Global ETD Search

1	Selective Cooperation for Dual-Hop Cooperative Communication Networks Tsai, Tsung-hao 25 August 2010 (has links) In cooperative communications systems, multiple relays selection scheme and adaptive relay selection scheme are usually adopted. In both schemes, the system makes selections based on instantaneous channel status. However, such schemes have an extremely high computational complexity. In particular, when the channels experience fast fading, the systems do not have sufficient to make a correct decision. In this thesis, statistical channel properties are utilized in deciding whether cooperative transmission should be adopted or not. In our investigations, the cooperative mechanism includes direct transmission (DT), decode-and-forward (DF) relaying and amplify-and-forward (AF) relaying. The Ergodic capacity is adopted throughout the theoretical analyses. In addition, a number of approximated thresholds are derived to assist the decision process. Simulation experiments are conducted to verify the derived results. It is shown that the proposed transmission scheme using the cooperative thresholds is effective in deciding when the cooperative communication is necessary. cooperative thresholds amplify-and-forward decode-and-forward direct transmission
2	Modélisation et optimisation du contrôle de l’encéphalite japonaise au Cambodge / Modelling and optimization of japanese encephalitis control in Cambodia Diallo, Alpha Oumar II 27 November 2018 (has links) L’encéphalite Japonaise (EJ) est une maladie zoonotique virale et c’est la principale cause d'encéphalite humaine en Asie et le Pacifique. Elle est due à un Flavivirus, transmis de l’animal à l'Homme par des moustiques, elle peut se transmettre entre porcs par contact direct. Malgré une baisse significative des cas d’EJ dans de nombreux pays suite à la mise en place de programmes de vaccination, l’EJ continue à sévir d’une manière importante en Asie. Notre objectif dans cette thèse est de (i) construire un modèle mathématique de la dynamique de transmission du virus de l’EJ (VEJ), (ii) paramétrer ce modèle pour déterminer l’importance de la transmission directe entre porcs en milieu naturel (iii) et déterminer des stratégies de contrôle. Nous avons développé un modèle de propagation du VEJ. Ensuite, nous avons adapté ce modèle pour avoir deux modèles intégrant la transmission vectorielle seulement ou une combinaison de la transmission vectorielle et directe. Nos résultats montrent que la transmission directe entre porcs pourrait contribuer à la dynamique de transmission du VEJ dans le contexte Cambodgien, toutefois elle ne pourrait pas permettre toute seule une épidémie. Enfin, nous avons considéré la lutte anti-vectorielle, la vaccination des truies et la gestion d’élevages en bandes pour déterminer des stratégies de contrôle pour éradiquer le VEJ au sein des troupeaux de porcs, baisser les avortements des truies, évaluer les risques pour les humains vivant à proximité des fermes et des abattoirs ainsi que le coût-efficacité de la vaccination. Nos résultats confirment que la lutte anti-vectorielle est le meilleur moyen pour contrôler le VEJ. La vaccination des truies gestantes fait diminuer les avortements comme attendu. Paradoxalement, si le contrôle vectoriel est moyen l’efficacité de la vaccination pourrait être compromise. La gestion d’élevages en bandes a un faible impact sur l'incidence et les avortements, par conséquent sur le contrôle de l’EJ. Combiner la vaccination des truies et la lutte anti-vectorielle pourrait être une alternative et/ou une mesure supplémentaire à la vaccination humaine pour réduire à la fois l'incidence de l'EJ chez l'Homme et l'impact économique de l'infection du au VEJ dans les élevages des porcs. / Japanese encephalitis (JE) is a viral zoonotic disease and it is the leading cause of human encephalitis in Asia and the Pacific. Japanese encephalitis virus (JEV) is a Flavivirus of the family of Flaviviridae transmitted from animals to human by mosquitoes, direct transmission between pigs can occur via direct contact. Despite a significant decline in JE cases in many countries as a result of vaccination programs, JE continues to have a significant impact in Asia. Our objective in this thesis is to (i) built a mathematical model of the transmission dynamics of JEV, (ii) parameterize this model to determine the importance of direct transmission between pigs under field conditions (iii) and determine control strategies. We developed a propagation model of JEV. Next, we adapted this model to have two models incorporating vector-borne transmission alone or a combination of vector-borne and direct transmission. Our findings suggest that direct transmission between pigs does contribute to transmission dynamics of JEV in Cambodia; although, alone direct transmission cannot sustain an outbreak. Finally, we considered vector control, sow vaccination, and herd management to determine control strategies to eradicate JEV in pig herds, reduce sow abortions, assess the risk for human beings living in the vicinity of pig herds and near pig slaughterhouse, and the cost-effectiveness of vaccination. Our results confirm that vector control is the best way to control JEV. Vaccination of pregnant sows reduces abortions as expected. Paradoxically, if the vector control is medium the effectiveness of the vaccination could be compromised. Herd management has a low impact on incidence and abortions, therefore on JE control. Combining sow vaccination and vector control could be an alternative and/or an additional measure to human vaccination to reduce both JE incidence in humans and the economic impact of JE infection on pig breeding. Modélisation Contrôle Encéphalite japonaise Porcs Transmission directe Cambodge Modelling Control Japanese encephalitis Pigs Direct transmission Cambodia
3	Multi-Scale Modelling of Vector-Borne Diseases Mathebula, Dephney 21 September 2018 (has links) PhD (Mathematics) / Department of Mathematics and Applied Mathematics / In this study, we developed multiscale models of vector-borne diseases. In general, the transmission of vector-borne diseases can be considered as falling into two categories, i.e. direct transmission and environmental transmission. Two representative vector-borne diseases, namely; malaria which represents all directly transmitted vector-borne diseases and schistosomiasis which represents all environmentally transmitted vector-borne diseases were studied. Based on existing mathematical modelling science base, we established a new multiscale modelling framework that can be used to evaluate the effectiveness of vector-borne diseases treatment and preventive interventions. The multiscale models consisted of systems of nonlinear ordinary differential equations which were studied for the provision of solutions to the underlying problem of the disease transmission dynamics. Relying on the fact that there is still serious lack of knowledge pertaining to mathematical techniques for the representation and construction of multiscale models of vector-bone diseases, we have developed some grand ideas to placate this gap. The central idea in multiscale modelling is to divide a modelling problem such as a vector-bone disease system into a family of sub-models that exist at different scales and then attempt to study the problem at these scales while simultaneously linking the sub-models across these scales. For malaria, we formulated the multiscale models by integrating four submodels which are: (i) a sub-model for the mosquito-to-human transmission of malaria parasite, (ii) a sub-model for the human-to-mosquito transmission of malaria parasite, (iii) a within-mosquito malaria parasite population dynamics sub-model and (iv) a within-human malaria parasite population dynamics sub-model. For schistosomiasis, we integrated the two subsystems (within-host and between-host sub-models) by identifying the within-host and between-host variables and parameters associated with the environmental dynamics of the pathogen and then designed a feedback of the variables and parameters across the within-host and between-host sub-models. Using a combination of analytical and computational tools we adequately accounted for the influence of the sub-models in the different multiscale models. The multiscale models were then used to evaluate the effectiveness of the control and prevention interventions that operate at different scales of a vector-bone disease system. Although the results obtained in this study are specific to malaria and schistosomiasis, the multiscale modelling frameworks developed are robust enough to be applicable to other vector-borne diseases. / NRF Multiscale models Vector-borne diseases Transmission Direct transmission Environmental transmission Mathematical techniques Malaria Schistosomiasis 616.9362 Insects as carriers of disease Mosquitoes as carriers of disease Communicable diseases -- Transmission Malaria Schistosomiasis Vector control Communicable diseases -- Prevention
4	Cinema ao vivo e experiências audiovisuais em tempo real / - Molina Júnior, Jair Sanches 15 September 2017 (has links) Refletir sobre as experiências com imagens e sons em tempo real é pensar em uma ampla gama de possibilidades e experiências pela humanidade, desde os tempos mais remotos. Pelo fato dessas experiências audiovisuais em tempo real serem numerosas no tempo e no espaço, e já amplamente citada em diferentes estudos, esta apresentação tem por objetivo realizar um recorte mais restrito às experiências audiovisuais em tempo real no campo cinematográfico contemporâneo: uma arte, meio e processo em expansão que culmina na existência de um fenômeno semiótico, realizado principalmente através de modos experimentais com a presença do(s) autor(es) concebendo a experiência audiovisual, conjuntamente ao aparato tecnológico e ao público, todos participantes da criação e exibição da obra audiovisual no mesmo tempo em que ela ocorre, em transmissão direta para a tela de cinema, monitores, telas digitais ou espaços arquitetônicos. Com base em obras audiovisuais realizadas entre 2007 a 2017 desenvolveremos uma reflexão e análise das poéticas e técnicas das experiências audiovisuais em tempo real, de maneira a compreender com um olhar mais atento as possibilidades criativas e contribuir com a reflexão sobre estes formatos do audiovisual contemporâneo, cujos meios e processos estão em contínua expansão de suas fronteiras. Em estética do cinema, esta pesquisa segue em continuidade aos estudos e práticas do cinema experimental e em sua vértice ao cinema expandido. / Reflecting about real-time imagery and sounds experiences is thinking about a wide range of possibilities and experiences for humanity, from the earliest times. Because the real-time audiovisual experiences are numerous in time and space, and already widely quoted in different studies, this presentation aims to make a more restricted cut-off to real-time audiovisual experiences in the contemporary cinematographic field: an art, medium and an expanding process that culminates in the existence of a semiotic phenomenon, performed mainly through experimental modes with the presence of the author(s) directing the audiovisual experience in real-time, together with the technological apparatus, the cast, and the public, all participants in the creation and exhibition of the audiovisual work at the same time as it occurs, in direct transmission to the cinema screen, monitors, digital screens or architectural spaces. Based on audiovisual works carried out between 2007 and 2017 we will develop a reflection and analysis of the poetics and techniques of audiovisual experiences in real-time, in order to understand with a closer look the creatives possibilities in live cinema and contribute with reflection on these forms of the contemporary audiovisual, whose means and processes are in continuous expansion of its borders. In aesthetics of the cinema, this research follows in continuity to the studies and practices of the experimental cinema, and in its vertex to the expanded cinema. aesthetic arte brasileira audiovisual contemporâneo Bienal de São Paulo Bienal of Sao Paulo Brazilian Cinematheque brazylian art cenário Cia. Falbalá Cia. Falbalá Cia. Livre Cia. Livre Ciclo Coletivo Ciclo Coletivo cinema ao vivo cinema expandido cinema experimental cinema on line Cinemateca Brasileira Coletivo Santa Madeira composição composition computador computer contemporary audiovisual digital digital direct transmission Doutores da Alegria Doutores da Alegria editing efect espaço estética expanded cinema experience experiência experimental cinema hardware hardware iluminação Itau Cultural Itaú Cultural Kinoforum Kinoforum language laptop laptop linguagem live cinema mapping montage montagem Museu da Imagem e do Som Museum of Image and Sound Oficina Theater Okra Filmes Okra Filmes. on line cinema participation performance performance poetical projeção projection real-time Santa Madeira Collective scenario Senac Senac Sesc Sesc software software space stage lightning Teat(r)o Oficina teatro Teatro de Narradores Teatro de Narradores technology tecnologia tempo tempo real temporalidade temporality theater time Unesp Unesp Unicamp Unicamp Usp Usp video art videoarte videomapping VJ VJ vjing vjing
5	Performance evaluation and protocol design of fixed-rate and rateless coded relaying networks Nikjah, Reza 06 1900 (has links) The importance of cooperative relaying communication in substituting for, or complementing, multiantenna systems is described, and a brief literature review is presented. Amplify-and-forward (AF) and decode-and-forward (DF) relaying are investigated and compared for a dual-hop relay channel. The optimal strategy, source and relay optimal power allocation, and maximum cooperative gain are determined for the relay channel. It is shown that while DF relaying is preferable to AF relaying for strong source-relay links, AF relaying leads to more gain for strong source-destination or relay-destination links. Superimposed and selection AF relaying are investigated for multirelay, dual-hop relaying. Selection AF relaying is shown to be globally strictly outage suboptimal. A necessary condition for the selection AF outage optimality, and an upper bound on the probability of this optimality are obtained. A near-optimal power allocation scheme is derived for superimposed AF relaying. The maximum instantaneous rates, outage probabilities, and average capacities of multirelay, dual-hop relaying schemes are obtained for superimposed, selection, and orthogonal DF relaying, each with parallel channel cooperation (PCC) or repetition-based cooperation (RC). It is observed that the PCC over RC gain can be as much as 4 dB for the outage probabilities and 8.5 dB for the average capacities. Increasing the number of relays deteriorates the capacity performance of orthogonal relaying, but improves the performances of the other schemes. The application of rateless codes to DF relaying networks is studied by investigating three single-relay protocols, one of which is new, and three novel, low complexity multirelay protocols for dual-hop networks. The maximum rate and minimum energy per bit and per symbol are derived for the single-relay protocols under a peak power and an average power constraint. The long-term average rate and energy per bit, and relay-to-source usage ratio (RSUR), a new performance measure, are evaluated for the single-relay and multirelay protocols. The new single-relay protocol is the most energy efficient single-relay scheme in most cases. All the multirelay protocols exhibit near-optimal rate performances, but are vastly different in the RSUR. Several future research directions for fixed-rate and rateless coded cooperative systems, and frameworks for comparing these systems, are suggested. / Communications acknowledgment signals amplify-and-forward relaying average capacity average power constraint bit error rate cooperative gain cooperative communication decode-and-forward relaying degree of freedom direct transmission distributed space-time coding dual-hop relaying energy efficiency energy per bit energy per symbol feedback communication fixed-rate coded relaying fixed-rate codes fixed-rate coding large SNR approximation maximal ratio combining maximum achievable rates maximum likelihood multiple access channels mutual information nonconcave fractional programming numerical optimization optimal power allocation orthogonal relaying outage optimality outage probability parallel channel coding peak power constraint power allocation schemes power fairness protocol design rateless coded relaying rateless codes rate efficiency rateless coding Rayleigh fading relay-to-source usage ratio relaying networks repetition coding selection relaying single-hop communication superimposed relaying symbol error rate
6	Performance evaluation and protocol design of fixed-rate and rateless coded relaying networks Nikjah, Reza Unknown Date No description available. acknowledgment signals amplify-and-forward relaying average capacity average power constraint bit error rate cooperative gain cooperative communication decode-and-forward relaying degree of freedom direct transmission distributed space-time coding dual-hop relaying energy efficiency energy per bit energy per symbol feedback communication fixed-rate coded relaying fixed-rate codes fixed-rate coding large SNR approximation maximal ratio combining maximum achievable rates maximum likelihood multiple access channels mutual information nonconcave fractional programming numerical optimization optimal power allocation orthogonal relaying outage optimality outage probability parallel channel coding peak power constraint power allocation schemes power fairness protocol design rateless coded relaying rateless codes rate efficiency rateless coding Rayleigh fading relay-to-source usage ratio relaying networks repetition coding selection relaying single-hop communication superimposed relaying symbol error rate
7	Cinema ao vivo e experiências audiovisuais em tempo real / - Jair Sanches Molina Júnior 15 September 2017 (has links) Refletir sobre as experiências com imagens e sons em tempo real é pensar em uma ampla gama de possibilidades e experiências pela humanidade, desde os tempos mais remotos. Pelo fato dessas experiências audiovisuais em tempo real serem numerosas no tempo e no espaço, e já amplamente citada em diferentes estudos, esta apresentação tem por objetivo realizar um recorte mais restrito às experiências audiovisuais em tempo real no campo cinematográfico contemporâneo: uma arte, meio e processo em expansão que culmina na existência de um fenômeno semiótico, realizado principalmente através de modos experimentais com a presença do(s) autor(es) concebendo a experiência audiovisual, conjuntamente ao aparato tecnológico e ao público, todos participantes da criação e exibição da obra audiovisual no mesmo tempo em que ela ocorre, em transmissão direta para a tela de cinema, monitores, telas digitais ou espaços arquitetônicos. Com base em obras audiovisuais realizadas entre 2007 a 2017 desenvolveremos uma reflexão e análise das poéticas e técnicas das experiências audiovisuais em tempo real, de maneira a compreender com um olhar mais atento as possibilidades criativas e contribuir com a reflexão sobre estes formatos do audiovisual contemporâneo, cujos meios e processos estão em contínua expansão de suas fronteiras. Em estética do cinema, esta pesquisa segue em continuidade aos estudos e práticas do cinema experimental e em sua vértice ao cinema expandido. / Reflecting about real-time imagery and sounds experiences is thinking about a wide range of possibilities and experiences for humanity, from the earliest times. Because the real-time audiovisual experiences are numerous in time and space, and already widely quoted in different studies, this presentation aims to make a more restricted cut-off to real-time audiovisual experiences in the contemporary cinematographic field: an art, medium and an expanding process that culminates in the existence of a semiotic phenomenon, performed mainly through experimental modes with the presence of the author(s) directing the audiovisual experience in real-time, together with the technological apparatus, the cast, and the public, all participants in the creation and exhibition of the audiovisual work at the same time as it occurs, in direct transmission to the cinema screen, monitors, digital screens or architectural spaces. Based on audiovisual works carried out between 2007 and 2017 we will develop a reflection and analysis of the poetics and techniques of audiovisual experiences in real-time, in order to understand with a closer look the creatives possibilities in live cinema and contribute with reflection on these forms of the contemporary audiovisual, whose means and processes are in continuous expansion of its borders. In aesthetics of the cinema, this research follows in continuity to the studies and practices of the experimental cinema, and in its vertex to the expanded cinema. arte brasileira audiovisual contemporâneo Bienal de São Paulo cenário Cia. Falbalá Cia. Livre Ciclo Coletivo cinema ao vivo cinema expandido cinema experimental cinema on line Cinemateca Brasileira Coletivo Santa Madeira composição computador digital Doutores da Alegria espaço estética experiência hardware iluminação Itaú Cultural Kinoforum laptop linguagem montagem Museu da Imagem e do Som Okra Filmes. performance projeção Senac Sesc software Teat(r)o Oficina teatro Teatro de Narradores tecnologia tempo tempo real temporalidade Unesp Unicamp Usp videoarte videomapping VJ vjing aesthetic Bienal of Sao Paulo Brazilian Cinematheque brazylian art Cia. Falbalá Cia. Livre Ciclo Coletivo composition computer contemporary audiovisual digital direct transmission Doutores da Alegria editing efect expanded cinema experience experimental cinema hardware Itau Cultural Kinoforum language laptop live cinema mapping montage Museum of Image and Sound Oficina Theater Okra Filmes on line cinema participation performance poetical projection real-time Santa Madeira Collective scenario Senac Sesc software space stage lightning Teatro de Narradores technology temporality theater time Unesp Unicamp Usp video art VJ vjing

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