English
Related papers

Related papers: Improved supervised learning methods for EoR param…

200 papers

In this study, we train score-based diffusion models to super-resolve gigaparsec-scale cosmological simulations of the 21-cm signal. We examine the impact of network and training dataset size on model performance, demonstrating that a…

Cosmology and Nongalactic Astrophysics · Physics 2025-02-04 Simon Pochinda , Jiten Dhandha , Anastasia Fialkov , Eloy de Lera Acedo

With the inspiration of vision transformers, the concept of depth-wise convolution revisits to provide a large Effective Receptive Field (ERF) using Large Kernel (LK) sizes for medical image segmentation. However, the segmentation…

Image and Video Processing · Electrical Eng. & Systems 2023-06-07 Ho Hin Lee , Quan Liu , Shunxing Bao , Qi Yang , Xin Yu , Leon Y. Cai , Thomas Li , Yuankai Huo , Xenofon Koutsoukos , Bennett A. Landman

Learning-based approaches have witnessed great successes in blind single image super-resolution (SISR) tasks, however, handcrafted kernel priors and learning based kernel priors are typically required. In this paper, we propose a…

Image and Video Processing · Electrical Eng. & Systems 2024-06-14 Jingyuan Xia , Zhixiong Yang , Shengxi Li , Shuanghui Zhang , Yaowen Fu , Deniz Gündüz , Xiang Li

The cosmic 21-cm signal will bring data-driven advances to studies of the Cosmic Dawn (CD) and Epoch of Reionization (EoR). Radio telescopes such as the SKA will eventually map the HI fluctuations over the first billion years - the majority…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-08 David Prelogović , Andrei Mesinger

The lunar Askaryan technique is a method to study the highest-energy cosmic rays, and their predicted counterparts, the ultra-high-energy neutrinos. By observing the Moon with a radio telescope, and searching for the characteristic…

We study generalization properties of distributed algorithms in the setting of nonparametric regression over a reproducing kernel Hilbert space (RKHS). We first investigate distributed stochastic gradient methods (SGM), with mini-batches…

Machine Learning · Statistics 2018-11-06 Junhong Lin , Volkan Cevher

We investigate systematic effects in direction dependent gain calibration in the context of the Low-Frequency Array (LOFAR) 21-cm Epoch of Reionization (EoR) experiment. The LOFAR EoR Key Science Project aims to detect the 21-cm signal of…

Recently, many self-supervised learning methods for image reconstruction have been proposed that can learn from noisy data alone, bypassing the need for ground-truth references. Most existing methods cluster around two classes: i) Stein's…

Machine Learning · Statistics 2025-02-12 Julián Tachella , Mike Davies , Laurent Jacques

Kernel ridge regression, KRR, is a generalization of linear ridge regression that is non-linear in the data, but linear in the model parameters. Here, we introduce an equivalent formulation of the objective function of KRR, which opens up…

Machine Learning · Statistics 2025-03-10 Oskar Allerbo

We present new upper limits on the 21-cm signal power spectrum from the Epoch of Reionization (EoR), at redshifts $z \approx 10.1, 9.1, \text{ and } 8.3$, based on reprocessed observations from the Low-Frequency Array (LOFAR). The analysis…

The cosmological case for a next generation radio observatory, the Square Kilometer Array, is discussed and reviewed. An instrument like the SKA would be able to measure galaxy redshifts of normal late-type galaxies, via the 21 cm line of…

Astrophysics · Physics 2007-05-23 Rien van de Weygaert , Tjeerd S. van Albada

Previous methods decompose the blind super-resolution (SR) problem into two sequential steps: \textit{i}) estimating the blur kernel from given low-resolution (LR) image and \textit{ii}) restoring the SR image based on the estimated kernel.…

Computer Vision and Pattern Recognition · Computer Science 2021-05-17 Zhengxiong Luo , Yan Huang , Shang Li , Liang Wang , Tieniu Tan

The extremely high sensitivity and resolution of the Square Kilometre Array (SKA) will be useful for addressing a wide set of themes relevant for cosmology, in synergy with current and future cosmic microwave background (CMB) projects. Many…

21cm tomography opens a window to directly study astrophysics and fundamental physics of early epochs in our Universe's history, the Epoch of Reionisation (EoR) and Cosmic Dawn (CD). Summary statistics such as the power spectrum omit…

Cosmology and Nongalactic Astrophysics · Physics 2022-02-09 S. Neutsch , C. Heneka , M. Brüggen

We study the impact of instrumental systematics on the variance, skewness, and kurtosis of redshifted 21 cm intensity fluctuation observations from the Epoch of Reionization. We simulate realistic 21 cm observations based on the Murchison…

Cosmology and Nongalactic Astrophysics · Physics 2016-10-20 Piyanat Kittiwisit , Judd D. Bowman , Daniel C. Jacobs , Nithyanandan Thyagarajan , Adam P. Beardsley

Imaging the cosmic 21 cm signal will map out the first billion years of our Universe. The resulting 3D lightcone (LC) will encode the properties of the unseen first galaxies and physical cosmology. Here, we build on previous work using…

Cosmology and Nongalactic Astrophysics · Physics 2022-02-17 David Prelogović , Andrei Mesinger , Steven Murray , Giuseppe Fiameni , Nicolas Gillet

At present, the Synthetic Aperture Radar (SAR) image classification method based on convolution neural network (CNN) has faced some problems such as poor noise resistance and generalization ability. Spiking neural network (SNN) is one of…

Computer Vision and Pattern Recognition · Computer Science 2021-06-16 Jiankun Chen , Xiaolan Qiu , Chibiao Ding , Yirong Wu

Optimizing k-space sampling trajectories is a promising yet challenging topic for fast magnetic resonance imaging (MRI). This work proposes to optimize a reconstruction method and sampling trajectories jointly concerning image…

Signal Processing · Electrical Eng. & Systems 2022-04-15 Guanhua Wang , Tianrui Luo , Jon-Fredrik Nielsen , Douglas C. Noll , Jeffrey A. Fessler

The Square Kilometre Array (SKA), currently under design, will be a transformational facility for studying the Universe at centimetre and metre wavelengths in the next decade and beyond. This paper provides the current best estimate of the…

Instrumentation and Methods for Astrophysics · Physics 2020-01-01 Robert Braun , Anna Bonaldi , Tyler Bourke , Evan Keane , Jeff Wagg

Next-generation radio interferometers, such as the Square Kilometre Array (SKA), will revolutionise our understanding of the universe through their unprecedented sensitivity and resolution. However, to realise these goals significant…

Instrumentation and Methods for Astrophysics · Physics 2017-11-20 Luke Pratley , Jason D. McEwen , Mayeul d'Avezac , Rafael E. Carrillo , Alexandru Onose , Yves Wiaux
‹ Prev 1 8 9 10 Next ›