Regional Infrastructures as Complex Systems of Systems: Shared-State Model for Regional Resilience

Present modeling and risk management for resilience of interdependent and interconnected (I-I) physical and cyber-physical infrastructure systems of systems (SoS) often rely on the same risk functions, models, and algorithms used for single systems. This paper introduces an alternative methodology to model, manage, and prioritize safety critical infrastructure systems as complex systems of systems (complex SoS) for resilience planning and operation. The modeling methodology traces all critical I-I in terms of shared/common states (variables), decisions, decision makers, stakeholders, resources, time frame, and organizational setups. A prerequisite for modeling and managing complex SoS is an understanding of the mutual influence resulting from two or more subsystems that share states and other essential entities. Additionally, a novel implementation of fault trees is introduced to prioritize risk without the common need for or knowledge of the associated reliabilities.