Dissertations / Theses on the topic 'Surface normale'
To see the other types of publications on this topic, follow the link: Surface normale.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Surface normale.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Snoussi, Jawad. "Limites d'espaces tangents à une surface normale." Aix-Marseille 1, 1998. http://www.theses.fr/1998AIX11037.
Full textAbstract:
Dans ce travail, nous donnons des caracterisations numeriques et geometriques de l'ensemble des limites d'hyperplans tangents a un germe de surface normale (s,0) plongee dans c n. Nous demontrons qu'un hyperplan h n'est pas une limite d'hyperplans tangents a s en 0 si et seulement si la section de h avec s est reduite et son nombre de milnor est minimum parmi ceux des sections hyperplanes reduites. Il est connu que l'ensemble des limites d'hyperplans tangents a la surface s en 0 est la reunion de l'ensemble des hyperplans tangents au cone tangent de s en 0 et de l'ensemble des hyperplans contenant des generatrices particulieres du cone dites tangentes exceptionnelles de s en 0. On sait egalement que ces tangentes exceptionnelles correspondent aux points fixes du systeme lineaire des courbes polaires par l'eclatement de l'origine dans s. Nous prouvons ici que les tangentes exceptionnelles de s en 0 correspondent aux points ou la famille des sections hyperplanes de s n'admet pas de resolution simultanee faible, ce qui nous permet de les determiner precisement sur le diviseur exceptionnel de l'eclatement de l'origine. En etendant la notion de composantes de tyurina a une desingularisation raisonnable d'une surface normale, nous demontrons que ces composantes se contractent sur des points fixes du systeme lineaire des courbes polaires par l'eclatement de l'origine. En appliquant ces techniques a l'etude des pinceaux de courbes sur un germe de surface normale, nous determinons les valeurs dites speciales d'un pinceau de courbe, c'est a dire celles pour lesquelles la topologie de la courbe n'est pas generique.
2
Roman, Adriana. "Méthodes d'indentation normale et transverse appliquées à l'étude des propriétés mécaniques des films et révêtements." Lille 1, 2000. https://pepite-depot.univ-lille.fr/RESTREINT/Th_Num/2000/50376-2000-276.pdf.
Full textAbstract:
Le travail presente dans ce memoire entre dans le cadre du developpement des activites du laboratoire dediees a la determination par indentation de la durete des materiaux. La premiere partie du document est consacree a l'etude de revetements de nickel-phosphore obtenus industriellement et etudies ici dans deux etats de traitements thermiques de recuit a 300\c et 600\c. Pour ces deux modalites il a ete possible de determiner la tenacite des revetements a partir de l'observation des fissures de type palmqvist, generees par indentation vickers normale. Dans la seconde partie l'effort est porte sur la determination de la durete de films de diamant en comparant les resultats obtenus a partir de quelques modeles parmi les plus utilises. Ces modeles decrivent la durete composite superficielle en fonction de la durete du film et du substrat. Enfin, en cherchant a s'affranchir de la connaissance du module d'elasticite du film necessaire dans le modele de chicot et lesage, on propose un nouveau modele de description de la durete composite permettant de prendre en compte la transition de comportement de type substrat ou de type film en fonction de la profondeur relative d'indentation.
3
Maritaud, Karl. "Rendu réaliste d'arbres vus de près en images de synthèse." Limoges, 2003. http://aurore.unilim.fr/theses/nxfile/default/26d2f3b6-ee12-4232-956d-706abdfbda53/blobholder:0/2003LIMO0049.pdf.
Full textAbstract:
La plupart des travaux pour représenter des arbres en Infographie se sont orientés sur des méthodes conçues pour des points de vue éloignés où les détails de l'écorce et des feuilles ne sont pas perceptibles. Le rendu réaliste d'arbres vus de près reste un problème ouvert et difficile, essentiellement à cause de la complexité visuelle de l'écorce. Ici, des méthodes basées-image sont proposées pour extraire le relief et la couleur d'une texture réelle d'écorce à partir d'une simple photographie, sans manipulation compliquée, et ensuite pour synthétiser des textures 3D d'écorces réalistes. Une méthode est proposée pour appliquer ces textures, sans répétition ni discontinuité, sur des branches modélisées par déplacement de surfaces implicites mélangées sans gonflement. D'autre part, une technique est proposée pour extraire le relief des nervures des feuilles. Ensemble, ces méthodes nous permettent d'obtenir un haut niveau de réalisme visuel pour représenter des arbres vus de prèsMost of the research in the rendering of trees in Computer Graphics has focused on methods designed for viewpoints at a certain distance where the details of the bark and leaves are not perceptible. Rendering realistic trees at a short distance remains an open and difficult problem, essentially due to the visual complexity of bark textures. Here, image-based methods are proposed to extract the relief and color from a single photograph of real bark texture, without any complicated manipulations, and then to automatically synthesize realistic 3D bark textures. A method is proposed to apply these textures, with neither repetition nor discontinuities on the texture, onto branches modeled by displacement-mapped implicit surfaces, which are blended without bulge. Moreover, a technique for extracting the relief of leaf veins is proposed. Together, these methods allow us to achieve a high degree of visual realism for rendering close-up views of trees
4
Margirier, Audrey. "Tectonique et processus d’exhumation des Cordillères Blanche et Noire en contexte de subduction horizontale (Nord Pérou)." Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAU023/document.
Full textAbstract:
Ma thèse se focalise sur l'étude des mécanismes qui ont conduit au soulèvement et à la construction du relief dans les Andes du Nord du Pérou. Dans cette région, la Cordillère Blanche forme les plus hauts sommets péruviens (> 6000 m) et constitue une anomalie à l'échelle des Andes. La morphologie de cette région des Andes est marquée par un pluton de forme atypique, allongé et à l'affleurement sur plus de 150 km. Ce pluton est bordé par une faille normale de plus de 200 km de long. La présence de cette faille normale majeure en contexte de subduction plane reste surprenante car ces zones de subduction planes semblent induire une augmentation du raccourcissement dans la plaque chevauchante. Mon travail a eu pour objectifs de caractériser les variations de l'état de contraintes régional, l'âge du soulèvement et de discuter les processus géodynamiques qui ont contribué à la formation du relief. Dans ce cadre, j'ai utilisé une approche pluridisciplinaire impliquant sur plusieurs échelles spatio-temporelles et comprenant à la fois de nouvelles données de terrain, leur analyse et leur modélisation.Mes données de microtectonique indiquent qu'il est possible de générer de l'extension au dessus d'une subduction plane à l'échelle régionale. Ces données sont en contradiction avec l'augmentation du raccourcissement classiquement attendue dans la plaque chevauchante. Mes nouvelles données de thermochronologie basse température et leur modélisation montrent une augmentation de l'exhumation induite par le soulèvement de la Cordillère Occidentale à 15 Ma. En les confrontant aux modèles précédents, je propose un soulèvement régional lié à l'aplatissement de la subduction et à la topographie dynamique associée.J'ai également étudié l'impact de l'arc Miocène sur le soulèvement à une échelle plus locale. Pour cela, j'ai compilé tous les âges de refroidissement du pluton disponibles dans la littérature. En parallèle, j'ai obtenu les premières données de profondeur de mise en place du batholite de la Cordillère Blanche. Cela m'a permis de proposer une structure du batholite en sills empilés puis basculés vers l'est. De plus, la modélisation des variations spatio-temporelle des taux d'érosion à partir des données de thermochronologie basse température indique une augmentation importante des taux d'érosion dans la Cordillère Blanche à partir de 2 Ma. L'arc Miocène ne semble donc pas contribuer significativement au soulèvement malgré sa probable contribution à l'épaississement de la lithosphère. En revanche, l'érosion glaciaire récente semble contribuer fortement à l'exhumation de la Cordillère Blanche et au basculement du batholite.Dans la dernière partie de ma thèse, pour quantifier l'importance de l'érosion dans la création du relief et le soulèvement, j'ai modélisé l'évolution du paysage de la région (FastScape). Mes modélisations numériques démontrent le rôle majeur de l'érosion et du rebond flexural associé dans la création du relief et les taux de soulèvement. Pour finir, basée sur les données de la littérature et celles apportées par mon travail de thèse, je propose un nouveau modèle pour expliquer la faille normale de la Cordillère Blanche dans son contexte régional. Ce modèle implique une faille normale d'extrado et l'érosion importante du mur de la failleMy thesis focuses on the mechanisms that controlled the uplift and construction of the relief in the northern Peruvian Andes. In this area, the Cordillera Blanca forms the highest peaks in Peru (> 6000 m), which is a topographic anomaly across the Andes. The morphology of the Cordillera Blanca is marked by an elongated pluton, which outcrops over 150 km. In addition, this pluton is bordered by the largest normal fault from South America. The presence of this major normal fault in a flat-slab context remains surprising because flat slabs usually induce an increase of the shortening in the overriding plate. The aim of my work is to characterize the variations of the regional stress field, the age of the uplift and discuss the geodynamic processes that contributed to relief building. To address these issues, I used a multidisciplinary approach involving new field data, their analysis and modeling.My microtectonic dataset reveals regional extension above the Peruvian flat-slab. This data contradicts the expected increase of shortening in the overriding plate. Modeling my new thermochronologic data shows an increase in the exhumation rates induced by the uplift of the Cordillera Occidental since 15 Ma. I propose that the regional uplift relates to the flattening of the subduction and associated dynamic topography.To address the impact of the Miocene arc on the uplift at a more local scale, I compiled the cooling ages of the pluton available in the literature. In parallel, I obtained the first amphibole thermo-barometry data that constrains emplacement depth of the Cordillera Blanca batholith. Following these data, I propose that the batholith is structured in eastward-tilted sills. In addition, modeling of the space and time variations of erosion rates based on the inversion of thermochronologic data indicates that erosion rates significantly increased in the Cordillera Blanca since 2 Ma. The Miocene arc seems to insignificantly contribute to the local uplift despite its contribution to the thickening of the lithosphere. Thus, I suggest that the recent glacial erosion contributes to the exhumation of the Cordillera Blanca and subsequent tilting of the batholith.Then, I modeled the landscape evolution for the Cordillera Blanca region to quantify the contribution of erosion in the relief building and the uplift. My numerical models (FastScape) evidence the importance of erosion and associated flexural rebound in fostering relief building and the uplift rates.Finally, based on all available data, I propose a new regional model to explain the Cordillera Blanca normal fault. This model implies an extrado normal fault and erosion of the footwall
5
Valibouse, Pierre. "Mesure des caractéristiques intrinsèques des matériaux dans l'eau, avec un tube à impédance en incidence normale." Compiègne, 1990. http://www.theses.fr/1990COMPD317.
Full textAbstract:
La discrétion acoustique prenant une part de plus en plus importante dans la lutte sous-marine, des matériaux de masquage acoustique sont utilises pour atténuer le rayonnement acoustique des sous-marins. Il s'avère donc nécessaire de connaître parfaitement les caractéristiques de ces matériaux afin d'en prévoir leur efficacité. Actuellement, les moyens acoustiques de caractérisation de ces matériaux ne permettent d'obtenir qu'une information relative globale sur le matériau, et non pas de connaître ses caractéristiques intrinsèques telle la célérité complexe des ondes. Le travail décrit dans cette thèse concerne le développement d'un système acoustique s'inspirant du principe des tubes à impédance aériens, qui permet d'accéder à la célérité complexe des ondes dans le matériau. Malgré le couplage fluide-structure induit par la présence de l'eau dans le tube, la plage d'utilisation de ce moyen d'essais se situe entre 50 et 2000 Hz. L'étude par éléments finis du comportement de l'échantillon placé dans le tube et soumis à une pression acoustique a permis de déterminer les conditions limites mécaniques devant lui être appliquées de manière à modéliser simplement son comportement (identique à celui d'une plaque de surface infinie). Les essais acoustiques ont mis en évidence les limites des méthodes classiques de mesure utilisées dans les tubes aériens pour accéder à la célérité complexe des matériaux. En modélisant le tube à impédance par un système multi-couches infini, l'identification par optimisation sur les célérités complexes du matériau et de l'eau à l'aide de la méthode du simplex, des fonctions de transfert théorique et expérimentale entre deux capteurs, permet d'obtenir le spectre de la célérité complexe du matériau des les basses fréquences. Les fonctions de transfert sont mesurées à l'aide des techniques référentielles ou sélectives « H1 ». Ce moyen d'essais permet aussi l'étude du comportement des matériaux soumis à une pression hydrostatique.
6
Enaim, Mohammed. "Etude de la co-forgeabilité d'u multi-matériau : application à un coupe d'acier." Thesis, Paris, ENSAM, 2019. http://www.theses.fr/2019ENAM0002/document.
Full textAbstract:
Le forgeage multi-matériaux est un procédé permettant la mise en forme et l’assemblage simultanés de matériaux différents. Ce procédé permet d’obtenir des pièces multi-matériaux avec le « bon matériau placé au bon endroit ». L’objectif des travaux de thèse est de définir les conditions nécessaires à l’établissement de la liaison métallurgique par forgeage à l’interface d’un couple d’aciers. Dans un premier temps, l’état de l’art a servi à l’identification les phénomènes physiques accompagnant le forgeage multi-matériaux et les paramètres clés pilotant l’établissement de la liaison métallurgique. Le principe de base de l’établissement d’une liaison passe par la fragmentation des oxydes en surface des matériaux et par l’application d’une pression de contact favorisant le contact entre les matériaux nus et la diffusion. Les deux paramètres clés identifiés sont donc la pression normale de contact et l’expansion de surface. Le protocole de caractérisation du co-forgeage mis en place comporte trois essais « simples » permettant de solliciter les interfaces avec des pressions et des expansions différentes. Ces dernières, estimées par simulation numérique de l’essai, sont mises en relation avec la qualité des liaisons obtenues évaluée, quant à elle, au travers d’observations métallographiques. Les premières simulations permettent de dimensionner les campagnes expérimentales. Celles-ci sont ensuite conduites sur les moyens de mise en forme de la plateforme VULCAIN. Les efforts de mise en forme et la géométrie globale des pièces et la répartition de matière servent de base à l’identification des paramètres de la simulation. La simulation ainsi obtenue et les observations métallographiques aux interfaces sont ensuite mises en lien. Cette démarche a permis de confirmer l’importance du rôle joué par la pression de contact et l’expansion de surface sur l’établissement d’une liaison au cours de la mise en forme du multi-matériaux. La répartition et la forme des particules d’oxydes semblent liées au chemin thermomécanique subi par l’interfaceThe multi-material forging is a forming process allowing, simultaneously, the welding and shaping of multi-material parts with the right material at the right place. The purpose of the presented work is to identify the necessary conditions to obtain a metallurgical bond during forming between two different grades of steel. First, the state of the art allowed the identification of the physical phenomena occurring during multi-material forging and the determination of the key parameters of the bonding which are the contact pressure and the surface expansion at the both sides of the interface. The mechanisms to establish metallurgical bond by forging are based on the breaking and the dispersion of the oxide layer at the interface then the extrusion of the soft material through the voids generated between the oxide fragments. Second, the characterization methodology of this work is presented. It consists of three “simple” forming tests leading to different interface conditions (contact pressure and surface expansion). The first simulations allow the design of the experimental plan for each test. The comparison between simulations and experiments allows the identification of physical parameters of the simulation. Then, the contact pressure and the surface expansion of the identified simulations are used to analyze the metallographic structure and the bonding at the interface.The developed work confirms the major effect of the contact pressure and the surface expansion on the establishment of a metallurgical bond during multi-material forming. The size and the shape of the oxide particles seem to depend on the thermomechanical path at the interface
7
Li, Huibin. "Towards three-dimensional face recognition in the real." Phd thesis, Ecole Centrale de Lyon, 2013. http://tel.archives-ouvertes.fr/tel-00998798.
Full textAbstract:
Due to the natural, non-intrusive, easily collectible, widespread applicability, machine-based face recognition has received significant attention from the biometrics community over the past three decades. Compared with traditional appearance-based (2D) face recognition, shape-based (3D) face recognition is more stable to illumination variations, small head pose changes, and varying facial cosmetics. However, 3D face scans captured in unconstrained conditions may lead to various difficulties, such as non-rigid deformations caused by varying expressions, data missing due to self occlusions and external occlusions, as well as low-quality data as a result of some imperfections in the scanning technology. In order to deal with those difficulties and to be useful in real-world applications, in this thesis, we propose two 3D face recognition approaches: one is focusing on handling various expression changes, while the other one can recognize people in the presence of large facial expressions, occlusions and large pose various. In addition, we provide a provable and practical surface meshing algorithm for data-quality improvement. To deal with expression issue, we assume that different local facial region (e.g. nose, eyes) has different intra-expression/inter-expression shape variability, and thus has different importance. Based on this assumption, we design a learning strategy to find out the quantification importance of local facial regions in terms of their discriminating power. For facial description, we propose a novel shape descriptor by encoding the micro-structure of multi-channel facial normal information in multiple scales, namely, Multi-Scale and Multi-Component Local Normal Patterns (MSMC-LNP). It can comprehensively describe the local shape changes of 3D facial surfaces by a set of LNP histograms including both global and local cues. For face matching, Weighted Sparse Representation-based Classifier (W-SRC) is formulated based on the learned quantification importance and the LNP histograms. The proposed approach is evaluated on four databases: the FRGC v2.0, Bosphorus, BU-3DFE and 3D-TEC, including face scans in the presence of diverse expressions and action units, or several prototypical expressions with different intensities, or facial expression variations combine with strong facial similarities (i.e. identical twins). Extensive experimental results show that the proposed 3D face recognition approach with the use of discriminative facial descriptors can be able to deal with expression variations and perform quite accurately over all databases, and thereby has a good generalization ability. To deal with expression and data missing issues in an uniform framework, we propose a mesh-based registration free 3D face recognition approach based on a novel local facial shape descriptor and a multi-task sparse representation-based face matching process. [...]
8
Mesmay, Arnaud de. "Topics in low-dimensional computational topology." Paris, École normale supérieure, 2014. https://theses.hal.science/tel-04462650v1.
Full textAbstract:
La topologie, c’est-à-dire l’étude qualitative des formes et des espaces, constitue un domaine classique des mathématiques depuis plus d’un siècle, mais il n’est apparu que récemment que pour de nombreuses applications, il est important de pouvoir calculer informatiquement les propriétés topologiques d’un objet. Ce point de vue est la base de la topologie algorithmique, un domaine très actif à l’interface des mathématiques et de l’informatique auquel ce travail se rattache. Les trois contributions de cette thèse concernent le développement et l’étude d’algorithmes topologiques pour calculer des décompositions et des déformations d’objets de basse dimension, comme des graphes, des surfaces ou des 3-variétés. Le premier problème auquel nous nous attaquons traite de déformations : comment peut-on tester si deux graphes dessinés sur une même surface sont isotopes, c’est-à-dire si l’on peut déformer continûment l’un en l’autre ? Ce type de question est relié à des problèmes pratiques que l’on rencontre par exemple dans les systèmes d’information géographique ou les métamorphoses (morphings). En nous appuyant sur des concepts de géométrie hyperbolique et de la théorie des mapping class groups, nous établissons d’abord un critère combinatoire pour caractériser l’isotopie, ce qui reprouve et améliore un résultat de Ladegaillerie de 1984. Ensuite, en combinant ceci avec des algorithmes antérieurs pour tester l’homotopie de courbes, nous fournissons des algorithmes efficaces pour résoudre ce problème d’isotopie de graphes. Nous déplaçons ensuite notre étude vers des problèmes de décompositions, en nous intéressant à la découpe de surfaces le long de courbes ou de graphes respectant certaines propriétés topologiques, ce qui est une routine importante en algorithmique des graphes ou en infographie, parmi d’autres domaines. En établissant une forte connexion avec le cas continu, ainsi qu’en étudiant un modèle discret de surfaces aléatoires, nous améliorons les meilleures bornes connues pour plusieurs schémas de découpe. Cela prouve en particulier une conjecture de Przytycka et Przytycki datant de 1993, et fournit également un nouvel algorithme pour calculer des décompositions en pantalons courtes. Enfin, nous montons d’une dimension, où les meilleurs algorithmes connus pour de nombreux problèmes topologiques (comme le célèbre problème du noeud) sont exponentiels. La plupart de ces algorithmes reposent sur les surfaces normales, un objet omniprésent pour étudier les surfaces plongées dans une 3-variété. Nous étudions une relaxation naturelle de cette notion, les surfaces normales immergées, dont la meilleure structure algébrique en fait de bons candidats pour obtenir des algorithmes polynomiaux pour des problèmes topologiques. Dans ce travail, nous montrons qu’utiliser des surfaces normales immergées mène naturellement à un problème de détection de singularités, et nous prouvons que celui-ci est NP-dur ; c’est un résultat notable car l’on dispose de très peu de preuves de difficulté en topologie en 3 dimensions. Notre réduction s’appuie sur une connexion avec une classe restreinte de problèmes de satisfaction de contraintes qui a été partiellement classifiée par FederTopology is the area of mathematics investigating the qualitative properties of shapes and spaces. Although it has been a classical field of study for more than a century, it only appeared recently that being able to compute the topological features of various spaces might be of great value for many applications. This idea forms the core of the blossoming field of computational topology, to which this work belongs. The three contributions of this thesis deal with the development and the study of topological algorithms to compute deformations and decompositions of low-dimensional objects, such as graphs, surfaces or 3-manifolds. The first question we tackle concerns deformations: how can one test whether two graphs embedded on the same surface are isotopic, i. E. , whether one can be deformed continuously into the other? This kind of problems is relevant to practical problems arising with morphings or geographic information systems, for example. Relying on hyperbolic geometry and ideas from the theory of mapping class groups, we first establish a combinatorial criterion to characterize isotopy, reproving and strengthening a result of Ladegaillerie (1984). Combined with earlier algorithms on the homotopy of curves, this allows us in turn to provide efficient algorithms to solve this graph isotopy problem. We then shift our focus to decompositions, by investigating how to cut surfaces along curves or graphs with prescribed topological properties, which is an important routine in graph algorithms or computer graphics, amongst others domains. By establishing a strong connection with the continuous setting, as well as studying a discrete model for random surfaces, we improve the best known bounds for several instances of this problem. In particular, this proves a conjecture of Przytycka and Przytycki from 1993, and one of our new bounds readily translates into an algorithm to compute short pants decompositions. Finally, we move up one dimension, where the best known algorithms for many topological problems, like for example unknot recognition, are exponential. Most of these algorithms rely on normal surfaces, a ubiquitous tool to study the surfaces embedded in a 3-manifold. We investigate a relaxation of this notion called immersed normal surfaces, whose more convenient algebraic structure makes them good candidates to solve topological problems in polynomial time. We show that when working with immersed normal surfaces, a natural problem on the detection of singularities arises, and we prove it to be NP-hard – this is noteworthy as hardness results are very scarce in 3-dimensional topology. Our reduction works by establishing a connection with a restricted class of constraint satisfaction problems which has been partially classified by Feder
9
Valdivia, Paola Tatiana Llerena. "Correção de normais para suavização de nuvens de pontos." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/55/55134/tde-19032014-145046/.
Full textAbstract:
Nos anos recentes, suavização de superfícies é um assunto de intensa pesquisa em processamento geométrico. Muitas das abordagens para suavização de malhas usam um esquema de duas etapas: filtragem de normais seguido de um passo de atualização de vértices para corresponder com as normais filtradas. Neste trabalho, propomos uma adaptação de tais esquemas de duas etapas para superfícies representadas por nuvens de pontos. Para isso, exploramos esquemas de pesos para filtrar as normais. Além disso, investigamos três métodos para estimar normais, analisando o impacto de cada método para estimar normais em todo o processo de suavização da superfície. Para uma análise quantitativa, além da comparação visual convencional, avaliamos a eficácia de diferentes opções de implementação usando duas medidas, comparando nossos resultados com métodos de suavização de nuvens de pontos encontrados a literaturaIn the last years, surface denoising is a subject of intensive research in geometry processing. Most of the recent approaches for mesh denoising use a twostep scheme: normal filtering followed by a point updating step to match the corrected normals. In this work, we propose an adaptation of such two-step approaches for point-based surfaces, exploring three different weight schemes for filtering normals. Moreover, we also investigate three techniques for normal estimation, analyzing the impact of each normal estimation method in the whole point-set smoothing process. Towards a quantitative analysis, in addition to conventional visual comparison, we evaluate the effectiveness of different choices of implementation using two measures, comparing our results against state-of-art point-based denoising techniques. Keywords: surface smoothing; point-based surface; normal estimation; normal filtering.
10
Lootens, Didier. "Ciments et suspensions concentrées modèles : écoulement, encombrement et floculation." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2004. http://tel.archives-ouvertes.fr/tel-00007217.
Full textAbstract:
Nous reportons ici le comportement rhéologique de suspensions concentrées - ou pâte - de particules granulaires ou colloïdales de ciment ou de silice sphérique et monodisperse. Le système modèle de particules de silice est utilisé pour pouvoir contrôler les propriétés physicochimiques de la suspension. Notre projet de recherche se centre sur deux points qui s'intéressent aux propriétés du coulis frais : (i) le premier est l'étude du processus de structuration par coagulation au repos et sa relation avec la prise. Nous avons utilisé des outils (ultrason, confocal) adaptés pour suivre et interpréter la coagulation et la prise du ciment.(ii). Le second est l'étude d'un phénomène de structuration dynamique, sous écoulement, typique des suspensions très concentrées et appelé " jamming ". Nous montrons que l'apparition de ce régime d'encombrement va de pair avec des fluctuations géantes de contraintes, avec une statistique caractéristique des événements critiques auto-organisés. L'état de surface des grains et du frottement intergranulaire est un paramètre important dans le blocage sous cisaillement. La simultanéité des fluctuations des efforts normaux et des efforts tangentiels aussi que des visualisations microscopiques suggère fortement que la formation de chaînes de contacts frottants est à l'origine du phénomène.
11
Szilárd, Ágnes. "Resolution graphs of normal surface singularities /." The Ohio State University, 1999. http://rave.ohiolink.edu/etdc/view?acc_num=osu148819010987053.
Full text
12
Moore, Kathleen Dorothy. "The Impact of Surface Normals on Appearance." W&M ScholarWorks, 2016. https://scholarworks.wm.edu/etd/1477068344.
Full textAbstract:
The appearance of an object is the result of complex light interaction with the object. Beyond the basic interplay between incident light and the object's material, a multitude of physical events occur between this illumination and the microgeometry at the point of incidence, and also beneath the surface. A given object, made as smooth and opaque as possible, will have a completely different appearance if either one of these attributes - amount of surface mesostructure (small-scale surface orientation) or translucency - is altered. Indeed, while they are not always readily perceptible, the small-scale features of an object are as important to its appearance as its material properties. Moreover, surface mesostructure and translucency are inextricably linked in an overall effect on appearance. In this dissertation, we present several studies examining the importance of surface mesostructure (small-scale surface orientation) and translucency on an object's appearance. First, we present an empirical study that establishes how poorly a mesostructure estimation technique can perform when translucent objects are used as input. We investigate the two major factors in determining an object's translucency: mean free path and scattering albedo. We exhaustively vary the settings of these parameters within realistic bounds, examining the subsequent blurring effect on the output of a common shape estimation technique, photometric stereo. Based on our findings, we identify a dramatic effect that the input of a translucent material has on the quality of the resultant estimated mesostructure. In the next project, we discuss an optimization technique for both refining estimated surface orientation of translucent objects and determining the reflectance characteristics of the underlying material. For a globally planar object, we use simulation and real measurements to show that the blurring effect on normals that was observed in the previous study can be recovered. The key to this is the observation that the normalization factor for recovered normals is proportional to the error on the accuracy of the blur kernel created from estimated translucency parameters. Finally, we frame the study of the impact of surface normals in a practical, image-based context. We discuss our low-overhead, editing tool for natural images that enables the user to edit surface mesostructure while the system automatically updates the appearance in the natural image. Because a single photograph captures an instant of the incredibly complex interaction of light and an object, there is a wealth of information to extract from a photograph. Given a photograph of an object in natural lighting, we allow mesostructure edits and infer any missing reflectance information in a realistically plausible way.
13
Spring, F. A. "Surface glycoproteins of normal and leukaemic leucocytes." Thesis, University of Bristol, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370674.
Full text
14
Friedel, Ilja Heinrich Schröder Peter. "Approximation of surfaces by normal meshes /." Diss., Pasadena, Calif. : California Institute of Technology, 2005. http://resolver.caltech.edu/CaltechETD:etd-05242005-164959.
Full text
15
Cico, Alba. "Molecular mechanisms of normal erythropoiesis." Thesis, Sorbonne Paris Cité, 2017. http://www.theses.fr/2017USPCC311.
Full textAbstract:
Un être humain adulte produit environ deux millions d’érythrocytes par seconde, à travers un processus connu sous le nom d’érythropoïèse. L’érythropoïèse est contrôlée par une balance entre prolifération et différenciation finement régulée. L’expression des gènes impliqués dans ces deux processus distincts, est régulée extrinsèquement (cytokines) et intrinsèquement (microenvirennement métabolique, facteurs de transcription). Les facteurs de transcription, fonctionnent sous forme de complexes multiprotéiques et contrôlent l’activité transcriptionnelle des cellules. Parmi eux, le complexe LDB1 joue un rôle clé dans la régulation de la balance prolifération/différenciation pendant l’érythropoïèse, puisqu’il contrôle l’expression des gènes impliquées dans ces deux processus. Au cours de mon doctorat, nous avons d’abord caractérisé les mécanismes moléculaires de la “pré-activation” des gènes de différenciation, également nommés marqueurs erythroides, dans les progéniteurs erythroides immatures. La pré-activation, est un état dans lequel, les gènes sont exprimés à un niveau basal très bas, permissif pour une activation significative pendant la différenciation. Nous avons ainsi montré que les répresseurs : ETO2, IRF2BP2 et NCOR1, interagissent avec le complexe LDB1, et lient ensemble les gènes des marqueurs erythroides et les répriment. Au cours de l’érythropoïèse, ces corépresseurs sont déstabilisés et LDB1 agit alors comme un activateur. En ce qui concerne les gènes de prolifération, nous avons observé que le complexe LDB1 est déstabilisé au niveau de ces loci pendant l’érythropoïèse. Afin d’étudier les mécanismes moléculaires de la répression génique des gènes de prolifération au cours de l’érythropoïèse, nous avons choisi d’étudier Myb, une cible du complexe LDB1, étudié auparavant dans le laboratoire. Nous avons testé trois facteurs : ZEB1, OGT et RNF12, en tant que candidats dans la répression de Myb. Nous avons montré que RNF12 est le seul facteur intervenant dans la transcription de Myb. RNF12 régule Myb probablement par une modification de complexes épigénétiquesEvery second about 2 million erythrocytes are produced in the adult human body, through a process called erythropoiesis. Erythropoiesis is controlled by a highly regulated balance between proliferation and differentiation. Expression of genes responsible for cell proliferation and differentiation is controlled external (such as cytokines) and internal (such as metabolic microenvironment and transcription factors). Transcription factors bind DNA and recruit co-factors generating transcriptional complexes. The LDB1 complex has a key role in the balance between erythroid proliferation vs. differentiation, since it regulates genes involved in both processes. During my Ph.D., we investigated the molecular mechanisms that LDB1 employs to regulate genes with divergent function. We first showed that in erythroid progenitors, differentiating genes, also known as erythroid markers, are primed. Gene priming consists of genes expressed in low basal but significant levels in progenitors, which can rapidly be activated during differentiation. We showed that in progenitors, ETO2, IRF2BP2 and NCOR1, bind the LDB1 complex therefore generating a priming complex. During differentiation, binding of the repressive (ETO2-IRF2BP2-NCOR1) co-factors to the LDB1 complex, is destabilized and genes become active. In genes involved in erythroid proliferation, we observed that LDB1 is destabilized, a feature leading to gene silencing. We used Myb, as a model of gene silencing in the context of regulation by the LDB1 complex. We tested three transcription factors: ZEB1, OGT and RNF12, as candidates in gene silencing. Among these factors, only RNF12 regulates Myb expression, probably through modifications of epigenetic silencers (Polycomb/MLL)
16
König, Sören, and Stefan Gumhold. "Robust Surface Triangulation of Points with Normal Information." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-131385.
Full textAbstract:
The problem of generating a surface triangulation from a set of points with normal information arises in several mesh processing tasks like surface reconstruction or surface resampling. In this paper we present a surface triangulation approach which is based on local 2d delaunay triangulations in tangent space. Our contribution is the extension of this method to surfaces with sharp corners and creases. We demonstrate the robustness of the method on difficult meshing problems that include nearby sheets, self intersecting non manifold surfaces and noisy point samples.
17
König, Sören, and Stefan Gumhold. "Robust Surface Triangulation of Points with Normal Information." Technische Universität Dresden, 2013. https://tud.qucosa.de/id/qucosa%3A27382.
Full textAbstract:
The problem of generating a surface triangulation from a set of points with normal information arises in several mesh processing tasks like surface reconstruction or surface resampling. In this paper we present a surface triangulation approach which is based on local 2d delaunay triangulations in tangent space. Our contribution is the extension of this method to surfaces with sharp corners and creases. We demonstrate the robustness of the method on difficult meshing problems that include nearby sheets, self intersecting non manifold surfaces and noisy point samples.
18
Hillis, Graham S. "Cell surface markers in normal and diseased kidney." Thesis, University of Aberdeen, 1997. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU602001.
Full textAbstract:
Cell surface receptors such as adhesion molecules and connexins are involved in interactions between cells and their surroundings. They play important roles in the normal function of healthy tissues and in the responses of cells to injury. In many cases aberrant repair mechanisms are thought to result in disease and this thesis will assess the expression of cell adhesion molecules (principally the pi integrins) and the connexin43 gap junction protein in normal and diseased kidney The expression of pi integrins on normal human mesangial cells was localised using the alkaline phosphatase anti-alkaline phosphatase immunochemical technique (APAAP) and Western blotting. Expression of mRNA coding for integrins was also assessed using reverse-transcription polymerase chain reaction (RT-PCR). Human mesangial cells in culture expressed the a2, a3, av, pi av and P3 integrin chains. Messenger RNA was detected for these integrin subunits plus the al, a4, a5 and a6 chains. Normal human kidney sections were stained using APAAP and monoclonal antibodies towards a wide range of integrin chains. Within the glomerulus, mesangial cells express al, a2 and pi, epithelial cells a3, av and pi and endothelial cells al, a5 and pi. Tubules express a2, a3, a6, av and pi and the interstitium al and pi. In renal biopsies from patients with IgA disease the main alterations in integrin expression were upregulation of a2, a3, av and pi on damaged tubules, with increased pi expression and de novo a5 and av staining within areas of interstitial damage. These changes were replicated in a wide range of other renal pathologies and correlate with the degree of tubulointerstitial histological damage. Connexin43 (Cx43) is distributed extensively on normal human kidney, particularly on glomerular epithelial cells and intra- and extra-glomerular endothelium. Human mesangial cells in vitro express Cx43 protein and its coding mRNA. There is, however, no expression of Cx43 by the mesangium in vivo. In biopsies from patients with inflammatory renal disease there is strong expression of Cx43 on infiltrating inflammatory cells, in areas of interstitial damage and on damaged tubules. The pattern of Cx43 expression in inflammatory renal disease was very similar to that of intercellular cell adhesion molecule-1 and vascular cell adhesion molecule-1. The work in this thesis has demonstrated the large repertoire of cell surface receptors expressed on normal kidney. The principal alterations in diseased kidney are found within the tubulointerstitum. The potential relevance of these changes in the pathogenesis of renal disease are discussed and possible future avenues of research are suggested.
19
Rieux, Frédéric. "Processus de diffusion discret : opérateur laplacien appliqué à l'étude de surfaces." Thesis, Montpellier 2, 2012. http://www.theses.fr/2012MON20201/document.
Full textAbstract:
Le contexte est la géométrie discrète dans Zn. Il s'agit de décrire les courbes et surfaces discrètes composées de voxels: les définitions usuelles de droites et plans discrets épais se comportent mal quand on passe à des ensembles courbes. Comment garantir un bon comportement topologique, les connexités requises, dans une situation qui généralise les droites et plans discrets?Le calcul de données sur ces courbes, normales, tangentes, courbure, ou des fonctions plus générales, fait appel à des moyennes utilisant des masques. Une question est la pertinence théorique et pratique de ces masques. Une voie explorée, est le calcul de masques fondés sur la marche aléatoire. Une marche aléatoire partant d'un centre donné sur une courbe ou une surface discrète, permet d'affecter à chaque autre voxel un poids, le temps moyen de visite. Ce noyau permet de calculer des moyennes et par là, des dérivées. L'étude du comportement de ce processus de diffusion, a permis de retrouver des outils classiques de géométrie sur des surfaces maillées, et de fournir des estimateurs de tangente et de courbure performants. La diversité du champs d'applications de ce processus de diffusion a été mise en avant, retrouvant ainsi des méthodes classiques mais avec une base théorique identique.} motsclefs{Processus Markovien, Géométrie discrète, Estimateur tangentes, normales, courbure, Noyau de diffusion, Analyse d'imagesThe context of discrete geometry is in Zn. We propose to discribe discrete curves and surfaces composed of voxels: how to compute classical notions of analysis as tangent and normals ? Computation of data on discrete curves use average mask. A large amount of works proposed to study the pertinence of those masks. We propose to compute an average mask based on random walk. A random walk starting from a point of a curve or a surface, allow to give a weight, the time passed on each point. This kernel allow us to compute average and derivative. The studied of this digital process allow us to recover classical notions of geometry on meshes surfaces, and give accuracy estimator of tangent and curvature. We propose a large field of applications of this approach recovering classical tools using in transversal communauty of discrete geometry, with a same theorical base
20
Ceolin, Simone Regina. "Facial shape space using statistical models from surface normals." Thesis, University of York, 2012. http://etheses.whiterose.ac.uk/2087/.
Full textAbstract:
The analysis of shape-variations due to changes in facial expression and gender difference is a key problem in face recognition. In this thesis, we use statistical shape analysis to construct shape-spaces that span facial expressions and gender, and use the resulting shape-model to perform face recognition under varying expression and gender. Our novel contribution is to show how to construct shape-spaces over fields of surface normals rather than Cartesian landmark points. According to this model face needle-maps (or fields of surface normals) are points in a high-dimensional manifold referred to as a shape-space. We start using a distance measure to discover the similarity between faces and gender difference, using a number of alternatives including geodesic, Euclidean and cosine distance between points on the manifold. For recognition we compare the perfomance distance between Euclidean, cosine and geodesic distance associated with the shape manifold. Here we explore if the distances used to distinguish gender and recognise the same for under different expressions. Also, to explore whether the Fisher-Rao metric can be used to characterise the shape changes due to differences expression and gender difference. We use a 2.5D representation based on facial surface normals (or facial needle-maps) for gender classification and face expression. The needle-map is a shape representation which can be acquired from 2D intensity images using shape-from-shading (SFS). Using the von-Mises Fisher distribution, we compute the elements of the Fisher information matrix, and use this to compute geodesic distance between fields of surface normals to construct a shape-space. We embed the fields of facial surface normals into a lower dimensional pattern space using a number of alternative methods including multidimensional scaling, heat kernel embedding and commute time embedding. We present results on clustering the embedded faces using the BU-3DFEDB, Max Planck and EAR databases. The thesis is divided into five chapters. In Chapter 1 we give a brief introduction and an outline of the thesis. Chapter 2 provides a literature review of aspects related to this topic. More specifically, it starts by describing the relevant literature of face expression recognition and gender difference in computer vision research and the approaches for facial shape recovery. Then, we give a detailed review of the methods developed for face expression and gender difference recognition. Also, we are working with facial shape recovery, we review some relevant techniques including the popular shape-from-shading methods. Are presented in Chapter 3 our first attempt to perform face expression recognition using facial needle maps which is recovered using shape-from-shading. We explore how the different distance measure can be used to measure different facets of shape including gender and expressions. We compute geodesic, euclidean, cosine and Mahalanobis distances for the long-vector representation of the needle-maps for the faces. In Chapter 4 we explore how the Fisher-Rao metric can be used to measure different facets of facial shape estimated from fields of surface normals using von-Mises Fisher (vMF) distribution. In particular we aim to characterise the shape changes due to differences in gender and due to different facial expression. We make use of the vMF distribution since we are dealing with surface normal data over the sphere. The thesis concludes with Chapter 5, where a summary of the contributions of the research work is presented. Also, overall conclusions of the work, as well as, possible future work are discussed.
21
Dunlop, Iain Edward. "Normal and shear forces between surface-grown polyelectrolyte brushes." Thesis, University of Oxford, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.426408.
Full text
22
Vits, Lucia Carolina. "Biochemical Characterization of Normal Navicular Bone Flexor Surface Cartilage." Thesis, Virginia Tech, 2002. http://hdl.handle.net/10919/35755.
Full textAbstract:
Cartilage tissue specimens were obtained from the flexor surface of the navicular bone and distal radiocarpal bone articular surface (controls) from 8 horses 2 to 5 years old. Water, DNA, total collagen, total glycosaminoglycans, chondroitin sulphate, and keratan sulphate contents were determined. The results from each site were compared and the differences were analyzed by paired t-test (P < 0.05).
Significant differences were determined between the water content of the navicular bone flexor surface cartilage (68.32± 3.46 % ) and the distal radiocarpal bone articular surface cartilage (60.60± 4.09%). The total DNA content, total glycosaminoglycan content, total chondroitin sulphate content, and total keratan sulphate for the flexor surface of the navicular bone was: 524.51± 92.89 ng, 0.1533± 0.0338 mg, 0.1018± 0.0197 mg 0.0800± 0.0176 mg, and 0.0092± 0.0037 mg per mg of dry weight cartilage, respectively. The total DNA content, total glycosaminoglycan content, total chondroitin sulphate content, and total keratan sulphate for the distal radiocarpal articular surface cartilage was: 508.80± 70.16 ng, 0.1686± 0.00838 mg, 0.0919± 0.0191, 0.0615± 0.0109 mg, and 0.0074± 0.0029 mg per mg dry weight cartilage, respectively. Not significant differences were determined between these values.
We concluded that the cartilage of the flexor surface of the navicular bone is biochemically similar to hyaline articular cartilage, but differs from previous descriptions of fibrocartilage. Further studies are needed to determine types and proportions of collagen types of the flexor surface of the normal navicular bone. These findings establish a basis of comparison to assess navicular cartilage in aging, disease, and repair.
Master of Science
23
Wu, Jing. "Statistical approaches to gender classification in the surface normal domain." Thesis, University of York, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.516723.
Full text
24
Wang, Yan. "Normal and enhanced raman spectroscopy of carbon electrode surfaces /." The Ohio State University, 1991. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487687959964739.
Full text
25
Xu, Yang. "Normal impact of liquid droplets on smooth solid surfaces." Thesis, Paris Est, 2018. http://www.theses.fr/2018PESC1099/document.
Full textAbstract:
Dans le cadre de la modélisation et de l’expérimentation multi-échelles (projet LabEx MMCD pour les matériaux pour la construction durable) de l’Université Paris-Est Marne-la-Vallée, cette thèse de doctorat vise à modéliser et caractériser les micro-matériaux conçus par impact de gouttelettes de céramique fondue. Les applications de ces matériaux revétus de couches minces sont des traitements de surface pour la construction durable tels que la protection anti-corrosion, les barrières thermiques, le traitement du verre ou les renforts mécaniques. En particulier, nous nous concentrons sur la physique associée à la dynamique des gouttelettes liquides (l'aire de contact et le temps de contact entre la gouttelette et la surface) en effectuant une série de simulations numériques pour les écoulements diphasiques à petite échelle avec le code maison Thetis. Nous avons considéré des variations des conditions d'impact initiales ainsi que l’influence des forces d'inertie, capillaire et visqueuses sur la dynamique des gouttelettes. Nous nous sommes intéressés en particulier au diamètre d'étalement maximal, au temps d’étalement maximal et au temps de contact, sur des surfaces solides de mouillabilité variable. Le code est basé sur l’utilisation d’une méthode Volume-Of-Fluid. Il introduit une fonction auxiliaire régularisée pour estimer la courbure locale et la normale à l'interface. Les principaux liquides de référence adoptés sont l'eau et la céramique fondue, l'eau est choisie pour valider notre code en comparant les simulations aux résultats expérimentaux. La céramique fondue est adoptée car elle est largement utilisée en projection thermique pour créer des barrières thermiques et chimiques (couches anti-oxydantes) ainsi que des renforts mécaniques sur des échantillons spécifiques. Nous nous concentrons sur les cas où les surfaces sont hydrophobes, même si les cas hydrophiles sont également considérés dans les configurations de validation pour des raisons de généralité. Egalement, en introduisant une partie de calcul de l'énergie dans la thèse, une analyse énergétique détaillée de la gouttelette après l'impact est effectuée dans les phases d'étalement et de rétraction pour bien comprendre la dynamique à l'intérieur de la gouttelette. Nous trouvons que le temps de projection est inversement proportionnel à la vitesse d’impact, indépendamment de l’angle de contact lors de l’étalement au temps courts. Une nouvelle mise à l'échelle entre l'étalement maximal et le temps d'étalement est proposée. Celle-ci s'accorde très bien avec les résultats expérimentaux. Par ailleurs, nous introduisons cette mise à l’échelle dans une classe de modèle basée sur la conservation de l’énergie pour prédire l’étalement maximal adimensionné, ce qui permet de mieux prévoir l’étalement maximal adimensionné. Pour finir, une mise à l'échelle du temps de contact est proposée en termes de nombre d'Ohnesorge et de ReynoldsUnder the framework of the LabEx Multi-Scale Modelling and Experimentation of Materials for Sustainable Construction, of Université Paris-Est Marne-La-Vallée, the present PhD thesis aims at modelling and characterizing micro-material designed by impact of molten ceramic droplets. The applications of thin coating materials are surface treatments for sustainable construction such as anti-corrosion, heat barrier, glass treatment or mechanical reinforcement of specific structures.In particular, we focus on the physics behind the liquid droplets' dynamics (the contact area and the contact time between the droplet and surface) by conducting a series of small scale multiphase flow numerical simulations with home-made code Thetis. All simulations are axisymmetric. We have considered variations of initial impact conditions, and studied the influence of inertial, capillary and viscous forces on the droplets' dynamics, especially the maximum spreading diameter, spreading time and the contact time, on solid surfaces. The code is based on Volume-Of-Fluid techniques and introduces an auxiliary smooth function to estimate the local curvature and the normal to the interface. The major reference liquid adopted are the water and the molten ceramic, the water is chosen to validate our code against available experiments at the beginning. The molten ceramic is adopted as it is widely used in thermal spray to built thermal and chemical barriers (anti-oxidant layers) as well as mechanical reinforcements on specific samples. We focus on the cases in which the surfaces are hydrophobic, even if hydrophilic cases are also considered in validation configurations for the sake of generality. Meanwhile, by introducing an energy calculation part in the code, a detailed energetic analysis of the droplet after impact is performed in both the spreading and retraction stage to have a deep understanding of the dynamics inside the droplet.We find the jetting time is inversely proportional to the impact velocity, independent of the contact angle in the early spreading. A new scaling between maximum spreading and spreading time is observed, and agrees well with experimental results. Further, we introduce this scaling into the model based on energy conservation to predict the maximum spreading factor, which provides better prediction on maximum spreading factor than existing literature references. Also a scaling of contact time is proposed in terms of Ohnesorge number and Reynolds number
26
Junique, Stéphane. "Surface-normal multiple quantum well electroabsorption modulators based on GaAs-related materials." Licentiate thesis, KTH, Microelectronics and Information Technology, IMIT, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-292.
Full text
27
Adams, Brandy Rogers. "Ceramic materials mimicking normal bone surface microstructure and chemistry modulate osteoblast response." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/50292.
Full textAbstract:
Bone consists of collagen/hydroxyapatite (HA) composites in which poorly crystalline carbonated calcium phosphate is intercalated within the fibrillar structure. Normal bone mineral is a carbonated-apatite, but there are limited data on the effect of mineral containing carbonate on cell response. Although the exact biological role of silicate in bone formation is unclear, silicate has been identified at trace levels in immature bone and is believed to play a metabolic role in new bone formation. To mimic the inorganic and organic composition of bone we have developed a variety of bone graft substitutes. In the present body of research, we characterized the surface composition of human cortical and trabecular bone. When then characterized the surface compositions of the following potential bone substitutes: carbonated hydroxyapatite (CO₃²-HA), silicated hydroxyapatite (Si-HA), and collagen sponges mineralized with calcium phosphate using the polymer-induced liquid-precursor (PILP) process. In the latter substitutes, the PILP process leads to type I collagen fibrils infiltrated with an amorphous mineral precursor upon which crystallization leads to intrafibrillar HA closely mimicking physiological bone mineral. We then determined the osteoblast-like cell response to each bone substitute to characterize the substrate’s effect on osteoblast differentiation. The observations collectively indicate that cells are sensitive to the formatting of the mineral phase of a bone substitute and that this format can be altered to modulate cell behavior.
28
Akéké, Eric Dago. "Classification des singularités minimales de surfaces normales par les discriminants génériques." Aix-Marseille 1, 2005. http://www.theses.fr/2005AIX11030.
Full textAbstract:
La thèse porte sur les discriminants génériques des singularités de surface analytique complexe normale. Nous rappelons d'abord des résultats bien connus de la théorie des singularités de surfaces normales, en particulier des singularités rationnelles de surfaces. Nous montrons ensuite que pour une famille analytique des singularités de surfaces normales pour lesquelles les discriminants génériques sont équisinguliers, on a les conditions de Whitney. Après avoir rappelé d'après R. Bondil les structures algébriques des discriminants génériques des singularités minimales de surfaces (une sous-classe des singularités rationnelles), nous donnons une preuve combinatoire du lien entre les arbres-limites (introduites par De Jong et Van Straten) et les discriminants génériques des singularités minimales de surfaces normales. On peut donner à partir de ces arbres, des exemples de singularités de surfaces de même discriminant générique et de type topologique distinct.
29
Li, Boren. "Photometric stereo for micro-scale shape reconstruction." Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/75021.
Full textAbstract:
This dissertation proposes an approach for 3D micro-scale shape reconstruction using photometric stereo (PS) with surface normal integration (SNI). Based on the proposed approach, a portable cost-effective stationary system is developed to capture 3D shapes in the order of micrometer scale. The PS with SNI technique is adopted to reconstruct 3D microtopology since this technique is highlighted for its capability to reproduce fine surface details at pixel resolution. Furthermore, since the primary hardware components are merely a camera and several typical LEDs, the system based on PS with SNI can be made portable at low cost.
The principal contributions are three folds. First, a PS method based on dichromatic reflectance model (DRM) using color input images is proposed to generalize PS applicable to a wider range of surfaces with non-Lambertian reflectances. The proposed method not only estimates surface orientations from diffuse reflection but also exploits information from specularities owing to the proposed diffuse-specular separation algorithm. Using the proposed PS method, material-dependent features can be simultaneously extracted in addition to surface orientations, which offers much richer information in understanding the 3D scene and poses more potential functionalities, such as specular removal, intrinsic image decomposition, digital relighting, material-based segmentation, material transfer and material classification.
The second contribution is the development of an SNI method dealing with perspective distortion. The proposed SNI is performed on the image plane instead of on the target surface as did by orthographic SNI owing to the newly derived representation of surface normals. The motivation behind the representation is from the observation that spatially uniform image points are simpler for integration than the non-uniform distribution of surface points under perspective projection. The new representation is then manipulated to the so-called log gradient space in analogy to the gradient space in orthographic SNI. With this analogy, the proposed method can inherit most past algorithms developed for orthographic SNI. By applying the proposed SNI, perspective distortion can be efficiently tackled with for smooth surfaces. In addition, the method is PS-independent, which can keep the image irradiance equation in a simple form during PS.
The third contribution is the design and calibration of a 3D micro-scale shape reconstruction system using the derived PS and SNI methods. This system is originally designed for on-site measurement of pavement microtexture, while its applicability can be generalized to a wider range of surfaces. Optimal illumination was investigated in theory and through numerical simulations. Five different calibrations regarding various aspects of the system were either newly proposed or modified from existing methods. The performances of these calibrations were individually evaluated. Efficacy of the developed system was finally demonstrated through comprehensive comparative studies with existing systems. Its capability for on-site measurement was also confirmed.Ph. D.
30
Medeiros, Débora de Oliveira [UNESP]. "Tratamento numérico da condição de tensão normal para métodos de projeção em escoamentos com superfície livre." Universidade Estadual Paulista (UNESP), 2017. http://hdl.handle.net/11449/150908.
Full textAbstract:
Submitted by Debora de Oliveira Medeiros null (deboraomedeiros@gmail.com) on 2017-06-13T19:08:30Z
No. of bitstreams: 1
dissertacao_arquivar.pdf: 4524135 bytes, checksum: 33a027db23ff40bebc026b9090443d53 (MD5)Approved for entry into archive by Luiz Galeffi (luizgaleffi@gmail.com) on 2017-06-19T12:58:15Z (GMT) No. of bitstreams: 1 medeiros_do_me_prud.pdf: 4524135 bytes, checksum: 33a027db23ff40bebc026b9090443d53 (MD5)
Made available in DSpace on 2017-06-19T12:58:15Z (GMT). No. of bitstreams: 1 medeiros_do_me_prud.pdf: 4524135 bytes, checksum: 33a027db23ff40bebc026b9090443d53 (MD5) Previous issue date: 2017-04-24
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Neste trabalho é apresentado um estudo das equações de Navier Stokes incompressível com superfície livre e métodos de projeção com uma formulação recente denominada laplaciano superficial. Esta formulação tem como finalidade uma melhor descrição da força de tensão superficial e grandezas, como curvatura e vetores tangencial e normal, descritas sobre a interface. Assim, uma condição de tensão normal alternativa é definida, e esta quando discretizada implicitamente e combinada com o método de projeção, descrevem a formulação laplaciano superficial, cuja sua solução é utilizada como condições de contorno para resolver o sistema de equações que descrevem o escoamento. A nova formulação destina-se a resolver um sistema tridiagonal de equações gerado sobre a interface, e usar a solução deste sistema de equações como uma condição de contorno na superfície livre para o sistema linear da correção da pressão no interior do domínio, que é resultante da aplicação do método de projeção. A nova equação que define a condição de tensão normal conta com grandezas definidas na malha euleriana, no contexto Marker-And-Cell (MAC), que devem ser projetadas sobre a malha lagrangeana e também considera a curvatura e os vetores tangente e normal na sua descrição, sendo importante um estudo detalhado de geometria diferencial. Finalmente, variações da formulação laplaciano superficial com tensão superficial para diferenças finitas são aplicadas para resolver os testes numéricos da oscilação da gota e da gota apoiada que possuem solução de referência, além da simulação de um problema com movimento de interface (fountain flow). Nestes testes, concluímos que a variação mais precisa e estável é aquela que aplica uma discretização da equação da tensão normal utilizando médias de valores alocados na malha MAC.
This work presents a study of the Navier-Stokes equations incompressible with free surface and a projection methods with a recent formulation defined as surface laplacian. The purpose of this formulation is to improve the description of the force of stress tension and quantities, as curvature and tangent and normal vectors, present at the interface. Thus, an alternative normal stress condition is defined, and when this is discretized implicitly and combined with the employ of projection method, describe the surface laplacian formulation, whose solution is used as boundary condition to solve the system of equations describing the flow. The new formulation is intended to solve the tridiagonal system of equations generated at the interface, and to use this solution as a boundary condition at free surface for the linear system of the pressure correction inside of domain, which results of the application of the projection method. The new equation used to define the normal stress condition considers quantities defined in the Eulerian mesh, in the Marker-And-Cell context (MAC), that should be projected on the Lagrangian mesh. In addition, in the new equation, it is also considered the influence of the curvature and normal and tangential vectors in your description, so that a detailed study of differential geometry for this computation is important. Finally, variations of the surface laplacian formulation for finite differences are applied for solving numerical tests of the drop oscillation and sessile drop which have reference solutions, beyond of the simulation of a problem with free surface moving (fountain flow). In these tests, we concluded that the most accurate and stable variation is the one that applies a discretization of the normal stress equation using the mean of values in the MAC mesh.
FAPESP: 2015/01243-0
31
Hodiak, Justin Hannah. "Design of fiber-coupled surface-normal fabry perot electroabsorption modulators for analog applications /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 1999. http://wwwlib.umi.com/cr/ucsd/fullcit?p9936831.
Full text
32
Pare, Christopher J. "Perceptual analysis of voice change associated with surface electrical stimulation in normal speakers." Tallahassee, Fla. : Florida State University, 2009. http://purl.fcla.edu/fsu/lib/digcoll/undergraduate/honors-theses/244573.
Full textAbstract:
Thesis (Honors paper)--Florida State University, 2009.Advisor: Dr. Richard J. Morris, Florida State University, College of Arts and Sciences, Dept. of Biology. Includes bibliographical references.
33
Öhrn, Kristina. "Different Mapping Techniques for Realistic Surfaces." Thesis, University of Gävle, Department of Mathematics, Natural and Computer Sciences, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-612.
Full textAbstract:
The different mapping techniques that are used increases the details on surfaces without increasing the number of polygons. Image Based Sculpting tools in the program Modo and Z-Brush is used to create folds and wrinkles from photographs of actual fabrics instead of trying to create these shapes by modeling them. This method makes it easier to achieve photorealistic renderings and produce as realistic fabric dynamics as possible when they are applied on objects.
34
Ding, Yi. "Obtaining 3D malgnant melanoma indicators through the analysis of surface normals from photometric stereo." Thesis, University of the West of England, Bristol, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.490447.
Full textAbstract:
Cutaneous Malignant Melanoma (MM) is a life-threatening skin cancer, the successful treatment of which relies heavily on early diagnosis. Overall the last 30 years, the incidence rates of MM have increased more than any other cancer in the UK. The ABCD heuristic rules have been used conventionally as an aid to consultants to differentiate between benign lesions and MMs. However, due to the complexity of the problem caused by large variety of dermatological diseases and various forms of MM, the existing 2D ABCD features have been found to be inadequate in reliably detecting MMs. Motivated by the observations that disruptions in skin texture patterns are larger for MMs than benign lesions, this work investigates the feasibility of lesion classification using 3D skin surface texture features, in the form of 3D skin surface disruptions. This is considered to have the potential of establishing new and independent MM indicators m addition to the existing ID ones.
35
Lin, Yiqiang Farouk Bakhtier. "Acoustic wave induced convection and transport in gases under normal and micro-gravity conditions /." Philadelphia, Pa. : Drexel University, 2007. http://hdl.handle.net/1860/1795.
Full text
36
Massart, Daniel. "Normes stables des surfaces." Phd thesis, Ecole normale supérieure de lyon - ENS LYON, 1996. http://tel.archives-ouvertes.fr/tel-00589624.
Full textAbstract:
On étudie la norme stable sur l'homologie des variétés riemanniennes, plus spécialement dans le cas où la variété est une surface orientable de genre supérieur à 1. On établit le lien entre norme stable et fonction beta de Mather, puis on montre des résultats de non-stricte convexité et non-différentiabilité de la norme stable. Ensuite on compare la norme stable et la norme L2.
37
Magnusson, Martin. "The three-dimensional normal-distributions transform : an efficient representation for registration, surface analysis, and loop detection." Doctoral thesis, Örebro universitet, Akademin för naturvetenskap och teknik, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-8458.
Full textAbstract:
This dissertation is concerned with three-dimensional (3D) sensing and 3D scan representation. Three-dimensional records are important tools in several disciplines; such as medical imaging, archaeology, and mobile robotics. This dissertation proposes the normal-distributions transform, NDT, as a general 3D surface representation with applications in scan registration, localisation, loop detection, and surface-structure analysis. After applying NDT, the surface is represented by a smooth function with analytic derivatives. This representation has several attractive properties. The smooth function representation makes it possible to use standard numerical optimisation methods, such as Newton’s method, for 3D registration. This dissertation extends the original two-dimensional NDT registration algorithm of Biber and Straßer to 3D and introduces a number of improvements. The 3D-NDT scan-registration algorithm is compared to current de facto standard registration algorithms. 3D-NDT scan registration with the proposed extensions is shown to be more robust, more accurate, and faster than the popular ICP algorithm. An additional benefit is that 3D-NDT registration provides a confidence measure of the result with little additional effort. Furthermore, a kernel-based extension to 3D-NDT for registering coloured data is proposed. Approaches based on local visual features typically use only a small fraction of the available 3D points for registration. In contrast, Colour-NDT uses all of the available 3D data. The dissertation proposes to use a combination of local visual features and Colour-NDT for robust registration of coloured 3D scans. Also building on NDT, a novel approach using 3D laser scans to perform appearance-based loop detection for mobile robots is proposed. Loop detection is an importantproblem in the SLAM (simultaneous localisation and mapping) domain. The proposed approach uses only the appearance of 3D point clouds to detect loops and requires nopose information. It exploits the NDT surface representation to create histograms based on local surface orientation and smoothness. The surface-shape histograms compress the input data by two to three orders of magnitude. Because of the high compression rate, the histograms can be matched efficiently to compare the appearance of two scans. Rotation invariance is achieved by aligning scans with respect to dominant surface orientations. In order to automatically determine the threshold that separates scans at loop closures from nonoverlapping ones, the proposed approach uses expectation maximisation to fit a Gamma mixture model to the output similarity measures. In order to enable more high-level tasks, it is desirable to extract semantic information from 3D models. One important task where such 3D surface analysis is useful is boulder detection for mining vehicles. This dissertation presents a method, also inspired by NDT, that provides clues as to where the pile is, where the bucket should be placed for loading, and where there are obstacles. The points of 3D point clouds are classified based on the surrounding surface roughness and orientation. Other potential applications include extraction of drivable paths over uneven surfaces.
38
Hastie, C. L. "Differential protein expression on the cell surface of normal epithelial and prostate cancer cells." Thesis, University College London (University of London), 2007. http://discovery.ucl.ac.uk/1445546/.
Full textAbstract:
Prostate cancer is the most frequently diagnosed cancer in men in Western countries. Clinically localized disease can be cured with surgery or radiotherapy, but once the disease has advanced or spread, there are no curative treatments. The aim of this thesis is to compare protein expression in a pair of normal epithelial and prostate cancer cells derived from the same patient and to determine the effect of interferon y on this expression pattern. Proteins that are differentially expressed or change in expression in response to y interferon might be of clinical value as biomarkers or therapeutic targets. Biotin labelling followed by avidin chromatography was used to obtain membrane protein enriched lysates from a pair of cell lines derived from normal epithelium (1542 NPX) and prostate cancer (1542 CP3TX) from the same patient. These proteins were resolved and identified using SDS PAGE, coomassie staining and mass spectrometry. The same protocol was used to identify proteins differentially expressed on stimulation with interferon y. The proteins identified were subject to further analysis, particularly annexin II (All), which was interferon-regulated. The expression of this protein was down regulated in the cancer cell line within four hours of interferon y stimulation. This expression pattern was found to be cell surface specific as the total cellular expression of All remained unchanged, as confirmed by immunofluorescence. All down regulation also reduced the invasive potential of the cancer cells. Re-introduction of All into LNCaP cells, which do not express the protein, led to an increase in their invasive capacity. The mechanism regulating this cell surface specific effect was explored. It was discovered that inhibition of the ATP binding cassette transporter ABCA1 prevented surface AH expression. Protection of ABCA1 from calpain mediated degradation, maintained AH expression even in the presence of interferon y. These findings led to the development of a model of interferon y action on All involving phosphorylation of ABCA1 as a signal for targeted degradation by calpain II.
39
Siu, Hiu-fai, and 蕭曉暉. "Quantitative lumbar surface EMG topographic analysis: comparison between normal and low back pain patients." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B4327870X.
Full text
40
Seck, Alassane. "3D surface texture analysis of high resolution normal fields for facial skin condition assessment." Thesis, Aberystwyth University, 2016. http://hdl.handle.net/2160/d3544edf-bcd2-4af1-85af-f125cba675f7.
Full textAbstract:
In this thesis, we introduce new methods for analysing three dimensional surface texture using high resolution normal fields and apply these to the detection and assessment of skin conditions in human faces, specifically wrinkles, pores and acne. The thesis is part of a project sponsored by Unilever with an interest in applying the outcome of the research to facial skin care product development. This explains our focus on facial skin conditions. The main contributions of this thesis are the introduction of three methods of extracting texture descriptors from high resolution surface orientation fields, a comparative study of two-dimensional and three-dimensional skin texture analysis and the collection of an extensive dataset of high resolution 3D facial scans presenting various skin conditions. The dataset includes human rating judgements on the presence of certain skin conditions. Computer aided skin condition assessment has been mostly addressed using two dimensional texture analysis techniques on skin images or coarse geometrical features extracted from the skin’s three dimensional macro structures. While the first trend ignores the three dimensional nature characterising most of the skin conditions, the latter mainly deals with geometrical features that are not fine enough to capture skin structures at the meso and micro scales. Advances in three dimensional surface imaging during the last few decades brings the possibility of capturing human skin’s fine geometrical structures and re- flectance properties with unprecedented quality and resolution (down to the level ii of the pores). The methods proposed in this work aim at leveraging these advances and revisit the formulation of texture analysis as a three dimensional problem. For data collection we set up a Lightstage to capture high resolution facial normal fields along with reflectance properties. The collected data are photo-realistically rendered and presented to the general public for annotations indicating the presence of the studied skin conditions. These constitute the ground truth on which we apply the proposed methods and learn models for detecting and assessing facial skin conditions. We also demonstrate that some of these three dimensional surface texture descriptors can be extended to synthesize highly detailed skin structures and simulate the studied skin condition on normal faces.
41
Siu, Hiu-fai. "Quantitative lumbar surface EMG topographic analysis comparison between normal and low back pain patients /." Click to view the E-thesis via HKUTO, 2009. http://sunzi.lib.hku.hk/hkuto/record/B4327870X.
Full text
42
Rissmann, Clinton Francis. "Using Surface Methods to Understand the Ohaaki Hydrothermal Field, New Zealand." Thesis, University of Canterbury. Geological Sciences, 2010. http://hdl.handle.net/10092/5027.
Full textAbstract:
After water vapour, CO₂ is the most abundant gas associated with magmatic hydrothermal systems. The
detection of anomalous soil temperature gradients, and/or a significant flux of magmatic volatiles, is
commonly the only surface signature of an underlying high temperature reservoir. For both heat (as water
vapour) and gas to ascend to the surface, structural permeability must exist, as the unmodified bulk
permeability of reservoir rock is too low to generate the focussed fluid flow typical of magmatic
hydrothermal systems. This thesis reports the investigation into the surface heat and mass flow of the
Ohaaki hydrothermal field using detailed surface measurements of CO₂ flux and heat flow. Detailed
surface measurements form the basis of geostatistical models that quantify and depict the spatial
variability of surface heat and mass flow, across the surface of both major thermal areas, as high
resolution pixel plots. These maps, in conjunction with earlier heat and mass flow studies, enable: (i)
estimates of the pre-production and current CO₂ emissions and heat flow for the Ohaaki Field; (ii)
interpretation of the shallow permeability structures governing fluid flow, and; (iii) the spatial
relationships between pressure-induced ground subsidence and permeability.
Heat flow and CO₂ flux surveys indicate that at Ohaaki the soil zone is the dominant (≥ 70% and up to
99%) pathway of heat and mass release to the atmosphere from the underlying hydrothermal reservoir.
Modelling indicates that although the total surface heat and mass flow at Ohaaki is small, it is highly
focused (i.e., high volume per unit area) relative to other fields within the Taupo Volcanic Zone (TVZ).
Normalised CO₂ emissions are comparable to other volcanic and hydrothermal fields both regionally and
globally. Despite 20 years of production, there is little difference between pre-production and current CO₂
emission rates. However, the similarity of CO₂ emission rates masks a 40% increase in CO₂ emissions
from new areas of intense steaming ground that have developed in response to production of the field for
electrical energy production. This increase in thermal ground emissions is offset by emission losses
associated with the drying up of all steam heated pools and alkali-Cl outflows from the Ohaaki West
(OHW) thermal area, in response to production-induced pressure decline. The location of surface thermal
areas is governed by the occurrence of buried or partially emergent lava domes, whereas the magnitude of
CO₂ flux, mass flow, and heat flow occurring within each thermal area is determined by the proximity of
each dome (thermal areas) to major upflow zones.
Buried or partially emergent silicic lava domes act as cross-stratal pathways for fluid flow, connecting the
underlying reservoir to the surface, and bypassing several hundred metres of the poorly permeable Huka
Falls Formation (HFF) caprock. For each dome complex the permeable structures governing fluid flow
are varied. At Ohaaki West, thermal activity is controlled by a deep-rooted concentric fracture zone,
developed during eruption of the Ohaaki Rhyolite dome. Within the steam-heated Ohaaki East (OHE)
thermal area, flow is controlled by a high permeability fault damage zone (Broadlands Fault) developed
within the apex of the Broadlands Dacite dome. Structures controlling alkali-Cl fluid flow at OHW also
iii
appear to control the occurrence and shape of major subsidence bowls (e.g., the Main Ohaaki Subsidence
Bowl), the propagation of pressure decline to surface, and the development and localization of pore fluid
drainage. Across the remainder of the Ohaaki field low amplitude ground subsidence is controlled by the
extent of aquifer and aquitard units that underlie the HFF, and proximity to the margins of the hot water
reservoir. The correlation between the extent of low amplitude ground subsidence and the margins of the
field reflects the coupled relationship between the hot water reservoir and reservoir pressure. Only where
thick vapour-phase zones buffer the vertical propagation of deep-seated pressure decline to the surface
(i.e., OHE thermal area), is ground subsidence not correlated with subvertical structural permeability
developed within the HFF.
This thesis makes contributions to regional and global research on geothermal and hydrothermal systems
by: (i) quantifying the origin, mass, and upward transport of magmatic carbon from geothermal
reservoirs; (ii) assessing the changes to the natural surface heat and mass flow of the Ohaaki Field
following 20 years of production; (iii) establishing the utility of surface CO₂ flux and heat flow surveys to
identify major upflow zones, estimate minimum mass flow, and determine the enthalpy of reservoirs; (iv)
providing insight into the hydrothermal, structural and lithological controls over hydrothermal fluid flow;
(v) demonstrating the influence of extinct silicic lava domes as important structural elements in the
localisation of hydrothermal fluid flow; (vi) identifying the hydrostructural controls governing the spatial variability in the magnitude of pressure-induced ground subsidence, from which predictive models of subsidence risk may be defined, and; (vii) developing new technologies and characterising methods used for detailed assessment of surface heat and mass flow.
43
Tombari, Francesca. "Deformation of surfaces in 2D persistent homology." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018. http://amslaurea.unibo.it/15809/.
Full textAbstract:
In the context of 2D persistent homology a new metric has been recently introduced, the coherent matching distance. In order to study this metric, the filtering function is required to present particular “regularity” properties, based on a geometrical construction of the real plane, called extended Pareto grid. This dissertation shows a new result for modifying the extended Pareto grid associated to a filtering function defined on a smooth closed surface, with values in the real plane. In future, the technical result presented here could be used to prove the genericity of the regularity conditions assumed for the filtering function.
44
Durgun, Ahmet Cemal. "Computation Of Radar Cross Sections Of Complex Targets By Physical Optics With Modified Surface Normals." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12609810/index.pdf.
Full textAbstract:
In this study, a computer code is developed in MATLAB®to compute the Radar Cross Section (RCS) of arbitrary shaped complex targets by using Physical Optics (PO) and Modified PO. To increase the computational efficiency of the code, a novel fast integration procedure for oscillatory integrals, called Levin&rsquo
s integration, is applied to PO integrals. In order to improve the performance of PO near grazing angles and to model diffraction effects, a method called PO with Modified Surface Normal Vectors is implemented. In this method, new surface normals are defined to model the diffraction mechanism. Secondary scattering mechanisms like multiple scattering and shadowing algorithms are also included into the code to obtain a complete RCS prediction tool. For this purpose, an iterative version of PO is used to account for multiple scattering effects. Indeed, accounting for multiple scattering effects automatically solves the shadowing problem with a minor modification. Therefore, a special code for shadowing problem is not developed. In addition to frequency domain solutions of scattering problems, a waveform analysis of scattered fields in time domain is also comprised into this thesis. Instead of direct time domain methods like Time Domain Physical Optics, a Fourier domain approach is preferred to obtain the time domain expressions of the scattered fields. Frequency and time domain solutions are obtained for some simple shapes and for a complex tank model for differently polarized incident fields. Furthermore, a statistical analysis for the scattered field from the tank model is conducted.
45
Yadav, Sunil Kumar [Verfasser]. "Surface Denoising based on The Variation of Normals and Retinal Shape Analysis / Sunil Kumar Yadav." Berlin : Freie Universität Berlin, 2018. http://d-nb.info/1171431228/34.
Full text
46
Ujir, Hamimah. "3D facial expression classification using a statistical model of surface normals and a modular approach." Thesis, University of Birmingham, 2013. http://etheses.bham.ac.uk//id/eprint/4371/.
Full textAbstract:
Following the success in 3D face recognition, the face processing community is now trying to establish good 3D facial expression recognition. Facial expressions provide the cues of communication in which we can interpret the mood, meaning and emotions at the same time. With current advanced 3D scanners technology, direct anthropometric measurements (i.e. the comparative study of sizes and proportions of the human body) are easily obtainable and it offers 3D geometrical data suitable for 3D face processing studies. Instead of using the raw 3D facial points, we extracted its derivative which gives us 3D facial surface normals. We constructed a statistical model for variations in facial shape due to changes in six basic expressions using 3D facial surface normals as the feature vectors. In particular, we are interested in how such facial expression variations manifest themselves in terms of changes in the field of 3D facial surface normals. We employed a modular approach where a module contains the facial features of a distinct facial region. The decomposition of a face into several modules promotes the learning of a facial local structure and therefore the most discriminative variation of the facial features in each module is emphasized. We decomposed a face into six modules and the expression classification for each module is carried out independently. We constructed a Weighted Voting Scheme (WVS) to infer the emotion underlying a collection of modules using a weight that is determined using the AdaBoost learning algorithm. Using our approach, using 3D facial surface normal as the feature vector of WVS yields a better performance than 3D facial points and 3D distance measurements in facial expression classification using both WVS and Majority Voting Scheme (MVS). The attained results suggest surface normals do indeed produce a comparable result particularly for six basic facial expressions with no intensity information.
47
Ugolini, Matteo. "K3 surfaces." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/18774/.
Full text
48
Norman, Jessica K. "Perceptual analysis of voice change associated with surface electrical stimulation in normal speakers sentence data /." Tallahassee, Fla. : Florida State University, 2010. http://purl.fcla.edu/fsu/lib/digcoll/undergraduate/honors-theses/2181937.
Full textAbstract:
Thesis (Honors paper)--Florida State University, 2010. Includes bibliographical references.Advisor: Dr. Richard J. Morris, Florida State University, College of Arts and Sciences, Dept. of Communication Science and Disorders.
49
Hedley, Susan Jennifer. "Investigation of pigmentation and immune-related cell surface molecules in cultured normal and vitiligo melanocytes." Thesis, University of Sheffield, 1999. http://etheses.whiterose.ac.uk/3483/.
Full textAbstract:
Vitiligo is an acquired idiopathic hypomelanotic disorder which has an unknown aetiology and ultimately affects melanocytes, primarily of the skin. Many patients with vitiligo suffer from psychological distress and therefore it is important to determine why melanocytes are destroyed. The aim of this study was to learn more about the basic cellular physiology of normal and vitiligo melanocytes. Morphology, proliferation and pigmentation in normal melanocytes were highly influenced by media additives, bovine pituitary extract (BPE), cholera toxin (CT), foetal calf serum (FCS) and phorbol 12-myristate 13 acetate (PMA). In the absence of these factors, extracellular matrix (ECM) proteins increased survival, proliferation and pigmentation of normal melanocytes, while ultraviolet irradiation (UVR) increased dendricity and pigmentation in the presence of these factors. Normal and vitiligo melanocytes were morphologically very similar and long-term cultured vitiligo melanocytes had proliferation which was not significantly different to that of normal melanocytes. Constitutive and cytokine-stimulated expression of intercellular adhesion molecule-1 (ICAM-1), major histocompatibility complex (MHC) class I and II were not different between normal and vitiligo melanocytes in vitro. The latter suggested that vitiligo melanocytes do not have an inherent defect in regulation of these adhesion molecules which could lead to their premature interaction with the immune system. a-melanocyte stimulating hormone (a-MSH) has a controversial pigmentary role in man. In normal melanocytes, only under a limited number of media conditions did melanocytes exhibit increased melanogenesis to a-MSH. However a-MSH was found to be particularly effective at opposing the actions of TNF-a-stimulated ICAM-1 expression in melanocytes. This finding supported an immunomodulatory role for a-MSH in normal melanocytes. Finally a surgical treatment using cultured epithelial autograis (CEA) was used to treat 3 patients with symmetrical (generalised) vitiligo, with mixed results. One patient showed good repigmentation, while the response was less promising in the other-two patients.
50
Naik, Raj. "Investigations of cell surface oligosaccharides in normal vulval epithelium and in preinvasive/invasive vulval lesions." Thesis, University of Newcastle Upon Tyne, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.360742.
Full text