Physical Sciences and Mathematics Commons^™

Localized Eigenvectors On Metric Graphs, Hannah Kravitz, Moysey Brio, J G, Caputo

Mathematics and Statistics Faculty Publications and Presentations

We analyze the eigenvectors of the generalized Laplacian for two metric graphs occurring in practical applications. In accordance with random network theory, localization of an eigenvector is rare and the network should be tuned to observe exactly localized eigenvectors. We derive the resonance conditions to obtain localized eigenvectors for various geometric configurations and their combinations to form more complicated resonant structures. These localized eigenvectors suggest new indicators based on the energy density; in contrast to standard criteria, ours provide the number of active edges. We also suggest practical ways to design resonating systems based on metric graphs. Finally, …

Mmwave Rat Optimization: Mac Layer Initial Access Design And Transport Layer Integration, Suresh Srinivasan

Dissertations and Theses

MmWave Radio Access Technology (RAT) is a promising technology for wireless communication due its large bandwidth and is already being deployed in 5G cellular and emerging WiFi technologies. MmWave systems use highly directional beams with narrow beamwidths to overcome the high path loss associated with their frequency bands. A mmWave radio can be used either in a standalone mode (where all radios use the same technology) or simultaneously with other technologies such as LTE and low frequency WiFi in a communication mode commonly referred to as integrated mode. This thesis proposes two methods to optimize mmWave RAT performance in both …

Deep Structure Of Siletzia In The Puget Lowland: Imaging An Obducted Plateau And Accretionary Thrust Belt With Potential Fields, Megan L. Anderson, Richard J. Blakely, Ray E. Wells, Joe D. Dragovich

Geology Faculty Publications and Presentations

Detailed understanding of crustal components and tectonic history of forearcs is important due to their geological complexity and high seismic hazard. The principal component of the Cascadia forearc is Siletzia, a composite basaltic terrane of oceanic origin. Much is known about the lithology and age of the province. However, glacial sediments blanketing the Puget Lowland obscure its lateral extent and internal structure, hindering our ability to fully understand its tectonic history and its influence on modern deformation. In this study, we apply map-view interpretation and two-dimensional modeling of aeromagnetic and gravity data to the magnetically stratified Siletzia terrane revealing its …

Watershed, Lake, And Food Web Factors Influence Diazotrophic Cyanobacteria In Mountain Lakes, Lara Jansen, Daniel Sobota, Yangdong Pan, Angela Strecker

Environmental Science and Management Faculty Publications and Presentations

Cyanobacterial blooms can occur in freshwater ecosystems largely isolated from development and not experiencing extensive cultural eutrophication. For example, remote mountain lakes can experience intense blooms of diazotrophic (nitrogen-fixing) cyanobacteria caused by factors acting at different spatial and temporal scales. In this study, we examined how cross-scale interactions among watershed, lake, and food web characteristics influence diazotrophic cyanobacteria biovolume in mountain lakes. We quantified diazotrophic cyanobacteria biovolume, zooplankton abundance, and physico-chemical variables for 29 lakes in the Cascade Mountains of Oregon, USA, in summer 2019. Watershed characteristics were compiled from historical datasets available for the region. Diazotrophic cyanobacteria biovolume ranged …

Brief Communication: Recent Estimates Of Glacier Mass Loss For Western North America From Laser Altimetry, Brian Menounos, Caitlyn Forentine, Alex A. Gardner, Andrew G. Fountain

Geology Faculty Publications and Presentations

Glaciers in western North American outside of Alaska are often overlooked in global studies because their potential to contribute to changes in sea level is small. Nonetheless, these glaciers represent important sources of freshwater, especially during times of drought. Differencing recent ICESat-2 data from a digital elevation model derived from a combination of synthetic aperture radar data (TerraSAR-X/TanDEM-X), we find that over the period 2013–2020, glaciers in western North America lost mass at a rate of 12:3+3:5 Gt yr^-1. This rate is comparable to the rate of mass loss (11:71:0 Gt yr1) for the period 2018– 2022 calculated …

Integral Representations Over Finite Limits For Quantum Amplitudes, Jack C. Straton

Physics Faculty Publications and Presentations

We extend previous research to derive three additional M-1-dimensional integral representations over the interval [0,1]" The prior version covered the interval [0,∞]" role="presentation position: relative;">[0,∞][0,∞]. This extension applies to products of M Slater orbitals, since they (and wave functions derived from them) appear in quantum transition amplitudes. It enables the magnitudes of coordinate vector differences (square roots of polynomials) |x1−x2|=x12−2x1x2cosθ+_x22" to be shifted from disjoint products of functions into a single quadratic form, allowing for the completion of its square. The M-1-dimensional integral representations of M Slater orbitals that both this extension and the prior version introduce …

Self-Optimizing Feature Generation Via Categorical Hashing Representation And Hierarchical Reinforcement Crossing, Wangyang Ying, Dongjie Wang, Kunpeng Liu, Leilei Sun, Yanjie Fu

Computer Science Faculty Publications and Presentations

Feature generation aims to generate new and meaningful features to create a discriminative representation space. A generated feature is meaningful when the generated feature is from a feature pair with inherent feature interaction. In the real world, experienced data scientists can identify potentially useful feature-feature interactions, and generate meaningful dimensions from an exponentially large search space in an optimal crossing form over an optimal generation path. But, machines have limited human-like abilities. We generalize such learning tasks as self-optimizing feature generation. Self-optimizing feature generation imposes several under-addressed challenges on existing systems: meaningful, robust, and efficient generation. To tackle these challenges, …

Improved Subseasonal Prediction Of South Asian Monsoon Rainfall Using Data-Driven Forecasts Of Oscillatory Modes, Eviatar Bach, Venkat Krishnamurthy, Safa Mote, Jagadish Shukla, A. Surjalal Sharma, Eugenia Kalnay, Michael Ghil

Mathematics and Statistics Faculty Publications and Presentations

Predicting the temporal and spatial patterns of South Asian monsoon rainfall within a season is of critical importance due to its impact on agriculture, water availability, and flooding. The monsoon intraseasonal oscillation (MISO) is a robust northwardpropagating mode that determines the active and break phases of the monsoon and much of the regional distribution of rainfall. However, dynamical atmospheric forecast models predict this mode poorly. Data-driven methods for MISO prediction have shown more skill, but only predict the portion of the rainfall corresponding to MISO rather than the full rainfall signal. Here, we combine state-of-the-art ensemble precipitation forecasts from a …

The Fourier–Legendre Series Of Bessel Functions Of The First Kind And The Summed Series Involving 1F2 Hypergeometric Functions That Arise From Them, Jack C. Straton

Physics Faculty Publications and Presentations

The Bessel function of the first kind JN^(kx) is expanded in a Fourier–Legendre series, as is the modified Bessel function of the first kind IN^(kx). The purpose of these expansions in Legendre polynomials was not an attempt to rival established numerical methods for calculating Bessel functions but to provide a form for JN^(kx) useful for analytical work in the area of strong laser fields, where analytical integration over scattering angles is essential. Despite their primary purpose, one can easily truncate the series at 21 terms to provide 33-digit accuracy that matches the IEEE extended precision in …

Proof Of The Kresch-Tamvakis Conjecture, John Caughman, Taiyo S. Terada

Mathematics and Statistics Faculty Publications and Presentations

In this paper we resolve a conjecture of Kresch and Tamvakis.

Critical Conversations Of Engaging Withthe Amte Standards, Eva Thanheiser, Jennifer Bay-Williams, Richard Velasco, Liza Bondurant

Mathematics and Statistics Faculty Publications and Presentations

This article is based on an opening plenary session at the Association of Mathematics Teacher Educators (AMTE) 2024 conference in Orlando, Florida, USA. The authors, who delivered the plenary in a panel format, focus specifically on the AMTE standard indicator that addresses power and privilege. This article is the product of the five authors reflecting on their panel and discussing its contents—in the form of this manuscript—with an external Open Reviewer. The result is a “quintalog” of the five authors in critical conversation with each other about their own reflections on the ways in which mathematics teacher educators and the …

Accretion Of Warm Chondrules In Weakly Metamorphosed Ordinary Chondrites And Their Subsequent Reprocessing, Alexander M. Ruzicka, Richard C. Hugo, Jon M. Friedrich, Michael Tyler Ream

Geology Faculty Datasets

To better understand chondrite accretion and subsequent processes, the textures, crystallography, deformation, and compositions of some chondrite constituents in ten lithologies of different cluster texture strength were studied in seven weakly metamorphosed (Type 3) and variably shocked ordinary chondrites (Ragland—LL3 S1, Tieschitz—H/L3 S1, NWA 5421—LL3 S2, NWA 5205—LL3 S2, NWA 11905—LL3-5 S3, NWA 5781—LL3 S3, NWA 11351—LL3-6 S4) using optical and electron microscopy and microtomography techniques. Results support a four-stage model for chondrite formation. This includes 1) limited annealing following collisions during chondrule crystallization and rapid cooling in space prior to accretion, as evidenced by olivine microstructures consistent with dislocation …

Deep Adaptive Graph Clustering Via Von Mises-Fisher Distributions, Pengfei Wang, Daqing Wu, Chong Chen, Kunpeng Liu, Yanjie Fu, Jianqiang Huang, Yuanchun Zhou, Jianfeng Zhan, Xiansheng Hua

Computer Science Faculty Publications and Presentations

Graph clustering has been a hot research topic and is widely used in many fields, such as community detection in social networks. Lots of works combining auto-encoder and graph neural networks have been applied to clustering tasks by utilizing node attributes and graph structure. These works usually assumed the inherent parameters (i.e., size and variance) of different clusters in the latent embedding space are homogeneous, and hence the assigned probability is monotonous over the Euclidean distance between node embeddings and centroids. Unfortunately, this assumption usually does not hold since the size and concentration of different clusters can be quite different, …

Quick Guide To Aquatic Weeds Of Oregon, Gabriel E. Campbell, Ashley Newcomb, Jacob Rose

Center for Lakes and Reservoirs Publications and Presentations

This document contains a quick, non-technical, pictured-based field guide to aquatic weed species in Oregon and throughout the Pacific Northwest. It contains approximately 50 common, newly emerging, and watch list exotic weeds and common native look-alike plants. The intended audience for this guide includes weed professionals, restoration practitioners, land managers, professional botanists, and amateur naturalists.

Assessment Of Avian Community Structure And Habitat Connectivity In The Fanno Creek Corridor Bird Surveys, Habitat Assessment, And Management Recommendations, Grace Hall

Environmental Science and Management Professional Master's Project Reports

Urbanization can significantly impact habitat quality and connectivity for avian communities, decreasing species richness and diversity. However, in highly fragmented habitats, urban parks and riparian zones can provide important habitat corridors for birds that facilitate movement and access to essential resources. On the west side of greater Portland, Oregon, Fanno Creek may serve as a habitat corridor for birds and other local wildlife.

Fanno Creek is a 25-kilometer tributary of the Tualatin River that runs through the cities of Portland, Beaverton, Tigard, and Durham in northwestern Oregon. The land surrounding the creek includes residential, commercial, and industrial properties as well …

Flowering Rush (Butomus Umbellatus) Id Guide For The Columbia River, Gabriel Campbell, Jacob Rose

Center for Lakes and Reservoirs Publications and Presentations

This is a picture based field guide for how to identify Flowering Rush (Butomus umbellatus) in the Columbia River throughout Oregon and Washington. It includes how to tell this species from commonly co-occurring look-alike species.

Electromagnetic Fields And Radiation From Localized Current Source Interacting With A Cosmic Axion Field In The Context Of Massive Axion Electrodynamics, Railing Chang, P. T. Leung

Physics Faculty Publications and Presentations

Electromagnetic fields from localized current source interacting with an oscillatory cosmic axion field are studied, accounting for the possibility of a finite photon mass. In particular, focus will be on the dipole radiation from static current sources. The Proca theory is generalized to include the axion field and solutions to the modified EM field equations are obtained to first order in the axion coupling parameter. Analysis of the interplay between the two vanishingly small parameters – the axion mass (via the coupling constant and the oscillating frequency) and the photon mass – is carried out with reference to possible future …

The Use Of Fluorescence Lifetime Imaging (Flim) For In Situ Microbial Detection In Complex Mineral Substrates, Yekaterina G. Chmykh, Jay Nadeau

Physics Faculty Publications and Presentations

The utility of fluorescence lifetime imaging microscopy (FLIM) for identifying bacteria in complex mineral matrices was investigated. Baseline signals from unlabelled Bacillus subtilis and Euglena gracilis, and Bacillus subtilis labelled with SYTO 9 were obtained using two-photon excitation at 730, 750 and 800 nm, identifying characteristic lifetimes of photosynthetic pigments, unpigmented cellular autofluorescence, and SYTO 9. Labelled and unlabelled B. subtilis were seeded onto marble and gypsum samples containing endolithic photosynthetic cyanobacteria and the ability to distinguish cells from mineral autofluorescence and nonspecific dye staining was examined in parallel with ordinary multichannel confocal imaging. It was found that FLIM …

Oregon State Rank Assessment For Pit Roach (Hesperoleucus Mitrulus), Misty Nelson

Institute for Natural Resources Publications

Oregon state conservation status assessment for pit roach (Hesperoleucus mitrulus) using NatureServe methodology, 2023.

The Magmatic Origin Of The Columbia River Gorge, Usa, Nathaniel Klema, Leif Karlstrom, Charles Cannon, Chengxin Jiang, Jim O'Connor, Ray E. Wells, Brandon Schmandt

Geology Faculty Publications and Presentations

Along subduction zones, high-relief topography is associated with sustained volcanism parallel to the plate margin. However, the relationship between magmatism and mountain building in arcs is poorly understood. Here, we study patterns of surface deformation and correlated fluvial knickpoints in the Columbia River Gorge to link long-term magmatism to the uplift and ensuing topographic development of the Cascade Range. An upwarped paleochannel exposed in the walls of the Gorge constrains unsteady deep magma flux, the ratio of intrusive to extrusive magmatic contributions to topography, and the impact of magmatism on Columbia River incision since 3.5 million years ago. Geophysical data …

How Are Oregon's Rural Indigenous Communities Overcoming Water Access Issues?, Tyren John Thompson

Dissertations and Theses

This study investigates how water insecurity affects Indigenous communities in Grand Ronde, Warm Springs, and Umatilla, Oregon, through loss of clean drinking water, access to culturally significant foods, and exposure to pollution. Each community offers innovative solutions drawing on their Indigenous knowledge to overcome water supply challenges. Communities with more resources are better equipped to cope with water insecurity and environmental degradation.

Seeing In The Dark: Towards Robust Pedestrian Detection At Nighttime, Afnan Althoupety

Dissertations and Theses

"At some point in the day, everyone is a pedestrian" a message from the National Highway Traffic Safety Administration (NHTSA) about pedestrian safety. In 2020, NHTSA reported that 6,516 pedestrians were killed in traffic crashes and a pedestrian was killed every 81 minutes on average in the United States. In relation to light condition, 77% of pedestrian fatalities occurred in the dark, 20% in daylight, 2% in dusk, and 2% in dawn.

To tackle the issue from a technological perspective, this dissertation addresses the problem of pedestrian detection robustness in dark conditions, benefiting from image processing and learning-based approaches by: …

Oregon State Rank Assessment For Bonneville Redside Shiner (Richardsonius Balteatus Hydrophlox), Misty Nelson

Institute for Natural Resources Publications

Oregon state conservation status assessment for Bonnevile redside shiner (Richardsonius balteatus hydrophlox) using NatureServe methodology, 2023.

Tiny Drifters Amidst Global Change: Examining Environmental Drivers, Trophic Impacts, And Management Strategies Of Estuarine Plankton Communities In The Anthropocene, Taylor Nicole Dodrill

Dissertations and Theses

Plankton productivity supports estuarine food webs, and has been tied to the success of fisheries, macroinvertebrates, and cultured shellfish yields. Climate change and alterations to nutrient loads are thought to be influencing plankton assemblages, with toxin-producing harmful algal blooms (HABs) on the rise and nutritional quality of plankton declining globally. These shifts in plankton communities may contribute to low biomass yields and toxin-based closures of important fisheries. The objectives of this dissertation are to identify environmental drivers, trophic impacts, and management strategies to understand and respond to changing estuarine plankton communities. To address these objectives, I used a combination of …

The Discovery Of Diverse Picophytoplankton Populations In The Columbia And Willamette Rivers Using Flow Cytometry, Kylee M. Lamberson

Chemistry Undergraduate Departmental Honors Theses

As important primary producers, picophytoplankton determine the flow of carbon and energy in aquatic ecosystems. Picocyanobacteria are one picophytoplankton group known to be dominant in oceans and lakes, but they are still poorly understood in river systems. This project examined picophytoplankton communities in two distinct river systems: the Columbia and Willamette Rivers in Portland, Oregon. I aimed to characterize and quantify the picophytoplankton populations in the context of the environmental conditions of the two rivers. I used flow cytometry to detect cells based on their relative size and pigment fluorescence. I sampled nearly weekly for ten months to capture population …

Province-Wide Tapping Of A Shallow, Variably Depleted, And Metasomatized Mantle To Generate Earliest Flood Basalt Magmas Of The Columbia River Basalt, Northwestern Usa, Martin J. Streck, Luke James Fredenberg, Lena M. Fox, Emily B. Cahoon, Mary J. Mass

Geology Faculty Publications and Presentations

The Miocene Columbia River Basalt Group (CRBG) of the Pacific Northwest of the United States is the world’s youngest and smallest large igneous province. Its earliest formations are the Imnaha, Steens, and now the Picture Gorge Basalt (PGB), and they were sourced from three different dike swarms exposed from SE Washington to Nevada to northcentral Oregon. PGB is often viewed to be distinct from the other formations, as its magmas are sourced from a shallow, relatively depleted, and later subduction-induced metasomatized mantle, along with its young stratigraphic position. It has long been known that the lowermost American Bar flows (AB1&2) …

Preventing Inferences Through Data Dependencies On Sensitive Data, Primal Pappachan, Shufan Zhang, Xi He, Sharad Mehrotra

Computer Science Faculty Publications and Presentations

Simply restricting the computation to non-sensitive part of the data may lead to inferences on sensitive data through data dependencies. Inference control from data dependencies has been studied in the prior work. However, existing solutions either detect and deny queries which may lead to leakage – resulting in poor utility, or only protects against exact reconstruction of the sensitive data – resulting in poor security. In this paper, we present a novel security model called full deniability. Under this stronger security model, any information inferred about sensitive data from non-sensitive data is considered as a leakage. We describe algorithms for …

Gated Recurrent Units For Blockage Mitigation In Mmwave Wireless, Ahmed H. Almutairi, Alireza Keshavarz-Haddad, Ehsan Aryafar

Computer Science Faculty Publications and Presentations

Millimeter-Wave (mmWave) communication is susceptible to blockages, which can significantly reduce the signal strength at the receiver. Mitigating the negative impacts of blockages is a key requirement to ensure reliable and high throughput mmWave communication links. Previous research on blockage mitigation has introduced several model and protocol based blockage mitigation solutions that focus on one technique at a time, such as handoff to a different base station or beam adaptation to the same base station. In this paper, we address the overarching problem: what blockage mitigation method should be employed? and what is the optimal sub-selection within that method? To …

Parameterized Complexity Of Feature Selection For Categorical Data Clustering, Sayan Bandyapadhyay, Fedor V. Fomin, Petr A. Golovach, Kirill Simonov

Computer Science Faculty Publications and Presentations

We develop new algorithmic methods with provable guarantees for feature selection in regard to categorical data clustering. While feature selection is one of the most common approaches to reduce dimensionality in practice, most of the known feature selection methods are heuristics. We study the following mathematical model. We assume that there are some inadvertent (or undesirable) features of the input data that unnecessarily increase the cost of clustering. Consequently, we want to select a subset of the original features from the data such that there is a small-cost clustering on the selected features. More precisely, for given integers ℓ (the …

Coastal Wetland Restoration Through The Lens Of Odum's Theory Of Ecosystem Development, Friedrich W. Keppeler, Annette S. Engel, Linda M. Hooper-Bùi, Paola C. López-Duarte, Charles W. Martin, Jill A. Olin, Katelyn J. Lamb, Michael J. Polito, Nancy N. Rabalais, Multiple Additional Authors

Environmental Science and Management Faculty Publications and Presentations

Advancing ecological restoration assessments requires a more detailed consideration of species interactions and ecosystem processes. Most restoration projects rely on a few metrics not always directly linked with ecological theory. Here, we used Odum's theory of ecosystem development to assess and compare the ecosystem structure and services of created marshes (4–6 years old) with preexisting, reference marshes in a brackish water region of the Mississippi River Delta. We built ecosystem models for created and reference marshes that integrated large datasets of stomach contents, stable isotopes, and taxa abundances. Despite strong resemblance in community structure, created marshes were at an earlier …