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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Local analytic and global convex methods for the 3D reconstruction of isometric deformable surfaces. / Méthodes Analytiques Locales et Méthodes Globales Convexes pour la Reconstruction 3D de Surfaces Isométriquement Déformables.

Chhatkuli, Ajad 02 December 2016 (has links)
Cette thèse contribue au problème de la reconstruction 3D pour les surfaces déformables avec une seule caméra. Afin de modéliser la déformation de la surface, nous considérons l’isométrie puisque de nombreuses déformations d’objets réels sont quasi-isométriques. L’isométrie implique que, lors de sa déformation, la surface ne peut pas être étirée ou compressée. Nous étudions deux problèmes. Le premier est le problème basé sur une modèle 3D de référence et une seule image. L’état de l’art propose une méthode locale et analytique de calcul direct de profondeur sous l’hypothèse d’isométrie. Dans cette méthode, la solution pour le gradient de la profondeur n’est pas utilisée. Nous prouvons que cette méthode s’avère instable lorsque la géométrie de la caméra tend à être affine. Nous fournissons des méthodes alternatives basées sur les solutions analytiques locales des quantités de premier ordre, telles que les gradients de profondeur ou les normales de la surface. Nos méthodes sont stables dans toutes les géométries de projection. Dans le deuxième type de problème de reconstruction sans modèle 3D de référence, on obtient les formes de l’objet à partir d’un ensemble d’images où il apparaît déformé. Nous fournissons des solutions locales et globales basées sur le modéle de la caméra perspective. Dans la méthode locale ou par point, nous résolvons pour la normale de la surface en chaque point en supposant que la surface est infinitésimalement plane. Nous calculons ensuite la surface par intégration. Dans la méthode globale, nous trouvons une relaxation convexe du problème. Celle-ci est basée sur la relaxation de l’isométrie en contrainte d’inextensibilité et sur la maximisation de la profondeur en chaque point de la surface. Cette solution combine toutes les contraintes en un seul programme d’optimisation convexe qui calcule la profondeur et utilise une représentation éparse de la surface. Nous détaillons les expériences approfondies qui ont été réalisées pour démontrer l’efficacité de chacune des méthodes. Les expériences montrent que notre solution libre de modèle de référence local fonctionne mieux que la plupart des méthodes précédentes. Notre méthode local avec un modèle 3D de référence et notre méthode globale sans modèle 3D apportent de meilleurs résultats que les méthodes de l’état de l’art en étant robuste au bruit de la correspondance. En particulier, nous sommes en mesure de reconstruire des déformations complexes, non-lisses et d’articulations avec la seconde méthode; alors qu’avec la première, nous pouvons reconstruire avec précision de déformations larges à partir d’images prises avec des très longues focales. / This thesis contributes to the problem of 3D reconstruction for deformable surfaces using a single camera. In order to model surface deformation, we use the isometric prior because many real object deformations are near-isometric. Isometry implies that the surface cannot stretch or compress. We tackle two different problems. The first is called Shape-from-Template where the object’s deformed shape is computed from a single image and a texture-mapped 3D template of the object surface. Previous methods propose a differential model of the problem and compute the local analytic solutions. In the methods the solution related to the depth-gradient is discarded and only the depth solution is used. We demonstrate that the depth solution lacks stability as the projection geometry tends to affine. We provide alternative methods based on the local analytic solutions of first-order quantities, such as the depth-gradient or surface normals. Our methods are stable in all projection geometries. The second type of problem, called Non-Rigid Shape-from-Motion is the more general templatefree reconstruction scenario. In this case one obtains the object’s shapes from a set of images where it appears deformed. We contribute to this problem for both local and global solutions using the perspective camera. In the local or point-wise method, we solve for the surface normal at each point assuming infinitesimal planarity of the surface. We then compute the surface by integration. In the global method we find a convex relaxation of the problem. This is based on relaxing isometry to inextensibility and maximizing the surface’s average depth. This solution combines all constraints into a single convex optimization program to compute depth and works for a sparse point representation of the surface. We detail the extensive experiments that were used to demonstrate the effectiveness of each of the proposed methods. The experiments show that our local template-free solution performs better than most of the previous methods. Our local template-based method and our global template-free method performs better than the state-of-the-art methods with robustness to correspondence noise. In particular, we are able to reconstruct difficult, non-smooth and articulating deformations with the latter; while with the former we can accurately reconstruct large deformations with images taken at very long focal lengths.
72

Dermatofibrosarcoma Protuberans of the Face: Surgical Management

Simman, Richard, Defranzo, Anthony, Sanger, Claire, Thompson, James 01 May 2005 (has links)
Dermatofibrosarcoma protuberans (DFSP) is a locally aggressive, rarely metastatic, spindle cell tumor. It is most commonly found on the trunk and rarely on the head and neck. Recurrence has been found to be more common in the head and neck region, which may be attributable to delayed patient presentation or a reluctance for wide excision in that region. The authors report a rare case of DFSP presenting as a large mass of the face. Surgical treatment required aggressive local resection of the tumor, including the underlying maxillary antrum. The soft tissue was cleared by Mohs technique. More than one procedure was required to obtain clear bone margins. Adjuvant radiation therapy was used to gain local control. Reconstruction was performed using a cheek advancement flap, as well as a forehead flap and split-thickness graft to the donor site.
73

A General Diffusion of Knowledge: Republican Efforts to Build a Public School System in Reconstruction Texas

Hathcock, James A. 12 1900 (has links)
From the early days as a Spanish colony Texas attracted settlers with the promise of cheap fertile land. During the period of Mexican control the population of Texas increased and a desire for public education manifested among the people. Through the end of the Civil War government in Texas never provided an adequate means for educating the children of the region. Even when funds became available with the Compromise of 1850 the state only established a school fund to help offset the costs of education, but did not provide a public school system. The first truly successful attempt at mass education in Texas came after the Civil War with the work of the Freedmen’s Bureau. The bureau helped the former slaves adjust to the emerging post war society through a variety of means such as education. In spite of its short existence the bureau managed to educate thousands of African Americans. By 1870 the former slaves wanted more education for their children, and Texans of all races began to see the need for a public school system. This study focuses on Republican efforts during Reconstruction to establish a public school system in Texas to meet the educational needs of its children. An analysis of data from county, state, and federal records forms the basis of this study. The data suggests that Republican efforts were hampered by the opposition of Texans to high taxes, compulsory education, racism, and animosity toward that party for emancipation and Civil War.
74

Viniční hospodářství Bukovský / " Bukovsky Winery"

Šejk, Sanko January 2010 (has links)
It is reconstruction and extension of a threefloor building of a winery in the center of village Kobyli. The proposal consists of expansion of capacity of wine production and storage. It is making spaces for presentation od the winery and a larger conference space. In the third floor there are nine rooms with own bathroom each. With capacity for 20 persons.
75

Post-War Peacebuilding Reviewed: A Critical Exploration of Generic Approaches to Post-War Reconstruction

Llamazares, Monica January 2005 (has links)
Yes / Peacebuilding, as a remedy for all the ailments afflicting any society emerging from war, has placed this complex and overloaded concept at the centre of a growing network of actors engaged in its formulation and implementation. This paper critically examines the implications of a growing convergence in definitions and approaches amongst this `international post-war peacebuilding community'.
76

Ordinal and convex assumptions in phylogenetic tree reconstruction

Candy, Robin January 2014 (has links)
Phylogenetics is a field primarily concerned with the reconstruction of the evolutionary history of present day species. Evolutionary history is often modeled by a phylogenetic tree, similar to a family tree. To recreate a phylogenetic tree from information about current species, one needs to make assumptions about the evolutionary process. These assumptions can range from full parametrised models of evolution to simple observations. This thesis looks at the reconstruction of phylogenetic trees under two different assumptions. The first, known as the ordinal assumption, has been previously studied and asserts that as species evolve, they become more dissimilar. The second, the convex assumption, has not previously been studied in this context and asserts that changes species go through to become dissimilar are progressively larger than the current differences between those species. This thesis presents an overview of mathematical results in tree reconstruction from dissimilarity maps (also known as distance matrices) and develops techniques for reasoning about the ordinal and convex assumptions. In particular, three main results are presented: a complete classification of phylogenetic trees with four leaves under the ordinal assumption; a partial classification of phylogenetic trees with four leaves under the convex assumption; and, an independent proof of a result on the relationship between ultrametrics and the ordinal assumption.
77

Topological reconstruction and compactification theory

Pitz, Max F. January 2015 (has links)
This thesis investigates the topological reconstruction problem, which is inspired by the reconstruction conjecture in graph theory. We ask how much information about a topological space can be recovered from the homeomorphism types of its point-complement subspaces. If the whole space can be recovered up to homeomorphism, it is called reconstructible. In the first part of this thesis, we investigate under which conditions compact spaces are reconstructible. It is shown that a non-reconstructible compact metrizable space must contain a dense collection of 1-point components. In particular, all metrizable continua are reconstructible. On the other hand, any first-countable compactification of countably many copies of the Cantor set is non-reconstructible, and so are all compact metrizable h-homogeneous spaces with a dense collection of 1-point components. We then investigate which non-compact locally compact spaces are reconstructible. Our main technical result is a framework for the reconstruction of spaces with a maximal finite compactification. We show that Euclidean spaces &reals;<sup>n</sup> and all ordinals are reconstructible. In the second part, we show that it is independent of ZFC whether the Stone-&Ccaron;ech remainder of the integers, &omega;&ast;, is reconstructible. Further, the property of being a normal space is consistently non-reconstructible. Under the Continuum Hypothesis, the compact Hausdorff space &omega;&ast; has a non-normal reconstruction, namely the space &omega;&ast;&bsol;&lcub;p&rcub; for a P-point p of &omega;&ast;. More generally, the existence of an uncountable cardinal &kappa; satisfying &kappa; = &kappa;<sup>&lt;&kappa;</sup> implies that there is a normal space with a non-normal reconstruction. The final chapter discusses the Stone-&Ccaron;ech compactification and the Stone-&Ccaron;ech remainder of spaces &omega;&ast;&bsol;&lcub;x&rcub;. Assuming the Continuum Hypothesis, we show that for every point x of &omega;&ast;, the Stone-&Ccaron;ech remainder of &omega;&ast;&lcub;x&rcub; is an &omega;<sub>2</sub>-Parovi&ccaron;enko space of cardinality 2<sup>2<sup>c</sup></sup> which admits a family of 2<sup>c</sup> disjoint open sets. This implies that under 2<sup>c</sup> = &omega;<sub>2</sub>, the Stone-&Ccaron;ech remainders of &omega;&ast;&bsol;&lcub;x&rcub; are all homeomorphic, regardless of which point x gets removed.
78

L'Afrique du Sud post-apartheid : le temps de la reconstruction, des réformes et des mutations à travers le Globe and Mail de Toronto et le Times de Londres (1994-2004)

Beauregard, Marie-Claude January 2016 (has links)
La décennie 1994-2004 est d’une importance majeure pour l’Afrique du Sud nouvellement démocratique. Au cours de cette période, le pays jette les bases de sa reconstruction à travers la mise en place de réformes politiques, économiques et sociales afin de combattre les méfaits de quarante années d’apartheid et de poser les jalons de son développement. Dans ce contexte, les médias internationaux ont porté une attention particulière à ces nombreux changements, plus spécifiquement la presse écrite canadienne et britannique, en particulier le Globe and Mail et le Times. Notre mémoire s’intéresse donc au traitement fait par ces deux quotidiens, l’un torontois l’autre londonien, de la reconstruction sud-africaine et ce, à travers l’analyse de thèmes précis et de ses réformes marquantes. Il sera plus spécifiquement question des réformes politiques et constitutionnelles avec la figure de Nelson Mandela, héros de la lutte contre l’apartheid, père de la « nation arc-en-ciel » ainsi que celle de son successeur à la présidence sud-africaine en 1999, Thabo Mbéki. Aussi, la Commission Vérité et Réconciliation et la nouvelle Constitution, toutes deux mises en place durant l’année 1996 sont majeures puisqu’elles dictent la nouvelle identité donnée au pays. Les réformes socioéconomiques de la reconstruction ont également attirés l’attention de nos deux journaux. Particulièrement, nous analyserons les points de vue de ceux-ci concernant le Reconstruction and Development Programme (RDP) ainsi que de la « discrimination positive » et du Black Economic Empowerment (BEE), deux mesures censées contribuer à l’amélioration de la qualité de vie de la population et à effacer les profondes inégalités socioéconomiques léguées par l’apartheid. Or, cet espoir d’une vie meilleure laisse rapidement place à un désenchantement. La forte criminalité et la dramatique explosion du VIH-sida dans une nouvelle Afrique du Sud qui cherche à se reconstruire a beaucoup retenu l’attention du Globe and Mail et du Times. Ces deux défis de taille s’avèrent être l’envers de la médaille du miracle sud-africain et ne manquent pas d’attirer l’attention des deux journaux, mettant clairement en évidence les « ratés » socioéconomiques » de la reconstruction.
79

3D RECONSTRUCTION OF RyR1 AND STRUCTURAL VALIDATION UNDER DIFFERENT LEVELS OF NOISE

Lobo, Joshua J 01 January 2014 (has links)
Ryanodine receptors (RyR) are intracellular channels that are intricately involved in Ca2+ release. These channels large membrane proteins~2.26MDa in size. In this multi-goal project firstly we successfully studied the gating mechanics of the RyR1 in the presence of Mg2+. We used single particle reconstruction and image processing techniques to obtain the 3D structure of the RyR1 with Mg2+. The 3D structure in the presence of Mg2+ and an ATP analog is the closest representation of human physiological conditions. The open and closed state structures of RyR1 are known. However, the physiologically closed state has not been studied before. Understanding this structure will help in the understanding of protein interactions. Our second goal was the validation of this 3D structure under different levels of noise. Validation under different noise levels analyzed the problem of noise bias is present in the field of cryo-EM and single particle reconstruction in select cases.
80

Diagnostic, reconstruction et identification des défauts capteurs et actionneurs : application aux station d’épurations des eaux usées / Diagnosis and sensors and actuators fault reconstruction : application to WWTPs

Methnani, Salowa 17 December 2012 (has links)
Ce travail de thèse propose une méthode générale de reconstruction de défauts. Cette méthode donne un aperçu sur le problème d’observabilité des entrées inconnues. Par la suite, une méthodologie de détection et d’isolation de défauts capteurs et actionneurs est proposée. Le schéma de FDI est basé sur une banque d’observateurs. L’implémentation de cette méthode pour un modèle ASM1 réduit conduit à une table de signature fortement localisante.La deuxième partie porte sur la problématique de « l’observation des systèmes non linéaires ». Le filtre de Kalman étendu (FKE) est l’un des observateurs les plus largement utilisé à cette fin. Cependant, la convergence de cet observateur n’est pas prouvée. Lorsque le FKE est appliqué à un système mis sous une forme canonique d’observabilité, il acquiert, des propriétés de convergence exponentielle globales. Cependant, ce dernier entraine une amplification de bruit. Afin de combiner l’efficacité d’un FKE en termes de lissage de bruit, et la réactivité d’un OKE grand gain face aux larges variations, [Boizot et al., 2010] ont proposé un observateur adaptatif. Ainsi, cet observateur est appliqué au système non-linéaire MIMO d’une station d’épuration biologique. Une étude comparative entre ces trois observateurs est menée afin de mettre en évidence la pertinence de l’observateur adaptatif. / This thesis proposes a general methodology for identifying and reconstructing sensor faults on dynamical processes. This identification theory provides a general framework for the problem of "observability with unknown inputs". Next, a framework for fault detection and isolation of sensors and actuators is proposed. The FDI sheme is based on bank of high-gain observers. A simulation study of a waste water treatment plant shows the effectiveness of the proposed approach.The second point evoked in the thesis is the observability of nonlinear dynamic systems and state estimation. The Extended Kalman Filter (EKF) is a widely used observer for such nonlinear systems. However, it suffers from the lack of theoretical justifications. The EKF, when applied to a system put in a normal form of observability, it acquires the property of global exponential convergence. Unfortunately, this latter observer (HG-EKF) is very sensitive to measurement noise. In order to combine the behaviors of the EKF (efficiency with respect to noise smoothing) and of the HG-EKF (reactivity to large estimation errors), (Boizot et al, 2010) proposed an adaptive high gain observer. This observer is applied to a MIMO nonlinear system of an Activated Sludge Process. A comparison study of the performances of the three observers under consideration is carried out. Results show a clearly better state estimation for the adaptive observer.

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