Other Physical Sciences and Mathematics Commons^™

A New Approach To Generate Combinatorial Patterns In Logical Analysis Of Data And Its Application To Predict College Retention, Salihah Ahmed E. Jaafari

Theses and Dissertations

Student retention and degree completion remain central challenges for higher-education institutions, with significant implications for student success, institutional effectiveness, and public accountability. While advances in predictive analytics have enabled earlier identification of students at risk of withdrawal, many commonly used machine learning approaches suffer from limited interpretability, constraining their practical usefulness for advising, intervention, and policy decision making. This dissertation addresses the problem of predicting student persistence by developing and evaluating optimization based, interpretable classification models within the Logical Analysis of Data (LAD) framework. Building on existing LAD formulations, this research introduces two novel pattern generation models, the Best Term …

Machine Learning For Predicting Prosthetic Limb Movements, Jessica Alexandra Cegarra Arraiz

Theses and Dissertations

This thesis develops and evaluates a deep learning-based prediction model capable of identifying intended limb movement from surfaced electromyography (sEMG) signals using sequence learning techniques. sEMG signals change over time due to multiple factors such as muscle fatigue or user variability. Traditional prosthetics control methods rely on static feature extraction, ignoring how signals change over time, thereby limiting their ability to capture the temporal changes of muscle activity. As a result, these approaches often lead to poor accuracy, robustness, and generalization. Limited experimental validation has been conducted on sequence-based machine learning approaches using temporal sEMG data from publicly available datasets …

Hindcasting The Occurrence Time Of Major Earthquakes Using Machine Learning And Time Series Analysis, Rubidha Devi D

Theses and Dissertations

An earthquake is an intense shaking of the ground that typically occurs when tectonic plates move beneath the surface of the Earth. Scientists analyze historical seismic records and geophysical and atmospheric signs to build models estimating the probability of major earthquakes by detecting patterns and anomalies in data such as ground deformation and seismic waves. This study would help in predicting earthquakes to minimize risks of people and buildings.

The present study investigates the devastating earthquakes along the Chilean subduction zone in South America, linking non-seismic data to machine learning predictions of Outgoing Longwave Radiation (OLR) and Relative Humidity (RH) …

Bridging Scales In Epidemic Modeling From Individuals To Networks And Ecosystems, Saiprasasd Vr

Theses and Dissertations

Epidemics have shaped the trajectory of human history, repeatedly exposing vulnerabilities in healthcare systems and influencing socio-economic dynamics on a global scale. The COVID-19 pandemic, in particular, underscored the pressing need for flexible and responsive modeling framework capable of adapting to dynamic and evolving epidemic scenarios. Motivated by these challenges, this thesis explores the development of innovative epidemic models that integrate classical mathematical modeling techniques, network-based frameworks, and modern data-driven approaches. Each chapter addresses a distinct dimension of epidemic spread, from vaccination dynamics and community coupling to ecological complexity and adaptive human behavior, culminating in a model-free paradigm suitable for …

Analysis Of Retrial Queueing Systems With Working Vacations And Breakdown Services, Sundararaman M

Theses and Dissertations

The Chapter One titled “Introduction and Preliminaries” deals with the basic definition of queues; characteristics of the queueing theory. It also presents the motivation for this thesis. The literature survey in the area of retrial queue with different phases of service, priority arrivals, feedback, breakdowns, repairs, working vacations and working breakdown service models together with their applications are analyzed.

In Chapter Two “Analysis of an M/G/1 Retrial Queueing System with Priority Customers Under J number of Working Vacations” elaborates on a single server retrial queueing system with priority arrivals under J number of working vacations. If an arriving priority customer …

Investigations On V2o5 And Its Derivative Nanocomposites For Photocatalytic Textile Organic Dye Degradation, Jenifer A

Theses and Dissertations

In recent times, organic dyes from industrial sludge become one of the significant causes of water contamination due to their utility in textile and paper manufacturing industries. These organic dyes are highly toxic and carcinogenic. Fortunately, the photocatalytic degradation process is a practical tool for decomposing toxic organic matter in wastewater by utilizing light. The photodegradation process can be performed using semiconductor materials to purify wastewater. Thus, semiconductor photocatalysis is a desirable alternative technique for decolorizing various organic pollutants.

In this context, the present work reports the preparation and characterization of V2O5 nanocomposites by facile methods and tests them against …

Robustness Of Aging Transition In Competing Effect Of Heterogeneity And Symmetry Breaking Coupling, Gowthaman I

Theses and Dissertations

The knowledge of emergent dynamics and the mechanisms by which self-organizing complex systems operate is a perennially difficult problem that can be effectively resolved by employing an ensemble of coupled dynamical units as a framework. Several intriguing collective dynamical behaviors, such as synchronization, chimera, clustering, oscillation quenching, etc., have been reported using an ensemble of coupled oscillators. Failure or degradation in the performance of even one of the local oscillators in a network of oscillators can lead to cascading failures resulting in the collapse of the entire network such as power blackouts. Similar dynamics can also be observed among neuronal …

Electrocatalysis By Design: Low Dissolution Counter Electrode And Highly Efficient Nanostructured Electrocatalysts, Menna Hasan

Theses and Dissertations

Water Electrolysis is one of the most promising techniques to generate H2 gas, which is an alternative clean source of energy. Hydrogen provides almost three times the energy provided by gasoline, helping to solve the global warming problem caused by the currently used fossil fuels. As any electrochemical reaction is composed of two half reactions, a setup of working and counter electrodes is used to study the catalytic activity towards the targeted reaction, where each electrode carries one of the two-half reactions. In this dissertation, the stability of a number of the commonly used counter electrodes was examined to identify …

Use Of Consumer Grade Small Unmanned Aerial Systems (Suas) For Mapping Storm Damage In Forested Environments, James Dewey Cox

Theses and Dissertations

Storm damages to forested environments pose significant challenges to landowners, land managers, and conservationists alike. Damage scope and scale assessments can be difficult, costly, and time consuming with conventional pedestrian survey techniques. Consumer grade sUAS technology offers an efficient, cost-effective way to accurately assess storm damage in small to moderate sized survey areas (less than 10 km²). Data were collected over a 0.195 km² area of damaged timber within the Kisatchie National Forest in Central Louisiana using a DJI Mavic 2 Pro drone. Collected imagery was processed into an orthomosaic using Agisoft Metashape Professional with a resulting ground sampling distance …

Computational Study Of Radical Cation Rearrangements, Mi'kayla D. Word

Theses and Dissertations

A radical cation is a molecule that has one unpaired electron that holds a positive charge. The unpaired electron within a radical cation causes the molecule to be reactive. The high reactivity of these species allows for radical cations to be commonly studied experimentally using mass spectrometry and other multi-mass imaging techniques. However, these methods often cannot resolve the reaction mechanisms for these fast reactions. Specifically, radical cation rearrangement mechanisms are particularly unresolved within experiments. For this reason, radical cation rearrangements are computationally investigated to explain complex reaction pathways for processes to understand reactions leading to the initiation of detonation …

Modeling Vegetation Effects On Barrier Island Evolution, Eric W. Schoen

Theses and Dissertations

Barrier islands play a significant role in protecting coastlines and harboring coastal habitats. In an effort to study and better understand the evolution of barrier island systems, a cellular model capturing various meteorological and environmental processes is proposed. Erosion due to wind, gravity, and marine processes are coupled with plant population effects. We demonstrate the inhibition of plant cover on sediment mobility, island migration, and erosion in the presence of sea level rise.

Modeling The Evolution Of Barrier Islands, Greg Robson

Theses and Dissertations

Barrier islands form off the shore of many coastal areas and serve as the first line of defense, protecting littoral communities against storms. To study the effects that climate change has on barrier islands, we use a cellular model of wind erosion, surface dynamics, beach dynamics, marsh dynamics, and vegetation development. We will show the inhibition of movement when vegetation is present.

Modeling The Distribution Of Lightning Strike Distances Outside A Preexisting Lightning Area, Dawn L. Sanderson

Theses and Dissertations

Air Force Instruction 91-203 (AFI 91-203) directs that a lightning warning be issued when lightning is occurring or imminent within a 5 nautical mile (NM) radius of a predetermined location or activity. The 45 Weather Squadron (WS), located on the central eastern coast of Florida, balances the safety of personnel and space launch vehicles with lost productivity of taking shelter from lightning. The primary objective of this study investigates if this 5 NM safety radius can be reduced while maintaining a desired level of safety. The research uses processed Lightning Detection and Ranging (LDAR) data to map the movement of …

Genetic Diversity Comparison Among Invasive Fish Populations (Nemipterus Randalli And Serranus Cabrilla) From Mediterranean And Red Sea Coastal Waters Using Cytochrome C Oxidase Subunit I (Coi), Joel Ogwang

Theses and Dissertations

Since the Suez Canal connected the Red Sea with the Mediterranean, several fish species have migrated between the two seas. Nemipterus randalli has crossed from the Red Sea to the Mediterranean (Lessepsian migration) whereas Serranus cabrilla is considered to have crossed in the reverse direction (anti-Lessepsian migration). Genetic variation between populations of these fish species on either side of the Suez Canal might provide valuable information on their patterns of migration. In this study, 600 bp of cytochrome c oxidase subunit I (COI) sequences were used to compare genetic diversity of populations of N. randalli from the eastern Mediterranean with …

Kings In The Direct Product Of Digraphs, Morgan Norge

Theses and Dissertations

A k-king in a digraph D is a vertex that can reach every other vertex in D by a directed path of length at most k. A king is a vertex that is a k-king for some k. We will look at kings in the direct product of digraphs and characterize a relationship between kings in the product and kings in the factors. This is a continuation of a project in which a similar characterization is found for the cartesian product of digraphs, the strong product of digraphs, and the lexicographic product of digraphs.

A Computational Tool For Evaluating Thz Imaging Performance In Brownout Conditions At Land Sites Throughout The World, Seth L. Marek

Theses and Dissertations

This study quantifies terahertz (THz) or sub-millimeter imaging performance during simulated rotary-wing brownout or whiteout environments based on geographic location and recent/current atmospheric weather conditions. The atmospheric conditions are defined through the Air Force Institute of Technology Center for Directed Energy (AFIT/CDE) Laser Environmental Effects Definition and Reference or LEEDR model. This model enables the creation of vertical profiles of temperature, pressure, water vapor content, optical turbulence, and atmospheric particulates and hydrometeors as they relate to line-by-line layer extinction coefficient magnitude at wavelengths from the UV to the RF. Optical properties and realistic particle size distributions for the brownout and …

Modeling Thermal Inactivation Of Bacillus Spores, Emily A. Knight

Theses and Dissertations

This research models and analyzes methods to damage Bacillus anthracis spores through heat treatment. AFIT researchers have developed methods to characterize the effects of heating spores to high temperatures and for short durations similar to the thermal pulse of conventional weapon detonation. This research models the current experiment and evaluates the rate of thermal diffusion throughout the spores. A micro-model of the effects of dry and wet heating on a spore is presented. Heating a spore energizes adsorbed, absorbed, and chemically bound water molecules. These energized molecules have greater mobility within the spore, as well as between the spore and …

Development Of Quasi-Likelihood Techniques For The Analysis Of Pseudo-Proportional Data, Jennifer A. Elder

Theses and Dissertations

In certain experimental situations, the data observed are pseudo-proportional. By this, we observe the numerator, the number of responders, but the denominator, the total number, is random and, possibly, unobserved. In such situations, the data often exhibit "extra" variability due to the randomness of the denominator. Analysis of these data should account for this overdispersion. Several authors have proposed parametric approaches to this problem. Finney [Biometrika (1949) 36, 239-256] proposed the use of a mixture of the binomial and Poisson distributions. Anscombe [Annals of Applied Biology (1949) 36, 203-205] discussed the use of a mixture of the binomial and negative …