University Nac Of La Plata

Santiago del Estero, Argentina

University Nac Of La Plata

Santiago del Estero, Argentina
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Acosta G.G.,CONICET | Leon J.F.,University of Sussex | Mayosky M.A.,University Nac Of La Plata
2010 IEEE World Congress on Computational Intelligence, WCCI 2010 - 2010 IEEE Congress on Evolutionary Computation, CEC 2010 | Year: 2010

For the construction of an autonomous robot moving in a real environment, it is necessary to count with a system for the on-line generation of trajectories. An outstanding research area to approach this issue is the evolutive robotics, that resorts to the behavior based control. In this kind of control, a complex robot's behavior can be obtained by the coordination of more simple behaviors. This emergent behavior may has multiple objectives. The present work proposes to make a brief comparison among different behavior coordination approaches. Particularly, the coordination inspired in an artificial immune system paradigm showed promising experimental results. These results were obtained over a case study in computer simulation as well as in laboratory experiments with a Khepera II microrobot. © 2010 IEEE.

Bermeo Varon L.A.,University of Valle | Bermeo Varon L.A.,Federal University of Rio de Janeiro | Caicedo E.,University of Valle | Caicedo E.,Polytechnic University of Mozambique | And 4 more authors.
Ingenieria e Investigacion | Year: 2015

In this paper particle Swarm Optimization (PSO) algorithms are applied to estimate the particle size distribution (PSD) of a colloidal system from the average PSD diameters, which are measured by multi-angle dynamic light scattering. The system is considered a nonlinear inverse problem, and for this reason the estimation procedure requires a Tikhonov regularization method. The inverse problem is solved through several PSO strategies. The evaluated PSOs are tested through three simulated examples corresponding to polystyrene (PS) latexes with different PSDs, and two experimental examples obtained by simply mixing 2 PS standards. In general, the evaluation results of the PSOs are excellent; and particularly, the PSO with the Trelea’s parameter set shows a better performance than other implemented PSOs. © 2015, Revista Ingenieria e Investigacion - Editorial Board. All Rights Reserved.

Sesto L.A.,University Nac Of La Plata | Sesto L.A.,Institute Astrofisica Of La Plata | Sesto L.A.,CONICET | Faifer F.R.,University Nac Of La Plata | And 3 more authors.
Monthly Notices of the Royal Astronomical Society | Year: 2016

This paper presents Gemini-gri' high-quality photometry for cluster candidates in the field of NGC1316 (Fornax A) as part of a study that also includes GMOS spectroscopy. A preliminary discussion of the photometric data indicates the presence of four stellar cluster populations with distinctive features in terms of age, chemical abundance and spatial distribution. Two of them seem to be the usually old (metal poor and metal rich) populations typically found in elliptical galaxies. In turn, an intermediate-age (5 Gyr) globular cluster population is the dominant component of the sample (as reported by previous papers). We also find a younger cluster population with a tentative age of ≈ 1 Gyr. © 2016 The Authors.

Bertolami M.M.M.,University Nac Of La Plata | Bertolami M.M.M.,CONICET | Althaus L.G.,University Nac Of La Plata | Althaus L.G.,CONICET | And 3 more authors.
Monthly Notices of the Royal Astronomical Society | Year: 2011

We propose a scenario for the formation of DA white dwarfs with very thin helium buffers. For these stars we explore the possible occurrence of diffusion-induced CNO-flashes during their early cooling stage. In order to obtain very thin helium buffers, we simulate the formation of low-mass remnants through an asymptotic giant branch (AGB) final/late thermal pulse (AFTP/LTP scenario). Then we calculate the consequent white dwarf cooling evolution by means of a consistent treatment of element diffusion and nuclear burning. Based on physically sound white dwarf models, we find that the range of helium buffer masses for these diffusion-induced novae to occur is significantly smaller than that predicted by the only previous study of this scenario. As a matter of fact, we find that these flashes do occur only in some low-mass (M≲ 0.6M⊙) and low-metallicity (ZZAMS≲ 0.001) remnants about 106-107yr after departing from the AGB. For these objects, we expect the luminosity to increase by about 4 orders of magnitude in less than a decade. We also show that diffusion-induced novae should display a very typical eruption light curve, with an increase of about a few magnitudes per year before reaching a maximum ofMV~-5 to -6. Our simulations show that surface abundances after the outburst are characterized by logNH/NHe~-0.15...0.6 and N > C ≳ O by mass fractions. Contrary to previous speculations we show that these events are not recurrent and do not change substantially the final H-content of the cool (DA) white dwarf. Finally, with the aid of model predictions we discuss the possibility that Nova Vul 1670 (CK Vul) and the recently proposed [WN/WC]-central stars of planetary nebulae could be observational counterparts of this diffusion-induced nova scenario. We conclude that, despite discrepancies with observations, the scenario offers one of the best available explanations for CK Vul and, with minor modifications, explains the observed properties of [WN/WC]-central stars of planetary nebulae. © 2011 The Authors Monthly Notices of the Royal Astronomical Society © 2011 RAS.

Ozafrain S.,CONICET | Roncagliolo P.A.,University Nac Of La Plata | Muravchik C.H.,University Nac Of La Plata
2015 16th Workshop on Information Processing and Control, RPIC 2015 | Year: 2015

GNSS reflectometry (GNSS-R) is a remote sensing technique. It is based on a multi-static radar structure that uses the navigation systems' satellites as transmitters, the Earth's surface as target and a receiver that can be ground located, airborne or on board a space vehicle. The reflected signal that reaches the receiver is very weak, and its characteristics depend on several factors, such as the system geometry and the state and nature of the reflecting surface. This paper analyzes the case of a receiver located in a Low Earth Orbit (LEO) satellite intended to process GPS signals reflected over the ocean surface. Scattering models for the reflected signals are used to calculate the mean power level that is expected in different geometry and sea-state scenarios. With these results, the minimum requirements for the receiver antenna are determined in order to succesfully process the reflected signals, taking a first step on the way to design a complete GNSS-R receiver. © 2015 IEEE.

Fernandez-Michelli J.I.,CONICET | Areta J.A.,CONICET | Hurtado M.,CONICET | Muravchik C.H.,University Nac Of La Plata
2015 16th Workshop on Information Processing and Control, RPIC 2015 | Year: 2015

We propose a polarimetric SAR image classification method using the Expectation-Maximization (EM) algorithm. It is a semi-supervised algorithm with random initialization that only requires the number of clases to be identified as initial information. We apply the proposed algorithm to simulated and real Multilook Complex (MLC) polarimetric data, assuming a G0 p mixture model. The classification performance is evaluated by means of the confusion matrix and the kappa index. Finally, we compare the results to those obtained by other authors via SEM (Stochastic EM) method using the same model and data set. © 2015 IEEE.

Iglesias O.A.,University Nac Of La Plata | Soto J.D.,University Nac Of La Plata | Paniagua C.N.,University Nac Of La Plata
Informacion Tecnologica | Year: 2012

Some modules have been developed for an open code process simulator, Sim42, accessible through the Web. The objective is the consideration of the design variables in the optimum structuring of industrial processes, in the teaching of Chemical Engineering. The simulator must be able to: a) estimating the investment in equipments, the costs of services and inputs and the revenues for sale and b) managing an optimization method for non lineal restricted problems. Since both facilities do not exist in Sim42 new modules were added to the available code, as well as others ones that complete the analysis. The developments are applied to the simulation, analysis and optimization of a Linde cycle to liquefy a methane stream. It is conclude that having an open-source simulator that allows adapting its performance to the requirements of the concepts to be conveyed is highly convenient.

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