Upper Nearness Degree and Lower Nearness Degree of Fuzzy-Rough Set

摘要

The concepts and models of upper nearness degree and lower nearness degree of fuzzy rough set are introduced, based on the concept of nearness degree of fuzzy set. A method of complementarities and integration of fuzzy set and rough set is given, using given fuzzy−rough model. This method is used in Chinese Medicine diagnoses, and gets the reasonable results that are affirmed by Chinese Medicine experts. This model can be used in Data Mining and Knowledge Discovery in Databases efficiently.