Spread Spectrum
Mostrando 13-24 de 116 artigos, teses e dissertações.
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13. Vibroacustografia na avaliação tridimensional de artroplastia total de quadril / Vibro-acoustography in the tridimensional evaluation of total hip arthroplasty
Vibro-acoustography (VA) is a high lateral resolution (<0.7 mm), speckle-free, non- ionizing and non-invasive image based on the nonlinear combination phenomenon of ultrasound waves (MHz) that generates a narrow focus region of low frequency (kHz). In this work, we propose a VA-based tridimensional evaluation of the exposed area of implants, after total hip
Publicado em: 2011
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14. Spread of phosphine resistance among brazilian populations of three species of stored product insects
The resistance to fumigant insecticides in stored-products insects is often recorded. Several factors influence the evolution of insecticide resistance. Among these, the frequency of applications and the migration of resistant populations are of primary importance for the stored-product insects. The aim of this study was to characterize the spectrum and inve
Neotropical Entomology. Publicado em: 2010-02
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15. Esteganografia e marcas d'água : a busca por algoritmos robustos
O ser humano sempre sentiu necessidade de privacidade. Em um mundo que a informação pode ser vista e/ou interceptada por todos, métodos que garantem a privacidade de nossa comunicação são criados a todo momento. Um dos ramos mais explorados é chamado de Esteganografia. Neste trabalho de conclusão iremos demonstrar dois algoritmos de Esteganografia pa
Publicado em: 2010
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16. Geradores de seqüências pseudoaleatórias usando caos em sistemas de espalhamento espectral
Spread sprectrum is a modulation technique that uses a binary sequence to spread an information signal in frequency domain. Conventionally, the process of spreading uses pseudo-random sequences created by shift-registers. However, sequences created using chaotic signals can also be employed because they have compatible spectral and autocorrelation properties
Publicado em: 2009
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17. Prevalência de beta-lactamases de amplo espectro e metilases RNAr 16S em isolados clínicos de Pseudomonas aeruginosa multirresistentes recuperados em diferentes hospitais de São Paulo / Prevalence of Extended-spectrum beta-lactamase and 16S rRNA methylases in clinical isolates of multidrug-resistant Pseudomonas aeruginosa recovered from differents hospitals in São Paulo
Introduction and aim: The production of extended-spectrum beta-lactamases (ESBLs) has been restricted to Klebsiella spp. and Escherichia coli, being associated with high rates of resistance, morbidity and mortality. Since genetic determinants for ESBLs (blaESBL genes) are mediated by plasmids, the spread to other medical important species is considered an ep
Publicado em: 2009
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18. Sistema de esteganografia em áudio digital que utiliza técnicas eficientes de inserção de dados
Esta dissertação apresenta uma melhoria feita em uma técnica de esteganografia para áudio que emprega espalhamento espectral (spread spectrum), o que permite que se insira muito mais informação no sinal hospedeiro, sem que com isso haja degradação da qualidade perceptual, utilizando três métodos diferentes de compressão de dados sem perdas nas fon
Publicado em: 2009
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19. Wireless network in the process industries: opportunities and challenges. / Redes sem fio na indústria de processos: oportunidades e desafios.
The wireless data transmissions are part of our daily lives. The wireless network is the technology that has been most developed in the beginning of the 21st century and this evolution allowed the industry to start considering the wireless technology as a viable option to its reality. Due to that, the aim of this paperwork is to study the wireless instrument
Publicado em: 2009
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20. Aproximações entre biologia, biopolítica e bioarte: um ensaio sobre a biocontemporaneidade / Approximations among biology, biopolitics and bioart: an essay on biocontemporaneity.
This paper aims at reflecting on some implications around the contemporary biological discourse through the analysis of how some concepts in the field of biological sciences particularly species and genes spread through the social body, associating with certain modes of subjectivation. The guiding hypothesis of the present study is that the non-explicitation
Publicado em: 2009
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21. Epidemiologia molecular de Escherichia coli e Klebsiella spp produtoras de beta-lactamase de espectro ampliado
The extended-spectrum beta-lactamases (ESBL) represent an important mechanism of resistance to beta-lactam antibiotics. Such enzymes have spread among members of the Enterobacteriaceae family, which are responsible for infections related to health care, particularly nosocomial infections. Objectives: (a) To determine the prevalence of ESBL producing Escheric
Publicado em: 2009
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22. Evaluation of the spread sequences selection algorithm over frequency selective fading channels with error correcting codes / Avaliação do algoritmo de busca de sequencias de espalhamento em canais com desvanecimento seletivo em frequencia com codigos corretores de erros
The performance of wireless communication systems that use the multiple access code division technique, CDMA, is interference-limited. A sequence selection algorithm allows a reduction in the mean interference of the system. In the standards like CDMA2000 and WCDMA no algorithm is defined for choosing the sequences. For this reason, in this dissertation we e
Publicado em: 2008
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23. Banco de filtros e wavelets sobre corpos finitos
Filter banks and wavelets are tools of Engineering, dened over complex elds, with many applications. This dissertation introduces the theory of lter banks and wavelets dened over nite elds, over cyclical and noncyclical structures. The problem of dening two-channel lter banks and wavelet decompositions over elds of characteristic two was solved, thereby prov
Publicado em: 2008
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24. Implementação de espalhamento espectral por seqüência direta
O presente trabalho tem como objetivo a descrição e apresentação dos resultados obtidos através de simulações e implementação da técnica de modulação por espalhamento de espectro (Spread Spectrum). Maior ênfase será dada à técnica de espalhamento por seqüência direta (DSSS), dada a larga utilização nos sistemas de comunicação correnteme
Publicado em: 2007