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549 Matching Results

Start Over Partner UNT Libraries Year 2021 Language English

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The Effect of Online Consumer Reviews and Brand Equity on the Consumer Decision Making Process

This research aims to investigate the (1) review effects on consumer decision making process, (2) effects of negative reviews on brand equity, and (3) consumers' likely response to a brand's request for reviews. The objective of the first essay is to investigate the nature of the relationship between skepticism and consumer decision making in an online behavior context. Its second objective is to know whether people's belief on their abilities or their hedonic principle moderates the relationship between a person's skepticism toward online reviews and their reliance on online reviews. The objective of the second essay is to explore whether negative online reviews that focus on service quality specific dimensions have a different effect on a service organization's perceived brand equity. Its second objective is to analyze the role of emotional contagion in the relationship between negative reviews related to various service quality dimensions and its effect on perceived brand equity. The main objective of the third essay is to know whether consumers are more likely to write an online review for a brand when the request comes from a higher equity brand. This essay also investigates how message trust and persuasion knowledge influence the relationship between a brand's request …

Date: December 2021

Creator: Ahmad, Fayez

Object Type: Thesis or Dissertation

System: The UNT Digital Library

Understanding the RCS Way: A Study of Organizational Culture

The quality of workplace morale can positively and negatively affect employee engagement. Engaged employees are more likely to participate in active communication with one another. They are also more likely to adopt the organizational goals and work towards creating a productive work environment. Communication and engagement build trust. Established trust between employees and executive leadership is a delicate relationship to maintain, though it is necessary when contending with periods of stress. The organization profiled below experienced the stressor of needing to grow without alienating those afraid of change or used to operating in one predictable direction. There was a desire to generate engagement, build trust and make room for employee-directed change. This desire left the organization open to exploring its culture and its impact on employee engagement.

Date: December 2021

Creator: Terry, Vanessa S.

Object Type: Thesis or Dissertation

System: The UNT Digital Library

The Effects of a Contingent S-Delta

This thesis attempted a cross-species replication of Bland, et. al., 2018. Human participants went through a computerized, automated shaping procedure that trained them to click on and discriminate between a blue square (SD) and red square (S-delta) on a VR 12 schedule of reinforcement. Three conditions were then presented to the participants consisting of a baseline, punishment, and control condition. In the punishment and control conditions, the SD was replaced by the S-delta or a novel stimulus respectively for 1-second on a VR 5 schedule. With each click, the reaction time and specific object clicked on were recorded. While the present study partially replicated the effect seen in earlier research, our results suggest that, depending on the lens of analysis used, either a punishment or an extinction effect may be causing the results seen.

Date: December 2021

Creator: Ochoa, Jules

Object Type: Thesis or Dissertation

System: The UNT Digital Library

Corrosion Mechanism and Prevention of Wire Bonded Device in Microelectronic Manufacturing and Spectroscopic Investigation of Copper Etch Chemical Equilibria for High Density Interconnect Application

In the first part of this dissertation work, Al bond pad corrosion behavior was investigated in the presence of common industrial contaminants such as chloride (Cl-) and fluoride (F-). Al corrosion while in direct contact with Cu displayed rapid hydrogen (H2) gas evolution and dendrite propagation. In contrast, Al without bimetallic contact showed only minor surface roughening. This observed difference in the corrosion mechanism between Cl- and F- is attributed to the solubility of the corrosion products (AlCl3 vs. AlF3) formed on the Al surface. Our subsequent work explored corrosion prevention inhibition of wire-bonded devices (WBD) in the Cl- environment. Our research shows that the Al bond pad was protected against corrosion by chemically modifying the surface of the Cu wires, thereby preventing the H2 evolution. The inhibitor was observed to be highly selective, thermally stable, hydrophobic, and cost-effective, making it viable for industrial application of this coating for Al bond pad corrosion prevention. In the second part of the dissertation work, we utilized a novel approach of using ultraviolet-visible spectroscopy (UV-Vis) as a chemical-sensitive monitoring tool of the chemical environment in Cu etch bath. The UV-Vis technique illuminates the roles of H+, Cl-, Cu+, and Cu2+ to the etch …

Date: December 2021

Creator: Ashok Kumar, Goutham Issac

Object Type: Thesis or Dissertation

System: The UNT Digital Library

(open access)

Instrumental Development and Implementation of Portable Membrane Inlet Mass Spectrometry for Homeland Security and Environmental Applications

A rapidly growing topic of great interest is the adaptation of benchtop analytical instrumentation for use in outdoor harsh environments. Some of the areas that stand to benefit from field instrumentation development include government agencies involved with the preservation of the environment and institutions responsible for the safety of the general public. Detection systems are at the forefront of the miniaturization movement as the interest in analyte identification and quantitation appears to only be accessible through the use of analytical instrumentation. Mass spectrometry is a distinguished analytical technique known for its ability to detect the mass-to-charge (m/z) ratios of gas-phase ions of interest. Although these systems have been routinely limited to research lab-based analysis, there has been considerable development of miniaturized and portable mass spectrometry systems. Membrane Inlet Mass Spectrometry (MIMS) is becoming a common method of sample introduction that is subject to significant development. MIMS allows for minimal sample preparation, continuous sampling, and excludes complicated analyte introduction techniques. Sampling is accomplished using a semipermeable membrane that allows selective analyte passage into the vacuum of the mass spectrometer. MIMS is becoming the preeminent choice of homeland security and environmental monitoring applications with increasing opportunities for the future development of specialized …

Date: December 2021

Creator: Anguiano Virgen, Camila

Object Type: Thesis or Dissertation

System: The UNT Digital Library

Forging Pathways: A Multi-Case Study of Individuals with Intellectual Disability Pursuing Postsecondary Education at the Community College

This multi-case study sought to better understand how students with intellectual disability (ID) are forging pathways to higher education via the community college. Five individuals with ID who accessed higher education via the community college and their parents/guardians were interviewed. Each case provided insight into personal pathways with results given in case descriptions and individual case themes. Cross-case analysis revealed four themes positively impacting the college-going pathway for students with ID: value-driven grit, pathway knowledge, community support, and accessibility. Based on findings from this study, families appear to be the primary systems forging pathways to the community college for individuals with ID. Local education agencies and community colleges can assist these families by engaging in interagency collaboration, evaluating their systems, and aligning practices to the goal of students with ID accessing and engaging in higher education.

Date: December 2021

Creator: Jackson, Amanda O.

Object Type: Thesis or Dissertation

System: The UNT Digital Library

Advanced Cathodes for High Energy Density Lithium Sulfur Battery

A systematic development of 2D alloy catalyst with synergistic performance of high lithium polysulfide (LiPS) binding energy and efficient Li+ ion/electron conduction is presented. The first section of work found that Li+ ions can flow through the percolated ion transport pathway in polycrystalline MoS2, while Na+ and K+ ions can easily flow through the percolated 1D ion channel near the grain boundaries. An unusually high ionic conductivity of extrinsic Li+, Na+, and K+ ions in 2D MoS2 film exceeding 1 S/cm was measured that is more than two orders of magnitude higher than those of conventional solid ionic materials, including 2D ionic materials. The second section of this dissertation focus on catalyzing the transformation of LiPSs to prevent the shuttle effect during the battery cycling by synthesizing 2H (semiconducting) – 1T (metallic) mixed phase 2D Mo0.5W0.5S2 alloy on CNF paper, using two step sputtering and sulfurization method. The lithium sulfur (Li-S) battery cell assembled with the 2D Mo0.5W0.5S2/CNF/S cathode shows a high specific capacity of 1228 mAh g-1 at 0.1C and much higher cyclic stability over 4 times as compared to the pristine cathodes. The high LiPSs binding energy of catalyst efficiently prevents the shuttling effect and corrosion of Li …

Date: December 2021

Creator: Bhoyate, Sanket

Object Type: Thesis or Dissertation

System: The UNT Digital Library

Reliability Characterization and Performance Analysis of Solid State Drives in Data Centers

NAND flash-based solid state drives (SSDs) have been widely adopted in data centers and high performance computing (HPC) systems due to their better performance compared with hard disk drives. However, little is known about the reliability characteristics of SSDs in production systems. Existing works that study the statistical distributions of SSD failures in the field lack insights into distinct characteristics of SSDs. In this dissertation, I explore the SSD-specific SMART (Self-Monitoring, Analysis, and Reporting Technology) attributes and conduct in-depth analysis of SSD reliability in a production environment with a focus on the unique error types and health dynamics. QLC SSD delivers better performance in a cost-effective way. I study QLC SSDs in terms of their architecture and performance. In addition, I apply thermal stress tests to QLC SSDs and quantify their performance degradation processes. Various types of big data and machine learning workloads have been executed on SSDs under varying temperatures. The SSD throughput and application performance are analyzed and characterized.

Date: December 2021

Creator: Liang, Shuwen (Computer science and engineering researcher)

Object Type: Thesis or Dissertation

System: The UNT Digital Library

(open access)

Unraveling the Effect of Atomic Configurations and Structural Statistics on Mechanical Behavior of Multicomponent and Amorphous Alloys

Multicomponent high-entropy and amorphous alloys represent relatively new classes of structural materials with complex atomic configurations and exceptional mechanical properties. However, there are several knowledge gaps in the relationships between their atomic structure and mechanical properties. Understanding these critical relationships will enable novel alloy design and tailoring of their mechanical properties for desired engineering applications. In this dissertation, first-principles calculations and molecular dynamics simulations are applied to investigate the local atomic configurations and ordering in high-entropy and amorphous alloys. Our findings suggest that fluctuations in local atomic configurations for high- entropy alloys result in significant changes in stacking fault energy, twin energy, dislocation behavior, dislocation-twin interactions, and critical shear stress. For amorphous alloys or metallic glasses, the short-range order (SRO) and medium-range order (MRO) were found to play decisive roles in determination of their mechanical properties. Structural relaxation was found to lead to shear localization, which was attributed to free volume change and evolution of SRO and MRO to more brittle nature. In contrast, rejuvenated metallic glasses had relatively large and uniform free volume distribution giving rise to homogeneous flow and increased plasticity.

Date: December 2021

Creator: Yang, Yu Chia

Object Type: Thesis or Dissertation

System: The UNT Digital Library

(open access)

The Examination of Black and Latino/a/x Students' and Responsive STEM Teachers' Perceptions of Teacher Cultural Consciousness and Culturally Responsive Instructional Practices

School cultures, curriculum, and instruction are too often created through a monocultural lens, which excludes Black and Latino/a/x students both socially and academically, and perpetuates the false notion that these students are inherently less capable of achieving academic success when compared to their White counterparts. This is visible across all content areas, but especially in secondary science, technology, engineering, and mathematics (STEM) classes, which means that our Black and Latino/a/x students are continually denied preparation for the critical, high demand careers in the STEM field. Just as critical, with the dominance of White teachers in the classroom, out Black and Latino/a/x students often do not have access to teachers who share their lived experiences or who understand the nuances of their home cultures. However, teachers and school instructional leaders can change course by focusing their efforts to develop a rich cultural consciousness, and by focusing on the utilization of culturally responsive pedagogy (CRP) and related instructional strategies with great intentionality in the classroom. This mixed method, single site, exploratory case study was conducted to examine Black and Latino/a/x students' perceptions of their culturally responsive STEM teachers' cultural consciousness, and culturally responsive STEM teachers' perceptions of culturally responsive practices and their …

Date: December 2021

Creator: Norris, Margaret Louise

Object Type: Thesis or Dissertation

System: The UNT Digital Library

(open access)

Domain Specific Cognitive Effects of Sickle Cell Disease in Children

Multiple contributors to neurocognitive impairment in individuals with sickle cell disease have been identified. Research indicates that a history of cerebrovascular accidents, such as silent infarcts and strokes are associated with greater cognitive decline among children with sickle cell disease. Additionally, disease effects such as hemoglobin and hematocrit levels significantly effect cognitive performance among this population and should be taken into consideration when examining neurocognitive impairment. Further, previous studies show a significant relationship between child behavior problems, family functioning, and cognitive performance in children with sickle cell, marking those as important targets for intervention among this population. While cognitive decline with increased age is not typically examined in healthy child populations, some research indicates the presence of age effects in those with SCD. A majority of the literature addresses cognitive impairment from a broad perspective, while a limited number of studies have begun to address effects among specific cognitive domains. Using archival data from the National Institutes of Health's Cooperative Study of Sickle Cell Disease, results revealed that disease severity was negatively correlated with some aspects of cognitive functioning, including visual-spatial domains. Additionally, some measures of cognitive performance were inversely correlated with age. Consistent with hypothesized outcomes, family functioning was …

Date: December 2021

Creator: Carroll, Bridgette

Object Type: Thesis or Dissertation

System: The UNT Digital Library

(open access)

Air Corridors: Concept, Design, Simulation, and Rules of Engagement

Air corridors are an integral part of the advanced air mobility infrastructure. They are the virtual highways in the sky for transportation of people and cargo in the controlled airspace at an altitude of around 1000 ft. to 2000 ft. above the ground level. This paper presents fundamental insights into the design of air corridors with high operational efficiency as well as zero collisions. It begins with the definitions of air cube, skylane or track, intersection, vertiport, gate, and air corridor. Then, a multi-layered air corridor model is proposed. Traffic at intersections is analyzed in detail with examples of vehicles turning in different directions. The concept of capacity of an air corridor is introduced along with the nature of distribution of locations of vehicles in the air corridor and collision probability inside the corridor are discussed. Finally, the results of simulations of traffic flows are presented.

Date: December 2021

Creator: Muna, Sabrina Islam

Object Type: Thesis or Dissertation

System: The UNT Digital Library

A Proposal for a Training Program to Support Culturally Responsive Professional-Family Interactions

Behavior analysts often work with families from diverse cultural backgrounds. Ideally, behavior analysts and families interact in ways that are responsive to the family's culture and valued outcomes. The data indicate that most behavior analysts, however, come from one dominant cultural group. This is a proposal for training program and evaluation method to support culturally responsive professional-family interactions. This proposed study is designed to be conducted via Zoom-- a cloud-based video conferencing service. A pre-post treatment design is proposed to assess the effects of the training. Hypothetical data were generated to consider the range of effects such a program might have on trainee responses to written/live scenarios. Responses in the observation protocol included written descriptions, empathetic statements, perspective taking statements, and non-verbal behaviors. Overall, the program was designed using evidence-based procedures and is likely to support behavior analysts in training and in practice to improve their interactions with families and become more culturally responsive to groups of people that are from the non-dominant culture.

Date: December 2021

Creator: Anegbeh, Cynthia Momoh

Object Type: Thesis or Dissertation

System: The UNT Digital Library

A New Class of Stochastic Volatility Models for Pricing Options Based on Observables as Volatility Proxies

One basic assumption of the celebrated Black-Scholes-Merton PDE model for pricing derivatives is that the volatility is a constant. However, the implied volatility plot based on real data is not constant, but curved exhibiting patterns of volatility skews or smiles. Since the volatility is not observable, various stochastic volatility models have been proposed to overcome the problem of non-constant volatility. Although these methods are fairly successful in modeling volatilities, they still rely on the implied volatility approach for model implementation. To avoid such circular reasoning, we propose a new class of stochastic volatility models based on directly observable volatility proxies and derive the corresponding option pricing formulas. In addition, we propose a new GARCH (1,1) model, and show that this discrete-time stochastic volatility process converges weakly to Heston's continuous-time stochastic volatility model. Some Monte Carlo simulations and real data analysis are also conducted to demonstrate the performance of our methods.

Date: December 2021

Creator: Zhou, Jie

Object Type: Thesis or Dissertation

System: The UNT Digital Library

Optimal Pair-Trading Decision Rules for a Class of Non-Linear Boundary Crossings by Ornstein-Uhlenbeck Processes

The most useful feature used in finance of the Ornstein-Uhlenbeck (OU) stochastic process is its mean-reverting property: the OU process tends to drift towards its long- term mean (its equilibrium state) over time. This important feature makes the OU process arguably the most popular statistical model for developing best pair-trading strategies. However, optimal strategies depend crucially on the first passage time (FPT) of the OU process to a suitably chosen boundary and its probability density is not analytically available in general. Even for crossing a simple constant boundary, the FPT of the OU process would lead to crossing a square root boundary by a Brownian motion process whose FPT density involves the complicated parabolic cylinder function. To overcome the limitations of the existing methods, we propose a novel class of non-linear boundaries for obtaining optimal decision thresholds. We prove the existence and uniqueness of the maximizer of our decision rules. We also derive simple formulas for some FPT moments without analytical expressions of its density functions. We conduct some Monte Carlo simulations and analyze several pairs of stocks including Coca-Cola and Pepsi, Target and Walmart, Chevron and Exxon Mobil. The results demonstrate that our method outperforms the existing procedures.

Date: December 2021

Creator: Tamakloe, Emmanuel Edem Kwaku

Object Type: Thesis or Dissertation

System: The UNT Digital Library

Behavioral and Neural Correlates of Speech Perception Outcomes in Adults with Cochlear Implants

Postlingually deafened cochlear implant (CI) adults have large variability in speech perception abilities. While CIs are one of the most successful neural prosthetic devices, they are not able to adequately provide fine structure cues which results in a degraded signal for the listener to interpret. While behavioral measures remain the gold standard for determining speech perception abilities, an objective measure is needed for patients who are unable to provide reliable behavioral responses. Behavioral, cognitive, and neural measures were collected in this study to identify potential neural biomarkers that correlate with speech perception performance. Behavioral experiments evaluated participants' abilities to identify, discriminate, and recognize words as well as sentences in quiet and in noise. Cognitive measures were assessed to determine the roles of attention, impulse control, memory, and cognitive flexibility on speech recognition. Auditory event-related potentials (ERP) were obtained with a double oddball paradigm to produce the mismatch negativity (MMN) response, which has been shown to have associations with phonetic categorical perception at the group level. The results indicated that executive function is highly predictive of speech performance and that the MMN is associated with categorical perception at the individual level. These findings are clinically relevant to determining appropriate follow-up care …

Date: December 2021

Creator: Manning, Jacy

Object Type: Thesis or Dissertation

System: The UNT Digital Library

Online Testing of Context-Aware Android Applications

This dissertation presents novel approaches to test context aware applications that suffer from a cost prohibitive number of context and GUI events and event combinations. The contributions of this work to test context aware applications under test include: (1) a real-world context events dataset from 82 Android users over a 30-day period, (2) applications of Markov models, Closed Sequential Pattern Mining (CloSPAN), Deep Neural Networks- Long Short Term Memory (LSTM) and Gated Recurrent Units (GRU), and Conditional Random Fields (CRF) applied to predict context patterns, (3) data driven test case generation techniques that insert events at the beginning of each test case in a round-robin manner, iterate through multiple context events at the beginning of each test case in a round-robin manner, and interleave real-world context event sequences and GUI events, and (4) systematically interleaving context with a combinatorial-based approach. The results of our empirical studies indicate (1) CRF outperforms other models thereby predicting context events with F1 score of about 60% for our dataset, (2) the ISFreqOne that iterates over context events at the beginning of each test case in a round-robin manner as well as interleaves real-world context event sequences and GUI events at an interval one achieves …

Date: December 2021

Creator: Piparia, Shraddha

Object Type: Thesis or Dissertation

System: The UNT Digital Library

Integrating Multiple Deep Learning Models to Classify Disaster Scene Videos

Recently, disaster scene description and indexing challenges attract the attention of researchers. In this dissertation, we solve a disaster-related multi-labeling task using a newly developed Low Altitude Disaster Imagery dataset. In the first task, we realize video content by selecting a set of summary key frames to represent the video sequence. Through inter-frame differences, the key frames are generated. The key frame extraction of disaster-related video clips is a powerful tool that can efficiently convert video data into image-level data, reduce the requirements for the extraction environment and improve the applicable environment. In the second, we propose a novel application of using deep learning methods on low altitude disaster video feature recognition. Supervised learning-based deep-learning approaches are effective in disaster-related features recognition via foreground object detection and background classification. Performed dataset validation, our model generalized well and improved performance by optimizing the YOLOv3 model and combining it with Resnet50. The comprehensive models showed more efficient and effective than those in prior published works. In the third task, we optimize the whole scene labeling classification by pruning the lightweight model MobileNetV3, which shows superior generalizability and can disaster features recognition from a disaster-related dataset be accomplished efficiently to assist disaster recovery.

Date: December 2021

Creator: Li, Yuan

Object Type: Thesis or Dissertation

System: The UNT Digital Library

Quantifying the Effects of Single Nucleotide Changes in the TATA Box of the Cauliflower Mosaic Virus 35S Promoter on Gene Expression in Arabidopsis thaliana

Synthetic biology is a rapidly growing field that aims to treat cellular biological networks in an analogous way to electrical circuits. However, the field of plant synthetic biology has not grown at the same pace as bacterial and yeast synthetic biology, leaving a dearth of characterized tools for the community. Due to the need for tools for the synthetic plant biologist, I have endeavored to create a library of well-characterized TATA box variants in the cauliflower mosaic virus (CaMV) 35S promoter using the standardized assembly method Golden Braid 2.0. I introduced single nucleotide changes in the TATA box of the CaMV 35S promoter, a genetic part widely used in plant gene expression studies and agricultural biotechnology. Using a dual-luciferase reporter system, I quantified the transcriptional strength of the altered TATA box sequences and compared to the wild-type sequence, both in transient protoplast assays and stable transgenic Arabidopsis thaliana plants. The library of TATA-box modified CaMV 35S promoters with varying transcriptional strengths created here can provide the plant synthetic biology community with a series of modular Golden Braid-adapted genetic parts that can be used dependably and reproducibly by researchers to fine-tune gene expression levels in complex, yet predictable, synthetic genetic circuits.

Date: December 2021

Creator: Amack, Stephanie C.

Object Type: Thesis or Dissertation

System: The UNT Digital Library

Body Doubles: Materiality and Gender Non-Binarism in Victorian Supernatural Fiction

This dissertation is a study of supernatural doubles in Victorian literature. It argues that these doubles expand our understanding of gender variance in the Victorian period. The texts in this dissertation privilege gender non-binarism through their depictions of materiality, gender embodiment, and temporality.

Date: December 2021

Creator: Schneider, Katherine

Object Type: Thesis or Dissertation

System: The UNT Digital Library

Anxiously Yours, (fe)mail: A Narrative Exploration of Anxiety, Empathy and Hope in Art Museum Education

This research explores the relationship between narrative, empathy and anxiety in art museum education. The study begins from my personal experience with anxiety and is methodologically rooted in narrative inquiry and friendship as method. In this study, I propose a creative method of narrative postcard writing called (fe)mail – rooted in a feminist ethic of care that seeks to understand and empathize with the experience of others through correspondence. This research asks relevant questions about the future of art museum programming for mental illness and the act of writing (fe)mail as a reflective practice for academics and educators in the field of social science. In my narrative analysis of the program and the data, I also problematizes my role as researcher, educator and friend throughout the study by considering my own biases, expectations and personal educator agenda. The study is divided into two parts. The first comprises correspondence and analysis of (fe)mail between myself and my best friend/co-participant, Atleigh. In Part I, I conduct a narrative analysis of the (fe)mail data produced between us in order to answer the following questions: What qualities of (fe)mail will appear in the exchange? Can (fe)mail be used as a tool for self-care during …

Date: December 2021

Creator: Galuban, Beatriz Asfora

Object Type: Thesis or Dissertation

System: The UNT Digital Library