Architecture-driven System Safety Analysis In Combination Of FTA And Extended Fussy-FMEA

With the demand for the integrated assessment of software quality attributes in the Internet era, the software trustworthiness analysis in the users’ point of view, such as reliability, safety, correctness, etc, requires a more synthetic analysis and extension way. Meanwhile, in the architecture description language level, analysis of software architecture and relevant properties also faces new challenges. As a significant feature of software system, safety, especially in safety-critical systems, is analysed and assessed by many approaches, including Fault Tree Analysis(FTA), Failure Mode and Effects Analysis(FMEA) and so on. However, the existing safety analysis can no longer meet current needs both in qualitative and quantitative level.Given all the problems above, focused on safety, a software architecture driven synthetic safety analysis is proposed according to the requirements in software trustworthy analysis. Combining FTA and FMEA, this systematic safety analysis approach, a two-way means in both top-down and bottom-up directions, achieves advantages of these two classical methods. Besides, the dimensions of traditional FMEA are extended by introducing the Human Factors. And by using fuzzy theory into assessment and calculatation of the failure modes, further improvement of traditional FMEA is achieved.In the case study, the synthetic safety analysis proposed is utilized into a large-scale distributed command system. Through the comparison between the proposed analysis and the conventional one, the significance and advantages of this method are highlighted.Finally, after modeling software systems using Breeze/ADL, this architecture description language is extended by adding safety attributes to support the safety assessment. Also a plug-in is developed in the Tool Breeze to implement the tool-level support for safety analysis.