The ability to create large-scale high-resolution models of biological tissue provides an excellent opportunity for expanding our understanding of tissue structure and function. This is particularly important for brain tissue, where the majority of function occurs at the cellular and sub-cellular level. However, reconstructing tissue at sub-cellular resolution is a complex problem that requires new methods for imaging and data analysis. In this dissertation, I describe a prototype microscopy technique that can image large volumes of tissue at sub-cellular resolution. This method, known as Knife-Edge Scanning Microscopy (KESM), has an extremely high data rate and can capture large tissue samples in a reasonable time frame. We can therefore image complete systems of cells, such as whole small animal organs, in a matter of days. I then describe algorithms that I have developed to cope with large and complex data sets. These include methods for improving image quality, tracing filament networks, and constructing high-resolution anatomical models. These methods are highly parallel and designed to allow users to segment and visualize structures that are unique to high-throughput microscopy data. The resulting models of large-scale tissue structure provide much more detail than those created using standard imaging and segmentation techniques.

A laboratory experiment was performed to investigate the three-dimensional turbulence and kinematic properties that develop due to a breaking solitary and an irregular shallow water bathymetry. A large basin equipped with a piston-type wavemaker was used to generate the wave, while the free surface elevations and fluid velocities were measured using wave gauges and three-dimensional acoustic-Doppler velocimeters (ADVs), respectively. From the free surface elevations, the evolution and runup of the wave was revealed; while from the ADVs, the velocity and turbulent energy was determined to identify specific turbulent events and coherent structures. It was found that shoaling was confined to areas with gentler sloping bathymetry near the basin side walls and the runup shoreward of the still water shoreline was not uniform. The runup was characterized by a jetting mechanism caused by the convergence of water mass near the basin centerline as the wave refracted during breaking. The jetting mechanism caused the greatest cross-shore velocities to be located near the basin centerline. The greatest turbulent events were well correlated to borefronts, resembling hydraulic jumps, where the greatest shear and fluid accelerations occurred. Because of an abrupt change in the bathymetry, a coherent structure developed which was found to have a three-dimensional flow field. It was proposed that variations in the internal flow with depth were due to the orientation of multiple vortex rings.

Perennial ryegrass (Lolium perenne L.) is commonly overseeded into hybrid bermudagrass [Cynodon dactylon (L.) Pers. X C. transvaalensis Burtt Davy] turfs during autumn in the southern United States. Overseeding can provide a green, actively-growing turf throughout the winter dormancy period. Improved persistence of perennial ryegrass cultivars has increased management inputs during the spring transition period. Lower input turf systems that provide acceptable winter overseeding quality are preferred, and research aimed at evaluating alternative overseeding species are warranted. Grooming reel attachments allowing for threedimensional clipping management (3DCM) have become increasingly used by turf managers for reducing grain and thatch, but scientific information on best management practices and canopy effects of 3DCM-grooming are lacking. A field study was conducted at the Texas A&M Turfgrass Field Laboratory in College Station, TX (30.6191 degrees N, 96.3576 degrees W), to investigate the effects of overseeding using annual (Lolium multiflorum Lam.) and perennial ryegrasses on 3DCM-groomed and non-groomed fairway turfs of 'Tifway' hybrid bermudagrass, zoysiagrass [Zoysia matrella (L.) Merr. 'Cavalier'], and seashore paspalum (Paspalum vaginatum Sw. 'Sea Isle 1'). The study was arranged as a randomized complete block split-split-plot with three replications. Species whole main plots were split into three grooming intervals, which were further split into four overseeding treatments. Data were collected assessing visual turf quality, visual turf cover, leaf area index, clipping yield, shoot density, and biomass partitioning. Results indicate annual ryegrass alone and an annual/perennial ryegrass overseeding mix provided acceptable turf quality, but did not improve turf recovery over perennial ryegrass alone in 'Tifway' or 'Sea Isle 1' turfs. In 'Cavalier' turfs, summer quality was affected by overseeding treatment as follows: control > annual > annual/perennial > perennial. The overseeding tolerance of the warm-season turfgrasses was as follows: 'Sea Isle 1' > 'Tifway' > 'Cavalier'. Differences in canopy architecture of warm-season turfgrasses were related to the overseeding tolerance of each species and used to explain plant competition during the spring transition period. Grooming by 3DCM improved late-season turf quality and reduced scalping in 'Tifway'. Overseeding establishment and canopy architecture were not affected by 3DCM.

The implicit function model is nowadays generally applied to a lot of fields that need 3D, such as computer game, cartoon or for specially effect film. So far, most hardware are still to support the polygon-mesh model but not implicit function model, so polygon-mesh model is still the mainstream of computer graphics. However, translation between the two representation models becomes a new research topic. This paper presents a new method to translate the triangles mesh model into the implicit functions model. The main concept is to use the binary space-partitioning tree to divide the points and patches in the triangle mesh model to create a hierarchical structure. For each leaf node in this hierarchical structure, we would generate a corresponding implicit function. These implicit functions are generated by the genetic algorithm. And the internal nodes in this hierarchical structure are blended by the blending operators. The blending operators make the surface become smooth and continual. The method we proposed reduces the data in a large amount because we only save the coefficients of the implicit surface. And the genetic algorithm can avoid the high computing complexity.

No description available.

No description available.

The purpose of this project is to design a computer program to help children understand a strategy for changing vantage points within an imagined space and gain knowledge of how spatial transformations work. The developed software, called Viewpoints, presents a virtual three-dimensional environment to be explored and modified by the user. Object and camera manipulations are illustrated through animation. Furthermore, the program was designed to have an intuitive interface and be easy to access. This should allow the software’s target audience of children to focus on the spatial orientation and spatial visualization aspects. A small study evaluated the software in terms of content, instructional design, technical quality, student use, and instructor use. The study provided valuable feedback on how to improve Viewpoints in the future. Information gathered suggests the issue of speed should be addressed and supplemental materials should be added.

Eddy current testing is a widely-used examination of the nondestructive testing method. According to the theory of electromagnetic induction, the coil impendence varies with the interaction between the coil magnetic field and the eddy current magnetic field. By observing the variations of the phase angle and the impendence plane diagram, the influence of different defects and factors are evidently presented. The purpose of this study is to analyze the three-dimensional defects of eddy current testing by means of the finite element method. To begin with, a complete 3-D electromagnetic model in eddy current testing by finite element software package COMSOL Multiphysic was created. Then the impendence plane diagram and evaluation curves are drawn by the mathematics software package MATLAB to show the variations of the impendence and the phase angle. Moreover, the results show the effect of reducing testing errors. The simulation of 3-D defect model can provide more comparable data for experimentalists. So that the problem of inappropriate judgement can be prevented, and then the accuracy in eddy current testing can be enhanced.

Nahua reservoir is an important water resource for supplying drinking water to the Tainan area and a part of Kaohsiung in Taiwan. In recent years, Nanhua reservoir suffers eutrophication problems as many other reservoirs in Taiwan. In order to study eutrophication problems in reservoirs, a three-dimensional hydrodynamic and water quality model has been constructed using the FVCOM (Finite Volume Coastal Ocean Model) model to simulation the hydrodynamics, the nutrient dynamics and the phytoplankton growth in the Nanhua reservoir. The modeling of 3D hydrodynamics is the basic module dominating the circulation in the reservoir. The 3D eutro-dynamics are also calculated by the water quality module, which includes the dynamic variations of chlorophyll-a (Chl-a), dissolve oxygen (DO), carbon biological oxygen demand (CBOD), ammonia nitrogen (NH3-N), nitrate nitrogen (NO3-N), organic nitrogen (ON), phosphate (PO4) and organic phosphorus (OP). The model was first calibrated with the data measured in 2007 and, then, verified with the 2008 data. The model results are in reasonable agreement with the field measurements, both in the calibration and the verification phases. The water level variations are influenced by daily supply for the drinking water treatment and the inflows from the catchment and from Chiashian aqueduct during the dry season in spring. Nutrients are mainly carried into the reservoir through these routes. The residence time in the reservoir and the phytoplankton response with the nutrient loads are calculated. The model results indicated that phytoplankton growth is limited by low temperature and long residence time during the winter. The chlorophyll levels are getting higher from spring through out summer, which is due to enough sun lights and high nutrient loads carried by the catchment runoff. Surface temperatures are higher then the bottom layers causing stratification that worsen the eutrophication problems. Besides the comparisons by hydrodynamic and water quality parameters, the Carlson Trophic State Index (CTSI) has been calculated to categorize the eutrophication levels in the reservoir, which have shown good agreement with the CTSI calculated from EPA sampling data. Therefore, the model can be used as a tool for water quality management in the Nanhua reservoir.

Techn. Univ., Diss.--Wien, 2007.