Atualmente, sabe-se que grande parte dos acidentes graves ocorridos envolvendo uma diversidade de sistemas como plataformas de petróleo, aeronaves ou plantas de processos industriais, poderiam ser evitados caso possuíssem dispositivos de controle projetados especificamente para manter a segurança durante a ocorrência de falhas no funcionamento dos mesmos. Por outro lado, observam-se complicações em realizar o controle de sistemas remotos em que é possível não haver garantia de monitoração em tempo real, como o caso de sondas espaciais ou robôs de exploração. Neste contexto, podem-se encontrar ambas as dificuldades no controle do funcionamento de um Dispositivo de Assistência Ventricular (DAV) que desempenha a função de auxiliar o bombeamento de sangue para o sistema circulatório de um paciente com insuficiência cardíaca. Este tipo de dispositivo, quando usado para terapia de destino, deve apresentar um elevado nível de segurança, pois, caso haja falha, o risco de morte é eminente. Por sua vez, o sistema deve apresentar um elevado índice de autonomia, já que as características comportamentais e fisiológicas de um paciente estão em constante mudança e afetam diretamente o modo como deve ocorrer a interação entre o DAV e o sistema cardiovascular do paciente. Sendo assim, há uma necessidade premente de aprimoramento do projeto de sistemas de controle de DAVs autônomos e seguros. A proposta do presente trabalho consiste em aplicar conceitos mecatrônicos para o projeto de um sistema de controle de DAVs e, considerando a natureza dos sinais que indicam a ocorrência de falhas, considerar a teoria de Sistemas a Eventos Discretos (SED), ferramentas de análise de risco e técnicas de diagnóstico e tratamento de falhas para a obtenção de modelos de controle considerando-se uma arquitetura modular e distribuída. Desta forma, foi desenvolvida uma arquitetura de controle supervisório para DAVs considerando características de variações de comportamento do sistema circulatório do paciente e do próprio DAV. Esta arquitetura de controle contempla o diagnóstico e tratamento de falhas desenvolvendo um método para a classificação de falhas e, de acordo com a severidade de cada uma delas é proposto um sistema de controle que atua na regeneração ou degeneração do DAV para um estado seguro, v observando, também, o cumprimento de normas médicas e técnicas de segurança. Para atingir este objetivo, propõe-se uma sistemática para o projeto do sistema de controle para DAVs considerando o aspecto multidisciplinar pertinente a este contexto. A base dessa sistemática consiste em realizar uma efetiva análise de risco do sistema utilizando a ferramenta de estudo HAZOP (Hazard and Operability Studies). A partir do conhecimento obtido sobre o comportamento do sistema em situações críticas desenvolvem-se modelos formais utilizando rede Bayesiana e rede de Petri para o diagnóstico e tratamento das possíveis falhas. O comportamento do DAV controlado pode ser analisado de duas formas: (i) a partir de ensaios in vitro utilizando técnicas de análise por simulação e ferramentas computacionais adequadas, além de testes em simuladores cardiovasculares físicos que emulam interação com o sistema circulatório humano; (ii) a partir de ensaios in vivo em animais que poderão ser utilizados para simular modelos físicos de insuficiência cardíaca e permitir uma avaliação fidedigna dos efeitos do implante do DAV. O procedimento proposto foi aplicado para um caso real de desenvolvimento de um DAV envolvendo uma equipe de pesquisadores da Escola Politécnica da USP e do Instituto Dante Pazanesse de Cardiologia. Assim, é possível obter-se um sistema de controle autônomo e seguro que atenda normas técnicas aderentes a esse assunto e os rigorosos requisitos de projeto impostos a essa classe de sistema. / Nowadays, it is kwon that the several of severe disasters compromising a great variety of systems such as oil platforms, aircrafts or industrial plants, could have been avoided if these systems had controllers designed specifically to maintain the safety levels in case of fault. On the other side, many complications are observed on performing the control of remote systems, where there is no guarantee of real time monitoring of the system, as in space probes or reconnaissance robots. In this context, both obstacles can be found on the control of ventricular assist devices (VAD), which have the role of assisting to pump the blood into the patients circulatory system, in case of irregular heartbeat or heart failure. Devices such as the VAD must possess very high safety levels, as in case of fault, the consequences are severe and might result on the dead of the patient. Nevertheless, these systems must have high degree of autonomy, as the patients physiology and behavior are constantly changing, and these changes impact directly the interactions between the VAD and the patient´s cardiovascular system. Thus, there is a pressing need to improve the design of safe and autonomous control systems for VADs. The present work proposes applying mechatronic concepts to the development of control systems for VADs, considering the nature of the fault indicating signals, as well as the Discrete Event Systems (DES) theory and through the application of tools for risk analysis, and fault diagnostic and treatment techniques aiming the development of control models based on modular and distributed architectures. Thereby, a VAD supervisory control architecture was developed, where the behavior variations of the patient´s circulatory system as well as of the VAD were taken into consideration. This control architecture features the diagnostic and treatment of faults, where methods for faults classification where developed, and according to the severity each fault is proposed a control system that performs the regeneration or degeneration of the VAD to a secure state and is according to medical standards and safety techniques. To achieve this goal is proposed a systematic for the design of the VAD control system considering the multidisciplinary context of the device. The foundation of this systematic is the performance of an effective risk analysis through the use of the toolset known vii as HAZOP (Hazard and Operability Studies). From the knowledge acquired about the system behavior during critical conditions, formal models are developed employing Bayesian Networks and Petri Nets for the diagnostic and treatment of faults. The behavior of the controlled VAD can be analyzed in two possible ways: (i) from in vitro experiments, through the use of simulation analysis tools and proper computational tools, as well as tests on real cardiovascular simulators, where the interactions between the VAD and the human circulatory system can be emulated; (ii) from in vivo experiments, animals can be used to simulate physical models of irregular heartbeat or heart failure and allow reliable valuations of the VAD implant. The proposed procedure was applied on the VAD development, which was performed by a team of researchers from the Escola Politécnica da USP and from the Instituto Dante Pazanesse de Cardiologia. Thus, is possible to achieve an autonomous and safe control system that complies with the applicable technical standards, as well as the strict project requirements for this class of system.

<p>This thesis discusses the representation of bodies in todays non-fiction television in Sweden. I have chosen to focus on deviant bodies (sexual, deformed or unhealthy) on display in reality-shows and documentaries on SVT, TV4 but especially on the commercial channels TV3 and Kanal5. Also discussed are the viewers emotional and bodily reactions. Altough these shows are different from one another in many respects, I argue that there is also a common thread between them. From a sociological and cultural perspective, and with help of some historical examples, I try to illustrate how we view these shows and what their function is. I conclude that the body is a site of powerstruggle and that these shows have many different levels of meaning. We cathegorize and value these deviant bodies but also our own. It is about making creating a ”us and them” and in the long run it has to do with making class and identity. The voyeuristic pleasure in watching these people displayed on TV is made possible from the safe distance of our livingroom.</p>

This study was designed to describe and understand how children perceive and explain mathematical situations. During our work based training we have met several students who have been insecure in the subject of mathematics and therefore come to think that it's difficult and boring. The questions we have asked ourselves are why and how this insecurity occurs. In preschools around the country teachers actively worked to create opportunities for children to meet and discover mathematics. The question is whether the teachers are aware of how children perceive mathematics and how children think in mathematical situations.  We chose to conduct a qualitative study using different methods of data collecting in order to approach the children's world. We have used interviews, observations, experimental circle times and drawings. This study assumes a child’s perspective, because we want to understand their thoughts and perceptions about mathematics. The starting point is the didactic questions what, how and why.  The result of our study indicates that children in preschool perceive mathematics in different ways and that they are unaware that they actually can use and understand athematical situations in the specific context that is preschool. / Studiens syfte var att beskriva och förstå hur barn uppfattar och beskriver matematiska situationer. Vi har under vår verksamhetsförlagda utbildning mött flera elever som har varit osäkra inom matematik och där med tyckt att ämnet är svårt och tråkigt. Vi ställer oss då frågan varför det är så och hur detta tänkesätt uppstår. I förskolan runt om i landet arbetas det aktivt för att skapa möjligheter för barnen att få möta och upptäcka matematik. Frågan är om lärarna är medvetna om hur barn uppfattar matematik och hur barnen tänker kring matematiska situationer.  Vi valde att göra en kvalitativ studie och med hjälp av olika datainsamlingsmetoder närma oss barnens värld. Vi har använt oss av intervjuer, observation, experimentella samlingar och teckningar. Studien utgår ifrån barns perspektiv, då vi vill få förståelse för deras uppfattningar och beskrivningar inom matematik. Utgångspunkten har varit de didaktiska frågeställningarna Vad, Hur och Varför.  Resultatet i vår studie visar att barn i förskolan dagligen använder matematik i verksamheten, men de är omedvetna om att de faktiskt kan, använder och förstår matematiska situationer i den specifika kontexten som är förskola.

This thesis discusses the representation of bodies in todays non-fiction television in Sweden. I have chosen to focus on deviant bodies (sexual, deformed or unhealthy) on display in reality-shows and documentaries on SVT, TV4 but especially on the commercial channels TV3 and Kanal5. Also discussed are the viewers emotional and bodily reactions. Altough these shows are different from one another in many respects, I argue that there is also a common thread between them. From a sociological and cultural perspective, and with help of some historical examples, I try to illustrate how we view these shows and what their function is. I conclude that the body is a site of powerstruggle and that these shows have many different levels of meaning. We cathegorize and value these deviant bodies but also our own. It is about making creating a ”us and them” and in the long run it has to do with making class and identity. The voyeuristic pleasure in watching these people displayed on TV is made possible from the safe distance of our livingroom.

<p>This study was designed to describe and understand how children perceive and explain mathematical situations. During our work based training we have met several students who have been insecure in the subject of mathematics and therefore come to think that it's difficult and boring. The questions we have asked ourselves are why and how this insecurity occurs. In preschools around the country teachers actively worked to create opportunities for children to meet and discover mathematics. The question is whether the teachers are aware of how children perceive mathematics and how children think in mathematical situations.</p><p> We chose to conduct a qualitative study using different methods of data collecting in order to approach the children's world. We have used interviews, observations, experimental circle times and drawings. This study assumes a child’s perspective, because we want to understand their thoughts and perceptions about mathematics. The starting point is the didactic questions what, how and why.</p><p> The result of our study indicates that children in preschool perceive mathematics in different ways and that they are unaware that they actually can use and understand athematical situations in the specific context that is preschool.</p> / <p>Studiens syfte var att beskriva och förstå hur barn uppfattar och beskriver matematiska situationer. Vi har under vår verksamhetsförlagda utbildning mött flera elever som har varit osäkra inom matematik och där med tyckt att ämnet är svårt och tråkigt. Vi ställer oss då frågan varför det är så och hur detta tänkesätt uppstår. I förskolan runt om i landet arbetas det aktivt för att skapa möjligheter för barnen att få möta och upptäcka matematik. Frågan är om lärarna är medvetna om hur barn uppfattar matematik och hur barnen tänker kring matematiska situationer.</p><p> Vi valde att göra en kvalitativ studie och med hjälp av olika datainsamlingsmetoder närma oss barnens värld. Vi har använt oss av intervjuer, observation, experimentella samlingar och teckningar. Studien utgår ifrån barns perspektiv, då vi vill få förståelse för deras uppfattningar och beskrivningar inom matematik. Utgångspunkten har varit de didaktiska frågeställningarna Vad, Hur och Varför.</p><p> Resultatet i vår studie visar att barn i förskolan dagligen använder matematik i verksamheten, men de är omedvetna om att de faktiskt kan, använder och förstår matematiska situationer i den specifika kontexten som är förskola.</p>

Les canaux vocodés sont les canaux de communications dédiés à la voix et dans lesquels le signal traverse divers équipements destinés au transport de la voix tels que des codeurs de parole, des détecteurs d'activité vocale (VAD), des systèmes de transmission discontinue (DTX). Il peut s'agir de systèmes de communications téléphoniques filaires ou mobiles (réseaux cellulaires 2G/3G, satellites INMARSAT...) ou de voix sur IP. Les codeurs de parole dans les normes récentes pour les réseaux de téléphonie mobiles ou de voix sur IP font appel à des algorithmes de compression dérivés de la technique CELP (Code Excited Linear Prediction) qui permettent d'atteindre des débits de l'ordre de la dizaine de Kb/s bien inférieurs aux codeurs des réseaux téléphoniques filaires (typiquement 64 ou 32 Kb/s). Ces codeurs tirent leur efficacité de l'utilisation de caractéristiques spécifiques aux signaux de parole et à l'audition humaine. Aussi les signaux autres que la parole sont-ils généralement fortement distordus par ces codeurs. La transmission de données sur les canaux vocodés peut être intéressante pour des raisons liées à la grande disponibilité des canaux dédiés à la voix et pour des raisons de discrétion de la communication (sécurité). Mais le signal modulé transmis sur ces canaux vocodés est soumis aux dégradations causées par les codeurs de parole, ce qui impose des contraintes sur le type de modulation utilisé. Cette thèse a porté sur la conception et l'évaluation de modulations permettant la transmission de données sur les canaux vocodés. Deux approches de modulations ont été proposées pour des applications correspondant à des débits de transmission possibles assez différents. La principale application visée par la thèse concerne la transmission de parole chiffrée, transmission pour laquelle le signal de parole est numérisé, comprimé à bas débit par un codeur de parole puis sécurisé par un algorithme de cryptage. Pour cette application, nous nous sommes focalisés sur les réseaux de communications utilisant des codeurs CELP de débits supérieurs à la dizaine de Kb/s typiquement les canaux de communication mobiles de deuxième ou troisième génération. La première approche de modulation proposée concerne cette application. Elle consiste à utiliser des modulations numériques après optimisation de leurs paramètres de façon à prendre en compte les contraintes imposées par le canal et à permettre des débits et des performances en probabilité d'erreur compatibles avec la transmission de parole chiffrée (typiquement un débit supérieur à 1200 b/s avec un BER de l'ordre de 10-3). Nous avons montré que la modulation QPSK optimisée permet d'atteindre ces performances. Un système de synchronisation est aussi étudié et adapté aux besoins et aux contraintes du canal vocodé. Les performances atteintes par la modulation QPSK avec le système de synchronisation proposé, ainsi que la qualité de la parole sécurisée transmise ont été évalués par simulation et validés expérimentalement sur un canal GSM réel grâce à un banc de test développé dans la thèse.La deuxième approche de modulation a privilégié la robustesse du signal modulé lors de la transmission à travers un codeur de parole quelconque, même un codeur à bas débit tels que les codeurs MELP à 2400 ou 1200 b/s. Dans ce but, nous avons proposé une modulation effectuée par concaténation de segments de parole naturelle associée à une technique de démodulation qui segmente le signal reçu et identifie les segments de parole par programmation dynamique avec taux de reconnaissance élevé. Cette modulation a été évaluée par simulation sur différents codeurs de parole. Elle a aussi été testée sur des canaux GSM réels. Les résultats obtenus montrent une probabilité d'erreur très faible quelque soit le canal vocodé et le débit des codeurs de parole utilisés mais pour des débits possibles relativement faibles. Les applications envisageables sont restreintes à des débits typiquement inférieurs à 200 b/s.Enfin nous nous sommes intéressés aux détecteurs d'activité vocale dont l'effet peut-être très dommageable pour les signaux de données. Nous avons proposé une méthode permettant de contrer les VAD utilisés dans les réseaux GSM. Son principe consiste à rompre la stationnarité du spectre du signal modulé, stationnarité sur laquelle s'appuie le VAD pour décider que le signal n'est pas de la parole

The following essay examines if five Swedish textbooks aimed for religious studies in upper secondary school might show similar flaws to those presented by the Swedish Schools Inspectorate in their review of religious studies conducted in 2012. The method used in this essay is a qualitative study of Swedish textbooks influenced by Lantz definition of wide and thin ethics. This in practice means that I have analysed the five Swedish textbooks using thin and broad ethics while conducting the analysis of the five. The purpose of the essay was to see if the flaws presented in “Mer än vad du kan tro” regarding ethics and moral education might be present in Swedish textbooks as well. My essay shows that four out of the five Swedish textbooks included in the study show signs of the flaws presented in “Mer än vad du kan tro” and that the books apply thin and broad ethics to a varying degree.

Atualmente, sabe-se que grande parte dos acidentes graves ocorridos envolvendo uma diversidade de sistemas como plataformas de petróleo, aeronaves ou plantas de processos industriais, poderiam ser evitados caso possuíssem dispositivos de controle projetados especificamente para manter a segurança durante a ocorrência de falhas no funcionamento dos mesmos. Por outro lado, observam-se complicações em realizar o controle de sistemas remotos em que é possível não haver garantia de monitoração em tempo real, como o caso de sondas espaciais ou robôs de exploração. Neste contexto, podem-se encontrar ambas as dificuldades no controle do funcionamento de um Dispositivo de Assistência Ventricular (DAV) que desempenha a função de auxiliar o bombeamento de sangue para o sistema circulatório de um paciente com insuficiência cardíaca. Este tipo de dispositivo, quando usado para terapia de destino, deve apresentar um elevado nível de segurança, pois, caso haja falha, o risco de morte é eminente. Por sua vez, o sistema deve apresentar um elevado índice de autonomia, já que as características comportamentais e fisiológicas de um paciente estão em constante mudança e afetam diretamente o modo como deve ocorrer a interação entre o DAV e o sistema cardiovascular do paciente. Sendo assim, há uma necessidade premente de aprimoramento do projeto de sistemas de controle de DAVs autônomos e seguros. A proposta do presente trabalho consiste em aplicar conceitos mecatrônicos para o projeto de um sistema de controle de DAVs e, considerando a natureza dos sinais que indicam a ocorrência de falhas, considerar a teoria de Sistemas a Eventos Discretos (SED), ferramentas de análise de risco e técnicas de diagnóstico e tratamento de falhas para a obtenção de modelos de controle considerando-se uma arquitetura modular e distribuída. Desta forma, foi desenvolvida uma arquitetura de controle supervisório para DAVs considerando características de variações de comportamento do sistema circulatório do paciente e do próprio DAV. Esta arquitetura de controle contempla o diagnóstico e tratamento de falhas desenvolvendo um método para a classificação de falhas e, de acordo com a severidade de cada uma delas é proposto um sistema de controle que atua na regeneração ou degeneração do DAV para um estado seguro, v observando, também, o cumprimento de normas médicas e técnicas de segurança. Para atingir este objetivo, propõe-se uma sistemática para o projeto do sistema de controle para DAVs considerando o aspecto multidisciplinar pertinente a este contexto. A base dessa sistemática consiste em realizar uma efetiva análise de risco do sistema utilizando a ferramenta de estudo HAZOP (Hazard and Operability Studies). A partir do conhecimento obtido sobre o comportamento do sistema em situações críticas desenvolvem-se modelos formais utilizando rede Bayesiana e rede de Petri para o diagnóstico e tratamento das possíveis falhas. O comportamento do DAV controlado pode ser analisado de duas formas: (i) a partir de ensaios in vitro utilizando técnicas de análise por simulação e ferramentas computacionais adequadas, além de testes em simuladores cardiovasculares físicos que emulam interação com o sistema circulatório humano; (ii) a partir de ensaios in vivo em animais que poderão ser utilizados para simular modelos físicos de insuficiência cardíaca e permitir uma avaliação fidedigna dos efeitos do implante do DAV. O procedimento proposto foi aplicado para um caso real de desenvolvimento de um DAV envolvendo uma equipe de pesquisadores da Escola Politécnica da USP e do Instituto Dante Pazanesse de Cardiologia. Assim, é possível obter-se um sistema de controle autônomo e seguro que atenda normas técnicas aderentes a esse assunto e os rigorosos requisitos de projeto impostos a essa classe de sistema. / Nowadays, it is kwon that the several of severe disasters compromising a great variety of systems such as oil platforms, aircrafts or industrial plants, could have been avoided if these systems had controllers designed specifically to maintain the safety levels in case of fault. On the other side, many complications are observed on performing the control of remote systems, where there is no guarantee of real time monitoring of the system, as in space probes or reconnaissance robots. In this context, both obstacles can be found on the control of ventricular assist devices (VAD), which have the role of assisting to pump the blood into the patients circulatory system, in case of irregular heartbeat or heart failure. Devices such as the VAD must possess very high safety levels, as in case of fault, the consequences are severe and might result on the dead of the patient. Nevertheless, these systems must have high degree of autonomy, as the patients physiology and behavior are constantly changing, and these changes impact directly the interactions between the VAD and the patient´s cardiovascular system. Thus, there is a pressing need to improve the design of safe and autonomous control systems for VADs. The present work proposes applying mechatronic concepts to the development of control systems for VADs, considering the nature of the fault indicating signals, as well as the Discrete Event Systems (DES) theory and through the application of tools for risk analysis, and fault diagnostic and treatment techniques aiming the development of control models based on modular and distributed architectures. Thereby, a VAD supervisory control architecture was developed, where the behavior variations of the patient´s circulatory system as well as of the VAD were taken into consideration. This control architecture features the diagnostic and treatment of faults, where methods for faults classification where developed, and according to the severity each fault is proposed a control system that performs the regeneration or degeneration of the VAD to a secure state and is according to medical standards and safety techniques. To achieve this goal is proposed a systematic for the design of the VAD control system considering the multidisciplinary context of the device. The foundation of this systematic is the performance of an effective risk analysis through the use of the toolset known vii as HAZOP (Hazard and Operability Studies). From the knowledge acquired about the system behavior during critical conditions, formal models are developed employing Bayesian Networks and Petri Nets for the diagnostic and treatment of faults. The behavior of the controlled VAD can be analyzed in two possible ways: (i) from in vitro experiments, through the use of simulation analysis tools and proper computational tools, as well as tests on real cardiovascular simulators, where the interactions between the VAD and the human circulatory system can be emulated; (ii) from in vivo experiments, animals can be used to simulate physical models of irregular heartbeat or heart failure and allow reliable valuations of the VAD implant. The proposed procedure was applied on the VAD development, which was performed by a team of researchers from the Escola Politécnica da USP and from the Instituto Dante Pazanesse de Cardiologia. Thus, is possible to achieve an autonomous and safe control system that complies with the applicable technical standards, as well as the strict project requirements for this class of system.

Orientador : Carlos Kenichi Suzuki / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-04T01:44:29Z (GMT). No. of bitstreams: 1 Ono_Eduardo_M.pdf: 3494337 bytes, checksum: 6a111a737f2e9b27797fca1dc7c3fe90 (MD5) Previous issue date: 2004 / Resumo: Um novo processo VAD ("Vapor-phase Axial Deposition"), em desenvolvimento no Laboratório Ciclo Integrado do Quartzo - LIQC, FEM, UNICAMP, introduz uma série de inovações tecnológicas e maior viabilidade econômica sobre os atuais processos de fabricação de fibra óptica. Para a produção de uma fibra de alta qualidade, a uniformidade geométrica da preforma porosa, gerada na etapa de deposição do processo, possui grande relevância na uniformidade das características da fibra final, tais como a atenuação e a dispersão. Para o controle da geometria da preforma em deposição, desenvolveu-se um sistema em LabVIEW, para a plataforma PC, para atuar continuamente e em tempo real na etapa de deposição de modo a manter o diâmetro da preforma constante. Em sua essência, o sistema de controle realimentado, baseado no controlador PID, atua na velocidade do mecanismo de posicionamento da preforma em função do valor do diâmetro na região inferior da preforma. Esse diâmetro é obtido pelo processamento da imagem adquirida por uma câmera de vídeo CCD da região da preforma em deposição. Embora tenha sido desenvolvido para a escala laboratorial, o sistema mostrou bom desempenho e estabilidade, podendo ser empregado na produção industrial em grande escala de preformas para fibra óptica. Nesse sistema, variações dimensionais no diâmetro da preforma da ordem de 0,3 mm são corrigidos, obtendo-se uma precisão cinco vezes maior quando comparado a sistemas convencionais, favorecendo uma menor incidência de rejeitos de produção de preformas e, conseqüentemente, menor custo de produção / Abstract: An advanced V AD (Vapor-phase Axial Deposition) technique has been developed at Laboratory of Integrated Quartz Cycle - LIQC - FEM - UNICAMP. It introduces a series of technological innovations with a greater economical viability over actual optical fiber manufacturing processes. For a high quality optical fiber production, several steps and process parameters must be carefully set. The geometrical uniformity of the preform during the deposition stage is one of the most important parameter for the final uniformity, which determines the characteristics of the final fiber in terms of attenuation and dispersion. To control the preform geometry during the deposition, a computer system based on Lab VIEW platform was developed, to act continuously and in real time on the deposition stage, in order to maintain constant the preform diameter. In its essence, the feedback system, based on PID controller, acts on the speed of the preform positioning mechanism, according to the value of the diameter detected in. the deposition region. This diameter is obtained through the image processing grabbed from a CCD video camera. Although, it was developed in a laboratorial scale, the system showed a good performance and stability, which can be applied on an industrial mass production scale for fiber optics. In this system, dimensional variations in the order of 0.3 mm on the preform diameter can be corrected, that corresponds to a precision about 5 times better than that achieved by conventional industrial systems, with a benefit of a lower incidence of production rejects and, therefore, a lower production cost / Mestrado / Materiais e Processos de Fabricação / Mestre em Engenharia Mecânica

This diploma thesis discusses the issue of Voice Activity Detection. There are two types of detectors described: energetic and statistics. Their funktionality is proved in the Matlab environment. Further, the implemetation of VADs is made through C language with standard libraries and GSL open-source libraries. The realized algorithms are compared in the scope of processing time of computation, memory management and a single mathematical operations stress. Also a comparism of the processing time according to segment length was made.