Complexity of Design in Safety Critical Interactive Systems: Gathering, Refining, Formalizing Multi-Type and Multi-Source Information while Ensuring Consistency, Reliability, Efficiency and Error-Tolerance

The design of a usable, reliable and error-tolerant interactive safety-critical system is based on a mass of data of multiple natures from multiple domains. In this paper we discuss the complexity and dangers surrounding the gathering and refinement of this mass of data. This complex and currently mostly informal process can be supported using models that allow handling data at a high level of abstraction. However, not all relevant information can be embedded in a single model. Thus, the various models ought to be consistent and coherent with one another. This paper discusses methodological issues. We present a set of issues raised by the gathering and the modeling of data and some issues raised by their consistency. These issues are addressed in a preliminary unifying framework describing the various models, the data embedded in each model and the interconnections of models.