FOSSIL: Regret-minimizing weighting for robust learning under imbalance and small data

Fuente: arXiv
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Main Authors: Cha, J., Lee, J., Cho, J., Shin, J.
Format: Preprint
Published: 2025
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author Cha, J.
Lee, J.
Cho, J.
Shin, J.
author_facet Cha, J.
Lee, J.
Cho, J.
Shin, J.
contents Imbalanced and small data regimes are pervasive in domains such as rare disease imaging, genomics, and disaster response, where labeled samples are scarce and naive augmentation often introduces artifacts. Existing solutions such as oversampling, focal loss, or meta-weighting address isolated aspects of this challenge but remain fragile or complex. We introduce FOSSIL (Flexible Optimization via Sample Sensitive Importance Learning), a unified weighting framework that seamlessly integrates class imbalance correction, difficulty-aware curricula, augmentation penalties, and warmup dynamics into a single interpretable formula. Unlike prior heuristics, the proposed framework provides regret-based theoretical guarantees and achieves consistent empirical gains over ERM, curriculum, and meta-weighting baselines on synthetic and real-world datasets, while requiring no architectural changes.
format Preprint
id arxiv_https___arxiv_org_abs_2509_13218
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle FOSSIL: Regret-minimizing weighting for robust learning under imbalance and small data
Cha, J.
Lee, J.
Cho, J.
Shin, J.
Machine Learning
Imbalanced and small data regimes are pervasive in domains such as rare disease imaging, genomics, and disaster response, where labeled samples are scarce and naive augmentation often introduces artifacts. Existing solutions such as oversampling, focal loss, or meta-weighting address isolated aspects of this challenge but remain fragile or complex. We introduce FOSSIL (Flexible Optimization via Sample Sensitive Importance Learning), a unified weighting framework that seamlessly integrates class imbalance correction, difficulty-aware curricula, augmentation penalties, and warmup dynamics into a single interpretable formula. Unlike prior heuristics, the proposed framework provides regret-based theoretical guarantees and achieves consistent empirical gains over ERM, curriculum, and meta-weighting baselines on synthetic and real-world datasets, while requiring no architectural changes.
title FOSSIL: Regret-minimizing weighting for robust learning under imbalance and small data
topic Machine Learning
url https://arxiv.org/abs/2509.13218