Systems Engineering for the Digital Age

Chapter 16Exploiting Formal Modeling in Resilient System Design: Key Concepts, Current Practice, and Innovative Approach

Azad M. Madni¹ and Michael Sievers²

¹ Astronautics, Aerospace, and Mechanical Engineering, University of Southern California, Los Angeles, CA 90089, USA

² Systems Architecting and Engineering, University of Southern California, Los Angeles, CA 90089, USA

Introduction

Resilience is the ability of a system or system of systems (SoS) to continue to provide useful service despite disruptions through planning and preparation; absorbing disruption impacts; recovering service to pre‐disruption performance levels; and evolving system configuration, use, and personnel training by adapting to and/or exploiting newly gained knowledge (Madni and Jackson 2009; Westrum 2007). Along with integrity, safety, reliability, fault‐tolerance, and maintainability, resilience is key to dependable and available systems (Avizienis et al. 2004). It is important to note at the outset, that the resilience property is different from fault‐tolerance and robustness.

Fault‐tolerance, one means of achieving system dependability, comprises methods to avoid failures by detecting errors and providing means for masking or recovering from faults that are root causes of those errors. Generally speaking, fault‐tolerance which is “inward” looking protects against fault conditions within a system. Resilience, on the other hand, allows continued trustworthy operation despite disruptive events that ...