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Applications of Structure-from-Motion Photogrammetry to Fluvial GeomorphologyDietrich, James 14 January 2015 (has links)
Since 2011, Structure-from-Motion Multi-View Stereo Photogrammetry (SfM or SfM-MVS) has gone from an overlooked computer vision technique to an emerging methodology for collecting low-cost, high spatial resolution three-dimensional data for topographic or surface modeling in many academic fields. This dissertation examines the applications of SfM to the field of fluvial geomorphology. My research objectives for this dissertation were to determine the error and uncertainty that are inherent in SfM datasets, the use of SfM to map and monitor geomorphic change in a small river restoration project, and the use of SfM to map and extract data to examine multi-scale geomorphic patterns for 32 kilometers of the Middle Fork John Day River. SfM provides extremely consistent results, although there are systematic errors that result from certain survey patterns that need to be accounted for in future applications. Monitoring change on small restoration stream channels with SfM gave a more complete spatial perspective than traditional cross sections on small-scale geomorphic change. Helicopter-based SfM was an excellent platform for low-cost, large scale fluvial remote sensing, and the data extracted from the imagery provided multi-scalar perspectives of downstream patterns of channel morphology. This dissertation makes many recommendations for better and more efficient SfM surveys at all of the spatial scales surveyed. By implementing the improvements laid out here and by other authors, SfM will be a powerful tool that will make 3D data collection more accessible to the wider geomorphic community.
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Synthèse de vues pour l’initialisation de pose / Viewpoint synthesis for pose initialisationRolin, Pierre 08 March 2017 (has links)
La localisation est un problème récurrent de la vision par ordinateur, avec des applications dans des domaines multiples tels que la robotique ou la réalité augmentée. Dans cette thèse on considère en particulier le problème d'initialisation de la pose, c'est-à-dire la localisation sans information a priori sur la position de la caméra. Nous nous intéressons à la localisation à partir d'une image monoculaire et d'un nuage de points reconstruit à partir d'une séquence d'images. Puisque nous n'avons pas d'a priori sur la position de la caméra, l'estimation de la pose s'appuie sur la recherche de correspondances entre des points de l'image et des points du modèle de la scène. Cette mise en correspondance est difficile en raison de sa combinatoire élevée. Elle peut être mise en défaut lorsque l'image dont on cherche la pose est très différente de celles ayant servi à la construction du modèle, en particulier en présence de forts changements de point de vue. Cette thèse développe une approche permettant la mise en correspondance image-modèle dans ces situations complexes. Elle consiste à synthétiser localement l'apparence de la scène à partir de points de vue virtuels puis à ajouter au modèle des descripteurs extraits des images synthétisées. Comme le modèle de scène est un nuage de points, la synthèse n'est pas faite par rendu 3D mais utilise des transformations 2D locales des observations connues de la scène. Les contributions suivantes sont apportées. Nous étudions différents modèles de transformation possibles et montrons que la synthèse par homographie est la plus adaptée pour ce type d'application. Nous définissons une méthode de positionnement des points de vue virtuels par rapport à une segmentation de la scène en patchs plans. Nous assurons l'efficacité de l'approche proposée en ne synthétisant que des vues utiles : elles sont éloignées de celles existantes et elles ne se recouvrent pas. Nous vérifions également que la scène est visible à partir des points des vue virtuels pour ne pas produire des vues aberrantes à cause d’occultations. Enfin, nous proposons une méthode de recherche de correspondances image-modèle qui est à la fois rapide et robuste. Cette méthode exploite la répartition non-uniforme des correspondances correctes dans le modèle, ce qui permet de guider leur recherche. Les résultats expérimentaux montrent que la méthode proposée permet de calculer des poses dans des configurations défavorables où les approches standard échouent. De façon générale la précision des poses obtenues augmente significativement lorsque la synthèse de vue est utilisée. Enfin nous montrons que, en facilitant la mise en correspondance image-modèle, cette méthode accélère le calcul de pose / Localisation is a central problem of computer vision which has numerous applications such as robotics or augmented reality. In this thesis we consider the problem of pose initialisation, which is pose computation without prior knowledge on the camera position. We are interested in pose computation from a single image and a point cloud that has been reconstructed from a set of images. As we do not have prior knowledge on the camera position, pose estimation entirely rely on finding correspondences between the image and the model. The search for these correspondences is a difficult problem because of its high combinatorial complexity. It can fail if the image is very different from the ones we used to construct the model, in particular when there is a large viewpoint change between them. This thesis proposes an approach to make matching possible in such difficult scenarios. It consists in synthesising locally the appearance of the scene from virtual viewpoints and add descriptors extracted from these synthetic views to the model. Because the scene model is a point cloud, the synthesis is not a 3D rendering but a local 2D transform of existing observations of the scene. The following contributions have been proposed. We study different transform models and show that homographic transformations are the best suited for this application. We define a method to position the virtual viewpoints with respect to a planar segmentation of the scene model. We ensure time efficiency by only synthesising useful views, i.e. views that are far from the existing one and don't overlap. Furthermore we verify that the synthesized surface is visible from the virtual viewpoint to avoid producing aberrant views due to occlusions. Finally, we propose a robust and time efficient method to research image-model correspondences. It uses geometric cues in a guided matching framework to efficiently identify sets of correct correspondences. Experimental results show that the proposed approach makes possible pose computation in situation where standard methods fail. In general the precision and repeatability of computed poses is significantly improved by the use of view synthesis. We also show that it also reduce the pose computation times by making image-model matching easier
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Religionsfilosofins uppgift i en senmodern, mångreligiös och pluralistisk världSchulze, Jennifer January 2019 (has links)
We live in a so-called late-modern age where religion and various world-views are something one must relate to in society, no matter what one thinks of that and wherever one lives in the world. This statement applies not least if we are to be able to live in consensus with each other and if we want a world with fewer conflicts, which I, without any evidence, claim that the majority of the world´s population wants. The fact that people with different truth claims, religions an world-views live side by side as today, is not a new phomenon globally and historically, but the Christian conformity that was formerly the practice in the West has today been replaced by a multitude of world-views through increased immigration and through increased secularization. The purpose of this thesis is to investigate and describe the mission of religious philosophy in a late-modern, multi-religious, pluralistic world. And in the first place to find out what the three religious philosophers Kevin Schilbrack from USA, Mikael Stenmark from Sweden and Nick Trakakis from Australia say about this. By comparing their perceptions with each other, I want to point out similarities and differences and see why I mean that the discipline should be developed for one or the other direction. I advocate that religion of philosophy continues to work with the methods by which one seeks to understand, describe and explain different religions ans world-views, as well as critically review, assess or evaluate them. This is because the philosophy of religion is to be taken seriously in order for philosophy of religion to take society seriously. Religion of philosophy should also study lived religion as a complement to the textculture. Moving the starting point to the religion you are studying can also be of benefit to the study of religious philosophy in order to get a more accurate picture of foreign religions. The advantage of what I advocate here is that in the future we can get a philosophy of religion that is not normative, defined that it has the starting point in theism, that the confessional is the norm, or relativistic.
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Modelisation Visuelle d'un Objet Inconnu par un Robot Humanoide Autonome / Visual Modeling of an Unknown Object by an Autonomous Humanoid RobotFoissotte, Torea 03 December 2010 (has links)
Ce travail est focalisé sur le problème de la construction autonome du modèle 3D d'un objet inconnu en utilisant un robot humanoïde. Plus particulièrement, nous considérons un HRP-2 guidé par la vision au sein d'un environnement connu qui peut contenir des obstacles. Notre méthode considère les informations visuelles disponibles, les contraintes sur le corps du robot ainsi que le modèle de l'environnement dans le but de générer des postures adéquates et les mouvements nécessaires autour de l'objet. Le problème de sélection de vue ("Next-Best-View") est abordé en se basant sur un générateur de postures qui calcule une configuration par la résolution d'un problème d'optimisation. Une première solution est une approche locale où un algorithme de rendu original à été conçu afin d'être inclut directement dans le générateur de postures. Une deuxième solution augmente la robustesse aux minimums locaux en décomposant le problème en 2 étapes: (i) trouver la pose du capteur tout en satisfaisant un ensemble de contraintes réduit, et (ii) calculer la configuration complète du robot avec le générateur de posture. La première étape repose sur des méthodes d'optimisation globale et locale (BOBYQA) afin de converger vers des points de vue pertinents dans des espaces de configuration admissibles non convexes. Notre approche est testée en conditions réelles par le biais d'une architecture cohérente qui inclus différents composants logiciels spécifique à l'usage d'un humanoïde. Ces expériences intègrent des travaux de recherche en cours en planification de mouvements, contrôle de mouvements et traitement d'image, qui pourront permettre de construire de façon autonome le modèle 3D d'un objet. / This work addresses the problem of autonomously constructing the 3D model of an unknown object using a humanoid robot.More specifically, we consider a HRP-2 evolving in a known environment, which is possibly cluttered, guided by vision.Our method considers the visual information available, the constraints on the robot body, and the model of the environment in order to generate pertinent postures and the necessary motions around the object.Our two solutions to the Next-Best-View problem are based on a specific posture generator, where a posture is computed by solving an optimization problem.The first solution is a local approach to the problem where an original rendering algorithm is specifically designed in order to be directly included in the posture generator. The rendering algorithm can display complex 3D shapes while taking into account self-occlusions.The second solution seeks more global solutions by decoupling the problem in two steps: (i) find the best sensor pose while satisfying a reduced set of constraints on the humanoid, and (ii) generate a whole-body posture with the posture generator.The first step relies on global sampling and BOBYQA, a derivative-free optimization method, to converge toward pertinent viewpoints in non-convex feasible configuration spaces.Our approach is tested in real conditions by using a coherent architecture that includes various complex software components that consider the specificities of the humanoid robot. This experiment integrates on-going works addressing the tasks of motion planning, motion control, and visual processing, to allow the completion of the 3D object reconstruction in future works.
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O Grupo Multifamília no contexto de vulnerabilidade social: o olhar do profissional / "The Multifamily Group in the context of social vulnerability: the professional view"Oliveira, Sonia Maria de 14 May 2012 (has links)
Made available in DSpace on 2016-04-28T20:38:08Z (GMT). No. of bitstreams: 1
Sonia Maria de Oliveira.pdf: 746163 bytes, checksum: a3ac726e3f37ff1ee16a453d14c056b8 (MD5)
Previous issue date: 2012-05-14 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In order to know and understand the professional experience with the Multifamily
Group undertaken in the context of social vulnerability, this research attempted to
investigate what is the view of the professional to his group: its composition, the
theories and techniques, which use the learning achieved in the relation with the
families and what s the influence of the institutional context in the development of his
group. Empirical research, of qualitative approach, exploratory descriptive type, used
semi structured interviews to collect data. The participants were 05 professional
coordinators of Multifamily Group, identified by the criteria of intentional sample. The
analysis has been done with a few tools of the qualitative method of Analysis of the
Content and the interpretation of the results was based on the theoretical principles
of systemic thinking and the new paradigmatic and in the specific literature on the
Multifamily Group. The results showed that the prepared professional for such work,
should have the needed flexibility to adapt the group to the requirements of the
context, without, however, moving away from the defining premises of this practice.
His function in the group permeates different tasks; not being possible to adopt a
single name to characterize it. The professional performance should preferably be
interdisciplinary, backed by legitimated spaces for reflection with other professionals
in order to keep a sensitive action to the constructions that may emerge from
meetings / Com o objetivo de conhecer e compreender a experiência do profissional com o
Grupo Multifamília realizado no contexto de vulnerabilidade social, essa pesquisa
procurou investigar qual é o olhar do profissional para o seu grupo: sua composição;
as teorias e técnicas que utiliza; as aprendizagens alcançadas na relação com as
famílias e qual a influência do contexto institucional no desenvolvimento de seu
grupo. Pesquisa empírica, de abordagem qualitativa, de tipo exploratório descritivo,
utilizou a entrevista semi-estruturada para coleta de dados. Os participantes foram
05 profissionais coordenadores de Grupo Multifamília, identificados pelo critério de
amostra intencional. A análise foi feita com algumas ferramentas qualitativas do
método de Análise de Conteúdo e a interpretação dos resultados foi embasada nos
pressupostos teóricos do pensamento sistêmico novo paradigmático e na literatura
específica sobre o Grupo Multifamília. Os resultados mostraram que o profissional
preparado para esse trabalho, deve ter a flexibilidade necessária para adaptar o
grupo às necessidades do contexto, sem, contudo, se afastar dos pressupostos
definidores dessa prática. Sua função no grupo perpassa diferentes tarefas, não
sendo possível adotar um único nome para caracterizá-la. Sua atuação deve ser
preferencialmente interdisciplinar, respaldada por espaços legítimos para reflexão
com outros profissionais, a fim de manter uma atuação sensível às construções que
emergirem dos encontros
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The spatiotemporal dynamics of visual attention during real-world event perceptionRinger, Ryan January 1900 (has links)
Doctor of Philosophy / Department of Psychological Sciences / Lester Loschky / Everyday event perception requires us to perceive a nearly constant stream of dynamic information. Although we perceive these events as being continuous, there is ample evidence that we “chunk” our experiences into manageable bits (Zacks & Swallow, 2007). These chunks can occur at fine and coarse grains, with fine event segments being nested within coarse-grained segments. Individual differences in boundary detection are important predictors for subsequent memory encoding and retrieval and are relevant to both normative and pathological spectra of cognition. However, the nature of attention in relation to event structure is not yet well understood. Attention is the process which suppresses irrelevant information while facilitating the extraction of relevant information. Though attentional changes are known to occur around event boundaries, it is still not well understood when and where these changes occur. A newly developed method for measuring attention, the Gaze-Contingent Useful Field of View Task (GC-UFOV; Gaspar et al., 2016; Ringer, Throneburg, Johnson, Kramer, & Loschky, 2016; Ward et al., 2018) provides a means of measuring attention across the visual field (a) in simulated real-world environments and (b) independent of eccentricity-dependent visual constraints. To measure attention, participants performed the GC-UFOV task while watching pre-segmented videos of everyday activities (Eisenberg & Zacks, 2016; Sargent et al., 2013). Attention was probed from 4 seconds prior to 6 seconds after coarse, fine, and non-event boundaries. Afterward, participants’ memories for objects and event order were tested, followed by event segmentation. Attention was predicted to either become impaired (attentional impairment hypothesis), or it was predicted to be broadly distributed at event boundaries and narrowed at event middles (the ambient-to-focal shift hypothesis). The results showed marginal evidence for both attentional impairment and ambient-to-focal shift hypotheses, however model fitness was equal for both models. The results of this study were then used to develop a proposed program of research to further explore the nature of attention during event perception, as well as the ability of these two hypotheses to explain the relationship between attention and memory during real-world event perception.
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The impact of FNGO services on the performance of micro and small enterprises : empirical evidence from the Volta Region, GhanaAtiase, Victor Yawo January 2018 (has links)
Financial Non-Governmental Organisations (FNGOs) are regulated microfinance institutions (MFIs) that operate with the social welfare logic in the delivery of Microcredit (MC) and Entrepreneurship Training (ET) to the poor in Ghana. The provision of these two capitals (MC and ET) is aimed at supporting the poor to create sustainable Micro and Small Enterprises (MSEs) which is aimed at generating both skilled and unskilled employment. The major aim of this study is to investigate the impact of MC and ET delivered by FNGOs on the performance of MSEs in Ghana. Theoretically, the study adopts both the Institutional Theory and the Resource-Based View theory as the underlying theoretical frameworks, assuming that institutional and resource factors have a great influence on FNGOs in their delivery of MC and ET to MSEs in Ghana. The research design adopted in undertaking this study is based on the pragmatic research philosophy. Specifically, the mixed strategy with an explanatory triangulation method has been used. The mixed method has been adopted purposely for model testing as well as for exploring various issues on FNGOs and their role in the performance of MSEs. Primary data were collected through a quantitative method using a survey as well as through qualitative interviews. Adopting a stratified random sampling method, a total of 720 self-administered questionnaires were sent out in March 2017 to MSEs in the Volta Region of Ghana to collect primary data. Out of the number sent, 506 questionnaires were retrieved generating a response rate of 70.2%. Also, interviews were conducted with 10 MSEs. A multiple regression model was applied in measuring the impact of MC and ET on the performance of MSEs. The findings suggest that firm characteristics such as gender, managers educational level, industry category and business age correlate positively with employment sales and profitability growth which are statistically significant at 1% level. Secondly, the study also found that both MC and ET factors have a significant impact on MSE performance in the areas of employment, sales and profitability at 1% significant level. The qualitative findings also support the model tested in this study in the sense that the combined approach of both MC and ET have a significant impact on MSE performance in Ghana. This study has made two main contributions. Firstly, the provision of MC by FNGOs can only have the desired impact on the performance of MSEs if it is combined with entrepreneurship training, thereby leading to a sustainable employment, sales and profitability growth. Therefore, by using the 506 MSEs financed by FNGOs in the Volta region of Ghana, this study has for the first time in the Ghanaian microfinance landscape tested an empirical model and came out with meaningful findings for effective integration of ET into microfinance to improve the delivery of financial services to MSEs in Ghana by FNGOs and other socially oriented MFIs. The study has therefore developed a practical framework for ensuring that ET is provided alongside the delivery of MC in order to have the desired impact on the performance of MSEs. The study provided implications for policy and practice for making MC and ET more accessible to MSEs to achieve the desired goal of creating employment. Secondly, even though FNGOs play a very important role in providing entrepreneurial finance to MSEs particularly in developing countries, it has received insufficient research attention. This study has, therefore, added to the scanty research available about FNGOs and their contribution to entrepreneurship development and poverty reduction in developing countries.
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Olhar em primeira pessoa: uso contemporâneo da câmera subjetiva no cinema de ficção / -Oliveira, Rodrigo Campos de 04 October 2016 (has links)
A câmera subjetiva abrange o ponto de vista, em suas múltiplas implicações narrativas, enunciativas, audiovisuais. À sua crescente presença no audiovisual contemporâneo correspondem expansões de seus sentidos comumente relacionados à linguagem clássica narrativa cinematográfica e a uma normatividade que restringe seu uso sistemático. Novos usos da câmera subjetiva associam novos fatores e novas funções dentro do cinema, relacionando técnicas e tecnologias com resultados estéticos. Esta pesquisa investiga a câmera subjetiva como recurso de linguagem e de estilo audiovisual que movimenta variáveis entre a espectatorialidade e o filme. / Subjective camera embraces point of view, in several narrative, enunciative and audiovisual implications. The sense commonly related to classical cinema narrative language becomes expanded with new approaches of subjective camera in contemporary works, breaking the rules that restrain its systematic utilization. New usage of subjective camera links new functions and new elements inside cinema, connecting technologies and technics with aesthetics results. This research examines subjective camera as an audiovisual stylistic feature that crosses film language and spectatorship.
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Aprendizado de máquina parcialmente supervisionado multidescrição para realimentação de relevância em recuperação de informação na WEB / Partially supervised multi-view machine learning for relevance feedback in WEB information retrievalSoares, Matheus Victor Brum 28 May 2009 (has links)
Atualmente, o meio mais comum de busca de informações é a WEB. Assim, é importante procurar métodos eficientes para recuperar essa informação. As máquinas de busca na WEB usualmente utilizam palavras-chaves para expressar uma busca. Porém, não é trivial caracterizar a informação desejada. Usuários diferentes com necessidades diferentes podem estar interessados em informações relacionadas, mas distintas, ao realizar a mesma busca. O processo de realimentação de relevância torna possível a participação ativa do usuário no processo de busca. A idéia geral desse processo consiste em, após o usuário realizar uma busca na WEB permitir que indique, dentre os sites encontrados, quais deles considera relevantes e não relevantes. A opinião do usuário pode então ser considerada para reordenar os dados, de forma que os sites relevantes para o usuário sejam retornados mais facilmente. Nesse contexto, e considerando que, na grande maioria dos casos, uma consulta retorna um número muito grande de sites WEB que a satisfazem, das quais o usuário é responsável por indicar um pequeno número de sites relevantes e não relevantes, tem-se o cenário ideal para utilizar aprendizado parcialmente supervisionado, pois essa classe de algoritmos de aprendizado requer um número pequeno de exemplos rotulados e um grande número de exemplos não-rotulados. Assim, partindo da hipótese que a utilização de aprendizado parcialmente supervisionado é apropriada para induzir um classificador que pode ser utilizado como um filtro de realimentação de relevância para buscas na WEB, o objetivo deste trabalho consiste em explorar algoritmos de aprendizado parcialmente supervisionado, mais especificamente, aqueles que utilizam multidescrição de dados, para auxiliar na recuperação de sites na WEB. Para avaliar esta hipótese foi projetada e desenvolvida uma ferramenta denominada C-SEARCH que realiza esta reordenação dos sites a partir da indicação do usuário. Experimentos mostram que, em casos que buscas genéricas, que o resultado possui um bom diferencial entre sites relevantes e irrelevantes, o sistema consegue obter melhores resultados para o usuário / As nowadays the WEB is the most common source of information, it is very important to find reliable and efficient methods to retrieve this information. However, the WEB is a highly volatile and heterogeneous information source, thus keyword based querying may not be the best approach when few information is given. This is due to the fact that different users with different needs may want distinct information, although related to the same keyword query. The process of relevance feedback makes it possible for the user to interact actively with the search engine. The main idea is that after performing an initial search in the WEB, the process enables the user to indicate, among the retrieved sites, a small number of the ones considered relevant or irrelevant according with his/her required information. The users preferences can then be used to rearrange sites returned in the initial search, so that relevant sites are ranked first. As in most cases a search returns a large amount of WEB sites which fits the keyword query, this is an ideal situation to use partially supervised machine learning algorithms. This kind of learning algorithms require a small number of labeled examples, and a large number of unlabeled examples. Thus, based on the assumption that the use of partially supervised learning is appropriate to induce a classifier that can be used as a filter for relevance feedback in WEB information retrieval, the aim of this work is to explore the use of a partially supervised machine learning algorithm, more specifically, one that uses multi-description data, in order to assist the WEB search. To this end, a computational tool called C-SEARCH, which performs the reordering of the searched results using the users feedback, has been implemented. Experimental results show that in cases where the keyword query is generic and there is a clear distinction between relevant and irrelevant sites, which is recognized by the user, the system can achieve good results
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Reificação na ficção científica norte-americana dos anos 60: uma análise do foco narrativo de Do Androids dream of electric sheep? de Philip K. Dick / Reification in the American science fiction of the 60th: an analysis of the narrative focus of do androids dream of eletric sheep? by Philip K. DickPiacentini, Gustavo 28 April 2011 (has links)
Esta dissertação busca investigar os materiais sócio-históricos dos anos 60 norte-americanos materializados no romance de ficção científica Do androids dream of electric sheep? de Philip K. Dick por meio da análise do foco narrativo, especialmente. Embora não seja considerado um dos mais refinados romances de Dick, a obra apresenta um diagnóstico bastante apurado dos limites de experiência disponíveis da década. / This dissertation aims to investigate the socio-historical materials of the North American 60s materialized in the Philip K. Dicks science fiction novel Do androids dream of electric sheep? by analyzing its point of view, mostly. Although it is not considered one of Dicks finest novels, the work presents a very refined diagnosis of the limits of the available experiences of the decade.
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