| Urban road network is a typical complex network composed of a large number of nodes and edges.As the lifeline of the whole city,which plays an important role in people’s life and production,has become the material foundation of human survival and development.However,due to the wide distribution of urban road network,it is very vulnerable to the destruction of natural disasters such as bad weather,geological disasters and other accidents such as traffic accidents,large-scale activities and road maintenance,resulting in the decline of road network capacity,serious will lead to a large area of the entire network congestion or even cause road network paralysis.It is found that the failure of urban road network traffic function is often caused by congestion or interruption of some key nodes or sections.It can be seen that some nodes and sections of the road network play an important role in the safety and reliability of the whole road network.It can be seen that identifying the key nodes and key sections of the urban road network can not only provide important decision support for the traffic management when dealing with traffic management,traffic control,road network reconstruction and emergency rescue and evacuation in urban road network.But also can provide some guidance for the correct choice of residents’ travel program,reduce the residents travel time and travel costs of the loss.Based on the above analysis,this paper uses the basic theory of complex network and traffic flow to identify the key nodes and sections of urban road network,the specific research contents are as follows:This paper first gives the definition of the key node of city road network.The evaluation index of the node is introduced from the aspects of complex network characteristics and traffic flow characteristics.Then,according to the characteristics of the transportation network,the concept of urban road network node degree and the node space kernel based on the improvement degree are defined.Finally,considering the network structure characteristics,spatial location attributes and traffic characteristics of nodes in the road network,four indexes of node degree,kernel degree,traffic proportion and saturation are taken as the evaluation indexes of key nodes in urban road network.On this basis,the recognition model of key nodes is constructed,and the basic idea and realization process of the algorithm are given.Secondly,the definition of the key link is given from the point of view of vulnerability.According to the definition,in the study of the failure probability of the road section,from the point of view of risk probability theory,a Bayesian network model based on the minimal path set is constructed.On the basis of the construction of the failure consequence model,the influence of the network traffic distribution and network topology structure is considered.The model is defined as the weighted sum of the change rate of the network efficiency and the total travel time,which effectively avoids the limitation of the previous study that only a single index is used to evaluate the failure consequence of road sections.On this basis,the identification model of the key sections is constructed,which can be used to determine the key sections of the road network by comparing the key dimensions of each section.Finally,this paper takes Xi’an city in a regional road network as an example.Through the traffic survey to get the regional road network conditions,traffic and other basic information.The key nodes and the road sections of the regional road network are identified by using the identification model of the key nodes and key sections proposed in this paper,which proves that the proposed model has certain theoretical and practical significance. |
