Considerations for engineered resilience from examples of resilient systems

Abstract

Everyday commercial, civil, and defense enterprises are faced with disruptive events that have the potential to degrade or altogether impede business as usual. In an increasingly interconnected and interdependent world, where systems/ system-of-systems provide functionality enabling operational capabilities, complexity is commonplace; and the ability to anticipate and therefore manage all potential disruptions becomes untenable. Recognizing this dilemma, organizations are trying to understand and infuse the properties of resiliency in their culture, processes, and assets. Resilience is a widely used term and in general is understood as the ability to operate through some adverse condition. Accordingly, engineered resilience, the notion of designing resilience into a system from the outset, is a frequent subject of analysis and research in the systems engineering and acquisition community. This paper explores the question of what it means to purposefully engineer resilient systems by examining systems that displayed resilience, thus continuing to provide a capability even through disruptions. The examples - an acquisition system and an operational system - are analyzed with respect to various resiliency concepts. This includes applying several resiliency definitions to the example systems and identifying metrics for measuring resilience which introduces the notion of drift, timeliness, and process as important resiliency factors. Finally, observations related to engineering resilient systems are offered.