Limited Dominance-based Rough Set Model and Knowledge Reductions in Incomplete Decision System

In this paper, we introduce a new rough set approach, which is called the limited dominance-based rough set model into the incomplete decision system. The limited dominance relation is different from the traditional dominance relation in the incomplete environment because we are on the assumption that the unknown value can only be compared with the maximal or minimal value in the domain of the corresponding attribute. By using the limited dominance-based rough set approach, we can obtain higher accuracies of approximations than using the traditional dominance-based rough set in the incomplete decision system. Further on the problems of knowledge reductions in terms of the limited dominance relation is also addressed. Some numerical examples are employed to substantiate the conceptual arguments.