In this article, a new approach to the problem of indoor navigation based on ultrasonic sensors is presented, where artificial neural networks (ANN) are used to estimate the position and orientation of a mobile robot. This approach proposes the use of three Radial Basis Function (RBF) Networks, where environment maps from an ultrasonic sensor and maps synthetically generated are used to estimate the robot localization. The mobile robot is mainly characterized by its real time operation based on the Matlab/Simulink environment, where the whole necessary tasks for an autonomous navigation are done in a hierarchical and easy reprogramming way. Finally, practical results of real time navigation related to robot localization in a known indoor environment are shown.

A kinetic approach to the problem of wave propagation in dusty plasmas, which takes into account the variation of the charge of the dust particles due to inelastic collisions with electrons and ions, is utilized as a starting point for the development of a new formulation, which writes the components of the dielectric tensor in terms of a finite and an infinite series, containing all effects of harmonics and Larmor radius. The formulation is quite general and valid for the whole range of frequencies above the plasma frequency of the dust particles, which were assumed motionless. The formulation is employed to the study of electrostatic waves propagating along the direction of the ambient magnetic field, in the case for which ions and electrons are described by Maxwellian distributions. The results obtained in a numerical analysis corroborate previous analysis, about the important role played by the inelastic collisions between electrons and ions and the dust particles, particularly on the imaginary part of the dispersion relation. The numerical analysis also show that additional terms in the components of the dielectric tensor, which are entirely due these inelastic collisions, play a very minor role in the case of electrostatic waves, under the conditions considered in the present analysis.

O objetivo desse trabalho é trazer para um foco mais preciso as relações da moralidade com a sensibilidade humana no pensamento de Kant. Visto que, por um lado, a vontade humana é uma “faculdade de desejar” que está necessariamente vinculada ao prazer e desprazer, e que, por outro lado, a tarefa filosófica em relação ao tema é concebida como “metafísica”, isto é, de abordagem a priori, tem-se que os dados do problema não sugerem uma solução fácil. A teoria kantiana do respeito – o “sentimento necessário” – como o móbil da razão pura prática é o locus classicus quando se busca essa solução. A lei moral tem um efeito necessário sobre a sensibilidade de agentes como nós. Nossa agência, inicialmente, se orienta naturalmente pelo amor-próprio, e inevitavelmente sucumbe à arrogância como concepção de valor quando erige aquele amor como fonte de valor absoluto. A lei moral causa dano irreparável à arrogância, produzindo assim necessariamente a dor presente no respeito a essa lei. Esse modelo de visão das relações que nos interessam parece estar presente também, em traços gerais, na teoria kantiana das “predisposições morais”, sem que, nesse caso, Kant se enderece ao problema da motivação moral, mas, alternativamente, procure oferecer uma visão mais ampla da fenomenologia da experiência moral de agentes como nós.

In the present article, the classic problem of nonlinear frequency shifts of electrostatic plasma eigenmodes in an unmagnetized plasma (i.e., the Langmuir and ion-acoustic waves) is revisited. In the standard literature, only the frequency shift of Langmuir waves by the finite-amplitude Langmuir waves themselves is usually treated. In the present approach, the discussion is generalized to include the ion-sound waves. The significance of the present article is that the analytical approach employed in the present discussion can be utilized to resolve certain apparently singular terms in the induced scattering coefficients of the wave kinetic equations. The detailed discussion of such a problem will be reported in a forthcoming article.

Nonlinear interactions of tenuous electron beam, background, unmagnetized plasma, and self-consistently generated Langmuir and ion-sound waves are analyzed in the framework of plasma weak turbulence kinetic theory. Full numerical solutions of the complete weak turbulence equations are obtained for the first time, which show the familiar plateau formation in the electron beam distribution and concomitant quasi-saturation of primary Langmuir waves, followed by fully nonlinear processes which include three-wave decay and induced-scattering processes. A detailed analysis reveals that the scattering off ions is an important nonlinear process which leads to prominent backscattered and long-wavelength Langmuir wave components. However, it is found that the decay process is also important, and that the nonlinear development of weak Langmuir turbulence critically depends on the initial conditions. Special attention is paid to the electron-to-ion temperature ratio, Te/Ti, and the initial perturbation level. It is found that higher values of Te/Ti promote the generation of backscattered Langmuir wave component, and that a higher initial wave intensity suppresses the backscattered component while significantly enhancing the long-wavelength Langmuir wave component.