Physical Sciences and Mathematics Commons^™

Zeros Of Cubic Eisenstein Series, Sahak D. Sandragorsian

Theses and Dissertations - UTB/UTPA

This thesis provides a detailed exposition and extension of the work of F. K. C. Rankin and Swinnerton-Dyer on the location of the zeros of Eisenstein series for SL(2,Z). Exact values of the zeros in special cases will be given in terms of modular functions. Analogous new results on zeros of cubic Eisenstein series will be presented.

Riparian Vegetation, Colorado River, And Climate: Five Decades Of Spatiotemporal Dynamics In The Grand Canyon With River Regulation, Joel B. Sankey, Barbara Ralston, Paul E. Grams, John C. Schmidt, Laura E. Cagney

Watershed Sciences Faculty Publications

Documentation of the interacting effects of river regulation and climate on riparian vegetation has typically been limited to small segments of rivers or focused on individual plant species. We examine spatiotemporal variability in riparian vegetation for the Colorado River in Grand Canyon relative to river regulation and climate, over the five decades since completion of the upstream Glen Canyon Dam in 1963. Long-term changes along this highly modified, large segment of the river provide insights for management of similar riparian ecosystems around the world. We analyze vegetation extent based on maps and imagery from eight dates between 1965 and 2009, …

Systems Of Parameters And The Cohen-Macaulay Property, Katharine Shultis

Department of Mathematics: Dissertations, Theses, and Student Research

Let R be a commutative, Noetherian, local ring and M a finitely generated R-module. Consider the module of homomorphisms Hom_R(R/a,M/bM) where b [subset of] a are parameter ideals of M. When M = R and R is Cohen-Macaulay, Rees showed that this module of homomorphisms is isomorphic to R/a, and in particular, a free module over R/a of rank one. In this work, we study the structure of such modules of homomorphisms for a not necessarily Cohen-Macaulay R-module M.

New Product Development Flexibility In A Competitive Environment, Janne Kettunen, Yael Gruksha-Cockayne, Zeger Degraeve, Bert De Reyck

Research Collection Lee Kong Chian School Of Business

Managerial flexibility can have a significant impact on the value of new product development projects. We investigate how the market environment in which a firm operates influences the value and use of development flexibility. We characterize the market environment according to two dimensions, namely (i) its intensity, and (ii) its degree of innovation. We show that these two market characteristics can have a different effect on the value of flexibility. In particular, we show that more intense or innovative environments may increase or decrease the value of flexibility. For instance, we demonstrate that the option to defer a product launch …

Inkball Models For Character Localization And Out-Of-Vocabulary Word Spotting, Nicholas Howe

Computer Science: Faculty Publications

Inkball models have previously been used for keyword spotting under the whole word query-by-image paradigm. This paper applies inkball methods to string-based queries for the first time, using synthetic models composed from individual characters. A hybrid system using both query-by-string for unknown words and query-by-example for known words outperforms either approach by itself on the George Washington and Parzival test sets. In addition, inkball character models offer an explanatory tool for understanding handwritten markings. In combination with a transcript they can help to to attribute each ink pixel of a word image to specific letters, resulting in highquality character segmentations.

Lang’S Universal Molecule Algorithm, John C. Bowers, Ileana Streinu

Computer Science: Faculty Publications

Robert Lang’s Universal Molecule algorithm, a landmark in modern computational origami, is the main component of his widely used Tree Maker program for origami design. It computes a crease pattern of a convex polygonal region, starting with a compatible metric tree. Although it has been informally described in several publications, neither the full power nor the inherent limitations of the method are well understood. In this paper we introduce a rigorous mathematical formalism to relate the input metric tree, the output crease pattern and the folded uniaxial origami base produced by the Universal Molecule algorithm. We characterize the family of …

Improving Attenuation Correction In Hybrid Positron Emission Tomography, Hua Asher Ai

Dissertations & Theses (Open Access)

Hybrid positron emission tomography imaging techniques such as PET/CT and PET/MR have undergone significant developments over the last two decades and have played increasingly more important roles both in research and in the clinic. A unique advantage PET has over other clinical imaging modalities is its capability of accurate quantification. However, as the most critical component of PET quantification, attenuation correction in hybrid PET systems is challenged in several different aspects, including the spatial- temporal mismatch between the PET emission images and the associated attenuation images provided by the complementary modality, and the difficulty in bone identification in the MR-based …

Mathematical Studies Of The Glucose-Insulin Regulatory System Models., Minghu Wang

Electronic Theses and Dissertations

Three dynamic models are proposed to study the mechanism of glucose-insulin regulatory system and the possible causes of diabetes mellitus. The progression of diabetes comes along with the apoptosis of pancreatic beta-cells. A dynamical system model is formulated based on physiology and studied by geometric singular perturbation theory. The analytical studies reveal rich analytical features, such as persistence of solutions, Hopf bifurcation and backward bifurcation, while numerical studies successfully fit available longitudinal T2DM data of Pima Indian tribe. These studies together not only validate our model, but also point out key intrinsic factors leading to the development of T2DM. We …

The Pc-Tree Algorithm, Kuratowski Subdivisions, And The Torus., Charles J. Suer

Electronic Theses and Dissertations

The PC-Tree algorithm of Shih and Hsu (1999) is a practical linear-time planarity algorithm that provides a plane embedding of the given graph if it is planar and a Kuratowski subdivision otherwise. Remarkably, there is no known linear-time algorithm for embedding graphs on the torus. We extend the PC-Tree algorithm to a practical, linear-time toroidality test for K3;3-free graphs called the PCK-Tree algorithm. We also prove that it is NP-complete to decide whether the edges of a graph can be covered with two Kuratowski subdivisions. This greatly reduces the possibility of a polynomial-time toroidality testing algorithm based solely on edge-coverings …

Strong Quota Pair Systems And May's Theorem On Median Semilattices., Lucas Hoots

Electronic Theses and Dissertations

Kenneth May [16], in 1952, characterized simple majority rule in terms of three conditions: anonymity, neutrality, and positive responsiveness. In this thesis, we remove the condition of neutrality and obtain a characterization of the class of voting rules that satisfy anonymity and positive responsiveness. The key concept in this characterization is the notion of a strong quota pair system. The situation with two alternatives studied by May can be thought of as a very simple example of a finite median semilattice. The main result of this thesis is an extension of May’s theorem to the domain of all finite median …

Order Automorphisms On The Lattice Of Residuated Maps Of Some Special Nondistributive Lattices., Erika D. Foreman

Electronic Theses and Dissertations

The residuated maps from a lattice L to itself form their own lattice, which we denote Res(L). In this dissertation, we explore the order automorphisms on the lattice Res(L) where L is a finite nondistributive lattice. It is known that left and right composition of f ∈ Res(L) with automorphisms of L yields an order automorphism of Res(L). It begs the question, then, if all order automorphisms of Res(L) can be classified as such.

Dynamic Pricing For Competing Sellers, Liu Zhu

All Theses

To optimize profit, pricing is of great importance for each company, especially when competitors exist. The optimal pricing strategy we are interested in is to achieve Nash equilibrium (NE) to prevent malignant competition. In this work, we study dynamic pricing for a duopoly with two competing sellers, each of which sells one product, using a simple linear model which incorporates the competition effect. Motivated from the modified pricing policy constructed in Liu and Cooper [12], we propose a policy, referred to as randomized certainty equivalent pricing (RCEP) policy, under which each seller applies certainty equivalent pricing (CEP) policy for most …

Big Data, Bigger Dilemmas: A Critical Review, Hamid Ekbia, Michael Mattioli, Inna Koupe, G. Arave, Ali Ghazinejad, Timothy Bowman, Venkatq R. Suri, Tsou Andrew, Scott Weingart, Cassidy R. Sugimoto

Articles by Maurer Faculty

The recent interest in Big Data has generated a broad range of new academic, corporate, and policy practices along with an evolving debate among its proponents, detractors, and skeptics. While the practices draw on a common set of tools, techniques, and technologies, most contributions to the debate come either from a particular disciplinary perspective or with a focus on a domain-specific issue. A close examination of these contributions reveals a set of common problematics that arise in various guises and in different places. It also demonstrates the need for a critical synthesis of the conceptual and practical dilemmas surrounding Big …

Human Impacts On Fire In De Soto National Forest, Mississippi, U.S.A., Charles Raymond White

Master's Theses

Fire is a common occurrence in the longleaf pine (Pinus palustris) forests of the Southeast United States. Prescribed fire is used to manage these threatened ecosystems, but information regarding historical fire activity is unknown. My goals were to determine the historical fire regimes in De Soto National Forest (DSNF), southern Mississippi, and determine the influence of climate and land use history on fire activity at two study sites: Fern Gulley Ridge (FGR) and Death Scar Valley (DSV). The composite mean fire interval during the prescribed burning period (1980–2013) was 3.4 years. During settlements periods, fire intervals at FGR …

On The Topology Of The Permutation Pattern Poset, Peter R. W. Mcnamara, Einar Steingrímsson

Faculty Journal Articles

The set of all permutations, ordered by pattern containment, forms a poset. This paper presents the first explicit major results on the topology of intervals in this poset. We show that almost all (open) intervals in this poset have a disconnected subinterval and are thus not shellable. Nevertheless, there seem to be large classes of intervals that are shellable and thus have the homotopy type of a wedge of spheres. We prove this to be the case for all intervals of layered permutations that have no disconnected subintervals of rank 3 or more. We also characterize in a simple way …

High-Precision U-Pb Ca-Tims Calibration Of Middle Permian To Lower Triassic Sequences, Mass Extinction And Extreme Climate-Change In Eastern Australian Gondwana, I. Metcalfe, J. Crowley, R. S. Nicoll, M. Schmitz

Geosciences Faculty Publications and Presentations

Twenty-eight new high-precision Chemical Abrasion Isotope Dilution Thermal Ionisation Mass Spectrometry U-Pb zircon dates for tuffs in the Sydney and Bowen Basins are reported. Based on these new dates, the Guadalupian-Lopingian/Capitanian-Wuchiapingian boundary is tentatively placed at the level of the Thirroul Sandstone in the lower part of the Illawarra Coal Measures in the Sydney Basin. The Wuchiapingian-Changhsingian boundary is at or close to the Kembla Sandstone horizon in the Illawarra Coal Measures, southern Sydney Basin, in the middle part of the Newcastle Coal Measures in the northern Sydney Basin, and in the middle of the Black Alley Shale in the …

Advances In High-Throughput Analysis: Automated Radiochemical Separations And Nanopillar Based Separations And Field Enhanced Spectroscopy, Jennifer Jeanne Charlton

Doctoral Dissertations

Often the need to analyze a large number of samples coincide with critical time consternates. At such times, the implementation of high-throughput technologies is paramount. In this work we explore some viable pathways for high-throughput analysis and develop advancements in novel forms of detection of materials that are vital in the environmental, biological as well as national security arenas. Through the use of new protocols with high sensitivity and specificity as well as simplified chemical processing and sample preparation we aim to allow for improved throughput, fieldable detection, and rapid data acquisition of extensive sample sets. The methods developed in …

Crystal Growth And Physical Property Characterization Of Complex Perovskite Oxides, Ling Li

Doctoral Dissertations

Bulk EuTiO₃ [europium titanate], a quantum paraelectric antiferromagnet, is shown to exhibit multiferroic behavior in strained thin film form, which highlights the spin-phonon coupling in this system. We have investigated the structural, elastic, magnetic, thermal and transport properties of single crystals of EuTiO₃ as well as doped system EuTi_1-xB_xO₃ (B = Zr, Nb) [Zr and Nb doped europium titanate] utilizing various experimental techniques and theoretical calculations.

The cubic to tetragonal structural transition in pure EuTiO₃ is characterized by a pronounced step-like softening of the elastic moduli near 288 K [kelvin], which resembles …

Turfgrasses Of Kentucky, Gregg Munshaw

Agriculture and Natural Resources Publications

Roughly 7,500 grass species are grown around the world, but only 14 species are adapted as turfgrasses that have been used extensively. Kentucky is situated in the transitional climatic zone of the United States, the middle point between the cool north and the warm south, with warm summers and cool winters. Because of its unusual climate, no single grass is suitable for all situations and locations.

Metal-Free Tandem Beckmann–Electrophilic Aromatic Substitution Cascade Affording Diaryl Imines, Ketones, Amines, And Quinazolines, Samuel Sarsah, Marlon R. Lutz Jr., Kailyn Chichi Bobb, Daniel Becker

Chemistry: Faculty Publications and Other Works

A cascade reaction sequence involving a Beckmann rearrangement on benzophenone oxime followed by an electrophilic aromatic substitution (EAS) on the intermediate nitrilium ion affords N-phenyl diaryl imines that may then be hydrolyzed to ketones, or reduced to the corresponding amines. Reaction with benzonitrile afforded 2,4-diphenylquinazoline through a Beckmann–Ritter–EAS cascade.

The Lunar Exosphere: Spatial And Temporal Variations Of Sodium And Potassium Emissions From November 2013 To May 2014, Dona Chathuni P. Kuruppuaratchi

Doctoral Dissertations and Master's Theses

I apply high resolution spectroscopy to investigate the lunar exosphere by measuring sodium and potassium spectral line profiles to determine spatial and temporal variations in exospheric effective temperatures and velocities. Observations were made from the National Solar Observatory (MMP) at Kitt Peak, Arizona from November 2013 to May 2014, with the exception of March 2014. Data collection was centered of full moon and spanned several nights with lunar phase angle coverage ranging from 65.6° (waxing) to 78.7° (waning). Observations were concurrent with the NASA LADEE mission science and instrument testing phases. We used a dial etalon Fabry-Perot spectrometer with a …

Comparison Of Two Parameter Estimation Techniques For Stochastic Models, Thomas C. Robacker

Electronic Theses and Dissertations

Parameter estimation techniques have been successfully and extensively applied to deterministic models based on ordinary differential equations but are in early development for stochastic models. In this thesis, we first investigate using parameter estimation techniques for a deterministic model to approximate parameters in a corresponding stochastic model. The basis behind this approach lies in the Kurtz limit theorem which implies that for large populations, the realizations of the stochastic model converge to the deterministic model. We show for two example models that this approach often fails to estimate parameters well when the population size is small. We then develop a …

The Integration Of Kinesthetic Learning Through The Math & Movement Program: Pilot Study 2015, Benjamin Ferder

Master's Theses

Purpose: The primary purpose of this pilot study was to verify that the use of kinesthetic learning (Math & Movement Program) in the classroom increases retention of multiplication facts at a greater rate than traditional drill and practice. The Math & Movement Program uses a kinesthetic learning-based approach for practicing, learning, and memorizing mathematics through the incorporation of bodily movement(s). Participants: The directors of the research project for the participating school district selected the sample of convenience. The population size of this study included 213 third and fourth grade students during the second half of the 2011-2012 school years. Data …

Measurement Of Hysteretic Shale Capillary Pressure – Saturation Relationships Using A Water Activity Meter, Brendan Michael Donnelly

Masters Theses

Capillary pressure is the pressure difference across the interface of two immiscible fluids within a porous medium due to the interfacial tension between fluids and is related to both the properties of the fluids and the porous medium. Capillary pressure within a porous medium will change depending upon its degree of saturation. Understanding the relationship between capillary pressure and saturation for a rock allows for the modeling of multi-phase flow. Many traditional methods of measuring capillary pressure are unsuitable for the characterization of shale due to their inability to measure the high capillary pressures found within the small pores. Furthermore, …

Nanocontact Disorder In Nanoelectronics For Modulation Of Light And Gas Sensitivities, Yen-Fu Lin, Chia-Hung Chang, Tsu-Chang Hung, Wen-Bin Jian, Kazuhito Tsukagoshi, Yue-Han Wu, Li Chang, Zhaoping Liu, Jiye Fang

Chemistry Faculty Scholarship

To fabricate reliable nanoelectronics, whether by top-down or bottom-up processes, it is necessary to study the electrical properties of nanocontacts. The effect of nanocontact disorder on device properties has been discussed but not quantitatively studied. Here, by carefully analyzing the temperature dependence of device electrical characteristics and by inspecting them with a microscope, we investigated the Schottky contact and Mott's variable-range-hopping resistances connected in parallel in the nanocontact. To interpret these parallel resistances, we proposed a model of Ti/TiOx in the interface between the metal electrodes and nanowires. The hopping resistance as well as the nanocontact disorder dominated the total …

X-Ray Spectroscopy Of Ultra-Thin Oxide/Oxide Heteroepitaxial Films: A Case Study Of Single-Nanometer Vo2/Tio2, Nicholas F. Quackenbush, Hanjong Paik, Joseph C. Woicik, Dario A. Arena, Darrell G. Schlom, Louis Piper

Physics, Applied Physics and Astronomy Faculty Scholarship

Epitaxial ultra-thin oxide films can support large percent level strains well beyond their bulk counterparts, thereby enabling strain-engineering in oxides that can tailor various phenomena. At these reduced dimensions (typically < 10 nm), contributions from the substrate can dwarf the signal from the epilayer, making it difficult to distinguish the properties of the epilayer from the bulk. This is especially true for oxide on oxide systems. Here, we have employed a combination of hard X-ray photoelectron spectroscopy (HAXPES) and angular soft X-ray absorption spectroscopy (XAS) to study epitaxial VO2/TiO2 (100) films ranging from 7.5 to 1 nm. We observe a low-temperature (300 K) insulating phase with evidence of vanadium-vanadium (V-V) dimers and a high-temperature (400 K) metallic phase absent of V-V dimers irrespective of film thickness. Our results confirm that the metal insulator transition can exist at atomic dimensions and that biaxial strain can still be used to control the temperature of its transition when the interfaces are atomically sharp. More generally, our case study highlights the benefits of using non-destructive XAS and HAXPES to extract out information regarding the interfacial quality of the epilayers and spectroscopic signatures associated with exotic phenomena at these dimensions.

Long-Term Study Of Crowdfunding Platform: Predicting Project Success And Fundraising Amount, Jinwook Chung

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Crowdfunding that is the combination word of crowdsourcing and funding makes people can start a business easily. Legislating JOBS act in US played a major role in removing restricted barriers of crowdfunding on public offerings of fence and private funds for small business. The growth speed of crowdfunding takes some beating. Through Kickstarter that is a popular crowdfunding platform and being considered the typical case of crowdfunding, 480 million dollars and more than half a billion dollars were invested in about 19 thousand and 22 projects for 2013 and 2014 respectively. But in spite of the rapid growth, the successful …

Detecting Experts On Quora: By Their Activity, Quality Of Answers, Linguistic Characteristics And Temporal Behaviors, Sumanth Kumar Reddy Nagarur Patil

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Question and answering sites are useful in sharing the knowledge by answering questions. It is a medium of sharing knowledge. Quora is the fastest emerging effective Q&A site, which is the best source of knowledge. Here you can ask a question, and get help in getting answers from people with firsthand experience, and blog about what you know. In this paper, we are investigating and identifying potential experts who are providing the best solutions to the questioner needs. We have considered several techniques in identifying user as an expert or non-expert. We have targeted the most followed topics in Quora …

The Colorado Plateau As A Virtual Laboratory For Mobile Games For Geoscience Education And Relations Between Rock Strength And River Metrics, Natalie Bursztyn

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This dissertation encompasses two studies: one developing virtual field trips for mobile devices for an innovative approach to lower-division geoscience education, and the other examining the role of rock strength in river erosion and landscape evolution.

The education study involves the development of three virtual field trip modules (Geologic Time, Geologic Structures, and Hydrologic Processes, all free on iTunes and Google Play) that lead students down a virtual Colorado River through Grand Canyon by physically moving around their campus quad, football field or other location, using their GPS-equipped smart phone or tablet. As students reach each location in the scaled …

Peroxy Radical - Water Complexes: Their Role In The Atmosphere, Sambhav Rajendra Kumbhani

Theses and Dissertations

The importance of radical-water complexes in the atmosphere is explored in this dissertation. Radicals, although present in small concentrations in the atmosphere, play a significant role in creating and removing atmospheric pollution. As the atmosphere warms and consequently gets wetter, it is essential to understand the effects of water vapor on radical chemistry. This dissertation reports studies on the effects of water vapor on the kinetics of the self-reaction of β-hydroxyethyl peroxy radical (β-HEP), a prominent organic peroxy radical in the atmosphere. Both experimental and computational studies have been performed to examine the effects of water vapor on the kinetics …