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Related papers: Insights into Quasar UV Spectra Using Unsupervised…

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We explore the extinction/reddening of ~35,000 uniformly selected quasars with 0<z<5.3 in order to better understand their intrinsic optical/ultraviolet spectral energy distributions. Using rest-frame optical-UV photometry taken from the…

Finding the number of meaningful clusters in an unlabeled dataset is important in many applications. Regularized k-means algorithm is a possible approach frequently used to find the correct number of distinct clusters in datasets. The most…

Machine Learning · Computer Science 2025-05-30 Behzad Kamgar-Parsi , Behrooz Kamgar-Parsi

The problem of unsupervised learning and segmentation of hyperspectral images is a significant challenge in remote sensing. The high dimensionality of hyperspectral data, presence of substantial noise, and overlap of classes all contribute…

Computer Vision and Pattern Recognition · Computer Science 2018-10-17 James M. Murphy , Mauro Maggioni

We present a catalog of 100,563 unresolved, UV-excess (UVX) quasar candidates to g=21 from 2099 deg^2 of the Sloan Digital Sky Survey (SDSS) Data Release One (DR1) imaging data. Existing spectra of 22,737 sources reveals that 22,191 (97.6%)…

Clustering is a critical component of decision-making in todays data-driven environments. It has been widely used in a variety of fields such as bioinformatics, social network analysis, and image processing. However, clustering accuracy…

Machine Learning · Computer Science 2025-07-14 Krishnendu Das , Sumit Gupta , Awadhesh Kumar

Clustering is an effective tool for astronomical spectral analysis, to mine clustering patterns among data. With the implementation of large sky surveys, many clustering methods have been applied to tackle spectroscopic and photometric data…

Instrumentation and Methods for Astrophysics · Physics 2022-12-19 Haifeng Yang , Chenhui Shi , Jianghui Cai , Lichan Zhou , Yuqing Yang , Xujun Zhao , Yanting He , Jing Hao

In computer vision, a prevailing method for quantifying dataset bias is to train a model to distinguish between datasets. High classification accuracy is then interpreted as evidence of meaningful semantic differences. This approach assumes…

Computer Vision and Pattern Recognition · Computer Science 2026-04-16 Amir Hossein Saleknia , Mohammad Sabokrou

Recent technological advances have led to a flood of new data on cosmology rich in information about the formation and evolution of the universe, e.g., the data collected in Sloan Digital Sky Survey (SDSS) for more than 200 million objects.…

Cosmology and Nongalactic Astrophysics · Physics 2009-02-25 Sabyasachi Mukhopadhyay , Sisir Roy , Sourabh Bhattacharya

Clustering performs an essential role in many real world applications, such as market research, pattern recognition, data analysis, and image processing. However, due to the high dimensionality of the input feature values, the data being…

Machine Learning · Computer Science 2021-02-16 Si Lu , Ruisi Li

This study explores the application of autoencoder-based machine learning techniques for anomaly detection to identify exoplanet atmospheres with unconventional chemical signatures using a low-dimensional data representation. We use the…

Earth and Planetary Astrophysics · Physics 2026-01-06 Alexander Roman , Emilie Panek , Roy T. Forestano , Eyup B. Unlu , Katia Matcheva , Konstantin T. Matchev

We give the first outlier-robust efficient algorithm for clustering a mixture of $k$ statistically separated d-dimensional Gaussians (k-GMMs). Concretely, our algorithm takes input an $\epsilon$-corrupted sample from a $k$-GMM and whp in…

Data Structures and Algorithms · Computer Science 2020-12-15 Ainesh Bakshi , Pravesh Kothari

In this paper, we consider clustering data that is assumed to come from one of finitely many pointed convex polyhedral cones. This model is referred to as the Union of Polyhedral Cones (UOPC) model. Similar to the Union of Subspaces (UOS)…

Machine Learning · Statistics 2017-11-03 Wenqi Wang , Vaneet Aggarwal , Shuchin Aeron

We consider the problem of simultaneously clustering and learning a linear representation of data lying close to a union of low-dimensional manifolds, a fundamental task in machine learning and computer vision. When the manifolds are…

Machine Learning · Computer Science 2023-08-25 Tianjiao Ding , Shengbang Tong , Kwan Ho Ryan Chan , Xili Dai , Yi Ma , Benjamin D. Haeffele

Microarrays are made it possible to simultaneously monitor the expression profiles of thousands of genes under various experimental conditions. Identification of co-expressed genes and coherent patterns is the central goal in microarray or…

Computational Engineering, Finance, and Science · Computer Science 2013-07-15 T. Chandrasekhar , K. Thangavel , E. Elayaraja , E. N. Sathishkumar

Bayesian nonparametrics are a class of probabilistic models in which the model size is inferred from data. A recently developed methodology in this field is small-variance asymptotic analysis, a mathematical technique for deriving learning…

Machine Learning · Statistics 2017-07-27 Trevor Campbell , Brian Kulis , Jonathan How

This paper demonstrates a novel and efficient unsupervised clustering method with the combination of a Self-Organising Map (SOM) and a convolutional autoencoder. The rapidly increasing volume of radio-astronomical data has increased demand…

Drawing the quantum phase diagram of a many-body system in the parameter space of its Hamiltonian can be seen as a learning problem, which implies labelling the corresponding ground states according to some classification criterium that…

Quantum Physics · Physics 2025-10-17 Mehran Khosrojerdi , Alessandro Cuccoli , Paola Verrucchi , Leonardo Banchi

In a standard cluster analysis, such as k-means, in addition to clusters locations and distances between them, it's important to know if they are connected or well separated from each other. The main focus of this paper is discovering the…

Machine Learning · Statistics 2017-05-22 Evgeny Bauman , Konstantin Bauman

We examine the three-dimensional clustering of C IV absorption-line systems, using an extensive catalog of QSO heavy-element absorbers drawn from the literature. We measure clustering by a volume-weighted integral of the correlation…

Astrophysics · Physics 2007-05-23 Ji Meng Loh , Jean M. Quashnock , Michael L. Stein

Statistical analysis of massive datasets very often implies expensive linear algebra operations with large dense matrices. Typical tasks are an estimation of unknown parameters of the underlying statistical model and prediction of missing…

Computation · Statistics 2021-04-16 Alexander Litvinenko , Ronald Kriemann , Vladimir Berikov
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