The SERENE method

The SERENE (SafEty and Risk Evaluation using bayesian NEts) method is concerned with the functional safety of complex systems, particularly programmable electronic systems which fall within the scope of draft IEC 61508 and similar standards. Functional safety concerns the ability of a system to carry out the actions necessary to achieve or maintain a safe state (IEC 1995, adapted). In a complex system the demonstration of functional safety must take account of both random and systematic failures. Systematic failures include those that result from design errors. All complex systems are potentially subject to systematic failures, but this difficulty applies most of all to software, for which systematic failures are the only form of failure.

The SERENE project produced a decision support method, with a supporting tool, for quantifying safety of complex systems using Bayesian Networks.

The method helps safety analysts and engineers combine diverse forms of evidence together in order to predict safety or risk at any stage in the development life-cycle. A number of key benefits are provided to users of the SERENE method:

• rationally combine different sources and types of evidence in a single model

• identify weaknesses in the safety argument such that it can be improved

• identify weaknesses in products and processes to aid process improvement

• specify degrees of confidence associated with predictions

• provide a sound basis for rational discussion and negotiation about the systems development and deployment

Two articles talking about SERENE :

• Formalisation de l'argumentaire de sûreté d'un système programmé critique à l'aide d'un réseau bayésien, selon la méthode SERENE (Buissou (2000))

• Assessment of a Safety-Critical System Including Software:A Bayesian Belief Network for Evidence Sources (Bouissou et al. (1999))

Bibliography

M. Bouissou, F. Martin, and A. Ourghanlian. Assessment of a safety-critical system including software: a bayesian belief network for evidence sources. In Reliability and Maintainability Symposium (RAM'99). 1999. ↩

Marc Buissou. Formalisation de l'argumentaire de sûreté d'un système programmé critique à l'aide d'un réseau bayésien, selon la méthode serene. Revue de l’Electricité et de l’Electronique (REE), february 2000. ↩