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Articles 1 - 30 of 31
Full-Text Articles in Physical Sciences and Mathematics
Mathematical Modeling Of Immune Responses To Hepatitis C Virus Infection, Ivan Ramirez
Mathematical Modeling Of Immune Responses To Hepatitis C Virus Infection, Ivan Ramirez
Electronic Theses and Dissertations
An existing mathematical model of ordinary differential equations was studied to better understand the interactions between hepatitis C virus (HCV) and the immune system cells in the human body. Three possible qualitative scenarios were explored: dominant CTL response, dominant antibody response, and coexistence. Additionally, a sensitivity analysis was carried out to rank model parameters for each of these scenarios. Therapy was addressed as an optimal control problem. Numerical solutions of optimal controls were computed using a forward-backward sweep scheme for each scenario. Model parameters were estimated using ordinary least squares fitting from longitudinal data (serum HCV RNA measurements) given in …
The Use Of Variable-Bagging And The Cross-Validation Selector In The Prediction Of Alzheimer’S Using The Adni Database., Michael Wayne Godbey
The Use Of Variable-Bagging And The Cross-Validation Selector In The Prediction Of Alzheimer’S Using The Adni Database., Michael Wayne Godbey
Electronic Theses and Dissertations
Dimensionality plays a huge part in the modeling process. If there are more elements in a data set than variables in each element then there are very few restrictions in selection of an algorithm. Bagging, bootstrap aggregating (Breiman, 1994), may also be used to improve a model’s prediction capability. On the other hand, if there more variables in each observation than the number of observations in the dataset, the number of usable algorithms is greatly reduced. The recently developed algorithm, support vector machines, was designed for such situations, in comparison to algorithms such as logistic regression which have instability issues …
Properties Of Small Ordered Graphs Whose Vertices Are Weighted By Their Degree, Constance M. Blalock
Properties Of Small Ordered Graphs Whose Vertices Are Weighted By Their Degree, Constance M. Blalock
Electronic Theses and Dissertations
Graphs can effectively model biomolecules, computer systems, and other applications. A weighted graph is a graph in which values or labels are assigned to the edges of the graph. However, in this thesis, we assign values to the vertices of the graph rather than the edges and we modify several standard graphical measures to incorporate these vertex weights. In particular, we designate the degree of each vertex as its weight. Previous research has not investigated weighting vertices by degree. We find the vertex weighted domination number in connected graphs, beginning with trees, and we define how weighted vertices can affect …
Survey Of Graph Embeddings Into Compact Surfaces, Sophia N. Potoczak
Survey Of Graph Embeddings Into Compact Surfaces, Sophia N. Potoczak
Electronic Theses and Dissertations
A prominent question of topological graph theory is "what type of surface can a nonplanar graph be embedded into?" This thesis has two main goals. First to provide a necessary background in topology and graph theory to understand the development of an embedding algorithm. The main purpose is developing and proving a direct constructive embedding algorithm that takes as input the graph with a particular order of edges about each vertex. The embedding algorithm will not only determine which compact surface the graph can be embedded into, but also determines the particular embedding of the graph on the surface. The …
Bipartitions Based On Degree Constraints, Pamela I. Delgado
Bipartitions Based On Degree Constraints, Pamela I. Delgado
Electronic Theses and Dissertations
For a graph G = (V,E), we consider a bipartition {V1,V2} of the vertex set V by placing constraints on the vertices as follows. For every vertex v in Vi, we place a constraint on the number of neighbors v has in Vi and a constraint on the number of neighbors it has in V3-i. Using three values, namely 0 (no neighbors are allowed), 1 (at least one neighbor is required), and X (any number of neighbors are allowed) for each of the four constraints, results in 27 distinct types of …
Acyclic And Indifference-Transitive Collective Choice Functions., Katey Bjurstrom
Acyclic And Indifference-Transitive Collective Choice Functions., Katey Bjurstrom
Electronic Theses and Dissertations
Arrow's classic theorem shows that any collective choice function satisfying independence of irrelevant alternatives (IIA) and Pareto (P), where the range is a subset of weak orders, is based on a dictator. This thesis focuses on Arrovian collective choice functions in which the range is generalized to include acyclic, indifference-transitive (ACIT) relations on the set of alternatives. We show that Arrovian ACIT collective choice functions with domains satisfying the free-quadruple property are based on a unique weakly decisive voter; however, this is not necessarily true for ACIT collective choice functions where Arrow's independence condition is weakened. For ACIT collective choice …
Functional Equations With Involution Related To Sine And Cosine Functions., Allison Perkins
Functional Equations With Involution Related To Sine And Cosine Functions., Allison Perkins
Electronic Theses and Dissertations
Let G be an abelian group, C be the _eld of complex numbers, _ 2 G be any _xed, nonzero element and _ : G ! G be an involution. In Chapter 2, we determine the general solution f; g : G ! C of the functional equation f(x + _y + _) + g(x + y + _) = 2f(x)f(y) for all x; y 2 G. Let G be an arbitrary group, z0 be any _xed, nonzero element in the center Z(G) of the group G, and _ : G ! G be an involution. The main goals of …
Permutation Groups And Puzzle Tile Configurations Of Instant Insanity Ii, Amanda N. Justus
Permutation Groups And Puzzle Tile Configurations Of Instant Insanity Ii, Amanda N. Justus
Electronic Theses and Dissertations
The manufacturer claims that there is only one solution to the puzzle Instant Insanity II. However, a recent paper shows that there are two solutions. Our goal is to find ways in which we only have one solution. We examine the permutation groups of the puzzle and use modern algebra to attempt to fix the puzzle. First, we find the permutation group for the case when there is only one empty slot at the top. We then examine the scenario when we add an extra column or an extra row to make the game a 4 × 5 puzzle or …
Physiologically-Based Pharmacokinetic Model For Ertapenem, Whitney Forbes
Physiologically-Based Pharmacokinetic Model For Ertapenem, Whitney Forbes
Electronic Theses and Dissertations
Ertapenem is a carbapenem used to treat a wide range of bacterial infections. What sets ertapenem apart from other carbapenems is its longer half-life which implies it need only be administered once daily. We developed a physiologically-based pharmacokinetic model for the distribution of ertapenem within the body. In the model, parameters such as human body weight and height, age, organ volumes, blood flow rates, and partition coefficients of particular tissues are used to examine the absorption, distribution, metabolism, and excretion of ertapenem. The total and free blood concentrations found were then compared to experimental data. We then examined the sensitivity …
Are Highly Dispersed Variables More Extreme? The Case Of Distributions With Compact Support, Benedict E. Adjogah
Are Highly Dispersed Variables More Extreme? The Case Of Distributions With Compact Support, Benedict E. Adjogah
Electronic Theses and Dissertations
We consider discrete and continuous symmetric random variables X taking values in [0; 1], and thus having expected value 1/2. The main thrust of this investigation is to study the correlation between the variance, Var(X) of X and the value of the expected maximum E(Mn) = E(X1,...,Xn) of n independent and identically distributed random variables X1,X2,...,Xn, each distributed as X. Many special cases are studied, some leading to very interesting alternating sums, and some progress is made towards a general theory.
The Number Of Zeros Of A Polynomial In A Disk As A Consequence Of Restrictions On The Coefficients, Brett A. Shields Mr.
The Number Of Zeros Of A Polynomial In A Disk As A Consequence Of Restrictions On The Coefficients, Brett A. Shields Mr.
Electronic Theses and Dissertations
In this thesis, we put restrictions on the coefficients of polynomials and give bounds concerning the number of zeros in a specific region. Our results generalize a number of previously known theorems, as well as implying many new corollaries with hypotheses concerning monotonicity of the modulus, real, as well as real and imaginary parts of the coefficients separately. We worked with Enestr\"{o}m-Kakeya type hypotheses, yet we were only concerned with the number of zeros of the polynomial. We considered putting the same type of restrictions on the coefficients of three different types of polynomials: polynomials with a monotonicity``flip" at some …
Very Cost Effective Domination In Graphs, Tony K. Rodriguez
Very Cost Effective Domination In Graphs, Tony K. Rodriguez
Electronic Theses and Dissertations
A set S of vertices in a graph G=(V,E) is a dominating set if every vertex in V\S is adjacent to at least one vertex in S, and the minimum cardinality of a dominating set of G is the domination number of G. A vertex v in a dominating set S is said to be very cost effective if it is adjacent to more vertices in V\S than to vertices in S. A dominating set S is very cost effective if every vertex in S is very cost effective. The minimum cardinality of a very cost effective dominating set of …
Tiling Properties Of Spectra Of Measures, John Haussermann
Tiling Properties Of Spectra Of Measures, John Haussermann
Electronic Theses and Dissertations
We investigate tiling properties of spectra of measures, i.e., sets Λ in R such that {e 2πiλx : λ ∈ Λ} forms an orthogonal basis in L 2 (µ), where µ is some finite Borel measure on R. Such measures include Lebesgue measure on bounded Borel subsets, finite atomic measures and some fractal Hausdorff measures. We show that various classes of such spectra of measures have translational tiling properties. This lead to some surprizing tiling properties for spectra of fractal measures, the existence of complementing sets and spectra for finite sets with the Coven-Meyerowitz property, the existence of complementing Hadamard …
Comparison Of Second Order Conformal Symplectic Schemes With Linear Stability Analysis, Dwayne Floyd
Comparison Of Second Order Conformal Symplectic Schemes With Linear Stability Analysis, Dwayne Floyd
Electronic Theses and Dissertations
Numerical methods for solving linearly damped Hamiltonian ordinary differential equations are analyzed and compared. The methods are constructed from the well-known Störmer-Verlet and implicit midpoint methods. The structure preservation properties of each method are shown analytically and numerically. Each method is shown to preserve a symplectic form up to a constant and are therefore conformal symplectic integrators, with each method shown to accurately preserve the rate of momentum dissipation. An analytical linear stability analysis is completed for each method, establishing thresholds between the value of the damping coefficient and the step-size that ensure stability. The methods are all second order …
Analytical Solutions To Nonlinear Differential Equations Arising In Physical Problems, Mathew Baxter
Analytical Solutions To Nonlinear Differential Equations Arising In Physical Problems, Mathew Baxter
Electronic Theses and Dissertations
Nonlinear partial differential equations are difficult to solve, with many of the approximate solutions in the literature being numerical in nature. In this work, we apply the Homotopy Analysis Method to give approximate analytical solutions to nonlinear ordinary and partial differential equations. The main goal is to apply different linear operators, which can be chosen, to solve nonlinear problems. In the first three chapters, we study ordinary differential equations (ODEs) with one or two linear operators. As we progress, we apply the method to partial differential equations (PDEs) and use several linear operators. The results are all purely analytical, meaning …
Tiling The Integers, Shasha Li
Tiling The Integers, Shasha Li
Electronic Theses and Dissertations
A set tiles the integers if and only if the integers can be written as a disjoint union of translates of that set. Counterexamples based on finite Abelian groups show that Fuglede conjecture is false in high dimensions. A solution for the Fuglede conjecture in Z or all the groups ZN would provide a solution for the Fuglede conjecture in R. Focusing on tiles in dimension one, we will concentrate on the analysis of tiles in the finite groups ZN. Based on the Coven- Meyerowitz conjecture, it has been proved that if any spectral set in Z satisfies the the …
Functional Data Analysis And Its Application To Cancer Data, Evgeny Martinenko
Functional Data Analysis And Its Application To Cancer Data, Evgeny Martinenko
Electronic Theses and Dissertations
The objective of the current work is to develop novel procedures for the analysis of functional data and apply them for investigation of gender disparity in survival of lung cancer patients. In particular, we use the time-dependent Cox proportional hazards model where the clinical information is incorporated via time-independent covariates, and the current age is modeled using its expansion over wavelet basis functions. We developed computer algorithms and applied them to the data set which is derived from Florida Cancer Data depository data set (all personal information which allows to identify patients was eliminated). We also studied the problem of …
Electrical Conductivity Imaging Via Boundary Value Problems For The 1-Laplacian, Johann Veras
Electrical Conductivity Imaging Via Boundary Value Problems For The 1-Laplacian, Johann Veras
Electronic Theses and Dissertations
We study an inverse problem which seeks to image the internal conductivity map of a body by one measurement of boundary and interior data. In our study the interior data is the magnitude of the current density induced by electrodes. Access to interior measurements has been made possible since the work of M. Joy et al. in early 1990s and couples two physical principles: electromagnetics and magnetic resonance. In 2007 Nachman et al. has shown that it is possible to recover the conductivity from the magnitude of one current density field inside. The method now known as Current Density Impedance …
Inversion Of The Broken Ray Transform, Roman Krylov
Inversion Of The Broken Ray Transform, Roman Krylov
Electronic Theses and Dissertations
The broken ray transform (BRT) is an integral of a function along a union of two rays with a common vertex. Consider an X-ray beam scanning an object of interest. The ray undergoes attenuation and scatters in all directions inside the object. This phenomena may happen repeatedly until the photons either exit the object or are completely absorbed. In our work we assume the single scattering approximation when the intensity of the rays scattered more than once is negligibly small. Among all paths that the scattered rays travel inside the object we pick the one that is a union of …
The Characterization Of Graphs With Small Bicycle Spectrum, Bette Catherine Putnam
The Characterization Of Graphs With Small Bicycle Spectrum, Bette Catherine Putnam
Electronic Theses and Dissertations
Matroids designs are defined to be matroids in which the hyperplanes all have the same size. The dual of a matroid design is a matroid with all circuits of the same size, called a dual matroid design. The connected bicircular dual matroid designs have been characterized previously. In addition, these results have been extended to connected bicircular matroids with circuits of two sizes in the case that the associated graph is a subdivision of a 3-connected graph. In this dissertation, we will use a graph theoretic approach to discuss the characterizations of bicircular matroids with circuits of two and three …
Rank-Based Two Sample Tests Under A General Alternative, Jamye Curry
Rank-Based Two Sample Tests Under A General Alternative, Jamye Curry
Electronic Theses and Dissertations
The problem of testing whether two samples come from the same or different population is a classical one in statistics. In this dissertation, I first study rank based formulation of univariate two-sample distribution-free tests. One form of the test statistic is the average of between-group distances of ranks. The other form of the test statistic is the difference between the average of between-group distances of ranks and the average of within-group distances of ranks. Although they are different in formulation, they are closely related to the two-sample Cramer-von Mises criterion. The first one is a linear transformation of Cramer-von Mises …
(Visible) Tilings Of Squares And Hypercubes, John Randall Burt
(Visible) Tilings Of Squares And Hypercubes, John Randall Burt
Electronic Theses and Dissertations
More than eighty years ago, Erdos considered sums of the side lengths of squares packed into a unit square.Here we consider various classes of tilings , this is, packings where there is no empty space inside the unit square. Several types of questions will be explored here. Various construction techniques are introduced, especially methods of generating tilings from tilings with fewer tiles. For some small values of n, I determine all tilings of the unit square with n tiles. I have found a best possible upper bound for a visible tiling, that is a tiling which every tile shares a …
Moments Of Products Of L-Functions, Caroline Laroche Turnage-Butterbaugh
Moments Of Products Of L-Functions, Caroline Laroche Turnage-Butterbaugh
Electronic Theses and Dissertations
We first consider questions on the distribution of the primes. Using the recent advancement towards the Prime k-tuple Conjecture by Maynard and Tao, we show how to produce infinitely many strings of consecutive primes satisfying specified congruence conditions. We answer an old question of Erdös and Turán by producing strings of consecutive primes whose successive gaps form an increasing (respectively decreasing) sequence. We also show that such strings exist whose successive gaps follow a certain divisibility pattern. Finally, for any coprime integers a and D ≥ 1, we refine a theorem of D. Shiu and find strings of consecutive primes …
On The Range Of The Attenuated Radon Transform In Strictly Convex Sets., Kamran Sadiq
On The Range Of The Attenuated Radon Transform In Strictly Convex Sets., Kamran Sadiq
Electronic Theses and Dissertations
In the present dissertation, we characterize the range of the attenuated Radon transform of zero, one, and two tensor fields, supported in strictly convex set. The approach is based on a Hilbert transform associated with A-analytic functions of A. Bukhgeim. We first present new necessary and sufficient conditions for a function to be in the range of the attenuated Radon transform of a sufficiently smooth function supported in the convex set. The approach is based on an explicit Hilbert transform associated with traces of the boundary of A-analytic functions in the sense of A. Bukhgeim. We then uses the range …
Nonlinear Dispersive Partial Differential Equations Of Physical Relevance With Applications To Vortex Dynamics, Robert Vangorder
Nonlinear Dispersive Partial Differential Equations Of Physical Relevance With Applications To Vortex Dynamics, Robert Vangorder
Electronic Theses and Dissertations
Nonlinear dispersive partial differential equations occur in a variety of areas within mathematical physics and engineering. We study several classes of such equations, including scalar complex partial differential equations, vector partial differential equations, and finally non-local integro-differential equations. For physically interesting families of these equations, we demonstrate the existence (and, when possible, stability) of specific solutions which are relevant for applications. While multiple application areas are considered, the primary application that runs through the work would be the nonlinear dynamics of vortex filaments under a variety of physical models. For instance, we are able to determine the structure and time …
Ramsey Theory Using Matroid Minors, Dixie Smith Horne
Ramsey Theory Using Matroid Minors, Dixie Smith Horne
Electronic Theses and Dissertations
This thesis considers a Ramsey Theory question for graphs and regular matroids. Specifically, how many elements N are required in a 3-connected graphic or regular matroid to force the existence of certain specified minors in that matroid? This question cannot be answered for an arbitrary collection of specified minors. However, there are results from the literature for which the number N exists for certain collections of minors. We first encode totally unimodular matrix representations of certain matroids. We use the computer program MACEK to investigate this question for certain classes of specified minors.
Epistasis In Predator-Prey Relationships, Iuliia Inozemtseva
Epistasis In Predator-Prey Relationships, Iuliia Inozemtseva
Electronic Theses and Dissertations
Epistasis is the interaction between two or more genes to control a single phenotype. We model epistasis of the prey in a two-locus two-allele problem in a basic predator- prey relationship. The resulting model allows us to examine both population sizes as well as genotypic and phenotypic frequencies. In the context of several numerical examples, we show that if epistasis results in an undesirable or desirable phenotype in the prey by making the particular genotype more or less susceptible to the predator or dangerous to the predator, elimination of undesirable phenotypes and then genotypes occurs.
A Constructive Proof Of The Borel-Weil Theorem For Classical Groups, Kostiantyn Timchenko
A Constructive Proof Of The Borel-Weil Theorem For Classical Groups, Kostiantyn Timchenko
Electronic Theses and Dissertations
The Borel-Weil theorem is usually understood as a realization theorem for representations that have already been shown to exist by other means (``Theorem of the Highest Weight''). In this thesis we turn the tables and show that, at least in the case of the classical groups $G = U(n)$, $SO(n)$ and $Sp(2n)$, the Borel-Weil construction can be used to quite explicitly prove existence of an irreducible representation having highest weight $\lambda$, for each dominant integral form $\lambda$ on the Lie algebra of a maximal torus of $G$.
Structure Vs. Properties Using Chemical Graph Theory, Tabitha N. Williford
Structure Vs. Properties Using Chemical Graph Theory, Tabitha N. Williford
Electronic Theses and Dissertations
Chemical graph theory began as a way for mathematicians to bring together the areas of the Physical Sciences and Mathematics. Through its use, mathematicians are able to model chemical systems, predict their properties as well as structure-property relationships. In this dissertation, we consider two questions involving chemical graph theory and its applications. We first look at tree-like polyphenyl systems, which form an important family of compounds in Chemistry, particularly in Material Science. The importance can be seen in LEDs, transmitters, and electronics. In recent years, many extremal results regarding such systems under specific constraints have been reported. More specifically are …
Elements Of Convergence Approach Theory, William D. Trott
Elements Of Convergence Approach Theory, William D. Trott
Electronic Theses and Dissertations
We introduce two generalizations to convergence approach spaces of classical results characterizing regularity of a convergence space in terms of continuous extensions of maps on one hand, and in terms of continuity of limits for the continuous convergence on the other. Characterizations are obtained for two alternative extensions of reg- ularity to convergence-approach spaces: regularity and strong regularity. Along the way, we give a brief overview of the theory of convergence spaces and of convergence approach spaces.