Thesis ( Ph.D.). / Written for the Dept. of Physics. Title from title page of PDF (viewed 2009/06/11). Includes bibliographical references.

Thesis (Ph. D.)--University of Toronto, 1996. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 439-493).

Thesis (Ph. D.)--University of Toronto, 1996. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 439-493).

Thesis (Ph. D.)--University of Texas at Austin, 1999. / Vita. Includes bibliographical references (leaves 264-282). Available also in a digital version from Dissertation Abstracts.

Thesis (Ph. D.)--University of Texas at Austin, 2005. / Supervisor: Kathleen Stewart. Vita. Includes bibliographical references.

Thesis (M.F.A.)--Washington State University, May 2010. / Title from PDF title page (viewed on May 14, 2010). "Department of Fine Arts."

Thesis (Ph. D.)--University of Texas at Austin, 1999. / Vita. Includes bibliographical references (leaves 264-282).

O presente estudo propõe-se responder à questão de investigação: como podemos abordar conceitos de geometria plana com estudantes de sexto ano por meio de confecção de objetos manipulativos digitais e não-digitais, permitindo que estes se reconheçam como fabricantes de seu próprio conhecimento? A pesquisa apresenta uma proposta de atividade em que estudantes foram convidados a serem fabricantes de seu próprio conhecimento, mais especificamente de conhecimentos de geometria plana. Por meio da confecção e manipulação de objetos digitais e não-digitais, os estudantes transformaram a sala de aula em uma Fábrica de Matemática. O estudo foi desenvolvido durante o ano de 2016, com uma turma de sexto ano de uma escola municipal de Sapucaia do Sul, no horário regular de aula. Apoiada na teoria do construcionismo de Seymour Papert, na pedagogia da autonomia de Paulo Freire e na aprendizagem cooperativa e por equipes de Jean Piaget, e utilizando o estudo de caso como metodologia, o presente trabalho apresenta uma experiência de abordagem de conceitos de geometria plana – área, perímetro, paralelismo e perpendicularismo, entre outros – que permitiu o reconhecimento, por parte dos estudantes, da possibilidade de se tornarem agentes ativos na construção dos seus conhecimentos. Além disso, percebeu-se quanto aos resultados, que quando lhes são oferecidas diferentes oportunidades para aprendizagem, os estudantes podem se tornar sujeitos críticos, autônomos e produtores de conhecimento. / The present study proposes to answer the research question: how can we approach concepts of flat geometry with sixth-year students by making digital and non-digital manipulative objects, allowing them to recognize themselves as manufacturers of their own knowledge? The research presents a proposal of activity in which students were invited to be manufacturers of their own knowledge, more specifically of knowledge of flat geometry. Through the making and manipulation of digital and non-digital objects, students transformed the classroom into a Mathematics Factory. The study was developed during 2016, with a sixth grade class from a municipal school in Sapucaia do Sul, at regular school hours. Based on the construction theory of Seymour Papert, Paulo Freire 's pedagogy of autonomy and cooperative and team learning by Jean Piaget, and using the case study as methodology, the present work presents an experience of approaching concepts of flat geometry - area, perimeter, parallelism and perpendicularism, among others - that allowed the students to recognize the possibility of becoming active agents in the construction of their knowledge. In addition, it was perceived as to the results, that when they are offered different opportunities for learning, students can become critical, autonomous subjects and producers of knowledge.

Les travaux présentés dans ce manuscrit traitent de l’asservissement visuel d’un éclairage opératoire. Il s’agit d’une thèse CIFRE soutenue par l’entreprise MAQUET SAS et en collaboration avec le Laboratoire PRISME de l’Université d’Orléans. Les éclairages opératoires offrent à l’équipe chirurgicale des conditions d’éclairement suffisantes pour leur permettre d’accomplir leurs gestes. Leur positionnement est difficile en cours d’intervention et engendre fréquemment des heurts entre les membres de l’équipe. Les solutions déjà développées pour résoudre ce problème ne donnent pas satisfaction en raison de l’interaction forte entre le système et l’équipe chirurgicale. Nous proposons dans cette étude un éclairage opératoire asservi visuellement ne nécessitant pas d’information explicite, et opérationnel quel que soit le type de chirurgie. Il s’agit d’un système "intelligent" autrement dit capable de désigner de lui-même la zone où éclairer et "autonome", c’est-à-dire apte à se déplacer seul une fois les coordonnées de la cible connues. Ces deux points constituent la problématique de cette étude. Pour rendre "intelligent" l’éclairage opératoire, nous proposons un processus de désignation basé sur la reconnaissance d’objets spécifiques : le sang, la peau, les champs stériles et les instruments. Pour ce faire nous utilisons une fusion des attributs forme, couleur et mouvement basée sur le cadre crédibiliste. Nous résolvons les problèmes d’inhomogénéité de l’image dus à la puissance de l’éclairement par l’ajout d’une étape de fusion intermédiaire. Une fois l’ensemble des objets reconnus, nous procédons à la désignation de la zone à éclairer à l’aide de la théorie de la décision. L’autonomie du système est quant à elle assurée par une boucle d’asservissement visuel 2D, qui permet de faire converger l’éclairage vers la zone précédemment désignée. Nous avons réalisé au cours de cette étude un prototype quia permis de valider l’approche dans des conditions réelles. / The work presented in this manuscript is related to the visual servoing of a surgical light. This is a collaborative study between MAQUET SAS and PRISM laboratory (University of Orléans). Surgical light provides the surgical team enough lighting to perform their activities. The positioning of this equipment during the operation is arduous and leads frequently to disagreement between members of the team. Solutions already developed to solve this problem do not offer satisfaction in reason of the high interaction between the system and the team. This work aims to propose a surgical light visually served which do not require explicit information and which is operational whatever the kind of surgery. It consists in an "intelligent" system able to designate by itself the region where the surgeon is working on, and which is also "autonomous", that is to say the system can move to this target. These two points correspond to the problematic of this study. To make the operating light "intelligent" we propose an architecture based on the recognition of specific objects : blood, skin, steriled field, instruments. To achieve this we fuse shape, color and movement attributes. We solve the inhomogeneity problem of images due to high illumination thanks to an intermediate fusion step. Once all the objects are recognized we carry out the designation thanks to the decision theory. The "autonomous" part of the system consists in a 2D visual servoing loop that makes possible the convergence of the surgical light to the region of interest. A prototype has been realized during this work, which enabled us to validate the proposed approach in a real environment.

Um dos problemas técnicos que ocorrem nos revestimentos cerâmicos é a possibilidade de duas peças serem da mesma cor sob a luz do dia, mas de cores diferentes sob outra iluminação. Tal fenômeno é chamado metamerismo. O presente trabalho teve como objetivo realizar um estudo sobre a influência de variáveis do processo de fabricação de revestimentos cerâmicos na ocorrência do fenômeno de metamerismo, tendo como objeto de estudo uma peça monoporosa de esmalte branco-brilhante, e um porcelanato mate. Para tanto, avaliou-se o efeito da variação de iluminante, correlacionado com as seguintes características dos revestimentos cerâmicos investigados: i) tipologia de esmalte; ii) base, engobe esmaltes; iii) variação de camada; iv) utilização de quartzo, caulim e zirconita; v) variação de corantes. Os resultados mostraram que esmaltes, como o branco-brilhante, se destacam no aparecimento da característica metamérica, tanto mais quanto mais espessa a camada. Já, quando se aumenta a camada do mate, este fenômeno ameniza. A zirconita, por ser um opacificante, ameniza a reflexão da luz, gerando uma diminuição do metamerismo. O quartzo promove o metamerismo, já que influencia no aparecimento do brilho. Quanto aos corantes, pigmentos que amenizam o reflexo da luz, como o preto e cinza, possuem um valor metamérico baixo, já pigmentos que tendem ao reflexo maior da luz, promovem o metamerismo. Com base nisso, o suporte do porcelanato esmaltado que se apresenta em uma base cinza, possui um valor metamérico menor que a base da monoporosa, que possui uma cor bege. Ficou evidenciada a influência das curvas espectrais e do reflexo no aparecimento do metamerismo, podendo ser um ponto crucial para que empresas trabalhem em cima deste problema, a fim de ser um diferencial para seus clientes no mercado competitivo como o de hoje. / One of several problems that occur in ceramic tiles, is the possibility that two objects are the same color in the light of day, but of different colors in a different light. This phenomenon, in which two colors are similar under a light source but different under another, is called metamerism. Seeking a study on this phenomenon was analyzed the influence of some variables on the metamerism in a white enamel-bright monoporosity, and a matte porcelain. Some of the variables selected for the study of the influence of the media, and enamel on engobe metamerism, the addition of opacifier material, in suspension and bright enamels in different percentages, the analysis with the addition of pure colors and mixtures of the same in glazes; variations in the enamel layer, among other factors. Before, it was noticed that the enamel provide a high spectral curve, ie, materials that reflect the highly light, tend to influence the onset of this phenomenon. Thus, materials that influence the formation of brightness as quartz help this phenomenon to emerge since opacifying materials that have the feature to break it brightness, ie, which have lower spectral curves, decreases the appearance of this phenomenon. In the matter of color is the same as explained above, ie, pigments that mitigate the reflection of light as the black and gray, have a low value metameric because colors tend to reflect more light, raise this value. On this basis, the support of porcelain enamel that comes in on a gray metameric has a value less than the base of monoporosity, which has a beige color. Having knowledge of these factors, it is clear the influence of spectral curves and reflex formed by these variables in the emergence of this phenomenon and may be a crucial point for companies to work upon this problem, in order to be a differentiator for its customers in competitive market which is today.