Comparative Evaluation of Resilience Quantification Methods for Infrastructure Systems

Resilience engineering has become an important field representing a new way of understanding and management of safety. The rising interest for resilience engineering and the rapid application of the respective theoretical basis to several application cases alters the traditional approach of infrastructure systems’ risk management. In this context, the quantification of resilience is a challenging issue, which is still far from considered as adequately addressed in the respective literature and, therefore, requires a better insight. The aim of this research is to provide such an insight into currently established and proposed methods for quantifying resilience of infrastructure systems and suggest a methodological framework that effectively responds to the requirements of resilience measuring. To achieve this aim, resilience engineering is shortly presented and discussed, in terms of definition and characteristics and an insight is provided into various resilience quantification methods, such as probabilistic, graph theory, fuzzy inference, and analytical methods. Discussion over these methods reveals their strengths and weaknesses in quantifying resilience. A major finding of this research is that current methods are, mostly, incomplete and largely dependent on concepts and approaches, which emanate from other well-established and well-elaborated methodological frameworks, thus failing to provide solutions in the context of resilience engineering. On the other hand, it is proposed that entropy theory constitutes a framework, which better captures the underlying interrelations of systems modules and, therefore, constitutes a more appropriate and effective framework for quantifying resilience of infrastructure systems.