arXiv Machine Learning By Amirardalan Dehghanpour, Arian Noori, Ehsan Tanghatari, Naimeh Omidvar, Hamid R. Rabiee

From Classifier Heads to Encoder Prototypes: Personalized Federated Learning with Head-Derived Clustering

Read the original on arXiv Machine Learning →

The paper introduces HDC‑FL, a personalized federated learning method that clusters clients based on their classifier heads, constructs encoder prototypes for each cluster, and returns a soft mixture of these prototypes to clients while keeping their heads private. The approach requires no additional optimization steps or fine‑tuning and preserves the shared‑encoder trajectory. Experiments on CIFAR‑10 and CIFAR‑100 with ResNet‑18 and MobileNetV2 show that HDC‑FL matches or surpasses state‑of‑the‑art personalized and clustered baselines in macro‑averaged accuracy, worst‑client performance, and bottom‑20% accuracy across various heterogeneity settings.

Machine-generated by The Flow from the publisher's headline and feed description — not written or checked by a human. The full article lives at arXiv Machine Learning.

arXiv AI
Sep 24

A Shared Encoder Is Not a Shared Task: Conditional Comparison for Deep Expert Pools

The paper demonstrates that sharing a deep encoder alone does not eliminate the confounding effects in task-comparison scores. By introducing a conditional two‑discriminator discrepancy within the embedding space, the authors achieve robust detection of task changes, maintaining stability under input rotations and accurately tracking label‑permutation drift. This approach, integrated into a mixture‑of‑heads framework, outperforms traditional novelty triggers and generalizes across multiple backbones and datasets, including ImageNet‑21k ViT‑B/16, DINOv2, and CIFAR‑100.

By Kentaro Oda
arXiv Machine Learning
Oct 8

ORDERS: An Empirical Study of Norm-Rank Aggregation for Personalized Federated Learning

ORDERS is a personalized federated learning configuration that combines a shared backbone, private residual adapters, and a classifier, using geometric weights based on descending update norms, feature alignment, and private‑parameter perturbations. In extensive experiments on CIFAR‑10 and Sent140, ORDERS achieves slightly higher mean client accuracy than baseline methods, with a 5.47% reduction in parameter payload. Ablation studies show limited, dataset‑dependent benefits from norm ranking and alignment, and no clear advantage from perturbations.

By Koffka Khan
arXiv Machine Learning
5d ago

Beyond Scarcity: When Encoder Adaptation Is Worthwhile

The paper introduces a controlled evaluation framework to determine when encoder adaptation is beneficial after correcting for class imbalance in long‑tailed recognition tasks. By separating unique support from representation allocation and comparing classifier‑only versus full‑network continuations, the study shows that encoder updates become worthwhile only when representation allocation is highly imbalanced, a transition that persists across various corrections and scales to ImageNet. The framework uses stage‑specific controls, multiple objectives, whole‑distribution metrics, and hierarchical inference to robustly estimate incremental encoder value.

By Zexing Zhang, Jichao Li, Tianyang Lei, Yiyin Zhang, Kewei Yang
arXiv AI
Sep 24

What Changed? Drift Detection with Real, Virtual, and Incomparable Diagnosis

The paper investigates drift detection in deep learning models, showing that sharing a deep encoder alone does not eliminate confounding in task-comparison scores. By introducing a conditional two‑discriminator discrepancy into the embedding space, the authors create a two‑axis gate that remains stable under input rotations and accurately tracks label‑permutation drift. This approach outperforms traditional exchange or novelty triggers, achieving high AUROC in distinguishing semantic novelty from photometric shift across multiple backbones and datasets.

By Kentaro Oda