Uncertainty reduction techniques in an expert system for fault tree construction

Logical fault trees are used for obtaining reliability- oriented representations of complex engineered systems. The construction of fault trees is time-consuming and may be affected by several sources of potential error. An expert system has been designed to reduce and control uncertainties that emerge during the construction process. Fuzzy algebra and multiple-valued logic provide the formal instruments for solving problems encountered and for organizing the information which may become available to the analyst. Consequently, a multiplevalued fuzzy logical tree is proposed as a general representation of the engineered system. The tree can be compressed and reduced to the crisp binary case to establish comparisons and perform evaluations as required.