Chronic liver disease is a worldwide health problem, and hepatic fibrosis (HF) is one of the hallmarks of the disease. The current reference standard for diagnosing HF is biopsy followed by pathologist examination; however, this is limited by sampling error and carries a risk of complications. Pathology diagnosis of HF is based on textural change in the liver as a lobular collagen network that develops within portal triads. The scale of collagen lobules is characteristically in the order of 1 to 5 mm, which approximates the resolution limit of in vivo gadolinium-enhanced magnetic resonance imaging in the delayed phase. We use MRI of formalin-fixed human ex vivo liver samples as phantoms that mimic the textural contrast of in vivo Gd-MRI. We have developed a local texture analysis that is applied to phantom images, and the results are used to train model observers to detect HF. The performance of the observer is assessed with the area-under-the-receiver-operator-characteristic curve (AUROC) as the figure-of-merit. To optimize the MRI pulse sequence, phantoms were scanned with multiple times at a range of flip angles. The flip angle that was associated with the highest AUROC was chosen as optimal for the task of detecting HF. (C) The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

Viewshed refers to the calculation and visualisation of what part of a terrain isvisible from a given observer point. It is used within many fields, such as militaryplanning or telecommunication tower placement. So far, no general fast methodsexist for calculating the viewshed for multiple observers that may for instancerepresent a road within the terrain. Additionally, if the terrain contains over-lapping structures such as man-made constructions like bridges, most currentviewshed algorithms fail. This report describes two novel methods for viewshedcalculation using multiple observers for terrain that may contain overlappingstructures. The methods have been developed at Vricon in Linköping as a Mas-ter’s Thesis project. Both methods are implemented using the graphics program-ming unit and the OpenGL graphics library, using a computer graphics approach.Results are presented in the form of figures and images, as well as running timetables using two different test setups. Lastly, future possible improvements arealso discussed. The results show that the first method is a viable real-time solu-tion and that the second method requires some additional work.

Nous proposons dans ces travaux, une solution aux problèmes de longue date posés par le control sans capteur d’une machine électrique. Cette solution consiste à élaborer un contrôleur asymptotiquement stable qui régule la vitesse du moteur en mesurant uniquement les coordonnées électriques. Nous l’avons appliqué à un moteur synchrone à aimant permanent non saillant, perturbé par un couple de charge constant non connu. Le schéma proposé est un observateur non linéaire d’ordre 4, basé sur le control qui ne dépend pas d’opérations non robustes intrinsèques au système, comme l’intégration de boucle ouverte à un système dynamique et ce schéma peut être facilement intégrée en temps réel. Le contrôleur est facile à commander par l’ajustement du gain qui détermine directement le taux de convergence de la position et de la vitesse et charge le couple d’observateurs. Les simulations et les résultats expérimentaux mettent en évidences les bonnes performances ainsi que la robustesse des paramètres d’incertitudes du schéma que nous proposons. La comparaison par simulation avec un contrôleur sans capteur à champ orienté présenté récemment dans la littérature, a également été effectuée. La thèse se termine par des remarques de conclusion et des propositions de sujet de recherche s’inscrivant dans la continuité de ces travaux. / A solution to the longstanding problem of sensorless control of an electrical machine is provided in this work. That is, the construction of an asymptotically stable controller that regulates the mechanical speed of the motor, measuring only the electrical coordinates. The result is presented for a non-salient permanent magnet synchronous motor perturbed by an unknown constant load torque. The proposed scheme is a fourth order nonlinear observer-based controller that does not rely on-intrinsically nonrobust-operations like open-loop integration of the systems dynamical model nor signal differentiation, and can be easily implemented in real time. The controller is easy to commission, with the tuning gains directly determining the convergence rates of the position, speed and load torque observers. Simulation and experimental results that illustrate the good performance, as well as the robustness to parameter uncertainty, of the scheme are presented. A simulated comparison with a sensorless field-oriented controller, recently proposed in the drives literature, is also carried out. The thesis is closed with some concluding remarks and some potential research topics generated from this work.

Este trabalho apresenta através de simulação um estudo comparativo de estimadores de velocidade de motor de indução trifásico por meio de observadores de estado e da técnica do filtro de Kalman. É realizada uma análise comparativa de desempenho das estratégias de estimação determinísticas e estocásticas, com observadores adaptativos e estimadores baseados na teoria do filtro de Kalman estendido, respectivamente. A realização do trabalho visa a constatação dos procedimentos de elaboração, de operação e de aplicação destas técnicas de estimação usando um exemplo real com fins de ilustrar o ensino de controle e acionamento de máquinas elétricas. As simulações foram realizadas através do Matlab/Simulink com a utilização das ferramentas do Power System Blockset (PSB) e o algoritmo dos estimadores é escrito em programa Matlab e executado por uma função S-Function. Os resultados de simulação demonstram a eficiência de cada um dos estimadores propostos, no que se refere ao comportamento transitório, robustez a ruídos e variações nos parâmetros do motor. / This works presents through of the simulation a comparative study of the sensorless of speed estimation of induction three-phase motor using state observer and Kalman filter. A comparative analysis of the performance of the deterministic and stochastic estimation strategies using adaptive observers and estimators based on extended Kalman filter was realized. The work aims to verify the procedure of the elaboration, operation and application of such estimation techniques using a real example to illustrate the teaching of the control and driving of electric machines. The simulations where performed using Matlab/Simulink with Power System Blockset (PSB) toolboxes and the estimators are programmed as S-Function Matlab. The results indicate the effectiveness of the proposed estimators, according to the transient behavior, robustness to noise and ability to handle parametric variations.

Esta pesquisa desenvolve uma análise crítica a partir de uma noção histórico-teórica do processo de construção da relação das pessoas com a mídia na contemporaneidade e está dividida em três momentos: o Observador no século 19; o Espectador no século 20; e o Usuário no século 21. Assume que estes constituem três sujeitos comunicacionais, possuem trajetórias interligadas e podem ser vistos como um sujeito múltiplo. O trabalho parte dos seguintes pressupostos: a transformação do comportamento dos sujeitos; o acúmulo de percepções e conhecimentos; e as mudanças nos modos de ver e nas maneiras de se relacionar que se dão a partir de uma construção sociocultural, política e econômica. Busca compreender a existência de um Observador/Espectador/Usuário e as mediações tecnológicas que lhe servem como contexto. Vê o Usuário: a partir do Flanêur de Benjamin - como uma referência comunicacional ao sujeito/objeto na formação do seu olhar; como reconfiguração do sujeito/receptor na história e de sua relação com a mídia e com a sociedade; como a dimensão tecnológica permeia a diferenciação dos sujeitos comunicacionais e o contexto social no qual estão inseridos, privilegiando a tecnologia e em seu lugar político e social, e de como o comportamento deste sujeito pode ser atribuído a esses lugares. Trabalha a Percepção na medida em que se aproxima do Usuário/Flanêur numa conjugação em que os dois se distinguem mesmo que em tempos e circunstâncias diversas na experiência comunicacional. / This research develops a critical analysis from a historical-theoretical perception of the construction process of people relation with the Media in the contemporary world and it is divided in three moments: the Observer in the 19th century; the Spectator in the 20th century and the User in the 21st century. It accepts that these three communication subjects share connected paths and can also be seen as a multiple subject. This work is based in the following assumptions: the transition in the subjects behaviour; the accumulation of perception and knowledge; and the changes in the ways of seeing and in the ways the relationships happened from a sociocultural, political and economic structure point of view. The research aims to understand the existence of an Observer/Spectator/User and the technological mediations that are used as a background. It sees the User from: Benjamin\'s Flanêur point of view - as a communicational reference for the development of the subject/object in the construction of the way he sees; as a reconfiguration of the subject/recipient in history and its relation with the Medias and with the society; how the technological dimension pervades the variation between the communication subjects and in the social context in which they are located, with a particular emphasis in technology, and in his political and social place and of how this subjects\' behaviour is ascribed to these places. This research also explores the Perception to the extent that it approaches the User/Flanêur in a combination in which the two of them distinguish from each other in the communication experience even in different times and circumstances.

Este trabalho apresenta através de simulação um estudo comparativo de estimadores de velocidade de motor de indução trifásico por meio de observadores de estado e da técnica do filtro de Kalman. É realizada uma análise comparativa de desempenho das estratégias de estimação determinísticas e estocásticas, com observadores adaptativos e estimadores baseados na teoria do filtro de Kalman estendido, respectivamente. A realização do trabalho visa a constatação dos procedimentos de elaboração, de operação e de aplicação destas técnicas de estimação usando um exemplo real com fins de ilustrar o ensino de controle e acionamento de máquinas elétricas. As simulações foram realizadas através do Matlab/Simulink com a utilização das ferramentas do Power System Blockset (PSB) e o algoritmo dos estimadores é escrito em programa Matlab e executado por uma função S-Function. Os resultados de simulação demonstram a eficiência de cada um dos estimadores propostos, no que se refere ao comportamento transitório, robustez a ruídos e variações nos parâmetros do motor. / This works presents through of the simulation a comparative study of the sensorless of speed estimation of induction three-phase motor using state observer and Kalman filter. A comparative analysis of the performance of the deterministic and stochastic estimation strategies using adaptive observers and estimators based on extended Kalman filter was realized. The work aims to verify the procedure of the elaboration, operation and application of such estimation techniques using a real example to illustrate the teaching of the control and driving of electric machines. The simulations where performed using Matlab/Simulink with Power System Blockset (PSB) toolboxes and the estimators are programmed as S-Function Matlab. The results indicate the effectiveness of the proposed estimators, according to the transient behavior, robustness to noise and ability to handle parametric variations.

Sistemas de Posicionamento Dinâmico (SPD) são sistemas de controle que visam assegurar que um veículo oceânico se mantenha em uma determinada posição ou acompanhe uma trajetória de referência, mediante o emprego exclusivo de seus propulsores. Um SPD pode ser desmembrado em vários módulos específicos, com funções bem determinadas. Os módulos mais importantes são os sistemas de medição de posição e aproamento, o estimador de estados, o controlador e o algoritmo de alocação de empuxos. Atualmente, o Filtro de Kalman Estendido (FKE) é o estimador padrão para todos os SPD comercialmente disponíveis. Entretanto, o emprego do FKE implica em uma série de desvantagens. A sintonização do sistema é demorada e difícil, em função do elevado número de parâmetros de sintonização. Estabilidade assintótica global não pode ser conferida ao sistema. Adicionalmente, é necessário aplicar a técnica de programação de ganhos, uma vez que as equações cinemáticas de movimento do modelo devem ser linearizadas para aproximadamente 36 ângulos de guinada. A fim de eliminar estes óbices, o presente estudo propõe o desenvolvimento de um SPD totalmente não-linear, composto por um observador passivo não-linear e um controlador não-linear backstepping. / Dynamic Positioning Systems (DPS) are control systems used to maintain the vessel on a desired position or pre-defined path exclusively by means of active thrusters. A DPS can be separated into a set of dedicated modules with designated tasks. The most significant modules are the position and heading measurement systems, the state estimator, the controller and the thrust allocation algorithm. Nowadays, the Extended Kalman Filter (EKF) is the standard state estimator for all commercial DPS. However, the EKF technique presents several drawbacks. There is a large number of tuning parameters which requires a time-consuming tuning procedure. Global asymptotic stability cannot be assured to the system. Furthermore, it requires the use of a gain-scheduling technique, since the model is linearized about approximately 36 yaw angles due to the kinematics equations of motions. To solve these problems, this study proposes the development of a fully nonlinear DPS comprising a passive nonlinear observer and a nonlinear backstepping controller.

Um grande número de crianças com menos de quatro anos de idade procura serviços de atendimento fonoaudiológico por estarem apresentando suspeitas de dificuldades quanto ao desenvolvimento adequado da linguagem. Entretanto, apesar de tal demanda, o fonoaudiólogo clínico ainda não encontra à sua disposição procedimentos sistematizados de avaliação que possam auxiliá-lo no sentido de promover um diagnóstico adequado. No intuito de contribuir para o delineamento do perfil comunicativo e cognitivo de crianças pequenas, este trabalho teve por objetivo obter valores de referência para protocolo de observação comportamental (PROC) sobre o desenvolvimento de habilidades comunicativas e de esquemas simbólicos em crianças com desenvolvimento típico de linguagem. Foram avaliadas 44 crianças entre 24 e 47 meses de ambos os gêneros, selecionadas em escolas de educação infantil, por meio de triagem do desenvolvimento global Denver II (TTDD II) e questionário com os pais. Todas as crianças foram filmadas durante 30 minutos em interação com um adulto em atividade envolvendo brinquedos. As gravações foram analisadas por meio do PROC. A análise estatística descreveu valores de média, mediana, valores mínimos e máximos. Foi utilizado o teste T de Student para comparação das idades. Foi considerado significativo valor de p<0,05. No que tange às habilidades comunicativas, as crianças do estudo mostraram evolução com a idade (média para três e dois anos, respectivamente: 58,12 e 51,44), apesar de não ter sido encontrada diferença estatisticamente significante para as faixas etárias comparadas (p=0,486). Na análise dos subitens habilidades dialógicas e funções comunicativas, a média das pontuações obtidas foram semelhantes para as duas faixas etárias, sendo que a função mais observada foi a instrumental para ambas. Já para os subitens meios de comunicação e nível de contextualização da linguagem, as crianças de três anos apresentaram maior pontuação. Quanto ao item compreensão verbal, as crianças de três anos obtiveram melhor desempenho que as de dois (respectivas médias: 59,41 e 50,70), havendo diferença estatisticamente significante (p=0,0000020). Em relação ao item aspectos do desenvolvimento cognitivo, as crianças de três anos apresentaram melhor desempenho em comparação com as de dois (respectivas médias: 44,53 e 31,96), havendo diferença estatisticamente significante entre as pontuações obtidas (p=0,00364), mostrando que as crianças evoluem na hierarquia do simbolismo. Em relação aos subitens forma de manipulação dos objetos, nível de desenvolvimento do simbolismo, nível de organização do brinquedo e imitação, as crianças de três anos obtiveram melhor pontuaçao que as de dois, excetuando-se no subitem Imitação. Portanto, na pontuação total do instrumento PROC, considerando todos os três itens avaliados, as crianças de três anos obtiveram maior pontuação em comparação às de dois, havendo diferença estaticamente significante entre os valores obtidos paras as faixas etárias, excetuando-se para o item Habilidades Comunicativas. A obtenção de valores de referência para o PROC veio combinar análise qualitativa e quantitativa, contribuindo, além do diagnóstico, para o acompanhamento objetivo de processos terapêuticos. / A large number of children under 4 years old go to speech therapy services because they are presenting difficulties on appropriate language development. However, although this demand, the speech pathologist does not have at his disposal systematized assessment procedures that can assist in promoting a proper diagnosis, differentiating possible language problems affecting this age group, or even make the appropriate guidance of the case, in terms of therapy, in terms of referrals to other professionals. In order to create standard procedures to contribute to a better evaluation of language development in children, this study aims to obtain reference values for behavioral observation protocol (PROC) on the development of communicative and symbolic schemes of children with typical language development. It has been evaluated 44 children between 24 and 47 months, both genders, selected from three different primary schools using Denver II development screening methodology (TTDD II) and also a questionnaire submitted to the parents. All children were filmed 30 minutes interacting with the researcher and playing with toys. The recordings were analyzed through PROC. The values that compose the statistical analysis are average, median, maximums and minimums. It has been used the T Student test to compare the ages. The significance was p<0.05. In regards to communication abilities, children had shown an evolution with age (average of three and two years old respectively 58.12 and 51.44), even though no significant statistical change was found in the range of ages compared (p=0.486). In the sub-item analysis performed over dialogical abilities and communication functions, the averages were similar for both age groups, being the instrumental function the one most observed. For the sub-items communication medium and language contextualization level, the three years old children had higher scores. In regards do verbal comprehension, children aged three presented better results than children aged two (averages: 59.41 and 50.70 respectively) with statistical significance variance (p=0.0000020). In cognitive development, three years old children presented better performance compared to two years old children (averages: 44.53 and 31.96 respectively), significant difference between results (p=0.00364) showing that children evolve in the hierarchy of symbolism. In the sub-items object manipulation, symbolism development level, toys organization level and imitation, three years old children had also better score than two years old children, except for imitation. Therefore, the total score of PROC, considering the three items evaluated, showed better results for three years old children compared to two years old children with significant statistical difference between the group ages, except for communication abilities. The values obtained in PROC combined qualitative and quantitative analysis, contributing, besides diagnosis, to a more objective therapeutic process evaluation.

An unknown input observer provides perfect asymptotic tracking of the state of a system affected by unknown inputs. Such an observer exists (possibly requiring a delay in estimation) if and only if the system satisfies a property known as strong detectability. In this thesis, we consider the problem of selecting (at design-time) a minimum cost subset of sensors from a given set to make a given system strongly detectable. We show this problem is NP-hard even when the system is stable. Furthermore, we show it is not possible to approximate the minimum cost within a factor of log(n) in polynomial-time (unless P=NP). However, we prove if a given system (with a selected set of sensors) is already strongly detectable, finding the smallest set of additional sensors to install to obtain a zero-delay observer can be done in polynomial time. Next we consider the problem of attacking a set of deployed sensors to remove the property of strong detectability. We show finding the smallest number of sensors to remove is NP-hard. Lastly through simulations, we analyze two greedy approaches for approximating the strong detectability sensor selection problem.

Data collected by Australian observers, combined with logbook data supplied by all Japanese vessels fishing in the Australian Fishing Zone were used to estimate the total seabird catch and catch rates (and associated variances) within the Australian Fishing Zone by season and area. The species composition of subsamples of captured seabirds was used in conjunction with the estimates of total by-catch to provide estimates of by-catch by species. The total by-catch of all seabird species by Japanese longline within Australian waters was estimated to be 2,981 (cv 17%) for the 1992 fishing year, 3,590 (cv 15%) in 1993 and 2,817 (cv 19%) in 1994. However, the observed seabird bycatch may underestimate the total number of seabirds killed by 27%. The increase in total seabird by-catch between 1992 and 1993 is partly due to the use of monofilament nylon longline gear by two vessels in 1993, and the decrease from 1993 to 1994 was mainly due to a corresponding reduction in fishing effort. For the three years examined, 78% of the total seabird by-catch was albatrosses, with black-browed albatross (Diomedea melanophrys) and shy albatross (D. cauta) caught in the greatest numbers. Catches of yellow-nosed albatross (D. chlororhynchos), wandering albatross (D. exulans}, and grey-headed albatross (D. chrysostoma) were also substantial. The proportions of individual species caught showed considerable inter-annual variability. Most seabirds caught and killed by longline fishing are captured during line setting. Data collected by the observers were also used to determine the influence of various environmental factors and mitigation measures on seabird catch rates. Generalised linear models were used to determine the statistical significance of the effect of each factor on the seabird catch rate. Results show that the environmental factor that has the most influence is whether line setting was carried out at night or during the day. For the data examined, the chance of catching seabirds during day sets was five times greater than for night sets. For night sets, the chance of catching seabirds during the full half-phase of the moon was five times greater than during the new half-phase. Other environmental factors with significant effects were the area and season fished. Wind, cloud and sea conditions were not found to have a significant influence. Considerable variation in the seabird by-catch rate among vessels was found, which is probably due to differences in their implementation of mitigation measures, as well as the clumped distribution of seabirds by area and time. Interannual variation in the by-catch rate was found to be statistically significant but the differences among years was small in comparison to other factors. An examination of the influence of mitigation measures for sets made during the day in summer in the Tasmanian area showed that the level of bait thawing and unidentified factors related to individual vessels were most significant in determining the seabird by-catch rate, followed by the use of a bait throwing device. It was not possible to examine the influence of the use of bird scaring tori poles and lines as these were used during all sets examined in detail. For this data set, the amount of cloud cover had an influence, while moon phase, sea conditions and wind strength did not.