关键词: 粗糙集, 覆盖, 上近似运算, 广义粗糙集模型

Abstract: Generalized rough sets theory based on covering is extended by the Pawlak rough sets theory, it can deal with uncertainty, imprecise and incomplete information more resonable. This paper presents six type models of generalized rough sets theory based on covering, discusses the upper approximation operation and its properties for every model, and shows the relations among these six type models in the final, which can be treated as supplement and development of generalized rough set theory based on covering.

Key words: rough set, covering, upper approximation operation, generalized rough sets model