Selective Collaboration for Robust Federated Learning

Nazarii Tupitsa, Samuel Horváth, Martin Takáč, Eduard Gorbunov

Keywords: federated learning, robust aggreagation

Abstract: Federated Learning (FL) revolutionizes machine learning by enabling model training across decentralized data sources without aggregating sensitive client data. However, the inherent heterogeneity of client data presents unique challenges, as not all client contributions positively impact model performance. In this work, we propose a novel algorithm, Merit-Based Federated Averaging (\Algn), which dynamically assigns aggregation weights to clients based on their data distribution's relevance to a target objective. By leveraging stochastic gradients and solving an auxiliary optimization problem, our method adaptively identifies beneficial collaborators, ensuring efficient and robust learning. We establish theoretical convergence guarantees under mild assumptions and demonstrate that \Algn achieves superior convergence by harnessing the advantages of diverse yet complementary datasets. Empirical evaluations highlight its ability to mitigate the adverse effects of outlier and adversarial clients, paving the way for more effective and resilient FL in heterogeneous environments.

Submission Number: 101