Study Of The Vulnerability And Optimal Designing Of Lifeline System Based On Complex Networks

Lifeline systems, including water supply system, power grid, andtransportation system etc., are serving greatly as supporting societydevelopment and people wealth. While playing an honorable role, thesystems are suffering from two main problems. First, due to the huge sizeand great complexity itself a small mistake would cause a severe disaster,no mention to the nature disaster and terrorists. Second, with the big sizeof the modern society, the cost of lifeline systems is skyrocketing. So theresearch on the optimal designing of the lifeline systems based on theabove two issues is of great importance.First, this thesis analyzed the scenario of the cascading effects oflifeline systems in detail as well as the model of the cost calculation basedon complex networks theory. A model based on traffic jam and recoverywas used, which simulated the cascading effects of the lifeline systems in amore detailed way. An expression based on the shortest path of complexnetwork was used to calculate the cost of construction. A heuristic methodwas designed to evolve the initial random networks to reach the networkswith optimal cascading vulnerability and construction cost.Second, based on the motif of complex networks, this paper analyzedthe evolution of relative ratio of four node motifs in the evolution process.The relative ratio of four node motifs stayed stable when the networksreached the optimal structure was observed. This would serve as atheoretical paradigm for designing and developing the lifeline systems.Data from American power grid was used the verify proposed model andalgorithm. The comparison showed hardly a difference between the tworesults. An analysis method for inspection into the micro structure of the networks was also proposed. The results stated that it would provide anovel perspective and tool for the analysis of the networks structure.