Physical Sciences and Mathematics Commons^™

Job Management Portal Software Review, Ruchir Elukurthy

University Honors Theses

This essay provides an overview of a computer science capstone project focused on developing a website for Abilities At Work, a non-profit organization. The website aims to assist employment specialists in managing clients' information and tracking their job application in finding meaningful employment. The essay highlights the various stages of the project, understanding requirements, selecting tools and technologies, creating an application architecture, and writing code. Also, this essay focuses on the challenges encountered during the project, along with the valuable lessons learned. This essay emphasizes how the project closely resembles real-world software development, offering insights for prospective students and professionals. …

A Deep Hierarchical Variational Autoencoder For World Models In Complex Reinforcement Learning Environments, Sriharshitha Ayyalasomayajula

Dissertations and Theses

Model-based reinforcement learning (MBRL) approaches leverage learned models of the environment to plan and make optimal decisions, reducing the need for extensive real-world interactions and enabling more efficient learning in complex domains such as robotics, autonomous systems, and resource allocation problems. They also provide interpretability and insight into the underlying dynamics, facilitating better decision-making and system understanding.

The world model is a model-based RL approach that employs generative neural network models to learn a compressed spatial and temporal representation of the environment. This work explores world models and a simple single-layered RNN model to learn a simple policy based on …

How Photorealistic Images Are Generated, Nahom Ketema

University Honors Theses

The field of computer graphics looks into how computers can be used to generate images. From using some trigonometry to plot 3D objects to using rays to calculate the lighting of an object, there are a variety of ways that we can use to draw objects onto a screen. For this thesis, we will be looking at a few of those methods to determine how photorealistic images are generated.

Epl Card Reader Capstone: The Strengths Of Partner Programming From A Team Leader's Perspective, Zach Yost

University Honors Theses

This essay looks to reflect back upon the successes and failures of the EPL Card Reader capstone project, sponsored by Edward Ivory, head of Portland State University's Electronics Prototyping Lab. The EPL Card Reader's goal is to provide a means of tracking and updating student activity and training on the various machines in the lab. Using a local computer port to host this web app a lab administrator or manager is able to scan a student's access badge to review which machines they have been trained on as well as update that training status. The app also has a running …

An Integrated Analysis Of Urban Sustainability In Portland: Issues, Indicators, Stakeholders, And Geospatial Assessment, Arun Kumar Pallathadka

Dissertations and Theses

This dissertation presents three individual studies that collectively explore the concept of urban sustainability. The research is grounded in the recognition that many cities worldwide are striving to achieve sustainable development, yet existing sustainability frameworks often lack comprehensive definition and consideration. Moreover, the existing sustainability frameworks and methods are often not clearly structured to allow for their replication and adaptation to meet the unique needs of diverse local settings. To address this gap, the dissertation utilizes the Social-Ecological-Technological Framework, with particular emphasis on equity, to investigate key issues in urban sustainability, such as indicators, stakeholder engagement, tradeoffs, and assessment. The …

Creating Regression Model For Non-Markov Transition Probability Using Pseudo-Observations, Michael Gray

Dissertations and Theses

A multi-state model is a graphical tool widely used to illustrate a transitional relationship between states in many applications. We will study the transition probabilities of an illness-death model, which is an example of a multi-state model. We will investigate transition probabilities using a counting process approach. Aalen-Johansen estimator is the gold-standard in estimating a transition probability. However, Aalen-Johansen estimator may be biased when the Markov assumption is violated. Therefore, Aalen-Johansen estimator is an unreliable estimator when the Markov assumption is violated. Several papers have published non-parametric estimators that accommodate for non-Markov models using a counting process approach.

Furthermore, there …

Survival Times And Investment Analysis With Dynamic Learning, Zhenzhen Li

Dissertations and Theses

The central statistical problem of survival analysis is to determine and characterize the conditional distribution of a survival time given a history of some observed health markers.

This dissertation contributes to the modeling of such conditional distributions in a setup where the health markers evolve randomly over time in a manner that can be represented by an Ito stochastic process, that is, a stochastic process that can be written as a sum of a time integral of some stochastic process and an Ito integral of some stochastic process, with both integrands subject to certain restrictions.

The random survival time is …

Uhv-Shear-Force Acoustic Near-Field Microscopy And Its Implementation In The Study Of Confined Mesoscopic Fluids, Theodore Alex Brockman

Dissertations and Theses

The design, construction, and implementation of Shear-force Acoustic Near-Field Microscopy (SANM), operational from ultrahigh vacuum (UHV) to ambient conditions--offering a pristine environment for more reliable characterization the hydrophobic/hydrophilic wetting properties of surfaces--is presented. SANM capitalizes on its sensitivity to the evanescent near-field acoustic emissions from a mesoscopic fluid (confined between the apex of a laterally oscillating tapered nanosized probe and a flat substrate) when subjected to shear motion. This distinct capability provides direct access to the fluid’s viscoelastic response when subjected to shear interactions, in contrast to indirect measurements performed by other standard probe proximity scanning techniques. The entire …

Pfas In News Media: A Quantitative And Qualitative Analysis, Madison Haley

University Honors Theses

News media analysis allows for a greater understanding of mainstream public concerns throughout time. The history of US news articles covering per- and polyfluoroalkyl substances (PFAS), a class of chemicals posing increasing threats to public health and the environment, demonstrates Americans' awareness and perceptions of these chemicals over time. Based on the quantitative and qualitative analyses of PFAS-related national news articles in 2012-2022, this study discusses media representations and public perceptions of PFAS during the stated period. Results indicate an over 5700% increase in PFAS-related news articles over the 10-year timespan. Further, thematic analysis reveals that PFAS-related news articles are …

The Role Of The Armed Forces Of The Philippines (Afp) In Disaster Response And Adaptation Strategies To Climatic Disasters In Manila, Edmundo Nicolas Jr.

Geography Masters Research Papers

This study described the roles of the Armed Forces of the Philippines (AFP) in Disaster Risk Reduction Management (DRRM) in Metro Manila and how climate-induced hazards impact the role of the military. It used a qualitative approach, which involved semi- structured interviews among AFP officers and barangay leaders with expertise and experience in DRRM and an analysis of selected policy documents and military doctrine. These methods revealed that: (1) the military acts as a political first-aid, since they are the first responders – thus, the face of the local government – in climactic disasters during peacetime; (2) the military is …

Flash-Rt: Using High-Dose Radiation For Clinical Radiation Therapy, Deja Stubbs

University Honors Theses

This paper is a literature review on the possible mechanisms behind the FLASH effect and why such research can advance the world of radiology treatment by modifying current clinical linear accelerators to produce ultra-high doses of radiation. Radiation Therapy, also known as external Beam Radiation Therapy, is a common type of cancer treatment. Globally, cancer is the second-leading cause of death, but has seen an increase in survival rates over the past couple of years. Cancer can develop in almost any part of the body since cancer is defined as uncontrolled cell growth. The FLASH Effect is seen when treating …

Indigenous Water Justice: Theory, Gaps, And Opportunities For Application, Ruby Howard

University Honors Theses

Indigenous people are particularly at risk of water scarcity in the U.S. and abroad, and face high rates of nonexistent or failing water infrastructure, water pollution, pipeline proposals that threaten water resources, and water-related climate change impacts. They also are often unequipped, politically and economically, to react and adapt to these impacts, resulting in devastating health impacts. Due to this widespread insecurity, many scholars are calling for the application of a theory and set of principles known as water justice. However, Indigenous people have pointed out that water justice literature does not focus enough on Indigenous issues, often neglecting the …

Stability Of Retinol In Liposomes As Measured By Fluorescence Lifetime Spectroscopy And Flim, Louis Sumrall, L. Smith, Elmukhtar Ehmed Alhatmi, Yekaterina G. Chmykh, D. Mitchell, Jay Nadeau

Physics Faculty Publications and Presentations

Retinol shows complex photophysical properties that make it potentially useful as an exogenous or endogenous probe of membrane microenvironment, but it has not been fully explored. In this study, we use bulk fluorescence lifetime measurements and fluorescence lifetime imaging microscopy (FLIM) to examine the stability of retinol in phosphatidylcholine (PC) multilamellar and unilamellar vesicles with and without cholesterol. We find that both light and exposure to ambient temperature and oxygen contribute to retinol degradation, with the addition of an antioxidant such as butylated hydroxytoluene (BHT) essential to provide stability, especially in the absence of cholesterol. With exposure to ultraviolet light …

What Is The Mathematics In Mathematics Education?, Eva Thanheiser

Mathematics and Statistics Faculty Publications and Presentations

In this paper I tackle the question What is the mathematics in mathematics education? By providing three different frames for the word mathematics.

1.

Frame 1: Mathematics as an abstract body of knowledge/ideas, the organization of that into systems and structures, and a set of methods for reaching conclusions.

2.

Frame 2: Mathematics as contextual, ever present, as a lens or language to make sense of the world.

3.

Frame 3: Mathematics as a verb (not a noun), a human activity, part of one’s identity.

After introducing the frames and examining their distinction and their overlap, I discuss their implication …

End-To-End Gpu Acceleration Of Low-Order-Refined Preconditioning For High-Order Finite Element Discretizations, Will Pazner, Tzanio Kolev, Jean-Sylvain Camier

Mathematics and Statistics Faculty Publications and Presentations

In this article, we present algorithms and implementations for the end-to-end GPU acceleration of matrix-free low-order-refined preconditioning of high-order finite element problems. The methods described here allow for the construction of effective preconditioners for high-order problems with optimal memory usage and computational complexity. The preconditioners are based on the construction of a spectrally equivalent low-order discretization on a refined mesh, which is then amenable to, for example, algebraic multigrid preconditioning. The constants of equivalence are independent of mesh size and polynomial degree. For vector finite element problems in H(curl) and H(div) (e.g., for electromagnetic or radiation diffusion problems), …

Willow Abundance And Condition Mapping In Rocky Mountain National Park, Eric M. Nielsen

Institute for Natural Resources Publications

Riparian and wetland willow species have undergone serious declines in Rocky Mountain National Park as a consequence of a variety of environmental changes and, most recently, damage resulting from moose overpopulation. To address concerns about the long-term status of willows in the park, we developed remote sensing-based raster maps of riparian and wetland willow species presence, canopy cover percentage, canopy height, and leaf area index. All outputs were produced at 3-meter resolution, and represent willows as they existed in 2021. The mapping was performed via random forests classification and regression models trained on several hundred vegetation plots from a variety …

Developing A Sample-Efficient Analytical Pathway For A Qualitative Chemical Investigation Of Ancestral Chilkat Dyeing And Weaving Practices, Dario Gerlando Durastanti

Dissertations and Theses

The project goal is to identify the dyestuffs used in hand-woven Chilkat blankets from the collection of the Alaska State Museum and the Sheldon Jackson Museum. Chilkat weaving is practiced by Northwest coastal clans, particularly in Southeast Alaska since at least the early 19th century. Through this collaboration, 117 wool fibers from 23 Chilkat textiles, and 193 reference samples consisting of dyed fibers using both natural and synthetic dye sources, raw dye material, and dye bath aliquots were provided to the lab for reference characterization and identification. In these analyses, dyes were classified as being either natural or synthetic, subdivided …

Implementing A Functional Logic Programming Language Via The Fair Scheme, Andrew Michael Jost

Dissertations and Theses

This document presents a new compiler for the Functional Logic programming language Curry based on a novel pull-tabbing evaluation strategy called the Fair Scheme. A simple version of the Fair Scheme is proven sound, complete, and optimal. An elaborated version is also developed, which supports narrowing computations and other features of Curry, such as constraint programming, equational constraints, and set functions.

The Fair Scheme is used to develop a new Curry system called Sprite, a high-quality, performant implementation whose aims are to promote practical uses of Curry and to serve as a laboratory for further research. An important aspect of …

A Gridded Co2 Emissions Inventory For Portland, Or, James E. Powell

Dissertations and Theses

Here we develop a new high resolution inventory of CO₂ emissions for the three Oregon counties which comprise the bulk of the City of Portland, Oregon, USA. Locally curated and long-running data collection efforts for on-road traffic activity and emission rates are used to model on-road emissions, and a new survey of the area's natural gas network informs the building energy model. The inventory estimates total emissions of CO₂ for each hour of the year 2018 in the on-road, residential, and commercial building sectors at 1 km² resolution. The onroad inventory compares to within 3% with an …

Phytoplankton Community As An Indicator Of Cyanobacteria Harmful Algal Blooms In High Mountain Lakes, Victoria Elizabeth Avalos

Dissertations and Theses

Cyanobacteria blooms are a growing issue worldwide and can be harmful to both aquatic life and human health. Warm temperatures, nutrient loading, stable water columns, and selective grazing of zooplankton and phytoplankton can contribute to cyanobacteria bloom formation. In this study, I characterized the algal communities and water quality differences in two physiographically similar lakes with relatively little human influences, Odell and Crescent Lakes, Oregon, to better understand potential contributing factors to cyanobacteria harmful algal bloom formation (cyanobacteria bloom) in Odell Lake.

There are three hypotheses in this study:

1. If there was a cyanobacteria bloom in Odell Lake, but not …

Glacialwater: A Dynamic Microbial Medium, Gilda Varliero, Pedro H. Lebre, Andrew G. Fountain, Beat Frey, Alexandre M. Anesio, Don A. Cowan

Geology Faculty Publications and Presentations

Microbial communities and nutrient dynamics in glaciers and ice sheets continuously change as the hydrological conditions within and on the ice change. Glaciers and ice sheets can be considered bioreactors as microbiomes transform nutrients that enter these icy systems and alter the meltwater chemistry. Global warming is increasing meltwater discharge, affecting nutrient and cell export, and altering proglacial systems. In this review, we integrate the current understanding of glacial hydrology, microbial activity, and nutrient and carbon dynamics to highlight their interdependence and variability on daily and seasonal time scales, as well as their impact on proglacial environments.

Caspi: Collaborative Photon Processing For Active Single-Photon Imaging, Jongho Lee, Atul Ingle, Jenu V. Chacko, Kevin W. Eliceiri, Mohit Gupta

Computer Science Faculty Publications and Presentations

Image sensors capable of capturing individual photons have made tremendous progress in recent years. However, this technology faces a major limitation. Because they capture scene information at the individual photon level, the raw data is sparse and noisy. Here we propose CASPI: Collaborative Photon Processing for Active Single-Photon Imaging, a technology-agnostic, application-agnostic, and training-free photon processing pipeline for emerging high-resolution single-photon cameras. By collaboratively exploiting both local and non-local correlations in the spatio-temporal photon data cubes, CASPI estimates scene properties reliably even under very challenging lighting conditions. We demonstrate the versatility of CASPI with two applications: LiDAR imaging over a …

Evapotranspiration Of Residential Lawns Across The United States, Noortje H. Grijseels, Elizaveta Litvak, Meghan Avolio, Anika R. Bratt, Jeannine Cavender-Bares, Peter M. Groffman, Sarah E. Hobbie, Susannah B. Lerman, Jennifer L. Morse, Multiple Additional Authors

Environmental Science and Management Faculty Publications and Presentations

Despite interest in the contribution of evapotranspiration (ET) of residential turfgrass lawns to household and municipal water budgets across the United States, the spatial and temporal variability of residential lawn ET across large scales is highly uncertain. We measured instantaneous ET (ET_inst) of lawns in 79 residential yards in six metropolitan areas: Baltimore, Boston, Miami, Minneapolis-St. Paul (mesic climates), Los Angeles and Phoenix (arid climates). Each yard had one of four landscape types and management practices: traditional lawn-dominated yards with high or low fertilizer input, yards with water-conserving features, and yards with wildlife-friendly features. We measured ET_{inst …}

Divergence-Conforming Velocity And Vorticity Approximations For Incompressible Fluids Obtained With Minimal Facet Coupling, Jay Gopalakrishnan, Lukas Kogler, Philip L. Lederer, Joachim Schöberl

Mathematics and Statistics Faculty Publications and Presentations

We introduce two new lowest order methods, a mixed method, and a hybrid discontinuous Galerkin method, for the approximation of incompressible flows. Both methods use divergence-conforming linear Brezzi–Douglas–Marini space for approximating the velocity and the lowest order Raviart–Thomas space for approximating the vorticity. Our methods are based on the physically correct viscous stress tensor of the fluid, involving the symmetric gradient of velocity (rather than the gradient), provide exactly divergence-free discrete velocity solutions, and optimal error estimates that are also pressure robust. We explain how the methods are constructed using the minimal number of coupling degrees of freedom per facet. …

Quantum Multi-Solution Bernoulli Search With Applications To Bitcoin’S Post-Quantum Security, Alexandru Cojocaru, Juan Garay, Fang Song, Petros Wallden

Computer Science Faculty Publications and Presentations

A proof of work (PoW) is an important cryptographic construct which enables a party to convince other parties that they have invested some effort in solving a computational task. Arguably, its main impact has been in the setting of cryptocurrencies such as Bitcoin and its underlying blockchain protocol, which have received significant attention in recent years due to its potential for various applications as well as for solving fundamental distributed computing questions in novel threat models. PoWs enable the linking of blocks in the blockchain data structure, and thus the problem of interest is the feasibility of obtaining a sequence …

Impacts Of Floodplain Restoration On Water Temperature And Macroinvertebrates In Whychus Creek, Oregon, Wesley Nathan Noone

Dissertations and Theses

Stream restoration is a proposed climate adaptation tool, however, outcomes of floodplain restoration on stream temperature have been debated. Despite a growing number of studies that investigated water temperature in restored streams, few have quantified thermal heterogeneity in new habitat types created by restored hydrogeomorphic processes and the impact of thermal diversity on the aquatic macroinvertebrate community. In this study, I evaluated three hypotheses: 1) restoration increases habitat diversity, 2) habitat diversity increases water temperature heterogeneity, and 3) restored reaches have more diverse macroinvertebrate communities. I collected a total of 40 macroinvertebrate samples and characterized environmental conditions in three reaches …

Ce-Qual-W2 Performance Assessment Modeling 1979 Grh Flume Study, Logan Negherbon

Civil and Environmental Engineering Master's Project Reports

In an early review of numerical reservoir hydrodynamic models, the US Army Corps of Engineers developed a physical model at the US Army Waterways Experiment Station to assess the performance of modeling cold water underflow with numerous 2-dimensional and 3-dimensional numerical hydrodynamic models. Within this effort, the precursor for CE-QUAL-W2, the Laterally Averaged Reservoir Model, was defined and applied with limited success in representing the vertical velocity profile and outflow temperatures series collected from the physical model in the General Reservoir Hydrodynamics flume. CE-QUAL-W2 has since been modified from this early form in numerous ways including incorporation of higher order …

Longitudinal Changes In Alzheimer’S-Related Plasma Biomarkers And Brain Amyloid, Murat Bilgel, Abhay Moghekar, Henrik Zetterberg, Bruno Jedynak, Multiple Additional Authors

Mathematics and Statistics Faculty Publications and Presentations

Introduction Understanding longitudinal plasma biomarker trajectories relative to brain amyloid changes can help devise Alzheimer’s progression assessment strategies.

Methods We examined the temporal order of changes in plasma amyloid-β ratio (Aβ42/Aβ40), glial fibrillary acidic protein (GFAP), neurofilament light chain (NfL), and phosphorylated tau ratios (p-tau181/Aβ42, p-tau231/Aβ42) relative to 11C-Pittsburgh compound B (PiB) positron emission tomography (PET) cortical amyloid burden (PiB−/+). Participants (n = 199) were cognitively normal at index visit with a median 6.1-year follow-up.

Results PiB groups exhibited different rates of longitudinal change in Aβ42/Aβ40 (β = 5.41 × 10-4, SE = 1.95 × 10-4, p = 0.0073). …

Cyclic Behavior Of Transitional Fine-Grained Soils In Northern Willamette Valley, Frank Jarman

Civil and Environmental Engineering Master's Project Reports

As discussed within studies from Idriss and Boulanger (2008) and Bray and Sancio (2006), the undrained cyclic shear behavior of low-plasticity fine-grained soils will transition between liquefaction (sand-like behavior) to cyclic softening (clay-like behavior) over a narrow range of plasticity index (PI). Despite not being sufficiently understood, the cyclic behavior of low plasticity silts has become an increasingly important field of study due to the significant impact it has on ground deformations and infrastructure failure in areas that are seismically active. Laboratory tests were performed on soils by third party consultants on a site located in the northern Willamette Valley, …

Management Plan For The Western Painted Turtle At The Sandy River Delta In Troutdale, Oregon, Emma Scott

Environmental Science and Management Professional Master's Project Reports

This management plan has been prepared for the Lower Columbia Estuary Partnership and is intended to provide guidance for the improvement and protection of western painted turtle (Chrysemys picta bellii) habitat at the Sandy River Delta in Troutdale, Oregon. The Sandy River Delta is a 1500-acre natural area situated where the Columbia and Sandy Rivers meet. Its dynamic floodplain habitat supports a diverse assemblage of species, including the western painted turtle, an Oregon Conservation Strategy Species. A small, unknown number of western painted turtles utilize the wetland habitats of the Sandy River Delta, and the frequency in observations …