A combined analysis method of FMEA and FTA for improving the safety analysis quality of safety-critical software

Software safety analysis methods are used broadly in safety-critical systems to secure software safety and to recognize potential errors during software development, particularly at the early stage. FMEA and FTA are two traditional safety analysis methods, both of which provide a complementary way of identifying errors and tracking their possible influences. They have already been widely adopted in safety-critical industries. However, the effectiveness of FMEA and FTA depends on a complete understanding of the software being analyzed. Unlike hardware safety analysis, software safety analysis is usually a process of iteration. It is more difficult to get a comprehensive understanding of the software being analyzed at the early stage of software life cycle. A combined analysis method of FMEA and FTA was presented in this paper, which could detect more potential errors of software at the early stage. An analysis process which can convert and verify between FMEA and FTA was created. A semi-auto analyzing tool was developed to carry the process. Comparison experiments were carried out to testify the effectiveness of this method, which showed that the combined method proposed by this paper achieved better results.