Many contemporary types of 3D design software use some form of environment mapping, where the environment surrounding the 3D object is rendered to create a panoramic view similar to what we would see in the real world. This not only serves to make the scene look more realistic, but also helps to calculate light effects within the scene. Although environment mapping has been around for a while, and today's methods are highly optimized, they are still not trivially cheap to do, especially on lower end hardware. Our thesis investigates how an environment mapping method currently in use by our client can be further optimized. This optimization intends to serve two main purposes - to improve performance for clients with lower quality hardware and to allow users to increase texture resolution without extra cost on performance. Two alternative methods are presented, both based somewhat loosely on the idea of occlusion culling. The two approaches are then tested and compared to the original solution in terms of speed, memory utilization and network performance. Although both approaches show promise and outperform the original solution in some of the tests, they still lack the versatility of the original solution and suffer from some major flaws, making them less appealing alternatives for the general customer. The first approach managed to perform well in all three areas of measurement, but suffers a drawback which limits its use in a real-world scenario. The second approach did not have the same drawback which may make it a more viable option. However, the results of the second approach were not as positive as the first one. With that said, it showed some promise for users who do their rendering on a separate server. While this solution may not yet be viable for the general user, it may serve well for users with more unique needs. To make this approach a viable solution for the general user improvements in regards to rendering speed and GPU utilization will have to be investigated further.

Att detektera och eliminera dolda ytor är viktigt när grafiska applikationer blir mer komplexa och detaljerade. En teknik som används till det är occlusion culling och olika typer av algoritmer har tagits fram för att möjliggöra den tekniken. Occlusion culling innebär att hitta objekt som har stor potential att dölja delar av en scen. Dessa objekt kallas för occluders. I den här rapporten så undersöks möjligheten att använda olika stor mängd av occluders i en algoritm och hur det påverkar olika typer av spelscener. Tre olika spelscener har satts upp i Unity som skiljer sig i hur de är uppbyggda. Effekten av occlusion culling i scenerna visar på att det kan vara en teknik bättre lämpad för vissa typer av spel. Rapporten visar också på en möjlighet att forska vidare på valet av en lämplig mängd med occluders.

Made available in DSpace on 2014-12-17T14:55:20Z (GMT). No. of bitstreams: 1 IcaroLLC_TESE.pdf: 6782954 bytes, checksum: cb0650b733e29c9e5e7032cef110a519 (MD5) Previous issue date: 2014-01-22 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / We revisit the problem of visibility, which is to determine a set of primitives potentially visible in a set of geometry data represented by a data structure, such as a mesh of polygons or triangles, we propose a solution for speeding up the three-dimensional visualization processing in applications. We introduce a lean structure , in the sense of data abstraction and reduction, which can be used for online and interactive applications. The visibility problem is especially important in 3D visualization of scenes represented by large volumes of data, when it is not worthwhile keeping all polygons of the scene in memory. This implies a greater time spent in the rendering, or is even impossible to keep them all in huge volumes of data. In these cases, given a position and a direction of view, the main objective is to determine and load a minimum ammount of primitives (polygons) in the scene, to accelerate the rendering step. For this purpose, our algorithm performs cutting primitives (culling) using a hybrid paradigm based on three known techniques. The scene is divided into a cell grid, for each cell we associate the primitives that belong to them, and finally determined the set of primitives potentially visible. The novelty is the use of triangulation Ja 1 to create the subdivision grid. We chose this structure because of its relevant characteristics of adaptivity and algebrism (ease of calculations). The results show a substantial improvement over traditional methods when applied separately. The method introduced in this work can be used in devices with low or no dedicated processing power CPU, and also can be used to view data via the Internet, such as virtual museums applications / N?s revisitamos o problema de visibilidade, que visa determinar um conjunto de primitivas potencialmente vis?veis em um conjunto de dados geom?tricos representados por uma estrutura de dados, por exemplo uma malha de pol?gonos ou de tri?ngulos, propondo uma solu??o para acelerar o processamento em aplica??es em visualiza??o tridimensional. Introduzimos uma estrutura enxuta, no sentido de abstra??o e redu??o de dados, que pode ser usada para aplica??es online e interativas. O problema de visibilidade ? especialmente importante na visualiza??o 3D de cenas representadas por grande volume de dados, em que n?o ? interessante manter todos os pol?gonos da cena em mem?ria. Isso implicaria em um maior tempo gasto na renderiza??o, ou sendo at? mesmo imposs?vel mant?-los todos em volumes imensos de dados. Nestes casos, dada uma posi??o e uma dire??o de visualiza??o, o objetivo principal ? determinar e carregar o m?nimo poss?vel de primitivas (pol?gonos) da cena, visando acelerar a etapa de renderiza??o. Para este prop?sito, nosso algoritmo executa o corte de primitivas (culling) usando um paradigma h?brido baseado em tr?s modelos conhecidos. A cena ? subdividida em c?lulas de uma grade, sendo associada a cada uma dessas c?lulas as primitivas pertencentes a elas, e finalmente determinado o conjunto de primitivas potencialmente vis?veis. A novidade ? o uso da triangula??o J a 1 para criar a subdivis?o em grade. Escolhemos esta estrutura devido ?s suas caracter?sticas relevantes de adaptatividade e algebrismo (facilidade de c?lculos). Os resultados mostram uma melhoria substancial sobre os m?todos tradicionais quando aplicados separadamente. O m?todo introduzido neste trabalho pode ser usado em dispositivos sem processador dedicado ou com baixo poder de processamento, e ainda, pode ser utilizado para visualizar dados atrav?s da Internet, tal como em aplica??es de museus virtuais

Ultracold atoms have been successfully used to study numerous systems, previously unaccessible, but a precise control over the atom number of the sample still remains a challenge. This dissertation describes our progress towards achieving Fock states of atoms. The first three chapters cover the basic physics necessary to understand the techniques we use in our lab to manipulate atoms. We then summarize our experimental results from an earlier setup where we did two experiments. In the first experiment we compare the transport of cold atoms and a Bose Einstein Condensate (BEC) in a periodic potential. We find a critical potential height beyond which the condensate behavior deviates significantly from that of thermal atoms. In the second experiment we study the effect of periodic temporal kicks by a spatially periodic potential on a BEC in a quasi one dimensional trap. We observe a limit on the energy that the system can absorb from the kicks, which we conclude is due to the finite height of the trap rather than quantum effects. The majority of the dissertation discusses our experimental setup designed to produce Fock states. The setup is designed to use the method of laser culling to produce Fock states. We are able to create a BEC and transport it into a glass cell 25 cm away. We tried different innovative methods to reduce vibrations during transport before finally settling to a commercial air bearing translation stage. We create a high confinement one dimensional optical trap using the Hermite Gaussian TEM₀₁ mode of a laser beam. Such a trap gives trapping frequencies comparable to an optical lattice and allows us to create a single one dimensional trap. We creating the TEM₀₁ mode using an appropriate phase object (phase plate) in the path of a TEM₀₀ mode beam. The method for producing the phase plate was very well controlled to obtain a good quality mode. Once the atoms are loaded into this one dimensional trap we can proceed to do laser culling to observe Sub-Poissonian number statistics and eventually create Fock states of few atoms. Finally, we describe a novel method to create a real time tunable optical lattice which would provide us with the ability of spatially resolved single atom detection. The majority of the dissertation discusses our experimental setup designed to produce Fock states. The setup is designed to use the method of laser culling to produce Fock states. We are able to create a BEC and transport it into a glass cell 25 cm away. We tried different innovative methods to reduce vibrations during tr₀ansport before finally settling to a commercial air bearing translation stage. We create a high confinement one dimensional optical trap using the Hermite Gaussian TEM₀₁ mode of a laser beam. Such a trap gives trapping frequencies comparable to an optical lattice and allows us to create a single one dimensional trap. We creating the TEM₀₁ mode using an appropriate phase object (phase plate) in the path of a TEM₀₀ mode beam. The method for producing the phase plate was very well controlled to obtain a good quality mode. Once the atoms are loaded into this one dimensional trap we can proceed to do laser culling to observe Sub-Poissonian number statistics and eventually create Fock states of few atoms. Finally, we describe a novel method to create a real time tunable optical lattice which would provide us with the ability of spatially resolved single atom detection. The majority of the dissertation discusses our experimental setup designed to produce Fock states. The setup is designed to use the method of laser culling to produce Fock states. We are able to create a BEC and transport it into a glass cell 25 cm away. We tried different innovative methods to reduce vibrations during transport before finally settling to a commercial air bearing translation stage. We create a high confinement one dimensional optical trap using the Hermite Gaussian TEM₀₁ mode of a laser beam. Such a trap gives trapping frequencies comparable to an optical lattice and allows us to create a single one dimensional trap. We creating the TEM₀₁ mode using an appropriate phase object (phase plate) in the path of a TEM₀₀ mode beam. The method for producing the phase plate was very well controlled to obtain a good quality mode. Once the atoms are loaded into this one dimensional trap we can proceed to do laser culling to observe Sub-Poissonian number statistics and eventually create Fock states of few atoms. Finally, we describe a novel method to create a real time tunable optical lattice which would provide us with the ability of spatially resolved single atom detection. The majority of the dissertation discusses our experimental setup designed to produce Fock states. The setup is designed to use the method of laser culling to produce Fock states. We are able to create a BEC and transport it into a glass cell 25 cm away. We tried different innovative methods to reduce vibrations during transport before finally settling to a commercial air bearing translation stage. We create a high confinement one dimensional optical trap using the Hermite Gaussian TEM₀₁ mode of a laser beam. Such a trap gives trapping frequencies comparable to an optical lattice and allows us to create a single one dimensional trap. We creating the TEM₀₁ mode using an appropriate phase object (phase plate) in the path of a TEM₀₀ mode beam. The method for producing the phase plate was very well controlled to obtain a good quality mode. Once the atoms are loaded into this one dimensional trap we can proceed to do laser culling to observe Sub-Poissonian number statistics and eventually create Fock states of few atoms. Finally, we describe a novel method to create a real time tunable optical lattice which would provide us with the ability of spatially resolved single atom detection. / text

[pt] Neste trabalho aplicamos o método de oclusão implícita para acelerar o tempo de cálculo e renderização de isosuperfícies em dados volumétricos regulares. Dado um campo escalar contínuo f sobre um domínio D (onde Dé convexo) e um isovalor w, a oclusão implícita explora a continuidadede f para determinar os limites de visibilidades sem a necessidade de calcular a isosuperfície explicitamente. Aplicamos esta técnica para obter também as silhuetas visíveis das isosuperfícies. / [en] In this work we apply the Implicit Occluders method for optimizing the computation and rendering of isosurfaces in regular volumetric data. Given a continuous scalar field f over a domain D and an isovalue w, Implicit Occluders exploits the continuity of f to determine visibility bounds without the need for computing the isosurface explicitly. We apply this technique to obtain also the visible silhouettes of isosurfaces.

Introdução: A premissa do programa nacional de controle da leishmaniose visceral (LV) é que a doença humana esteja relacionada com a canina, sendo o controle do reservatório canino um dos focos do programa. Objetivos: Mensurar a taxa de incidência da LV em humanos, relacionando-a com as coberturas do controle químico e do reservatório canino. Relacionar a soroprevalência canina com características dos cães e de seus tutores. E avaliar a eficácia da eutanásia de cães soropositivos no controle da infecção canina. Métodos: Os casos humanos e os domicílios com cães soropositivos registrados no período de 2007 a 2015 no município de Araçatuba, estado de São Paulo, foram geocodificados e calculadas a soroprevalência canina, a taxa de incidência humana e as coberturas das atividades de inquérito sorológico, eutanásia e controle químico. A associação entre as variáveis foi avaliada por comparação de mapas, por regressão linear e pela função K de Ripley. Um estudo transversal foi conduzido entre 2015 e 2016, nos municípios de Araçatuba e Birigui, tendo como base uma amostra da população canina. A soroprevalência foi modelada por regressão logística em uma abordagem geoestatística usando a aproximação de Laplace integrada aninhada para inferência bayesiana. Dados secundários e dos inquéritos realizados foram utilizados para elaborar e calibrar modelos dinâmicos. Resultados: Observou-se no município de Araçatuba a diminuição da taxa de incidência LV e da soroprevalência canina, apesar das coberturas de controle terem sido baixas no mesmo período estudado. O inquérito sorológico revelou uma soroprevalência canina de 8% em Araçatuba e 4% em Birigui. Em Araçatuba a ocorrência de cães soropositivos foi associada à domicílios que tiveram mais de 10 cães ao longo do tempo, domicílios com histórico de cães com a infecção ou que morreram por outras causas não naturais, e à permanência dos cães no peridomicílio ao longo do dia. Foi observada dependência espacial (46 m) entre as observações. Considerando controle contínuo e um esforço das atividades de inquérito sorológico três vezes maior que a média do observado em Araçatuba e duas vezes maior em Birigui, as atividades relacionadas à eutanásia de cães com diagnóstico positivos possibilitariam, em teoria, o controle da infecção canina. Conclusões: A diminuição da LV ao longo do tempo está relacionada com as ações de controle, uma vez que pequenas alterações na dinâmica da infecção canina têm importância epidemiológica. O encontro de dependência espacial entre os domicílios com casos caninos em pequenas distâncias reforça a existência de um padrão local da transmissão da infecção entorno dos domicílios, relacionado com as características do vetor. A eutanásia de cães soropositivos, em teoria, é capaz de controlar a infecção canina, porém, este resultado desse ser entendido com cautela, dada a complexidade operacional desta medida e as questões éticas relacionadas. Novos estudos precisam ser desenvolvidos para uma melhor compreensão se fatores além das atividades de controle estariam envolvidos na diminuição da incidência da LV. Faz-se necessário planejamento a longo prazo das ações de controle e investimento em pesquisas sobre o custo-efetividade de outras medidas que auxiliem no controle da LV. / Background: The assumption of visceral leishmaniasis (VL) control program is that human disease (HVL) is related to canine infection (CanL), and that supports the culling of infected dogs. Objectives: Estimate the coverage of visceral leishmaniasis (VL) control measures and to relate them to the occurrence of HVL in an endemic urban area (Araçatuba, SP). Determine the CanL seroprevalence and to evaluate its relationship with the characteristics of dogs and their owners. Evaluated the culling dogs efficacy in controlling the canine infection. in the municipalities of Araçatuba and Birigui, state of São Paulo, Brazil. Methods: The cases of HVL and households with seropositive dogs registered in the period from 2007 to 2015 were geocoded the coverage of the serological inquiry, culling dogs and chemical spaying, canine seroprevalence and HVL incidence rates were calculated. The relationship between CanL, HVL and control measures was evaluated by map comparison, by linear regression and was also assessed using the Ripley K function. A cross-sectional study was conducted between 2015 and 2016, based on a sample of the canine population. Seroprevalence was modelled by logistic regression in a geostatistical approach using the integrated nested Laplace approximation for Bayesian inference. The spatial component was modelled by a Gaussian field, using a stochastic partial differential equation approach. Secondary data and the surveys were used to elaborate and calibrate dynamic models of canine disease transmission. Results: Verified the decrease of HVL and the CanL in Araçatuba over time, even in low coverage of control measures. The CanL seroprevalence was 8% in Araçatuba and 4% in Birigui. The occurrence of a seropositive dog in Araçatuba was associated with the presence of more than 10 dogs living in the same house, house with dogs that previously died of VL or died of other unnatural causes, and the place of dogs stayed during the day. Spatial dependence among observations occurred within about 46 m. Considering a continuous control and a serological survey effort three times higher than the average of the observed in Araçatuba and twice as high in Birigui, the activities related to culling dogs is effective in controlling canine infection. Conclusions: The observation of VL decrease over time may be related to control measures. The short-distance spatial dependence could be related to the vector characteristics, producing a local neighbourhood VL transmission pattern. The culling dogs were effective in controlling the disease in the dogs\' population. However, this result should be understood with caution given the operational complexity of this measure and related ethical issues. New studies need to be developed for a better understanding if factors other than control activities would be involved in reducing the incidence of VL. It is necessary in addition to long-term planning of the control actions carried out by the program, investment in researches that evaluate the cost-effectiveness of other measures that may help in the control of VL.

This research focuses on the utilization of occlusion culling for the real-time visualization of distributed virtual urban environments. Today&#039 / s graphics hardware renders all the primitives in any order and uses z-buffer to determine which primitives are visible on a per-pixel basis. However, visibility is computed in the last stage of rendering pipeline and every rendered primitive is not visible in the final image. Early culling of the invisible primitives in a complex scene is valuable for efficiency in the conventional rendering pipeline. This may reduce the number of primitives that will be processed in the rest of the pipeline. In this thesis, we propose an efficient visibility estimation method for distributed virtual urban environments. The proposed method is based on occlusion culling to identify and cull the occluded parts of the scene. This not only computes conservative potential visible set (PVS) for each client but also assures the computed PVS to be available at the client on-time and reduces the network traffic by grouping the clients which may see each others dynamically.

This thesis describes the development of a distributed occlusion culling solution for complex generic scenes. Moving these calculations onto a second computer should decrease the load on the actual rendering system and therefore allow higher framerates. This work includes an introduction to parallel rendering systems and discussion of suitable culling algorithms. Based on these parts, a client-server system for occlusion culling is developed. The test results of a prototypical implementation form the last part of this thesis.

This dissertation presents the development and implementation of two novel experimental techniques for controlling atom number and phase-space density in cold atomic gases. The first experiment demonstrates the method of single-photon cooling, an optical realization of Maxwell's demon, using an ensemble of rubidium atoms. Single-photon cooling increases the phase-space density of a cloud of magnetically trapped atoms, reducing the entropy of the ensemble by irreversibly transferring atoms through a one-way wall via a single-photon scattering event. While traditional laser cooling methods are limited in their applicability to a small number of atoms, single-photon cooling is much more general and should in principle be applicable to almost all atoms in the periodic table. The experiment described in this dissertation demonstrates a one-dimensional implementation of the cooling scheme. Complete phase-space compression along this dimension is observed. The limitations on the cooling performance are shown to be given by trap dynamics in the magnetic trap. The second part of this dissertation is dedicated to the experiment built to control the atom number of a degenerate Fermi gas on a single particle level. Creating Fock states of atoms with ultra-high fidelity is a mandatory step for studying quantum entanglement on a single atom level. The experimental technique implemented to control the atom number in this experiment is called laser culling. Decreasing the trapping potential reduces the atom number in a controlled way, giving precise control over the number of atoms remaining in the trap. This dissertation details the design and construction of this experiment and reports on the progress towards the creation of neutral lithium Fock states. / text

Uždengtos geometrijos atrinkimas – tai būdas nustatyti geometriją, kuri yra uždengta su kita geometrija ir dėl to gali būti nevaizduojama, nes neturės jokios įtakos vaizduojamam paveikslui. Tokios geometrijos nevaizdavimas didina vaizdavimo procedūros našumą. Egzistuoja eilė uždengtos geometrijos nustatymo būdų, iš kurių vienas yra hierarchinis uždengtos geometrijos atrinkimo algoritmas. Šiame darbe yra analizuojami uždengtos geometrijos nustatymo būdai bei nagrinėjamos pasirinkto algoritmo veikimo spartinimo galimybės panaudojus DirectCompute technologiją. Ši technologija yra Microsoft DirectX 11 bibliotekų rinkinio dalis, kuri leidžia panaudoti grafinį procesorių bendro pobūdžio skaičiavimams. Darbe iškeltų tikslų pasiekimui yra realizuotos kelios bazinės algoritmo versijos modifikacijos, atliekami modifikuotų versijų veikimo laiko bei įvairių veikimo laiką įtakojančių faktorių tyrimai. Yra aptariami gauti rezultatai bei pateikiamos išvados. / Occlusion culling is a method, which task is to determine geometry occluded with other geometry. Rendering this geometry is useless because it wouldn’t impact rendered picture in any way, so discarding it will improve render time. There are various methods to determine occluded geometry and hierarchical occlusion culling is one of them. This document contains a short summary of these methods, but it’s mainly focused on improving hierarchical occlusion culling algorithm performance by making use of DirectCompute technology. This technology is a part of Microsoft DirectX 11 API, which helps the developer to use graphics processor for general-purpose computation. Main goal is reached by performing in-depth analysis of implemented hierarchical occlusion culling algorithm modifications. This analysis consists of both general performance and various performance-related analyses. Further down the road conclusions and recommendations are given based on performed work and overall results.