How to Collaborate: Towards Maximizing the Generalization Performance in Cross-Silo Federated Learning

Fuente: arXiv
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Main Authors: Sun, Yuchang, Kountouris, Marios, Zhang, Jun
Format: Preprint
Published: 2024
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author Sun, Yuchang
Kountouris, Marios
Zhang, Jun
author_facet Sun, Yuchang
Kountouris, Marios
Zhang, Jun
contents Federated learning (FL) has attracted vivid attention as a privacy-preserving distributed learning framework. In this work, we focus on cross-silo FL, where clients become the model owners after training and are only concerned about the model's generalization performance on their local data. Due to the data heterogeneity issue, asking all the clients to join a single FL training process may result in model performance degradation. To investigate the effectiveness of collaboration, we first derive a generalization bound for each client when collaborating with others or when training independently. We show that the generalization performance of a client can be improved only by collaborating with other clients that have more training data and similar data distribution. Our analysis allows us to formulate a client utility maximization problem by partitioning clients into multiple collaborating groups. A hierarchical clustering-based collaborative training (HCCT) scheme is then proposed, which does not need to fix in advance the number of groups. We further analyze the convergence of HCCT for general non-convex loss functions which unveils the effect of data similarity among clients. Extensive simulations show that HCCT achieves better generalization performance than baseline schemes, whereas it degenerates to independent training and conventional FL in specific scenarios.
format Preprint
id arxiv_https___arxiv_org_abs_2401_13236
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle How to Collaborate: Towards Maximizing the Generalization Performance in Cross-Silo Federated Learning
Sun, Yuchang
Kountouris, Marios
Zhang, Jun
Machine Learning
Distributed, Parallel, and Cluster Computing
Federated learning (FL) has attracted vivid attention as a privacy-preserving distributed learning framework. In this work, we focus on cross-silo FL, where clients become the model owners after training and are only concerned about the model's generalization performance on their local data. Due to the data heterogeneity issue, asking all the clients to join a single FL training process may result in model performance degradation. To investigate the effectiveness of collaboration, we first derive a generalization bound for each client when collaborating with others or when training independently. We show that the generalization performance of a client can be improved only by collaborating with other clients that have more training data and similar data distribution. Our analysis allows us to formulate a client utility maximization problem by partitioning clients into multiple collaborating groups. A hierarchical clustering-based collaborative training (HCCT) scheme is then proposed, which does not need to fix in advance the number of groups. We further analyze the convergence of HCCT for general non-convex loss functions which unveils the effect of data similarity among clients. Extensive simulations show that HCCT achieves better generalization performance than baseline schemes, whereas it degenerates to independent training and conventional FL in specific scenarios.
title How to Collaborate: Towards Maximizing the Generalization Performance in Cross-Silo Federated Learning
topic Machine Learning
Distributed, Parallel, and Cluster Computing
url https://arxiv.org/abs/2401.13236