INFERENCE APPARATUS USING OCCURRENCE RATE DATA AND DEGREE OF RELAVANCE DATA

An apparatus for correctly inferring the causes of a failure of driving machine or the like. Each time a true cause is found, the data on the degree of relevance of the cause is so corrected that the degree of the other causes becomes high and those of the other causes become low. On the basis of the data on the failure rate and the data on the degree of the relevance, the certainty of each cause is inferred by a first inferring means. The data on the predicted failure rate of each cause and the data on the actual failure rate are compared, and the certainty of each cause is inferred by a second inferring means in such a way that the certainty of a cause having less errors becomes higher. The certainties inferred by the first and second inferring means are weighted in a predetermined way. Based upon these weighted certainties, final certainties are inferred.