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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.
351

Assessment of flood mitigation strategies for the city of Kalona, Ia

Koser, David Ryan 01 December 2015 (has links)
In order to reduce flooding, communities often try to control runoff with a storm sewer network, detention basins, low impact developments, and upstream storage to reduce stream overflow. Numerical models can help predict the effect these strategies will have before expensive construction projects are underway. A coupled 1D/2D hydraulic model using XPSWMM was created for the town of Kalona, IA, to test different strategies for flood reduction. XPSWMM utilizes one dimensional and two dimensional St. Venant equations to model flow in streams and pipes, or overland flow on the surface, respectively. The town of Kalona, upstream highlands, and the downstream floodplains were modeled utilizing a 4 meter cell-size unstructured grid. The model was neither calibrated nor validated, but its performance was comparable to a previously built MIKE 11/21 model of the same area when given the same inputs. The city drains into Salvesen Creek, the Central Drainage Ditch, and the East Drainage Ditch, with Salvesen Creek having the largest drainage area. 14 agricultural detention ponds upstream of the town were modeled to determine their effectiveness in reducing stream overflow, while modifications to the storm sewer network and in situ detention provided relief from local runoff. The detention ponds and modifications were modeled both separately and together and compared to a base model using the 10 year, 25 year, 50 year, 100 year, and 500 year, 3 hour storms. The different methods were compared using three index points: City Hall, Pleasant View Circle, and in a softball practice area. The upstream agricultural detention ponds provided a peak reduction of 2%, 13%, and 9%, respectively, while the in situ modifications reduced flooding by 0%, 44%, and 18%, respectively, for the 10 year storm. The combined techniques reduced flooding by 2%, 44%, and 20%, respectively. During the 100 year storm, the detention ponds, modifications, and combined techniques reduced peak flood depths by 17%, 24%, and 14%; 2%, 3%, and 22%; and 17%, 55%, and 23%, respectively. This demonstrated that the in situ modifications were more effective during low flood events while ponds were more effective at high flood events. The combined approach was most effective when the two methods complemented each other. Future work might determine areas throughout the town where reduced flow and in situ modifications together would be most effective and design approaches to maximize flood reduction. Additional features to be modeled include pumps to increase capacity in the storm sewer network, levees, and supplementary drainage channels.
352

Study of the Motility of Biological Cells by Digital Holographic Microscopy

Yu, Xiao 01 May 2014 (has links)
In this dissertation, I utilize digital holographic microscopy (DHM) to study the motility of biological cells. As an important feature of DHM, quantitative phase microscopy by digital holography (DH-QPM) is applied to study the cell-substrate interactions and migratory behavior of adhesive cells. The traction force exerted by biological cells is visualized as distortions in flexible substrata. Motile fibroblasts produce wrinkles when attached to a silicone rubber film. For the non-wrinkling elastic substrate polyacrylamide (PAA), surface deformation due to fibroblast adhesion and motility is visualized as tangential and vertical displacement. This surface deformation and the associated cellular traction forces are measured from phase profiles based on the degree of distortion. Intracellular fluctuations in amoeba cells are also analyzed statistically by DH-QPM. With the capacity of yielding quantitative measures directly, DH-QPM provides efficient and versatile means for quantitative analysis of cellular or intracellular motility. Three-dimensional profiling and tracking by DHM enable label-free and quantitative analysis of the characteristics and dynamic processes of objects, since DHM can record real-time data for micro-scale objects and produce a single hologram containing all the information about their three-dimensional structure. Here, I utilize DHM to visualize suspended microspheres and microfibers in three dimensions, and record the four-dimensional trajectories of free-swimming cells in the absence of mechanical focus adjustment. The displacement of microfibers due to interactions with cells in three spatial dimensions is measured as a function of time at sub-second and micrometer levels in a direct and straightforward manner. It has thus been shown that DHM is a highly efficient and versatile means for quantitative tracking and analysis of cell motility.
353

1D and 2D Methods for Modeling Floodplains under Storm Surge Conditions

January 2011 (has links)
This study evaluates a 1D and a 2D method for analyzing the combined effect of inland rainfall and hurricane-induced storm surge on a coastal floodplain. Horsepen Bayou near Clear Lake, southeast of Houston, Texas is vulnerable to storm surge, which can travel upstream into the Bayou and exacerbate flooding outside the designated floodplain. However, the current 100-year floodplain for this area is delineated using a 1D model without direct storm surge inputs. Additionally, floodplains with flat topography, like Horsepen, could be modeled more accurately using 2D models, instead of the traditional 1D approach. A 1D HEC-RAS model and a 2D XPSWMM model are used to compare the resulting floodplain from three historical storms and one synthetic storm. When compared to actual FEMA flood claims, the floodplains calculated by the 2D model are more representative of inundation hazard in Horsepen and therefore a better tool for evaluating flooding in the area.
354

Using two- and three-dimensional kinematic analysis to compare functional outcomes in patients who have undergone facial reanimation surgery

Dunwald, Lisa Unknown Date
No description available.
355

Three Dimensional Hyperbolic Grid Generation

Dincgez, Umut Can 01 April 2006 (has links) (PDF)
This thesis analyzes procedure of generation of hyperbolic grids formulated by two constraints, which specify grid orthogonality and cell volume. The procedure was applied on a wide range of geometries and high quality two and three dimensional hyperbolic grids were generated by using grid control and smoothing procedures, which supply grid clustering in all directions and prevent grid deformation (grid shock), respectively.
356

Using two- and three-dimensional kinematic analysis to compare functional outcomes in patients who have undergone facial reanimation surgery

Dunwald, Lisa 11 1900 (has links)
The current study was designed to: (1) compare the sensitivity of a 2-dimensional video-based system with a 3-dimensional optical system, and (2) investigate movement on the affected and unaffected side of the face during the production of various functional movement tasks in 5 patients who had undergone facial reanimation surgery. The study showed that: (1) distance is the most valuable measure for evaluating facial paralysis, regardless of system; (2) movements associated with maximal contraction and running speech tasks are most informative when assessing facial paralysis; (3) area and volume ratios may be an appropriate measure for tracking changes in facial movement over time; (4) velocity and acceleration measures provide minimal information regarding facial movement; and (5) 2-dimensional analysis is most effective when distance is measured during maximal contraction and running speech tasks. Both systems were effective in tracking small movements of the face, but the 3-dimensional system was superior overall.
357

A correspondence framework for surface matching algorithms

Planitz, Brigit Maria January 2004 (has links)
Computer vision tasks such as three dimensional (3D) registration, 3D modelling, and 3D object recognition are becoming more and more useful in industry, and have application such as reverse CAD engineering, and robot navigation. Each of these applications use correspondence algorithms as part of their processes. Correspondence algorithms are required to compute accurate mappings between artificial surfaces that represent actual objects or scenes. In industry, inaccurate correspondence is related to factors such as expenses in time and labour, and also safety. Therefore, it is essential to select an appropriate correspondence algorithm for a given surface matching task. However, current research in the area of surface correspondence is hampered by an abundance of applications specific algorithms, and no uniform terminology of consistent model for selecting and/or comparing algorithms. This dissertation presents a correspondence framework for surface matching algorithms. The framework is a conceptual model that is implementable. It is designed to assist in the analysis, comparison, development, and implementation of correspondence algorithms, which are essential tasks when selecting or creating an algorithm for a particular application. The primary contribution of the thesis is the correspondence framework presented as a conceptual model for surface matching algorithms. The model provides a systematic method for analysing, comparing, and developing algorithms. The dissertation demonstrates that by dividing correspondence computation into five stages: region definition, feature extraction, feature representation, local matching, and global matching, the task becomes smaller and more manageable. It also shows that the same stages of different algorithms are directly comparable. Furthermore, novel algorithms can be created by simply connecting compatible stages of different algorithms. Finally, new ideas can be synthesised by creating only the stages to be tested, without developing a while new correspondence algorithm. The secondary contribution that is outlined is the correspondence framework presented as a software design tool for surface matching algorithms. The framework is shown to reduce the complexity of implementing existing algorithms within the framework. This is done by encoding algorithms in a stage-wise procedure, whereby an algorithm is separated into the five stages of the framework. The software design tool is shown to validate the integrity of restructuring existing algorithms within it, and also provide an efficient basis for creating new algorithms. The third contribution that is made is the specification of a quality metric for algorithms comparison. The metric is used to assess the accuracy of the outcomes of a number of correspondence algorithms, which are used to match a wide variety of input surface pairs. The metric is used to demonstrate that each algorithm is application specific, and highlight the types of surfaces that can be matched by each algorithm. Thus, it is shown that algorithms that are implemented within the framework can be selected for particular surface correspondence tasks. The final contribution made is this dissertation is the expansion of the correspondence framework beyond the surface matching domain. The correspondence framework is maintained in its original form, and is used for image matching algorithms. Existing algorithms from three image matching applications are implemented and modified using the framework. It is shown how the framework provides a consistent means and uniform terminology for developing both surface and image matching algorithms. In summary, this thesis presents a correspondence framework for surface matching algorithms. The framework is general, encompassing a comprehensive set of algorithms, and flexible, expanding beyond surface matching to major image matching applications.
358

Efficient and reliable methods for direct parameterized image registration

Brooks, Rupert. January 1900 (has links)
Thesis (Ph.D.). / Written for the Dept. of Electrical & Computer Engineering. Title from title page of PDF (viewed 2008/01/12). Includes bibliographical references.
359

Longitudinal analysis of three-dimensional facial shape data

Barry, Sarah Jane Elizabeth. January 2008 (has links)
Thesis (Ph.D.) - University of Glasgow, 2008. / Ph.D. thesis submitted to the Faculty of Information and Mathematical Sciences, Department of Statistics, University of Glasgow, 2008. Includes bibliographical references. Print version also available.
360

Determintaion of three-dimensional information by use of a three-dimensional/two-dimensional matching technique /

Esthappan, Jacqueline. January 2000 (has links)
Thesis (Ph. D.)--University of Chicago, Dept. of Radiology, August 2000. / Includes bibliographical references. Also available on the Internet.

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