Study On Cascade Failure Model And Mitigation Method Of Urban Road Traffic Network

In recent years,with the development of economy,the congestion problem of transportation network also arises immediately.Among them,the cascade failure phenomenon on the traffic network is more destructive and has a wider impact,and has exacerbated the waste of time and resources.Therefore,more and more attention has been paid to the cascade failure of urban traffic network and its mitigation strategy.This paper addresses the above problems to study the effective methods and approaches of alleviating traffic congestion from the perspective of complex network.The specific research contents are as follows:Firstly,for the problem of cascade failure modeling,we defiened the average distance and the state change time.Using the weighted algorithm to combine the two factors,a trust value model is got to measure the traffic congestion.Then in order to avoid the congestion of the failure node again in a short time,the redundant load of the failed node is redistributed according to the proportion of the trust value.Finally,the cascade failure model is obtained.The simulation results show that the joint parameters can control the cascade failure scale in a certain range,which improves the robustness of the network.Secondly,we studied the congestion alleviation problem of single intersection in network.The inflow/outflow of intersections is defined,and the strategy of road closure is introduced.When the road inflow of the congestion intersection is from all closed to open gradually,the congestion mitigation time is obtained.The simulation results show that the relationship between the opening number of closed roads and congestion mitigation time is consistent with the theoretical analysis.The larger the number of roads connected to the failed intersection,the longer the congestion mitigation time.In order to ensure that the intersection can alleviate the congestion quickly,the opening number of closed roads should be less than or equal to half of the total number of roads.Finally,we extended the congestion mitigation strategy of single intersection,and obtained a cascade failure mitigation strategy based on edge control mode.We introduced the transmission rate coefficient and transfer volume of the edge,and built the redistribution rules of the load.By controlling the transmissioin rate coefficient,we proposed the cascade failure mitigation strategy.Based on the example verification,our findings indicate that the proposed congestion mitigation strategy can control the cascade failure scale in a certain range.Meanwhile,it can repair the failed nodes to ensure the network back to its normal operation.Compared with the other congestion mitigation methods,our mitigation strategy has a smaller cascade failure scale.