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In this work we investigate the unique identifiability and stable recovery of a spatially dependent variable-order in the subdiffusion model from the boundary flux measurement. We establish several new unique identifiability results from…

Analysis of PDEs · Mathematics 2025-12-30 Jiho Hong , Bangti Jin , Yavar Kian

Diffusive search for a static target is a common problem in statistical physics with numerous applications in chemistry and biology. We look at this problem from a different perspective and investigate the statistics of encounters between…

Statistical Mechanics · Physics 2023-10-17 Denis S. Grebenkov

The advance of diffusion-based generative models in recent years has revolutionized state-of-the-art (SOTA) techniques in a wide variety of image analysis and synthesis tasks, whereas their adaptation on image restoration, particularly…

Image and Video Processing · Electrical Eng. & Systems 2024-07-09 Luzhe Huang , Xiongye Xiao , Shixuan Li , Jiawen Sun , Yi Huang , Aydogan Ozcan , Paul Bogdan

LiDAR-based 3D point cloud recognition has benefited various applications. Without specially considering the LiDAR point distribution, most current methods suffer from information disconnection and limited receptive field, especially for…

Computer Vision and Pattern Recognition · Computer Science 2023-03-23 Xin Lai , Yukang Chen , Fanbin Lu , Jianhui Liu , Jiaya Jia

We examine the dispersion of Brownian particles in a symmetric two dimensional channel, this classical problem has been widely studied in the literature using the so called Fick-Jacobs' approximation and its various improvements. Most…

Statistical Mechanics · Physics 2019-05-29 M. Mangeat , T. Guérin , D. S. Dean

Biological cells can release compounds into their direct environment, generally inhomogeneously over their cell membrane, after which the compounds spread by diffusion. In mathematical modelling and simulation of a collective of such cells,…

Numerical Analysis · Mathematics 2025-05-13 Qiyao Peng , Sander C. Hille

Various biological cells secrete diffusing chemical compounds into their environment for communication purposes. Secretion usually takes place over the cell membrane in a spatially heterogeneous manner. Mathematical models of these…

Numerical Analysis · Mathematics 2025-11-20 Qiyao Peng , Sander C. Hille

A growing number of biological, soft, and active matter systems are observed to exhibit normal diffusive dynamics with a linear growth of the mean squared displacement, yet with a non-Gaussian distribution of increments. Based on the…

Statistical Mechanics · Physics 2017-04-12 A. V. Chechkin , F. Seno , R. Metzler , I. M. Sokolov

In this work, we look at Score-based generative models (also called diffusion generative models) from a geometric perspective. From a new view point, we prove that both the forward and backward process of adding noise and generating from…

Machine Learning · Computer Science 2023-02-10 Sandesh Ghimire , Jinyang Liu , Armand Comas , Davin Hill , Aria Masoomi , Octavia Camps , Jennifer Dy

Diffusion probabilistic models are traditionally used to generate colors at fixed pixel positions in 2D images. Building on this, we extend diffusion models to point cloud semantic segmentation, where point positions also remain fixed, and…

Computer Vision and Pattern Recognition · Computer Science 2025-03-12 Yong He , Hongshan Yu , Mingtao Feng , Tongjia Chen , Zechuan Li , Anwaar Ulhaq , Saeed Anwar , Ajmal Saeed Mian

We address an original approach for the convergence analysis of a finite-volume scheme for the approximation of a stochastic diffusion-convection equation with multiplicative noise in a bounded domain of $\mathbb{R}^d$ (with $d=2$ or $3$)…

Numerical Analysis · Mathematics 2024-02-20 Caroline Bauzet , Kerstin Schmitz , Aleksandra Zimmermann

We study the problem of particles undergoing Brownian motion in an expanding sphere whose surface is an absorbing boundary for the particles. The problem is akin to that of the diffusion of impurities in a grain of polycrystalline material…

Statistical Mechanics · Physics 2009-11-13 Karl Forsberg , Ali R. Massih

Generating realistic 3D point clouds is a fundamental problem in computer vision with applications in remote sensing, robotics, and digital object modeling. Existing generative approaches primarily capture geometry, and when semantics are…

Computer Vision and Pattern Recognition · Computer Science 2025-09-23 Gunner Stone , Sushmita Sarker , Alireza Tavakkoli

We analyze here in details the probability to find a given number of particles in a finite volume inside a normal or superfluid finite system. This probability, also known as counting statistics, is obtained using projection operator…

Nuclear Theory · Physics 2020-01-22 Denis Lacroix , Sakir Ayik

We introduce a continuous global optimization method to the field of surface reconstruction from discrete noisy cloud of points with weak information on orientation. The proposed method uses an energy functional combining flux-based…

Graphics · Computer Science 2017-08-01 Rongjiang Pan , Vaclav Skala

This paper aims to develop and analyze a numerical scheme for solving the backward problem of semilinear subdiffusion equations. We establish the existence, uniqueness, and conditional stability of the solution to the inverse problem by…

Numerical Analysis · Mathematics 2025-05-07 Xu Wu , Jiang Yang , Zhi Zhou

Generative diffusion models have shown empirical successes in point cloud resampling, generating a denser and more uniform distribution of points from sparse or noisy 3D point clouds by progressively refining noise into structure. However,…

Computer Vision and Pattern Recognition · Computer Science 2024-11-22 Wenqiang Xu , Wenrui Dai , Duoduo Xue , Ziyang Zheng , Chenglin Li , Junni Zou , Hongkai Xiong

Addressing real-world optimization problems becomes particularly challenging when analytic objective functions or constraints are unavailable. While numerous studies have addressed the issue of unknown objectives, limited research has…

Normalizing Flows (NFs) are flexible explicit generative models that have been shown to accurately model complex real-world data distributions. However, their invertibility constraint imposes limitations on data distributions that reside on…

Computer Vision and Pattern Recognition · Computer Science 2022-08-19 Janis Postels , Martin Danelljan , Luc Van Gool , Federico Tombari

We develop an immersed-boundary approach to modeling reaction-diffusion processes in dispersions of reactive spherical particles, from the diffusion-limited to the reaction-limited setting. We represent each reactive particle with a…

Numerical Analysis · Mathematics 2015-06-16 A. Pal Singh Bhalla , B. E. Griffith , N. A. Patankar , A. Donev