Study On Analysis And Optimization Of Ningbo Public Transportation Network Based On Complex Network

The urban public transportation system is a public welfare transportation enterprise built to meet the daily travel needs of residents,and it is also a functional infrastructure that supports the operation of the city.Public transportation planning is one of the most important urban transportation special plans.How to avoid competition between conventional public transportation and rail transit,strengthen transfer connections,and improve the reliability of the public transportation system are problems that Ningbo City faces in the priority development of public transportation.The urban public transportation system is proved to be a typical network structure because of its element composition and operational characteristics.In this thesis,the public transportation system composed of conventional public transportation and urban rail transit is regarded as the main research object.The stations in the public transportation network and the adjacency between different stations are abstracted as important elements of the network model.By designing different semantic models,the actual public transportation network is abstracted into a complex public transportation network model.The complex realistic problems are transformed into simple mathematical models,and then the public transportation network in Ningbo is analyzed and optimization strategies are proposed.Firstly,three models of L-space,R-space and P-space are used to construct ideas,and the complex network of public transportation under different semantic models is constructed respectively according to the crawled operation data.Secondly,the structural characteristics of three types of public transportation complex network models are described and analyzed by calculating static characteristic parameters.The station network and transfer network are proved to show significant scale-free characteristics,and the line network is proved to belong to the small-world network model.Then the robustness of network is measured by designing different types of attack methods and algorithms,the conclusion is derived that the station network is vulnerable after the intentional attack of node degree reduction sequence,while the line network is less sensitive after the attacks,and the network topology is relatively stable.On the basis of static structure analysis and dynamic performance research,improving the network topology and the robustness are regarded as the optimization goals.The area optimization plan is proposed according to different types of methods by identifying the optimized object.The effect of the optimization plan is evaluated by the robustness index change.It is confirmed that the connectivity performance of the optimized station network and line network has improved.