arXiv Machine Learning

Full-Covariance Smoothing of Bayesian Neural Networks for Online Adaptation

The paper proposes treating a neural network’s layers as time steps in a state‑space model, converting Bayesian training into a smoothing problem. By propagating Gaussian moments forward and applying a Rauch–Tung–Striebel backward pass, weight posteriors are updated in closed form without gradient iterations or replay. The authors extend prior work by introducing a cross‑covariance identity that allows full‑covariance propagation through nonlinear activations, enabling more accurate online adaptation in non‑stationary classification, dynamics learning, and vision‑language‑action policy adaptation.

arXiv Machine Learning
5d ago

Online Learning via Learned Latent Bayesian Tracking

The paper introduces AURA, a meta‑learning framework that learns a low‑dimensional latent state‑space model for the evolution of optimal model parameters under distribution shift. Online adaptation is performed via extended Kalman filtering in this latent space, followed by reconstruction of full model parameters through a learned lifting map, enabling efficient single‑step updates. Experiments on neural wireless receivers and non‑stationary image classification show that AURA improves adaptation speed, accuracy, and computational efficiency compared to existing online learning and Bayesian filtering baselines.

By Guy Gerson, Tomer Raviv, Nir Shlezinger, Tirza Routtenberg, Osvaldo Simeone
arXiv AI
Sep 10

Kalman Delta Networks: Uncertainty-aware Associative Memory

Kalman Delta Networks (KDNs) extend linear attention models by treating associative memory as a linear–Gaussian state‑space system, enabling the Kalman filter to optimally estimate both memory state and its uncertainty. Two GPU‑friendly approximations—Diagonal KDN and Isotropic KDN—use mean‑field variational inference or a single scalar uncertainty per head, respectively, to maintain tractable uncertainty recurrences during linear‑attention scans. Experiments on 750 M and 1.3 B‑parameter models show that KDN variants consistently lower perplexity and raise downstream accuracy compared to existing linear‑attention baselines.

By Ngoc Bui, Tinglin Huang, Rex Ying
arXiv AI
Sep 4

Subspace Inference Enables Efficient Active Reward Learning from Preferences

The paper introduces PreferenceEKF, a sample‑efficient method for active reward learning from human preferences. By framing preference learning as a sequential Bayesian filtering problem, it tracks reward model uncertainty using an extended Kalman filter in a low‑dimensional subspace, avoiding costly posterior inference over the full neural network. Experiments on D4RL and V‑D4RL benchmarks show improved sample efficiency, runtime, scalability, and calibration, with reward models that support competitive offline reinforcement learning policies.

By Yutai Zhou, Erdem B{\i}y{\i}k
arXiv AI
Jun 6

Retry Policy Gradients in Continuous Action Spaces

arXiv:2606. 05888v1 Announce Type: new Abstract: Retry-based objectives such as pass@K and max@K optimize the best return obtained from multiple sampled trajectories, and recent work has shown that they can promote exploration without explicit exploration bonuses.

By Soichiro Nishimori, Paavo Parmas