| Complex network is an effective tool to describe the topology and dynamics of various open complex systems.It has many applications in networked systems such as the Internet,communication networks,power networks,biological networks,and social networks.In the field of control science,networked control system is an important application of complex network.Networked control system(NCS)is a system that transmits data through communication network and forms a control closed loop,which has the advantages of information resource sharing,great interactivity,low system wiring cost,support for remote operation,and easy to expand and maintain.Since a large amount of information transmission depends on the communication network,and the network has the risk of attackers stealing information in it,the existence of network attacks is a great challenge for the security of network control system.In this paper,from the attacker’s point of view,how to impose the false data injection attack to destroy the performance of the system is investigated based on graph theory.Taking the complex network with nodes being multidimensional dynamics as the research object,the selection scheme of the minimum attacked nodes set is proposed.Then the feedback channel and two-channel false data injection attack are respectively studied,and the stability of the system and the destructiveness of the attack are analyzed.Simulations verify the correctness of the theoretical analysis.The main research contents are as follows:For a complex network with nodes being multidimensional dynamics,a scheme for selecting the minimum set of attacked nodes is proposed based on structural controllability theory in order to look for the key nodes and key state variables for network attacks.Firstly,each node with multidimensional state variables is considered as a subnetwork,and some of them are selected for attack.Based on the exact controllability theory,an algorithm is proposed to search the optimal minimum set of driver nodes.Secondly,for networks with root strongly connected components which are perfect matching(pm-r SCC),the analysis in this paper points out that attacking the minimum set of driver nodes may not make the whole network affected by the attack,and there are additional strategies for the selection of attacked nodes.Finally,a general flowchart for designing the minimum set of attacked nodes for multidimensional complex networks is given by integrating structural controllability theory,exact controllability theory and graph theory.The effectiveness of the scheme is demonstrated by simulation examples.For a complex network composed of the discrete-time linear time-invariant Gaussian systems,a feedback channel false data injection attack is designed considering the conclusion of the scheme for selecting minimum attacked node set selection.Firstly,the input matrix of the complex network control system is set up according to the conclusion of the scheme for selecting the minimum attacked node set in Chapter 3.Secondly,based on kalman filter and linear quadratic Gaussian optimal control,an augmented state estimator and an augmented state feedback control strategy are designed on the basis of the output tracking control system.Then,a false data injection attack on the feedback channel is designed to destroy the performance of the system without being detected by residual-based detectors.Finally,theoretical analysis and simulation experiments demonstrate the destructive and stealthiness of the attack when the system matrix is unstable.At last,for a complex network composed of the discrete-time linear time-invariant Gaussian systems,the two-channel false data injection attacks are designed and analyzed theoretically.Firstly,according to the different information of the system model mastered by the attacker,two types of false data injection attack sequences are designed,which are injected into the feedback channel and forward channel,and can avoid the detection of residual-based detector.Then,the stability of the system and the destructiveness of the attack are analyzed,and the conclusion is verified by simulation: when the system matrix is unstable or the forward channel attack matrix is unstable,the attack can destroy the system performance successfully. |
