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John Stephan

6 accepted papers

2025

Adaptive Gradient Clipping for Robust Federated Learning

ICLR 2025spotlight

Robust federated learning aims to maintain reliable performance despite the presence of adversarial or misbehaving workers. While state-of-the-art (SOTA) robust distributed gradient descent (Robust-DGD) methods were proven theoretically optimal, their empirical success has often relied on pre-aggreg…

Cited by 0SourcePDFScholar
2025

Towards Trustworthy Federated Learning with Untrusted Participants

ICML 2025poster

Resilience against malicious participants and data privacy are essential for trustworthy federated learning, yet achieving both with good utility typically requires the strong assumption of a trusted central server. This paper shows that a significantly weaker assumption suffices: each pair of parti…

Cited by 0SourcePDFScholar
2023

Fixing by Mixing: A Recipe for Optimal Byzantine ML under Heterogeneity

AISTATS 2023poster

Byzantine machine learning (ML) aims to ensure the resilience of distributed learning algorithms to misbehaving (or Byzantine) machines. Although this problem received significant attention, prior works often assume the data held by the machines to be homogeneous, which is seldom true in practical s…

Cited by 72SourcePDFScholar
2023

On the Privacy-Robustness-Utility Trilemma in Distributed Learning

ICML 2023poster

The ubiquity of distributed machine learning (ML) in sensitive public domain applications calls for algorithms that protect data privacy, while being robust to faults and adversarial behaviors. Although privacy and robustness have been extensively studied independently in distributed ML, their synth…

Cited by 27SourcePDFScholar
2023

Robust Collaborative Learning with Linear Gradient Overhead

ICML 2023poster

Collaborative learning algorithms, such as distributed SGD (or D-SGD), are prone to faulty machines that may deviate from their prescribed algorithm because of software or hardware bugs, poisoned data or malicious behaviors. While many solutions have been proposed to enhance the robustness of D-SGD…

2022

Byzantine Machine Learning Made Easy By Resilient Averaging of Momentums

ICML 2022spotlight

Byzantine resilience emerged as a prominent topic within the distributed machine learning community. Essentially, the goal is to enhance distributed optimization algorithms, such as distributed SGD, in a way that guarantees convergence despite the presence of some misbehaving (a.k.a.,

Cited by 76SourcePDFScholar