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The optimal estimation theory of the Wiener-Kalman filter is extended to cover the situation in which the number of memory elements in the estimator is restricted. A method, based on the simultaneous diagonalisation of two symmetric positive definite matrices, is given which allows the weighted least square estimation error to be minimised. A control system design method is developed utilising this estimator, and this allows the dynamic controller in the feedback path to have a low order. A 12-order once-through boiler model is constructed and the performance of controllers of various orders generated by the design method is investigated. Little cost penalty is found even for the one-order controller when compared with the optimal Kalman filter system. Whereas in the Kalman filter all information from past observations is stored, the given method results in an estimate of the state variables which is a weighted sum of the selected information held in the storage elements. For the once-through boiler these weighting coefficients are found to be smooth functions of position, their form illustrating the implicit model reduction properties of the design method. Minimal-order estimators of the Luenberger type also generate low order controllers and the relation between the two design methods is examined. It is concluded that the design method developed in this thesis gives better plant estimates than the Luenberger system and, more fundamentally, allows a lower order control system to be constructed. Finally some possible extensions of the theory are indicated. An immediate application is to multivariable control systems, while the existence of a plant state estimate even in control systems of very low order allows a certain adaptive structure to be considered for systems with time-varying parameters.

Esta pesquisa teve por objetivo avaliar a reabsorção radicular externa em dentes tratados endodonticamente após tratamento ortodôntico, por meio de análise das imagens das radiografias panorâmica final digitalizada, convencional periapical digitalizada e digital direta, como também comparar os métodos radiográficos empregados. Foram selecionados, após uma avaliação de 2.130 documentações ortodônticas 20 dentes de pacientes com documentação ortodôntica completa, boas condições de saúde, faixa etária entre 25 a 50 anos de ambos os sexos e com dentes anteriores (incisivo central ou lateral) tratados endodonticamente antes da realização do tratamento ortodôntico. De cada documentação ortodôntica completa foi selecionada a radiografia panorâmica inicial e final e, posteriormente, foram obtidas duas radiografias periapicais atuais de cada dente, uma pela técnica convencional e outra digital direta. Após a obtenção e identificação das radiografias, as imagens da panorâmica final digitalizada, radiografia periapical convencional digitalizada e digital direta foram analisadas na tela do computador por três especialistas (endodontista, ortodontista e radiologista). Estes avaliaram se a reabsorção radicular externa estava presente ou ausente no dente tratado endodonticamente após tratamento ortodôntico, bem como compararam os métodos empregados verificando sua confiabilidade. Os seguintes parâmetros foram observados: a) lesão periapical, b) espaço pericementário e c) limite do tratamento endodôntico. As observações foram submetidas à análise estatística chegando-se às seguintes conclusões: 1) A maioria dos ortodontistas não utiliza radiografias periapicais para avaliar os dentes tratados endodonticamente antes do tratamento ortodôntico, o que pode comprometer o andamento e o resultado final do tratamento, visto que a reabsorção radicular não apresenta um caráter sintomatológico no seu diagnóstico; 2) Quanto à reabsorção radicular externa, os examinadores apontaram que houve um incremento desta, na maioria do tipo suave e localizada na região apical, e que a radiografia digital direta foi o método radiográfico mais eficiente na determinação deste diagnóstico. / In this research, the assessment of the external root resorption was carried out in endodontically treated teeth after orthodontic treatment, through the analysis of the image of the digital panoramic radiography, the digital periapical conventional and direct digital; as well as the employed methods were comparatively appraised. It was selected, after an evaluation of 2,130 orthodontic records from two centres of orthodontic studies, 20 teeth of patients with complete orthodontic records, good health conditions, age group between 25 and 50 years-old of both sexes and with front teeth (central or lateral incisor) endodontically treated before the accomplishment of the orthodontic treatment. An initial and final panoramic radiography were selected from each orthodontic record, and, later two current radiographies were obtained from each patient, one by conventional technique and the other by direct digital. After the obtaining and identification of the radiographies, the images of the digital panoramic of the digital conventional and of the direct digital were analyzed on the computer screen by three experts (an endodontist, an orthodontist and a radiologist) who evaluated whether the external root resorption was present or absent in the endodontically treated tooth after the orthodontic treatment and comparatively assessed the employed methods, verifying their reliability; they also observed the following parameters: a) periapical lesion, b) pericemental space, and c) limits of the endodontical treatment. The observations were submitted to a statistical analysis, reaching the following conclusions: 1) most of the orthodontists don\'t use periapical radiographies to evaluate endodontically treated teeth. Before the orthodontic treatment, what can compromise its course and its final results, once the root resorption doesn\'t present a symptomatology in its diagnosis; 2) as for the external root resorption, examiners claimed that there was an increment in it, most in the soft type and located in the apical area, and that the evaluation of the effectiveness of the resorption diagnosis, as well as of the other appraised parameters, indicated that the direct digital radiography obtained better outcomes regarding its identification and its classification.

Esta pesquisa in vitro, avaliou comparativamente a acurácia do diagnóstico do método radiográfico digital com o método radiográfico convencional, na detecção de lesões de cárie oclusal em molares decíduos. O material foi composto por 55 dentes posteriores decíduos, que apresentavam pigmentações e pelo menos um sítio suspeito de lesão de cárie oclusal, sem restaurações e superfícies sem selantes. As radiografias digitais foram executadas com o sistema Dixi3 (Planmeca, Helsink, Finland) e as radiografias convencionais com o filme Insight (Kodak Eastman Co., EUA), ambas de modo padronizado, em idênticas condições geométricas. As imagens foram avaliadas individualmente por três radiologistas, em ideais condições de interpretação radiográfica e sem acesso aos recursos de manipulação de imagens do sistema digital. Os achados foram classificados de acordo com o seguinte critério: 0 - ausência de radiolucidez no esmalte, 1- radiolucidez confinada ao esmalte, 2- radiolucidez no esmalte até o limite dentina-esmalte, 3- radiolucidez no esmalte e na metade mais externa da dentina, 4- radiolucidez no esmalte alcançando a metade mais interna da dentina. O padrão ouro foi obtido pelo estudo histológico. Os dados foram analisados através do teste de Freidman (P <= 0,05). Os resultados obtidos com os filmes radiográficos convencionais foram similares aos resultados obtidos com as radiografias digitais diretas e o padrão ouro, porém os resultados obtidos com o sistema radiográfico digital foram significativamente menores que o histológico. Nas condições deste estudo, concluímos que o método de radiografia digital subestimou a extensão das lesões de cárie oclusal em molares decíduos. / This in vitro research, evaluated the accuracy of the direct digital radiographic method compared to the conventional radiographic method in the analysis of the extension of occlusal carious lesions in primary molars. The material was composed by 55 primary molars presenting pigmentation and, at least, one suspect site of occlusal carious lesion, these teeth had neither restoration nor surfaces with sealant. Digital radiographs were obtained with the Dixi3 system (Planmeca, Helsink, Finland) and the conventional radiographs with the Insight film (Kodak Eastman Co., USA), both in standard form and identical geometrical conditions. The images were evaluated individually by three radiologists, in ideal conditions for radiographic interpretation and with no access to the resources of imaging manipulation from the digital system. The results were rated according to the following criteria: 0 - absence of radiolucence in the enamel: 1 - radiolucence confined to the enamel, 2 - radiolucence in the enamel to the limit dentine-enamel, 3 - radiolucence in the enamel and in the half outer part of the dentine, 4 - radiolucence in the enamel reaching to the half inner part of the dentine. The gold standard was obtained by histological study. Data were compared by the Friedman`s test (P <= 0.05). The results obtained with the conventional radiographic films were similar to those obtained with both direct digital radiographs and gold standard; however, the results obtained with the digital radiographic system were significantly lower than those observed in the histological analysis. In the conditions of this study, it was concluded that the direct digital radiographic method significantly underestimate the extension of the occlusal caries lesions in primary molars.

Esta pesquisa teve por objetivo avaliar a reabsorção radicular externa em dentes tratados endodonticamente após tratamento ortodôntico, por meio de análise das imagens das radiografias panorâmica final digitalizada, convencional periapical digitalizada e digital direta, como também comparar os métodos radiográficos empregados. Foram selecionados, após uma avaliação de 2.130 documentações ortodônticas 20 dentes de pacientes com documentação ortodôntica completa, boas condições de saúde, faixa etária entre 25 a 50 anos de ambos os sexos e com dentes anteriores (incisivo central ou lateral) tratados endodonticamente antes da realização do tratamento ortodôntico. De cada documentação ortodôntica completa foi selecionada a radiografia panorâmica inicial e final e, posteriormente, foram obtidas duas radiografias periapicais atuais de cada dente, uma pela técnica convencional e outra digital direta. Após a obtenção e identificação das radiografias, as imagens da panorâmica final digitalizada, radiografia periapical convencional digitalizada e digital direta foram analisadas na tela do computador por três especialistas (endodontista, ortodontista e radiologista). Estes avaliaram se a reabsorção radicular externa estava presente ou ausente no dente tratado endodonticamente após tratamento ortodôntico, bem como compararam os métodos empregados verificando sua confiabilidade. Os seguintes parâmetros foram observados: a) lesão periapical, b) espaço pericementário e c) limite do tratamento endodôntico. As observações foram submetidas à análise estatística chegando-se às seguintes conclusões: 1) A maioria dos ortodontistas não utiliza radiografias periapicais para avaliar os dentes tratados endodonticamente antes do tratamento ortodôntico, o que pode comprometer o andamento e o resultado final do tratamento, visto que a reabsorção radicular não apresenta um caráter sintomatológico no seu diagnóstico; 2) Quanto à reabsorção radicular externa, os examinadores apontaram que houve um incremento desta, na maioria do tipo suave e localizada na região apical, e que a radiografia digital direta foi o método radiográfico mais eficiente na determinação deste diagnóstico. / In this research, the assessment of the external root resorption was carried out in endodontically treated teeth after orthodontic treatment, through the analysis of the image of the digital panoramic radiography, the digital periapical conventional and direct digital; as well as the employed methods were comparatively appraised. It was selected, after an evaluation of 2,130 orthodontic records from two centres of orthodontic studies, 20 teeth of patients with complete orthodontic records, good health conditions, age group between 25 and 50 years-old of both sexes and with front teeth (central or lateral incisor) endodontically treated before the accomplishment of the orthodontic treatment. An initial and final panoramic radiography were selected from each orthodontic record, and, later two current radiographies were obtained from each patient, one by conventional technique and the other by direct digital. After the obtaining and identification of the radiographies, the images of the digital panoramic of the digital conventional and of the direct digital were analyzed on the computer screen by three experts (an endodontist, an orthodontist and a radiologist) who evaluated whether the external root resorption was present or absent in the endodontically treated tooth after the orthodontic treatment and comparatively assessed the employed methods, verifying their reliability; they also observed the following parameters: a) periapical lesion, b) pericemental space, and c) limits of the endodontical treatment. The observations were submitted to a statistical analysis, reaching the following conclusions: 1) most of the orthodontists don\'t use periapical radiographies to evaluate endodontically treated teeth. Before the orthodontic treatment, what can compromise its course and its final results, once the root resorption doesn\'t present a symptomatology in its diagnosis; 2) as for the external root resorption, examiners claimed that there was an increment in it, most in the soft type and located in the apical area, and that the evaluation of the effectiveness of the resorption diagnosis, as well as of the other appraised parameters, indicated that the direct digital radiography obtained better outcomes regarding its identification and its classification.

Esta pesquisa in vitro, avaliou comparativamente a acurácia do diagnóstico do método radiográfico digital com o método radiográfico convencional, na detecção de lesões de cárie oclusal em molares decíduos. O material foi composto por 55 dentes posteriores decíduos, que apresentavam pigmentações e pelo menos um sítio suspeito de lesão de cárie oclusal, sem restaurações e superfícies sem selantes. As radiografias digitais foram executadas com o sistema Dixi3 (Planmeca, Helsink, Finland) e as radiografias convencionais com o filme Insight (Kodak Eastman Co., EUA), ambas de modo padronizado, em idênticas condições geométricas. As imagens foram avaliadas individualmente por três radiologistas, em ideais condições de interpretação radiográfica e sem acesso aos recursos de manipulação de imagens do sistema digital. Os achados foram classificados de acordo com o seguinte critério: 0 - ausência de radiolucidez no esmalte, 1- radiolucidez confinada ao esmalte, 2- radiolucidez no esmalte até o limite dentina-esmalte, 3- radiolucidez no esmalte e na metade mais externa da dentina, 4- radiolucidez no esmalte alcançando a metade mais interna da dentina. O padrão ouro foi obtido pelo estudo histológico. Os dados foram analisados através do teste de Freidman (P <= 0,05). Os resultados obtidos com os filmes radiográficos convencionais foram similares aos resultados obtidos com as radiografias digitais diretas e o padrão ouro, porém os resultados obtidos com o sistema radiográfico digital foram significativamente menores que o histológico. Nas condições deste estudo, concluímos que o método de radiografia digital subestimou a extensão das lesões de cárie oclusal em molares decíduos. / This in vitro research, evaluated the accuracy of the direct digital radiographic method compared to the conventional radiographic method in the analysis of the extension of occlusal carious lesions in primary molars. The material was composed by 55 primary molars presenting pigmentation and, at least, one suspect site of occlusal carious lesion, these teeth had neither restoration nor surfaces with sealant. Digital radiographs were obtained with the Dixi3 system (Planmeca, Helsink, Finland) and the conventional radiographs with the Insight film (Kodak Eastman Co., USA), both in standard form and identical geometrical conditions. The images were evaluated individually by three radiologists, in ideal conditions for radiographic interpretation and with no access to the resources of imaging manipulation from the digital system. The results were rated according to the following criteria: 0 - absence of radiolucence in the enamel: 1 - radiolucence confined to the enamel, 2 - radiolucence in the enamel to the limit dentine-enamel, 3 - radiolucence in the enamel and in the half outer part of the dentine, 4 - radiolucence in the enamel reaching to the half inner part of the dentine. The gold standard was obtained by histological study. Data were compared by the Friedman`s test (P <= 0.05). The results obtained with the conventional radiographic films were similar to those obtained with both direct digital radiographs and gold standard; however, the results obtained with the digital radiographic system were significantly lower than those observed in the histological analysis. In the conditions of this study, it was concluded that the direct digital radiographic method significantly underestimate the extension of the occlusal caries lesions in primary molars.

The aim of this thesis is introduce readers to the basics of digital frequency synthesis and design of direct digital synthesizer with circuit AD9951 by Analog Devices. The device will be controlled from a PC via USB. The device works with internal oscillator, with the ability to connect an external frequency standard of 10 MHz. On input is frequency doubler with transistor. Outpu signal is filtered by low-pass filter and amplified by monolitic amplifier ERA-3+.

This thesis describes the theoretical development, design, and implementation of a novel measurement system, called a Sampling Swept Time Delay Short Pulse (SSTDSP) wireless channel sounder, capable of real time in field performance characterization of high speed fixed wireless links. The SSTDSP sounder has been designed to provide vital performance metrics for fixed point high data rate applications in the 28 GHz LMDS band at a fraction of the cost and complexity of existing wideband channel sounders. The SSTDSP sounder monitors the behavior of the LMDS channel by sampling the impulse response of the channel in real time. This digitized impulse response is used to assemble a power delay profile and render real-time channel performance metrics such as the mean excess delay, RMS delay spread, maximum excess delay for a given multipath threshold, and coherence bandwidth. The SSTDSP sounder is capable of recording these metrics through three modes of operation - continuous channel monitoring, single instant channel snapshot, or data logging. Swept time delay time dilation processing is combined with precise sample and hold gating to reduce the analog to digital converter sampling rate required to digitize the nanosecond short pulses from 2 Gsps to 1 Msps, while retaining the required effective Nyquist sampling rate of 2 Gsps. This dramatically reduces the memory, digital signal processing, and data logging storage requirements as well as the overall cost of the sounder system. The thesis presents the theory behind channel sounding and discusses whether there is a "bounce path" available to LMDS. Several existing channel sounding methods are compared for this application. A number of specific design and performance criteria from each of these methods are synthesized to produce the Sampling Swept Time Delay Short Pulse Sounder architecture. The design and implementation process used to realize the SSTDSP sounder is presented, including a system overview, module details, and algorithm development details. A calibration and measurement test procedure is outlined and system verification results are presented. Current work in progress on the test platform and future improvements to the modular system are outlined, as well as conclusions and future implications of the system. / Master of Science

International Telemetering Conference Proceedings / October 28-31, 1996 / Town and Country Hotel and Convention Center, San Diego, California / In this paper design and development of a PC- Based S- Band Down Converter/ FM Telemetry Receiver are discussed. With the advent of Direct Digital Synthesis (DDS) & Phase Locked Loop (PLL) technology, availability of GaAs & Silicon MMICs, Coaxial Resonator Oscillator (CRO), SAW Oscillator, SAW Filters and Ceramic Filters, realisation of single card PC- Based Down Converter and Telemetry Receiver has become a reality. With the availability of Direct Digital Synthesis and Phase Locked Loop devices having microprocessor bus compatibility, opens up many application in Telemetry and Telecommunications. In this paper design of local oscillator based on hybrid DDS & PLL technique, Coaxial Resonator Oscillator and Front-end are discussed in detail.

International Telemetering Conference Proceedings / October 28-31, 1996 / Town and Country Hotel and Convention Center, San Diego, California / Aerospace Report No. TOR-0059(6110-01)-3, section 1.3.3 outlines the design and performance requirements of SGLS (Space Ground Link Subsystem) uplink services equipment. This modulation system finds application in the U.S. Air Force satellite uplink commanding system. The SGLS signal generator is specified as an FSK (Frequency Shift Keyed)/AM (Amplitude Modulation)/PM (Phase Modulation) sub-carrier modulator. GDP Space Systems has implemented, on a single 6U-VME card, a SGLS signal generator. The modulator accepts data from several possible sources and uses the data to key one of three FSK tone frequencies. This ternary FSK signal is amplitude modulated by a synchronized triangle wave running at one half the data rate. The FSK/AM signal is then used to phase modulate a tunable HF (High-Frequency) sub-carrier. A digital design approach and the availability of integrated circuits with a high level of functionality enabled the realization of a SGLS signal generator on a single VME card. An analog implementation would have required up to three rack-mounted units to generate the same signal. The digital design improve performance, economy and reliability over analog approaches. This paper describes the advantages of a digital FSK/AM/PM modulation method, as well as DDS (Direct Digital Synthesis) and digital phase-lock techniques.