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SANTOS, PAULO IVSON NETTO. „RAY TRACING DYNAMIC SCENES ON THE GPU“. PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2009. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=31443@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROO objetivo deste trabalho é desenvolver uma solução completa para o traçado de raios de cenas dinâmicas utilizando a GPU. Para que este algoritmo atinja desempenho interativo, é necessário utilizar uma estrutura espacial para reduzir os testes de interseção entre raios e triângulos da cena. Observa-se que, quando há movimento na cena, é necessário atualizar esta estrutura de aceleração, seja alterando-a parcialmente ou reconstruindo-a inteiramente. Adotamos a segunda estratégia por ser capaz de tratar o caso geral de movimento não-estruturado. Como a construção da estrutura deve ser feita da forma mais eficiente possível, escolhemos utilizar uma Grade Uniforme como foco de nossa pesquisa. Suas vantagens incluem um algoritmo de construção simples e um percurso de raios eficiente. Para explorar o poder de processamento em paralelo de uma GPU, é necessário manter os dados da cena e da estrutura de aceleração dentro da placa gráfica, evitando transferências custosas de memória entre a GPU e a CPU. Propomos neste trabalho uma técnica para construir uma grade uniforme inteiramente na GPU. Usando nosso método, é possível reconstruir toda a estrutura em poucos milissegundos, enquanto mantém-se a alta qualidade da grade obtida. Além disso, propomos uma implementaçoes do algoritmo de traçado de raios de forma a aproveitar o processamento em paralelo da GPU. Nosso procedimento é implementado inteiramente dentro da placa gráfica, onde há acesso direto para os dados dos triângulos da cena, bem como as informações da grade uniforme construída. Utilizando a solução proposta, somos capazes de obter taxas de visualização interativas mesmo para cenas com movimentos não-estruturados, incluindo texturas, sombras e até mesmo reflexões.
We present a technique for ray tracing dynamic scenes using the GPU. In order to achieve interactive rendering rates, it is necessary to use a spatial structure to reduce the number of ray-triangle intersections performed. Whenever there is movement in the scene, this structure is entirely rebuilt. This way, it is possible to handle general unstructured motion. For this purpose, we have developed an algorithm for reconstructing Uniform Grids entirely inside the graphics hardware. In addition, we present ray-traversal and shading algorithms fully implemented on the GPU, including textures, shadows and reections. Combining these techniques, we demonstrate interactive ray tracing performance for dynamic scenes, even with unstructured motion and advanced shading effects.
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Samothrakis, Stavros Nikolaou. „Acceleration techniques in ray tracing for dynamic scenes“. Thesis, University of Sussex, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.241671.
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Günther, Johannes Verfasser], und Philipp [Akademischer Betreuer] [Slusallek. „Ray tracing of dynamic scenes / Johannes Günther. Betreuer: Philipp Slusallek“. Saarbrücken : Saarländische Universitäts- und Landesbibliothek, 2014. http://d-nb.info/1061022463/34.
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Chang, Chen Hao Jason. „The study of energy consumption of acceleration structures for dynamic CPU and GPU ray tracing“. Worcester, Mass. : Worcester Polytechnic Institute, 2007. http://www.wpi.edu/Pubs/ETD/Available/etd-010807-140122/.
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Sjöberg, Joakim, und Filip Zachrisson. „A Performance Comparison of Dynamic- and Inline Ray Tracing in DXR : An application in soft shadows“. Thesis, Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-21833.
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Background. Ray tracing is a tool that can be used to increase the quality of the graphics in games. One application in graphics that ray tracing excels in is generating shadows because ray tracing can simulate how shadows are generated in real life more accurately than rasterization techniques can. With the release of GPUs with hardware support for ray tracing, it can now be used in real-time graphics applications to some extent. However, it is still a computationally heavy task requiring performance improvements. Objectives. This thesis will evaluate the difference in performance of three raytracing methods in DXR Tier 1.1, namely dynamic ray tracing and two forms of inline ray tracing. To further investigate the ray-tracing performance, soft shadows will be implemented to see if the driver can perform optimizations differently (depending on the choice of ray-tracing method) on the subsequent and/or preceding API interactions. With the pipelines implemented, benchmarks will be performed using different GPUs, scenes, and a varying amount of shadow-casting lights. Methods. The scientific method is based on an experimental approach, using both implementation and performance tests. The experimental approach will begin by extending an in-house DirectX 12 renderer. The extension includes ray-tracing functionality, so that hard shadows can be generated using both dynamic- and the inline forms ray tracing. Afterwards, soft shadows are generated by implementing a state-of-the-art-denoiser with some modifications, which will be added to each ray-tracing method. Finally, the renderer is used to perform benchmarks of various scenes with varying amounts of shadow-casting lights and object complexity to cover a broad area of scenarios that could occur in a game and/or in other similar applications. Results and Conclusions. The results gathered in this experiment suggest that under the experimental conditions of the chosen scenes, objects, and number of lights, AMD’s GPUs were faster in performance when using dynamic ray tracing than using inline ray tracing, whilst Nvidia’s GPUs were faster when using inline ray tracing compared to when using dynamic ray tracing. Also, with an increasing amount of shadow-casting lights, the choice of ray-tracing method had low to no impact except for linearly increasing the execution time in each test. Finally, adding soft shadows(subsequent and preceding API interactions) also had low to no relative impact on the results depending on the different ray-tracing methods.Bakgrund. Strålspårning (ray tracing) är ett verktyg som kan användas för att öka kvalitén på grafiken i spel. En tillämpning i grafik som strålspårning utmärker sig i är när skuggor ska skapas eftersom att strålspårning lättare kan simulera hur skuggor skapas i verkligheten, vilket tidigare tekniker i rasterisering inte hade möjlighet för. Med ny hårdvara där det finns support för strålspårning inbyggt i grafikkorten finns det nu möjligheter att använda strålspårning i realtids-applikationer inom vissa gränser. Det är fortfarande tunga beräkningar som behöver slutföras och det är därav att det finns behov av förbättringar. Syfte. Denna uppsats kommer att utvärdera skillnaderna i prestanda mellan tre olika strålspårningsmetoder i DXR nivå 1.1, nämligen dynamisk strålspårning och två olika former av inline strålspårning. För att ge en bredare utredning på prestandan mellan strålspårningsmetoderna kommer mjuka skuggor att implementeras för att se om drivrutinen kan göra olika optimiseringar (beroende på valet av strålspårningsmetod) på de efterföljande och/eller föregående API anropen. Efter att dessa rörledningar (pipelines) är implementerade kommer prestandatester att utföras med olika grafikkort, scener, och antal ljus som kastar skuggor. Metod. Den vetenskapliga metoden är baserat på ett experimentellt tillvägagångssätt, som kommer innehålla både ett experiment och ett flertal prestandatester. Det experimentella tillvägagångssättet kommer att börja med att utöka en egenskapad DirectX 12 renderare. Utökningen kommer tillföra ny funktionalitet för att kunna hantera strålspårning så att hårda skuggor ska kunna genereras med både dynamisk och de olika formerna av inline strålspårning. Efter det kommer mjuka skuggor att skapas genom att implementera en väletablerad avbrusningsteknik med några modifikationer, vilket kommer att bli tillagt på varje strålspårningssteg. Till slut kommer olika prestandatester att mätas med olika grafikkort, olika antal ljus, och olika scener för att täcka olika scenarion som skulle kunna uppstå i ett spel och/eller i andra liknande applikationer. Resultat och Slutsatser. De resultat från testerna i detta experiment påvisar att under dessa förutsättningar så är AMD’s grafikkort snabbare på dynamisk strålspårning än på inline strålspårning, samtidigt som Nvidias grafikkort är snabbare på inline strålspårning än på den dynamiska varianten. Ökandet av ljus som kastar skuggor påvisade låg till ingen förändring förutom ett linjärt ökande av exekveringstiden i de flesta testerna. Slutligen så visade det sig även att tillägget av mjuka skuggor (efterföljande och föregående API interaktioner) hade låg till ingen påverkan på valet av strålspårningsmetod.
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Minkara, Rania. „Locating wireless base stations within a dynamic indoor environment“. Thesis, University of Bath, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.681053.
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The mobility that wireless communication offers to users, added to the ease of installation have increased the demand on such communication systems. However, the main drawback of wireless communication is the degradation of the signal as it travels through the channel due to the different propagation mechanisms the signal undergoes. To minimise the effect of the channel and get the best service, the base stations must be appropriately located within the environment. This requires proper knowledge of the channel characteristics. Ray tracing software is used throughout this work to generate the channel characteristics of an indoor environment. After getting the channel characteristics, a novel cost function is defined based on the path loss values and it is then optimised. Once the optimal base stations’ positions are found, the minimal amount of power required to cover a predefined percentage of the possible receivers’ locations is calculated. On the other hand, a receiver’s position acquiring enough field strength does not necessarily enjoy the service. This depends on the time dispersion parameters values relative to the symbol rate. The time dispersion parameters have always been ignored in the literature while finding the optimal base stations’ locations. Three cost functions that take into consideration both the path loss and rms delay spread, for the first time in the literature, are therefore defined. The cost functions are optimised and their corresponding results are compared. Furthermore, indoor environments have always been considered static which is never realistic. They are subject to continuous changes such as opening doors and windows as well as the presence of people. The first detailed analysis and quantified results of the effect of a dynamic environment on the optimal base stations’ positions and minimal emitted power are presented. It is shown that the optimal base stations’ locations and minimal emitted power are sensitive to such environment changes. The environment changes can also disturb the service for active receivers. Three techniques to overcome the effect of environment changes and bring the disturbed service back to receivers are proposed. The first two techniques rely on increasing the emitted power or changing the antenna polarisation. The third technique is a novel technique that gives the base station the ability to automatically move in various directions within a limited distance. The techniques are tested and their efficiency and limitations are discussed.
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Frid, Kastrati Mattias. „Hybrid Ray-Traced Reflections in Real-Time : in OpenGL 4.3“. Thesis, Blekinge Tekniska Högskola, Institutionen för kreativa teknologier, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-10427.
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Context. Reaching photo realistic results when rendering 3D graphics in real-time is a hard computational task. Ray-tracing gives results close to this but is too expensive to be run at real-time frame rates. On the other hand rasterized methods such as deferred rendering are able to keep the tight time constraints with the support of modern hardware. Objectives. The basic objective is to merge deferred rendering and ray-tracing into one rasterized pipeline for dynamic scenes. In the thesis the proposed method is explained and compared to the methods it merges. Image quality, execution time and VRAM usage impact are investigated. Methods. The proposed method uses deferred rendering to render the result of the primary rays. Some pixels are marked, based on material properties for further rendering with ray-tracing. Only reflections are presented in the thesis but it has been proven that other global illumination effects can be implemented in the ray-tracing framework used. Results and Conclusions. The hybrid method is proved through experiments to be between 2.49 to 4.19 times faster than pure ray-tracing in the proposed pipeline. For smaller scenes it can be run at frame rates close to real-time, but, for larger scenes such as the Crytek Sponza scene the real-time feeling is lost. However, interactivity is never lost. It is also proved that a simple adjustment to the original framework can save almost 2/3 of the memory spent on A-buffers. Image comparisons prove that the technique can compete with offline ray tracers in terms of image quality.
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Heidari, Mohammad. „Identification and modeling of the dynamic behavior of the direct path component in ToA-based indoor localization systems“. Worcester, Mass. : Worcester Polytechnic Institute, 2008. http://www.wpi.edu/Pubs/ETD/Available/etd-071508-195549/.
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Dissertation (Ph.D.)--Worcester Polytechnic Institute.Keywords: Ray Tracing; Wideband Measurement; Dynamic Modeling of Ranging Error; ToA-Based Indoor Localization; NLoS Identification. Includes bibliographical references (leaves 147-159).
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Loyet, Raphaël. „Dynamic sound rendering of complex environments“. Phd thesis, Université Claude Bernard - Lyon I, 2012. http://tel.archives-ouvertes.fr/tel-00995328.
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De nombreuses études ont été menées lors des vingt dernières années dans le domaine de l'auralisation.Elles consistent à rendre audible les résultats d'une simulation acoustique. Ces études se sont majoritairementfocalisées sur les algorithmes de propagation et la restitution du champ acoustique dans desenvironnements complexes. Actuellement, de nombreux travaux portent sur le rendu sonore en tempsréel.Cette thèse aborde la problématique du rendu sonore dynamique d'environnements complexes selonquatre axes : la propagation des ondes sonores, le traitement du signal, la perception spatiale du son etl'optimisation informatique. Dans le domaine de la propagation, une méthode permettant d'analyser lavariété des algorithmes présents dans la bibliographie est proposée. A partir de cette méthode d'analyse,deux algorithmes dédiés à la restitution en temps réel des champs spéculaires et diffus ont été extraits.Dans le domaine du traitement du signal, la restitution est réalisée à l'aide d'un algorithme optimisé despatialisation binaurale pour les chemins spéculaires les plus significatifs et un algorithme de convolutionsur carte graphique pour la restitution du champ diffus. Les chemins les plus significatifs sont extraitsgrace à un modèle perceptif basé sur le masquage temporel et spatial des contributions spéculaires.Finalement, l'implémentation de ces algorithmes sur des architectures parallèles récentes en prenant encompte les nouvelles architectures multi-coeurs et les nouvelles cartes graphiques est présenté.
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Turk, Jeffrey A. „Acceleration techniques for the radiative analysis of general computational fluid dynamics solutions using reverse Monte-Carlo ray tracing“. Diss., This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-09192008-063033/.
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Moghimi, Ardekani Mohammad. „Optical thermal and economic optimisation of a linear Fresnel collector“. Thesis, University of Pretoria, 2017. http://hdl.handle.net/2263/61313.
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Solar energy is one of a very few low-carbon energy technologies with the enormous potential to grow to a large scale. Currently, solar power is generated via the photovoltaic (PV) and concentrating solar power (CSP) technologies. The ability of CSPs to scale up renewable energy at the utility level, as well as to store energy for electrical power generation even under circumstances when the sun is not available (after sunset or on a cloudy day), makes this technology an attractive option for sustainable clean energy. The levelised electricity cost (LEC) of CSP with thermal storage was about 0.16-0.196 Euro/kWh in 2013 (Kost et al., 2013). However, lowering LEC and harvesting more solar energy from CSPs in future motivate researchers to work harder towards the optimisation of such plants. The situation tempts people and governments to invest more in this ultimate clean source of energy while shifting the energy consumption statistics of their societies from fossil fuels to solar energy.
Usually, researchers just concentrate on the optimisation of technical aspects of CSP plants (thermal and/or optical optimisation). However, the technical optimisation of a plant while disregarding economic goals cannot produce a fruitful design and in some cases may lead to an increase in the expenses of the plant, which could result in an increase in the generated electrical power price.
The study focused on a comprehensive optimisation of one of the main CSP technology types, the linear Fresnel collector (LFC). In the study, the entire LFC solar domain was considered in an optimisation process to maximise the harvested solar heat flux throughout an imaginary summer day (optical goal), and to minimise cavity receiver heat losses (thermal goal) as well as minimising the manufacturing cost of the plant (economic goal). To illustrate the optimisation process, an LFC was considered with 12 design parameters influencing three objectives, and a unique combination of the parameters was found, which optimised the performance. In this regard, different engineering tools and approaches were introduced in the study, e.g., for the calculation of thermal goals, Computational Fluid Dynamics (CFD) and view area approaches were suggested, and for tackling optical goals, CFD and Monte-Carlo based ray-tracing approaches were introduced. The applicability of the introduced methods for the optimisation process was discussed through case study simulations. The study showed that for the intensive optimisation process of an LFC plant, using the Monte Carlo-based ray-tracing as high fidelity approach for the optical optimisation objective, and view area as a low fidelity approach for the thermal optimisation objective, made more sense due to the saving in computational cost without sacrificing accuracy, in comparison with other combinations of the suggested approaches.
The study approaches can be developed for the optimisation of other CSP technologies after some modification and manipulation. The techniques provide alternative options for future researchers to choose the best approach in tackling the optimisation of a CSP plant regarding the nature of optimisation, computational cost and accuracy of the process.Thesis (PhD)--University of Pretoria, 2017.
Mechanical and Aeronautical Engineering
PhD
Unrestricted
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Ono, Tomohiro. „Development of new irradiation techniques using gimbaled x-ray head“. Kyoto University, 2016. http://hdl.handle.net/2433/215379.
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Rink, Jochen C. „Rab-domain dynamics in endocytic membrane trafficking“. Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2005. http://nbn-resolving.de/urn:nbn:de:swb:14-1117095871452-66763.
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Eukaryotic cells depend on cargo uptake into the endocytic membrane system, which comprises a functionally interconnected network of endosomal compartments. The establishment and maintenance of such diverse compartments in face of the high rates of exchange between them, poses a major challenge for obtaining a molecular understanding of the endocytic system. Rab-GTPases have emerged as architectural key element thereof: Individual family members localize selectively to endosomal compartments, where they recruit a multitude of cytoplasmic effector proteins and coordinate them into membrane sub-domains. Such "Rab-domains" constitute modules of molecular membrane identity, which pattern the endocytic membrane system into a mosaic of Rab-domains. The main objective of this thesis research was to link such "static" mosaic-view with the highly dynamic nature of the endosomal system. The following questions were addressed: How are neighbouring Rab-domains coordinated? Are Rab-domains stable or can they undergo assembly and disassembly? Are the dynamics of Rab-domains utilized in cargo transport? The first part of this thesis research focused on the organization of Rab-domains in the recycling pathway. Utilizing Total Internal Reflection (TIRF) microscopy, Rab11-, but neither Rab4- nor Rab5-positive vesicles were observed to fuse with the plasma membrane. Rab4-positive membranes, however, could be induced to fuse in presence of Brefeldin A. Thus, these experiments complete the view of the recycling pathway by the following steps: a) Rab11-carriers likely mediate the return of recycling cargo to the surface; b) such carriers are presumably generated in an Arf-dependent fission reaction from Rab4-positive compartments. Rab11-chromatography was subsequently carried out in the hope of identifying Rab11-effectors functioning at the Rab4-Rab11 domain interface. An as yet uncharacterized ubiquitin ligase was identified, which selectively interacts with both Rab4 and Rab11. Contrary to expectations, however, the protein (termed RUL for *R*ab interacting *U*biquitin *L*igase) does not function in recycling,but appears to mediate trafficking between Golgi/TGN and endosomes instead.In order to address the dynamics of Rab-domains, fluorescently tagged Rab-GTPases were imaged during cargo transport reactions in living cells. Herefore high-speed/long-term imaging procedures and novel computational image analysis tools were developed. The application of such methodology to the analysis of Rab5-positive early endosomes showed that a) The amount of Rab5 associated with individual endosomes fluctuates strongly over time; b) such fluctuations can lead to the "catastrophic" loss of the Rab5-machinery from membranes; c) Rab5 catastrophe is part of a functional cycle of early endosomes, involving net centripetal motility, continuous growth and increase in Rab5 density. Next, the relevance of Rab5 catastrophe with respect to cargo transfer into either the recycling- or degradative pathway was examined. Recycling cargo (transferrin) could be observed to exit Rab5-positive early endosomes via the frequent budding of tubular exit carriers. Exit of degradative cargo (LDL) from Rab5-positive endosomes did not involve budding, but the rapid loss of Rab5 from the limiting membrane.Rab5-loss was further coordinated with the concomitant acquisition of Rab7, suggesting "Rab conversion" as mechanism of transport between early- and late endosomes.Altogether, this thesis research has shown that first, Rab-machineries can be acquired and lost from membranes. Second, such dynamics provide a molecular mechanism for cargo exchange between endosomal compartments. Jointly, these findings lead to the concept of Rab-domain dynamics modulation in /trans/ between neighbouring domains as mechanistic principle behind the dynamic organization of membrane trafficking pathways.
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Slootweg, Marcel. „Numerical performance analysis of novel solar tower receiver“. Diss., University of Pretoria, 2019. http://hdl.handle.net/2263/70354.
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Concern over the altering climate due to the release of anthropogenic greenhouse gases has caused a major shift in the developments of ways to minimise human impact on the climate. Solar energy is seen as one of the most promising sources to transform the energy market for low-carbon energy generation. Currently, solar power is generated via photovoltaic (PV) and concentrating solar power (CSP) technologies. The advantage of CSPs to scale up renewable energy to utility level, as well as to store thermal energy for electrical power generation when the sun is not available (after sunset or during cloudy periods) makes this technology an attractive option for sustainable clean energy. CSP development, however, is still in its infancy, and for it to be a competitive form of energy-generation technology, techno-economic developments in this field need to improve the efficiency and decrease the costs of this technology. A policy report by the European Academies’ Science Advisory Council (EASAC) (2011) indicated that central receiver (solar tower) CSP systems show the greatest margin for technological improvements (40% to 65% is estimated), and that an improvement in receiver technology could make the greatest contribution to increase efficiency.
This study therefore focused on analysing the optical and thermal performance of a new proposed solar cavity molten salt receiver design for a central receiver CSP system using a numerical approach. In this study, the receiver’s performance was analysed by first selecting an existing heliostat field, Planta Solar 10 (PS-10). For the numerical analysis to reflect conditions that are as realistic as possible, numerical models for different aspects were selected and validated. For modelling the sun, the solar tracking numerical model proposed by Iqbal (1983) was selected and implemented after literature and comparison showed adequate results. The direct normal irradiation (DNI) was modelled by applying a clear sky model, with the parameterisation model C proposed by Iqbal (1983) as the chosen model. The variables in this model that were subject to temperature, and humidity values were more accurately presented by adding numerical approximations of the region’s actual weather data. The DNI model reflected realistic fluctuations. For the thermal modelling, a validation study was conducted on impingement flow heat transfer to select an appropriate Reynolds-averaged Navier-Stokes (RANS) model that would provide accurate results when conducting the thermal performance test on the receiver. The study concluded that the transitional Shear Stress Transport (SST) turbulence model performed the best.
A new method was also developed and validated that allows one to not only simulate complex geometries within the Monte Carlo ray tracing environment SolTrace, but also to apply the results obtained by simulating this model as a heat source within the computational fluid dynamics (CFD) environment ANSYS Fluent. This allows SolTrace modelling to be more accurate, since models do not need to be approximated to simple geometries. It also provides an alternative for solar modelling in ANSYS Fluent.
The optical analysis was conducted by first performing an analysis on the receiver aperture and studying its sensitivity on the captured flux. This was followed by analysing the optics of the proposed receiver, the flux distributions on a simplified absorber surface area, and how these distributions are altered by changing some parameters. An in-depth analysis was finally done on the absorber area by applying the aforementioned model to simulate complex geometries within SolTrace, with the results illustrating the difference of the detailed geometry on optical modelling. An alternative receiver design with improved optical features was proposed, with an initial study providing promising results. The thermal analysis was done within the CFD environment, with only a section of the absorber surface area considered, and by applying the solar flux simulated during the optical analysis as heat source within the geometry model. This allowed the model to simulate the effects of re-radiation at the surface of the absorber while simulating the heat transfer at the fluid molten salt side simultaneously. The results showed that, for the current design and requirements, the absorber surface temperature reaches impractical temperatures. Altering the design or being more lenient on the requirements has, however, shown dramatic improvements in terms of thermal performance. Sensitivity studies for both the optical and thermal analyses have shown that changes in design can dramatically improve the performance of the design, making it a possible feasible receiver design for central receiver systems.Dissertation (MEng)--University of Pretoria, 2019.
National Research Foundation (NRF)
Mechanical and Aeronautical Engineering
MEng
Unrestricted
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Breuillard, Hugo. „Détermination des distributions d’ondes de type choeur dans la magnétosphère interne de la Terre et leurs conséquences sur la dynamique de la ceinture de radiation externe“. Thesis, Orléans, 2012. http://www.theses.fr/2012ORLE2081/document.
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Les ondes de type choeur sont parmi les ondes électromagnétiques les plus intenses observées dans la magnétosphère interne de la Terre, et jouent un rôle crucial dans la dynamique des ceintures de radiation terrestres qui est un enjeu majeur de la météorologie de l’espace. Elles sont en effet responsables de l’accélération et la perte des électrons énergétiques qui peuplent notamment la ceinture externe. Or, les satellites ne peuvent couvrir entièrement la magnétosphère interne, et les données de ces ondes sont pauvres dans certaines régions. Le but de cette thèse est donc de pouvoir compléter les données satellites par le biais des simulations numériques, en déterminant les distributions statistiques des ondes de type choeur dans la magnétosphère interne. Pour cela, un code dit de traçage de rayons a été développé, incluant un modèle réaliste de magnétosphère interne. La propagation des ondes choeur par le biais de ce code est d’abord décrite dans ce travail, mettant notamment l’accent sur l’importance de l’angle azimutal des ondes. Puis, en utilisant la base de données de trajectoires réalisée pour des paramètres typiques des choeurs sources, la reconstruction des distributions statistiques mesurées par Cluster est présentée. Il est ainsi démontré l’invalidité, aux moyennes et hautes latitudes, de l’approximation quasi-longitudinale utilisée dans de nombreux calculs de la dynamique des ceintures de radiation. En se basant sur ces distributions réalistes d’angles normaux, mais aussi d’amplitude des ondes, il est ensuite démontré l’importante différence obtenue sur les pertes d’électrons énergétiques. Par la suite, la précision de nos simulations numériques pour l’étude des ondes choeurs réfléchies dans la magnétosphère est mise en évidence, ainsi que leur importance étant donné le peu d’observations. Nos simulations indiquent notamment que les tons descendants d’ondes choeur peuvent provenir de la réflexion magnétosphérique de tons montantsChorus type whistler waves are one of the most intense electromagnetic waves observed in the Earth’s inner magnetosphere, and play a crucial role in the dynamics of radiation belts which is a critical issue in space weather. They are indeed responsible for acceleration and loss of the energetic electron population that shape the outer belt. As spacecraft trajectories cannot entirely cover the inner magnetosphere, satellite measurements are poor in some regions. The aim of this thesis is thus to be able to complete observational data making use of numerical simulations, by determining the statistical distributions of chorus waves in the inner magnetosphere. In order to achieve this aim, a ray tracing code has been developed, including a realistic model of the inner magnetosphere. First, wave propagation by means of this program is described in this work, emphasizing notably the significance of wave azimuthal angle. Then, making use of the trajectory database computed for typical source chorus parameters, the reconstruction of statistical distributions recorded on Cluster spacecraft is presented. It is thereby demonstrated that quasi-longitudinal approximation, used in numerous simulations of radiation belts dynamics, is no longer valid at medium and high latitudes. Taking these realistic distributions as a basis, it is then demonstrated the major discrepancy obtained for energetic electrons losses. Subsequently, the accuracy of our numerical simulations for the study of magnetospherically reflected chorus waves is highlighted, as well as their importance due to the lack of observational data. Our simulations notably indicate that falling tone chorus emissions can originate from the magnetospheric reflection of rising tone elements
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Griffin, Daniel Joe. „The extension of a non-hydrostatic dynamical core into the thermosphere“. Thesis, University of Exeter, 2018. http://hdl.handle.net/10871/34335.
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The non-hydrostatic dynamical core ENDGame (Even Newer Dynamics for the General Atmospheric Modelling of the Environment) is extended into the thermosphere to test its feasability as a whole-atmosphere dynamical core that can simulate the large scale fluid dynamics of the whole atmosphere from the surface to the top of the thermosphere at 600km. This research may have applications in the development of a Sun-to-Earth modelling system involving the Met Office Unified Model, which will be useful for space weather forecasting and chemical climate modelling. Initial attempts to raise the top boundary of ENDGame above ∼100km give rise to instabilities. To explore the potential causes of these instabilities, a one dimensional column version of ENDGame: ENDGame1D, is developed to study the effects of vertically propagating acoustic waves in the dynamical core. A 2D ray-tracing scheme is also developed, which accounts for the numerical effects on wave propagation. It is found that ENDGame’s numerics have a tendency towards the excessive focussing of wave energy towards vertical propagation, and have poor handling of large amplitude waves, also being unable to handle shocks. A key finding is that the physical processes of vertical molecular viscosity and diffusion prevent the excessive growth of wave amplitudes in the thermosphere in ENDGame, which may be crucial to improving ENDGame’s stability as it is extended upwards. Therefore, a fully implicit-in-time implementation of vertical molecular viscosity and diffusion is developed in both ENDGame1D and the full three-dimensional version of ENDGame: ENDGame3D. A new scheme is developed to deal with the viscous and diffusive terms with the dynamics terms in a fully coupled way to avoid time-splitting errors that may arise. The combination of a small amount of off-centring of ENDGame’s semi-implicit formulation and the inclusion of vertical molecular viscosity and diffusion act to make ENDGame significantly more stable, as long as the simulation is able to remain stable up to the molecularly diffused region above an altitude of ∼130km.
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Temperley, Neil Colin Mechanical & Manufacturing Engineering Faculty of Engineering UNSW. „Optimisation of an Ultrasonic Flow Meter Based on Experimental and Numerical Investigation of Flow and Ultrasound Propagation“. Awarded by:University of New South Wales. School of Mechanical and Manufacturing Engineering, 2002. http://handle.unsw.edu.au/1959.4/22044.
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This thesis presents a procedure to optimise the shape of a coaxial transducer ultrasonic flow meter. The technique uses separate numerical simulations of the fluid flow and the ultrasound propagation within a meter duct. A new flow meter geometry has been developed, having a significantly improved (smooth and monotonic) calibration curve. In this work the complex fluid flow field and its influence on the propagation of ultrasound in a cylindrical flow meter duct is investigated. A geometric acoustics (ray tracing) propagation model is applied to a flow field calculated by a commercial Computational Fluid Dynamics (CFD) package. The simulation results are compared to measured calibration curves for a variety of meter geometries having varying lengths and duct diameters. The modelling shows reasonable agreement to the calibration characteristics for several meter geometries over a Reynolds number range of 100...100000 (based on bulk velocity and meter duct diameter). Various CFD simulations are validated against flow visualisation measurements, Laser Doppler Velocimetry measurements or published results. The thesis includes software to calculate the acoustic ray propagation and also to calculate the optimal shape for the annular gap around the transducer housings in order to achieve desired flow acceleration. A dimensionless number is proposed to characterise the mean deflection of an acoustic beam due to interaction with a fluid flow profile (or acoustic velocity gradient). For flow in a cylindrical duct, the 'acoustic beam deflection number' is defined as M g* (L/D)^2, where: M is the Mach Number of the bulk velocity; g* is the average non-dimensionalised velocity gradient insonified by the acoustic beam (g* is a function of transducer diameter - typically g* = 0.5...4.5); L is the transducer separation; and D is the duct diameter. Large values of this number indicate considerable beam deflection that may lead to undesirable wall reflections and diffraction effects. For a single path coaxial transducer ultrasonic flow meter, there are practical limits to the length of a flow meter and to the maximum size of a transducer for a given duct diameter. The 'acoustic beam deflection number' characterises the effect of these parameters.
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Zubal, Miloš. „Realistická animace kouře“. Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2007. http://www.nusl.cz/ntk/nusl-412803.
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This work makes basic analysis of historical and current algorithms for smoke animation. Modern approaches to rendering volumetric data are briefly described. We choose algorithms for implementation on basis of this analysis. These algorithms are described in detail and we make emphasis on their important properties according to dedication of this work. Detailed description of implementation follows along with performance measurement. Conclusion evaluates results of work and proposes possible extensions.
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Andrienko, Daniil. „Non-equilibrium Models for High Temperature Gas Flows“. Wright State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=wright1405505300.
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Pujol, Nadal Ramon. „Comportamiento Óptico y Térmico de un Concentrador Solar Lineal con reflector estacionario y Foco Móvil“. Doctoral thesis, Universitat de les Illes Balears, 2012. http://hdl.handle.net/10803/84115.
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El concentrador solar Fixed Mirror Solar Concentrator (FMSC) apareció en los años 70 con la finalidad de reducir costes en la producción de energía termoeléctrica. Este diseño consiste en un concentrador de reflector estacionario y foco móvil, presenta buena integrabilidad en cubiertas, y es capaz de alcanzar temperaturas entre 100 y 200ºC manteniendo una eficiencia aceptable.
En esta tesis se expone una metodología para determinar el comportamiento del FMSC. Se ha desarrollado una herramienta de cálculo basada en el método de ray-tracing, que simula el trazado de los rayos solares en el sistema óptico. Con esta herramienta se ha analizado el comportamiento óptico y térmico del FMSC, y de la versión con espejos curvos Curved Slats Fixed Mirror Solar Concentrator (CSFMSC). Se ha realizado un análisis paramétrico para conocer la influencia de los distintos parámetros en el modificador de ángulo (IAM), y para obtener los diseños óptimos a una temperatura de 200ºC para tres climas en diferentes latitudes.
Se han comparado los valores teóricos obtenidos mediante ray-tracing con dos prototipos ensayados, obteniendo un buen ajuste en ambos casos. Los ensayos han sido utilizados para determinar la curva de rendimiento de uno de los prototipos. Se ha hecho uso del método propuesto en la norma EN-12975-2:2006, combinado con valores de IAM obtenidos mediante ray-tracing. Se prueba que esta combinación puede ser útil para obtener la curva de rendimiento de colectores complejos con un modelo biaxial para el IAM.The Fixed Mirror Solar Concentrator (FMSC) appeared during the 70s with the aim of reducing costs in the production of electricity in solar thermal power plants. This design consists of a concentrator with fixed reflector and moving receiver, has a very good integrability into building roofs and can reach temperatures between 100 and 200ºC with an acceptable efficiency. In this Thesis a methodology is presented for the determination of the behaviour of the FMSC. A simulation tool based on the forward ray-tracing method has been developed. The optical and thermal behaviour of the FMSC and its curved mirror variation called the Curved Slats Fixed Mirror Solar Concentrator (CSFMSC), have been analyzed with this tool. A parametric analysis has been carried out in order to determine the influence of the different parameters on the Incidence Angle Modifier (IAM) and to determine the optimal designs at a temperature of 200ºC for three different climates at different latitudes. The theoretical values obtained from the ray-tracing code have been compared with two experimental prototypes. The experimental and numerical results obtained show a good fit. The efficiency curve of one of the prototypes has been determined from the experimental tests. The methodology proposed in the norm EN-12975-2:2006 has been used in combination with IAM values obtained by ray-tracing. It has been shown that this combination can be effectively used to obtain the efficiency curve of complex collectors with a bi-axial IAM model.
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Dutheil, Yann. „Modélisation de la dynamique de spin dans l'AGS basée sur une méthode de résolution pas-à-pas du mouvement“. Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GRENY013/document.
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L'AGS fournit un faisceau de proton polarisé à RHIC. Le faisceau est accéléré dans l'AGS de Gγ = 4.5 à Gγ = 45.5 et la transmission de la polarisation est critique pour le programme de spin de RHIC. Au cours des dernières années, divers systèmes ont été mis en œuvre pour améliorer la transmission de la polarisation dans l'AGS. Ces améliorations consistent essentiellement en l'introduction de deux serpents Siberien partiels et du system de saut de nombre d'onde. Cependant, la transmission de la polarisation n'atteint pas encore 100 % durant le cycle d'accélération de l'AGS. L'efficacité actelle de la transmission de la polarisation est estimée à environ 85 % dans les conditions de fonctionnement typiques. Comprendre les sources de dépolarisation dans l'AGS est essentiel pour améliorer les performances en protons polarisés de la machine. La dynamique complexe de faisceau et de spin, notamment en présence des aimaint spécialisés appelé serpent Sibériens, justifient le fort intérÃa t pour des méthodes de simulation originales. Le code Zgoubi, capable de résoudre l'équation du mouvement et de l'évolution du spin directement à partir d'une carte de champs, est utilisé pour modéliser l'AGS. Un modèle de l'AGS utilisant le code Zgoubi a pout cette reaison été développé et interfacé avec le système actuel par une simple commande: l'AgsFromSnapRampCmd. L'interfa ̧age avec le système de contrôle de la machine permet la modélisation rapide en utilisant les paramètres de réels la machine. Ces développements ont permis de reproduire fidèlement l'optique de l'AGS le long du cycle d'accéleration. Des développements supplémentaires sur le code Zgoubi, ainsi que sur des outils de post-traitement et de pré-traitement, ont fourni au code la possibilité de suivre les faisceaux sur de nombreux tours, ce qui s'avère être fondamental pour une représentation realiste du cycle d'accélération complet de la machine. Des simulations de faisceaux sur de nombreux tours dans l'AGS, en utilisant des conditions réalistes de faisceau et de machine, ont fourni une unique vision des les mécanismes sous-jacents de l'évolution de l'émittance et de la polarisation du faisceau au cours du cycle d'accélération. Des programmes de post-traitement ont été développés pour permettre la représentation des quantités pertinentes des données simulées par Zgoubi.Les simulations se sont avérées particulièrement utiles pour mieux comprendre les pertes de polarisation à travers résonances horizontales intrinsèques de spin. Le modèle Zgoubi ainsi que les outils développés ont également été utilisées pour certaines applications directes. Par exemple, les simulations d'expériences de faisceau ont permis l'estimation précise des gains de polarisation attendus en fonction des changements apportés. En particulier, des simulations d'expériences impliquant le système de saut des nombres d'onde ont fournis des estimations précises de la polarisation gagné et permis le choix des conditions optimales de la machineThe AGS provides a polarized proton beam to RHIC. The beam is accelerated in the AGS from Gγ = 4.5 to Gγ = 45.5 and the polarization transmission is critical to the RHIC spin program. In the recent years, various systems were implemented to improve the AGS polarization transmission. These upgrades include the double partial snakes configuration and the tune jumps system. However, 100 % polarization transmission through the AGS acceleration cycle is not yet reached. The current efficiency of the polarization transmission is estimated to be around 85 % in typical running conditions. Understanding the sources of depolarization in the AGS is critical to improve the AGS polarized proton performances. The complexity of beam and spin dynamics, which is in part due to the specialized Siberian snake magnets, drove a strong interest for original methods of simulations. For that, the Zgoubi code, capable of direct particle and spin tracking through field maps, was here used to model the AGS. A model of the AGS using the Zgoubi code was developed and interfaced with the current system through a simple command: the AgsFromSnapRampCmd. Interfacing with the machine control system allows for fast modelization using actual machine parameters. Those developments allowed the model to realistically reproduce the optics of the AGS along the acceleration ramp. Additional developments on the Zgoubi code, as well as on post-processing and pre-processing tools, granted long term multiturn beam tracking capabilities: the tracking of realistic beams along the complete AGS acceleration cycle. Beam multiturn tracking simulations in the AGS, using realistic beam and machine parameters, provided a unique insight into the mechanisms behind the evolution of the beam emittance and polarization during the acceleration cycle. Post-processing softwares were developed to allow the representation of the relevant quantities from the Zgoubi simulations data. The Zgoubi simulations proved particularly useful to better understand the polarization losses through horizontal intrinsic spin resonances The Zgoubi model as well as the tools developed were also used for some direct applications. For instance, some beam experiment simulations allowed an accurate estimation of the expected polarization gains from machine changes. In particular, the simulations that involved involved the tune jumps system provided an accurate estimation of polarization gains and the optimum settings that would improve the performance of the AGS
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Ibarrart, Loris. „Description en espaces de chemins et méthode de Monte Carlo pour les transferts thermiques couplés dans les structures fluides et solides, une approche compatible avec l'informatique graphique“. Thesis, Ecole nationale des Mines d'Albi-Carmaux, 2020. http://www.theses.fr/2020EMAC0009.
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Les travaux présentés dans ce manuscrit abordent la thématique du couplage des transferts thermiques. En particulier, ils s’inscrivent dans une réflexion actuelle autour de l’échantillonnage de chemins aléatoires par la méthode de Monte Carlo. Ce choix est justifié par un souhait d’obtenir des algorithmes ne présentant pas de contraintes sur la complexité des géométries étudiées. En effet, l’utilisation conjointe de ce type d’approches statistiques et des outils d’accélération de la synthèse d’image (grilles accélératrices) permet d’ores et déjà une résolution exacte du transfert radiatif en géométrie quelconque. Pour les transferts thermiques de type diffusif, l’exactitude des approches en espaces de chemins n’est atteignable que pour des configurations simples. On choisit donc d’utiliser des chemins statistiques approchés pour rendre compte de ce type de phénomènes thermiques dans des géométries quelconques. Parmi les choix disponibles, on retiendra des espaces de chemins construits autour du lancer de rayon, qui permettront donc de bénéficier de l’ensemble des avantages des outils développés par la communauté de l’informatique graphique. Une preuve de concept de l’insensibilité du temps de calcul au nombre de pores de la résolution thermique d’un échangeur poreux par l’utilisation de marches aléatoires conducto-convecto-radiatives sera ainsi présentée. Au-delà de ce résultat, une analyse du comportement de la méthode sur des échangeurs à canaux permettra de classifier des situations d’insensibilité, ou pas, à la complexité des milieux poreux étudiés. La capacité à expliquer les limites de cette insensibilité et le comportement de ce temps de calcul fera alors émerger un concept d’épaisseur thermique homologue à la problématique de l’épaisseur optique en transfert radiatifThe present manuscript deals with the coupling of thermal heat transfers. More precisely, it adresses this coupling by making use of the Monte Carlo method and the sampling of random paths. This choice was made in the perspective of building algorithms that do not present constraints regarding the complexity of the studied geometry. Indeed, the combined use of this kind of statistical approaches, and acceleration tools coming from the image synthesis community, already allowed for an exact resolution of radiative transfer in arbitrary geometries. Regarding diffusive heat transfers, exact results using random paths are only achievable in academic configurations. Thus, approximate random paths are commonly used to account for this kind of thermal transport. Among the possible choices, we will use random paths built on ray tracing, therefore allowing to benefit once again from all the advantages of the tools developed in computer graphics. A proof of concept of the insensitivity of the computation time of the resolution of thermal transfers in porous exchangers to the number of pores by making use of conducto-convecto-radiative random paths will be presented. Beyond this result, an analysis of the behaviour of this method in ducts heat exchangers will allow to clarify when this kind of insensitivity can indeed be observed. This analysis will induce the concept of thermal thickness, by analogy with optical thickness for radiative transfer
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Sarthou, Arthur. „Méthodes de domaines fictifs d'ordre élevé pour les équations elliptiques et de Navier-Stokes. Application au couplage fluide-structure“. Phd thesis, Université Sciences et Technologies - Bordeaux I, 2009. http://tel.archives-ouvertes.fr/tel-00460206.
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La simulation de cas réalistes d'écoulements ou de transferts thermiques implique souvent l'utilisation d'obstacles ou d'interfaces de forme complexe. De part leur manque de flexibilité, les maillages structurés ne sont pas initialement adaptés au traitement d'interfaces irrégulières, ces dernières coïncidant rarement avec les lignes du maillage. Afin de permettre à l'approche structurée de traiter des interfaces complexes avec précision, des méthodes dites de domaines fictifs sont nécessaires. La première contribution de cette thèse est une nouvelle méthode de travail sur maillage curviligne structuré qui permet de réutiliser de nombreuses méthodes fonctionnant initialement sur des maillages cartésiens sur maillages curvilignes. Nous avons ensuite mis au point deux nouvelles méthodes de domaines fictifs : la méthode de pénalisation de sous-maille (PSM) pour la gestion des frontières immergées pour les équations elliptiques et de Navier-Stokes et la méthode d'interface immergée algébrique (IIA) pour les problèmes d'interfaces immergées pour les équations elliptiques. L'un des intérêts de ces deux méthodes à l'ordre deux en espace est leur simplicité. Ces différents développements ont finalement été appliqués à des cas de couplage fluide-structure académiques et réalistes (sédimentation d'un cylindre, hydroplanage d'un pneu, écoulements dans une tête de forage et convection naturelle dans la grotte de Lascaux).
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Navrátil, Paul Arthur. „Memory-efficient, scalable ray tracing“. Thesis, 2010. http://hdl.handle.net/2152/ETD-UT-2010-08-1982.
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Ray tracing is an attractive rendering option because it can produce high quality images that faithfully represent physically-based phenomena. Its embarrassingly
parallel nature makes it a natural choice for rendering large-scale scene data, especially on machines that lack specialized graphics hardware. Unfortunately, the traditional recursive ray tracing algorithm is exceptionally memory inefficient for large scenes, especially when using a shading model that generates incoherent secondary rays. Queueing ray tracers have been shown to control scene state under these conditions, but they allow ray state to grow unchecked. Instead, we propose a ray tracing framework that controls both ray and scene state by dynamically adjusting the rendering algorithm to meet memory requirements. Our dynamic scheduling framework generalizes recursive and queueing tracers into a spectrum of ray schedules that can vary the active amount of ray and scene data in order to match the characteristics of the hardware’s memory system.
This dissertation describes our dynamic ray scheduling approach that operates on memory-bound work units, which consist of both rays and scene data. It builds these work units by tracing rays iteratively and queueing them in spatial regions along with nearby data. By dynamically scheduling these work units, our approach can reduce data loads and improve total runtime by 2x to 30x . In addition, we show that our algorithm scales across more than 1000 distributed processors, which is an order of magnitude larger than previously published results. Our approach enables the use of complex lighting models on large data, particularly
scientific data, which improves image quality and thereby improves the scientific insights possible.text
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Yang, Wen Tai, und 楊文泰. „A New Ray Tracing Algorithm for Radiosity under Dynamic Environments“. Thesis, 1995. http://ndltd.ncl.edu.tw/handle/76607621726389778432.
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碩士中原大學
資訊工程研究所
83
In the study of computer graphics, radiosity could simulate the real environment. It is important to produce a computer synthetical image by radiosity. But the effect of ray tracing is better than traditional radiosity on specular reflection and occlusion detection. Therefore, it is a new research tendency to combine the ray tracing and the radiosity to simulate real environment. A new method will be proposed to simulate real environment realistically and quickly. The radiosity is a powerful method for simulating the light interre- flection between diffuse surfaces. The brightness of a surface is determined by the energy included in the surface. So images generated by the radiosity are viewer-independent. However, it is time consumming to re-compute the radiosity when the geometry of environment is changed. Moreover, the radiosity approach depended on the hemi-cube algorithm to determine form- factor and occlusion previously.A little error would be occurred due to the resolution of hemi-cube and sampling process. A new ray tracing algorithm is presented to compute form- factor and to judge occlusion instead of hemi-cube method. The spatial subdivision and redistribution algorithm are combined into our new ray tracing algorithm to solve the problem of radiosity under dynamic environment. The method not only find the coherence in dynamic environment but also reduce the detection time of ray-object intersections. Moreover, it increase the accuracy of form-factor. Furthermore, our method is more efficient than known algorithms.
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Hong, Qi-Hao, und 洪啟豪. „2D Grid Based Acceleration Methods for Ray Tracing in Dynamic Scenes“. Thesis, 2007. http://ndltd.ncl.edu.tw/handle/03911752897014821534.
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Huai-En, Jen, und 任懷恩. „An Improved Method for 2D Grid Based Ray Tracing in Dynamic Scenes“. Thesis, 2008. http://ndltd.ncl.edu.tw/handle/38732168271758108537.
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Wei, Chen Shih, und 陳世偉. „Advanced 2D Grid Based Acceleration Methods for Ray Tracing in Dynamic Scenes“. Thesis, 2008. http://ndltd.ncl.edu.tw/handle/78126787271463911558.
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Chang, Chen-Hao, und 張誠豪. „Algorithm and System Architecture Design of Whitted-style Ray Tracing for Dynamic Scenes“. Thesis, 2009. http://ndltd.ncl.edu.tw/handle/22168146091711066058.
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碩士臺灣大學
電子工程學研究所
98
Ray tracing is an algorithm for synthesizing a realistic image in 3D computer graph- ics. The advantage of this algorithm is supporting not only the visibility of scene and shadow but also indirect lighting effects such as reflection and refraction. However, the computation complexity of ray tracing is very large due to large number of ray- primitive intersections especially for rendering the indirect lighting effect. Although there are many accelerating algorithms using data special structures to accelerate the tracing process, the real time performance is still hard to achieve. Besides, the inter- active applications with 3D graphics are popular such as 3D gameing, where the scene may be changed in every frame. This means that the data structure building time is also an important issue for real time rendering. Aiming to solve these problems, this thesis proposes a system architecture which uses ASIC to accelerate ray tracing pro- cess. Instead of considering the primary rays only, secondary rays are also considered to render more realistic scenes, which is called as Whitted-style ray tracing. By using packet-based ray traversal algorithm and frustum culling not only in primary rays but also in shadow rays and secondary rays, the steps of ray traversing are reduced. Be- sides, aiming to support interactive applications, the data structure should be changed dynamically. Instead of rebuilding data structure every frames, we use updating based algorithms such as refit and insertion to update the data structure of the previous frame. By using updating based algorithm, the building time of new data structure is short and the traversing result is correct after the scene changes. In the hardware architecture of this system, multi-threading is used. Moreover, the computation for finding the inser- tion positions in insertion algorithm and shading are integrated into a specific unit to enable hardware sharing. This architecture is System-on-a-chip composed of CPU, our rendering engine, system memory and other peripherals. For an image in resolution of 352 288, the system can achieve 3–15 frames per second and also support dynamic scenes.
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Jung, Lin Chun, und 林俊戎. „A Method for Accelerating Ray Tracing without Data Structure Reconstruction in Dynamic Scenes“. Thesis, 2008. http://ndltd.ncl.edu.tw/handle/30575454892896295764.
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Wan, Ting Yang, und 楊琬婷. „Ray Tracing Dynamic Scenes by Restructuring the Bounding Volume Hierarchy with Hybrid Nodes“. Thesis, 2008. http://ndltd.ncl.edu.tw/handle/68853535699461047762.
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Koch, Max. „Laser cavitation bubbles at objects: Merging numerical and experimental methods“. Doctoral thesis, 2020. http://hdl.handle.net/21.11130/00-1735-0000-0005-1516-B.
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