Abstract Ordinal regression is a special machine learning paradigm and its objective is to classify patterns by using a between-class natural order property between the labels. Although many algorithms are proposed, the classical least squares regression (LSR) is not applied to the ordinal regression scenario. In this paper, a discriminative least squares ordinal regression (DLSOR) is proposed by using the cumulative labels and the margin-enlarging technique.Without constraints imposed on the regression function, DLSOR can embed ordinal information and expand between-class margin only through the label transformation. Thus, a high classification accuracy and low mean absolute errors can be guaranteed with the premise that the model complexity of DLSOR is consistent with that of LSR. The experimental results demonstrate the superiority of the proposed method in improving the ordinal regression performance.
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2015, Vol. 28 
