System-theoretic safety analysis in agile software development

Abstract

Agile software development (ASD) has gained a good reputation for a number of years due to its higher customer satisfaction, lower defect rates, faster development times and as a solution to rapidly changing requirements. Thus, ASD arouses interests from safety-critical industries due to a fast changing market and upcoming customised requirements. However, applying ASD to develop safety-critical systems (SCS) is contro- versial. Most of practitioners in SCS prefer using traditional development processes together with a standardised safety assurance process by satisfying the norms, such as IEC 61508. Existing research is striving for a consistency or a hybrid model between ASD and norms. However, the traditional safety assurance cannot work well without a stable architecture. ASD has a con- stantly changing architecture, which makes the integration of traditional safety assurance in ASD a bottleneck, especially the execution of safety analysis. In this dissertation, we aim to propose a process model called S-Scrum, which is mainly based on integrating a System-Theoretic Process Analysis (STPA) to face the changing architectures when using ASD for developing SCS.