Analysis of and Decision-Making on the Operational Reliability of Cyber-Physical Systems

Abstract

Matters concerned with analyzing the operational reliability and recovery process of cyber-physical systems (CPS) are addressed. The proposed approach is based on dividing the CPS life cycle into time intervals with linking them to pre-emergency, emergency, restored and predicted states. The CPS serviceability is restored with respect to extremely critical and mission-critical equipment. In carrying out the analysis, graphs representing the states of cybernetic and physical components are introduced. Differential equations linking the probability of returning into a serviceable state with failure rates and restorations of various types are derived. The solution of the appropriate ordinary differential equations yields a clear graphical interpretation in the time domain and shows the changes in the probability with which the system components transfer from one state to another at different CPS life cycle time slices. By using the developed flow chart of making decisions on restoring or replacing the corresponding component, a reasonable choice can be made among possible options of actions aimed at restoring the serviceability of a multicomponent system. An algorithm for implementing the method has been developed and tested on a numerical example.