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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Raytracing i Kanalmodellsimuleringar med GPU:er / Raytracing in Channel Model Simulations Using GPUs

Sjökvist, Emil, Landberg, Simon January 2022 (has links)
Eftersom att dataanvändningen runt om i världen är något som hastigt ökar måste tekniken hänga med den ständigt höga efterfrågan på data. 5G är en ny teknik som utvecklas för fullt och redan finns på vissa ställen i världen. Innan man installer arantenner och implementerar 5G i samhället skulle det underlätta om man först på något sätt skulle kunna simulera hur signalerna kommer att röra sig och träffa mottagare beroende på var man sänder ifrån och på så sätt få en uppfattning om hur och var det vore optimalt att installera 5G­sändare. Målet för projektet är att ta fram metoder, mjukvara och miljöer för att kunna utföra denna simulering samt använda en raytracer för att på ett så verklighetstroget sätt som möjligt skapa virtuella radiovågor. För att uppnå detta utfördes mycket forskning kring vad för mjukvara som är optimalt att använda för projektets ändamål och en stor mängd analysering av kodsamt experimentation inuti OptiX för att få förståelse för hur strålar genereras, färdas och interagerar i scenerna. Slutligen lyckades framtagning av all programvara som behövs för att utveckla simuleringen samt kan strålar skickas och användas i scenen med viss funktionalitet. Dock behövs vidare utveckling på projektet för att visualisera strålarna på ett korrekt sätt samt implementera flera av de fysiska egenskaperna.
22

Accurate Positioning in Urban Canyons with Multi-frequency Satellite Navigation

Ollander, Simon 07 December 2020 (has links)
No description available.
23

Realistická vizualizace alkoholických nápojů pomocí distribuovaného raytracingu / Realistic Visualisation of Alcoholic Beverages Using Distributed Raytracing

Fabík, Jiří January 2013 (has links)
This work is about a realistic visualization technique called raytracing. It studies its original form, its extensions and optimizations. Raytracing casts rays through pixels and follows their propagation in the scene, according to the physical laws. It enables rendering of correct shadows, reflections and refractions. Distributed raytracing serves for better visualization and advanced effects. One ray is replaced with a beam of rays that allows soft shadows, fuzzy translucency, depth of field and antialiasing. With the increasing number of rays, the render time rises as well, so it is needed to use some optimization techniques and tools. A way of using this rendering method for visualization of alcoholic beverages is also described.
24

Raytracing virtuálních grafických scén / Raytracing of Virtual Graphics Scenes

Rypák, Andrej January 2012 (has links)
This thesis is dedicated to ray tracing based rendering methods, primarily the original ray tracing. Besides introducing a brief historical overview of algorithms from the family, it presents all the essential tools, techniques and physics needed for designing a rendering application in detail. A significant part of the document consists of an implementation of a photorealistic rendering application for interactive graphics 3D virtual scenes. The focus is on rendering without using any additional model information. The thesis includes descriptions and explanations of specific problems and their solutions.
25

Bezsnímkové renderování / Frameless Rendering

Najman, Pavel January 2012 (has links)
The aim of this work is to create a simple raytracer with IPP library, which will use the frameless rendering technique. The first part of this work focuses on the raytracing method. The next part analyzes the frameless rendering technique and its adaptive version with focus on adaptive sampling. Third part describes the IPP library and implementation of a simple raytracer using this library. The last part evaluates the speed and rendering quality of the implemented system.
26

Zobrazování scény v moderních počítačových hrách / Scene Rendering in Modern Computer Games

Wilczák, Martin January 2011 (has links)
This thesis describes methods for lighting calculations of large scenes used in modern computer games. Forward shading and deferred shading methods are discussed and compared. Capabilities of raytracing are shortly described. There are some information about various methods for casting shadows, simulation of particle systems and applying post-processing effects. In the end there is a design of architecture for rendering complex scenes with use of XNA and description of implementation used in resulting game.
27

Scheimpflug Records without Distortion – A Mythos?

Huebscher, Hans-Joachim, Fink, Wolfgang, Steinbrück, Dagmar, Seiler, Theo January 1999 (has links)
The Scheimpflug principle was recommended as allowing distortion-free imaging; however, a detailed analysis reveals geometrical errors as well as distortions arising from absorption of light along the optical pathway. Correction formulas and factors will be presented and applied to the biometry of the eye. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.
28

Applications and Acceptance of Solar UV Technologies for Drinking Water Disinfection in Low-Income Settings

Margaret M Busse (11547811) 13 October 2021 (has links)
<p>Access to potable water has been identified as a basic human right, yet it is estimated that 2.2 billion people worldwide do not have access to safely managed drinking water. Many of those without access live in regions of the world with abundant sunlight, which can be utilized both directly and indirectly to disinfect drinking water. Directly it can be used in solar water disinfection (SODIS) applications, and indirectly it can be collected by solar panels to power commercially available UV reactors. Herein, we study the potential for direct and indirect water disinfection technologies to be used and adopted in developing countries, with specific insight into their application in the Dominican Republic and Kenya.</p><p>The amount of available ambient solar UV was both measured and modelled to inform design and modelling of treatment systems, and to understand whether real-time monitoring of ambient UV is required for the operation of systems directly utilizing UV for disinfection. The model both over- and under-predicted measurements of ambient UV, and did so at inconsistent rates, most likely as a result of cloud cover. This indicates that real-time monitoring of ambient UV would most likely be needed for disinfection methods directly using solar UV for inactivation in order to ensure water was always dosed properly.</p><p>The amount of available ambient solar UV was input into a raytracing model (Photopia, LTI Optics) to simulate the amplification of solar spectral irradiance within a continuous-flow compound parabolic collector (CPC). This informed design improvements that allowed for an increase in flow rate through the system, which was supported by field testing of the reactor. Further, two commercial UV reactors, one utilizing a low-pressure (LP) lamp and the other utilizing an LED source, were tested in the lab to verify their ability to inactivate <i>S. typhimurium </i>LT2. The LP-based device outperformed the LED-based device, which was unable to achieve over 2-log<sub>10</sub> units of inactivation under any of the studied conditions.</p><p>A life cycle assessment was conducted to assess the environmental impact of the three studied UV reactors against traditional chlorination and water delivery methods. Chlorine had the lowest impact in every category under all of the studied conditions, but there have been many barriers reported on the lack of adoption of chlorine. So the next lowest impact technology was evaluated at the community scale, which was the LP reactor. Therefore, the LP reactor was installed in study communities in both the Dominican Republic and Kenya. In the Dominican Republic, the systems suffered from a lack of boots on the ground, and faced technical, social, and economic barriers to adoption. In Kenya, the project suffered from similar constraints, that did not allow for project assessment. This work not only addresses the barriers faced in both of these projects, but provides suggestions for improving similar projects in the future.</p>
29

Bezsnímkové renderování / Frameless Rendering

Krupička, Vojtěch January 2012 (has links)
This master's thesis deals with the problem of real-time rendering of computer graphics using the method of frameless rendering} as counterpart to the traditional way, which is based on switching between two output buffers. Frameless rendering method is defined and studied in greater depth and its adaptive variant, which delivers better output quality without a~significant reduction of latency, is described in detail. In addition, this thesis describes the implementation of the application which has been developed to demonstrate the principle and functionality of the frameless rendering on the selected scenes. It also includes evaluation of performed tests focused to the output quality.
30

Raytracing na GPU / Raytracing on GPU

Straňák, Marek January 2011 (has links)
Raytracing is a basic technique for displaying 3D objects. The goal of this thesis is to demonstrate the possibility of implementing raytracer using a programmable GPU. The algorithm and its modified version, implemented using "C for CUDA" language, are described. The raytracer is focused on displaying dynamic scenes. For this purpose the KD tree structure, bounding volume hierarchies and PBO transfer are used. To achieve realistic output, photon mapping was implemented.

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