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The simulation of atmospheric flows by means of traditional discretization methods remains computationally intensive, hindering the achievement of high forecasting accuracy in short time frames. In this paper, we apply three reduced order…

Fluid Dynamics · Physics 2023-07-19 Arash Hajisharifi , Michele Girfoglio , Annalisa Quaini , Gianluigi Rozza

Self-supervised video denoising aims to remove noise from videos without relying on ground truth data, leveraging the video itself to recover clean frames. Existing methods often rely on simplistic feature stacking or apply optical flow…

Computer Vision and Pattern Recognition · Computer Science 2024-12-17 Zikang Chen , Tao Jiang , Xiaowan Hu , Wang Zhang , Huaqiu Li , Haoqian Wang

A tomographic technique called full-waveform inversion has recently shown promise as a fast, affordable, and safe modality to image the brain using ultrasound. However, its high computational cost and memory footprint currently limit its…

Medical Physics · Physics 2021-11-09 Letizia Protopapa , Carlos Cueto

We develop a novel gradient-based algorithm for optimizing nonsmooth nonconvex functions where nonsmoothness arises from explicit nonsmooth operators in the objective's analytical form. Our key innovation involves encoding active smooth…

Optimization and Control · Mathematics 2025-05-08 Fengqiao Luo

We present a reduced order modeling (ROM) technique for subsurface multi-phase flow problems building on the recently introduced deep residual recurrent neural network (DR-RNN) [1]. DR-RNN is a physics aware recurrent neural network for…

Computational Engineering, Finance, and Science · Computer Science 2018-10-25 J. Nagoor Kani , Ahmed H. Elsheikh

This paper is concerned with a direct sampling method for imaging the support of a frequency-dependent source term embedded in a homogeneous and isotropic medium. The source term is given by the Fourier transform of a time-dependent source…

Numerical Analysis · Mathematics 2022-12-12 Hongxia Guo , Guanghui Hu , Mengjie Zhao

We revisit the classical problem of Fourier-sparse signal reconstruction -- a variant of the \emph{Set Query} problem -- which asks to efficiently reconstruct (a subset of) a $d$-dimensional Fourier-sparse signal ($\|\hat{x}(t)\|_0 \leq…

Data Structures and Algorithms · Computer Science 2023-11-21 Yeqi Gao , Zhao Song , Baocheng Sun , Omri Weinstein , Ruizhe Zhang

Acquiring temporally high-frequency and spatially high-resolution turbulent wake flow fields in particle image velocimetry (PIV) experiments remains a significant challenge due to hardware limitations and measurement noise. In contrast,…

Machine Learning · Computer Science 2025-08-26 Junle Liu , Chang Liu , Yanyu Ke , Qiuxiang Huang , Jiachen Zhao , Wenliang Chen , K. T. Tse , Gang Hu

In this paper we study the influence of including snapshots that approach the velocity time derivative in the numerical approximation of the incompressible Navier-Stokes equations by means of proper orthogonal decomposition (POD) methods.…

Numerical Analysis · Mathematics 2022-11-01 Bosco García-Archilla , Volker John , Julia Novo

This study presents a comprehensive spatial eigenanalysis of fully-discrete discontinuous spectral element methods, now generalizing previous spatial eigenanalysis that did not include time integration errors. The influence of discrete time…

Fluid Dynamics · Physics 2021-11-30 Niccolò Tonicello , Rodrigo C Moura , Guido Lodato , Gianmarco Mengaldo

Recent advancements in operator-type neural networks have shown promising results in approximating the solutions of spatiotemporal Partial Differential Equations (PDEs). However, these neural networks often entail considerable training…

Machine Learning · Computer Science 2025-05-08 Shuhao Cao , Francesco Brarda , Ruipeng Li , Yuanzhe Xi

The increasing penetration of renewable energy sources, characterised by low inertia and intermittent disturbances, presents substantial challenges to power system stability. As critical indicators of system stability, frequency dynamics…

Systems and Control · Electrical Eng. & Systems 2025-02-19 Xiao Li , Xinyi Wen , Benjamin Schäfer

The use of multitaper estimates for spectral proper orthogonal decomposition (SPOD) is explored. Multitaper and multitaper-Welch estimators that use discrete prolate spheroidal sequences (DPSS) as orthogonal data windows are compared to the…

Fluid Dynamics · Physics 2022-09-14 Oliver T. Schmidt

We propose a new framework for manifold denoising based on processing in the graph Fourier frequency domain, derived from the spectral decomposition of the discrete graph Laplacian. Our approach uses the Spectral Graph Wavelet transform in…

Machine Learning · Computer Science 2016-11-30 Shay Deutsch , Antonio Ortega , Gerard Medioni

The simulation of stochastic wind loads is necessary for many applications in wind engineering. The proper orthogonal decomposition (POD)-based spectral representation method is a popular approach used for this purpose due to its…

Computational Engineering, Finance, and Science · Computer Science 2023-05-11 Thays Guerra Araujo Duarte , Srinivasan Arunachalam , Arthriya Subgranon , Seymour M J Spence

This paper proposes an efficient potential and viscous flow decomposition method for wave-structure interaction simulation with single-phase potential flow wave models and two-phase Computational Fluid Dynamics (CFD) solvers. The potential…

Accurate and efficient modeling of cardiac blood flow is crucial for advancing data-driven tools in cardiovascular research and clinical applications. Recently, the accuracy and availability of computational fluid dynamics (CFD)…

Fluid Dynamics · Physics 2025-07-30 Eneko Lazpita , Jesus Garicano-Mena , Soledad Le Clainche

We consider integrated circuits with semiconductors modeled by modified nodal analysis and drift-diffusion equations. The drift-diffusion equations are discretized in space using mixed finite element method. This discretization yields a…

Numerical Analysis · Mathematics 2010-03-03 Michael Hinze , Martin Kunkel

Inaccurate optical flow estimates in and near occluded regions, and out-of-boundary regions are two of the current significant limitations of optical flow estimation algorithms. Recent state-of-the-art optical flow estimation algorithms are…

Computer Vision and Pattern Recognition · Computer Science 2023-11-02 Fisseha Admasu Ferede , Madhusudhanan Balasubramanian

We propose a new solution to the blind source separation problem that factors mixed time-series signals into a sum of spatiotemporal modes, with the constraint that the temporal components are intrinsic mode functions (IMF's). The key…

Numerical Analysis · Mathematics 2018-06-25 Seth M. Hirsh , Bingni W. Brunton , J. Nathan Kutz