期刊名称：IAENG International Journal of Computer Science
印刷版ISSN：1819-656X
电子版ISSN：1819-9224
出版年度：2019
卷号：46
期号：2
页码：257-263
出版社：IAENG - International Association of Engineers
摘要：This paper extends and generalizes the approximations of fuzzy rough sets dealing with fuzzy coverings of the universe induced by a weak fuzzy similarity relation. The weak fuzzy similarity relation is considered as a generalization of fuzzy similarity relation in representing a more realistic relationship between two objects in which it has weaker symmetric and transitive properties. Since the conditional symmetry in the weak fuzzy similarity relation is an asymmetric property, there are two distinct fuzzy similarity classes that provide two different fuzzy coverings. The generalization of fuzzy rough sets approximations is discussed based on two interpretations: object-oriented generalization and class-oriented generalization. More concepts of generalized fuzzy rough set approximations are introduced and defined, representing more alternatives to provide level-2 interval-valued fuzzy sets. Moreover, through combining several pairs of proposed approximations of the generalized fuzzy rough sets, it is possible to provide the level-2 type-2 fuzzy sets as an extension of the level-2 interval valued fuzzy sets. Some properties of the concepts are examined.
