An Incremental Approach for Updating Approximations of Rough Fuzzy Sets under the Variation of the Object Set

The lower and upper approximations are basic concepts in rough set theory, and the approximations will change dynamically over time. Incremental methods for updating approximations in rough set theory and its extension has been received much attention recently. This paper presents an approach for incrementally updating approximations of fuzzy rough sets in dynamic fuzzy decision systems when a single object immigrating and emigrating. Examples are employed to illustrate the proposed approach.