Digital Commons Network^™

Statistics-Based Anomaly Detection And Correction Method For Amazon Customer Reviews, Ishani Chatterjee

Dissertations

People nowadays use the Internet to project their assessments, impressions, ideas, and observations about various subjects or products on numerous social networking sites. These sites serve as a great source of gathering information for data analytics, sentiment analysis, natural language processing, etc. The most critical challenge is interpreting this data and capturing the sentiment behind these expressions. Sentiment analysis is analyzing, processing, concluding, and inferencing subjective texts with the views. Companies use sentiment analysis to understand public opinions, perform market research, analyze brand reputation, recognize customer experiences, and study social media influence. According to the different needs for aspect granularity, …

Machine Learning Techniques For Network Analysis, Irfan Lateef

Dissertations

The network's size and the traffic on it are both increasing exponentially, making it difficult to look at its behavior holistically and address challenges by looking at link level behavior. It is possible that there are casual relationships between links of a network that are not directly connected and which may not be obvious to observe. The goal of this dissertation is to study and characterize the behavior of the entire network by using eigensubspace based techniques and apply them to network traffic engineering applications.

A new method that uses the joint time-frequency interpretation of eigensubspace representation for network statistics …

Coherent Control Of Dispersive Waves, Jimmie Adriazola

Dissertations

This dissertation addresses some of the various issues which can arise when posing and solving optimization problems constrained by dispersive physics. Considered here are four technologically relevant experiments, each having their own unique challenges and physical settings including ultra-cold quantum fluids trapped by an external field, paraxial light propagation through a gradient index of refraction, light propagation in periodic photonic crystals, and surface gravity water waves over shallow and variable seabeds. In each of these settings, the physics can be modeled by dispersive wave equations, and the technological objective is to design the external trapping fields or propagation media such …

Private And Federated Deep Learning: System, Theory, And Applications For Social Good, Han Hu

Dissertations

During the past decade, drug abuse continues to accelerate towards becoming the most severe public health problem in the United States. The ability to detect drug­abuse risk behavior at a population scale, such as among the population of Twitter users, can help to monitor the trend of drug­abuse incidents. However, traditional methods do not effectively detect drug­abuse risk behavior in tweets, mainly due to the sparsity of such tweets and the noisy nature of tweets. In the first part of this dissertation work, the task of classifying tweets as containing drug­abuse risk behavior or not, is studied. Millions of public …

Improving Programming Learners’ Experience Through Interactive Computer Tutor Based Moocs, Ruiqi Shen

Dissertations

With the large demand for technology workers all around the world, more people are learning programming. Studies show that human tutoring is the most effective way to learn for novice programmers. However, problems such as the inaccessibility to physical classes, prohibitive costs, and the lack of educators may limit students' opportunities to learn from these resources. Additionally, because programming is a skill requiring continuous practice and immediate feedback, simply listening to lectures may not be sufficient to learn effectively. This increases the inconvenience of learners who use online learning tools such as Massive Open Online Courses (MOOCs).

In recent years, …

Iii-Nitride Nanostructures: Photonics And Memory Device Applications, Barsha Jain

Dissertations

III-nitride materials are extensively studied for various applications. Particularly, III-nitride-based light-emitting diodes (LEDs) have become the major component of the current solid-state lighting (SSL) technology. Current III-nitride-based phosphor-free white color LEDs (White LEDs) require an electron blocking layer (EBL) between the device active region and p-GaN to control the electron overflow from the active region, which has been identified as one of the primary reasons to adversely affect the hole injection process. In this dissertation, the effect of electronically coupled quantum well (QW) is investigated to reduce electron overflow in the InGaN/GaN dot-in-a-wire phosphor-free white LEDs and to improve the …

A Vacuum-Driven Distillation Technology Of Aqueous Solutions And Mixtures, Guo Guangyu

Dissertations

Distillation of aqueous solutions and aqueous mixtures has vast industrial applications, including desalination, wastewater treatment, and fruit juice concentration. Currently, two major distillation technologies are adopted in the industry, membrane separation and thermal distillation. However, both of them face certain inevitable drawbacks. Membrane separation has disadvantages as relying on high-grade energy, requiring membrane, fouling problem, narrow treatment range, limited scalability, and vibrating and noisy operating conditions. Traditional thermal distillation technologies can avoid above concerns but has other shortcomings, such as relatively low energy efficiency and yield rate, complicated and bulky system structure, and scaling problem.

This project proposes an innovative …

On Resource-Efficiency And Performance Optimization In Big Data Computing And Networking Using Machine Learning, Wuji Liu

Dissertations

Due to the rapid transition from traditional experiment-based approaches to large-scale, computational intensive simulations, next-generation scientific applications typically involve complex numerical modeling and extreme-scale simulations. Such model-based simulations oftentimes generate colossal amounts of data, which must be transferred over high-performance network (HPN) infrastructures to remote sites and analyzed against experimental or observation data on high-performance computing (HPC) facility. Optimizing the performance of both data transfer in HPN and simulation-based model development on HPC is critical to enabling and accelerating knowledge discovery and scientific innovation. However, such processes generally involve an enormous set of attributes including domain-specific model parameters, network transport …

Experimental And Computational Studies Of Functionalized Carbon Nanotubes For Use In Energy Storage Devices And Membranes, Emine S. Karaman

Dissertations

Electrolytes with good interfacial stability are a crucial component of any electrochemical device. The development of novel gel polymer electrolytes (GEs) with good interface stability and better manufacturability is important for the development of the next generation electrochemical devices. Gel electrolytes are hybrid electrolyte materials, combining benefits of both liquid and solid systems. Compared with liquid and solid electrolytes, GEs open new design opportunities and do not require rigorous encapsulation methods. In this dissertation, studies on functionalized carbon nanotubes (fCNTs) and graphene oxide (GO) doped polyvinyl alcohol (PVA) based gel electrolytes (GEs) are reported. The ionic conductivity and mechanical strength …

Parameter Estimation And Inference Of Spatial Autoregressive Model By Stochastic Gradient Descent, Gan Luan

Dissertations

Stochastic gradient descent (SGD) is a popular iterative method for model parameter estimation in large-scale data and online learning settings since it goes through the data in only one pass. While SGD has been well studied for independent data, its application to spatially-correlated data largely remains unexplored. This dissertation develops SGD-based parameter estimation and statistical inference algorithms for the spatial autoregressive (SAR) model, a common model for spatial lattice data.

This research contains three parts. (I) The first part concerns SGD estimation and inference for the SAR mean regression model. A new SGD algorithm based on maximum likelihood estimator (MLE) …

Scalable Scientific Data Management On High-Performance Computing Systems, Zhenbo Qiao

Dissertations

As high-performance computing (HPC) is being scaled up to exascale to accommodate new modeling and simulation needs, I/O has continued to be a major bottleneck in the end-to-end scientific processes. To bridge the widening gap between compute and I/O, and enable data to be more efficiently stored and analyzed, simulation outputs need to be refactored, reduced, and appropriately mapped to storage tiers. Also, a major question that the community is striving to answer is how to co-design data storage and complex physics-rich analytics in a way that the time to knowledge can be minimized in post-processing. As HPC storage systems …

Dependent Censoring In Survival Analysis, Zhongcheng Lin

Dissertations

This dissertation mainly consists of two parts. In the first part, some properties of bivariate Archimedean Copulas formed by two time-to-event random variables are discussed under the setting of left censoring, where these two variables are subject to one left-censored independent variable respectively. Some distributional results for their joint cdf under different censoring patterns are presented. Those results are expected to be useful in both model fitting and checking procedures for Archimedean copula models with bivariate left-censored data. As an application of the theoretical results that are obtained, a moment estimator of the dependence parameter in Archimedean copula models is …

Machine Learning And Computer Vision In Solar Physics, Haodi Jiang

Dissertations

In the recent decades, the difficult task of understanding and predicting violent solar eruptions and their terrestrial impacts has become a strategic national priority, as it affects the life of human beings, including communication, transportation, the power grid, national defense, space travel, and more. This dissertation explores new machine learning and computer vision techniques to tackle this difficult task. Specifically, the dissertation addresses four interrelated problems in solar physics: magnetic flux tracking, fibril tracing, Stokes inversion and vector magnetogram generation.

First, the dissertation presents a new deep learning method, named SolarUnet, to identify and track solar magnetic flux elements in …

Design And Learning-Based Decoding Of Low-Density-Parity-Check Codes For Multiterminal Communication, Salman Habib

Dissertations

The field of information theory was initiated by Claude Shannon in 1948. According to his most notable work, data can be transmitted reliably over a noisy communication channel with high probability, as long as a suitable coding scheme is employed to protect the data from channel noise. Since then, coding theorists have made numerous attempts to design low-complexity error correcting schemes which achieve the Shannon limit.

In the 1960s, Robert Gallager introduced sparse graph-based low-density-parity-check (LDPC) codes which are practically suitable for various coding applications, mainly due to their low encoding and decoding complexity compared to classical codes (e.g., Reed-Muller …

Bodipy Based Photodynamic Therapy And Potassium Probes, Xiangshan Liu

Dissertations

Boron dipyrromethene (BODIPY) has become more and more popular in photophysical and biological applications. BODIPY based fluorescence compounds have numerous advantage properties including low toxicity, high absorption extinction coefficients, high fluorescence quantum yields, sharp fluorescence emissions, and resistance to photobleaching. All the good properties lead to the wide applications of BODIPY based compounds. In this research, two different kinds of BODIPY are synthesized. Firstly, BDBrC containing carbazole and BODIPY core is synthesized. Cellular uptake research shows BDBrC can target on lysosome and singlet oxygen generation research result indicates that BDBrC can be used in photodynamic therapy. BDBrC also shows pH-sensitive …

Washington State Community College Leaders: Perceptions Of The 2018 American Association Of Community Colleges Competencies For Community College Leaders, Teresa Mcdermott

Dissertations

Purpose: The two-fold purpose of this study was to understand how Washington state community college vice presidents, deans, and academic faculty members serve in leadership positions with the Washington Association of Community and Technical Colleges (WACTC) and the Faculty Association of Community and Technical Colleges (FACTC) rate the importance of the 2018 American Association of Community Colleges (AACC) Competencies for Community College Leaders, Third Edition and to compare the differences between the three groups’ views of the importance of the AACC competencies.

Methodology: A descriptive, non-experimental quantitative methodology was used for this study. The sample was 55 community college vice …

A Sequential Explanatory Mixed Methods Study Of The Strategies That Chief Human Resources Officers Use To Create A Culture Of Inclusiveness, Tonia Watkins

Dissertations

Purpose: The purpose of this sequential, explanatory mixed methods study was to identify and describe the leadership strategies that exemplary chief human resources officers (CHROs) of K-12 school districts use to create an organizational culture of inclusiveness using Kennedy’s (2008) 5 leadership qualities of cultural differences.

Methodology: This research study utilized quantitative surveys and qualitative interviews of 13 exemplary CHROs in Riverside, San Bernardino, and Orange counties in Southern California to identify and describe the strategies used to create an organizational culture of inclusiveness according to Kennedy’s (2008) 5 qualities of cultural differences.

Findings: The findings of the study reveal …

The Lived Experience Of Lebanese Oncology Patients Receiving Palliative Care, Myrna A. A. Doumit

Dissertations

The purpose of this study was to uncover the lived experience of Lebanese oncology patients receiving palliative care. The study design was based on the Utrecht School of phenomenology based on the Dutch school of phenomenology. This study followed purposeful sampling in which ten participants six women and four men with a mean age of 54.4 years were selected. The proposed research was approved by the Institutional Review Boards at the American University of Beirut and Duquesne University. In-depth semi-structured interviews along with observation-field notes were used as the source for data collection. Data were analyzed using the hermeneutic phenomenological …

A Comparison Of Two Debriefing Methods On Clinical Reasoning Outcomes, Learner Satisfaction With Debriefing And Reflection, Clinical Learning And Clinical Reasoning, And Psychological Safety Of Nurse Orientees In Simulation-Based Education, Lori A. Persico

Dissertations

Simulation-based education is a teaching method used successfully in military, aviation, and medical education; however, the evidence rarely indicates how debriefing affects the learners' experiences. Debriefing is an essential component of simulation-based education that fosters conceptual learning, critical thinking, and clinical reasoning. The purpose of this study was to compare the effects of two different debriefing methods on nurses' perceptions of psychological safety, satisfaction with development of clinical reasoning skills, and satisfaction with learning.

A Phenomenological Study Of Exemplary Charter School Executive Directors Leading From The Heart, Giovanna Arzaga

Dissertations

Purpose: The purpose of this phenomenological study was to describe how charter school executive directors lead from the heart using Mark Crowley’s 4 heart-led principles (building a highly engaged team, connecting on a personal level, maximizing employee potential and valuing and honoring achievements) to accomplish extraordinary results in their organizations.

Methodology: This study followed a qualitative phenomenological research study to describe the lived experiences of exemplary charter school directors. A sample of 8 charter school executive directors was selected from the target population that included Fresno, Ventura, Los Angeles, and Orange Counties in Central and Southern California. Each of the …

The Integration Of Art: A Multiple Case Study Of Science, Technology, Engineering, Art, And Math (Steam) Schools In Three Schools In Southern California, Reyna Esther Smith

Dissertations

Purpose: The purpose of this qualitative multi-case study was to describe and analyze how schools that implement a STEAM program include the arts in their integrated program. The study focused on 3 K-12 schools in Southern California that are located in the Antelope Valley high desert region of the state. This multi-case study analyzed an elementary school, a middle school, and a high school that are in different districts in the area.

Methodology: This multi-case study used qualitative data to analyze the research questions regarding art infusion in STEAM programs and teacher and leader perspectives. Drawing from interviews of teachers …

A Nationally Representative Survey Of Depression Symptoms Among Jordanian Adolescents: Associations With Depression Stigma, Depression Etiological Beliefs, And Likelihood To Seek Help For Depression, Latefa Ali Dardas

Dissertations

Arab adolescents are considered a particularly vulnerable population to depression. The substantial lack of mental health services and the stigma associated with mental illness on the one hand; and poverty, unemployment, and lack of reasonable hopes for a decent future in the context of corruption of regimes and perceived social injustice on the other, call for establishing committed and effective policies to tackle depression and its associated stigma among Arab adolescents at risk for or diagnosed with depression. However, there is a substantial lack of research that can inform the current profile of adolescent depression in the Arab region. We …

The Health-Related Quality Of Life Of Adults With Down Syndrome, Rebecca Jermyn Graves

Dissertations

The purpose of this study was to examine the health-related quality of life (HRQOL) and factors associated with the HRQOL of adults with Down syndrome (DS) as reported by adults with DS and their caregivers. The study was designed to compare measures of HRQOL, health problems, health risks, and health-care utilization of adults with DS based on self-report with those from caregiver-report and to explore associations between HRQOL and health problems, health risks, health-care utilization, adaptive behavior, and demographic characteristics.

Informing Effective Simulation Pedagogy In Nursing Simulation, Sherry L. Barnard

Dissertations

Simulation methods are now widely used in nursing education programs. Several studies have been conducted that examine the effect of simulation on student outcomes in learning (Alinier, Hunt, Gordon, & Harwood, 2006; Arnold, et al, 2009; Rosen, Salas, Silvestri, Wu, & Lazzara, 2008), however, little has been discovered regarding models of faculty support and guidance during simulation. The factors that influence student learning in the simulation experience suggest faculty be a guide by offering cueing and support before, during, and after the simulation process (Parsh, Roberts, & Green, 2010). It is also suggested that debriefing be non-judgmental and a time …

Simulated Presence Use For Quality Of Life Maintenance And Reduction Of Symptoms Of Distress In Persons Living With Dementia In Long-Term Care, Erin E. Bush

Dissertations

Nursing home residents with dementia often have an array of neuropsychiatric symptoms, including dementia-related agitation. It is theorized that many of these agitation symptoms occur due to unmet psychosocial needs that could be met by the presence of a caring nursing staff member, family member, or friend.

The purpose of this study was to determine whether live simulated presence improves dementia-related agitation when offered, identify barriers and facilitators to simulated presence between caregivers and residents of long-term care during the COVID-19 pandemic, and to determine if live simulated presence by a caregiver delivered one-on-one improved quality of life in long-term …

New Nurses' Experiences In The Lateral Violence Zone: A Grounded Theory, Mary Lillian Hanks

Dissertations

The impact of lateral violence on nurses and the nursing profession contribute to the nursing shortage and has negative effects on patient care (Vessey, DeMarco, Gaffney, & Budin, 2009). According to the Center for American Nurses (CENTER, 2008), lateral violence and bullying are an everyday occurrence among health care professionals. Nurses must gain real world experiences to deliver quality, safe, and effective patient care (Benner, Surphen, Leonard, & Day, 2010). Unfortunately, there are experienced nurses who are unable or unwilling to help novice nurses transition into their new role. Impaired relationships among nurses can lead to absenteeism, medical errors, and …

Exploring Resilience In Exemplary Rural School Superintendents, Silas Gaussoin-Radcliffe

Dissertations

Purpose: The purpose of this exploratory phenomenological study was to identify and describe the strategies used by exemplary rural superintendents to maintain personal resiliency based on Everly, Strouse, and McCormack’s (2015) five factors of personal resilience (active optimism, decisive action, moral compass, relentless tenacity, and interpersonal support).

Methodology: This exploratory phenomenological study used purposeful criterion sampling and recommendations from the county superintendents in the identified geographic area. Each of the 8 identified exemplary rural superintendents was interviewed using an instrument aligned to the five factors of personal resilience and their definitions. The researcher collected rich qualitative interview data, that were …

To Lift Or Not To Lift: An Institutional Ethnography Of Patient Handling Practices, Hans-Peter De Ruiter

Dissertations

The handling (lifting, mobilizing, moving etc) of patients is an integral part of the carework in health-care institutions. For obvious reasons, this puts healthcare providers at risk for musculoskeletal injuries (MSIs); furthermore the risk of such injuries has been considered an inherent risk of care work. In the last decade a concerted effort has been made to decrease (with the goal of eliminating) caregiver injuries by implementing safe patient handling programs (SPHP). These programs are presented as evidence-based algorithms that require the use of mechanical lifting devices. Institutions implement SPHPs as policies and procedural guidelines to which caregivers must conform. …

Quality Of Life Among Children With Physical Disabilities, Sharron E. Guillett

Dissertations

A triangulated descriptive research design was used to examine the relationships between quality of life (QOL), health status and physical disability among children between the ages of 8 and 15. A non-random sample (N = 80) of children with and without physical disabilities and their parents participated in this exploratory study. Children were asked to rank their quality of life from one to ten using a modified version of the Child Health Assessment Ladder (CHASL) (Norton, 1987) and then to discuss the rank they chose. QOL scores did not differ significantly between groups (M = 7 for both groups). Thirty …

Evaluating The Impact Of A Mindfulness Intervention On Mindful Attention And Awareness Resilience To Stress, And Perceived Stress In Newly Licensed Nurses In A Nurse Residency Program, Vicki L. Washington

Dissertations

A career in the healthcare profession of nursing provokes significant stress in newly licensed nurses. Previous studies suggested that mindful practice enhanced well-being by bringing awareness to thinking and living in the present moment (being mindful), decreased stress, and enhanced resilience to stress.

The purpose of this study was to evaluate the impact of a mindfulness intervention on mindful attention and awareness, resilience to stress, perceived stress, and health status in newly licensed nurses in a nurse residency program (NRP).