Digital Commons Network^™

Multi-Method Investigation Of Factors Influencing Amyloid Onset And Impairment In Three Cohorts, Tobey J. Betthauser, Murat Bilgel, Rebecca L. Koscik, Bruno Jedynak, Yang An, Kristina A. Kellett, Abhay Moghekar, Erin M. Jonaitis, Charles K. Stone, Multiple Additional Authors

Mathematics and Statistics Faculty Publications and Presentations

Alzheimer’s disease biomarkers are becoming increasingly important for characterizing the longitudinal course of disease, predicting the timing of clinical and cognitive symptoms, and for recruitment and treatment monitoring in clinical trials. In this work, we develop and evaluate three methods for modelling the longitudinal course of amyloid accumulation in three cohorts using amyloid PET imaging. We then use these novel approaches to investigate factors that influence the timing of amyloid onset and the timing from amyloid onset to impairment onset in the Alzheimer’s disease continuum.

Data were acquired from the Alzheimer’s Disease Neuroimaging Initiative (ADNI), the Baltimore Longitudinal Study of …

Automatically Generating Scenarios From A Text Corpus: A Case Study On Electric Vehicles, Christopher W.H. Davis, Antoine J. Jetter, Philippe J. Giabbanelli

Engineering and Technology Management Faculty Publications and Presentations

Creating ‘what-if’ scenarios to estimate possible futures is a key component of decision-making processes. However, this activity is labor intensive as it is primarily done manually by subject-matter experts who start by identifying relevant themes and their interconnections to build models, and then craft diverse and meaningful stories as scenarios to run on these models. Previous works have shown that text mining could automate the model-building aspect, for example, by using topic modeling to extract themes from a large corpus and employing variations of association rule mining to connect them in quantitative ways. In this paper, we propose to further …

A Heuristic For The Two-Echelon Multi-Period Multi-Product Location–Inventory Problem With Partial Facility Closing And Reopening, Puntipa Punyim, Ampol Karoonsoontawong, Avinash Unnikrishnan, Vatanavongs Ratanavaraha

Civil and Environmental Engineering Faculty Publications and Presentations

In this paper, the two-echelon multi-period multi-product location–inventory problem with partial facility closing and reopening is studied. For each product and period, plants serve warehouses, which serve consolidation hubs, which service customers with independent, normally distributed demands. The schedule of construction, temporary partial closing, and reopening of modular capacities of facilities, the continuous-review inventory control policies at warehouses, the allocation of customer demands to hubs, and the allocation of hubs to warehouses are determined. The service levels for stockout at warehouses during lead time and the violation of warehouse and hub capacities are explicitly considered. The proposed mixed-integer non-linear program …

An Economical And Repeatable Method For Mapping Shade Cast On Water Channels, Eric M. Nielsen

Institute for Natural Resources Publications

The motivation of this work is to provide insights toward determining a viable strategy for statewide monitoring of riparian vegetation condition, with particular focus on developing a repeatable, costeffective method for assessment of progress toward achieving temperature-based water quality standards mandated by the federal Clean Water Act. A reliable monitoring strategy could in turn support a datadriven prioritization and assessment framework to increase the efficiency, effectiveness and accountability of riparian restoration efforts. In this project we developed and tested a method for mapping shade cast on water channels by riparian vegetation using optical imagery sources that are affordable and regularly …

An Integral Transform For Quantum Amplitudes, Jack C. Straton

Physics Faculty Publications and Presentations

The central impediment to reducing multidimensional integrals of transition amplitudes to analytic form, or at least to a fewer number of integral dimensions, is the presence of magnitudes of coordinate vector differences (square roots of polynomials) |x1−x2|2=x21−2x1x2cosθ+x2 √ in disjoint products of functions. Fourier transforms circumvent this by introducing a three-dimensional momentum integral for each of those products, followed in many cases by another set of integral transforms to move all of the resulting denominators into a single quadratic form in one denominator whose square my be completed. Gaussian transforms introduce a one-dimensional integral for each such product while squaring …

Equilibria: Sustainability And Eco-Awareness In Music Production, Ashley A. Kahl-Placek

University Honors Theses

Cross-disciplinary exploration between science and the arts is one tool to help solve some of the biggest issues facing humans. Climate change and loss of biodiversity can be represented via sound art and contemporary music composition. Wholistic eco-awareness and sustainability are possible when projects are based in unique species-inspired soundscapes, the cultivation of targeted, action-inspiring lyricism, and a sustainable navigation of the marketing and distribution pathways of the music industry. From the fall of 2021 to summer of 2022, field recordings of unique ecosystems were collected and combined with songwriting rooted in a love and hope for the future of …

Quantum Algorithms For Attacking Hardness Assumptions In Classical And Post‐Quantum Cryptography, J.-F. Biasse, X. Bonnetain, E. Kirshanova, A. Schrottenloher, Fang Song

Computer Science Faculty Publications and Presentations

In this survey, the authors review the main quantum algorithms for solving the computational problems that serve as hardness assumptions for cryptosystem. To this end, the authors consider both the currently most widely used classically secure cryptosystems, and the most promising candidates for post-quantum secure cryptosystems. The authors provide details on the cost of the quantum algorithms presented in this survey. The authors furthermore discuss ongoing research directions that can impact quantum cryptanalysis in the future.

Planning And Real-Time Resource Allocation In Freight Logistics Systems Utilizing Emerging Transportation Technologies, Darshan Rajesh Chauhan

Dissertations and Theses

Transportation is a key driver of any national economy. In the United States, the transportation sector contributes $1.3 trillion to the economy, of which freight transportation represents more than 50%. Trucks alone account for more than 70% freight movements in the United States. In addition to worsening stress at ports of entry and traffic congestion in the system, freight also accounts for nearly one-third of the greenhouse gas emissions in the United States. Emerging transportation technologies like electric unmanned aerial vehicles (or drones) and electric vehicles can provide a more sustainable alternative to combat greenhouse gas emissions and reduce the …

Development Of A Configurable Real-Time Event Detection Framework For Power Systems Using Swarm Intelligence Optimization, Umar Farooq

Dissertations and Theses

Modern power systems characterized by complex topologies require accurate situational awareness to maintain an adequate level of reliability. Since they are large and spread over wide geographical areas, occurrence of failures is inevitable in power systems. Various generation and transmission disturbances give rise to a mismatch between generation and demand, which manifest as frequency events. These events can take the form of negligible frequency deviations or more severe emergencies that can precipitate cascading outages, depending on the severity of the disturbance and efficacy of remedial action schema. The impacts of such events have become more critical with recent decline in …

Arbuscular Mycorrhizal Fungi Colonization Response To Dike Removal In The Salmon River Estuary, Elinore Webb

Dissertations and Theses

Arbuscular mycorrhizal fungi (AMF) form symbiotic relationships with wetland plants and are important to the restoration of coastal estuaries. The purpose of this study was to assess the presence and colonization of arbuscular mycorrhizal fungi in Distichlis spicata from three formerly diked areas of the Salmon River Estuary to determine an initial understanding of the mycorrhizal community in tidal wetlands post-restoration. AMF were present in all four sample areas and total colonization ranged on average 39-72%. The reference site had the lowest levels of total colonization, which is contrary to the findings of studies of younger wetland restorations. Most importantly, …

Orthotrichum Lyellii As An Active Moss Biomonitor: Examining The Interplay Between Ambient Pm10, Bulk Deposition And Heavy Metals In An Urban Environment, Scott Bradley Kiel

Dissertations and Theses

The importance of monitoring and preventing pollution in the environment is a globally recognized issue. Of the criteria pollutants outlined by the United States Environmental Protection Agency, particulate matter is among these least understood in relation to toxicity and most wide-spread. Many governments have employed continuous air quality monitoring networks to track ambient levels of particulate matter, but are often too widespread to capture the heterogeneity of the urban environment, especially for heavy metal deposition. In Portland, OR, the epiphytic moss Orthotrichum lyellii was successfully used as a low-cost passive biomonitor to increase the spatial resolution of pollution around the …

The Process Of Establishing A Blooming Chemistry Tool For Use In Undergraduate Chemistry Education And Research, Emryse Geye

Dissertations and Theses

While it is still common in college chemistry to assess student learning and skill with summative assessments, the CER community does not currently have a simple tool to determine and communicate whether an assessment is actually aligned with the outcomes of interest. In particular, as so-called evidence-based teaching practices and active learning strategies gain a foothold in college chemistry classrooms, the ability to communicate whether those (often labor-, cost-, and time-intensive) interventions are not only aligned with course outcomes, but also provide measurable benefit to students becomes more imperative. While college chemistry has made some strides in the area of …

Modeling And Analysing The Impact Of Heat Pump Water Heaters On Distribution Systems Using Gridlab-D, Midrar Adham

Dissertations and Theses

With the constant increase in energy demand, finding ways to reduce peak load and the energy-costs factors has become more imperative. Domestic water heating showcases a significant opportunity for such applications. Water heating is the second-highest energy consumer in the residential sector across the United States. Electric Water Heaters (EWHs), in particular, constitute nearly 43% of American household water heating energy consumption. Heat Pump Water Heater (HPWH), on the other hand, is an advanced water heating technology that has recently emerged in the United States residential market.

The objectives of this work are to develop a HPWH model and build …

Drivers Of Spatiotemporal Eukaryote Plankton Distribution In A Trans-Basin Water Transfer Canal In China, Yuying Li, Faisal Hayat Khan, Jiamin Wu, Yun Zhang, Yeqing Jiang, Xiaonuo Chen, Yinlei Yao, Yangdong Pan, Xuemei Han

Environmental Science and Management Faculty Publications and Presentations

Planktonic eukaryotes are important components of aquatic ecosystems, and analyses of the whole eukaryotic planktonic community composition and function have far-reaching significance for water resource management. We aimed to understand the spatiotemporal variation and drivers of eukaryotic plankton distribution in the Middle Route Project of the South-to-North Water Diversion in Henan Province, China. Specifically, we examined planktonic assemblages and water quality at five stations along the canal and another one located before the dam in March, June, September, and December 2019. High-throughput sequencing revealed that the eukaryotic plankton community was primarily composed of 53 phyla, 200 genera, and 277 species, …

Nmr Analyses Of Flavored E-Cigarette Liquids Before And After Aerosolization, Paul Joseph Kerber

Dissertations and Theses

Electronic cigarettes (e-cigarettes) are the most commonly used tobacco products among adolescents with ~11 and ~3% of high school and middle school students reporting past 30 day use in 2021 according to the Centers for Disease Control and Prevention (CDC), respectively. Furthermore, greater than ~80% of high school and middle school e-cigarette consumers use flavored e-liquids. Consumers can be exposed to variable toxicant levels upon e-liquid aerosolization, depending on the composition of the e-liquid, type of e-cigarette, e-cigarette settings, and other customizations.

E-liquids are typically composed of a carrier solvent (propylene glycol (PG) and glycerol (GL)), flavorants, and nicotine. PG …

Summing Hecke Eigenvalues Over Polynomials, Liubomir Chiriac, Liyang Yang

Mathematics and Statistics Faculty Publications and Presentations

In this paper we estimate sums of the form ∑n≤X|aSymmπ(|f(n)|)|, for symmetric power lifts of automorphic representations π attached to holomorphic forms and polynomials f(x)∈Z[x] of arbitrary degree. We give new upper bounds for these sums under certain natural assumptions on f. Our results are unconditional when deg(f)≤4. Moreover, we study the analogous sum over polynomials in several variables. We obtain an estimate for all cubic polynomials in two variables that define elliptic curves.

Modeling Postfire Effects On Snow Albedo And Forest Recovery Over A Chronosequence Of Burned Forests In The Triple Divide Region Of The Rocky Mountains, Anton J. Surunis

Dissertations and Theses

Wildfires impact snow albedo, forest cover, and forest structure and thus snow melt rate and snowpack supply for as long as 15 years following burn. These effects have not been quantified at fine spatial resolutions and long time periods at a watershed scale. I modeled the effects of postfire effects on snow albedo, snow-mass energy balance, and resulting snow-water equivalent (SWE) depth over a long-time scale and at a fine spatial resolution. Using a spatially and temporally distributed snow evolution model called SnowModel, I modeled postfire effects on snow albedo and forest structure over postfire recovery within 8 forest fires …

Development Of A Configurable Derms Test System In Gridapps-D, Sean James Keene

Dissertations and Theses

Distributed Energy Resources and their increased penetration within the power grid are a suitable method to provide essential reliability services. In order to do so, they must operate in aggregate. Aggregation of a wide variety of systems with varying standards and protocols is a complex task, which could benefit from rules and standards to support interoperability. To this end, the Portland State University Power Lab has developed the Energy Grid of Things project, which includes a Distributed Energy Resource Management System to provide aggregation and demonstrate the usage of an Energy Services Interface: a set of rules governing the interface …

Learning From Machines: Insights In Forest Transpiration Using Machine Learning Methods, Morgan Thornwell

Dissertations and Theses

Machine learning has been used as a tool to model transpiration for individual sites, but few models are capable of generalizing to new locations without calibration to site data. Using the global SAPFLUXNET database, 95 tree sap flow data sites were grouped using three clustering strategies: by biome, by tree functional type, and through use of a k-means unsupervised clustering algorithm. Two supervised machine learning algorithms, a random forest algorithm and a neural network algorithm, were used to build machine learning models that predicted transpiration for each cluster. The performance and feature importance in each model were analyzed and compared …

Analyzing Classroom Discourse To Investigate Structuring Equitable Mathematical Talk In Small Groups And Whole-Class Discussions, Brittney Marie Ellis

Dissertations and Theses

Shifting classroom discourse to be more student-centered has become an integral part of reform-oriented instructional practices. At the same time, shifting discourse can open up opportunities for inequity to occur in the immediate learning environment as both the quantity and quality of mathematical talk changes. In this project, I examined complexities involved in such settings by using discourse analysis methods to explore the positioning of students relative to mathematics content and each other's mathematical ideas. First, I analyzed the ways teachers' discourse during group work enactments related to established equitable teaching practices. Findings from this study suggest communicating group tasks …

The Impact Of Human Activity On Coastal Zones With Elise Granek, Elise F. Granek

PDXPLORES Podcast

In this episode of PDXPLORES, Professor Elise Granek discusses the coastal zone- transition zones between land, sea, and atmosphere. These ecosystems provide vital ecological, cultural, and commercial benefits. Around the world, they are home to a vast number of species, support critical industries, and sustain the cultural heritage of the people who have called them home. As with all ecosystems, they are vulnerable. Given the intense human dependence on the continued viability of these coastal ecosystems, understanding the impact of human activity on the species that inhabit them is essential to identifying solutions to address the suite of impacts. What …

Toward Analyzing The Diversity Of Extractive Summaries, Aaron David Hudson

Dissertations and Theses

As the amount of text generated across the internet continues to increase, developing methods for processing that text to glean valuable insights is paramount. Automatic text summarization is one such method that aims to provide a concise and representative summary of input text, allowing users access to the most salient points from a large amount of textual data. However, in working with these summaries, especially those generated from social media data, questions arise about not only the quality of a summary, but also its ability to reflect the diversity of user perspectives. This work examines the quality of summaries with …

Gender Equity And State-Mosque Relations In Middle East North Africa: A Case Study Of Tunisia, Joy Amarachi Agbugba

Dissertations and Theses

Why is the Middle East North Africa region consistently ranked the lowest on the gender equity scale? This question is quite perplexing and that has driven several scholarly researchers to investigate the situation of gender and women's rights within the states in the region. In this research, I explore the various theories explaining the cause of gender inequity in this region including the Islam thesis/social modernization theory, political-economic theory, and psychological/social structural theories, with an emphasis on the Islamic thesis theory. I argue that the state's support and prioritization of Muslim/sharia law over federal law is a major contributor to …

Unpaired Style Transfer Conditional Generative Adversarial Network For Scanned Document Generation, David Jonathan Hawbaker

Dissertations and Theses

Neural networks are a powerful machine learning tool, especially when trained on a large dataset of relevant high-quality data. Generative adversarial networks, image super resolution and most other image manipulation neural networks require a dataset of images and matching target images for training. Collecting and compiling that data can be time consuming and expensive. This work explores an approach for building a dataset of paired document images with a matching scanned version of each document without physical printers or scanners. A dataset of these document image pairs could be used to train a generative adversarial network or image super resolution …

Using An Affinity Analysis To Identify Phytoplankton Associations, Weiju Zhu, Zhaojian Ding, Yangdong Pan, Quanxi Wang

Environmental Science and Management Faculty Publications and Presentations

Phytoplankton functional traits can represent particular environmental conditions in complex aquatic ecosystems. Categorizing phytoplankton species into functional groups is challenging and time-consuming, and requires high-level expertise in species autecology. In this study, we introduced an affinity analysis to aid the identification of candidate associations of phytoplankton from two data sets comprised of phytoplankton and environmental information. In the Huaihe River Basin with a drainage area of 270,000 km2 in China, samples were collected from 217 selected sites during the low-water period in May 2013; monthly samples were collected during 2006–2011 in a man-made pond, Dishui Lake. Our results indicated that …

The Efficacy Of Research-Based "Mathematics For All" Professional, Kathleen Melhuish, Eva P. Thanheiser, Alexander White, Brenda Rosencrans, J. Michael Shaughnessy, Linda Foreman, Andrew Riffel, Layla Guyot

Mathematics and Statistics Faculty Publications and Presentations

This article contributes to the larger narrative around what makes a mathematics professional development (PD) successful and in what ways. We share a research-based PD model that was implemented in elementary schools in an urban school district for 3 years. The model uses a pseudo lesson study approach and emphasizes standards-based instruction. We found that teachers made gains in knowledge and instruction quality. However, whereas some students saw gains on standardized assessments, this was the case only for students who were not members of historically minoritized groups (Black/Latino), countering our assumptions that the PD would lead to equitable achievement results. …

Reimagine Fire Science For The Anthropocene, Jacquelyn K. Shuman, Jennifer K. Balch, Rebecca T. Barnes, Philip E. Higuera, Andres Holz, Multiple Additional Authors

Geography Faculty Publications and Presentations

Fire is an integral component of ecosystems globally and a tool that humans have harnessed for millennia. Altered fire regimes are a fundamental cause and consequence of global change, impacting people and the biophysical systems on which they depend. As part of the newly emerging Anthropocene, marked by human-caused climate change and radical changes to ecosystems, fire danger is increasing, and fires are having increasingly devastating impacts on human health, infrastructure, and ecosystem services. Increasing fire danger is a vexing problem that requires deep transdisciplinary, trans-sector, and inclusive partnerships to address. Here, we outline barriers and opportunities in the next …

Efficiency In The Upper Deschutes Basin: Understanding The Hydrosocial Implications Of Irrigation Canal Piping, Rebecca Anderson

Dissertations and Theses

In response to water scarcity, irrigation efficiency projects aim to conserve water for in-stream flow and agricultural use. Piping irrigation canals is a common irrigation efficiency method which reduces the loss of incidental recharge, resulting in trade-offs within a hydrosocial system. Few studies have focused on the consequences of canal piping and none have integrated a critical analysis of the social factors involved in deciding what constitutes 'efficient' water use. This study seeks to fill this gap by combining natural and social science to give attention to the scales and perspectives involved in irrigation efficiency canal piping and the material …

Improved Photodecarboxylation Properties In Zinc Photocages Constructed Using M‐Nitrophenylacetic Acid Variants, Austin K. Shigemoto, Avik Bhattacharjee, Erin E. Hickey, Hallee Jade Boyd, Theresa M. Mccormick, Shawn C. Burdette

Chemistry Faculty Publications and Presentations

The methoxy- and fluoro-derivatives of meta-nitrophenylacetic acid (mNPA) chromophores undergo photodecarboxylation with comparable quantum yields to unsubstituted mNPA, but uncage at red-shifted excitation wavelengths. This observation prompted us to investigate DPAdeCageOMe (2-[bis(pyridin-2-ylmethyl)amino]-2-(4-methoxy-3-nitrophenyl)acetic acid) and DPAdeCageF (2-[bis(pyridin-2-ylmethyl)amino]-2-(4-fluoro-3-nitrophenyl)acetic acid) as Zn2+ photocages. DPAdeCageOMe has a high quantum yield and exhibits other photophysical properties comparable to XDPAdeCage ({bis[(2-pyridyl)methyl]amino}(9-oxo-2-xanthenyl) acetic acid), the best perforiming Zn2+ photocage reported to date. Since the synthesis of DPAdeCageOMe is more straightforward than XDPACage, the new photocage will be a highly competitive tool for biological applications.

Snerf: Stylized Neural Implicit Representations For 3d Scenes, Thu Nguyen-Phuoc, Feng Liu, Lei Xiao

Computer Science Faculty Publications and Presentations

This paper presents a stylized novel view synthesis method. Applying state-of-the-art stylization methods to novel views frame by frame often causes jittering artifacts due to the lack of cross-view consistency. Therefore, this paper investigates 3D scene stylization that provides a strong inductive bias for consistent novel view synthesis. Specifically, we adopt the emerging neural radiance fields (NeRF) as our choice of 3D scene representation for their capability to render high-quality novel views for a variety of scenes. However, as rendering a novel view from a NeRF requires a large number of samples, training a stylized NeRF requires a large amount …