Engineering Commons^™

Cloud-Induced Uncertainty For Visual Navigation, Alyssa N. Gutierrez

Theses and Dissertations

This research addresses the numerical distortion of features due to the presence of clouds in an image. The research aims to quantify the probability of a mismatch between two features in a single image, which will describe the likelihood that a visual navigation system incorrectly tracks a feature throughout an image sequence, leading to position miscalculations. First, an algorithm is developed for calculating transparency of clouds in images at the pixel level. The algorithm determines transparency based on the distance between each pixel color and the average pixel color of the clouds. The algorithm is used to create a dataset …

Finite Element Analysis Simulations Of Micro And Nano-Electromechanical Sensors For Design Optimization, Nicholas Frank Deroller

Theses and Dissertations

Micro and Nano-electromechanical sensors (MEMS and NEMS) provide a means of actively sensing minute changes in the surrounding environment. Small changes in temperature, momentum, and strain may be sensed in passive modes while greater sensing possibilities exist in active modes. Theoretical femto-gram resolution mass detection and heated element sensing methods may be used while volatile organic compound (VOC) sensing may be achieved when combined with a functionalization layer or device heating. These devices offer a great reduction in cost and offer increased mobility by allowing a "lab-on-chip" solution for the prospective user while also greatly reducing the amount of energy …

Piezotransistive Iii-V Nitride Microcantilever Based Mems/Nems Sensor For Photoacoustic Spectroscopy Of Chemicals, Abdul Hafiz Ibne Talukdar

Theses and Dissertations

Microcantilevers are highly attractive as transducers for detecting chemicals, explosives, and biological molecules due to their high sensitivity, micro-scale dimensions, and low power consumption. Though optical transduction of the mechanical movement of the microcantilevers into an electrical signal is widely practiced, there is a continuous thrust to develop alternative transduction methods that are more conducive to the development of compact miniaturized sensors. Piezoelectric and piezoresistive transduction methods are two of the most popular ones that have been utilized to develop miniaturized sensor systems. Piezoelectric cantilevers, which are commonly made of PZT film, have demonstrated very high sensitivity; however, they suffer …

Influence Of Defects In Epitaxial Graphene Towards Material Growth And Device Performances, Shamaita Shithi Shetu

Theses and Dissertations

Since its invention in 2004, Graphene, a two dimensional array of SP2 bonded carbon atoms has received significant interest by the scientific community due to its unique electrical, optical and mechanical properties. A promising route to the synthesis of large-area graphene, is epitaxial graphene formed by sublimation of silicon atoms from Silicon carbide at elevated temperatures (>1200oC). Although the electronic and mechanical properties of graphene with perfect atomic lattice are outstanding, the structural defects, which may appear during graphene growth, can influence the growth mechanism and material properties. However, deviations from perfection, i.e. introducing dopants in semiconductors often considered …

High Level Control Implementation For A Residential Smart Grid Power System, Hang Xu

Theses and Dissertations

With the environment protection and energy usage efficiency promotion issues concerned more and more by governments and industries these days, smart grid technologies have been in rapid development. On this new technology stage, residential site power management system has become a star. This paper introduces the concept, development of two high level control methods for “Smart Green Power Node” (SGPN), solutions of demand side energy management system. One control algorithm is optimal model method which uses the predictive data of a battery model with electrical parameters and pricing methods, to keep scheduling the optimal control input on the receding time …

Characterization Of Electrodeposited Copper Foil Surface Roughness For Accurate Conductor Power Loss Modeling, Michael B. Griesi

Theses and Dissertations

As computer data rates have increased, designers observed that the standard models for estimating the impact of copper foil surface roughness on conductor loss are limited to a few GHz. The more recent snowball model (a “snowball” estimation of the Huray Model) has demonstrated improved conductor loss predictions up to 50 GHz by estimating the necessary parameters using reasonable assumptions about the geometric surface features of electrodeposited copper foil. Since then, the Huray Model has been incorporated into commercial electromagnetic field simulators. However, a standard method of characterizing the electrodeposited copper foil used in high-speed circuits to directly implement the …

Quantitative Comparison Of Time-Frequency Decomposed Gait Emg Signals, L. Patrick Mitchell

Theses and Dissertations

Falls in the senior population represent an immediate threat to both current and future generations’ quality of life. The results of falls can be disastrous, create a long road to recovery, and in many cases result in death. Hypertension represents a difficult-to-quantify condition which is known to contribute to gait and balance dysfunction. Accurate assessment of conditions such as these represents an area of primary investigative need. In order to meet this need, a new experimental setup is developed which combines time-frequency analysis with surface electromyography (sEMG) signals obtained during ambulation. 3-bit pressure data is acquired using a pressure-sensitive mat, …

Slow Wave Structures Integrated With Ferro-Magnetic And Ferro-Electric Thin Films For Smart Rf Applications, B M Farid Rahman

Theses and Dissertations

Modern communications systems are following a common trend to increase the operational frequency, level of integration and number of frequency bands. Although 90-95% components in a cell phone are passives which take 80% of the total board area. High performance RF passive components play limited role and are desired towards this technological advancement. Slow wave structure is one of the most promising candidates to design compact RF and mm-Wave passive components. Slow wave structures are the specially designed transmission line realized by placing the alternate narrow and wide signal conductors in order to reduce the physical size of the components. …

Comprehensive Joint Time-Frequency Analysis Toward Condition Based Maintenance Regimes For Electrical And Mechanical Components, David Lee Coats

Theses and Dissertations

Based upon a framework of time-frequency analysis, we outline condition based maintenance (CBM), or maintenance only upon evidence of need, for both electrical and mechanical systems. We apply novel time-frequency cross-correlation metrics to helicopter drivetrain systems and electrical cables as remaining useful life assessments by non-destructive and non-invasive tests. In both cases, these metrics for health assessment provide a basis for diagnostic and prognostic analysis of underlying systems and components by performing accelerated condition tests on actual mechanical and electrical systems. We present novel time-frequency domain vibration analysis of a gearbox failure in an AH-64 Apache drivetrain testbed and quantify …

Advanced Digital Signal Processing Based Redefined Power Quality Indices, And Their Applications To Wind Power, Md Moinul Islam

Theses and Dissertations

This dissertation proposes a time-frequency distribution (TFD) based new method to redefine the power quality (PQ) indices for the assessment of PQ disturbances typically present in electric power systems. The redefined PQ indices are applied to various types of synthetic and real-world PQ disturbances in order to verify the efficacy and applicability of the proposed method. The case studies show that the proposed method provides actual results with respect to the existing TFD-based transient PQ indices, and provides much more accurate results than the traditional fast Fourier transform (FFT) based PQ indices under stationary and nonstationary PQ disturbances. In addition, …

Holographic-Based Leaky Wave Antennas And Phonon-Enhanced Waveguides For Infrared Applications, Franklin Muriuki Manene

Theses and Dissertations

This work contributes to critical requirements for antenna-coupled detection applications: 1) large capture cross section with design control of angular response and 2) long propagation lengths of complex signals. Antenna-coupled detectors for infrared applications provide appreciable capture cross sections while delivering signals to sub-wavelength-sized detectors. In this work, leaky-wave antennas are considered for the first time in the infrared spectrum. Design characterization of angular radiation patterns as well as polarization is presented. While leaky-wave antennas hold great promise for enhancing capture cross section, thus narrowing the field of view of the detector, there is a parallel need to preserve coherent …

An Optogenetic Brain-Machine Interface For Spatiotemporal Neuromodulation, Ryan Andrew Baumgartner

Theses and Dissertations

Direct neural stimulation has recently become a standard therapy for neurological disorders such as Parkinson's Disease, Essential Tremors, and Dystonia. Currently, deep brain electro-stimulation and neuro-pharmaceutical treatments are the dominant therapeutic options available to the public. As our understanding of brain function and neurological diseases improves, we are able to develop more advanced neuromodulation techniques. These methods could become viable treatment solutions for treating brain dysfunction. Optogenetics, first introduced by a research team led by Karl Deisseroth at Stanford University, has proved to be a versatile technique with remarkable potential to be used in treatments for brain disorders, dysfunction, and …

Improving Mri Surface Coil Decoupling To Reduce B1 Distortion, Christian K. Larson

Theses and Dissertations

As clinical MRI systems continue to advance, larger focus is being given to image

uniformity. Good image uniformity begins with generating uniform magnetic fields, which

are easily distorted by induced currents on receive-only surface coils. It has become an

industry standard to combat these induced currents by placing RF blocking networks on

surface coils. This paper explores the effect of blocking network impedance of phased array surface coils on B1 distortion. It has been found and verified, that traditional approaches for blocking network design in complex phased arrays can leave undesirable B1 distortions at 3 Tesla. The traditional approach of …

Measurement Based Statistical Model For Path Loss Prediction For Relaying Systems Operating In 1900 Mhz Band, Masoud Dao Hamid

Theses and Dissertations

Relays play important role in deployment of Long Term Evolution (LTE) and LTE-Advanced systems. They are used to enhance coverage, throughput and system capacity. The impact of the relay deployment on the network planning has to be modeled so that the above mentioned goals can be achieved. For successful modeling one needs to predict the path loss on the link between an eNodeB and a relay station. The review of literature shows that there is a general shortage of measured data to help empirical understanding of the propagation conditions in relay environment. This dissertation aims at developing empirical path loss …

A Novel Transport Based Model For Wire Media And Its Application To Scattering Problems, Ebrahim Forati

Theses and Dissertations

Artificially engineered materials, known as metamaterials, have attracted the interest of researchers because of the potential for novel applications. Effective modeling of metamaterials is a crucial step for analyzing and synthesizing devices. In this thesis, we focus on wire medium (both isotropic and uniaxial) and validate a novel transport based model for them.

Scattering problems involving wire media are computationally intensive due to the spatially dispersive nature of homogenized wire media. However, it will be shown that using the new model to solve scattering problems can simplify the calculations a great deal.

For scattering problems, an integro-differential equation based on …

Speech Perception In Reverberated Condition By Cochlear Implants, Moulesh Bhandary

Theses and Dissertations

Previous Studies for bilateral cochlear implants users examined cocktail -party setting under anechoic listening conditions. However in real world listeners always encounter problems of reverberation, which could significantly deteriorate speech intelligibility for all listeners, independent of their hearing status.

The object of this study is to investigate the effects of reverberation on the binaural benefits for speech recognition by bilateral cochlear-implant (CI) listeners.

Bilateral CI subject was tested under different reverberation conditions. IEEE recorded sentences from one male speaker mixed with either speech shaped noise (ssn), energy masking, or with 2 female competing takers (2fsn), informational masking, at different signal …

Analysis, Validation, And Improvement Of High-Resolution Wind Estimates From The Advanced Scatterometer (Ascat), Jeffrey Richard Blodgett

Theses and Dissertations

The standard L2B ocean wind product from the Advanced Scatterometer (ASCAT) is retrieved as a 25 km product on a 12.5 km grid. Ultra-high resolution (UHR) processing allows ASCAT wind retrieval on a high-resolution 1.25 km grid. Ideally, such a high-resolution sample grid provides wind information down to a 2.5 km scale, allowing better analysis of winds with high spatial variability such as those in near-coastal regions and storms. Though the wind field is sampled on a finer grid, the actual data resolution needs to be validated. This thesis provides an analysis and validation of ASCAT UHR wind estimates in …

B1 Mapping For Magnetic Resonance Imaging, Daniel Joseph Park

Theses and Dissertations

Magnetic Resonance Imaging (MRI) is a non-ionizing form of medical imaging which has practical uses in diagnosing, characterizing, and studying diseases in vivo. Current clinical practice utilizes a highly trained radiologist to view MR images and qualitatively diagnose, characterize, or study a disease. There is no easy way to compare qualitative data. That is why developing quantitative measures in MRI show promise. Quantitative measures of disease can be compared across a population, MRI sites, and over time. Osteoarthritis is one disease where those who have it may benefit from the development of quantitative MRI measures. Those benefits may include earlier …

Compact Antennas And Arrays For Unmanned Air Systems, James Arthur Eck

Theses and Dissertations

A simple and novel dual-CP printed antenna is modelled and measured. The patch antennais small and achieves a low axial ratio without quadrature feeding. The measured pattern showsaxial ratio pattern squinting over frequency. Possible methods of improving the individual element are discussed, as well as an array technique for improving the axial ratio bandwidth. Three endfire printed antenna structures are designed, analyzed, and compared. The comparison includes an analysis of costs of production for the antenna structures in addition to their performance parameters. This analysis concludes that cost of materials primarily reduces the size of antennas for a given gain …

Tincr: Integrating Custom Cad Tool Frameworks With The Xilinx Vivado Design Suite, Brad S. White

Theses and Dissertations

The field programmable gate array (FPGA) is appealing as a computational platform because of its ability to be repurposed for a number of different applications and its relatively low design cost. Traditionally, FPGA vendors provide a set of electronic design automation (EDA) tools to assist customers with the implementation of their designs. These tools are necessarily general purpose, and the resulting tool flow does not provide the user much in the way of customization. Frameworks such as RapidSmith and Torc allow for the creation of custom CAD tools that are able to target actual Xilinx FPGA devices. However, they are …

Developments In Lfm-Cw Sar For Uav Operation, Craig Lee Stringham

Theses and Dissertations

Opportunities to use synthetic aperture radar (SAR) in scientific studies and military operations are expanding with the development of small SAR systems that can be operated on small unmanned air vehicles (UAV)s. While the nimble nature of small UAVs make them an attractive platform for many reasons, small UAVs are also more prone to deviate from a linear course due autopilot errors and external forces such as turbulence and wind. Thus, motion compensation and improved processing algorithms are required to properly focus the SAR images. The work of this dissertation overcomes some of the challenges and addresses some of the …

A Solid-State Ion Detector For Use In Portable Mass Spectrometry, Sadek Salman Sabbah

Theses and Dissertations

Mass spectrometry has long been used as a scientific tool in a wide variety of applications. A portable mass spectrometer would make many of these applications faster and more efficient. One of the key components of a mass spectrometer is its ion detection system; to make a mass spectrometer portable, this system must be small and involve as few components as possible. Single ion detection has been achieved through several methods, nearly all of which are well-known and understood. These methods, however, often require bulky vacuum and/or cooling systems in order to achieve high sensitivity. An ion detection system that …

Novel On-Chip Applications Using Silicon Photonics, Rania Gamal

Theses and Dissertations

The emerging field of silicon photonics offers solutions to designing CMOScompatible optical devices. By taking advantage of the immense fabrication infrastructure offered by the silicon industry, it would be possible to design optical structures that are smaller, faster, less-power consuming and cheaper than traditional, non-silicon-based optical devices. In this dissertation, the design and performance testing of two novel silicon photonic structures are presented: 1) Silicon nanowire ridge waveguide for sensing applications at the optical transmission frequency. 2) Doped silicon plasmonic structures for negative-index, epsilon-near-zero and sensing applications at the mid-infrared. For the first design, silicon nanowires are arranged in a …

Towards A Dynamic View Of Genetic Networks: A Kalman Filtering Framework For Recovering Temporally-Rewiring Stable Networks From Undersampled Data, Jehandad Khan

Theses and Dissertations

It is widely accepted that cellular requirements and environmental conditions dictate the architecture of genetic regulatory networks. Nonetheless, the status quo in regulatory network modeling and analysis assumes an invariant network topology over time. We refocus on a dynamic perspective of genetic networks, one that can uncover substantial topological changes in network structure during biological processes such as developmental growth and cancer progression. We propose a novel outlook on the inference of time-varying genetic networks, from a limited number of noisy observations, by formulating the networks estimation as a target tracking problem. Assuming linear dynamics, we formulate a constrained Kalman …

Development Of An Integrated Network Visualization And Graph Analysis Tool For Biological Networks, David Carbonetta

Theses and Dissertations

There has been steady increase in the amount of molecular data generated by experiments and computational methods performed on biological networks. There is a growing need to obtain an insight into the organization and structure of the massive and complex biological networks formed by the interacting molecules. To that end, this work presents the development of an integrated network visualization and graph analysis plugin within the Cytoscape framework. The plugin is capable of computing and visualizing a comprehensive set of dyad, node, and graph level statistics. The evaluation of the plugin on a range of biological networks and its memory …

Advances In Sca And Rf-Dna Fingerprinting Through Enhanced Linear Regression Attacks And Application Of Random Forest Classifiers, Hiren J. Patel

Theses and Dissertations

Radio Frequency (RF) emissions from electronic devices expose security vulnerabilities that can be used by an attacker to extract otherwise unobtainable information. Two realms of study were investigated here, including the exploitation of 1) unintentional RF emissions in the field of Side Channel Analysis (SCA), and 2) intentional RF emissions from physical devices in the field of RF-Distinct Native Attribute (RF-DNA) fingerprinting. Statistical analysis on the linear model fit to measured SCA data in Linear Regression Attacks (LRA) improved performance, achieving 98% success rate for AES key-byte identification from unintentional emissions. However, the presence of non-Gaussian noise required the use …

Hyperfine Interactions In The Electron Paramagnetic Resonance Spectra Of Point Defects In Wide-Band-Gap Semiconductors, Eric M. Golden

Theses and Dissertations

The focus of this research was to acquire definitive experimental data on predominant point defects in three important wide-band-gap semiconductors. Hyperfine interactions in electron paramagnetic resonance spectra were used to characterize the neutral nitrogen acceptor in zinc oxide, to identify a silicon interstitial impurity in titanium dioxide, and to determine the electronic structure of the singly ionized sulfur vacancy in stannous hexathiohypodiphosphate (SPS). Research on the basic properties of these technologically important materials plays a crucial role in the development of advanced optical and electronic systems. Zinc oxide is an electro-optic material with the potential to produce high performance electronics …

Optimization Algorithms For Inference And Classification Of Genetic Profiles From Undersampled Measurements, Belhassen Bayar

Theses and Dissertations

In this thesis, we tackle three different problems, all related to optimization techniques for inference and classification of genetic profiles. First, we extend the deterministic Non-negative Matrix Factorization (NMF) framework to the probabilistic case (PNMF). We apply the PNMF algorithm to cluster and classify DNA microarrays data. The proposed PNMF is shown to outperform the deterministic NMF and the sparse NMF algorithms in clustering stability and classification accuracy. Second, we propose SMURC: Small-sample MUltivariate Regression with Covariance estimation. Specifically, we consider a high dimension low sample-size multivariate regression problem that accounts for correlation of the response variables. We show that, …

Digital Back End Development And Interference Mitigation Methods For Radio Telescopes With Phased-Array Feeds, Richard Allen Black

Theses and Dissertations

The Brigham Young University (BYU) Radio Astronomy group, in collaboration with Cornell University, the University of Massachusetts, and the National Radio Astronomy Observatory (NRAO), have in recent years developed and deployed PAF systems that demonstrated the advantages of PAFs for astronomy. However, these systems lacked the necessary bandwidth and acquisition times to be scientifically viable. This thesis outlines the development of a 20-MHz bandwidth system that can acquire for much longer periods of time and across much larger bandwidths than previous BYU systems. A report of the deployment of this system on the 305-meter reflector at the Arecibo Observatory in …

Tunable Graphene Chem-Fet And Graphene/Si Heterojunction Chemi-Diode Sensors, Amol Kumar Singh

Theses and Dissertations

Graphene, a two-dimensional material with very high charge carrier concentration, has drawn large research interest for sensing chemical species based upon charge exchange. Atomically thin 2-dimensional arrangement of carbon in hexagonal fashion in graphene, where each carbon atom is attached to 3 neighboring carbon atoms, and presence of π* and π bands imparts it many amazing properties. Some of these properties such as very high mobility, low 1/f and thermal noise, modulation of carrier concentration and Fermi level by electrical, optical, and chemical means, and very high surface to volume ratio make graphene very promising sensing material. In order to …