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Large planetary data visualization using ROAM 2.0Persson, Anders January 2005 (has links)
The problem of estimating an adequate level of detail for an object for a specific view is one of the important problems in computer 3d-graphics and is especially important in real-time applications. The well-known continuous level-of-detail technique, Real-time Optimally Adapting Meshes (ROAM), has been employed with success for almost 10 years but has at present, due to rapid development of graphics hardware, been found to be inadequate. Compared to many other level-of-detail techniques it cannot benefit from the higher triangle throughput available on graphics cards of today. This thesis will describe the implementation of the new version of ROAM (informally known as ROAM 2.0) for the purpose of massive planetary data visualization. It will show how the problems of the old technique can be bridged to be able to adapt to newer graphics card while still benefiting from the advantages of ROAM. The resulting implementation that is presented here is specialized on spherical objects and handles both texture and geometry data of arbitrary large sizes in an efficient way.
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Avaliação da estabilidade microestrutural do aço ferrítico-martensítico Eurofer-97 recozido isotermicamente até 1350°C / Microstructural stability of ferritic-martensitic Eurofer-97 steel annealed up to 1350oCVerona Biancardi Oliveira 30 June 2014 (has links)
A geração de novas fontes de energia limpa, segura e renovável por meio da fusão nuclear envolve importantes desafios tecnológicos, dentre eles a pesquisa, caracterização e a fabricação de materiais avançados para os futuros reatores de fusão nuclear. Os aços ferrítico-martensíticos de reduzida atividade radioativa, em especial a liga Eurofer-97, destacam-se por apresentar uma combinação única de propriedades para esta aplicação. O objetivo desta Tese de Doutorado é avaliar a estabilidade microestrutural deste aço recozido numa ampla faixa de temperaturas. Cálculos termodinâmicos e testes de dilatometria foram usados para determinar as temperaturas de transformação de fase. A estabilidade microestrutural foi estudada por meio de recozimentos isotérmicos entre 200 e 1350oC após laminação a frio com reduções de 40, 70, 80 e 90%. A avaliação da estabilidade mecânica do aço Eurofer-97 foi realizada por meio de medidas de dureza Vickers. As principais técnicas utilizadas para caracterização microestrutural foram microscopias eletrônica de varredura e de transmissão, tomografia por sonda atômica e medidas de magnetização DC. Tanto a textura como a microtextura foram determinadas por meio de medidas de difração de raios X e de elétrons retroespalhados (EBSD). Recuperação, recristalização primária e crescimento anormal de grão ocorrem neste material recozido abaixo de 800oC. Acima desta temperatura, a transformação martensítica ocorre alterando bastante a micoroestrutura. A cinética de crescimento anormal de grão é alterada pela quantidade de redução a frio previamente aplicada. A hipótese proposta para explicar o crescimento anormal de grãos neste material baseia-se principalmente na vantagem de tamanho adquirida pelos núcleos de recristalização primária com diferenças de orientação médias superiores a 45º em relação aos vizinhos. Neste caso, o crescimento anormal de grão é responsável por fortalecer as componentes {111} e {111}, {001} e {110}. Acima de 800oC a transformação martensítica prevalece elevando a dureza Vickers e randomizando a textura deste aço. As características do produto transformado dependem tanto da temperatura de austenitização quanto do tamanho incial do grão ferrítico. Os dados de composição química das partículas estáveis após recozimento em temperaturas inferiores a 800oC foram usados para validar os resultados dos cálculos termodinâmicos obtidos via Thermo-Calc. / Clean, safe, and renewable energy sources such as nuclear fusion comprise important technological challenges, including research, characterization and manufacture of advanced materials for future fusion reactors. Modified ferritic-martensitic steels with reduced radioactive activity (RAFM), especially Eurofer-97 steel, are among worldwide references in the nuclear field for their unique properties. The scope of this Thesis is to evaluate the microstructural (thermal) stability in ferritic-martensitic Eurofer-97 after annealing within a wide range of temperatures. Themodinamic calculations as well as dilatometric tests were used to determine the main phase transformation temperatures. The microstructural stability of this steel was followed by isothermal annealing between 200 and 1350°C after cold rolling to 40, 70, 80 and 90% reductions in thickness. The mechanical stability in the Eurofer-97 was assessed by Vickers microhardness measurements. Representative samples for each metallurgical condition were characterized by scanning electron microscopy, transmission electron microscopy, atom probe tomography, and DC-magnetization tests. Both texture and microtexture were evaluated by X-ray diffraction and electron backscattered diffraction (EBSD) techniques. Recovery, primary recrystallization, and abnormal grain growth (secondary recrystallization) processes have been observed at temperatures below 800°C. The amount of abnormally grown grains depends on the amount of previous cold rolling. The hypothesis for the most probable mechanism responsible for abnormal grain growth is based on the advantage size acquired by nuclei with misorientations above 45º surrounding their neighboring grains, even in regions where primary recrystallization was incomplete. The texture developed after abnormal grain growth has components belonging to ?- and ?-fibers with predominance of {111}, {111}, {100} e {110} components. The martensite transformation takes place when this steel is annealed above 800°C causing an increase of hardness, significant changes in microstructure, and texture weakening. The martensitic sructure depends very much on both austenitization temperature and initial austenitic grain size. The results of chemical analyses of stable particles present in samples annealed below 800oC were used to validate the thermodynamic calculations provided by Thermo-Calc.
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Multi color space LBP-based feature selection for texture classification / Sélection d'attributs multi-espace à partir de motifs binaires locaux pour la classification de textures couleurTruong Hoang, Vinh 15 February 2018 (has links)
L'analyse de texture a été largement étudiée dans la littérature et une grande variété de descripteurs de texture ont été proposés. Parmi ceux-ci, les motifs binaires locaux (LBP) occupent une part importante dans la plupart des applications d'imagerie couleur ou de reconnaissance de formes et sont particulièrement exploités dans les problèmes d'analyse de texture. Généralement, les images couleurs acquises sont représentées dans l'espace colorimétrique RGB. Cependant, il existe de nombreux espaces couleur pour la classification des textures, chacun ayant des propriétés spécifiques qui impactent les performances. Afin d'éviter la difficulté de choisir un espace pertinent, la stratégie multi-espace couleur permet d'utiliser simultanémentles propriétés de plusieurs espaces. Toutefois, cette stratégie conduit à augmenter le nombre d'attributs, notamment lorsqu'ils sont extraits de LBP appliqués aux images couleur. Ce travail de recherche est donc axé sur la réduction de la dimension de l'espace d'attributs générés à partir de motifs binaires locaux par des méthodes de sélection d'attributs. Dans ce cadre, nous considérons l'histogramme des LBP pour la représentation des textures couleur et proposons des approches conjointes de sélection de bins et d'histogrammes multi-espace pour la classification supervisée de textures. Les nombreuses expériences menées sur des bases de référence de texture couleur, démontrent que les approches proposées peuvent améliorer les performances en classification comparées à l'état de l'art. / Texture analysis has been extensively studied and a wide variety of description approaches have been proposed. Among them, Local Binary Pattern (LBP) takes an essential part of most of color image analysis and pattern recognition applications. Usually, devices acquire images and code them in the RBG color space. However, there are many color spaces for texture classification, each one having specific properties. In order to avoid the difficulty of choosing a relevant space, the multi color space strategy allows using the properties of several spaces simultaneously. However, this strategy leads to increase the number of features extracted from LBP applied to color images. This work is focused on the dimensionality reduction of LBP-based feature selection methods. In this framework, we consider the LBP histogram and bin selection approaches for supervised texture classification. Extensive experiments are conducted on several benchmark color texture databases. They demonstrate that the proposed approaches can improve the state-of-the-art results.
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Consolidation des poudres métalliques par des déformations plastiques extrêmes : torsion sous haute pression : expériences et modélisations / Consolidation of Metal Powders through Severe Plastic Deformation : High Pressure Torsion : Experiments and ModelingZhao, Yajun 29 February 2016 (has links)
Les procédés d’hyper-déformations (SPD) peuvent imposer de très grandes déformations à un métal et en transformer les propriétés métallurgiques de la matière en introduisant une forte densité de dislocations et un important affinement de la microstructure. Dans ce travail de thèse présenté, des expériences en torsion à haute pression (HPT) ont été réalisées pour la consolidation des différentes poudres de fer de taille à l’échelle nano et micrométrique. Ces expériences ont été effectuées avec succès à la température ambiante aboutissant à la fois à un faible niveau de porosité résiduelle et l'affinement significatif de la taille de grain, grâce à une importante déformation en cisaillement et à de la pression hydrostatique appliquée au procédé HPT. La compression a été faite en deux étapes: d'abord une compression axiale, puis déformation en cisaillement en tournant la partie inférieure de la filière HPT tout en maintenant constante la force axiale. L'homogénéité de la déformation en cisaillement à travers l'épaisseur du disque a été examinée par une mesure de déformation locale, qui montre une distribution du gradient. L'analyse par diffraction à rayons X a été réalisée sur des échantillons consolidés qui ont révélé une proportion peu importante d’oxydes. L'effet de la déformation en cisaillement sur la microstructure et la texture a été étudié par microscopie électronique à balayage et EBSD. La micro-dureté et la porosité moyenne des échantillons en fonction de la déformation en cisaillement, à pression hydrostatique constante, ont également été mesurées. Une trame de modélisation mise en œuvre dans le modèle de Taylor a été développée pour simuler l'effet du glissement aux joints de grains pour l'évolution de la texture cristallographique. Le principal effet constaté est un décalage des orientations idéales dans les conditions de cisaillement simple, ce qui a été vérifié expérimentalement. Le procédé de consolidation par HPT a été simulé numériquement en utilisant la méthode des éléments finis pour un modèle de plasticité des poudres. La simulation de ce dernier a permis de confirmer la porosité résiduelle moyenne observée expérimentalement et les différents gradients de la déformation plastique. La distribution de la densité locale a également été modélisée / Severe plastic deformation (SPD) processes can impose extremely large strains to a metal and transforming the metallurgical state of the material by introducing high dislocation density and high level of microstructure refinement. In the present thesis work High Pressure Torsion (HPT) experiments were performed for consolidation of different powders including Nano- and Micro- scaled iron powders. The experiments were carried out successfully at room temperature, achieving both low level of residual porosity and significant grain refinement, thanks to the intense shear strain and hydrostatic pressure applied in HPT. The compaction was done in two steps: first axial compaction, then shear deformation by rotating the bottom part of the HPT die while maintaining the axial force constant. The homogeneity of shear strain across the thickness of the disk was examined by local strain measurement, showing a gradient distribution. X-ray diffraction analysis was carried out on the consolidated samples which revealed no significant proportion of oxides. The effect of shear deformation on the microstructure and texture was investigated by metallographic scanning electron microscopy and electron backscattered diffraction (EBSD). The micro-hardness and average porosity of the samples as a function of shear strain at constant hydrostatic pressure were also measured. A modeling frame implemented into the Taylor model was developed to simulate the effect of Grain Boundary Sliding (GBS) on the evolution of crystallographic texture. The main effect found is a shift of the ideal orientations under simple shear conditions, which was verified experimentally. The consolidation process by HPT was simulated numerically using the finite element method together with a powder plasticity model. The simulation of the consolidation process permitted to confirm the experimentally observed average residual porosity and the different gradients in the plastic strain. The local density distribution was also modeled
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Paradigmes de segmentation de graphe : comparaisons et applications en traitement d'images / Graph segmentation paradigms : comparisons and applications in image processingAllène, Cédric 12 February 2009 (has links)
Les techniques de segmentation de graphe sont souvent utilisées en traitement d’images puisque ces dernières peuvent être vues comme des graphes valués. Dans cette thèse, nous montrons des liens existant entre plusieurs paradigmes de segmentation de graphes valués. Nous présentons tout d’abord différentes définitions de ligne de partage des eaux et sélectionnons celle dont le cadre permet la comparaison avec des forêts couvrantes particulières. Nous montrons qu’une telle ligne de partage des eaux relative à des marqueurs arbitraires est équivalente à une coupe induite par une forêt couvrante de chemins de moindre altitude. Ensuite, les coupes induites par des forêts couvrantes de poids minimum sont démontrées comme étant des cas particuliers ayant l’avantage d’éviter certaines segmentations non souhaitées. Enfin, nous montrons qu’une coupe minimale coïncide avec une coupe induite par une forêt couvrante de poids maximum pour certaines fonctions de poids particulières. Dans une seconde partie, nous présentons deux applications utilisant la segmentation de graphe : la renaissance d’images et le mélange de textures pour la reconstruction 3D / Graph segmentation techniques are often used in image processing since an image can be seen as a weighted graph. In this thesis, we show some links existing between several weighted graph segmentation paradigms. We first present different definitions of watersheds and select the one which framework allows comparison with specific spanning forests. We show that such a watershed relative to arbitrary markers is equivalent to a cut induced by a shortest path spanning forest. Then, cuts induced by minimum spanning forests are demonstrated as being particular cases which advantageously avoid some undesirable results. Finally, we show that minimum cuts coincide with cuts induced by maximum spanning forests for some particular weight functions. In a second part, we present two applications using graph segmentation : image renaissance and texture blending for 3D reconstruction
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Desempenho de cultivares de soja em latossolos vermelhos com diferentes classes texturais / Performance of soybean cultivars in different soil classesFlores, Antonio José Meireles 17 November 2010 (has links)
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Previous issue date: 2010-11-17 / Soybean is considered the main crop in Brazil due to both volume production and income. Many factors have contributed to a good performance of this crop in this country, such as adaptability of cultivars to many regions. The objective of this research was to evaluate soybean performance of early, semi-early and intermediate maturity cultivars in a sandy loam, clayey and very clayey Eutrudox. The experiment was carried out in Naviraí, Mato Grosso do Sul, Brazil, São Francisco Farm, in 2008/2009. The experimental design was the completely randomized block with four replications. The following soybean cultivars were evaluated: a) Early maturity: CD 202, CD 208 and CD 214RR; b) Semi early maturity: BRS 239, BRS CharruaRR and BRS 245RR; and c) Intermediate maturity: CD 219RR and Monsoy 8001. Sowing was conducted over maize residues on November, 15th, 2008 under no tillage system and 333 kg ha-1 of fertilizer was applied. The number of pods per plant, number of grains per pod, weight of 1,000 grains and yield (kg ha-1) were evaluated. Fertilization and maintenance of intermediate-high nutrient levels in Eutrudox soils of any textures provides conditions for soybean cultivars to express high yield potentials. / A soja é a principal cultura do País tanto em volume como em geração de renda, sendo que vários fatores tem contribuído para esse bom desempenho no Brasil, dentre eles podemos citar a adaptabilidade de cultivares ás diferentes regiões produtoras. O objetivo deste trabalho foi de avaliar o desempenho de cultivares de soja dos ciclos precoce, semiprecoce e médio em Latossolos Vermelhos com diferentes classes texturais. Latossolo Vermelho Eutrófico textura média, Latossolo Vermelho Eutrófico textura argilosa e Latossolo Vermelho Eutrófico textura muito argilosa. O experimento foi conduzido no município de Naviraí Estado de Mato Grosso do Sul, na Fazenda São Francisco, na safra agrícola 2008/2009. O delineamento experimental foi de blocos inteiramente casualisados com quatro repetições. Os cultivares de soja utilizados foram: a) Ciclo precoce: CD 202, CD 208 e CD 214RR; b) Ciclo semiprecoce: BRS 239, BRS CharruaRR, BRS 245RR e c) Ciclo médio: CD 219RR e Monsoy 8001. Em todos os solos o plantio ocorreu no dia 15 de novembro de 2008, em sistema de plantio direto sobre a resteva de milho com adubação de 333 kg ha-1. Foram avaliados os parâmetros de número de vagens por planta, número de grãos por vagens, peso de mil grãos e calculado produtividade em quilogramas por hectare. Independente da classe textural, a fertilização e manutenção de médios a altos teores de nutrientes nos LATOSSOLOS VERMELHOS Eutróficos de textura média a muito argilosa possibilita a expressão fenotípica de altas produtividades agrícolas de grãos pelas cultivares de soja.
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Desempenho de cultivares de soja em latossolos vermelhos com diferentes classes texturais / Performance of soybean cultivars in different soil classesFlores, Antonio José Meireles 17 November 2010 (has links)
Made available in DSpace on 2016-07-18T17:51:06Z (GMT). No. of bitstreams: 1
Dissertacao.pdf: 291613 bytes, checksum: 351209f8c0af1b2f460925dd83ce0a2d (MD5)
Previous issue date: 2010-11-17 / Soybean is considered the main crop in Brazil due to both volume production and income. Many factors have contributed to a good performance of this crop in this country, such as adaptability of cultivars to many regions. The objective of this research was to evaluate soybean performance of early, semi-early and intermediate maturity cultivars in a sandy loam, clayey and very clayey Eutrudox. The experiment was carried out in Naviraí, Mato Grosso do Sul, Brazil, São Francisco Farm, in 2008/2009. The experimental design was the completely randomized block with four replications. The following soybean cultivars were evaluated: a) Early maturity: CD 202, CD 208 and CD 214RR; b) Semi early maturity: BRS 239, BRS CharruaRR and BRS 245RR; and c) Intermediate maturity: CD 219RR and Monsoy 8001. Sowing was conducted over maize residues on November, 15th, 2008 under no tillage system and 333 kg ha-1 of fertilizer was applied. The number of pods per plant, number of grains per pod, weight of 1,000 grains and yield (kg ha-1) were evaluated. Fertilization and maintenance of intermediate-high nutrient levels in Eutrudox soils of any textures provides conditions for soybean cultivars to express high yield potentials. / A soja é a principal cultura do País tanto em volume como em geração de renda, sendo que vários fatores tem contribuído para esse bom desempenho no Brasil, dentre eles podemos citar a adaptabilidade de cultivares ás diferentes regiões produtoras. O objetivo deste trabalho foi de avaliar o desempenho de cultivares de soja dos ciclos precoce, semiprecoce e médio em Latossolos Vermelhos com diferentes classes texturais. Latossolo Vermelho Eutrófico textura média, Latossolo Vermelho Eutrófico textura argilosa e Latossolo Vermelho Eutrófico textura muito argilosa. O experimento foi conduzido no município de Naviraí Estado de Mato Grosso do Sul, na Fazenda São Francisco, na safra agrícola 2008/2009. O delineamento experimental foi de blocos inteiramente casualisados com quatro repetições. Os cultivares de soja utilizados foram: a) Ciclo precoce: CD 202, CD 208 e CD 214RR; b) Ciclo semiprecoce: BRS 239, BRS CharruaRR, BRS 245RR e c) Ciclo médio: CD 219RR e Monsoy 8001. Em todos os solos o plantio ocorreu no dia 15 de novembro de 2008, em sistema de plantio direto sobre a resteva de milho com adubação de 333 kg ha-1. Foram avaliados os parâmetros de número de vagens por planta, número de grãos por vagens, peso de mil grãos e calculado produtividade em quilogramas por hectare. Independente da classe textural, a fertilização e manutenção de médios a altos teores de nutrientes nos LATOSSOLOS VERMELHOS Eutróficos de textura média a muito argilosa possibilita a expressão fenotípica de altas produtividades agrícolas de grãos pelas cultivares de soja.
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Opérateurs convolutionnels dans le plan temps-fréquence / Convolutional operators in the time-frequency domainLostanlen, Vincent 02 February 2017 (has links)
Dans le cadre de la classification de sons,cette thèse construit des représentations du signal qui vérifient des propriétés d’invariance et de variabilité inter-classe. D’abord, nous étudions le scattering temps- fréquence, une représentation qui extrait des modulations spectrotemporelles à différentes échelles. Enclassification de sons urbains et environnementaux, nous obtenons de meilleurs résultats que les réseaux profonds à convolutions et les descripteurs à court terme. Ensuite, nous introduisons le scattering en spirale, une représentation qui combine des transformées en ondelettes selon le temps, selon les log-fréquences, et à travers les octaves. Le scattering en spirale suit la géométrie de la spirale de Shepard, qui fait un tour complet à chaque octave. Nous étudions les sons voisés avec un modèle source-filtre non stationnaire dans lequel la source et le filtre sont transposés au cours du temps, et montrons que le scattering en spirale sépare et linéarise ces transpositions. Le scattering en spirale améliore lesperformances de l’état de l’art en classification d’instruments de musique. Outre la classification de sons, le scattering temps-fréquence et le scattering en spirale peuvent être utilisés comme des descripteurspour la synthèse de textures audio. Contrairement au scattering temporel, le scattering temps-fréquence est capable de capturer la cohérence de motifs spectrotemporels en bioacoustique et en parole, jusqu’à une échelle d’intégration de 500 ms environ. À partir de ce cadre d’analyse-synthèse, une collaboration artscience avec le compositeur Florian Hecker / This dissertation addresses audio classification by designing signal representations which satisfy appropriate invariants while preserving inter-class variability. First, we study time-frequencyscattering, a representation which extract modulations at various scales and rates in a similar way to idealized models of spectrotemporal receptive fields in auditory neuroscience. We report state-of-the-artresults in the classification of urban and environmental sounds, thus outperforming short-term audio descriptors and deep convolutional networks. Secondly, we introduce spiral scattering, a representationwhich combines wavelet convolutions along time, along log-frequency, and across octaves. Spiral scattering follows the geometry of the Shepard pitch spiral, which makes a full turn at every octave. We study voiced sounds with a nonstationary sourcefilter model where both the source and the filter are transposed through time, and show that spiral scattering disentangles and linearizes these transpositions. Furthermore, spiral scattering reaches state-of-the-art results in musical instrument classification ofsolo recordings. Aside from audio classification, time-frequency scattering and spiral scattering can be used as summary statistics for audio texture synthesis. We find that, unlike the previously existing temporal scattering transform, time-frequency scattering is able to capture the coherence ofspectrotemporal patterns, such as those arising in bioacoustics or speech, up to anintegration scale of about 500 ms. Based on this analysis-synthesis framework, an artisticcollaboration with composer Florian Hecker has led to the creation of five computer music
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El Palacio de VersallesContreras Vargas, Paula Cristina 07 June 2021 (has links)
La presente investigación tiene como objetivo explicar el significado del Palacio de Versalles en su historia. Asimismo, explorar y analizar sus elementos arquitectónicos internos, externos y los estilos artísticos presentes en el palacio. Se realizó una investigación que permitió utilizar el proceso creativo como metodología con la finalidad de crear una colección de indumentaria. Además, se realizó una entrevista a un experto para profundizar y conocer desde otro enfoque el tema central del proyecto. Se encontró que el Palacio de Versalles está basado en una serie de cambios y adaptaciones a petición de cada monarca. Sin embargo, cada detalle del palacio está en perfecto balance y armonía. Sus propiedades más resaltantes son el orden, la jerarquía y la simetría. El monarca, que estuvo a cargo de gran parte de su edificación e implementación fue Louis XIV, también conocido como Rey Sol, quien buscaba utilizar la residencia real como un arma política para demostrar el poder y la grandeza de Francia. / The present investigation aims to explain the significance of the Palace of Versailles in its history. Also, explore and analyze its internal and external architectural elements and the artistic styles present in the palace. The investigation allows to use the creative process as a methodology to create a fashion collection. In addition, an interview to an expert was conducted to deepen and learn from another perspective the central theme of the project. It was found that the Palace of Versailles was based on a series of changes and adaptions as a request of each monarch. However, every detail of the palace is in perfect balance and harmony. The most outstanding characteristics are order, hierarchy, and symmetry. The monarch, who oversaw a big part of the construction and implementation was Louis XIV, also known as the Sun King, who seek to use the royal residence as a political weapon to show the power and greatness of France. / Trabajo de investigación
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Zobrazování rozsáhlých scén / Large Scene RenderingLanger, Lukáš January 2016 (has links)
Work discusses rendering of complex scenes and terrain. It's main task is to show the extensive scenery terrain that normally do not fit in the graphic card memory. It introduce the theory of terrain rendering including terrain level of detail algoritms. The paper presents the design and implementation of application that implements dynamic streaming of complex terrain.
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