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University of North Florida

2020

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Articles 1 - 26 of 26

Full-Text Articles in Physical Sciences and Mathematics

Uniform Random Variate Generation With The Linear Congruential Method, Joseph Free Jul 2020

Uniform Random Variate Generation With The Linear Congruential Method, Joseph Free

PANDION: The Osprey Journal of Research and Ideas

This report considers the issue of using a specific linear congruential generator (LCG) to create random variates from the uniform(0,1) distribution. The LCG is used to generate multiple samples of pseudo-random numbers and statistical computation techniques are used to assess whether those samples could have resulted from a uniform(0,1) distribution. Source code is included with this report in the appendix along with annotations.


Investigation Of The Obscure Spin State Of Ti-Doped Cdse, J. Dimuna, T. Boyett, I. Miotkowski, A. K. Ramdas, T. Pekarek, J. T. Haraldsen Apr 2020

Investigation Of The Obscure Spin State Of Ti-Doped Cdse, J. Dimuna, T. Boyett, I. Miotkowski, A. K. Ramdas, T. Pekarek, J. T. Haraldsen

Showcase of Osprey Advancements in Research and Scholarship (SOARS)

Using computational and experimental techniques, we examine the nature of the 2+ oxidation of Ti-doped CdSe. Through stoichiometry and confirmed through magnetization measurements, the weakly-doped material of Cd1-xTixSe (x = 0.0043) shows the presence of a robust spin-1 magnetic state of Ti, which is indicative of a 2+ oxidation state. Given the obscure nature of the Ti2+ state, we investigate the electronic and magnetic states using density functional theory. Using a generalized gradient approximation with an onsite potential, we determine the electronic structure, magnetic moment density, and optical properties for a supercell of CdSe with an ultra-low concentration of Ti. …


Iceact Monitoring And Data Analysis, Andre Sierra Alderete, John W. Hewitt, Warren Huelsnitz Apr 2020

Iceact Monitoring And Data Analysis, Andre Sierra Alderete, John W. Hewitt, Warren Huelsnitz

Showcase of Osprey Advancements in Research and Scholarship (SOARS)

The goal of the IceACT project is to establish an array of small ACTs deployed at the South Pole for neutrino detection, CR composition studies and high energy gamma ray detection. The IceCube Neutrino Observatory at the South Pole has detected these massless subatomic particles called neutrinos. These high-energy astronomical messengers provide us information to investigate the most violent astrophysical sources: events like exploding stars, gamma-ray bursts, and cataclysmic phenomena involving black holes and neutron stars. In particular, these neutrinos have no charge, and can travel across the universe without being scattered by interstellar magnetic fields. The main background for …


Predator-Prey Model With Herding Behavior And Hunting Quota, Randy Lee, Mahbubar Rahman Phd Apr 2020

Predator-Prey Model With Herding Behavior And Hunting Quota, Randy Lee, Mahbubar Rahman Phd

Showcase of Osprey Advancements in Research and Scholarship (SOARS)

The Lotka-Volterra predator-prey model is widely studied and used in many disciplines such as biology, ecology and economics. It is used to describe the growth and coexistence of two interacting populations. The model consists of a pair of first-order nonlinear differential equations. In this paper, we studied steady states, stability of steady states, existence of limit cycles, and bifurcation behavior of the predator-prey model by modifying the existing model with hunting quota. We also illustrated our results with numerical simulations.


Insights From The Influx Of Prescription Painkillers In Northeast Florida: A Retrospective Analysis, Joseph Free, Michelle Dedeo Apr 2020

Insights From The Influx Of Prescription Painkillers In Northeast Florida: A Retrospective Analysis, Joseph Free, Michelle Dedeo

Showcase of Osprey Advancements in Research and Scholarship (SOARS)

The opioid epidemic has had, and will have, long-lasting ramifications in the United States. To better understand its impact in the Northeast Florida, this research seeks to identify relationships between hydro- and oxycodone pill concentration at the county and zip code levels and socio-economic factors such as average adjusted gross income and opioid related mortality. This project utilizes time series, regression, and GIS methods to examine local opioid saturation and has led to the development of an interactive Tableau dashboard which allows users to view opioid saturation at various levels of granularity. This analysis is made possible by longitudinal data …


Understanding The Magnetic Interactions Of The Zig-Zag Honeycomb Lattice: Application To Rucl3, Evan Wilson, Jason T. Haraldsen Apr 2020

Understanding The Magnetic Interactions Of The Zig-Zag Honeycomb Lattice: Application To Rucl3, Evan Wilson, Jason T. Haraldsen

Showcase of Osprey Advancements in Research and Scholarship (SOARS)

The new field of Dirac quantum matter has produced a lot of interesting theories and materials, especially in the dynamics of magnetic materials. One such material is RuCl3, which is a S = 1/2 zigzag honeycomb lattice. Through inelastic neutron scattering, this material has demonstrated spin waves with an energy scale of 1.5-8.0 meV. According to literature, RuCl3 may be the realization of a new theoretical phase of matter called a spin liquid. This materials seems to fit the profile and has been investigated using a Kitaev model. In this study, we re-examine the data for RuCl3 using a standard …


Extended Gamma Analysis Of Snr G330.2 + 1.0, Abagael Barba, John W. Hewitt Apr 2020

Extended Gamma Analysis Of Snr G330.2 + 1.0, Abagael Barba, John W. Hewitt

Showcase of Osprey Advancements in Research and Scholarship (SOARS)

Analyzing gamma rays is an important aspect of modern astronomy and astrophysics, for they are the most powerful bands of energy on the electromagnetic spectrum. Comprehending gamma rays allows for deeper understanding of countless phenomena within our universe, such as cosmic rays. Cosmic rays are high energy particles thought to be formed via extremely violent explosions within our universe. These accelerated particles mirror conditions present in a supernova. A supernova is what occurs when a star at least 8 times as massive as our sun reaches the end of its lifespan and bursts. These explosions are the most powerful events …


Understanding The Spin-Glass State Through The Magnetic Properties Of Mn-Doped Znte, A. Alcantara, S. Barrett, D. Matev, I. Miotkowski, A. K. Ramdas, T. Pekarek, J. T. Haraldsen Apr 2020

Understanding The Spin-Glass State Through The Magnetic Properties Of Mn-Doped Znte, A. Alcantara, S. Barrett, D. Matev, I. Miotkowski, A. K. Ramdas, T. Pekarek, J. T. Haraldsen

Showcase of Osprey Advancements in Research and Scholarship (SOARS)

Magnetic measurements on the spin-glass behavior in the bulk II-VI diluted magnetic semiconductor (DMS) ZnMnTe were made on two crystals of concentrations x = 0.43 and 0.55 taken from the same boule. Magnetization and density functional theory studies have shown paramagnetic behavior in both samples between 30 and 400 K. Below 30 K, there is a prominent peak at Tc = 15 and 23.6 K for concentrations x = 0.43 and 0.55, respectively. The splitting of the field cooled (FC) and zero field cooled (ZFC) data below this peak is indicative of a transition to a spin-glass state at low …


Identification Of Histone H4-Based Peptoids As Inhibitors Of Prmt1, Megan Demart, Molly Dubose, Sarah Mann, Corey Causey Phd, Bryan Knuckley Phd Apr 2020

Identification Of Histone H4-Based Peptoids As Inhibitors Of Prmt1, Megan Demart, Molly Dubose, Sarah Mann, Corey Causey Phd, Bryan Knuckley Phd

Showcase of Osprey Advancements in Research and Scholarship (SOARS)

Protein Arginine Methyltransferases (PRMTs) are a family of 11 mammalian enzymes characterized by the post-translational methylation of arginine residues in the histone tail. The majority of the 11 members of the PRMT family are divided into two main types, Type I and Type II. PRMT1, the major Type I isozyme, catalyzes the formation of asymmetrically dimethylated arginine (ADMA). PRMT1 activates transcription of cancer genes. Peptoids, or poly-N-substituted glycine’s are a class of oligomers whose side chains are appended to the nitrogen atom of the peptide backbone rather than the alpha carbon. Kinetic parameters were conducted for both peptide and peptoid …


Game Theory Based Distributed Coordination With Multi-Agent Reinforcement Learning, Charlotte M. Morrison Apr 2020

Game Theory Based Distributed Coordination With Multi-Agent Reinforcement Learning, Charlotte M. Morrison

Showcase of Osprey Advancements in Research and Scholarship (SOARS)

We study the problem of automated object manipulation using two arms of a Baxter robot. The robot uses a novel multi-agent reinforcement learning strategy to learn how to complete the task without any prior experience. It learns what actions to take by storing its interactions with the environment and uses these experiences to create a policy that guides future actions. Each of Baxter’s arms is modeled as an independent agent that can move and learn separately from the other. Each arm learns independent policies (i.e., environment state to robot action mapping) about how to best move in order to complete …


Embedding Graphs On Surfaces And Graph Minors, Tracy Leung, Mya Salas, Dylan Wilson Apr 2020

Embedding Graphs On Surfaces And Graph Minors, Tracy Leung, Mya Salas, Dylan Wilson

Showcase of Osprey Advancements in Research and Scholarship (SOARS)

A planar graph is a graph that can be drawn in such a way in the plane, so that no edges cross each other. In other words, it is a graph that can be embedded in the plane. We discuss the conditions that make a graph embeddable on a sphere with k handles. Then, using vertex deletions and edge contractions, which produce graph minors, we examine if a graph is minimally nonembeddable on a surface. To conclude, we discuss an important result, that the set of minimally nonembeddable graphs on a surface is finite.


Simulation Environment For Object Manipulation With Soft Robots In Shared Autonomy, Devin Hunter, Fabio Stroppa, Allison Okamura Apr 2020

Simulation Environment For Object Manipulation With Soft Robots In Shared Autonomy, Devin Hunter, Fabio Stroppa, Allison Okamura

Showcase of Osprey Advancements in Research and Scholarship (SOARS)

The robots of today have grown to be of much more significant use than their predecessors. Robots are now being used in industries outside of the factory setting which can be seen primarily in the medical, transportation, and social fields. With robots taking on all of these new roles within our society, the establishment of robust human-robot collaboration is crucial in order for robots to be able to successfully complete desired tasks without becoming a hinderance to nearby humans. We explored this concept by implementing a shared-autonomy algorithm named MBSA (Motion Based Smart Assistance) to a soft robot simulation and …


Magnetic Properties Of Mbe Grown La1/3y1/3sr1/3mno3 Thin Films And Superlattices, W. A. Ruiz, C. Kengle, J. Payne, D. Brown, W. P. Warusawithana, T. M. Pekarek Apr 2020

Magnetic Properties Of Mbe Grown La1/3y1/3sr1/3mno3 Thin Films And Superlattices, W. A. Ruiz, C. Kengle, J. Payne, D. Brown, W. P. Warusawithana, T. M. Pekarek

Showcase of Osprey Advancements in Research and Scholarship (SOARS)

We have investigated the magnetic properties of thin films related to the standard CMR system La2/3Sr1/3MnO3 where Y substituted for 50% of the La atoms. These La1/3Y1/3Sr1/3MnO3 films were grown as a random alloy where La, Y, and Sr atoms randomly occupied the A-site or as a superlattice where each unit-cell-thick layer stacked along the crystallographic (001) direction contained only one of the atoms La, Y, and Sr occupying the A-site. One of the key magnetic features of La2/3Sr1/3MnO3 is a prominent ferromagnetic transition near 350 K. We find the substitution of La with Y suppresses this ferromagnetic transition in …


Spin-Glass Ordering In The Diluted Magnetic Semiconductor Zn1-Xmnxte, S. Barrett, T. M. Pekarek Apr 2020

Spin-Glass Ordering In The Diluted Magnetic Semiconductor Zn1-Xmnxte, S. Barrett, T. M. Pekarek

Showcase of Osprey Advancements in Research and Scholarship (SOARS)

Magnetic measurements on the spin-glass behavior in the bulk II-VI diluted magnetic semiconductor (DMS) ZnMnTe were made on two crystals of concentrations x = 0.43 and 0.55 taken from the same boule. Magnetization and density functional theory studies have shown paramagnetic behavior in both samples between 30 and 400 K. Below 30 K, there is a prominent peak at Tc = 15 and 23.6 K for concentrations x = 0.43 and 0.55, respectively. The splitting of the field cooled (FC) and zero field cooled (ZFC) data below this peak is indicative of a transition to a spin-glass state at low …


Investigating The Substrate Specificity Of Prmt1 Using A Plate Based Screening Method, Tina Sawatzky, Sarah Mann, Bryan Knuckley Apr 2020

Investigating The Substrate Specificity Of Prmt1 Using A Plate Based Screening Method, Tina Sawatzky, Sarah Mann, Bryan Knuckley

Showcase of Osprey Advancements in Research and Scholarship (SOARS)

Enzymes are biological catalysts that speed up the rate of a reaction by lowering the activation energy and converting substrate (reactant) to product more expeditiously. Enzymes have a high degree of specificity and will only catalyze selective reactions by targeting particular substrates. In mammals, there exists a family of 11 enzymes, PRMT’s (Protein Arginine Methyl transferase), that target protein arginine for post translational methylation on the guanidino nitrogen of the residue. They occur naturally as Type I, II and III and can administer asymmetric di-methylation (ADMA), symmetric dimethylation (SDMA) and monomethylation, respectively. The focal point of this project is to …


Tournaments And A Fibonacci Link, Michael Long, Daniela Genova Apr 2020

Tournaments And A Fibonacci Link, Michael Long, Daniela Genova

Showcase of Osprey Advancements in Research and Scholarship (SOARS)

Round robin tournaments are a type of directed graphs with applications to athletic competitions and transportation logistics. The presentation begins with a brief series of informative theorems and properties of directed graphs, which are imperative to our understanding of the properties that make directed graphs (and, subsequently, round robin tournaments) uniquely interesting. We then present a number of results about the properties of tournaments (defined as a complete directed graph), including transitivity–a relatively uncommon property used to determine domination in a round robin tournament–and connectivity, which can most often be seen in determining means of transportation between any two locations. …


Electronic And Magnetic Order As A Function Of Doping In Mixed-Valent La1-Xsrxmn03 Thin Films, James Payne, Dakota Brown, Calleigh Brannan, Tom Pekarek, Maitri Warusawithana Apr 2020

Electronic And Magnetic Order As A Function Of Doping In Mixed-Valent La1-Xsrxmn03 Thin Films, James Payne, Dakota Brown, Calleigh Brannan, Tom Pekarek, Maitri Warusawithana

Showcase of Osprey Advancements in Research and Scholarship (SOARS)

The rich phase diagram in mixed-valent manganites has been intensely studied in bulk crystals as a function of chemical doping. Here we study the effect of doping in La1-xSrxMnO3 thin films by varying the Sr/La ratio between samples. These thin films are grown using ozone assisted molecular beam epitaxy with carefully controlled stoichiometry for a range of doping from x = 0.0 to x = 0.5. Our electronic measurements reveal a crossover from a Mott insulator to a metallic ground state as x is increased. In the metallic ground state we observe a metal-to-insulator transition coincident with a ferromagnetic-to-paramagnetic ordering …


Block Designs, Lucien Poulin, Daniela Genova Apr 2020

Block Designs, Lucien Poulin, Daniela Genova

Showcase of Osprey Advancements in Research and Scholarship (SOARS)

Block designs are a type of combinatorial structures that can be used to model many different types of problems ranging from experimental design to computer software testing. They can be used to construct schemes that ensure complete optimization and efficiency of the given experiment. We focus mainly on Steiner and Kirkman triple systems, as well as, on different ways for constructing block designs. Well known results in combinatorics such as Fisher’s inequality and Kirkman’s schoolgirl problem are also discussed.


Reduced Dimensionality Effects In Ferromagnetic Behavior In La1-Xsrxmno3, C. A. Brennan, M. P. Warusawithana, J. Payne, D. Brown, T. M. Pekarek Apr 2020

Reduced Dimensionality Effects In Ferromagnetic Behavior In La1-Xsrxmno3, C. A. Brennan, M. P. Warusawithana, J. Payne, D. Brown, T. M. Pekarek

Showcase of Osprey Advancements in Research and Scholarship (SOARS)

We study the magnetic properties of La1-xSrxMnO3 samples for concentrations x, 0 ≤ x ≤ 0.5. An analysis is done to accurately determine the transition temperature or critical temperature. Magnetic phase diagrams showing the various concentrations at different temperatures will be determined for our thin films. Using the phase diagrams for both bulk and thin film materials can show how reducing the dimensionality from the third dimension to approaching the second-dimension affects the phase diagram.


Improving Photon Number Resolution In Superconducting Nanowire Single-Photon Detectors With Integrated Impedance Tapers, Bladimiro E. Valbuena, Daniel F. Santavicca Apr 2020

Improving Photon Number Resolution In Superconducting Nanowire Single-Photon Detectors With Integrated Impedance Tapers, Bladimiro E. Valbuena, Daniel F. Santavicca

Showcase of Osprey Advancements in Research and Scholarship (SOARS)

Simulations are run to optimize the ability to resolve the number of photons detected from the pulse height by a Superconducting Nanowire Single-Photon Detector (SNSPD). This is set up in a manner that features an impedance-matching transmission line taper that provides a characteristic impedance which transitions from kΩ to 50 Ω, with the taper providing an effective load impedance that outputs pulses with not only larger amplitudes but also showed a distinct separation for multi-photon events. The first part of this project tries to computationally match the experimental results obtained by our collaborators at MIT. Once these results are achieved, …


Cenozoic Vertebrate Biostratigraphy Of South Carolina, Usa, And Additions To The Fauna, L. Barry Albright Dr., Albert Sanders Dr., Robert Weems, David Cicimurri, James Knight Jan 2020

Cenozoic Vertebrate Biostratigraphy Of South Carolina, Usa, And Additions To The Fauna, L. Barry Albright Dr., Albert Sanders Dr., Robert Weems, David Cicimurri, James Knight

Showcase of Faculty Scholarly & Creative Activity

Although South Carolina has not typically been considered a state yielding a wealth of vertebrate paleontological resources, study of its fossils, particularly those from the famous “Ashley River phosphate beds” near Charleston, played a significant role in the early history of vertebrate paleontology as a scientific discipline in North America. Long overshadowed by the exceptionally rich Cenozoic record from Florida, renewed efforts in South Carolina over the last three decades have resulted in a wealth of new data from sites that rival, and in some cases surpass, any others along the US Atlantic Coastal Plain. With increasing study of these …


University Of North Florida Environmental Center Annual Report 2020, James W. Taylor, Erin Largo-Wight, Kelly Rhoden Jan 2020

University Of North Florida Environmental Center Annual Report 2020, James W. Taylor, Erin Largo-Wight, Kelly Rhoden

Annual Reports

2020 Annual Report of the Environmental Center at the University of North Florida


A Two-Stage Design For Comparing Binomial Treatments With A Standard, Cecelia K. Schmidt Jan 2020

A Two-Stage Design For Comparing Binomial Treatments With A Standard, Cecelia K. Schmidt

UNF Graduate Theses and Dissertations

We propose a method for comparing success rates of several populations among each other and against a desired standard success rate. This design is appropriate for a situation in which all experimental treatments have only two outcomes that can be considered “success”and “failure” respectively. The goal is to identify which treatment has the highest rate of success that is also higher than the desired standard. The design combines elements of both hypothesis testing and statistical selection. At the first stage, if none of the samples have a number of successes above the appropriate standard for the design, the experiment is …


The Subconstituent Algebra Of A Hypercube, Jared B. Billet Jan 2020

The Subconstituent Algebra Of A Hypercube, Jared B. Billet

UNF Graduate Theses and Dissertations

We study the hypercube and the associated subconstituent algebra. Let Q_D denote the hypercube with dimension D and let X denote the vertex set of Q_D. Fix a vertex x in X. We denote by A the adjacency matrix of Q_D and by A* = A*(x) the diagonal matrix with yy-entry equal to D − 2i, where i is the distance between x and y. The subconstitutent algebra T = T(x) of Q_D with respect to x is generated by A and A* . We show that A 2A* − 2AA*A + A*A 2 = 4A* A*2A − 2A*AA* + …


Maximality And Applications Of Subword-Closed Languages, Rhys Davis Jones Jan 2020

Maximality And Applications Of Subword-Closed Languages, Rhys Davis Jones

UNF Graduate Theses and Dissertations

Characterizing languages D that are maximal with the property that D* ⊆ S is an important problem in formal language theory with applications to coding theory and DNA codewords. Given a finite set of words of a fixed length S, the constraint, we consider its subword closure, S, the set of words whose subwords of that fixed length are all in the constraint. We investigate these maximal languages and present characterizations for them. These characterizations use strongly connected components of deterministic finite automata and lead to polynomial time algorithms for generating such languages. We prove that …


Harmonic Morphisms With One-Dimensional Fibres And Milnor Fibrations, Murphy Griffin Jan 2020

Harmonic Morphisms With One-Dimensional Fibres And Milnor Fibrations, Murphy Griffin

UNF Graduate Theses and Dissertations

We study a problem at the intersection of harmonic morphisms and real analytic Milnor fibrations. Baird and Ou establish that a harmonic morphism from G: \mathbb{R}^m \setminus V_G \rightarrow \mathbb{R}^n\setminus \{0\} defined by homogeneous polynomials of order p retracts to a harmonic morphism \psi|: S^{m-1} \setminus K_\epsilon \rightarrow S^{n-1} that induces a Milnor fibration over the sphere. In seeking to relax the homogeneity assumption on the map G, we determine that the only harmonic morphism $\varphi: \mathbb{R}^m \setminus V_G \rightarrow S^{m-1}\K_\epsilon$ that preserves \arg G is radial projection. Due to this limitation, we confirm Baird and Ou's result, yet establish …