Analyzing the tradeoff between vulnerability and recoverability investments for interdependent infrastructure networks

Critical cyber-physical infrastructure networks such as electric power and water networks form the backbone of a functional society as these networks provide the main resources for economic productivity, healthy communities, and general day-to-day operations. However, (i) these infrastructure networks have become more interdependent on each other in terms of functionality, and (ii) community networks become more dependent on these critical infrastructures in terms of existence. Thus, studying the entirety of their resilience process—both vulnerability and recoverability against a disruption—is of importance, particularly analyzing how investing (i) before to strengthen components versus (ii) afterward to restore disrupted components can affect the resilience of infrastructure networks in terms of system performance and time. This paper takes a first step toward analyzing the tradeoff between reducing vulnerability and enhancing recoverability in interdependent infrastructure networks with multiple time and budget allocations, accounting for not only the performance of the physical networks but also the potentially socially vulnerable communities that rely upon them. The proposed model (i) maximizes a measure of the resilience of the interdependent infrastructure networks, while it (ii) minimizes the total cost associated with the pre- and post-event resource allocation. The model is illustrated with networks in Shelby County, TN, USA.