Approaches to Knowledge Reduction of Variable Precision Rough Set Model by Ordered Attributes

When the given decision table includes errors or lacks some important information,variable precision rough set(VPRS) model has been proposed as an extension of the classical RS model.This paper introduces variable precision rough set(VPRS) model.lower distribute reduct,upper distribute reduct and distribute reduct(It is called reduct) and relationship among them are discussed.Discernibility matrixes with respect to upper and lower reductions are obtained.Algorithm of ordered attributes is designed to reduct knowledge of decision tables.Finnally,an example shows that this new algorithm is both feasible and effective in practice.