Digital Commons Network^™

Mud Acoustics, Charles W. Holland, Stan E. Dosso, Jason D. Chaytor

Electrical and Computer Engineering Faculty Publications and Presentations

Imaging the ocean requires an understanding of how different seafloor sediments interact with sound waves.

Data From: Active Transportation Counts From Existing On-Street Signal And Detection Infrastructure, Sirisha Kothuri, Patrick Allen Singleton, Mahyar Vahedi Saheli, Elizabeth Yates, Joseph P. Broach

Civil and Environmental Engineering Faculty Datasets

This study’s objective was to use data from existing traffic signal infrastructure to estimate pedestrian volumes. Pedestrian push-button actuations were collected from signal controller logs at 49 intersections in western Oregon and an additional 16 intersections in eastern Oregon. These actuations were then compared to observed pedestrian counts, totaling over 34,000 people, obtained from video recordings. After exploring various options, a simple quadratic relationship was modeled using a single measure of pedestrian signal activity: the number of push-button presses (filtered to remove multiple presses within 15 seconds). The model’s predictions showed a correlation of 0.86 with observed pedestrian volumes and …

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, …

Developing An Assessment Model For Entrepreneurship Ecosystems Using Hierarchical Decision Model, Mustafa Almuzel, Tugrul U. Daim, Birol Yesilada, Marina Dabic, Gulin Idil Bolatan

Engineering and Technology Management Faculty Publications and Presentations

Entrepreneurship is a crucial driver of economic growth, necessitating the development of effective entrepreneurial ecosystems. However, there are significant gaps in the literature regarding the structured assessment of these ecosystems. This study addresses three main research gaps: the lack of structured evaluation methods, the need for a comprehensive analysis of ecosystem challenges from various perspectives, and the identification of critical factors essential for ecosystem growth. To bridge these gaps, the research introduces the Hierarchical Decision Model (HDM) as a universal assessment framework that can be adapted to different cities for creating effective entrepreneurial environments. The research methodology involved formulating perspectives …

Raps Sheet, January 2024, Retirement Association Of Portland State

RAPS Sheet: Monthly Newsletter

No abstract provided.

Housing Choice, Transportation Equity, And Access To Opportunities In Refugee And Immigrant Communities, Diane Mitschke, Anne Nordberg, Stephen Mattingly, Katherine Kitchens

TREC Final Reports

Mobility directly impacts access to opportunities for all protected classes; however, transportation planning and public transit agencies and housing authorities rarely coordinate affordable housing and the transportation system planning decisions. This lack of coordination often leads to mismatches between access to opportunities and affordable housing. Safe access to employment, quality schools, and healthcare represent a few of the many factors that may influence housing choice. For most households with budget constraints, all of these factors may not be achievable. While existing research documents the mismatch between affordable housing and access to opportunities, the role that mobility plays in residential selection …

Shame And History, Bennett B. Gilbert

University Studies Faculty Publications and Presentations

If history—our past, the sum of our thoughts, passions, and deeds—is so pervasive, influential, and meaningful, why then do we lose sight of it? Why do we not gain good values from it? And if it is part of our existential core, why then do we so often fail to ravel it into our deliberations?

I propose that very often and to a great degree it is shame that separates us from history. Shame: garrulous, compulsive, intense, omnivorous. A shamed person pushes away the experiences that shame her, thus cutting off the past.

Looking At The Past To Change The Future: Showcasing Featured Collections, Building Communities, And Co-Creating, Sherry Buchanan

Library Faculty and Staff Publications and Presentations

Academic libraries have the opportunity and the responsibility to promote and advance content that creates transformative and iterative learning opportunities. To that end, and in an effort to build communities and facilitate co-creation, Portland State University showcases three main Featured Collections in our open access repository, PDXScholar: Climate Justice, COVID-19, and Racial and Gender Equity, with a fourth pilot collection—Student Work: An Open Showcase of Outstanding Student-Created Research & Creative Work—under development. The collections include a broad range of audiovisual materials, such as podcasts and webinar series, as well as sustainability and equity work, student-created content, and numerous future-focused multidisciplinary …

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 …

Aquatic Invasive Species Survey And Treatment On Lake Umatilla And Lake Celilo 2024-2025 Report, Jacob Rose, Gabriel E. Campbell

Center for Lakes and Reservoirs Publications and Presentations

Flowering Rush (Butomus umbellatus) is an invasive aquatic plant in the Pacific Northwest that threatens salmon habitat. The Center for Lakes and Reservoirs staff surveyed for this and other aquatic species from 2024 and 2025 in the Columbia River in Lake Umatilla and Lake Celilo. This document summarizes their survey efforts including their protocols, data, and small-scale removal efforts.

Sharing Stories Of Hope And Transformation In U.S. Higher Education: An Ereader By Portland State University Students, Óscar Fernández, David Peterson Del Mar

PDXOpen: Open Educational Resources

This eReader showcases stories of hope and transformation written by diverse students enrolled in University Studies courses at Portland State University. The goal is to motivate first-year and transfer students to see that, in higher education, they are not alone in their personal, familial, and academic struggles—and personal, familial, and educational achievements.

Automation Of Productive Machinery. Bases For An Innovative Business Model, Carlos Guillermo Hernández-Cenzano, Angel Contreras-Cruz, Eduardo Humada-Tello

Engineering and Technology Management Faculty Publications and Presentations

Nowadays, some laboratories perform elastic properties tests for concrete or rock cores using equipment manufactured 50 years ago. The original data collection procedure uses analog and manual recordings, which can cause inaccuracies in the measurements taken during these trials The process is tedious and updated since each trial's measurement data is recorded manually. In this context, this study systematizes the process and proposes an automated data acquisition and recording system for this type of equipment, followed by a case study presenting a rock compression test.

Airframe Stability And Recovery For Launch Vehicle No. 3.1, Samantha Bechtel

Maseeh Summer Undergraduate Research Experience

This project presents the airframe stability analysis and recovery system design for Launch Vehicle No. 3.1 (LV3.1) at the Portland State Aerospace Society. Rocket stability relies on maintaining the center of gravity (CG) above the center of pressure (CP). Component masses were modeled in Onshape CAD and simulated in OpenRocket, yielding a stability margin of 2.7 cal for LV3.1. This meets the minimum stability requirement of 2 cal or greater for reaching Mach 1.041 and an apogee of 14,584 ft. Airframe weight was minimized using lightweight materials—including carbon fiber, 3D-printed parts, and aluminum modules machined with an isogrid pattern. For …

Improved Quartz Tube Furnace For Wildfire Condition Testing, Casey Coffland

Maseeh Summer Undergraduate Research Experience

This research presents improvements to a Quartz Tube Furnace used for wildfire condition testing at the Healthy Buildings Research Lab at Portland State University. The primary objectives were to enable the calculation of modified combustion efficiency (M.C.E.), recharacterize internal tube temperatures at 400°C and 650°C, and allow furnace control independent of a laptop. CO₂ and particulate matter sensors were added at the inlet and outlet of the apparatus to collect emissions data during biomass combustion (Douglas Fir pine needles), which a microcontroller uses to calculate M.C.E.. Temperature recharacterization revealed that the internal temperature of the quartz tube was approximately 150°C …

Improving Cvd Graphene Growth On Copper Micro Powders By Manipulating Annealing Environments, Adan Velasquez

Maseeh Summer Undergraduate Research Experience

Recent advances in Cu-composite materials show Cu powder coated with graphene can be used to create composites with exceptional mechanical and conductive properties. However, coating Cu with graphene faces challenges such as adhesion and graphene quality. We employed chemical vapor deposition (CVD) to grow high quality graphene directly on Cu micro powders by manipulating annealing environments. We used scanning electron microscopy (SEM) to image the Cu microparticle’s surfaces at high resolution. To assess and verify the graphene's quality, we use Raman spectroscopy. Nitrogen and hydrogen gases are used during annealing to texture the Cu surface and reduce sintering, respectively, creating …

Comparing The Sensitivity And Degree Of Boolean Functions Via The Hypercube, Annie Rupp

Maseeh Summer Undergraduate Research Experience

This research explores the relationships between various complexity measures of Boolean functions—specifically Query Complexity, Sensitivity, Spectral Sensitivity, and Degree—modeled via hypercube sensitivity graphs and adjacency matrices. While the theoretical bounds for total functions are generalized, it remains unknown whether a function exists where these measures are perfectly equal. Focusing on the tight bounds demonstrated by the OR and PARITY functions, this work outlines a future research framework utilizing a contradiction proof style. By assuming and reverse-engineering established proofs, the study aims to uncover mathematical contradictions that could definitively determine the existence of such a total function.

Influence Of Renewable Energy Into Power Systems, Cristian Gomez

Maseeh Summer Undergraduate Research Experience

Renewable Energy Sources (RESs) like wind, solar photovoltaic, and bioenergy are great because they have low or zero carbon emissions, making them ideal for the environment. However, RESs are not perfect their dependence on weather and their non-existent inertia poses a threat for power systems. Integration of RESs would inadvertently reduce the overall inertia of the grid, increasing the risk of frequency events. Therefore, RESs pose significant challenges to the traditional power system’s ability to manage frequency stability effectively. The objective of this research is to discover the effects of RESs into the Western Interconnection. The increase in ROCOF from …

Exploring Real-Time Robotic Control Using Synthetic Neural Systems, Daniel Restrepo

Maseeh Summer Undergraduate Research Experience

Central Pattern Generators (CPGs) are neural circuits found in the spinal cords of many animals. They are responsible for generating computationally efficient rhythmic outputs used in locomotion, limb manipulation, breathing, and intestinal contraction/relaxation. Traditional robotic control models, such as non-spiking neural networks or Proportional-Integral-Derivative (PID) control systems, although faster to simulate, have limitations in handling adaptive and complex tasks. Spiking CPGs, which mimic real neurons by communicating through discrete spikes, are particularly robust in the presence of environmental noise or changes, resulting in more energy-efficient and dynamic behavior. The aim of this research project is to evaluate the NVIDIA Jetson …

Investigating The Role Of 1-Wire In Low-Power, Crystal-Free Sensor Networks, Mitch Montee

Maseeh Summer Undergraduate Research Experience

We present an investigation into implementing a 1-Wire driver on the Single-Chip Micro Mote (SCµM), a crystal-free, low-power system-on-chip designed for wireless sensor networks. Because SCµM omits a traditional crystal oscillator to maintain a minimal form factor, it relies on an LC tank oscillator, introducing phase noise and clock jitter. To address timing sensitivities, a 1-Wire driver and corresponding bus hardware were developed and integrated into the open-source OpenWSN protocol stack. Performance evaluations across 100 and 1,000 data transfers demonstrated a 0% error rate under both high-frequency (HF_CLOCK) and low-frequency (LF_CLOCK) clock sources using CRC validation.

Generating Magnetic Fields From An Orbital Simulator, Emily Snodgrass

Maseeh Summer Undergraduate Research Experience

This project focuses on generating magnetic fields from an orbital simulator to test satellite hardware during space missions. Using Basilisk, a simulation framework that references a model for Earth's magnetic field. To recreate these environmental conditions on Earth, the project uses a Helmholtz cage. Running a current through the pairs of coils controls the magnetic field in the center, to simulate the magnetic field that a satellite would experience at any point in its orbit. Future work will involve running a full hardware in the loop simulation that changes the magnetic field in the cage as the Basilisk values change, …

Impact Of Cuticular Conductance On Foliar Water Uptake In Fagus Grandifolia, Rory Price

Maseeh Summer Undergraduate Research Experience

Foliar water uptake (FWU) is a process many trees and plants use to uptake water vapor into their leaves. They do so through several pathways: stomata, the leaf cuticle, trichomes, and hydathodes. This research focuses on modeling stomatal and cuticular conductance in saturated and unsaturated systems. By creating a comprehensive model, it will be possible to predict the impact of drought and other climate changes on ecosystems, water availability, and the water/carbon budget for different regions. Cuticular conductance could be removed or left out of climate models but can offer some insights. By including cuticular conductance values in the model …

Deformation And Coalescence Of Two Impacting Droplets In Microgravity, Cabala Newell

Maseeh Summer Undergraduate Research Experience

Collision of two water droplets between one and two milliliters in microgravity environment is investigated. Multiple differing papers have been written that experiment with droplets in microgravity or theorize about how two droplets suspended in microgravity may mix but this is the first instance in which experiments are being conducted. These Collisions directly impact what's known about practical fluid mixing in microgravity, liquid sprays, and microfluidics focusing on droplet fusion. Tracking these droplets during the collision process is expected to give velocity trends similar to the graph above, where both droplets reach 0 velocity when they coalesce into a single …

App-Based Data Collection To Characterize Latent Transportation Demand Within Marginalized And Underserved Populations, Noelle L. Fields, Courtney Cronley, Stephen Mattingly, Nicole Iroz-Elardo, David Levine, Nithisha Gudipati, Cristine Highfill, Mary Kris Stringfelllow, Anna O'Dell, Rebecca Cole, Melody Huslage

TREC Final Reports

Our interdisciplinary team refined an app prototype, MyAmble, to gather data related to quantity of transportation disadvantage and latent demand, and to identify psycho-social-economic corollaries. MyAmble utilizes a traditional travel diary format but expands the type of trips measured to include 1) completed trips, 2) missed trips, and 3) latent travel demand. The app also measures the real-time perceived impact of transportation behaviors (realized and latent) on participants’ physical health, mental health, social engagement, and employment/academics. Finally, the app has a text-messaging feature, Travel Buddy, that is used to increase participant engagement and retention over longitudinal data collection. The project …

A Transverse-Flux Constant Force Mechanism, Gozde Sivka, Bertrand Dechant, Colton Bruce, Jonathan Z. Bird

Electrical and Computer Engineering Faculty Publications and Presentations

A new type of constant force magnet mechanism is presented that relies on the interaction of magnets alone to create a constant force over a prescribed stroke length. It is demonstrated that by using a transverse field path a very uniform radial field along the travel length is created. This can then be used to create a constant force over a long stroke length. The constat force value is shown to be adjustable through the rotation of the stator relative to the translator. The operating principle of the presented transverse-flux constant force mechanism is validated by using 3-D finite element …

Enhancing Translation Validation Of Compiler Transformations With Large Language Models, Fei Xie, Yanzhao Wang

Computer Science Faculty Publications and Presentations

This paper presents a framework that integrates Large Language Models (LLMs) into translation validation, targeting LLVM compiler transformations where formal verification tools fall short. Our framework first utilizes existing formal verification tools for translation validation. In this work, we use Alive2, a well-known tool in LLVM compiler verification, as an example. When formal verification tools are unable to confirm a transformation's soundness, our framework employs fine-tuned LLMs for prediction. It then applies fuzzing to transformations predicted as potentially unsound by the LLMs due to return values or memory inconsistencies, aiming to find counterexamples. In cases where transformations are unsound for …

Barriers And Variable Spacing Enhance Convective Cooling And Increase Power Output In Solar Pv Plants, Brooke Stanislawski, Todd Harman, Raul Bayoan Cal, Marc Calaf

Mechanical and Materials Engineering Faculty Publications and Presentations

When the temperature of solar photovoltaic (PV) modules rises, efficiency drops and module degradation accelerates. Thus, it is beneficial to reduce module operating temperatures. Previous studies of solar power plants have illustrated that incoming flow characteristics, turbulent mixing, and array geometry can strongly impact convective cooling, as measured by the convective heat transfer coefficient h. In the fields of heat transfer and plant canopy flow, previous work has shown that system-scale arrangement modifications—e.g., variable spacing, barriers, or windbreaks—can passively alter the flow, enhance turbulent mixing, and influence convection. However, researchers have not yet explored how variable spacing or barriers …

Experimental And Modeled Assessment Of Interventions To Reduce Pm2.5 In A Residence During Awildfire Event, Chrissi Argyro Antonopoulos, H. E. Dillon, Elliott T. Gall

Mechanical and Materials Engineering Faculty Publications and Presentations

Increasingly large and frequent wildfires affect air quality even indoors by emitting and dispersing fine/ultrafine particulate matter known to pose health risks to residents. With this health threat, we are working to help the building science community develop simplified tools that may be used to estimate impacts to large numbers of homes based on high-level housing characteristics. In addition to reviewing literature sources, we performed an experiment to evaluate interventions to mitigate degraded indoor air quality. We instrumented one residence for one week during an extreme wildfire event in the Pacific Northwest. Outdoor ambient concentrations of PM_2.5 reached historic …

Uncertainty Quantification Of Live Load Effect In Buried Rc Box Culverts, Mohd Firoj

Dissertations and Theses

Although buried and mostly invisible to the traveling public, bridge-sized culverts (i.e., culverts with span around or longer than 20 ft) account for a large proportion of state-managed bridges. As per Oregon Department of Transportation inventory, there are approximately 35,000 culverts in the state highway system. Among them, 10,862 are in poor conditions and need to be analyzed for load rating purposes. The prediction and understanding of live load effects in culverts are crucial to the design, evaluation, and life-cycle maintenance of culverts. These live load effects include maximum bending moments and shear forces at different critical cross sections.

This …

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 …

Polycyclic Aromatic Hydrocarbons (Pahs) In Wildfire Smoke Accumulate On Indoor Materials And Create Post-Smoke Event Exposure Pathways, Aurélie Laguerre, Elliott T. Gall

Mechanical and Materials Engineering Faculty Publications and Presentations

Wildfire smoke contains PAHs that, after infiltrating indoors, accumulate on indoor materials through particle deposition and partitioning from air. We report the magnitude and persistence of select surface associated PAHs on three common indoor materials: glass, cotton, and mechanical air filter media. Materials were loaded with PAHs through both spiking with standards and exposure to a wildfire smoke proxy. Loaded materials were aged indoors over ~4 months to determine PAH persistence. For materials spiked with standards, total PAH decay rates were 0.010±0.002, 0.025±0.005, and 0.051±0.009 d -1 , for mechanical air filter media, glass, and cotton, respectively. PAH decay on …