Engineering Commons^™

Multispectral Imaging For Face Recognition Over Varying Illumination, Hong Chang

Doctoral Dissertations

This dissertation addresses the advantage of using multispectral narrow-band images over conventional broad-band images for improved face recognition under varying illumination. To verify the effectiveness of multispectral images for improving face recognition performance, three sequential procedures are taken into action: multispectral face image acquisition, image fusion for multispectral and spectral band selection to remove information redundancy.

Several efficient image fusion algorithms are proposed and conducted on spectral narrow-band face images in comparison to conventional images. Physics-based weighted fusion and illumination adjustment fusion make good use of spectral information in multispectral imaging process. The results demonstrate that fused narrow-band images outperform …

Modeling Of Algan/Gan High Electron Mobility Transistor For Sensors And High-Temperature Circuit Applications, Sazia Afreen Eliza

Doctoral Dissertations

With the most advanced and mature technology for electronic devices, silicon (Si) based devices can be processed with practically no material defects. However, Si technology has difficulty meeting the demand for some high-power, high-speed, and high-temperature applications due to limitations in its intrinsic properties. Wide bandgap semiconductors have greater prospects compared to Si based devices. The wide band gap material system shows higher breakdown voltage, lower leakage, higher saturation velocity, larger thermal conductivity and better thermal stability suitable for high-power, high-speed, and high-temperature operations of the devices. In recent years, GaN based devices have drawn much research attention due to …

Nanostructured Chitosan Membranes For Filtration, Keyur Desai

Doctoral Dissertations

Chitosan is a non-toxic and biodegradable biopolymer derived from naturally occurring chitin. It has excellent metal binding and anti-microbial properties which could be beneficial in air and water filtration applications. Nanofibers have distinctly high surface area to volume ratio.

Electrospinning is a process by which nano-sized polymer fibers can be produced using an electrostatically driven jet of polymer solution. The fibers are collected as a non-woven mat and offer a high surface area to volume ratio.

Electrospinning of pure chitosan is hindered by its limited solubility in aqueous acids and high molecular weight with high degree of inter and intra …

Development Of A Computational Model To Predict The In Vivo Contact Mechanics Of Modern Total Knee Arthroplasty, Adrija Sharma

Doctoral Dissertations

This dissertation focuses on the development of a computationally efficient and fast method that incorporates the kinematics obtained from fluoroscopy and extends it to the prediction of the in-vivo contact mechanics at the femoro-tibial articulation in modern knee implants for the deep knee bend activity. In this endeavor, this dissertation deals with the use of an inverse dynamic rigid body model characterizing the slip and roll behavior observed in the femoro-polyethylene articulation and a coupled deformation model where the polyethylene in knee implants are modeled as hexahedral discrete element networks. The performance of this method is tested by comparing force …

A Study Of The Indentation Size Effect In Copper, Jeremy Harper Strader

Doctoral Dissertations

A simple model for an expanding array of screw dislocations is developed to evaluate the size of the containment zone of the geometrically necessary dislocations as it relates to the indentation size effect. The model as developed predicts the same functional form as the Nix-Gao model, H²=H₀²(1+h^*/h), but a new relation for h^* applies that depends only on the Burgers vector and the Taylor constant, where as the Nix-Gao model predicts a strong dependence of the macroscopic hardness and the tip angle. The continuous stiffness method, CSM, is critically examined using experimental …

Uncertainty Minimization In Robotic 3d Mapping Systems Operating In Dynamic Large-Scale Environments, Sreenivas Rangan Sukumar

Doctoral Dissertations

This dissertation research is motivated by the potential and promise of 3D sensing technologies in safety and security applications. With specific focus on unmanned robotic mapping to aid clean-up of hazardous environments, under-vehicle inspection, automatic runway/pavement inspection and modeling of urban environments, we develop modular, multi-sensor, multi-modality robotic 3D imaging prototypes using localization/navigation hardware, laser range scanners and video cameras.

While deploying our multi-modality complementary approach to pose and structure recovery in dynamic real-world operating conditions, we observe several data fusion issues that state-of-the-art methodologies are not able to handle. Different bounds on the noise model of heterogeneous sensors, the …

Mechanical Behavior Of A Ni-Based Crystalline And A Zr-Based Amorphous Materials Subjected To Surface Severe Plastic Deformation, Jiawan Tian

Doctoral Dissertations

A surface-treatment process, surface-severe-plastic deformation (S²PD), is developed and applied on both crystalline and amorphous materials to introduce the plastic deformation in the near-surface layer. A S²PD-processed crystalline component is expected to have enhanced fatigue properties because the refined grains in the near-surface layer and the coarse grains in the interior have good resistance to the crack initiation and propagation, respectively.

The near-surface structures of the processed specimens were characterized by means of the optical microscopy, scanning-electron microscopy (SEM), X-ray diffraction (XRD), and transmission-electron microscopy (TEM). Mechanical properties, such as the microhardness, yield strength, and four-point-bend …

Reliability Analysis Of Hafnium Oxide Dielectric Based Nanoelectronics, Rui Wan

Doctoral Dissertations

With the physical dimensions ever scaling down, the increasing level of sophistication in nano-electronics requires a comprehensive and multidisciplinary reliability investigation. A kind of nano-devices, HfO₂-based high-k dielectric films, are studied in the statistical aspect of reliability as well as electrical and physical aspects of reliability characterization, including charge trapping and degradation mechanisms, breakdown modes and bathtub failure rate estimation.

This research characterizes charge trapping and investigates degradation mechanisms in high-k dielectrics. Positive charges trapped in both bulk and interface contribute to the interface state generation and flat band voltage shift when electrons are injected from the gate …

Localized Corrosion Behavior Of Zr-Based Bulk Metallic Glasses In Neutral Nacl Electrolytes, Brandice Annette Green

Doctoral Dissertations

The electrochemical behaviors the Zr₅₀Cu₄₀Al₁₀, Zr₅₀Cu₃₃Al₁₀Pd₇, and Zr_52.5Cu_17.9Al₁₀Ni_14.6Ti_5.0 BMGs were investigated in NaCl solutions. Both Zr₅₀Cu₄₀Al₁₀ and Zr₅₀Cu₃₃Al₁₀Pd₇ exhibited poor corrosion behaviors. Zr₅₀Cu₄₀Al₁₀ was vulnerable to localized corrosion at the open-circuit conditions (OCC). Zr₅₀Cu₃₃Al₁₀Pd₇ experienced localized corrosion at OCC or at slightly higher potentials. Anodic-polarization of both alloys demonstrated that small increases in …

System-On-Package Low-Power Telemetry And Signal Conditioning Unit For Biomedical Applications, Mohammad Rafiqul Haider

Doctoral Dissertations

Recent advancements in healthcare monitoring equipments and wireless communication technologies have led to the integration of specialized medical technology with the pervasive wireless networks. Intensive research has been focused on the development of medical wireless networks (MWN) for telemedicine and smart home care services. Wireless technology also shows potential promises in surgical applications. Unlike conventional surgery, an expert surgeon can perform the surgery from a remote location using robot manipulators and monitor the status of the real surgery through wireless communication link. To provide this service each surgical tool must be facilitated with smart electronics to accrue data and transmit …

Hardware Development Of An Ultra-Wideband System For High Precision Localization Applications, Cemin Zhang

Doctoral Dissertations

A precise localization system in an indoor environment has been developed. The developed system is based on transmitting and receiving picosecond pulses and carrying out a complete narrow-pulse, signal detection and processing scheme in the time domain. The challenges in developing such a system include: generating ultra wideband (UWB) pulses, pulse dispersion due to antennas, modeling of complex propagation channels with severe multipath effects, need for extremely high sampling rates for digital processing, synchronization between the tag and receivers’ clocks, clock jitter, local oscillator (LO) phase noise, frequency offset between tag and receivers’ LOs, and antenna phase center variation. For …

Magnetic Field Effects On Photocurrent And Photovoltaic Processes In Organic Solar Cells, Zhihua Xu

Doctoral Dissertations

Two mechanisms were investigated to understand the magnetic field effects on photocurrent (MFP), a phenomenon whereby an external magnetic field (MF) can increase or decrease photocurrent in organic solar cells (OSCs). The first one relates to MF-modulated intersystem crossing (ISC) between singlet and triplet polaron pairs and charge transfer (CT) complexes, accounting for the positive MFP in low and high magnetic field, respectively. The second mechanism originates from the interaction between triplet excited states and charge carriers, namely triplet-charge reaction (TCR). External magnetic field was found to reduce the rate constant of TCR, leading to negative MFP.

MFP measurements were …

Mrf Stereo Matching With Statistical Estimation Of Parameters, Mohammad Shafikul Huq

Doctoral Dissertations

For about the last ten years, stereo matching in computer vision has been treated as a combinatorial optimization problem. Assuming that the points in stereo images form a Markov Random Field (MRF), a variety of combinatorial optimization algorithms has been developed to optimize their underlying cost functions. In many of these algorithms, the MRF parameters of the cost functions have often been manually tuned or heuristically determined for achieving good performance results. Recently, several algorithms for statistical, hence, automatic estimation of the parameters have been published. Overall, these algorithms perform well in labeling, but they lack in performance for handling …

Label-Free Mapping Of Near-Field Transport Properties Of Micro/Nano-Fluidic Phenomena Using Surface Plasmon Resonance (Spr) Reflectance Imaging, Iltai Kim

Doctoral Dissertations

My doctoral research has focused on the development of surface plasmon resonance (SPR) reflectance imaging technique to detect near-field transport properties such as concentration, temperature, and salinity in micro/nano fluidic phenomena in label-free, real-time, and full-field manner. A label-free visualization technique based on surface plasmon resonance (SPR) reflectance sensing is presented for real-time and full-field mapping of microscale concentration and temperature fields. The key idea is that the SPR reflectance sensitivity varies with the refractive index of the near-wall region of the test mixture fluid. The Fresnel equation, based on Kretschmann’s theory, correlates the SPR reflectance with the refractive index …

Reliability In Lean Systems, Robert S. Keyser

Doctoral Dissertations

Implementation of Lean manufacturing systems often turn into expensive hit-or-miss propositions. Whereas many organizations that lack immediate success quickly abandon their ‘Lean’ plans in hopes that the next great marketing panacea will solve their efficiency woes, organizations that experience early success often have difficulty in sustaining their Lean efforts. To further exacerbate the dilemma, knowledge of the reliability of Lean systems is currently inadequate. This paper proposes a contemporary Lean paradigm – reliability in Lean systems – through the development of an innovative Lean System Reliability model (LSRM). Principally, LSRM models the reliability of Lean subsystems as a basis for …

Stochastic Modeling And Estimation Of Wireless Channels With Application To Ultra Wide Band Systems, Yanyan Li

Doctoral Dissertations

This thesis is concerned with modeling of both space and time variations of Ultra Wide Band (UWB) indoor channels. The most common empirically determined amplitude distribution in many UWB environments is Nakagami distribution. The latter is generalized to stochastic diffusion processes which capture the dynamics of UWB channels. In contrast with the traditional models, the statistics of the proposed models are shown to be time varying, but converge in steady state to their static counterparts.

System identification algorithms are used to extract various channel parameters using received signal measurement data, which are usually available at the receiver. The expectation maximization …

Safdetection:Sensor Analysis Based Fault Detection In Tightly-Coupledmulti-Robot Team Tasks, Xingyan Li

Doctoral Dissertations

This dissertation addresses the problem of detecting faults based on sensor analysis for tightly-coupled multi-robot team tasks. The approach I developed is called SAFDetection, which stands for Sensor Analysis based Fault Detection, pronounced “Safe Detection”. When dealing with robot teams, it is challenging to detect all types of faults because of the complicated environment they operate in and the large spectrum of components used in the robot system. The SAFDetection approach provides a novel methodology for detecting robot faults in situations when motion models and models of multi-robot dynamic interactions are unavailable. The fundamental idea of SAFDetection is to build …

The Future Of The Operating Room: Surgical Preplanning And Navigation Using High Accuracy Ultra-Wideband Positioning And Advanced Bone Measurement, Brandon C. Merkl

Doctoral Dissertations

This dissertation embodies the diversity and creativity of my research, of which much has been peer-reviewed, published in archival quality journals, and presented nationally and internationally. Portions of the work described herein have been published in the fields of image processing, forensic anthropology, physical anthropology, biomedical engineering, clinical orthopedics, and microwave engineering.

The problem studied is primarily that of developing the tools and technologies for a next-generation surgical navigation system. The discussion focuses on the underlying technologies of a novel microwave positioning subsystem and a bone analysis subsystem. The methodologies behind each of these technologies are presented in the context …

Deformation And Fatigue Behavior Of Bulk-Metallic Glasses (Bmgs), Dongchun Qiao

Doctoral Dissertations

The objectives of the thesis research are 1) to study the strain rate effect on the deformation behavior of bulk-metallic glasses (BMGs), 2) to investigate the loading mode effect on the fatigue behavior of BMGs.

The main results are obtained as follows. At room temperature, during the inhomogeneous deformation, BMGs show the strain softening caused by the increase of the free volume in the shear bands. However, BMGs have a high-energy state and trend to crystallize, especially in the shear bands with the maximum shear stress and the increasing temperature. The instability of BMGs makes it possible for strain hardening. …

Person-Environment Fit And Readiness For Change: Exploring The Moderating Role Of Leader-Member Exchange And Perceived Organizational Support, Joana R.C. Pimentel

Doctoral Dissertations

This paper was aimed at investigating the interplay of multiple facets of personenvironment fit with individual readiness for change; and to expose potential moderators of this relationship, namely organizational support and quality of relationship with supervisors. The extant research on the relationships between person-environment fit and a number of individual- and organization-level outcomes reveals considerable discrepancies, mainly attributed to the measurement of person-environment fit and to potential moderators. With this in mind, moderated multiple regressions (MMR) were conducted in order to test the hypotheses of existing interaction effects.

The results revealed no significant interactions between facets of personenvironment fit and …

Simulating Truck Lane Management Approaches To Improve Efficiency And Safety Of Highways In Knoxville, Tennessee, Adebola Adebisi Adelakum

Masters Theses

Increased globalization has caused large increases in truck traffic on the nation’s interstate system, with much additional growth expected in the coming years. This growth has elevated interest in developing new strategies to address rising levels of truck traffic, especially in dense and congested urban areas. This thesis focuses on the evaluation of several alternative lane management configurations as they compare to the current lane configuration in search of the best fit for operational improvement. This task was performed in two ways – survey and simulation. A survey of 500 long-haul truck drivers was administered in Knoxville, Tennessee, at the …

Numerical Analysis For Determination Of Fiber Orientation In Nonwoven Mats, Lee Reynolds Allen

Masters Theses

The University of Tennessee Space Institute is interested in pitch-based carbon fibers. A need has arisen for characterizing relative alignment of nonwoven fiber mats, produced by the spinning gathering technology implemented. Knowledge of this alignment is relevant in the validation of production methodology as well as aiding in the analysis of carbon fiber composite materials made with the fiber mats. A digital image processing method was developed presented and evaluated in this thesis consisting of three steps: preprocessing using image smoothing, edge detection based upon local intensity gradients, and line detection via the Hough Transform. A summary of typical results …

Resonant Ultrasound Studies Of Quasi-2d NaXCoo2, Timothy Allen Cagle

Masters Theses

Sodium cobaltate possesses all the important traits needed in a material for potential thermoelectric applications yet it shows little regard for the traditional physics of thermoelectrics. As existing theories regarding the phenomenon in Na_xCoO₂ are incomplete, we have set out to elucidate some of the issues by looking into the elastic response of the system. To this effect, we have employed Resonant Ultrasound Spectroscopy to obtain the elastic tensor at various temperatures. As the Na_0.75CoO₂ stoichiometry seemed to potentially offer the most rewards due to a pronounced ground state and anomalous thermopower at higher …

New Consolidation Of Emission And Processing For Air Quality Modeling Assessment In Asia, Yuan Du

Masters Theses

Gridded Asian emission input with fine resolutions for regional photochemical air quality modeling is absent from current studies. A new top-down emission process based on GIS-FORTRAN program has been developed in this study to consolidate the current available regional emissions in Asia and provide model-ready emission input with more flexibility. The INTEX-B anthropogenic emission inventory in 2006 integrated with biogenic from GEIA, as well as biomass burning and ship emissions from TRACE-P has been adopted as the top-level emissions, which are then spatially allocated into grid-cell level by our GIS application. The spatial allocation factors generated for this process are …

The Application Of A Two-Dimensional Sediment Transport Model In A Cumberland Plateau Mountainous Stream Reach With Complex Morphology And Coarse Substrate, Daniel Hale Johnson

Masters Theses

Among river engineers there is growing recognition that the success of a stream restoration project is dependent on the accurate prediction of sediment transport along a reach. To aid the design process, several numerical one- and multi-dimensional models have been developed to quantify in-stream sediment transport and hydraulic characteristics, and multiple sampling techniques have been proposed to establish the upstream sediment supply. However, the governing physical boundaries and variables (i.e., Manning’s ‘n’ variable, energy slope, and upstream sediment supply) required to initiate a sediment transport simulation are time consuming and difficult to measure in the field, and the estimation of …

Design And Development Of An Apd Algorithm Development Board For Positron Emission Tomography, Rakesh Mallem

Masters Theses

Using the PET scanner, three dimensional images of the human body with sufficient detail can be viewed which help physicians to visualize both normal metabolic functions and discover the chemical processes underlying physical abnormalities. Commercial PET scanners employ Photo Multiplier Tubes to detect the anti-matter annihilation photons and amplify the signals to a suitable level for digital sampling. Photomultiplier tubes provide extremely high sensitivity and exceptionally low noise compared to other photosensitive devices currently used to detect radiant energy in the ultraviolet, visible and near infrared regions. A combined magnetic resonance positron emission tomography (MR-PET) modality would require a solid-state …

A Systems Approach To Selecting And Outfitting A Helicopter For Airborne Law Enforcement, Francesco J. Lombardi

Masters Theses

A modern day airborne law enforcement helicopter is an exercise in compromise. Applying a Systems Engineering approach to selecting and outfitting a helicopter for airborne law enforcement can bring order to the process. The Suffolk County Police Aviation Section of New York was used as an example agency profile in analyzing mission requirements, establishing constraints, and analyzing alternatives. A benchmark survey was established for use in comparison.

Benchmark trends indicated power margin and useful load as the primary performance requirements of an airborne platform with a primary mission of Emergency Medical Service (EMS) and a secondary mission of patrol. EMS …

Fault Current Limiting And Protection Circuit For Power Electronics Used In A Modular Converter, Shibani Mishra

Masters Theses

The thesis objective is to safeguard power electronics used in modular converter applications. A new fault current limiting and protection circuit is proposed. The system level fault mitigation assemblies take a long time to remove a fault and within this time the IGBTs used in the Flexible AC Transmission System (FACTS) application will undergo high thermal and mechanical stress. Exposure to such conditions over a prolonged period of time will reduce the device lifetime, which is one of the major reasons why power electronics are not very popular in utility applications. Modular converter approach will reduce the device ratings required …

A High Voltage Ccd Sensor Control Chip For The Large Synoptic Survey Telescope (Lsst), Zuoliang Ning

Masters Theses

This thesis presents the design of a Sensor Control Chip (SCC) developed to provide the required clock and bias signals for the Large Synoptic Survey Telescope’s CCD imagers. The circuit consists of current-summing DACs followed by trans-impedance operational amplifiers to control the rail voltages of the clock signals and bias voltages. The clocks are input to the SCC through LVDS receivers and converted internally to the required amplitude for driving the CCDs. The ASIC is designed to drive clock signals with 20-V adjustable output voltage swing and a maximum output current of 150 mA. The prototype chip has been fabricated …

A Flight Test Study To Assess The Utility Of An Aircraft Referenced 3d Audio Display To Improve Pilot Performance Under High Workload Conditions, Mehendi Hassan Naqvi

Masters Theses

A study to assess the utility of an aircraft referenced 3D audio display was undertaken to determine if there could be any improvements to pilot performance when operating under high workload conditions. Test subjects flew a general aviation light twin-engine aircraft under simulated single-pilot instrument flight rule conditions. Workload was elevated by ensuring each test subject had to execute an unexpected missed approach procedure and simultaneously handle a simulated engine failure. Subjective data was gathered using the NASA Task Load Index and a post-flight questionnaire on perceived performance, workload and situational awareness. Objective data on pilot performance was gathered using …