Author

Atsutoshi Kumagai

2 papers indexed here

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#artificial intelligence Apr 2026

Relative Density Ratio Optimization for Stable and Statistically Consistent Model Alignment

The proposed alignment method is statistically consistent and yields significantly tighter convergence guarantees than DDRO, and is based on the relative density ratio between the preferred data distribution and a mixture of the preferred and non-preferred data distributions.

Hiroshi Takahashi, Tomoharu Iwata, Atsutoshi Kumagai et al. · arXiv.org · 0 citations

#artificial intelligence Preprint Sep 2026

AUC Maximization from Biased Positive-unlabeled Data with Confidence

This paper derives an estimator of the AUC risk using biased PU data with confidence, enabling AUC maximization under such bias, and shows that the rewritten AUC risk induces a Bayes-optimal AUC ranking even when the available confidence is any strictly increasing transformation of the true posterior probability.

Atsutoshi Kumagai, Tomoharu Iwata, Hiroshi Takahashi et al. · 0 citations