Resilience Indices from a Family of Recovery Functions

Defining and measuring resilience using a unified framework has been a topic of intense research. This article presents a perspective on how resilience could be quantitatively assessed through a set of indices. It starts with a brief explanation of resilience in the context of supply chain and a quick summary of existing quantitative measures of resilience. It then discusses how resilience could be quantified in a constructive manner so that the resulting metrics are representative of the performance throughout the system's life cycle. In particular, it is proposed that resilience should be evaluated according to different time periods, i.e. before, during and after a disruption has occurred. Four dimensions of resilience, namely reliability, robustness, recovery and reconfigurability, can then be used to make up a set of indices for resilience. For numerical illustration, these indices are computed based on recovery data arising from Hurricane Sandy in October 2012. Finally, it is postulated that resilience will be the performance metric that complements productivity and sustainability as the third pillar for measuring success of organizations, and in turn, that of sovereign countries in their quests for developing smart cities.