Quantitative assessment for software safety integrity level with functional safety standards and cost factors

Summary form only given. A safety-related system has not been established with the usual method of calculating the software safety integrity level (abbreviated as SIL) in the functional safety standards, which is determined only by the number of development methods applied to practical safety-related system (abbreviated as SRSs). In this paper, we discuss quantitative assessment for it by applying reliability measurement based on software reliability growth models (abbreviated as SRGM´s) that have been widely and successfully applied to practical software quality management activities. Based on a nonhomogeneous Poisson process (abbreviated as NHPP), the plausible methods of calculating software SIL in the functional safety standard are proposed. Further, we discuss the quantitative method for assuring software safety integrity level with the optimal release policies.