An Integrated Process Model for the Systems Development Requiring Simultaneous Consideration of the SE Process and Safety Requirements

We are concerned with the development of complex large-scale systems with safety-critical requirements. Therefore, we have to study how to satisfy both the systems engineering (SE) and safety requirements. To do so, we developed an integrated process model for the systems development by integrating the standard SE process from ISO/IEC 15288 and the hazard analysis techniques for systems safety. Based on the concepts of the systems life cycle, the processes and associated activities, the model was designed to have hierarchical structure with three levels and was represented by the enhanced functional flow block diagrams (EFFBD's). The three levels are called the life cycle view, the process view, and the activity view from the top downwards. Note that the interface between the processes of SE and safety was realized in the process views that are at the second level of the model. In addition, the traceability between each level can be easily maintained. A database schema was obtained to reflect the integrated process and the model was implemented by a tool COREreg. To verify the developed model, a set of actions have been carried out, including timeline analysis, unaddressed leaf-level requirements check, and traceability check. The confirmed traceability can be useful later when the requirement changes in which case a modification of the existing model would be easy. As a result, the integrated process model specifies the required processes and activities of SE and safety, respectively, and also the interface/interaction between them. All the processes and activities are carried out concurrently and iteratively.