arXiv AI

FedReason: Large Language Models as Weight-Space Meta-Aggregators for Heterogeneous Federated Learning

FedReason introduces a large language model (LLM) that dynamically selects aggregation rules for federated learning by inspecting client model weights in a sandboxed environment. The LLM evaluates candidate rules on a small proxy dataset and submits a Python program that the server executes until the next call, defaulting to FedAvg if the output is invalid. Experiments on CIFAR-10 and CIFAR-100 with ResNet-18 under various heterogeneity and Byzantine scenarios show FedReason outperforming FedAvg by an average of 1.26 percentage points and matching the best server‑side rule on CIFAR‑100, while incurring modest API costs.

arXiv Machine Learning
Oct 16

Federated Art Chase: Privacy Leakage and Data Poisoning in Federated Fine-Tuning

The paper investigates privacy and integrity risks in federated fine‑tuning of a pretrained MobileNetV4 model on Quick, Draw! data. It shows that a single client update can reveal private labels, that label‑count recovery degrades with more clients, and that backdoor and label‑flipping attacks can succeed under FedAvg but are mitigated by FLTrust. The study also demonstrates a live poisoning session using Indigma’s FedMaestro orchestrator.

By Vasileios Perifanis, Nikolaos Pavlidis
arXiv Machine Learning
Aug 20

FedLNS: Leverage LayerNorm Signature Modeling to Mitigate Adversarial Manipulation in Federated LLMs

FedLNS is a server‑side framework that screens federated learning updates by representing each client’s contribution through changes in trainable normalization‑layer parameters, creating lightweight signatures that can be compared against a history‑aware cross‑client reference. The method requires no extra client‑to‑server communication, raw data, or labeled attack examples, and after screening, the remaining full‑model updates are aggregated with standard federated learning rules. Experiments on GPT‑style, BERT‑style, and LLaMA‑style models with 200 clients demonstrate that FedLNS achieves lower test perplexity than six baselines even when 40% of the population performs target manipulation under both IID and non‑IID data partitions.

By Kai Li, Jong-Ik Park, Carlee Joe-Wong, Wei Ni, Falko Dressler
arXiv Machine Learning
Sep 16

SWB-DM: A Calibrated Sliced-Wasserstein-Barycenter Aggregator with Delayed-Momentum Caching for Byzantine-Robust Federated Learning under Partial Participation

The paper introduces SWB-DM, a Byzantine‑robust federated learning aggregator that treats each slice of a client update as a one‑dimensional distribution, computes a trimmed Wasserstein barycenter across clients, and uses a medoid‑based gauge‑fixing step to recover coordinate identity. It further incorporates delayed‑momentum caching to decouple robustness from the specific clients sampled each round. Extensive experiments on CIFAR‑10, CIFAR‑100, FEMNIST, and a 500‑client scalability run reveal distinct failure modes of existing defenses and demonstrate that SWB‑DM achieves significant gains, especially when compared under equal round budgets.

By Saranraj S, Saranya M S, Alex David S, Ajay Kumar A
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 AI
Sep 10

Typed Federated Artifacts for the Agentic Web:Sharing Tool-Routing Knowledge Across Frozen,Heterogeneous LLM Agents

The paper proposes typed federated artifacts—schema‑validated objects with per‑field privacy and dispute resolution—to enable tool‑routing knowledge sharing among frozen, heterogeneous LLM agents. By replacing flat text prompts with typed fields, the authors achieve near‑centralized routing performance on StableToolBench while reducing data size to 20 MB JSON per client. The study also highlights that a simple TF‑IDF classifier can outperform LLM routing on labeled benchmarks, indicating limitations in current evaluation methods.

By Abhijit Chakraborty, Ni Trieu, Vivek Gupta
arXiv AI
Sep 2

FedReview: Review and Dispose Poisoned Updates without Validation Datasets or Historic Knowledge

FedReview is a review-based mechanism for federated learning that identifies and removes poisoned model updates without needing a server-side validation dataset or historic client knowledge. In each training round, the server randomly selects reviewers who evaluate incoming updates on their own training data, rank them, and estimate how many low-quality updates are likely poisoned. The server then aggregates these rankings via majority voting to filter out suspicious updates during model aggregation, enabling robust global model training even in adversarial settings.

By Tianhang Zheng, Yanlu Li, Bohan Deng, Baochun Li