1. Introduction
The multi-label problem is a special classification issue where some instances belong to many classes or include many labels at the same time [1]–[3]. Nowadays, there are mainly two kinds of methods to deal with such a problem. One is to directly generalize binary or multi-class classification algorithms to design multi-label ones based on one optimization problem, for example, rank-SVM [4], ML-KNN [5] [6], ML-BP [7], and so on. The other is to divide a training set into many binary class subsets, to solve all of them using popular binary algorithms, and to integrate all sub-classifiers together. Many researchers have paid more attention to such a kind of decomposition methods since they run very fast in training procedures. Currently two data decomposition strategies are widely adopted: one-versus-other and one-versus-one.