Prediction Of Attenuation
Mostrando 1-12 de 21 artigos, teses e dissertações.
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1. Vegetation Image as Bayesian Predictor for Radio Propagation in Complex Environments Using Unscented Transform
Abstract Vegetation is considered a complex environment for analysis of scattering and attenuation in radio propagation phenomena. Satellite image processing can improve planning of radio systems with a vegetation attenuation predictor. In this research, the prediction is based on the correlation of more than 56% between RGB pixel values and vegetation atten
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2018-06
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2. Comparing blast-induced ground vibration models using ANN and empirical geomechanical relationships
Abstract Blasting remains as an economical and reliable excavation technique, but there are some environmental shortcomings such as the control of blast-induced vibration. The impacts of vibration over surrounding communities in a blast area have been investigated for decades and researchers have been using a myriad of empirical predictive attenuation equati
REM, Int. Eng. J.. Publicado em: 2018-03
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3. Statistical Evaluation of Measured Rain Attenuation in Tropical Climate and Comparison with Prediction Models
Abstract Substantial modifications have been made to the expressions for calculating distance factor and extrapolation techniques in the latest ITU-R P.530-14. However, its performance has not been rigorously evaluated in the tropical and equatorial climates. In this article, the new ITU-R method and three prediction models are validated using measurement da
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2016-06
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4. Modified rain attenuation prediction method considering the effect of wind direction
The method currently recommended by the ITU-R for the prediction of rain attenuation in terrestrial line-of sight links considers an equivalent path length over which the rain intensity is assumed to be constant. In other methods, the spatial and temporal variations of the rainfall rate along the path are characterized by an effective rainfall rate that is d
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2014-12
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5. Unified method for the prediction of rain attenuation in satellite and terrestrial links
In this paper, a semi-empirical method for the prediction of rain attenuation in slant paths and terrestrial links is proposed. The method uses the same simplified model of equivalent rain cell that is the basis for the ITU-R rain attenuation prediction methods but, additionally, the concept of an effective rain rate is introduced. This allows the use of the
Journal of Microwaves, Optoelectronics and Electromagnetic Applications. Publicado em: 2012-06
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6. AnÃlise de atenuaÃÃo de sinal em ambientes indoor usando lÃgica nebulosa / Analysis of signal attenuation for Indoor Environments using Fuzzy Logic
Due to the increasing demand for services related to wireless networks, such as video, voice and video conferencing and to the concern of telecommunications companies to meet this demand efficiently, the planning of a wireless link becomes very important. Since the propagation of a signal over a wireless network is not driven, it can suffer attenuation cause
Publicado em: 2009
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7. Estudo sistemático do freamento de íons pesados em sólidos no regime de baixas velocidades / Systematic study of heavy ions stopping in solids at the low velocity regime
The energy loss of ions in materials is an important issue not only because of its direct applications on material analysis techniques, but also for the understanding of the interactions. Accurate knowledge of heavy ion stopping power at low energies is necessary in materials science as well as in basic physics, e. g. in the Doppler Shift Attenuation Method
Publicado em: 2009
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8. Distribuição vertical e sazonal da comunidade fitoplanctônica em dois reservatórios eutróficos do Estado de Pernambuco
The dynamics of the phytoplankton community in aquatic ecosystems provides considerable diagnostic information and serves as a sensitive tool for the indication of environmental changes, enabling the prediction of changes in any body of water. The vertical distribution of these organisms in eutrophic reservoirs remains an under-explored field of study, but i
Publicado em: 2009
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9. JOINT EFFECT OF RAIN ATTENUATION AND INTERFERENCE IN THE ESTIMATION OF FIXED SERVICE LINK PERFORMANCE PARAMETERS / CONSIDERAÇÃO CONJUNTA DA ATENUAÇÃO POR CHUVAS E DE INTERFERÊNCIAS EXTERNAS NA ESTIMAÇÃO DOS PARÂMETROS DE DESEMPENHO DE ENLACES DIGITAIS TERRESTRES
Recomendações específicas da União Internacional de Telecomunicações estabelecem objetivos de desempenho para enlaces de comunicações digitais terrestres. Esses objetivos impôem restrições a parâmetros tais como a taxa de segundos errados, a taxa de segundos severamente errados e a taxa de erro de bloco de fundo, a partir dos quais se define a di
Publicado em: 2008
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10. A methodology for noise prediction of turbofan engines.
A computional model is developed for prediction of noise emission from na existing or new turbofan engine. This model allows the simulation of noise generation from high bypass ratio turbofan engines, appropriate for use with computational programs for gas turbine performance developed at ITA. Analytical and empirical methods are used for spectrum shape, spe
Publicado em: 2006
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11. Muffler modeling by transfer matrix method and experimental verification
Mufflers are widely used for exhaust noise attenuation in vehicles and machinery. Recent advances in modeling procedures for accurate performance prediction have led to the development of modeling methods for practical muffler components in commercial design. Muffler designers need simple and fast modeling tools, especially in the preliminary design evaluati
Journal of the Brazilian Society of Mechanical Sciences and Engineering. Publicado em: 2005-06
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12. PREDIÇÃO DA INDISPONIBILIDADE POR CHUVAS EM REDES VSAT NO BRASIL / RAIN UNAVAILABILITY PREDICTION ON VSAT NETWORKS IN BRAZIL
In satellite communication, the Brazilians rains distributions are presented like limited factor in the viability analyze of VSAT networks (Very Small Aperture Terminal) in the bands Ka and Ku. The aim of the work is analyze the unavailable caused by VSAT rains with star topology used in Brazil to some kinds of service, like telephone and data transmission a
Publicado em: 2004