Digital Commons Network^™

The Moderating Role Of Experiential Avoidance Between Child-Caregiver Dynamics And Stem Motivation, Dylan L. Harrell

Doctoral Dissertations

The National Academy of Sciences released a report that discussed the increased need to improve interest and retention of Science, Technology, Engineering, and Math (STEM) careers in the United States. Early childhood factors within one’s family plays an essential role in the process of career decision making, self-concept, and vocational identity. The current study examined the relationship experiential avoidance has on early family dynamics (i.e., family environment, differentiation of self, attachment, and perceived parenting) and perceived motivation in STEM. A total of 231 participants currently enrolled in a Southern University taking a STEM course (Psychology, Biology, Social Science, Computer Science, …

A Comparative Study Of Mono-Stable And Bi-Stable Magnetic Spring Based Energy Harvesters, Hieu Tri Nguyen

Doctoral Dissertations

Continuous advancements in electronics manufacturing have resulted in the widespread use of low-power sensors, necessitating the development of energy harvesters capable of generating electric power from abundant and free energy sources such as ambient vibrations. A rising interest in energy harvesting technology inspires the work discussed herein using magnetic interactions to target nonlinear energy harvesting, which is compatible with ambient vibration energy sources with a broad frequency spectrum and particularly rich in low frequencies. This research aimed to look into a magnetic-levitation-based vibration energy harvester that could be tuned from a mono-stable to a bi-stable configuration. An oscillating magnet is …

What's The Beef With Veg*Ns: A Mixed Method Approach To Anti-Veg*N Stigma, Caitlin M. Mercier

Doctoral Dissertations

Despite veg*n scholarship within psychological science, much of this research examined anti-veg*n attitudes amongst non-veg*ns complemented with scarce research on the impact of anti-veg*n stigma and experiences of veg*ns. Underpinned by critical feminist framework with a phenomenological approach, the present study, a convergent mixed method design, examined the relationship between anti-veg*n stigma and multicultural awareness among 165 non-veg*ns and explored the experiences of 13 veg*ns in the context of stigma. Path analysis revealed that multicultural awareness and attitudes towards those with different dietary habits (e.g., veg*n diets, p. 19) was negatively associated with attitudes towards vegans. Additionally, path analysis revealed …

Quantification Of Hydrologic Response To Forest Disturbance In Western U.S. Watersheds, Sara A. Goeking '92

Doctoral Dissertations

Forested watersheds produce more than half of the water supply in the United States. Forests affect how precipitation is partitioned into available water versus evapotranspiration. This dissertation investigated how water yield and snowpack responded to forest disturbance following recent disturbances in western U.S. forests during the period 2000-2019.

Chapter 2 systematically reviewed 78 recent studies that examined how water yield or snowpack changed after forest disturbances. Water yield and snowpack often increased after disturbance, but decreased in some circumstances. Decreased water yield was most likely to occur following disturbances that did not remove the entire forest canopy. It was also …

Semiparametric Estimation With Clustered Right Censored Data Via Multivariate Gaussian Random Fields, Fathima Zahra Sainul Abdeen

Doctoral Dissertations

Consider a fixed number of clustered areas identified by their geographical coordinate that are monitored for the occurrences of an event such as pandemic, epidemic, migration to name a few. Data collected on units at all areas include time varying covariates and other environmental factors that may affect event occurrences. The event times in every area can be independent. They can also be correlated with correlation between two units induced by an unobservable frailty. In both cases, the collected data is considered pairwise to account for spatial correlation between all pair of areas. The pairwise right censored data is probit-transformed …

Using Coherence And Interference To Study The Few Body Dynamics In Simple Atomic Collisions Systems, Sujan Bastola

Doctoral Dissertations

"Atomic Collision experiments are best suited to sensitively test the few-body dynamics of simple systems. The few-body dynamics, in turn, can be sensitively affected by interference effects. However, an important requirement to observe interference effects in atomic scattering experiments is that the incoming projectile beam must be coherent. The coherence properties of the incoming projectile can be controlled by the geometry of the collimating slit placed before the target. We performed a kinematically complete experiment where a 75 keV proton beam is crossed with a molecular hydrogen beam to study the dissociative capture process. The motivation for this project was …

Survivor Bond Models For Securitizing Longevity Risk, Priscilla Mansah Codjoe

Doctoral Dissertations

"Longevity risk is the risk that a reference population’s mortality rates deviate from what is projected from prior life tables. This is due to discoveries in biological sciences, improved public health measures, and nutrition, which have dramatically increased life expectancy. Longevity risk raises life insurers’ liability, increasing product costs and reserves. Securitization through longevity derivatives is a way of dealing with this risk.

To enhance the pricing of life contingent products, we present an additive type mortality model in the style of the Lee-Carter. This model incorporates policyholder covariates. By using counting processes and martingale machinery, we obtain close form …

Hydroclimate Variability In Central America During The Holocene Inferred From Lacustrine Sediments In Lake Izabal, Eastern Guatemala, Edward Fernando Duarte

Doctoral Dissertations

"Holocene hydroclimate reconstructions have contributed to our understanding of the mechanisms controlling precipitation in Central America. Recent hydroclimate proxy records from the region, however, have revealed considerable spatiotemporal complexity in precipitation variability. This complexity is hypothesized to result from the interaction between multiple oceanic-atmospheric processes that converge in the region. This project analyzed three sediment cores from Lake Izabal, eastern lowland Guatemala, with the goal of understanding changes in precipitation, lake productivity, and lake water chemistry during the Holocene. Our proxy results indicate that precipitation in the region increased from the early to the middle Holocene, when Lake Izabal became …

Social Media Analytics With Applications In Disaster Management And Covid-19 Events, Md Yasin Kabir

Doctoral Dissertations

"Social media such as Twitter offers a tremendous amount of data throughout an event or a disastrous situation. Leveraging social media data during a disaster is beneficial for effective and efficient disaster management. Information extraction, trend identification, and determining public reactions might help in the future disaster or even avert such an event. However, during a disaster situation, a robust system is required that can be deployed faster and process relevant information with satisfactory performance in real-time. This work outlines the research contributions toward developing such an effective system for disaster management, where it is paramount to develop automated machine-enabled …

Secured Information Dissemination And Misbehavior Detection In Vanets, Ayan Roy

Doctoral Dissertations

"In a connected vehicle environment, the vehicles in a region can form a distributed network (Vehicular Ad-hoc Network or VANETs) where they can share traffic-related information such as congestion or no-congestion with other vehicles within its proximity, or with a centralized entity via. the roadside units (RSUs). However, false or fabricated information injected by an attacker (or a malicious vehicle) within the network can disrupt the decision-making process of surrounding vehicles or any traffic-monitoring system. Since in VANETs the size of the distributed network constituting the vehicles can be small, it is not difficult for an attacker to propagate an …

Development Of Flood Prediction Models Using Machine Learning Techniques, Bhanu Kanwar

Doctoral Dissertations

"Flooding and flash flooding events damage infrastructure elements and pose a significant threat to the safety of the people residing in susceptible regions. There are some methods that government authorities rely on to assist in predicting these events in advance to provide warning, but such methodologies have not kept pace with modern machine learning. To leverage these algorithms, new models must be developed to efficiently capture the relationships among the variables that influence these events in a given region. These models can be used by emergency management personnel to develop more robust flood management plans for susceptible areas. The research …

Fully Kinetic Particle-In-Cell Simulations Of Plasma-Surface-Dust Interactions For Lunar Exploration, Jianxun Zhao

Doctoral Dissertations

"The studies involving lunar surface explorations have drawn attentions in recent years. A better understanding of possible potential hazards to astronauts and electronic equipment has become a necessity for future lunar explorations. The lunar surface, lacking an atmosphere and global magnetic field therefore directly exposed to solar radiation and solar wind plasma, is electrically charged by the bombardment of solar wind plasma and emission/collection of photoelectrons. Additionally, lunar dust grains can also get charged and levitated from the surface under the influence of the electric field as well as gravity within the plasma sheath. Since the plasma sheath formed near …

Studies Of Multiphase Distribution And Flow In Bubble/ Slurry Bubble Columns With /Without Internals And Advanced Sustainable Construction Materials Using Sophisticated Measurement Techniques, Omar Farid

Doctoral Dissertations

"Bubble/slurry bubble columns have been widely studied and employed as multiphase flow reactors with and without vertical heat-exchanging tubes. In order to understand more deeply the effect of the dense internals on the hydrodynamics of bubble/slurry bubble column, systematic experiments were performed to visualize and quantify using the radioactive particle tracking (RPT) technique. A new methodology for implementing the radioactive particle tracking (RPT) technique has been developed to investigate the effect of the dense internals on the hydrodynamics of the bubble/slurry column reactor. Monte Carlo N-Particle (MCNP) simulation has been implemented to simulate the system to generate a large number …

Practices Of Instructional Leaders Which Support And Monitor Implementation Of Individualized Education Plans And Influence Teaching In Inclusive Classroom Settings, Pamela D. Williams

Doctoral Dissertations

This qualitative case study was designed to learn more about how the practices of instructional leaders support and monitor the implementation of Individual Education Plans (I.E.P.s) and influence teaching in inclusive classroom settings. It was designed to explore a sample of general educators’ and administrators’ perceptions about the challenges they face to remain in adherence to obligations bound by duty to deliver I.E.P. services as outlined by the Individuals with Disabilities Education Act (IDEA). The selected participants were twelve middle school general educators and administrators from two school districts in northwest Louisiana chosen through purposive sampling. The primary data collection …

A Qualitative Study Identifying Perspectives, Experiences, And Needs Of School Principals And Teachers To Lead A Culture Of Differentiated Teaching And Learning, Natalie Gray Pope

Doctoral Dissertations

Differentiated instruction is defined as providing all students access to the same set of curricula while at the same time providing tasks and instruction tailored to a student’s specific learning style. This expectation has led researchers to study and understand differentiated instruction for embedded applications across all classroom and district experiences, public perceptions, and effective implementation of future trends. However, there is a gap in literature addressed by this study relating to the leadership of differentiated instruction in school settings.

Data for this study were collected from school principals and classroom teachers using both virtual and face-to-face interviews, documented field …

Assessing Gender Bias In Student Evaluations Of Teaching In Collegiate Aviation, Kary M. Randall

Doctoral Dissertations

Student evaluations of teaching (SET) are commonly used to assess teaching effectiveness and influence personnel decisions in higher education. This quantitative study sought to determine if gender and years of teaching experience were related to SET ratings for collegiate aviation faculty. Constructs evaluated related to gender stereotypes and consisted of expressiveness and immediacy as stereotypically female and professionalism and openness as stereotypically male. The overall rating was also analyzed as a fifth construct. Evaluation ratings from 54 participants associated with nine Aviation Accreditation Board International affiliated institutions were analyzed for the 2017 to 2020 academic years. Findings from the two-way …

Science Instructional Leadership Knowledge: A Qualitative Case Study, Mary Ann Chapman

Doctoral Dissertations

This qualitative case study aimed to investigate instructional leaders’ depths of science content knowledge and pedagogical content knowledge and how their depths of that knowledge supports effective instructional leadership. Implementation efforts around the Next Generation Science Standards (NGSS) have highlighted the need for science instructional leaders to have in-depth content and pedagogical knowledge to function as effective instructional leaders in secondary science classrooms across the United States. Semi-structured interviews with 19 teachers and instructional leaders in a public high school in the southern United States informed the study. The findings revealed that teachers expect instructional leaders to have higher levels …

Novice Teachers As Teacher Leaders: A Mixed Methods Study Of Years Of Experience And Teacher Leadership Development, Miranda Owens Allen

Doctoral Dissertations

The aim of this research was to address the gap in the literature on novice teacher leadership development from novice teachers’ perspectives. An explanatory sequential mixed methods design was used to identify the differences that years of experience may or may not have on southern US public school novice teachers’ teacher leadership identity, readiness, and engagement. Distributed leadership theory provided the theoretical lens and Sinha and Hanuscin’s (2017) Teacher Leadership Development Process Model was used as the conceptual framework.

Survey data were collected from 306 full-time pre-k through fifth grade teachers from 71 public elementary schools. One-way ANOVAs measured statistical …

The Effects Of Disorder In Van Der Waals Materials, Jake Riffle

Doctoral Dissertations

Due to their two-dimensional structure and wide range of electronic behaviors, van derWaals materials have garnered a lot of attention for new technological applications. However, much is still unknown about the consequences that impurities and disorder have on the performance of many new van der Waals materials. In my research I use scanning tunneling microscopy(STM) and electronic transport techniques to study the different types of disorder in three common van der Waals materials: tantalum disulfide (TaS2), black phosphorus (BP), and two-dimensional graphene. In TaS2 I show a sample preparation dependence on the surface state of the bulk crystal and emphasize …

Heat Transport By Baroclinic Acoustic Streaming, Jacques Abdul Massih

Doctoral Dissertations

Acoustic streaming refers to time-averaged flows generated by time-periodic sound waves. In classic“Rayleigh streaming”, the mean flow is generated by the interaction of a standing acoustic wave with a solid boundary (e.g., a channel wall). Applications of acoustic streaming include inducing fluid mixing in microfluidic medical devices, improving the efficiency of chemical reactions, and enhancing heat transfer. Recently, Chini et al. [J. Fluid Mech., Vol. 744 (2014)] and Michel & Chini [J. Fluid Mech., Vol. 858 (2019)] demonstrated that strong acoustic streaming flows can be generated in gases subjected to an imposed cross-channel temperature gradient. In contrast with Rayleigh streaming, …

Penalized Regression Splines-Based Tests For Comparing Two Time Series With Unequal Lengths, Mirajul Islam

Doctoral Dissertations

The Spline-based modeling has been an established tool for parametric and nonparametricregression modeling because of its continuous progress on theoretical and computational fronts over the last three decades. This thesis explores the idea of penalized spline modeling and goodness of fit testing in the context of time series testing in the frequency domain approach. The comparison of different time series is an important topic in statistical data analysis and has various applications in scientific research. One approach to identifying similarities or dissimilarities between two stationary processes is to compare the spectral densities of both time series. This thesis examines whether …

Efficient Data-Driven Robust Policies For Reinforcement Learning, Bahram Behzadian

Doctoral Dissertations

Applying the reinforcement learning methodology to domains that involve risky decisions like medicine or robotics requires high confidence in the performance of a policy before its deployment. Markov Decision Processes (MDPs) have served as a well-established model in reinforcement learning (RL). An MDP model assumes that the exact transitional probabilities and rewards are available. However, in most cases, these parameters are unknown and are typically estimated from data, which are inherently prone to errors. Consequently, due to such statistical errors, the resulting computed policy's actual performance is often different from the designer's expectation. In this context, practitioners can either be …

Sociocultural Dimensions Of Environmental Stewardship In New Hampshire: Implications For Adult Environmental Education, Ian Patrick Hanley

Doctoral Dissertations

The overarching aim of this dissertation is to expand evidence and theory of adult identity processes in the context of environmental stewardship, as well as to provide knowledge and recommendations to environmental stewardship and environmental education professionals. The intent is to better understand variation in how adult environmental stewards report on and value their own engagement with both sociocultural and natural systems. This line of inquiry stems from the fundamental claim that environmental stewardship activity is not singularly based on environmental content knowledge but is also related to forms of cultural and social engagement. By recognizing these dual aspects of …

Water Droplet Machining And Droplet Impact Mechanics, Benjamin Mitchell

Doctoral Dissertations

Water Droplet Machining (WDM) is a new manufacturing process, which uses a series of high-velocity, pure-water droplets to impact and erode metal workpieces, for the purpose of through-cutting, milling and surface profiling. The process is conducted within a vacuum environment to suppress aerodynamic drag and atomization of the waterjet and droplet stream. This preserves droplet momentum and allows for a more efficient transfer of energy between the water and workpiece, than in standard atmospheric pressure. As a new manufacturing technique, parameter-specific details and characteristics of this process are absent from the scientific literature. Furthermore, the erosion mechanisms involved in droplet-solid …

Query-Specific Subtopic Clustering In Response To Broad Queries, Sumanta Kashyapi

Doctoral Dissertations

Information Retrieval (IR) refers to obtaining valuable and relevant information from various sources in response to a specific information need. For the textual domain, the most common form of information sources is a collection of textual documents or text corpus. Depending on the scope of the information need, also referred to as the query, the relevant information can span a wide range of topical themes. Hence, the relevant information may often be scattered through multiple documents in the corpus, and each satisfies the information need to varying degrees. Traditional IR systems present the relevant set of documents in the form …

The Efficacy Of Response To Intervention On Academic Outcomes At The Secondary School Level In A New England School District, Kimberly Mcglinchey

Doctoral Dissertations

Educational policies and practices have had a long-standing emphasis of conducting incoming literacy screenings to determine who is at risk for school failure. Response to intervention (RTI) is an intervention program designed to deliver educational resources to students who fall below what is deemed an acceptable level of proficiency as viewed through the early screening process. The goal of the program is to provide early mitigation in order to catch students up to their peers, and to limit misidentification into special education. Studies have evaluated the success of the program in grades K-3 and shown mixed success. However, there was …

The Active Tail In The Mms Era: An Ion Perspective, Anthony Jason Rogers

Doctoral Dissertations

The Earth's magnetic field has a complex and dynamic relationship with the greater solar system. The solar wind and interplanetary magnetic field extend the influence of the Sun's atmosphere to the orbit of Earth and well beyond, carrying charged particles in a constant stream of varying density and velocity. These solar influences carry energy which interacts with every object they encounter, including the Earth and its magnetic field.

The primary mechanism for the energetic interaction and exchange of energy between the Earth's magnetic field and the solar wind is called Magnetic Reconnection, a process by which two opposing magnetic fields …

Effect Of Endogenous And Exogenous Agents In Platelet Adhesion, Sowjanya Dokku

Doctoral Dissertations

Platelet adhesion is regulated by both activators, such as adenosine diphosphate, and inhibitors, such as nitric oxide (NO). Both agents are released on platelet activation, so that platelets initiate both positive and negative feedback systems. In vivo platelet adhesion models generally consider the effects of platelet activators and inhibitors separately. The goal of this study was to create an environment in which interplay between positive and negative feedback can be observed together and in which the roles of endogenous and exogenous platelet activators are distinguishable. The results are expected to be applicable to the design of stents, which are susceptible …

Epileptogenic Focus Localization By Novel Analysis Of Lntracranial Eeg In The Frequency Domain, Omar Ali Alamoudi

Doctoral Dissertations

The gold standard for localization of the epileptogenic zone (EZ) continues to be the visual inspection of electrographic changes during seizure onset by experienced EEG readers. Development of an epileptogenic focus localization tool that can accurately delineate the EZ from the analysis of interictal (seizure-free) period is still an open question of great significance for improved diagnosis (e.g., presurgical evaluation) and treatment (e.g., surgical) outcome. We developed an EZ localization algorithm (LA) based on novel analysis of the power in a narrow frequency band of the recorded signals from the brain, that is, using a simple univariate periodogram-type power measure, …

Parallel Computing Framework And Gpu Performance Modeling, Wenjing Xu

Doctoral Dissertations

During the past decades, High-Performance Computing (HPC) has been widely used in various industries. In particular, the exponential growth of GPU (graphics processing unit) is a key technology that has helped promoting the development of artificial intelligence in real-world use cases. When we use GPU to accelerate parallel applications, its programmability, resource management, and scheduling are non-trivial jobs to obtain optimized performance. Therefore, how to effectively exploit GPU resources and improve program performance has been a hot research topic recently.

Benchmark does not always provide a good picture of the performance and details of the parallel applications. The various kinds …