Digital Commons Network^™

Equity And Exclusion Issues In Cashless Fare Payment Systems For Public Transportation, Aaron Golub, Anne Brown, Candace Brakewood, John Macarthur, Sangwan Lee, Abubakr Ziedan

Urban Studies and Planning Faculty Publications and Presentations

Many transit agencies in the United States plan to automate their fare collection and limit–or even eliminate–the use of cash fares, with the goals of expediting boarding, collecting data, and lowering costs. Yet about 10% of US adults lack a bank account or credit card, and many rely on restrictive cellphone data plans or do not have access to the internet or a smartphone. These riders will find it difficult to access transit in the future. This paper examines transit users’ experiences with fare technologies using a survey of riders in three cities. Our analysis reveals which riders are most …

Issues With Variability In Electronic Health Record Data About Race And Ethnicity: Descriptive Analysis Of The National Covid Cohort Collaborative Data Enclave, Lily A. Cook Ma, David A. Dorr, Nicole G. Weiskopf, Nisha Mathews, Kelly L. Gonzales, Adam Wilcox, Charisse Madlock-Brown, N3c Consortium

OHSU-PSU School of Public Health Faculty Publications and Presentations

Background:The adverse impact of COVID-19 on marginalized and under-resourced communities of color has highlighted the need for accurate, comprehensive race and ethnicity data. However, a significant technical challenge related to integrating race and ethnicity data in large, consolidated databases is the lack of consistency in how data about race and ethnicity are collected and structured by health care organizations.

Objective:This study aims to evaluate and describe variations in how health care systems collect and report information about the race and ethnicity of their patients and to assess how well these data are integrated when aggregated into a large clinical database. …

Evaluating The Effect Of San Francisco’S Paid Parental Leave Ordinance On Birth Outcomesf, Deborah Karasek, Sarah Raifman, Rita Hamad, William H. Dow, Julia M. Goodman

OHSU-PSU School of Public Health Faculty Publications and Presentations

Since 2017, San Francisco’s Paid Parental Leave Ordinance (PPLO) has allowed parents who work for private-sector employers to take 6 weeks of fully paid postnatal parental leave. Previous studies have linked paid parental leave with health improvements for birthing people and babies, although evidence for birth outcomes is limited. We hypothesized that the PPLO may have improved birth outcomes via reduced stress during pregnancy due to anticipation of increased financial security and postnatal leave. We used linked California birth certificate and hospital discharge records from January 2013 to December 2018 (n = 1,420,781). We used quasi-experimental difference-in-difference (DD) models to …

A New Classification Network For Diagnosing Alzheimer’S Disease In Class-Imbalance Mri Datasets, Ziyang Chen, Zhuowei Wang, Meng Zhao, Qin Zhao, Xuehu Liang, Jiajian Li, Xiaoyu Song

Electrical and Computer Engineering Faculty Publications and Presentations

Automatic identification of Alzheimer’s Disease (AD) through magnetic resonance imaging (MRI) data can eectively assist to doctors diagnose and treat Alzheimer’s. Current methods improve the accuracy of AD recognition, but they are insufficient to address the challenge of small interclass and large intraclass dierences. Some studies attempt to embed patch-level structure in neural networks which enhance pathologic details, but the enormous size and time complexity render these methods unfavorable. Furthermore, several self-attention mechanisms fail to provide contextual information to represent discriminative regions, which limits the performance of these classifiers. In addition, the current loss function is adversely aected by outliers …

Adding Chinese Herbal Medicine To Routine Care Is Associated With A Lower Risk Of Rheumatoid Arthritis Among Patients With Asthma: A Population-Based Retrospective Cohort Study, Wei-Chiao Chang, Hanoch Livneh, Wei-Jen Chen, Chang-Cheng Hsieh, Yu-Han Wang, Ming-Chi Lu, How-Ran Guo, Tzung-Yi Tsai

Counselor Education Faculty Publications and Presentations

Objective: Due to the shared pathogenesis of asthma and rheumatoid arthritis (RA), patients with asthma were found to have a higher risk of RA. While the benefits and safety of Chinese herbal medicine (CHM) for asthma have been reported, the scientific evidence regarding its effect on RA is limited. This longitudinal cohort study aimed to determine the relation between CHM use and RA risk in patients with asthma.

Methods: Using the nationwide claims data, we enrolled 33,963 patients 20–80 years of age who were newly diagnosed with asthma and simultaneously free of RA between 2000 and 2007. From this sample, …

Analyzing Microarchitectural Residue In Various Privilege Strata To Identify Computing Tasks, Tor J. Langehaug

Theses and Dissertations

Modern multi-tasking computer systems run numerous applications simultaneously. These applications must share hardware resources including the Central Processing Unit (CPU) and memory while maximizing each application’s performance. Tasks executing in this shared environment leave residue which should not reveal information. This dissertation applies machine learning and statistical analysis to evaluate task residue as footprints which can be correlated to identify tasks. The concept of privilege strata, drawn from an analogy with physical geology, organizes the investigation into the User, Operating System, and Hardware privilege strata. In the User Stratum, an adversary perspective is taken to build an interrogator program that …

Enabling Rapid Chemical Analysis Of Plutonium Alloys Via Machine Learning-Enhanced Atomic Spectroscopy Techniques, Ashwin P. Rao

Theses and Dissertations

Analytical atomic spectroscopy methods have the potential to provide solutions for rapid, high fidelity chemical analysis of plutonium alloys. Implementing these methods with advanced analytical techniques can help reduce the chemical analysis time needed for plutonium pit production, directly enabling the 80 pit-per-year by 2030 manufacturing goal outlined in the 2018 Nuclear Posture Review. Two commercial, handheld elemental analyzers were validated for potential in situ analysis of Pu. A handheld XRF device was able to detect gallium in a Pu surrogate matrix with a detection limit of 0.002 wt% and a mean error of 8%. A handheld LIBS device was …

Multichannel Blind Deconvolution Of Circularly Polarized Imagery, Patrick B. Cunningham

Theses and Dissertations

Current methods can be used to recreate an expected Stokes polarization vector from measured light for characterization purposes. However, this only applies to three of the Stokes parameters, that is, the linear polarization components. Circular polarization is not currently being utilized for object characterization because the mathematical complexity is greater than for that of linear polarization. This research will analyze a way to expand existing algorithms to include circular polarization and enable the complete reconstruction of the Stokes vector from the measured light into a blind deconvolution algorithm for Stokes estimation and image reconstruction.

Quantum Error Detection Without Using Ancilla Qubits, Nicolas Guerrero

Theses and Dissertations

Quantum computers are beset by errors from a variety of sources. Although quantum error correction and detection codes have been developed since the 1990s, these codes require mid-circuit measurements in order to operate. In order to avoid these measurements we have developed a new error detection code that only requires state collapses at the end of the circuit, which we call no ancilla error detection (NAED). We investigate some of the mathematics behind NAED such as which codes can detect which errors. We then run NAED on three separate types of circuits: Greenberger–Horne–Zeilinger circuits, phase dependent circuits, and a quantum …

Additive Manufacturing Of Molybdenum For High Temperature Structural Applications, Megan L. Bustin

Theses and Dissertations

This research considered additive manufactured (AM) molybdenum (Mo) and the effect of three variables on microstructure, mechanical properties, and the relationship between the two. Test temperature, laser speed, and shield gas or build atmosphere were varied, and samples tested and analyzed using a three-point bending test, chemical composition, and optical and scanning electron microscopy. The relationship among variables and results using a Design of Experiments was limited compared to the inclusion of every tested sample. Most effects were expected: samples tested at room temperature were brittle without statistical significance; increasing laser speed resulted in decreased ductility and strain, smaller grain …

Mechanical Properties And Tension-Tension Fatigue Behavior Of A Novel Additively Manufactured Polymer Matrix Composite At Room And Elevated Temperature, Grayson M. Harber

Theses and Dissertations

The tension-tension fatigue behavior of a novel additively manufactured AM carbon fiber reinforced polymer matrix composite was studied. This novel material system consists of T1100 carbon fibers, and a UV photocured resin developed by Continuous Composites and Sartomer. Tensile properties and tension-tension fatigue were investigated for the 090 fiber orientation as well as for the ±45 fiber orientation. Specimens with 0/90 fiber orientation were tested at ambient laboratory temperature 23 °C and at elevated temperature 150 °C, while the specimens with the ±45 fiber orientation were tested only at ambient laboratory temperature. Tension-tension fatigue testing was carried out with a …

Leveraging Subject Matter Expertise To Optimize Machine Learning Techniques For Air And Space Applications, Philip Y. Cho

Theses and Dissertations

We develop new machine learning and statistical methods that are tailored for Air and Space applications through the incorporation of subject matter expertise. In particular, we focus on three separate research thrusts that each represents a different type of subject matter knowledge, modeling approach, and application. In our first thrust, we incorporate knowledge of natural phenomena to design a neural network algorithm for localizing point defects in transmission electron microscopy (TEM) images of crystalline materials. In our second research thrust, we use Bayesian feature selection and regression to analyze the relationship between fighter pilot attributes and flight mishap rates. We …

Orthogonal Arrays And Legendre Pairs, Kristopher N. Kilpatrick

Theses and Dissertations

Well-designed experiments greatly improve test and evaluation. Efficient experiments reduce the cost and time of running tests while improving the quality of the information obtained. Orthogonal Arrays (OAs) and Hadamard matrices are used as designed experiments to glean as much information as possible about a process with limited resources. However, constructing OAs and Hadamard matrices in general is a very difficult problem. Finding Legendre pairs (LPs) results in the construction of Hadamard matrices. This research studies the classification problem of OAs and the existence problem of LPs. In doing so, it makes two contributions to the discipline. First, it improves …

Orbit Determination With Event-Based Cameras To Improve Space Domain Awareness, Conor M. Wisentaner

Theses and Dissertations

The objective of this research is to assess the utility of a COTS EBC for SDA applications by evaluating its ability to produce data for orbit updates of resident space objects. Unlike traditional frame-based imaging sensors, the pixels on an EBC activate independently when a change in brightness is detected to produce a continuous data flow on a per pixel basis. This unique functionality provides much higher temporal resolution than traditional frame-based sensors, such that an EBC can generate far more data points from a single observation than a frame-based sensor. However, current COTS EBCs have less spatial resolution than …

Cost-Benefit Analysis Of The Saudi Land Bridge Project, Faris J. Alotaibi

Theses and Dissertations

Projects are the backbone of economic thrive of nations, especially infrastructure projects. It’s counted as the base layer of allowing economic trade between beneficiaries. Railway projects have always been a huge element in increasing trade operations between Saudi Arabia and the rest of the world, by providing an efficient and environmentally friendly way that is capable of hauling large loads of exports all the way to the seaports and from there to the rest of the world. The Saudi land bridge project will cost about $11 billion and will provide a new link between the existent railway in the eastern …

Evaluating Performance Competencies In The Royal Saudi Air Force Engineering Directorate And Squadrons, Faisal A. Al Dawood

Theses and Dissertations

The effectiveness of tasks performed by the directorate of aeronautical engineering and squadrons in RSAF directly impacts flight safety, which in turn influences the organization either positively or negatively. Therefore, improving engineers' competencies will improve the overall performance of the organization. The study refined and reconstructed a model, namely a T-shape competency model, to assess the engineers' competencies which revealed some management and competency-related deficiencies and concluded with managerial recommendations.

Modern Approaches And Theoretical Extensions To The Multivariate Kolmogorov Smirnov Test, Gonzalo Hernando

Theses and Dissertations

Most statistical tests are fully developed for univariate data, but when inference is required for multivariate data, univariate tests risk information loss and interpretability. This research 1) derives and extends the multivariate Komolgorov Smirnov test for 2 and into m-dimensions, 2) derives small sample critical values for the KS test that are not reliant on sample size simulations or correlation between variables, 3) extends large sample estimations and current KS implementations, and 4) provides sample size and power calculations in order to enable experimental design with respect to testing for differences in distributions. Through extensive simulation, we demonstrate that our …

Development Of A Security-Focused Multi-Channel Communication Protocol And Associated Quality Of Secure Service (Qoss) Metrics, Paul M. Simon

Theses and Dissertations

The threat of eavesdropping, and the challenge of recognizing and correcting for corrupted or suppressed information in communication systems is a consistent challenge. Effectively managing protection mechanisms requires an ability to accurately gauge the likelihood or severity of a threat, and adapt the security features available in a system to mitigate the threat. This research focuses on the design and development of a security-focused communication protocol at the session-layer based on a re-prioritized communication architecture model and associated metrics. From a probabilistic model that considers data leakage and data corruption as surrogates for breaches of confidentiality and integrity, a set …

Retention Prediction And Policy Optimization For United States Air Force Personnel Management, Joseph C. Hoecherl

Theses and Dissertations

Effective personnel management policies in the United States Air Force (USAF) require methods to predict the number of personnel who will remain in the USAF as well as to replenish personnel with different skillsets over time as they depart. To improve retention predictions, we develop and test traditional random forest models and feedforward neural networks as well as partially autoregressive forms of both, outperforming the benchmark on a test dataset by 62.8% and 34.8% for the neural network and the partially autoregressive neural network, respectively. We formulate the workforce replenishment problem as a Markov decision process for active duty enlisted …

Improving Country Conflict And Peace Modeling: Datasets, Imputations, And Hierarchical Clustering, Benjamin D. Leiby

Theses and Dissertations

Many disparate datasets exist that provide country attributes covering political, economic, and social aspects. Unfortunately, this data often does not include all countries nor is the data complete for those countries included, as measured by the dataset’s missingness. This research addresses these dataset shortfalls in predicting country instability by considering country attributes in all aspects as well as in greater thresholds of missingness. First, a structured summary of past research is presented framed by a developed casual taxonomy and functional ontology. Additionally, a novel imputation technique for very large datasets is presented to account for moderate missingness in the expanded …

Efficiency Quantification For Pulsed-Source Digital Holographic Wavefront Sensing, Steven A. Owens

Theses and Dissertations

The efficiencies of a digital holography (DH) system in the pulsed configuration and the off-axis image plane recording geometry are analyzed. First, the system efficiencies of an infrared-wavelength DH system in a homodyne-pulsed configuration are measured and compared to those of a visible-wavelength DH system in a homodyne-continuous-wave (CW) configuration. The total-system, excess-reference-noise, shot-noise-limit, and mixing efficiencies of the pulsed-source system were found to be consistent with those of the CW-source system. This indicated no new efficiencies were necessary to characterize pulsed-source systems when no temporal delay exists between the pulses. The consistency of efficiencies also showed infrared DH systems …

A Case Study Of The Efficacy Of Model-Based Requests For Information, Kyle J. Arruda

Theses and Dissertations

The Department of Defense (DoD) has encouraged the transition to digital engineering, yet there are limited guides for how to transition and there is limited data to show where an organization like a program office can reap the most benefit from the transition. To identify areas where potential benefits may be realized, this thesis compares two Requests for Information (RFIs), one document-based and one model-based, from generation to response. A survey was developed and administered to 7 members of a single program office to grade the RFI responses. The survey was based on the 43 benefit categories identified in the …

Optimizing Optical Switching Of Non-Linear Hyperbolic Metamaterials, James A. Ethridge

Theses and Dissertations

Modern optical materials are engineered to be used as optical devices in specific applications, such as optical computing. For optical computing, efficient forms of a particular device, the optical switch, still have not been successfully demonstrated. This problem is addressed in this research through the use of designed optical metamaterials, specifically, hyperbolic metamaterials, which offer the possibility of large non-linear properties with a low switching intensity. One-dimensional layered hyperbolic metamaterials composed of alternating layers of metal and dielectric were used here, with ITO as the metal and SiO₂ as the dielectric. The non-linear behavior of the ITO/SiO₂ layered …

Value Focused Thinking Analysis Of C-Band Australia Radar Operations, Samuel Ray Grothman

Theses and Dissertations

The radars used for Space Domain Awareness (SDA) are inherently all-weather, day/night sensors capable of around the clock operations. Despite this fact, some radars are operated for fewer than their maximum operating capabilities. The decision-making process for selecting the operating hours of a sensor has historically been based on only a few factors or just one. This research uses the techniques in Value Focused Thinking to develop an evaluation process to score possible alternatives and find the alternative with the most value for the decision maker. By investigating the value that is added by operating an SDA radar, it is …

Generative Methods, Meta-Learning, And Meta-Heuristics For Robust Cyber Defense, Marc W. Chalé

Theses and Dissertations

Cyberspace is the digital communications network that supports the internet of battlefield things (IoBT), the model by which defense-centric sensors, computers, actuators and humans are digitally connected. A secure IoBT infrastructure facilitates real time implementation of the observe, orient, decide, act (OODA) loop across distributed subsystems. Successful hacking efforts by cyber criminals and strategic adversaries suggest that cyber systems such as the IoBT are not secure. Three lines of effort demonstrate a path towards a more robust IoBT. First, a baseline data set of enterprise cyber network traffic was collected and modelled with generative methods allowing the generation of realistic, …

Statistical Inference On Desirability Function Optimal Points To Evaluate Multi-Objective Response Surfaces, Peter A. Calhoun

Theses and Dissertations

A shortfall of the Derringer and Suich (1980) desirability function is lack of inferential methods to quantify uncertainty. Most articles for addressing uncertainty usually involve robust methods, providing a point estimate that is less affected by variation. Few articles address confidence intervals or bands but not specifically for the Derringer and Suich method. This research provides two valuable contributions to the field of response surface methodology. The first contribution is evaluating the effect of correlation and plane angles on Derringer and Suich optimal solutions. The second contribution proposes and compares 8 inferential methods--both univariate and multivariate--for creating confidence intervals on …

Using Blockchain To Track Dod Funding And Auditing, Prithvi Prasanna

Theses and Dissertations

The Department of Defense (DoD) currently faces a significant problem when it comes to auditing and tracking financial transactions. The DoD has failed every audit since 2017 although it is gradually improving its auditable rating year after year. Concurrently, Blockchain is an emerging technology that has typically been used for cryptocurrencies but has slowly been adapted by private enterprises for their auditing and invoicing problems. This study investigates the value proposition of blockchain technology to improve DoD financial tracking and auditing. To test the hypothesis that blockchain is the optimal option for the DoD, this paper employs an industry blockchain …

A Methodological Framework For Parametric Combat Analysis, Dustin L. Hayhurst Sr.

Theses and Dissertations

This work presents a taxonomic structure for understanding the tension between certain factors of stability for game-theoretic outcomes such as Nash optimality, Pareto optimality, and balance optimality and then applies such game-theoretic concepts to the advancement of strategic thought on spacepower. This work successfully adapts and applies combat modeling theory to the evaluation of cislunar space conflict. This work provides evidence that the reliability characteristics of small spacecraft share similarities to the reliability characteristics of large spacecraft. Using these novel foundational concepts, this dissertation develops and presents a parametric methodological framework capable of analyzing the efficacy of heterogeneous force compositions …

Coronavirus Disease-19 Infection And Angioedema In African Americans: A Case Series, Jose Manuel Martinez Manzano, Otoniel Ysea-Hill, Brenda Chiang, Simone A Jarrett, Kevin Bryan Lo, Zurab Azmaiparashvili

Department of Medicine Faculty Papers

Rationale: Few case series have described the simultaneous development of angioedema in patients with coronavirus 19 disease (COVID-19). Most of these reports were described in at-risk patients for developing bradykinin angioedema. Therefore, we aim to describe 5 African American patients who developed simultaneous COVID-19 and angioedema.

Methods: This was a case series of hospitalized patients with simultaneous angioedema and COVID-19 infection in a single center from May 2020 to February 2022. We used descriptive statistics. The study was approved by the institutional review board.

Results: Their median age was 55 years (range 28-66); all patients were African American, and 3/5 …

The Impact Of The Covid-19 Pandemic On The Career Choice Of Medicine: A Cross-Sectional Study Amongst Pre-Medical Students In Pakistan, Raisa Saleh, Russell Seth Martins, Muhammad Saad, Asad Saulat Fatimi, Manzar Abbas, Inaara Akbar, Hamzah Jehanzeb, Shamila Ladak, Shamama Kaleem, Sarah Nadeem

Medical College Documents

Background: The COVID-19 pandemic has significantly affected the lives of healthcare workers due to the frontline nature of their work. Their hard work and sacrifice have forged new perceptions of healthcare workers. These changes may potentially influence students' interest in medicine. This study explores how the COVID-19 pandemic has affected premedical students' decisions to pursue medicine as a career.
Methods: A cross-sectional study using a self-designed online questionnaire was carried out amongst pre-medical students across Pakistan.
Results: A total of 1695 students from 93 public and private schools filled in the survey. After the onset of the COVID-19 pandemic, significantly …