Digital Commons Network^™

Distributed Control Of Servicing Satellite Fleet Using Horizon Simulation Framework, Scott Plantenga

Master's Theses

On-orbit satellite servicing is critical to maximizing space utilization and sustainability and is of growing interest for commercial, civil, and defense applications. Reliance on astronauts or anchored robotic arms for the servicing of next-generation large, complex space structures operating beyond Low Earth Orbit is impractical. Substantial literature has investigated the mission design and analysis of robotic servicing missions that utilize a single servicing satellite to approach and service a single target satellite. This motivates the present research to investigate a fleet of servicing satellites performing several operations for a large, central space structure.

This research leverages a distributed control approach, …

Play Area Utilization Optimization For Room-Scale Exploration Of Virtual Worlds, Chase Vanderzwan

Master's Theses

Virtual Reality (VR) opens up new possibilities for developers to create immersive worlds and experiences. While it’s possible to craft unique and engaging interactive environments with unprecedented realism, the virtual world is constrained by the real one. Current approaches to player navigation in VR applications include joystick controls, teleportation, and motion-based movement. While these methods are effective in certain scenarios to overcome real-world limitations, my research introduces a novel approach that leverages room scale-based movement, with portals, to traverse a given VR world. This work presents algorithms that accurately predict the percentage of play area utilized, and rules to implement …

Analyzing Robustness Of An Agent Based Model On Action Potentials In Cardiac Tissue, Marion Jon Zollinger Lara

Master's Theses

An agent based model (ABM) is a computational model with ``agents'' that interact with each other in an ``environment.'' This paper analyzes a particular ABM simulating individual ions in cardiac tissue, with the goal of modelling the strength and consistency of the electrical signals needed for a healthy heartbeat. We build several frameworks based on work by M. A. Yereniuk and S. D. Olson to demonstrate robustness of the original model. We conclude a moderate level of robustness using those frameworks, through a combination of proofs and empirical evidence.

Implementation Of Topology Optimization Into The Mechanical Design Process, Nolan Clapp

Master's Theses

Topology Optimization is a lightweighting method based on finite element analysis that produces a part with optimum material distribution in the design space. Results from topology optimization often have organic shapes and curves that are difficult if not impossible to machine with traditional subtractive manufacturing methods. This paper analyzes the implementation of the Solidworks® Topology Optimization add-in into the mechanical design process and discusses required postprocessing to ensure manufacturability of the optimized part though a case study on two example parts. Results of traditional optimization, topology optimization and “selective” optimization (optimization using the results from topology optimization to selectively remove …

Effects Of Intertidal Position On The Response To Oxygen And Desiccation Stress In The Common Acorn Barnacle, Balanus Glandula, Megan M. Dotterweich

Master's Theses

Sessile invertebrates in the rocky intertidal experience intermittent periods of air exposure due to tidal flux, presenting risks of temperature extremes, hypoxia, nutrient limitation, and most dangerously, desiccation. Microscale variation in severity and frequency of these risks is widely dependent on vertical position within the intertidal zone. Common acorn barnacles (Balanus glandula) have a wide vertical distribution in the intertidal, creating large differences in microhabitat between the highest and lowest individuals in the population. This study set out to explore whether tidal position dependent differences exist in the response to oxygen and desiccation stress in B. glandula. …

Development Of Wiskott-Aldrich Syndrome Knock Out Protocol For Drug Substance Assay Development, Julia C. Hanna

Master's Theses

Wiskott-Aldrich Syndrome (WAS) is a rare X-linked primary immunodeficiency affecting approximately 1 in 100,000 live XY births in North America and is caused by a mutation to the WAS gene which is expressed across hematopoietic lineages. The WAS protein (WASp) plays a role in regulating actin polymerization. On a cellular level, there are a variety of effects of a lack of WASp or expression of a dysfunctional WASp protein for patients including issues with migration, adhesion, chemotactic response, phagocytosis, activation, and proliferation across different cell types in addition to reduced platelet size and output. This can lead to several systematic …

Deep Learning Recommendations For The Acl2 Interactive Theorem Prover, Robert K. Thompson, Robert K. Thompson

Master's Theses

Due to the difficulty of obtaining formal proofs, there is increasing interest in partially or completely automating proof search in interactive theorem provers. Despite being a theorem prover with an active community and plentiful corpus of 170,000+ theorems, no deep learning system currently exists to help automate theorem proving in ACL2. We have developed a machine learning system that generates recommendations to automatically complete proofs. We show that our system benefits from the copy mechanism introduced in the context of program repair. We make our system directly accessible from within ACL2 and use this interface to evaluate our system in …

Examining The Use Of A Network Bypass To Circumvent Data Diodes Within Industrial Control Systems, Bryce Molesh

Master's Theses

Our modern world relies upon large scale industrial plants, that are manged by Industrial Control Systems (ICS), to provide critical services such as electricity, water, or waste processing. Over time, these systems have been increasingly connecting outdated systems to modern internet technology to provide additional functionality such as real-time monitoring while also enabling operators to conduct modern business analytics. Thus, these plants offer a potential target for attackers. Recently, such attacks on Industrial Control Systems have increased in number with well publicized attacks such as Stuxnet and TRISIS. To protect against such attacks while also modernizing their networks, Industrial Control …

An Empirical Evaluation Of Neural Process Meta-Learners For Financial Forecasting, Kevin G. Patel

Master's Theses

Challenges of financial forecasting, such as a dearth of independent samples and non- stationary underlying process, limit the relevance of conventional machine learning towards financial forecasting. Meta-learning approaches alleviate some of these is- sues by allowing the model to generalize across unrelated or loosely related tasks with few observations per task. The neural process family achieves this by con- ditioning forecasts based on a supplied context set at test time. Despite promise, meta-learning approaches remain underutilized in finance. To our knowledge, ours is the first application of neural processes to realized volatility (RV) forecasting and financial forecasting in general.

We …

Groups Of Non Positive Curvature And The Word Problem, Zoe Nepsa

Master's Theses

Given a group $\Gamma$ with presentation $\relgroup{\scr{\scr{A}}}{\scr{R}}$, a natural question, known as the word problem, is how does one decide whether or not two words in the free group, $F(\scr{\scr{A}})$, represent the same element in $\Gamma$. In this thesis, we study certain aspects of geometric group theory, especially ideas published by Gromov in the late 1980's. We show there exists a quasi-isometry between the group equipped with the word metric, and the space it acts on. Then, we develop the notion of a CAT(0) space and study groups which act properly and cocompactly by isometries on these spaces, such groups …

Documenting Tetranychus Urticae And Lygus Hesperus Resistance Status In California Strawberries, Kiley William Jensen

Master's Theses

The resistance status of Tetranychus urticae Koch and Lygus hesperus Knight sourced from California strawberry fields was evaluated in laboratory bioassay experiments. Adult female T. urticae sourced from a miticide naïve population were exposed to a range of miticide active ingredient concentrations mixed with acetone in contact bioassay experiments. LC₅₀ concentrations for the active ingredients fenpyroximate, abamectin, bifenazate, and spiromesifen as well as LC₉₀ concentrations for the active ingredients fenpyroximate, abamectin, and bifenazate were derived from this susceptible population. A total of ten field populations of T. urticae, five from the Santa Maria growing region and five …

Coupled Boundary Conditions For Modeling Airbreathing Engines, Adam Louis Waldemarson

Master's Theses

Modeling the flight conditions of an aircraft that utilizes an airbreathing propulsion system necessitates a method to account for the increase in energy introduced into the flow. Current methods for modeling engines either assign fixed conditions on flat faces on the intake and exhaust through a manual process with the use of external models or attempt to model the flow through the engine within the simulation using complex and computationally expensive geometry and solvers. The method presented attempts to provide an intermediate option to model airbreathing engines through coupling the intake and exhaust boundary conditions with a parametric engine model. …

​ Soilborne Pathogens Of Strawberry In The Central Coast Region Of California: ​ Survey And Cover Cropping With Wheat For Management Of Macrophomina Phaseolina, Mary Steele

Master's Theses

Surveys of the four major soilborne pathogens of strawberry (Fusarium oxysporum f. sp. fragariae, Macrophomina phaseolina, Phytophthora spp., and Verticillium dahliae) to determine their relative prevalence were conducted in Watsonville-Salinas, CA in 2021 and in Santa Maria, CA in 2022. All four major pathogens were detected at relatively similar prevalence in Watsonville-Salinas, between 22% and 31% of sampled fields. In Santa Maria, M. phaseolina was far more prevalent at 52% of sampled fields, the other three falling between 14% and 17%. Additionally replicated greenhouse and field trials were conducted to evaluate the effects of wheat as …

Refactoring Dependency Loading And Standardizing Factory Patterns In The Horizon Simulation Framework, Jack W. Kelly

Master's Theses

The Horizon Simulation Framework (HSF) is an open-source community driven mod- eling and simulation tool developed over 15 years by a lineage of Cal Poly graduate students. The tool excels in its flexibility to model an assortment of complex systems, with prebuilt modeling elements available for the simulation of space missions. A high-level simulation tool like HSF lends itself to an agile development cycle as system constraints can be quickly identified through day in the life simulation of the modeled system. The objective of the work presented in this thesis is to refactor the way in which several modeling elements …

Effects Of Concussion And Visuomotor Metrics On Nhl Performance: An Explainable Ai Approach, Michael T. Moschitto

Master's Theses

Cognitive motor integration (CMI), the simultaneous coordination between cerebral function and motor output, is known to deteriorate following a mild traumatic brain injury (mTBI). This thesis explores the relationship between mTBI, CMI, and the performance of elite athletes in the National Hockey League (NHL). The approach focuses on examining the predictive value of various supervised Machine Learning (ML) models with an emphasis on Explainable Artificial Intelligence (XAI) models. Since the ML solution is intended to complement human scouting decisions, we evaluate the experiments based on both interpretability and accuracy on a limited class imbalanced dataset. The contributions of this research …

Solving Supersonic Flows Using The Method Of Integral Relations In Python, Eddie Hsieh

Master's Theses

This thesis presents a modern approach to the Method of Integral Relations implemented in the Python programming language. This work is based on South's reports on solving supersonic conical flows and Belotserkovskii's publications on solving supersonic flows over blunt bodies. The Python SciPy library is extensively used in this thesis. A root finder module is used to perform South's solution process, and the Runge-Kutta ODE solver with dense output is implemented to replicate Belotserkovskii's solution process. The implementation of Python makes the development efficient and serves as an open-source framework for future work to build on. This work focuses on …

Range-Doppler Map Processing Chain For Marine Radar On Fpga Of An Rfsoc, Nickolas W. Ogilvie

Master's Theses

To improve the accuracy and resolution of the measurements, radar systems employ increasingly complex, resource-intensive signal processing, larger bandwidths, and higher carrier frequencies. However, implementing these improvements requires more expensive, complex electronics that are larger and use more power. Using RFSoC (Radio Frequency System on Chips) in radars can address these challenges. By combining processors, an FPGA (Field Programmable Gate Array), and RF data converters into a single integrated circuit, RFSoCs allow for radar electronics that are physically smaller, use less power, and are simpler to design. As using RFSoCs to perform RF data conversion for radars has been already …

Implementation Of Log4net And Parametric Modeling Within The Horizon Simulation Framework, Evan Andrew Droz

Master's Theses

Creating system models and simulations allow for rapid, iterative analysis of spacecraft mission performance. This design methodology provides opportunities for improvement before allocating resources towards further physical spacecraft development. Horizon Simulation Framework (HSF) is a system evaluation tool that can be used for the assessment of spacecraft mission performance, subject to mission targets, constraints, and spacecraft design. Specific subsystems are defined for a unique mission case and are evaluated through a Day-in-the-Life (DITL) scenario simulation. Valuable information can be derived from failed attempted mission-related events, highlighting shortcomings in subsystem capabilities. Further information can be unveiled by assessing possible system sensitivity …

Design And Implementation Of A Prototype Pendulum Platform For Aerospace Controls Education, Zachary A. Wright

Master's Theses

This thesis presents a modular, low-cost, prototype inverted pendulum platform for undergraduate Aerospace control theory research and education. The platform's default configuration integrates a propeller and reaction wheel as its actuators, with multiple sensors available to measure the pendulum's states. The platform utilizes open-source software and hardware to power the actuators, and uses MATLAB/Simulink to streamline data collection. System identification techniques are applied to the platform, and the mathematical model of the pendulum is verified. Momentum exchange between the reaction wheel and propeller during closed-loop stabilization of the pendulum is demonstrated.

Composite Solid Rocket Motor Case Optimization With Matlab Genetic Algorithm, Aleksandr Breit

Master's Theses

This study utilizes MATLAB genetic algorithm (GA) to perform optimization on a solid rocket motor (SRM) chamber structure. The (SRM) structure is modelled as a cylindrical composite laminate where unidirectional fiber orientations are the primary design variable in the optimization problem formulation. Additional design variables such as chamber length, diameter, and internal pressure are altered along with the ply angles to minimize the safety margin towards a near-zero value and encourage efficient layup design. Classical lamination theory with Tsai-Wu failure criterion are used to calculate ply-level safety margins. A thickness minimization scheme is employed to reduce the ply count from …

Reconstructing Identity: Carlton Burgan, Patient Zero In The Development Of Plastic Surgery, Civil War Through World War I, Teresa M. George

Master's Theses

Plastic surgery has played an integral role in helping people achieve societal expectations of appropriate physical appearance since its inception. Through the story of Carlton Burgan, a Union soldier during the American Civil War, who suffered severe facial trauma by mercury poisoning, this thesis hopes to reconstruct the conversation around plastic surgery’s origins as it is influenced by societal standards of the day. Specifically, this thesis argues that the seminal moments leading to plastic surgery being seen as a worthwhile medical specialty was during the Civil War, not World War I as so many scholars have put forth. Violent acts …

Marine Protected Areas And Oceanographic Variability: Impacts On Blue Rockfish (Sebastes Mystinus) And The Human Dimensions Of Collaborative Fisheries Research, Erin M. Johnston

Master's Theses

Fishing pressure and environmental variability are two of the most impactful drivers of fish populations worldwide. It is critical to effective management to understand the intersection between the two and how each may affect fish population dynamics, especially for exploited nearshore species like rockfishes (Sebastes spp.). This is especially true as models indicate that global climate change will dramatically increase the frequency and severity of large-scale oceanographic perturbations. We were interested in whether we could detect changes in relative abundance of nearshore rockfishes relative to large-scale oceanographic events using a broad-scale index like the Multivariate Ocean Climate Indicator …

Assessing Dynamics And Trends Of Co2 Flux On The Louisiana Shelf, Claire Mcguire

Master's Theses

The Gulf of Mexico on an annual timescale acts as a sink for ­CO₂. Previous studies have investigated regional-scale trends in the Gulf based on model output. In our investigation of the northern Gulf of Mexico, and especially the area surrounding the Louisiana delta, we found different trends compared with previous studies of the open ocean Gulf and broader shelf region. Predictions of global patterns of the ocean CO₂ cycle require regional studies of unique areas like the Louisiana Shelf. The Louisiana Shelf is a shallow system, has input from river systems, experiences seasonal hypoxia, and is …

Understanding The Flow Dynamics Of The Pearl River, Ms, Through Hydrodynamic Modeling, Nahruma Mehzabeen Pieu

Master's Theses

The Pearl River brings fresh water and nutrients into Lake Borgne regulating conditions for oyster growth in estuarine waters. However, there are no flow measurement stations installed on East Pearl or West Pearl either at the river outlets or after the upstream bifurcation of the Pearl. This study aims to model the Lower Pearl River to understand the flow dynamics in the major branches, and to determine the final outflow distribution into the Mississippi Sound, aiming to improve river forcing for ocean models studying estuarine dynamics of the Mississippi Sound.

Synthetic meandering bathymetry with updated banks is developed and applied …

Predictive Ability Of A 3d Body Scanning Mobile Application For Metabolic Health Risk, Caleb Brandner

Master's Theses

There is an increasing prevalence of obesity within the US and rising rates of metabolic syndrome among those aged 20-39 concurrent with a decrease in the reception of primary care. Limitations to healthcare including access, cost, and availability, highlighting the need for simple, efficient, and accessible cardiometabolic health risk screening. Given the surge in smartphone ownership over the last decade, this study sought to determine the predictive ability of a mobile 3D-optical (3DO) body composition assessment application in determining metabolic health risk. A total of 62 participants (female: 36) underwent traditional anthropometric measurements, 3DO body scanning using a smartphone application, …

Estimation Of Quantitative Genetic Parameters Of The Eastern Oyster (Crassostrea Virginica) In The Gulf Of Mexico, Heather King

Master's Theses

The decline of natural oyster reefs in Gulf of Mexico (Gulf) states has stimulated the development of aquaculture to support the industry and restoration programs. Gulf habitats feature diverse salinity environments that may require oysters bred for habitat-specific optimal genetic characteristics. In this work, genetic parameters for performance in habitats with different salinity were estimated. In September 2020, 102 males and 102 females sourced from 17 natural reefs across the northern Gulf were bred according to 2 males x 2 females non-overlapping factorial crossing designs, resulting in 204 full and half sibs. All families were pooled after fertilization according to …

A Minor Place: A Short Story Collection, Nathaniel Pyle

Master's Theses

In this collection, characters often face interior struggles such as past lives, abusive upbringings, dead partners, and relationship struggles. A Minor Place concerns loneliness and existentialism set with a melancholy, southern gothic setting. Characters toil with their psychological state within a shared and collective universe of the unknown. The characters found within A Minor Place deal with sensitive issues such as loss, isolation, and overcoming their difficulties. A Minor Place implements narratives to showcase a "minor” tonality and coloration and style to accompany this titular minor place.

Agricultural Shocks On Household Stability: A Case Study Of Tanzania Maize Farmers, Zimmi Silonda Ndlovu

Master's Theses

As the global populations grow, the need for stronger agricultural resilience in areas with high food insecurity like Sub-Saharan Africa (SSA) is a must. Crop failure due to climate related events has increased substantially over the past decade, raising the risks to vulnerable groups like subsistence farmers. Understanding the effects of climate variability on farmers and their crops is a pivotal step towards increasing resilience and productivity. In this paper I approach this question using a Linear Probability Fixed-effects Model on Tanzanian Panel Survey data with monthly temperature and precipitation for years 2008 to 2013. Results suggest a negative relationship …

War And Genocide In Darfur And Its Impact On Darfur Society, Hamid Elshareif

Master's Theses

The Darfur region in western Sudan has witnessed bloody revolutions and conflicts since the beginning of 2003. The Sudanese government recruited militias such as Janjaweed who killed and robbed the civilian people of Darfur. The Janjaweed practiced murder, rape, torture, the burning of villages, looting, and theft which amounted to what most people consider genocide. This genocide is being practiced against the indigenous African tribes in the western region of Sudan which is less developed and has been marginalized by the government in Khartoum. Reasons for this conflict are in question with many people seeing it as purely an Arab …

'Formation In Distinctive Dimensions Of Our Way Of Proceeding': Preparation Of Lay Directors Of Works In Jesuit Schools, Perry T. Petrich Sj

Master's Theses

The purpose of the study was to determine how lay directors of works in Jesuits West secondary schools can be formed to best serve as faith leaders. The study consisted of secondary research in which interview data and surveys from studies on lay formation in Jesuit universities and lay leadership of Bay Area Catholic High Schools were used to determine whether or not formation of lay directors of works in faith leadership is possible, what the objectives of that training should be, and how that training can be offered. This analysis determined that lay formation is both possible and necessary. …