Transmission Channels
Mostrando 13-24 de 224 artigos, teses e dissertações.
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13. The increase of surface area of a Brazilian palygorskite clay activated with sulfuric acid solutions using a factorial design
Palygorskite is fibrous clay in which the structural tetrahedral and octahedral layers are organized in a way that structural channels are formed, leading to high surface area. However, impurities inside the channels and aggregated ones considerably reduce the available area. In order to increase the surface area, an activation treatment can be considered us
Mat. Res.. Publicado em: 21/05/2013
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14. Controle de Corrente de Spin em Pontos Quânticos na Presença de Tensões de Porta Moduladas no Tempo
Since Loss &DiVincenzo proposal to use confined electron spins in quantum dots (QDs) as a building block for qubits in solid state systems, spin-dependent transport in QDs has attracted a lot of attention. The interest for this system increased even further with the recent experimental developments to coherently control (initialization-manipulation-read out)
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 09/08/2011
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15. Design of distributed optical-fiber raman amplifiers using multi-objective particle swarm optimization
A novel method is presented to design the configuration of pumping lasers of Raman amplifiers using a multi-objective particle swarm optimizer. The goal is to obtain the pump laser wavelengths and powers that maximize the amplifier on-off gain, while maintaining the flatness of the gain over the used bandwidth. We used an algorithm called Multiple Objective
Journal of Microwaves, Optoelectronics and Electromagnetic Applications. Publicado em: 2011-12
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16. Intervenções do Estado sobre o mercado bancário e os trade-offs entre eficiência, resiliência financeira e estabilidade macroeconômica / State Interventions in banking system and the trade-offs between efficiency, financial resiliance, and macroeconomic stability
The purpose of this dissertation is to connect three banking-related concepts which are banking efficiency, financial resilience, and macroeconomic stability in a single integrated framework. It tries to understand how financial frictions settle trade-offs, whose nature and importance are investigated, and how institutional single-concept-based policies coul
Publicado em: 2011
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17. Desempenho de codigo turbo quaternario em sistemas de multiplexação por divisão de frequencias ortogonais / Performance of quaternary turbo codes in orthogonal frequency division multiplex systems
This study evaluates the performance of quaternary turbo codes, with generator matrix G = [7, 5] for the constituent convolutional codes and s-random interleaving , in an OFDM transmission system. This performance is measured in terms of bit error rate versus energy per bit to unilateral noise power spectral density ratio. The results obtained are analyzed c
Publicado em: 2010
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18. Três ensaios sobre competitividade externa e desempenho econômico na década de 2000 / Tree essays about competitiviness and economic performance in the 2000s
O objetivo central desta tese é analisar o desempenho econômico de um conjunto amplo de países sob a ótica da competitividade externa, que explicita a competitividade estrutural relativa das economias. Para isso esta tese conta com três ensaios. O primeiro ensaio constrói um índice de qualidade da pauta exportadora e qualidade da pauta importadora par
Publicado em: 2010
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19. Códigos LDPC quaternários aplicados à técnica de transmissão OFDM / Quaternary LDPC codes applied to OFDM transmission technique
This dissertation addresses the study of error correcting codes based on sparse non-binary matrices. The LDPC (Low Density Parity Check) codes constitute a efficient family of codes generated by sparse parity check matrices and it is considered as one of the classes of codes that presents the best performance in digital communications systems. LDPC codes ove
Publicado em: 2010
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20. Expressão gênica e protéica do canal de cálcio do tipo L e seu envolvimento com o mecanismo de secreção de insulina em ilhotas de langerhans de ratos submetidos à restrição protéica e suplementados com leucina / Gene and protein expression of L type calcium channel and your involvement in the mechanism of insulin secretion in islets of Langerhans of rats submitted to protein restriction and supplementation with leucine
Voltage-dependent calcium channels (CaV) are plasma membrane proteins that lead calcium, and are activated by depolarization of the same by promoting the influx of this ion, which serves as an intracellular second messenger, turning electrical signals into chemical. This process controls several intracellular events such as exocytosis, endocytosis, muscle co
Publicado em: 2010
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21. Uma avaliação dos mecanismos de trasmissão de tráfego para IPTV
The IPTV service offer is currently the main interest of many ISPs (Internet Service Providers). Such service comprises the continuous transmission, via an IP network, of TV programs structured into channels, like the open TV ou cable TV services. The goal is to reach the same quality of conventional TV (full screen, medium or high definition), adding the in
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 06/06/2009
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22. First principle calculation of potential and multi-channel transport in Fe/MgO/Fe hetero-junction
In this work we studied the behavior of multi-channel tunneling through a realistic Fe/MgO/Fe hetero-junction ab initio potential. For this purpose we obtained Fe/MgO/Fe(001) hetero-junction effective potentials using the full potential-linear augmented plane wave WIEN2k code together with the generalized gradient approximation for the exchange-correlation p
Brazilian Journal of Physics. Publicado em: 2009-04
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23. Uma Contribuicão a Estimação de Canais PLC Variantes no Tempo utilizando Sinais Pilotos
In this dissertation is discussed and analyzed the performance of pilot-assisted channel estimation techniques for OFDM (Orthogonal Frequency Division Multiplexing) modulation that is applied to data transmission through PLC (power line communications) channels. The PLC channels are modeled as linear and time-invariant (LIT), linear and time variant (LTV), a
Publicado em: 2009
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24. A crise financeira internacional no mercado de carbono: um estudo sobre os canais de transmissão
Global economic growth has promoted a broad global climate change that could jeopardize the very life as we know on the planet. Thus, it became imperative to implement policies that would help in containing the environmental devastation and climate change. For that created the Carbon Market in the Kyoto Protocol, which was ratified by most nations of the wor
Publicado em: 2009