Research On Network Vulnerability Of Urban Rail Transit System

With the improvement of modernization and the expansion of urban scale,the city depends more and more on the rail transit system,and its safety degree gradually affects the normal operation of urban functions.At the same time,the scale structure of urban rail transit system is gradually complicated in the continuous development and expansion,from the early single line simple structure to the network structure of inter line interaction.In the networked urban rail transit system,the relationship between stations,lines and between stations and lines is more closely.Once an emergency occurs in a station or a line,the highly interconnected urban rail transit network will expand its impact,so it is more sensitive.Then,the safety management of urban rail transit system also needs to meet the requirements,that is,gradually from independent single line to network direction.Based on the vulnerability theory,the complex network theory and the comprehensive application of statistics,management and other theories,this study systematically and completely analyzes the safety management of urban rail transit system.First of all,from the multi-level and multi-dimensional connotation of the concept of vulnerability,the concept of vulnerability,system vulnerability and urban rail transit system vulnerability are explained one by one,focusing on the research content of network vulnerability.According to the mechanism of network vulnerability,based on the theory of complex network,combined with the characteristic parameters of passenger flow,the three-level indicator system of network vulnerability is determined,including 3 secondary indicators and 10 tertiary indicators.At the same time,according to the twodimensional characteristics of network vulnerability,the evaluation and analysis are divided into two parts: node vulnerability and regional vulnerability.Secondly,the vulnerability evaluation model of urban rail transit system nodes is studied.In the process of evaluation,this paper not only considers the evaluation subject's preference for indicators,but also takes into account the data characteristics of actual application scenarios,so as to build a ?-ANP evaluation model to evaluate the vulnerability of nodes,so as to achieve the unity of subjective preference and objective reality,universality and special cases.Taking Beijing Subway as an example,the node vulnerability of 268 stations in the system is calculated,and the actual utility of the index weight obtained based on ?-ANP method is confirmed,and the advantages of the method and model used in this paper are verified.Thirdly,the evaluation model of regional vulnerability of urban rail transit system is studied.Based on the field theory,a regional vulnerability model with node vulnerability,topological distance and interval time as the core parameters is constructed.In this part,based on the distribution comparison of the regional vulnerability matrix(268 × 268)of Beijing Subway,it is verified that the regional expansion is based on the actual topology,that is,the actual geographical location is the main factor of regional vulnerability,but it can be modified and improved by the actual security management factors such as node vulnerability to meet the specific needs.At the same time,the whole Beijing subway network is divided into 19 vulnerable areas by using weighted Louvain algorithm based on the internal cluster characteristics of regional vulnerability.Finally,based on the two-dimensional characteristics of network vulnerability,this paper forms a crisscross complex but orderly management matrix.On the one hand,the vulnerability hierarchy of traditional security management is dynamically optimized according to the vulnerability of nodes;on the basis of retaining the current mainstream and relatively stable vertical hierarchical structure built by power organizations,the "one scenario,one scheme" is achieved,which is more adaptable to local conditions and has more practical value.On the other hand,based on the index characteristics of regional vulnerability,this paper proposes a Markov chain model for the classification of vulnerable areas,builds a horizontal action line,breaks the self-closed state between the links,and integrates the stations,organizations and individuals in each link of subway safety management.