English
Related papers

Related papers: Parametrization of sunspot groups based on machine…

200 papers

Mapper algorithm can be used to build graph-based representations of high-dimensional data capturing structurally interesting features such as loops, flares or clusters. The graph can be further annotated with additional colouring of…

Numerical Analysis · Mathematics 2020-12-04 Ciara Frances Loughrey , Nick Orr , Anna Jurek-Loughrey , Paweł Dłotko

The long term study of the Sun is necessary if we are to determine the evolution of sunspot properties and thereby inform modeling of the solar dynamo, particularly on scales of a solar cycle. We aim to determine a number of sunspot…

Solar and Stellar Astrophysics · Physics 2011-08-23 Fraser T. Watson , Lyndsay Fletcher , Stephen Marshall

The sunspots and other solar activity indicators tend to cluster on the surface of the Sun.These clusters very often occur at certain longitudes that persist in time.It is of general interest to find new and simple ways to characterize the…

Solar and Stellar Astrophysics · Physics 2015-05-14 J. Pelt , M. J. Korpi , I. Tuominen

We present an approach to learning features that represent the local geometry around a point in an unstructured point cloud. Such features play a central role in geometric registration, which supports diverse applications in robotics and 3D…

Computer Vision and Pattern Recognition · Computer Science 2017-09-18 Marc Khoury , Qian-Yi Zhou , Vladlen Koltun

We describe a revised collection of the number of sunspot groups from 1610 to the present. This new collection is based on the work of Hoyt and Schatten (Solar Phys. 179, 189, 1998). The main changes are the elimination of a considerable…

Solar and Stellar Astrophysics · Physics 2023-01-06 J. M. Vaquero , L. Svalgaard , V. M. S. Carrasco , F. Clette , L. Lefèvre , M. C. Gallego , R. Arlt , A. J. P. Aparicio , J. -G. Richard , R. Howe

Revealing latent structure in data is an active field of research, having introduced exciting technologies such as variational autoencoders and adversarial networks, and is essential to push machine learning towards unsupervised knowledge…

Machine Learning · Computer Science 2019-10-25 Daniel C. Castro , Jeremy Tan , Bernhard Kainz , Ender Konukoglu , Ben Glocker

Many modern wireless devices with accurate positioning needs also have access to vision sensors, such as a camera, radar, and Light Detection and Ranging (LiDAR). In scenarios where wireless-based positioning is either inaccurate or…

Computer Vision and Pattern Recognition · Computer Science 2025-02-03 Haozhou Hu , Harpreet S. Dhillon , R. Michael Buehrer

Early telescopic observations of sunspots were conducted with instruments of relatively small aperture. These instruments also suffered from a higher level of scattered light, and the human eye served as a "detector". The eye's ability to…

Solar and Stellar Astrophysics · Physics 2019-07-12 Nina V. Karachik , Alexei A. Pevtsov , Yury A. Nagovitsyn

Sunspot numbers provide the longest continuous record of solar activity and remain a key index for heliophysical research and space-weather applications. Standard sunspot determination relies on visual inspection and algorithmic…

Solar and Stellar Astrophysics · Physics 2026-03-25 Fabian C. Quintero-Pareja , Diederik A. Montano-Burbano , Santiago Quintero-Pareja , D. Sierra-Porta

The morphology of circular polarisation profiles from solar spectropolarimetric observations encode information about the magnetic field strength, inclination, and line-of-sight velocity gradients. Previous studies used manual methods or…

Solar and Stellar Astrophysics · Physics 2025-05-21 Ryan James Campbell , Mihalis Mathioudakis , Carlos Quintero Noda , Peter Keys , David Orozco Suárez

Aims. In this paper, we aim to study the time dependence of sunspot group areas in a large sample composed of various databases spanning over 130 years, used state-of-the-art statistical methods. Methods. For a carefully selected but…

Solar and Stellar Astrophysics · Physics 2021-09-08 Emese Forgács-Dajka , László Dobos , István Ballai

Heliographic coordinates are used to identify the positions of solar features, especially the sunspot groups on the Sun's surface. Tracking the positions of sunspot groups provides information about solar rotation and the movement behavior…

Solar and Stellar Astrophysics · Physics 2015-06-22 H. Cakmak

Latent factor models are the canonical statistical tool for exploratory analyses of low-dimensional linear structure for an observation matrix with p features across n samples. We develop a structured Bayesian group factor analysis model…

Methodology · Statistics 2015-11-12 Shiwen Zhao , Chuan Gao , Sayan Mukherjee , Barbara E Engelhardt

Latent variable models for network data extract a summary of the relational structure underlying an observed network. The simplest possible models subdivide nodes of the network into clusters; the probability of a link between any two nodes…

Machine Learning · Computer Science 2012-07-03 Konstantina Palla , David Knowles , Zoubin Ghahramani

Disentangled representations seek to recover latent factors of variation underlying observed data, yet their identifiability is still not fully understood. We introduce a unified framework in which disentanglement is achieved through…

Machine Learning · Computer Science 2026-05-12 Stefan Matthes , Zhiwei Han , Hao Shen

Feature related particle data analysis plays an important role in many scientific applications such as fluid simulations, cosmology simulations and molecular dynamics. Compared to conventional methods that use hand-crafted feature…

Graphics · Computer Science 2022-03-23 Haoyu Li , Han-Wei Shen

Motivated by the computational and storage challenges that dense embeddings pose, we introduce the problem of latent network summarization that aims to learn a compact, latent representation of the graph structure with dimensionality that…

Social and Information Networks · Computer Science 2019-06-24 Di Jin , Ryan Rossi , Danai Koutra , Eunyee Koh , Sungchul Kim , Anup Rao

Few-shot learning (FSL) aims to learn novel visual categories from very few samples, which is a challenging problem in real-world applications. Many methods of few-shot classification work well on general images to learn global…

Computer Vision and Pattern Recognition · Computer Science 2020-12-15 Xiaojian He , Jinfu Lin , Junming Shen

In this study, we evaluate several classifiers and focus on selecting a minimal set of appropriate material features. Our objective is to propose and discuss general strategies for reducing the number of descriptors required for material…

Other Condensed Matter · Physics 2025-10-01 Giovanni Trezza , Eliodoro Chiavazzo

Solar activity is an important driver of long-term climate trends and must be accounted for in climate models. Unfortunately, direct measurements of this quantity over long periods do not exist. The only observation related to solar…

Solar and Stellar Astrophysics · Physics 2023-01-12 Sophie Mathieu , Laure Lefèvre , Rainer von Sachs , Véronique Delouille , Christian Ritter , Frédéric Clette