On the Definition of Resilience in Systems

摘要

In the current era of world-wide terrorism, the terms "vulnerability" and "resilience" have become common in the parlance of risk analysis, and various attempts have been made to define and to quantify them. In an article published in Risk Analysis, "On the Definition of Vulnerabilities in Measuring Risks to Infrastructures," I offered the following definitions: Vulnerability refers to the inherent states of a given system (e.g., physical, technical, organizational, and cultural) that can be exploited by an adversary to adversely affect (cause harm or damage to) that system. Intent is the desire or motivation of an adversary to attack a target and to cause adverse effects. Capability is the ability and capacity to attack a target and to cause adverse effects. Threat denotes the intent and capability to adversely affect (cause harm or damage to) the system by adversely changing its states. A threat with adverse effects to a vulnerable system may lead to risk. (Throughout the rest of this article, the term threat will connote a threat with adverse effects.) Resilience, however, has been defined in the literature in many different ways.