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Articles 1411 - 1440 of 69093

Full-Text Articles in Physical Sciences and Mathematics

Beach Erosion And Recovery Since Hurricane Ivan In 2004 Along A Headland-Bay Coast In Treasure Beach, Jamaica, Elandé Engelbrecht Jan 2024

Beach Erosion And Recovery Since Hurricane Ivan In 2004 Along A Headland-Bay Coast In Treasure Beach, Jamaica, Elandé Engelbrecht

MSU Graduate Theses

Anthropogenic climate change is causing sea-level rise and shoreline changes that threaten the environment and economy of coastal communities in Caribbean Island nations. To assess this risk, this study quantifies shoreline changes at Treasure Beach in St. Elizabeth Parish on the south coast of Jamaica from 2001 to 2023. The effects of storm events on erosion were also assessed. Over 10 km of shoreline are assessed with about half being sandy pocket beaches ranging from 300 to 900 m in length, separated by rocky headlands and beach rock outcrops. Sand beach erosion trends since 2001 are assessed for seven sandy …

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Time Series Anomaly Detection Using Generative Adversarial Networks, Shyam Sundar Saravanan Jan 2024

Time Series Anomaly Detection Using Generative Adversarial Networks, Shyam Sundar Saravanan

Masters Theses

"Anomaly detection is widely used in network intrusion detection, autonomous driving, medical diagnosis, credit card frauds, etc. However, several key challenges remain open, such as lack of ground truth labels, presence of complex temporal patterns, and generalizing over different datasets. In this work, we propose TSI-GAN, an unsupervised anomaly detection model for time-series that can learn complex temporal patterns automatically and generalize well, i.e., no need for choosing dataset-specific parameters, making statistical assumptions about underlying data, or changing model architectures. To achieve these goals, we convert each input time-series into a sequence of 2D images using two encoding techniques with …

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The Effect Of Social Determinants Of Health On End-Stage Kidney Disease Mortality Across Diverse Adult Populations: Systematic Review And Meta-Analysis, Prince Agyapong Jan 2024

The Effect Of Social Determinants Of Health On End-Stage Kidney Disease Mortality Across Diverse Adult Populations: Systematic Review And Meta-Analysis, Prince Agyapong

Electronic Theses and Dissertations

Background: This systematic review and meta-analysis aimed to examine the influence of social determinants of health (SDOH) on End-Stage Kidney Disease (ESKD) mortality among diverse racial populations. Given the high morbidity and mortality associated with ESKD, understanding the impact of various SDOH factors across different racial groups is crucial for improving patient outcomes.
Methods: A comprehensive literature search was conducted to identify studies reporting on the relationship between SDOH and ESKD mortality using the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) format. Citations were collated in EndNote 21 and screened in Covidence by two independent reviewers, with inter-rater …

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Improving Stream Connectivity In South Dakota, Colton Rainier Curtis Jan 2024

Improving Stream Connectivity In South Dakota, Colton Rainier Curtis

Electronic Theses and Dissertations

Stream connectivity is crucial for fish movement and genetic diversity in fragmented landscapes. Road-crossings often act as barriers, disrupting hydrology and isolating fish populations. The Southeast Aquatic Resources Partnership (SARP) has developed rapid road-crossing assessment protocols and tools to prioritize restoration projects. However, managers lack tools for planning, directing, and initiating roadcrossing assessments. Managers also require modeling approaches to effectively identify and monitor road-crossings across dynamic stream networks. Presented here is a case study offering a roadmap for effective implementation of collaborative road-crossing assessments and prioritization of remediation projects, alongside an exploration of predictive modeling approaches to identify problematic crossings …

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Refining The Inverse Lipschitz Constant For Injective Relu Networks, Cole Rausch Jan 2024

Refining The Inverse Lipschitz Constant For Injective Relu Networks, Cole Rausch

Electronic Theses and Dissertations

In this thesis, we study the Inverse Lipschitz Constant (ILC) of injective ReLU layers. We study the tightness of the ILC lower bound established in Puthawala et al. Our approach has three components. First, we find that the conditions for injectivity on lines yield a weaker condition than the general condition given in Puthawala et al. Second, we perform numerical experiments to judge the tightness of the existing ILC lower bound and find that bound is overly conservative. Third, we identify the source of the potential slack in the proof of the existing ILC bound, and perform further numerical experiments …

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Empowering Kokal: A Decolonized, Community-Led Development Model In Homa Bay County, Kenya, Kennedy Miruka Jan 2024

Empowering Kokal: A Decolonized, Community-Led Development Model In Homa Bay County, Kenya, Kennedy Miruka

Regis University Student Publications (comprehensive collection)

In Homa Bay County, Kenya, a community-led development initiative called the Power Centre is transforming the fight against poverty and powerlessness. Grounded in principles of decolonization and participatory action, this project addresses the root causes of marginalization by empowering residents of Kokal Village to become active agents of change. Through a robust mixed-methods research approach, the project identifies systemic challenges and leverages existing social networks to build a sustainable, locally-owned model for development. The Power Centre implements a three-pronged strategy, focusing on increasing community participation, strengthening existing groups, and fostering collaborative networks to weave a robust support system. By addressing …

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Classification Models Using Python In Industrial/Organizational Psychology, Beyza Ceylan Jan 2024

Classification Models Using Python In Industrial/Organizational Psychology, Beyza Ceylan

Williams Honors College, Honors Research Projects

Companies, industries, and places of business use artificial intelligence and statistics to predict the characteristics of their employees and staff. Data collected from these individuals is also used to make decisions about them regarding their work life, such as promotions, salaries, or within the hiring process. Two models that are commonly used throughout the field of psychology and specifically in industrial/organizational psychology are the linear regression and the logistic regression. Examining different classification models using Python shows the potential that there may be different models that are more accurate in their predictions of employee success, including a Random Forest model …

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Corrosion Inhibitors: Mitigating The Degradation Of Rebar, Jake R. Hughes Jan 2024

Corrosion Inhibitors: Mitigating The Degradation Of Rebar, Jake R. Hughes

Williams Honors College, Honors Research Projects

Our conjecture was twofold: first, that two compounds historically used as food preservatives could act as environmentally friendly inhibitors against rebar corrosion, and second, that molecular properties have a quantifiable influence on inhibition efficiency (%IE). To evaluate the two compounds, cyclic potentiodynamic polarization was used to determine corrosion current density (icorr) and %IE. The “green” inhibitor candidates included sodium metabisulfite and ascorbic acid, which yielded maximum %IE values of -123900% and 91%, respectively. Results indicated that sodium metabisulfite is not a suitable inhibitor, while ascorbic acid showed potential to extend reinforced concrete’s design life without posing health or …

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Determination Of Spore Viability In Concrete Across Several Factors Using Most Probable Number, Samuel Boyer Jan 2024

Determination Of Spore Viability In Concrete Across Several Factors Using Most Probable Number, Samuel Boyer

Williams Honors College, Honors Research Projects

To determine the lowest concentration of spore added to polyurethane-cement composite (PUCCO) particles that can still germinate after curing in concrete. This research project is a small addition to the larger research project being undertaken by Mirza Mohammed Rashiduzzaman for his Masters. The larger project involves the use of fungal spores added in concrete to act as a self-healing component when cracks form in the concrete structure over time. These spores are suspended in a protective oil and loaded into small, hardened sponge-like PUCCO cubes to act as growth points when water and air can reach the PUCCO in the …

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Wetting Transition Of 3d-Printed Surface Features, Delia Weitzel Jan 2024

Wetting Transition Of 3d-Printed Surface Features, Delia Weitzel

Williams Honors College, Honors Research Projects

This project aims to build on the previous research of prior students in the study of the wetting transition of a textured, 3D-printed surface. The surfaces studied will be constructed by a resin printer in the lab and will be composed of an array of uniform, microscopic pillars. Features of the textured surface, such as pillar diameter, pillar spacing, and pillar height, will be varied to study the impact on the wetting transition of water, oil, and a combination of water and oil. The wetting transition is defined as a transition from a state where the surface cavities are occupied …

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The Exponential Function In Discrete Fractional Calculus Under The Delta Operator, Brayton James Link Jan 2024

The Exponential Function In Discrete Fractional Calculus Under The Delta Operator, Brayton James Link

Masters Theses

"Previously the exponential problem in discrete fractional calculus under the nabla operator was solved with the discrete Mittag--Leffler function. We now show the solution to the exponential problem in discrete fractional calculus under the delta operator, providing multiple derivations of the solution with recursion and Laplace transforms. We also share some computational and numerical results of experiments with different orders of difference to display the nature of the solution" -- Abstract, p. iii

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Ontogenetically Driven Changes In The Endocranial Anatomy Of Maiasaura Peeblesorum And Its Implications For Sensory Functions, Emma Puetz Jan 2024

Ontogenetically Driven Changes In The Endocranial Anatomy Of Maiasaura Peeblesorum And Its Implications For Sensory Functions, Emma Puetz

Masters Theses

"Hadrosaurids exhibited extreme morphological diversity and behavioral characteristics that can be compared with other, closely related members of Dinosauria – particularly through the study of neuroanatomy. X-ray CT generated endocrania of the Late Cretaceous saurolophine hadrosaur Maiasaura peeblesorum, known as the “good mother” dinosaur, offers a unique opportunity to compare complex ecological behaviors between non-avian dinosaurs and their modern archosaur relatives. The 3D reconstruction software ORS Dragonfly provided linear and volumetric measurements taken from the digital cranial endocast and endosseous labyrinths of three ontogenetically varied M. peeblesorum specimens from the Two Medicine Formation in Montana that were used to …

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Bicategorical Character Theory, Travis Wheeler Jan 2024

Bicategorical Character Theory, Travis Wheeler

Theses and Dissertations--Mathematics

In 2007, Nora Ganter and Mikhail Kapranov defined the categorical trace, which they used to define the categorical character of a 2-representation. In 2008, Kate Ponto defined a shadow functor for bicategories. With the shadow functor, Dr. Ponto defined the bicategorical trace, which is a generalization of the symmetric monoidal trace for bicategories. How are these two notions of trace related to one another? We’ve used bicategorical traces to define a character theory for 2-representations, and the categorical character is an example.

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Adams Operations On The Burnside Ring From Power Operations, Lewis Dominguez Jan 2024

Adams Operations On The Burnside Ring From Power Operations, Lewis Dominguez

Theses and Dissertations--Mathematics

Topology furnishes us with many commutative rings associated to finite groups. These include the complex representation ring, the Burnside ring, and the G-equivariant K-theory of a space. Often, these admit additional structure in the form of natural operations on the ring, such as power operations, symmetric powers, and Adams operations. We will discuss two ways of constructing Adams operations. The goal of this work is to understand these in the case of the Burnside ring.

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Nonuniform Sampling-Based Breast Cancer Classification, Santiago Posso Jan 2024

Nonuniform Sampling-Based Breast Cancer Classification, Santiago Posso

Theses and Dissertations--Electrical and Computer Engineering

The emergence of deep learning models and their success in visual object recognition have fueled the medical imaging community's interest in integrating these algorithms to improve medical diagnosis. However, natural images, which have been the main focus of deep learning models and mammograms, exhibit fundamental differences. First, breast tissue abnormalities are often smaller than salient objects in natural images. Second, breast images have significantly higher resolutions but are generally heavily downsampled to fit these images to deep learning models. Models that handle high-resolution mammograms require many exams and complex architectures. Additionally, spatially resizing mammograms leads to losing discriminative details essential …

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Cross-Layer Design Of Highly Scalable And Energy-Efficient Ai Accelerator Systems Using Photonic Integrated Circuits, Sairam Sri Vatsavai Jan 2024

Cross-Layer Design Of Highly Scalable And Energy-Efficient Ai Accelerator Systems Using Photonic Integrated Circuits, Sairam Sri Vatsavai

Theses and Dissertations--Electrical and Computer Engineering

Artificial Intelligence (AI) has experienced remarkable success in recent years, solving complex computational problems across various domains, including computer vision, natural language processing, and pattern recognition. Much of this success can be attributed to the advancements in deep learning algorithms and models, particularly Artificial Neural Networks (ANNs). In recent times, deep ANNs have achieved unprecedented levels of accuracy, surpassing human capabilities in some cases. However, these deep ANN models come at a significant computational cost, with billions to trillions of parameters. Recent trends indicate that the number of parameters per ANN model will continue to grow exponentially in the foreseeable …

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Reinforcement Learning: Applying Low Discrepancy Action Selection To Deep Deterministic Policy Gradient, Aleksandr Svishchev Jan 2024

Reinforcement Learning: Applying Low Discrepancy Action Selection To Deep Deterministic Policy Gradient, Aleksandr Svishchev

Electronic Theses and Dissertations

Reinforcement learning (RL) is a subfield of machine learning concerned with agents learning to behave optimally by interacting with an environment. One of the most important topics in RL is how the agent should explore, that is, how to choose actions in order to rate their impact on long-term reward. For example, a simple baseline strategy might be uniformly random action selection. This thesis investigates the heuristic idea that agents will learn faster if they explore by factoring the environment’s state into their decision and intentionally choose actions which are as different as possible from what they have previously observed. …

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Exploring The Consistency Of Flow Regimes Within And Among Ecoregions Of The Southeastern United States, Frank Paul Braun Iv Jan 2024

Exploring The Consistency Of Flow Regimes Within And Among Ecoregions Of The Southeastern United States, Frank Paul Braun Iv

Electronic Theses and Dissertations

Human manipulation of river systems has long been a known contributor to the loss of freshwater biodiversity. By accounting for environmental causes of hydrologic variation among rivers, we can better understand how ecoregion mediates flow regimes and forecast species that may be at risk. Presumably, natural variation associated with ecoregion boundaries exerts strong influence on flow regimes, and may mediate relationships between other features (e.g., land use, dam operations) and hydrology. However, such between-ecoregion variation is poorly investigated, particularly at fine spatial and temporal scales. I characterized 10 hydrologic metrics, representing the five key dimensions of the flow regime (magnitude, …

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Performing Holt-Winters Time Series Forecasting Using Neural Network Based Models, Kazeem Olanrewaju Bankole Jan 2024

Performing Holt-Winters Time Series Forecasting Using Neural Network Based Models, Kazeem Olanrewaju Bankole

Electronic Theses and Dissertations

We show how to create Artificial Neural Network based models for performing the well- known Holt-Winters time series analysis. Our work fares well compared to the well-known Holt-Winter time series prediction method while avoiding the burden of searching for the parameters of the model. We present the theoretical justification of the connection between the two models and experimental results showing the similarities of these models

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Problems In Chemical Graph Theory Related To The Merrifield-Simmons And Hosoya Topological Indices, William B. O'Reilly Jan 2024

Problems In Chemical Graph Theory Related To The Merrifield-Simmons And Hosoya Topological Indices, William B. O'Reilly

Electronic Theses and Dissertations

In some sense, chemical graph theory applies graph theory to various physical sciences. This interdisciplinary field has significant applications to structure property relationships, as well as mathematical modeling. In particular, we focus on two important indices widely used in chemical graph theory, the Merrifield-Simmons index and Hosoya index. The Merrifield-Simmons index and the Hosoya index are two well-known topological indices used in mathematical chemistry for characterizing specific properties of chemical compounds. Substantial research has been done on the two indices in terms of enumerative problems and extremal questions. In this thesis, we survey known extremal results and consider the generalized …

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Scattering Of Electromagnetic Radiation By Bianisotropic Spheres, Maxwell A. Wallace Jan 2024

Scattering Of Electromagnetic Radiation By Bianisotropic Spheres, Maxwell A. Wallace

Electronic Theses and Dissertations

Modern developments in materials science have led to the increased demand for the ability to control electromagnetic radiation at scales smaller than ever. One of the most important areas of research for controlling the manipulation of electromagnetic radiation, has been the studying of novel optical metamaterials, including the most general and complex form, bianisotropic metamaterials (BAMs). With modern developments in nano- engineering, paired with the advancement of more robust theoretical studies of BAMs, the demand for more novel BAM technologies has increased. With the advent of research of unbounded BAM media, as well as the recent extensions of Mie theory …

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A Comparative Analysis Of A Family Of Advanced Iterative Optimization Methods In Nonlinear Regression, Tanmoy Kumar Debnath Jan 2024

A Comparative Analysis Of A Family Of Advanced Iterative Optimization Methods In Nonlinear Regression, Tanmoy Kumar Debnath

Electronic Theses and Dissertations

Classical statistical supervised learning optimization techniques like the Gauss-Newton Iterative Method (GNIM), Weighted Gauss-Newton Iterative Method (WGNIM), Reweighted Gauss-Newton Iterative Method (RGNIM), and Levenberg-Marquart (LM) algorithm extend the nonlinear least squares method. The WGNIM improves model fitting by controlling heteroscedasticity in the linear and nonlinear models. A comparative analysis of the GNIM, WGNIM, RGNIM, and LM methods for fitting nonlinear models is presented. A step-wise diagnosis for structural multicollinearity in the reweighted linearized model is investigated via the Variance Inflation Factor (VIF) to determine variance inflation in the sequence of estimators for the model parameters. Under restricted multicollinearity levels in …

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Mathematical Modeling Of Coupled Heat And Mass Transfer In Metal-Hydride Hydrogen Storage Systems, Muhammad Hasnain Jan 2024

Mathematical Modeling Of Coupled Heat And Mass Transfer In Metal-Hydride Hydrogen Storage Systems, Muhammad Hasnain

Electronic Theses and Dissertations

As a promising clean energy carrier hydrogen has recently gained significant interest, but its efficient and safe storage is a major challenge. Compared to the gaseous state and liquid state, metal hydrides (MH) offer a potentially more effective storage approach for hydrogen. However, the main challenge in this approach is the low thermal conductivity of the MH bed that leads to low heat transfer and ultimately to higher charging and discharging times. The purpose of this work is to develop an in-house comprehensive heat and mass transfer model for hydrogen sorption in MH reactors to simulate the dynamic behavior of …

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The De Rham Cohomology Of A Lie Group Modulo A Dense Subgroup, Brant Clark Jan 2024

The De Rham Cohomology Of A Lie Group Modulo A Dense Subgroup, Brant Clark

Electronic Theses and Dissertations

Let $H$ be a dense subgroup of a Lie group $G$ with Lie algebra $\LG$. We show that the (diffeological) de Rham cohomology of $G/H$ equals the Lie algebra cohomology of $\LG/\LH$, where $\LH$ is the ideal \mbox{$\{Z\in\LG:\e{tZ}\in H \text{ for all } t\in\RR\}$}

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Geoelectrical And Hydrochemical Characterization Of Submarine Groundwater Discharge In Florida Bay, Ifeanyi Emmanuel Eze Jan 2024

Geoelectrical And Hydrochemical Characterization Of Submarine Groundwater Discharge In Florida Bay, Ifeanyi Emmanuel Eze

Electronic Theses and Dissertations

Florida Bay, situated at the southern tip of Everglades National Park and underlain by the Miami Limestone formation, is an ecosystem of global significance. Over the past century, the bay has faced threats such as droughts, seagrass mortality, and hypersalinity. Despite various studies and management efforts, the dynamics of submarine groundwater discharge (SGD) in the region remain underexplored. Given that SGD plays a significant role in the chemical dynamics of coastal ecosystems, it warrants thorough investigation. This study aims to characterize the spatial and temporal patterns of SGD in Florida Bay by surveying three basins – Rankin, Whipray, and Rabbit …

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Chemoselective Reduction Of Dicarboxylic Acids Via Iridium Catalyzed Hydrosilylation, Linda Lallawmsangi Jan 2024

Chemoselective Reduction Of Dicarboxylic Acids Via Iridium Catalyzed Hydrosilylation, Linda Lallawmsangi

Chemistry & Biochemistry Theses

Reduction of esters to aldehydes poses a challenge since the resulting aldehydes are often more reactive than the initial esters toward nucleophilic hydride-reducing agents. Although bulky, more controllable reducing agents such as lithium tri-tert-butoxyaluminum hydride or diisobutylaluminum hydride (DIBAL-H) have been developed, they are hazardous, sensitive to moisture and air, needing strict reaction conditions, and unsuitable with a wide range of functional groups. We present the design of an iridium-catalyzed chemoselective hydrosilylation method for dicarboxylic imides, followed by hydrolysis to eliminate the amide and yield aldehydes. This approach offers versatility in general reduction chemistry, holds promise for application …

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Novel Time Projection Chamber Techniques With Applications Towards Neutrinoless Double Beta Decay Searches, Nicholas K. Byrnes Jan 2024

Novel Time Projection Chamber Techniques With Applications Towards Neutrinoless Double Beta Decay Searches, Nicholas K. Byrnes

Physics Dissertations

One of the highest priority endeavors in nuclear and particle physics is the search for Neutrinoless Double Beta Decay (0νββ). The observation of 0νββ would prove that the neutrino is a Majorana particle i.e. its own antiparticle, offering a mechanism by which the matter-antimatter asymmetry observed in our universe could be explained. This theoretical decay mechanism is only energetically favored in certain neutron-rich isotopes and, if found, would be the rarest decay process ever observed. To compete with the exceedingly long half-life of 0νββ, all contemporary searches are focused on the following detector performance metrics: Increasing the instrumented isotopic mass …

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On Graph Decompositions And Designs: Exploring The Hamilton-Waterloo Problem With A Factor Of 6-Cycles And Projective Planes Of Order 16, Zazil Santizo Huerta Jan 2024

On Graph Decompositions And Designs: Exploring The Hamilton-Waterloo Problem With A Factor Of 6-Cycles And Projective Planes Of Order 16, Zazil Santizo Huerta

Dissertations, Master's Theses and Master's Reports

This dissertation tackles the challenging graph decomposition problem of finding solutions to the uniform case of the Hamilton-Waterloo Problem (HWP). The HWP seeks decompositions of complete graphs into cycles of specific lengths. Here, we focus on cases with a single factor of 6-cycles. The dissertation then delves into the construction of 1-rotational designs, a concept from finite geometry. It explores the connection between these designs and finite projective planes, which are specific geometric structures. Finally, the dissertation proposes a potential link between these seemingly separate areas. It suggests investigating whether 1-rotational designs might hold the key to solving unsolved instances …

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Dirichlet Problems In Perforated Domains, Robert Righi Jan 2024

Dirichlet Problems In Perforated Domains, Robert Righi

Theses and Dissertations--Mathematics

We establish W1,p estimates for solutions uε to the Laplace equation with Dirichlet boundary conditions in a bounded C1 domain Ωε, η perforated by small holes in ℝd. The bounding constants will depend explicitly on epsilon and eta, where epsilon is the order of the minimal distance between holes, and eta denotes the ratio between the size of the holes and epsilon. The proof relies on a large-scale Lp estimate for ∇uε, whose proof is divided into two main parts. First, we show that solutions of an intermediate problem for a …

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Uniform Regularity Estimates For The Stokes System In Perforated Domains, Jamison R. Wallace Jan 2024

Uniform Regularity Estimates For The Stokes System In Perforated Domains, Jamison R. Wallace

Theses and Dissertations--Mathematics

We consider the Stokes equations in an unbounded domain $\omega_{\epsilon,\eta}$ perforated by small obstacles, where $\epsilon$ represents the minimal distance between obstacles and $\eta$ is the ratio between the obstacle size and $\epsilon$. We are able to obtain uniform $W^{1,q}$ estimates for solutions to the Stokes equations in such domains with bounding constants depending explicitly on $\epsilon$ and $\eta$.

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