Network Model And Research On Invulnerability For The Raiway Transportation System

Railway transportation system is the artery of national economy, bearing the most of thecountry’s passenger and cargo transport work, which is directly related with the rapiddevelopment of social economy and people life. Recently, railway transportation systemrepeatedly suffered damage from natural disasters, which brought great challenge to itsreliability. As the railway network scale expands unceasingly, its topology structure becomemore and more complex, so it is more important to study invulnerability for the raiwaytransportation system based on complex network theory. In order to solve the problem thathow to improve invulnerability for the raiway transportation network, by using transportnetwork self-characteristics, the knowledge of graph theory, probability theory, statisticalphysics, computer simulation, and other multi-disciplinary domain, this paper study someproblems, including the evaluation of station importance in the railway transport system basedon double networks and the invulnerability of the weighted railway network based on load–capacity model. More details and innovation are as follows:1).For the characteristic analyses of the previous models of railway network, this chapterestablishes three small networks which put Nanchang station as the center and repeatedlymake their adjacent matrixs. Then analyzes the evaluation of node importance measure, andpoints out their deficiencies. At last, we analyz the previous cascading failure models andinvulnerability for network measure, which proides theoretical basis for the analses ofinvulnerability for railway network.2).For the evaluation of station importance in transportation system of railway, firstly theweighted railway passenger bipartite network model is established according to the idea of thetransport capacity between the different traffic units and connection relation between thetraffic units and their stations. Based on previously mentioned network model, a resourceallocation algorithm is proposed and obtained the reciprocal distribution matrix of stationresource. Meanwhile, based on the network model the railway passenger transfer networkmodel is built, and the station efficiency is defined. Finally, evaluation matrix of the stationimportance in transportation system of railway is proposed based on taking into account thestation efficiency value, station degree and its adjacent station importance contributions whichuse the proportion of the total station resource and the station resource accounted which isassigned to the adjacent station to characterize the contribution of their importance, thealgorithm steps were shown in the whole process, the time complexity is O(m2n). The simulations verify the feasibility and effectiveness of the proposed evaluation matrix ofstation importance.3).Aiming at the invulnerability problem of railway network without consideringcascading failures and the previous cascading failure models are no longer applicable,invulnerability of the weighted railway network based on cascade failures is introduced. Inthis method, the traffic redistribution takes into account the neighbors’ surplus capacity andthe weights between the neighbors. Finally, we study the invulnerability of railway networkunder random network, small world network, scale-free network and interchange railwaynetwork. Some parameters are obtained when the railway network can reach the strongerrobustness level against cascading failures and acquire the critical cost minimization.