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We study the magneto-rotational instability (MRI) driven dynamo in a geometrically thin disc ($H/R\ll 1$) using stratified zero net flux (ZNF) shearing box simulations. We find that mean fields and EMFs oscillate with a primary frequency…

High Energy Astrophysical Phenomena · Physics 2024-07-22 Prasun Dhang , Abhijit Bendre , Kandaswamy Subramanian

In groundwater contaminant remediation and risk assessment, it is important to identify parameters of the contaminant source and hydraulic conductivity field by solving an inverse problem. However, if the dimensionality of the inverse…

Optimization and Control · Mathematics 2015-06-17 Jiangjiang Zhang

Context. The recently developed test-field method permits to compute dynamo coefficients from global, direct numerical simulations. The subsequent use of these parameters in mean-field models enables us to compare self-consistent dynamo…

Solar and Stellar Astrophysics · Physics 2015-05-28 M. Schrinner

We use ensemble machine learning algorithms to study the evolution of magnetic fields in magnetohydrodynamic (MHD) turbulence that is helically forced. We perform direct numerical simulations of helically forced turbulence using mean field…

Solar and Stellar Astrophysics · Physics 2019-09-11 Farrukh Nauman , Joonas Nättilä

The macroscopic forcing method (MFM) of Mani and Park and similar methods for obtaining turbulence closure operators, such as the Green's function-based approach of Hamba, recover reduced solution operators from repeated direct numerical…

Computational Physics · Physics 2024-01-19 Spencer H. Bryngelson , Florian Schäfer , Jessie Liu , Ali Mani

A new generation of wide-field radio interferometers designed for 21-cm surveys is being built as drift scan instruments allowing them to observe large fractions of the sky. With large numbers of antennas and frequency channels the enormous…

Instrumentation and Methods for Astrophysics · Physics 2017-10-10 Philippe Berger , Niels Oppermann , Ue-Li Pen , J. Richard Shaw

Infinitesimal electric and magnetic dipoles are widely used as an equivalent radiating source model. In this paper, an improved method for dipole extraction from magnitude-only electromagnetic-field data based on genetic algorithm and…

Signal Processing · Electrical Eng. & Systems 2019-01-23 Chunyu Wu , Ze Sun , Xu Wang , Yansheng Wang , Ben Kim , Jun Fan

We present a fully automated framework for extracting interatomic force constants (IFCs) directly from X-ray thermal diffuse scattering (TDS) data. By formulating scattering intensity as a differentiable function of a symmetry-reduced IFC…

Computational Physics · Physics 2026-03-31 Klara Suchan , Shaswat Mohanty , Hanfeng Zhai , Wei Cai

Coherent magnetic fields in disc galaxies are thought to be generated by a large-scale (or mean-field) dynamo operating in their interstellar medium. A key driver of mean magnetic field growth is the turbulent electromotive force (EMF),…

Astrophysics of Galaxies · Physics 2020-01-08 Abhijit B. Bendre , Kandaswamy Subramanian , Detlef Elstner , Oliver Gressel

We present for the first time an efficient iterative method to directly solve the four-component Dirac-Kohn-Sham (DKS) density functional theory. Due to the existence of the negative energy continuum in the DKS operator, the existing…

Computational Physics · Physics 2013-05-03 Lin Lin , Sihong Shao , Weinan E

Image denoising is a fundamental challenge in computer vision, with applications in photography and medical imaging. While deep learning-based methods have shown remarkable success, their reliance on specific noise distributions limits…

Computer Vision and Pattern Recognition · Computer Science 2025-08-28 Dongjin Kim , Jaekyun Ko , Muhammad Kashif Ali , Tae Hyun Kim

The CLEAN algorithm, widely used in radio interferometry for the deconvolution of radio images, performs well only if the raw radio image (dirty image) is, to good approximation, a simple convolution between the instrumental point-spread…

Instrumentation and Methods for Astrophysics · Physics 2015-05-28 I. M. Stewart , D. M. Fenech , T. W. B. Muxlow

In this study we present a compressible test-field method (CTFM) for computing $\alpha$ effect and turbulent magnetic diffusivity tensors, as well as those relevant for mean ponderomotive force and mass source, applied to the full MHD…

Fluid Dynamics · Physics 2022-06-15 Maarit J. Käpylä , Matthias Rheinhardt , Axel Brandenburg

This work presents a cost-effective technique for designing robust adaptive beamforming algorithms based on efficient covariance matrix reconstruction with iterative spatial power spectrum (CMR-ISPS). The proposed CMR-ISPS approach…

Machine Learning · Computer Science 2023-09-06 S. Mohammadzadeh , V. H. Nascimento , R. C. de Lamare , O. Kukrer

Purpose: Point-of-care MRI requires operation outside of a faraday shielded room normally used to block image-degrading electromagnetic Interference (EMI). To address this, we introduce the EDITER method, an external sensor based dynamic…

Depth maps captured by modern depth cameras such as Kinect and Time-of-Flight (ToF) are usually contaminated by missing data, noises and suffer from being of low resolution. In this paper, we present a robust method for high-quality…

Computer Vision and Pattern Recognition · Computer Science 2015-12-29 Wei Liu , Yun Gu , Chunhua Shen , Xiaogang Chen , Qiang Wu , Jie Yang

We present a novel iterative algorithm for detection of binary Markov random fields (MRFs) corrupted by two-dimensional (2D) intersymbol interference (ISI) and additive white Gaussian noise (AWGN). We assume a first-order binary MRF as a…

Information Theory · Computer Science 2007-07-13 Ying Zhu , Taikun Cheng , Krishnamoorthy Sivakumar , Benjamin J. Belzer

Cloud removal (CR) remains a challenging task in remote sensing image processing. Although diffusion models (DM) exhibit strong generative capabilities, their direct applications to CR are suboptimal, as they generate cloudless images from…

Computer Vision and Pattern Recognition · Computer Science 2025-04-01 Yi Liu , Wengen Li , Jihong Guan , Shuigeng Zhou , Yichao Zhang

For single source helical Computed Tomography (CT), both Filtered-Back Projection (FBP) and statistical iterative reconstruction have been investigated. However for dual source CT with flying focal spot (DS-FFS CT), statistical iterative…

Image and Video Processing · Electrical Eng. & Systems 2022-02-14 Xiao Wang , Robert D. MacDougall , Peng Chen , Charles A. Bouman , Simon K. Warfield

The decomposition of a signal is a fundamental tool in many fields of research, including signal processing, geophysics, astrophysics, engineering, medicine, and many more. By breaking down complex signals into simpler oscillatory…

Numerical Analysis · Mathematics 2024-12-03 Roberto Cavassi , Antonio Cicone , Enza Pellegrino , Haomin Zhou
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