Formal Requirements and Constraints Modelling in FORM-L for the Engineering of Complex Socio-Technical Systems

Abstract

Socio-technical systems combine behaviour and actions from human operators, physical processes (e.g., thermodynamic or electromagnetism), computing and data communication. One often uses expression "cyber-physical system", or "systems of systems" in the case of systems composed of socio-technical systems of their own that each have different stakeholders, owners and lifecycles, but that must cooperate in order to achieve what none can achieve independently. Complex systems are systems that require the cooperation and coordination of multiple individuals, multiple teams, multiple engineering disciplines and multiple stakeholders to be fully understood in all necessary aspects. This coordination must be ensured all along the lifetime of the system, from scoping studies that aim at determining the nature of the system needed, to deconstruction. For systems such as power plants or passenger aircrafts, this lifetime may cover several decades, during which the system needs to be operated, maintained, retrofitted and upgraded, by multiple successive generations. EDF has developed a FOrmal Requirements Modelling Language (FORM-L) to help address this issue for what concerns dynamic phenomena. This paper provides a brief introduction to FORM-L and its underlying methodology, illustrated with short examples.