Invulnerability Of Urban Water Supply Networks Based On Node Importance

With the rapid development of urbanization in China,the scale of cities and towns is showing explosive growth.With the increasing size of the city,the layout of water supply system is more disorder.The reliability of urban water supply system is the core support of urban development.However,with the increase of urban population,the scale of urban construction and the frequent destruction of the outside world,the destruction of urban water supply system is more diverse and more powerful,which will seriously affect the robustness of the water supply system.At the same time,node as an important component of urban water supply network,its own characteristics have an important impact on the invulnerability of water supply system.Therefore,based on the degree of node importance,it is an important aspect of improving the reliability of the urban water supply system to study the destruction resistance of the urban water supply network and improve the resistance of the water supply system to the disaster.This paper comprehensively uses the theory of Graph Theory,Complex Network and Information Entropy to put forward the measure and optimization invulnerability model of the urban water supply system,from the perspective of the nodes of the water supply network.First,the elements of the water supply network are made,and then urban water supply system is expressed abstractly,the mechanism of the node influence to the city invulnerability is analyzed.The node importance is calculated from two aspects of node function and the node structure,and then the solution process of this model is put forward.Secondly,defining probability space with node importance,the model of the destruction entropy is built by the information entropy theory to measure the degree of the node importance equilibrium,and the condition of the extreme resistance of water supply system is excavated.Based on the results above,the method of calculating the invulnerability of water supply network is put forward.Then,considering the two objectives of cost minimum and invulnerability maximum,with the constraint conditions are pipe location,pipeline path and pipe diameter,a invulnerability optimization model is established.Based on the minimum tree graph method,the topology framework of water supply network is determined.Through successive edge increasing method,the optimal topology of water supply network is determined.Through the adjustment of the pipe diameter,the optimal pipe diameter is determined,and the aim of optimizing the resistance is to be optimized.Finally,take a specific engineering as a cases,the importance of nodes is determined,and the invulnerability of water supply network is evaluated,and the topology of pipe network is optimized to improve the invulnerability of the system.The invulnerability measurement method and optimization method proposed in this paper provide theoretical support for urban water supply safety management,and also provide guidance for urban water supply system planning.