arXiv Machine Learning

Velocity Ambiguity Profiles: Time-Resolved Bayes-Risk Diagnostics for Flow Matching

The paper introduces the Velocity Ambiguity Profile (VAP), a time‑local Bayes‑risk floor for velocity prediction in flow matching, and decomposes the loss into an irreducible ambiguity term and a reducible excess term. It provides statistical benchmarks for intrinsic local‑regression and Gaussian‑mixture scenarios, and validates the diagnostic with controlled experiments and CIFAR‑100 DINOv2 feature flow, showing that guided time sampling can reduce velocity loss and Fréchet distance.

arXiv Machine Learning
Aug 13

Fine-Tuning Generative Models for Extreme Events via CVaR-Penalized Wasserstein Gradient Flows

arXiv:2608. 11544v1 Announce Type: cross Abstract: We propose CVaR-penalized Generative Particle Algorithm (CVaR-GPA), a robust, tail-agnostic algorithm for fine-tuning generative models to learn heavy-tailed distributions and capture extreme events, requiring no prior knowledge or estimation of the target's tail characteristics.

By Thejani Gamage, Hyemin Gu, Zhizhen Zhang, Ziyu Chen, Markos Katsoulakis, Luc Rey-Bellet
arXiv Machine Learning
Oct 5

When Is Accuracy Evidence? A Unified Theory of Generalisation, Validation, and Information Fusion

The paper introduces a unified exponential framework for generalising K‑fold cross‑validation (CV) accuracy into conservative risk bounds, called gamma‑CUBV. It models dependence between folds via a joint sub‑Gaussian proxy matrix, yielding an effective number of folds and showing that more folds do not always increase evidence when data are strongly correlated. The framework extends to posterior predictor distributions and weighted multi‑source fusion, and is empirically evaluated on linear classifiers trained on heterogeneous multimodal Gaussian mixtures, demonstrating that corrected resubstitution can be tighter than K‑fold CV in low‑sample, high‑heterogeneity settings.

By JM Gorriz
arXiv AI
5d ago

Preconditioned Flow Matching

Preconditioned Flow Matching introduces a precondition-then-match framework that transforms target distributions into more isotropic representations before training flow matching models. By reshaping intermediate distributions, the method improves conditioning, leading to better low-eigenvalue recovery and enhanced performance metrics such as FID, MMD, precision, and recall across Gaussian, Gaussian-mixture, and high-resolution image datasets. The approach is theoretically justified and empirically validated, with ablations showing gains stem from improved geometry rather than extra parameters.

By Shadab Ahamed, Eshed Gal, Md Shahriar Rahim Siddiqui, Simon Ghyselincks, Moshe Eliasof, Eldad Haber
arXiv AI
Aug 24

RiskTraf: Risk-Extrapolated Residual Learning for Multi-Variate Traffic Flow Prediction

RiskTraf introduces a risk-extrapolated residual learning approach for multi-variate traffic flow prediction, leveraging raw flow, speed, and occupancy data from the new PEMSB-3V benchmark. The method freezes a trained spatio-temporal backbone and adds a lightweight residual head that learns from historical speed and occupancy to correct flow predictions across different traffic regimes. Experiments show consistent improvements over various backbones and outperform existing debiasing and distribution-shift adaptation techniques.

By Guangyu Wang, Zhidan Liu
arXiv Computer Vision
Aug 24

Difficulty-Calibrated Interpolation Paths for Conditional Flow Matching

The paper introduces Difficulty-Calibrated Flow Matching, a method that adapts the noise-to-data interpolation schedule in Conditional Flow Matching based on a pilot run’s loss profile. By setting the schedule to the quantile function of this difficulty profile, the training trajectory spends more time where the velocity is hardest to learn. Experiments on CIFAR-10, MNIST, and Fashion‑MNIST show that this calibrated path achieves the best FID on CIFAR‑10 and outperforms all fixed schedules in large‑batch, few‑update settings, where compute is most limited.

By Airin Akter Tania, Md Raihan Khan