A modeling framework for the resilience analysis of networked systems-of-systems based on functional dependencies

Critical infrastructures provide services that are essential for the support of everyday activities in modern societies. Being the result of a continuous process of integration of diverse technologies and organizations, they require a multi-disciplinary, systemic approach in order to be understood. In this respect, one of the most challenging issues is the analysis of infrastructures under disturbance or malfunctioning, and their ability to resist, react and recover, in a word the resilience. This paper presents a methodology of resilience analysis of systems of systems, with infrastructures as a special instance. A conceptual representation of the infrastructure, based on the functional relationships among its components, is given and then analyzed with respect to its structural and dynamic properties. Most critical and vulnerable components are identified. The response of the system to failure propagation is simulated in order to check if it is able to cope with them and recover in a resilient fashion. The analysis outcomes are used for a resilience-informed review of the infrastructure.