Placoderms appeared in the Silurian period and rapidly evolved and dominated the waters during the Devonian period. Among the earliest of the placoderms are yunnanolepids, a primitive form of antiarch from the Early Devonian of China and Vietnam. Very little work has so far been devoted to this family, and previous descriptions are based on conventional preparation methods. We can now take a closer look at a yunnanolepid specimen with the help of three dimensional modelling based on a synchrotron X-ray microtomographic scan series. The well preserved anterior ventrolateral plate exhibits an opening for the pectoral fin, clearly visible structures, and outer ornamentation. A first 3D image of the mysterious hollow called Chang’s apparatus has been constructed. Chang’s apparatus has only ever been seen in Yunnanolepididae, but never described in detail, and its function remains unknown. The trunk plate has captured settling sediment and in the inwash can be found tooth plates and scales of other gnathostomes. Among these are two well preserved anterior ventrolateral plates of young antiarchs. No ornamentation can be seen on the juveniles and their postbranchial lamina had not yet developed. / Placodermer (pansarhajar) är en grupp tidiga käkförsedda fiskar som dök upp under tidig silur. De spred sig snabbt under silur och dominerade världens vatten under devon, för att helt dö ut i slutet av devon. En av de allra tidigaste grupperna av placodermer är en grupp som kallas yunnanolepider, de var en primitiv form av antiarcher (armpansarhajar) från tidig devon i Kina och Vietnam. Man vet väldigt lite om denna grupp, och alla tidigare beskrivningar har baserats på konventionella prepareringsmetoder där man mekaniskt avlägsnat sediment som omgav fossilet. Här har ett fossil beskrivits med hjälp av röntgenbaserad mikrotomografi som sedan modellerats digitalt. Modellen visar en välbevarad bröstplåt, del av skuldergördelen, från yunnanolepiden. Denna visar en öppning med fäste för bröstfenan, interna strukturer och yttre ornamentering. Man kan här få en första syn på en intern hålighet som kallas Chang’s apparatus som aldrig tidigare har beskrivits i detalj. I sedimentet som samlats i bröstplåten kan man även se delar av andra organismer, såsom en tandplatta och fjäll. Bland dessa bitar finns två välbevarade bröstplåtar från juvenila antiarcher.

La réalité augmentée (RA) mobile consiste à faire coexister en temps-réel des mondes virtuel et réel. La mobilité est facilitée par l'utilisation de nouveaux dispositifs de types smartphones, et mini-PC embarquant un certain nombre de capteurs (visuels, inertiels,…). Ces dispositifs disposent toutefois d'une puissance de calcul limitée, qui peut s'avérer critique au vu des applications envisagées. L'une des solutions est de recourir à des mécanismes de distributions pour répartir les calculs sur un ensemble hétérogène de machines (serveurs ou autre terminaux mobiles). L'objectif de cette thèse est de concevoir une architecture logicielle dédiée à la réalité augmentée distribuée et plus particulièrement aux applications distribuées capable de fonctionner sur des réseaux ad-hoc constitués de terminaux hétérogènes déployées au travers d'un réseau dans un premier temps. Dans un deuxième temps, il conviendra de démontrer l'applicabilité de la solution proposée à des applications concrètes et d'explorer différentes possibilités d'exploitation originales de la distribution dans les applications de Réalité Augmentée en mettant l'accent sur la plus value apportée en terme de fonctionnalités ou d'opérations possibles en comparaison avec une solution de Réalité Augmentée classique (non distribuée) et en comparaison avec les performances des environnements dédiés à la RA existants offrant la possibilité de créer des applications distribuées. / Mobile Augmented Reality (AR) consists in achieving to make co-existing virtual and real worlds in real time. Mobility is made easier by the use of new devices such as smartphones and wearable computers or smart objects (ex. Glasses) involving sensors (inertial, visual...). These devices have lower computation capabilities that can be critical to some Augmented Reality applications. One of the solutions is to use distribution mechanisms to distribute processing on several and heterogeneous machines. The goal of this thesis is to design a software architecture dedicated to distributed Augmented Reality and more precisely to distributed applications that can run on ad-hoc networks including heterogeneous terminals deployed in a network. The second part of the thesis is to prove the feasibility and the efficiency of the proposed architecture on real AR applications and explore different original uses of distribution for AR applications. Focusing on the added value in terms of features and possible opérations compared to non-distributed AR applications and compared to existing frameworks offering distributed AR components.

No description available.

Cette thèse CIFRE a pour objet d'explorer, de développer et d'exploiter le potentiel des outils de représentation et de modélisation 3D dans l'étude géomorphologique du karst dont la structure géométrique est intrinséquement en trois dimensions. Ce travail a pour support d'étude les gorges de l'Ardèche dont l'évolution géomorphologique et paléogéographique, tant aux temps géologiques qu'aux temps des hommes, est extrêmement riche. Ce territoire propose en outre des défis scientifiques mais aussi sociétaux depuis la découverte de la désormais célèbre grotte Chauvet et la mise en place de l'ERGC (Espace de Restitution de la Grotte Chauvet). C'est dans ce cadre qu'une méthodologie de recherche appliqué au domaine souterrain a été élaborée et appliquée à l'étude de la grotte Chauvet et des cavités des gorges de l'Ardèche pour (i) l'étude de la spéléogenèse et de la karstogenèse, (ii) l'évolution géomorphologique d'une grotte ornée (grotte Chauvet) et (iii) la réalisation d'un projet culturel : l'ERGC. La première partie (chapitre 1, 2 et 3) présente les verrous actuels en géomorphologie karstique, la méthodologie de recherche développée et les apports de la connaissance géomorphologique de la grotte Chauvet et de l'utilisation de modèles 3D dans la construction d'un fac-similé de grande envergure. La deuxième partie (chapitre 4, 5 et 6) présente les problématiques et les résultats de l'étude géomorphologique 3D des gorges de l'Ardèche et des cavités environnantes. Les principaux apports se situent dans la connaissance des formes élémentaires du karst et la géométrie des réseaux karstiques. Ceci a permis d'élaborer un scénario global d'évolution paléogéographique de ce secteur depuis le Néogène jusqu'à l'Actuel. Enfin la troisième partie (chapitre 7, 8 et 9) aborde les problématiques d'étude et de recherches spécifiques des grottes ornées et de leur fermeture. La grotte Chauvet et sa zone d'entrée font l'objet d'une analyse détaillée permettant de répondre aux questionnements pluridisciplinaires (archéologie, préhistoire, conservation, valorisation …). L'approche géomorphologique 3D développée pour répondre aux différentes problématiques des sciences de la Nature et des Hommes est ici posée et discutée. / This doctoral thesis aims to explore, develop and exploit the potential of 3D visualization tools and 3D modelling for research on karst morphology and geometry, intrinsically three-dimensional landscape features. This work is based on research in the gorges of the Ardeche region where geomorphological formations and paleogeographic changes are rich and varied, over both geological and human time frames. Since Chauvet Cave's discovery and the establishment of the ERGC (‘Espace de Restitution de la Grotte Chauvet'), this region has presented scientific as well as societal challenges. It is in this context, and in accordance with specificities of the subterranean condition of this karst environment, that 3D visualization and mapping tools were developed and applied at Chauvet Cave and at several other nearby Ardèche canyon caves. The aims of this research were to: (i) Study the speleogenesis and karstogenesis of the cave systems. (ii) Study the geomorphological evolution of a decorated cave (Chauvet Cave). (iii) Advise construction of the facsimile of Chauvet Cave (ERGC project). The first part of this thesis (Chapters 1, 2 and 3) discusses the challenges associated with research on karst geomorphology; the methodology employed to address those challenges; and the contribution of geomorphological knowledge and the usefulness of 3D modelling towards the construction of a facsimile of Chauvet Cave. The second part (Chapters 4, 5 and 6) presents the results of the 3D geomorphological study of the cave systems in the vicinity of the Ardèche canyon. These major results bring new knowledge of karst morphologies and geometric networks that enable a new palaeo-geographic model of landscape evolution since the Neogene to the present. The third and final part of the thesis (Chapters 7, 8 and 9) focuses on research in the prehistoric cave of Chauvet (including its entrance area). This site has been the subject of detailed multidisciplinary investigations (incorporating archaeology, conservation and heritage assessment) on questions relating to the morphology of the palaeo-entrance and the age of the cave's closure through rock collapse.

The main aim of this thesis is to propose a novel method for generalization of 3D building models with respect to topology in 3D space. The first part gives an overview over spatial data structures and methods for generalization of 3D objects. The second part presents the methodology composed of volumetric mo- del reconstruction, topology validation and simplification of geometry based on mathematical morphology approach to build multi scale model. Method is then implemented and experimental results are presented. In conclusion results are discussed and possible improvements are suggested.

Although many selection techniques have been proposed and developed over the years, selection by pointing is perhaps the most popular approach for selection. In 3D interfaces, the laser-pointer metaphor is commonly used, since users only have to point to their target from a distance. However, the task of selecting objects that have a small visible area or that are in highly cluttered environments is hard when using pointing techniques. With both indirect and direct pointing techniques in 3D interfaces, smaller targets require higher levels of pointing precision from the user. In addition, issues such as target occlusion as well as hand and tracker jitter negatively affect user performance. Therefore, requiring the user to perform selection in a single precise step may result in users spending more time to select targets so that they can be more accurate (effect known as the speed-accuracy trade-off). We describe an approach to address this issue, called Progressive Refinement. Instead of performing a single precise selection, users gradually reduce the set of selectable objects to reduce the required precision of the task. This approach, however, has an inherent trade-off when compared to immediate selection techniques. Progressive refinement requires a gradual process of selection, often using multiple steps, although each step can be fast, accurate, and nearly effortless. Immediate techniques, on the other hand, involve a single-step selection that requires effort and may be slower and more error-prone. Therefore, the goal of this work was to explore this trade-off. The research includes the design and evaluation of progressive refinement techniques for 3D interfaces, using both pointing- and gesture-based interfaces for single-object selection and volume selection. Our technique designs and other existing selection techniques that can be classified as progressive refinement were used to create a design space. We designed eight progressive refinement techniques and compared them to the most commonly used techniques (for a baseline comparison) and to other state-of-the-art selection techniques in a total of four empirical studies. Based on the results of the studies, we developed a set of design guidelines that will help other researchers design and use progressive refinement techniques. / Ph. D.

Depuis deux décennies, des chercheurs et des diffuseurs utilisent des modélisations 3D pour rendre compte d'espaces et de structures du passé. Cependant, les historiens demeurent généralement réticents envers cette manière de représenter l'histoire. Pourtant, la science historique peut tirer parti du 3D de plusieurs façons. Une modélisation peut servir de laboratoire, une approche déjà utilisée en archéologie. Par exemple, à partir d'un modèle 3D du Colisée, les historiens pourraient s'intéresser aux interactions entre la population romaine et le bâtiment, aux techniques de construction, à l'impact de cette architecture monumentale sur l'évolution urbaine. La modélisation ne doit pas non plus se limiter aux grands monuments du passé. L'évolution de l'architecture vernaculaire, d'un quartier populaire, d'un complexe industriel ou d'un village aborigène peut tout aussi bien se prêter à une analyse tirant profit d'une modélisation. Mais avant d'intégrer une telle approche à la discipline historique, il faut assurer les chercheurs du caractère scientifique d'une maquette 3D. Un tel environnement doit pouvoir répondre aux mêmes critères scientifiques que toute autre production historique de nature académique. De tels systèmes – incorporant des objets virtuels, des sources et des éléments narratifs – sont présentement en développement, et je porterai donc mon attention sur l'élaboration d'une procédure efficace pour créer des environnements virtuels pertinents respectant les pratiques historiennes.

The main scope of this work was to investigate whether it is possible to produce free standing 3D structures by the means of spraying and using MFC as raw material. This was carried out by diluting MFC into a consistency of 2% and spraying it onto a male mould. During the trials, several different devices and procedures were investigated in order to find a possible solution. The results from the laboratory trials showed that it is possible to create trays of MFC that could suitable as a detail for packaging. The important thing was to pre-heat the mould before spraying, build the tray in layers, where spraying should be carried out in a 45° angle, with single sweeps while rotating the mould in the beginning of the process, and to use a drying method, were the drying could be focused on the wet parts at the same time as it could avoid those who already had been dried, to dry the sample between each layer of MFC until the wet surface disappeared. Exactly how many sweeps per layer that should be sprayed after the first drying does not matter much, the important thing was that the layers do not become too thick. Because then, too much moisture was trapped inside the samples which made them burst during the drying.

ITC/USA 2015 Conference Proceedings / The Fifty-First Annual International Telemetering Conference and Technical Exhibition / October 26-29, 2015 / Bally's Hotel & Convention Center, Las Vegas, NV / This paper describes the details of design and critical analysis of the process of 3D printing antennas for wireless communications applications. The subjective testing methods utilized were chosen specifically based on project scope and researcher capability. Our results indicate that more work is necessary in this field but that the basic idea is feasible.

Deformation, profile and tomography measurement is critical for engineering materials characterization and engineering structure component design, analysis and biomedical application. The current existing 3D measurement method, such as stylus based profilometry, 3D optical stereo imaging and focus stacking, either suffers from low sampling speed from spatial scanning or maximum thickness of the specimen that could be imaged due to physical constraints. This thesis is dedicated to develop a hybrid 3D measurement method that can be easily implemented with fast imaging speed for dynamic process at the microscale. Also, at the microscale, the reduced depth of focus of existing microscope system greatly limits the maximum depth of the specimen that could be imaged, especially at high magnification. In this study, a 3D tomography system will be developed with extended depth of focus and improved axial resolution.