17,284 research outputs found
Anisotropy and percolation threshold in a multifractal support
Recently a multifractal object, , was proposed to study percolation
properties in a multifractal support. The area and the number of neighbors of
the blocks of show a non-trivial behavior. The value of the
probability of occupation at the percolation threshold, , is a function
of , a parameter of which is related to its anisotropy. We
investigate the relation between and the average number of neighbors of
the blocks as well as the anisotropy of
Using choreographies to support the gamification process on the development of an application to reduce electricity costs
Building automation systems contribute to reduce electricity costs by managing distributed energy resources in an efficient way. However, a large share of consumption cannot be optimized through automation alone, since it mainly depends on human interactions. Gamification can be used as one form of changing users’ behaviours [1], but its implementation does require assumptions on the behaviour patterns that need to
be identified, encouraged, or discouraged. To tackle this problem, we propose a framework that joins building automation solutions with gamification techniques to enable behavioural demand response.info:eu-repo/semantics/publishedVersio
Strong evidences for a nonextensive behavior of the rotation period in Open Clusters
Time-dependent nonextensivity in a stellar astrophysical scenario combines
nonextensive entropic indices derived from the modified Kawaler's
parametrization, and , obtained from rotational velocity distribution. These
's are related through a heuristic single relation given by , where is the cluster age. In a nonextensive
scenario, these indices are quantities that measure the degree of
nonextensivity present in the system. Recent studies reveal that the index
is correlated to the formation rate of high-energy tails present in the
distribution of rotation velocity. On the other hand, the index is
determined by the stellar rotation-age relationship. This depends on the
magnetic field configuration through the expression , where
and denote the saturation level of the star magnetic field and its
topology, respectively. In the present study, we show that the connection
is also consistent with 548 rotation period data for single
main-sequence stars in 11 Open Clusters aged less than 1 Gyr. The value of
2.5 from our unsaturated model shows that the mean magnetic field
topology of these stars is slightly more complex than a purely radial field.
Our results also suggest that stellar rotational braking behavior affects the
degree of anti-correlation between and cluster age . Finally, we suggest
that stellar magnetic braking can be scaled by the entropic index .Comment: 6 pages and 2 figures, accepted to EPL on October 17, 201
Float-polishing process and analysis of float-polished quartz
A fluid-mechanical model is developed for the float-polishing process. In this model laminar flow between the sample and the lap results in pressure gradients at the grooves that support the sample on a fluid layer. The laminar fluid motion also produces supersmooth, damage-free surfaces. Quartz substrates for applications in high-stress environments were float polished, and their surfaces were analyzed by optical scatterometry, photoacoustic spectroscopy, and atomic force microscopy. The removal of 100 µm of material by a lapping-polishing process, with final float polishing, left low levels of subsurface damage, with a surface roughness of approximately 0.2-nm rms
Nonclassical correlation in NMR quadrupolar systems
The existence of quantum correlation (as revealed by quantum discord), other
than entanglement and its role in quantum-information processing (QIP), is a
current subject for discussion. In particular, it has been suggested that this
nonclassical correlation may provide computational speedup for some quantum
algorithms. In this regard, bulk nuclear magnetic resonance (NMR) has been
successfully used as a test bench for many QIP implementations, although it has
also been continuously criticized for not presenting entanglement in most of
the systems used so far. In this paper, we report a theoretical and
experimental study on the dynamics of quantum and classical correlations in an
NMR quadrupolar system. We present a method for computing the correlations from
experimental NMR deviation-density matrices and show that, given the action of
the nuclear-spin environment, the relaxation produces a monotonic time decay in
the correlations. Although the experimental realizations were performed in a
specific quadrupolar system, the main results presented here can be applied to
whichever system uses a deviation-density matrix formalism.Comment: Published versio
Retinal Vessel Segmentation Using the 2-D Morlet Wavelet and Supervised Classification
We present a method for automated segmentation of the vasculature in retinal
images. The method produces segmentations by classifying each image pixel as
vessel or non-vessel, based on the pixel's feature vector. Feature vectors are
composed of the pixel's intensity and continuous two-dimensional Morlet wavelet
transform responses taken at multiple scales. The Morlet wavelet is capable of
tuning to specific frequencies, thus allowing noise filtering and vessel
enhancement in a single step. We use a Bayesian classifier with
class-conditional probability density functions (likelihoods) described as
Gaussian mixtures, yielding a fast classification, while being able to model
complex decision surfaces and compare its performance with the linear minimum
squared error classifier. The probability distributions are estimated based on
a training set of labeled pixels obtained from manual segmentations. The
method's performance is evaluated on publicly available DRIVE and STARE
databases of manually labeled non-mydriatic images. On the DRIVE database, it
achieves an area under the receiver operating characteristic (ROC) curve of
0.9598, being slightly superior than that presented by the method of Staal et
al.Comment: 9 pages, 7 figures and 1 table. Accepted for publication in IEEE
Trans Med Imag; added copyright notic
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