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As the number of processor cores on supercomputers becomes larger and larger, algorithms with high degree of parallelism attract more attention. In this work, we propose a novel space-time coupled algorithm for solving an inverse problem…

Numerical Analysis · Computer Science 2015-08-26 Xiaomao Deng , Xiao-chuan Cai , Jun Zou

We investigate a second-order accurate time-stepping scheme for solving a time-fractional diffusion equation with a Caputo derivative of order~$\alpha \in (0,1)$. The basic idea of our scheme is based on local integration followed by linear…

Numerical Analysis · Mathematics 2024-07-10 Kassem Mustapha , William McLean , Josef Dick

This study introduces a novel approach for image reconstruction based on a diffusion model conditioned on the native data domain. Our method is applied to multi-coil MRI and quantitative MRI reconstruction, leveraging the domain-conditioned…

Machine Learning · Computer Science 2023-09-06 Wanyu Bian , Albert Jang , Fang Liu

In this paper, we study numerical methods for the homogenization of linear second-order elliptic equations in nondivergence-form with periodic diffusion coefficients and large drift terms. Upon noting that the effective diffusion matrix can…

Numerical Analysis · Mathematics 2025-06-18 Timo Sprekeler , Han Wu , Zhiwen Zhang

Diffusion models have demonstrated their effectiveness across various generative tasks. However, when applied to medical image segmentation, these models encounter several challenges, including significant resource and time requirements.…

Computer Vision and Pattern Recognition · Computer Science 2024-07-10 Tianyu Lin , Zhiguang Chen , Zhonghao Yan , Weijiang Yu , Fudan Zheng

Motivated by their broad applications in reinforcement learning, we study the linear two-time-scale stochastic approximation, an iterative method using two different step sizes for finding the solutions of a system of two equations. Our…

Machine Learning · Computer Science 2020-01-13 Thinh T. Doan

A direct three dimensional EIT reconstruction algorithm based on complex geometrical optics solutions and a nonlinear scattering transform is presented and implemented for spherically symmetric conductivity distributions. The scattering…

Analysis of PDEs · Mathematics 2010-03-22 Jutta Bikowski , Kim Knudsen , Jennifer Mueller

We study a class of high-frequency path functionals for diffusions with singular thresholds or boundaries, where the process exhibits either (i) skweness, oscillating coefficients, and stickiness, or (ii) sticky reflection. The functionals…

Probability · Mathematics 2025-09-16 Alexis Anagnostakis , Sara Mazzonetto

Energy stable flux reconstruction (ESFR) is a high-order numerical method used for solving partial differential equations in computational fluid dynamics. This method is designed to preserve the energy stability of the underlying partial…

Fluid Dynamics · Physics 2023-09-08 Erwan Lambert , Siva Nadarajah

We investigate the problem of reconstructing a 2D piecewise smooth function from its bandlimited Fourier measurements. This is a well known and well studied problem with many real world implications, in particular in medical imaging. While…

Numerical Analysis · Mathematics 2025-03-05 Michael Levinov , Yosef Yomdin , Dmitry Batenkov

In reconstituting k-mer models, extended objects which occupy several sites on a one dimensional lattice, undergo directed or undirected diffusion, and reconstitute -when in contact- by transferring a single monomer unit from one k-mer to…

Statistical Mechanics · Physics 2016-08-02 Amit Kumar Chatterjee , Bijoy Daga , P. K. Mohanty

Subsurface flows are commonly modeled by advection-diffusion equations. Insufficient measurements or uncertain material procurement may be accounted for by random coefficients. To represent, for example, transitions in heterogeneous media,…

Numerical Analysis · Mathematics 2021-01-25 Andrea Barth , Andreas Stein

This paper proposes a reformulation of the scenario-based two-stage unit commitment problem under uncertainty that allows finding unit-commitment plans that perform reasonably well both in expectation and for the worst case realization of…

Optimization and Control · Mathematics 2016-06-21 Ignacio Blanco , Juan M. Morales

While the implementation of single particle coherent diffraction imaging for non-crystalline particles is complicated by current limitations in photon flux, hit rate, and sample delivery a concept of many-particle coherent diffraction…

Disordered Systems and Neural Networks · Physics 2013-02-22 R. P. Kurta , R. Dronyak , M. Altarelli , E. Weckert , I. A. Vartanyants

Many reconstruction problems in signal processing require solution of a certain kind of nonlinear systems of algebraic equations, which we call Prony systems. We study these systems from a general perspective, addressing questions of global…

Numerical Analysis · Mathematics 2014-04-04 Dmitry Batenkov , Yosef Yomdin

We propose in this paper a novel two-stage Projection Correction Modeling (PCM) framework for image reconstruction from (non-uniform) Fourier measurements. PCM consists of a projection stage (P-stage) motivated by the multi-scale Galerkin…

Computer Vision and Pattern Recognition · Computer Science 2017-06-01 Weihong Guo , Guohui Song , Yue Zhang

New one-leg multistep time discretizations of nonlinear evolution equations are investigated. The main features of the scheme are the preservation of the nonnegativity and the entropy-dissipation structure of the diffusive equations. The…

Numerical Analysis · Mathematics 2013-12-02 Ansgar Jüngel , Josipa-Pina Milišić

In previous papers of this series, we presented a formalism able to account for both statistical equilibrium of a multilevel atom and coherent and incoherent scatterings (partial redistribution). aims: This paper provides theoretical…

Solar and Stellar Astrophysics · Physics 2017-11-15 V. Bommier

The speed of sound in two-phase pipe flow systems is often several orders of magnitude greater than the travelling speed of hydraulic information (volume fractions.) Dynamically simulating such flows requires resolution of acoustic and…

Computational Physics · Physics 2018-11-30 Andreas Holm Akselsen

Phase retrieval aims to recover a signal from magnitude or power spectra measurements. It is often addressed by considering a minimization problem involving a quadratic cost function. We propose a different formulation based on Bregman…

Sound · Computer Science 2020-12-01 Pierre-Hugo Vial , Paul Magron , Thomas Oberlin , Cédric Févotte