Research On Importance Evaluation Of Node And Cascading Failure Invulnerability Of Urban Rail Transit Network

With the accelerated process of urbanization,the major cities have the upsurge of urban rail transit construction.Beijing,Shanghai,Guangzhou,Shenzhen and other large cities have formed urban rail transit network,and with development,increasing urban rail transit network will enter the network operation stage.As an important part of urban transport system,urban rail transit carries a large number of transport tasks.Once the network equipment failure,it will seriously affect the network function.So in the network operating conditions,it is the premise of security operation security,emergency resource allocation and network structure optimization to clear rail transit failure of the network degree and impact range.Firstly,This paper,based on the complex network theory,clears the definition of urban rail transit network and selects the Space L method to construct the model of urban rail transit network by comparing three network modeling method.Next,evaluates the node importance of the urban rail transit network from the local and global properties of all nodes and the function of the node connected.It establishes the evaluation system of node importance from three aspects.Then combining with TOPSIS(Technique for Order Preference by Similarity to an Ideal Solution)method to determine the rank of the node importance,and based on the node importance using K-means algorithm to cluster partition.The second,combining with characteristics of urban rail transit,it constructs cascading failure model in the urban rail transit network.In the model,the method of traffic flow allocation and related variables are determined.In addition,traffic reallocation method under node failure is determined,and according to the cascade failure process,it put forward the simulation process and algorithm.Then it analyzes the influence factors of cascading failure invulnerability and puts forward the evaluation index based on the definition of the cascading failure invulnerability.Finally,selecting Beijing rail transit network as case study in this paper,it analyzes the features of Beijing rail transit network and evaluates the importance of the nodes.Next,it simulates cascading failure process,according to the cascading failure model.In addition,it analyzes the network cascade failure invulnerability ability of the Beijing rail transit network in case of node failure,finally it synthesis of node importance of the hierarchy by comprehensively considering the node importance of the static and dynamic,and then it puts forward the corresponding optimization suggestions on the basis of the above research.