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Owing to the deep integration of the information and communication technologies, power cyber-physical systems (CPSs) have become smart but are vulnerable to cyber attacks. To correctly assess the vulnerability of power CPSs and further study feasible countermeasures, we verify that a data-driven target attack on a nonlinear Granger causality graph (NGCG) can be constructed successfully, even if adversaries cannot acquire the configuration information of the systems. A NGCG is a unified framework for the processing and analysis of nonlinear measurement data or datasets and can be used to evaluate the significance of power nodes or lines. In addition, an algorithm including data-driven parameter estimation, noise removal and data reconstruction based on symplectic geometry is introduced to make the NGCG a parameter-free and noise-tolerant method. In particular, three new indexes on the weight analysis of the NGCG are defined to quantitatively evaluate the significance of power nodes or lines. Finally, several case studies of a nonlinear simulation model and power systems in detail verify the effectiveness and superiority of the proposed data-driven target attack. The results show the proposed target attack can select the key attack targets more accurately and lead to physical system collapse with the least number of attack steps. [ABSTRACT FROM AUTHOR]

In this paper, considering two typical attack strategies of a DoS jammer, a new kind of H ∞ control problem is studied for Cyber–Physical Systems (CPSs) with different transmission mechanism encountering DoS jamming attacks. By defining a concept of working subcycle, the concrete attack strategies of a DoS jammer can be generated by choosing different reasonable value combinations in a unified framework according to the DoS jammer's energy efficiency and stealthiness. Then, for two different transmission mechanisms, namely the time-triggered mechanism (TTM) and the event-triggered mechanism (ETM), in which CPSs can employ in its wireless channels, two DoS jammers employ different attack strategies and launch SINR-based DoS jamming attacks to decrease the quality of wireless communication. Considering the case that the CPSs do not know the DoS jammers' attack strategies, the corresponding H ∞ observer-based controllers are designed by using an attack-tolerant mechanism to achieve the desired H ∞ disturbance attenuation level, and the controller design problems are transformed to auxiliary convex optimization problems. Finally, numerical simulations are presented to demonstrate the effectiveness of the proposed H ∞ control methods and the varying of system performance under different interference power chosen by the DoS jammers. • The DoS jamming attacks, the channel fading and the external disturbance are considered. • Working subcycle is defined to express the random and reactive attack strategies in a unified framework. • The effect caused by DoS jamming attacks depends on the DoS jammer's interference power. • Without knowing the DoS jammers' attack strategy, H ∞ controllers are designed for CPSs. • The H ∞ control methods can address the CPSs encountering or not encountering DoS jamming attacks. [ABSTRACT FROM AUTHOR]

In this paper, we research the resilient control problem for cyber-physical system (CPS) under denial-of-service (DoS) attacks. These malicious DoS attacks aim to impede the communication of measurement data or control data in order to endanger the functionality of the closed-loop system. Meanwhile, in order to save network resources, event-triggered mechanism has been introduced into this CPS. By exploiting the relationship between cyber system and physical system, we aim to design the resilient controller and resilient control strategy to tolerate a class of DoS signals characterised by probability without serious hazard to the stability and performance of CPS. Furthermore, considering that the transition probability of cyber state is unknown, the on-policy reinforcement learning method – SARSA (State-Action-Reward-State-Action) – is used to solve this problem. Thus a resilient control algorithm that integrates game theory, robust control theory, event-triggered control method and SARSA learning method is presented to enhance the security and robustness of the CPS. At last, the numerical simulation and experimental results are given to demonstrate the validity and applicability of the proposed algorithm. [ABSTRACT FROM AUTHOR]

Cyber‐Physical Systems (CPSs) are vulnerable to malicious network attacks due to tight combination of cyber‐system and physical system through a more open network communication. In this paper, a guaranteed cost control problem for a CPS under DoS jamming attacks is solved via both state feedback and output feedback methods. Specifically, an energy constraint DoS jammer with clear periodic attack strategy is proposed to attack wireless channel and to degrade the system performance. Without knowing the DoS jammer's attack strategy, a passive attack‐tolerant mechanism is established, and the corresponding state feedback and output feedback controllers are designed to achieve guaranteed cost control for the CPS with inherent packet dropouts under DoS jamming attacks. Finally, numerical examples are presented to demonstrate the effectiveness of the guaranteed cost controllers. [ABSTRACT FROM AUTHOR]

• The DoS jamming attacks and the channel fading are considered. • Working subcycle is defined to express the random attack strategy in a unified framework. • DoS jamming attacks occur on the measurement and control channels simultaneously. • Without knowing the DoS jammers' attack strategy, controllers are designed for CPSs; and • This control method can also address the CPS only with inherent packet dropouts. Increasing attention has been paid to the security issues of Cyber-Physical Systems in recent years. In this paper, consider the case that a DoS jammer who has a limited energy budget and employs random attack strategy to interfere the wireless fading channels in a CPS, while the CPS does not know the DoS jammer's attack strategy. By defining a concept of working subcycle, two types of a random attack strategy which decided by the DoS jammer can be described in a unified framework. An attack-tolerant mechanism is established based on the stored packet in the corresponding receivers. By establishing an attack-tolerant mechanism based on the stored packet in the corresponding receivers and adopting an observer-based control method, a guaranteed cost controller is designed to ensure that the CPS under DoS jamming attacks is exponentially mean-square stable and the corresponding cost function value is less than a specified upper bound, and the design problem of the controller is converted into a solving of a convex optimization problem. Numerical examples are presented to demonstrate the effectiveness of the proposed control method under different random attack strategies, finally. [ABSTRACT FROM AUTHOR]