Study On Dynamics Of Cascading Failure And Important Evaluation Of Section Road On Complex Road Networks

Accompanied by the development of the economy, the sharp increase of the automobile amount has led urban road network to be more and more complicate that ultimately appears on a look of complex giant system. Phenomenons such as low traffic speed, traffic jams and even traffic paralysis in large area on urban road networks are also problems needs to be solved on modern city traffic networks. To solve such problems essentially, further advanced and effective research method needs to combine complex network theory, graph theory and GIS technology from two aspects such as the network structure and network function of urban traffic network. It has become the research hot point problem in the field of traffic congestion mitigation. The complexity of the structural research includes road network modeling, topology structure study and etc. Function research based on structure includes dynamic traffic assignment, road network reliability research, cascade dynamics research and etc. As the inherent exploration of network structure and function complexities inner influence on the forming of traffic jams, this dissertation firstly studied the urban road network topology complexity, constructed community structure road network from urban road network featrues and verified statistical characteristics on it; then studied from cascading dynamics on topology structure to revel inner factors of traffic jams; finally studied section node importance evaluation method and provided scientific decision reference for transportation planning and design. In particular, the research work and achievements of this dissertation are as follows:1. Studing the fractal characteristics results on each big city urban road network. These fractal characteristics results demonstrated that the regional distribution characteristic of city urban road complex network shows a decreasing trend on distribution coverage and connectivity from the measuring point to start. This research result is consistent to the module structure characteristics of the complex network, as a result, this dissertation used a segmentation method based on administrative regions, in the public critical point of region to region used self defined cohesive function to constract community structure of road network. The methord was adopted on the community sctructure of road network construction of Chengdu city road network, and the stastical feature of complex network community structure of roadnetwork was verified on it. The results show that the network community structure partition algorithm of this dissertation is reasonable and effective.2. Citing the gravitational field dynamic traffic assignment method based on complex network routing, distributing dynamic flow for dual structure road network. The load-capacity model of gravitational field of complex network cascade effect routing strategy was proposed. Two evaluation indexes such as average pathlength ratio and the network scale were introduced. The experimental results show that the gravitational field of the cascade complex network routing failure model was obvious more effective on two indicators such as average pathlength ratio and network scale than the shortest routing flow cascade effect model.3. Defining the m order of neighbor nodes concept. Considering the interaction between the sections of the nodes of the network is not only related to the adjacent nodes but also related to other nodes in the network. This relationship was used to evaluate the complex network nodes importance and to define the evaluation model of single and multi factor. Results of evaluation methords based on degree, betweenness and etc. were comparised on BA network and Chengdu city road network. Experimental results show that this evaluation method can improve the precision and accuracy assessment.4. Proposing the complex road network road section importance evaluation methord based on the theory of field. Taking reference to m-order adjacent node concept and road section node gravitational field concept, evaluation function of gravitational field road section importance was proposed. The evaluation function of alpha, beta two parameters dynamically adjusted the gravitational field on the same gravitational field value node. Finally, the evaluation model was verified on Chengdu city road network, results showed that the evaluation model can improve the precision and reliability on road section importance.