An Integrated Safety Strategy to Model Driven Development with SysML

A building architect would not design a building without due consideration of existing safety standards related to the utilities (gas, electricity and water). These aspects of the building's design cut across the structural aspects of the building. The design of the building (commonly represented as a blueprint) contains aspects of structure, plumbing, wiring and implicit usage (layout of rooms, doors, stairs and windows etc.) within a single model using different notations to separate the different aspects. Similarly, no systems engineer would build a system and then add safety. Additionally, when using separation of concerns of decomposition to analyse the system, safety is not limited to a single or even many areas of the system. It needs to be inherent in all areas of the system. This paper will demonstrate how the UML and SysML can be used to construct a single coherent model of a system allowing the many different disciplines (e.g. safety engineers, systems engineers, hardware engineers, software engineers) to work in isolation whilst working together. Using an integrated database and ergonomic profiling to support all the disciplines it is possible to create bespoke views of the model (based on whatever notation is preferred by a single discipline) and to enforce the rules that cut across to other disciplines. This paper will focus on the safety aspects of a SysML design and techniques for identifying risks, how these are managed and ultimately mitigated resulting in a safety case for the system under construction. It will include several illustrations of the techniques described above.