Engineering Commons^™

Improved Multi-Task Learning Based On Local Rademacher Analysis, Niloofar Yousefi

Electronic Theses and Dissertations

Considering a single prediction task at a time is the most commonly paradigm in machine learning practice. This methodology, however, ignores the potentially relevant information that might be available in other related tasks in the same domain. This becomes even more critical where facing the lack of a sufficient amount of data in a prediction task of an individual subject may lead to deteriorated generalization performance. In such cases, learning multiple related tasks together might offer a better performance by allowing tasks to leverage information from each other. Multi-Task Learning (MTL) is a machine learning framework, which learns multiple related …

Wrong-Way Driving: A Regional Approach To A Regional Problem, Md. Omar Faruk

Electronic Theses and Dissertations

Wrong-way driving (WWD) has been problematic on United States highways for decades despite its rare occurrence. Since WWD crashes are rare, recent researchers have studied WWD non-crash events such as WWD 911 calls and WWD citations to understand the overall nature and trend of WWD. This paper demonstrates the regional nature of the WWD problem and proposes regional transportation systems management and operations (Regional TSM&O) solutions to combat this problem. Specifically, it was found that 11% of all WWD multi-data events (e.g., multiple 911 calls for the same WWD event) traveled from one county to another. Additionally, 30% of all …

Polyelectrolyte And Hydrogel Stabilized Liquid Crystal Droplets For The Detection Of Bile Acids, Jinan Deng

Electronic Theses and Dissertations

Liquid crystal (LC) droplets show great potential as an optical probe for sensor applications due to their large surface areas and stimuli-response director configurations. Bile acids with amphipathic properties, which are formed in liver and secreted into the small intestine, play an important role in the digestion of fats and fat-soluble vitamins. After the digestion process, most of bile acids are recycled back to the liver and ready for the next digestion. Only a few of them are excreted into body fluids. However, there is significant increases in the concentration level of bile acids in body fluids for patients with …

Ellipsometric Measurements Of Alternative Fuels, Leigh Nash

Electronic Theses and Dissertations

Alternative jet fuels will be important in the future to ensure cleaner burning, reliable, and reasonably priced air transportation. One important property that must meet certification standards is the fuel's thermal stability, or its ability to withstand heating before breaking down. Jet fuels are used as engine coolants, and thermally unstable fuels can form deposits in the fuel delivery systems, leading to a loss of fuel flow. In the past, the thermal stability of a fuel was rated using a color standard method. The color of the deposit left on a metal tube that had been heated and exposed to …

Voltage Regulation Of Low Voltage Distribution Networks, Manisha Maharjan

Electronic Theses and Dissertations

The modern voltage distribution systems consist of distributed generation (DG), like photovoltaics (PV) and wind. These resources are inexhaustible and environmentally friendly. The existing low voltage (LV) distribution networks are typically designed for unidirectional power flow. The integration of DG makes the LV distribution networks prone to difficulties related to voltage, frequency, and power quality. The main challenges in the integration of DG occur due to the intermittent nature of DG. The amount of DG compared with the total generation resource on a power system network is measured as penetration. The system undergoes through reverse power flow when there is …

A Dynamic Scaling Methodology For Improving Performance Of Big Data Systems, Nashmiah Alhamdawi

Electronic Theses and Dissertations

The continuous growth of data volume in various fields such as, healthcare, sciences, economics, and business has caused an overwhelming flow of data in the last decade. The overwhelming flow of data has raised challenges in processing, analyzing, and storing data, which lead many systems to face an issue in performance. Poor performance of systems creates negative impact such as delays, unprocessed data, and increasing response time. Processing huge amounts of data demands a powerful computational infrastructure to ensure that data processing and analysis success [7]. However, the architectures of these systems are not suitable to process that quantity of …

Thermal And Waveguide Optimization Of Broad Area Quantum Cascade Laser Performance, Matthew Suttinger

Electronic Theses and Dissertations

Quantum Cascade Lasers are a novel source of coherent infrared light, unique in their tunability over the mid-infrared and terahertz range of frequencies. Advances in bandgap engineering and semiconductor processing techniques in recent years have led to the development of highly efficient quantum cascade lasers capable of room temperature operation. Recent work has demonstrated power scaling with broad area quantum cascade lasers by increasing active region width beyond the standard ~10 ?m. Taking into account thermal effects caused by driving a device with electrical power, an experimentally fitted model is developed to predict the optical power output in both pulsed …

System For Metal Coated Fiber Fabrication, Da Zhang

Electronic Theses and Dissertations

For many specific applications, such as sensors, aerospace, chemical industry, deep-well oil-field industry, metal-coated fiber shows strong abilities to satisfy people's requirement. With in-line coating technology, we are able to coat Aluminum on the fibers. Using electromagnetic induction, we can easily heat an electrically conducting thing such as a metal with the eddy current. This process is defined as Induction heating. And we will melt the Aluminum by this induction heating during drawing the fibers on the tower. Introduce the fiber tower system. The drawing process of in-line technology is formed of the following steps: Position, Melting, Forming into fibers, …

Picosecond Yb-Doped Fiber Amplifier, Weibin Zhu

Electronic Theses and Dissertations

Due to its versatility, rare earth doped fiber amplifier (RDFA) has attracted a lot of researchers worldwide in recent years. Depends on different kinds of rare earth ion, RDFA can be categorized into neodymium doped fiber amplifier (NDFA), erbium doped fiber amplifier (EDFA), thulium doped fiber amplifier (TDFA), and so forth. Among many kinds of RDFA, the ytterbium doped fiber amplifier (YDFA) has received even more interest, especially in high power application, mainly because of its broad gain bandwidth and high conversion efficiency which are due to its relatively simple electronic structure. The purpose of this research is to study …

Photothermal Lensing In Mid-Infrared Materials, Justin Cook

Electronic Theses and Dissertations

A thorough understanding of laser-materials interactions is crucial when designing and building optical systems. An ideal test method would probe both the thermal and optical properties simultaneously for materials under large optical loads where detrimental thermal effects emerge. An interesting class of materials are those used for infrared wavelengths due to their wide spectral transmission windows and large optical nonlinearities. Since coherent sources spanning the mid-wave and long-wave infrared wavelength regions have only become widely available in the past decade, data regarding their thermal and optical responses is lacking in literature. Photothermal Lensing (PTL) technique is an attractive method for …

Filament Wavefront Evolution, Daniel Thul

Electronic Theses and Dissertations

Filamentation is a complex process that gives rise to many nonlinear interactions. However, the fundamentals of filament formation and propagation can be explained in terms of two dominant mechanisms: Kerr self-focusing and plasma defocusing. The first to occur, self-focusing, is responsible for an increase in irradiance through beam collapse. This process requires sufficient initial peak power, on the order of gigawatts for near infrared beams in air. Plasma defocusing then arrests the collapse process once the irradiance reaches the ionization threshold of the medium. These two processes balance each other in an extended plasma channel known as a filament. A …

Novel Photonic Resonance Arrangements Using Non-Hermitian Exceptional Points, Hossein Hodaei

Electronic Theses and Dissertations

In recent years, non-Hermitian degeneracies also known as exceptional points (EPs) have emerged as a new paradigm for engineering the response of optical systems. EPs can appear in a wide class of open non-Hermitian configurations. Among different types of non-conservative photonic systems, parity-time (PT) symmetric arrangements are of particular interest since they provide an excellent platform to explore the physics of exceptional points. In this work, the intriguing properties of exceptional points are utilized to address two of the long standing challenges in the field of integrated photonics- enforcing single mode lasing in intrinsically multimode cavities and enhancing the sensitivity …

Generation Of High-Flux Attosecond Pulses And Towards Attosecond-Attosecond Pump-Probe Experiments, Yang Wang

Electronic Theses and Dissertations

At present, the energy of a single isolated attosecond pulse is limited to nanojoule levels. As a result, an intense femtosecond pulse has always been used in combination with a weak attosecond pulse in time-resolved experiments. To reach the goal of conducting true attosecond pump-attosecond probe experiments, a high flux laser source has been developed that can potentially deliver microjoule level isolated attosecond pulses in the 50 eV range, and a unique experimental end station has been fabricated and implemented that can provide precision control of the attosecond-attosecond pump-probe pulses. In order to scale up the attosecond flux, a unique …

Segmental Movement Compensations In Patients With Transtibial Amputation Identified Using Angular Momentum Separation, Brecca M. M. Gaffney

Electronic Theses and Dissertations

Patients with unilateral dysvascular transtibial amputation (TTA) adopt movement compensations that are required to maintain balance and achieve ambulation in the absence of ankle plantar flexion, and result in increased and asymmetric joint loading patterns. As a result, this population is at an increased risk of overuse injuries, such as low back pain (LBP). Clinical gait analysis is used to guide diagnostics in movement retraining following amputation, and is performed using instrumented (research based) or observational analyses (clinically based). However, instrumented analyses are currently impractical in most clinical settings due to expense and computational limitations. This dissertation presents the use …

Geotechnical Properties Of The Travis Peak (Hosston) Formation In East Texas: A Compressive And Tensile Strength Analysis Using Regression Analysis., Pawan Kakarla

Electronic Theses and Dissertations

The estimation of rock mass strength is a key parameter in geotechnical engineering which is used in the design of geotechnical structures like tunnels, dams and slopes. Geotechnical engineering is the branch of civil engineering which works on the principles of soil and rock mechanics to evaluate subsurface conditions, stability of slopes, foundations of structures and construction of earthworks. The main focus of this study was to calculate the strength of Lower Cretaceous Travis Peak Formation rocks of East Texas and to check the accuracy by comparing it with Regression analysis. The parameters which were used were the Uniaxial Compression …

Characterization And Delineation Of Karst Geohazards Along Rm652 Using Electrical Resistivity Tomography, Culberson County, Texas, Adam F. Majzoub

Electronic Theses and Dissertations

The Delaware Basin of West Texas and southeastern New Mexico is the major western subdivision of the Permian Basin and a northern extension of the Chihuahuan Desert. The major evaporite unit within the Delaware Basin is the Castile Formation, which consists of gypsum/anhydrite and is highly susceptible to dissolution and karsting. Manifestations of karst within the Castile outcrop are abundant and include sinkholes, subsidence features and caves, both epigene and hypogene in origin.

Land reconnaissance surveys conducted during the summer of 2015 documented abundant karst landforms in close proximity to a major thoroughfare, RM 652, in Culberson County, Texas. 2D …

Single Carrier Frequency Domain Equalization And Energy Efficiency Optimization For Mimo Cognitive Radio., Xiaohui Zhang

Electronic Theses and Dissertations

This dissertation studies two separate topics in wireless communication systems. One topic focuses on the Single Carrier Frequency Domain Equalization (SC-FDE), which is a promising technique to mitigate the multipath effect in the broadband wireless communication. Another topic targets on the energy efficiency optimization in a multiple input multiple output (MIMO) cognitive radio network. For SC-FDE, the conventional linear receivers suffer from the noise amplification in deep fading channel. To overcome this, a fractional spaced frequency domain (FSFD) receiver based on frequency domain oversampling (FDO) is proposed for SC-FDE to improve the performance of the linear receiver under deep fading …

Practical Knowledge In Electrical Engineering : Applying Lessons From Industry To The Classroom., Tayce Lassiter

Electronic Theses and Dissertations

Objective: To identify and develop solutions for known gaps in existing electrical engineering curricula, by creating instruction modules applicable in a variety of settings. These instructional packages include: conductor sizing, conduit routing, how to read and create a P&ID, arc flash calculations, and area classification. With regards to conductor sizing, the importance of specifying the correct size of conductor, the standard sizes of conductors, the types of conductor insulation, and finally detail the calculations of conductor sizing and voltage drop will be discussed. The conduit routing module will introduce the student to basic guidelines of conduit routing as well as …

Psychophysiological Analysis Of A Pedagogical Agent And Robotic Peer For Individuals With Autism Spectrum Disorders., Mohammad Nasser Saadatzi

Electronic Theses and Dissertations

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by ongoing problems in social interaction and communication, and engagement in repetitive behaviors. According to Centers for Disease Control and Prevention, an estimated 1 in 68 children in the United States has ASD. Mounting evidence shows that many of these individuals display an interest in social interaction with computers and robots and, in general, feel comfortable spending time in such environments. It is known that the subtlety and unpredictability of people’s social behavior are intimidating and confusing for many individuals with ASD. Computerized learning environments and robots, however, prepare a predictable, …

A Cad System For Early Diagnosis Of Autism Using Different Imaging Modalities., Marwa Maher Tawfik Ismail

Electronic Theses and Dissertations

The term “autism spectrum disorder” (ASD) refers to a collection of neuro-developmental disorders that affect linguistic, behavioral, and social skills. Autism has many symptoms, most prominently, social impairment and repetitive behaviors. It is crucial to diagnose autism at an early stage for better assessment and investigation of this complex syndrome. There have been a lot of efforts to diagnose ASD using different techniques, such as imaging modalities, genetic techniques, and behavior reports. Imaging modalities have been extensively exploited for ASD diagnosis, and one of the most successful ones is Magnetic resonance imaging(MRI),where it has shown promise for the early diagnosis …

Conductive Inks And Films Via Intense Pulsed Light., Gabriel L. Draper

Electronic Theses and Dissertations

This research focuses on the investigation of Earth abundant copper and carbon based nanomaterials that are subjected to Intense Pulsed Light Processing to create conductive films, as future flexible electronics and renewable energy solutions would benefit from the quick and scalable production of conductive films. Use of nanomaterials in their oxide/hydroxide forms leads to higher stability in aqueous inks for efficient large area solution deposition. IPL Processing utilized 2044 μs pulses ranging from 589 J - 2070 J over an area of 1.9 cm x 30.5 cm, with energy densities of 10.1, 12.8, 15.8, 19.2, 22.9, 26.8, 31.1 and 35.7 …

Scalable Production And Applications Of Metal Oxide Nanowires., Tu Quang Nguyen

Electronic Theses and Dissertations

Metal oxide nanowires are materials of interest in number of applications such as lithium ion batteries, solar cells, catalyst support, and gas sensing due to their unique charge transport properties and short diffusion length scales. To incorporate nanowires for any applications, one would need hundreds of grams to kilograms of these nanowires. However, state-of-the-art methods for producing metal oxide nanowires are limited to producing only milligrams to a gram in a batch. Hence, there is a need to develop scalable and cost effective processes and reactors to address this challenge. Direct gas phase oxidation of zinc metal powders using a …

Computational Methods For The Analysis Of Functional 4d-Ct Chest Images., Ahmed Soliman Naeem Soliman

Electronic Theses and Dissertations

Medical imaging is an important emerging technology that has been intensively used in the last few decades for disease diagnosis and monitoring as well as for the assessment of treatment effectiveness. Medical images provide a very large amount of valuable information that is too huge to be exploited by radiologists and physicians. Therefore, the design of computer-aided diagnostic (CAD) system, which can be used as an assistive tool for the medical community, is of a great importance. This dissertation deals with the development of a complete CAD system for lung cancer patients, which remains the leading cause of cancer-related death …

Mechanism Of Interaction Of Peptide Modified Nanoparticles With Porphyromonas Gingivalis., Ankita Jain

Electronic Theses and Dissertations

Studies suggest that P. gingivalis functions as a keystone pathogen and interacts with primary colonizers in the supragingival biofilm such as S. gordonii. This interaction contributes to the initial colonization of the oral cavity by P. gingivalis and thus represents a potential target for therapeutic intervention. We have identified a peptide (BAR) derived from the streptococcal SspB protein that functions to inhibit P. gingivalis adherence to S. gordonii. In addition, we showed that nanoparticles (NPs) functionalized with BAR inhibit this interaction more potently than free soluble peptide, possibly by promoting interaction with P. gingivalis at higher valency than …

Dynamic Warehouse Optimization Using Predictive Analytics., Parvaneh Jahani

Electronic Theses and Dissertations

The forward area is a small area of a warehouse with a low picking cost. Two approaches that are investigated for selecting the SKUs of this area and the allocated space are the static and the dynamic approaches. In the case that decisions about the forward area are made periodically (e.g. yearly) and the products' demand patterns are completely ignored, the FRP is static. We developed two heuristics that solve the large discrete assignment, allocation, and sizing problem simultaneously. Replenishing the same product in the same place of the forward area brings about a ``Locked" layout of the fast picking …

Reflectivity Of Light Emitting Diodes (Led) And Incandescent Lights On Concrete And Asphalt Pavements., Jeremy Elliott Rice

Electronic Theses and Dissertations

The purpose of this study is to investigate the reflectivity of light on concrete and asphalt pavement systems. In 1983, the Illuminating Engineering Society (IES) published the first recommended practice (RP-8) for the design of roadway and parking lot lighting. This design method implemented empirically tested factors which were defined as the “reduced luminance coefficients” or the R-Tables. The R-Tables are essential for proper design of light pole installation dimensions, required power, and the distribution of light. The originally tested pavements are not necessarily representative of modern pavement materials used today. Moreover, recent Light Emitting Diodes (LED) are a relatively …

Strategies And Techniques For Fabricating Mems Bistable Thermal Actuators., Dilan Ratnayake

Electronic Theses and Dissertations

Bistable elements are beginning to appear in the field of MEMS as they allow engineers to design sensors and actuators which require no electrical power and possess mechanical memory. This research focuses on the development of novel strategies and techniques for fabricating MEMS bistable structures to serve as no electrical power thermal actuators. Two parallel strategies were explored for the design and fabrication of the critical bistable element. Both strategies involved an extensive material study on candidate thin film materials to determine their temperature coefficient of expansion and as-deposited internal stress properties. Materials investigated included titanium tungsten, Invar, silicon nitride …

An Integrated Economic Equilibrium Model For Electricity Markets., Swapna Pothabathula

Electronic Theses and Dissertations

The increasing energy challenges worldwide are forcing researchers to explore ways for energy systems that work more efficiently on their own and with each other. This thesis develops an integrated electricity market equilibrium model (EMEM) as a mixed complementarity problem (MCP). In particular, we first develop an equilibrium model to study an electricity market consisting of coal producers, electricity generation firms, natural gas producers, natural gas marketers, natural gas pipeline owners, natural gas consumers and electricity consumers. The equilibrium model not only captures a decentralized optimization for each player but considers the interaction amongst players. Second, we formulate the equilibrium …

Experimental Observation Of The Relationship Between The Pressure Drop And Flow Rate Of Radial Flow Through Porous Media., Matthew William Okruch

Electronic Theses and Dissertations

This research experimentally observed the relationship between pressure drop and flow rate for high velocity, radial flow through porous media. The criterion for what represents high velocity is a function of the Reynold’s number of the flow. Pressure drop – flow rate curves were developed by flowing air and water through the porous carbon block samples. Each sample’s permeability was calculated from on the air test results. Each sample’s porosity was determined through digital microscope image analysis. Darcy’s Law, the Forchheimer equation, and the Ergun equation were converted to the radial flow domain and compared to the experimental data. The …

Order Picking Strategies For Healthcare Warehouses., Ehsan Khodabandeh

Electronic Theses and Dissertations

Order picking is the process of collecting goods and items in specified quantities from storage locations, in response to customer orders. Since many labor resources are involved in this process, finding ways to make it more efficient have been a primary goal for researchers and practitioners. Determining a better allocation of products to the storage areas, finding the best route and sequence to pick multiple products, and choosing the best picking policies to minimize congestion in the aisles are just a few of many objectives regarding order picking process. Due to regulatory compliances and the chance of product spoilage, additional …