UPGMA (Unweighted Pair Group Method with Arithmetic Mean) is a widely used clustering method. Here we show that UPGMA is a greedy heuristic for the normalized equidistant minimum evolution (NEME) problem, that is, finding a rooted tree that minimizes the minimum evolution score relative to the dissimilarity matrix among all rooted trees with the same leaf-set in which all leaves have the same d...

Synchronous electrical activity in di erent brain regions is generally assumed to imply functional relationships between these regions. A measure for this synchrony is electroencephalography (EEG) coherence. Recently, we developed a new method for data-driven visualization of high-density EEG coherence, avoiding the visual clutter of conventional data-driven methods. It uses the concept of maxi...

In this paper, we consider two important problems defined on finite metric spaces, and provide efficient new algorithms and approximation schemes for these problems on inputs given as graph shortest path metrics or high-dimensional Euclidean metrics. The first of these problems is the greedy permutation (or farthest-first traversal) of a finite metric space: a permutation of the points of the s...

The randomized group-greedy (RGG) method and its customized for large-scale sensor selection problems are proposed. greedy algorithm is applied straightforwardly to the (GG) method, a also considered. In part of compressed candidates selected using common or other low-cost methods. This strategy compensates deterioration solution due candidates. proposed methods implemented based on D- E-optima...

image segmentation is an essential issue in image description and classification. currently, in many real applications, segmentation is still mainly manual or strongly supervised by a human expert, which makes it irreproducible and deteriorating. moreover, there are many uncertainties and vagueness in images, which crisp clustering and even type-1 fuzzy clustering could not handle. hence, type-...

Clustering has an extensive and long history in a variety of scientific fields. Several recent studies of complex networks have suggested that the clustering analysis on networks has been an emerging research issue in data mining due to its variety of applications. Many graph clustering algorithms have been proposed in recent past, however, this clustering approach remains a challenging problem...

Abstract R -process enhanced stars with [Eu/Fe] ≥ +0.7 (so-called r -II stars) are believed to have formed in an extremely neutron-rich environment which a rare astrophysical event (e.g., neutron-star merger) occurred. This scenario is supported by the existence of ultra-faint dwarf galaxy, Reticulum II, where most highly elements. In this scenario, some small fraction galaxies around Milky Way...