CHASe: Client Heterogeneity-Aware Data Selection for Effective Federated Active Learning

Fuente: arXiv
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Main Authors: Zhang, Jun, Wang, Jue, Li, Huan, Xie, Zhongle, Chen, Ke, Shou, Lidan
Format: Preprint
Published: 2025
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author Zhang, Jun
Wang, Jue
Li, Huan
Xie, Zhongle
Chen, Ke
Shou, Lidan
author_facet Zhang, Jun
Wang, Jue
Li, Huan
Xie, Zhongle
Chen, Ke
Shou, Lidan
contents Active learning (AL) reduces human annotation costs for machine learning systems by strategically selecting the most informative unlabeled data for annotation, but performing it individually may still be insufficient due to restricted data diversity and annotation budget. Federated Active Learning (FAL) addresses this by facilitating collaborative data selection and model training, while preserving the confidentiality of raw data samples. Yet, existing FAL methods fail to account for the heterogeneity of data distribution across clients and the associated fluctuations in global and local model parameters, adversely affecting model accuracy. To overcome these challenges, we propose CHASe (Client Heterogeneity-Aware Data Selection), specifically designed for FAL. CHASe focuses on identifying those unlabeled samples with high epistemic variations (EVs), which notably oscillate around the decision boundaries during training. To achieve both effectiveness and efficiency, \model{} encompasses techniques for 1) tracking EVs by analyzing inference inconsistencies across training epochs, 2) calibrating decision boundaries of inaccurate models with a new alignment loss, and 3) enhancing data selection efficiency via a data freeze and awaken mechanism with subset sampling. Experiments show that CHASe surpasses various established baselines in terms of effectiveness and efficiency, validated across diverse datasets, model complexities, and heterogeneous federation settings.
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id arxiv_https___arxiv_org_abs_2504_17448
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle CHASe: Client Heterogeneity-Aware Data Selection for Effective Federated Active Learning
Zhang, Jun
Wang, Jue
Li, Huan
Xie, Zhongle
Chen, Ke
Shou, Lidan
Machine Learning
Databases
Distributed, Parallel, and Cluster Computing
Active learning (AL) reduces human annotation costs for machine learning systems by strategically selecting the most informative unlabeled data for annotation, but performing it individually may still be insufficient due to restricted data diversity and annotation budget. Federated Active Learning (FAL) addresses this by facilitating collaborative data selection and model training, while preserving the confidentiality of raw data samples. Yet, existing FAL methods fail to account for the heterogeneity of data distribution across clients and the associated fluctuations in global and local model parameters, adversely affecting model accuracy. To overcome these challenges, we propose CHASe (Client Heterogeneity-Aware Data Selection), specifically designed for FAL. CHASe focuses on identifying those unlabeled samples with high epistemic variations (EVs), which notably oscillate around the decision boundaries during training. To achieve both effectiveness and efficiency, \model{} encompasses techniques for 1) tracking EVs by analyzing inference inconsistencies across training epochs, 2) calibrating decision boundaries of inaccurate models with a new alignment loss, and 3) enhancing data selection efficiency via a data freeze and awaken mechanism with subset sampling. Experiments show that CHASe surpasses various established baselines in terms of effectiveness and efficiency, validated across diverse datasets, model complexities, and heterogeneous federation settings.
title CHASe: Client Heterogeneity-Aware Data Selection for Effective Federated Active Learning
topic Machine Learning
Databases
Distributed, Parallel, and Cluster Computing
url https://arxiv.org/abs/2504.17448