1 System Importance Measures : Development and Initial Application

Our research focuses on developing System Importance Measures (SIMs) to characterize resilience. Our measures are applicable to systems and systems-of-systems that are characterized by diversity in nodes and functions. The system importance measures help identify and rank components or systems that have the most impact on different aspects of the overall resilience. Because systems-of-systems (SoS) pose a particularly challenging and interesting resilience design problem, we use SoS to illustrate the development of the SIMs and to demonstrate their application. Section 2 provides background on SoS and introduces some of the terminology we will use. In Section 3, we present three System Importance Measures (SIMs) that rank or prioritize the constituent components or systems based on their resilience significance. We say that a system is resilience significant if a disruption of the system contributes significantly to measures of SoS performance. These measures help determine “where” in the SoS resources need to be targeted so that they provide the most benefit in the event of disruptions. In Section 4, we demonstrate the use of the SIMs using two case studies. Section 5 discusses our current effort and Section 6 concludes our report.