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This paper considers the iterative solution of linear systems arising from discretization of the anisotropic radiative transfer equation with discontinuous elements on the sphere. In order to achieve robust convergence behavior in the…

Numerical Analysis · Mathematics 2021-03-11 Jürgen Dölz , Olena Palii , Matthias Schlottbom

We reconsider the problem of diffusion of particles at constant speed and present a generalization of the Telegrapher process to higher dimensional stochastic media ($d>1$), where the particle can move along $2^d$ directions. We derive the…

Disordered Systems and Neural Networks · Physics 2009-10-31 S. Anantha Ramakrishna , N. Kumar

Textures in images can often be well modeled using self-similar processes while they may at the same time display anisotropy. The present contribution thus aims at studying jointly selfsimilarity and anisotropy by focusing on a specific…

Data Analysis, Statistics and Probability · Physics 2015-06-16 S. G. Roux , M. Clausel , B. Vedel , S. Jaffard , P. Abry

Recent score-based diffusion models (SBDMs) show promising results in unpaired image-to-image translation (I2I). However, existing methods, either energy-based or statistically-based, provide no explicit form of the interfered intermediate…

Computer Vision and Pattern Recognition · Computer Science 2023-08-07 Shikun Sun , Longhui Wei , Junliang Xing , Jia Jia , Qi Tian

We present here the measurement of the diffusivity of spherical particles closely confined by narrow microchannels. Our experiments yield a two-dimensional map of the position-dependent diffusion coefficients parallel and perpendicular to…

Fluid Dynamics · Physics 2014-06-20 Simon L Dettmer , Stefano Pagliara , Karolis Misiunas , Ulrich F Keyser

While continuous diffusion models have achieved remarkable success, discrete diffusion offers a unified framework for jointly modeling text and images. Beyond unification, discrete diffusion provides faster inference, finer control, and…

We demonstrate a novel approach to the reconstruction of scanning probe x-ray diffraction tomography data with anisotropic poly crystalline samples. The method involves reconstructing a voxel map containing an orientation distribution…

Discrete diffusion models have recently shown significant progress in modeling complex data, such as natural languages and DNA sequences. However, unlike diffusion models for continuous data, which can generate high-quality samples in just…

Machine Learning · Computer Science 2025-03-20 Anji Liu , Oliver Broadrick , Mathias Niepert , Guy Van den Broeck

Anomalous diffusion occurs at very different scales in nature, from atomic systems to motions in cell organelles, biological tissues or ecology, and also in artificial materials, such as cement. Being able to accurately measure the…

Machine Learning · Computer Science 2021-08-09 Òscar Garibo i Orts , Miguel A. Garcia-March , J. Alberto Conejero

Recently, the transfer application of diffusion models in super-resolu-tion tasks has faced the problem ofdecreased fidelity. Due to the inherent randomsampling characteristics ofdiffusion models, direct application in super-resolu-tion…

Computer Vision and Pattern Recognition · Computer Science 2025-07-17 Chao Yang , Yong Fan , Qichao Zhang , Cheng Lu , Zhijing Yang

The aim of this paper is the rigorous derivation of a stochastic non-linear diffusion equation from a radiative transfer equation perturbed with a random noise. The proof of the convergence relies on a formal Hilbert expansion and the…

Analysis of PDEs · Mathematics 2014-05-13 Arnaud Debussche , Sylvain De Moor , Julien Vovelle

Results from Direct Numerical Simulations of particle relative dispersion in three dimensional homogeneous and isotropic turbulence at Reynolds number $Re_\lambda \sim 300$ are presented. We study point-like passive tracers and heavy…

Fluid Dynamics · Physics 2015-02-19 L. Biferale , A. S. Lanotte , R. Scatamacchia , F. Toschi

This work aims to improve the efficiency of text-to-image diffusion models. While diffusion models use computationally expensive UNet-based denoising operations in every generation step, we identify that not all operations are equally…

Computer Vision and Pattern Recognition · Computer Science 2024-02-21 Amirhossein Habibian , Amir Ghodrati , Noor Fathima , Guillaume Sautiere , Risheek Garrepalli , Fatih Porikli , Jens Petersen

We study spreading dynamics of nematic liquid crystal droplets within the framework of the long-wave approximation. A fourth order nonlinear parabolic partial differential equation governing the free surface evolution is derived. The…

Fluid Dynamics · Physics 2013-07-19 Te-Sheng Lin , Lou Kondic , Uwe Thiele , Linda J. Cummings

We propose a second-order temporally implicit, fourth-order-accurate spatial discretization scheme for the strongly anisotropic heat transport equation characteristic of hot, fusion-grade plasmas. Following [Du Toit et al., Comp. Phys.…

Computational Physics · Physics 2024-09-11 L. Chacon , Jason Hamilton , Natalia Krasheninnikova

In this paper we consider a diffusion process obtained as a small random perturbation of a dynamical system attracted to a stable equilibrium point. The drift and the diffusive perturbation are assumed to evolve slowly in time. We describe…

Probability · Mathematics 2016-10-23 Mark Freidlin , Leonid Koralov

The Pearson family of ergodic diffusions with a quadratic diffusion coefficient and a linear force are characterized by explicit dynamics of their integer moments and by explicit relaxation spectral properties towards their steady state.…

Statistical Mechanics · Physics 2023-08-14 Cecile Monthus

In image processing, one of the most challenging tasks is to render an image's semantic meaning using a variety of artistic approaches. Existing techniques for arbitrary style transfer (AST) frequently experience mode-collapse,…

Computer Vision and Pattern Recognition · Computer Science 2024-08-08 Onkar Susladkar , Gayatri Deshmukh , Sparsh Mittal , Parth Shastri

We study the horizontal expansion of vertically confined ultra-cold atoms in the presence of disorder. Vertical confinement allows us to realize a situation with a few coupled harmonic oscillator quantum states. The disordered potential is…

In this paper we introduce and study a new feature-preserving nonlinear anisotropic diffusion for denoising signals. The proposed partial differential equation is based on a novel diffusivity coefficient that uses a nonlocal automatically…

Analysis of PDEs · Mathematics 2019-07-23 Giacomo Aletti , Monica Moroni , Giovanni Naldi