Ray Tracing
Mostrando 13-24 de 49 artigos, teses e dissertações.
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13. APLICAÇÃO DO MÉTODO DAS DIFERENÇAS FINITAS NO DOMÍNIO DO TEMPO NA ANÁLISE DE COBERTURA EM AMBIENTES INTERIORES / APPLICATION OF FINITE DIFFERENCE TIME DOMAIN IN THE ANALYSIS OF INDOOR COVERAGE
The growing interest in broadband wireless local networks and high trans- mission rates requires an increasingly reliable modeling of radio propagation channels, specially for indoor scenarios. The use of optical methods of elec- tromagnetic field tracking along (ray) trajectories between transmission and observation points, via high-frequency analysis of sc
Publicado em: 2008
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14. Padronização dos Radionuclídeos 201Tl e 55Fe em sistema de coincidências 4(PC)-NaI(Tl) / STANDARDIZATION OF 201Tl AND 55Fe RADIONUCLIDES IN A 4(PC)-NaI(Tl) COINCIDENCE SYSTEM
In the present work the procedure for the standardization of radionuclides using the 4(PC)-NaI(Tl) coincidence system was developed. The radionuclides selected were 201Tl, used in nuclear medicine, and 55Fe primary standard source, used for x-ray spectrometers calibration. The 4(PC)-NaI(Tl) is composed of a 4 proportional counter operated at 0.1MPa coupled t
Publicado em: 2008
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15. Simulation of optical and physiological phenomena of the human vision / Simulação de fenômenos óticos e fisiológicos do sistema de visão humana
The increase in performance of the modern computers has driven scientific work in the areas of computer simulation. Many authors use in their research commercial tools that use embedding algorithms, which sources are not provided, and it makes harder and sometimes impossible, the development of novel theories or experiments. This work explores this gap left
Publicado em: 2008
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16. Hybrid method for numerical simulation of room acoustics with auralization: part 1 - theoretical and numerical aspects
A new hybrid simulation method for room acoustics is presented. It is grounded on two well known numerical simulation techniques for room acoustics. The hybrid method takes geometric acoustics for granted and uses an improved version of the classical ray-tracing technique for computing the specular reflections and a slightly modified energy transition method
Journal of the Brazilian Society of Mechanical Sciences and Engineering. Publicado em: 2007-06
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17. Interactive GPU-assisted ray tracing. / Traçado de raios interativo assistido pela unidade de processamento gráfico.
Known by its high computational cost and by the high quality rendered imagens, ray tracing has been most recently explored by the scientific community in researches for interactive and constant frame rate. Aiming for a new way for optimizing ray tracing, a new approach called GPU-assisted ray tracing is defined in this work. Its objective is to be a first st
Publicado em: 2007
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18. Double diffraction white light imaging without intermediary elements / Imagem por dupla difração com luz branca sem elementos intermediarios
We present the analysis of the formation of images by diffractive elements using white light by performing ray-tracing through main directions. The first system we describe is composed of two diffraction gratings and a slit, the second by two bi-dimensional spiral elements and a hole aperture, generating ortoscopic (natural relief) images. From this we had f
Publicado em: 2007
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19. Uma análise vetorial de propagação UHF e de microondas em áreas urbanas e rurais usando teoria do traçado do raio / A vectorial analysis of uhf and microwave propagation in urban and rural areas using ray-tracing theory
Este trabalho apresenta modelos de propagação para áreas urbanas, suburbanas e rurais. É apresentada uma análise vetorial do modelo geométrico de dois raios para antenas elevadas, bem como análises vetoriais dos modelos de guia de ondas de rua plano e tridimensional. Para todos, um dipolo ideal é utilizado como antena transmissora. O modelo geométri
Publicado em: 2007
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20. RAY TRACING ANALYSIS OF THE EFFECTS OF PROPAGATION ON MULTIPLE-INPUT MULTIPLE-OUTPUT (MIMO) CHANNELS / ANÁLISE DOS EFEITOS DA PROPAGAÇÃO EM CANAIS COM MÚLTIPLAS ENTRADAS E MÚLTIPLAS SAÍDAS (MIMO) COM BASE NO TRAÇADO DE RAIOS
A ray tracing model based on the method of images has been applied to study the propagation of radio waves in the regions of Copacabana and Ipanema in Rio de Janeiro. In such highly urbanized environments, it can be realistically assumed that propagation is restricted to a horizontal section of the street canyons characterized by the blocks of buildings. Sev
Publicado em: 2005
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21. Modelo 2,5D de predição de propagação para ambientes interiores utilizando o método do traçado de raios
A 2.5D ray-tracing propagation model is proposed to predict radio loss in indoor environment. Specifically, we opted for the Shooting and Bouncing Rays (SBR) method, together with the Geometrieal Theory of Diffrartion (GTD). Besides the line-of-sight propagation (LOS), we consider that the radio waves may experience reflection, refraction, and diffraction (N
Publicado em: 2005
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22. APPLICATION OF COMPUTATIONALLY-INTENSIVE PROPAGATION MODELS TO THE PREDICTION OF PATH LOSSES DUE TO MOUNTAINOUS TERRAIN IN THE VHF FREQUENCY BAND / APLICAÇÃO DE MODELOS COMPUTACIONALMENTE INTENSIVOS NA PREVISÃO DAS PERDAS DE PROPAGAÇÃO DEVIDAS A TERRENOS IRREGULARES NA FAIXA DE VHF
Os efeitos da difração na propagação de ondas de rádio sobre terreno irregular em VHF e outras bandas a ser usado por futuras aplicações da TV digital são normalmente estimados usando um dos muitos modelos clássicos. Nesta dissertação é feita uma comparação dos erros cometidos na previsão do sinal recebido por três modelos de propagação com
Publicado em: 2005
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23. Standardization of Ca-45 radioactive solution by tracing method
The procedure followed by the Laboratório de Metrologia Nuclear (LMN) at the IPEN, in São Paulo, for the standardization of the 45Ca is described. The activity measurement was carried out in a 4pb-gamma coincidence system, by the tracing method. The radionuclide chosen as the beta-gamma emitting tracer nuclide was 60Co because of i
Brazilian Journal of Physics. Publicado em: 2004-09
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24. Study of generation and propagation of the atmospheric gravity waves / Estudos de geração e propagação de ondas de gravidade atmosféricas
In this study the generation and propagation of the atmospheric gravity waves were investigated. The gravity waves in the mesopause region were observed by airglow all sky imaging technique at Cachoeira Paulista (23°S, 45°W), near tropic of Capricorn, and at São João do Cariri (7°S, 36°W), in the equatorial region. A reverse ray tracing method was test
Publicado em: 2004