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The spatial interaction between two or more classes of points may cause spatial clustering patterns such as segregation or association, which can be tested using a nearest neighbor contingency table (NNCT). A NNCT is constructed using the…

统计方法学 · 统计学 2008-07-29 Elvan Ceyhan

Normalizing flows model a complex target distribution in terms of a bijective transform operating on a simple base distribution. As such, they enable tractable computation of a number of important statistical quantities, particularly…

机器学习 · 计算机科学 2022-09-01 Chandramouli Shama Sastry , Andreas Lehrmann , Marcus Brubaker , Alexander Radovic

In this study, we investigate the potential of mark-weighted angular correlation functions (MACFs), which integrate $\beta$-cosmic-web classification with angular correlation function analysis to improve cosmological constraints. Using SDSS…

宇宙学与河外天体物理 · 物理学 2025-06-03 Fenfen Yin , Liang Xiao , Wenying Du , Zhujun Jiang , Zhiwei Min , Jaime Forero-Romero , Jiacheng Ding , Le Zhang , Xiao-Dong Li

Data-driven neighborhood definitions and graph constructions are often used in machine learning and signal processing applications. k-nearest neighbor~(kNN) and $\epsilon$-neighborhood methods are among the most common methods used for…

机器学习 · 计算机科学 2023-04-18 Sarath Shekkizhar , Antonio Ortega

Nearest neighbor (NN) graph based visual re-ranking has emerged as a powerful approach for improving retrieval accuracy, offering the advantages of effectively exploring high-dimensional manifolds without requiring additional fine-tuning.…

计算机视觉与模式识别 · 计算机科学 2025-07-09 Jaeyoon Kim , Yoonki Cho , Taeyoung Kim , Sung-Eui Yoon

We present the Mock Map Facility, a powerful tool to generate mock catalogues or images from semi-analytically post-processed snapshots of cosmological N-body simulations. The paper describes in detail an efficient technique to create such…

天体物理学 · 物理学 2009-11-10 J. Blaizot , Y. Wadadekar , B. Guiderdoni , S. Colombi , E. Bertin , F. R. Bouchet , J. E. G. Devriendt , S. Hatton

In order to quantify the error budget in the measured probability distribution functions of cell densities, the two-point statistics of cosmic densities in concentric spheres is investigated. Bias functions are introduced as the ratio of…

宇宙学与河外天体物理 · 物理学 2016-06-08 Sandrine Codis , Francis Bernardeau , Christophe Pichon

$K$-NN classifier is one of the most famous classification algorithms, whose performance is crucially dependent on the distance metric. When we consider the distance metric as a parameter of $K$-NN, learning an appropriate distance metric…

机器学习 · 计算机科学 2019-11-26 Kun Song

We investigate the large-scale distribution of galaxy clusters taken from several X-ray catalogs. Different statistics of clustering like the conditional correlation function (CCF) and the minimal spanning tree (MST) as well as void…

天体物理学 · 物理学 2008-05-16 A. V. Tikhonov , A. I. Kopylov , S. Gottlober , G. Yepes

We consider two parametrized random digraph families, namely, proportional-edge and central similarity proximity catch digraphs (PCDs) and compare the performance of these two PCD families in testing spatial point patterns. These PCD…

组合数学 · 数学 2010-10-22 Elvan Ceyhan

In recent years, deep learning approaches have achieved state-of-the-art results in the analysis of point cloud data. In cosmology, galaxy redshift surveys resemble such a permutation invariant collection of positions in space. These…

宇宙学与河外天体物理 · 物理学 2022-11-23 Sotiris Anagnostidis , Arne Thomsen , Tomasz Kacprzak , Tilman Tröster , Luca Biggio , Alexandre Refregier , Thomas Hofmann

We introduce a new technique for following the formation and evolution of galaxies in cosmological N-body simulations. Dissipationless simulations are used to track the formation and merging of dark matter halos as a function of redshift.…

天体物理学 · 物理学 2009-10-30 Guinevere Kauffmann , Joerg M. Colberg , Antonaldo Diaferio , Simon D. M. White

The problem of supervised classification (or discrimination) with functional data is considered, with a special interest on the popular k-nearest neighbors (k-NN) classifier. First, relying on a recent result by Cerou and Guyader (2006), we…

机器学习 · 统计学 2008-06-18 Amparo Baillo , Antonio Cuevas

Continuous glucose monitoring (CGM) is a minimally invasive technology that measures blood glucose every few minutes for weeks or months at a time. CGM data are often collected in the free-living environment and is strongly related to…

统计方法学 · 统计学 2025-09-04 Marcos Matabuena , Ciprian M. Crainiceanu

The non-Euclidean geometry of spacetime induces an anisotropy in the apparent correlation function of high-redshift quasars. This effect can constrain the cosmological constant \Lambda independent of any assumptions about evolution of…

天体物理学 · 物理学 2009-10-30 Piotr A. Popowski , David H. Weinberg , Barbara S. Ryden , Patrick S. Osmer

As one type of efficient unsupervised learning methods, clustering algorithms have been widely used in data mining and knowledge discovery with noticeable advantages. However, clustering algorithms based on density peak have limited…

机器学习 · 计算机科学 2019-11-26 Jianguo Chen , Philip S. Yu

We consider conditional tests for non-negative discrete exponential families. We develop two Markov Chain Monte Carlo (MCMC) algorithms which allow us to sample from the conditional space and to perform approximated tests. The first…

统计计算 · 统计学 2017-07-27 Roberto Fontana , Francesca Romana Crucinio

A new clustering accuracy measure is proposed to determine the unknown number of clusters and to assess the quality of clustering of a data set given in any dimensional space. Our validity index applies the classical nonparametric…

统计方法学 · 统计学 2022-02-15 Soumita Modak

Maximising the information that can be extracted from weak lensing measurements is a key goal for upcoming surveys such as LSST and Euclid. This is typically achieved through statistics that are complementary to the cosmic shear two-point…

宇宙学与河外天体物理 · 物理学 2022-05-11 Christopher T. Davies , Marius Cautun , Benjamin Giblin , Baojiu Li , Joachim Harnois-Déraps , Yan-Chuan Cai

Lightcone observations are the natural data format of galaxy surveys, but their evolving geometry breaks the translational symmetry assumed by standard convolutional neural networks (CNNs). In particular, applying CNNs to 3D gridded…

宇宙学与河外天体物理 · 物理学 2026-03-30 Min Zhiwei , Xiao Xu , Jiang Zhujun , Xiao Liang , Yin Fenfen , Ding Jiacheng , Miao Haitao , Chen Shupei , Lin Qiufan , Wang yang , Zhang Le , Li XiaoDong