Phase Noise
Mostrando 13-24 de 117 artigos, teses e dissertações.
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13. Um algoritmo de segmentação de íris em tempo real / An iris segmentation algorithm in real time
Iris segmentation is one of the crucial operations involved in iris recognition. Accurate iris segmentation is fundamental for the success and precision of the subsequent feature extraction and recognition, and consequently the high performance level of the iris recognition system. Most iris segmentation approaches proposed in the literature require highly c
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 02/12/2011
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14. Influência do ciclo estral no efeito do diazepam na ansiedade e memória de ratas
Memory and anxiety are related phenomena. Several evidences suggest that anxiety is fundamental for learnining and may facilitate or impair the memory formation process depending of the context. The majority of animal studies of anxiety and fear use only males as experimental subjects, while studies with females are rare in the literature. However, the preva
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 17/05/2011
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15. ComunicaÃÃo cinÃsica do recÃm-nascido sob influÃncia do manuseio e ruidos em uma unidade neonatal / Kinesic communication of newborn related to the handling of health and noise in neonatal intensive care unit
The kinesics capture of newborns admitted to Neonatal Units (NUs) is necessary for a care based on humanization. The objective was to assess the kinesics of newborns in a NU, related to the handling of health professionals and noise produced in the Unit, according to Birdwhistell (1985). Descriptive exploratory study of quantitative approach carried out at N
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 06/05/2011
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16. Dinâmica de Partículas Auto - Propelidas
Neste trabalho, estudamos o comportamento coletivo de sistemas vivos cujos agregados formam grupos organizados tais como bandos de pássaros, rebanhos de mamíferos e cardumes de peixes. Através de simulações numéricas, modelamos o movimento coletivo de cardumes de peixes usando regras comportamentais similares áquelas propostas por Cousin et al.[23], q
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 28/02/2011
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17. Control strategies applied for reducing the vibration and torque ripple of a special Switched Reluctance Motor
Despite its robustness the Switched Reluctance Motors (SRMs) present some inconvenient drawbacks as a major torque ripple, vibration and acoustic noise when compared to other types of motors. These characteristics are usually related to factors such as the salient poles in the stator and in the rotor, the switched feeding and the control strategy imposed by
Journal of Microwaves, Optoelectronics and Electromagnetic Applications. Publicado em: 2011-06
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18. Supressão das anomalias de fase e batimentos laterais em espectros de RMN 13c obtidos com a sequência de precessão livre no estado estacionário
The Steady-State Free Precession (SSFP) sequence has been widely used in low-field and low-resolution imaging NMR experiments to increase the signal-to-noise ratio (s/n) of the signals. Here, we analyzed the Scrambled Steady State - SSS and Unscrambled Steady State - USS sequences to suppress phase anomalies and sidebands of the 13C NMR spectrum acquired in
Química Nova. Publicado em: 2010
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19. Controle de caos e saltos entre atratores em um sistema com impactos / Control of caos and basin hopping in a system with impacts
For a mechanical system, described by the impact-pair model, we studied the control of chaos by a parametric perturbation and the basin-hopping phenomeno. For this nonintegrable system, we obtained numerically the evolution of its dynamical variables for a large set of initial conditions and control parameters. For this analysis, we used phase planes, Poinca
Publicado em: 2010
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20. Projeto de filtros tipo "só-pólo" para malhas de sincronismo de fase de alta frequência. / Design of all-pole filters for high frequency phase locked loops.
The evolution of communication systems is discussed, with emphasis on optical technology. Special consideration is given to the continuous need for increasing the capacity of such systems, and the impact over future optical communication. In view of the great demands imposed over the capacity of future optical systems, an overview is presented of two recent
Publicado em: 2010
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21. Automação e otimização do projeto de um oscilador controlável por tensão para aplicações em rádio frequência. / Automation and optimization of a voltage controlled oscillator for radio frequency applications.
Nesta dissertação os conceitos e técnicas relacionadas com a automação e otimização do projeto de um oscilador controlável por tensão para aplicações de rádio frequência são apresentados. O problema de projeto do oscilador foi formulado como um problema de otimização matemática conhecido como programação geométrica. Uma abordagem à aplic
Publicado em: 2010
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22. Ruido no transporte eletronico em sistemas mesoscopicos / Noise in the electronic transport in mesoscopic systems
This dissertation describes the fundamental caracteristics of mesoscopic conductors, and the origins and properties of the sources of noise in conductors. Firstly, we describe the noise through different methods and emphasize the properties of each kind of noise. In the following, we present the scattering approach for coherent phase conductors, which allows
Publicado em: 2009
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23. Editorial
Publicado em: 2009
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24. Use of steady state free precession (SSFP) to enhance signal to noise ratio in high resolution NMR / Desenvolvimento da técnica de precessão livre no estado estacionário para aumento da razão sinal ruído em espectros de RMN de alta resolução
It was performed a detailed analysis of the advantages and disadvantages of Steady State Free Precession (SSFP) sequence for a rapid acquisition of 13C Nuclear Magnetic Resonance (NMR) spectra. The SSFP regime is obtained by the application of a pulse train with the same phase, duration and intensity, separated by a time interval (Tp) shorter than the transv
Publicado em: 2009