Dominance-based Rough Sets in “*” Incomplete Information System

Abstract

Dominance-based rough set approach is a very important expansion of Pawlak’s rough set approach since the former takes the preference-ordered domains of the attributes into account. In this chapter, the dominance-based rough set approach is introduced into the incomplete information system, in which all unknown values can be compared with any other values in the domains of the corresponding attributes. The “↑” and “↓” descriptors are employed to generate all certain rules from the incomplete information system. Moreover, the expanded dominance relation is also compared with the limited dominance relation, from which we can conclude that the limited dominance-based rough set approach is more suitable than the expanded dominance-based rough set approach when dealing with the incomplete information system.