1,653 research outputs found
A non-conformal multi-resolution preconditioner in the MoM solution of large multi-scale structures
The extension of the surface integral equations (SIEs) [1] to non-conforming meshes has ignited intense research in the last years with the goal of finding a versatile and accurate method to address large and multi-scale complex problems, greatly simplifying computer-aided-design (CAD) generation and meshing processes
A non-conformal multi-resolution preconditioner in the MoM solution of large multi-scale structures
An efficient method to improve the convergence in non-conformal meshes including an automatic quasi-Helmholtz decomposition has been developed for the simulation of nonconforming meshes using the novel Multibranch Rao-Wilton-Glisson (MB-RWG) basis functions. Numerical experiments will be shown to illustrate the great flexibility of this approach for the solution of small-frequency and large multi-scale objects
Iris recognition using the JAVAVis Library
This project has been created to develop a
biometric identification system through a man’s iris using a
computer to perform the processing of the pictures. To develop
this application, and to differentiate the project from others
who have already implemented, we have used the image
processing library JAVAVis and JAVA as a programming
language
FooPar: A Functional Object Oriented Parallel Framework in Scala
We present FooPar, an extension for highly efficient Parallel Computing in
the multi-paradigm programming language Scala. Scala offers concise and clean
syntax and integrates functional programming features. Our framework FooPar
combines these features with parallel computing techniques. FooPar is designed
modular and supports easy access to different communication backends for
distributed memory architectures as well as high performance math libraries. In
this article we use it to parallelize matrix matrix multiplication and show its
scalability by a isoefficiency analysis. In addition, results based on a
empirical analysis on two supercomputers are given. We achieve close-to-optimal
performance wrt. theoretical peak performance. Based on this result we conclude
that FooPar allows to fully access Scala's design features without suffering
from performance drops when compared to implementations purely based on C and
MPI
Rational exploitation of a granite outcrop
[Abstract] This piece analizes the possibilities of mining exploitation in a little outcrop of rOSfl granite. The zone has been researched, recognizing the main structural discontinuities, and characterizing the rock mass by the geomechanic classificationofBARTON. Two core drilling have been made to study the evolution ofthe deeper bed. The volume ofthe bed has been calculated by geometric calculation in the researched area. The theories ofCASTAING and RABU have been developed to estimate the useful volume of the bed for a minimum block size of 1 m3. We have implerrĂented a computer program in base ofEXCEL 4.0. The result is a useful volume of 51.67 %. By the application of the reduction coefficients ofsterility and irregularity, the maximum estimated efficiency of the exploitation is 33 %
Emissões de N2o de um chernossolo cultivado : o tempo ideal do dia para amostragem e papel da temperatura do solo
1814-1819The correct use of closed field chambers to determine N2O emissions requires defining the time of day that best represents the daily mean N2O flux. A short-term field experiment was carried out on a Mollisol soil, on which annual crops were grown under no-till management in the Pampa Ondulada of Argentina. The N2O emission rates were measured every 3 h for three consecutive days. Fluxes ranged from 62.58 to 145.99 ug N-N2O m-2 h-1 (average of five field chambers) and were negatively related (R2 equal 0.34, p less than 0.01) to topsoil temperature (14 - 20 oC). N2O emission rates measured between 9:00 and 12:00 am presented a high relationship to daily mean N2O flux (R2 equal 0.87, p less than 0.01), showing that, in the study region, sampling in the mornings is preferable for GHG
On residual circulation of the Ria of Vigo, using a 3-D baroclinic model
The present paper studies circulation in the Ria of Vigo (northwest Spain) by means of a 3-D baroclinic model coupled with a Lagrangian model of dispersion. The model is examined to obtain the residual currents' underlying periodic tidal movements. These currents are related to the quality of water because they determine the residence time. The model is forced at the mouth of the estuary with the most important tidal harmonics, and at the innermost zone with the freshwater discharge due to the presence of the Oitaven River. Results show that the area under study has a two-layered circulation, where most of water enters the estuary through the southern mouth and leaves it through the northern one.Se estudia la circulaciĂłn de la rĂa de Vigo (noroeste de España) por medio de un modelo tridimensional baroclĂnico acoplado a un modelo lagrangiano de dispersiĂłn. Los resultados provenientes del modelo se utilizan para la obtenciĂłn de la corriente residual que subyace a los movimientos periĂłdicos de marea. Esta corriente se relaciona con la calidad del agua, pues determina su tiempo de residencia. El modelo es forzado en la boca de la rĂa a travĂ©s de las constituyentes armĂłnicas de marea más importantes y con el agua dulce introducida en la parte interior del estuario por el rĂo Oitaven. Los resultados obtenidos muestran una circulaciĂłn en doble capa, además de una entrada principal del agua por la boca sur y una salida de Ă©sta por la boca norte.Instituto Español de OceanografĂ
Propagation Failure in Excitable Media
We study a mechanism of pulse propagation failure in excitable media where
stable traveling pulse solutions appear via a subcritical pitchfork
bifurcation. The bifurcation plays a key role in that mechanism. Small
perturbations, externally applied or from internal instabilities, may cause
pulse propagation failure (wave breakup) provided the system is close enough to
the bifurcation point. We derive relations showing how the pitchfork
bifurcation is unfolded by weak curvature or advective field perturbations and
use them to demonstrate wave breakup. We suggest that the recent observations
of wave breakup in the Belousov-Zhabotinsky reaction induced either by an
electric field or a transverse instability are manifestations of this
mechanism.Comment: 8 pages. Aric Hagberg: http://cnls.lanl.gov/~aric; Ehud
Meron:http://www.bgu.ac.il/BIDR/research/staff/meron.htm
Controlling domain patterns far from equilibrium
A high degree of control over the structure and dynamics of domain patterns
in nonequilibrium systems can be achieved by applying nonuniform external
fields near parity breaking front bifurcations. An external field with a linear
spatial profile stabilizes a propagating front at a fixed position or induces
oscillations with frequency that scales like the square root of the field
gradient. Nonmonotonic profiles produce a variety of patterns with controllable
wavelengths, domain sizes, and frequencies and phases of oscillations.Comment: Published version, 4 pages, RevTeX. More at
http://t7.lanl.gov/People/Aric
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