Research On The Dynamic Evolution Of Urban Freight Network Topology Based On Logistics Node Attraction

As an important part of urban transportation,the urban freight network has been researched based on complex network theory.This article analysed the dynamic evolution and evolution mechanism of freight network.Meanwhile,the article reffered BA model and BBV model,and then constructed the freight transport network evolution model.The article made a deep analysis of the results,and offered some optimization methods of the model in order to provide theoretical basis for urban freight network planning and construction.At first,the article expounds the function of logistics node and the hierarchical division of the nodes.The logistics node attraction and the attraction degree were defined,and the Gravity Model of the logistics node has been constructed.Then,the article put forward major influencing factors of the logistics node attraction and the attraction degree,and the formulas of their solution were given.After introducing the Complex network theory and urban freight network theory,the article analysed the dynamic evolution of freight network,the growth mechanism and the preferential attachment mechanism of node.Meanwhile,the article made a deeper analysis to the urban freight network and contrasts to BA model and BBV model.It found out that they have something in common.Based on the evolution mechanisms,both of the BA model and BBV model,the article constructed the urban freight network topology with the logistics node attraction.In order to realize the visualization of the freight network dynamic evolution,the article used Matlab code to simulate the dynamic process both of the joining nodes and the emerging edges.With the help of GUI visual interface in Matlab,the freight network topology at different times can be presented.The results of the updating edge weights were exported into a CSV file simultaneously.Since the software for complex network analysis,Gephi,its visualization effect is much better than GUI visual interface.Besides,it has powerful function modules for calculating and analysing network topology attribute,not like Matlab which needs to input code to perform calculations and analysis.In the article,the results of the updating edge weights and the logistics nodes were exported into Gephi,so as to enable the visualization process transferred from GUI to Gephi.Then,with Gephi and ArcGIS docking,the freight network topology could be shown in form of geospatial network.Finally,after Completing the docking among GUI,Gephi and ArcGIS,the evolution results were analysed,and then the optimization ideas were proposed to improve the accuracy of the model.