12,623 research outputs found
Intertemporal and Spatial Location of Disposal Facilities
Optimal capacity and location of a sequence of land.lls are studied, and the interactions between both decisions are pointed out.The decision capacity has some spatial implications, because it a.ects the feasible region for the rest of land.lls, and some temporal implications, because the capacity determines the lifetime of the land.ll and hence the instant of time where next land.lls will need to be constructed.Some general mathematical properties of the solution are provided and interpreted from an economic point of view.The resulting problem turns out to be no convex and therefore it can not be solved by conventional optimization techniques.Some global optimization methods are used to solve the problem in a particular case, in order to illustrate the behavior of the solution depending on parameter values.Landfilling;Optimal Capacity;Optimal Location;Global Optimization
Quantum Isotropization of the Universe
We consider minisuperspace models constituted of Bianchi I geometries with a
free massless scalar field. The classical solutions are always singular (with
the trivial exception of flat space-time), and always anisotropic once they
begin anisotropic. When quantizing the system, we obtain the Wheeler-DeWitt
equation as a four-dimensional massless Klein-Gordon equation. We show that
there are plenty of quantum states whose corresponding bohmian trajectories may
be non-singular and/or presenting large isotropic phases, even if they begin
anisotropic, due to quantum gravitational effects. As a specific example, we
exhibit field plots of bohmian trajectories for the case of gaussian
superpositions of plane wave solutions of the Wheeler-DeWitt equation which
have those properties. These conclusions are valid even in the absence of the
scalar field.Comment: 10 pages, RevTeX, 3 Postscript figures, uses graficx.st
Exploiting Prior Knowledge in Compressed Sensing Wireless ECG Systems
Recent results in telecardiology show that compressed sensing (CS) is a
promising tool to lower energy consumption in wireless body area networks for
electrocardiogram (ECG) monitoring. However, the performance of current
CS-based algorithms, in terms of compression rate and reconstruction quality of
the ECG, still falls short of the performance attained by state-of-the-art
wavelet based algorithms. In this paper, we propose to exploit the structure of
the wavelet representation of the ECG signal to boost the performance of
CS-based methods for compression and reconstruction of ECG signals. More
precisely, we incorporate prior information about the wavelet dependencies
across scales into the reconstruction algorithms and exploit the high fraction
of common support of the wavelet coefficients of consecutive ECG segments.
Experimental results utilizing the MIT-BIH Arrhythmia Database show that
significant performance gains, in terms of compression rate and reconstruction
quality, can be obtained by the proposed algorithms compared to current
CS-based methods.Comment: Accepted for publication at IEEE Journal of Biomedical and Health
Informatic
¿En los orígenes de una burguesía agraria o la consolidación de una economía de renta? La formación de un patrimonio rural en la Galicia sudoriental, 1740-1850
[Resumen]Este trabajo es una reflexión que intenta
dar respuesta a una serie de interrogantes: ¿Economía de renta y, por consiguiente,
racionalidad de Antiguo Régimen, o también primeros pasos hacia la asunción
de una racionalidad capitalista en el dominio y explotación de la tierra a cargo de una
burguesía ascendiente? La vitalidad mostrada por la familia objeto de estudio y lo diversificado
de su estrategia sugieren en principio la emergencia de una burguesía agraria. Faltan,
no obstante, elementos que permitan verificar su presencia. No parece que nuestra familia
explote directamente sus tierras, ni siquiera en parte, con trabajo asalariado.
Tampoco se destaca por la introducción de innovaciones agrícolas y, por más que destine
sus excedentes al mercado, la preferencia por cultivos tradicionales y seguros diseña
un perfil más próximo al del clásico rentista que al del burgués, no digamos al «empresario
agrario». La configuración geográfica y socioeconómica de la comarca de
Manzaneda, desprovista de actividades mercantiles o industriales de relieve, mal comunicada,
con débil densidad demográfica y alejada de núcleos urbanos importantes,
añade dificultad a la hipótesis de un despuntar del capitalismo agrario
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