Modeling and Stochastic Analysis of Embedded Systems Emphasizing Failure Severity, Coincident Failures and Usage-Profiles

& Conclusions-The increasingly ubiquitous use of software systems has created the need of being able to depend on them more than before, and of being able to measure just how dependable they are. Knowing that the system is reliable is absolutely necessary for safety/mission-critical systems, where any kind of failure may result in an unacceptable loss of human life. This study models and analyzes the Anti-lock Braking System of a passenger vehicle. Special emphasis is laid on modeling extra-functional characteristics of severity of failures, coincident failures and usage-profiles-the goal is to develop an approach that is realistic, generic and extensible for this application domain. The strategy of modeling these characteristics (using empirical data) is innovative in terms of the approach used to integrate them into the Stochastic Petri Net and Stochastic Activity Network formalisms. The validation approach compares the results from the two separate models. The results were found to be comparable and confirm that the effect of modeling coincident failures, failure severity and usage-profiles is evident in determining overall system reliability. This work also provides a solid basis for modeling more complex systems and carrying out further supplementation and analysis.