Resilience Engineering has been attracting its attention since its first introduction in 2006. It has widely been studied both in academic and industrial domains, and the interest is currently directed to relationships between resilience and variety in system controllers (i.e., action variety of systems), based on ideas of Law of Requisite Variety (LoRV) in Cybernetics. However, the relationship between Resilience Engineering and the LoRV is still so conceptual that it is difficult to verify the validity. The purpose of this study is to overcome the gap between the theory and practice. This paper firstly reviews the concept of Resilience Engineering and its relationships with the LoRV. This paper also provides an analysis of a case study by using Functional Resonance Analysis Method (FRAM); this case study is based on a previous research focusing on the variety in terms of actions by people - especially those who are called experts, having investigated the effect of such experts' action variety against variabilities of their surrounding working environment. The analysis result confirmed that the more the action variety increases, the more the experts can be resilient against the variabilities of working environment. Based on the result, this paper concludes with discussions of future prospects of Resilience Engineering. Copyright (C) 2022 The Authors.
