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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.
221

Helping a Young Child Connect Fact Family Addition and Subtraction using Tools

Kurz, Terri L., Yanik, H. Bahadir, Garcia, Jorge 04 May 2012 (has links) (PDF)
In order to help children become effective at addition and subtraction, it is important to provide them with an opportunity to investigate and discover the interconnectedness of the two operations. Fact families are one method teachers use to try and help children develop and understand how the operations relate to one another. This paper documents a strategy that was used with a seven year old boy to help him connect addition to subtraction. The strategy incorporated flash card tools to help him create logical problems to discover the mathematical relationship of fact families. With just a few trials, the child was able to create and explain problems that demonstrated the interconnectedness of fact families through addition and subtraction. The model was successful in helping the child advance his understanding. Additionally, it can be extended to more complex addition and subtraction problems as well as multiplication and division fact families.
222

Volume imaging of the abdomen : three-dimensional visualisation of tubular structures in the body with CT and MRI /

Persson, Anders, January 2005 (has links) (PDF)
Diss. Linköping : Linköpings universitet, 2005.
223

[en] SPEECH RECOGNITION IN NOISE ENVIRONMENT / [es] RECONOCIMIENTO DE VOZ EN PRESCENCIA DE RUIDO / [pt] RECONHECIMENTO DE VOZ EM PRESENÇA DE RUÍDO

DEBORA ANDREA DE OLIVEIRA SANTOS 02 October 2001 (has links)
[pt] Este trabalho apresenta um estudo comparativo de três técnicas de melhoria das taxas de reconhecimento de voz em ambiente adverso, a saber: Normalização da Média Cepestral (CMN), Subtração Espectral e Regressão Linear no Sentido da Máxima Verossimilhança (MLLR), aplicadas isoladamente e em concomitância, duas a duas. Os testes são realizados usando um sistema simples: reconhecimento de palavras isoladas (dígitos de zero a nove, e meia), modo dependente do locutor, modelos ocultos de Markov do tipo contínuo, e vetores de atributos com doze coeficientes cepestrais derivados da análise de predição linear. São adotados três tipos de ruído (gaussiano branco, falatório e de fábrica) em nove razões sinal-ruído diferentes. Os resultados experimentais demonstram que o emprego isolado das técnicas de reconhecimento robusto é, em geral, vantajoso, pois nas diversas razões sinal-ruído para as quais os testes são efetuados, quando as taxas de reconhecimento não sofrem um acréscimo, mantém-se as mesmas obtidas quando não se aplica nenhum método de aumento da robustez. Analisando-se comparativamente as implementações isoladas e simultânea das técnicas, constata-se que a simultânea nem sempre é atraente, dependendo da dupla empregada. Apresentam-se, ainda, os resultados decorrentes do uso de modelos ruidosos, observando-se que, embora sejam inegavelmente melhores, sua utilização é inviável na prática. Das técnicas implementadas, a que representa resultados mais próximos ao emprego de modelos ruidosos é a MLLR, seguida pela CMN, e por último pela Subtração Espectral. Estas últimas, embora percam em desempenho para a primeira, apresentam como vantagem a simplicidade e a generalidade. No que concerne as técnicas usadas concomitantemente, a dupla Subtração Espectral e MLLR é a considerada de melhor performance, pois mostra-se conveniente em relação ao emprego isolado de ambos os métodos, o que nem sempre ocorre com o uso de outras combinações das técnicas individuais. / [en] This work presents a comparative study of three techniques for improving the speech recognition rates in adverse environment, namely: Cepstral Mean Normalization (CMN), Spectral Subtraction and Maximum Likelihood Linear Regression (MLLR). They are implemented in two ways: separately and in pairs. The tests are carried out on a simple system: recognition of isolated words (digits from zero to nine, and the word half), speaker-dependent mode, continuous hidden Markov models, and speech feature vectors with twelve cepstral coefficients derived from linear predictive analysis. Three types of noise are considered (the white one, voice babble and from factory) at nine different signal-to-noise ratios. Experimental result demonstrate that it is worth using separately the techniques of robust recognition. This is because for all signal-to-noise conditions when the recognition accuracy is not improved it is the same one obtained when no method for increasing the robustness is applied. Analyzing comparatively the isolated and simultaneous applications of the techniques, it is verified that the later is not always more attractive than the former one. This depends on the pair of techniques. The use of noisy models is also considered. Although it presents better results, it is not feasible to implement in pratical situations. Among the implemented techniques, MLLR presents closer results to the ones obtaneid with noisy models, followed by CMN, and, at last, by Spectral Subtraction. Although the two later ones are beaten by the first, in terms of recognition accuracy, their advantages are the simplicity and the generality. The use of simultaneous techniques reveals that the pair Spectral Subtraction and MLLR is the one with the best performance because it is superior in comparison with the individual use of both methods. This does not happen with other combination of techniques. / [es] Este trabajo presenta un estudio comparativo de tres técnicas de mejoría de las tasas de reconocimiento de voz en ambiente adverso, a saber: Normalización de la Media Cepextral (CMN), Substracción Espectral y Regresión Lineal en el Sentido de la Máxima Verosimilitud (MLLR), aplicadas separada y conjuntamente, dos a dos. Las pruebas son realizados usando un sistema simple: reconocimiento de palabras aisladas (dígitos de cero al nueve, y media), de modo dependiente del locutor, modelos ocultos de Markov de tipo contínuo, y vectores de atributos con doce coeficientes cepextrales derivados del análisis de predicción lineal. Se adoptan tres tipos de ruido (gausiano blanco, parlatorio y de fábrica) en nueve razones señal- ruido diferentes. Los resultados experimentales demuestran que el empleo aislado de las técnicas de reconocimiento robusto es, en general, ventajoso, pues en las diversas relaciones señal ruido para las cuales las pruebas son efetuadas, cuando la tasa de reconocimiento no aumenta, manteniendo las mismas tasas cuando no se aplica ningún método de aumento de robustez. Analizando comparativamente las implementaciones aisladas y simultáneas de las técnicas, se constata que no siempre la simultánea resulta atractiva, dependiendo de la dupla utilizada. Se presentan además los resultados al utilizar modelos ruidosos, observando que, aunque resultan mejores, su utilización em la práctica resulta inviable. De las técnicas implementadas, la que presenta resultados más próximos al empleo de modelos ruidosos es la MLLR, seguida por la CMN, y por último por la Substracción Espectral. Estas últimas, aunque tienen desempeño peor que la primera, tienen como ventaja la simplicidad y la generalidad. En lo que se refiere a las técnicas usadas concomitantemente, la dupla Substracción Espectral y MLLR es la de mejor performance, pues se muestra conveniente en relación al empleo aislado de ambos métodos, lo que no siempre ocurre con el uso de otras combinaciones de las técnicas individuales.
224

Pokročilé algoritmy fúze 3D medicínských dat pro specifické lékařské problémy / Advanced Algorithms for 3D Medical Image Data Fusion in Specific Medical Problems

Malínský, Miloš January 2013 (has links)
Fúze obrazu je dnes jednou z nejběžnějších avšak stále velmi diskutovanou oblastí v lékařském zobrazování a hraje důležitou roli ve všech oblastech lékařské péče jako je diagnóza, léčba a chirurgie. V této dizertační práci jsou představeny tři projekty, které jsou velmi úzce spojeny s oblastí fúze medicínských dat. První projekt pojednává o 3D CT subtrakční angiografii dolních končetin. V práci je využito kombinace kontrastních a nekontrastních dat pro získání kompletního cévního stromu. Druhý projekt se zabývá fúzí DTI a T1 váhovaných MRI dat mozku. Cílem tohoto projektu je zkombinovat stukturální a funkční informace, které umožňují zlepšit znalosti konektivity v mozkové tkáni. Třetí projekt se zabývá metastázemi v CT časových datech páteře. Tento projekt je zaměřen na studium vývoje metastáz uvnitř obratlů ve fúzované časové řadě snímků. Tato dizertační práce představuje novou metodologii pro klasifikaci těchto metastáz. Všechny projekty zmíněné v této dizertační práci byly řešeny v rámci pracovní skupiny zabývající se analýzou lékařských dat, kterou vedl pan Prof. Jiří Jan. Tato dizertační práce obsahuje registrační část prvního a klasifikační část třetího projektu. Druhý projekt je představen kompletně. Další část prvního a třetího projektu, obsahující specifické předzpracování dat, jsou obsaženy v disertační práci mého kolegy Ing. Romana Petera.
225

Enquête comparatiste sur la mise en œuvre d’une ingénierie didactique pour l’enseignement de la soustraction au premier cycle du primaire dans plusieurs systèmes didactiques : études de cas en Suisse et en France / Comparative inquiry on the implementation of an experimental design related to the teaching of subtraction in primary school (7-8 years old) in various didactical systems : case studies in Switzerland and France

Couderette, Michèle 12 February 2018 (has links)
Cette thèse, au croisement de la didactique comparée et de la didactique des mathématiques, porte sur la mise en œuvre dans des classes ordinaires actuelles d’une ingénierie didactique broussaldienne élaborée dans les années 80. L’ingénierie concerne l’introduction de la soustraction à l’École primaire (7-8 ans). La recherche s’appuie sur des études de cas. Elle analyse, selon une approche comparative, le fonctionnement de trois systèmes didactiques contrastés par 1) leur appartenance à des systèmes éducatifs différents : l’un en France, l’autre en Suisse ; 2) l’expérience des enseignantes : chevronnées versus en début de carrière. L’enquête, qualitative, porte sur 52 séances de mathématiques et rend compte, a partir du modèle théorique de l’Action Conjointe en Didactique (ACD), de la co-construction in situ du savoir relatif à la soustraction via une analyse ascendante de la transposition didactique. L’articulation de différentes échelles d’analyse (mésodidactique et microdidactique documentant l’interprétation macrodidactique) met en évidence l’influence combinée des préconstruits institutionnels et de l’épistémologie pratique des professeurs sur les mises en œuvre observées. En cela, les résultats rejoignent ceux d’autres travaux comparatistes montrant un entrelacement de ces deux déterminants comme dimension générique présidant à l’interprétation de phénomènes didactiques. Par ailleurs, la recherche permet de mettre en évidence deux moments cruciaux dans l’architecture de l’ingénierie didactique. Ces deux moments mettent exergue la nécessité d’une compréhension fine par les enseignants des logiques épistémiques des ressources didactiques qu’ils utilisent dans leur classe. / This doctoral thesis, located at the crossing of comparative didactics and mathematic didactics aims at characterizing the implementation of an instructional design built in the 1980s in current regular classes. The instructional design concerns the introduction of subtraction in primary school (7-8 years old). The research is rooted in case studies, It carries out a comparative analysis of the functioning of three didactical systems which are contrasted by 1) their educational systems affiliation: Suiss and French; 2) the difference in teachers’ experiences in teaching. The qualitative inquiry focuses on 52 lessons in mathematics. It is conducted against the background of the theoretical framework of Joint Action in Didactics (JAD) and it accounts for the in situ co-construction of the knowledge related to subtraction through a bottom up analysis of the didactic transposition. The articulation of various analytic scales (mesodidactic and microdidactic that document the macrodidactic interpretation) underlines the combined influence of curriculum orientations and teacher’s practical epistemology on observed implementations. In that, the findings converge to other comparatist works showing the interweaving of these two determinants as a generic dimension affecting the interpretation of didactic phenomena. In addition, the research highlights two crucial stages in the organization of this instructional design, that underline the need for teacher’s clear understanding of the epistemic logic of any didactical resources used in their class.
226

Alterações de difusão e perfusão cerebral por RM em angioplastia carotídea com \"stent\" sob proteção cerebral por filtros / Changes in diffusion and perfusion weighted magnetic resonance imaging in carotid angioplasty with stenting under cerebral protection by filters

Antenor Tavares de Sá Júnior 09 October 2009 (has links)
INTRODUÇÃO: A angioplastia carotídea com stent (ACS) sob proteção cerebral é opção terapêutica em pacientes com estenose carotídea. Existe o risco de embolia apesar da utilização do filtro e as modificações na perfusão cerebral após tratamento da estenose carotídea não são claras. O propósito deste estudo é avaliar, após ACS sob proteção cerebral por filtros, modificações nas seqüências de RM de difusão (DWI) e perfusão (PWI), correlacionando-as com os aspectos técnicos da ACS, com as características da estenose e com dados demográficos dos pacientes. MÉTODO: Trinta e seis pacientes portadores de estenose carotídea com idade média de 72,08 anos foram submetidos a exame de RM um dia antes e até 72 horas após a ACS com filtro de proteção. Todos os pacientes eram assintomáticos após a ACS. Áreas de restrição na DWI após a ACS foram correlacionadas com aspectos demográficos, com aspectos da técnica de angioplastia e com a presença de infartos prévios por RM. Os parâmetros CBV volume sanguíneo cerebral, MTT tempo de trânsito médio e TTP tempo para o pico são empregados para análise por PWI. RESULTADOS: Na DWI, 18 de 36 (50,00%) pacientes apresentaram novos focos (NF) de restrição na DWI após ACS. Todos os NF foram clinicamente silenciosos (100%). Estes NF eram localizados em território cerebral nutrido pela artéria carótida submetida à ACS em 77,19% e menores que 10 mm em 91,53%. Os NF em território cerebral não irrigado pela artéria carótida submetida à angioplastia correspondiam a 22,81% destes. A presença de infartos cerebrais prévios na RM foi o único fator com influência no aparecimento de NF (p=0,037). Fatores demográficos e aspectos relacionados com a técnica de angioplastia não tiveram importância na gênese dos NF. Na PWI foi observada melhora nos parâmetros temporais TTP (p<0,001) e MTT (p=0,019) quando comparados de forma normalizada em relação ao território contralateral. CONCLUSÃO: Os novos focos de restrição na DWI após ACS (NF) foram mais comuns no território ipsilateral (77,19%), no entanto houve NF no território contralateral à ACS (22,81%), possivelmente, associados ao cateterismo diagnóstico. Os NF, na sua maioria, são de pequeno diâmetro (<10 mm em 91,53%). Melhora precoce na PWI, observada nos dados normalizados, foi demonstrada nos parâmetros temporais (TTP e MTT). / INTRODUCTION: Carotid angioplasty with stent (CAS) under cerebral protection is a therapeutic option in patients with carotid stenosis. There is a risk of embolism even with a filter, and changes in cerebral perfusion after treatment are not clearly understood. The purpose of this study was to evaluate changes in diffusion- (DWI) and perfusion- (PWI) weighted magnetic resonance imaging (MRI) sequences correlating them with the technical aspects of CAS, stenosis characteristics and patient demographic data. METHODS: Thirty-six carotid stenosis patients with an mean age of 72.08 years were submitted to MRI exam one day before and up to 72 hours after CAS with filter protection. All patients were asymptomatic after CAS. Areas of restriction on DWI were correlated to demographic aspects, technique of angioplasty as well the presence of previous stroke by MRI. The parameters, CBV - cerebral blood volume; MTT - mean transit time, and TTP- time to peak, are used for PWI analysis. RESULTS: Eighteen of the 36 patients (50.00%) presented new focus (NF) of restriction by DWI after CAS. All new focus were clinically silent. The NF were located in the cerebral area fed by the carotid artery submitted to CAS in 77.19% and smaller than 10mm in 91.53%. NF in cerebral area not irrigated by carotid artery submitted by angioplasty correspond to 22,81 %. The presence of previous ischemic lesion on MRI was the only factor which influenced the appearance of NF (p=0.037). Demographic factors and aspects related to angioplasty technique had no importance on NF genesis. Improvement in PWI timing parameters - TTP (p<0.001) and MTT (p=0.019) were observed in relation to the contralateral territory (normalized data). CONCLUSION: The restriction NF in the DWI after CAS are more common in the ipsilateral territory (77.19%), however there were some NF in the contralateral territory to the CAS (22.81%), possibly associated with diagnostic catheterization. Most of the NF were small in diameter (<10mm in 91.53%). Short-term improvement in PWI were demonstrated by normalized timing parameters (TTP and MTT).
227

Reconhecimento de atividades suspeitas em ambiente externo via análise de vídeo infravermelho

Fernandes, Henrique Coelho 26 October 2011 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Surveillance has become, in the last years, something ubiquity in our society. Every day it is more notorious the presence of intelligent systems for surveillance in our everyday life. This is due to technological advances achieved in recent decades (storage and processing speed increasing, miniaturization of devices like biometric detectors and video cameras) as the constant feeling of insecurity experienced in several countries. Following the dark days of 9/11, security and surveillance became paramount. This work aims the study of techniques for the development of a surveillance system of an outdoor parking lot based on a stationary camera. Considering that in an outdoor parking lot it is very important that the surveillance is made both day and night, in this work we use an infrared camera to record images. An infrared camera allows to see objects of interest in the scene even at night. The images used for the experiments in this work were recorded by the student in Laval University campus (Canada) during an internship he held in the "Canada Research Chair in Multipolar Infrared Vision". A surveillance system based on video cameras is usually composed of three parts: (i) motion detection, (ii) tracking and (iii)event management. In this work, we use a dynamic background subtraction technique to detect motion (motion segmentation). This technique adapts to abrupt changes on the scene's illumination making the technique robust to this changes. Besides, we use ow analysis to restrict the segmentation process only to regions where we have motion in the scene. The object tracking technique used is based on a two phase cycle: prediction and correction. The events of interest which occur in the monitored area are modeled explicitly and then recognized and interpreted. The main goal of this project is to recognize suspicious events. Experimental results show that such techniques are suitable for a surveillance system for an outdoor parking lot based on a infrared stationary camera. / Vigilância se tornou, nos últimos anos, algo ubíquo em nossa sociedade. Cada dia que passa é mais notória a presença de sistemas inteligentes de vigilância em nosso dia-a-dia. Isso se deve tanto aos avanços tecnológicos alcançados nas últimas décadas (aumento da capacidade de processamento e armazenamento, miniaturização de dispositivos como detectores biométricos e câmeras de vídeo) como a constante sensação de insegurança vivida em vários países. Após os dias sombrios de 11/09, segurança e vigilância se tornaram algo primordial. Este trabalho visa o estudo de técnicas para o desenvolvimento de um sistema de vigilância para um estacionamento externo baseado em uma câmera estacionária. Tendo em vista que em um estacionamento externo é de suma importância que a vigilância seja feita tanto de dia quanto de noite, neste trabalho utilizamos uma câmera que captura imagens infravermelhas. Uma câmera infravermelha permite que enxerguemos objetos de interesse na cena até mesmo a noite. As imagens usadas nos experimentos realizados neste trabalho foram colhidas no campus da Universidade de Laval (Canadá) durante um estágio realizado no Canada Research Chair in Multipolar Infrared Vision. Um sistema de vigilância baseado em câmeras de vídeo geralmente possui três partes principais: (i) detecção de movimento, (ii) monitoramento e (iii) gerenciamento de eventos. Neste trabalho, utilizamos uma dinâmica técnica de subtração de plano de fundo para realizar a detecção de movimento (segmentação de movimento). Esta técnica se adapta às mudanças bruscas de iluminação na cena tornando o método de segmentação robusto a estas mudanças. Além disso, utilizamos análise de uxo de movimento para restringir a segmentação somente às regiões onde existem algum movimento na cena. A técnica de monitoramento de objetos em movimento usada neste trabalho é baseada em um ciclo de dois estágios: previsão e correção. Os eventos de interesse que ocorrem na área monitorada são modelados de forma explícita sendo então reconhecidos e interpretados. O foco principal deste trabalho é o reconhecimento de eventos suspeitos. Resultados experimentais obtidos mostram que tais técnicas são adequadas para um sistema de vigilância de um estacionamento externo baseado em uma câmera estacionária infravermelha. / Mestre em Ciência da Computação
228

Estimativa da dose no paciente e na equipe médica em procedimentos de quimioembolização hepática

GARZÓN, William Jaramillo 15 August 2016 (has links)
Submitted by Irene Nascimento (irene.kessia@ufpe.br) on 2017-03-21T19:51:42Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) TESE FINAL versão digital.pdf: 2839254 bytes, checksum: 962b7ff83b975bcd276b612274de7368 (MD5) / Made available in DSpace on 2017-03-21T19:51:42Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) TESE FINAL versão digital.pdf: 2839254 bytes, checksum: 962b7ff83b975bcd276b612274de7368 (MD5) Previous issue date: 2016-08-15 / Facepe / Dentre os diversos procedimentos intervencionistas com fins terapêuticos, a quimioembolização hepática tem se destacado por ser de alta complexidade e resultar em altas doses de radiação aos pacientes e à equipe médica. Em alguns casos, o paciente requer várias sessões para tratar a mesma lesão, o que aumenta a probabilidade de ocorrência de lesões na pele e/ou efeitos estocásticos. Embora seja uma técnica altamente utilizada no Brasil, a quimioembolização não tem sido alvo de estudos dosimétricos. Este estudo apresenta os resultados da avaliação dosimétrica realizada na equipe médica e pacientes durante 109 procedimentos de quimioembolização hepática, realizados em seis serviços de hemodinâmica na cidade de Recife, Pernambuco. Os procedimentos foram realizados utilizando equipamentos de angiografia digital de diferentes fabricantes e tecnologias. A dosimetria dos pacientes foi caracterizada através das estimativas da máxima dose na pele (MDP), do produto kerma ar-área (PKA) e do kerma ar de referência (Ka,r). A MDP foi estimada a partir da utilização de filmes radiocrômicos do tipo Gafchromic XR RV3. Para avaliar o risco de efeitos estocásticos, foi estimada a dose absorvida em órgãos a partir de simulações Monte Carlo utilizando fantomas antropomórficos femininos e masculinos da serie FASH e MASH. Os resultados da dosimetria com filme radiocrômico mostraram valores da MDP variando de 180 a 5650 mGy; sendo que 40% dos pacientes apresentaram valores de dose na entrada da pele que ultrapassaram o limiar de dose para ocorrência de eritema transitório, que é de 2 Gy. O estudo das correlações entre a MDP, PKA e Ka,r mostrou que o Ka,r pode ser utilizado para avaliar a possibilidade de ocorrência de reações tissulares na pele dos pacientes submetidos a procedimentos de quimioembolização. Os resultados das simulações mostraram que alguns órgãos internos dos pacientes podem receber doses entre 500 mGy e 1 Gy. A dosimetria ocupacional foi realizada utilizando dosímetros termoluminescentes e dispositivos eletrônicos pessoais distribuídos em varias regiões do corpo dos profissionais. Os resultados mostraram que, com apenas uma quimioembolização por semana, o médico principal pode ultrapassar o limite anual de 20 mSv para o cristalino quando não são utilizados dispositivos de radioproteção como óculos ou telas de acrílico plumbíferos. O valor mais alto de equivalente de dose pessoal Hp(d) por procedimento medido no corpo do médico principal foi 5135,3 μSv no pé esquerdo. A ausência da cortina plumbífera durante a realização dos procedimentos é uma explicação para os valores altos registrados. Os valores médios de dose efetiva por procedimento para o médico principal, médico auxiliar e anestesista numa das instituições acompanhadas foram: 13 μSv, 6,1 μSv e 13,7 μSv, respectivamente. Estes resultados mostram que os níveis de exposição recebidos pelo anestesista em procedimentos de quimioembolização podem ser superiores aos do médico principal. Os resultados da dosimetria ocupacional com dosimetros eletrônicos mostraram que estes dispositivos podem ser utilizados de forma complementar na estimativa da dose ocupacional no cristalino em procedimentos de quimioembolização hepática. Nas seis instituições avaliadas observou-se uma alta variabilidade nos valores de dose no paciente e equipe médica, devido, principalmente, ao desempenho dos equipamentos, complexidade dos procedimentos, características físicas dos pacientes e experiência dos médicos. / Among interventional procedures, hepatic chemoembolization has been recognized as a complex procedure where high radiation doses to patients and medical staff are delivered. In some cases the patient has to endure several sessions to treat the same lesion, which increases even more the probability of skin injuries or stochastic effects. In Brazil, chemoembolization is widely used; however few dosimetric studies have been done so far. This study presents dosimetric results for medical staff and patients based on 109 hepatic chemoembolization procedures conducted in six hemodynamic departments in Recife, Pernambuco. The procedures were performed using digital angiography equipments from different manufacturers, using different technologies. Patient dosimetry comprised the measurement of the maximum skin dose (MSD), air kerma-area product (PKA) and reference air kerma (Ka,r). The MSD was measured using radiochromic films of type Gafchromic XR RV3. To assess the risk of stochastic effects, organ absorbed doses were calculated by Monte Carlo simulations using female and male anthropometric phantoms of the FASH and MASH series. MSDs between 180 and 5650 mGy were found based on the radiochromic film measurements. 40% of the patients monitored with radiochromic films received MSDs above the 2 Gy threshold for transient skin erythema. The findings of this study showed that the Ka,r can be used for risk estimates of tissue reactions in patients undergoing chemoembolization procedures. The Monte Carlo simulations showed that patients may receive organ doses between 500 mGy and 1 Gy. Occupational dosimetry was performed using thermoluminescent dosimeters and personal electronic devices distributed over various regions of the physician’s body. The results showed that the main operator could reach the annual limit of 20 mSv for the equivalent dose in the lens of the eyes with just one procedure per week if the radiation shields such as the ceiling suspended screen and goggles are not used. The highest values of personal dose equivalent Hp(d), measured in the body of the main operator was 5135.3 μSv in the left foot. Lack of table curtains explains the registered high values. Mean effective doses for the main operator, the auxiliary physician and the anesthesiologist in one of the institutions were 13 μSv, 6.1 μSv e 13.7 μSv, respectively. These results show that occupational doses received by the anesthesiologist in chemoembolization procedures may be higher than those received by the main operator. The results of the occupational dosimetry using electronic dosimeters showed that these devices can be used in a complementary way to estimate the occupational eye lens doses in hepatic chemoembolization procedures. High variability of radiation doses to patients and medical staff was observed among the six medical institutions, mainly because of the performance of X-ray equipments, complexity of the procedures, physical characteristics of the patients and the physician´s experience
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Evaluation intrakranieller In-Stent-Restenosen nach Stenting mit Hilfe digitaler Subtraktionsangiographie, Flachdetektor-CT und Multidetekor-CT / Evaluation of intracranial in-stent restenoses after stenting by digital subtraction angiography, flat-detector CT and multidetector CT

Amelung, Nadine 10 October 2017 (has links)
No description available.
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Suivi visuel d'objets dans un réseau de caméras intelligentes : application au systèmes de manutention automatisés / Multiple object tracking on smart cameras : application to automated handling systems

Benamara, Mohamed Adel 19 December 2018 (has links)
L’intralogistique (ou logistique interne) s’intéresse au traitement et à l’optimisation des flux physiques au sein des entrepôts, centres de distribution et usines. Les systèmes de manutention automatisés sont au cœur de la logistique interne de plusieurs industries comme le commerce en ligne, la messagerie postale, la grande distribution, l’industrie manufacturière, le transport aéroportuaire, etc. Ces équipements composés de lignes de convoyage haute cadence permettent un transport sûr et fiable d’un volume considérable de biens et de marchandises tout en réduisant les coûts.L’automatisation de l’acheminement des flux physiques par les systèmes de manutention repose sur l’identification et le suivi en temps réel des charges transportées. Dans cette thèse, nous explorons une solution de suivi qui emploie un réseau de caméras intelligentes à champs recouvrants. L’objectif final étant de fournir l’information de suivi sur les charges transportées pour le pilotage d’un système de manutention.Le suivi d’objets est un problème fondamental de la vision par ordinateur qui a de nombreuses applications comme la vidéosurveillance, la robotique, les voitures autonomes, etc. Nous avons intégré plusieurs briques de base issues de la vidéosurveillance et traditionnellement appliquées aux scènes de surveillance automobile ou de surveillance des activités humaines pour constituer une chaine de suivi de référence. Cette chaine d’analyse vidéo étalon nous a permis de caractériser des hypothèses propres au convoyage d’objet. Nous proposons dans cette thèse d’incorporer cette connaissance métier dans la chaine de suivi pour en améliorer les performances. Nous avons, notamment pris en compte, dans l’étape de segmentation des images, le fait que les objets doivent pouvoir s’arrêter sans pour autant être intégrés aux modèles d’arrière-plan. Nous avons également exploité la régularité des trajectoires des objets convoyés dans les installations, permettant d’améliorer les modèles prédictifs de la position et de la vitesse des objets, dans les étapes de suivi. Enfin, nous avons intégré des contraintes de stricte monotonie dans l’ordre des colis sur le convoyeur, contraintes qui n’existent pas dans les scènes généralistes, pour ré-identifier les objets dans les situations où ils sont proches des eux les autres.Nous nous sommes par ailleurs attelés à un problème pratique d’optimisation des performances sur l’architecture multi-cœurs couplée aux caméras intelligentes. Dans ce cadre, nous avons a mis en place un apprentissage dynamique de la zone de l’image contenant le convoyeur. Cette zone d’intérêt nous a permis de limiter la mise à jour du modèle de fond à cette seule zone. Nous avons, par la suite, proposé une stratégie de parallélisation qui partitionne de manière adaptative cette région d’intérêt de l’image, afin d’équilibrer au mieux la charge de travail entre les différents cœurs de l’architecture des caméras intelligentes.Nous avons également traité la problématique du suivi sur plusieurs caméras. Nous avons proposé une approche basée sur un système de composition d’évènements. Cette approche nous a permis de fusionner les données de suivi local pour former les trajectoires globales des colis, tout en intégrant des informations issues du processus métier, par exemple la saisie de l’information de destination par des opérateurs sur un terminal avant la dépose des colis. Nous avons validé cette approche sur un système de manutention mis en place dans un centre de tri postal de grande envergure. Le réseau de caméras déployé est composé de 32 caméras qui assurent le suivi de plus de 400.000 colis/jour sur des lignes de dépose. Le taux d’erreur du suivi obtenu est inférieur à 1 colis sur 1000 (0,1%). / Intralogistics (or internal logistics) focuses on the management and optimization of internal production and distribution processes within warehouses, distribution centers, and factories. Automated handling systems play a crucial role in the internal logistics of several industries such as e-commerce, postal messaging, retail, manufacturing, airport transport, etc. These systems are composed by multiple high-speed conveyor lines that provide safe and reliable transportation of a large volume of goods and merchandise while reducing costs.The automation of the conveying process relies on the identification and the real-time tracking of the transported loads. In this thesis, we designed a tracking solution that employs a network of smart cameras with an overlapping field of view. The goal is to provide tracking information to control an automated handling system.Multiple object tracking is a fundamental problem of computer vision that has many applications such as video surveillance, robotics, autonomous cars, etc. We integrated several building blocks traditionally applied to traffic surveillance or human activities monitoring to constitute a tracking pipeline. We used this baseline tracking pipeline to characterize contextual scene information proper to the conveying scenario. We integrated this contextual information to the tracking pipeline to enhance the performance. In particular, we took into account the state of moving objects that become stationary in the background subtraction step to prevent their absorption to the background model. We have also exploited the regularity of objects trajectory to enhance the motion model associated with the tracked objects. Finally, we integrated the precedence ordering constraint among the conveyed object to reidentify them when they are close to each other.We have also tackled practical problems related to the optimization the execution of the proposed tracking problem in the multi-core architectures of smart cameras. In particular, we proposed a dynamic learning process that extracts the region of the image that corresponds to the conveyor lines. We reduced the number of the processed pixel by restricting the processing to this region of interest. We also proposed a parallelization strategy that adaptively partitions this region of interest of the image, in order to balance the workload between the different cores of the smart cameras.Finally, we proposed a multiple cameras tracking algorithms based on event composition. This approach fuses the local tracking generated by the smart cameras to form global object trajectories and information from third party systems such as the destination of the object entered by operators on a terminal. We validated the proposed approach for the control of a sorting system deployed in a postal distribution warehouse. A network of cameras composed of 32 cameras tracks more than 400.000 parcel/day in injections lines. The tracking error rate is less than 1 parcel in a 1000 (0.1%).

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