In this thesis,the optimization design problem of express shipment service network considering multi-period transport tasks is proposed.Considering the interaction between the optimization of service network structure and operation,a bi-level optimization model is established and provide a new solution for the optimization design problem of express shipment service network.