Digital Commons Network^™

Automated Sentiment Analysis For Personnel Survey Data In The Us Air Force Context, Julia M. Haines

Theses and Dissertations

When surveys are distributed across the Air Force (AF), whether it be an employee engagement survey, a climate survey, or similar, significant resources are put towards the development, distribution and analysis of the survey. However, when open ended questions are included on these surveys, respondent comments are generally underutilized, more often treated as a source for pull-quotes rather than a data source in and of themselves. This is due to a lack of transparency and confidence in the accuracy of machine-aided methods such as sentiment analysis and topic modeling. This confidence reduces further when the text has special context, such …

The Impact Of Triage Classification Errors On Military Medical Evacuation System Performance, Emily S. Graves

Theses and Dissertations

In a deployed environment, evacuation requests of injured personnel are serviced by multiple forms of evacuation including medical evacuation (MEDEVAC) and casualty evacuation (CASEVAC). This thesis focuses on the optimal dispatching policy for MEDEVAC units when triage classification errors and blood transfusion kits are considered. A discounted, infinite-horizon Markov decision process (MDP) model is formulated to analyze the MEDEVAC dispatching problem and determine the optimal policy based on the status of the MEDEVAC units in the system, the priority level of incoming requests, and the locations from which requests originate. A notional, representational scenario based in Azerbaijan is utilized to …

Examining Crucial Demographic Trends In General Aviation, Joshua D. Meyer

Theses and Dissertations

America's General Aviation sector has witnessed significant demographic shifts since the turn of the century. The number of certified, private pilots, non-fatal aircraft accidents, fatal aircraft accidents, and number of general aviation hours flown are all in decline. Meanwhile, the average age of an American private pilot has increased by several years. All of these factors indicate that the industry is in decline. This study determined via mathematical, linear regression that times relationship to the number of annual, fatal General Aviation accidents and the number of certified private pilots is negative. It also proved that the average age of the …

Behavior Of Lightning In Developing Storms, Erick A. Tello

Theses and Dissertations

Air Force weather squadrons issue a warning when lightning activity is observed within 5 nautical miles (NM) of protected areas. Upon receiving this warning, personnel outdoors are expected to pause work and move inside. Studies sponsored by the 45th Weather Squadron (45 WS) have concluded that the 5 NM warning radius can be safely reduced for well-developed storms. This thesis investigates whether radii for storms in early development can also be reduced. Our research develops algorithms to partition lightning sensor data into storms. Next, storms are filtered to their earliest lightning events, and the study calculates distances between successive early …

Utilizing Model Based Systems Engineering To Identify Safety Critical Functions In Airworthiness Certification, Jeffrey C. King

Theses and Dissertations

Modern aircraft are complex systems with numerous interacting hardware and software components. To minimize any safety mishaps during operations, new aircraft designs and modifications must go through an airworthiness certification. The current United States Air Force (USAF) airworthiness certification process, captured in MIL-HDBK-516C, is time-consuming and manpower intensive due to extensive documentation. To minimize inefficiencies of this document-based approach, this thesis examined model-based systems engineering (MBSE) to support Safety Critical Function (SCF) thread analysis against criteria found in Section 15 of MIL-HDBK-516C. Within this scope, the research identified an SCF domain-specific profile and style guide using the Systems Modeling Language …

Comparison Of Decision Analysis Methods For A Cubesat Propulsion System, Jared L. Pilcher

Theses and Dissertations

Low Earth Orbit (LEO) is becoming an increasingly congested orbital regime. As a result, propulsion systems on CubeSats are becoming a more desirable feature to provide them with collision avoidance capabilities. To date, there have been very few CubeSat launches with a propulsion system on them. Due to the relatively high cost of a propulsion system compared to the budget of small educational organizations, a decision analysis model is needed so that these organizations can make the best decision between whether to purchase a Commercial-Off-The-Shelf (COTS) product or to develop one within the organization. This research applies three decision analysis …

Assessing The Effectiveness Of Afwerx Ability To Influence Regional Participation Rates And Capture Cluster Specific Technological Innovations, Colin M. Sandor

Theses and Dissertations

The 2018 National Defense Strategy (NDS) emphasized capturing innovation through partnerships with non-traditional defense contractors. Furthermore, the NDS outlined the need to rapidly acquire new technologies to maintain a competitive advantage against our adversaries. The AFWERX program is the Air Forces attempt to accomplish these goals. AFWERX seeks to capture innovations occurring within the private sector of the United States by placing itself geographically within top innovation ecosystems. An approach that creates a setting where the Air Force is one of many investors, who benefit from the learning and investments across the entire network. The research within this paper examines …

Operational Carbon Footprint Of The U.S. Water Sector’S Energy Consumption, Louis J. Zib Iii

Theses and Dissertations

Accounting of energy-related GHG emissions in the water sector have largely been conducted at single utilities or cities and rarely at a regional or country scale. In this study, we assess the carbon footprints of operational energy use for 76 wastewater utilities and 64 water utilities across the United States. Additionally, we investigate water-related GHG emissions at a sub-annual scale through three case cities to understand how GHG emissions change at the monthly scale. We estimate the total drinking water and wastewater GHG emissions associated with electricity, biogas, natural gas, and fuel oil consumption across the United States to be …

Cislunar Debris Propagation Following A Catastrophic Spacecraft Mishap, Nathan R. Boone

Theses and Dissertations

This research involves theoretical analysis of the short- and long-term motion of space debris in cislunar trajectories following a spacecraft catastrophic mishap. Specifically, the research formulates a debris propagation model using four-body dynamics and determines debris trajectories following breakup events for a variety of different initial orbital positions. A spacecraft survivability model is then used to quantify the risks from the debris to other cislunar spacecraft. First, a study of the risks due to natural debris comprising the Kordylewski clouds at the Earth-Moon ��₄ and ��₅ Lagrange points is conducted as an introduction to cislunar debris propagation. Next, …

Analysis Of Pollution Prevention Business Case Analyses, Erwin A. Spencer Jr.

Theses and Dissertations

The purpose of this research is to improve the Business Case Analysis (BCA) process in the context of pollution prevention. The research will inform guidance, training, and policy recommendations. Using grounded theory methods allowed us to gather qualitative data directly from participants actively involved in pollution prevention projects. In addition to answering several research questions, the results of the research informed the design of a tool to help government and contractor personnel agree on what constitutes a high-quality BCA. This research has implications for DoD decision making and future studies in environmental cost analysis.

Static Fatigue Of Hi-Nicalon S Fiber Tows At 500°C In Air And In Silicic Acid-Saturated Steam, Richard J. Reinink

Theses and Dissertations

Recent developments in aerospace propulsion systems, along with emerging interest in hypersonic air vehicles has emphasized the need for materials which can withstand extreme service environments. The leading candidates for the structural components expected to operate in these environments are SiC-based ceramic matrix composites (CMCs). When a CMC component is subjected to thermomechanical loads in an aggressive environment during service, surface cracks form. As steam penetrates cracks in the SiC matrix, it becomes saturated with silicic acid, (SI(OH)₄) and attacks the SiC fibers. The interaction between the Hi-Nicalon™ S SiC fibers and the (SI(OH)₄)-saturated steam is …

Applied Reachability Analysis For Time-Optimal Spacecraft Attitude Reorientations, Layne C. Barrett

Theses and Dissertations

Satellite attitude reorientation has been of significant interest in astronautical engineering, and being able to reorient in a time-optimal manner has been of exceeding interest since the 1970s. Ensuring a spacecraft mission set can be conducted within a certain amount of time begs the question of whether or not a certain maneuver can be completed with a bounded control. This thesis answers that question by using the concept of reachability to provide reachable sets for different spacecraft reorientation scenarios. The reachable sets generated provide a range of initial states that guarantee a satellite reach a desired end orientation given a …

Improving Manufacturability And Reducing Cracking In Additively Manufactured Tungsten Alloys, Christopher P. Fassio

Theses and Dissertations

Additively Manufactured tungsten suffers from low () densities due to high concentrations of microcracks as the printed layers cool past tungsten's high ductile to brittle transition temperature. In this study, tungsten-rhenium and tungsten rhenium hafnium carbide compositions were evaluated on density and tensile strength. In addition to varying the compositions of each alloy, printing parameters and post-processing methods were also compared. Print parameters varied for all compositions on an MLab 200R C using included the laser scan strategy, hatch spacing, scan speed, laser power, and print bed material. Post processing techniques of the WRe compositions included hot isostatic pressing and …

Remote Monitoring Of Memory Data Structures For Malware Detection In A Talos Ii Architecture, Robert A. Willburn

Theses and Dissertations

New forms of malware, namely xC;leless malware and rootkits, pose a threat to traditional anti-malware. In particular, Rootkits have the capacity to obscure the present state of memory from the user space of a target machine. If thishappens, anti-malware running in the user space of an axB;ected machine cannot be trusted to operate properly. To combat this threat, this research proposes the remote monitoring of memory from a second, secure processor runningOpenBMC, serving as a baseboard management controller for a POWER9 processor, which is assumed vulnerable to exploitation. The baseboard management controller includes an application called pdbg, used for debugging …

Automated Find Fix And Track With A Medium Altitude Long Endurance Remotely Piloted Aircraft, Aubrey L. Olson

Theses and Dissertations

A limitation in RPA ISR operations is loss of target track if the command link is severed. For an RPA to effectively execute the ISR mission without a command link, it needs the capability to F2T targets autonomously. Automated Find Fix and Track (AFFTRAC) was developed to help solve this problem by demonstrating a proof of concept tactical autopilot. Monocular stereo vision was used to process sequential images acquired during orbit to produce a partial structural point cloud of the original structure. This partial structural point cloud was then exploited to create a holding area density for the aircraft to …

Safe Spacecraft Rendezvous And Proximity Operations Via Reachability Analysis, Paul A. Grossi

Theses and Dissertations

The rapid expansion of the utilization of space by nations and industry has presented new challenges and opportunities to operate efficiently and responsibly. Reachability analysis is the process of computing the set of states that can be reached given all admissible controls and can be a valuable component in an autonomous mission planning system if conducted efficiently. In the current research, reachability analysis is used with several relative motion models to show that all ranges of orbits can be computed in milliseconds, and that it is a feasible approach for on-board autonomous mission planning. Reachability analysis is then combined with …

Fatigue Of Two Oxide/Oxide Ceramic Matrix Composites At 1200°C In Air And In Steam. Effect Of Diamond Drilled Effusion Holes, Anthony R. Cabri

Theses and Dissertations

The tension-tension fatigue behavior of two oxide-oxide ceramic matrix composites (CMCs) was investigated at 1200°C in laboratory air and steam. Both composites consist of a porous oxide matrix reinforced with laminated, woven mullite/alumina (NextelTM720) fibers. The first composite had an alumina matrix, while the second had an alumina-mullite matrix. First, we assessed the effects of incorporating mullite into the matrix material on fatigue performance by studying the tension-tension fatigue behavior of alumina-mullite matrix CMC. Second, we evaluated the effects of effusion holes on the alumina matrix CMC's fatigue performance. Specimens containing an array of 17 effusion holes of 0.5-mm diameter …

Using Motion Capture And Augmented Reality To Test Aar With Boom Occlusion, Vincent J. Bownes

Theses and Dissertations

The operational capability of drones is limited by their inability to perform aerial refueling. This can be overcome by automating the process with a computer vision solution. Previous work has demonstrated the feasibility of automated aerial refueling (AAR) in simulation. To progress this technique to the real world, this thesis conducts experiments using real images of a physical aircraft replica and a motion capture system for truth data. It also compares the error between the real and virtual experiments to validate the fidelity of the simulation. Results indicate that the current technique is effective on real images and that the …

Evaluation Of Efficient Water Reuse Technologies For Sustainable Forward Operating Bases, Kelsie L. Crouch

Theses and Dissertations

A secure water source is essential to the resiliency and readiness of military installations and contingency operation locations, especially those located in the dry climates the US military operates in today. There are multiple issues of concern when identifying water sources, such as security, cleanliness, accessibility, and sustainability. Water resources pose a potential vulnerability to mission readiness in a remote, agile environment, such as a forward operating base (FOB). Having a secure water resource helps facilitate mission readiness in the contingency environment, offering the opportunity to be more resilient and cost-effective. Current water treatment technologies present the possibility to perform …

Climate-Informed Prediction And Forecast Modeling Of Installation Total Energy Consumption, Scott C. Weiss

Theses and Dissertations

Climate variability is an external and stochastic factor that causes energy demand uncertainty. Energy managers can use climate-based models to understand future trends of energy demand and to adjust operations, policy, and budgets accordingly. This research focuses on 1) identifying how climate attributes impact energy use, 2) creating a historically informed statistical modeling framework to skillfully predict energy use, and 3) forecasting future changes to energy use and costs, using CMIP5 temperature projections, at the campus level. After synthesizing the existing breadth of research on climate-informed energy modeling, a skillful, unbiased, climate-informed total energy consumption prediction model is developed for …

Studying The Conditions For Magnetic Reconnection In Solar Flares With And Without Precursor Flares, Seth H. Garland

Theses and Dissertations

Forecasting of solar flares remains a challenge due to the limited understanding of the triggering mechanisms associated with magnetic reconnection, the primary physical phenomenon connected to these events. Consequently, methods continue to rely on the climatology of solar flare events as opposed to the underlying physics principles. Models of magnetic reconnection in the solar atmosphere places the null point of the reconnection within the corona. Though as of now the coronal magnetic field cannot be directly measured, the field is tied to the photospheric magnetic field, which can be. This study utilized data from the Solar Dynamics Observatory Helioseismic and …

Impendance Probe Payload Development For Space-Based Joint Service Collaboration, Brian T. Kay

Theses and Dissertations

Collaborations utilizing small spacecraft in near earth orbit between the U. S. Coast Guard Academy (CGA), Naval Research Lab (NRL), the U. S. Naval Academy (USNA), and the Air Force Institute of Technology (AFIT) have initiated scientific and engineering space-based experiments. Sourced opportunities like the VaSpace ThinSat missions have provided a platform for payload, sensor, and experiment development that would have otherwise been resource prohibitive. We have constructed an impedance probe payload derived from the existing ‘Space PlasmA Diagnostic suitE’ (SPADE) mission operating from NASA’s International Space Station. Currently both space and laboratory plasmas are investigated with AC impedance measurements …

Best Practices For Bridge Crane Implementation And Installation: A Case Study, Sterling D. Treloar

Construction Management

Overhead Cranes, which are more commonly referred to as bridge cranes, provide a substantial amount of flexibility with respect to the user’s ability to move material and heavy equipment throughout a factory or manufacturing facility. Oftentimes, the client is not aware of the benefits of implementing bridge cranes rather than using mobile gantry cranes. The client may not be aware of the benefits of bridge crane installation occurring at the beginning of a project or in fact, including it in the initial design of the project, rather than considering it in the middle of the project. This case study will …

Field Welding Repair Of Heavy Equipment, Phil Akahori

Construction Management

Welding repairs of heavy equipment in the field can vary in levels of success. This can be due to the high strength steels used in the manufacture of heavy equipment implements that require special metallurgical considerations. Repair difficulties can be further compounded by the limitations of tooling typically found on a construction site and schedule commitments. Overloading or excessive impacts can cause damage to the bucket teeth of an excavator or bulldozer rippers. A shop could perform a proper repair but that increases cost and takes precious time. A successful repair of these items done out in the field can …

Schedule Efficiency Associated With The Tilt-Up Construction Method: A Case Study, Jake A. Barron

Construction Management

Tilt-up is an efficient method of project delivery that is best suited for large, flat projects such as commercial warehouses and distribution centers. The hypothesis is that this method of casting wall panels on site, and then tilting them upright, allows for certain unique activity sequences which could provide faster project completion. In order to prove this theory, analysis of two tilt-up projects completed within a mile of each other by the same contractor, and assessment of their schedules, will provide insight into the specific tasks that allow for better delivery speed. This methodology paired with interviews of team members, …

The Pacific Sentinel: March/April 2021, Mini Issue, Portland State University. Student Publications Board

The Pacific Sentinel

Editor: Vivian Veidt

Articles in this issue include:

• Letter From the Editor
• Royalty Notwithstanding
• A Man, a Plan, and a Virus
• United We Stand?
• Dreamhouse and Other Horrors
• The Art of the Podcast

Mape-R: A Rescaled Measure Of Accuracy For Cross-Sectional Subnational Population Forecasts, David Swanson, Jeff Tayman, T. M. Bryan

Publications, Reports and Presentations

Accurately measuring a population and its attributes at past, present, and future points in time has been of great interest to demographers. Within discussions of forecast accuracy, demographers have often been criticized for their inaccurate prognostications of the future. Discussions of methods and data are usually at the centre of these criticisms, along with suggestions for providing an idea of forecast uncertainty. The measures used to evaluate the accuracy of forecasts also have received attention and while accuracy is not the only criterion advocated for evaluating demographic forecasts, it is generally acknowledged to be the most important. In this paper, …

Drinking To Cope In The Covid-19 Era: An Investigation Among College Students., Cynthia D. Mohr, Sheila K. Umemoto, Thomas W. Rounds, Philip Bouleh, Sarah N. Arpin

Psychology Faculty Publications and Presentations

The COVID-19 pandemic has resulted in abrupt, drastic changes to daily life in many nations. Experiences within the United States have varied widely. In the State of Oregon in the early months of the pandemic protective protocols (e.g., social distancing) were comparatively high, resulting in concern for increases in loneliness and COVID-related stress. The present study of college students examined the indirect relationship of loneliness and other stressors to alcohol use, via drinking-to-cope motives.

Bi-Objective Optimization For Battery Electric Bus Deployment Considering Cost And Environmental Equity, Xiaoyue Cathy Liu, Yirong Zhou, Ran Wei, Aaron Golub, Devin Macarthur

TREC Final Reports

Public transit, compared with passenger cars, can effectively help conserve energy, reduce air pollution, and optimize flow on roadways. In recent years, Battery Electric Bus (BEB) is receiving an increasing amount of attention from the transit vehicle industry and transit agencies due to recent advances in battery technologies and the direct environmental benefits it can offer (e.g., zero emissions, less noise). However, limited efforts have been attempted on the effective deployment planning of the BEB system due to the unique spatiotemporal features associated with the system itself (e.g., driving range, bus scheduling). In this project, we developed an innovative spatiotemporal …

Transit Impacts On Jobs, People And Real Estate, Arthur C. Nelson, Robert Hibberd, Kristina Marie Currans, Nicole Iroz-Elardo

TREC Final Reports

This is the first volume of a five-volume set of publications comprising the report titled “Transit Impacts on Jobs, People and Real Estate.” It is the culmination of four research projects funded by the the National Institute of Transportation and Communities (NITC), a US DOT funded National University Transportation Center. This volume includes a preface that review key findings of the prior four research grants, an executive summary that reviews key findings of all five volumes of the current report, the context that reviews the context of the present research including details on more than 50 fixed route transit systems …