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Archetypal analysis: an alternative to clustering for unsupervised texture segmentation
(International Society for Stereology & Image Analysis, 2019-04)
Texture segmentation is one of the main tasks in image applications, specifically in remote sensing, where the objective is to segment high-resolution images of natural landscapes into different cover types. Often the focus ...
Symmetrically processed splitting integrators for enhanced hamiltonian monte carlo sampling
(Society for Industrial and Applied Mathematics, 2021-09-23)
We construct integrators to be used in Hamiltonian (or Hybrid) Monte Carlo sampling. The new integrators are easily implementable and, for a given computational budget, may deliver five times as many accepted proposals as ...
Spatio-temporal hierarchical Bayesian analysis of wildfires with Stochastic Partial Differential Equations. A case study from Valencian Community (Spain)
(Taylor & Francis, 2019-09-04)
The spatio-temporal study of wildfires has two complex elements that are the computational efficiency and longtime processing. Modelling the spatial variability of a wildfire could be performed in different ways, and an ...
Conditions for Sylow 2-subgroups of the Fixed Point Subgroup Implying Solubility
(Cambridge University Press, 2018)
Let A and G be finite groups and suppose that A acts via automorphisms
on G with (|A|, |G|) = 1. We study how certain conditions on the
Sylow 2-subgroups of the fixed point subgroup of the action, CG(A), may
imply the ...
An Arad and Fisman’s Theorem on Products of Conjugacy Classes Revisited
(Springer, 2022)
A theorem of Z. Arad and E. Fisman establishes that if A and
B are two non-trivial conjugacy classes of a finite group G such that
either AB = A ∪ B or AB = A−1 ∪ B, then G cannot be a non-abelian
simple group. We ...
Archetypal analysis with missing data: see all samples by looking at a few based on extreme profiles
(American Statistical AssociationTaylor & Francis, 2019-05-13)
In this paper we propose several methodologies for handling missing or incomplete data in Archetype analysis (AA) and Archetypoid analysis (ADA). AA seeks to find archetypes, which are convex combinations of data points, ...
Detecting and visualizing differences in brain structures with SPHARM and functional data analysis
(Elsevier, 2020-08-07)
A new procedure for classifying brain structures described by SPHARM is presented. We combine a dimension reduction technique (functional principal component analysis or functional independent component analysis) with ...
Robust archetypoids for anomaly detection in big functional data
(Springer, 2020-08-03)
Archetypoid analysis (ADA) has proven to be a successful unsupervised statistical technique to identify extreme observations in the periphery of the data cloud, both in classical multivariate data and functional data. ...
When a totally bounded group topology is the Bohr topology of a LCA group
(Elsevier, 2019-06-01)
We look at the Bohr topology of maximally almost periodic groups (MAP, for short). Among
other results, we investigate when a Hausdorff precompact abelian group (G; w) is the Bohr re
ection of
a locally compact abelian ...
Archetypal shapes based on landmarks and extension to handle missing data
(Springer Verlag, 2017-10)
Archetype and archetypoid analysis are extended to shapes. The objective is to find representative shapes. Archetypal shapes are pure (extreme) shapes. We focus on the case where the shape of an object is represented by a ...