Design Of Express Freight Service Network For Comprehensive Transportation Systems

This dissertation analyzes the transportation scheme of express freight regarding route and transportation mode selection.The demand for express freight transportation continues to increase in light of socio-economic growth.To satisfy timelines and demand,it is imperative to build robust integrated transportation systems and optimized routes.Evaluating the characteristics of various express freight transportation modes can effectively improve the efficiency of express freight delivery.Therefore,this dissertation analyzes the integrated transportation system and the service network design based on the fixed routes and timetables of railway and flight schedules.Under the premise of meeting timeliness,safety requirements,and maximizing the company’s interests,the time-space-state network has been employed.To do this,the extant literature on express freight transportation,service network design,and multimodal transport at home and abroad is reviewed.The research gaps have been identified followed by a comprehensive analysis of the transportation costs,carbon emission,and transportation system data incorporating road,railway,and flight.In the optimization link of the express freight transportation scheme,the single origin-destination transportation model is first considered,and a service network design optimization model is formulated based on the dynamic service network.Then,the hybrid particle swarm optimization algorithm is computed according to the complexity of the spatiotemporal-state network and the assignment characteristics of the model.Finally,a small-scale example is used to validate the model and the algorithm.The results show that the algorithm has good stability.To apply the problem in the real world,a multiple OD transportation model was formulated for the express freight transportation service network design.The hybrid particle swarm optimization algorithm is used to solve the examples.The results of the two examples have been compared and analyzed to validate the efficiency of the model.