Research On Dynamic Freight Optimization Of Multi-modal And Multi-route In Transportation Network

In recent years,the construction of highway and railway networks has been vigorously arranged throughout the country,greatly increasing the connectivity of highway and railway networks among cities.From a freight point of view,these networks form a large transport network.In the transportation network,freight service providers need to meet the transportation needs generated in different periods and regions,but the traditional transportation organization form is difficult to meet the needs of customer diversity.At the same time,the freight market competition is fierce,freight service providers to not be eliminated,need to take advanced transportation management methods to reduce transport costs.In order to better meet the demand of freight market,this paper considers the temporal and spatial characteristics of freight transportation and the uncertainty factors in the transportation process,and uses the knowledge of fuzzy mathematics and operational research to study the multimodal and multi-route dynamic freight optimization problem in the transportation network from the perspective of freight service providers.According to the existing freight information,the modal parameters are set and the modal is solved.Finally,the relatively optimal transportation route,transportation modal and delivery time of the goods are obtained,so as to reduce transportation costs and improve the quality of transportation services.This paper studies the multi-route dynamic freight optimization problem of multiple modes of transportation in the transportation network,constructs a mixed integer programming model for the problem,and designs a heuristic algorithm based on the greedy criterion to solve the model.The algorithm can effectively improve the solution time of the model when solving the example.Finally,the optimal transportation scheme is obtained by solving the actual case.The main work of this paper is as follows:(1)The multi-modal and multi-route dynamic freight optimization problem in the transportation network under certain conditions is studied.This paper comprehensively analyzes the influencing factors of transportation modal and route selection in transportation network,puts forward the concept of freight scheduling set,and establishes a multi-modal and multi-route dynamic freight mixed integer programming model in transportation network under certain conditions to solve the problems of transportation modal selection,delivery time,transportation route and freight flow splitting.According to the characteristics of the model,a heuristic algorithm based on greedy criterion is designed.The model and algorithm are tested by small-scale network examples,and the approximate optimal solution and accurate solution are compared and analyzed to verify the effectiveness of the proposed algorithm.(2)The multi-modal and multi-route dynamic freight optimization problem in transportation network under uncertain conditions is studied.Combined with the actual transportation situation,the uncertainty in the transportation process is comprehensively analyzed,and the uncertainty factors are regarded as fuzzy parameters.A fuzzy mixed integer programming model for multimodal multi-route dynamic freight transportation in transportation network under uncertainty is established.Fuzzy programming theory is applied to transform the objective function and constraint of the model,and a heuristic algorithm based on greedy criterion is designed.Finally,a practical case is given to verify the rationality of the model and the effectiveness of the algorithm.