On the Use of Probabilistic and Deterministic Methods in Risk Analysis.

Deterministic systems are perfectly predictable. Probabilistic systems have some degree of uncertainty in predicting their behaviour and thus involve random variables describing the system elements. Design analyses of industrial systems are traditionally based on strictly deterministic standardised processes. To allow for uncertainties, deterministic "safety factors" are introduced into the computations on the various system elements. In this paper, it is hypothesised that both approaches are modelling the same process through probabilistic intentions may reveal more information since they explicitly incorporate uncertainty. Examples from industrial applications are given. Further, the challenge to system analysis posed by "chaos-theory" is discussed.JRC.(ISIS)-Institute For Systems, Informatics And Safet