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The finite volume methods are frequently employed in the discretization of diffusion problems with interface. In this paper, we firstly present a vertex-centered MACH-like finite volume method for solving stationary diffusion problems with…

Numerical Analysis · Mathematics 2016-09-07 Jie Peng , Shi Shu , Haiyuan Yu , Chunsheng Feng , Mingxian Kan , Ganghua Wang

Several problems in machine learning are naturally expressed as the design and analysis of time-evolving probability distributions. This includes sampling via diffusion methods, optimizing the weights of neural networks, and analyzing the…

Optimization and Control · Mathematics 2026-05-28 Gabriel Peyré

Reward-based fine-tuning steers a pretrained diffusion or flow-based generative model toward higher-reward samples while remaining close to the pretrained model. Although existing methods are derived from different perspectives, we show…

Machine Learning · Computer Science 2026-05-08 Jeongjae Lee , Jinho Chang , Jeongsol Kim , Jong Chul Ye

The contact process is a non-equilibrium Hamiltonian model that, even in one dimension, lacks an exact solution and has been extensively studied via Monte Carlo simulations, both in steady-state and time-dependent scenarios. Although the…

Statistical Mechanics · Physics 2025-04-15 Roberto da Silva , Eliseu Venites Filho , Henrique Almeida Fernandes , Paulo F. Gomes

Learning from expert demonstrations is a promising approach for training robotic manipulation policies from limited data. However, imitation learning algorithms require a number of design choices ranging from the input modality, training…

Robotics · Computer Science 2024-09-12 Eugenio Chisari , Nick Heppert , Max Argus , Tim Welschehold , Thomas Brox , Abhinav Valada

Our goal is to develop a flux limiter of the Flux-Corrected Transport method for a nonconservative convection-diffusion equation. For this, we consider a hybrid difference scheme that is a linear combination of a monotone scheme and a…

Numerical Analysis · Mathematics 2023-06-06 Sergii Kivva

We consider Ramp Metering (RM) at the microscopic level subject to vehicle following safety constraints for a freeway with arbitrary number of on- and off-ramps. The arrival times of vehicles to the on-ramps, as well as their destinations…

Probability · Mathematics 2023-06-21 Milad Pooladsanj , Ketan Savla , Petros A. Ioannou

We introduce a simple yet powerful calculational tool useful in calculating averages of ratios and products of characteristic polynomials. The method is based on Dyson Brownian motion and Grassmann integration formula for determinants. It…

Mathematical Physics · Physics 2015-12-22 Jacek Grela

Monte Carlo radiative transfer (MCRT) simulations are a powerful tool for determining the appearance of astrophysical objects, analyzing the prevalent physical conditions within them, and inferring their properties on the basis of real…

Instrumentation and Methods for Astrophysics · Physics 2023-12-13 Anton Krieger , Sebastian Wolf

Efficiently identifying accurate correspondences between point clouds is crucial for both rigid and non-rigid point cloud registration. Existing methods usually rely on geometric or semantic feature embeddings to establish correspondences…

Computer Vision and Pattern Recognition · Computer Science 2026-04-10 Haihua Shi , Qianliang Wu

Knowledge of the noise distribution in magnitude diffusion MRI images is the centerpiece to quantify uncertainties arising from the acquisition process. The use of parallel imaging methods, the number of receiver coils and imaging filters…

Computer Vision and Pattern Recognition · Computer Science 2018-10-03 Samuel St-Jean , Alberto De Luca , Max A. Viergever , Alexander Leemans

Estimating means on Riemannian manifolds is generally computationally expensive because the Riemannian distance function is not known in closed-form for most manifolds. To overcome this, we show that Riemannian diffusion means can be…

Other Statistics · Statistics 2025-02-19 Frederik Möbius Rygaard , Steen Markvorsen , Søren Hauberg , Stefan Sommer

Continuous diffusion models are commonly acknowledged to display a deterministic probability flow, whereas discrete diffusion models do not. In this paper, we aim to establish the fundamental theory for the probability flow of discrete…

Machine Learning · Computer Science 2023-11-08 Pengze Zhang , Hubery Yin , Chen Li , Xiaohua Xie

Diffusion models trained on different, non-overlapping subsets of a dataset often produce strikingly similar outputs when given the same noise seed. We trace this consistency to a simple linear effect: the shared Gaussian statistics across…

Machine Learning · Computer Science 2026-02-04 Binxu Wang , Jacob Zavatone-Veth , Cengiz Pehlevan

In this paper, we examine the cause of the border effect observed in many mobility models used to construct simulations of ad hoc networking protocol performance. We specify conditions under which a node mobility model must produce spatial…

Networking and Internet Architecture · Computer Science 2009-09-29 Michael Hohensee

The conditional diffusion model (CDM) enhances the standard diffusion model by providing more control, improving the quality and relevance of the outputs, and making the model adaptable to a wider range of complex tasks. However, inaccurate…

Machine Learning · Computer Science 2024-08-07 Weifeng Xu , Xiang Zhu , Xiaoyong Li

Modelling diffusion processes in heterogeneous media requires addressing inherent discontinuities across interfaces, where specific conditions are to be met. These challenges fall under the purview of Mathematical Analysis as…

Analysis of PDEs · Mathematics 2023-06-28 Vincenzo Bianca , Edgard A. Pimentel , José Miguel Urbano

Study on the electronic transport of a large scale two dimensional system by the transfer matrix method (TMM) based on the Sch\"{o}rdinger equation suffers from the numerical instability. To address this problem, we propose a renormalized…

Mesoscale and Nanoscale Physics · Physics 2014-02-12 Miao Gao , Gui-Ping Zhang , Zhong-Yi Lu

Implementing multicomponent diffusion models in reacting-flow simulations is computationally expensive due to the challenges involved in calculating diffusion coefficients. Instead, mixture-averaged diffusion treatments are typically used…

Diffusion-based visuomotor policies excel at learning complex robotic tasks by effectively combining visual data with high-dimensional, multi-modal action distributions. However, diffusion models often suffer from slow inference due to…

Robotics · Computer Science 2025-08-08 Haoran Ding , Noémie Jaquier , Jan Peters , Leonel Rozo