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Articles 61 - 85 of 85
Full-Text Articles in Physical Sciences and Mathematics
On The Distribution Of Inter-Arrival Times Of 911 Emergency Responseprocess Events, Blake Cameron Moss
On The Distribution Of Inter-Arrival Times Of 911 Emergency Responseprocess Events, Blake Cameron Moss
Theses and Dissertations
The 911 emergency response process is a core component of the emergency services critical infrastructure sector in the United States. Modeling and simulation of a complex stochastic system like the 911 response process enables policy makers and stakeholders to better understand, identify, and mitigate the impact of attacks/disasters affecting the 911 system. Modeling the 911 response process as a series of queue sub-systems will enable analysis into how CI failures impact the different phases of the 911 response process. Before such a model can be constructed, the probability distributions of the inter-arrivals of events into these various sub-systems needs to …
Geometric Extensions Of Neural Processes, Andrew Newberry Carr
Geometric Extensions Of Neural Processes, Andrew Newberry Carr
Theses and Dissertations
Neural Processes (NPs) are a class of regression models that learn a map from a set of input-output pairs to a distribution over functions. NPs are computationally tractable and provide a number of benefits over traditional nonlinear regression models. Despite these benefits, there are two main domains where NPs fail. This thesis is focused on presenting extensions of the Neural Process to these two areas. The first of these is the extension of Neural Processes graph and network data which we call Graph Neural Processes (GNP). A Graph Neural Process is defined as a Neural Process that operates on graph …
Thin Film Deposition On Powder Substrates Using Ald And Its Characterization Using Xps, Tem, And Se, Dhruv Shah
Thin Film Deposition On Powder Substrates Using Ald And Its Characterization Using Xps, Tem, And Se, Dhruv Shah
Theses and Dissertations
The major part of my dissertation consists of thin films deposited using atomic layer deposition on flat and powder substrates. It details the various optimization experiments for process parameters like dose time, purge time, temperature, and pressure on silicon shards and powder substrates. Spectroscopic ellipsometry (SE) was used to characterize these films over a wide wavelength range (191-1688 nm). An optical model with a BEMA (Bruggeman effective medium approximation) layer was used to fit the ellipsometric data to investigate the optical properties of the alumina surface. The optimized process parameters on the flat surfaces were used for coating powder substrates. …
Electrical Characterization And Annealing Of Dna Origami Templated Gold Nanowires, Tyler Richard Westover
Electrical Characterization And Annealing Of Dna Origami Templated Gold Nanowires, Tyler Richard Westover
Theses and Dissertations
DNA origami templates have been studied due the versatility of shapes that can be designed and their compatibility with various materials. This has potential for future electronic applications. This work presents studies performed on the electrical properties of DNA origami templated gold nanowires. Using a DNA origami tile, gold nanowires are site specifically attached in a “C” shape, and with the use of electron beam induced deposition of metal, electrically characterized. These wires are electrically conductive with resistivities as low as 4.24 x 10-5 Ω-m. During moderate temperature processing nanowires formed on DNA origami templates are shown to be affected …
Organic Synthesis Using Bimetallic Catalysis, Chloe Christine Ence
Organic Synthesis Using Bimetallic Catalysis, Chloe Christine Ence
Theses and Dissertations
Bimetallic Catalysis is an emerging field of study that uses two metals to cooperatively perform organic transformations. These metals can serve to activate or bind substrates in order to increase the rate and selectivity of reactions. This work first describes the synthesis and utilization of six new chiral, titanium-containing phosphinoamide ligands. These Lewis acidic ligands withdraw electron density from an active palladium center to induce chirality and increase the rate of allylic amination of hindered, secondary N-alkyl amines. X-ray quality crystals were grown for each ligand and completed the allylic amination of hindered secondary amines in minutes whereas other non-titanium-containing …
Comparative Genomics Using The Colored De Bruijn Graph, Cole Andrew Lyman
Comparative Genomics Using The Colored De Bruijn Graph, Cole Andrew Lyman
Theses and Dissertations
Comparing genomes in a computationally efficient manner is a difficult problem. Methods that provide the highest resolution are too inefficient and methods that are efficient are too low resolution. In this thesis, we show that the Colored de Bruijn Graph (CdBG) is a suitable method for comparing genomes because it is efficient while maintaining a useful amount of resolution. To illustrate the usefulness of the CdBG, the phylogenetic tree for 12 species in the Drosophila genus is reconstructed using pseudo-homologous regions of the genome contained in the CdBG.
Superconductivity At Its Limit: Simulating Superconductor Dynamics Near The Superconducting Superheating Field In Eilenberger And Ginzburg-Landau Theory, Alden Roy Pack
Theses and Dissertations
We computationally explore the dynamics of superconductivity near the superheating field in two ways. First, we use a finite element method to solve the time-dependent Ginzburg-Landau equations of superconductivity. We present a novel way to evaluate the superheating field Hsh and the critical mode that leads to vortex nucleation using saddle-node bifurcation theory. We simulate how surface roughness, grain boundaries, and islands of deficient Sn change those results in 2 and 3 spatial dimensions. We study how AC magnetic fields and heat waves impact vortex movement. Second, we use automatic differentiation to abstract away the details of deriving the equations …
Chaotic Model Prediction With Machine Learning, Yajing Zhao
Chaotic Model Prediction With Machine Learning, Yajing Zhao
Theses and Dissertations
Chaos theory is a branch of modern mathematics concerning the non-linear dynamic systems that are highly sensitive to their initial states. It has extensive real-world applications, such as weather forecasting and stock market prediction. The Lorenz system, defined by three ordinary differential equations (ODEs), is one of the simplest and most popular chaotic models. Historically research has focused on understanding the Lorenz system's mathematical characteristics and dynamical evolution including the inherent chaotic features it possesses. In this thesis, we take a data-driven approach and propose the task of predicting future states of the chaotic system from limited observations. We explore …
Supporting Support Engineers, Esdras Kutomi
Supporting Support Engineers, Esdras Kutomi
Theses and Dissertations
The steady and uninterrupted availability of systems is essential for the mission of many companies and other organizations. This responsibility relies mostly upon support engineers, who are responsible to respond to incidents. Incident response is a unique type of task in software engineering, given it carries distinguishing characteristics like risks, pressure, incomplete information and urgency. Despite the importance of this task for many organizations, little can be found in the literature about the incident response task and model. To fill the gap, we created a theoretical foundation to foster research on incident response. We conducted an interview study, asking 12 …
Design, Synthesis, And Characterization Of New Non-Centrosymmetric Organic Crystals For Terahertz Generation, Gabriel Alejandro Valdivia-Berroeta
Design, Synthesis, And Characterization Of New Non-Centrosymmetric Organic Crystals For Terahertz Generation, Gabriel Alejandro Valdivia-Berroeta
Theses and Dissertations
Terahertz (THz) spectroscopy is an emerging technology with promising applications in imaging, homeland security, and material detection and quantification. Frequencies in the THz region can be generated by optical rectification of ultrafast near-infrared laser pulses in the presence of a nonlinear optical (NLO) materials such as organic crystals. Non-centrosymmetric organic THz generating crystals such as DAST, HMQ-TMS, and OH1 have received special attention due to the strong generated fields on the order of MV/cm. The cation of these organic salts is designed by connecting electron-donating with electron-accepting groups via a highly planar aromatic system. To improve the performance of organic …
Managing Two-Factor Authentication Setup Through Password Managers, Jonathan William Dutson
Managing Two-Factor Authentication Setup Through Password Managers, Jonathan William Dutson
Theses and Dissertations
Two-factor authentication (2FA) provides online accounts with protection against remote account compromise. Despite the security benefits, adoption of 2FA has remained low, in part due to poor usability. We explore the possibility of improving the usability of the 2FA setup process by providing setup automation through password managers. We create a proof-of-concept KeePass (a popular password manager) extension that adds browser-based automation to the 2FA setup process and conduct a 30-participant within-subjects user study to measure user perceptions about the system. Our system is found to be significantly more usable than the current manual method of 2FA setup for multiple …
Capillary Morphogenesis Gene Protein 2 (Cmg2) Mediates Matrix Protein Uptake And Is Required For Endothelial Cell Chemotaxis In Response To Multiple Vascular Growth Factors, Tsz Ming Jeremy Tsang
Capillary Morphogenesis Gene Protein 2 (Cmg2) Mediates Matrix Protein Uptake And Is Required For Endothelial Cell Chemotaxis In Response To Multiple Vascular Growth Factors, Tsz Ming Jeremy Tsang
Theses and Dissertations
Pathological angiogenesis, or new blood vessel formation, is involved in many pathologies, including cancer and serious eye diseases. While traditional anti-angiogenic therapies target vascular endothelial growth factor receptors to reduce or inhibit new vessel formation, this approach has several downsides, including unpleasant side effects and low efficacy over time. Therefore, identifying new targets to treat pathological angiogenesis is still needed. CMG2, one of the two identified anthrax toxin receptors, has been proposed as an alternative target to treat pathological angiogenesis. CMG2’s role as a cell surface receptor that mediates anthrax toxin internalization is very well documented. One physiological function for …
Bounds On Heat Transfer In The Presence Of Ekman Pumping, Benjamin Alexander Pachev
Bounds On Heat Transfer In The Presence Of Ekman Pumping, Benjamin Alexander Pachev
Theses and Dissertations
Rigorous bounds on heat transfer in rapidly rotating convection have existed for several years in the case of free-slip or stress-free boundary conditions. No-slip boundary conditions result in a phenomenon known as Ekman pumping, which significantly impacts the heat transport. A recent collaborative effort in which the author was involved significantly sharpened the bound on heat transfer in the presence of Ekman pumping. The resulting publication was targeted for an audience consisting primarily of physicists and other non-mathematicians. This work stems from the same effort, but is intended for a mathematical audience. Two additional, new results are presented that provide …
Growing Complex Networks For Better Learning Of Chaotic Dynamical Systems, David Joseph Passey Jr.
Growing Complex Networks For Better Learning Of Chaotic Dynamical Systems, David Joseph Passey Jr.
Theses and Dissertations
This thesis advances the theory of network specialization by characterizing the effect of network specialization on the eigenvectors of a network. We prove and provide explicit formulas for the eigenvectors of specialized graphs based on the eigenvectors of their parent graphs. The second portion of this thesis applies network specialization to learning problems. Our work focuses on training reservoir computers to mimic the Lorentz equations. We experiment with random graph, preferential attachment and small world topologies and demonstrate that the random removal of directed edges increases predictive capability of a reservoir topology. We then create a new network model by …
Stability Of Mhd Shock Waves, Bryn Nicole Barker
Stability Of Mhd Shock Waves, Bryn Nicole Barker
Theses and Dissertations
This thesis focuses on the study of spectral stability of planar shock waves in 2-dimensional magnetohydrodynamics. We begin with a numerical approach, computing the Lopatinski determinant and Evans function with the goal of determining if there are parameters for which viscous waves are unstable and the corresponding inviscid waves are stable. We also begin developing a method to obtain an explicit, analytical representation of the Evans function. We demonstrate the capabilities of this method with compressible Navier-Stokes and extend our results to 2-D MHD. Finally, using compressible Navier-Stokes again, we derive an energy estimate as a first step in improving …
An Actuarial Approach To Personal Injury Protection Severity, Jason Colgrove
An Actuarial Approach To Personal Injury Protection Severity, Jason Colgrove
Undergraduate Honors Theses
Insurance companies examine the risk of financial losses for their policyholders as a way to accurately price insurance policies. Within the automobile insurance sector, the frequency of crashes and the associated liabilities started to increase in late 2013 when it had been on the decline for close to a decade. The purpose of this research focuses on the possible correlated variables that could lead to a better understanding of this change. To embark on this task, we teamed up with the Society of Actuaries, Casualty Actuarial Society, and the American Property Casualty Insurance Association to obtain data regarding frequency, severity, …
Immobilization Of Copper Nanoparticles Onto Various Supports Applications In Catalysis, Anh Hoang Tu Nguyen Sorenson
Immobilization Of Copper Nanoparticles Onto Various Supports Applications In Catalysis, Anh Hoang Tu Nguyen Sorenson
Theses and Dissertations
Copper-based materials are one of the most promising catalysts for performing transformations of important organic compounds in both academic and industrial operations. However, it is challenging to consistently synthesize highly active and stable copper species as heterogeneous catalysts due to their relatively high surface energy. As a result, agglomeration usually occurs, which limits the catalytic activities of the copper species. The work presented in this dissertation shows different synthetic strategies for obtaining active and stable copper-based materials by modifying chemical/physical properties of copper nanoparticles (NPs). Emphasis is placed on discussing specific catalytic systems, including carbon-supported catalysts (monometallic and bimetallic copper-based …
The Investigation Of Functionalized Carbon Nanotubes For The Carbon Dioxide Capture And Ethane Oxidative Dehyrogenation Catalysts, Zheng Zhou
Theses and Dissertations
Carbon nanotubes (CNT) have gained interest for wide use as both support and catalyst due to the ease of uniquely tunable surface chemistry. Increasingly severe greenhouse effects have attracted attention to novel materials and technologies capable of capturing carbon dioxide (CO2). In this context, we develop a CNT based solid state amine for the CO2 capture. CNT are functionalized under various methods as a support for polymeric amines. Polyethyleneimine are physically adsorbed on CNT and are further characterized and studied for reversible CO2 capture. We obtain a high CO2 capture capacity (6.78 mmol∙g-1) for linear polyethyleneimine (LPEI) and 6.18 mmol∙g-1 …
Retiming Smoke Simulation Using Machine Learning, Samuel Charles Gérard Giraud Carrier
Retiming Smoke Simulation Using Machine Learning, Samuel Charles Gérard Giraud Carrier
Theses and Dissertations
Art-directability is a crucial aspect of creating aesthetically pleasing visual effects that help tell stories. A particularly common method of art direction is the retiming of a simulation. Unfortunately, the means of retiming an existing simulation sequence which preserves the desired shapes is an ill-defined problem. Naively interpolating values between frames leads to visual artifacts such as choppy frames or jittering intensities. Due to the difficulty in formulating a proper interpolation method we elect to use a machine learning approach to approximate this function. Our model is based on the ODE-net structure and reproduces a set of desired time samples …
Gamma-Ray Burst Afterglow Dynamics In Inhomogeneous Interstellar Media, Jacob Fields
Gamma-Ray Burst Afterglow Dynamics In Inhomogeneous Interstellar Media, Jacob Fields
Undergraduate Honors Theses
Gamma-ray bursts (GRBs) are the most luminous electromagnetic phenomena in the universe, but much remains unknown about them. Many models invoked to explain their highly variable light curves are based on complicated dynamics and interactions involving the GRB progenitor but assume simple circumstellar environments. Many long GRBs, however, show late time optical and x-ray flares that may be an indication of a much richer environment. Relativistic hydrodynamics simulations are used to study a family of initial data with a relativistic blast wave encountering a dense circumstellar shell of matter, similar to what an aging star expelling the outer layers of …
An Analysis Of Opiate Prescription For Chronic Degenerative Disease And Other Pain Syndromes, Catherine Sawyer
An Analysis Of Opiate Prescription For Chronic Degenerative Disease And Other Pain Syndromes, Catherine Sawyer
Undergraduate Honors Theses
Utilizing the National Ambulatory Medical Care Survey (NAMCS) database, this thesis explores patterns of opiate prescribing during time period from 1993 to 2016, which includes the time period when the opiate crisis was recognized in the United States and efforts begun to combat it. We analyze these patterns particularly as they relate to patients who were prescribed opiates and who were simultaneously suffering from various chronic conditions, and interactions between prescription of opiates and diagnosis of chronic conditions. We examine which demographic groups were most likely to receive opiates, and considered opiate prescription trends among patients with any pain diagnosis …
Using Logical Specifications For Multi-Objective Reinforcement Learning, Kolby Nottingham
Using Logical Specifications For Multi-Objective Reinforcement Learning, Kolby Nottingham
Undergraduate Honors Theses
In the multi-objective reinforcement learning (MORL) paradigm, the relative importance of environment objectives is often unknown prior to training, so agents must learn to specialize their behavior to optimize different combinations of environment objectives that are specified post-training. These are typically linear combinations, so the agent is effectively parameterized by a weight vector that describes how to balance competing environment objectives. However, we show that behaviors can be successfully specified and learned by much more expressive non-linear logical specifications. We test our agent in several environments with various objectives and show that it can generalize to many never-before-seen specifications.
Orientable Single-Distance Codes For Absolute Incremental Encoders, Kristian Brian Sims
Orientable Single-Distance Codes For Absolute Incremental Encoders, Kristian Brian Sims
Theses and Dissertations
Digital encoders are electro-mechanical sensors that measure linear or angular position using special binary patterns. The properties of these patterns influence the traits of the resulting encoders, such as their maximum speed, resolution, tolerance to error, or cost to manufacture. We describe a novel set of patterns that can be used in encoders that are simple and compact, but require some initial movement to register their position. Previous designs for such encoders, called absolute incremental encoders, tend to incorporate separate patterns for the functions of tracking incremental movement and determining the absolute position. The encoders in this work, however, use …
Machine Learning For Effective Parkinson's Disease Diagnosis, Brennon Brimhall
Machine Learning For Effective Parkinson's Disease Diagnosis, Brennon Brimhall
Undergraduate Honors Theses
Parkinson’s Disease is a degenerative neurological condition that affects approximately 10 million people globally. Because there is currently no cure, there is a strong motivation for research into improved and automated diagnostic procedures. Using Random Forests, a computer can effectively learn to diagnose Parkinson’s disease in a patient with high accuracy (94%), precision (95%), and recall (91%) across the data of over 2800 patients. Using similar techniques, I further determine that the most predictive medical tests relate to tremors observed in patients.
Congruences For Coefficients Of Modular Functions In Levels 3, 5, And 7 With Poles At 0, Ryan Austin Keck
Congruences For Coefficients Of Modular Functions In Levels 3, 5, And 7 With Poles At 0, Ryan Austin Keck
Theses and Dissertations
We give congruences modulo powers of p in {3, 5, 7} for the Fourier coefficients of certain modular functions in level p with poles only at 0, answering a question posed by Andersen and Jenkins and continuing work done by the Jenkins, the author, and Moss. The congruences involve a modulus that depends on the base p expansion of the modular form's order of vanishing at infinity.