Cyber–Physical Systems: The Last Defense

The development, evolution, and operation of a cyber–physical system are cross-domain, holistic processes. The process encompasses all elements of a cyber–physical system, including computation infrastructure, software, interfaces to the physical world, human interactions, and safety and security engineering. The process is holistic because it must assure conceptual integrity and correct interoperability across all elements of the CPS. Unfortunately, at every stage of this process, vulnerabilities can be introduced into the system (due to negligence, mistakes, lack of skills, malicious activities, etc.). These dormant vulnerabilities can cause failures of the runtime system, possibly resulting in damage, loss of property or life, safety accidents, or security incidents. A promising approach to mitigate such risks is runtime anomaly detection using artificial intelligence/machine learning. This tutorial paper introduces the fundamental concepts of AI/ML anomaly detection and describes the corresponding intervention mechanisms. Automated intervention mechanisms are the last line of defense against failures, faults, malfunctions, and malicious activities—and their unfortunate consequences. The paper remains at the conceptual level and defers implementation details to subsequent publications. The content addresses advanced students (at the master’s level) and researchers entering this fascinating field.