The Gibbs Centroid Sampler is a software package designed for locating conserved elements in biopolymer sequences. The Gibbs Centroid Sampler reports a centroid alignment, i.e. an alignment that has the minimum total distance to the set of samples chosen from the a posteriori probability distribution of transcription factor binding-site alignments. In so doing, it garners information from the f...

A method for improving centroid-based clustering is suggested. The improvement built on diversification of the k-means++ initialization. algorithm claimed to be a better version k-means tested by computational set-up, where dataset size, number features, and clusters are varied. statistics obtained testing have shown that, in roughly 50 % instances cluster, outputs worse results than with rando...

Given a finite configuration of points in a metric space, a Steiner center (respectively, a centroid) is the point of the space (respectively, of the configuration) that minimizes the sum of the distances from all its elements. Working on the k-dimensional real space endowed with the Manhattan distance, we study the approximate algorithm that takes a point of minimum distance from the Steiner c...

In this paper, we introduce new algorithms that perform clustering and feature weighting simultaneously and in an unsupervised manner. The proposed algorithms are computationally and implementation ally simple, and learn a different set of feature weights for each identified cluster. The cluster dependent feature weights offer two advantages. First, they guide the clustering process to partitio...

A novel approach for human silhouette recognition is presented. The method is based on Fourier descriptors. We made an analysis of which and how many descriptors are enough to have a general human silhouette representation, and concluded that a reduced number of components, low and high frecuency, is sufficient for representing a human silhouette and for its recognition in different posses. Bas...

Let P be an H-polytope in R with vertex set V . The vertex centroid is defined as the average of the vertices in V . We prove that computing the vertex centroid of an H-polytope is #P-hard. Moreover, we show that even just checking whether the vertex centroid lies in a given halfspace is already #P-hard for H-polytopes. We also consider the problem of approximating the vertex centroid by findin...

The orthocentroidal circle of a non-equilateral triangle has diameter GH where G is the centroid and H is the orthocenter. We show that the Fermat, Gergonne and symmedian points are confined to, and range freely over the interior disk punctured at its center. The Mittenpunkt is also confined to and ranges freely over another punctured disk, and the second Fermat point is confined to and ranges ...

In the title molecule, C(6)H(6)N(4)S(2), a twofold rotation axis passes through the mid-point of the S-S bond. The C-S-S-C torsion angle is 83.62 (17)°. π-π stacking between imidazole rings of adjacent mol-ecules is observed in the crystal structure, the centroid-centroid distance being 3.447 (2) Å. Inter-molecular N-H⋯S hydrogen bonding results in the formation of a linear chain in the c-axis ...

The asymmetric unit of the title compound, C(16)H(12)F(4)N(2), comprises half of the potentially bidentate Schiff base ligand, with an inversion centre located at the mid-point of the central C-C bond. The crystal packing is stabilized by inter-molecular C-H⋯N and π-π inter-actions [centroid-centroid distance = 3.6793 (12) Å and inter-planar spacing = 3.4999 (7) Å].