Figure 2.

The average AUROC and the average rank of each method on the banana data as the number of positive train examples increases. The OP-SVM and OP-SVM (CS) showed generally high and fairly steady AUROC over the range of positive example numbers. Their performance degraded very little even with very small numbers of positive examples. The TC-SVM and TC-SVM (CS) improved, as more positive examples were available for model training. With more than 40 positive training examples, the TC-SVM eventually achieved the highest AUROC and outperformed the other approaches. AUROC, area under the receiver operating characteristic curve; OP-SVM, one-plus-class support vector machine; TC-SVM, two-class support vector machine classification.