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Bursts of images exhibit significant self-similarity across both time and space. This motivates a representation of the kernels as linear combinations of a small set of basis elements. To this end, we introduce a novel basis prediction…

Computer Vision and Pattern Recognition · Computer Science 2020-12-04 Zhihao Xia , Federico Perazzi , Michaël Gharbi , Kalyan Sunkavalli , Ayan Chakrabarti

While Gamma-Ray Burst (GRBs) are clear and distinct observed events, every individual GRB is unique. In fact, GRBs are known for their variable behaviour, and BATSE was already able to discover two categories of GRB from the T90…

High Energy Astrophysical Phenomena · Physics 2023-08-25 Karlijn Kruiswijk , Gwenhaël de Wasseige

Searching for as yet undetected gamma-ray sources is a major target of the Fermi LAT Collaboration. We present an algorithm capable of identifying such type of sources by non-parametrically clustering the directions of arrival of the…

Instrumentation and Methods for Astrophysics · Physics 2023-01-30 Anna Montin , Alessandra R. Brazzale , Giovanna Menardi

In this paper, we propose and study a Nystr\"om based approach to efficient large scale kernel principal component analysis (PCA). The latter is a natural nonlinear extension of classical PCA based on considering a nonlinear feature map or…

Machine Learning · Statistics 2019-07-12 Nicholas Sterge , Bharath Sriperumbudur , Lorenzo Rosasco , Alessandro Rudi

Gamma-ray bursts provide what is probably one of the messiest of all astrophysical data sets. Burst class properties are indistinct, as overlapping characteristics of individual bursts are convolved with effects of instrumental and sampling…

In this chapter we review the main literature related to kernel spectral clustering (KSC), an approach to clustering cast within a kernel-based optimization setting. KSC represents a least-squares support vector machine based formulation of…

Machine Learning · Computer Science 2015-05-05 Rocco Langone , Raghvendra Mall , Carlos Alzate , Johan A. K. Suykens

We use gas-dynamical simulations of galaxy clusters to compare their X-ray and strong lensing properties. Special emphasis is laid on mass estimates. The cluster masses range between 6 x 10^14 solar masses and 4 x 10^15 solar masses, and…

Astrophysics · Physics 2015-06-24 Matthias Bartelmann , Matthias Steinmetz

Partially recorded data are frequently encountered in many applications and usually clustered by first removing incomplete cases or features with missing values, or by imputing missing values, followed by application of a clustering…

Methodology · Statistics 2021-10-20 Emily M. Goren , Ranjan Maitra

We evaluate the misclustering probability of a spectral clustering algorithm under a Gaussian mixture model with a general covariance structure. The algorithm partitions the data into two groups based on the sign of the first principal…

Statistics Theory · Mathematics 2026-04-13 Kohei Kawamoto , Yuichi Goto , Koji Tsukuda

To cluster data that are not linearly separable in the original feature space, $k$-means clustering was extended to the kernel version. However, the performance of kernel $k$-means clustering largely depends on the choice of kernel…

Machine Learning · Computer Science 2018-11-02 Yaqiang Yao , Huanhuan Chen

The three gamma-ray burst (GRB) classes identified by statistical clustering analysis (Mukherjee et al. 1998) are examined using the pattern recognition algorithm C4.5 (Quinlan 1986). Although the statistical existence of Class 3…

The search for gamma radiation in clusters of galaxies represents a precious tool to investigate the history of these large scale structures. Clusters or sources within them accelerate cosmic rays, as demonstrated by the detection of radio…

Astrophysics · Physics 2007-05-23 Pasquale Blasi

In this paper, we revisit the problem of clustering 1318 new variable stars found in the Milky way. Our recent work distinguishes these stars based on their light curves which are univariate series of brightness from the stars observed at…

Applications · Statistics 2022-02-23 Soumita Modak , Tanuka Chattopadhyay , Asis Kumar Chattopadhyay

We propose a spectral clustering method based on local principal components analysis (PCA). After performing local PCA in selected neighborhoods, the algorithm builds a nearest neighbor graph weighted according to a discrepancy between the…

Machine Learning · Statistics 2019-04-09 Ery Arias-Castro , Gilad Lerman , Teng Zhang

Clustering is a widely used unsupervised learning method for finding structure in the data. However, the resulting clusters are typically presented without any guarantees on their robustness; slightly changing the used data sample or…

Machine Learning · Statistics 2017-01-02 Andreas Henelius , Kai Puolamäki , Henrik Boström , Panagiotis Papapetrou

Personalized treatment of patients based on tissue-specific cancer subtypes has strongly increased the efficacy of the chosen therapies. Even though the amount of data measured for cancer patients has increased over the last years, most…

Machine Learning · Statistics 2017-09-18 Nora K. Speicher , Nico Pfeifer

Multiple datasets containing different types of features may be available for a given task. For instance, users' profiles can be used to group users for recommendation systems. In addition, a model can also use users' historical behaviors…

Machine Learning · Computer Science 2016-05-10 Weixiang Shao , Xiaoxiao Shi , Philip S. Yu

Two different multivariate clustering techniques, the K-means partitioning method and the Dirichlet process of mixture modeling, have been applied to the BATSE Gamma-ray burst (GRB) catalog, to obtain the optimum number of coherent groups.…

Astrophysics · Physics 2010-06-22 Tanuka Chattopadhyay , Ranjeev Misra , Asis Kumar Chattopadhyay , Malay Naskar

The use of kernel functions is a common technique to extract important features from data sets. A quantum computer can be used to estimate kernel entries as transition amplitudes of unitary circuits. Quantum kernels exist that, subject to…

Despite the ubiquity of kernel-based clustering, surprisingly few statistical guarantees exist beyond settings that consider strong structural assumptions on the data generation process. In this work, we take a step towards bridging this…

Machine Learning · Computer Science 2021-10-19 Leena Chennuru Vankadara , Sebastian Bordt , Ulrike von Luxburg , Debarghya Ghoshdastidar