Digital Commons Network^™

Not Merely A Workaround: Theorizing Asynchronous Math Talks As A Robust Instructional Routine For Visible Thinking, Participation, And Engagement In Mathematics Teacher Education, Simon Byeonguk Han

Dissertations and Theses

The sudden global shift due to COVID-19 accelerated the need for a better understanding of mathematics learning and teaching in an asynchronous format. Also, despite the popular use of mathematics instructional routines in mathematics classrooms, the field of mathematics education research has very limited empirical studies on instructional routines. This dissertation addresses this by examining Asynchronous Math Talks (AMTs), a structured instructional routine adapted from Number Talks. The central goal of this research is to develop and theorize AMTs not merely as an online workaround, but as a robust instructional model that leverages the unique affordances of digital platforms to …

Factors Influencing Non-Perennial Stream Initiation In The Mt. Hood National Forest, Allison Bast

Dissertations and Theses

Historically, non-perennial headwater streams have been overlooked due to their small size and infrequent flow regimes, often leading to them not being recognized as legitimate streams, despite scientific evidence that has shown these streams significantly affect the quality of downstream waters. To combat this issue, environmental managers need to be able to accurately identify and delineate the origins of these streams; however, despite decades of research, an accurate, universal method for predicting how and where these streams commence has yet to be developed. Early studies conducted in steep, humid environments, identified a strong inverse linear relationship between the size of …

Comparative Analysis Of Bacterial Recbcd And Sbcc-Sbcd Systems And The Yeast Mre11-Rad50 Complex During Dna Replication, Tannos Seyedjavadi

Dissertations and Theses

Accurate completion of DNA replication when forks converge is essential for genome stability. In Escherichia coli, several proteins have been identified including RecG, ExoI, RecBCD, and SbcCD, that contribute to completing replication, and loss of these factors causes genetic instability. Eukaryotes encode proteins with homology to several E. coli completion enzymes. Mre11–Rad50 complex is structurally and functionally conserved with bacterial SbcCD, and Rrm3 shares homologous motifs with bacterial RecBCD. These proteins are often described as being involved in homologous double strand break repair. Whether they are also conserved and play a similar role as their E. coli counterparts in …

Degree Assortativity And Estimation Of Degree Distribution In A Contact Network Of People Who Inject Drugs, Peter Geissert

Dissertations and Theses

This dissertation analyzes data from a respondent driven sampling (RDS) study of people who inject drugs in Portland, OR.  The objective was to assess assumptions for the use of weighted estimators to estimate a population physical contact (syringe sharing) network degree distribution.

Visualization of degree distribution for social and physical networks, Kolmogorov-Smirnov tests of difference, and kernel tests of equivalence were used for comparison of distributions. Spearman's rho and GAM non-parametric regression models were used to test for association and assess non-monotonic relationship. The validity of Markov chain assumptions for RDS was assessed using a transition matrix, Markov chain graphs, …

God's Not Neutral: Narrative Tropes, Spiritual Warfare, And The Construction Of Evangelical Political Identity In American Christian Fiction, Evelyn L. Mccullough

Dissertations and Theses

Evangelical Christian fiction has reached tens of millions of readers and viewers during the most sustained period of evangelical political mobilization in American history, yet its narrative construction remains largely unexamined. This study asks how recurrent tropes in this genre build the attitudinal and emotional preconditions for political engagement. Combining systematic qualitative content analysis of eight texts spanning four decades (1986–2024) with Critical Discourse Analysis grounded in van Dijk's sociocognitive framework, it traces how storytelling devices connect theological belief to political behavior. The analysis reveals a single organizing logic: the corpus holds one regressive heroic disposition constant while making it …

Extending W-Event Differential Privacy To The Publish-Subscribe Framework, Jacob Jerome Olinger

Dissertations and Theses

Internet of Things (IoT) devices have become ubiquitous, permeating both enterprises and homes, and they increasingly rely on publish-subscribe (pub-sub) frameworks that give subscribers real-time, high-fidelity access to device data. For privacy and confidentiality, however, today's pub-sub systems largely stop at channel-level authentication, encryption, and access-control lists. These protect data in transit and restrict who may receive it, but place no quantitative limit on what a subscriber with legitimate access to messages can infer about its publishers.

We close this gap by extending w-event differential privacy to the pub-sub setting. We generalize it from count queries to any aggregate …

Northern Red-Legged Frog Terrestrial Movement And Connectivity In A Fragmented Peri-Urban Landscape, Alyson W. Yates

Dissertations and Theses

The movement and spatial ecology of amphibians is largely understudied, despite their imperiled conservation status. Landscape fragmentation by roads and other anthropogenic development features are known to affect amphibians in multiple ways pertaining to movement, often leading to population declines and exacerbating extinction risk. To mitigate these factors, wildlife managers can implement multidisciplinary strategies that seek to preserve or restore functional connectivity. However, these efforts require strong fundamental knowledge of how a species interacts with complex landscapes throughout their life cycle, including through their movement.

My thesis investigates multiple facets of northern red-legged frog (Rana aurora) spatial ecology …

Inherited Local Shrinkage For Adaptive Functional Form Discovery, Jacob Colestin Schultz

Dissertations and Theses

Statistical models frequently employ nonlinear effects, interactions, and multiresolution basis expansions to represent complex relationships between predictors and responses. Determining the appropriate level of model complexity, however, remains a fundamental challenge. This dissertation introduces Inherited Local Shrinkage (ILS), a Bayesian global-local shrinkage framework for adaptive functional form discovery that enforces strong heredity among hierarchically related predictors.

ILS propagates shrinkage through directed acyclic graphs representing predictor inheritance, ensuring that increasingly complex terms are retained only when supported by simpler parent structure. The framework applies broadly to polynomial regression, interaction models, wavelets, splines, and other hierarchical basis expansions, while naturally extending to …

Omoiyari In The Performance Of American Learners Of Japanese: An Analysis Of Second Culture Compilation And Pragmatic Transfer, Shizuka Fukuo

Dissertations and Theses

This thesis examines omoiyari (consideration for others) as a Japanese cultural theme by examining how it is enacted by native Japanese speakers and American learners of Japanese during an invitation scenario. L2 learners' incorporation of the target culture's linguistic and behavioral norms is essential to fully participate in ways that read as natural in that culture. However, relatively little research has examined the extent to which L2 learners are able to enact culturally embedded norms in L2 interaction. Furthermore, little attention has been paid to explaining the cultural theme of omoiyari as it is enacted in an invitation role-play provides …

Representing Post-Fire Reality: An Empirically Informed Temperature Index Approach To Post-Fire Hydrologic Modeling In Oregon's Western Cascades, Logan Hastings

Dissertations and Theses

The invaluable water resources stored in snowpack face mounting threats from rising temperatures, drought, shifts in precipitation regimes, and increased fire frequency, which pose challenges to operational hydrologic modeling in Oregon's sensitive maritime snowpacks. The gridded temperature index (GTI) approach in operational models like the Hydrological Engineering Center's Hydrologic Modeling System (HEC-HMS) from the U.S. Army Corps of Engineers remains in common use for its minimal data requirements, but how GTI parameterizations should adapt to post-fire conditions is largely unknown.

This research assessed the impact of the 2020 Lionshead Fire on HEC-HMS performance in the North Santiam River basin across …

Insurance: A Hidden Tool In The Fire Adapted Community Toolbox?, Michael Patrick Wilshire

Dissertations and Theses

Increased costs associated with wildfire activity in the Western United States has raised concern about the long term stability of homeowners insurance. One popular approach to reducing the risk of catastrophic wildfire is the completion of Firewise behaviors on residential properties. I explored homeowner experiences with homeowners insurance, and asked if rising insurance premiums and policy non-renewals are affecting homeowners' Firewise behaviors. I surveyed homeowners living in the Wildland Urban Interface (WUI) in Deschutes County, Oregon to understand their experiences with homeowners insurance, past Firewise actions, and intentions to complete Firewise actions in the near future. Most homeowners surveyed have …

Unmanned Aerial Support Program In Portland Police Bureau: A Case Study, Eiryn Renouard

Dissertations and Theses

With the Portland Police Bureau (PPB) adopting drone technology in 2024 as a tactical tool, officers have begun to experience change in the way they approach their roles as they learn to work in conjunction with this new technology. Known as the Unmanned Aerial Support program (UAS), this drone program is embedded into PPB's patrol unit. The recency of the program offers an opportunity to examine how a new program using new technology builds its culture and impacts the perspectives and behaviors of its participating officers. By interviewing officers and conducting field observations of the officers and drones in action, …

Spatial Reconstructability Analysis: Information-Theoretic Modeling Of Categorical Raster Data, David Percy

Dissertations and Theses

This research focuses on the application of Reconstructability Analysis (RA), an information-theoretic machine learning (ML) methodology, to categorical spatial data in Geographic Information Systems (GIS). RA was developed in the systems community with applications including classification, prediction, pattern recognition, and decision analysis. RA is implemented in OCCAM (Organizational Complexity Computation and Modeling), a software suite developed at Portland State University that analyzes discrete data in tabular form, with observations in rows and variables in columns. While RA has been successfully applied to a variety of domains, no systematic application to georeferenced raster data arranged in regular grids has been previously …

Near-Field Acoustic Microscope With Normal Force Metrology Capability, Kacharat Supichayanggoon

Dissertations and Theses

This dissertation introduces quartz tuning fork (QTF) based Shear-force Near-field Acoustic Microscopy (SANM) and Whispering Gallery Acoustic Microscopy (WGAS) systems, upgraded this time with Atomic Force Microscopy (AFM) capability to also monitor the vertical force component involved in shear force interactions. This enhanced system aims at studying nano-sized confined fluids under shear, with an emphasis on finding correlations between the fluid's a) viscoelastic properties and b) near-field acoustic wave emission capability. In the current SANM/WGAS/AFM system addressed here, the confined fluid is constituted by the water meniscus that bridges the gap between the apex of a laterally …

Developing Field And Spaceflight Microscopy, Nikki Johnston

Dissertations and Theses

Designing for spaceflight favors the reduction of unnecessary features and cost-cutting, whether thisbe computation, hardware, or procedure. Resources are spent toward fortification and mission success over convenience. Such design goals paired with the relatively smaller budgets of academia lead us to do as much as we can in-house and use open-source as much as we can without compromising mission success. We also believe that thoroughly testing technology in extreme environments on earth is necessary for the success of a flight instrument. We focus on microscopy for life detection. I have spent my time here learning methods of hand-building microscopes to …

Shade Tree Democracy: Maintaining Peace In Post-Conflict Societies, Jaafar M. Sh Jama

Dissertations and Theses

Under what conditions does customary law contribute to maintaining peace in post-conflict societies? I study this question in the context of Somalia, a country that has lacked an effective central government since the outbreak of civil war in 1991. I argue that in the wake of civil war, traditional systems of government are capable of facilitating peace whereas governance by the modern state apparatus is often an impediment to peace. The underlying mechanisms that I argue explain the effectiveness of a traditional system of governance are that it is 1) in tune with broadly-held societal values, 2) intuitive for citizens …

Trapped In Transition: Structural Change And Political Dynamics In Middle-Income Countries, Gabriel Duvidovich

Dissertations and Theses

The middle-income trap literature has examined why relatively few middle-income countries transition to high-income status. A range of explanations has been proposed, but the political dimension has often been overlooked. Studies that take a political perspective often focus on institutional form rather than the state’s ability to effectively implement policy. This study addresses this gap by bringing political capacity to the center of the analysis. It argues that political capacity appears important for the productive upgrading required for sustained growth in middle-income economies and shapes economic growth trajectories across countries at different income levels.

The empirical analysis uses country-period panel …

Advancing The Oresat Adcs: Design & Implementation Of An Open-Source Reaction Wheel System, Chris Kane-Pardy

Dissertations and Theses

Reaction wheels provide the primary means of precision attitude control for many CubeSat attitude determination and control systems by exchanging angular momentum with the spacecraft body. As the Portland State Aerospace Society's OreSat spacecraft transitioned from a 2U to a 3U configuration, the increased spacecraft inertia reduced the attitude control authority available from the legacy reaction wheel system. This thesis addresses that challenge through the redesign of the reaction wheel system and the development of a deterministic embedded controller and experimental framework for evaluating brushless motor commutation strategies under identical operating conditions.

The redesigned system combines an analytically sized flywheel, …

We Don't See Race, We See Blue: A Case Study Of Police Unions As Racialized Organizations, Sarahfina Aubrey Peterson

Dissertations and Theses

In the late 1960s, police began to unionize. Today, they are the most well-organized labor force in the United States, with 70% to 80% of sworn officers now represented by a union. Though it has been decades, little scholarship has developed about how police unions affect policing. Much of the research that does exist uses race-neutral frames to address an organization steeped in racial history. This study aims to address this gap in scholarship, in part, by introducing race as a motivation for and explanation of organizational output.

This research applies Victor Ray's racialized organizations theory to police unions. I …

Integrative Evidence For Cryptic Diversity In The Thomomys Mazama Species Complex: Phylogenetics, Cranial Morphometrics, And Ecological Niche Modeling, Jessica Kate St. Michael

Dissertations and Theses

The population genetic structure and geographic distribution of the pocket gopher genus Thomomys Wied-Neuwied, 1839, lends itself to speciation events. Conserved morphology, ecological specialization, and high rates of molecular evolution may increase the probability of allopatric speciation, thereby contributing to the presence of morphologically cryptic taxa. In light of these patterns of evolution, we assessed genetic divergence and phylogenetic relationships, cranial morphometric differentiation, and ecological divergence among taxa in the Thomomys mazama species complex to test the hypothesis that T. mazama is a single species. Species delimitation analysis using Bayesian Poisson Tree Processes (bPTP) and data from the mitochondrial cytochrome …

Temperature And Hydrologic Context Influence Methane Variability In A Low-Salinity Marsh, Zoie Brauser

Dissertations and Theses

Coastal wetlands are biogeochemical hotspots that capture and transform carbon and nutrients. Wetland restoration is increasingly used as a climate mitigation strategy because of wetlands' capacity to sequester large amounts of carbon. However, low-salinity tidal marshes exhibit high variability in methane (CH₄) emissions, which could partially offset carbon sequestration under certain conditions. Understanding the drivers of CH₄ variability is crucial for restoration and conservation work. This project uses an observational research approach to assess the relationships between environmental factors and carbon dioxide (CO₂) and CH₄ soil gas fluxes in a restored low-salinity tidal marsh …

Intrinsic Memory In Digital Snns: Enhancing Performance On The Cart-Pole Task With Fractional-Order Dynamics, Niklas Karl Anderson

Dissertations and Theses

Researchers working with Spiking Neural Networks (SNNs) are faced with the challenge of identifying useful biologically plausible features for inclusion in neuron models. Prior research indicates that dynamics of fractional-order calculus, which impart a form of intrinsic memory, are a key feature of biological neurons. In this work, we present the development and usage of neural networks with intrinsic memory in application to the cart-pole task, a common benchmark for neural network performance. We found that usage of fractional-order neurons may allow for up to a 37.5% reduction in neural network size as compared to networks using a standard Leaky …

Set-Valued Conjugate Calculus And Duality In Optimization And Machine Learning Via Generalized Relative Interiors, Gary Lee Sandine

Dissertations and Theses

Convex analysis, optimization, and duality theory are broadly applicable to a multitude of real-world problems. Theoretical frameworks ensuring strong duality and optimality are fundamentally tied to convex separation under qualification conditions frequently involving topological or relative interiors. These can be empty in convex sets that appear naturally in infinite-dimensional models, yet guarantees of optimality and strong duality are often attainable. This dissertation presents frameworks for applying convex separation via generalized relative interiors to develop generalized calculus rules as well as conditions for strong duality and optimality for infinite-dimensional constrained convex optimization problems.

The first major contribution is the introduction of …

The Influence Of Urban Form On The Distribution Of Air Pollutants, Takin Khosrownia

Dissertations and Theses

Urban form exerts strong control on how pollution from outside a city is transported through the urban canopy and experienced at street level. This study uses the prognostic microclimate model ENVI-met to simulate an active pollutant released from an upwind rural highway and advected through an urban region represented by ten Local Climate Zone (LCZ) types. The cases share identical inflow and are isothermal, dry, and non-vegetated, so that differences among them are attributable to building morphology alone. PM2.5 is the primary exposure diagnostic. Its transport and ejection are characterized through plan-view contours, vertical plume sections, and spatially averaged streamwise …

Experiences Of Psychological Recovery From Work In Second-Generation Asian Americans, Laura Yang

Dissertations and Theses

Individuals of Asian descent make up approximately 7.4% of the U.S. population. As one of the fastest-growing minority groups, their population is projected to reach nearly 15% by 2065, with 38% being foreign-born – surpassing all other racial minority groups. Despite their increasing presence in the U.S. workforce, research on Asian workers' nonwork experiences remains limited. One key unexplored area is how Asian workers engage in recovery after work, considering their unique cultural and racialized experiences. Drawing on literature examining psychological recovery from work, this qualitative study employed multiple methods of analysis, both listening guide method and thematic analysis, to …

Functionality Risk Assessment And Risk-Based Management For Critical Infrastructure Systems, Anteneh Zewdu Deriba

Dissertations and Theses

Critical infrastructure systems such as transportation networks serve as the lifelines of modern society, supporting economic activity and ensuring access to critical services. Their disruption under extreme events can produce consequences extending far beyond physical damage to individual assets. In transportation networks for instance, failures of critical assets such as bridges and tunnels can reduce accessibility of communities, limit freight capabilities for commerce, and increase travel distance and travel time of road users. These consequences associated with the system functionality loss are tied not only to the physical vulnerability and failure of individual assets, but also to the system configuration …

Measurement Of Pollution Emissions From Natural Gas Stoves: Preparation For An Induction Cooktop Intervention Study, Jessica Zanella Lorensi

Dissertations and Theses

Humans spend ∼90% of their time enclosed in buildings. Indoors environments can be a source of pollutant which can affect health and productivity. Appliances that combust fossil fuels indoors, like stoves, are a critical source of a range of pollutants, like carbon monoxide (CO) and nitrogen dioxide (NO₂). In the US, the usual cooking fuel is natural gas (NG), presented in more than 30% of households in the country. Some studies in the literature linked cooking pollutants, including those specific to gas combustion, to various health conditions, including heart and respiratory diseases. Nitrogen dioxide, for example, can be …

Improving The Fpga Radio Design Cycle: Implementing Dvb-S2 Modulation Using Verilator And Gnu Radio, Seth Pellegrino

Dissertations and Theses

In embedded digital radio systems, a central challenge is meeting the real-time throughput required to process the samples--especially for space-bound ultra-wideband SDRs which must handle more than 100 Gbps entirely onboard. An FPGA's programmable logic offers sufficient potential, but realizing a particular radio flow is a project usually fraught with defects and long turnaround times. We simulated Verilog modules in a custom harness that adapted a Verilated model to GNU Radio, which allowed for breaking down a complicated radio flow (here, DVB-S2 modulation) into a series of well-bounded problems each with clear criteria for success. The framework, built on open …

Identity, Needs, And Conflict Online: Understanding Cultural Fragmentation In The Black Diaspora, Imhile Omosede Dora Akpata

Dissertations and Theses

This study examines how identity formation, intra-diaspora tensions, and social media interactions contribute to fragmentation within the Black diaspora. While existing scholarship, including work by Godfried Asante and Elizabeth Chacoko has emphasized the fluid and socially constructed nature of Black identity, less attention has been given to how these processes operate in practice across diverse diasporic groups and how they are intensified in digital environments. This research addresses this gap by analyzing how individuals negotiate Black identity, how tensions emerge within the diaspora, and how social media shapes and amplifies these dynamics.

Drawing on Social Identity Theory developed by Henri …

Thermal Sensitivity Of Native And Introduced Crabs: Implications For Reproductive Success, Keria Moritsugu-Vandehey

Dissertations and Theses

Temperature is a major driver of physiological and developmental processes in marine organisms, and continued climate warming is expected to affect reproduction and recruitment in estuarine species. Early life stages are often particularly sensitive to environmental stress, yet relatively little is known about how warming influences embryonic development, hatching success, and larval survival across co-occurring native and introduced crab species.

This study examined the effects of temperature on embryonic development, hatching success, and early larval survival in four estuarine crab species from the Pacific Northwest: the introduced European green crab, Carcinus maenas, and the native shore crabs Hemigrapsus nudus …