Engineering Commons^™

Optical Angular Scatterometry: In-Line Approach For Roll-2-Roll And Nano-Imprint Fabrication Systems, Juan Jose Faria-Briceno

Electrical and Computer Engineering ETDs

As critical dimensions continue to shrink and structures become more complex, metrology processes are challenging to implement during in-line nanomanufacturing. Non-destructive, non-contact, and high-speed conditions are required to achieve proper metrology processes during in-line manufacturing. Optical scatterometry is a nanoscale metrology tool widely used in integrated circuit manufacturing for characterization and quality control. However, most applications of optical scatterometry operate off-line. A high-speed, in-line, non-contact, non-destructive scatterometry angular system has been demonstrated in this work to scan pattern surfaces during real-time nano-fabrication.

Our system has demonstrated scanning capabilities using flat, 1D and 2D complex structures. The flat surface samples consist …

Measurement Of Photoionization Rates In Air, Justin K. Smith

Electrical and Computer Engineering ETDs

The ionization of gas molecules from the absorption of photons produced in different parts of a discharge is an important process in the development of streamers. Photoionization rates are essential in the propagation of streamers and are therefore important in simulations of computational codes. Although streamers are widely used in computational codes, there is a limited data set on the experiments measuring photoionization rates in gases. Usually, the photoionization rate data used in computational codes comes from a single source and the validity of this data combined with the photoionization model has been questionable. It is postulated there is a …

Software Design For Probabilistic Safety: Stochastic Reachability And Circadian Control, Joseph D. Gleason

Electrical and Computer Engineering ETDs

Stochastic reachability is an important verification tool that provides probabilistic assurances of safety in a variety of contexts. In engineered systems, safety may be synonymous with the ability of the system to avoid "bad" constraints on the state space, that constitute collision, departure from a flight envelope, or other undesirable phenomenon. In biomedical systems, assurance of safety (such as the mandate to ``do no harm'') are considerably complicated by the fact that there is a lack of physics-driven models, extensive signal processing is needed to capture the underlying state of the system, and the stochasticity inherent to the system may …

Vision-Based Autonomous Tracking Of A Non-Cooperative Mobile Robot By A Low-Cost Quadrotor Vehicle, Cheikhna Ahmed Tidiane Sy

Electrical and Computer Engineering ETDs

The goal of this thesis is the detection and tracking of a ground vehicle, in particular a car-like robot, by a quadrotor. The first challenge to address in any pursuit or tracking scenario is the detection and unique identification of the target. From this first challenge, comes the need to precisely localize the target in a coordinate system that is common to the tracking and tracked vehicles. In most real-life scenarios, the tracked vehicle does not directly communicate information such as its position to the tracking one. From this fact, arises a non-cooperative constraint problem. The autonomous tracking aspect of …

Validation Of Gaseous Absorption & Cloud Attenuation Models Utilizing A 72 Ghz Terrestrial Link, Ralph Lyndon Gesner

Electrical and Computer Engineering ETDs

Interest in the W & V-bands of the radio frequency (RF) spectrum has become steadily more desirable for system designers due to the ever increasing need for greater communication bandwidths and higher data rates. The 40 GHZ to 110 GHz range that constitutes the W & V-bands provide a unique solution to both of these current demands by providing a bandwidth nearly double that of all current RF frequencies in use. To date, this range has only been used for point to point satellite and short link communications meaning these bands have remained largely unexplored and undeveloped.

To capitalize on …

Experimental Testing Of A 3d-Printed Metamaterial Slow Wave Structure For High Power Microwave Generation, Antonio B. De Alleluia

Electrical and Computer Engineering ETDs

A metamaterial (MTM) high power microwave (HPM) vacuum electron device (VED) was developed using 3D printing technology. The specific geometric pattern of the source can produce both negative permittivity and permeability to interact with a relativistic electron beam. The electron beam is generated using a pulsed electron accelerator with a maximum energy of 700 keV and lasting approximately 16 ns. The design of this novel VED consists of a circular waveguide loaded with complementary split-ring resonators in a linear periodic arrangement in which the relativistic beam travels guided by a magnetic field. The electrons interact with the MTM producing electromagnetic …

Demand Response Management In Smart Grid Networks: A Two-Stage Game-Theoretic Learning-Based Approach, Pavlos Athanasios Apostolopoulos

Electrical and Computer Engineering ETDs

In this diploma thesis, the combined problem of power company selection and Demand Response Management in a Smart Grid Network consisting of multiple power companies and multiple customers is studied via adopting a distributed learning and game-theoretic technique. Each power company is characterized by its reputation and competitiveness. The customers who act as learning automata select the most appropriate power company to be served, in terms of price and electricity needs’ fulfillment, via a distributed learning based mechanism. Given customers' power company selection, the Demand Response Management problem is formulated as a two-stage game theoretic optimization framework, where at the …

Study Of Distributed Versus Compressed Layouts For Physically Unclonable Functions, Joshua Trujillo

Electrical and Computer Engineering ETDs

Society continues to depend on electronics for everything from smart systems in our homes to cellphones and tablets, which are more powerful today than many desktop computers that are still in use [1]. With increased consumption of these electronic products comes an increase in problems, such as counterfeit integrated circuits being sold as genuine integrated circuits. This is just one of many problems that corporations and end users are having to deal with in this digital age.

Software security has been accepted as a problem by both the media and general public, but only recently has hardware security begun to …

Satisfaction-Aware Data Offloading In Surveillance Systems, Marcos Paul Torres

Electrical and Computer Engineering ETDs

In this thesis, exploiting Fully Autonomous Aerial Systems' (FAAS) and Mobile Edge Computing (MEC) servers' computing capabilities to introduce a novel data offloading framework to support the energy and time-efficient video processing in surveillance systems based on satisfaction games. A surveillance system is introduced consisting of Areas of Interest (AoIs), where a MEC server is associated with each AoI, and a FAAS is flying above the AoIs to support the IP cameras' computing demands. Each IP camera adopts a utility function capturing its Quality of Service (QoS) considering the experienced time and energy overhead to offload and process remotely or …

Artificial Intelligence Empowered Uavs Data Offloading In Mobile Edge Computing, Nicholas Alexander Kemp

Electrical and Computer Engineering ETDs

The advances introduced by Unmanned Aerial Vehicles (UAVs) are manifold and have paved the path for the full integration of UAVs, as intelligent objects, into the Internet of Things (IoT). This paper brings artificial intelligence into the UAVs data offloading process in a multi-server Mobile Edge Computing (MEC) environment, by adopting principles and concepts from game theory and reinforcement learning. Initially, the autonomous MEC server selection for partial data offloading is performed by the UAVs, based on the theory of the stochastic learning automata. A non-cooperative game among the UAVs is then formulated to determine the UAVs' data to be …

Using Uncertainty To Interpret Supervised Machine Learning Predictions, Michael C. Darling

Electrical and Computer Engineering ETDs

Traditionally, machine learning models are assessed using methods that estimate an average performance against samples drawn from a particular distribution. Examples include the use of cross-validation or hold0out to estimate classification error, F-score, precision, and recall.

While these measures provide valuable information, they do not tell us a model's certainty relative to particular regions of the input space. Typically there are regions where the model can differentiate the classes with certainty, and regions where the model is much less certain about its predictions.

In this dissertation we explore numerous approaches for quantifying uncertainty in the individual predictions made by supervised …

A Machine Learning Based Framework For Load Forecasting And Optimal Operation Of Power Systems With Distributed Generation, Tairen Chen

Electrical and Computer Engineering ETDs

The fast development and wide utilization of distributed generations (DGs), such as Photovoltaic panels and wind turbines, provide environmentally friendly renewable energy. However, inappropriate operation, sizing, and placement of DGs could increase the power losses and reduce the stability of the power network. Load forecasting is critical to the electrical utilities to schedule power generation and distribution. In this dissertation, a framework is proposed for load forecasting and optimal operation of power system with DGs in the distribution feeder-level.

In the first part, a nonparametric method, the Bayesian Additive Regression Trees (BART), is introduced for day-ahead peak load forecasting. The …

Pixelated Gasb Membranes For Photovoltaics: Fabrication And Structure-Property Relationships, Vijay Saradhi Mangu

Electrical and Computer Engineering ETDs

In this thesis, I present a reliable and efficient approach to heterogeneous integration of single-crystalline GaSb semiconductors with highly mismatched materials. The mismatch may refer to the crystalline structure and the thermal expansion coefficient of single-crystalline GaSb and the other materials of interest. The strategy of hetero-integration relies on epitaxial lift-off. This approach prevents the formation of extended structural defects that are detrimental to the performance of optoelectronic devices and preserves GaSb growth substrates for potential reuse.

Within my research work, I have overcome some outstanding challenges of epitaxial lift-off of GaSb, and I have demonstrated the operation of single-crystalline …

Identification Of The Corona Point In Point-To-Plane Geometries In Atmospheric Air, Leonardo Rossetti

Electrical and Computer Engineering ETDs

The minimum sustaining electric field for streamer propagation is directly correlated to the minimum electric field at the corona point. Corona is a product of non-uniform electric fields; the onset of corona occurs before electrical breakdown. As electric fields become increasingly uniform the required field strength to produce corona is increased as well. The field uniformity can be increased until a critical point in which electrical breakdown coincides with the onset of a positive corona, this is known as the corona point.

An experimental setup with a point to plane configuration allows precise changes in electric field uniformity, by gradually …

Design And Fabrication Of Peel-Off And Stick Antennas, Jayakrishnan Vijayamohanan

Electrical and Computer Engineering ETDs

Antennas on multiple platforms with the capability to be reused is a novel concept in antenna technologies. This thesis explores the idea of such a flexible antenna that can be stuck on any surface using certain adhesives and be peeled off for reuse for a different purpose. This thesis specifically focuses on the application of being used on small Unmanned Aircraft Systems (sUAVs). Three basic designs are fabricated and investigated. One of them is a reconfigurable meandering monopole, consisting of a PIN diode which resonates at two different frequencies depending on the applied external voltage. A challenge that is addressed …

The Importance Of The Instantaneous Phase In Detecting Faces With Convolutional Neural Networks, Luis Armando Sanchez Tapia

Electrical and Computer Engineering ETDs

Convolutional Neural Networks (CNN) have provided new and accurate methods for processing digital images and videos. Yet, training CNNs is extremely demanding in terms of computational resources. Also, for simple applications, the standard use of transfer learning also tends to require far more resources than what may be needed. Furthermore, the final systems tend to operate as black boxes that are difficult to interpret.

The current thesis considers the problem of detecting faces from the AOLME video dataset. The AOLME dataset consists of a large video collection of group interactions that are recorded in unconstrained classroom environments. For the thesis, …

Verification Of Stochastic Reach-Avoid Using Rkhs Embeddings, Adam J. Thorpe

Electrical and Computer Engineering ETDs

A solution to the terminal-hitting and first-hitting stochastic reach-avoid problem for a Markov control process is presented. This solution takes advantage of a nonparametric representation of the stochastic kernel as a conditional distribution embedding within a reproducing kernel Hilbert space (RKHS). Because the disturbance is modeled as a data-driven stochastic process, this representation avoids intractable integrals in the dynamic recursion of the reach-avoid problem since the expectations can be calculated as an inner product within the RKHS. An example using a high-dimensional chain of integrators is presented, as well as for Clohessy-Wiltshire-Hill (CWH) dynamics.

Iii-V Nbn Focal Plane Arrays: Radiometric Characteristics As A Function Of Detector Cutoff Wavelength, Victor Darie Pepel

Electrical and Computer Engineering ETDs

Summarized here are the measured radiometric characteristics of three Infrared III-V InAsSb/AlAsSb/InAsSb-based nBn focal plane arrays (FPAs) in the SWIR to MWIR range with cutoff wavelengths of 2.85 µm, 3.3 µm and 4.2 µm at the nominal operating temperature of 150 K. Herein referred to by their respective cutoff wavelengths, the nBn detectors are characterized across the temperature range of 130 K to 180 K. The optical response and noise characteristics are examined as a function of cutoff wavelength, and a comparison of dark current density is made to HgTeCd photodiodes using the Rule ‘07 heuristic.

The 2.85 µm, 3.3 …

Large Scale Electronic Health Record Data And Echocardiography Video Analysis For Mortality Risk Prediction, Alvaro Emilio Ulloa Cerna

Electrical and Computer Engineering ETDs

Electronic health records contain the clinical history of patients. The enormous potential for discovery in such a rich dataset is hampered by their complexity. We hypothesize that machine learning models trained on EHR data can predict future clinical events significantly better than current models. We analyze an EHR database of 594,862 Echocardiography studies from 272,280 unique patients with both unsupervised and supervised machine learning techniques.

In the unsupervised approach, we first develop a simulation framework to evaluate a family of different clustering pipelines. We apply the optimized approach to 41,645 patients with heart failure without providing any survival information to …

Nonpolar Gan-Based Vcsels With Lattice-Matched Nanoporous Distributed Bragg Reflector Mirrors, Saadat M. Mishkat-Ul-Masabih

Electrical and Computer Engineering ETDs

Wide-bandgap optoelectronic devices have undergone significant advancements with the advent of commercial light-emitting diodes and edge-emitting lasers in the violet-blue spectral region. They are now ubiquitous in several lighting, communication, data storage, display, and sensing applications. Among the III-nitride emitters, vertical-cavity surface-emitting lasers (VCSELs) have attracted significant attention in recent years due to their inherent advantages over edge-emitting lasers. The small active volume enables single-mode operation with low threshold currents and high modulation bandwidths. Their surface-normal device geometry is conducive to the cost-effective formation of high-density 2D arrays while simplifying on-chip wafer testing. Furthermore, the low beam divergence and circular …

Non-Invasive Beam Monitoring With Harmonic Cavities, Brock F. Roberts

Electrical and Computer Engineering ETDs

NON INVASIVE BEAM MONITORING WITH HARMONIC CAVITIES

by

Brock Franklin Roberts

B.S PHYSICS, UNIVERSITY OF CALIFORNIA DAVIS, 1992

DOCTOR OF PHILOSOPHY IN ELECTRICAL ENGINEERING

UNIVERSITY OF NEW MEXICO, 2019

ABSTRACT

A cavity designed to have multiple harmonic TM0N0 modes can be used to accurately measure the longitudinal profile of a bunched charged particle beam passing through its bore, non-invasively, and in real time.

Multi-harmonic TM0N0 cavities were designed, constructed, and beamline tested in a variety of experiments at the Thomas Jefferson National Accelerator Facility (TJNAF or Jlab). Measurements with a sampling oscilloscope provided signals that resemble the profile of electron …

Transport In Mid-Wavelength Infrared (Mwir) P- And N-Type Inassb And Inas/Inassb Type-Ii Strained Layer Superlattices (T2sls) For Infrared Detection, Lilian K. Casias

Electrical and Computer Engineering ETDs

In order to tackle vertical transport, lateral transport must be better understood. There are added challenges to determining the lateral bulk carrier concentration in narrow bandgap materials due to the potential for electron accumulation at the surface of the material and at its interface with the layer grown directly below it. Electron accumulation layers form high conductance electron channels that can dominate both resistivity and Hall-Effect transport measurements. Therefore, to correctly determine the lateral bulk concentration and mobility, temperature- and magnetic-field-dependent transport measurements in conjunction with Multi-Carrier Fit (MCF) analysis were utilized on a series of p-doped InAs_{0.91 …}

Detection And Classification Of Vibrating Objects In Sar Images, Francisco German Perez Venegas

Electrical and Computer Engineering ETDs

The vibratory response of buildings and machines contains key information that can be exploited to infer their operating conditions and to diagnose failures. Furthermore, since vibration signatures observed from the exterior surfaces of structures are intrinsically linked to the type of machinery operating inside of them, the ability to monitor vibrations remotely can enable the detection and identification of the machinery.

This dissertation focuses on developing novel techniques for the detection and M-ary classification of vibrating objects in SAR images. The work performed in this dissertation is conducted around three central claims. First, the non-linear transformation that the micro-Doppler return …

Strong Light Matter Interactions At The Nanoscale: Formation Of Polaritons In Hybrid Dielectric Metasurfaces, Huck Kootenai Green

Electrical and Computer Engineering ETDs

Study and control of light matter interactions at the nanoscale is an extremely active topic of research as it can create intriguing new opportunities for sensing, optoelectronics, nonlinear optics, and other nanophotonic devices. Various platforms have been investigated to study light-matter interactions at the nanoscale. The most recent explorations in research come from one platform, metasurfaces – planar equivalents of three dimensional metamaterials. Previous studies of strong light matter interaction have been demonstrated on metallic metasurfaces. However, there are little experiments demonstrating strong light-matter interaction in all dielectric metasurfaces. We present a study demonstrating strong light-matter interactions in a hybrid …

Design And Implementation Of A 72 & 84 Ghz Terrestrial Propagation Experiment; Exploitation Of Nexrad Data To Statistically Estimate Rain Attenuation At 72 Ghz, Nicholas Pawel Tarasenko

Electrical and Computer Engineering ETDs

The wireless communication sector is rapidly approaching network capacities as a direct result of increasing mobile broadband data demands. In response, the Federal Communications Commission allocated 71-76 GHz “V-band” and 81-86 GHz “W-band” for terrestrial and satellite broadcasting services. Movement by the telecommunication industry towards W/V-band operations is encumbered by a lack of validated and verified propagation models, specifically models to predict attenuation due to rain. Additionally, there is insufficient data available at W/V-bands to develop or test propagation models. The first aim of this study was the successful installation and operation of a terrestrial link to collect propagation data …

Optimizing Interconnectivity Among Networks Under Attacks, Pankaz Das

Electrical and Computer Engineering ETDs

Networks may need to be interconnected for various reasons such as inter-organizational communication, redundant connectivity, increasing data-rate and minimizing delay or packet-loss, etc. However, the trustworthiness of an added interconnection link cannot be taken for granted due to the presence of attackers who may compromise the security of an interconnected network by intercepting the interconnections. Namely, an intercepted interconnection link may not be secured due to the data manipulations by attackers. In the first part of this dissertation, the number of interconnections between the two networks is optimized for maximizing the data-rate and minimizing the packet-loss under the threat of …