In developing an expert system, one of the most difficult tasks is to gather domain knowledge from multiple experts. To cope with this
problem, in this study, a set of rules in a knowledge base is defined to check and integrate the corresponding relationships given by multiple experts. While interpreting these rules, we shall call the values that are less than 3 the “weak side”, and those
that are greater than 3 the “strong side”. In addition, the value 3 is treated as being on both sides. There are four conditions for integrating
the corresponding relationships given by multiple experts as follows: (1) Integration rules for the same value with
different degrees of confidence, (2) Integration rules for the values on the same side with different degrees of confidence, (3) Integration
rules for the values with “X”, and (4) Integration rules for the values on different sides. Hence, we shall introduce each condition of integrating corresponding relationships in detail as follows: