An extension of semantic proximity for fuzzy functional dependencies

Semantic proximity proposed by Liu is an approach to determine fuzzy functional dependencies. However, the approach that utilizes fuzzy values with the form of interval numbers might still have some data out of the range. An extension of semantic proximity with the concept of fuzzy sets at degree alpha set by database designers is presented, giving it a more flexibility in calculating the degree of proximity between fuzzy values. Then, we may determine fuzzy functional dependencies and prove the inference rules to be sound and complete. Furthermore, we present the use of a compressing rule to help reduce the range of fuzzy sets to be closer to the real situation.