Robustness Analysis And Optimization Of Air Rail Intermodal Composite Network Based On Complex Networks

The high-speed passenger transportation network composed of civil aviation and high-speed rail is the main force driving the country’s socio-economic development,and both are indispensable.Driven by China’s "transportation powerhouse",China’s high-speed railways have formed a "four vertical and four horizontal" layout,with short distance passenger transportation as the main focus.According to the requirements of the "National Comprehensive Three-dimensional Transportation Network Planning Outline",China’s high-speed railways will develop in the direction of "eight vertical and eight horizontal",becoming more dense and hierarchical.With the increase in the number of airports and the reasonable allocation of airspace resources,the network structure of civil aviation is becoming increasingly tight,and it has huge advantages in the medium to long distance and ultra long distance markets.However,the rapid development of the high-speed railway network has put enormous pressure on the passenger transport market of the civil aviation network,which has made the conflict between the two more acute,and the air rail composite network may become a way to solve this conflict.What is even more thought-provoking is that with the epidemic and changes in the international situation,civil aviation and high-speed railways will have a certain impact on the operation of regional transportation hubs in the face of emergency situations.The weakness of the air rail composite network in resisting external risks is also more obvious.Therefore,this article intends to use the method of "network edge augmentation" to optimize it,in order to improve its robustness under unexpected events such as randomness and deliberate behavior.The research content and findings of this article are as follows:(1)The structural characteristics of aviation network,high-speed railway network,and air rail composite network were analyzed.This article intends to build a complex network model based on P-space through the study of multiple networks such as aviation network,high-speed rail network,and air rail network on the basis of existing research,and use P-space methods to model it.We found that multiple networks,including aviation,high-speed rail,and air rail,exhibit scale-free,small world network characteristics,indicating that the network system has structured features and can be subjected to robustness analysis.(2)Research on the robustness of the three major transportation networks: aviation,high-speed rail,and air rail.The robustness of complex networks is reflected in their resilience and fragility.This project will design simulation attack algorithms for random attack strategies and intentional attack strategies based on network connectivity,network efficiency,relative size of the largest connected subgraph,and natural connectivity of the network.The constructed complex network models will be simulated for attacks,and the intentional attack strategies will be ranked according to degree,medium,and kernel to obtain the robustness measurement results of the complex network.Through the measurement results of network robustness,it was found that under the random simulation attack strategy,the network showed resilience,and the proportion of nodes removed increased,resulting in a decrease in network stability;In the deliberate simulation attack strategy,in the degree ranking and intermediate ranking simulation attack mode,a small proportion of node removal reduces the robustness of the network,and the network shows vulnerability.Optimization of network robustness based on network robustness and community structure.The air rail composite network in China has obvious hierarchical structure characteristics,and the construction goal of China’s transportation network is to "highlight hubs and connect levels".Therefore,this article intends to use the Louvain algorithm,with the basic idea of adding edges to the internal network of the community,to study the air iron composite network.In response to the problems in the air iron composite network,the network edge adding method is adopted to increase the internal connections of the community,achieving robustness optimization of the air iron composite network.By combining the nodes of the air iron composite network,we can divide it into 5 community structures,thereby improving the robustness of the air iron composite network to a certain extent.