7,205 research outputs found
First Law, Counterterms and Kerr-AdS_5 Black Holes
We apply the counterterm subtraction technique to calculate the action and
other quantities for the Kerr--AdS black hole in five dimensions using two
boundary metrics; the Einstein universe and rotating Einstein universe with
arbitrary angular velocity. In both cases, the resulting thermodynamic
quantities satisfy the first law of thermodynamics. We point out that the
reason for the violation of the first law in previous calculations is that the
rotating Einstein universe, used as a boundary metric, was rotating with an
angular velocity that depends on the black hole rotation parameter. Using a new
coordinate system with a boundary metric that has an arbitrary angular
velocity, one can show that the resulting physical quantities satisfy the first
law.Comment: 19 pages, 1 figur
Automatic skin segmentation for gesture recognition combining region and support vector machine active learning
Skin segmentation is the cornerstone of many applications such as gesture recognition, face detection, and objectionable image filtering. In this paper, we attempt to address the skin segmentation problem for gesture recognition. Initially, given a gesture video sequence, a generic skin model is applied to the first couple of frames to automatically collect the training data. Then, an SVM classifier based on active learning is used to identify the skin pixels. Finally, the results are improved by incorporating region segmentation. The proposed algorithm is fully automatic and adaptive to different signers. We have tested our approach on the ECHO database. Comparing with other existing algorithms, our method could achieve better performance
-dimensional charged Anti-de-Sitter black holes in gravity
We present a -dimensional charged Anti-de-Sitter black hole solutions in
gravity, where and . These solutions are
characterized by flat or cylindrical horizons. The interesting feature of these
solutions is the existence of inseparable electric monopole and quadrupole
terms in the potential which share related momenta, in contrast with most of
the known charged black hole solutions in General Relativity and its
extensions. Furthermore, these solutions have curvature singularities which are
milder than those of the known charged black hole solutions in General
Relativity and Teleparallel Gravity. This feature can be shown by calculating
some invariants of curvature and torsion tensors. Furthermore, we calculate the
total energy of these black holes using the energy-momentum tensor. Finally, we
show that these charged black hole solutions violate the first law of
thermodynamics in agreement with previous results.Comment: 11 Pages, will appear in JHE
Rotating charged AdS solutions in quadratic gravity
We present a class of asymptotically anti-de Sitter charged rotating black
hole solutions in gravity in -dimensions, where . These solutions are nontrivial extensions of the solutions presented in
\cite{Lemos:1994xp} and \cite{Awad:2002cz} in the context of general
relativity. They are characterized by cylindrical, toroidal or flat horizons,
depending on global identifications. The static charged black hole
configurations obtained in \cite{Awad:2017tyz} are recovered as special cases
when the rotation parameters vanish. Similar to \cite{Awad:2017tyz} the static
black holes solutions have two different electric multipole terms in the
potential with related moments. Furthermore, these solutions have milder
singularities compared to their general relativity counterparts. Using the
conserved charges expressions obtained in \cite{Ulhoa:2013gca} and
\cite{Maluf:2008ug} we calculate the total mass/energy and the angular momentum
of these solutions.Comment: 11 pages, Version accepted in EPJ
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