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Integrating computer vision into a robotic system can provide a closed-loop controlled platform that increases the robustness of a robot's motion. This integration is also known as visual servo control or visual servoing. Visual servoing of a robot manipulator in real-time presents complex engineering problems with respect to both control and image processing particularly when we want the robot arm to perform complicated tasks such as portrait drawing. In my research, the implementation of torque feedback control and Image-based Visual Servoing (IBVS) approaches are proposed to improve previous open-loop portrait drawing tasks performed by Betty, a humanoid robot in the Autonomous Agent Lab, University of Manitoba. The implementations and evaluations of hardware, software and kinematic models are discussed in this document. I examined the problem of estimating ideal edges joining points in a pixel reduction image for an existing point-to-point portrait drawing humanoid robot, Betty. To solve this line drawing problem, two automatic sketch generators are presented. First, a modified Theta-graph, called Furthest Neighbour Theta-graph (FNTG). Second, an extension of the Edge Drawing Lines algorithm (EDLines), called Extended Edge Drawing Lines (eEDLines). The results show that the number of edges in the resulting drawing is significantly reduced without degrading the detail of the output image. The other main objective of this research is to propose the extension of the drawing robot project to further develop a robust visual servoing system for Betty to correct any drawing deviation in real-time as a human does. This is achieved by investigating and developing robust feature (lines and shading) extraction approaches for real-time feature tracking of IBVS in combination with adequate torque feedback in the drawing task.

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Switched reluctance motors with fully pitched windings are a relatively recent advancementin motor technology having only been in existences ince the early 1990's. They have been shown previously to offer greater torque per unit copper loss, and hence higher torque density, than conventional switched reluctance machines with short pitched windings. Early work by Mecrow and Barrass has demonstrated operation of prototype machines, developed and assessedv arious methods of control strategy, and made some comparisons of machine efficiency and inverter rating. The results presented here build on this early work by, in essence, examining the aspects of machine design, control strategy and inverter topology that affect drive performance and cost. Detailed comparisons of inverter rating and machine efficiency are made under equal conditions with the various methods of excitation that are possible. This is achieved with results from a test rig, including temperature rise tests, and the use of accurate dynamic simulation. The latter is developed to accurately model the motor with its strong mutual coupling between phases, various inverter topologies and the details of the controller such as digital PWM. As a result comparisons between simulated and measured results are shown to be very good. The fundamentals of machine design are examined with a view to optimising the machine for fully pitched windings. Previous work has indicated that good results are achieved when a conventional machine is simply rewound, however it is shown that further improvements can be made. Proposals are made to improve the drive in terms of both machine performance and power electronic rating. A search method is proposed that optimises current waveshape for either maximum torque per unit copper loss, or smooth torque for lowest loss. The method works over the entire speed range, as the rate of change of flux linkage is taken into account. Three alternative power electronic converters are developed, one of which is also particularly suitable for the short pitched winding machine. Aspects of silicon rating, current controllability, and current sensor requirements are discussed.

The objective of this thesis was to identify differences in torque expression between three brands of metallic self-ligating brackets with stainless steel, TMA® and CuNiTi® wire and to compare active and passive designs. 150 of each Damon-3MX (Ormco Inc, Orange, CA, USA), SPEED (Strite Industries, Cambridge, Ontario, Canada) and In-Ovation-R (GAC, Bohemia, NY, USA) brackets were measured for torque expression (Nmm) in an Air-shields Isolette® infant incubator. Torque expression in SPEED and In-Ovation-R brackets began at approximately 7.5° vs. 12° with Damon-3MX. Clinically applicable torque expression (5-20Nmm) was observed from approximately 15-30° in SPEED & In-Ovation-R brackets with stainless steel wire. In Damon-3MX, comparable torsional moments were expressed from 18-30°. With TMA wire, SPEED exerted clinically applicable torsional moments from 18-39°, In-Ovation-R from 21-39° and Damon-3MX from 21-42°. For CuNiTi wire, SPEED expressed torsional moments of 5-20Nmm from 21-72°, In-Ovation-R from 24-63° and Damon-3MX from 27-78°. / Medical Science-Orthodontics

Los Torque teno sus virus (TTSuV) son virus ADN que pertenecen a la familia Anelloviridae y que infectan los cerdos. Son virus con genoma circular, de cadena simple, y hasta hoy se han descrito 4 especies diferentes: TTSuV1a y TTSuV1b, miembros del género Iotatorquevirus, y TTSuV2 y TTSuVk2b, miembros del género Kappatorquevirus. En los últimos años se ha sugerido que los TTSuVs podrían ser agentes que actuarían conjuntamente con otros patógenos y participar como posibles desencadenadores de enfermedad. En concreto, se ha descrito que podrían estar involucrados en la patogenia de enfermedades causadas por circovirus porcino tipo 2 (PCV2). No obstante, este tema continúa siendo controvertido, con lo cual el estudio de la infección por TTSuV en el cerdo se ha convertido en un foco de interés por parte de científicos durante los últimos años. Los estudios descritos en la siguiente tesis van en la línea de estudios previos con el objetivo de contribuir con más argumentos sobre el papel de los TTSuVs en enfermedades porcinas. En el primer estudio se cuantificó la carga viral de TTSuV1 y TTSuV2 en suero de cerdos afectados por dos PCVDs, concretamente el síndrome multisistémico de emaciación post-destete o circovirosis porcina (PMWS) y el síndrome de dermatitis y nefropatía porcino (PDNS). Dicho estudio se llevó a cabo por medio del desarrollo de una nueva técnica de PCR cuantitativa a tiempo real (qPCR). Los resultados de este estudio mostraron que ambos TTSuVs fueron altamente prevalente entre los cerdos estudiados. La carga viral de TTSuV2 fue significativamente mayor en los animales afectados por PMWS, confirmando así la previa asociación sugerida entre este virus y PMWS. Por el contrario, la prevalencia y la carga en suero de TTSuV1 no se relacionaron con la ocurrencia de las PCVDs estudiadas. En el segundo estudio, la prevalencia y la carga viral de los TTSuVs fueron evaluadas en el contexto de una infección experimental con un aislado de virus de la peste porcina clásica (VPPC) de alta virulencia. Las muestras de suero, procedentes de 54 animales, fueron analizadas por medio de una PCR cuantitativa (qPCR) para TTSuV1 y TTSuV2 antes y después (entre 6 y 13 días después) del desafío con el VPPC. Basándose en de la evolución post- infección de la sintomatología clínica y de la respuesta inmune frente el VPPC, los animales se dividieron en dos grupos: grupo I, incluyendo cerdos con una respuesta inmune adecuada contra el VPPC y sin signos clínicos en el día de la necropsia, y el grupo II, sin ninguna respuesta inmune detectable frente a VPPC y presencia de signos clínicos moderados a graves. Los resultados de la cuantificación de los TTSuVs indicaron que la carga viral del TTSuV2 aumentó significativamente después de la exposición con VPPC en el grupo de cerdos con signos clínicos, específicamente en aquellos con un curso moderado de la enfermedad. Esta situación no se dio para TTSuV1. Por tanto, este estudio pone de relieve el comportamiento diferente de ambos TTSuVs, como ya se había visto en el contexto de PMWS, y además apoya la asociación de TTSuV2 con la presentación de enfermedad. En el tercer estudio, las cargas virales y la prevalencia de TTSuV1 y TTSuV2 se evaluaron en muestras de pulmón fijadas en formol y embebidas en parafina (FFPE) que mostraban diferentes tipos de lesiones inflamatorias. Para ello se utilizó una técnica cuantitativa en tiempo real PCR optimizada para su uso en tejidos FFPE. Los resultados demostraron que ambos TTSuVs estaban presentes en el pulmón. Sin embargo, TTSuV2 tuvo mayor carga viral y la prevalencia en todos los grupos estudiados en comparación con TTSuV1. La carga viral media de TTSuV2 también fue mayor en los pulmones con lesiones compatibles con un origen viral en comparación con los pulmones normales o aquellos con evidencia de infecciones causadas por bacterias. Este resultado sugiere un posible papel de TTSuV2 en el mecanismo patogénico de lesiones inflamatorias de los pulmones compatibles con una infección viral. A la luz de estos resultados, y teniendo en cuenta que en el transcurso de las enfermedades estudiadas existen alteraciones significativas del sistema inmunológico, se ha especulado que esta afectación favorezca una mayor capacidad de replicación de TTSuV2. Por tanto, se considera que este virus probablemente es un agente secundario en el contexto de distintas enfermedades que alteran la respuesta inmunitaria. Aparentemente el TTSuV2 sería capaz de causar lesiones pulmonares, aunque leves. / Torque teno sus viruses (TTSuVs) belong to the family Anelloviridae, and are circular, single-stranded DNA viruses infecting pigs. So far, 4 different TTSuV species have been described: TTSuV1a and TTSuV1b members of the genus Iotatorquevirus, and TTSuV2 and TTSuVk2b, members of the genus Kappatorquevirus. In recent years, it has been suggested that TTSuVs could act together with other pathogens and participate as triggering factor for disease occurrence. Specifically, it has been described that they could be involved in the pathogenesis of porcine circovirus type 2 (PCV2) associated diseases (PCVDs). However, this subject remains controversial, thus the study of TTSuV infection in the pig has become a focus of scientific interest in recent years. The studies described in the following thesis go with the same line of previous studies with the aim to contribute with more clues on TTSuVs role in swine disease. In the first study, TTSuV1 and TTSuV2 viral loads were quantified in serum of pigs affected by two PCVDs, postweaning multisystemic wasting syndrome (PMWS) and porcine dermatitis and nephropathy syndrome (PDNS). Such study was carried out by means of a newly developed real-time quantitative PCR (qPCR) method. Results from this study showed that both TTSuVs were highly prevalent among studied pigs. TTSuV2 viral loads were significantly higher in PMWS affected animals, further supporting the previously suggested association between TTSuV2 and PMWS. On the contrary, TTSuV1 prevalence and loads were not related with the occurrence of studied PCVDs. In the second study, TTSuVs prevalence and viral load were assessed in the context of an experimental infection with a highly virulent classical swine fever (CSF) virus (CSFV) isolate. Serum samples from 54 animals were analysed by means of a quantitative PCR (qPCR) for TTSuV1 and TTSuV2 before and after (between 6 and 13 days post-inoculation) the CSFV challenge. Based on the post-infection clinical evolution and immune responses against CSFV, the animals were divided into two groups: group I, with protecting immunity against CSFV and no clinical signs at the day of necropsy, and group II, with no detectable immune responses against CSFV and moderate to severe clinical signs. TTSuVs qPCR results indicated that TTSuV2, but not TTSuV1, load in serum increased significantly after challenge with CSFV in the group of pigs with clinical signs, specifically in those with a moderate course of the disease. Therefore, this study emphasizes the different behaviour of both TTSuVs, as already found in the previous work with PMWS, and further supports the association of TTSuV2 with disease occurrence. In the third study, TTSuV1 and TTSuV2 loads and prevalence were evaluated in formalin-fixed, paraffin-embedded (FFPE) lung samples displaying different types of inflammatory lesions. Such measurements were made by means of a real time quantitative PCR technique optimised for its use on FFPE tissues. Results from the present study demonstrated that both TTSuVs were present in lung. However, TTSuV2 had higher viral load and prevalence in all the studied groups when compared to TTSuV1. TTSuV2 mean load was also higher in lungs with lesions attributed to a viral background when compared to normal lungs or to those with lesions of bacterial origin. This result suggests a possible role of TTSuV2s in the pathogenic mechanism of inflammatory lesions of lungs compatible with viral infection. In light of these results, and taking into account that significant alterations of the immune system are recorded in most of the studied diseases, it has been speculated that TTSuV2 replication up-regulation would be controlled by the immune system. Therefore, it is considered that this virus, but not TTSuV1, is likely a secondary agent in the context of various diseases that alter the immune response. The capabilities of TTSuV2 for causing pulmonary lesions by itself are apparently real, although of low severity.

Thesis (M.Ed.)--Bowling Green State University, 2005. / Document formatted into pages; contains vii, 54 p. : ill. Includes bibliographical references.