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Articles 1 - 30 of 83
Full-Text Articles in Physical Sciences and Mathematics
Temperature Relaxation And Magnetically Suppressed Expansion In Strongly Coupled Ultracold Neutral Plasmas, Robert Tucker Sprenkle
Temperature Relaxation And Magnetically Suppressed Expansion In Strongly Coupled Ultracold Neutral Plasmas, Robert Tucker Sprenkle
Theses and Dissertations
Ultracold neutral plasmas provide a platform for studying transport properties in an idealized environment. In this dissertation, transport properties in a Ca$^+$/Yb$^+$ dual species ultracold neutral plasma and a Ca$^+$ magnetized ultracold neutral plasma are studied. In dual species plasmas, we study ion-ion temperature relaxation. We compare measured relaxation rates with atomistic simulations and a range of popular theories. Our work validates the assumptions and capabilities of molecular dynamic simulations and invalidates theoretical models in this regime. This work illustrates an approach for precision determinations of detailed material properties in Coulomb mixtures across a wide range of conditions. We also …
Bayesian, Frequentist, And Information Geometry Approaches To Parametric Uncertainty Quantification Of Classical Empirical Interatomic Potentials, Yonatan Kurniawan
Bayesian, Frequentist, And Information Geometry Approaches To Parametric Uncertainty Quantification Of Classical Empirical Interatomic Potentials, Yonatan Kurniawan
Theses and Dissertations
Uncertainty quantification (UQ) is an increasingly important part of materials modeling. In this paper, we consider the problem of quantifying parametric uncertainty in classical empirical interatomic potentials (IPs). Previous work based on local sensitivity analysis using the Fisher Information has shown that IPs are sloppy, i.e., are insensitive to coordinated changes of many parameter combinations. We confirm these results and further explore the non-local statistics in the context of sloppy model analysis using both Bayesian (MCMC) and Frequentist (profile likelihood) methods. We interface these tools with the Knowledgebase of Interatomic Models (OpenKIM) and study three models based on the Lennard-Jones, …
Development And Characterization Of An Underwater Acoustics Laboratory Via In Situ Impedance Boundary Measurements, Cameron Taylor Vongsawad
Development And Characterization Of An Underwater Acoustics Laboratory Via In Situ Impedance Boundary Measurements, Cameron Taylor Vongsawad
Theses and Dissertations
Modeling underwater acoustic propagation comes with a variety of challenges due to the need for proper characterization of the environmental conditions. These conditions include ever changing and complex water properties as well as boundary conditions. The BYU underwater acoustics open-air tank test-bed and measurement chain were developed to study underwater acoustic propagation within a controlled environment. It was also developed to provide ways to test and validate ocean models without the high cost associated with obtaining open ocean measurements. However, tank measurements require additional characterization of boundary conditions associated with the walls of the tank which would not be present …
An Analysis Of Two Photometric Redshift Methods And Their Uses For Finding Void Galaxies, Rochelle J. Steele
An Analysis Of Two Photometric Redshift Methods And Their Uses For Finding Void Galaxies, Rochelle J. Steele
Theses and Dissertations
An extensive survey of extragalactic objects with accurate distances is difficult to perform. Distance at that scale is commonly found with redshift and most easily identified with spectroscopic observations, which are time intensive. This is especially a concern when surveying for the elusive, possibly non-existent dwarf galaxies in the centers of voids, whose light would be so faint that a spectroscopic survey to find them would be unreasonably time consuming. Photometric methods to calculate redshift could provide a much quicker way to find distance, but the photometric methods used thus far are characterized by large errors that make them unusable …
Pentagonal Extensions Of The Rationals Ramified At A Single Prime, Pablo Miguel Rodriguez
Pentagonal Extensions Of The Rationals Ramified At A Single Prime, Pablo Miguel Rodriguez
Theses and Dissertations
In this thesis, we define a certain group of order 160, which we call a hyperpentagonal group, and we prove that every totally real D5-extension of the rationals ramified at only one prime is contained in a hyperpentagonal extension of the rationals. This generalizes a result of Doud and Childers (originally conjectured by Wong) that every totally real S3 extension of the rationals ramified at only one prime is contained in an S4 extension.
Using Facies Analysis And Reservoir Characterization Of The Albian-Cenomanian Nanushuk Formation To Assist In Better Understanding Interactions Between Shoreface, Deltaic, And Fluvial Systems On The North Slope, Alaska, Andrea Smoot
Theses and Dissertations
The Albian-Cenomanian Nanushuk Formation located on the North Slope of Alaska is the result of fluvial, deltaic, and shoreface processes and has been the focus of recent petroleum exploration activity in the Colville Basin. The Nanushuk and underlying Torok formations together contain an estimated 8.7 billion barrels of oil and 25 trillion cubic feet of natural gas reserves within the resource-rich North Slope. The Nanushuk Formation is composed of sediment sourced from the Chukotka Peninsula to the west and deposited axially within the Colville Basin. High sedimentation rates led to rapid progradation of shoreface and deltaic systems, which effectively filled …
Minimizer Of A Free Boundary Problem, Mingyan Zhao
Minimizer Of A Free Boundary Problem, Mingyan Zhao
Theses and Dissertations
We study a free boundary problem with initial data given on three-dimensional cones. In particular, we study when the free boundary is allowed to pass through the vertex of the cone, which depends on the cone’s slope, determined by a parameter c. With a mix of analytical and computational methods, we show that the free boundary may pass through the vertex of the cone when c ≤ 0.43.
Deep Parameter Selection For Classic Computer Vision Applications, Michael Whitney
Deep Parameter Selection For Classic Computer Vision Applications, Michael Whitney
Theses and Dissertations
A trend in computer vision today is to retire older, so-called "classic'' methods in favor of ones based on deep neural networks. This has led to tremendous improvements in many areas, but for some problems deep neural solutions may not yet exist or be of practical application. For this and other reasons, classic methods are still widely used in a variety of applications. This paper explores the possibility of using deep neural networks to improve these older methods instead of replace them. In particular, it addresses the issue of parameter selection in these algorithms by using a neural network to …
Modeling A Human Family Network, Rebecca Jo Flores
Modeling A Human Family Network, Rebecca Jo Flores
Theses and Dissertations
We propose a model that generates a family network based on real-world family network data. We use this model to study the extent to which distances to union and the number of children characterize family networks. To determine how accurate our model is we use persistent homology to identify and compare the structure of our modeled family networks to real-world family networks. To accomplish this, we introduce the notion of a network's persistence curve, which encodes the network's set of persistence intervals. Using the bottleneck distance allows us to measure the difference in the homological structure between any pair of …
Electrocatalytic Oxidation Of Carbohydrates Via Surface Immobilized Viologen, Dallin D.V. Scott
Electrocatalytic Oxidation Of Carbohydrates Via Surface Immobilized Viologen, Dallin D.V. Scott
Theses and Dissertations
Earths most abundant biomolecules, carbohydrates, offer tremendous potential forelectricity production. Carbohydrate fuel cells are electrical fuel cells that can harvest the stored electrons in carbohydrates and offer a cheap and efficient method that could help solve growing energy demands, while providing a renewable green energy source. Viologen-mediated carbohydrate fuel cells have demonstrated the ability to accelerate carbohydrate oxidation while decreasing partial or incomplete oxidation products reducing the electricity production. Subsequent studies suggested polymeric viologen compounds could improve the efficiency by increasing the local concentration of viologen. This thesis presents the utility of surface-immobilized viologen mediators for the oxidation of simple …
Galectin-1: Development Of A Novel Protein Therapy For Lgmd2b, Mary Lorena Vallecillo Munguia
Galectin-1: Development Of A Novel Protein Therapy For Lgmd2b, Mary Lorena Vallecillo Munguia
Theses and Dissertations
Muscular dystrophies are a heterogeneous group of genetic diseases that involve mutations in genes leading to progressive muscular weakness. Limb-Girdle Muscular Dystrophy 2B (LGMD2B) is a subset of muscular dystrophy caused by mutations in the DYSF gene, which encodes for dysferlin protein and has an incidence of 1/100,000-1/200,000 people, or 1/300 people of Libyan Jewish descent. Since there is no effective treatment that can cure or reverse effects of LGMD2B once diagnosed, our goal is to investigate and develop a protein therapy that mitigates effects of this disease in patients. Galectin-1 (Gal-1) is a small, soluble 14.5 kDa protein with …
Quantitative Stem: A Method For Measuring Temperature And Thickness Effects On Thermal Diffuse Scattering Using Stem/Eels, And For Testing Electron Scattering Models, Paul S. Minson
Theses and Dissertations
In the last two decades, advances in the dark field detectors and microscopes of scanning transmission electron microscopy (STEM) have inspired a resurgence of interest in quantitative STEM analysis. One promising avenue is the use of STEM as a nanothermometric probe. In this application, thermal diffuse scattering, captured by a CCD camera or an annular dark field detector, acts as an indirect measurement of the specimen temperature. One challenge with taking such a measurement is achieving adequate sensitivity to quantify a change in scattered electron signal on the order of 1% or less of the full electron beam. Another difficulty …
Microwave-Promoted Iminyl Radical Fragmentations And The Total Synthesis Of Yaku'amide A And Its Simplified Analogues, Concordia Lo
Microwave-Promoted Iminyl Radical Fragmentations And The Total Synthesis Of Yaku'amide A And Its Simplified Analogues, Concordia Lo
Theses and Dissertations
The first project in this dissertation describes the use of microwave-promoted iminyl radical fragmentations to form functionalized nitriles. Nitrogen-centered radical chemistry is a useful tool to construct valuable C-N bonds commonly found in pharmaceuticals and biologically active molecules. Classically, these reactions require the use of toxic initiators and propagators. Iminyl radical chemistry has been gaining momentum as a means of avoiding these harsh conditions. This project utilizes the fragmentation of cyclic iminyl radicals via irradiation of O-phenyl oxime ethers to produce a synthetically useful nitrile tethered to an alkyl radical in the absence of metal catalysts and redox chemistry. The …
Field Investigations And Numerical Modeling Of Earthquake And Tsunami Risk At Four Vulnerable Sites In Indonesia, Claire E. Ashcraft
Field Investigations And Numerical Modeling Of Earthquake And Tsunami Risk At Four Vulnerable Sites In Indonesia, Claire E. Ashcraft
Theses and Dissertations
Maps and models of seismic and tsunami risk are constructed from a variety of measurements taken in Indonesia, which have the potential to reduce loss of life and infrastructure. The first study uses the multichannel analysis of surface waves (MASW) method to calculate the time-averaged shear wave velocity to 30 m depth (Vs30). These measurements were taken at 58 sites in the city of Pacitan, Java and on the islands of Lombok, Ambon, and the Banda Islands. Vs30 calculations are compared with local geologic maps to extrapolate site class for locations not measured directly. Site class maps are then compared …
Totally P-Adic Numbers Of Degree 4, Melissa Janet Ault
Totally P-Adic Numbers Of Degree 4, Melissa Janet Ault
Theses and Dissertations
In this thesis, we extend results of Emerald Stacy to compute an upper bound on the minimal height of a totally p-adic algebraic integer of degree 4 independent of p. We also compute actual values of the minimal height of a totally p-adic algebraic integer of degree 4 for small primes p.
Non-Linear Optical Characterization Of Stressed Materials, Kaylee N. Rellaford
Non-Linear Optical Characterization Of Stressed Materials, Kaylee N. Rellaford
Theses and Dissertations
Interactions between materials, their surfaces, and applied stresses are involved in every man-made construction in the world. Therefore, finding ways to interact without altering inherent properties of materials is of great interest. Surface spectroscopies, including second harmonic generation (SHG) and sum frequency generation (SFG), are inherently noninvasive testing methods. Both SHG and SFG are well-developed techniques that can be used in various applications including the characterization of material state. Both of these techniques allow for a noninvasive analysis of various materials, such as metals and polymers. We have used SHG as a method to characterize the change in signal strength …
Zeros Of A Two-Parameter Family Of Harmonic Trinomials, David Work
Zeros Of A Two-Parameter Family Of Harmonic Trinomials, David Work
Theses and Dissertations
This thesis studies complex harmonic polynomials of the form $f(z) = az^n + b\bar{z}^k+z$ where $n, k \in \mathbb{Z}$ with $n > k$ and $a, b > 0$. We show that the sum of the orders of the zeros of such functions is $n$ and investigate the locations of the zeros, including whether the zeros are in the sense-preserving or sense-reversing region and a set of conditions under which zeros have the same modulus. We also show that the number of zeros ranges from $n$ to $n+2k+2$ as long as certain criteria are met.
Computing Agent Competency In First Order Markov Processes, Xuan Cao
Computing Agent Competency In First Order Markov Processes, Xuan Cao
Theses and Dissertations
Artificial agents are usually designed to achieve specific goals. An agent's competency can be defined as its ability to accomplish its goals under different conditions. This thesis restricts attention to a specific type of goal, namely reaching a desired state without exceeding a tolerance threshold of undesirable events in a first-order Markov process. For such goals, the state-dependent competency for an agent can be defined as the probability of reaching the desired state without exceeding the threshold and within a time limit given an initial state. The thesis further defines total competency as the set of state-dependent competency relationships over …
Fabrication Of Advanced Materials For Chromatography, Sample Preparation, And Separations, And Accompanying Material Characterization, Dhananjay I. Patel
Fabrication Of Advanced Materials For Chromatography, Sample Preparation, And Separations, And Accompanying Material Characterization, Dhananjay I. Patel
Theses and Dissertations
My dissertation primarily focuses on the fabrication of materials for solid phase microextraction (SPME) and separation devices. In my first project, I used direct current magnetron sputtering (DCMS) to prepare sputtered silicon coatings on fused silica fibers. These fibers were then subjected to the chemical vapor deposition of 6-phenyhexylsilane (6-PH) as a stationary phase. Six different types of fibers were made using two different throw distances (4 cm and 20 cm) and three different silicon thicknesses (0.5, 1.8, and 2.8 µm). These coatings were characterized by time-of-flight secondary ion mass spectrometry (ToF-SIMS), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), …
Weak Cayley Table Groups Of Crystallographic Groups, Rebeca Ann Paulsen
Weak Cayley Table Groups Of Crystallographic Groups, Rebeca Ann Paulsen
Theses and Dissertations
Let G be a group. A weak Cayley table isomorphism $\phi$: G $\rightarrow$ G is a bijection satisfying two conditions: (i) $phi$ sends conjugacy classes to conjugacy classes; and (ii) $\phi$(g1)$\phi$(g2) is conjugate to $\phi$(g1g2) for all g1, g2 in G. The set of all such mappings forms a group W(G) under composition. We study W(G) for fifty-six of the two hundred nineteen three-dimensional crystallographic groups G as well as some other groups. These fifty-six groups are related to our previous work on wallpaper groups.
Chemical And Physical Weathering Rates Of Basaltic Volcanic Regions: Utilizing Space In Place Of Time In The Hawaiian Archipelago, Benjamin Clyde Barton
Chemical And Physical Weathering Rates Of Basaltic Volcanic Regions: Utilizing Space In Place Of Time In The Hawaiian Archipelago, Benjamin Clyde Barton
Theses and Dissertations
With large populations living in tropical regions of the world with volcanic substrates, understanding basalt weathering processes is vital. The Hawaiian Islands are an excellent natural analogue to study chemical weathering rates due to a uniform bedrock (basalt), large variations in rainfall, and varying ages across the islands. Laterite weathering profiles (LWP) develop over time through chemical weathering, where LWP thickness is influenced by many factors, including precipitation and time. Using the rapid, non-invasive horizontal-to-vertical spectral ratio (HVSR) method, LWP thicknesses can be estimated to constrain chemical weathering rates. Studying the laterite weathering profiles developed from basaltic bedrock of varying …
Modeling User Relationships In Online Communities Of Creators, Berkeley Andrus
Modeling User Relationships In Online Communities Of Creators, Berkeley Andrus
Theses and Dissertations
Those who study creativity, especially from a computational perspective, have long understood the role of social influence in the creative process. This has motivated many efforts to simulate social mechanics in artificial creative systems. However, these simulations have often replicated generic or assumed human behaviors rather than specific anthropological data. In this work we take a more focused approach by quantitatively measuring interactions between creators in online social communities and replicating observed phenomena in a simulated environment. The primary contributions of this thesis are 1) defining quantitative metrics for comparing human and simulated social networks of creators, 2) providing social …
Exploring Improvements To The Convergence Of Reconstructing Historical Destructive Earthquakes, Kameron Lightheart
Exploring Improvements To The Convergence Of Reconstructing Historical Destructive Earthquakes, Kameron Lightheart
Theses and Dissertations
Determining risk to human populations due to natural disasters has been a topic of interest in the STEM fields for centuries. Earthquakes and the tsunamis they cause are of particular interest due to their repetition cycles. These cycles can last hundreds of years but we have only had modern measuring instruments for the last century or so which makes analysis difficult. In this document, we explore ways to improve upon an existing method for reconstructing earthquakes from historical accounts of tsunamis. This method was designed and implemented by Jared P Whitehead's research group over the last 5 years. The issue …
Determining The Anthropogenic Effects On Eutrophication Of Utah Lake Since European Settlement Using Multiple Geochemical Approaches, Richard Ronald Rawle Williams
Determining The Anthropogenic Effects On Eutrophication Of Utah Lake Since European Settlement Using Multiple Geochemical Approaches, Richard Ronald Rawle Williams
Theses and Dissertations
Recent urbanization of Utah Valley, Utah, has highlighted the impacts of anthropogenically-driven eutrophication of Utah Lake, which may lead to more frequent harmful algal blooms. To examine changes in trophic state, three freeze cores were taken from Utah Lake (Goshen Bay, Provo Bay, and near the Provo Boat Harbor) to examine the extent of eutrophication since European settlement. 210Pb and 137Cs chronologies were constructed for all three cores, although due to low supported 210Pb in the Provo Boat Harbor core, an additional pollen analysis was performed. Lower juniper pollen counts in addition to higher POACEAE (grasses and cereals) counts above …
Beware Of Ips In Sheep's Clothing: Measurement And Disclosure Of Ip Spoofing Vulnerabilities, Alden Douglas Hilton
Beware Of Ips In Sheep's Clothing: Measurement And Disclosure Of Ip Spoofing Vulnerabilities, Alden Douglas Hilton
Theses and Dissertations
Networks not employing destination-side source address validation (DSAV) expose themselves to a class of pernicious attacks which could be prevented by filtering inbound traffic purporting to originate from within the network. In this work, we survey the pervasiveness of networks vulnerable to infiltration using spoofed addresses internal to the network. We issue recursive Domain Name System (DNS) queries to a large set of known DNS servers world-wide using various spoofed-source addresses. In late 2019, we found that 49% of the autonomous systems we tested lacked DSAV. After a large-scale notification campaign run in late 2020, we repeated our measurements in …
Reducing The Manual Annotation Effort For Handwriting Recognition Using Active Transfer Learning, Eric Burdett
Reducing The Manual Annotation Effort For Handwriting Recognition Using Active Transfer Learning, Eric Burdett
Theses and Dissertations
Handwriting recognition systems have achieved remarkable performance over the past several years with the advent of deep neural networks. For high-quality recognition, these models require large amounts of labeled training data, which can be difficult to obtain. Various methods to reduce this effort have been proposed in the realms of active and transfer learning, but not in combination. We propose a framework for fitting new handwriting recognition models that joins active and transfer learning into a unified framework. Empirical results show the superiority of our method compared to traditional active learning, transfer learning, or standard supervised training schemes.
Turn Of Phrase: Contrastive Pre-Training For Discourse-Aware Conversation Models, Roland Laboulaye
Turn Of Phrase: Contrastive Pre-Training For Discourse-Aware Conversation Models, Roland Laboulaye
Theses and Dissertations
Understanding long conversations requires recognizing a discourse flow unique to conversation. Recent advances in unsupervised representation learning of text have been attained primarily through language modeling, which models discourse only implicitly and within a small window. These representations are in turn evaluated chiefly on sentence pair or paragraph-question pair benchmarks, which measure only local discourse coherence. In order to improve performance on discourse-reliant, long conversation tasks, we propose Turn-of-Phrase pre-training, an objective designed to encode long conversation discourse flow. We leverage tree-structured Reddit conversations in English to, relative to a chosen conversation path through the tree, select paths of varying …
Exploring Non-Functional Coupling Between Subsystems, Matt Pope
Exploring Non-Functional Coupling Between Subsystems, Matt Pope
Theses and Dissertations
Many software systems depend on other systems to function correctly or are themselves composed of interdependent subsystems. In that context, behavioral changes in a dependency may have consequences for a dependent subsystem. This includes changes to non-functional properties such as latency or availability. In this paper we use the term non-functional coupling to mean the extent to which a subsystem is affected by changes to non-functional properties in a dependency. We argue that non-functional coupling has implications for the maintainability, reliability and performance of an overall system. We also explore the extent to which various engineering techniques used in interaction …
Decision Based Learning Course Design & Implementation For Introductory Statistics, Austin Heath
Decision Based Learning Course Design & Implementation For Introductory Statistics, Austin Heath
Undergraduate Honors Theses
Researchers in multiple industries (biomedicine, engineering, etc.) cite the selection of an appropriate statistical test as a common problem. Experts draw on a framework of conceptual and procedural knowledge to navigate when to use statistical methods. Students also struggle determining the correct statistical method to use for a given research question. This is because they lack the opportunity to practice recognizing a host of features in each research question that provide clues for experts as to which method is most appropriate. “Decision Based Learning” (DBL) is a teaching method designed to help teachers and students address this struggle. In this …
A Usability Study Of Fido2 Roaming Software Tokens As A Password Replacement, Brian Rasmussen
A Usability Study Of Fido2 Roaming Software Tokens As A Password Replacement, Brian Rasmussen
Theses and Dissertations
The use of passwords for user authentication has significant shortcomings. As society becomes more dependent on the internet and web services, we need to find a replacement authentication method that users are willing to use. WebAuthn is one potential technology for password replacement. Recent studies have shown that users enjoy the usability of WebAuthn and hardware tokens as a password replacement but don't want to carry them around. Meanwhile, little to no research involves the use of software tokens. I carried out a user study of WebAuthn and roaming software tokens when used as a password replacement. We were able …