Dissertation Defense Announcements

Candidate Name: Wai-Lun Lam
Title: New version of optimal stopping problem
 April 09, 2024  12:30 PM
Location: Fretwell 315

This dissertation contains several new results concerning Moser-type optimal stopping problems. In the simplest case we consider sequence of independent uniformly distributed points X1, X2, · · · , Xn on the compact Riemannian manifold M and give algorithm for the calculation of Sn = maxτ≤nE[G(Xτ )]where G is a smooth function on M and τ is a random optimal stopping time. Description of the optimal τ depends on the structure of G near points of maximum. For different assumptions on this structure we calculate asymptotics of Sn.

Candidate Name: Marcus Leake
 April 01, 2024  10:30 AM
Location: https://charlotte-edu.zoom.us/j/96306146680?pwd=WlRiNEJZS2FBWjI3a0ZXREcvWTJUdz09

This study explored teacher and student perspectives on mandated school uniforms. Debate exists over the appropriateness of uniforms, with some stakeholders suggesting positive outcomes while others bemoan limits on student expression. This study sought to fill a gap in research specific to middle school uniform use by exploring teachers' and students' perceptions. This research also considered the intersection of gender and diversity issues with uniform policies because these topics are becoming more prominent in the discussion. Four focus groups were conducted, two at a suburban school and two at an inner-city school. Findings suggested that teachers and students at the suburban middle school experienced uniforms more positively than their counterparts in the inner city. Additionally, findings indicated that female students had more negative experiences with uniform policies and their enforcement. From a social identity perspective, this study suggests that the group experience of the same uniform could have a positive or negative impact. When people feel the need for a positive group self, they demonstrate ingroup bias, which could help or hamper the implementation of school uniforms. This research helps bridge the gap in empirical literature within the context of social groups and critical theory to offer recommendations for administrators and policymakers regarding school uniforms in public middle schools. Results can direct further research while raising awareness of issues administrators should address when considering the implementation of a school uniform policy.

Candidate Name: Nicole Godlock
 April 08, 2024  3:00 PM
Location: https://charlotte-edu.zoom.us/j/99717961443?pwd=OXB4dUNJZm1Xc3FlQlVqTVcrU2NLdz09

In the healthcare domain, the development of digital health technologies, including mobile applications, telehealth, wearables, and portals, have created new avenues to deliver patient care, track chronic illnesses, and distribute health information. Digital health technologies allow physicians and patients to interact outside of the traditional care settings; therefore, increasing access to care for disparate populations. Understanding the factors that impact a patient’s decision to adopt digital health technologies is essential to maximizing the Actual Use of digital health technologies and addressing health disparities. This research integrates the Health Belief Model (HBM) and Unified Theory of Acceptance and Use of Technology (UTAUT) to examine technology use behaviors specifically in the context of healthcare. This study evaluates three independent variables – intention to use, Perceived Health Benefit, and Social Influence to determine their impact on Actual Use of technology. This study also investigates how Trust in Technology and eHealth Literacy moderate the relationship between Actual Use of technology and its antecedents. Data from a sample of adults in the United States (N= 293) provides insights into the relationships of the proposed research model.

Candidate Name: Ahmed Almhawes
Title: Academic Acceleration in Saudi Arabia
 April 09, 2024  2:30 PM
Location: SPCD Conference Room 344

Acceleration is one of the best-supported interventions available to gifted education practitioners internationally. However, the acceleration program in Saudi Arabia is still inchoate and could benefit from additional revision. The purpose of this research was to explore Saudi stakeholders’ perceptions regarding their lived experiences with the acceleration program implemented by the Saudi Ministry of Education beginning in 2014. To investigate, I used a qualitative research design and a phenomenological approach. Using semi-structured interviews, 18 Saudi stakeholders were interviewed within six clusters (i.e., three clusters comprising an accelerated gifted student, their parent, and their teacher, plus another three similar clusters with non-accelerated students). Following a thematic analysis method to categorize and synthesize these stakeholders’ perceptions, this approach revealed that Saudi stakeholders believed acceleration as a program was effective for Saudi gifted students. They perceived it as a convenient option, well aligned with gifted students’ characteristics, and as an appropriate recognition of these students’ superiority and dedication. The program was seen as the best available gifted program option in the Saudi context. Participants commended the acceleration intervention for positively affecting gifted students' academic performance. They believed that it provided challenging learning materials, fulfilled academic needs, and led to high grades, intelligence quotient (IQ) scores, and national standardized test scores. They also highlighted the importance of gaining advanced skills after completion. However, stakeholders also criticized the regulations and nomination procedures for the Saudi acceleration program, stating that the procedures were vague, not transparent, and unfair in geographical and other ways. All stakeholders also described a lack of awareness and preparation among teachers, parents, and students. Differences of opinion regarding the impact of this acceleration intervention on the social and emotional status of program participants also reveals contradictions. While some positive aspects included successful adaptation, balancing old and new friendships, maturity, and improved gifted characteristics, other responses mentioned potential negative impacts like anxiety and the pressure of high expectations from the students’ community. In general, Saudi stakeholders believed that the acceleration program positively impacts gifted students' future lives by enabling them to finish school earlier and more efficiently. Successful acceleration also led to scholarships, participation in national programs, and scientific trips, benefiting both society and these gifted students. Furthermore, the discussion revealed implications for practices and policies to improve the acceleration program’s regulation and implementation. Based on these findings, several future research directions are suggested.

Candidate Name: Sabeeh Irfan Ahmad
Title: Experimental ​ Study of ​Avalanche ​Ionization in the ​Femtosecond ​ Breakdown of ​Atomic ​Layered ​Materials
 April 08, 2024  11:00 AM
Location: Grigg Hall Room 131

The engine of modern society is fueled by information, and the desire to obtain, process and relay it ever more quickly is motivation for scientists to dig deeper into pathways that enable this endgame. The implementation of ever-quicker computer processors, optical fiber-based communications, and Light Radar (LiDar) for climate studies are a small subset that illustrate how ubiquitous the applications of optics are. In this context, the study of 2D materials (2DMs) is important due to the fascinating properties they exhibit that could lead to a plethora of future opto-electronic applications that extend beyond what silicon alone can provide. The story began with graphene due to its high conductivity and tensile strength, but due to the difficulty of switching its conductivity, applications in transistors is limited, and other materials such as the transition metal dichalcogenides (TMDs) MoS2 and WS2, which exhibit a bandgap transition from indirect to direct when going from bulk to monolayer, are being explored. The wide bandgap semiconductor hexagonal boron nitride (hBN) has also been piquing interest. The presence of room-temperature stable excitons detected via various spectroscopies suggests applicability in mainstream field-effect transistors, and current industry direction towards so-called ‘nanosheet’ and ‘nano-wire’ channel transistors serve as prime examples of the relevant applicability of such 2D materials. Quantum computing and valley-tronic applications have also been reported [5], making this class of material exciting to study.
When material dimensions are reduced to the single atomic layer (‘monolayer’) limit, fast carrier dynamics become important that can only be investigated by even faster phenomena i.e., femtosecond ‘ultrafast’ laser pulses. When exposed to intense electric fields, several processes can occur; multiphoton absorption (MPA) which utilizes multiple photons to promote a single charge carrier to the conduction band (CB), tunneling ionization (TI) in which the laser field modifies the inter-atomic potential and allows CB access via tunneling, and avalanche ionization (AI) where inter-carrier impact causes ionization. Together, these strong-field ionization (SFI) processes are subject to significant research effort. If SFI-induced excited carrier populations exceed a threshold, damage occurs via a non-thermal ‘ablation’ process typically used for cutting and patterning.
The objective of this work was to explore the ultrafast optical dielectric breakdown (ODB) behavior of 2DMs such as MoS2, WS2, and hBN. The work involves an investigation of the etalon interference effect that causes differences in the ablation threshold fluence for the same material when placed on different substrates, differences in threshold fluence between different 2DMs, as well as an exploration of laser-induced defects added when multiple ultrafast pulses are incident on the material. ODB for the wide bandgap insulator hBN is also demonstrated and characterized using various imaging modalities and spectroscopies for the first time. Through the findings presented in this work, we begin to unravel some aspects of the nature of ablation, particularly the dominance of avalanche ionization as the key carrier generation mechanism in the ODB process in 2D materials. We also establish femtosecond laser direct writing as a useful tool for the nanopatterning of such 2DMs.

Candidate Name: Deondra S. Gladney-Campbell
Title: A Meta-Analysis of Culturally Sustaining Instructional Effects on African American Students’ Academic and Behavioral Outcomes
 April 08, 2024  9:00 AM
Location: Zoom https://charlotte-edu.zoom.us/j/91450796881

Researchers have identified that inequitable learning experiences for African American students have negatively impacted their educational outcomes in the United States, and culturally sustaining practices offer great promises in supporting African American students. This meta-analysis investigated the effectiveness of culturally sustaining practices on African American students’ academic and behavioral outcomes. This study built on prior attempts to synthesize multiple definitions of culturally sustaining practices with recommendations from the literature aimed directly at African American students. In this dissertation, I first used the existing synthesis to establish a theoretical framework with an operational definition of culturally sustaining practices for African American students (CSPAAS). I then conducted a systematic review to identify group design studies aligned with the components of the CSPAAS framework. Effect sizes were extracted from each individual study and a random effects model was employed to determine the overall effectiveness of CSPAAS interventions. Additionally, I evaluated the included studies for methodological rigor using the Council for Exceptional Children (CEC, 2014, 2023) quality indicators to determine the extent to which CSPAAS interventions could be identified as evidence-based practices. Results revealed CSPAAS academic interventions were highly effective (n = 17; g = 1.01) and CSPAAS behavioral interventions were moderately effective (n = 5; g = 0.5). The CSPAAS practices for both academic and behavioral interventions also met CEC (2014, 2023) criteria to be categorized as evidence-based practices. Implications for future research are discussed.

Candidate Name: Courtney Skipper
 April 03, 2024  9:00 AM
Location: CHHS 102

Patients requiring admission to the Trauma Intensive Care Unit (TICU) represent some of
the most critically ill and complex cases within intensive care. These patients, often suffering
from significant trauma to vital areas, may necessitate prolonged enteral feeding, frequently
leading to the insertion of gastrostomy tubes. Despite the critical nature of gastrostomy tube
management for patients with severe trauma and the need for enteral feeding, there is a gap in
knowledge and confidence in this area. This gap necessitates targeted educational programs to
improve patient outcomes. This quality improvement project focused on the nursing staff in the
Trauma Intensive Care Unit (TICU) at a large academic medical center. The nurses received a
comprehensive education module developed according to Lippincott standards, which covered
the different types of gastrostomy tube types, nursing interventions, and documentation practices.
The module included a didactic component and hands-on practice with gastric tube models. A
pre-and post-test knowledge check was conducted to evaluate the learning outcomes. All 43
TICU staff registered nurses at the facility participated. After the educational module's
implementation, significant improvements were observed in nursing staff knowledge regarding
gastrostomy tubes. The median score for the pre-test was 70%, increasing to 100% on the post-
test. Wilcoxon sign-rank test showed a statistically significant difference between pre- and post-
test scores, z = 5.207, p < .001. The results demonstrate the effectiveness of the education
module in improving TICU nurses' knowledge of gastric tube care.

Candidate Name: Elaine Gorom
Title: Multiscale Modeling for Crystalline Materials: A Comprehensive Study in Statics and Dynamics
 April 04, 2024  2:30 PM
Location: Fretwell 315

Computational materials science plays a crucial role in advancing new and improved materials. To leverage the advantages of local and nonlocal methods and aid in the advancement of predictive capabilities for materials, multiscale models have been introduced. Many such methods have been proposed to overcome computational challenges in accuracy and efficiency. In this work, I begin by presenting a review of some multiscale methods for crystalline modeling to provide context for this dissertation.

Together with my advisor Dr. Xingjie Helen Li, we explore the static behavior of a bottom-up nonlocal-to-local coupling method, Atomistic-to-Continuum coupling, and explore the dynamic behavior of a nonlocal method, Peridynamics, to explore a bimaterial interface.

Inspired by the blending method developed by \cite{Seleson2013} for nonlocal-to-local coupling, we create a symmetric and consistent blended force-based Atomistic-to-Continuum (AtC) scheme for one-dimensional atomistic chains. AtC coupling schemes have been introduced to utilize the accuracy of atomistic models near known defects and the computational efficiency of continuum models elsewhere. The conditions for the well-posedness of the underlying model are established by analyzing an optimal blending size and blending type to ensure the stability of the $H^1$ seminorm for the blended force-based operator. We present several numerical experiments to test and confirm the theoretical findings.

Then, we create a Peridynamics-to-Peridynamics scheme to model a bimaterial bar in one dimension. Peridynamics (PD) naturally allows for the simulation of crack propagation in its model due to its use of integro-differentials and time derivatives instead of the spatial derivatives typical of classical models. Although PD can be computationally intensive, its ability to accurately model fracture behavior, especially at material interfaces, makes it a valuable tool for achieving high accuracy in simulations, especially due to the susceptibility of fracture where differing materials meet. We prove the conservation laws, derive the dispersion relation, and estimate the coefficient of reflection near the interface for this nonlocal-to-nonlocal problem. We seek an optimal nonlocal interaction kernel in the governing equation for the cross-material interaction to reduce spurious artifacts when the kernel is assumed to be constant.

Lastly, I discuss potential future development in Atomistic-to-Continuum coupling and Peridynamics.

Candidate Name: Amber Greenwood
Title: “I’m Just So Busy:” The Creation of a Busyness Façade as an Impression Management Tactic
 April 09, 2024  2:30 PM
Location: Cone 110

Busyness, or how busy someone is, has increasingly become a topic of conversation in day-to-day life. Research has previously explored how people use their time and how people perceive their available time, or lack thereof, but there is no clear answer as to why people tell others that they are busy and what it is they are trying to accomplish by doing so. Drawing on impression management research, this paper proposes that people signal to others that they are busy so that the audience has a positive impression of them. The concept of the busyness façade is introduced, which includes behaviors and verbal statements that are intentionally enacted by individuals to signal to others that they have a lot to do or limited available time. Exactly how and why people engage in this busyness façade is explored in two studies using semi-structured interviews and an online, vignette survey. Overall, evidence is found for the existence of busyness façades and a better understanding of how people display busyness is gained, but the studies are unable to identify a clear motive for why busyness façades would be used as an impression management tactic. Additional findings and research directions are discussed.

Candidate Name: Hussein Hazazi
Title: Understanding and Improving the Usability, Security, and Privacy of Smart Locks from the Perspective of the End User
 April 08, 2024  12:30 PM
Location: Zoom https://charlotte-edu.zoom.us/j/91075751264?pwd=dnhpbjBncWRSdTJ1cGlKSzZ5ZVk2dz09

Over the past two decades, the Internet of Things (IoT) has seen a significant expansion in both the sophistication and variety of its applications. These applications span several domains, including enhancing and automating services in healthcare, advancing smart manufacturing processes, and elevating home living standards through smart home technologies. These technologies empower individuals with greater control over their home appliances. Smart locks are smart home devices that were introduced as replacements for traditional locks. Smart locks, designed to go beyond the basic functionality of traditional locks by offering additional features, have seen a surge in market growth and competitiveness. According to the Statista Research Department, it is projected that the global market for smart locks will surpass four billion dollars by 2027.
A number of studies have examined end users' concerns, needs, and expectations regarding smart homes in general. However, little research has been conducted to examine these aspects of the smart lock in particular. To address this gap, we conducted a series of user studies that aim to elucidate how smart locks are integrated and interact within smart home environments, focusing on user interactions both with the locks themselves and when they are part of broader automation scenarios. This dissertation contributes to a deeper understanding of smart lock technology from a user-centric viewpoint. It offers insights into user motivations, concerns, and preferences regarding smart lock usage and automation. It also highlights the importance of balancing convenience and security, the pivotal role of trust, and the complexities of integrating smart locks into broader smart home systems.