HAZOP Analysis of UML-Based Software Architecture Descriptions of Safety-Critical Systems

Safety-critical systems which are systems that may harm the environment they are operating in are commonplace. Standards and regulations for developing software for safety-critical systems usually require restricted programming languages and formal methods. For reasons of scale and for coping with the complexities of large systems it may be beneficial to use modern object-oriented techniques in their development. A good match for such techniques is the semi-formal modeling notation Unified Modeling Language (UML). In order to use UML, the notation and associated techniques need to be reconciled with traditional techniques for safety-critical development. This paper looks at the commonly used Hazard and Operability (HAZOP) technique for hazard analysis and presents a systematic way of performing HAZOP on UML models together with a concrete interpretation of HAZOP for UML-based software architecture descriptions.