1,265 research outputs found
Optimal Capacity of the Blume-Emery-Griffiths perceptron
A Blume-Emery-Griffiths perceptron model is introduced and its optimal
capacity is calculated within the replica-symmetric Gardner approach, as a
function of the pattern activity and the imbedding stability parameter. The
stability of the replica-symmetric approximation is studied via the analogue of
the Almeida-Thouless line. A comparison is made with other three-state
perceptrons.Comment: 10 pages, 8 figure
A spherical Hopfield model
We introduce a spherical Hopfield-type neural network involving neurons and
patterns that are continuous variables. We study both the thermodynamics and
dynamics of this model. In order to have a retrieval phase a quartic term is
added to the Hamiltonian. The thermodynamics of the model is exactly solvable
and the results are replica symmetric. A Langevin dynamics leads to a closed
set of equations for the order parameters and effective correlation and
response function typical for neural networks. The stationary limit corresponds
to the thermodynamic results. Numerical calculations illustrate our findings.Comment: 9 pages Latex including 3 eps figures, Addition of an author in the
HTML-abstract unintentionally forgotten, no changes to the manuscrip
Measurement of mesoscopic High- superconductors using Si mechanical micro-oscillators
In a superconducting mesoscopic sample, with dimensions comparable to the
London penetration depth, some properties are qualitatively different to those
found in the bulk material. These properties include magnetization, vortex
dynamics and ordering of the vortex lattice. In order to detect the small
signals produced by this kind of samples, new instruments designed for the
microscale are needed. In this work we use micromechanical oscillators to study
the magnetic properties of a BiSrCaCuO disk with a
diameter of 13.5 microns and a thickness of 2.5 microns. The discussion of our
results is based on the existence and contribution of inter and intra layer
currents.Comment: 4 pages, 6 figure
How the Belgian wind farm business made us discover the challenging environment of marine sand dunes
During the last decade, it has become clear that sand dunes are important features in the Belgian wind farm concession area. Because they influence not only the design seabed levels, but also the hydrodynamic forcings and installation methods for both cable and foundations, the study of the seabed morphodynamics is essential for all wind farm projects. This paper starts with an overview of the geographic and morphological setting of the Belgian wind farm concession areas and presents an overview of the key features of the bedforms in the different concessions. Next the importance and impact of the sand dunes during the design and development of these wind farms is illustrated by exploring the different types of studies and investigations which have been performed in relation to seabed & morphology, the hydrodynamic loadings, the installation methods and the environmental impact assessments
Vortex liquid correlations induced by in-plane field in underdoped Bi2Sr2CaCu2O8+d
By measuring the Josephson Plasma Resonance, we have probed the influence of
an in-plane magnetic field on the pancake vortex correlations along the c-axis
in heavily underdoped Bi2Sr2CaCu2O8+d (Tc = 72.4 +/- 0.6 K) single crystals
both in the vortex liquid and in the vortex solid phase. Whereas the in-plane
field enhances the interlayer phase coherence in the liquid state close to the
melting line, it slightly depresses it in the solid state. This is interpreted
as the result of an attractive force between pancake vortices and Josephson
vortices, apparently also present in the vortex liquid state. The results
unveil a boundary between a correlated vortex liquid in which pancakes adapt to
Josephson vortices, and the usual homogeneous liquid.Comment: 2 pages, submitted to the Proceedings of M2S HTSC VIII Dresde
Minimalist AdaBoost for blemish identification in potatoes
We present a multi-class solution based on minimalist Ad-
aBoost for identifying blemishes present in visual images of potatoes.
Using training examples we use Real AdaBoost to rst reduce the fea-
ture set by selecting ve features for each class, then train binary clas-
siers for each class, classifying each testing example according to the
binary classier with the highest certainty. Against hand-drawn ground
truth data we achieve a pixel match of 83% accuracy in white potatoes
and 82% in red potatoes. For the task of identifying which blemishes
are present in each potato within typical industry dened criteria (10%
coverage) we achieve accuracy rates of 93% and 94%, respectively
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