Digital Commons Network^™

Minimal Separating Sets In Surfaces, Christopher Nelson Aagaard

Dissertations and Theses

Given a connected topolgical space X, we say that L ⊆ X is a minimal separating set if removing L from X gives a disconnected surface, butremoving any proper subset of L leaves the surface connected. We classify which embeddings of topological graphs are minimal separating in an orientable surface X with genus g, and construct a computer program to compute the number of such embeddings, and the number of topological graphs which admit such an embedding for g ≤ 5.

Peer Group Influence On The Antecedents Of Academic Coping Over The First Year Of Middle School, Daniel Lee Grimes

Dissertations and Theses

The motivational model of academic coping provides a framework for investigating the motivational antecedents and social contextual influences on ways of coping with academic adversity during the transition to middle school. Two studies were conducted to investigate the roles of three motivational antecedent variables of academic coping: perceived control, autonomous motivation, and catastrophizing. Study 1 investigated relationships between the motivational variables and academic coping across the first year of middle school. Study 2 investigated peer group influences on the motivational variables and on academic coping. Data from an entire cohort of 366 sixth students in the only middle school in …

Improved Parameters Of Anand Model And Advanced Fea Technique For Low-Cycle Fatigue Life: Finite Element Analysis Models For Pb-Free Solder And Pb Solder In Real Life Ball Gird Ally Package, Hamidreza Nahavandi

Dissertations and Theses

The present study uses the finite element method to evaluate the fatigue life of solder joints of plastic ball grid array packages (PBGA) under thermal-cycling conditions. A Series of precise 3D FE models for solder joints of plastic ball grid array packages is created to improve reliability prediction accuracy. Damage parameters are obtained from the FEA results and used to estimate solder balls’ thermal fatigue life. The Coffin-Manson equation is employed. The predicted thermal fatigue lives are discussed in detail.

Due to marketing and legislative pressures, Pb-free solder is fast becoming a reality in electronic manufacturing. The industry has concluded …

Machine Learning Framework For Predicting Reliability Of Solder Joints, Robert Lee Jones

Dissertations and Theses

This paper presents the techniques and framework to produce an explainable machine learning model for predicting the reliability of solder joints exposed to thermal cycle testing. While machine learning techniques have become prevalent for many engineering and data analysis tasks, the complexity of the model occludes valuable information which can be used to refine the data, tune model parameters, and aid in scientific discovery. By exposing the relationships within the model, users can have greater confidence in the use and employment of it. The purpose of this study is to show how useful relationships can be obtained from a traditional …

Single-Stage Three-Phase Buck-Boost Dc/Ac Converter Design, Analysis, And Validation, Daisy Delgado-Zaragoza

Dissertations and Theses

Three-phase DC/AC power converters enable several applications including photovoltaic systems, electric traction inverters, uninterruptible power supplies, and utility systems. The classical three-phase voltage source inverter (VSI) topology only operates in voltage step-down or buck mode of operation. Increasing number of applications including transformer-less photovoltaic systems, battery cells, fuel cells, and traction motors require a wide range of input and output voltage range. Therefore, a DC/AC power converter topology capable of voltage buck and boost operation will enable wider operating range resulting in efficient and higher performance system designs. This thesis presents a single-stage bidirectional power flow DC/AC inverter topology capable …

A Native American Perspective On Navigating The Academic World With Resilience And Honoring The Wisdom Of Native Elders, Shani Renee Johnson

Dissertations and Theses

The graduation percentage among Native American students has consistently remained at a discouraging 50 %, both in the past and at present. This study employed a narrative inquiry approach to investigate the low graduation rates among Native American students, from the perspective of a Native American educator and mother. This study examined the historical trauma and colonization experienced by Native Americans and how it has affected Native American families and communities, resulting in low rates of graduation among Native students. In addition, this study examined factors contributing to resilience by acknowledging Traditional Ecological Knowledge (TEK) and Indigenous Ways of Knowing …

Participatory Democracy: The Potential For Civic Transformation Understanding Participants' Learning In The Milwaukie Citizens Jury, Amanda Grace Hudson

Dissertations and Theses

Faced with unresponsive government institutions and the limitations of representative democracy, participatory and deliberative democrats have created alternative models for robust democratic participation such as civic juries, civic assemblies and participatory budgeting. Advocates claim that these methods create better citizens and better outcomes and they claim these forums act as a school of democracy. The schools of democracy theory describes participation as a virtuous circle--that doing democracy will make people more democratic. While these processes often produce enthusiastic supporters and encouraging results, there has been very little research to date that attempts to explain how and why people learn and …

Pathways To Social Mobility: Examining Trades As A Career Path For Formerly Incarcerated Individuals, June Jenkins

Dissertations and Theses

Obtaining stable, paid employment is crucial for successful reentry into the community after incarceration, however, formerly incarcerated individuals face extensive barriers when entering the workforce. Trades may present a uniquely attainable career path for this population due to relatively low barriers to entry. To date, there is a lack of research investigating experience-based perspectives on the viability of trades training programs and trades careers in facilitating prisoner reentry. This study employs semi-structured qualitative interviews to investigate perspectives on trades as a career path for formerly incarcerated individuals as well as barriers to accessing and attending trades training programs. Interviewees include …

Improving Biomimetic Passive Dynamics Of A Quadruped Robot Hind Leg Hip Joint With A 3d Printed Torsion Spring, Haonan Zheng

Dissertations and Theses

The Agile and Adaptive Robotics Lab is interested in researching the neuromuscular control network of legged animal locomotion. To validate the lab's understanding of biological neural control, synthetic neural networks are developed and applied to biologically inspired legged robots. For a synthetic neural network to operate in the same manner as a biological neural network and produce the same locomotor behavior, the robot that the synthetic neural network is controlling must also mimic its biological counterpart. Previous research produced a quadruped robot hind leg designed with biomimetic passive dynamics by installing spring and damper pairs at each joint, however, an …

Acquisition Of Spatial And Temporal VTe-Kuru By Learners Of Japanese At A University In The U.S., Ayumi Naraoka

Dissertations and Theses

This study examined to what extent Japanese as Foreign Language (JFL) learners have mastered the grammatical pattern for the verb gerund + kuru ("come"), which is referred to as Vte-kuru henceforth. There are two types of Vte-kuru: (1) the spatial Vte-kuru, meaning "to do [something] and come back," and (2) the temporal Vte- kuru, meaning "begin to." It is assumed that learners did not use Vte-kuru often, even though they should have learned two uses of Vte-kuru by the end of their 200-level Japanese class. To find out to what extent …

Seguir Adelante: A Qualitative Exploration Of Latino Farmworkers' Work And Non-Work Resources, Faviola Robles Saenz

Dissertations and Theses

Precarious work sectors within the United States have relied on Black and Brown labor for many decades. More specifically, Latino immigrant workers have been an exploited community within many dangerous workforces but especially within the agricultural industry. They are a crucial population for the labor and economy of the U.S., yet Latino farmworkers report feeling expendable, being discriminated against, and being exposed to hazardous working conditions. Due to these experiences, scholars have explored the role non-work resources have in providing support for this community, their social networks being especially beneficial for them. However, research on the links between their work …

Synthesis And Computational Studies Of Α- And Δ-Substituted Macrocyclic Europium And Ytterbium Complexes, Delainey Amara Winder

Dissertations and Theses

The uses of macrocyclic lanthanide complexes are vast, with many targeted MRI contrast agents at the forefront of the field. Many of these are ParaCEST agents, which require exchangeable protons accessible on the macrocycle and the slow exchange of coordinated water molecules. The substitution at both the α- and δ-carbon on the amide pendant arm of these macrocyclic lanthanide complexes can lock bulky groups on the δ-carbon to a pseudo-axial position. When the α- and δ-carbons have the same chirality, the bulky group will be pseudo-equatorial, and when the chirality is opposed, the bulky group will be pseudo-axial. By performing …

Centering The Leader: An Investigation Of Leader-Centric Variables In The Support Provision Process, Jordyn Jan Leslie

Dissertations and Theses

Few studies to date have investigated leader-centric variables associated with the support provision process. The following dissertation includes three studies that attempt to further understand such relationships. In Study 1, the interaction between leader sleep quantity and quality on various types of leader support (e.g., general supervisor support, family supportive supervisor behaviors, and sleep leadership) is studied using both employee and leader ratings. Study 2 integrates leader-centric research with work-life supportive leadership to propose a new theoretical model that delineates leader-centric variables (e.g., health & well-being, skills, role expectations, job demands) as precursors to the provision and perception of work-life …

The Effects Of Physical Accessibility And Subjective Accessibility On Grocery Shopping Behaviors In Oakland, California, Huijun Tan

Dissertations and Theses

Existing studies underscore the complexity of urban accessibility, defined by a range of factors, including the city's physical layout and infrastructure as well as the subjective perceptions and experiences of its inhabitants. As urban areas continue to grow and diversify, gaining a comprehensive understanding of these varied interactions is imperative. This broader context highlights the necessity of investigating the interplay between physical and subjective accessibility, aiming to illuminate the specific challenges and opportunities faced by these communities in accessing necessary services. This study explored the relationship between physical and subjective accessibility and their consequential impact on grocery shopping behaviors among …

Large Length Scale Droplet Capillary Phenomena: Generation, Jump, And Capture, Karl Jeffrey Theodore Cardin

Dissertations and Theses

Understanding the life cycle of droplets, from generation to capture, for example, is critical to understanding environments from the air-sea interface to the indoor environment of the International Space Station. Investigations have been performed in this work to provide insight into three droplet phenomena, each ubiquitous in both terrestrial and microgravity settings, through a lens of capillary flow. Each investigation attempts to disentangle the effects of gravity from the effects of surface tension. A drop tower test campaign is performed for each of the three investigations. Models are developed and simulations are performed to rationalize the observations. Each investigation is …

Dynamic Social Ecologies Of Students' Motivational Resilience: The Complex Relationship Between Family, Teacher, And Peer Support, And Students' Academic Coping And Reengagement, Kristen Elizabeth Raine

Dissertations and Theses

Drawing upon self-determination theory (SDT) based models of motivational resilience, the following dissertation contains three studies that expand upon the current literature by investigating how processes of motivational resilience, or children's general capacity to handle the everyday academic stressors they encounter at school, are connected to the complex social ecologies created by the intersecting contexts of school and home. Study 1 examined whether family motivational support predicted increases in student reengagement through its effect on subsequent levels of students' self-system processes of relatedness, competence, and autonomy in a sample of 590 early adolescents from an urban middle school in the …

Exploring The Social Processes Influencing The Well-Being And Social Integration Of Systemically Marginalized Students In Higher Education: A Mixed-Methods Approach, Zeinab Abbas Hachem

Dissertations and Theses

Comprising two manuscripts, this dissertation employs a mixed-methods approach to comprehensively examine the intrapersonal and interpersonal processes influencing the socioemotional well-being and social integration of systemically marginalized students. The first manuscript quantitatively explored the relationship between ethnic identity commitment and indices of well-being, the mediating role of social relationships, and the moderating roles of gender and immigrant generation status among Latinx college students (N = 707). Results suggested that ethnic identity commitment was positively associated with socioemotional well-being. Although both types of relationships were significant mediators on their own, maternal (vs. peer) relationship quality was the stronger mediational influence. Furthermore, …

Adopting Oer Course Materials: Instructor Experiences, Jenny Ceciliano

Dissertations and Theses

Traditional commercial textbooks used in postsecondary courses are often problematic due to their rigidity, tendency to mirror the dominant culture, and the substantial cost imposed upon students. Although replacing these texts with open educational resources (OER) can facilitate more equitable and inclusive pedagogical practices while removing a significant expense, there has been insufficient research surrounding instructors' experience of transitioning from a commercial textbook to OER course materials. Through semi-structured interviews with nine postsecondary instructors who teach with OER course materials, this basic qualitative study explores the experience of that transition. The findings indicate that adopting OER is a challenging and …

Crossover Of Supervisors' Perceptions Of Co-Worker Support To Employees' Well-Being, Shalene Joyce Allen

Dissertations and Theses

This study expands scholarly understanding of the positive impact of supervisors' perceptions of support on employee work-family and well-being experiences. Specifically, this study examines the role of resource-based positive crossover from supervisors' perceptions of co-worker support behavior to their employees. The current research draws on Systems Theory to understand the context, Conservation of Resources Theory to understand the type of resource purported to position individual resource gains, and crossover-spillover theory to understand the process through which resources crossover from supervisor to employee. Based on prior theory, this dissertation investigates a positive crossover effect of supervisors' perceptions of co-worker support at …

Exploring Evidentiary Approaches And Reform Potential In The Allies In Change Program For Abusive Intimate Partners, Julie Melissa Conner

Dissertations and Theses

This thesis examines the Allies in Change batterer intervention program, analyzing its curriculum components, alignment with evidence-based practices, unique features, limitations, and implications for domestic violence intervention. The study employs a qualitative mixed-methods approach, including curriculum textual analysis, word frequency count, a semi-structured interview with Chris Huffine, the curriculum author and program founder, and observation of a forty-hour domestic violence training provided for batterer intervention programs and facilitators.

The research begins by reviewing the literature on domestic violence intervention, highlighting the importance of evidence-based practices, cognitive behavioral techniques, and cultural responsiveness. It then conducts a textual analysis of the Allies …

Marketing In Higher Education: The Effects On The College Choice Experience Of First-Generation Latinx Students, David Cortez

Dissertations and Theses

The Latinx population in the United States has drastically increased over the last twenty years. During the same period, the number of first-generation Latinx students enrolling in higher education post-recession has also increased by as much as 1.5 million students. The expansion of the Latinx student population in Oregon has mirrored the national trend by exponentially increasing over the last 10 years. As the population of first-generation Latinx students grows, it becomes essential to explore the issues and barriers Latinx students face in making their college choices. Previous researchers have found that selecting the right institution is important to increase …

Concolic Testing For Scripting Languages, Zhe Li

Dissertations and Theses

Scripting languages, such as JavaScript and Lua, are becoming more and more popular. They are typically easy to learn and use, making them accessible to a wide range of developers, even those with limited programming experience. Lua, for instance, is a lightweight, efficient, and versatile scripting language. It is designed to be easy to integrate into other systems and is often used as an embedded scripting language in larger applications such as NMap, which is a network scanning tool.

As another example, web front-end development with JavaScript (JS) is a popular choice for developers due to its ability to add …

Dietary Saturated Fatty Acids Modulate Host Innate Immunity, Amy Lorraine Seufert

Dissertations and Theses

Nutrition, cellular metabolism, and inflammatory regulation of the immune system are interconnected, and advancing our understanding of this will greatly improve treatment of metabolic and inflammatory disease. Specifically, dietary saturated fats are becoming increasingly appreciated for their ability to modify innate immune cell function in mammals following absorption into the blood and lymphatic circulation systems. The work herein focuses on the capacity for lipids in the diet to modulate innate immune memory. My thesis first broadly outlines fundamental background, including: the evolution of human nutrition, the discovery of innate immune memory, and key topics that reoccur throughout the text surrounding …

An Examination Of The Impact Of Court-Appointed Fines And Fees: How Governmental Reliance On These Expenses Is Harming Vulnerable Communities, Rachel Elizabeth Couche

Dissertations and Theses

Fines and fees are commonplace in the United States criminal justice system as a form of punishment for both minor and severe offenses. While substantial research has demonstrated that these financial consequences disproportionately affect certain communities, studies that depict a narrative of these impacts are vastly underrepresented in the field. This project expands upon past literature by delving into the effects of these practices on individuals and their families. The current study outlines the findings from a content analysis of twelve semi-structured interviews on the impacts of fines and fees in Oregon. The findings create a deeper understanding of how …

Prosodic Analysis Of Wh-Indeterminate Questions In L2 Korean, Jung In Lee

Dissertations and Theses

Wh-indeterminate questions in Korean are potentially ambiguous due to the limited use of morpho-syntactic markers. When an explicit morpheme indicating the question type is not used, the disambiguation of the question relies, primarily, on prosodic cues. Drawing from previous studies of L1 Korean, this study examines the production and perception of intonation patterns of English L1 learners of Korean for wh- and yes-no questions in Korean. That examination allows speculation on potential L1 influence in the learners' production. Five English L1 learners of Korean who received formal instruction in Korean at a U.S. university completed a production and perception test …

An Analysis Of Citizen Participation In Spatial Plan Preparation, Case Study Of Gaborone City, Botswana, Bongani Tshidiso Ikaneng

Dissertations and Theses

In the dynamic field of urban planning, the significance of citizen participation in shaping spatial plans has grown substantially. Research exploring the significance of public participation in planning has become increasingly vital, highlighting the need to understand citizen’s contributions to the planning process. This study investigates the community engagement experiences of citizens in the development of a local plan, with a focus on Gaborone City, Botswana. With data that was collected through online interviews through Zoom, conducted in twelve neighborhoods between March and April 2024, which were recorded and transcribed, the study presents challenges articulated by residents about their participation …

Culture Or Power: The Eruption Of The Anglophone Crisis In Cameroon, Danielle Tagakou Talla

Dissertations and Theses

Located in Central West Africa, Cameroon has been the stage of a protracted conflict since 2016. The conflict called the "Anglophone crisis" is rooted in Cameroon colonial history. This is reflected in the composition of its population with a large majority of Francophones and only 20 percent of Anglophones. The subsequent thesis aims to examine the crisis between 2016 and 2022 and understand the shift in focus that happened in the early years of the conflict. Using a qualitative methodology, journal articles, books and recorded interviews will provide substantial sources to decipher the change from cultural focus to one of …

Cleaning The Dirty Pool: Testing Interaction Effects Using Different Panel Model Specifications, Rhiannon Berry

Dissertations and Theses

This exploratory study seeks to uncover the most effective approaches for constructing interaction terms within panel models. With no preconceived hypothesis in mind, the primary aim is to discern which modeling configuration yields the most robust results, laying the foundation for future research in statistical modeling. Using a large data set of sentencing reforms passed between the mid-1970s and mid-2000s, this study systematically assesses interaction terms and determines the most appropriate modeling. Different specifications of sentencing reforms at the state level within different modeling specifications will be explored to highlight which models are most appropriate in predicting imprisonment rates. By …

Bridging The Gap: Using Significance Modeling To Identify Data Gaps In Lithic Sites Within The Tualatin River Basin, Aaron James Reid Hood-Foster

Dissertations and Theses

Archaeologists commonly evaluate National Register of Historic Places (NRHP) eligibility for precontact sites in Cultural Resource Management archaeology under Criterion D. This focus on Criterion D can create the false paradigm that precontact sites are only significant by virtue of their information potential. This paper explores precontact sites in the Tualatin River Basin in northwestern Oregon and identifies some key deficiencies in the ways those sites are recorded and documented by archaeologists. This paper then discusses the development of a geodatabase of site attributes and a significance model with contributions and feedback from relevant parties and Tribal representatives.

The geodatabase …

Applying Decolonizing Theories And Methodologies In Archaeology To Two Collaborative Cultural Resource Management Projects, Cydney K. Lanthier

Dissertations and Theses

Decolonizing theories and methods were employed during two separate graduate research projects. The methods of the initial project were informed by political ecology, the landscape-level historical ecology theory, Tribal sovereignty, traditional ecological knowledge (TEK), Indigenous archaeology, and community based participatory research (CBPR). The initial project was based entirely on CBPR and purposed to gain National Register of Historic Places (NRHP) nomination as a Traditional Cultural Property (TCP) over a portion of the traditional landscape. This project was cancelled before completion. However, several methods involved in CBPR were employed before then. The second project took on more of the historical ecology …