P-Graph Approach to Allocation of Inoperability in Urban Infrastructure Systems

Abstract

Inoperability input-output modeling (IIM) was introduced as a methodology for determining ripple effects propagating through interdependent infrastructure systems as a result of disruptive events such as natural disasters. It is based on the dimensionless metric of inoperability which indicates degree of failure along a scale ranging from 0 to 1. Previous approaches have focused on calibration of interdependencies based on records of economic statistics; IIM has also been used mainly for identifying the vulnerability and criticality of system components. More recent work has demonstrated that the IIM framework can be the basis for optimal allocation of inoperabiltiy in order to minimize damage caused by disruptions. In this work, we propose a P-graph methodology derived from IIM. Interdependency coefficients are integrated within a P-graph model to enable limited capacity of infrastructure following a disruption to be optimally allocated. We demonstrate this methodology using a literature case study.