1,924 research outputs found

    A Dynamical Cosmological Term from the Verlinde's Maps

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    In this letter it is proposed another generalization of the Verlinde's maps for the case Λ≠0\Lambda \neq 0. Thermodynamical arguments combined with this proposal conduce to a inverse square-law cosmological term behavior.Comment: 7 pages, minor changes added. v3: Minor changes in title, content and style; acknowledgments and references added; v4 Minor changes and references adde

    Corrections to the Entropy in Higher Order Gravity

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    Thermal corrections to the entropy of black holes in the Lovelock gravity are calculated. As the thermodynamic behavior of the black holes of this theory falls into two classes, the thermodynamic quantities are computed in each case. Finally, the logarithmic prefactors are obtained in two different limits.Comment: 11 pages. Comments and references added.v3.Minor changes in content and style, Proceedings of the Conference 100 Years of Relativity, Sao Paulo, Brazil, August 200

    Speciation of chilean Rhinocryptidae (Avian) based on their behaviour

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    The current classification of the chilean representatives of the passerine family Rhinocryptidae includes eight species. Three of them contain subspecies that don't exhibit clear differences. Moreover, differences among two lineages of _Scytalopus_ genera and two species of _Pteroptochos_ are cryptic. We propose a new methodology based on ecological and behavioural patterns in order to understand the concept of speciation in this group of birds. According to our results, we postulate that there is not a cut criteria to establish differences among three sister lineages of current classification. This way the methodology developed by us does not allow to establish divergence for a given common ancestor. Our methodology allows to establish comparison among previously determined phylogenetic lineages. Our results show how when integrating behaviour and ecological terms as biological traits next to morphological characters of the plumage, it allows us to conclude that there is decrease of the distances among sister lineages in the cluster tree

    Ensemble of Example-Dependent Cost-Sensitive Decision Trees

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    Several real-world classification problems are example-dependent cost-sensitive in nature, where the costs due to misclassification vary between examples and not only within classes. However, standard classification methods do not take these costs into account, and assume a constant cost of misclassification errors. In previous works, some methods that take into account the financial costs into the training of different algorithms have been proposed, with the example-dependent cost-sensitive decision tree algorithm being the one that gives the highest savings. In this paper we propose a new framework of ensembles of example-dependent cost-sensitive decision-trees. The framework consists in creating different example-dependent cost-sensitive decision trees on random subsamples of the training set, and then combining them using three different combination approaches. Moreover, we propose two new cost-sensitive combination approaches; cost-sensitive weighted voting and cost-sensitive stacking, the latter being based on the cost-sensitive logistic regression method. Finally, using five different databases, from four real-world applications: credit card fraud detection, churn modeling, credit scoring and direct marketing, we evaluate the proposed method against state-of-the-art example-dependent cost-sensitive techniques, namely, cost-proportionate sampling, Bayes minimum risk and cost-sensitive decision trees. The results show that the proposed algorithms have better results for all databases, in the sense of higher savings.Comment: 13 pages, 6 figures, Submitted for possible publicatio
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