Ensembles of classifiers based on rough sets theory and set-oriented database operations

In this paper we present a new approach to construct a good ensemble of classifiers for data mining applications based on rough set theory and database set operations. We borrow the main ideas of rough set theory and redefine them based on the database theory to take advantage of the very efficient set-oriented database operation. Our method first computes a set of reducts which include all the necessary attributes required for the decision categories. For each reduct, a reduct table is generated by removing those attributes which are not in the reduct. Next a novel rule induction algorithm is used to compute the maximal generalized rules for each reduct table and a set of reduct classifiers is formed based on the corresponding reducts. Our rule induction algorithm adopts the "conquer-without-separating " strategy to generate a set of global best rules from the data set. The experimental results indicates that the rough set based approach is very promising for ensemble of classifiers.