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Principal component analysis (PCA) aims at estimating the direction of maximal variability of a high-dimensional dataset. A natural question is: does this task become easier, and estimation more accurate, when we exploit additional…

Information Theory · Computer Science 2014-06-19 Andrea Montanari , Emile Richard

We use state-of-the-art radiation-MHD simulations and 3D non-LTE radiative transfer computations to investigate \Halpha\ line formation in the solar chromosphere and apply the results of this investigation to develop the potential of…

Solar and Stellar Astrophysics · Physics 2015-06-04 Jorrit Leenaarts , Mats Carlsson , Luc Rouppe van der Voort

Solar photovoltaic (PV) modules are prone to damage during manufacturing, installation and operation which reduces their power conversion efficiency. This diminishes their positive environmental impact over the lifecycle. Continuous…

Computer Vision and Pattern Recognition · Computer Science 2025-08-04 Swayam Rajat Mohanty , Moin Uddin Maruf , Vaibhav Singh , Zeeshan Ahmad

We describe a global parametric model for the observed power spectra of solar oscillations of intermediate and low degree. A physically motivated parameterization is used as a substitute for a direct description of mode excitation and…

Solar and Stellar Astrophysics · Physics 2015-06-17 Sergei V. Vorontsov , Stuart M. Jefferies

We aim to better understand how the spatial structure of molecular clouds is governed by turbulence. For that, we study the large-scale spatial distribution of low density molecular gas and search for characteristic length scales. We employ…

Astrophysics of Galaxies · Physics 2015-05-18 N. Schneider , S. Bontemps , R. Simon , V. Ossenkopf , C. Federrath , R. Klessen , F. Motte , P. Andre , J. Stutzki , C. Brunt

Strong lensing in galaxy clusters probes properties of dense cores of dark matter halos in mass, studies the distant universe at flux levels and spatial resolutions otherwise unavailable, and constrains cosmological models independently.…

Instrumentation and Methods for Astrophysics · Physics 2023-01-04 Peng Jia , Ruiqi Sun , Nan Li , Yu Song , Runyu Ning , Hongyan Wei , Rui Luo

Extracting information from complex data is a challenge shared by multiple frontiers of modern astrophysical research. Among those, analyzing spectra cubes, where the emission is mapped in the position-position-velocity space is a difficult…

Instrumentation and Methods for Astrophysics · Physics 2024-10-21 Zhenzhen He , Guang-Xing Li

Clouds frequently cover the Earth's surface and pose an omnipresent challenge to optical Earth observation methods. The vast majority of remote sensing approaches either selectively choose single cloud-free observations or employ a…

Computer Vision and Pattern Recognition · Computer Science 2018-12-04 Marc Rußwurm , Marco Körner

Topological data analysis (TDA) is a rapidly developing collection of methods for studying the shape of point cloud and other data types. One popular approach, designed to be robust to noise and outliers, is to first use a smoothing…

Methodology · Statistics 2017-12-27 Chul Moon , Noah Giansiracusa , Nicole A. Lazar

We perform a principal component analysis (PCA) of two one-dimensional lattice models belonging to distinct nonequilibrium universality classes - directed bond percolation and branching and annihilating random walks with even number of…

Cellular Automata are discrete dynamical systems that evolve following simple and local rules. Despite of its local simplicity, knowledge discovery in CA is a NP problem. This is the main motivation for using data mining techniques for CA…

Discrete Mathematics · Computer Science 2007-05-23 Gilson A. Giraldi , Antonio A. F. Oliveira , Leonardo Carvalho

We explore the diagnostic potential of the H$\alpha$ line for probing the chromospheric magnetic field using a realistic 3D radiative magnetohydrodynamic (rMHD) model. The Stokes profiles of the H$\alpha$ line are synthesized through full…

Solar and Stellar Astrophysics · Physics 2025-07-08 Harsh Mathur , Jayant Joshi , Thore Espedal Moe , Tiago M. D. Pereira , K. Nagaraju

Ground-based observations at thermal infrared wavelengths suffer from large background radiation due to the sky, telescope and warm surfaces in the instrument. This significantly limits the sensitivity of ground-based observations at…

Instrumentation and Methods for Astrophysics · Physics 2018-03-16 Silvan Hunziker , Sascha P. Quanz , Adam Amara , Michael R. Meyer

Principal component analysis (PCA) is often used for analyzing data in the most diverse areas. In this work, we report an integrated approach to several theoretical and practical aspects of PCA. We start by providing, in an intuitive and…

Computational Engineering, Finance, and Science · Computer Science 2021-06-09 Felipe L. Gewers , Gustavo R. Ferreira , Henrique F. de Arruda , Filipi N. Silva , Cesar H. Comin , Diego R. Amancio , Luciano da F. Costa

The cold neutral medium (CNM) is where neutral atomic hydrogen (HI) is converted into molecular clouds, so the structure and kinematics of the CNM are key drivers of galaxy evolution. Here we provide new constraints on the vertical…

Astrophysics of Galaxies · Physics 2024-09-30 Daniel R. Rybarczyk , Trey V. Wenger , Snezana Stanimirović

Principal Component Analysis (PCA) is an important tool of dimension reduction especially when the dimension (or the number of variables) is very high. Asymptotic studies where the sample size is fixed, and the dimension grows [i.e., High…

Statistics Theory · Mathematics 2009-11-20 Sungkyu Jung , J. S. Marron

Accurate cloud property retrieval is vital for understanding cloud behavior and its impact on climate, including applications in weather forecasting, climate modeling, and estimating Earth's radiation balance. The Independent Pixel…

Computer Vision and Pattern Recognition · Computer Science 2025-04-10 Zahid Hassan Tushar , Adeleke Ademakinwa , Jianwu Wang , Zhibo Zhang , Sanjay Purushotham

The Helioseismic and Magnetic Imager (HMI) has just started producing data that will help determine what the sources and mechanisms of variability in the Sun's interior are. The instrument measures the Doppler shift and the polarization of…

Solar and Stellar Astrophysics · Physics 2010-12-20 Rebecca Centeno , Steve Tomczyk , Juan Manuel Borrero , Sebastien Couvidat , Keiji Hayashi , Todd Hoeksema , Yang Liu , Jesper Schou

Big data is transforming our world, revolutionizing operations and analytics everywhere, from financial engineering to biomedical sciences. The complexity of big data often makes dimension reduction techniques necessary before conducting…

Methodology · Statistics 2018-01-08 Jianqing Fan , Qiang Sun , Wen-Xin Zhou , Ziwei Zhu

Feature extraction and dimensionality reduction are important tasks in many fields of science dealing with signal processing and analysis. The relevance of these techniques is increasing as current sensory devices are developed with ever…

Machine Learning · Statistics 2013-10-21 Jerónimo Arenas-García , Kaare Brandt Petersen , Gustavo Camps-Valls , Lars Kai Hansen