Engineering Commons^™

Data-Driven Physical-Layer Optimization For Rf And Optical Communications: Transmitarray Metasurfaces, Contextual-Bandit Mud, And Coherent Optical Links, Chengtao M. Xu

Doctoral Dissertations and Master's Theses

This dissertation studies three physical-layer optimization problems that share a common difficulty: the forward model, whether an electromagnetic solver or a statistical channel model, is either too expensive to evaluate at design scale or too unstable to hold across a single processing block. The first two problems are treated in their own right, as problems in antenna design and in multi-user detection over time-variant channels; the third carries the methodology onto a coherent optical link, where size, weight, and power constraints make a small-satellite deployment the natural target.

The antenna work targets a tri-layer pixelated unit cell fabricated on Avient …

Contributions To Ship-Airwake-Rotor Coupling Characterization Using Controlled Forcing, Guillermo Mazzilli

Doctoral Dissertations and Master's Theses

Shipboard helicopter operations occur within a highly unsteady environment referred to as the dynamic interface (DI), encompassing the coupled effects of the ship airwake, rotor wake, flight dynamics, and pilot response. A central aspect of the DI is the aerodynamic interaction between the ship airwake and the rotor wake, which degrades handling qualities and increases pilot workload, yet the underlying mechanisms governing ship-rotor coupling remain insufficiently understood. The ship-rotor aerodynamic coupling was examined using two canonical ship geometries, the NATO-GD and SFS2, together with a controlled experimental framework, the airflow-and-blade-frequency (ABF) system, which independently varied wake momentum flux and unsteady …

From Reactive To Predictive: A Hybrid Trust-Mediated Adoption Framework For Data-Driven Maintenance In Distributed-Authority Aviation Environments, Dustin J. Foote

International Journal of Aviation, Aeronautics, and Aerospace

Modern aviation maintenance operates within increasingly data-intensive technological environments, yet the operational integration of predictive maintenance into routine decision-making remains inconsistent across sectors. Contemporary aircraft incorporate centralized maintenance computers and condition monitoring architectures capable of fault aggregation, exceedance capture, and trend-based data collection. Although prognostics and health management research continues to advance detection and prediction methods, implementation outcomes often depend on factors beyond analytical performance alone.

This paper examines predictive maintenance adoption in distributed-authority aviation environments and argues that constraints emerge less from sensing capability than from organizational structure, decision authority dispersion, and institutional trust dynamics. For purposes of analysis, …

Digital Twin–Oriented Certification Architecture For Advanced Air Mobility, Daniel Pleffken

International Journal of Aviation, Aeronautics, and Aerospace

Advanced Air Mobility (AAM) systems introduce certification challenges associated with distributed propulsion, increasing software reliance, and tightly coupled architectures. These characteristics evolve within regulatory environments that are still adapting to emerging vehicle concepts. While digital engineering practices are increasingly adopted during system development, certification workflows remain largely document-centric, limiting lifecycle traceability and consistent reasoning about change impacts as designs and regulatory interpretations evolve. This paper proposes a Digital Twin–oriented certification architecture that integrates regulatory knowledge, system representations, Means of Compliance (MoCs), and verification artifacts within a unified model-based environment. The architecture is organized around four elements: regulatory structuring, Model-Based Systems …

Clear-Air Turbulence Climatology And Trends, Liam Rodgers, Mark Sinclair

Publications

Clear‑air turbulence (CAT) is a major aviation hazard that occurs near airline cruising altitudes in both cloud and cloud‑free environments. Its lack of a distinct visual signature makes detection and avoidance difficult. CAT is associated with wind shear near jet streams, gravity waves, and Kelvin–Helmholtz instability and may be further enhanced by climate change. This study examines the climatology, spatial distribution, seasonal variability, and trends of CAT over the contiguous United States.

Pilot Reports (PIREPs) from 2001–2025 between 100 and 400 hPa are analyzed alongside jet stream, shear, and stability diagnostics derived from NCEP–NCAR Reanalysis data. Proxies such as inverse …

Thermoacoustic Effects Of A Variable Equivalence Ratio In A Single Element Methane Combustor, Carter Green

Doctoral Dissertations and Master's Theses

Combustion instability is one of the leading factors in limiting the progress and innovations of liquid rocket engines and power plants. Under certain operating conditions, unsteady heat release and acoustic wave interactions can couple and lead to instabilities, such as self-sustaining pressure oscillations, that can lead to reduced combustor performance and potentially hardware damage. In this project, the thermoacoustic effects of controlling the equivalence ratio of a single-element natural gas combustor were modeled and analyzed. The project used Fidelity Pointwise for meshing, ANSYS Fluent for modeling, ERAU VEGA HPC for computing, and MATLAB for acoustic analysis. A numerical model of …

Threat-Analysis Oriented Digital Twinning Of Ml-Powered Future Autonomous Weapon Systems, Thomas Neubert

Doctoral Dissertations and Master's Theses

Warfare is undergoing a rapid transformation with the integration of artificial intelligence (AI) and machine learning (ML) into autonomous weapon systems (AWS) for perception, decision support, and control. As these systems become more software-defined, their cyber attack surface expands across sensing, communications, autonomy logic, and human-machine interfaces. As human oversight diminishes, ensuring the cybersecurity, resilience, and reliability of these systems becomes critical to mission success. This thesis investigates how a digital twin-driven threat modeling framework that integrates system-centric analysis with adversary-informed methodologies can support structured cybersecurity vulnerability evaluation and defensive strategy development associated with ML-powered AWS. First, the study analyzes …

Numerical Study Of Nutrient Mixing In Trabecular Bone In Microgravity, Disuse And Normogravity, Sagar Gharti

Doctoral Dissertations and Master's Theses

Mechanical loading is known to regulate bone remodeling by driving interstitial fluid flow which stimulates cells and drives nutrient transport within the trabecular network. In microgravity, the absence of mechanical stimulation or loading suppresses convective flow processes, causing diffusion-driven nutrient mixing and renewal, and accelerated bone loss. This thesis investigates how oscillation frequency and trabecular bone density jointly control nutrient mixing and wall shear stress within trabecular cavities.

A computational fluid dynamics (CFD) framework is developed in STAR-CCM+ using a soft-cap oscillation model that mimics cyclic compression. Three idealized trabecular morphologies are simulated across different frequencies to represent microgravity or …

Instrumentation And Control Of A Novel Device To Simulate A Hypersonic Environment, Andrew Marcello

Doctoral Dissertations and Master's Theses

The hypersonic flow regime poses several challenges regarding the design of hypersonic vehicles. Among them is the massive energy and economic expense associated with ground- testing evaluation of material responses within this extreme environment. In order to provide a low-cost, rapid option for preliminary material analysis within hypersonic applications, a novel device is under production to replicate this environment on the surface of these materials. This device has been designed to work in conjunction with Argonne National Laboratory (ANL) Advanced Photo Source (APS) synchrotron, to allow for in-situ characterization of ablation and oxidation on the sample surface.

To achieve this, …

Numerical Investigation Of Rotor-Gust Acoustic Interactions Using The Overflow Cfd Solver, Jordan Mills

Doctoral Dissertations and Master's Theses

The rapid expansion of Urban Air Mobility (UAM) necessitates high-fidelity modeling to predict and mitigate the noise signatures of electric vertical take-off and landing (eVTOL) aircraft within dense urban landscapes. A critical unknown in community-noise certification is the aeroacoustic response of rotors to unsteady inflow conditions. This research addresses this gap by investigating the aerodynamic and acoustic behavior of a representative rotor subjected to time-harmonic inflow disturbances. By establishing a robust numerical framework, this thesis quantifies the relationship between periodic atmospheric gusts and their impact on rotor performance, unsteady blade loading, and subsequent sound radiation. The research consists of a …

Insect Inspired Behavioral Strategies For Improving Multi-Agent System Resilience In The Presence Of Contagious Faults, James E. Hand

Doctoral Dissertations and Master's Theses

As Multi-Agent Systems (MASs) become increasingly involved in every aspect of everyday life the need to maintain reliability and resilience within these systems grows. However, in equal measure bad actors wishing to maliciously control or alter these systems are growing in both scale and capability. Thus, there is a present need for control schemes and agent behaviors that provide security against these threats while also avoiding large degradation in system performance as a tradeoff. Current research has covered a wide breadth of avenues and strategies that provide measurable resilience to faulted agents. However, these strategies often require group consensus, specialized …

Ellie - Exteroceptive Light Locomotion In Eukaryote-Fungi, Brandon Etwarroo

Doctoral Dissertations and Master's Theses

Over the past decade, fungal research and its technological applications have expanded across multiple disciplines, including the emerging field of biohybrid systems. This thesis develops and evaluates a wireless, untethered mobile robot controlled by the action potential-like activity generated by Pleurotus ostreatus sporocarps under red, green, and blue optical stimulation. Light is applied to the sporocarps, the resulting electrical responses are recorded, and these signals are transmitted wirelessly to actuate the mobile robot. Both the action potential-like activity patterns and the robot’s movement trajectories were analyzed. The results demonstrate that wireless robotic control mediated by fungal electrophysiology is feasible. Overall, …

Effect Of Nozzle Pressure Ratio On Thrust And Flow Behavior In A Supersonic De Laval Nozzle, Esha Jain

Doctoral Dissertations and Master's Theses

Supersonic nozzles operate across a range of flow regimes. While an ideally expanded condition yields optimal thrust, practical propulsion systems rarely operate at this design point due to variations in altitude and engine operating conditions. As a result, nozzles frequently operate in off-design conditions. In overexpanded regime, where the exit pressure is lower than the ambient pressure, shock-induced separation may occur within the divergent section of the nozzle, potentially degrading nozzle performance. Understanding the aerodynamic behavior of nozzles operating under off-design conditions is therefore important for improving propulsion system performance and stability. In particular, direct thrust measurements provide a key …

Intelligent Flight Control Systems Using Adaptive Deep Neural Networks And Concurrent Learning-Based Design Methods, Maddox C. Morrison

Doctoral Dissertations and Master's Theses

This thesis investigates deep neural network (DNN)-based adaptive control strategies for unmanned aerial vehicles (UAVs) operating under aerodynamic uncertainty and complex actuator dynamics.

The first contribution presents a control strategy employing a concurrent learning (CL)-based DNN training algorithm, which combines online adaptive DNN weight adaptation with offline batch-like training updates using a recorded data stack. The analysis focuses on the closed-loop performance improvements resulting from the use of optimum CL data-selection algorithms, which ensure that the recorded data stack maintains sufficient data diversity to provide a statistically meaningful representation of the operating conditions using a reduced data set. Specifically, this …

Study Of Output And Behavior Of Llms Using Confidence Framing In Prompt Engineering, Micah Parrilla

Doctoral Dissertations and Master's Theses

While prompt engineering is pivotal for shaping Large Language Model (LLM) outputs, the impact of confidence framing on behavioral calibration remains underexplored. This study investigates the ways in which psychological framing, utilizing techniques such as capability praise, role amplification, and doubt induction, affects linguistic tone, objective accuracy, and internal calibration. A 1,080-trial experimental matrix evaluated six diverse models across factual, logical, coding, and cyber security domains. Analysis using the Kruskal-Wallis H-test revealed highly significant behavioral shifts across all measured dimensions, providing conclusive evidence that the applied frames exert a substantial influence on model performance.

The findings identify a distinct cognitive …

Guardrail Height Safety Requirements Given Recent Crash History And Evolution Of Vehicle Design, Delaney Morgan

Doctoral Dissertations and Master's Theses

Roadside barriers such as guardrails are fundamental to roadway safety, providing a critical last line of defense in preventing vehicles from leaving the roadway and impacting potential hazards. As vehicles are ever changing, it is necessary for guardrail design to adapt in response. Many contemporary vehicles such as sport utility vehicles and light trucks have higher centers of gravity than previous years, while electric vehicles have increased weight. Having sufficient guardrail height is essential to ensure proper engagement with vehicles to prevent loss of containment during impact.

The purpose of this study is to evaluate the performance of current Florida …

Safety-Aware Trajectory Generation For Increased Autonomy In Advanced Air Mobility, Edison Alberto Martinez Samaniego

Doctoral Dissertations and Master's Theses

Advanced Air Mobility (AAM) envisions highly automated aircraft that will enable short and medium range transportation. Unlike conventional aviation, these vehicles are expected to operate closer to populated areas and with increased levels of autonomy, making safe operation under abnormal or degraded conditions a critical requirement. Failures or performance degradation can reduce the maneuvering capability of an aircraft, causing trajectories planned under nominal conditions to become dynamically unfeasible.

This thesis presents a trajectory generation and replanning framework designed to maintain safe and feasible flight under reduced flight envelope conditions for a lift+cruise eVTOL aircraft. A unified control architecture based on …

Quantification Of The Depth-Of-Field In A Self-Aligned Focusing Schlieren System, Alexander Ephraim

Doctoral Dissertations and Master's Theses

This thesis investigates self-aligned focusing schlieren (SAFS) as a step toward future volumetric and quantitative measurements of three-dimensional compressible flows. Conventional schlieren imaging provides valuable visualization of density gradients, but it records only a line-of-sight projection and therefore does not directly resolve the spatial distribution of structures through the depth of the flowfield. SAFS addresses part of this limitation by introducing depth sensitivity, but its depth response has not been well characterized quantitatively. To help lay the foundation for future volumetric and quantitative SAFS methods, this work addresses two related problems. First, calibrated quantitative schlieren imaging is applied to an …

Adaptive Methods Of Resident Space Object Identification For Space Situational Awareness, Evan Pavetto-Stewart

Doctoral Dissertations and Master's Theses

One of the fundamental tenets of Space Situational Awareness (SSA) is the detection and sub sequent identification of Resident Space Objects (RSOs) within unresolved optical space imagery. This function is vital to the documentation and tracking of RSOs in their respective operational orbits, knowledge that is necessary for collision avoidance efforts and Space Domain Awareness (SDA) applications. In previous work, development was begun on a MATLAB program called RSOID to fulfill this purpose by accepting a collection (or ’collect’) of unresolved imagery and outputting a sequence of RSO locations (called a ’tracklet’) that can be used to determine the RSO’s …

Developing A Multi-Band Gnss Remote Sensing Station To Measure Precipitable Water Vapor For Flash Flood Nowcasting, Madison Gleydura

Doctoral Dissertations and Master's Theses

Flash flood nowcasting in Central and Southern Appalachia is particularly challenging due to steep terrain, narrow valleys, highly localized rainfall patterns, and limited measurement coverage. Traditional remote sensing methods, such as Doppler radar and microwave radiometry, suffer from reduced resolution at long range and signal blockage by mountains. GNSS-meteorology offers an established alternative for measuring precipitable water vapor and is currently integrated into several numerical weather models. Recent research demonstrates that commercial-grade GNSS receivers can produce tropospheric products comparable to those from geodetic-grade equipment. The gaps in mountain coverage can be addressed by developing a low-cost, self-contained embedded system that …

Evaluating Uav Visual-Inertial Odometry Trajectory Error And Feature-Level Metrics Over Repetitive Floor Patterns, Anass El Mekkoussi

Doctoral Dissertations and Master's Theses

Visual-Inertial Odometry (VIO) is a widely used state estimation technique for Uncrewed Aerial Vehicle (UAV) navigation in environments where Global Navigation Satellite System (GNSS) signals are unavailable. VIO systems that rely on visual feature tracking are susceptible to performance degradation when operating over surfaces containing repetitive visual textures, where visually similar features can produce ambiguous correspondences that introduce errors into the trajectory estimate. Despite the prevalence of repetitive textures in indoor UAV operating environments such as warehouses, manufacturing facilities, and infrastructure corridors, the specific impact of different repetitive pattern geometries on per-surface VIO accuracy has received limited systematic study, and …

Artificial Intelligence In Human Spaceflight Safety-Critical Systems: A Requirements Framework For Ai-Enabled Computer-Based Control Systems, Liz Bosch

Doctoral Dissertations and Master's Theses

Currently, there is no governing standard that addresses the safe integration of AI into computer-based control systems (CBCS) in human spaceflight. The computer-based control expectations of those safety-critical systems on the International Space Station (ISS) are captured in SSP 50038, Computer-Based Control System Safety Requirements, with one caveat: the standard was not designed with AI applications in mind. SSP 50038 does not cover the probabilistic behavior, opacity, and training-data dependency of modern AI/ML systems. The objectives of this work is to develop an AI taxonomy relevant to safety characteristics (determinism, transparency, data dependency, failure predictability), systematically map AI characteristics against …

Plasmoid Vortex System Retrofit A Sustainability And Efficiency Study On Internal Combustion Engines, Walker Hall

Doctoral Dissertations and Master's Theses

The thesis addresses the persistent inefficiency and environmental degradation caused by internal combustion engines in modern vehicles, a major issue as the automotive industry faces increasing pressure to reduce fuel consumption and greenhouse gas emissions. Internal combustion engines, which power most cars today, convert only about 20-30% of fuel energy into useful work, with the remainder lost as heat and exhaust waste, including carbon monoxide (CO), carbon dioxide (CO₂), hydrocarbons (HC), and nitrogen oxides (NOx). This inefficiency contributes to global carbon emissions, with transportation accounting for approximately 29% of U.S. greenhouse gases in 2021 [1]. As regulatory standards tighten (e.g., …

Reinforcement Learning - Driven Satellite Attitude Recovery: Unknown Faults, Simulation-To-Processor In Loop, Chinmay Mirji, Saeed A Ahmadi

Student Research Symposium (SRS)

Conventional attitude control algorithms often degrade when faced with actuator faults, sensor noise, or system uncertainties. This work presents a reinforcement-learning (RL) framework for satellite attitude recovery under unknown failures, focusing on real-time deployment through a processor-in-the-loop (PIL) setup. A continuous-control DDPG agent is trained in a high-fidelity Python/Basilisk simulation environment, where domain randomization captures variations in inertia, external torque, and actuator limitations to promote robust policy learning.

Demonstrating Sysml V2’S Utility With Syside And Syson For Systems Modeling, Quinn Galen

Student Research Symposium (SRS)

This study highlights the practical utility of SysML v2’s kernel language, a formal, text based foundation for consistent, cross tool model definitions, in Model Based Systems Engineering (MBSE), using Air Traffic Management (ATM) as an illustrative example. SysIDE, an open source textual editor, enables rapid model creation with the kernel’s concise syntax, allowing users to define system components and behaviors (e.g., ATM radar or flight path interactions) with real time validation. SysON, a web based graphical tool, complements this by facilitating collaborative visualization of system architectures. Using ATM as an example case, we can showcase how the kernel language enhances …

Conceptual Exploration Of Film Cooling Techniques In Hydrogen Gas Turbines, Wen Wu

Student Research Symposium (SRS)

Film cooling is a key heat transfer technique that protects gas turbine blades from extreme temperatures, allowing higher turbine inlet temperatures and greater thermal efficiency. It works by ejecting a thin layer of cooler air from the compressor through small holes onto the hot surface, creating a protective film layer that lowers surface temperature and reduces thermal stress on blades. This process is vital in power generation and propulsion systems that operate near material limits. With growing emphasis on sustainability, film cooling has gained new importance in hydrogen-fueled gas turbines. Hydrogen combustion creates water vaper and low-density exhaust gases, which …

Evaluating Runtime Monitoring For Reinforcement Learning-Based Flight Control, Andrew Zubyk

Doctoral Dissertations and Master's Theses

Ensuring safety in adaptive flight controls systems is an ongoing challenge in aviation, especially as advancements in artificial intelligence and machine learning (AI/ML) trend upwards. Reinforcement learning is becoming more common in aerospace applications due to the ability to improve these models through training.  While models such as reinforcement learning enable controllers to learn complex behaviors from interaction with the environment, their unpredictability in novel or disturbed conditions raises severe concerns in safety-critical domains. This research investigates the integration of runtime monitoring, a real-time assurance technique, with reinforcement learning-based flight controllers to ensure safety and reliability during flight. By supervising …

Initial Development Of Cooperative Aerial And Ground Vehicles Experimental Testbed, Javier S. Robinson, Morad Nazari

Beyond: Undergraduate Research Journal

Heterogeneous multi-agent systems represents a growing area of research in autonomous vehicles, which involves the real-time cooperation of vehicles operating under different roles or dynamical mod- els. While there is plenty of theoretical work, the existing experimental research focuses on cooperation between physically identical vehicles. This is likely because testing heterogeneous vehicles naturally in- volves more complicated dynamics and communication frameworks to ensure compatibility. The goal of the Cooperative Aerial and Ground Vehicles Experimental (CAGE) testbed is to develop an experimen- tal testbed that involves cooperation of two distinct vehicle models: multiple Crazyflie 2.1 quadcopter drones and at least one …

A Tangible Modeling Language For Systems Engineering, Maissane Aik

Student Research Symposium (SRS)

With the continuous growth of technology and system complexity, systems engineering plays a crucial role in ensuring performance, adaptability, and clarity across interconnected processes. Yet, as modeling tools become increasingly abstract and dependent on digital infrastructures, they have drifted away from the tangible, intuitive ways humans naturally think, communicate, and design. Current modeling approaches often require engineers to navigate numerous diagrams and layers of abstraction. To address the gap, this research will focus on creating a novel systems engineering language that reintroduces tangibility into system modeling. The proposed language will represent system elements as modular blocks that capture structure, behavior, …

Computational Study Of Slosh Dynamics And Active Slosh Damping In Spacecraft Propellant Tanks Equipped With A Magneto Active Propellant Management Device, Priyanshu Savaliya

Student Research Symposium (SRS)

The management of liquid propellant in microgravity remains one of the longest-standing issues in spacecraft design. Traditional passive damping techniques using baffles or diaphragms tend to add structural mass and complexity. The current study proposes a novel active slosh damping device which dynamically adjusts the rheology of the damper fluid using electromagnets, simulated in ANSYS Fluent, to actively manage and dampen slosh in an oscillatory excited cylindrical propellant tank. The electromagnetic fields are modulated through a User-Defined Function (UDF) that responds to force feedback simulated in real time via virtual load cells. In Fluent, the interface dynamics of xenon, fuel, …