The Lgyout Optimazation Of Freeway Emergency Resources Stations Based On The Node Centrality

Freeway network operation characteristics are becoming more and more prominent.For hub nodes which play a key role in the road network,if emergencies are not handled in time,it will cause a large area of long-term congestion around the road network.Improving the emergency support of these key nodes will help to improve the overall emergency level of the road network.At present,there are many problems in Freeway Emergency Resource reserve,such as diversified management subjects,decentralized reserve relying on territorial areas,unclear emergency rescue functions of materials,which affect the efficiency of emergency network response.Therefore,it is of great significance to set up emergency resource depots of freeway with reasonable layout and complete functions to promote the level of freeway emergency management.Based on complex network,this paper identifies the key nodes in the road network and studies the layout optimization of emergency resource points of freeway by analyzing the road network topology and node centrality,Firstly,it analyses the existing problems of freeway emergency management mode,puts forward the centralized reserve mode of emergency materials based on the joint management of highway police,and defines the functions of the points.Secondly,based on complex network theory,the basic structure of Freeway topology network,mileage-weighted topology network and traffic-weighted topology network are constructed.Eight indicators are selected from four aspects: degree centrality,betweenness centrality,closeness centrality and network efficiency centrality.A comprehensive evaluation model of node centrality based on Entropy Weight—TOPSIS is constructed and solved by MATLAB.The price result is used as the weight of accident points in the location model.Thirdly,constructing the multi-level point layout system by considering the rationalization of the functional structure of resource points.For the functions and radiation ranges of all points are different.The demand grading evaluation of emergency materials is carried out by using system clustering,and the material allocation strategy of points is put forward.Finally,based on Set Covering Model,the upper goal is to set the minimum number;based on P-median and excess coverage model,and with overall timeliness and multiple coverage as the lower objectives,a two-tier multi-objective resource point location optimization model is constructed,which is conducive to Lingo software programming to achieve the solution of the model.Taking the freeway network of Wuhan City Circle as an example to evaluate the centrality of 154 nodes,whose results show that there are many key nodes in it.Taking the construction of two-level emergency resource points of "Emergency Resource Station-Emergency Resource Center" as an example,the location of 18 emergency resource stations and 6 emergency resource centers was obtained.The results show that the optimal layout scheme improves the emergency timeliness and coverage times of key nodes in the road network,and verifies the feasibility of the model.Comparing the number of different points been set,it is found that the more the number of resource points,the higher the emergency efficiency.Increasing 1 to 2 points is obviously improvement.This paper provides a new idea for the location of emergency resource points,and the research results have certain guiding significance for the layout of emergency resource points of Freeway in Wuhan city circle.