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Related papers: Issues with time--distance inversions for supergra…

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Inverse medium scattering solvers generally reconstruct a single solution without an associated measure of uncertainty. This is true both for the classical iterative solvers and for the emerging deep learning methods. But ill-posedness and…

Machine Learning · Computer Science 2022-12-12 AmirEhsan Khorashadizadeh , Ali Aghababaei , Tin Vlašić , Hieu Nguyen , Ivan Dokmanić

Recently, Duvall and Hanasoge ({\it Solar Phys.} {\bf 287}, 71-83, 2013) found that large distance $[\Delta]$ separation travel-time differences from a center to an annulus $[\delta t_{\rm{oi}}]$ implied a model of the average supergranular…

Solar and Stellar Astrophysics · Physics 2015-06-19 T. L. Duvall , S. M. Hanasoge , S. Chakraborty

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

Here we use synthetic data to explore the performance of forward models and inverse methods for helioseismic holography. Specifically, this work presents the first comprehensive test of inverse modeling for flows using lateral-vantage…

Solar and Stellar Astrophysics · Physics 2018-08-15 K. DeGrave , D. C. Braun , A. C. Birch , A. D. Crouch , B. Javornik

Due to its speed after training, machine learning is often envisaged as a solution to a manifold of the issues faced in gravitational-wave astronomy. Demonstrations have been given for various applications in gravitational-wave data…

General Relativity and Quantum Cosmology · Physics 2023-05-10 Jurriaan Langendorff , Alex Kolmus , Justin Janquart , Chris Van Den Broeck

Granular simulations are used to probe the particle scale dynamics at short, intermediate, and long time scales for gravity driven, dense granular flows down an inclined plane. On approach to the angle of repose, where motion ceases, the…

Soft Condensed Matter · Physics 2009-11-11 L. E. Silbert

An algorithm is proposed for generalized mean curvature flow of closed two-dimensional surfaces, which include inverse mean curvature flow, powers of mean and inverse mean curvature flow, etc. Error estimates are proven for semi- and full…

Numerical Analysis · Mathematics 2021-03-16 Tim Binz , Balázs Kovács

Flow-based generative modeling is a powerful tool for solving inverse problems in physical sciences that can be used for sampling and likelihood evaluation with much lower inference times than traditional methods. We propose to refine flows…

Machine Learning · Computer Science 2024-10-31 Benjamin Holzschuh , Nils Thuerey

We present a new, variational, fully nonlinear, probabilistic ambient noise tomography method, which estimates subsurface structure and quantifies the corresponding uncertainties directly in three dimensions (3D) from inter-receiver seismic…

Geophysics · Physics 2026-01-13 Xuebin Zhao , Lily Irvin , Erica Galetti , Andrew Curtis

Non-Gaussian noise in gravitational-wave detectors, known as "glitches," can bias the inferred parameters of transient signals when they occur nearby in time and frequency. These biases are addressed with a variety of methods that remove or…

General Relativity and Quantum Cosmology · Physics 2025-10-07 Sophie Hourihane , Katerina Chatziioannou

Diffusion models (DMs) are a powerful generative framework that have attracted significant attention in recent years. However, the high computational cost of training DMs limits their practical applications. In this paper, we start with a…

Machine Learning · Computer Science 2024-04-12 Tianshuo Xu , Peng Mi , Ruilin Wang , Yingcong Chen

If $\gamma$-ray bursts are at cosmological distances, then not only their constituent pulses but also the intervals between pulses should be time-dilated. Unlike time-dilation measures of pulse emission, intervals would appear to require…

Astrophysics · Physics 2009-10-28 J. P. Norris , J. T. Bonnell , R. J. Nemiroff , J. D. Scargle

A space-time interface-fitted approximation of an inverse source problem for the advection-diffusion equation with moving subdomains is investigated. The problem is reformulated as an optimization problem using Tikhonov regularization. A…

Numerical Analysis · Mathematics 2025-02-11 Thi Thanh Mai Ta , Quang Huy Nguyen , Dinh Nho Hào

The diffusion-driven Turing instability is a potential mechanism for spatial pattern formation in numerous biological and chemical systems. However, engineering these patterns and demonstrating that they are produced by this mechanism is…

Biological Physics · Physics 2025-12-02 Antonio Matas-Gil , Robert G. Endres

The possibility to have results very quickly after, or even during, the collection of electromagnetic data would be important, not only for quality check purposes, but also for adjusting the location of the proposed flight lines during an…

Geophysics · Physics 2020-11-09 Peng Bai , Giulio Vignoli , Andrea Viezzoli , Jouni Nevalainen , Giuseppina Vacca

Time--distance inversions usually provide tomographic maps of the interesting plasma properties (we will focus on flows) at various depths. These maps however do not correspond directly to the flow field, but rather to the true flow field…

Solar and Stellar Astrophysics · Physics 2017-04-12 M. Svanda , M. Kozon

Frequency-domain electromagnetic instruments allow the collection of data in different configurations, that is, varying the intercoil spacing, the frequency, and the height above the ground. Their handy size makes these tools very practical…

Numerical Analysis · Mathematics 2021-09-21 Gian Piero Deidda , Patricia Diaz de Alba , Giuseppe Rodriguez , Giulio Vignoli

According to time-distance helioseismology, information about internal fluid motions is encoded in the travel times of solar waves. The inverse problem consists of inferring 3-D vector flows from a set of travel-time measurements. Here we…

Solar and Stellar Astrophysics · Physics 2015-05-27 M. Svanda , L. Gizon , S. M. Hanasoge , S. D. Ustyugov

This paper is concerned with the inverse obstacle scattering problem with phaseless far-field data at a fixed frequency. The main difficulty of this problem is the so-called translation invariance property of the modulus of the far-field…

Numerical Analysis · Mathematics 2018-08-29 Bo Zhang , Haiwen Zhang

The problem of inverse statistics (statistics of distances for which the signal fluctuations are larger than a certain threshold) in differentiable signals with power law spectrum, $E(k) \sim k^{-\alpha}$, $3 \le \alpha < 5$, is discussed.…

Chaotic Dynamics · Physics 2009-11-07 L. Biferale , M. Cencini , A. Lanotte , D. Vergni , A. Vulpiani