In rough set theory, upper and lower approximations for a concept will change dynamically as the information system changes over time. How to update approximations based on the original information is an important task that can help improve the efÞciency of knowledge discovery. This paper focuses on the approach of dynamically updating approximations when attribute values are coarsened or reÞned. Themain contributions include: (1) deÞning coarsening and reÞning attribute values in information systems and introducing the properties and the principles of coarsening and reÞning attribute values; (2) analyzing the properties for dynamic maintenance in terms of upper and lower approximations with coarsening and reÞning attribute values; (3) proposing an incremental algorithm for updating the approximations of a concept as coarsening or reÞning attributes values; and Þnally (4) validating the efÞciency of the proposed approach to handle the dynamic maintenance of the approximations for a given concept.
|Journal||International Journal of Intelligent Systems|
|State||Published - Oct 2010|