Research On Key Node Identification And Robustness Optimization Of The China Railway Express Transportation Network

As an important carrier of the Belt and Road Initiative and a name card of China Railway’s “going global” initiative,the China Railway Express shoulder the responsibility of promoting infrastructure connectivity and unimpeded trade among countries along the route.Since the first China Railway Express train started operation in 2011,the cities and routes of the China Railway Express have increased year by year,and the scale of the transportation network has continued to increase,showing the nature of a complex network.At the same time,the China Railway Express trains pass through many countries in Asia and Europe.There are big differences between different countries and regions in macro policies and route conditions.Once some important nodes in the network fail or lines are interrupted due to force majeure or other factors,it will affect the normal operation of the China Railway Express.Therefore,based on the complex network theory,this thesis conducts research on the topological properties,key node identification and robustness optimization of the China Railway Express transportation network,aiming to optimize the layout and improve the transportation service level and anti-risk capacity of the China Railway Express transportation network.The main research work of this thesis is as follows:This thesis reviews the relevant research and related theories of the China Railway Express transportation network,and clarifies the research ideas.According to the structural characteristics of the China Railway Express transportation network,the basic road network and train flow network of the China Railway Express are constructed based on the complex network theory,and their topological characteristics are analyzed.The results show that there are differences in the scale-free and small-world characteristics of the basic road network and train flow network of the China Railway Express.Aiming at the identification of key nodes in China Railway Express transportation network,this thesis proposes a key node identification method for multi-layer networks combining the improved technique for order preference by similarity to an ideal solution and grey relational analysis.After comprehensively considering and selecting a variety of node importance evaluation indexes,the improved technique for order preference by similarity to an ideal solution is used to calculate the weight of each index and the importance of nodes in single network layer,Then,the importance of nodes is fused by grey relational analysis,and the importance of nodes in China Railway Express transportation network is comprehensively evaluated;The accuracy of the proposed method is tested by using the multi-layer network propagation dynamics model,and based on the identification results,the robustness optimization suggestions of China Railway Express transportation network are put forward from the point of nodes.The results show that the key node identification method proposed in this thesis has better applicability to China Railway Express transportation network.Aiming at the robustness optimization problem of the China Railway Express transportation network,this thesis puts forward the robustness optimization model from the perspective of the basic road network and train flow network,and designs the discrete binary particle swarm optimization algorithm combined with complex network theory and the link prediction algorithm based on structural similarity for optimization respectively;The optimization results are obtained through case analysis,the basic road network and train flow network of the China Railway Express before and after optimization are attacked to verify the results.The results can provide a reference for the construction of new channels and the operation of new routes in China Railway Express transportation network.