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We investigate simulation-based bandpower covariance matrices commonly used in cosmological parameter inferences such as the estimation of the tensor-to-scalar ratio $r$. We find that upper limits on $r$ can be biased low by tens of…

Cosmology and Nongalactic Astrophysics · Physics 2022-07-06 Dominic Beck , Ari Cukierman , W. L. Kimmy Wu

Recent deep learning-based image denoising methods have shown impressive performance; however, many lack the flexibility to adjust the denoising strength based on the noise levels, camera settings, and user preferences. In this paper, we…

Computer Vision and Pattern Recognition · Computer Science 2025-09-05 Youngjin Oh , Junhyeong Kwon , Keuntek Lee , Nam Ik Cho

Next-generation particle accelerators demand advanced beam-diagnostic capabilities to ensure high performance, operational reliability, and sustainable machine operation. Increasing beam intensities and stored energies make the precise…

Accelerator Physics · Physics 2026-03-10 Francis René Osswald , Mohammed Chahbaoui , Xinyi Liang

We trained denoiser autoencoding neural networks on medium resolution simulated optical spectra of late-type stars to demonstrate that the reconstruction of the original flux is possible at a typical relative error of a fraction of a…

Instrumentation and Methods for Astrophysics · Physics 2024-09-19 Balázs Pál , László Dobos

In this manuscript we consider denoising of large rectangular matrices: given a noisy observation of a signal matrix, what is the best way of recovering the signal matrix itself? For Gaussian noise and rotationally-invariant signal priors,…

Disordered Systems and Neural Networks · Physics 2022-10-03 Emanuele Troiani , Vittorio Erba , Florent Krzakala , Antoine Maillard , Lenka Zdeborová

The increase in the observed volume in cosmological surveys imposes various challenges on simulation preparations. Firstly, the volume of the simulations required increases proportionally to the observations. However, large-volume…

Cosmology and Nongalactic Astrophysics · Physics 2022-06-01 Daniel Forero-Sánchez , Chia-Hsun Chuang , Sergio Rodríguez-Torres , Gustavo Yepes , Stefan Gottlöber , Cheng Zhao

In the near future, observations of the cosmic microwave background (CMB) anisotropies will provide accurate determinations of many fundamental cosmological parameters. In this paper, we analyse degeneracies among cosmological parameters to…

Astrophysics · Physics 2009-10-30 G. Efstathiou , J. R. Bond

Deep neural networks have proven extremely efficient at solving a wide rangeof inverse problems, but most often the uncertainty on the solution they provideis hard to quantify. In this work, we propose a generic Bayesian framework…

Machine Learning · Statistics 2020-11-18 Zaccharie Ramzi , Benjamin Remy , Francois Lanusse , Jean-Luc Starck , Philippe Ciuciu

This paper revisits the problem of decomposing a positive semidefinite matrix as a sum of a matrix with a given rank plus a sparse matrix. An immediate application can be found in portfolio optimization, when the matrix to be decomposed is…

Optimization and Control · Mathematics 2021-06-16 Michel Baes , Calypso Herrera , Ariel Neufeld , Pierre Ruyssen

How many simulations do we need to train machine learning methods to extract information available from summary statistics of the cosmological density field? Neural methods have shown the potential to extract non-linear information…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-26 Anirban Bairagi , Benjamin Wandelt , Francisco Villaescusa-Navarro

Future galaxy surveys will provide accurate measurements of the matter power spectrum across an unprecedented range of scales and redshifts. The analysis of these data will require one to accurately model the imprint of non-linearities of…

Cosmology and Nongalactic Astrophysics · Physics 2020-11-11 Linda Blot , Pier-Stefano Corasaniti , Yann Rasera , Shankar Agarwal

The denoising of magnetic resonance (MR) images is a task of great importance for improving the acquired image quality. Many methods have been proposed in the literature to retrieve noise free images with good performances. Howerever, the…

Computer Vision and Pattern Recognition · Computer Science 2018-02-01 Dongsheng Jiang , Weiqiang Dou , Luc Vosters , Xiayu Xu , Yue Sun , Tao Tan

Deep learning is a powerful analysis technique that has recently been proposed as a method to constrain cosmological parameters from weak lensing mass maps. Due to its ability to learn relevant features from the data, it is able to extract…

Cosmology and Nongalactic Astrophysics · Physics 2018-12-26 Janis Fluri , Tomasz Kacprzak , Aurelien Lucchi , Alexandre Refregier , Adam Amara , Thomas Hofmann

Cosmological large-scale structure analyses based on two-point correlation functions often assume a Gaussian likelihood function with a fixed covariance matrix. We study the impact on cosmological parameter estimation of ignoring the…

Cosmology and Nongalactic Astrophysics · Physics 2019-03-21 Darsh Kodwani , David Alonso , Pedro Ferreira

Weak gravitational lensing is a powerful probe of cosmology, with second-order shear statistics commonly used to constrain parameters such as the matter density $\Omega_\mathrm{m}$ and the clustering amplitude $S_8$. However, parameter…

Cosmology and Nongalactic Astrophysics · Physics 2025-09-26 Niek Wielders , Laila Linke , Pierre A. Burger , Sven Heydenreich , Lucas Porth , Peter Schneider

Accurate covariance matrices are required for a reliable estimation of cosmological parameters from pseudo-power spectrum estimators. In this work, we focus on the analytical calculation of covariance matrices. We consider the case of…

Cosmology and Nongalactic Astrophysics · Physics 2022-12-08 Étienne Camphuis , Karim Benabed , Silvia Galli , Éric Hivon , Marc Lilley

The ability to obtain reliable point estimates of model parameters is of crucial importance in many fields of physics. This is often a difficult task given that the observed data can have a very high number of dimensions. In order to…

Cosmology and Nongalactic Astrophysics · Physics 2021-12-15 Janis Fluri , Aurelien Lucchi , Tomasz Kacprzak , Alexandre Refregier , Thomas Hofmann

Removing the shape noise from the observed weak lensing field, i.e., denoising, enhances the potential of WL by accessing information at small scales where the shape noise dominates without denoising. We utilise two machine learning (ML)…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-13 Shohei D. Aoyama , Ken Osato , Masato Shirasaki

In machine learning approach to image denoising a network is trained to recover a clean image from a noisy one. In this paper a novel structure is proposed based on training multiple specialized networks as opposed to existing structures…

Image and Video Processing · Electrical Eng. & Systems 2020-12-01 Seyed Mohsen Hosseini

We apply a novel method with machine learning to calibrate sub-grid models within numerical simulation codes to achieve convergence with observations and between different codes. It utilizes active learning and neural density estimators.…

Astrophysics of Galaxies · Physics 2022-10-07 Boon Kiat Oh , Hongjun An , Eun-jin Shin , Ji-hoon Kim , Sungwook E. Hong
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