Digital Commons Network^™

Itera- Tive Reconstruction Framework For High-Resolution X-Ray Ct Data, Thomas Matthew Benson

Masters Theses

Small animal medical imaging has become an important tool for researchers as it allows noninvasively screening animal models for pathologies as well as monitoring dis- ease progression and therapy response. Currently, clinical CT scanners typically use a Filtered Backprojection (FBP) based method for image reconstruction. This algorithm is fast and generally produces acceptable results, but has several drawbacks. Firstly, it is based upon line integrals, which do not accurately describe the process of X-ray attenuation. Secondly, noise in the projection data is not properly modeled with FBP. On the other hand, iterative algorithms allow the integration of more complicated sys- …

Isosurface Extraction In The Visualization Toolkit Using The Extrema Skeleton Algorithm, Subha Parvathy Mahaadevan

Masters Theses

Generating isosurfaces is a very useful technique in data visualization for understanding the distribution of scalar data. Often, when the size of the data set is really large, as in the case with data produced by medical imaging applications, engineering simulations or geographic information systems applications, the use of traditional methods like marching cubes makes repeated generation of isosurfaces a very time consuming task. This thesis investigated the use of the Extrema Skeleton algorithm to speed up repeated isosurface generation in the visualization package, Visualization Toolkit (VTK). The objective was to reduce the number of non-isosurface cells visited to generate …

3d Visualization Modules For Chemical Engineering – A Web-Based Approach Using Java And Opengl, Sharad Anant Gupta

Masters Theses

The main objective of this work is to implement web-based educational modules for chemical engineering students. Phase behavior is a topic with which the students seem to struggle with, particularly for mixtures, where a 2-D representation of the phase diagram falls far short of the understanding a 3-D model can provide. Using the platform-independence of Java and the graphics capability of OpenGL, three phase diagram Java applets have been developed. Users can view these web-based 3D applets by installing a plug-in. These modules provide users with an ability to rotate the 3D models, slice through them, zoom into them and …

A Class Of Functions That Are Quasiconvex But Not Polyconvex, Catherine S. Remus

Masters Theses

In 1991 V. Sverak [11] gave an example of a function that was invariant and quasiconvex but not polyconvex. We have generalized this example to a wide class of functions that meet certain ellipticity and growth conditions. Quasiconvexity is one necessary and sufficient condition for the existence of solutions to the minimization problem in elliptic P.D.E. theory. Invariance is frequently a requirement of the stored energy function in Calculus of Variation approaches to elasticity problems.

Monte Carlo Simulations And Analysis Of Single-Molecule Detection And Imaging, Peter Williams

Masters Theses

Computer modeling and analysis methods are developed for two modes of operation of an instrument for sensitive fluorescence detection of individual dye-labeled molecules in solution. First, Monte Carlo simulations of experiments for single-molecule imaging (SMI) are extended to include effects of sample flow, sticking of molecules to surfaces, and the finite depth-of-focus of the optics. The results have a bearing on a patented method for high-speed single-molecule DNA sequencing. They indicate that the imaging of freely moving fluorescent labels within a microfluidic flowcell will be considerably more involved than that of immobilized molecules at a surface, which is the usual …

Integrated Visualization Of Diffusion Tensor And Functional Mri, Nathaniel Richard Fout

Masters Theses

To understand the morphology, structure, and function of the human brain and the underlying relationships therein has long been a goal of mankind. Technologies are constantly emerging and evolving in an effort to realize this goal, with each new development potentially providing another piece of the puzzle. Among those technologies are advanced imaging modalities such as Diffusion Tensor MRI (DT-MRI) [2] and Functional MRI (fMRI) [8], whose purpose is to provide deeper insight into the neural network connecting functional units of the cerebral cortex. More specifically, DT-MRI captures a description of the fibrous structures (such as nerve fibers) in the …

Fractal Images Generated By Newton's Method.", Jennifer Corte

Masters Theses

We investigate the behavior of Newton's Method for finding roots applied to complex-valued functions of complex variables. This re- quires an analysis of iteration of rational functions. The fractal nature of Newton's Method in the complex plane gives us intricate and beautiful images. By investigating select functions we attempt to generalize a pattern of behavior.

Structural And Stratigraphic Investigations At The Southwest End Of The Tellico-Sevier Syncline, Southeast Tennessee, Milan A. Heath Ii

Masters Theses

The southern Appalachian Valley and Ridge is composed of a wedge of Cambrian through Pennsylvanian siliciclastic and carbonate rocks, deformed during latest Paleozoic by the collision of Laurentia and Gondwana. This collision caused the southern Appalachian foreland fold-thrust belt to deform as a critically tapered wedge. This study utilized structural and stratigraphic data to examine the mechanical behavior and timing of emplacement of the southwest end of the Tellico-Sevier syncline within this wedge. The study area is located in southeast Tennessee at the southwest end of the Tellico-Sevier syncline, which is in the first Valley and Ridge thrust sheet west …

Trochoidal Electron Impact Time-Of-Flight Mass Spectrometry Of Chlorodifluoromethane, Wesley Daniel Robertson

Masters Theses

A Time-of-Fight mass spectrometer (TOF-MS) equipped with both a standard electron gun and a trochoidal electron monochromator was constructed and made operational and used to study ionization processes of the molecule Chlorodifluoromethane (CHF₂Cl). The appearance energies of both the parent ion (CHF₂Cl⁺) and the most intense fragment ion (CHF₂⁺) were carefully analyzed and it was observed that the energy for formation of the parent ion, (CHF₂Cl⁺) at 12.50 eV, was at a higher energy than the fragment ion, (CHF₂⁺) at 12.25 eV. This phenomenon …

A Coarse-Grain Parallel Implementation Of The Block Tridiagonal Divide And Conquer Algorithm For Symmetric Eigenproblems., Robert M. Day

Masters Theses

Cuppen’s divide and conquer technique for symmetric tridiagonal eigenproblems, along with Gu and Eisenstat’s modification for improvement of the eigenvector computation, has yielded a stable, efficient, and widely-used algorithm. This algorithm has now been extended to a larger class of matrices, namely symmetric block tridiagonal eigenproblems. The Block Tridiagonal Divide and Conquer algorithm has shown several characteristics that make it suitable for a number of applications, such as the Self-Consistent-Field procedure in quantum chemistry.

This thesis discusses the steps taken to implement a coarse-grain parallel version of the Block Tridiagonal Divide and Conquer algorithm, suitable for a parallel supercomputer or …

Sparta: A Graphical User Interface For Malicious Mobile Code Fingerprint-Ing., Victor P. De Cerqueira

Masters Theses

This thesis introduces and describes SPARTA (for Stochastic Profiling Application for the Rendering of Trees and Automata), a graphical user interface used as a front end to a collection of tools written in C that collectively convert a log of registry system calls performed by an application into binary descriptions of PSTs (for Probabilistic Suffix Trees) and PSAs (for Probabilistic Suffix Automata), which are models used to represent application behavior on Windows-based systems. SPARTA works by rendering these binary descriptions into graphical form, showcasing a variety of features intended to make the user interaction with PSTs and PSAs informative and …

Geology Of Part Of The Southwestern Brushy Mountains, Inner Piedmont, North Carolina, And The Geochemistry Of Western Inner Piedmont Migmatite, James L. Kalbas

Masters Theses

The newly defined boundary between the western and eastern Inner Piedmont belts has been the focus of several recent tectonic studies in the southern Appalachians. Specifically, the Brindle Creek fault was recognized in southwestern North Carolina as a thrust that juxtaposed Siluro-Devonian-age paragneisses (now-known) and Devonian and Mississippian granites atop Neoproterozoic- to Cambrian-age paragneisses, Middle Ordovician volcanic and metasedimentary rocks, and Ordovician intrusive units.

Detailed geologic mapping in the Kings Creek 7.5-minute quadrangle, southwestern Brushy Mountains, Caldwell County, North Carolina, revealed the northeastern continuation of the thrust. Recognition of the northeastern extension of the fault, and analysis of small -scale …

Thermal Evolution Of Planetesimals And Protoplanets In The Terrestrial Planet Region: Code Optimization And Implementation On A Distributed Grid Using Netsolve, Amitabha Ghosh

Masters Theses

A code for asteroidal heat transfer and growth is optimized for performance. The Gauss elimination routine for the solver is replaced by a sparse matrix routine. Finite element matrix assembly operations are rewritten to reduce operations involving 3D arrays to 1D. Advantage is taken of the sparse matrix structure of finite element matrices in reducing 2D arrays to 1D. The number of vector touches are reduced to the extent possible, by carrying over statements from one iteration to the next. The number of do loops are reduced by merging several do loops into one. The optimization reduced the CPU time …