Engineering Commons^™

A Locomotion Control Algorithm For Robotic Linkage Systems, Jeffrey L. Dohner Dr.

Electrical and Computer Engineering ETDs

This dissertation describes the development of a control algorithm that transitions a robotic linkage system between stabilized states producing responsive locomotion. The developed algorithm is demonstrated using a simple robotic construction consisting of a few links with actuation and sensing at each joint. Numerical and experimental validation is presented. In this algorithm, transitioning excitations, called rhythms, are formulated using terminal state control solutions. Rhythms are constrained to be low order parameterized functions allowing for the optimal control problem to be replaced by a parametric optimization problem with a limited set of easily solved unknowns. This algorithm is developed and demonstrated …

Curricular Analytics In Higher Education, Ahmad Slim 3589498

Electrical and Computer Engineering ETDs

The dissertation addresses different aspects of student success in higher education. Numerous factors may impact a student's ability to succeed and ultimately graduate, including pre-university preparation, as well as the student support services provided by a university. However, even the best efforts to improve in these areas may fail if other institutional factors overwhelm their ability to facilitate student progress. This dissertation addresses this issue from the perspective of curriculum structure. The structural properties of individual curricula are studied, and the extent to which this structure impacts student progress is explored. The structure of curricula are studied using actual university …

Distributed And Scalable Video Analysis Architecture For Human Activity Recognition Using Cloud Services, Cody Wilson Eilar

Electrical and Computer Engineering ETDs

This thesis proposes an open-source, maintainable system for detecting human activity in large video datasets using scalable hardware architectures. The system is validated by detecting writing and typing activities that were collected as part of the Advancing Out of School Learning in Mathematics and Engineering (AOLME) project. The implementation of the system using Amazon Web Services (AWS) is shown to be both horizontally and vertically scalable. The software associated with the system was designed to be robust so as to facilitate reproducibility and extensibility for future research.

Scatterometry Of 50 Nm Half Pitch Features, Ruichao Zhu

Optical Science and Engineering ETDs

Metrology technologies are an essential adjunct to Integrated Circuit (I.C.) Semiconductor manufacturing. Scatterometry, an optical metrology, was chosen to measure 50 nm half pitch feature structures. A bread-board scatterometry system has been assembled to provide a non-contact, non-destructive, accurate and flexible measurement. A real-time, on-line scatterometry system has also been demonstrated and proven to provide a high throughput measurement.

Three different types of samples have been measured using the scatterometry setup. The wire-grid polarizer (WGP) sample has been made by Jet and Flash Nanoimprint Lithography with ~100 nm pitch and ~50 nm wide ~200 nm tall Al gratings on fused …

Compliant Culture Platforms With Independently Tunable Stiffness And Electrical/Optical Functionality, Nadeem Abdul

Electrical and Computer Engineering ETDs

Interfacing biological cells and solid-state devices is crucial in many applications, ranging from well-established fields, such as electrophisiology, to the newly developed areas of optogenetics and mechanobiology. Most biological cells are anchored to substrates with elastic modulus, E, in the range of ~1 to 100 kPa, the moduli of brain-tissue and osteoid, respectively. On the other hand, bulk semiconductor substrates have ~6 orders of magnitude higher elastic modulus. This large elastic mismatch between devices and cells natural microenvironments is an issue for bio-devices integration, as cells are highly sensitive to mechanical cues. Specifically, cells exert traction forces on their surroundings …

A Build System For Benchmarking And Comparison Of Competing System Implementations, Anthony J. Bentley

Electrical and Computer Engineering ETDs

When developing a hardware or software system, the problem at hand may lend itself to multiple solutions. During the implementation process for such systems, it can be helpful to prototype multiple versions that use distinct paradigms, and determine the efficiency of each according to some metric, such as execution time. This paper presents a portable, lightweight build system designed for easy benchmarking and verification of competing implementations of an algorithm. Also presented is a sample project that uses this system to compare the performance and correctness of CPU, GPU, and FPGA implementations of a signal recovery algorithm

Model Building And Security Analysis Of Puf-Based Authentication, Wenjie Che

Electrical and Computer Engineering ETDs

In the context of hardware systems, authentication refers to the process of confirming the identity and authenticity of chip, board and system components such as RFID tags, smart cards and remote sensors. The ability of physical unclonable functions (PUF) to provide bitstrings unique to each component can be leveraged as an authentication mechanism to detect tamper, impersonation and substitution of such components. However, authentication requires a strong PUF, i.e., one capable of producing a large, unique set of bits per device, and, unlike secret key generation for encryption, has additional challenges that relate to machine learning attacks, protocol attacks and …

Human Attention Detection Using Am-Fm Representations, Wenjing Shi

Electrical and Computer Engineering ETDs

Human activity detection from digital videos presents many challenges to the computer vision and image processing communities. Recently, many methods have been developed to detect human activities with varying degree of success. Yet, the general human activity detection problem remains very challenging, especially when the methods need to work “in the wild” (e.g., without having precise control over the imaging geometry). The thesis explores phase-based solutions for (i) detecting faces, (ii) back of the heads, (iii) joint detection of faces and back of the heads, and (iv) whether the head is looking to the left or the right, using standard …

Measurement And Analysis Of Iii-V & Ii-Vi Infrared Detectors: Radiometric, Noise Spectrum, And Radiation Tolerance Performance, Vincent M. Cowan

Nanoscience and Microsystems ETDs

Infrared (IR) hybrid detector arrays and discrete detectors operated in the space environment may be subjected to a variety of sources of natural radiation while in orbit. This means IR detectors intended for applications such as space-based intelligence, surveillance, and reconnaissance (ISR) or space-situational awareness (SSA) must not only have high performance (high quantum efficiency, h and low dark-current density, J_D, and preferably minimal 1/f noise content), but also their radiation tolerance or ability to withstand the effects of the radiation they would expect to encounter in space must be characterized and well understood. As the effects of …

Optimized Sizing And Placing Of Distributed Energy Resources (Ders) In An Island Microgrid Using Der-Cam, Bhuwan B. Bastola

Electrical and Computer Engineering ETDs

The electric grid at La Gomera, an island in the Canary archipelago, has been the subject of interest in optimized integration of Distributed Energy Resources (DERs) primarily because of high distribution losses and concerns about complying with emission regulations. Consequently, the utility that operates the island power system wishes to mitigate the problem with installation of renewable and distributed energy sources like PV and battery, which is the focus of this research.

Specifically, the focus of this thesis is to use Distributed Energy Resource - Customer Adoption Model (DER-CAM) to optimize the installation of PV and battery in terms of …

Searching Neuroimaging Biomarkers In Mental Disorders With Graph And Multimodal Fusion Analysis Of Functional Connectivity, Hao He

Electrical and Computer Engineering ETDs

Mental disorders such as schizophrenia (SZ), bipolar (BD), and major depression disorders (MDD) can cause severe symptoms and life disruption. They share some symptoms, which can pose a major clinical challenge to their differentiation. Objective biomarkers based on neuroimaging may help to improve diagnostic accuracy and facilitate optimal treatment for patients. Over the last decades, non-invasive in-vivo neuroimaging techniques such as magnetic resonance imaging (MRI) have been increasingly applied to measure structure and function in human brains. With functional MRI (fMRI) or structural MRI (sMRI), studies have identified neurophysiological deficits in patients’ brain from different perspective. Functional connectivity (FC) analysis …

Antimonide-Based Superlattice Membranes For Infrared Applications, Seyedeh Marziyeh Zamiri

Electrical and Computer Engineering ETDs

Semiconductor membranes offer an interesting materials and device development platform due to their ability to integrate dissimilar materials through a print, stamp and transfer process. There is a lot of interest in integrating antimonide based type-II superlattices (T2SL) onto inexpensive substrates, such as Si, to not only undertake fundamental studies into the optical, electronic and structural properties of the superlattices but also to fabricate wafer-level infrared (IR) photodetectors. An effective approach to transfer type-II superlattice membranes (T2SL-M) onto alternate substrates is based on membrane release from the native GaSb substrate followed by the transfer to a new host substrate. In …

Automatic Segmentation Of Coronal Holes In Solar Images And Solar Prediction Map Classification, Venkatesh Jatla

Electrical and Computer Engineering ETDs

Solar image analysis relies on the detection of coronal holes for predicting disruptions to earth’s magnetic field. The coronal holes act as sources of solar wind that can reach the earth. Thus, coronal holes are used in physical models for predicting the evolution of solar wind and its potential for interfering with the earth’s magnetic field. Due to inherent uncertainties in the physical models, there is a need for a classification system that can be used to select the physical models that best match the observed coronal holes. The physical model classification problem is decomposed into three subproblems. First, the …

Approaches For Capturing Time-Varying Functional Network Connectivity With Application To Normative Development And Mental Illness, Barnaly Rashid

Electrical and Computer Engineering ETDs

Since the beginning of medical science, the human brain has remained an unsolved puzzle; an illusive organ that controls everything- from breathing to heartbeats, from emotion to anger, and more. With the power of advanced neuroimaging techniques, scientists have now started to solve this nearly impossible puzzle, piece by piece. Over the past decade, various in vivo techniques, including functional magnetic resonance imaging (fMRI), have been increasingly used to understand brain functions. fMRI is extensively being used to facilitate the identification of various neuropsychological disorders such as schizophrenia (SZ), bipolar disorder (BP) and autism spectrum disorder (ASD). These disorders are …

Experimental Investigation Of Plasma Dynamics In Jets And Bubbles Using A Compact Coaxial Plasma Gun In A Background Magnetized Plasma, Yue Zhang

Electrical and Computer Engineering ETDs

Numerous solar and astrophysical observations of jet- and bubble-like plasma structures exhibit morphological similarities, suggesting that there may be common plasma physics at work in the formation and evolution processes of these structures at different system scales. The ideal magnetohydrodynamics (MHD) provide the necessary theoretical basis for employing laboratory experiments to investigate key physical processes in nonlinear astrophysical and solar systems, especially when magnetic fields are present.

A coaxial magnetized plasma gun has been designed, installed, and operated in the HelCat linear device at the University of New Mexico. In Region I, a current-driven plasma jet is formed. The plasma …

New Approaches For Estimating Hemispheric Lateralization From Resting State Fmri Data With Relationship To Age, Gender And Mental Disorders, Oktay Agcaoglu

Electrical and Computer Engineering ETDs

Lateralization is specialization of the brain hemispheres in certain tasks, such as language, mathematics, cognition and motor skills. It is one of the most queried topics related to the human brain. After the invention of modern medical imaging techniques including functional magnetic resonance imaging (fMRI), scientific research about the human brain, including lateralization, gained huge momentum. There have been a remarkable numbers of studies about lateralization and most of these studies focused on investigating which part of the brain dominates in which tasks. However, there have been very few lateralization studies on brain intrinsic activity, i.e., resting state activity where …

Rain Attenuation Effects On Signal Propagation At W/V-Band Frequencies, Nadine Daoud

Electrical and Computer Engineering ETDs

The current frequency spectrum congestion in space is begging for the exploration and utilization of a new range of frequencies. The W/V-band Terrestrial Link Experiment (WTLE) project run jointly by AFRL, NASA and the University of New Mexico, focuses on using higher frequencies for satellite communications, more precisely, at 72 GHz and 84 GHz.

In this thesis, the rain effect on the propagating signal is studied. First, instantaneous comparisons between the experiment and two different models, the ITU-R and the Siva-Mello, is presented. Second, the WTLE link was analyzed statistically over a period of approximately 10 months, and the ITU-R …

High Power Optically Pumped Semiconductor Lasers For Sodium Guidestar Applications, Shawn W. Hackett

Optical Science and Engineering ETDs

Optically pumped semiconductor lasers (OPSLs) are shown to provide a much more compact and less expensive source for illumination of the sodium layer of the mesosphere for use as a sodium laser guidestar via single and two photon excitation schemes. This represents a revolution in laser guidestar technology as the cost, size, and power requirements for a laser guidestar system are shown to have been decreased by an order of magnitude with guidestar performance shown to be similar to previous sources. Sodium laser guidestar sources for broadband simultaneous illumination of multiple lines are developed and simulated. Simulations are then compared …

Fabrication Of Hybrid Optical Electrical Platforms For Potential Applications In Neuromodulation, Aneesha Kondapi

Electrical and Computer Engineering ETDs

State-of-the art neuromodulators are bulky, and they are mostly fabricated on rigid substrates. Furthermore, they are not provided with a feedback control loop re- sulting in undesired off-target effects. This thesis paves the way for fabrication of lightweight neural interfaces with the capability to implement closed-loop controlled neuromodulation down to a single-cell resolution. In this work, an approach based on hybrid optical-electrical devices to implement neuromodulation is presented. The rationale of this choice, design illustration, fabrication and characterization is discussed. In addition, a proof-of-concept neural interface is illustrated. Specif- ically, hybrid optical-electrical devices are developed based on inorganic thin films, …

Avalanche Isfet Sensing Chip For Dna Sequencing, Mohammad Uzzal

Electrical and Computer Engineering ETDs

DNA sequencing is a fundamental tool for biological science, aimed primarily at uncovering the genetic contributions to diseases. The first Human DNA sequence, which employed conventional fluorescent-based Sanger Sequencing method, took many years to complete at a cost of over three billion dollars. In one survey, it shows that Human Genome Project (HGP) had generated more than $67 billion in U.S. economic output, $20 billion in personal income for Americans and 310 thousand jobs in USA, only during year 2010. The HGP has increased the need for high-throughput, low cost, fast, accurate and inexpensive DNA sequence technique. This demand has …

Fault Resilient And Reconfigurable Power Management Using Photovoltaic Integrated With Cmos Switches, Rakeshkumar Mahto

Electrical and Computer Engineering ETDs

A Photovoltaic (PV) cell is a device which converts light incident upon it to electric current. The push for green energy due to global warming and diminution of fossil fuels opens up a huge market for PV cells. Hence, a lot of interest is being garnered for using PV cells for various applications. However, a PV module's performance degrades due to many anomalies such as failure of individual PV cell within a module, the opening of interconnection, a short circuit in the connection, failure of bypass diode, failure in voltage regulator or partial shading. To some extent all of these …

Statistical Behavior Of Distributed Microgrids With Cascading Model Predictive Control, Yasser Yasaei

Electrical and Computer Engineering ETDs

The problem of integration of distributed energy resources into the grid is addressed in this study. The main objective is to deploy such resources as an alternative for conventional resources in a power system, and to increase renewable resources share in the generationmix. Distributed energy resources in general come with small capacities, and may have an intermittent nature. The former characteristic limits their impact on large scale grid applications, while the latter characteristic can induce serious stability problems in the system. As the first step, an appropriate model is developed to mathematically describe the behavior of such resources and to …

Numerical Modeling Of Nonlinear Mode Interaction In Semiconductor Lasers And Amplifiers To Generate Slow/Fast Light, Hemashilpa Kalagara

Electrical and Computer Engineering ETDs

The nonlinear interaction (NLI) between modes in a semiconductor laser or amplifier is one of the techniques to obtain slow light (ng >> 1), fast light (-1 < ng < 1), phase conjugated reflection (also known as backward light (ng < 0)) and supercontinuum emission (also known as critically anomalous dispersion (ng = 0)), where ng is the group index. In the nonlinear interaction (NLI) mechanism, the interaction between a driving wave (mode) which is of sufficiently high intensity, and a probe wave (mode) results in modification of complex permittivity of the probe wave, if the frequency detuning between the two waves falls into the spectral range of parametric interaction. Consequently, in the vicinity of a strong driving wave (mode), the optical parameters such as the phase index, group index, linewidth, and the gain of a neighboring probe (weak) wave are strongly perturbed. The unusual perturbation of group index leads to slow light, fast light and backward propagating light depending on the frequency detuning between the two waves. Fast light can have important applications in interferometry, to make very sensitive interferometric sensors for detection of nano displacement, ultra-low vibration, rotation rate and even very weak gravitational waves. The slope sensitivity of an active integrated ring laser gyro (RLG) is directly proportional to the size of the ring and inversely proportional to the group index of the medium filling the cavity. By reducing ng in the nonlinear regime of laser operation, slope sensitivity can be improved by manifolds without having to increase the size of the gyro, which will lead to monolithic integration. In this dissertation work, the numerical modeling and simulation of NLI in semiconductor ridge waveguide (RWG) lasers is performed and perturbations of phase index, group index, gain, linewidth are calculated. The modeling is based on theory of nonlinear interaction of waves' developed for plane waves and is applied to RWG lasers. The RWG laser structures are based on GaN/InGaN, GaAs/AlGaAs, InGaAs/GaAs/AlGaAs, InGaAsP/InP material systems, to cover the most important spectral range of semiconductor lasers starting from λ = 0.4 μm to λ = 1.55 μm, respectively. The photonic design software RSoft's FemSIM that uses finite element method is used for design and modeling of NLI in RWG and calculation of effective phase index. The induced dispersion and effective group index ng are then calculated by differentiation of the effective phase index of guided probe wave over the optical frequency. The calculations indicate that the magnitude of NLI depends on the driving wave intensity, frequency detuning between driving and probe waves, lifetime of carriers in the laser system, optical confinement factor, driving wave wavelength and linewidth broadening factor of the laser structure. An important result of this work is observation of frequency points where ng passes zero line, known as the points of critically anomalous dispersion (CAD). In the spectral vicinity of CAD points, superluminal group velocity is observed, which can be used for improving the sensitivity of ring laser gyros and other interferometric sensors. In this dissertation, we established possibility of superluminal behavior (-1 < ng < 1) through NLI in all of the above mentioned RWG laser structures, and obtained the conditions necessary to observe this behavior. Also, the CAD frequencies are plotted by varying the driving wave intensities, where the data form a closed loop. The closing of the loop is due to suppression of NLI with an increase in driving wave intensity; at high intensities, the stimulated recombination rate increases, leading to an increase in overall relaxation rate, which in turn decreases the NLI. The CAD loops are calculated for all the RWG lasers mentioned above. The CAD loops provide information on lower and upper threshold intensity of the driving wave, and on frequency detuning between the driving and probe waves for observation of superluminal group velocity. Another important result is that the perturbed linewidth increases infinitely at the CAD point, leading to supercontinuum emission or white light, which can be exploited for very broadband laser emission applications. We also fitted our numerically calculated perturbed delay and advance due to NLI with the experimental data of perturbed delay and advance of an optical pulse in a semiconductor optical amplifier based on InGaAsP/InP, and identified the CAD point for the very first time.'

A Ridge-Fed Conical Horn Antenna For Small Satellites, Arjun Gupta

Electrical and Computer Engineering ETDs

The increased popularity of small satellites such as CubeSats as an alternative vehicle for efficient and low cost space exploration has revolutionized the space research industry. The small physical size and other constraints owing to outer space applications has presented a myriad of exciting opportunities for antenna engineers to come up with alternative solutions to meet the ever evolving needs of the CubeSat applications. The advancement of technology has enabled small satellites to carry out sophisticated missions such as space weather monitoring, space telescopes, imaging and relaying of information from distant satellites. Advanced applications require a high speed downlink with …