Considering different cases of missing values, an extended dominance characteristic relation is proposed in incomplete ordered information systems in this paper. Extended dominance characteristic relation classes are used to realize the granules in the granular computing. Then, definitions of attribute coarsening and refining in incomplete ordered decision systems are presented and an incremental updating method w.r.t. attribute coarsening and refining are analyzed. The updating method of approximations of an upward union of classes is further analyzed according to the changes of extended dominance relation classes.
展开▼
