Resilience enhancer: Conceptualization, categorization, and quantitative evaluation with case studies of subsea systems

• Resilience enhancer, as a new concept, is proposed and defined. • Four categorization methods are presented for systematic identification of resilience enhancers. • Quantitative evaluation metrics of resilience enhancers are developed. • Case studies are conducted to illustrate the functions of the new concept. This article introduces a new concept of resilience enhancer, as an entity and/or non-entitative approach for a sociotechnical system to provide additional resilience to the system during disruptive events. Inspired by the role of safety barrier in process safety management, resilience enhancer is expected to facilitate systematic identification, evaluation, and comparison of resilience improvement strategies using unified metrics. Resilience enhancers are categorized by their operational phases, implementation formats, locations and operational modes. Effectiveness and probable effectiveness coefficient are then proposed as the quantifiable metrics for assessing them. Case studies of subsea transportation systems demonstrate the practical applications of the new concept and its evaluation framework, in which six distinct resilience enhancers are quantitatively analyzed and compared. The results reveal variations in the effectiveness of resilience enhancers, emphasizing the importance of context-based selection. This study advances methodologies for resilience engineering and provides a foundation for future research in designing and operating resilient sociotechnical systems.