Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network™

Open Access. Powered by Scholars. Published by Universities.®

2020

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 166471 - 166500 of 169281

Full-Text Articles in Entire DC Network

Pervasive Spectrum Sharing For Improved Wireless Experience, Mostafizur Rahman Jan 2020

Pervasive Spectrum Sharing For Improved Wireless Experience, Mostafizur Rahman

Electronic Theses and Dissertations, 2020-2023

Spectrum sharing among cellular users has been a promising approach to attain better efficiency in the use of the limited spectral bands. The existing dynamic spectrum access techniques include sharing of the licensed spectrum bands by allowing other 'secondary' users to use the bands if the licensee 'primary' user is idle. This primary-secondary spectrum sharing is limited in terms of design space, and may not be sufficient to meet the ever-increasing demand of connectivity and high signal quality to improve the end-users' wireless experience. The next step to increase spectrum efficiency is to design markets where sharing takes place pervasively …

Go to article

An Investigation Of Postsecondary Education Program: Students With Intellectual Disabilities, Anna Schoenfeld Jan 2020

An Investigation Of Postsecondary Education Program: Students With Intellectual Disabilities, Anna Schoenfeld

Electronic Theses and Dissertations, 2020-2023

Since 2008, the number of students with intellectual disabilities and the number of postsecondary education programs supporting students with intellectual disabilities have drastically increased on college campuses in the United States. The purpose of this document analysis qualitative research was to explore the publicly available information provided by universities with Postsecondary Education Programs (PSP) that have Southern Association of College and Schools (SACS) accreditation and receive Transition Program for Students with Intellectual Disabilities (TPSID) grant funding. K. Patricia Cross's Chain-of-Response (COR) model was the conceptual framework used to frame this andrological inquiry. Lack of information, as identified by Cross (1981) …

Go to article

A Mixed Method Analysis Of Factors Influencing Success And Failure In Undergraduate Engineering Capstone Design Experiences, Kurt Stresau Jan 2020

A Mixed Method Analysis Of Factors Influencing Success And Failure In Undergraduate Engineering Capstone Design Experiences, Kurt Stresau

Electronic Theses and Dissertations, 2020-2023

The engineering undergraduate curriculum presents substantial opportunities for improvement. Society is calling for a transformation. As the culminating experience for undergraduate engineering students, capstone design team projects represent a window on the curriculum and a particularly fertile ground for understanding these opportunities. However, the factors that influence success and failure in capstone remains an area of inquiry. The work presented here proposes to help us develop a deeper understanding of these factors. The research presented here uses a mixed methods analysis approach for identifying the critical factors impacting capstone design team success, where success is defined from both student and …

Go to article

Seismic Design Optimization Of Steel Structures Using Genetic Algorithm, Tiancheng Wang Jan 2020

Seismic Design Optimization Of Steel Structures Using Genetic Algorithm, Tiancheng Wang

Electronic Theses and Dissertations, 2020-2023

Current seismic codes do not incorporate a well-established methodology for the selection of passive dampers type and their topological distribution and properties along the height of structures. Achieving the intended performance is made more complicated when structures are subject to extreme events and operate well within their inelastic range. This thesis utilizes a self-organizing genetic algorithm (soGA) with probabilistic gene-by-gene crossover and an adaptive active ground motion subset scheme to efficiently find optimal designs of low-rise steel frames subject to large number of extreme ground motions. Different types of passive dampers were considered, while the steel frames were modeled using …

Go to article

Mean Field Optimal Control And Related Problems, Wei Yan Jan 2020

Mean Field Optimal Control And Related Problems, Wei Yan

Electronic Theses and Dissertations, 2020-2023

It has been decades since the first paper that mean field problems were studied. More and more problems are considered or solved as new methods and new concepts have been developed. In this dissertation, we will present a series of results on (recursive) mean field stochastic optimal control problems. Comparing our results with those in the classical stochastic optimal control theory, there are following significant differences. First, the value function of a mean field optimal control problem is not Markovian any more, even when coefficient functions in the problem are deterministic. Second, the cost functional we considered is induced by …

Go to article

First-Year Doctoral Students' Academic Writing Development: The Native- And Nonnative-Speaking Perspectives, Ying Xiong Jan 2020

First-Year Doctoral Students' Academic Writing Development: The Native- And Nonnative-Speaking Perspectives, Ying Xiong

Electronic Theses and Dissertations, 2020-2023

Academic writing is central to doctoral growth. The purpose of this study was to better understand the similarities and differences between first-year native- and nonnative-speaking doctoral students in terms of academic writing and writer development. Data were collected for two semesters, including observational notes, transcribed audio diaries and interviews, and writing samples from three first-year doctoral students from an applied field of social science. Ethnographic data analysis described how text production and composing processes changed over the first year in relation to social and cultural factors. The first year of the doctoral program was critical to their growth as writers …

Go to article

The Effect Of Economic Conditions On The Prevalence Of Abusive Supervisory Behaviors: A Cross-Temporal Meta-Analysis, Xinyue Zhao Jan 2020

The Effect Of Economic Conditions On The Prevalence Of Abusive Supervisory Behaviors: A Cross-Temporal Meta-Analysis, Xinyue Zhao

Electronic Theses and Dissertations, 2020-2023

The antecedents of abusive supervisory behaviors have been largely examined at the individual and organizational level. Hardly any attempts have been made to investigate abusive supervisory behaviors in a context broader than the organization. I try to answer the question "does a recession really unleash abusive supervisory behaviors?" by conducting a cross-temporal meta-analysis to examine the effect of economic conditions on the prevalence of abusive supervisory behaviors. Considering economic conditions as an antecedent to abusive supervisory behaviors provides a more comprehensive understanding of the phenomena. I proposed four reasons to explain how economic conditions affect employee's perception of abusive supervisory …

Go to article

Tunable Few- To Many-Cycle Source For High-Order Harmonic Generation And Time-Resolved Spectroscopy, John Beetar Jan 2020

Tunable Few- To Many-Cycle Source For High-Order Harmonic Generation And Time-Resolved Spectroscopy, John Beetar

Electronic Theses and Dissertations, 2020-2023

The temporal confinement of laser light pulses to durations approaching the optical period, and the subsequent conversion of these pulses into extreme ultraviolet and x-ray wavelengths through the process of high-order harmonic generation (HHG), has enabled measurement and control of ultrafast processes spanning picosecond to attosecond timescales. Typically achieved by nonlinear compression of multi-cycle pulses in gas-filled hollow-core fibers, compression to single-and even sub-cycle durations is now becoming routine due to the availability of state-of-the-art Ti:sapphire laser amplifiers outputting millijoule level pulses with pulse durations below ten cycles. Even so, reliance on mJ-level Ti:sapphire lasers has in most cases limited …

Go to article

Investigating How First-Year College Students Use Smartphones To Receive Parental Support, Jacob Bonne Jan 2020

Investigating How First-Year College Students Use Smartphones To Receive Parental Support, Jacob Bonne

Electronic Theses and Dissertations, 2020-2023

The purpose of this study was to understand how first-year undergraduate college students use smartphones to receive parental support. A conceptual framework was implemented to frame the research and focused on first-year college student transitions and development within the context of parental support. A Phenomenological methodology with semi-structured interviews was implemented which explored the phenomenon from both immersive and holistic perspectives. Seven themes emerged from the analysis: decision-making, academic pathways, autonomy, emotional support, access, safety, and preparation. This study provided two recommendations for practice, including to educate students and parents about parental support and to educate parents about specific student …

Go to article

Death In The Land Of Flowers: Environment As Enemy In The Second Seminole War, Nicholas Brown Jan 2020

Death In The Land Of Flowers: Environment As Enemy In The Second Seminole War, Nicholas Brown

Electronic Theses and Dissertations, 2020-2023

This thesis argues that Florida's natural environment was one of the United States Army's most formidable enemies during the Second Seminole War (1835–42), and that environmental factors, more than hostilities from Native peoples themselves, led the United States to abandon the War. Many White soldiers from the North were unprepared to cope with the environmental challenges posed by Florida. In order to build a foundation for this argument, the thesis examines how previous newcomers to Florida dealt with the environment, from the original First Peoples who arrived several thousand years ago, to European explorer/colonizers, to White Americans in the decades …

Go to article

Operability And Wave Characterization Of Hydrogen And Oxygen Fed Rotating Detonation Rocket Engine, Robert Burke Jan 2020

Operability And Wave Characterization Of Hydrogen And Oxygen Fed Rotating Detonation Rocket Engine, Robert Burke

Electronic Theses and Dissertations, 2020-2023

Recently, novel experimental evidence of continuous rotating detonations for gaseous H2/O2 propellants with a rotating detonation rocket engine (RDRE) was attained on the 3-inch Air Force Research Laboratory (AFRL) Distribution A RDRE, with the fuel and oxidizer injectors modified for H2/O2 gas propellants. Evident in previous experiments, detonation instabilities arising from upstream deflagration, from recirculation zones, and from insufficient gas mixing challenged resolution of detonation wave behavior from back-end imaging with the available optical equipment. Images were often over-illuminated from both the high amount of deflagration in the plume and the higher density of detonation waves in the annulus coupled …

Go to article

3d Localization Of Defects In Facility Inspections, Nicholas Califano Jan 2020

3d Localization Of Defects In Facility Inspections, Nicholas Califano

Electronic Theses and Dissertations, 2020-2023

Wind tunnels are crucial facilities that support the aerospace industry. However, these facilities are large, complex, and pose unique maintenance and inspection requirements. Manual inspections to identify defects such as cracks, missing fasteners, leaks, and foreign objects are important but labor and schedule intensive. The goal of this thesis is to utilize small Unmanned Aircraft Systems with onboard cameras and computer vision-based analysis to automate the inspection of the interior and exterior of NASA's critical wind tunnel facilities. Missing fasteners are detected as the defect class, and existing fasteners are detected to provide potential future missing fastener sites for preventative …

Go to article

On Patching Learning Discrepancies In Neural Network Training, Mohamed Elfeki Jan 2020

On Patching Learning Discrepancies In Neural Network Training, Mohamed Elfeki

Electronic Theses and Dissertations, 2020-2023

Neural network's ability to model data patterns proved to be immensely useful in a plethora of practical applications. However, using the physical world's data can be problematic since it is often cluttered, crowded with scattered insignificant patterns, contain unusual compositions, and widely infiltrated with biases and imbalances. Consequently, training a neural network to find meaningful patterns in seas of chaotic data points becomes virtually as hard as finding a needle in a haystack. Specifically, attempting to simulate real-world multi-modal noisy distributions with high precision leads the network to learn an ill-informed inference distribution. In this work, we discuss four techniques …

Go to article

Investigation Of Recurrent Neural Network Architectures Based Deep Learning For Short-Term Traffic Speed Forecasting, Armando Fandango Jan 2020

Investigation Of Recurrent Neural Network Architectures Based Deep Learning For Short-Term Traffic Speed Forecasting, Armando Fandango

Electronic Theses and Dissertations, 2020-2023

The availability of large tranches of data and its influence on traffic flow, make the problem of short-term traffic speed prediction very complex in nature. For more than 40 years, various statistical time series forecasting methods have been applied for traffic speed prediction, and in the last 20 years, machine learning-based methods have gained prevalence. However, more recently, recurrent neural network (RNN) based methods have emerged to show better results for traffic speed prediction\cite{tian2015pred, zhao2017lstm,fu2017usin,chen2016long,dai2017deep,dai2019deep, kanestrom2017traf,shao2016traf,jia2017traf}. As the interest in applying RNN models to the traffic speed predictions started to grow, we found some critical and important unanswered questions with …

Go to article

Atomic Layer Deposition Of Oxide Materials For Passivated Carrier Selective Contact Solar Cells, Geoffrey Gregory Jan 2020

Atomic Layer Deposition Of Oxide Materials For Passivated Carrier Selective Contact Solar Cells, Geoffrey Gregory

Electronic Theses and Dissertations, 2020-2023

Silicon-based devices have dominated the industrial solar cell marketplace for several decades, thanks to the low bulk defect concentration and technological relevance of silicon substrates. This has led to an oversupply of dopant-diffused homojunction technologies, which suffer from significant performance losses at the metal-silicon contact interface. In response, the research community has developed carrier-selective heterojunction contacts, which separate the metal from the silicon absorber with heavily-doped silicon layers. These novel contacts provide the same asymmetrical conductivity as the diffused junction in the previous generations of silicon solar cells, but with less processing complexity and greater device performance. Still, the silicon …

Go to article

Parametric Investigation And Optimization For Inconel 718 Nickel-Based Superalloy In Laser Powder Bed Fusion, Thinh Huynh Jan 2020

Parametric Investigation And Optimization For Inconel 718 Nickel-Based Superalloy In Laser Powder Bed Fusion, Thinh Huynh

Electronic Theses and Dissertations, 2020-2023

Excellent weldability and high temperature stability make Inconel 718 (IN718) one of the most desired alloys to be produced by additive manufacturing (AM). Within the flourishing field of AM technology, laser powder bed fusion (LPBF) is a popular prospective candidate capable of fabricating complex and near net-shape engineering components that traditional manufacturing methods cannot accomplish. In this study, the effects of processing parameters on the relative density and microstructure was investigated. Gas atomized IN718 powders were used to fabricate cuboidal specimens via LPBF for metallographic characterization. The specimens were printed with independently varied laser power (125 - 350 W), laser …

Go to article

Designing Metal Nanocatalysts And Tuning Their Microenvironment For Gas-Involving Electrocatalysis, Lin Hu Jan 2020

Designing Metal Nanocatalysts And Tuning Their Microenvironment For Gas-Involving Electrocatalysis, Lin Hu

Electronic Theses and Dissertations, 2020-2023

In the development of renewable energy technologies, electrocatalysis plays a central role in energy conversion processes, such as fuel cells and electrochemical fuel synthesis. Development of such technologies relies on the rational design of electrocatalysts as well as understanding their interaction with the working environment. Here we focus on gas-involving electrocatalytic reactions, particularly nitrogen electroreduction to ammonia and formic acid electrooxidation to carbon dioxide. First, to understand the structure-activity relationships for nitrogen electroreduction on Ru, we prepared a series of size-controlled Ru nanoparticles using atomic layer deposition. Both catalytic activity and selectivity for ammonia production on Ru catalysts strongly depend …

Go to article

The Relationship Between Familism And Social Distancing Behaviors During The Covid-19 Pandemic, Thien-An Le Jan 2020

The Relationship Between Familism And Social Distancing Behaviors During The Covid-19 Pandemic, Thien-An Le

Electronic Theses and Dissertations, 2020-2023

Transmission of Coronavirus 2019 (COVID-19) occurs efficiently and from symptomatic and asymptomatic individuals, therefore making it highly infectious. As such, social distancing is generally recommended to mitigate the speed of transmission and decrease incidence, hospitalization, and mortality rates. Consistent with other chronic medical conditions, COVID-19 is disproportionately affecting Hispanic/Latinx and black populations. One inherent cultural concept, familism, might also serve to inhibit adherence to social distancing guidelines. Thus, the current study contributes to the growing literature on COVID-19, specifically examining barriers underscoring health disparities. This study evaluated Attitudinal Familism (AFS) and Behavioral Familism (BFS) as predictors of adherence of social …

Go to article

Adachigahara Project: A 3d Iterative Series, James Mitchell Jan 2020

Adachigahara Project: A 3d Iterative Series, James Mitchell

Electronic Theses and Dissertations, 2020-2023

This project tested an aesthetic use of 3D space to create alienation and immersion. It expanded upon it through iteration into other methods of cinematic alienation. To do this the project produced three short films each used the aesthetic of stereoscopic space. Two of the films were tested in conjunction with other methods of alienation while one served as a baseline. The project was able to render the spatial method of alienation and immersion, and found that other methods of alienation had an effect on it. While the project was able to test the use of 3D space to alienate …

Go to article

Integrating Technology Acceptance Model And Health Belief Model Factors To Better Estimate Intelligent Tutoring System Use For Surge Capacity Public Health Events And Training, Sarah Matthews Jan 2020

Integrating Technology Acceptance Model And Health Belief Model Factors To Better Estimate Intelligent Tutoring System Use For Surge Capacity Public Health Events And Training, Sarah Matthews

Electronic Theses and Dissertations, 2020-2023

The U.S. public health system is continually challenged by unexpected epidemiological events that pose significant risks to the health of the community and require a commensurate surge in the public health system capacity to stem the spread of the disease. The complexity and even changing nature of funding and surge events drives agencies to innovate in order to maintain and support a competent workforce as well as update, or evolve the knowledge, skills and abilities (KSA) necessary to prevent, mitigate, or even eliminate the health crisis arising from a disease. This research investigates the capability of an agent-based, online personalized …

Go to article

Taking Inventory, Constance Owens Jan 2020

Taking Inventory, Constance Owens

Electronic Theses and Dissertations, 2020-2023

"Taking Inventory" is a biography about my mother, whose life spanned decades filled with hope, heartbreak, loneliness, and adversity. Weaving together micro-essay and prose poetry set at the merger of her adulthood and my childhood, this mixed genre collection examines the many ways her life influenced mine. The triptych structure of the book moves backwards in time, exploring the relationship between my mother and the world she navigated, beginning with the final stages of her life, moving through a turbulent mid-life, and ending with the young woman affected by a world war, an alcoholic father, and a devoutly religious mother. …

Go to article

Two's Accompany: Understanding Acceptance Through Animation, Brian Phinn Jan 2020

Two's Accompany: Understanding Acceptance Through Animation, Brian Phinn

Electronic Theses and Dissertations, 2020-2023

Animation as a medium has broad appeal based on its ability to convey stories in universal ways. This art form bridges cultural barriers that allow relationships to form through shared interests. Music also shares similar traits. Based on the global understanding of music and its history of use in film, the conclusion is the acceptance of different musical tastes can parallel acceptance of differing ideologies. When clashing ideological beliefs cause societal conflict, it is essential to remember that friendships cultivate through commonalities. The purpose of this study is to create an animated short film that presents the story of two …

Go to article

Distributed Multi-Agent Optimization And Control With Applications In Smart Grid, Towfiq Rahman Jan 2020

Distributed Multi-Agent Optimization And Control With Applications In Smart Grid, Towfiq Rahman

Electronic Theses and Dissertations, 2020-2023

With recent advancements in network technologies like 5G and Internet of Things (IoT), the size and complexity of networked interconnected agents have increased rapidly. Although centralized schemes have simpler algorithm design, in practicality, it creates high computational complexity and requires high bandwidth for centralized data pooling. In this dissertation, for distributed optimization of networked multi-agent architecture, the Alternating Direction Method of Multipliers (ADMM) is investigated. In particular, a new adaptive-gain ADMM algorithm is derived in closed form and under the standard convex property to greatly speed up the convergence of ADMM-based distributed optimization. Using the Lyapunov direct approach, the proposed …

Go to article

Patients With A Left Ventricular Device And Factors Affecting Readmission, Diana Pitcher Jan 2020

Patients With A Left Ventricular Device And Factors Affecting Readmission, Diana Pitcher

Electronic Theses and Dissertations, 2020-2023

Patients with a left ventricular assist device have a high rate of hospital readmissions after their index (placement of left ventricular device) discharge. With these devices becoming more common providers of care must understand why this population is being readmitted in order to promote well-being and keep patients out of the hospital. The purpose of this study was to identify and describe characteristics of the hospital readmission. This research study was a retrospective analysis of aggregate data from 2013-2019 with a sample size n = 32. The summary of data was described with descriptive statistics. The data was grouped and …

Go to article

Investigations On The Use Of Hyperthermia For Breast Cancer Treatment, Sreekala Suseela Jan 2020

Investigations On The Use Of Hyperthermia For Breast Cancer Treatment, Sreekala Suseela

Electronic Theses and Dissertations, 2020-2023

Hyperthermia using electromagnetic energy has been proven to be an effective method in the treatment of cancer. Hyperthermia is a therapeutic procedure in which the temperature in the tumor tissue is raised above 42°C without causing any damage to the surrounding healthy tissue. This method has been shown to increase the effectiveness of radiotherapy and chemotherapy. Radio frequencies, microwave frequencies or focused ultrasound can be used to deliver energy to the tumor tissue to attain higher temperatures in the tumor region for hyperthermia application. In this dissertation the use of a near field focused (NFF) microstrip antenna array for the …

Go to article

Study On Comprehensive Mechanical Properties Of Metallic Matrix Cnt Nano-Composites, Shutao Song Jan 2020

Study On Comprehensive Mechanical Properties Of Metallic Matrix Cnt Nano-Composites, Shutao Song

Electronic Theses and Dissertations, 2020-2023

Carbon nanotubes (CNT) have excellent mechanical strengths, electrical conductivity, and thermal conductivity. CNT reinforced metallic nano-composites are viewed as a great candidate to replace traditional alloy materials. It has been shown that CNTs can greatly enhance the strength, thermal conductivity, and electrical conductivity of composites. However, the ductility of composites would deteriorate due to the addition of CNTs if the fabrication or/and processing methods are not improved or well designed. This dissertation investigated (1) the strengthening mechanisms of CNT on metallic matrix, such as mechanical strength and thermal conductivity, and (2) analytical modeling on the strength-ductility trade-off of CNT reinforced …

Go to article

The Dollar General: Continuous Custom Gesture Recognition Techniques At Everyday Low Prices, Eugene Taranta Jan 2020

The Dollar General: Continuous Custom Gesture Recognition Techniques At Everyday Low Prices, Eugene Taranta

Electronic Theses and Dissertations, 2020-2023

Humans use gestures to emphasize ideas and disseminate information. Their importance is apparent in how we continuously augment social interactions with motion—gesticulating in harmony with nearly every utterance to ensure observers understand that which we wish to communicate, and their relevance has not escaped the HCI community's attention. For almost as long as computers have been able to sample human motion at the user interface boundary, software systems have been made to understand gestures as command metaphors. Customization, in particular, has great potential to improve user experience, whereby users map specific gestures to specific software functions. However, custom gesture recognition …

Go to article

Advanced Econometic Models For Modeling Flows: Application To Shared Economy, Bibhas Dey Jan 2020

Advanced Econometic Models For Modeling Flows: Application To Shared Economy, Bibhas Dey

Electronic Theses and Dissertations, 2020-2023

Travel and tourism industry is undergoing transformation with the flourishing of online sharing economy marketplaces such as Bike Share services, Uber/Lyft (for taxi services), Eatwith (for community restaurants), and AirBnB (for accommodation). The current research effort contributes to literature on sharing economy service flow analysis by formulating and estiamting econometric approaches for analyzing frequency variables. The sharing economy alternatives investigated include: (a) accommodation service (AirBnB), (b) bikeshare service (Citi bike, NYC) and (c) ride hailing service (UBER/LYFT/Taxi). In the first part of the dissertation, we develop a copula based negative binomial count model framework to count AirBnB listings at census …

Go to article

Multi-Species Measurements At High Temperatures Using Advanced Mid-Infrared Laser Schemes, Zachary Loparo Jan 2020

Multi-Species Measurements At High Temperatures Using Advanced Mid-Infrared Laser Schemes, Zachary Loparo

Electronic Theses and Dissertations, 2020-2023

High-temperature reacting systems are central to many fields including propulsion, power generation, and transportation. Studying such systems requires the use of experimental facilities such as shock tubes to obtain the relevant high temperature conditions, and non-intrusive diagnostic tools for monitoring parameters of interest in the reaction zone, including temperature and species concentration time-histories. Laser absorption spectroscopy offers high-speed, in-situ measurements of the reacting flow field and provides direct measurements of species concentrations and temperature. Applying absorption spectroscopy via different diagnostic strategies enables tailored measurements of these parameters across a variety of combustion systems for chemical kinetic model refinement and enhancing …

Go to article

Synthesis Of Ruthenium Bipyridine Conjugated Antibiotic For Fluorescence Lifetime Imaging And Spectroscopy Aided Tracking In Citrus, Ryan Parente Jan 2020

Synthesis Of Ruthenium Bipyridine Conjugated Antibiotic For Fluorescence Lifetime Imaging And Spectroscopy Aided Tracking In Citrus, Ryan Parente

Electronic Theses and Dissertations, 2020-2023

Antibiotic treatment of systemic bacterial plant pathogens is an established practice in many crops; however, in citrus it has only recently become available for growers to utilize against Huanglongbing disease. The preliminary efficacy of these treatments is uncertain due to the inability to track their presence in phloem. The need to monitor their movement in planta, especially their presence and translocation in vascular tissue, is a necessary step in clarifying their effectiveness. Previous work has shown the value of Fluorescence Lifetime Imaging (FLIM) in distinguishing between fluorescent probes and plant tissue autofluorescence, which is normally a barrier in photochemical studies …

Go to article

First Prev Next Last