El dinero : funciones, liquidez, formas y creación

Fil: Blondeau, René D. Universidad de Buenos Aires. Facultad de Derecho. Cátedra de Política Económica Argentina. Buenos Aires, Argentin

Raising the noise to improve performance in optimal processing

We formulate, in general terms, the classical theory of optimal detection and optimal estimation of signal in noise. In this framework, we exhibit specific examples of optimal detectors and optimal estimators endowed with a performance which can be improved by injecting more noise. From this proof of feasibility by examples, we suggest a general mechanism by which noise improvement of optimal processing, although seemingly paradoxical, may indeed occur. Beyond specific examples, this leads us to the formulation of open problems concerning the general characterization, including the conditions of formal feasibility and of practical realizability, of such situations of optimal processing improved by noise

Non-Gaussian noise benefits for coherent detection of narrowband weak signal

Non-Gaussian noise benefits for coherent detection of narrowband weak signal

Double-maximum enhancement of signal-to-noise ratio gain via stochastic resonance and vibrational resonance

Double-maximum enhancement of signal-to-noise ratio gain via stochastic resonance and vibrational resonance

Optical coherence of a scalar wave influenced by first-order and second-order statistics of its random phase

We analyze a simple model of a scalar optical wave with partial coherence. The model is devised to describe the influence on the coherence of the wave, of the statistical properties of its random phase, including both the second-order statistics (phase correlation) — which is classic, but also the first-order statistics (phase distribution) — which is nonclassic. Expectedly, upon increasing the disorder of the fluctuating phase through a reduction of its correlation duration, the model shows that the coherence of the wave is always reduced. By contrast, upon increasing the disorder of the fluctuating phase through an increase of its dispersion, the model reveals that the coherence of the wave can sometimes be enhanced. This beneficial consequence of an increase in disorder is related to the phenomenon of stochastic resonance or improvement by noise in signal processing

Analyse 3D de microstructures de graines en microtomographie par rayons X

Analyse 3D de microstructures de graines en microtomographie par rayons X

Tsallis entropy measure of noise-aided information transmission in a binary channel

Noise-aided information transmission via stochastic resonance is shown and analyzed in a binary channel by means of information measures based on the Tsallis entropy. The analysis extends the classic reference of binary information transmission based on the Shannon entropy, and also parallels a recent study based on the Rényi entropy. The conditions for a maximally pronounced stochastic resonance identify optimal Tsallis measures. The study involves a correspondence between Tsallis and Rényi information measures, specially relevant to the characterization of stochastic resonance, and establishing that for such effects identical properties are shared in common by both Tsallis and Rényi measures

Modèle stochastique et représentation par graphe pour le suivi spatio-temporel de pathogènes à la surface de feuilles par imagerie

Modèle stochastique et représentation par graphe pour le suivi spatio-temporel de pathogènes à la surface de feuilles par imagerie

Exploiting the speckle noise for compressive imaging

An optical setup is proposed for the implementation of compressive sensing with coherent images. This setup specifically exploits the natural multiplicative action of speckle noise occurring with coherent light, in order to optically realize the essential step in compressive sensing which is the multiplication with known random patterns of the image to be acquired. In the test of the implementation, we specifically examine the impact of several departures, that exist in practice, from the ideal conditions of a pure multiplicative action of the speckle. In such practical realistic conditions, we assess the feasibility, performance and robustness of the optical scheme of compressive sensing. (C) 2011 Elsevier B.V. All rights reserved