Safety driven design with UML and STPA

TalkSystem Theoretic Process Analysis (STPA) is increasingly being used in diverse industrial sectors for the analysis of existing complex technical systems. At the Safety Critical Systems Research Lab of IAMP, we successfully applied STPA in several projects having a focus on the safety assessment of already designed and implemented systems. In accordance with proposals coming from other groups, we also strongly believe that STPA could ideally be used in the design phases of the systems engineering process, hence supporting the paradigm of safety driven design. We certainly can state that every systems engineer has an intrinsic motivation to design safe and secure systems. With regard to the increasing complexity of today’s systems and the inadequateness of most of the established hazard analysis methods to cope with that in an efficient and timely way, it must not come as a surprise that the safety driven design paradigm remains on the wish list rather than to become reality. We realize that the primary goal to reach in order to achieve safety guided design is to empower system engineers to analyze safety issues directly from their perspective and within their mindset. Approaches merely focusing on embedding safety processes into development processes will have little chance of success if this goal is not reached. Allowing system engineers to handle safety in a “natural” manner will automatically bring safety engineering and system engineering closer together. Model driven design with UML and SysML is nowadays recognized as being the state of the art in technical systems engineering. As these tools are typically adopted from software system engineering it is primarily the software engineering community which proposes to use them for system safety – and security – matters, but not only. In this talk we show how model driven design with UML and SysML can be extended to safety driven design by incorporating STPA directly into the design process