An Early Design Stage UML-Based Safety Analysis Approach for High Assurrance Software Systems

High-assurance computer systems fulfill security, safety, fault-tolerant, and real-time properties. Analysis of these properties is typically performed in isolation. An integrated analysis of all the properties is a challenge that can be addressed by expressing these properties in a common integrated framework. The Unified Modeling Language is a standard modeling language which exhibits such a capability. In this paper we focus on using the Unified Modeling Language to analyze the safety properties of high-assurance systems. In particular we are interested in the study of software faults propagation and their functional level effects. In previous work we have developed the Failure Propagation and Simulation Approach to study whether a particular fault will propagate through the design and cause system-level functional failures. Mapping between different Unified Modeling Language diagrams is the central concept behind the approach. This paper briefly introduces the Failure Propagation and Simulation Approach and presents in detail the executable models developed to automate the simulation process. These executable models are built using the notations of the Event Sequence Diagram, one of the established reliability and safety analysis techniques for sequence progression.