PANDORA 2: THE TIME OF PRIORITY-OR GATES

Pandora is a recently proposed technique that extends classical Fault Tree Analysis to incorporate the effects of the temporal ordering of failure events. In this paper, we extend the conceptual foundation of Pandora with a new Priority-OR (POR) gate and we introduce the concept of a Temporal Truth Table as a mechanism that can be used to prove equivalence of expressions in Pandora logic. We also show how logical reduction can be performed using a set of temporal laws in the new logic and how such analysis can enrich the results of an extended FTA performed on a generic example that exhibits both PAND and POR failure characteristics.