Ce livre aborde d'abord la problematique de la prise en compte des incertitudes relatives aux donnees de fiabilite des composants pour l'evaluation de la surete de fonctionnement des systemes complexes en general et les Systemes Instrumentes de Securite en particulier. Le second objectif de ce livre est l'introduction d'une methodologie d'aide a la conception des Systemes Instrumentes de Securite en optimisant le choix des composants et la structure pour le respect du Niveau d'Integrite de securite exige."

The first part of the book defines the concept of uncertainties and the mathematical frameworks that will be used for uncertainty modeling. The application to system reliability assessment illustrates the concept. In the second part, evidential networks as a new tool to model uncertainty in reliability and risk analysis is proposed and described. Then it is applied on SIS performance assessment and in risk analysis of a heat sink. In the third part, Bayesian and evidential networks are used to deal with important measures evaluation in the context of uncertainties.