Research On Container Multimodal Transport Path Optimization Under Uncertain Environment

Container multimodal transport has the advantages of long industrial chain,wide driving range,convenience and efficiency,economy,environmental protection,safety and reliability.The development of container multimodal transport is conducive to adjusting the supply side structure of China’s economy,realizing the optimal allocation of factors,expanding transportation supply and giving better play to regional transportation advantages.In recent years,thanks to the "one belt,one road" strategy,container multimodal transport has also ushered in a broad space for development.With the popularization of multimodal transport,customers’ requirements for timeliness and reliability of transportation are also increasing,and the adverse impact of the uncertainty of factors such as transportation time,transportation price and transportation capacity is becoming increasingly prominent.Therefore,to overcome the adverse effects of random factors and formulate a reliable multimodal transport scheme is an important content to improve the service level and enhance the competitiveness of multimodal transport.This thesis focuses on the path optimization of container multimodal transport,adopts the robust optimization approach based on scenario,studies the multimodal transport path optimization problem with uncertain freight demand and transportation time between nodes in order to obtain a robust transportation scheme in an uncertain environment.Firstly,this thesis summarizes the theoretical knowledge of container multimodal transport,such as the definition,constituent elements,container multimodal transport network,container multimodal transport path optimization and combs the main business procedures of container multimodal transport and the node transfer operation process of goods.Then,from the perspective of causes,this thesis analyzes the uncertain factors in the process of transport and the impact of these uncertain factors on cargo transportation,introduces the robust optimization theory used to deal with uncertain problems,and further discusses the connotation of transportation path robustness.In addition,the fixed departure time of trains and ships at the node of container multimodal transport and the mixed time window composed of node transfer operation time window and terminal receiving time window are described.The container multimodal transport path optimization model considering the above time constraints under the determined environment is constructed and a genetic algorithm is adopted based on the analysis of the characteristics of the model.Based on the path optimization model under the determined environment,considering the uncertainty of demand and transportation time between nodes,combined with the robust optimization theory based on scenario,two single factor uncertain multimodal transport path optimization models are constructed respectively.Considering the simultaneous uncertainty of transportation demand and transportation time between nodes,a multimodal transportation route optimization model is constructed,which takes the minimum sum of transportation cost and transit costs as the optimization objective and meets the constraints of mixed time window and transportation capacity,and an algorithm is designed to solve the route optimization model under the uncertain environment.Finally,through an example,the influence of different node operation time windows on the transportation scheme is explored,and the necessity of considering the node operation time window in the multimodal transport route optimization problem is verified.Then the multimodal transportation route scheme under the mixed uncertain environment of transportation time and demand is solved.Through the analysis of the example results,the effects of robust regret coefficient and the fluctuation range of uncertain factors on the result of robust optimization are discussed.This thesis focuses on the path optimization of multimodal transport under uncertain transportation environment,and adopts a gradual and in-depth research idea.Based on the introduction of theoretical knowledge of container multimodal transport,the combing of the container multimodal transport process,the analysis of the uncertain factors in the transport process,the fixed departure schedule of the transport mode and the mixed time window,a robust optimization model of multimodal transport path with mixed uncertainty of transport demand and transport time between nodes is established,and the genetic algorithm is designed to solve an example to verify the effectiveness of the model.The research results can provide reference for the follow-up research of container multimodal transport route optimization under uncertain environment.