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1
Jayachandran, Krishna K. "STBC-encoded cooperative asynchronous transmissions for transmission energy efficiency." Diss., Online access via UMI:, 2005.
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2
Amai, Nikabou. "Contribution à la modélisation paramétrique en transmission mécanique : le modèle ARMAX entre l'erreur de transmission et le bruit d'engrènement." Lyon, INSA, 1998. http://www.theses.fr/1998ISAL0118.
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La conception des transmissions par engrenages s'oriente maintenant vers une réduction des nuisances sonores et vibratoires, après avoir optimisé les géométries. Depuis quelques années, l'erreur de transmission est considérée comme la principale excitation mesurable des systèmes engrenants. Dans le cadre de ce travail, nous avons cherché à établir un modèle expérimental du transfert entre l'erreur de transmission et le bruit d'engrènement d'un étage de réduction, prenant en compte les conditions de fonctionnement. Parmi les structures de modèles paramétriques disponibles, seul le modèle ARMAX permet d'avoir une bonne représentation de la fonction de transfert avec un faible nombre de paramètres. Ce modèle nécessite néanmoins une mise en forme des signaux et une étude par bandes de fréquence. L'étude présentée porte essentiellement sur la fréquence d'engrènement. L'interprétation physique du modèle passe par l'établissement de l'équation différentielle gouvernant le système modélisé. Cette première approche a montré que l'excitation du système est caractérisée par une combinaison linéaire de l'erreur de transmission et de sa dérivée par rapport au temps. Une étude paramétrique par la méthode des plans d'expériences a montré que la charge appliquée sur la denture n'intervient pas et que les facteurs géométriques de conception sont couplés aux facteurs de fonctionnement. Ces facteurs modifient le système de génération du bruit d'engrènement. La prise en compte de ces modifications sur les coefficients de l'équation différentielle permet de proposer un modèle hybride complet du transfert entre l'erreur de transmission et le bruit d'engrènement. Cette démarche est transposable à des transmissions de puissance complètes de type "boîte de vitesses"Design of gear power transmissions moves towards reduction of vibration and noise pollution after have improving geometry. Since several years, transmission error is recognised as the main measurable excitation of the gearing mechanisms. In this work, we have chosen to introduce an experimental model of transfer between transmission error and acoustic effects on a one-stage gearing system, taking into account real operating conditions. From the available structures of parametric model, only the ARMAX model seems to be a reliable description of transfer function with a low number of parameters. These models nevertheless require signal modifications and an analysis by frequency bands. The presented study is essentially concerned with mesh frequency. The physical interpretation of the models runs though establishment of the differential equation which governs the concerned system. This first approach shows that the excitation is described by a combination of transmission error and its first time derivative. A parametric study, with the help of experimental design, leads to the conclusion that load is not the most influent factor and that geometric factors are associated with operating factors. These factors change the mechanism of gear noise generation. Taking these modifications into account on differential equation coefficients permits to propose a complex hybrid model of the transfer between transmission error and gearing noise. This modelisation method can be used on entire gearing power transmissions like automotive gearbox
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Ulsund, Ragnar. "Offshore Power Transmission : Submarine high voltage transmission alternatives." Thesis, Norwegian University of Science and Technology, Department of Electrical Power Engineering, 2009. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-9937.
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Offshore power transmission is becoming an increasingly important issue. To moderate climate change, world leaders have set environmental goals that will be very difficult to reach without renewable power production and the removal of production units with high emissions. Wind power and electrification have been the focus in this report. Plans for the expensive wind power are already moving offshore. This report has made an attempt at suggesting a guideline for well-suited transmission systems, for wind power projects located at a distance in order to make them more economically attractive. Another emphasis has been to find the most suitable transmission system for gas turbines at offshore installations. As expected, the use of alternating current is best suited at shorter distances. At longer distances this system is still feasible up to 350 km, but losses will be high and there will be limited power available. A conventional thyristor-based direct current system will therefore be an attractive option for high power ratings and long distances. On the other hand, direct current based on voltage-source converters is considered more expensive, but has an improved control of reactive power and is therefore preferable to the conventional direct current system. To determine which system has the best design, one has to consider each case individually.
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Rodriguez, Claudia Patricia. "Transmission pricing." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0028/MQ50390.pdf.
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Shang, Wenzhuo. "Essays on electricity transmission investment and financial transmission rights." [Ames, Iowa : Iowa State University], 2006.
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Freschi, Carla Roberta [UNESP]. "Investigação experimental sobre a transmissão aerógena e naso-nasal de Salmonella enterica subespécie enterica sorotipo Derby em suínos." Universidade Estadual Paulista (UNESP), 2007. http://hdl.handle.net/11449/101255.
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Os suínos e seus produtos são considerados importantes fontes de salmonelose humana. Desta forma, o controle das infecções nas granjas é considerado essencial para a prevenção de Salmonella na cadeia produtiva de suínos. No entanto, o maior entrave na profilaxia da infecção é, principalmente, a falta de conhecimentos sobre sua epidemiologia em sistemas de produção intensivos de criação de suínos, principalmente em relação às possíveis vias de transmissão desse agente. Este estudo testou a hipótese da transmissão nasonasal (E1) e aerógena (E2) de Salmonella Derby na espécie suína. Os experimentos foram realizados em isoladores construídos em aço inoxidável e vidro e totalmente controlados. No E1, os isoladores dos suínos inoculados e dos suínos sentinela estavam conectados por pequena fenda que permitia apenas o contato naso-nasal. Em E2 os isoladores estavam conectados por condutores de ar que permitiam o fluxo de ar unidirecional do isolador 1 (suínos controle) ao isolador 3 (suínos sentinela), passando pelo isolador 2 (suínos inoculados). A duração de ambos experimentos foi de 15 dias. Nesse período, amostras dos sacos de dejetos, dos suabes retais, das fezes do piso e do ar foram colhidas diariamente e avaliadas quanto a presença de Salmonella. A hipótese de transmissão naso-nasal e aerógena de S. Derby não foi corroborada pelo isolamento e detecção do agente nos animais sentinela.
Pork and pork products are recognized as one of the major sources for human salmonellosis. Howeveri the infection control in the farms is considered essential for the Salmonella prevention in the productive swine chain. However, the most impediment in the infection prophylaxis is, mainly, the lack of knowledge on its epidemiology in intensives production systems, mainly related to the transmission possible ways of this agent. This study has tested the hypothesis of nose-to-nose and airborne transmission of Salmonella Derby in the swine species. The trials were performed using stainlesssteel and glass isolation cabinets and totally controlled. In the trial 1, inoculated pigs and sentinel pigs isolation cabinets were connected by small crack that allowed only the nose-to-nose contact. In the trial 2 isolation cabinets were connected by air ducts that allowed an unidirectional airflow from cabinet 1 (control pigs) to cabinet 3 (sentinel pigs), passing through cabinet 2 (inoculated pigs). The duration of both trials were 15 days. At this period, slurry bags, rectal swabs, pooled faecal from the floor and air samples were collected daily and assessed by culture and PCR. The nose-to-nose and airborne transmission hypothesis of S. Derby was not corroborated by the agent isolation and detection in the sentinel pigs.
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Kwon, Youngho. "Estimating the value of financial transmission rights for transmission expansion." Thesis, University of Manchester, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.497600.
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The current situation of insufficient investment in transmission tends to weaken the advantages of a deregulated power industry. These shortages mainly arise because of the risk of not recovering the cost of investing in new lines Location Marginal prices (LMPs) and Financial Transmission Rights (FTRs) are key elements in reducing these investment risks. Market participants are able to hedge against price fluctuations caused by transmission congestion through the purchase or sale of FTRs. The value of FTRs, which is tied to the difference in prices between locations in the network, would indicate where transmission expansion should be implemented.
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Dán, György. "Internet Video Transmission." Doctoral thesis, KTH, School of Electrical Engineering (EES), 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-623.
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The Internet has rapidly evolved from being a scientific experiment to a commercial network connecting millions of hosts that carries traffic generated by a large amount of applications with diverse requirements. Its architecture was however designed to enable efficient point-to-point delivery of bulk data, and can not provide statistical guarantees on the timely delivery of delay sensitive data such as streaming and real-time multimedia. Thus, applications that require low loss probabilities in today's Internet have to use some end-to-end error recovery mechanism. For delay sensitive applications the introduced latency by the applied schemes has to be low as well. Traffic control functions such as delay limited shaping and forward error correction (FEC), and multiple description coding (MDC) have been proposed for variable bitrate video. Their major drawback is, however, that it is difficult to predict their efficiency, as it depends on many factors like the characteristics of the stream itself, the characteristics of the traffic in the network and the network parameters. Consequently, it is difficult to decide which control mechanisms to employ, how to combine them and to choose the right parameters (e.g. block length, code rate) for optimal performance.
In this thesis we present results on the efficiency of traffic control functions and MDC for video transmission based on mathematical models and simulations. We investigate the efficiency of delay limited traffic shaping and the trade-offs in the joint use of traffic shaping and forward error correction. We identify the packet size distribution of the traffic in the network as an additional factor that may influence the efficiency of FEC, and present a thorough analysis of its possible effects. We present an analytical comparison of MDC versus media-dependent FEC and media-independent FEC, and based on the results we conclude that MDC is a promising error control solution for multimedia communications with very strict delay bounds in an environment with bursty losses. We combine the analytical results with traces from measurements performed on the Internet to evaluate how efficient these error control schemes are under real loss patterns. We compare the efficiency of MDC and media-dependent FEC in the presence of channel estimation errors; we propose a new rate allocation method, which is robust to mis-estimations of the channel state and which improves error resilience on non-stationary channels. Finally we present an analytical model of the performance of an end-point-based multimedia streaming architecture based on multiple distribution trees and forward error correction, and analyze the behavior of the architecture for a large number of nodes.
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Dan, György. "Internet Video Transmission." Doctoral thesis, KTH, Telekommunikationssystem, TSLab, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-623.
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The Internet has rapidly evolved from being a scientific experiment to a commercial network connecting millions of hosts that carries traffic generated by a large amount of applications with diverse requirements. Its architecture was however designed to enable efficient point-to-point delivery of bulk data, and can not provide statistical guarantees on the timely delivery of delay sensitive data such as streaming and real-time multimedia. Thus, applications that require low loss probabilities in today's Internet have to use some end-to-end error recovery mechanism. For delay sensitive applications the introduced latency by the applied schemes has to be low as well. Traffic control functions such as delay limited shaping and forward error correction (FEC), and multiple description coding (MDC) have been proposed for variable bitrate video. Their major drawback is, however, that it is difficult to predict their efficiency, as it depends on many factors like the characteristics of the stream itself, the characteristics of the traffic in the network and the network parameters. Consequently, it is difficult to decide which control mechanisms to employ, how to combine them and to choose the right parameters (e.g. block length, code rate) for optimal performance. In this thesis we present results on the efficiency of traffic control functions and MDC for video transmission based on mathematical models and simulations. We investigate the efficiency of delay limited traffic shaping and the trade-offs in the joint use of traffic shaping and forward error correction. We identify the packet size distribution of the traffic in the network as an additional factor that may influence the efficiency of FEC, and present a thorough analysis of its possible effects. We present an analytical comparison of MDC versus media-dependent FEC and media-independent FEC, and based on the results we conclude that MDC is a promising error control solution for multimedia communications with very strict delay bounds in an environment with bursty losses. We combine the analytical results with traces from measurements performed on the Internet to evaluate how efficient these error control schemes are under real loss patterns. We compare the efficiency of MDC and media-dependent FEC in the presence of channel estimation errors; we propose a new rate allocation method, which is robust to mis-estimations of the channel state and which improves error resilience on non-stationary channels. Finally we present an analytical model of the performance of an end-point-based multimedia streaming architecture based on multiple distribution trees and forward error correction, and analyze the behavior of the architecture for a large number of nodes.QC 20101115
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Wang, Limin. "Progressive image transmission." Thesis, University of Ottawa (Canada), 1988. http://hdl.handle.net/10393/5394.
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Dán, György. "Internet video transmission /." Stockholm, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-623.
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Rossi, Jose Osvaldo. "Transmission line transformers." Thesis, University of Oxford, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.284500.
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Filos, Jason. "Parallel Transmission MRI." Thesis, Imperial College London, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.516789.
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KLAUSNER, JEREMIAS CORAL. "TRANSMISSION LINE MODEL." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 1992. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=8740@1.
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CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOEste trabalho apresenta uma metodologia para simulação de linhas de transmissão, geradores, interconexões e cargas por modelos baseados em filtragem digital. Estes modelos usam de maneira intensiva o conceito de redes digitais equivalentes, para resolver problemas aliados à responsabilidade dos filtros digitais em redes onde haja interconexão de elementos, desde simples cargas a subredes. O resultado deste trabalho é um sistema que representa de maneira quase que integral o espectro do sinal discretizado, em contraposição aos métodos tradicionalmente encontrados na simulação de sistemas deste tipo por computador digital. Por outro lado o processo é facilmente implementado por processadores digitais de sinal (DSPs), resultado em simulações em tempo rela comparáveis a simulações off-line por aplicativos
This thesis introduces a metodology for the simulation of transmission lines, power generators, interconnnections and loads, base don digital filtering models. These models make intensive use of digital equivalent network concepts in order to solve the computability problem of the digital filter. The result of this work is a system that represents the discrete-time signal on a bandwsiths covering up to the Nyquist frequency, in contraposition with traditional methods of computer simulation. The structure is easily implemented with Digital signal Processors (DSPs), resulting in real time simulations that compare to off-line circuit simulators in precision.
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Lisachenko, V. O. "Wireless energy transmission." Thesis, Sumy State University, 2016. http://essuir.sumdu.edu.ua/handle/123456789/45007.
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Technologies have never played such an important role as nowadays. We can`t imagine our world without them. Тhey are spread everywhere.
Wireless energy transmission is transmission by using different electromagnetic wave frequencies. Different frequencies are needed to reach different goals.
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Wlazlowski, Szymon S. "Asymmetric price transmission." Thesis, Aston University, 2008. http://publications.aston.ac.uk/10899/.
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Johnson, Allison Adah Johnson Allison Adah Johnson Allison Adah Johnson Allison Adah. "Transmission/translation/transgression /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2003. http://wwwlib.umi.com/cr/ucsd/fullcit?p3099912.
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Thesis (Ph. D.)--University of California, San Diego, 2003.Vita. "Three related compositions written for string quartet, small ensemble (soprano, violin, viola, cello, flute, clarinet, piano) and percussion duo"--P. viii; 3rd work an open form composition. Also available on the World Wide Web. (Access restricted to UC campuses).
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Kresock, Sylvia Anne. "Lost in Transmission." Thesis, The University of Arizona, 2011. http://hdl.handle.net/10150/144569.
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Vidigal, Rodrigo Fernandes. "Análise do comportamento de uma linha de um pouco mais de meio comprimento de onda sob diferentes condições de operação em regime permanente e durante a manobra de energização." [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/259602.
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Orientador: Maria Cristina Dias TavaresDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação
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Resumo: Este trabalho apresenta uma análise do comportamento de uma linha de transmissão isolada de um pouco mais de meio comprimento de onda (2600 km) na freqüência fundamental, 60 Hz, alimentada a partir de uma barra infinita para diferentes condições de operação. Os perfis de tensão e de corrente, para diferentes condições de carregamento, são monitorados ao longo da linha. Uma análise do fator de potência da potência injetada no terminal emissor também é realizada e sua influência nos perfis de tensão e de corrente é verificada. As perdas ao longo da linha para diferentes níveis de potência transmitida são medidas e uma alternativa para minimização dessas perdas é apresentada. Uma metodologia de análise sistemática na freqüência fundamental de um sistema elétrico de potência identificando as condições críticas é também apresentada. A presente metodologia é aplicada em um sistema formado por linhas de transmissão de 500 kV existentes no sistema elétrico brasileiro, as quais são interligadas formando um tronco de 2600 km com a finalidade de representar uma linha de transmissão de um pouco mais de meio comprimento de onda. As análises feitas nesse trabalho consistem na verificação do comportamento do sistema na presença de diferentes tipos de curtos-circuitos em diferentes pontos da linha. Após a análise sistemática em regime permanente, as condições extremas podem ser simuladas em um programa de transitórios eletromagnéticos. Deste modo o comportamento da linha isolada alimentada a partir de uma barra infinita na presença de diferentes tipos de curtos-circuitos é discutido e os principais resultados são apresentados nesse trabalho. O tronco de 2600 km formado por linhas de 500 kV existentes no Brasil foi utilizado para simular a manobra de energização. As simulações incluíram diferentes técnicas de energização como o fechamento direto das fases, a utilização de um resistor de pré-inserção e o chaveamento controlado. Para cada alternativa de chaveamento foram analisadas as sobretensões transitórias e o perfil de tensão ao longo da linha. As simulações foram feitas utilizando-se os softwares ATP e PSCAD/EMTDC
Abstract: This work presents an analysis of the behavior of an isolated transmission line with a little more than half-wave length (2600 km) on fundamental frequency, 60 Hz, connected to an infinite busbar for different operating conditions. The voltage and current profiles for different loading conditions are monitored along the line. An analysis of the influence of the power factor of the transmitted energy on the voltage and current profiles along the line is performed. The losses along the line for different levels of transmitted power are measured and a method to minimize these losses is presented. A systematic review methodology in the fundamental frequency of a power system identifying the critical conditions is also presented. This methodology is applied to a system formed by 500 kV existing transmission lines in the Brazilian electrical system, which are interconnected forming an AC-link of 2600 km in order to represent a transmission line of a little more than half-wave length. The analysis made in this paper means to verify the system behavior in the presence of different types of short circuits at different points along the line. After systematic analysis in steady state, the extreme conditions can be simulated in an electromagnetic transient program. Thus the behavior of the isolated line connected to an infinite busbar in the presence of different types of short circuits is discussed and the main results are presented in this paper. The 2600 km AC-link formed by actual Brazilian 500 kV lines was used to simulate the trunk energization. The simulations included different techniques such as direct closure energization, the use of a pre-insertion resistor and the controlled switching. For each alternative it was analyzed the transient overvoltage profile along the line. The simulations were done with the software ATP and PSCAD / EMTDC
Mestrado
Energia Eletrica
Mestre em Engenharia Elétrica
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Levin, Candyce. "HIV transmission to transmission to premature very low birth weight infants." Master's thesis, Faculty of Health Sciences, 2021. http://hdl.handle.net/11427/32779.
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There is sparse literature about HIV transmission in preterm infants. Eighty-two HIV-exposed preterm infants received birth polymerase chain reactions (PCRs). Five (6.1%) were HIV positive with all 5 mothers receiving inadequate antiretrovirals. Of the PCRnegative infants, 9 died and 87% of the survivors received further PCR testing which remained negative. With correct care, intrapartum transmission of HIV can virtually be eliminated.
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Moratoya, Elsie Estela. "Transmissão e volatilidade de preços das commodities agrícolas." Universidade Federal de Goiás, 2014. http://repositorio.bc.ufg.br/tede/handle/tede/3381.
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This study presents an empirical analysis of price and volatility transmission for soybean and corn prices, between an international market, represented by the Chicago Board of Trade, and four domestic markets in Brazil: State of Goiás, Mato Grosso, Paraná and Rio Grande do Sul. Daily soybean and corn prices were collected for the period January, 2008 to June 2013 from the Centre for Advanced Studies in Applied Economics and the Institute of Agricultural Economics in Brazil. Henceforth, returns for the nominal price series were calculated and logaritmized for a preliminary to assess the behavior of the series, in which all were found to be integrated of order (1). Furthermore, the international market and domestic markets were found to be highly correlated. Co-movement and price transmission speed for both crops in all domestic markets and international market were measured using the Johansen cointegration test and the error correction model. Empirical results for the soybean prices presented the state of Rio Grande do Sul as the market that more rapidly adjusts to international market prices, at a rate of speed of 55%. Soybean prices in the state of Goiás corrected at a rate of 40%, Mato Grosso at a rate of 46%, and Paraná at a rate of speed of 55%. In terms of corn prices, the state of Goiás was the first to arrive at equilibrium with those of CBOT, at a rate of speed of 1.12%. Corn prices in the state of Mato Grosso corrected at a rate of 0.67% and Paraná and Rio Grande do Sul at a rate of 0.83%. Volatility transmission was determined with the use of a lower triangular GARCH - BECK model and the Impulse Response Function. The results showed that, in the case of soybean prices, the state of Goiás was the only one that presents no evidence of volatility transmission. Evidence of volatility transmission was found from CBOT to Mato Grosso, Parana to CBOT and bi-directional transmission between CBOT and Parana. Furthermore, results of the impulse response function show that a shock in the international soybean prices on prices of the State of Goiás did not normalize within a period of twenty four months. Other domestic markets showed a tendency to stabilize on an average of twenty months. In the case of corn prices, evidence of bi-directional volatility transmission was found between CBOT prices and Goias, Mato Grosso and Parana. Volatility transmission was unidirectional for Rio Grande do Sul and CBOT. The reaction to a shock in prices in the international market showed that the persistence of the shock in the domestic markets lasted an average of ten days before normalizing. The results show that price and volatility transmission between the domestic markets for the commodities analyzed and CBOT do exist and new information within the individual markets play a bigger role on returns volatility than new information from CBOT.
Este estudo apresenta uma análise empírica de transmissão de preços e de volatilidade nos preços da soja e do milho entre o mercado internacional, representado pela CBOT, e quatro mercados domésticos no Brasil: o Estado de Goiás, Mato Grosso, Paraná e Rio Grande do Sul. Para isso, foram selecionados os preços diários da soja e do milho, para o período entre janeiro de 2008 e junho de 2013. Os preços foram obtidos junto ao Centro de Estudos Avançados de Economia Aplicada e o Instituto de Economia Agrícola; em seguida, foram convertidos em retornos e logaritimizados para as análises. Posteriormente, foi feita uma análise preliminar dos preços nominais para avaliar o comportamento das séries temporais, em que foi verificada a estacionariedade de ordem (1) para todas as séries de preços. Foi também constatada uma alta correlação entre o mercado internacional e os mercados domésticos. O comovimento e a velocidade da transmissão dos preços foram estimados mediante o uso do teste de cointegração de Johansen e o modelo de correção de erros. Os resultados apontaram uma cointegração entre os mercados domésticos e o mercado internacional para as duas culturas. Os resultados empíricos dos testes para os preços da soja mostraram que o Estado do Rio Grande do Sul é o mercado que mais rapidamente se ajusta e se equilíbra com os preços da CBOT, numa velocidade de 55%. Os preços da soja no Estado de Goiás se ajustam a uma velocidade de 40%, o de Mato Grosso a uma velocidade de 46%, e o Paraná a uma velocidade de 55%. Quanto aos preços do milho, o Estado de Goiás é o que mais rapidamente se equilibra com os preços da CBOT, com uma velocidade de 1,12%. Os preços do Mato Grosso se corrigem a uma velocidade do 0,67% e os mercados do Paraná e Rio Grande do Sul a uma velocidade de 0,83%. A análise empírica da transmissão de volatilidade foi estimada pelo uso do modelo GARCH-BECK triangular inferior. Os resultados para a soja apontam que o mercado do Estado de Goiás foi o único que não apresentou evidência de transmissão de volatilidade. Existência de transmissão de volatilidade foi encontrado da CBOT para Mato Grosso, do Paraná para CBOT, e bidirecional entre Rio Grande do Sul e CBOT. Além disso, os resultados da Função Resposta ao Impulso mostram que um choque do mercado internacional no mercado do Estado de Goiás não chega à estabilidade em um período de vinte e quatro meses. Os outros mercados domésticos mostraram uma tendência de se estabilizar, em média, a partir de vinte meses. No caso do milho, foram encontradas evidências de transmissão de volatilidade bidirecional nos Estados de Goiás, Mato Grosso e Paraná, e transmissão unidirecional de Rio Grande do Sul para CBOT. A reação a um choque da CBOT mostra que a persistência do choque nos mercados domésticos leva, em média, dez dias para se estabilizar. Portanto, os resultados mostram que existe transmissão de preços e de volatilidade entre os mercados domésticos para os commodities analisados com a CBOT, além do que as novas informações dos proprios mercados possuem maior papel na volatilidade dos retornos que das informações da CBOT.
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Sainte-Marie, Nina. "A transmission-error-based gear dynamic model : Applications to single- and multi-mesh transmissions." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSEI133/document.
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Les spectres de bruit mesurés en cabine d’hélicoptère montrent que la boîte de transmission principale (BTP) est un des principaux contributeurs au bruit perçu par les usagers. Elle génère en effet plusieurs raies émergeant fortement du bruit large bande et dont les fréquences se situent dans la plage de sensibilité maximale de l’oreille humaine. Dans un contexte d’amélioration permanente du confort acoustique des usagers, un modèle numérique est développé pour prédire le comportement dynamique des BTP. Les équations du mouvement sont écrites sur la base de fonctions du temps représentatives des excitations générées par l’engrènement (raideur d’engrènement et erreurs de transmission). Plusieurs éléments de validation sont présentés pour confirmer la pertinence de la formulation proposée. Différents résultats numériques et expérimentaux de la littérature sont utilisés à des fins de comparaison, montrant que le modèle s’applique aux systèmes à simple étage de réduction, par engrenage cylindrique ou spiro-conique. La validation est ensuite étendue aux systèmes à deux étages de réduction et les résultats confirment que la formulation basée sur les erreurs de transmission permet de tenir compte des corrections de profil. Finalement, le modèle est utilisé pour diverses applications. Premièrement, l’influence des erreurs de pas sur le comportement dynamique de transmissions par engrenages est discutée, ainsi que l’influence combinée du niveau de chargement appliqué. Dans un second temps, la relation entre l’erreur de transmission dynamique et différents coefficients dynamiques est étudiée. Le contenu spectral de la réponse au niveau des roulements est ensuite analysé pour des systèmes à deux engrènements cylindriques et l’influence de différents paramètres est discutée. Enfin, une application est réalisée sur un système comprenant un engrenage cylindrique et un engrenage spiro-conique. Les phénomènes de couplage entre les étages successifs sont mis en évidence ainsi que la contribution des deux engrènements au contenu spectral de la réponse aux roulementsNoise measurements have shown that helicopters main gearboxes highly contribute to the overall cabin noise. Gear mesh vibrations propagate through the shafts to the rolling element bearings and the casing which becomes a source of radiated noise. The latter is characterized by high-amplitude tones emerging from broadband noise whose frequencies lie in the range of maximum human ear sensitivity. In the context of continuous improvement in the acoustic comfort of helicopter passengers, it is therefore necessary to analyse and optimize gearbox vibrations in order to reduce casing noise radiations. The research work presented in this memoir is focused on the development of a numerical model dedicated to the prediction of gear system dynamic behaviour, comprising several gear stages and different types of gears. This model relies on classic beam and lumped parameter elements along with specific two-node gear elements for both cylindrical (spur, helical) and spiral-bevel gears. The equations of motion are developed based on time-varying functions representative of mesh excitations which comprise: (a) mesh stiffness functions, (b) quasi-static transmission error under load, and (c) kinematic (or no-load) transmission error. A number of comparisons with benchmark numerical and experimental results from the literature are presented which demonstrate that the proposed approach is sound as far as single-stage systems with spur, helical or spiral-bevel gears are considered. Validations are then extended to double-stage gears and, here again, it is confirmed that the proposed transmission error based formulation is accurate and can account for tooth shape modifications. In the second part of the memoir, several examples of application are presented and commented upon. First, the combined influence of tooth pitch errors and load on the dynamic behaviour of gear transmissions is tackled. An extended three-dimensional model and a reduced torsional version are then confronted in order to investigate the dependency between dynamic transmission errors and mesh force / root stress dynamic factors. Further investigations on bearing dynamic response in two-stage spur gear systems are conducted and the particular contributions of profile modifications are analysed. Finally, a system combining a cylindrical gear and a spiral-bevel gear is considered and particular attention is paid to the dynamic couplings between the various meshes and their influence on bearing dynamic responses
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Shimizu, H., Y. Yokomizu, T. Kato, Y. J. Tang, T. Matsumura, Y. Kito, K. Satoh, and W. Satoh. "Transmission loss of prospective power transmission model system integrated under superconducting environment." IEEE, 1997. http://hdl.handle.net/2237/6804.
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Fohrmann, Andy. "Patterns of livestock-pathogen transmission and emergence : a framework for categorising transmission." Thesis, University of Liverpool, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.569886.
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Infectious diseases continue to cause significant financial, economic and health issues. Much work has been done on a variety of pathogens and host species with a wide range of approaches and methodologies from many disciplines, yet a full understanding of pathogen emergence has not been achieved. A greater understanding of transmission would benefit the management of control strategies, help to improve decision-making at first diagnosis of a host-pathogen interaction and possibly prevent further spread of epidemics and therefore new cases of emergence. A major gap in all these efforts appears to be a comprehensive, detailed approach for categorising pathways of transmission. Here, I develop and present a framework to categorise transmission events of pathogens. I use this framework to review the available literature on the transmission of pathogens of seven livestock species, and to derive intra- as well as inter-species transmission routes or pathways by which pathogens may emerge and infect the livestock hosts. A general dataset of the livestock pathogens was constructed, containing information on 141 bac- terial and viral pathogen species. One finds these pathogens exploit 7204 distinct transmission routes between 215 different host species. Analysis of this dataset verifies the dominance of multi- host pathogens, and suggests that non-close or indirect transmission routes tend to be associated with larger host range. The data shows the faecal-oral transmission mode is the predominant transmission pathway for livestock infection. To attempt to link features of species-scale transmission routes with emergence rates, a second dataset was constructed. This was a more detailed description of twelve Salmonella enterica serovars, and holds 1716 distinct transmission routes, llO distinct host species. One finds t.he connectedness of a host species within its network of transmission routes is associated to its po- tential for acquiring Salmonella infection. Analysis of both datasets highlights the substantial importance of anthropogenic mechanical vectors such as food and feedstuffs for the emergence of infectious disease in both humans and livestock animals. The developed framework demonstrably captures important aspects of pathogen emergence, al- though there are limitations in the quality and availability of information required to generate the datasets. The networks of transmission routes derived using this framework show common features and structural properties which may explain emergence potential. It is hoped that, by adopting this framework, the scientific community can improve the understanding of the drivers of transmission and emergence of these important pathogens.
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Iwelski, Stanislaus [Verfasser]. "Reliable Downlink Transmission in Unsynchronized Coordinated Multipoint Transmission LTE Networks / Stanislaus Iwelski." München : Verlag Dr. Hut, 2019. http://d-nb.info/1181516536/34.
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Martin, Sainz de la Maza Oihane. "Leishmaniasis transmission biology : role of Promastigote Secretory Gel as a transmission determinant." Thesis, London School of Hygiene and Tropical Medicine (University of London), 2014. http://researchonline.lshtm.ac.uk/1775854/.
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Leishmaniasis is a complex vector-borne disease caused by Leishmania sp. (Kinetoplastida: Trypanosomatidae) and is transmitted by female sand flies (Diptera: Psychodidae). It is endemic in 88 countries where the prevalence is 12 million and 350 million people are at risk. The study of vector biology is essential to understand leishmaniasis epidemiology and to implement cost-effective vector control measures. This thesis aims to describe the role of Promastigote Secretory Gel (PSG) in disease transmission. Transmission is a crucial event in the Leishmania life cycle, requiring sufficient infective metacyclic promastigotes to be injected in the host by sand fly bite in a favourable ecotope. PSG is produced by immature Leishmania forms within the female sand fly gut and it is comprised of filamentous proteophosphoglycan (fPPG). It is known to modify sand fly behaviour. Here, we investigate its biological role in development and enhancement of transmission by parasite selection using a Lutzomyia longipalpis-Leishmania mexicana experimental model. Briefly, a Lutzomyia longipalpis colony was established and maintained at LSHTM and all parasite developmental forms were generated. PSG was obtained from experimentally infected flies. PSG role in development, specifically in attachment and detachment of promastigotes to the midgut, was studied by ex vivo competitive midgut binding. The role of PSG in parasite selection was studied by in vitro PSG slide attachment, capillary migration and parasite video-tracking. In order to study the underlying binding mechanisms to both PSG and midgut, mutant parasites were used. Ligand analysis was completed by Western Blotting. PSG was found to favour promastigote detachment from the midgut and thus, parasite migration and maturation. It binds to immature parasitic forms and not to infective metacyclic promastigotes, creating a biological sieve that retains immature forms and enriches the bite for metacyclics. Collectively, the results show that PSG is an essential vector competence determinant allowing successful transmission.
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Salim, Zakia. "De la transmission scolaire à la transmission familiale : modes d'articulation des savoirs." Toulouse 2, 1985. http://www.theses.fr/1985TOU2A003.
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Campos, Jose Carlos da Costa. "Matrizes de transformação reais aplicadas as linhas de transmissão de circuito duplo." [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/260914.
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Orientadores: Jose Pissolato Filho, Afonso Jose do PradoTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação
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Resumo: As matrizes de transformação reais e constantes são aplicadas como matrizes de transformação fase-modo características de um sistema simétrico com circuito trifásico duplo transposto e de duas linhas de transmissão paralelas transpostas com circuito trifásico duplo. Essas matrizes de transformação reais e constantes são baseadas na matriz de Clarke. Usando a combinação linear dos elementos da matriz de Clarke, as técnicas aplicadas para linhas trifásicas simples são ampliadas para sistemas com 6 e 12 condutores de fase. Para uma linha trifásica dupla transposta, as matrizes Z e Y são convertidas em matrizes diagonais no domínio dos modos. Considerando um caso não transposto de uma linha trifásica dupla, os resultados não são exatos e as análises de erros são realizadas mediante os autovalores. No caso de duas linhas trifásicas paralelas duplas e transpostas, a matriz de transformação exata com elementos reais e constantes não foi obtida ainda. Para esse caso, como sugestão para desenvolvimento futuro, a determinação da matriz de transformação modal real e constante provavelmente deverá ser baseada em uma única referência homopolar. Tal sugestão se deve ao fato de que, neste trabalho, a estrutura das matrizes de transformação utilizadas tem como base a aplicação do modo homopolar como única referência homopolar para todos condutores de fase do sistema estudado.
Abstract: Single real transformation matrices are applied as phase-mode transformation matrices of typical symmetrical systems with double three-phase and two parallel double three-phase transmission lines. These single real transformation matrices are achieved from eigenvector matrices of the mentioned systems and they are based on Clarke's matrix. Using linear combinations of the Clarke's matrix elements, the techniques applied to the single three-phase lines are extended to systems with 6 or 12 phase conductors. For transposed double three-phase lines, phase Z and Y matrices are changed into diagonal matrices in mode domain. Considering non-transposed cases of double three-phase lines, the results are not exact and the error analyses are performed using the eigenvalues. In case of two parallel double three-phase lines, the exact single real transformation matrix has not been obtained yet. Probably, for two parallel double three-phase lines, considering future development and searching for the exact single real transformation matrix, the analyses are based on a single homopolar reference. This suggestion is related to that in the all analyses carried out in this work, the homopolar mode is used as the only homopolar reference for all phase conductors of the studied system.
Doutorado
Energia Eletrica
Doutor em Engenharia Elétrica
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Bilbao, Héctor Uhalte. "DAB Transmission System Simulation." Thesis, Linköping University, Department of Electrical Engineering, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-2595.
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DAB (Digital Audio Broadcasting) is the radio digital system developed as an european standard by the ETSI, EN 300 400, based on the Eureka-147 group works, to improve the performance of the analogue radio systems (AM and FM). The system is based on the OFDM technology which allows DAB to exploit the spectrum frequencies in a better way with a higher quality of sound for mobile receivers specially. The main part of the OFDM system is based on the FFT algorithms to spread the data flow over different orthogonal carriers. The simulation has been developed in SimulinkTMand MatlabTMand the layout designed follows faithfully the standard for the transmission system. The simulation can be reloaded by the user with the information presented in this thesis. Thus, this work can be continued to complete the DAB whole system simulation. The results obtained running this simulation show the main DAB system characteristics.
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Lapohos, Tibor. "Multiconductor transmission line networks." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0012/NQ31123.pdf.
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Marotta, Susana. "Intergenerational transmission of abuse." Click here for text online. The Institute of Clinical Social Work Dissertations website, 2002. http://www.icsw.edu/_dissertations/marotta_2003.pdf.
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Dissertation (Ph.D.) -- The Institute for Clinical Social Work, 2002.A dissertation submitted to the faculty of the Institute of Clinical Social Work in partial fulfillment for the degree of Doctor of Philosophy.
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Salous, Mounther N. H. "Context-based image transmission." Thesis, University of Birmingham, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.368121.
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ALMEIDA, JORGE VIRGILIO DE. "VIRTUAL MAGNETIC TRANSMISSION LINES." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2017. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=32030@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
Nos últimos anos, tem aumentado o interesse no uso da transmissão de energia sem fio por acoplamento indutivo em muitas aplicações. Uma das maiores limitações dessa tecnologia é a distância de operação reduzida. Alguns trabalhos recentes sugerem usar materiais artificiais conhecidos como metamateriais para aprimorar a eficiência da transferência de potência ao longo da distância. Devido às suas propriedades eletromagnéticas únicas, tais como permeabilidade magnética negativa, metamateriais podem ser usados para amplificar as ondas evanescentes do campo próximo. No presente trabalho, é estudado o uso de metamateriais eletromagnéticos para aumentar o acoplamento indutivo por meio da amplificação do campo próximo. São apresentados cálculos analíticos e simulações dos metamateriais propostos. O melhoramento da eficiência na transferência de potência é apoiado por evidências experimentais.
Over recent years, the interest in using inductive wireless power transmission for many applications has grown. One of the major limitations of this technology is the reduced operating distance. Some recent works have suggested using artificial materials known as metamaterials to improve the power transfer efficiency over distance. Due to their unique electromagnetic properties, such as negative permeability, metamaterials can be used to enhance the evanescent waves of the near field. In the present work, the usage of an electromagnetic metamaterial to increase the inductive coupling by means of enhanced evanescent waves is studied. Analytical calculations and numerical simulations of the proposed metamaterial are presented. The improvement of the power transfer efficiency is supported by empirical evidences.
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Becker, Matthew E. (Matthew Erin). "Resonant transmission line drivers." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/81519.
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Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2000.Includes bibliographical references (leaves 71-72).
by Matthew E. Becker.
Ph.D.
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Yang, Xiaofei. "Inferring disease transmission networks." HKBU Institutional Repository, 2014. https://repository.hkbu.edu.hk/etd_oa/88.
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To investigate how an infectious disease spreads, it is desirable to use the observed surveillance data to discover the underlying (often hidden) disease transmission networks. Previous studies have provided methods for inferring information diffusion networks in which each node corresponds to an individual person within the diffusion network. However, in the case of disease transmission, to effectively propose and implement intervention strategies, it is more realistic and reasonable for policy makers to study the diffusion patterns at a metapopulation level, that is, to consider disease transmission networks in which nodes represent subpopulations, and links indicate their interrelationships. Such networks can be useful in several ways: (i) to investigate hidden impact factors that in.uence epidemic dynamics, (ii) to reveal possible sources of epidemic outbreaks, and (iii) to practically develop and/or improve strategies for controlling the spread of infectious diseases. Therefore, this thesis addresses the problem of inferring disease transmission networks at a metapopulation level. A network inference method called NetEpi (Network Epidemic) is developed and evaluated using both synthetic and real-world datasets. The experimental results show that NetEpi can recover most of the ground-truth disease transmission networks using only surveillance data.
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Thompson, William David. "Transmission, induction and evolution." Thesis, University of Edinburgh, 2015. http://hdl.handle.net/1842/11766.
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Many human behaviours are thought to depend upon cognitive capacities enriched with innate domain-specific knowledge. Underpinning this view is the hypothesis that evolution can shape cognition to include strong innate inductive biases. In this thesis, I re-examine that hypothesis with respect to a broad class of behaviours: those that we learn from other individuals. Taking human language as a test case, I present an analysis of the co-evolutionary process that underpins the formation of innate constraints on cognition for behaviours that are culturally transmitted through inductive inference. I derive a series of mathematical models of this process, built around Bayesian models of cognition and cultural transmission, and ask how they can inform our expectations about cognition in a cultural species. I argue that the traditional marriage of nativism and evolutionary reasoning is undermined by this process, as is the suggestion that cognitive adaptation to cultural behaviours is outright implausible. I explore the co-evolutionary dynamics induced by cultural transmission, and conclude that they can radically manipulate the evolution of cognition: culture can intervene in the formation of hard-wired knowledge, but nevertheless facilitate rapid cognitive adaptation. The analyses I report make strong, testable predictions about the nature of inductive biases for cultural behaviours, and offer solutions to a number of long-standing conundrums in the evolution of language.
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Warren, Darren A. (Darren Allen). "Mechanisms of Synaptic Transmission." Thesis, The University of Sydney, 1996. https://hdl.handle.net/2123/27620.
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In this work we have presented the results of studies into the mechanisms of synaptic transmission in the sympathetic
nervous sytem. This work has involved calcium imaging on chick ciliary ganglion cells, intracellular recording from rat
main pelvic ganglion cells and extracellular recordings from visualised boutons in the rat main pelvic ganglion.
Using digital imaging techniques, we studied the changes in cell calcium concentration in the avian ciliary ganglion
following tetanic stimulation. The results showed a 3 fold increase for a short tetanus or a 4 fold increase for a long
tetanus in the calcium concentration of both the calyx and soma. After a long tetanus the calcium concentration then
declined along a double exponential with a time course similar to that of post-tetanic potentiation and long term
potentiation in the ganglia.
A new technique has been developed for recording the electrical signs of transmission at single boutons in the sympathetic nervous system. This technique allows recording and
comparison of the relative amplitude of the presynaptic action potential, electrical signs of transmitter release and
postsynaptic action potential from single or small groups of boutons. The preparation used for this work was the rat main pelvic ganglion.
Extracellular electrodes placed over visualized boutons revealed evoked excitatory postsynaptic potentials (extracellular EPSP's) with amplitude histograms that were best described by single gamma distributions in most cases inlow [Ca2+]o (less than 0.5 mM). However, in some cases the gamma distribution had a very large variance which may
have been due to the synchronous release of transmitter from closely apposed boutons which were observed under a
confocal microscope. Intracellular electrodes used on the same preparation revealed spontaneous excitatory
postsynaptic potentials (EPSP’S) with amplitude histograms which were in general well fitted by a Poisson mixtures of
gamma distributions over a wide range of calcium concentrations.
Using the technique of extracellular recording from single boutons or small numbers of boutons we were able to
conclude that K-opioid receptors are located on the boutons of the hypogastric nerve. When activated by K—opioid
receptor agonists they reduce quantal secretion without affecting the propagation of the nerve impulse along the
hypogastric nerve.
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Ludi, Paul Anthony. "Smuts : Lost in Transmission?" Diss., University of Pretoria, 2016. http://hdl.handle.net/2263/60380.
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This dissertation examines the transmission of the past and how it is affected by context, source materials, and the individual with regards to opinion and inherent bias. The subject of this analysis is Jan Christiaan Smuts and how he has been portrayed over the last century. Various authors are analysed with W. K. Hancock forming a kind of watershed given the access to primary material. The dissertation includes a brief discussion of South African historiography as well as a brief biographical outline of Smuts's life. The main concern is however a literature analysis of selected material which will set out to illustrate how information is often "lost in transmission."Dissertation (MHCS)--University of Pretoria, 2016.
Historical and Heritage Studies
MHCS
Unrestricted
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Ericsson, Elias. "Adaptive Wireless Transmission System." Thesis, Uppsala universitet, Institutionen för teknikvetenskaper, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-385400.
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Cazzaro, Pablo Martins. "Análise da dinâmica dos investidores nos leilões de transmissão de energia elétrica no Brasil entre 1999 e 2017." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/106/106131/tde-19022018-202041/.
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O segmento de transmissão de energia elétrica é parte fundamental na composição de qualquer sistema elétrico de potência, e tem como principal função o transporte da energia elétrica dos polos geradores até os centros consumidores. Neste contexto, o objetivo principal desta dissertação é analisar a participação dos agentes investidores do mercado de transmissão de energia elétrica no Brasil, observando o perfil daqueles que venceram os leilões de transmissão, sob o aspecto de sua governança no tocante à natureza do capital público ou privado, nacional ou estrangeiro. Como questão central, indaga-se como vem se dando a dinâmica do mercado de transmissão de energia elétrica no país, através da análise dos vencedores dos certames de concessão do serviço público de transmissão. A pesquisa aborda ainda elementos que resgatam a importância técnica e econômica da transmissão, sua evolução histórica e as regras de concessão então vigentes no país, além de realizar um levantamento dos leilões de transmissão entre os anos de 1999 a agosto 2017. Visando a reestruturar o setor elétrico brasileiro a partir da década de 1990, um modelo então formulado possibilitou a expansão do sistema de transmissão por meio de concorrências na exploração de concessões públicas do serviço de transporte de energia elétrica. Tal modelo finalmente permitiu que companhias de capital privado, nacional ou estrangeiro, pudessem participar dessa expansão. Entre dezembro de 1999 e agosto de 2017 ocorreram 45 certames, nos quais culminou em uma expansão significativa da malha de transmissão no país, que passou de 66,9 mil km, antes dos referidos leilões, para mais 134,7 mil km, até o ano de 2016. Das centenas de investidores que arremataram os lotes disponibilizados, verificou-se que 89% deles eram de natureza privada e 11%, de natureza pública. Ainda, através da pesquisa realizada, constatou-se que 60% dos lotes negociados foram arrematados por investidores não-consorciados, mesmo diante das vantagens da formação de consórcios na criação de grupos considerados mais robustos financeira e tecnicamente. Os resultados desta investigação também revelaram que os grupos estrangeiros privados não-consorciados foram os que mais se destacaram, obtendo 25,2% das vitórias nos certames, e agregando 24,4% do total das linhas ofertadas em termos de extensão. Ademais, esses grupos estrangeiros privados não-consorciados mostraram-se mais competitivos, com lances que representaram deságios médios de 30,7%, arrematando projetos com potencial de rendimento anual de R$ 2,8 bilhões. Entretanto, por meio da investigação realizada, ainda se constatou que os investidores nacionais públicos não-consorciados continuaram muito influentes, pois: (i) deram lances com deságios também significativos, da ordem de 27,1% na média do período analisado; e (ii) alguns desses investidores nacionais públicos foram os vencedores mais frequentes, seja na forma não-consorciada ou consorciada, como foi o caso da Chesf, com 34 lotes arrematados, seguida de Furnas, com 26 lotes negociados.The segment of electric power transmission is a fundamental part of any electric power system, and its main function is to transport the electric power from the generating poles to the consumer centers. In this context, the main objective of this dissertation was to analyze the participation of the investors of the electricity transmission market in Brazil, observing the profile change of those who won the transmission auctions, among which were public, private, national and foreign agents. This dissertation targeted to answer the following central question: how was the market dynamic of the electric power transmission in the country taking into consideration the change in the profile of the agents who won the auctions? The research also explored the technical and economic importance of transmission, its historical evolution, the currently rules for concession in the country, as well as the characteristics of transmission auctions conducted between 1999 and August 2017. In order to restructure the Brazilian electric sector from the 1990s onwards, a model was formulated to made possible to expand the transmission system by competitive bidding in the exploration of public concessions for the electric energy transmission service. That model finally allowed domestic and foreign private equity companies to participate in this expansion. Between December 1999 and August 2017, there were 45 auctions and hundreds of lots were put to dispute. Consequently, there was a significant expansion of the transmission network in the country, from 66.9 thousand km before the auctions to a further 134.7 thousand km, until the year 2016. Of the hundreds of investors who purchased the lots available, 89% were private and 11% public. Also, through the research, it was found that 60% of the lots traded were sold by non-consortium investors, even considering the advantages of consortium to create groups financially and technically robust. The results of this investigation also revealed that the not consorted foreign private groups were the most outstanding, obtaining 25.2% of the victories in the auctions, and, adding 24.4% of the total of the offered lines in terms of extension. Furthermore, these foreign private groups were more competitive with bids that represented average discounts of 30.7%, earning projects with potential annual income of R $ 2.8 billion. However, the research also verified that not consorted national public investors are still very influential: (i) they made bids with significant discount, of the order of 27.1% in the average of the analyzed period; and (ii) some of these national public investors were the most frequent winners, either in the non-consortium or consortium form, as was the case of Chesf, with 34 lots acquired, followed by Furnas, with 26 lots traded.
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Chandra, Mariswamy Girish. "A new binary transmission scheme for improving the performance of digital transmission systems." Thesis, Imperial College London, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.409394.
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van, der Merwe J. "Simplified approach for the reliability estimation of large transmission and sub-transmission systems." Master's thesis, University of Cape Town, 2014. http://hdl.handle.net/11427/9093.
Full textAbstract:
Includes bibliographical references.Various specialised power system reliability modelling software are commercially available to analyse the expected performance of a utility’s transmission and sub-transmission network. The software requires a physical network model to be constructed, representing all network components. A high level of accuracy is obtained using such software, but significant effort is required to create these models, especially when large utility-scale networks are modelled. Another limitation of the software is that specific design strategies can only be modelled by physically changing the network model, which again requires significant effort. A simplified approach is therefore required to enable utility engineers to analyse the reliability of different network configurations, reliability improvement strategies and planning criteria. The aim of this research is to provide a simplified reliability approach that will assist engineers in managing the reliability of their transmission and sub-transmission networks. The approach should be simplified to require minimum user inputs and it should be capable of quantifying the impact of different substation and line configurations on a system level. It is not expected that this approach will have the same level of accuracy as the detailed software models, but it should enable engineers to calculate system indices with much less effort, while still maintaining an acceptable level of accuracy. The scope of this research is limited to the transmission and sub-transmission networks (lines and substations). Power stations and MV distribution feeders are excluded from the analysis. Only technical, customer-based performance indicators are modelled, no load-based or economic performance indicators are calculated. An analytical approach is considered for the simplified reliability modelling, starting with a failure mode and effect analysis. The contribution of substation and sub-transmission events is decoupled and a detailed model of the substation is created, including all internal components. A reliability analysis is performed for each substation, to determine the unavailability experienced by customers connected to each busbar. An equivalent system model is then generated by replacing all substations with busbars, of which the outage frequency and outage duration are equal to that of the substation equivalent. The simplified substation reliability estimation is compared with detailed substation modelling using specialised software. The results obtained with the simplified reliability estimation show a good correlation with the detailed software models. The simplified reliability methodology was programmed into MS Excel and used to model the expected availability of the Ghana transmission network. Different scenarios were then modelled, analysing the impact of design and operational changes on the expected reliability of the network. The simplified reliability model developed through this research is capable of calculating system level technical performance indices for utility-scale networks, requiring much less effort than detailed software models, but still providing an acceptable level of accuracy. The technical system indices (SAIDI and SAIFI), calculated by means of the simplified reliability approach, provide an indication of the technical performance of the network, but they do not provide information on the economic impact of network outages. These technical indices have the potential to result in funding decisions that are not closely linked to economic interest. For this purpose economic indices are required, and it is recommended that the approach be extended to include the calculation of economic indices.
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Romano, de Paula Valéria. "Social networks as a trade-off between optimal information transmission and reduced disease transmission." Thesis, Strasbourg, 2017. http://www.theses.fr/2017STRAJ056/document.
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La structure sociale d'un groupe peut théoriquement réguler la transmission des informations et le risques de maladies via les contacts sociaux et la proximité. En théorie, les mêmes propriétés de réseau qui favorisent la transmission d'information favorisent également la transmission de pathogènes, créant de fait un potentiel compromis entre eux. Dans ma thèse, j'ai utilisé des données empiriques, des analyses de réseaux et modèle de simulation individuel afin de comprendre l'influence des structures sociales sur la transmission sociale chez les primates et dans des réseaux théoriques. Mes études ont montré que i) les macaques japonais centraux dans Je groupe transmettent les pathogènes plus rapidement mais sont également plus susceptibles d' être infectés; ii) le nombre d'individus infectés dans 40 groupes de primates est dépendant des propriétés globales du réseau et de l'étape de l'infection: iii) un pic d'efficacité de réseau à des valeurs intermédiaires de sous structure de groupe dans des réseaux empiriques et théoriques ; et iv) des variations dans les propriétés de réseaux sont la conséquence de décisions individuelles en fonction de compromise entre la collecte d'information et l'évitement de l'infection. Ainsi, ma thèse a démontré les mécanismes de transmission social et indiqué que les propriétés de réseau pourrait réflecter un compromise entre transmission de l'information et transmission de pathogèneSocial structure can theoretically regulate information transmission and disease risk via social contact or proximity. In theory, the same network properties that favor information transmission also favor pathogen transmission creating a potential trade-off between them. In my thesis, I used empirical data, network analysis and individual-based modelling to understand the influence of social structure on social transmission in primate and theoretical networks. My studies show that i) central Japanese macaques transmit disease faster but are also more prone to acquiring infectious agents; ii) the number of infected individuals in 40 wild primate groups is dependent on global network properties and epidemic time; iii) network efficiency peaks with intermediate values of group substructure in theoretical and empirical networks; and, iv) variation in the network properties is a consequence of individual decisions given the trade-offs between collecting information and avoiding infection. Altogether, my thesis reveals the mechanisms of social transmission and indicates that network properties might reflect a trade-off between information and pathogen transmission
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Perras, Stefan. "Electricity transmission line planning: Success factors for transmission system operators to reduce public opposition." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-161770.
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Europe requires significant transmission grid expansions to foster the integration of electricity markets, enhance security of supply and integrate renewable energies. However, next to lengthy authorization processes, transmission system operators (TSOs) in Europe are currently facing extreme public opposition in their transmission line projects leading to significant project delays. These delays imply significant additional costs for TSOs as well as society as a whole and put the transformation of the European energy system at risk. Existing scientific literature currently lacks comprehensive studies that have tried to identify generalizable success factors to overcome public opposition in transmission line projects. The goal of work at hand was to close this research gap. Potential success factors were collected through extensive literature review and interviews throughout Europe with respective stakeholders such as citizen action groups, NGOs or energy experts. Experiences from analogue large infrastructure projects like wind parks, carbon capture and storage facilities, hydro dams, nuclear waste repositories, etc. were also used to form hypotheses. The findings were transformed into a structural equation model and tested through a questionnaire answered by almost all European TSOs.
Results revealed that people’s trust in the TSO is of utmost importance for less public opposition. It can be regarded as the critical success factor per se. TSOs can create trust through stakeholder participation, sufficient communication, proper organizational readiness and liaison with stakeholders. Furthermore, appropriate technical planning can help to reduce public opposition in transmission line projects. In total 18 concrete and actionable success factors were identified for TSO management to facilitate the establishment of these aforementioned aspects. They will help European TSOs to reduce public opposition and thus accelerate the implementation of new transmission lines. Interestingly, economic benefits for people did not turn out to be a Significant success factor in reducing their opposition against new transmission lines.
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ALID, MOSTAFA. "Transmission de donnees sur canaux selectifs en frequence : application aux transmissions sur canal acoustique sous-marin." Rennes 1, 1993. http://www.theses.fr/1993REN10059.
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Le besoin de transmettre des donnees sur canal acoustique sous-marin horizontal (portee de quelques kilometres) par petites fonds (quelques dizaines de metres de hauteur d'eau) est ressenti, autant dans le domaine scientifique (collecte de donnees environnementales sous-marines) que par le grand public (communication entre plongeurs amateurs). Pour ce type de canal, la propagation des ondes acoustiques se fait en general suivant plusieurs trajets, attenues aleatoirement ou non (canal de rayleigh ou de rice) et affectes d'un effet doppler. Le produit de la dispersion temporelle des instants d'arrivees des trajets et par la frequence doppler maximale, peut etre superieur a l'unite. Dans cette these, nous proposons d'utiliser un multiplex a division de frequence module en amplitude (par tout ou rien) ou en frequence, et un recepteur non coherent pour eviter les problemes de recuperation de porteuse. En choisissant un intervalle de garde entre chaque symbole emis, on montre qu'il est possible de realiser une transmission sans interference entre symboles. Pour s'affranchir de l'effet doppler, dont la valeur peut dans notre cas, etre superieure a la rapidite de modulation, un recepteur de type quadratique a ete utilise. Ce recepteur analyse le signal recu selon plusieurs tranches temporelles sur lesquelles le canal de transmission est suppose stationnaire. Nous avons evalue les performances du recepteur quadratique en fonction des parametres du canal. Les resultats montrent que sous certaines conditions l'effet doppler et les trajets multiples apportent une diversite implicite que le recepteur quadratique arrive a exploiter
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Boone, Johnathan. "Three essays concerning information transmission." Diss., [La Jolla] : University of California, San Diego, 2010. http://wwwlib.umi.com/cr/ucsd/fullcit?p3397279.
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Thesis (Ph. D.)--University of California, San Diego, 2010.Title from first page of PDF file (viewed March 29, 2010). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references.
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Magrans, Fontrodona Francesc Xavier. "Vibroacoustic coupling and transmission paths." Doctoral thesis, Universitat Politècnica de Catalunya, 2018. http://hdl.handle.net/10803/664633.
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This dissertation deals with four topics. The first three are in the same environment, the transmission paths. The fourth refers to the synthesis of subsystems and more specifically to two subsystems linked by any number of elastic elements.
In the first topic it is proved that the solution of any linear mechanical system can be expressed as a linear combination of signal transmission paths. This is done in the framework of the Global Transfer Direct Transfer (GTDT) formulation for vibroacoustic problems. Transmission paths are expressed as powers of the transfer matrix. The key idea of the proof is to generalise the Neumann series of the transfer matrix ,which is convergent only if its spectral radius is smaller than one, into
a modified Neumann series that is convergent regardless of the eigenvalues of the transfer matrix. The modification consists in choosing the appropriate combination coefficients for the powers of the transfer matrix in the series. A recursive formula for the computation of these factors is derived. The theoretical results are illustrated by means of numerical examples. Finally, we show that the generalised Neumann series can be understood as an acceleration of Jacobi iterative method.
For complex geometries, the definition of the subsystems is not a straightforward task. We present as a second topic a subsystem identification method based on the direct transfer matrix, which represents the first-order paths. The key ingredient is a cluster analysis of the rows of the powers of the transfer matrix. These powers represent high-order paths in the system. Once subsystems are identified, the proposed approach also provides a quantification of the degree of coupling between subsystems. This information is relevant to decide whether a subsystem may be analysed independently of the rest or subsystems or not. The two features (subsystem identification and quantification of the degree of coupling) are illustrated by means of numerical examples: plates coupled by means of springs and rooms connected by means of a cavity.
In the third work, Advanced Transfer Path Analysis (ATPA) is applied to a cuboid-shaped box. The simplicity of this vibroacoustic system helps to make a detailed analysis of the ATPA method in a more controlled environment than in situ measurements in trains, wind turbines or other mechanical systems with complex geometry, big dimensions and movement. At the same time, a numerical model (based on finite elements) of the box is developed. The agreement between the experimental measurements and the numerical results is good. The numerical model is used in order to perform tests that cannot be accomplished in practise. The results are helpful in order to verify hypotheses, provide recommendations for the testing procedures and study some aspects of ATPA such as the reconstruction of operational signals by means of direct transfer functions or to quantify and understand which are the transmission mechanisms in the box.
The fourth topic introduces a method to synthesize the modal characteristics of a system from the modal characteristics of its subsystems. The interest is focused on those systems with elastic links between the parts which is the main feature of the proposed method. An algebraic proof is provided for the case of arbitrary number of connections. The solution is a system of equations with a reduced number of degrees of freedom that correspond to the number of elastic links between the subsystems.
In addition the method is also interpreted from a physical point of view (equilibrium of the interaction forces). An application to plates linked by means of springs shows how the global eigenfrequencies and eigenmodes are properly computed by means of the subsystems eigenfrequencies and eigenmodes.Aquest treball estudia quatre temes. Els tres primers estan en el àmbit de les vies de transmissió. El quart fa referencia a la síntesi de subsistemes i mes concretament a dos subsistemes lligats per un nombre qualsevol de molles. En el primer treball es demostra que la solució de qualsevol sistema mecànic lineal es pot expressar com una combinació lineal de vies de transmissió de senyal. Això es fa en el marc de la formulació per problemes vibroacústics del Global Transfer Direct Transfer (GTDT). Les vies de transmissió s'expressen com les potencies de la matriu de transferències. La idea clau de la demostració es generalitzar la sèrie de Neumann aplicada a la matriu de transferència, que és una sèrie convergent només si el radi espectral és menor que u, amb una sèrie de Neumann modificada que convergeix amb independència del radi espectral de la matriu de transferència. La modificació consisteix en escollir els coeficients apropiats per a les potències de la matriu de transferència a la sèrie. Una fórmula recursiva facilita el càlcul. Els resultats teòrics s'il·lustren amb exemples numèrics. Finalment es mostra que la sèrie de Neumann generalitzada es pot aplicar per accelerar el mètode iteratiu de Jacobi. En geometries complexes, la definició dels subsistemes no es directe. Com a segon tòpic es presenta un mètode per a identificar els subsistemes que es basa en la matriu de transferència que representa els camins de primer ordre. La clau es un estudi clúster de les files de les potencies de la matriu de transferència. Aquestes potencies representen els camins d'ordre superior en el sistema i són més afectats per l'esmorteïment que els camins d'ordre inferior. Quan el subsistemes estan identificats, el mètode proposat també dona una quantificació del grau d'acoblament entre els subsistemes. Aquesta informació és important per decidir quan un subsistema es pot analitzar amb independència de la resta de subsistemes. Les dues aplicacions (identificació i quantificació del grau d'acoblament,) s?il·lustren mitjanant exemples numèrics: plaques lligades amb molles i habitacions connectades per un forat. En el tercer treball s'aplica ATPA a una caixa. La simplicitat d'aquest sistema vibroacústic ajuda a poder fer una anàlisi detallada del mètode ATPA en un entorn més controlat que el que es disposa amb assaigs en trens, turbines eòliques o altres sistemes mecànics de geometria complexa, grans dimensions i que estan en moviment. Es fa un model numèric basat en Elements Finits que correspon bé amb els assaigs fets sobre la caixa real. El model numèric s'empra per provar resultats del mètode que son difícils de demostrar en experiments reals, també per trobar procediments per limitar les imprecisions inevitables als assaigs i que poden afectar a la reconstrucció dels senyals en funcionament real i per aprofundir en els mecanismes de transmissió del senyal. El quart treball introdueix un mètode per a sintetitzar les característiques modals d'un sistema a partir de les característiques modals dels subsistemes. L'interès s'adreça als sistemes que tenen les seves parts lligades elàsticament sent aquest aspecte el factor diferencial. Es fa una demostració algebraica per a qualsevol nombre de connexions. El resultat és un sistema d'equacions de dimensió igual al nombre de connexions que, normalment, és molt inferior al nombre de graus de llibertat. El mètode s'interpreta a més des del punt de vista físic (equilibri entre les forces de interacció). Amb un exemple consistent en dues plaques lligades amb molles es demostra que freqüències i modes propis es calculen de forma adient.
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Zhao, Shengjie. "Video transmission over wireless networks." Diss., Texas A&M University, 2003. http://hdl.handle.net/1969.1/2225.
Full textAbstract:
Compressed video bitstream transmissions over wireless networks are addressed in this work. We first consider error control and power allocation for transmitting wireless video over CDMA networks in conjunction with multiuser detection. We map a layered video bitstream to several CDMA fading channels and inject multiple source/parity layers into each of these channels at the transmitter. We formulate a combined optimization problem and give the optimal joint rate and power allocation for each of linear minimum mean-square error (MMSE) multiuser detector in the uplink and two types of blind linear MMSE detectors, i.e., the direct-matrix-inversion (DMI) blind detector and the subspace blind detector, in the downlink. We then present a multiple-channel video transmission scheme in wireless CDMA networks over multipath fading channels. For a given budget on the available bandwidth and total transmit power, the transmitter determines the optimal power allocations and the optimal transmission rates among multiple CDMA channels, as well as the optimal product channel code rate allocation. We also make use of results on the large-system CDMA performance for various multiuser receivers in multipath fading channels. We employ a fast joint source-channel coding algorithm to obtain the optimal product channel code structure. Finally, we propose an end-to-end architecture for multi-layer progressive video delivery over space-time differentially coded orthogonal frequency division multiplexing (STDC-OFDM) systems. We propose to use progressive joint source-channel coding to generate operational transmission distortion-power-rate (TD-PR) surfaces. By extending the rate-distortion function in source coding to the TD-PR surface in joint source-channel coding, our work can use the ??equal slope?? argument to effectively solve the transmission rate allocation problem as well as the transmission power allocation problem for multi-layer video transmission. It is demonstrated through simulations that as the wireless channel conditions change, these proposed schemes can scale the video streams and transport the scaled video streams to receivers with a smooth change of perceptual quality.
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Törnqvist, David. "Transmission Timing in WCDMA terminals." Thesis, Linköping University, Department of Electrical Engineering, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-1592.
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Power control is one of the technologies used to utilize the radio resources as efficient as possible in WCDMA. The transmission power is adjusted to transmit with the lowest power level possible while the required received signal quality is maintained. Since there are large variation in channel quality over time, the power has to be adjusted to compensate for these variations. During moments of bad channel conditions a high transmission power has to be used which will to a greater extent interfere with other users in the system.
To solve this problem a concept called transmission timing was proposed. The basic idea is that the transmitter avoids data transmission during the short periods of bad channel conditions caused by fast fading. Higher bit rates can be used to compensate for this when the channel conditions are good.
In this thesis the performance of transmission timing applied to uplink data transmissions is evaluated. This is accomplished through a theoretical analysis as well as simulations of a cellular system using transmission timing. Lowered transmission power is achieved and thus lowered interference is induced. Simulations showed that the transmission power can be lowered by up to 1.6 dB compared to ordinary continuous transmission with equal average data rate. These results are however strongly dependent on the used radio environment. It is also showed that transmission timing provides increased system stability in case of rapid changes in the load situation.
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Gao, Qi. "Real-time Transmission Over Internet." Thesis, Linköping University, Department of Electrical Engineering, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-2169.
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With the Internet expansion, real-time transmission over Internet is becoming a new promising application. Successful real-time communication over IP networks requires reasonably reliable, low delay, low loss date transport. Since Internet is a non-synchronous packet switching network, high load and lack of guarantees on data delivery make real-time communication such as Voice and Video over IP a challenging application to become realistic on the Internet.
This thesis work is composed of two parts within real-time voice and video communication: network simulation and measurement on the real Internet. In the network simulation, I investigate the requirement for the network"overprovisioning"in order to reach certain quality-of-service. In the experiments on the real Internet, I simulate real-time transmission with UDP packets along two different traffic routes and analyze the quality-of- service I get in each case.
The overall contribution of this work is: To create scenarios to understand the concept of overprovisioning and how it affects the quality-of-service. To develop a mechanism to measure the quality-of-service for real-time traffic provided by the current best-effort network.