Reliability analysis of CPS systems under different edge repairing strategies

Cyber-Physical Systems (CPS), such as smart grid is vulnerable to random failures or intentional attacks. The complex characteristics of these systems embed hidden vulnerabilities that threaten their functionality when attacked. In this paper, a reliability analysis model based on network science theory is introduced in interdependent CPS systems. We focus on understanding the structure of CPS systems and studying the underlying network model. Then we propose a rational model for interdependent CPS systems and calculate the number of the fraction of nodes which still can function after attacked. Besides, based on percolation theory, we also study the effect of cascading failures effect and reveal detailed mathematical analysis of failure propagation in such systems. Our simulation shows that high degree addition strategy has the best performance in improving and there is always have an intersection between low degree addition strategy and high degree addition strategy. Also we determine the critical values for different system parameters and then we could select different strategies under different attack ratios to get better reliability. In this way, the proposed reliability analysis model can be effectively utilized for anti-attack and protection purposes in CPS systems. (C) 2019 Elsevier B.V. All rights reserved.