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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.
81

Biomechanical investigations of bend running technique in athletic sprint events

Churchill, Sarah January 2012 (has links)
For sprint events longer than 100 m, more than half the race is run on the bend, yet bend sprinting has received little attention in biomechanics literature. The aim of this thesis was to understand the effect of the bend on maximal effort sprint performance and technique, using bend radii and surfaces typical of outdoor competition. Three empirical studies were undertaken with experienced bend sprinters. Initial 3D kinematics investigations revealed an approximately 5% velocity decrease on the bend compared to the straight. However, step characteristic changes contributing to this reduction were different for the left and right steps. For the left step there were significant decreases in step frequency (p < 0.05), due to increased ground contact time, which agreed with previously proposed theoretical models. For the right step, however, a significantly reduced flight time resulted in a significant reduction in step length (p < 0.05). Maintaining step length and an ‘active touchdown’ were closely related to an athlete’s ability to better maintain straight line velocity on the bend. Generally, velocity decreased as bend radius decreased, with mean differences of up to 2.3% between lanes 8 and 2. However, changes to athletes’ technique due to different lanes were not conclusive. Ground reaction forces revealed between-limb differences during bend sprinting. Furthermore, frontal plane forces were up to 2.6 times larger on the bend than on the straight. Overall, asymmetries were identified between left and right steps for several performance, technique and force variables, suggesting that bend sprinting induces different functional roles between left and right legs, with the left step contributing more to turning to remain on the bend trajectory. The differences in kinematic and kinetic characteristics between the bend and straight, and between-limb asymmetries mean that athletes should apply the principle of specificity to bend sprinting training and conditioning, without sacrificing straight line technique.
82

Harmonious Storm

DOU, JIAYUN January 2011 (has links)
The intention with this imaginary storm in the form of a decorative lamp ‘Harmonious Storm’ is meant to hang from the ceiling, sculptural and often glowing with artificial light. Meanwhile it enhances the attractive value in the specific public space. The relation between importance of aesthetics and interior public environment is discussed in this thesis, with a purpose of achieving emotional and social needs that are excitement and happiness. / Program: Konstnärligt masterprogram i mode- och textildesign
83

Three-dimensional reconstruction outside of the laboratory

Bennett, Stuart Charles January 2014 (has links)
No description available.
84

Intuitive freeform modeling using subdivision surfaces.

January 2005 (has links)
Lai Yuen-hoo. / Thesis submitted in: November 2004. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 100-102). / Abstracts in English and Chinese. / Abstract --- p.i / 摘要 --- p.ii / Acknowledgment --- p.iii / List of Figures --- p.iv / Table of Content --- p.vii / Chapter 1. --- Introduction --- p.1 / Chapter 1.1. --- Problem Definition --- p.1 / Chapter 1.2. --- Proposed Solution --- p.2 / Chapter 1.3. --- Thesis Contributions --- p.2 / Chapter 2. --- Modeling Approaches --- p.4 / Chapter 2.1. --- Polygon Modeling --- p.4 / Chapter 2.2. --- Patch Modeling --- p.6 / Chapter 2.3. --- Freehand Sketch-based Modeling --- p.7 / Chapter 2.4. --- Template Based Modeling --- p.8 / Chapter 2.5. --- Curve Interpolation Method --- p.9 / Chapter 3. --- Surface Operations --- p.11 / Chapter 3.1. --- Surface Blending --- p.11 / Chapter 3.2. --- Surface Trimming --- p.13 / Chapter 3.3. --- Boolean Operations --- p.14 / Chapter 4. --- Subdivision Surface --- p.16 / Chapter 4.1. --- Basic Principle --- p.16 / Chapter 4.2. --- Catmull-Clark Surface --- p.17 / Chapter 5. --- Modeling Algorithm Overview --- p.21 / Chapter 6. --- Subdivision Surface Generation --- p.23 / Chapter 6.1. --- Input Curves --- p.23 / Chapter 6.2. --- Surface Sweeping --- p.24 / Chapter 6.3. --- Subdivision Surface Fitting --- p.29 / Chapter 7. --- Surface Blending --- p.32 / Chapter 7.1. --- Introduction --- p.32 / Chapter 7.2. --- Problem Definition --- p.32 / Chapter 7.3. --- Algorithm Overview --- p.36 / Chapter 7.4. --- Blend Region Detection --- p.39 / Chapter 7.4.1. --- Collision Detection --- p.40 / Chapter 7.4.2. --- Result and Analysis --- p.42 / Chapter 7.5. --- "Mesh Refinement, Surface Fitting and Region Removal" --- p.46 / Chapter 7.5.1. --- Mesh Refinement --- p.46 / Chapter 7.5.1.1. --- Adaptive Subdivision --- p.46 / Chapter 7.5.1.2. --- Additional Subdivision Constraint --- p.47 / Chapter 7.5.2. --- Surface Fitting --- p.49 / Chapter 7.5.2.1. --- General Approach --- p.49 / Chapter 7.5.2.2. --- Surface Point Correspondence --- p.50 / Chapter 7.5.2.3. --- Numerical Fitting Method --- p.51 / Chapter 7.5.3. --- Unwanted Region Removal --- p.55 / Chapter 7.5.4. --- Result and Analysis --- p.56 / Chapter 7.6. --- Boundary Smoothing --- p.58 / Chapter 7.6.1. --- General Approach --- p.59 / Chapter 7.6.2. --- Constraint on Deformation Direction of Vertex --- p.61 / Chapter 7.6.3. --- Result and Analysis --- p.63 / Chapter 7.7. --- Blend Curves --- p.65 / Chapter 7.7.1. --- Problem Definition --- p.65 / Chapter 7.7.2. --- Proposed Solution Overview --- p.66 / Chapter 7.7.3. --- Maintenance of Regular Vertex Valence along Blend Curve --- p.67 / Chapter 7.7.3.1. --- Pairing Up Blend Boundary Vertices --- p.70 / Chapter 7.7.4. --- Minimization of Distortion Caused by Extraordinary Vertices --- p.72 / Chapter 7.7.5. --- Blend Vertex Position Optimization Function --- p.74 / Chapter 7.7.5.1. --- Face Normal Expression --- p.74 / Chapter 7.7.5.2. --- Face Normal Difference Energy Function --- p.77 / Chapter 7.7.5.3. --- Midpoint Distance Energy Function --- p.78 / Chapter 7.7.5.4. --- Weighted Least Square Energy Minimization --- p.78 / Chapter 8. --- Implementation --- p.81 / Chapter 8.1. --- Data Structure --- p.81 / Chapter 8.2. --- User Interface --- p.82 / Chapter 9. --- Results --- p.83 / Chapter 9.1. --- Surface Generation --- p.83 / Chapter 9.2. --- Surface Blending --- p.86 / Chapter 9.2.1. --- Ideal Case --- p.86 / Chapter 9.2.2. --- Angle of Insertion --- p.87 / Chapter 9.2.3. --- Surface Feature Near Intersection --- p.88 / Chapter 9.2.4. --- Comparison --- p.89 / Chapter 9.2.5. --- Other Examples --- p.92 / Chapter 9.3. --- Overall Performance --- p.94 / Chapter 9.4. --- Limitations --- p.97 / Chapter 9.4.1. --- Limitation on Generated Shape --- p.97 / Chapter 9.4.2. --- Limitation on Input Surfaces --- p.98 / Chapter 10. --- Conclusion and Future Work --- p.99 / References --- p.100
85

An Automated System for Design and Analysis of Total Hip Implants: A Method of Modeling the Proximal Endosteal Canal Using 3-D CT Data

Manasas, Mark A. 01 April 1999 (has links)
The clinical success of Total Hip Arthroplasty is enhanced by matching hip implant geometry to femoral geometry. Traditionally, the shapes of hip implant designs have been based on data collected from patient populations using X-ray, CT Scan, digitized sliced bone, and other physical methods. The morphology of interest and the frame of reference often vary across researchers and the resulting numeric data are difficult to use in a Computer Aided Design package to build an implant model. This goal of this thesis was to develop procedures and automated programs for the design and evaluation of femoral hip implants using CT data. The procedures bridge the gap between patient specific "custom" prosthesis design and the so-called "averaged femur" implant designs. By automating the measurement, orientation and averaging of any user selected grouping of femora, these programs allow construction of an average femur template for small subsets of a population or populations. The programs allow grouping of femora using either dimensional attributes and/or patient attributes such as pathology, ethnic background, etc. The average femur template created for each group can then be used as the design boundary for a discrete implant size. Additional functionality is also provided for comparing average femur templates to their constitutive femora and for comparison of average femur templates against each other. To illustrate that the goals of this theses were realized, an example of the use of the system for a population of 192 Japanese is included in this thesis. The criteria for evaluation of the average femur templates was the gap or interference of the template to that of each constitutive femur along the medial and lateral endosteal contours. Testing 24 template sizes, the average of the worst fitting template to femur combination for each size resulted in a gap or interference of less than 2mm in the metaphysis and less than 4mm proximally.
86

3D metric reconstruction from uncalibrated circular motion image sequences

Zhong, Huang. January 2006 (has links)
Thesis (Ph. D.)--University of Hong Kong, 2006. / Title proper from title frame. Also available in printed format.
87

3D reconstruction of road vehicles based on textural features from a single image

Lam, Wai-leung, William. January 2006 (has links)
Thesis (Ph. D.)--University of Hong Kong, 2006. / Title proper from title frame. Also available in printed format.
88

Hybrid computational voxelization using the graphics pipeline

Rauwendaal, Randall 29 November 2012 (has links)
This thesis presents an efficient computational voxelization approach that utilizes the graphics pipeline. Our approach is hybrid in that it performs a precise gap-free computational voxelization, employs fixed-function components of the GPU, and utilizes the stages of the graphics pipeline to improve parallelism. This approach makes use of the latest features of OpenGL and fully supports both conservative and thin voxelization. In contrast to other computational voxelization approaches, this approach is implemented entirely in OpenGL, and achieves both triangle and fragment parallelism through its use of both the geometry and fragment shaders. A novel approach utilizing the graphics pipeline to complement geometric triangle intersection computations is presented. By exploiting features of the existing graphics pipeline we are able to rapidly compute accurate scene voxelization in a manner that integrates well with existing OpenGL applications, is robust across many different models, and eschews the need for complex work/load-balancing schemes. / Graduation date: 2013
89

Improvement of the camera calibration through the use of machine learning techniques

Nichols, Scott A., January 2001 (has links) (PDF)
Thesis (M.S.)--University of Florida, 2001. / Title from first page of PDF file. Document formatted into pages; contains vii, 45 p.; also contains graphics. Vita. Includes bibliographical references (p. 43-44).
90

3D reconstruction and camera calibration from circular-motion image sequences

Li, Yan, January 2005 (has links)
Thesis (Ph. D.)--University of Hong Kong, 2006. / Title proper from title frame. Also available in printed format.

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