Modeling And Simulation Of Public Transit Network Survivability Based On Complex Network Theory

The best strategy to alleviate urban traffic congestion is to give priority to the development of urban public transit system. Currently, the researches on urban public transit system mostly focus on the reasonable planning of line network and operation optimization management, but less attention has been paid to the survivability of urban public transit network under the influences of traffic congestion, terrorist attacks and other emergencies. This work takes urban public transit network as the research object based on complex network theory. From the aspects of public transit network abstract modeling, survivability model construction and case simulation study, this work gives the general methods, algorithms and simulation programs of public transit network survivability under different perspectives; and gets the complex dynamic evolution mechanism of public transit network survivability, which provides the guidance for operation management and transformation design of public transit network, and has certain theoretical significance and application value.The main works are as follows:(1) Related researches on complexity and survivability of public transit network, survivability of multiple layered network are summarized and combed. Additionally, the complex network basic theory, such as graph theory basis, main topology parameters, traditional survivability measurement indicator and typical topology structure are also introduced.(2) Static survivability of public transit network. This work constructs public transit geospatial network based on space L method, and by comparing with the statistical properties of traditional survivability measurement indicator, a new method that to measure the static survivability of public transit network based on network structure entropy is proposed. Finally, case study gives the complexity and survivability of Jinan city's public transit geospatial network, and verifies the correctness of network structure entropy based on betweenness importance which is taken as new survivability measurement method.(3) Dynamic survivability of weighted public transit network. In order to construct weighted public transit network, this work introduces bus routes density and departure frequency relative value to modify the traditional space L method. Then, by modifying the load-capacity model of cascading failures, the dynamic survivability model of weighted public transit network under single station deliberate attacks is constructed. Finally, taking Jinan city's weighted public transit network as example, its dynamics simulation analysis of dynamic survivability is given.(4) Dynamic survivability of double layered public transit network. This work takes public transit geospatial network as the lower layered network of double layered public transit network based on space L method, and takes weighted public transit network as the upper layered network of double layered public transit network based on modified space L method; introduces the influences of adjacent stations on definition of station initial load, connected edge transit capacity, coupled capacity and the coupled effects between lower layered and upper layered public transit network to modify dynamic survivability model of weighted public transit network; and constructs the dynamic survivability coupled model of double layered public transit network with "interdependent relationship". Finally, taking Jinan city's double layered public transit network as example, its dynamics simulation analysis of dynamic survivability is given.