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In medical image segmentation, limited external validity remains a critical obstacle when models are deployed across unseen datasets, an issue particularly pronounced in the ultrasound image domain. Existing solutions-such as domain…

Image and Video Processing · Electrical Eng. & Systems 2025-05-30 Christian Schmidt , Heinrich Martin Overhoff

To test whether clusters have rising mass to light ratios at large radii and to estimate the amplitude of the density fluctuation spectrum on the scale of 10\hmpc\ the Canadian Network for Observational Cosmology (CNOC) cluster…

Astrophysics · Physics 2007-05-23 Carlberg

Identifying galaxy groups from redshift surveys of galaxies plays an important role in connecting galaxies with the underlying dark matter distribution. Current and future high-$z$ spectroscopic surveys, usually incomplete in redshift…

Astrophysics of Galaxies · Physics 2020-10-14 Kai Wang , H. J. Mo , Cheng Li , Jiacheng Meng , Yangyao Chen

Principal Component Analysis (PCA) is a ubiquitous tool with many applications in machine learning including feature construction, subspace embedding, and outlier detection. In this paper, we present an algorithm for computing the top…

Machine Learning · Computer Science 2013-10-25 Nikos Karampatziakis , Paul Mineiro

We have used HRCam on the CFHT to obtain subarcsecond images of 26 galaxies with z=0.1--0.7. The primary sample of 17 galaxies have enhanced star formation indicated by [OII] equivalent widths greater than 20\AA, while the comparison sample…

Astrophysics · Physics 2015-06-24 Matthew Colless , David Schade , T J Broadhurst , R S Ellis

We develop a photon energy measurement scheme for single photon counting Microwave Kinetic Inductance Detectors (MKIDs) that uses principal component analysis (PCA) to measure the energy of an incident photon from the signal ("photon…

Instrumentation and Methods for Astrophysics · Physics 2022-03-01 Jacob M. Miller , Nicholas Zobrist , Gerhard Ulbricht , Benjamin A. Mazin

A non-parametric smoothing method is presented that reduces noise in multi-wavelength imaging data sets. Using Principle Component Analysis (hereafter PCA) to associate pixels according to their $ugriz$-band colors, smoothing is done over…

Instrumentation and Methods for Astrophysics · Physics 2015-03-17 James Pizagno

This paper presents a comprehensive study of quasar photometric classification and redshift estimation using machine learning techniques. We cross-matched photometric data from the Dark Energy Survey Data Release 2 (DES DR2) with…

Instrumentation and Methods for Astrophysics · Physics 2026-05-19 Pablo Motta , Filipe B. Abdalla , Elcio Abdalla , Gabriel S. Costa , Camila Cardoso

A simple estimate of the photometric redshift would prove invaluable to forthcoming continuum surveys on the next generation of large radio telescopes, as well as mitigating the existing bias towards the most optically bright sources. While…

Astrophysics of Galaxies · Physics 2019-09-11 S. J. Curran , J. P. Moss

The 15R-North galaxy redshift survey is a uniform spectroscopic survey (S/N $\sim $10) covering the range 3650---7400\AA for 3149 galaxies with median redshift 0.05. The sample is 90% complete to $R=15.4$. The median slit covering fraction…

Astrophysics · Physics 2009-11-06 B. J. Carter , D. G. Fabricant , M. J. Geller , M. J. Kurtz

Based on the Sloan Digital Sky Survey Data Release 5 Galaxy Sample, we explore photometric morphology classification and redshift estimation of galaxies using photometric data and known spectroscopic redshifts. An unsupervised method,…

Astrophysics · Physics 2009-11-13 Yanxia Zhang , Lili Li , Yongheng Zhao

Terahertz (THz) systems inherently introduce frequency-dependent degradation effects, resulting in low-frequency blurring and high-frequency noise in amplitude images. Conventional image processing techniques cannot simultaneously address…

Computer Vision and Pattern Recognition · Computer Science 2026-02-25 Pengfei Zhu , Stefano Sfarra , Hai Zhang , Carlo Santulli , Elana Pivarciova , Fabrizio Sarasini , Xavier Maldague

We introduce a novel galaxy classification methodology based on the visible spectra of a sample of over 68,000 nearby ($z\leq 0.1$) Sloan Digital Sky Survey lenticular (S0) galaxies. Unlike traditional diagnostic diagrams, which rely on a…

Astrophysics of Galaxies · Physics 2025-01-10 J. L. Tous , J. M. Solanes , J. D. Perea

Determination of cosmological parameters is a major goal in cosmology at present. The availability of improved data sets necessitates the development of novel statistical tools to interpret the inference from a cosmological model. In this…

Cosmology and Nongalactic Astrophysics · Physics 2024-09-04 Ranbir Sharma , H K Jassal

Principal Component Analysis (PCA) is a classical method for reducing the dimensionality of data by projecting them onto a subspace that captures most of their variation. Effective use of PCA in modern applications requires understanding…

Statistics Theory · Mathematics 2019-06-14 David Hong , Laura Balzano , Jeffrey A. Fessler

We demonstrate that Principal Component Analysis (PCA), when applied in a structured manner, either to polar-transformed images or segment-wise to token sequences, enables extreme compression of neural models without sacrificing…

Computational Engineering, Finance, and Science · Computer Science 2025-08-07 Magnus Bengtsson

We analyse a sample of 26 active galactic nuclei with deep XMM-Newton observations, using principal component analysis (PCA) to find model independent spectra of the different variable components. In total, we identify at least 12…

High Energy Astrophysical Phenomena · Physics 2015-06-23 M. L. Parker , A. C. Fabian , G. Matt , K. I. I. Koljonen , E. Kara , W. Alston , D. J. Walton , A. Marinucci , L. Brenneman , G. Risaliti

Principal Component Analysis (PCA) is a fundamental tool for data visualization, denoising, and dimensionality reduction. It is widely popular in Statistics, Machine Learning, Computer Vision, and related fields. However, PCA is well-known…

Machine Learning · Statistics 2023-07-21 Debolina Paul , Saptarshi Chakraborty , Swagatam Das

The identification of high-redshift quasars ($z > 4.5$) is critical for studying the early Universe, supermassive black hole growth, and cosmic reionization. Most known high-redshift quasars are located in the northern hemisphere, leaving…

The upcoming imaging survey of the Chinese Space-station Survey Telescope (CSST) will deliver high-resolution imaging of an unprecedented number of galaxies for galaxy studies. To understand CSST's capability, and to support the preparation…

Astrophysics of Galaxies · Physics 2026-04-28 Ziqi Ma , Si-Yue Yu , Taotao Fang , Jinyi Shangguan , Zhao-Yu Li , Luis C. Ho
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