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De Melo V.V.,Federal University of Sao Paulo | Carosio G.L.C.,Brazilian Technological Institute of Aeronautics
Expert Systems with Applications | Year: 2013

Several constrained and unconstrained optimization problems have been adequately solved over the years thanks to advances in the metaheuristics area. In the last decades, different metaheuristics have been proposed employing new ideas, and hybrid algorithms that improve the original metaheuristics have been developed. One of the most successfully employed metaheuristics is the Differential Evolution. In this paper it is proposed a Multi-View Differential Evolution algorithm (MVDE) in which several mutation strategies are applied to the current population to generate different views at each iteration. The views are then merged according to the winner-takes-all paradigm, resulting in automatic exploration/exploitation balance. MVDE was tested to solve a set of well-known constrained engineering design problems and the obtained results were compared to those from many state-of-The-art metaheuristics. Results show that MVDE was very competitive in the considered problems, largely outperforming several of the compared algorithms. © 2012 Elsevier Ltd. All rights reserved. Source

Frederico T.,Brazilian Technological Institute of Aeronautics
Few-Body Systems | Year: 2014

The theoretical few-body aspects associated with universal properties of weakly-bound neutron-rich light nuclei close to the drip line will be reviewed briefly, considering recent theoretical and experimental works. We will address low-energy properties of the one- and two-neutron halo of light exotic nuclei, which are dominated by s-wave short-range two-body interactions. In view of recent experiments with light neutron-rich nuclei, we will discuss properties of exotic nuclei as 11Li, 14Be, 20C and 22C, within a three-bodyneutron-neutron-core model. Particular emphasis will be given to model independent properties associated to halo neutrons, which obey universal scaling laws. We discuss how the scaling laws for the s-wave observables of two-neutron halo will be identified with limit-cycles and Thomas-Efimov effect in a zero-range three-body model. © 2014 Springer-Verlag Wien. Source

Dias S.S.,Embraer SA | Bruno M.G.S.,Brazilian Technological Institute of Aeronautics
IEEE Transactions on Signal Processing | Year: 2013

This paper introduces new cooperative particle filter algorithms for tracking emitters using received-signal strength (RSS) measurements. In the studied scenario, multiple RSS sensors passively observe different attenuated and noisy versions of the same signal originating from a moving emitter and cooperate to estimate the emitter state. Assuming unknown sensor noise variances, we derive an exact decentralized implementation of the centralized particle filter solution for this problem in a fully connected network. Next, assuming only local internode communication, we introduce two fully distributed consensus-based solutions to the cooperative tracking problem using respectively average consensus iterations and a novel ordered minimum consensus approach. In the latter case, we are able to reproduce the exact centralized solution in a finite number of consensus iterations. To further reduce the communication cost, we derive in the sequel a new suboptimal algorithm which employs suitable parametric approximations to summarize messages that are broadcast over the network. Numerical simulations with small-scale networks show that the proposed approximation leads to a modest degradation in performance, but with much lower communication overhead. Finally, we introduce a second alternative low communication cost algorithm based on random information dissemination. © 1991-2012 IEEE. Source

Moraes P.H.R.S.,Brazilian Technological Institute of Aeronautics
International Journal of Theoretical Physics | Year: 2016

In this work I present a generalization of f(R, T) gravity, by allowing the speed of light to vary. Cosmological solutions are presented for matter and radiation-dominated universes, the former allowing the universe expansion to accelerate while the latter contemplating a possible alternative to inflationary scenario. Remarkably, standard gravity is always retrieved for a special case of f(R, T). © 2015, Springer Science+Business Media New York. Source

de Lemos M.J.S.,Brazilian Technological Institute of Aeronautics
International Communications in Heat and Mass Transfer | Year: 2010

The objective of this paper is to present an extension of a simplified reaction kinetics model that, combined with a thermo-mechanical closure, entails a full-generalized turbulent combustion model for flow in porous media. In this model, one explicitly considers the intra-pore levels of turbulent kinetic energy. Transport equations are written in their time-and-volume-averaged form and a volume-based statistical turbulence model is applied to simulate turbulence generation due to the porous matrix. The rate of fuel consumption is described by an Arrhenius expression involving the product of the fuel and oxidant mass fractions. These mass fractions are double decomposed in time and space and, after applying simultaneous time-and-volume integration operations to them, distinct terms arise, which are here associated with the mechanisms of dispersion and turbulence. Modeling of these extra terms remains an open question and the derivations herein might motivate further development of models for turbulent combustion in porous media. © 2010 Elsevier Ltd. All rights reserved. Source

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