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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Joint Visual and Wireless Tracking System

Nott, Viswajith Karapoondi 01 January 2009 (has links)
Object tracking is an important component in many applications including surveillance, manufacturing, inventory tracking, etc. The most common approach is to combine a surveillance camera with an appearance-based visual tracking algorithm. While this approach can provide high tracking accuracy, the tracker can easily diverge in environments where there are much occlusions. In recent years, wireless tracking systems based on different frequency ranges are becoming more popular. While systems using ultra-wideband frequencies suffer similar problems as visual systems, there are systems that use frequencies as low as in those in the AM band to circumvent the problems of obstacles, and exploit the near-field properties between the electric and magnetic waves to achieve tracking accuracy down to about one meter. In this dissertation, I study the combination of a visual tracker and a low-frequency wireless tracker to improve visual tracking in highly occluded area. The proposed system utilizes two homographies formed between the world coordinates with the image coordinates of the head and the foot of the target person. Using the world coordinate system, the proposed system combines a visual tracker and a wireless tracker in an Extended Kalman Filter framework for joint tracking. Extensive experiments have been conducted using both simulations and real videos to demonstrate the validity of our proposed scheme.
2

Optimal observers and optimal control : improving car efficiency with Kalman et Pontryagin

Sebesta, Kenneth 24 June 2010 (has links) (PDF)
The PhD presents a combined approach to improving individual car efficiency. An optimal observer, the Extended Kalman Filter, is used to create an efficiency model for the car. Particular attention was paid to handling the asynchronous and redundant nature of the measurement data. A low-cost sensor suite developed to measure data is described. This sensor suite was installed on multiple vehicles to good success. It employsan accelerometer, gps, fuel injector timer, and Vss input to measure all the data necessary to reconstruct the car's state. This observer and sensor suite can be used as the base for any study which requires car efficiency maps, allowing research to proceed without manufacturer supplied data. Once the efficiency map is found, it is then curve-fitted in order to reduce model complexity. The simplified model is then used as a basis for optimal control through Pontryagin's Maximum Principle. Real-world test results are given, both for efficiency mapping, and for optimal control. Detailed discussion of the observer and controller is presented, in order to ease understanding and save implementation time
3

Sintonia do filtro de Kalman para medição indireta das variáveis de estado no banho eletrolitico / Tunning of the Filter of Kalman for indirect measurement of the variable of state in the electrolytic bath

Braga, Carlos Augusto Pereira 07 April 2008 (has links)
Made available in DSpace on 2016-08-17T14:52:48Z (GMT). No. of bitstreams: 1 Carlos Augusto Pereira Braga.pdf: 1145854 bytes, checksum: 8898d3084e223e4e9ad52a8aa7363b01 (MD5) Previous issue date: 2008-04-07 / A tunning model for Kalman filter based on QR duality principle is presented to measure the state variables of the electrolytic bath in aluminium production cells. The main goal is to establish a set of filter gains that better represents the percentual of alumina in the bath. The filter bandwidth tunning is performed by increasing or decreasing the filter bandpass from the Q and R variations. The design and analysis of the Q and R covariance matrices are performed to find a pattern of the resistance variations that could be associated with the alumina concentration in the bath. The technical solution encloses on-line evaluation of the Kalman filter in order to prove its capableness of response when used to control real production cells. The Standard Kalman is coded upon a scalar form to reduce the use of computing resources when the filter is processed. The line current and pot voltage are directly read from the hardware interface and then converted in a third variable, the resistance, which is used to infer the alumina concentration in the bath. Moreover, the filter implementation goes in the direction of practical aspects limits of the indirect measurement system implementations, its robustness is appraised by observability, roundo® and modeling errors. / O controle da concentração de alumina no banho de cubas eletroliticas é de vital importância para um rendimento eficiente do processo de produção de aluminio. Este controle tem por objetivo promover, em uma visão macro, um retorno justificável perante ao planejamento global das metas de produção de uma fábrica de aluminio. O desenvolvimento de uma metodologia baseada no ajuste dos ganhos de um filtro tipo Kalman Padrão é o principal enfoque cientifico e tecnológico desta pesquisa. A sintese da metodologia é a implementação do filtro de Kalman Padrão e Escalar em um computador que controla a quantidade de alumina no banho eletrolitico. Considera-se as restrições de software e de hardware na implantação do algoritmo de Kalman no sistema que executa o controle de processo por computador. Desenvolve-se um modelo de sintonia do filtro de Kalman utilizando-se o principio da dualidade das matrizes Q e R. O objetivo é estabelecer um conjunto de ganhos que representem da melhor forma a quantidade de alumina dentro da cuba. Assim, faz-se uma análise considerando-se mudanças nas matrizes Q e R, e apresenta-se os resultados obtidos. Analisa-se a largura de banda do filtro, verificando-se diminuição ou aumento de banda na medida que as matrizes Q e R sofrem alterações em seus elementos. As estratégias de monitoramento são verificadas para diversas situações de operação(dinâmica) da planta, e as variações paramétricas do modelo são levadas em consideração para garantirmos uma operação robusta e estável do filtro. O desempenho do filtro é verificado em paralelo com um sistema de filtragem e de controle historicamente utilizados na estimação do percentual de alumina no banho eletrolitico.
4

Optimal observers and optimal control : improving car efficiency with Kalman et Pontryagin / Observateur et contrôle optimal : améliorer l'efficacité de la conduite automobile avec Kalman et Pontryagin

Sebesta, Kenneth 24 June 2010 (has links)
Ce mémoire de thèse présente une méthode permettant d'améliorer laconduite automobile. Le filtre de Kalman étendu est utilisé pour identifierun modèle de la voiture. Ce filtre est particulièrement étudié afin de prendreen compte la redondance des informations et leur mesure asynchrone.Un ensemble cohérent et bon marché de capteurs - incluant accéléromètres,GPS, temps d'ouverture des injecteurs et vitesse - a été développé et installédans plusieurs véhicules. Ces mesures sont utilisées afin de reconstituer lafonction d'efficacité du moteur. Cette méthodologie peut-être utilisée pourtoute étude requérant la connaissance de cette fonction.La fonction d'efficacité est approchée par une fonction polynomiale etle modèle obtenu est la base d'une optimisation utilisant le principe dumaximum de Pontryagin.Les résultats des tests en condition réelle sont donnés et montrent l'efficicacité de l'observateur et du contrôleur / The PhD presents a combined approach to improving individual car efficiency. An optimal observer, the Extended Kalman Filter, is used to create an efficiency model for the car. Particular attention was paid to handling the asynchronous and redundant nature of the measurement data. A low-cost sensor suite developed to measure data is described. This sensor suite was installed on multiple vehicles to good success. It employsan accelerometer, gps, fuel injector timer, and Vss input to measure all the data necessary to reconstruct the car's state. This observer and sensor suite can be used as the base for any study which requires car efficiency maps, allowing research to proceed without manufacturer supplied data. Once the efficiency map is found, it is then curve-fitted in order to reduce model complexity. The simplified model is then used as a basis for optimal control through Pontryagin's Maximum Principle. Real-world test results are given, both for efficiency mapping, and for optimal control. Detailed discussion of the observer and controller is presented, in order to ease understanding and save implementation time

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