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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.
481

Real-Time Tessellation A Region of Interest Based Technique Suited for Game Applications / Realtids tesselering, en regionsbaserad teknik för spel

Liljekvist, Pontus Holmertz, Zsigmond, Andreas January 2013 (has links)
While the games industry grows, the need for visually appealing graphics increase. This drives the demand for new hardware and the development of new techniques forward. With the latest generation of 3D graphic APIs the new rendering pipeline technique tessellation was announced. With each generation of games getting more advanced, the demand for highly detailed models increase. This leads to a higher workload for the GPU. The purpose of this thesis is to research the fi eld of tessellation and develop a prototype to optimize the tessellation pipeline. The prototype is designed to help reduce the number of generated triangles by dividing the mesh into regions, each region with its own tessellation factor. The prototype implementation supports both manual and automatic generation of these regions. A new fi le format was developed to support the region data. The implementation was split into three parts; one Python based Maya plug-in used for preparing the model for exporting, one exporter for Maya that generated the output fi le, and one viewer application capable of rendering the resulting mesh. The geometry output of the proposed technique was evaluated by comparing it to uniformly tessellated reference mesh geometry. Measurements show that the proposed technique is capable of reducing the face count with minor or maintained correlation to the reference geometry. / Medans spelindustrin växer ökar behovet av visuellt tilltalande grafik. Detta driver utvecklingen av hårdvara och nya tekniker framåt. Med den senaste generationens 3D grafik API kom renderingssteget tesselering. Eftersom varje generation av spel blir mer avancerat ökar efterfrågan på detaljerade modeller. Detta leder till en högre arbetsbörda för GPUn. Syftet med denna avhandling är att undersöka tesselering och utveckla en prototyp för att optimera tesseleringspipelinen. Prototypen är utformad för att hjälpa till att minska antalet genererade trianglar genom att dela upp figuren i regioner, varje region med egen tesseleringsfaktor. Prototypen stödjer både manuell och automatisk generering av dessa regioner, ett nytt filformat utvecklades för att stödja dessa. Prototypen delades upp i tre delar, ett Python baserat Maya plug-in som används för att förbereda modellen för export, en Maya exportör som genererar filerna, och ett visningsprogram som kan rendera den färdiga figuren. Figuren från den föreslagna tekniken utvärderades genom att jämföra den med motsvarande figur med universal tesseleringsfaktor. Mätningar visar att den föreslagna tekniken klarar att reducera antalet trianglar med låg felmarginal.
482

Vector Displacement Mapping

Lundström, Emrik January 2014 (has links)
Kontext: Displacement Mapping är en teknik som används inom 3D-spel för att skapa detaljrikedom i geometri utan att behöva triangelobjekt bestående av oönskad geometrikomplexitet. Tekniken har även andra användningsområden i 3D-spel, till exempel terränggeometri. Tekniken skänker detaljrikedom genom att i samband med tesselering förskjuta geometri i en normalriktning eller längs annan specificerad riktning. Vector Displacement Mapping är en teknik liknande Displacement Mapping där skillnaden är att Vector Displacement Mapping förskjuter geometri i tre dimensioner. Mål: Syftet med arbetet är utforska Vector Displacement Mapping i sammanhanget 3D-Spel och att antyda att tekniken kan användas i 3D-spel likt Displacement Mapping. Arbetet jämför Vector Displacement Mapping med Displacement Mapping för att urskilja skillnader i exekveringstid mellan teknikernas centrala skillnader. Skillnaderna i exekveringstid ställs i kontrast mot diskussion av teknikernas grafikminnesanvändning. Metoder: Jämförelsen baseras på en implementation av de båda teknikerna tillsammans med tesselering. Prestandamätningar genereras med implementationen som grund. Implementationen använder sig av Direct3D 11. Resultat: Resultatet som erhålls genom jämförelsen visar att exekveringstiderna mellan teknikernas centrala skillnader varierar svagt. Grafikminnesanvändningen mellan teknikerna skiljer sig med en faktor 3 eller en faktor 4 där Vector Displacement Mapping använder mer grafikminne. Slutsatser: Slutsatser som dras baserat på resultatet är att Vector Displacement Mapping i situationer där överhängande geometri är ett önskat resultat kan ersätta Displacement Mapping. Vidare diskussion förs kring slutsatser, avgränsningar och framtida forskning som arbetet berör.
483

Evaluación estructural y ampliación de niveles para el cambio de uso de la casa del adulto mayor a centro comercial en el Distrito de La Molina

Mallaupoma Arias, Brayhan Ubaldo, Montenegro Callacna, Omar Kenny January 2015 (has links)
En la evaluación estructural y ampliación de niveles para el cambio de uso de la casa del adulto mayor a centro comercial en el distrito de la molina, se determina que tan factible puede ser darle un uso comercial a una casa del adulto mayor que con las modificaciones necesarias a nivel de estructura como la ampliación de la misma en 3 niveles, nos brinda un negocio potencialmente rentable, gracias a la zona comercial donde se encuentra ubicada avenida alameda del corregidor – Cuadra 5 y el área aproximada de 700m2. Por ello ,tenemos como objetivo general evaluar la estructura de una casa del adulto mayor para el cambio de uso a centro comercial en el distrito de La Molina y como consecuencia a la evaluación determinar si es factible ampliarlo en 3 niveles más con el fin de darle un mejor uso, acondicionándola como tiendas comerciales en todos sus niveles. La principal teoría utilizada para evaluar la estructura y ampliarla son el análisis sísmico estático y dinámico teniendo en cuenta las cargas puntuales y distribuidas de la estructura para el estático y el espectro de Pseudo-aceleraciones para el dinámico de acuerdo a la normatividad vigente, también el modelamiento estructural en el programa ETABS con el que mediante el análisis del programa nos proporcionara los desplazamiento en la estructura y con estos resultados de acuerdo a la norma sísmica vigente podremos determinar las distorsiones en cada nivel siendo estos valores para que cumpla con la norma menores a 0.07. El tipo de investigación utilizado es básico, cuantitativo, explicativo y el diseño es no experimental, transversal y descriptivo. Es prospectiva pues trata de un diseño sísmico donde trabajaremos con valores proporcionados por el programa. De los resultados que se calcularon tanto en la estructura original como en la ampliación se determinó que el cambio de uso para la estructura original teniendo en cuenta el retiro de las cargas adicionales y la ampliación es factible ya que ningún valor en las torsiones fueron mayores al 0.07 propuesto en la norma. In the structural evaluation and extension levels for the change of use of the house of the elderly to shopping center in the district of La Molina, it is determined to be feasible as a commercial use to give a house the elderly with amendments necessary level of structure and expanding the same into 3 levels, it offers a potentially profitable business, thanks to the commercial area where it is located mayor Avenue Mall - Cuadra 5 to the approximate area of 700m2. Therefore, we have as a general objective to evaluate the structure of a house of the elderly for change of use to a commercial center in the district of La Molina and consequently to determine the feasibility assessment extend over 3 levels more in order to give better use, renovating as commercial shops at all levels. The main theory used to evaluate the structure and expand are static and dynamic seismic analysis considering point loads and distributed structure for static and pseudo-acceleration spectrum for dynamic according to regulations, also the structural modeling in ETABS program that by analyzing the program we provide the shift in the structure and the results according to current seismic code can determine distortions at each level being these values to comply with the norm under 0.07. The research used is basic, quantitative and explanatory design is not experimental, transversal and descriptive. It is a prospective for seismic design where work with values provided by the program. From the results that were calculated in both the original structure and the extension was determined that change of use for the original structure considering the withdrawal of additional charges and the expansion it is feasible because no value was higher by twisting 0.07 proposed in the standard.
484

Performance aspects of layered displacement blending in real time applications

Petersson, Tommy, Lindeberg, Marcus January 2013 (has links)
The purpose of this thesis is to investigate performance aspects of layered displacement blending; a technique used to render realistic and transformable objects in real time rendering systems using the GPU. Layered displacement blending is done by blending layers of color maps and displacement maps together based on values stored in an influence map. In this thesis we construct a theoretical and practical model for layered displacement blending. The model is implemented in a test bed application to enable measuring of performance aspects. The implementation is fed input with variations in triangle count, number of subdivisions, texture size and number of layers. The execution time for these different combinations are recorded and analyzed. The recorded execution times reveal that the amount of layers associated with an object has no impact on performance. Further analysis reveals that layered displacement blending is heavily dependent on the triangle count in the input mesh. The results show that layered displacement blending is a viable option to representing transformable objects in real time applications with respect to performance. This thesis provides; a theoretical model for layered displacement blending, an implementation of the model using the GPU and measurements of that implementation.
485

Paleoenvironment and shore displacement since 3200 BC in the central part of the  Långhundraleden Trail, SE Uppland

Katrantsiotis, Christos January 2013 (has links)
In this study, litho-, bio- and chronostratigraphic investigations combined with RTK GPSleveling have been carried out to reconstruct the paleoenvironment in the central part of theLånghundraleden Trail. The area displays four shallow lake basins of varyingmorphologies. The basins are now covered with peat as a result of infilling and overgrowth.The emergence of the saddle-point, i.e. the highest point of the underlying minerogenicsurface, was estimated to have occurred c. BC/AD. The isolation events of two basins, atc.12.4 and c.12.3 m a.s.l. west and east of the saddle-point, were dated to c.AD 20 andc.AD 30, respectively. By combining these isolation data with six previously investigatedbasins a shore displacement curve for the central part of the Långhundraleden Trail and thesurrounding area, i.e. east of the Ekoln basin was constructed. The curve indicates anaverage regressive shore displacement rate of c.6.2 mm/yr since c. 3200 BC. Around 1500BC, this trend was interrupted by a short period of retarded regression, correlated with theL4 event. The isolation ages of the basins in the Långhundraleden Trail appears relativelyyoung when compared to an average shore displacement rate of 5.6 mm/year in thenorthern part of L. Mälaren, west of the Ekoln basin. As the area is dominated by a fissurevalleylandscape, this discrepancy could be attributed to small-scale irregular tectonicmovements, which caused faster uplift rate, i.e. 6.2 mm/year, east of the Ekoln basin.
486

VALIDATION, OPTIMIZATION, AND IMAGE PROCESSING OF SPIRAL CINE DENSE MAGNETIC RESONANCE IMAGING FOR THE QUANTIFICATION OF LEFT AND RIGHT VENTRICULAR MECHANICS

Wehner, Gregory J. 01 January 2017 (has links)
Recent evidence suggests that cardiac mechanics (e.g. cardiac strains) are better measures of heart function compared to common clinical metrics like ejection fraction. However, commonly-used parameters of cardiac mechanics remain limited to just a few measurements averaged over the whole left ventricle. We hypothesized that recent advances in cardiac magnetic resonance imaging (MRI) could be extended to provide measures of cardiac mechanics throughout the left and right ventricles (LV and RV, respectively). Displacement Encoding with Stimulated Echoes (DENSE) is a cardiac MRI technique that has been validated for measuring LV mechanics at a magnetic field strength of 1.5 T but not at higher field strengths such as 3.0 T. However, it is desirable to perform DENSE at 3.0 T, which would yield a better signal to noise ratio for imaging the thin RV wall. Results in Chapter 2 support the hypothesis that DENSE has similar accuracy at 1.5 and 3.0 T. Compared to standard, clinical cardiac MRI, DENSE requires more expertise to perform and is not as widely used. If accurate mechanics could be measured from standard MRI, the need for DENSE would be reduced. However, results from Chapter 3 support the hypothesis that measured cardiac mechanics from standard MRI do not agree with, and thus cannot be used in place of, measurements from DENSE. Imaging the thin RV wall with its complex contraction pattern requires both three-dimensional (3D) measures of myocardial motion and higher resolution imaging. Results from Chapter 4 support the hypothesis that a lower displacement-encoding frequency can be used to allow for easier processing of 3D DENSE images. Results from Chapter 5 support the hypothesis that images with higher resolution (decreased blurring) can be achieved by using more spiral interleaves during the DENSE image acquisition. Finally, processing DENSE images to yield measures of cardiac mechanics in the LV is relatively simple due to the LV’s mostly cylindrical geometry. Results from Chapter 6 support the hypothesis that a local coordinate system can be adapted to the geometry of the RV to quantify mechanics in an equivalent manner as the LV. In summary, cardiac mechanics can now be quantified throughout the left and right ventricles using DENSE cardiac MRI.
487

Assessing uplift displacement of buried geotechnical structures in liquefied ground during earthquakes / 液状化地盤中における埋設構造物の浮き上がり量の評価に関する研究

Kang, GiChun 23 March 2010 (has links)
Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(工学) / 甲第15340号 / 工博第3219号 / 新制||工||1485(附属図書館) / 27818 / 京都大学大学院工学研究科社会基盤工学専攻 / (主査)教授 井合 進, 教授 岡 二三生, 教授 木村 亮 / 学位規則第4条第1項該当
488

Fast searching measurement of absolute displacement based on submicron-aperture fiber point-diffraction interferometer

Wang, Daodang, Wang, Zhichao, Liang, Rongguang, Kong, Ming, Zhao, Jun, Zhao, Jufeng, Mo, Linhai, Li, Wei 26 June 2017 (has links)
The submicron-aperture fiber point-diffraction interferometer (SFPDI) can be applied to realize the measurement of three-dimensional absolute displacement within large range, in which the performance of point-diffraction wavefront and numerical iterative algorithm for displacement reconstruction determines the achievable measurement accuracy, reliability and efficiency of the system. A method based on fast searching particle swarm optimization (FS-PSO) algorithm is proposed to realize the rapid measurement of three-dimensional absolute displacement. Based on the SFPDI with two submicron-aperture fiber pairs, FS-PSO method and the corresponding model of the SFPDI, the measurement accuracy, reliability and efficiency of the SFPDI system are significantly improved, making it more feasible for practical application. The effect of point-diffraction wavefront error on the measurement is analyzed. The error of point-diffraction wavefront obtained in the experiment is in the order of 1x10(-4). (the wavelength. is 532 nm), and the corresponding displacement measurement error is smaller than 0.03 mu m. Both the numerical simulation and comparison experiments have been carried out to demonstrate the accuracy and feasibility of the proposed SFPDI system, high measurement accuracy in the order of 0.1 mu m, convergence rate (similar to 90.0%) and efficiency have been realized with the proposed method, providing a feasible way to measure three-dimensional absolute displacement in the case of no guide rail.
489

Value of animal traceability systems in managing a foot-and-mouth disease outbreak in southwest Kansas

Pendell, Dustin Lester January 1900 (has links)
Doctor of Philosophy / Department of Agricultural Economics / Ted C. Schroeder / Concerns regarding management of animal disease and related perceptions about food safety have escalated substantially in recent years. Terrorist attacks of September 2001, discovery of bovine spongiform encephalopathy in a dairy cow in December 2003 in Washington state and subsequent discoveries of BSE infected animals in Texas in 2005 and Alabama in 2006, and recent worldwide outbreaks of highly contagious animal diseases (i.e., Foot-and-Mouth Disease and Avian Influenza A (H5N1)) have made apparent the need for animal traceability in U.S. livestock production and marketing. In addition, animal identification and trace-back systems are rapidly developing throughout the world increasing international trading standards. In recent years, increasing numbers of economic analyses of animal diseases have integrated epidemiological models into economic frameworks. However, there are only a few studies that have used this integrated framework to analyze the effects of animal traceability on highly contagious animal diseases. This study’s goal is to quantify and evaluate the economic impacts of different depths of animal identification/trace-back systems in the event of a hypothetical highly contagious foot-and-mouth disease outbreak that poses a threat to U.S. livestock competitiveness. Specifically, an epidemiological disease spread model is used to evaluate the impact of a foot-and-mouth disease outbreak in southwest Kansas. The information obtained from the disease spread model is then used in conjunction with an economic model to determine the changes in welfare of producers and consumers. Results obtained from the epidemiological model indicate that as the depth of animal identification in cattle is increased, the number of animals destroyed is reduced as are the associated costs. Also, the length of the outbreak is reduced by approximately two weeks. The economic results suggest that as surveillance is increased, decreases in producer and consumer welfare are smaller. Furthermore, as surveillance is increased, decreases in producer and consumer surplus measures can be reduced by approximately 60 percent.
490

Modeling of nailed timber connection : Displacement path dependency in sheathing-to-framing connections

Mmari, Winston January 2017 (has links)
Connections in wood have been investigated and advanced ever since the ground-breaking work of Johansen in the early nineteenth century. Nevertheless, not much investigation has been undertaken on the existence of load-displacement path dependency in a sheathing-to-framing connection. Herein, a sheathing-to-framing connection is investigated in relation to displacement path dependency. This work uses 3D Finite Element beam-on-foundation models of an Oriented Strand Board (OSB/2) sheathing nailed to a C24 wood framing, to study possible strategies to numerically simulate the displacement path dependency. The models are used to study if non-linear elastic or elastic-plastic embedment properties of an annular-ringed shank nail in the wood-based materials bring about the path dependency using Connector elements in combination with different material models in the FE software Abaqus. Numerical results are compared with corresponding experimental test results of the connection together with the Eurocode 5 approach. The outcome of the numerical study both; confirms the existence of displacement path dependency and shows that this property in the connection can be described by plasticity properties in nail, sheathing material and the wood framing.

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