Analysis Of Urban Rail Transit Network Evolution Based On Complex Network Theory

Urban rail transit has made great contributions to alleviating urban congestion.At present,since most cities in my country are vigorously constructing rail transit projects,the understanding of urban rail transit is not complete enough.The analysis of the evolution of the rail transit network helps us understand the internal mechanism and operation rules of the network evolution,and it can also reveal the complexity of time and space from a macro perspective.In addition,the scientific and objective identification of important stations in the rail transit network can provide a certain degree of scientific basis for the adaptive planning of the relationship between the station and the city layout,the protection of important stations in emergencies,and the integrated development around the important stations.Firstly,this thesis introduces the basic knowledge of complex network theory and analyzes the factors that affect the evolution of the rail transit network topology.Then use this theory to abstract the rail transit network into a complex network,and select indicators such as average path length,clustering coefficient,average adjacent node degree,and network efficiency.The comparative analysis of the changes in the indicators of the rail transit networks in the five cities of Beijing,Xi’an,Nanjing,Chengdu,and Shenzhen during their respective evolutions.It is concluded that although there are large differences in the scale of the rail transit networks in the five cities,the change trend of the complex network metrics is generally consistent.Secondly,the node importance degree theory is introduced,and the three indicators of node degree,intermediary and closeness are selected to comparatively study the changes of key stations during the annual evolution of the rail transit network in Beijing,Nanjing,Xi’an,Chengdu and Shenzhen.The key stations obtained by using different indicators are not the same.At the initial stage of the development of the line network,most of the key stations have higher degrees and are located in the center of the city.As the line network expanded outwards,key stations were changed to stations in the outer city areas.In addition,some of the stations close to the transfer station are also key stations,so this type of station should also be paid attention to during operation and management.The identification of key stations of the track network can plan and manage the stations in a more targeted manner.Finally,the passenger flow factor is introduced,and the weighted network model of rail transit passenger flow is established based on the data of each stage of Xi’an rail transit network.Contrast and analyze the changes of unweighted node degree and node strength,unweighted shortest average distance and weighted average distance,unweighted average tightness and weighted tightness,The conclusion of the corresponding rail transit network evolution is drawn,which provides a theoretical basis for the subsequent development of urban rail transit.