New Method for the Measurement on the Roughness of Rough Set

Rough set theory is an important technique for knowledge discovery in databases. The measurement of the uncertainty of knowledge is one of the important issues in rough set theory. The definitions of entropy and the conditional entropy in the process of probability are given, and the meanings of entropy and the conditional entropy are explained in this paper. In addition, the new definition of the rough entropy of set X is given by considering the granularity of knowledge modules caused by binary relations and the granularity of the boundary of X.