A Bilevel Optimization Framework for Imbalanced Data Classification

Fuente: arXiv
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Main Authors: Medlin, Karen, Leyffer, Sven, Raghavan, Krishnan
Format: Preprint
Published: 2024
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author Medlin, Karen
Leyffer, Sven
Raghavan, Krishnan
author_facet Medlin, Karen
Leyffer, Sven
Raghavan, Krishnan
contents Data rebalancing techniques, including oversampling and undersampling, are a common approach to addressing the challenges of imbalanced data. To tackle unresolved problems related to both oversampling and undersampling, we propose a new undersampling approach that: (i) avoids the pitfalls of noise and overlap caused by synthetic data and (ii) avoids the pitfall of under-fitting caused by random undersampling. Instead of undersampling majority data randomly, our method undersamples datapoints based on their ability to improve model loss. Using improved model loss as a proxy measurement for classification performance, our technique assesses a datapoint's impact on loss and rejects those unable to improve it. In so doing, our approach rejects majority datapoints redundant to datapoints already accepted and, thereby, finds an optimal subset of majority training data for classification. The accept/reject component of our algorithm is motivated by a bilevel optimization problem uniquely formulated to identify the optimal training set we seek. Experimental results show our proposed technique with F1 scores up to 10% higher than state-of-the-art methods.
format Preprint
id arxiv_https___arxiv_org_abs_2410_11171
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle A Bilevel Optimization Framework for Imbalanced Data Classification
Medlin, Karen
Leyffer, Sven
Raghavan, Krishnan
Machine Learning
Optimization and Control
Data rebalancing techniques, including oversampling and undersampling, are a common approach to addressing the challenges of imbalanced data. To tackle unresolved problems related to both oversampling and undersampling, we propose a new undersampling approach that: (i) avoids the pitfalls of noise and overlap caused by synthetic data and (ii) avoids the pitfall of under-fitting caused by random undersampling. Instead of undersampling majority data randomly, our method undersamples datapoints based on their ability to improve model loss. Using improved model loss as a proxy measurement for classification performance, our technique assesses a datapoint's impact on loss and rejects those unable to improve it. In so doing, our approach rejects majority datapoints redundant to datapoints already accepted and, thereby, finds an optimal subset of majority training data for classification. The accept/reject component of our algorithm is motivated by a bilevel optimization problem uniquely formulated to identify the optimal training set we seek. Experimental results show our proposed technique with F1 scores up to 10% higher than state-of-the-art methods.
title A Bilevel Optimization Framework for Imbalanced Data Classification
topic Machine Learning
Optimization and Control
url https://arxiv.org/abs/2410.11171