Learning apparatus, trained model generation method, classification apparatus, classification method, and computer-readable recording medium

Abstract

The learning apparatus for machine learning a score function to be used for two-class classification includes a score function optimization unit that updates, by setting, as an index, a total value of a value obtained by multiplying an AUC by a weight λ which is a positive real number and a value obtained by multiplying a pAUC by a weight (1−λ), a parameter of the score function through machine learning that is performed, using training data, so as to maximize the index, while decreasing the value of the weight λ. The AUC indicates an area of a region on a horizontal axis side of a curve obtained by changing a threshold for determining a positive example and a negative example in the score function. The pAUC is a value of the AUC when the value of the false positive rate is set to a specific fixed value.