• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 648
  • 212
  • 102
  • 98
  • 78
  • 68
  • 29
  • 22
  • 20
  • 18
  • 17
  • 16
  • 10
  • 9
  • 9
  • Tagged with
  • 1568
  • 123
  • 112
  • 107
  • 105
  • 99
  • 91
  • 89
  • 74
  • 71
  • 70
  • 68
  • 68
  • 67
  • 66
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
271

Medi??o de Qualidade de voz em Wireless utilizando os codecs G711,G729,G723 e GSM / Measurement of quality of a wireless voice codecs using the G711, G729, G723 and GSM

Almeida, Adenilson Boccato de 18 December 2008 (has links)
Made available in DSpace on 2016-04-04T18:31:26Z (GMT). No. of bitstreams: 1 Adenilson Boccato de Almeida.pdf: 2733171 bytes, checksum: 5b2d37bdad4b16ff26ccb172bbd6fbfc (MD5) Previous issue date: 2008-12-18 / This dissertation examines the quality of the transmission of VoIP (Voice over IP) in wireless LAN (Local Area Network Wireless). To achieve this objective tests were performed on the bench using voice codecs G729, G711, G723 and GSM analyzing characteristics of delay and loss of packets. The paper presents results that indicate the effect of the phenomena of instability of wireless networks in the performance of VoIP. These variations show significant changes in the quality of voice depending on the used environment and the distance between the transmitter and receiver. / Esta disserta??o analisa a qualidade da transmiss?o do VoIP (Voz sobre IP) em rede WLAN (Wireless Local ?rea Network). Para atingir esse objetivo foram realizados testes em bancada utilizando os codecs de voz G729, G711, G723 e GSM analisando suas caracter?sticas de atraso e perda de pacotes. O trabalho apresenta resultados que indicam o efeito dos fen?menos de instabilidade das redes sem fio no desempenho do VoIP. Essas varia??es revelam altera??es significativas na qualidade da voz em fun??o do ambiente utilizado e da dist?ncia entre o emissor e receptor.
272

Ensaio em família: Bem vindos de novo São Paulo / -

Yoshisaki, Marcos Vinicius 27 September 2018 (has links)
A dissertação investiga possibilidades formais de articulação entre universos pessoais e processos históricos no campo da realização documentária em primeira pessoa. O ponto de partida são materiais e procedimentos advindos de um documentário de longa-metragem que atualmente desenvolvo, intitulado Bem vindos de novo. O filme aborda as experiências da minha família na imigração de nipo-brasileiros para o Japão, conhecida como \"fenômeno decasségui\". Nele, busco articular as experiências pessoais e familiares com aspectos mais amplos desse acontecimento histórico e social, de proporções internacionais, que atingiu, e continua afetando diretamente, cerca de 600 mil pessoas. Abordo três procedimentos formais empregados no filme: (1) a utilização de fotografias domésticas; (2) a elaboração da narração em voz over; (3) o emprego de filmagens históricas realizadas por Hikoma Udihara, colonizador e cinegrafista pioneiro da imigração japonesa no Brasil. Através do mapeamento de possibilidades formais relacionadas aos procedimentos em questão, busco identificar e analisar um conjunto de conceitos, de instrumentos críticos e teóricos, úteis para se pensar a articulação entre o íntimo e o histórico, o pessoal e o social, em documentários na primeira pessoa; em diálogo constante com aspectos concretos da realização cinematográfica. / This master\'s thesis investigates formal possibilities of articulation between personal universes and historical processes inside the first person filmmaking practice. The bases are materials and procedures related to a feature documentary film that I am now developing, called Welcome Back, Farewell (Bem vindos de novo). The film addresses my family experiences in immigration of Japanese-Brazilians to Japan, known as \"dekassegui phenomenon\". In the film, I try to articulate personal and familiar experiences with wider features of this historical and social event of international proportion, which reached, and still concerns directly to six hundreds thousand people. Three formal procedures of the film are covered: (1) the use of domestic photography; (2) the elaboration of the voice over narration; (3) the usage of historical footage produced by Hikoma Udihara, colonizer and pioneer amateur filmmaker of the Japanese immigration in Brazil. Through the organization of formal possibilities related with the previous procedures, the aim is to identify and analyze a group of concepts, of critical and theoretical devices, useful to think the articulation between the intimate and the historical, the personal and the social, within the first person documentary; in frequent contact with concrete features of the filmmaking practice.
273

Clima e mortalidade: uma abordagem observacional ecológica na cidade de São Paulo / Climate and mortality: ecological observational approach in Sao Paulo

Samya de Lara Lins de Araujo Pinheiro 27 January 2014 (has links)
INTRODUÇÃO: Em um cenário de mudanças climáticas, o delineamento da associação e dos mecanismos de efeito entre fatores de risco ambientais, como temperatura e poluição, e saúde tornou-se foco de diversos estudos epidemiológicos. À medida que a exposição à poluição e às condições meteorológicas ocorre de forma simultânea, além do efeito isolado, devemos buscar compreender a interação entre tais fatores, observando se atuam como modificadores de efeito. O presente estudo caracterizou o efeito da temperatura e da poluição do ar, isolado e sinérgico, na mortalidade, a partir de dados secundários. MÉ- TODOS: Três tipos de metodologias foram aplicadas para avaliar a associação isolada da temperatura média e da concentração média diária de poluentes (MP10, NO2, O3) na mortalidade de indivíduos acima dos 40 anos por doenças cardiovasculares e na mortalidade de indivíduos acima dos 60 anos por doenças respiratórias, na cidade de São Paulo - Brasil entre 1998 e 2008. As estimativas de risco relativo produzidas em análises case-crossover com pareamento temporal bidirecional e com pareamento pelo fator confundidor, i.e. temperatura média ou poluente, foram comparadas aos resultados de uma análise tradicional de séries temporais. Para avaliar o efeito sinérgico entre os fatores de risco, interpretamos representações gráficas de superfícies geradas em modelos bivariados. RESULTADOS: Não foram observadas diferenças entre os resultados das análises case-crossover e da análise de séries temporais. Para mortalidade cardiovascular, estimou-se uma mudança percentual no risco relativo devido a um aumento de 10 ug/m3 na concentração do MP10 e do NO2, respectivamente, de 0,85% (0,45-1,25) e 0,26% (0,04-0,48). O aumento percentual no risco de mortalidade respiratória foi de 1,60% (0,74-2,46) e 1,29% (0,46-2,12), respectivamente para MP10 e O3. O efeito da temperatura foi analisado através das funções ajustadas para parametrizar sua relação com a mortalidade. O padrão observado para mortalidade cardiovascular foi de U-shaped. Para mortalidade respiratória foi de J-espelhado, identificando maior risco relativo em temperaturas altas. As análises case-crossover confirmaram que a associação positiva parametrizada para os poluentes não sofre confusão da temperatura, bem como a curva parametrizada para a temperatura não sofre confusão dos níveis de poluentes na análise de séries temporais. As figuras 3D produzidas pelo modelo bivariado ilustraram a dinâmica interativa entre os fatores de risco. O efeito na mortalidade cardiovascular é positivo em baixas concentrações de NO2 e de O3 combinadas com baixas temperaturas. A dimensão deste efeito é comparável ao efeito de altas concentrações em altas temperaturas. Para mortalidade respiratória, a combinação dos fatores mostra um padrão intuitivo de simples somatória dos efeitos. CONCLUSÕES: Métodos analíticos, como o método case-crossover, com controles mais intrínsecos do que parametrizações para variáveis confundidoras, produziram estimativas de risco relativo na mortalidade semelhantes às geradas na análise tradicional de séries temporais. A simultaneidade de exposição a diferentes níveis de fatores ambientais, como temperatura e poluição, pode gerar condições de efeito combinado tão preocupantes quanto as previstas para extremas concentrações / INTRODUCTION : In a climate change scenario, the description of the association and of the pathophysiological mechanisms linking environmental risk factors, such as temperature and air pollution, and health has been the focus in several epidemiological studies. Exposure to air pollution and weather conditions occurs simultaneously, therefore, in addition to the isolated effect, factors interactions and modification effects are key issue. The present study characterized the effect of temperature and air pollution, both isolated and synergistic effects, on mortality, from secondary data. METHODS: Three methods were applied to evaluate the association of average temperature and average daily concentration of pollutants (PM10, NO2, O3) on mortality caused by cardiovascular diseases among individuals over 40 years old and on mortality caused by respiratory diseases among individuals over 60 years old, in the city of Sao Paulo - Brazil, from 1998 to 2008 . We compared the estimates of relative risk produced in several case-crossover approaches, time-stratified bidirectional and matched by the confounding factor, i.e. average temperature or pollutant, to the results of a traditional time-series analysis. The risk factors synergistic effect was evaluated by the graphical interpretation of response surfaces generated by bivariate models. RESULTS: No statistical differences were observed between the results from the case-crossover and time-series analyses . The relative risk percent changes for cardiovascular mortality associated with an increase of 10 ug/m3 in the 24-h average concentrations of PM10 and NO2 are, respectively, 0.85% (0.45-1.25) and 0.26% (0.04-0.48). The percentage increase in the risk of respiratory mortality was 1.60% (0.74- 2.46) and 1.29% (0.46-2.12), respectively, for PM10 and O3. The effect of temperature was analyzed by smooth functions plots. The pattern observed for cardiovascular mortality was U-shaped. For respiratory mortality, the smooth function was J-shaped horizontal flipped, identifying higher relative risk at hot temperatures. The case-crossover analyzes confirmed that the positive association parameterized for pollutants is unlikely to be caused by confounding by temperature, as well as the parametric curve for temperature is unlikely to be caused by confounding by pollutant levels in time-series analysis. The bivariate model surface plots illustrated the dynamic interaction within the risk factors. The effect on cardiovascular mortality is positive at low concentrations of NO2 and O3 in combination with cold temperatures. The magnitude of this effect is comparable to the effect of high concentrations at hot temperatures. For respiratory mortality, the combination of risk factors is simple summation of effects, with no effect modifications of the original patterns. CONCLUSIONS: Analytical methods such as case-crossover method, controlled for confounding variables by design, produced estimates of relative risk in mortality similar to those generated in the traditional time-series analysis. The simultaneous exposure to several levels of environmental factors, such as temperature and air pollution, may represent conditions as harmful as the predicted to extreme concentrations, due to the combined effect
274

Clima e mortalidade: uma abordagem observacional ecológica na cidade de São Paulo / Climate and mortality: ecological observational approach in Sao Paulo

Pinheiro, Samya de Lara Lins de Araujo 27 January 2014 (has links)
INTRODUÇÃO: Em um cenário de mudanças climáticas, o delineamento da associação e dos mecanismos de efeito entre fatores de risco ambientais, como temperatura e poluição, e saúde tornou-se foco de diversos estudos epidemiológicos. À medida que a exposição à poluição e às condições meteorológicas ocorre de forma simultânea, além do efeito isolado, devemos buscar compreender a interação entre tais fatores, observando se atuam como modificadores de efeito. O presente estudo caracterizou o efeito da temperatura e da poluição do ar, isolado e sinérgico, na mortalidade, a partir de dados secundários. MÉ- TODOS: Três tipos de metodologias foram aplicadas para avaliar a associação isolada da temperatura média e da concentração média diária de poluentes (MP10, NO2, O3) na mortalidade de indivíduos acima dos 40 anos por doenças cardiovasculares e na mortalidade de indivíduos acima dos 60 anos por doenças respiratórias, na cidade de São Paulo - Brasil entre 1998 e 2008. As estimativas de risco relativo produzidas em análises case-crossover com pareamento temporal bidirecional e com pareamento pelo fator confundidor, i.e. temperatura média ou poluente, foram comparadas aos resultados de uma análise tradicional de séries temporais. Para avaliar o efeito sinérgico entre os fatores de risco, interpretamos representações gráficas de superfícies geradas em modelos bivariados. RESULTADOS: Não foram observadas diferenças entre os resultados das análises case-crossover e da análise de séries temporais. Para mortalidade cardiovascular, estimou-se uma mudança percentual no risco relativo devido a um aumento de 10 ug/m3 na concentração do MP10 e do NO2, respectivamente, de 0,85% (0,45-1,25) e 0,26% (0,04-0,48). O aumento percentual no risco de mortalidade respiratória foi de 1,60% (0,74-2,46) e 1,29% (0,46-2,12), respectivamente para MP10 e O3. O efeito da temperatura foi analisado através das funções ajustadas para parametrizar sua relação com a mortalidade. O padrão observado para mortalidade cardiovascular foi de U-shaped. Para mortalidade respiratória foi de J-espelhado, identificando maior risco relativo em temperaturas altas. As análises case-crossover confirmaram que a associação positiva parametrizada para os poluentes não sofre confusão da temperatura, bem como a curva parametrizada para a temperatura não sofre confusão dos níveis de poluentes na análise de séries temporais. As figuras 3D produzidas pelo modelo bivariado ilustraram a dinâmica interativa entre os fatores de risco. O efeito na mortalidade cardiovascular é positivo em baixas concentrações de NO2 e de O3 combinadas com baixas temperaturas. A dimensão deste efeito é comparável ao efeito de altas concentrações em altas temperaturas. Para mortalidade respiratória, a combinação dos fatores mostra um padrão intuitivo de simples somatória dos efeitos. CONCLUSÕES: Métodos analíticos, como o método case-crossover, com controles mais intrínsecos do que parametrizações para variáveis confundidoras, produziram estimativas de risco relativo na mortalidade semelhantes às geradas na análise tradicional de séries temporais. A simultaneidade de exposição a diferentes níveis de fatores ambientais, como temperatura e poluição, pode gerar condições de efeito combinado tão preocupantes quanto as previstas para extremas concentrações / INTRODUCTION : In a climate change scenario, the description of the association and of the pathophysiological mechanisms linking environmental risk factors, such as temperature and air pollution, and health has been the focus in several epidemiological studies. Exposure to air pollution and weather conditions occurs simultaneously, therefore, in addition to the isolated effect, factors interactions and modification effects are key issue. The present study characterized the effect of temperature and air pollution, both isolated and synergistic effects, on mortality, from secondary data. METHODS: Three methods were applied to evaluate the association of average temperature and average daily concentration of pollutants (PM10, NO2, O3) on mortality caused by cardiovascular diseases among individuals over 40 years old and on mortality caused by respiratory diseases among individuals over 60 years old, in the city of Sao Paulo - Brazil, from 1998 to 2008 . We compared the estimates of relative risk produced in several case-crossover approaches, time-stratified bidirectional and matched by the confounding factor, i.e. average temperature or pollutant, to the results of a traditional time-series analysis. The risk factors synergistic effect was evaluated by the graphical interpretation of response surfaces generated by bivariate models. RESULTS: No statistical differences were observed between the results from the case-crossover and time-series analyses . The relative risk percent changes for cardiovascular mortality associated with an increase of 10 ug/m3 in the 24-h average concentrations of PM10 and NO2 are, respectively, 0.85% (0.45-1.25) and 0.26% (0.04-0.48). The percentage increase in the risk of respiratory mortality was 1.60% (0.74- 2.46) and 1.29% (0.46-2.12), respectively, for PM10 and O3. The effect of temperature was analyzed by smooth functions plots. The pattern observed for cardiovascular mortality was U-shaped. For respiratory mortality, the smooth function was J-shaped horizontal flipped, identifying higher relative risk at hot temperatures. The case-crossover analyzes confirmed that the positive association parameterized for pollutants is unlikely to be caused by confounding by temperature, as well as the parametric curve for temperature is unlikely to be caused by confounding by pollutant levels in time-series analysis. The bivariate model surface plots illustrated the dynamic interaction within the risk factors. The effect on cardiovascular mortality is positive at low concentrations of NO2 and O3 in combination with cold temperatures. The magnitude of this effect is comparable to the effect of high concentrations at hot temperatures. For respiratory mortality, the combination of risk factors is simple summation of effects, with no effect modifications of the original patterns. CONCLUSIONS: Analytical methods such as case-crossover method, controlled for confounding variables by design, produced estimates of relative risk in mortality similar to those generated in the traditional time-series analysis. The simultaneous exposure to several levels of environmental factors, such as temperature and air pollution, may represent conditions as harmful as the predicted to extreme concentrations, due to the combined effect
275

Stimulation et contrôle de la recombinaison homologue chez le maïs pour augmenter l'efficacité du ciblage de gène et le brassage génétique

Ayar, Ayhan 19 March 2013 (has links)
La recombinaison homologue est un mécanisme de réparation de l’ADN extrêmement contrôlé et particulièrement chez les eucaryotes supérieurs. Dans les cellules méiotiques de ces derniers, où les cassures doubles brin de l’ADN sont programmées, les voies de crossing-over de la recombinaison homologue, qui génèrent de nouvelles combinaisons de gènes, sont restreintes. Dans les cellules somatiques, la recombinaison illégitime, qui assure majoritairement la réparation des cassures double brin de l’ADN, limite l’intégration ciblée du transgène par recombinaison homologue. Les entreprises de biotechnologie convoitent de maitriser la recombinaison homologue afin de contrôler d’une part le brassage génomique qui a lieu pendant la méiose, et d’autre part l’intégration du transgène dans le génome. Cette étude a porté sur le développement d’outils afin d’atteindre ces deux objectifs. Afin d’augmenter le brassage du génome, ayant lieu pendant la méiose, une version du promoteur OsDmc1b, active dans les cellules méiotiques, a été caractérisée chez le maïs. Des plantes sur-exprimant le gène ZmSpo11.1, sous contrôle de ce promoteur, ont ainsi été développées afin d’obtenir des lignées potentiellement hyper-recombinantes. Si la surexpression de ZmSpo11.1 permet effectivement d’augmenter le taux de crossing-over, il pourra être utilisé par les sélectionneurs afin d’accélérer l’introgression d’allèles d’intérêt dans des variétés élites. Concernant la mise en place d’une technique de ciblage de gène, deux stratégies, reposant sur l’utilisation de la méganucléase I-SceI, ont été testées. La démarche a nécessité trois éléments : un locus cible contenant le site de coupure I-SceI, une matrice de réparation et la séquence codant I-SceI (ou I-SceI::GR). La première stratégie, consistant à retransformer les lignées présentant le locus cible avec la matrice de réparation et I-SceI, ne semble pas exploitable car aucun évènement de ciblage de gène n’a été mis en évidence. La seconde stratégie, reposant sur l’assemblage des trois éléments par croisement, est beaucoup plus prometteuse. Malgré la faible activité d’I-SceI::GR, des évènements de recombinaison homologue ont été observés dans les tissus foliaires de certaines plantes. Du cal embryogène, développé à partir de ces dernières, a permis de régénérer des plantes présentant des évènements de ciblage de gène. Ces travaux ouvrent de nouvelles perspectives dans l’élaboration contrôlée d’OGM. / Homologous recombination is a DNA repair mechanism highly regulated in higher eukaryotes. In their meiotic cells, where DNA double-stranded breaks are programmed, the crossing-over pathway of homologous recombination, which generates new gene combinations, is limited in activity and genomic distribution. In somatic cells, illegitimate recombination, which mainly ensures DNA double-strand repair, limits the targeted integration of transgenes by homologous recombination. Biotechnology companies aim to master homologous recombination to control on the one hand the genomic mixing that occurs during meiosis, and on other hand, the integration of transgenes into the genome. This study focuses on the development of tools to achieve these two objectives.To increase genome mixing occurring during meiosis, a version of the OsDmc1b promoter active in maize meiotic cells was isolated. Then, plants over-expressing the ZmSpo11.1 gene under control of this promoter have been developed to obtain potentially hyper-recombinant lines. If ZmSPO11.1 overexpression increases the crossing over rate, it can be used by breeders to accelerate the introgression of alleles of interest into elite varieties. For the establishment of a gene targeting technique, two strategies based on the use of the I-SceI meganuclease were tested. These approaches involved the use of three elements which are: a target locus containing the cleavage site of I-SceI, a repair template and the sequence encoding I-SceI (or ISceI::GR). The first strategy, consisting of the retransformation of target locus lines with the repair template and I-SceI, does not seem workable because no gene targeting events were isolated. The second strategy, based on the assembly of the three components by crossing, is more promising. Despite the low activity of I-SceI::GR, homologous recombination events were observed in leaf tissues of certain plants. Embryogenic callus, developed from these plants, permitted the regeneration of plants with gene targeting events. This work opens new perspectives in the development of controlled GMO production.
276

交叉實驗設計之探討及分析 / A Study on Cross-over Design

呂怡瑱, Lu, Yi Jenn Unknown Date (has links)
在本文中,分別就四種不同參數組合(包括六個模式)的二維交叉實驗設計,採用一般線性模式法及二樣本t檢定法予以分析,並探討模式間與分析方法間的異同。此外,在二維重覆測量交叉實驗設計方面,我們也分別以單變量分裂區集變異數分析法及多變量變異數分析法進行探討。 / Four possible parametrizations ( including six models ) are considered in this study to clearify some ambigous issues related to a 2*2 cross-over design. Each model is analyzed using both the GLM procedure and two-sample t test. In addition, we also discuss issues related to the 2*2 repeated measurements cross-over design by using the univariate split-plot and multivariate analysis of variance techniques.
277

La voix-over dans le cinéma documentaire

Campeau-Vallée, Guillaume 08 1900 (has links)
Ce travail est un défrichement qui cherche à explorer les usages de la voix-over dans le cinéma documentaire. Questionnant sa nature éminemment hétérogène, cette étude de la voix dans le registre over portera d'abord sur sa matérialité dans le champ du sonore, avant de s'attarder à ses fonctions dans l'élaboration du discours documentaire. Comme il s'agit d'une entreprise nouvelle, il y aura de nombreux aller-retours entre les très rares études menées sur la voix-over–presque exclusivement circonscrites au cinéma de fiction (Kozloff, Châteauvert, Boillat)–et différents travaux théoriques et critiques traitant des enjeux de la représentation du réel dans le cinéma documentaire (Nichols, Niney, Gauthier). Cela permettra de mettre en lumière le cas du cinéma documentaire où la voix-over occupe des fonctions beaucoup moins narratives que discursives. Il sera vu comment cette parole (comme occurrence sonore et comme productrice de sens) est posée par-dessus (over) les images, entretenant avec elles des rapports d'interdépendance parfois convergents, mais parfois divergents. On comprendra aussi que dans son usage spécifiquement documentaire, la voix-over contribue à rendre plus manifeste la prise de parole d'un sujet sensible et pensant qui offre ni plus ni moins une interprétation du monde. Aussi, ce mémoire est un diptyque. Le présent texte doit donc être considéré en correspondance avec le film documentaire D'où, chose étonnante, rien ne s'en suit, qui constitue le deuxième volet de l'ouvrage. Mots clés : cinéma, documentaire, voix-over, parole, son. / This exploratory thesis examines the various practices of voice-over in documentary film. Questioning the highly heterogeneous nature of voice in the over register, I first discuss it with respect to the material aspects of sound before examining it’s functions in the elaboration of documentary discourse. Because this is a new undertaking, I will travel back- and-forth between the rare studies concerning voice-over–almost exclusively confined to fiction film (Kozloff, Châteauvert, Boillat)–and works proposing different theoretical and critical views on the representation of reality in documentary films (Nichols, Niney, Gauthier). This will help bring to light the specificities of documentay cinema where voice- over is used less towards the production of a narrative and more towards the articulation of discourse. With the help of examples from a range of documentary films, I will show how speech (both as an occurrence of sound and as a means of producing meaning) is placed over the images, in a sometimes converging, but sometimes diverging, interdependent relationship. This will help demonstrate that the specific use of voice-over in documentary film makes manifest the act of speech of the sensitive, thinking subject who offers, no more no less, than an interpretation of the world. Also, this thesis is a diptych and needs to be considered in correspondence with the documentary film D'où, chose étonnante, rien ne s'en suit that constitutes second part of the work. Keywords : cinema, documentary, voice-over, speech, sound. / Il s'agit d'une maîtrise-création donc le texte s'accompagne du film en fichier complémentaire.
278

Investigation on radio channel over the air emulation by multi-probe setup / L'émulation d'un canal de propagation en rayonnée à l'aide d'un setup multi-sonde

Belhabib, Mounia 09 November 2017 (has links)
La nécessité d'une transmission sans fils des données à des débits élevés, à la fois fiables et avec de faible latence a donné lieu à ces dernières années à une succession de normes sans fil, allant de 3G-4G, WLAN à la cinquième génération (5G) des réseaux mobiles. Dans ce contexte, les équipementiers, ainsi que les opérateurs, doivent élaborer des méthodes d'essai standard précises et efficaces pour évaluer les performances des systèmes et des terminaux. Les méthodologies de test en direct par voie aérienne ("Over-The-Air") (OTA) visent à reproduire des environnements multi-trajets radio en laboratoire de manière répétable et contrôlable, en évitant les coûteuses mesures in-situ. L'objectif de cette thèse est de proposer une nouvelle méthodologie d'essai OTA, afin de reproduire la propagation des canaux radio, sur une large bande et d'évaluer les performances des systèmes sans fil dans des environnements réels. La thèse débute en présentant les bases de la chaîne radio et de certains modèles de chaînes présentés dans la littérature. Ensuite, un examen critique des méthodologies OTA existantes dans la littérature est fourni. Parmi les différentes méthodologies, nous avons opté pour l'approche de la chambre anéchoïde multi-sonde, qui consiste à déployer un certain nombre de sondes autour d'un équipement radio sous test et à les alimenter avec un émulateur d’évanouissements (fading). Cette méthodologie fournit une reproduction précise des caractéristiques des canaux spatiaux, qui sont nécessaires pour évaluer la performance des terminaux multi-antennes dans des environnements réels. L'avantage le plus important de cette méthodologie est la capacité d'imiter différents modèles de canaux en termes de résolution spatiale, d’évanouissements angulaire et temporel. Un outil de simulation a été développé pour étudier et déterminer les caractéristiques de l'installation OTA pour différents types de canaux d’intérêt. En particulier, le nombre et la mise en place des antennes nécessaires et la taille de l'installation ont été étudiés en fonction de la taille électrique du dispositif testé. Sur la base des études de dimensionnement, une configuration OTA expérimentale a été réalisée pour reproduire les caractéristiques des canaux dans l'espace tridimensionnel pour une plage de fréquences de 2 à 6 GHz. / The need for high data-rate, reliable and low latency transmission in wireless communication systems motivated a multitude of wireless standards, spanning from 3G-4G, WLAN to the upcoming fifth generation (5G) of mobile networks. In this context, technology providers, as well as operators, need to develop accurate and cost effective standard test methods, to evaluate devices performance. Over-The-Air (OTA) test methodologies aim to reproduce radio multipath environments in laboratory in repeatable and controllable manner, avoiding costly field test. The focus of this thesis is to propose a new OTA test methodology, in order to emulate radio channel propagation, over a wide band, and to evaluate the performance of the wireless systems in real environments. We start our study by introducing the basics of radio channel and some channel models presented in literature. Then a critical review of existing OTA methodologies in literature is provided. Among the different methodologies we opted for the multi-probe anechoic chamber approach, which consists into deploying a number of probes around a device, and feed them with fading emulator. This methodology provides an accurate reproduction of spatial channel characteristics, which are needed to assess the performance of multi-antenna terminals in real environments. The most important advantage of this methodology is the capability to emulate different channel model in term of spatial resolution, angular and temporal fading. A simulation tool was developed to investigate and determine the OTA setup under different channel condition. In particular the number and emplacement of antennas needed and the size of the setup were investigated as a function of the electrical size of the device under test. Based on the dimensioning studies, an experimental OTA setup was realized to reproduce the channel characteristics in the three dimensional space for a frequency range from 2 to 6 GHz.
279

Ensaio em família: Bem vindos de novo São Paulo / -

Marcos Vinicius Yoshisaki 27 September 2018 (has links)
A dissertação investiga possibilidades formais de articulação entre universos pessoais e processos históricos no campo da realização documentária em primeira pessoa. O ponto de partida são materiais e procedimentos advindos de um documentário de longa-metragem que atualmente desenvolvo, intitulado Bem vindos de novo. O filme aborda as experiências da minha família na imigração de nipo-brasileiros para o Japão, conhecida como \"fenômeno decasségui\". Nele, busco articular as experiências pessoais e familiares com aspectos mais amplos desse acontecimento histórico e social, de proporções internacionais, que atingiu, e continua afetando diretamente, cerca de 600 mil pessoas. Abordo três procedimentos formais empregados no filme: (1) a utilização de fotografias domésticas; (2) a elaboração da narração em voz over; (3) o emprego de filmagens históricas realizadas por Hikoma Udihara, colonizador e cinegrafista pioneiro da imigração japonesa no Brasil. Através do mapeamento de possibilidades formais relacionadas aos procedimentos em questão, busco identificar e analisar um conjunto de conceitos, de instrumentos críticos e teóricos, úteis para se pensar a articulação entre o íntimo e o histórico, o pessoal e o social, em documentários na primeira pessoa; em diálogo constante com aspectos concretos da realização cinematográfica. / This master\'s thesis investigates formal possibilities of articulation between personal universes and historical processes inside the first person filmmaking practice. The bases are materials and procedures related to a feature documentary film that I am now developing, called Welcome Back, Farewell (Bem vindos de novo). The film addresses my family experiences in immigration of Japanese-Brazilians to Japan, known as \"dekassegui phenomenon\". In the film, I try to articulate personal and familiar experiences with wider features of this historical and social event of international proportion, which reached, and still concerns directly to six hundreds thousand people. Three formal procedures of the film are covered: (1) the use of domestic photography; (2) the elaboration of the voice over narration; (3) the usage of historical footage produced by Hikoma Udihara, colonizer and pioneer amateur filmmaker of the Japanese immigration in Brazil. Through the organization of formal possibilities related with the previous procedures, the aim is to identify and analyze a group of concepts, of critical and theoretical devices, useful to think the articulation between the intimate and the historical, the personal and the social, within the first person documentary; in frequent contact with concrete features of the filmmaking practice.
280

An Algorithmic Characterization Of Polynomial Functions Over Zpn

Guha, Ashwin 02 1900 (has links) (PDF)
The problem of polynomial representability of functions is central to many branches of mathematics. If the underlying set is a finite field, every function can be represented as a polynomial. In this thesis we consider polynomial representability over a special class of finite rings, namely, Zpn, where p is a prime and n is a positive integer. This problem has been studied in literature and the two notable results were given by Carlitz(1965) and Kempner(1921).While the Kempner’s method enumerates the set of distinct polynomial functions, Carlitz provides a necessary and sufficient condition for a function to be polynomial using Taylor series. Further, these results are existential in nature. The aim of this thesis is to provide an algorithmic characterization, given a prime p and a positive integer n, to determine whether a given function over Zpn is polynomially representable or not. Note that one can give an exhaustive search algorithm using the previous results. Our characterization involves describing the set of polynomial functions over Zpn with a ‘suitable’ generating set. We make use of this result to give an non-exhaustive algorithm to determine whether a given function over Zpn is polynomial representable.nβ

Page generated in 0.0336 seconds