Digital Commons Network^™

Three-Dimensional Shape Characterization For Particle Aggregates Using Multiple Projective Representations, Jonathan Paul Corriveau

Theses and Dissertations

Shape descriptors are used extensively in computer vision/automated recognition applications such as fingerprint matching, robotics, character recognition, etc. The conventional two-dimensional shape descriptors used in these applications do not readily lend themselves to compact representations in three dimensions. The situation is even more challenging when one attempts to numerically describe the three-dimensional shapes of a mixture of objects such as in an aggregate mix.

The goal of this study is the design, development and validation of automated image processing algorithms that can estimate three-dimensional shape-descriptors for particle aggregates. The thesis demonstrates that a single set of numbers representing a composite …

Daubechies And Quadratic B-Spline Wavelets For Automated Early Diagnosis Of Alzheimer's Disease, Genevieve Jacques

Theses and Dissertations

Alzheimer's disease is a neurological disorder characterized by nerve degeneration and neuronal death. The diagnosis of Alzheimer's disease at an early stage is a major concern due to the lack of a standard and effective diagnosis procedure available to community healthcare providers, as well as the increasing numbers of the elderly population affected. Clinical evaluation, the standard AD diagnostic procedure conducted at major university hospitals and research clinics, achieves, on average, a positive predictive value of 93%, with a sensitivity of 83%, specificity of 55% and an overall accuracy of 75%. An effective and objective tool for early diagnosis of …

Heterogeneous Multi-Sensor Data Fusion Using Geometric Transformations And Parzen Windows For The Nondestructive Evaluation Of Gas Transmission Pipelines, Joseph Anthony Oagaro

Theses and Dissertations

The natural gas transmission pipeline network in the United States is a key component of the nation's energy supply infrastructure and extends for over 280,000 miles and has an average age of over 60 years. The integrity of the pipeline is maintained by periodic inline inspections using magnetic or ultrasonic pigs. Defect characterization algorithms developed using current pigging data are hampered by the fact that single inspection techniques (either magnetic or ultrasonic) do not yield sufficient information for accurately and repeatably characterizing defects. This thesis demonstrates that defect characterization algorithms using multiple inspection techniques can accomplish this task. In particular, …

An Investigation Of Multi-Dimensional Evolutionary Algorithms For Virtual Reality Scenario Development, Scott Papson

Theses and Dissertations

Virtual reality (VR) has emerged as a powerful visualization tool for design, simulation, and analysis in modem complex industrial systems. The primary motivation for this thesis is to develop a framework for the effective use of VR in design-simulation-analysis cycles, particularly in situations involving large, complex, multi-dimensional data-sets. This thesis develops a framework that is intended to support not only the integration of such data for visual, interactive, and immersive displays, but also provides a method for performing risk analysis. Previously "static" VR environments are enhanced with time-evolutionary capabilities. Four candidate algorithms are evaluated for this purpose – deterministic modeling, …

Vlsi Implementation Of An Efficient Method For The Computation Of Line Spectral Frequencies, David L. Reynolds

Theses and Dissertations

In speech coding applications using linear predictive techniques, the computation of line spectral frequencies (LSFs) from the predictor coefficients is an extremely computationally intensive task. The unique properties of the symmetric and antisymmetric polynomial roots limit the region which must be searched, however it is still necessary to perform a root-finding algorithm on a high-order polynomial.

Certain algorithms have been developed to reduce the complexity of the root finding exercise. One such algorithm, developed by Ramachandran and Kabal, takes advantage of certain properties of the symmetric and antisymmetric polynomials to map the upper portion of the unit circle onto the …

New Product Launch Decisions Under Competition And Uncertainty: A Real Options And Game-Theoretic Approach To New Product Development, James O. Ostler

Theses and Dissertations

New product development is central to many firms' future success. Not only as a means to continue to maintain their piece of the market, but product development can also be a strategic means for a company to diversify, and/or alter focus to adapt to changing market conditions.

Most of the research in new product development has been on how to do it cheaper and faster than the next guy. However, early commercialization does not guarantee a position of strength in the market. Failures of EMI in CT scanners and Xerox in personal computers illustrate that being first to market does …

Dynamic Stability And Handling Qualities Of Small Unmanned-Aerial-Vehicles Unmanned-Aerial-Vehicles, Tyler Michael Foster

Theses and Dissertations

General aircraft dynamic stability theory was used to predict the natural frequencies, damping ratios and time constants of the dynamic modes for three specific small UAVs with wingspans on the scale from 0.6 meters to 1.2 meters. Using USAF DatCom methods, a spreadsheet program for predicting the dynamic stability and handling qualities of small UAVs was created for use in the design stage of new small UAV concept development. This program was verified by inputting data for a Cessna-182, and by then comparing the program output with that of a similar program developed by DAR Corporation. Predictions with acceptable errors …

A Finite Element Simulation Of Temperature And Material Flow In Fricton Stir Welding, Mark J. Lasley

Theses and Dissertations

The purpose of this research was to use the Transvalor S.A. product, Forge3, to develop a finite element simulation of the friction stir welding process that improves the predictability of temperature evolution and material flow within the plunge portion of the process. Previous modeling created more heating within the billet than experimental results, probably due to the simplification of the simulation with adiabatic boundary conditions. More realistic tooling temperatures were included in this model as these affect heat evolution which is a determining factor in microcrystalline growth. These results were validated by experimental efforts using a billet and tooling instrumented …

Byu Micro-Sar: A Very Small, Low-Power Lfm-Cw Synthetic Aperture Radar, Michael Israel Duersch

Theses and Dissertations

Brigham Young University has developed a low-cost, light-weight, and low power consumption SAR for flight on a small unmanned aerial vehicle (UAV) at low altitudes. This micro-SAR, or uSAR, consumes only 18 watts of power, ideal for application on a small UAV. To meet these constraints, a linear frequency modulation-continuous wave (LFM-CW) transmit signal is utilized. Use of an LFM-CW signal introduces some differences from the typical strip map SAR processing model that must be addressed in signal processing algorithms. This thesis presents a derivation of the LFM-CW signal model and the associated image processing algorithms used for the uSAR …

A Method For Winding Advanced Composites Of Unconventional Shapes Using Continuous And Aligned Fibers, Abraham K. Allen

Theses and Dissertations

Advanced composites are extremely strong, rigid, and light, even when compared with advanced metals. Advanced composites are replacing high-tech metals as the material of choice for aerospace engineering. However, the processes used to manufacture advanced composites generally lose some of the properties of the materials by their process limitations.

One process that keeps the theoretically awesome qualities of the composite materials in tact is filament winding. Filament wound parts are used as rocket shells, bicycle frame tubes, drive shafts, pressure vessels, etc. Filament winding is an automated process and makes reliable parts to close tolerances. If a straight tube were …

Characterization Of Porous Media And Refractory Materials, Xin Chen

Doctoral Dissertations

Because of its unique advantages on energy savings and casting complex shaper, Lost Foam Casting (LFC) has been widely used as a replacement to the conventional techniques (sand and investment castings). In order to continuously improve the quality of the Lost Foam Casting process for reducing scrap rate and increasing energy savings, the US Department of Energy through its National Industrial Competitiveness through Energy, Environment, and Economics (NICEEE) program sponsored the present study to develop new characterization techniques for enhancing the understanding of the fundamental properties of the refractory materials used in The Lost Foam Casting process. In this study, …

An Adaptive Tool-Based Telerobot Control System, Ge Zhang

Doctoral Dissertations

Modern telerobotics concepts seek to improve the work efficiency and quality of remote operations. The unstructured nature of typical remote operational environments makes autonomous operation of telerobotic systems difficult to achieve. Thus, human operators must always remain in the control loop for safety reasons. Remote operations involve tooling interactions with task environment. These interactions can be strong enough to promote unstable operation sometimes leading to system failures. Interestingly, manipulator/tooling dynamic interactions have not been studied in detail. This dissertation introduces a human-machine cooperative telerobotic (HMCTR) system architecture that has the ability to incorporate tooling interaction control and other computer assistance …

Convergence And Robustness Issues In Computational Fluids, Xiaoqiang Zeng

Doctoral Dissertations

The present research develops two methods to improve the convergence and robustness of CFL algorithm, the triple time method and error- limited time step ramping method.

A general formulation of the triple time scheme is developed by introducing three pseudo time-marching steps to control three preconditionings for artificial dissipation, non-linear equation iteration convergence and linear equation iteration convergence separately. It is proven that the triple time method can be degenerated to the single time method and the multiple DDLGS iteration method at special cases.

Stability analysis is used to choose the optimum combination of three preconditionings from the steady preconditioning, …

High Accuracy Distributed Target Detection And Classification In Sensor Networks Based On Mobile Agent Framework, Xiaoling Wang

Doctoral Dissertations

High-accuracy distributed information exploitation plays an important role in sensor networks. This dissertation describes a mobile-agent-based framework for target detection and classification in sensor networks. Specifically, we tackle the challenging problems of multiple- target detection, high-fidelity target classification, and unknown-target identification.

In this dissertation, we present a progressive multiple-target detection approach to estimate the number of targets sequentially and implement it using a mobile-agent framework. To further improve the performance, we present a cluster-based distributed approach where the estimated results from different clusters are fused. Experimental results show that the distributed scheme with the Bayesian fusion method have better performance …

Synthesis And Ordering Of Nanostructures Using Laser Light, Yingfeng Guan

Doctoral Dissertations

This dissertation focuses on the formation of 1-D and 2-D nanoscale structures induced by the KrF excimer UV laser irradiation of silicon (λ=248 nm). Relatively low laser energy density (E_d<=1 J/cm²) is required to produce nanostructures. Alignment of 2-D nanoripple structures and nanoprotrusions has been realized by using Lloyd’s mirror configuration.

Laser-generated silicon microcone arrays were used as templates for the growth of nanocolumns. The formation mechanism of the microstructure is reviewed, and the origin and growth of nanocolumns are discussed. The formation mechanism of nanocolumns requires highly localized melting, which explains why they fail to form on …

A Study Of The Evolution Of Laser-Induced Periodic Surface Microstructures On Silicon And Electronic Transport In Composite Carbon Nanotube Networks, Stephen Jesse

Doctoral Dissertations

This dissertation addresses two main topics, the formation of micron-scale surface structures on single crystal silicon by irradiation with a KrF (248 nm) pulsed excimer laser source, and an investigation into electronic transport through composites of polymer (PMMA) and single-walled carbon nanotubes. It is shown that the spacing between laser-generated surface structures is determined primarily by the melt time and that the crystal orientation of the substrate can determine whether surface structures will form at all and also influence the shape of individual surface structures. During the melt/solidification cycle, the shape of liquid-vapor interface in modified by surface tension, and …

Fundamental Studies Of X-Ray And Secondary Electron Spectroscopy, Staya Prasad Mulapudi

Doctoral Dissertations

Microanalysis of submicron particles in the Scanning Electron Microscope (SEM) is only possible by using low incident electron beam energies due to smaller interaction volume and suppressed beam induced charging. Such low beam energies must use L- and M- lines rather than the familiar K-lines. The information about the fundamental parameters of X-ray emission and transport at low energies is limited, so the use of L- and M- lines is problematic. The rate of generation of X-rays from an element irradiated at some energy E depends on the product of the ionization cross-section (E) and the fluorescent yield . Unfortunately …

Modeling And Source Apportionment Of Primary And Secondary Pm2.5 In The Atmosphere, Prakash Doraiswamy

Doctoral Dissertations

Source apportionment of PM_2.5 is important to identify the source categories that are responsible for the concentrations observed at a particular receptor. Although receptor models have been used to do source apportionment, they do not fully take into account the chemical reactions (including photochemical reactions) involved in the formation of secondary fine particles. Secondary fine particles are formed from photochemical and other reactions involving precursor gases such as sulfur dioxide (SO₂), oxides of nitrogen (NO_x), ammonia (NH₃) and volatile organic compounds (VOC). The purpose of this research work was to model primary and …

Acoustic Wave Based Biosensor, Aditya A. Vijh

Masters Theses

Quartz Crystal Microbalances (QCMs) have been widely used for detection of various chemical and biological species in liquid media. In this work an improved binding of Protein A and IgG molecules on QCM biosensors by modifying the gold surface of the quartz crystal with an ultra thin polystyrene film followed by an acidic treatment has been reported. Protein A and IgG immobilizations on quartz crystals with the polystyrene film represented a 65% increase and a 40% increase respectively when compared to immobilization done directly onto the crystals. Atomic Force Microscopy (AFM) has been used to investigate and study the biomolecular …

Design And Parameter Identification Of A Discrete Variable Transmission System, Kelley Parker Brown

Masters Theses

Complex and expensive electro-hydraulic systems have shouldered the workload for remote cleanup operations in radiological and toxicological areas in the past; the payload, reach and speed requirements of most applications have demanded their use. Electromechanically actuated systems (EAS) however offer an alternative that in comparison is much more reliable and maintainable. The problems faced in implementing the EAS are in high payload operations where the hydraulic systems hold a clear power density advantage. For the EAS to compete in the area of torque, very large DC motors have been implemented which make them obsolete in restricted work space areas and …

Effect Of Micro-Fabric On Consolidation Behavior Of Reconstituted Kaolin Clay, Alexander Page Davis-Smith

Masters Theses

The effect of micro-fabric (i.e. geometric arrangement of platelets) on the one-dimensional consolidation behavior of reconstituted kaolin clay is evaluated using a series of controlled-rate-of-strain (CRS) and incremental load (IL) consolidation tests. The causes and implications of changes in micro-fabric are also explored. Micro-fabric has been altered by adding a dispersing agent to the slurry during specimen preparation; and the changes in micro-fabric have been observed with scanning electron microscope (SEM) images and x-ray diffraction analysis. Properties of the pore fluid are found to affect micro-fabric, even in the presence of significant mechanical stresses. It is observed that the changes …

Use Of The Gps Reciprocal Heading Method For Determining Pitot-Static Position Error In Helicopter Flight Testing, Rucie James Moore

Masters Theses

This thesis is an evaluation of using the Global Positioning System (GPS) reciprocal heading method to determine pitot-static position errors in helicopter flight testing. Determination of position error is a fundamental flight test task that must occur early in a test program, as all other results with regard to airspeed rely on the data. The test determines errors of the pitot-static system that cause inaccurate indication of airspeed to the pilot. The measured course, a currently approved method, provides a measure of the helicopter’s groundspeed by flying the helicopter over a known distance and converting elapsed time into the speed …

The Design Of Medium Access Control (Mac) Protocols For Energy Efficient And Qos Provision In Wireless Sensor Networks, Yang Liu

Masters Theses

This thesis work focuses on innovative design of media access control (MAC) protocols in wireless sensor networks (WNSs). The characteristics of the WSN inquire that the network service design considers both energy efficiency and the associated application requirement. However, most existing protocols address only the issue of energy efficiency.

In this thesis, a MAC protocol has been proposed (referred to as Q-MAC) that not only minimized the energy consumption in multi-hop WSNs, but also provides Quality of Service (QoS) by differentiating network services based on priority levels prescribed by different applications. The priority levels reflect the state of system resources …

The Synthesis And Characterization Of Mesoporous Uranium Oxide Catalysts For Oxidative Destructions Of Volatile Organic Compounds And Clean Air Protection, Cyrus Khezr Riahi-Nezhad

Masters Theses

The overall goal of this research was to investigate a new class of mesoporous uranium oxide catalyst used to destroy a range of volatile organic compounds (VOCs), including aromatics and chlorinated organic compounds under conditions which are applicable for U.S. Department of Energy (DOE) facilities and U.S. industries.

Uranium oxides are known to have high efficiency and long-term stability when used to destroy volatile organic compounds (VOCs) when compared with some of the commercial catalysts, such as precious metals, TiO₂, and Co₃O₄ catalysts. Two key factors limiting catalytic activities of uranium oxides prepared by conventional …

Causal Analysis Of Fatal Trenching Accidents, John Patrick Wagner

Masters Theses

A study was performed by the Construction Industry Research and Policy Center at The University of Tennessee, Knoxville to identify causation for U.S. trench collapse fatalities in the construction industry that occurred during the years 1997-1999. Of the 1217 fatality case files analyzed, 44 were categorized as trench collapse fatalities. The 44 trench collapse case files were analyzed and the contributed factors of the fatalities were identified in an effort to determine the causation of collapses. The results of the study showed a large number of trenches without any type of protective devices being used. The findings of the fatal …

A Computer Modeling Approach Using Critical Resource Diagramming Network Analysis In Project Scheduling, Vincent Gilles Delgado

Masters Theses

The problem of resource constrained project scheduling (RCPSP) continues to be an important topic in project management. Different scheduling processes have been introduced to solve cases of RCPSP. Most of the developed methods are based on a network analysis approach. The two main technique of project network analysis used for planning, scheduling, and control are PERT and CPM. These approaches assume unlimited resource availability in project network analysis. In realistic projects, both the time and resource requirements of activities should be considered in developing network schedules. Another particularity of the methods created, so far, is the focus on activities during …

Effects Of Pressure And Equivalence Ratio On Minimum Ignition Energies Of Methane-Air Mixtures And Effect Of Pressure On Breakdown Threshold Energies Of Methane And Air, Sameer Vidyadhar Bondre

Masters Theses

An experimental investigation is conducted to determine the effect of pressure on breakdown threshold energies of methane and air. In addition the effect of pressure and equivalence ratios on minimum ignition energies of methane-air mixtures are also investigated. The pressures for the breakdown threshold energy experiments are varied from 0.02 to 1.17 MPa, and pressures and equivalence ratios for minimum ignition energy experiments are varied from 0.1 to 1.04 MPa and 0.6 to 1.2, respectively. The gas breakdown and the ignition of the methane-air mixture is achieved using a laser-induced spark from a 5.5 ns pulse Q-switched Nd:YAG laser at …

Hardware Acceleration Of The Embedded Zerotree Wavelet Algorithm, Suresh S. Polisetty

Masters Theses

The goal of this project was to gain experience in designing and implementing a microelectronic system to acclerate the execution of a time-consuming software algorithm, the Embedded Zerotree Wavelet (EZW), which is used in multimedia applications. The algorithm was implemented using MATLAB to be certain it was fully understood and to serve as a validation reference. Then, the algorithm was mapped into a hardware description language, VHDL, and its resulting implementation verified with the golden reference. The hardware description was then targeted to a field-programmable gate array (FPGA). Significant acceleration was achieved since the hardware implementation in a FPGA (Xilinx …

Analysis Of Pilot Performance Using Precision Visual Flight Rules, Thomas Morrissey

Masters Theses

Precision Visual Flight Rules (PVFR) seeks to allow helicopter pilots to fly predetermined routes in high density traffic areas with greater precision by using a Global Positioning System (GPS). An analysis of the cross-track error during the PVFR developmental testing is presented. The primary objective is to determine the dominant factors which effect pilot performance using this higher standard of precision. Factors which are investigated include: total flight time, recent helicopter flight time, pilot ratings, and experience with the particular aircraft and GPS model. A conclusion is presented on which factors need to be addressed before opening up PVFR routes …

Thermal Modeling And Imaging Of As-Built Automotive Parts, Vijaya Priya Muthusamy Govindasamy

Masters Theses

Simulation is of significant importance in the automotive industry and can be done for various applications ranging from fluid flow analysis to complex thermal management of components. This thesis describes the method and necessary requirements for thermal modeling of automotive parts. Simulation of under hood and under vehicle automotive poses several challenges, the shape and complexity of the geometry used being the first and foremost to be considered. This thesis addresses the simulation of thermal images of as-built automotive parts using the 3D meshes generated from 3D modeling tools, CAD meshes and reverse engineered meshes.

Thermal modeling requires complete knowledge …