Preliminary Risk Analysis for Software Independent Verification Validation

摘要

We have to face a fact: We do not have a truly effective methodology to ensure software safety or reliability while it is clear that more and more safety critical functions are being implemented as software functions. Software IV&V has been taking attention to be one of the most cost-effective alternatives to ensure software safety or reliability. Typical size of the budget for the independent software analysis is, however, limited by proportion to the total software development cost. Therefore, important technology for accomplishing the success of IV&V effort is to provide methodology to focus on the risk area in the target software and to construct the theory on which the development of the new technology can be based. This paper proposes a technology of preliminary risk analysis for the IV&V tasks and the backbone theory. Nature of typical but hard-to-control cause of the past accidents, that is "error propagation" or "chain of failure events", will also be analyzed. We try defining the "risk" with regard to the possibility of occurring of the error propagation, and quantifying the risk factor. We have studied this proposed technique with real projects such as the International Space Station and the Transfer Vehicle for it, and we will discuss those case studies in this paper.