Robustness Enhancement Strategies Of Complex Networks With Adjustable Weight Under Cascading Failures

In case of failure or malicious attack,complex network systems such as power network,communication network and transportation network in the real world need to have strong enough robustness to ensure the normal operation of the system,reduce the risk of cascading failures of the network system and ensure people’s life efficiency and quality.In this thesis,the robustness enhancement strategies of weighted adjustable complex networks with edge failure,node failure and dynamic load change are studied respectively.The main research contents and innovations are as follows:(1)For the problem of the cascading failures caused by edge failure in complex networks with adjustable edge weight,a selective edging robustness enhancement strategy based on the minimum neighbor edge capacity threshold is proposed.Based on the characteristics that the edge load in the network comes from the node load,a model for cascading failures of complex network with adjustable edge weight is constructed,and the robustness evaluation index of complex network against global collapse is proposed.After the failure of network edge,based on the minimum threshold criterion of neighbor edge capacity,selective edge addition is carried out from one end of the failed edge.Simulation results show that the edging strategy can effectively reduce the risk of global collapse of the network and enhance the robustness of complex networks under cascading failures.(2)For the problem of the cascading failure caused by node failure in complex networks with adjustable node weight,a robustness enhancement strategy of node weight parameter adjustment based on the minimum node critical capacity threshold is proposed.Considering that adjusting node weight parameters can change the characteristics of load redistribution mode in the network,a model for cascading failures of complex network with adjustable node weight parameters is constructed.This thesis reveals the relationship between node weight parameters and network robustness under cascading failures,obtains the optimal weight parameters when the complex network has the minimum node critical capacity threshold,and adjusts the weight parameters of the complex network.Simulation results show that this strategy can effectively reduce the node failure scale of the network under cascading failures and enhance the robustness of complex networks under cascading failures.(3)For the problem of the cascading failure caused by node failure in complex networks with variable load and adjustable node weight,a node weight parameter adjustment robustness enhancement strategy based on the minimum node critical capacity threshold in load time-varying networks is proposed.Considering the dynamic characteristics of the load of failed nodes,a model for cascading failures of complex networks with time-varying load and adjustable node weight is constructed.The relationship between node weight parameters and the robustness of load time-varying complex network is revealed.Combined with the optimal weight parameter solution algorithm,the optimal weight parameter value of load time-varying complex network with the minimum node critical capacity threshold is obtained,and the weight parameters of load time-varying complex network are adjusted.Simulation results show that this strategy can effectively enhance the robustness of load time-varying networks under cascading failures.