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Electronic Theses and Dissertations

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Full-Text Articles in Physical Sciences and Mathematics

Mode Coupling In Space-Division Multiplexed Systems, Huiyuan Liu Jan 2019

Mode Coupling In Space-Division Multiplexed Systems, Huiyuan Liu

Electronic Theses and Dissertations

Even though fiber-optic communication systems have been engineered to nearly approach the Shannon capacity limit, they still cannot meet the exponentially-growing bandwidth demand of the Internet. Space-division multiplexing (SDM) has attracted considerable attention in recent years due to its potential to address this capacity crunch. In SDM, the transmission channels support more than one spatial mode, each of which can provide the same capacity as a single-mode fiber. To make SDM practical, crosstalk among modes must be effectively managed. This dissertation presents three techniques for crosstalk management for SDM. In some cases such as intra-datacenter interconnects, even though mode crosstalk …

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Hadwiger Numbers And Gallai-Ramsey Numbers Of Special Graphs, Christian Bosse Jan 2019

Hadwiger Numbers And Gallai-Ramsey Numbers Of Special Graphs, Christian Bosse

Electronic Theses and Dissertations

This dissertation explores two separate topics on graphs. We first study a far-reaching generalization of the Four Color Theorem. Given a graph G, we use chi(G) to denote the chromatic number; alpha(G) the independence number; and h(G) the Hadwiger number, which is the largest integer t such that the complete graph K_t can be obtained from a subgraph of G by contracting edges. Hadwiger's conjecture from 1943 states that for every graph G, h(G) is greater than or equal to chi(G). This is perhaps the most famous conjecture in Graph Theory and remains open even for graphs G with alpha(G) …

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Seascape Genetics And Rehabilitation Efficiency In The Florida Manatee, Madison Hall Jan 2019

Seascape Genetics And Rehabilitation Efficiency In The Florida Manatee, Madison Hall

Electronic Theses and Dissertations

The Florida manatee (Trichechus manatus latirostris) was recently downlisted federally from "endangered" to "threatened" despite acknowledgments of remaining threats to long term population persistence. Challenges to future manatee conservation include, but are not limited to, increases in frequency of harmful algal blooms, intensifying anthropogenic disturbance, and loss of warm-water habitat. The goals of this dissertation were 1) to assess threats to the manatee via a comprehensive, long-term (1973-2016), retrospective analysis of the manatee rescue and rehabilitation partnership (MRRP) and 2) to use seascape genetics analysis to examine whether abiotic, biotic, or anthropogenic seascape variables could significantly describe genetic distance patterns …

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Variational Inclusions With General Over-Relaxed Proximal Point And Variational-Like Inequalities With Densely Pseudomonotonicity, George Nguyen Jan 2019

Variational Inclusions With General Over-Relaxed Proximal Point And Variational-Like Inequalities With Densely Pseudomonotonicity, George Nguyen

Electronic Theses and Dissertations

This dissertation focuses on the existence and uniqueness of the solutions of variational inclusion and variational inequality problems and then attempts to develop efficient algorithms to estimate numerical solutions for the problems. The dissertation consists a total of five chapters. Chapter 1 is an introduction to variational inequality problems, variational inclusion problems, monotone operators, and some basic definitions and preliminaries from convex analysis. Chapter 2 is a study of a general class of nonlinear implicit inclusion problems. The objective of this study is to explore how to omit the Lipschitz continuity condition by using an alternating approach to the proximal …

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Estimation And Clustering In Statistical Ill-Posed Linear Inverse Problems, Rasika Rajapakshage Jan 2019

Estimation And Clustering In Statistical Ill-Posed Linear Inverse Problems, Rasika Rajapakshage

Electronic Theses and Dissertations

The main focus of the dissertation is estimation and clustering in statistical ill-posed linear inverse problems. The dissertation deals with a problem of simultaneously estimating a collection of solutions of ill-posed linear inverse problems from their noisy images under an operator that does not have a bounded inverse, when the solutions are related in a certain way. The dissertation defense consists of three parts. In the first part, the collection consists of measurements of temporal functions at various spatial locations. In particular, we study the problem of estimating a three-dimensional function based on observations of its noisy Laplace convolution. In …

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High Performance Liquid Crystal Devices For Augmented Reality And Virtual Reality, Md Javed Rouf Talukder Jan 2019

High Performance Liquid Crystal Devices For Augmented Reality And Virtual Reality, Md Javed Rouf Talukder

Electronic Theses and Dissertations

See-through augmented reality and virtual reality displays are emerging due to their widespread applications in education, engineering design, medical, retail, transportation, automotive, aerospace, gaming, and entertainment. For augmented reality and virtual reality displays, high-resolution density, high luminance, fast response time and high ambient contrast ratio are critically needed. High-resolution density helps eliminate the screen-door effect, high luminance and fast response time enable low duty ratio operation, which plays a key role for suppressing image blurs. A dimmer placed in front of AR display helps to control the incident background light, which in turn improves the image contrast. In this dissertation, …

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The Schrödinger Equation With Coulomb Potential Admits No Exact Solutions, Ilia Toli Jan 2019

The Schrödinger Equation With Coulomb Potential Admits No Exact Solutions, Ilia Toli

Electronic Theses and Dissertations

We prove that the Schrödinger equation with the electrostatic potential energy expressed by the Coulomb potential does not admit exact solutions for three or more bodies. It follows that the exact solutions proposed by Fock [1–3] are flawed. The Coulomb potential is the problem. Based on the classical (non-quantum) principle of superposition, the Coulomb potential of a system of many particles is assumed to be the sum of all the pairwise Coulomb potentials. We prove that this is not accurate. The Coulomb potential being a hyperbolic (not linear) function, the superposition principle does not apply. The Schrödinger equation as studied …

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Two Ramsey-Related Problems, Jingmei Zhang Jan 2019

Two Ramsey-Related Problems, Jingmei Zhang

Electronic Theses and Dissertations

Extremal combinatorics is one of the central branches of discrete mathematics and has experienced an impressive growth during the last few decades. It deals with the problem of determining or estimating the maximum or minimum possible size of a combinatorial structure which satisfies certain requirements. In this dissertation, we focus on studying the minimum number of edges of certain co-critical graphs. Given an integer r ≥ 1 and graphs G; H1; : : : ;Hr, we write → G (H1; : : : ;Hr) if every r-coloring of the edges of G contains a monochromatic copy of Hi in color …

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Imaging Through Glass-Air Anderson Localizing Optical Fiber, Jian Zhao Jan 2019

Imaging Through Glass-Air Anderson Localizing Optical Fiber, Jian Zhao

Electronic Theses and Dissertations

The fiber-optic imaging system enables imaging deeply into hollow tissue tracts or organs of biological objects in a minimally invasive way, which are inaccessible to conventional microscopy. It is the key technology to visualize biological objects in biomedical research and clinical applications. The fiber-optic imaging system should be able to deliver a high-quality image to resolve the details of cell morphology in vivo and in real time with a miniaturized imaging unit. It also has to be insensitive to environmental perturbations, such as mechanical bending or temperature variations. Besides, both coherent and incoherent light sources should be compatible with the …

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Asteroid Surfaces: The Importance Of Cohesive Forces, Keanna Jardine Jan 2019

Asteroid Surfaces: The Importance Of Cohesive Forces, Keanna Jardine

Electronic Theses and Dissertations

Adhesive forces play a significant role on airless bodies due to their weak gravities. Investigating adhesion at the surface of asteroids and their constituent components is vital to understanding their formation and evolution. Previous research has been done to understand the interaction of micron-sized spheres to planar surfaces and sphere-to-sphere interactions, which have been used to develop models of asteroid surfaces. Our investigation experimentally investigates adhesion through atomic force microscopy (AFM) measurements between JSC-1 simulant particles and several AFM tips, including a typical pyramidal gold tip and microspheres of sizes 2 μm and 15 μm. The samples of JSC-1 consist …

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Remediation Of Chlorinated Alkanes By Zero Valent Iron With Vitamin B12 And Utilization Of A Modified Gradual Release Of Responsibility Model In A Large Enrollment Chemistry Course, Nicole Lapeyrouse Jan 2019

Remediation Of Chlorinated Alkanes By Zero Valent Iron With Vitamin B12 And Utilization Of A Modified Gradual Release Of Responsibility Model In A Large Enrollment Chemistry Course, Nicole Lapeyrouse

Electronic Theses and Dissertations

The following dissertation looks at addressing environmental contaminants in the environment and the integration of an active learning style in an introductory chemistry course. It begins with addressing the concern for chlorinated propanes and ethane in the environment and the importance of looking into environmental remediation applications. This research looks at incorporating vitamin B12 as an environmentally friendly catalyst in the presence of zero valent iron for the reduction of chlorinated propanes and ethane. Chapter 2 presents the analytical methods and conditions in which samples were run. The results from these experiments are discussed in length in Chapter 3. Our …

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A Complete Approach To Predict Biodistribution Of Nanomaterials Within Animal Species From In-Vitro Data, Edward Price Jan 2019

A Complete Approach To Predict Biodistribution Of Nanomaterials Within Animal Species From In-Vitro Data, Edward Price

Electronic Theses and Dissertations

Smart drug-design for antibody and nanomaterial-based therapies allows for optimization of drug efficacy and more efficient early-stage pre-clinical trials. The ideal drug must display maximum efficacy at target tissue sites, but to track and predict distribution to these sites, one must have a mechanistic understanding of the kinetics involved with the individual cells of the tissue itself. This process can be tracked through biological simulations coupled with in-vitro approaches, which result in a rapid and efficient in-depth understanding of drug transport within tissue vasculature and cellular environment. As a result, it becomes possible to predict drug biodistribution within live animal …

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Visual-Textual Video Synopsis Generation, Aidean Sharghi Karganroodi Jan 2019

Visual-Textual Video Synopsis Generation, Aidean Sharghi Karganroodi

Electronic Theses and Dissertations

In this dissertation we tackle the problem of automatic video summarization. Automatic summarization techniques enable faster browsing and indexing of large video databases. However, due to the inherent subjectivity of the task, no single video summarizer fits all users unless it adapts to individual user's needs. To address this issue, we introduce a fresh view on the task called "Query-focused'' extractive video summarization. We develop a supervised model that takes as input a video and user's preference in form of a query, and creates a summary video by selecting key shots from the original video. We model the problem as …

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Solution Of Linear Ill-Posed Problems Using Overcomplete Dictionaries, Pawan Gupta Jan 2019

Solution Of Linear Ill-Posed Problems Using Overcomplete Dictionaries, Pawan Gupta

Electronic Theses and Dissertations

In this dissertation, we consider an application of overcomplete dictionaries to the solution of general ill-posed linear inverse problems. In the context of regression problems, there has been an enormous amount of effort to recover an unknown function using such dictionaries. While some research on the subject has been already carried out, there are still many gaps to address. In particular, one of the most popular methods, lasso, and its variants, is based on minimizing the empirical likelihood and unfortunately, requires stringent assumptions on the dictionary, the so-called, compatibility conditions. Though compatibility conditions are hard to satisfy, it is well …

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Catalytic Properties Of Defect-Laden 2d Material From First-Principles, Tao Jiang Jan 2019

Catalytic Properties Of Defect-Laden 2d Material From First-Principles, Tao Jiang

Electronic Theses and Dissertations

Two dimensional (2D) materials offer excellent opportunities for application as catalysts for energy needs. Their catalytic activity depends on the nature of defects, their geometry and their electronic structure. It thus important that the characteristics of defect-laden 2D materials be understood at the microscopic level. My dissertation focuses on theoretical and computational studies of several novel nanoscale materials using state-of-the-art techniques based on density functional theory (DFT) with the objective of understanding the microscopic factors that control material functionality. My work has helped establish defect-laden hexagonal boron nitride (dh-BN) as a promising metal-free catalyst for CO2 hydrogenation. Firstly, I showed …

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Sub-Terahertz Spin Pumping From An Insulating Antiferromagnet, Priyanka Vaidya Jan 2019

Sub-Terahertz Spin Pumping From An Insulating Antiferromagnet, Priyanka Vaidya

Electronic Theses and Dissertations

The combination of the spin transfer torque and spin Hall effects, or their reciprocal dynamical spin pumping and inverse spin Hall effects, respectively, enable reading and controlling the magnetization state in spintronics devices which are at the verge of mass commercialization as the next generation of energy-efficient and fast magnetic random-access memory applications with the use of ferromagnetic elements, e.g., the spin valve. However, these effects have remained elusive in antiferromagnetic-based devices up to date, despite the fascinating advantages offered by the absence of stray fields (zero net magnetization), Terahertz spin dynamics, and the widespread availability of metallic, insulating and …

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Nanoplasmonics In Two-Dimensional Dirac And Three-Dimensional Metallic Nanostructure Systems, Alireza Safaei Jan 2019

Nanoplasmonics In Two-Dimensional Dirac And Three-Dimensional Metallic Nanostructure Systems, Alireza Safaei

Electronic Theses and Dissertations

Surface plasmons are collective oscillation of electrons which are coupled to the incident electric field. Excitation of surface plasmon is a route to engineer the behavior of light in nanometer length scale and amplifying the light-matter interaction. This interaction is an outcome of near-field enhancement close to the metal surface which leads to plasmon damping through radiative decay to outgoing photons and nonradiative decay inside and on the surface of the material to create an electron-hole pair via interband or intraband Landau damping. Plasmonics in Dirac systems such as graphene show novel features due to massless electrons and holes around …

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Novel Solid State Lasers Based On Volume Bragg Gratings, Evan Hale Jan 2019

Novel Solid State Lasers Based On Volume Bragg Gratings, Evan Hale

Electronic Theses and Dissertations

Since their invention in 1960, lasers have revolutionized modern technology, and tremendous amounts of innovation and development has gone into advancing their properties and efficiencies. This dissertation reports on further innovations by presenting novel solid state laser systems based on the volume Bragg gratings (VBGs) and the newly developed holographic phase mask (HPMs) for brightness enhancement, dual wavelength operation, and mode conversion. First, a new optical element was created by pairing the HPM with two surface gratings creating an achromatic holographic phase mask. This new optical device successfully performed transverse mode conversion of multiple narrow line laser sources operating from …

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High-Dynamic-Range Foveated Near-Eye Display System, Guanjun Tan Jan 2019

High-Dynamic-Range Foveated Near-Eye Display System, Guanjun Tan

Electronic Theses and Dissertations

Wearable near-eye display has found widespread applications in education, gaming, entertainment, engineering, military training, and healthcare, just to name a few. However, the visual experience provided by current near-eye displays still falls short to what we can perceive in the real world. Three major challenges remain to be overcome: 1) limited dynamic range in display brightness and contrast, 2) inadequate angular resolution, and 3) vergence-accommodation conflict (VAC) issue. This dissertation is devoted to addressing these three critical issues from both display panel development and optical system design viewpoints. A high-dynamic-range (HDR) display requires both high peak brightness and excellent dark …

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Room Temperature Vox Air-Bridge Bolometer Integrated With Metal-Insulator-Metal Resonant Absorbers, Seth Calhoun Jan 2019

Room Temperature Vox Air-Bridge Bolometer Integrated With Metal-Insulator-Metal Resonant Absorbers, Seth Calhoun

Electronic Theses and Dissertations

Spectrally-selective un-cooled micro-bolometers have many military and industrial applications for infrared sensing and imaging, e.g. target acquisition and chemical analysis. In this work, a micro-bolometer was fabricated with integrated wavelength-selective absorber based on subwavelength metal-insulator-metal (MIM) resonators. The fabricated air-bridge structure used a vanadium oxide thin film as the bolometric element. A novel aqueous deposition method of depositing vanadium oxide was investigated and compared to traditional sputtered vanadium oxide to determine achievable temperature coefficient of resistance. The MIM absorber itself was investigated as a function of the dielectric used, and the strong dependence of the resonance spectrum on dispersion was …

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The Evaluation Of Classifier Performance On The Forensic Analysis Of Fire Debris And The Expansion Of The Substrate Database, Alyssa Allen Jan 2019

The Evaluation Of Classifier Performance On The Forensic Analysis Of Fire Debris And The Expansion Of The Substrate Database, Alyssa Allen

Electronic Theses and Dissertations

The current protocols in fire debris analysis rely on ignitable liquid pattern recognition and the identification of target compounds. These practices allow fire debris analysts to determine whether a sample contains or is absent of ignitable liquid residue and to classify that type of ignitable liquid based upon subjective thresholds. A statistical approach using computationally mixed datasets was devised in this research to generate an objective approach to the classification of fire debris samples and to determine error rates. Quadratic, linear, and partial least squares linear discriminant analysis (QDA, LDA, and PLS-DA) models were developed and evaluated to determine the …

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Towards More Reliable Neural Network Learning Models, Navid Kardan Jan 2019

Towards More Reliable Neural Network Learning Models, Navid Kardan

Electronic Theses and Dissertations

Ideally, when a neural network makes a wrong decision or encounters an out-of-distribution example, its predictive confidence should be as low as possible. Three primary contributions in this dissertation address this challenge. The first two contributions are new approaches to mitigate overconfident predictions in modern neural networks. In the first (1), called competitive overcomplete output layer neural networks, several classifiers, as part of the same output layer, are trained simultaneously and later their consensus produces more reliable predictions. The second approach (2) reformulates the original classification problem into several new versions by combining classes together and training a classifier on …

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Quantitative Aspects Of Interface Remodeling During Germband Extension, Timothy E. Vanderleest Jan 2019

Quantitative Aspects Of Interface Remodeling During Germband Extension, Timothy E. Vanderleest

Electronic Theses and Dissertations

Oriented cell intercalation is an essential developmental process that shapes tissue morphologies through the directional insertion of cells between their neighbors. Intercalary behaviors in the early Drosophila embryo occur through a remodeling of cell topologies, with cells contracting shared AP interfaces to a single point, followed by newly juxtaposed DV cells constructing horizontally-oriented interfaces between them. Previous research has focused on properties of cell-cell interfaces, and led to a model in which actomyosin networks mediate higher line tensions at AP interfaces to direct contraction. However, the contribution of tricellular vertices to tissue elongation remains unclear. This study shows that cell …

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Training Neural Networks Through The Integration Of Evolution And Gradient Descent, Gregory Morse Jan 2019

Training Neural Networks Through The Integration Of Evolution And Gradient Descent, Gregory Morse

Electronic Theses and Dissertations

Neural networks have achieved widespread adoption due to both their applicability to a wide range of problems and their success relative to other machine learning algorithms. The training of neural networks is achieved through any of several paradigms, most prominently gradient-based approaches (including deep learning), but also through up-and-coming approaches like neuroevolution. However, while both of these neural network training paradigms have seen major improvements over the past decade, little work has been invested in developing algorithms that incorporate the advances from both deep learning and neuroevolution. This dissertation introduces two new algorithms that are steps towards the integration of …

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Task Focused Robotic Imitation Learning, Pooya Abolghasemi Jan 2019

Task Focused Robotic Imitation Learning, Pooya Abolghasemi

Electronic Theses and Dissertations

For many years, successful applications of robotics were the domain of controlled environments, such as industrial assembly lines. Such environments are custom designed for the convenience of the robot and separated from human operators. In recent years, advances in artificial intelligence, in particular, deep learning and computer vision, allowed researchers to successfully demonstrate robots that operate in unstructured environments and directly interact with humans. One of the major applications of such robots is in assistive robotics. For instance, a wheelchair mounted robotic arm can help disabled users in the performance of activities of daily living (ADLs) such as feeding and …

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Assessment Of A Surface Water Supply For Source And Treated Distribution System Quality, Angela Rodriguez Jan 2019

Assessment Of A Surface Water Supply For Source And Treated Distribution System Quality, Angela Rodriguez

Electronic Theses and Dissertations

This study focused on providing a source to tap assessment of surface water systems with respect to (i) the use of alternative biomonitoring tools, (ii) disinfection byproduct (DBP) formation and control, and (iii) corrosion control. In the first study component, two water systems were microbiologically evaluated using adenosine triphosphate (ATP) bioluminescence technology. It was determined that microbial ATP was useful as a surrogate for biomonitoring within a surface water system when paired with traditional methods. Although microbial activity differed between distribution systems that used either chloramine or chlorine disinfectant, in both cases flowrate and season affected microbial ATP values. In …

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Multi-Modal Interfaces For Sensemaking Of Graph-Connected Datasets, Anthony Wehrer Jan 2019

Multi-Modal Interfaces For Sensemaking Of Graph-Connected Datasets, Anthony Wehrer

Electronic Theses and Dissertations

The visualization of hypothesized evolutionary processes is often shown through phylogenetic trees. Given evolutionary data presented in one of several widely accepted formats, software exists to render these data into a tree diagram. However, software packages commonly in use by biologists today often do not provide means to dynamically adjust and customize these diagrams for studying new hypothetical relationships, and for illustration and publication purposes. Even where these options are available, there can be a lack of intuitiveness and ease-of-use. The goal of our research is, thus, to investigate more natural and effective means of sensemaking of the data with …

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Design, Synthesis And Characterization Of Biomimetic, Bioinspired And Bio-Related Functional Polymers For Atmospheric Water Recovery, Abdullah Alqassar Jan 2019

Design, Synthesis And Characterization Of Biomimetic, Bioinspired And Bio-Related Functional Polymers For Atmospheric Water Recovery, Abdullah Alqassar

Electronic Theses and Dissertations

Atmospheric water recovery in changing environments has received wide attention in environmental science and engineering communities due to rapid population growth and frequent droughts. This study is focused on the design, synthesis, and characterization of biomimetic, bioinspired, and bio-related functional polymers (b3p) to help resolve the water supply issue especially in arid or semi-arid regions. It is aimed to develop unique synthetic methods to access well-defined polymers with the aid of nanomaterials and metal to produce next generation polymer materials for better atmospheric water recovery. The design of such new b3p is bioinspired by some skin materials of biological species …

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Long-Term Carbon And Copper Impact On Nutrient Removal Via Green Sorption Media In Dynamic Linear Ditch Environments, Diana Ordonez Jan 2019

Long-Term Carbon And Copper Impact On Nutrient Removal Via Green Sorption Media In Dynamic Linear Ditch Environments, Diana Ordonez

Electronic Theses and Dissertations

Nutrient-laden stormwater runoff causes environmental and ecological impacts on receiving water bodies. Biosorption Activated Media (BAM) composed of the sand, tire crumb, and clay have been implemented in stormwater best management practices due to its ability to efficiently remove nutrients from stormwater runoff, such as in roadside linear ditches, via unique chemophysical and microbiological processes. In this study, a set of fixed-bed columns were set up to simulate some external forces in roadside linear ditches and examine how these external forces affect the performance of BAM. In our experiment, scenario 1 simulates the impact that animals such as tortoises, moles …

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Blockchain-Driven Secure And Transparent Audit Logs, Ashar Ahmad Jan 2019

Blockchain-Driven Secure And Transparent Audit Logs, Ashar Ahmad

Electronic Theses and Dissertations

In enterprise business applications, large volumes of data are generated daily, encoding business logic and transactions. Those applications are governed by various compliance requirements, making it essential to provide audit logs to store, track, and attribute data changes. In traditional audit log systems, logs are collected and stored in a centralized medium, making them prone to various forms of attacks and manipulations, including physical access and remote vulnerability exploitation attacks, and eventually allowing for unauthorized data modification, threatening the guarantees of audit logs. Moreover, such systems, and given their centralized nature, are characterized by a single point of failure. To …

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