Research On Complex Network For Smart City Cyber-physical System

With the continuous evolution of smart city cyber physical system and ICT,enormous complex networks are established,which go deep into people's daily life.Nowadays,people's requirements for network quality are increasely strict.Therefore,the research on network communication dynamics and congestion has gradually attracted scholars' interests.As complex network theory's rapidly development,using complex network to character complex systems in realistic life become possible,which can be used to study the propagation dynamics of smart city information system and improve the network quality.In fact,many empirical studies show that the quality of network has two basic influence factors: characteristics of the infrastructure and routing algorithm.In view of this,it's worthy to generate better routing stratege in smart city cyber physical system.Based on the complex modle,the thesis mainly studies the routing strategy of smart city cyber physical system to optimize the network transmission capacity.The thesis purposefully analyzes the influence of network structure on the global efficiency and average connectivity when using traditional shortes path routing stratege(SP).And decide to make betweenness centrality as the measurement index of the importance of nodes in the network.Through the analysis of the smart city cyber physical system,the thesis establishes a complex network model.Also,conbined with the data traffic model,the thesis discusses the complex network characteristics & important nodes' impact on network capacity.Then goes deep in the mechanism of network congestion and network performance degradation.At last,it is concluded that the failure of important nodes will significantly cut the network efficiency and average connectivity,and the network transmission capacity is related to the maximum effective betweenness centrality of nodes.To ease the fatal problem of congestion and uneven load distribution of important nodes in SP routing strategies,thesis proposes a global routing stratege which based on betweenness centrality of nodes(BR).By analysing the attractive force of nodes to data flow in the transmission process,thesis establishes a gravitational force field model by considering betweenness centrality and idle rate of nodes,and proposes a routing strategy based on the gravitational force field model(FR).As the simulation comes out,BR and FR effectively balance the load among nodes and improve the network transmission capacity.Compared with SP algorithm,BR and FR effectively increase the network transmission capacity by 4.4 times and 5.4 times.