Updating reducts in fuzzy beta-covering viamatrix approaches while coarsening and refining a covering element

摘要

In a dynamic environment, knowledge reduction of information systems with variations of object sets, attribute sets and attribute values is an important topic, and related covering reduction of dynamic fuzzy beta-covering approximation space when coarsening and refining a covering element has attracted little attention. How to update the reducts based on the original information is an important problem since it can help to improve the efficiency of knowledge discovery. This paper provides the definitions of the coarsening and refinement of a covering element in the dynamic fuzzy beta-covering approximation space. Then approaches for updating the reducts by the relation character matrix are discussed when coarsening and refining a covering element. And the corresponding algorithms for computing new reducts are derived. Finally, several examples were given to illustrate the validity of the proposed approaches.