Research On Characteristic Analysis And Optimization Application Of Urban Transit Network Based On Complex Network Theory

As the city scale enlarges unceasingly with the rapid cluster expansion of urban agglomeration,motor vehicle population and road traffic volume increase steadily,motorization has brought huge social benefits to the development of urban economy,and it has also caused a series of traffic problems that restrict the sustainable development of cities such as the traffic jams,frequent accident and air pollution,has influenced the life quality of urban residents seriously.Intensive efficient and cheap convenient urban public transport is a fundamental way to improve the road space utilization efficiency and the urban transportation environment,priority to develop public transport as the government's strategic decision has become the consensus of domestic and foreign academic circles.Urban public transport system is an open and typical complex system,its organizational structure and evolution law are extremely complex,as the rise of complex network theory for studying complex system recently,provides a new method and perspective for the research of urban public transport system.This paper builds the models of transit station network and transit transfer network based on Gephi and Matlab software,and conducts the study of complex network theory for urban transit network in characteristic analysis,optimization and application three aspects.Firstly,according to different abstraction method of transit network models,this paper introduces relevant practical significance for complex network statistics indexes,with the case of Huangshi public transportation,builds the Huangshi transit station network and transit transfer network model,uses network data visualization software Gephi to analyze its complexity.Results show that:(1)Space L and Space P network degree distribution is nonlinear in the dual-logarithmic coordinates system,doesn't show obvious scale-free property;(2)Transit transfer network has a larger clustering coefficient and shorter average path length,shows the small-world effect;(3)Space L and Space P network centrality indexes are higher,and the number of interchange terminal in Huangshi public transport network is few and the function is not perfect.;(4)the betweenness and closeness index of network nodes are positively correlated.Secondly,to solve the problem that public transit trip chains of shortest path for the same node pair are not identical in space L and space P network,a network model shortest path optimization algorithm based on travel time impedance is proposed,and the concept of direct arrival distance matrix is introduced to implement the algorithm program on the Matlab platform.According to the actual survey data of the transit travel characteristics in Huangshi city,the parameter calibration of impedance weight in the target function is completed,and the validity of the optimization algorithm is verified through the network example.The result shows that the average path length of Huangshi transit station network and transit transfer network increased year-on-year index values by 16% and 34% respectively.Finally,this paper presents an application direction of complex network in urban public transportation,namely the identification of public transit transfer hub.Following the defining standard of shortest path length based on the path time impedance in the characteristic value network efficiency,select the change rate of network efficiency after simulating node failure as its evaluation index of important degree,design a transit transfer Hub location method based on network shortest path,so as to provide reference for the layout and construction of Hub station.Combined with the case of Huangshi transit network,the identification results and layout plan of huangshi city were found,by comparing the identification result with the layout planning find that this method has a high identification for the pivotal position of traffic in Huangshi,which is located in the urban geographical center.