Digital Commons Network^™

Solid Materia And Multiphase Detonations Wave Dynamics In A Rotating Detonation Engine, Ian Dunn

Electronic Theses and Dissertations, 2020-2023

Coal dust explosions can be hazardous; however, they can also generate a significant rise in stagnation pressure if adequately harnessed. Rotating detonation engine combustors seek to take advantage of the stagnation pressure rise phenomenon in a more sustained and controlled manner via confinement to a physical annulus, leading to increased overall thermodynamic efficiency. This investigation presents an analysis of detonations fueled by Carbon Black, a solid particulate consisting of virtually pure carbon molecules and lean Hydrogen-Air mixtures. As was previously realized with the addition of Carbon Black, an increase of operability limits and detonation velocities over that of a pure …

Algorithms And Lower Bounds For Ordering Problems On Strings, Daniel Gibney

Electronic Theses and Dissertations, 2020-2023

This dissertation presents novel algorithms and conditional lower bounds for a collection of string and text-compression-related problems. These results are unified under the theme of ordering constraint satisfaction. Utilizing the connections to ordering constraint satisfaction, we provide hardness results and algorithms for the following: recognizing a type of labeled graph amenable to text-indexing known as Wheeler graphs, minimizing the number of maximal unary substrings occurring in the Burrows-Wheeler Transformation of a text, minimizing the number of factors occurring in the Lyndon factorization of a text, and finding an optimal reference string for relative Lempel-Ziv encoding.

Novel Liquid Crystal Photonic Devices Enabled By Liquid Crystal Alignment Engineering, Ziqian He

Electronic Theses and Dissertations, 2020-2023

Liquid crystals (LCs) are self-assembled soft materials composed of certain anisotropic molecules with orientational orders. Their widespread applications include information displays and photonic devices, such as spatial light modulators for laser beam steering and tunable-focus lens, where achieving desired LC alignment is pivotal. In general, LC alignment is influenced by several factors, including chemical bonding, dipolar interactions, van der Waals interactions, surface topographies, and steric factors. Here, we focus on three alignment techniques for aligning rod-like LC molecules and highlights the photonic devices enabled by these techniques: 1) Two-photon polymerization direct-laser writing-induced alignment, 2) Weigert effect-based reversible photoalignment, and 3) …

Mechanically Reconfigurable Materials And Devices Based On Two-Dimensional Transition Metal Dichalcogenide Layers, Emmanuel Okogbue

Electronic Theses and Dissertations, 2020-2023

The recent advances in electronic technologies are geared towards a combination of continued miniaturization in device components and their integration onto unconventional platforms. These efforts are aimed towards achieving electronic devices with various form factors and novel functionalities which are unattainable from traditional devices. Among these envisioned 'futuristic' technologies, electronic devices which are mechanically reconfigurable and operable under harsh operational conditions in the form of stretching, twisting and folding offer tremendous amount of unparalleled opportunities. This dissertation studies two-dimensional (2D) transition metal dichalcogenide (TMDs), a distinct class of materials with peculiar optical, electrical and mechanical properties for mechanically reconfigurable electronics. …

Analyzing The Blockchain Attack Surface: A Top-Down Approach, Muhammad Saad

Electronic Theses and Dissertations, 2020-2023

Blockchains enable secure asset exchange in a distributed system, thereby facilitating innovative applications such as cryptocurrencies and smart contracts. Although the cryptographic constructs of blockchains are highly secure, however, their practical deployments are vulnerable to various attacks due to their application-specific policies, and their peer-to-peer (P2P) network intricacies. In this work, we take a top-down approach towards exploring those attacks, starting with the application-specific abuse of blockchain-based cryptocurrencies and concluding with the network conditions that violate the blockchain consistency. In the top-down approach, we first analyze the application-specific abuse of blockchain-based cryptocurrencies by uncovering (1) covert cryptocurrency mining in the …

Help In The Time Of Covid: Informational, Emotional, And Instrumental Support Among Graduate Students During A Pandemic, Teanna Staser

Electronic Theses and Dissertations, 2020-2023

This study examined graduate students' experiences with social support in relation to stress and uncertainty during the COVID-19 global pandemic. Graduate students as a population have significant levels of stress and uncertainty which may have negative effects on their lives and academic experiences. Graduate students often utilize social support as a way to cope with or mitigate the effects of stress and uncertainty. This qualitative study consisted of six focus groups, ranging from three to six participants, total of 22 participants, who were found using a purposeful snowball sampling method. The participants were masters and doctoral level students in communication …

When Fairness Fails: Using Territorial Behaviors To Cope With Uncertainty, Christopher Stein

Electronic Theses and Dissertations, 2020-2023

Research on territorial behaviors in organizations is an emerging field (Brown, Crossley, & Robinson, 2014). Current theoretical approaches to territoriality rely heavily on a psychological ownership perspective; however, there is a wealth of theory organizational scholars can integrate from other disciplines (Altman, 1975; Ardrey, 1965; Brown, Lawrence, & Robinson, 2005). The purpose of this dissertation is to integrate an evolutionary perspective into organizational scholarship to explore new antecedents of territoriality. This research draws upon uncertainty management theory to hypothesize a moderated-mediated model predicting territorial behaviors. A measurement instrument is developed to test territoriality and findings from a three-wave field study …

Low-Profile Wireless Passive Temperature Sensors, Ectis Velazquez

Electronic Theses and Dissertations, 2020-2023

This thesis explores design challenges and promising solutions for temperature sensors for high temperature environments such as combustion turbines. To survive this high temperature environment of over 1000 °C the sensors are required to be robust in their electrical and mechanical properties. Wire connections for these high temperature environments are a complex problem due to the physical limitations of most materials at those high temperatures. In this thesis, robust ceramic sensors based on microwave resonators are demonstrated for high temperature environments, with some studies into optimizing the techniques used to measure them, as well as the distance at which their …

"I Have My Coven Now": Transgender Experience In The Central Florida Pagan Community, Alison Whitmore

Electronic Theses and Dissertations, 2020-2023

This thesis analyzes Transgender experience and dynamics in the Pagan community of Central Florida. Religion plays an important role as part of social structure for many people in the United States. It can also be a source of strife and conflict between culture groups and within cultures. In the US, predominant religious traditions stem from monotheistic Abrahamic faiths (Christianity, Judaism, and Islam); however, Wicca, a Neo-Pagan polytheistic religion, is practiced by a small but growing number of people. Based on nearly one year of ethnographic engagement with the Central Florida Wiccan community, this study presents an analysis of participants experiences …

Couples With Infertility: The Influence Of Quality Of Life, Relationship Satisfaction, Resilience, Depression, And Shame, Nikole Wilson

Electronic Theses and Dissertations, 2020-2023

The purpose of this study was to investigate the directional relationship between fertility related quality of life, relationship satisfaction, resilience, depression, and shame amongst individuals and couples with infertility. This study tested the hypothesized directional relationship that individuals and couples with infertility (N = 556) with a greater level of fertility related quality of life (FertiQol) would have (a) increased relationship satisfaction (CSI), (b) increased resilience (CD-RISC), (c) decreased depression (PROMIS), and (d) decreased shame (FSCRS), through structural equation modeling (SEM) and the actor partner interdependence model (APIM). Also, the researcher tested the dyadic influence of fertility related quality of …

Robust Acceleration Of Data-Centric Applications Using Resistive Computing Systems, Baogang Zhang

Electronic Theses and Dissertations, 2020-2023

With the accessible data reaching zettabyte level, CMOS technology is reaching its limit for the data hungry applications. Moore's law has been reaching its depletion in recent studies. On the other hand, von Neumann architecture is approaching the bottleneck due to the data movement between the computing and memory units. With data movement and power budgets becoming the limiting factors of today's computing systems, in-memory computing using emerging non-volatile resistive devices has attracted an increasing amount of attention. A non-volatile resistive device may be realized using memristor, resistive random access memory (ReRAM), phase change memory (PCM), or spin-transfer torque magnetic …

Biophysical Analysis Of The Structure And Aggregation Of Amyloid Beta Peptide, Faisal Abedin

Electronic Theses and Dissertations, 2020-2023

Alzheimer's disease (AD) is the major cause of dementia and is characterized by neuronal death and brain atrophy. The amyloid ß (Aß) peptide is tightly associated with neuronal dysfunction during AD, but the molecular mechanism underlying the neurotoxic effect of Aß is poorly understood. Extracellular fibrillar deposits (plaques) of Aß were initially believed to be the cause of AD, but currently there is overwhelming evidence that the prefibrillar Aß oligomers are the major toxic entities. Structural characterization of Aß oligomers and fibrils is important for understanding the structural features determining the toxic potency of the peptide. This project has studied …

Identifying Biomarkers Of Alzheimer's Disease From The Dakhleh Oasis Kellis 2 Cemetery Using Icp-Ms, Emily Barron

Electronic Theses and Dissertations, 2020-2023

Alzheimer's disease is a prevalent disease that affects roughly 5.4 million individuals each year (Fisher et al., 2018). Understanding the prevalence of Alzheimer's disease within the bioarchaeological record can help anthropologists gain an understanding of a population's health while also understanding the potential social ramifications. Trace element analysis is a valuable tool that allows bioarchaeologists to gain insight into individuals' health and development within the context of the past. In bioarchaeological studies, hair analysis has been used to map the nutritional status and migration patterns of individuals of past peoples, with recent studies focusing on disease prevalence. Analysis of hair …

The Bikini Line: Race, Gender, And Embodiment In Texas Beauty Pageants, Chelsea Belanger

Electronic Theses and Dissertations, 2020-2023

In 2019, for the first time in history, Miss America, Miss USA, Miss Teen USA, and Miss Universe were all Black women. However, in Texas pageantry, where 12 former state titleholders have become Miss America or Miss USA are from, racial representation is scant. Since their inception in 1937 and 1952, only three Black women have won title of Miss Texas America and two Black women have been crowned Miss Texas USA. This study analyzes the motives for competing in Texas beauty pageants, experiences of preparing and competing, and the perceptions of race and racial inequalities among racially and ethnically …

Smart Parking Systems: Reviewing The Literature, Architecture And Ways Forward, Can Biyik, Zaheer Allam, Gabriele Pieri, Davide Moroni, Muftah O' Fraifer, Eoin O' Connell, Stephan Olariu, Muhammad Khalid

Computer Science Faculty Publications

The Internet of Things (IoT) has come of age, and complex solutions can now be implemented seamlessly within urban governance and management frameworks and processes. For cities, growing rates of car ownership are rendering parking availability a challenge and lowering the quality of life through increased carbon emissions. The development of smart parking solutions is thus necessary to reduce the time spent looking for parking and to reduce greenhouse gas emissions. The principal role of this research paper is to analyze smart parking solutions from a technical perspective, underlining the systems and sensors that are available, as documented in the …

A Survey Of Enabling Technologies For Smart Communities, Amna Iqbal, Stephan Olariu

Computer Science Faculty Publications

In 2016, the Japanese Government publicized an initiative and a call to action for the implementation of a "Super Smart Society" announced as Society 5.0. The stated goal of Society 5.0 is to meet the various needs of the members of society through the provisioning of goods and services to those who require them, when they are required and in the amount required, thus enabling the citizens to live an active and comfortable life. In spite of its genuine appeal, details of a feasible path to Society 5.0 are conspicuously missing. The first main goal of this survey is to …

Extraction And Evaluation Of Statistical Information From Social And Behavioral Science Papers, Sree Sai Teja Lanka, Sarah Rajtmajer, Jian Wu, C. Lee Giles

Computer Science Faculty Publications

With substantial and continuing increases in the number of published papers across the scientific literature, development of reliable approaches for automated discovery and assessment of published findings is increasingly urgent. Tools which can extract critical information from scientific papers and metadata can support representation and reasoning over existing findings, and offer insights into replicability, robustness and generalizability of specific claims. In this work, we present a pipeline for the extraction of statistical information (p-values, sample size, number of hypotheses tested) from full-text scientific documents. We validate our approach on 300 papers selected from the social and behavioral science literatures, and …

See-Trend: Secure Traffic-Related Event Detection In Smart Communities, Stephan Olariu, Dimitrie C. Popescu

Computer Science Faculty Publications

It has been widely recognized that one of the critical services provided by Smart Cities and Smart Communities is Smart Mobility. This paper lays the theoretical foundations of SEE-TREND, a system for Secure Early Traffic-Related EveNt Detection in Smart Cities and Smart Communities. SEE-TREND promotes Smart Mobility by implementing an anonymous, probabilistic collection of traffic-related data from passing vehicles. The collected data are then aggregated and used by its inference engine to build beliefs about the state of the traffic, to detect traffic trends, and to disseminate relevant traffic-related information along the roadway to help the driving public make informed …

Detecting Incentivized Review Groups With Co-Review Graph, Yubao Zhang, Shuai Hao, Haining Wang

Computer Science Faculty Publications

Online reviews play a crucial role in the ecosystem of nowadays business (especially e-commerce platforms), and have become the primary source of consumer opinions. To manipulate consumers’ opinions, some sellers of e-commerce platforms outsource opinion spamming with incentives (e.g., free products) in exchange for incentivized reviews. As incentives, by nature, are likely to drive more biased reviews or even fake reviews. Despite e-commerce platforms such as Amazon have taken initiatives to squash the incentivized review practice, sellers turn to various social networking platforms (e.g., Facebook) to outsource the incentivized reviews. The aggregation of sellers who …

Accuracy Of Implant Placement Utilizing Stereolithographic Guides Printed With And Without Cross-Arch Stabilization Struts, Caitlin Libby Dds

Graduate Theses, Dissertations, and Problem Reports (ETD)

Objectives: The purpose of this study was to assess the accuracy of implant placement using stereolithographic guides printed with and without stabilization struts by comparing the post-operative position to the planned implant position.

Methods: A pre-operative cone-beam computed tomography (CBCT) of a drillable maxillary model was obtained and data was uploaded into coDiagnostiX for preoperative planning. The implant position was planned in an edentulous space of #5 using a 3.3x10mm Bone Level Tapered (BLT) implant (Straumann). Ten surgical guides were designed utilizing a stabilization strut (Group A), while ten guides were designed without the stabilization strut (Group B). Twenty guides …

Demystifying Remote Research In Anthropology And Area Studies, Kaitlyn Ugoretz

Asia Pacific Perspectives

Physically cut off from locations and archives central to our work due to restrictions in response to the global COVID-19 pandemic, area studies scholars must reimagine what constitutes rigorous and responsible research in their respective disciplines. The practice of remote research, however, is not a new one. Digital ethnography, an admittedly niche subdiscipline of anthropology, has long been grappling with the issues of how to value and conduct remote research. This essay explores a number of misconceptions regarding digital and remote research that may aid in contextualizing and coming to terms with the anxieties the broader scholarly community faces. I …

Using The Very Short Form Of The Children’S Behavior Questionnaire For Spanish-Speaking Populations In Low- And Middle-Income Countries: A Psychometric Analysis Of Dichotomized Variables, Elsa Lucia Escalante-Barrios, Sonia Suarez Enciso, Samuel P. Putnam, Helen Raikes, Sergi Fàbregues

Department of Child, Youth, and Family Studies: Faculty Publications

While the psychometric properties of the Spanish version of the Very Short Form of the Children’s Behavior Questionnaire (CBQ-VSF) have been assessed in the US and Europe in samples composed of middle- and high-income parents with high levels of education, no studies have tested the instrument in low-income Spanish-speaking populations living in low- and middle- income countries. To fill this gap, our cross-sectional study assessed the psychometric properties of the Spanish version of the CBQ-VSF version in a sample of 315 low-income and low-educated parents with preschool children living in the Caribbean Region of Colombia. While our findings revealed problems …

Teacher Questioning Practices In Early Childhood Science Activities, Erin Hamel, Yuenjung Joo, Soo-Young Hong, Anna Burton

Department of Child, Youth, and Family Studies: Faculty Publications

This study explores teachers’ use of questioning during collaborative science exploratory activities. We classified a total of 755 questions across 14 preschool science lessons implemented by four teachers by type (open- or closed-ended) and content (science- or non-science-related) while also recording the intended recipient. Results revealed that, overall, teachers primarily asked closed-ended questions to children during preschool science activities. While closed-ended questions outnumbered open-ended, science-related questions were more likely to be open-ended questions. We noticed this trend whether the teacher directed the question to a group of children or an individual child. Gender of the child recipient was also explored …

Food Program Participation Influences Nutrition Practices In Early Care And Education Settings, Bethany D. Williams, Susan B. Sisson, Irene Padasas, Dipti Dev

Department of Child, Youth, and Family Studies: Faculty Publications

Objective: To determine differences by Child and Adult Care Food Program (CACFP) participation on nutrition requirements and best practices and barriers to implementing both in early care and education programs (ECEs) stratified by context (centers vs home-based ECEs).

Design: Cross-sectional survey.

Setting: Three-thousand and fourteen licensed Nebraska ECEs in 2017.

Participants: One-thousand three hundred forty-five ECEs.

Main Outcome Measures: Director-reported nutrition practices in classrooms serving children aged 2-5 years (8 requirements for foods served, 5 best practices for foods served, and 14 best practices for mealtime behaviors).

Analysis: Chi-square analysis adjusted for multiple comparisons.

Results: Of the sample, 86.8% participated …

Improving Breastfeeding Environments And Feeding Practices In Family Child Care Homes With The Go Nap Sacc Program, Kara Kohel, Holly Hatton-Bowers, Natalie A. Williams, Dipti Dev, Donnia Behrends, Emily Hulse, Zainab Rida, Holly Dingman, Danae Dinkel, Liz Gebhart

Department of Child, Youth, and Family Studies: Faculty Publications

Purpose: Breastfeeding and responsive feeding are important practices that support the health of infants and women. In the United States, breastfeeding continuation rates remain lower than recommended, and working women face additional challenges with breastfeeding continuation. Providers in a family child care setting are uniquely positioned to support and provide important resources to families in their breastfeeding and infant feeding practices.

Methods: The Go NAP SACC program was designed to improve the nutrition and physical activity environments and practices in child care settings serving infants and young children. This evaluation focuses on Breastfeeding and Infant Feeding in Nebraska Family Child …

Competency-Based Training In The Supervision Of Relational Telemental Supervision, Paul Springer, Richard Bischoff, Nathan C. Taylor, Vanessa Neuhaus, Cassandra Leow

Department of Child, Youth, and Family Studies: Faculty Publications

Supervision has long been considered essential to developing effective mental health practice, especially among COAMFTE accredited training programs. But with telemental health rapidly being accepted as a standard treatment medium for couple and family therapy, there is little guidance about how to supervise clinicians who are engaged in telemental health practice. This paper presents an important step toward increasing the effectiveness of the supervision of therapists who are delivering relational therapies online through the identification of relational competencies unique to this delivery medium. These competencies have been adopted and integrated into a COAMFTE accredited master's degree program that has been …

Psychological Distress Prevalence And Associated Stressors And Supports Among Urban-Displaced Congolese Adults In Kenya, Julie A. Tippens, Holly Hatton-Bowers, Ryan Honomichl, Lorey Wheeler, Helen M. Miamidian, Kirstie L. Bash, Michelle C Howell Smith, Dulo Nyaoro, J. Joshua Byrd, Samuel E. Packard, Nicolette I. Teufel-Shone

Department of Child, Youth, and Family Studies: Faculty Publications

Background: There is limited understanding of the prevalence of psychological distress and associated stressors and supports among displaced adults in low- and middle-income first asylum countries.

Method: This article reports the findings of a cross-sectional study. We recruited 245 Congolese adults (18–80 years) residing in Nairobi, Kenya using snowball sampling. Data were collected using an interviewer-administered questionnaire consisting of sociodemographic characteristics, the Self-Reporting Questionnaire (SRQ-20), and a locally developed stressors and supports survey. We used multivariable logistic regression to examine associations among sociodemographic, stressor, and support variables and the likelihood of experiencing psychological distress.

Results: More than half of the …

Supporting Children’S Healthy Development During Mealtime In Early Childhood Settings, Adrien D. Malek‑Lasater, Kyong‑Ah Kwon, Diane M. Horm, Susan B. Sisson, Dipti Dev, Sherri L. Castle

Department of Child, Youth, and Family Studies: Faculty Publications

The purpose of this study was to examine the frequency of and relationship between responsive feeding practices used during early childhood education (ECE) mealtimes and high-quality teaching practices and teacher characteristics. We found variation in teachers’ use of responsive feeding practices. Teachers were more often observed using role modeling than supporting eating self-regulation. Programs that implemented family style meal service had a generally higher use of responsive feeding practices. Overall, we found positive associations between high-quality teaching practices and responsive feeding practices. Teachers’ Head Start status was associated with teaching practices and role modeling during mealtime. Teachers’ education and salary …

Strengthening The Quality Of Preschool, Childcare, And Parenting, Soo-Young Hong, Holly Hatton-Bowers, Lisa Knoche

Department of Child, Youth, and Family Studies: Faculty Publications

Early childhood is a critical period during which children learn to regulate and manage emotions and actions, develop and maintain social relationships, and interact effectively with others (Scott-Little, Kagan, & Frelow, 2006). Children who know how to use appropriate behavioral and emotional strategies and effectively interact with others are more likely to develop positive relationships and be accepted by peers later on (Odom, McConnell, & Brown, 2008). Emotional well-being and competence is one of the key areas of development that goes through significant changes over the early childhood period (Hyson, Copple, & Jones, 2006; Keane & Calkins, 2004), and thus, …

Mealtime Emotional Climate And Child Health: A Systematic Review, Jasmin Smith, Jaclyn A. Saltzman, Dipti Dev

Department of Child, Youth, and Family Studies: Faculty Publications

Background: Positive mealtime emotional climate (MEC) has been linked to better nutrition, psychosocial, literacy and academic outcomes, and fewer behavior problems. However, MEC has been defined in a variety of ways across studies, limiting the ability to synthesize findings and plan future research.

Objective: To identify which child characteristics are associated with MEC and to determine how previous studies have measured MEC.

Methods: We searched three databases (1980–2020) for peer-reviewed articles measuring MEC. Inclusion criteria required at least one child-level outcome related to physical, nutritional, or developmental health; children aged 0–18 years old; and quantitative data using cohort, case-control, intervention, …