Research On Robustness Of Urban Rail Transit Weighted Networks

Urban rail transit is to resolve the traffic congestion and the important infrastructure of auxiliary traveler complete travel purpose,with the expanding of city scale,urban rail transit development is rapid,the role of more and more prominent.Into network operation area,the number of rail transit transport travelers have more than ordinary ground traffic,other areas also presents the trend.In order to minimize operational incidents in urban rail transit or malicious damage the effects on the traveler,to enhance the stability of system and strain capacity,it is necessary from theory height for urban rail transit topology and robustness analysis.Based on complex network theory and graph theory,the urban rail transit system building as the weighted network,mainly considering the network is attacked the impact on the traffic.More important in urban rail transit network is studied four issues,including measurement of the link weights,the transportation bottleneck identification,the collapse of the cascading failures and network,established a description model and the algorithm for solving the above problems,gives a quantitative indicators of evaluation.The topology of the network research mainly through the network,the basic measure of including degree and degree distribution,average shortest distance and the shortest distance,clustering coefficient and network efficiency and betweenness.In order to quantify the robust performance of the network,set up four evaluation indexes,including connectivity,maximum relative size of connected subgraph,network efficiency and travel to rate,the rate of travel to pay more attention to consider the function of the network,is based on traffic weight when depicting an important index of network function.In order to more detailed studies network topology and robustness,this paper designed the six attack experiment,including random attack is four,select two attack scenarios.Start with a small number of sites for 9 network to the established model and algorithm are verified,and on the basis of the algorithm is proved to be correct for a number of sites for 288 large real networks are simulated and the simulation was calculated under different experimental scheme of topological parameters and robustness index.Using mathematical software Matlab for computing tools,topological parameters and robustness index for the programming calculation,the degree distribution of the initial condition of urban rail transit network degrees obey the power law distribution,embodies the scale-free feature of network,against random attacks on experiments also show that the network has strong robustness;indeedTopological parameters calculation network with small world properties,does not have high clustering;The calculation results show that the efficiency of network connectivity of the network is low.Random attack a single node and single sections of road network is very small,the influence of network to provide alternative routes of ability;Setting failure value,random continuous attack nodes and sections,networks are still show the strong robustness;Select a node attack,including the node degrees of maximum weight,node and point betweenness maximum,clustering coefficient,maximum node,network efficiency and travel to rate are affected by smaller,relatively,attacking the largest node betweenness,network efficiency decreases rapidly;Choose to attack a stretch,including weight and maximum edge betweenness of the largest sections,network robustness is serious;The nodes and edges in descending order different measure,in order to attack found continuity,attack node selection,system showed significant vulnerability,and choose to attack edge system has stronger robustness,still one of the biggest choice against betweenness point to the destroyed most of the network.Through the contrast analysis shows that urban rail transit network show different properties under different attack strategy,choose under network is vulnerable,random network has strong robustness under attack.Research by the theoretical model and the algorithm is designed to predict any attack may cause cascading failures as well as the various sections of the change of flow,by reducing the response time in case of emergency situations and protection to improve the robustness of the system in advance.