Engineering Commons^™

Resiliency Of Levee-Protected Power Networks To Flooding In A Changing Climate Integrating Environmental Justice, Seyed Saeed Miraee-Ashtiani

Theses and Dissertations

Electric power system (EPS) is an integral part of infrastructure systems. Ensuring its resiliency to extreme weather events and natural hazards is crucial to protect the safety, economy and public health. Recorded and projected data show an increase in the frequency and severity of extreme weather events and natural hazards attributed to a changing climate. It is critical to ensure the integrity of the aging infrastructure systems and to promote environmental justice by shrinking the energy-equity gap to lower power outages in disadvantaged communities.

An important aspect is the resiliency interdependency of EPS to other critical infrastructure systems, an aspect …

Comparing Importance Of Knowledge And Professional Skill Areas For Engineering Programming Utilizing A Two Group Delphi Survey, John F. Hutton

Theses and Dissertations

All engineering careers require some level of programming proficiency. However, beginning programming classes are challenging for many students. Difficulties have been well-documented and contribute to high drop-out rates which prevent students from pursuing engineering. While many approaches have been tried to improve the performance of students and reduce the dropout rate, continued work is needed. This research seeks to re-examine what items are critical for programming education and how those might inform what is taught in introductory programming classes (CS1). Following trends coming from accreditation and academic boards on the importance of professional skills, we desire to rank knowledge and …

High Power, Medium Frequency, And Medium Voltage Transformer Design And Implementation, Ahmad El Shafei

Theses and Dissertations

Many industrial applications that require high-power and high-voltage DC-DC conversion are emerging. Space-borne and off-shore wind farms, fleet fast electric vehicle charging stations, large data centers, and smart distribution systems are among the applications. Solid State Transformer (SST) is a promising concept for addressing these emerging applications. It replaces the traditional Low Frequency Transformer (LFT) while offering many advanced features such as VAR compensation, voltage regulation, fault isolation, and DC connectivity. Many technical challenges related to high voltage stress, efficiency, reliability, protection, and insulation must be addressed before the technology is ready for commercial deployment. Among the major challenges in …

A Voice And Facial Recognition System To Protect Students From Being Forgotten Inside School Buses In The Kingdom Of Saudi Arabia, Ibrahim Alferaih

Theses and Dissertations

In this research, we discuss the situation of students in the three to eight year old age group. Every day in the Kingdom of Saudi Arabia during school days, more than 1,000,000 students are transported throughout the country by more than 15,000 school buses. Everything is dependent on the human element. During school transportation around the world, many children are forgotten inside the school bus and with many of them eventually going missing or even dying. The bus driver is usually busy and tired due to the focus on the road, which may make him lose focus on those on …

Safety-Aware Longitudinal And Lateral Control Of Autonomous Vehicles, Randy Guadalupe Chapa

Theses and Dissertations

Safety is undoubtedly the most critical design requirement regarding autonomous vehicle controllers. This research considers an autonomous vehicle to keep a desired distance from the leader vehicle, as well as stay centered within the lane. To achieve this, the lateral control problem and the combined longitudinal and lateral control problem were studied. Adaptive control laws were proposed with the aid of the backstepping technique and the barrier function technique. Simulation was done to verify the effectiveness of the proposed control laws.

Ambient Air-Processed Cspbi3-Based Perovskite Solar Cell Via Semi-Sputtering Deposition And Numerical Studies Of Cs3sb2i9-Based Perovskite Solar Cell, Shamik Datta

Theses and Dissertations

Commercialization of Perovskite solar cells as a clean energy source can augment the reduction of carbon footprint. CsPbI3, a well-known perovskite material, has been synthesized in ambient air and high-humidity conditions and utilized as the active layer in a perovskite solar cell. The rest of the solar cell layers have been sputter-deposited. This solar cell with a p-i-n configuration ITO/NiOx/CsPbI3/ZnO/Au exhibited a champion efficiency of 3.7%. Nonetheless, lead incorporation in the conventional Pb-cation-based perovskites poses an environmental threat. The physical proximity of living organisms to lead point sources exhibits a wide spectrum of negative consequences. In this study, we have …

Modeling And Validation Of Common-Mode Emission In Silicon Carbide Based Voltage Source Converters, Tianchen Li

Theses and Dissertations

Electromagnetic compatibility (EMC) issues have become one of the most difficult challenges in power converter designs. With the invention of wide bandgap (WBG) power semiconductors such as silicon carbide (SiC) and gallium nitride (GaN) power MOSFETs, the power converter designs are provided with the potential to be significantly more power dense than older generation converters using silicone IGBTs. However, the majority of spectral contents of the switching waveforms are moved from the very-low-frequency (VLF, 3 kHz to 30 kHz) range to low-frequency and up to the very-high-frequency (VHF, 30 MHz to 300 MHz) range. Moreover, due to the design traits …

Fostering Collaboration In Emerging Three-Tiered Spectrum Markets, Anindo Mahmood

Theses and Dissertations

Ensuring optimum spectral efficiency is a critical requirement for current wireless networks to cope with the ever-growing flow of wireless data traffic, using limited spectral resources. As such, spectrum sharing, which allows different grades of users, as well as multiple networking standards to co-exist and utilize in the same frequency band, has become a topic of great intrigue. Due to the inherent advantages of these schemes, the US government has opened up vast amounts of federal spectrum that supports spectrum sharing. The Citizens Broadband Radio Service (CBRS) proposed by the Federal Communications Commission (FCC) is one of them. A tiered …

Simncore: Multilevel Cache Memory Design Simulator For Manycore System, Provashish Roy

Theses and Dissertations

The current trend in a processor design has moved from multicore to manycore (tens to hundreds, or more cores) to support more computational power based on parallelism. One of challenges is how to handle such large number of cores’ data in cache memories through an efficient inter-core communication and cache coherence. To meet the demand, this paper presents a manycore cache memory simulator for research and education purposes. The proposed simulator, called as SIMNCORE, is to design and evaluate various multi-level, such as L1 and L2, cache memories for manycore processing. The SIMNCORE will implement various trace files collected from …

Deep Learning Approach To Speech Recognition: A Signal Extractor & Producer For Artificial General Intelligence, Ahmad Zuhair S. Hasanain

Theses and Dissertations

The efficient use of a communication bandwidth starts with the data source. The features of the speech signals can be extracted and reconstructed to lower the Internet traffic of the acoustic artificial agents and to increase the quality of the automatic speech recognition systems. The Speech Quefrency Transform (SQT) is hereby introduced in the work to enrich the communication space between the artificial agents and mankind. We describe the motivation, methodology, and deep learning approach in detail as we apply the SQT technology to several applications: sharp pitch track extraction, real-time speech communications, and emotion recognition. The results were excellent. …

Investigation Of Polymer Nanocomposites With Silicon Dioxide Fillers As Helium Cooled High-Temperature Superconducting Cable Dielectrics, Jordan Thomas Cook

Theses and Dissertations

In this thesis, three polymer nanocomposite configurations are fabricated for investigation as dielectrics in helium-cooled high-temperature superconducting (HTS) cables. Polyimide, polyamide, and polymethyl methacrylate are utilized as host polymers. The composite samples are synthesized through an in situ process, dispersing silicon dioxide nanoparticles throughout the polymer hosts. Fourier transform infrared spectroscopy and scanning electron microscopy were employed to validate the synthesis of each composite configuration. Thin film samples of each configuration were also tested for their dielectric strength at both room (300 K) and cryogenic (92 K) temperatures. When going from room to cryogenic temperatures, all materials demonstrated a significant …

Pulse Width Modulation-Based Voltage Balancing And Circulating Current Control For Modular Multilevel Converters, Md Multan Biswas

Theses and Dissertations

In the last decade, because of some key features and advantages of Modular Multilevel Converter (MMC), it is widely applied for various Medium Voltage (MV) and High Voltage (HV) power electronic interfacing applications. The structure of MMCs varies by application but in general, they are composed of multiple Sub-Modules (SMs) which each contains a floating capacitor. For the operation of MMCs, capacitor voltages are required to remain equally set. This is referred to as the balanced condition and requires a method for SM Capacitor Voltage Balancing (CVB). Connections of SMs for most of the common MMC configurations result in additional …

Decellularization Strategies Of Naturally Derived Biomaterials For Tissue Engineering Applications, Julia Elizabeth Hohn

Theses and Dissertations

In 2017, over 3.5 million peripheral vascular surgeries were performed worldwide with over 400,000 vascular repair or replacement surgeries being performed in the United States each year alone. As the number of vascular repair surgeries, including both coronary and peripheral bypass grafting procedures, continues to increase each year, these statistics indicate an urgent need for more effective and readily available replacement materials. Regenerative medicine and tissue engineering (TE) approaches, including the design, fabrication, and validation of suitable biomaterials in vitro that direct the repair and regeneration of damaged tissues, have been proposed to alleviate this problem. While advanced biomaterials have …

Applications Of Laser Liftoff Technique For Wide Bandgap Power And Flexible Electronics, Md Didarul Alam

Theses and Dissertations

Wide bandgap (WBG) AlGaN/GaN and ultrawide bandgap (UWBG) AlGaN/AlGaN III-nitride high electron mobility transistors (HEMTs) have come a long way since their initial demonstration and are desired for a multitude of applications in deep-scaled high-frequency, high-voltage, high-current, and high-temperature power electronics. Although AlGaN/GaN HEMTs have recently become state-of-the-art in consumer electronics chargers and amplifiers, the performance of the devices is limited by severe self-heating which significantly reduce their efficacy in demanding applications that require high-current density. One strategy to reduce this self-heating effect in GaN HEMTs is to use high thermal conductivity SiC or bulk AlN substrates. While this approach …

Closed Form Implicitly Integrated Models For Computationally Efficient Simulation Of Power Electronics, Andrew Wunderlich

Theses and Dissertations

This work describes novel closed-form, implicitly integrated (CF-implicit) models of switched-mode power converters which feature implicit integration but require no iterative numerical solving algorithm for evaluation because they are explicitly solved prior to model execution. The derived models capture the large-signal dynamic behavior of the power converters, so their use and accuracy are not limited to any one set of operating conditions. These models can be implemented in any computational environment, including directly on an existing embedded controller as a digital twin. Since no iterative solver is required, the models are highly computationally efficient and have a very predictable worst-case …

Mimo Antenna Systems For Wireless Handheld Devices, Ahmed H. Abdelgawwad

Theses and Dissertations

Mobile communications have seen tremendous growths in the last decades in the form of smartphones, watches, wireless enabled Personal Digital Assistants (PDAs) and so on. The current and future wireless communication systems require high data-rate capabilities to support high speed needs of users in modern applications. Multiple-input multiple-output (MIMO) antenna systems have become the most promising candidate to support the increased data demand. Therefore, they have emerged as an integral part of the new 5G wireless standard. One key challenge regarding MIMO systems for the handheld is to be able to successfully accommodate multiple miniature platform integrated antennas within a …

Low Temperature Dielectric Strength Of Polyimide-Silica Nanocomposites For Applications In High-Temperature Superconducting Cables, Michael John Mccaffrey

Theses and Dissertations

Gaseous helium is often considered as an alternative to liquid nitrogen to cool modern high-temperature superconducting cables in support of increased power capacity and/or reduction of required cable size. However, the small size of helium molecules and relatively poor dielectric strength of helium gas create challenges which limit the usefulness of modern cable dielectrics. Continuous dielectric coatings have been considered as an alternative to traditional lapped tape dielectrics to support gaseous helium refrigerants, but unmatched thermal contraction between the coating and cable components would induce failures due to mechanical stress. Composite materials have been considered as a means of matching …

A Machine Learning Framework For Automatic Speech Recognition In Air Traffic Control Using Word Level Binary Classification And Transcription, Fowad Shahid Sohail

Theses and Dissertations

Advances in Artificial Intelligence and Machine learning have enabled a variety of new technologies. One such technology is Automatic Speech Recognition (ASR), where a machine is given audio and transcribes the words that were spoken. ASR can be applied in a variety of domains to improve general usability and safety. One such domain is Air Traffic Control (ATC). ASR in ATC promises to improve safety in a mission critical environment. ASR models have historically required a large amount of clean training data. ATC environments are noisy and acquiring labeled data is a difficult, expertise dependent task. This thesis attempts to …

A Broad Spectrum Defense Against Adversarial Examples, Sean Mcguire

Theses and Dissertations

Machine learning models are increasingly employed in making critical decisions across a wide array of applications. As our dependence on these models increases, it is vital to recognize their vulnerability to malicious attacks from determined adversaries. In response to these adversarial attacks, new defensive mechanisms have been developed to ensure the security of machine learning models and the accuracy of the decisions they make. However, many of these mechanisms are reactionary, designed to defend specific models against a known specific attack or family of attacks. This reactionary approach does not generalize to future "yet to be developed" attacks. In this …

High Power Microwave Operational Exposure Detection Using Thermoacoustic Wave Generation In Lossy Dielectric Polymers, James J. Frey

Theses and Dissertations

A feasibility analysis for the use of microwave-induced thermoacoustic (TA) wave generation in lossy dielectric media to detect pulsed high power microwave directed energy weapons in force health protection applications was conducted based on a series of empirical and computational investigations. A potential target volume material, carbon-loaded polytetrafluoroethylene, was identified for further study based on anticipated complex dielectric properties, with laboratory measurements of select electromagnetic (EM), thermal, and elastic material properties of relevance to the TA effect conducted to determine parameter values. A planar geometry TA-based signal chain model using thin film piezoelectric sensors was developed for both finite element …

Multichannel Blind Deconvolution Of Circularly Polarized Imagery, Patrick B. Cunningham

Theses and Dissertations

Current methods can be used to recreate an expected Stokes polarization vector from measured light for characterization purposes. However, this only applies to three of the Stokes parameters, that is, the linear polarization components. Circular polarization is not currently being utilized for object characterization because the mathematical complexity is greater than for that of linear polarization. This research will analyze a way to expand existing algorithms to include circular polarization and enable the complete reconstruction of the Stokes vector from the measured light into a blind deconvolution algorithm for Stokes estimation and image reconstruction.

Development Of A Security-Focused Multi-Channel Communication Protocol And Associated Quality Of Secure Service (Qoss) Metrics, Paul M. Simon

Theses and Dissertations

The threat of eavesdropping, and the challenge of recognizing and correcting for corrupted or suppressed information in communication systems is a consistent challenge. Effectively managing protection mechanisms requires an ability to accurately gauge the likelihood or severity of a threat, and adapt the security features available in a system to mitigate the threat. This research focuses on the design and development of a security-focused communication protocol at the session-layer based on a re-prioritized communication architecture model and associated metrics. From a probabilistic model that considers data leakage and data corruption as surrogates for breaches of confidentiality and integrity, a set …

A Deep Learning Approach For Airport Runway Identification From Satellite Imagery, Mahmut Gemici

Theses and Dissertations

The United States lacks a comprehensive national database of private Prior Permission Required (PPR) airports. The primary reason such a database does not exist is that there are no federal regulatory obligations for these facilities to have their information re-evaluated or updated by the Federal Aviation Administration (FAA) or the local state Department of Transportation (DOT) once the data has been entered into the system. The often outdated and incorrect information about landing sites presents a serious risk factor in aviation safety. In this thesis, we present a machine learning approach for detecting airport landing sites from Google Earth satellite …

Short-Term Electricity Price Point And Probabilistic Forecasts, Chenxu Zhang

Theses and Dissertations

Accurate short-term electricity price forecasts are essential to all electricity market participants. Generation companies adopt price forecasts to hedge generation shortage risks; load serving entities use price forecasts to purchase energy with low cost; and trading companies utilize price forecasts to arbitrage between markets.

Currently, researches on point forecast mainly focus on exploring periodic patterns of electricity price in time domain. However, frequency domain enables us to identify more information within price data to facilitate forecast. Besides, price spike forecast has not been fully studied in the existing works. Therefore, we propose a short-term electricity price forecast framework that analyzes …

Modeling Supercritical Fluids And Fabricating Electret Films To Address Dielectric Challenges In High-Power-Density Systems, Farhina Haque

Theses and Dissertations

Wide bandgap (WBG) devices and power electronic converters (PEC) that enable the dynamic control of energy and high-power density designs inevitably contain defects including sharp edges, triple points, and cavities, which result in local electric field enhancements. The intensified local electric stresses cause either immediate dielectric breakdown or partial discharge (PD) that erodes electrical insulators and accelerates device aging. With the goal of addressing these dielectric challenges emerging in power-dense applications, this dissertation focuses on 1) modeling the dielectric characteristics of supercritical fluids (SCFs), which is a new dielectric medium with high dielectric strength and high cooling capability; and 2) …

Nonreciprocal Surface Waves On Gyrotropic Interfaces, Alexander Martin Holmes

Theses and Dissertations

In this dissertation, the properties of highly nonreciprocal (unidirectional) surface waves guided along the interface between free-space and various 2D and 3D gyrotropic continua are investigated using analytic, numerical, and experimental methods. From a classical electromagnetics perspective, nonreciprocity in the dispersion of surface wave modes supported by the interface is achieved by breaking both time-reversal and space-inversion symmetries in the collective response of the waveguide, which consists of the two interfaced materials. More recently, however, a connection to momentum space topology via the bulk-edge correspondence principle has been made for gyrotropic continua, providing additional insights into the underlying physics that …

Applications Of Machine Learning In Medical Prognosis Using Electronic Medical Records, Farnaz Hajiahmadifoomani

Theses and Dissertations

Approximately 84 % of hospitals are adopting electronic medical records (EMR) In the United States. EMR is a vital resource to help clinicians diagnose the onset or predict the future condition of a specific disease. With machine learning advances, many research projects attempt to extract medically relevant and actionable data from massive EMR databases using machine learning algorithms. However, collecting patients' prognosis factors from Electronic EMR is challenging due to privacy, sensitivity, and confidentiality. In this study, we developed medical generative adversarial networks (GANs) to generate synthetic EMR prognosis factors using minimal information collected during routine care in specialized healthcare …

Nonreciprocal Electromagnetics Of Layered Media, Samaneh Pakniyat

Theses and Dissertations

In plasmonic systems, interaction of light and surface plasmons leads to excitation of surface plasmon polaritons (SPPs) carrying energy on the surface. In an isotropic plasmonic system, the SPPs optical response is reciprocal, which means that the forward and backward surface waves have identical propagation behaviors and SPPs refract when they encounter a discontinuity on the surface. In order to excite SPPs resilient to the surface disorders, the system reciprocity needs to be broken by different techniques such as applying an external magnetic bias. In this case, the plasmonic system becomes a gyrotropic medium. Recently, it has been shown that …

Tracking Control Of Quadrotors, Shihab Ahmed

Theses and Dissertations

In this thesis, the tracking control problem of a 6 DOF quadrotor is considered, and different control method is proposed considering optimal control, parametric and nonparametric uncertainty, input saturation, and distributed formation control. An optimal control approach is developed for single quadrotor tracking by minimizing the cost function. For uncertainties of the dynamic system, a robust adaptive tracking controller is proposed with the special structure of the dynamics of the system. Considering the uncertainty and input constraints, a robust adaptive saturation controller is proposed with the aid of an auxiliary compensated system. Decentralized formation control method for quadrotors is presented …

Detection Of Rotorcraft Landing Sites: An Ai-Based Approach, Abdullah Nasir

Theses and Dissertations

The updated information about the location and type of rotorcraft landing sites is an essential asset for the Federal Aviation Administration (FAA) and the Department of Transportation (DOT). However, acquiring, verifying, and regularly updating information about landing sites is not straightforward. The lack of current and correct information about landing sites is a risk factor in several rotorcraft accidents and incidents. The current FAA database of rotorcraft landing sites contains inaccurate and missing entries due to the manual updating process. There is a need for an accurate and automated validation tool to identify landing sites from satellite imagery. This thesis …