Mathematics Commons^™

Analysis Of A Mathematics Outcomes Assessment Program, Susan Ann Newman-Bourne

All-Inclusive List of Electronic Theses and Dissertations

The purpose of the study was to analyze longitudinal student data collected from the mathematics component of a general education outcomes assessment program from spring semester 1999 through spring semester 2003. The study determined whether or not newly declared Business Administration and Accounting program majors' mathematics placement scores in Numerical Skills and Elementary Algebra on a standardized pre-college assessment instrument predicted their mathematics outcomes assessment examination score on an intermediate algebra course outcomes assessment examination. The study also investigated whether the students' mathematics pre-college assessment scores predicted their mathematics outcomes assessment examination score in the Business Administration and Accounting programs' …

The Effects Of The Use Of Dynamic Geometry Software On Student Achievement And Interest, Heidi B. Hansen

Mathematics Graduate Theses

This study examines the current research that exists on the effects that the use of dynamic geometry software has on student achievement and interest level in mathematics. Additional questions examined are whether using dynamic geometry software has a greater impact on high or low achievers, and what current methods of implementation are suggested by the research. A review of the relevant literature indicates that the use of dynamic geometry software does have a positive effect on student achievement, particularly achievement in areas of high-level thinking. Insufficient research has been done on the effect that the use of dynamic geometry software …

Difference Equations Versus Differential Equations, A Possible Equivalence For The Rössler System?, Christophe Letellier, Saber Elaydi, Luis A. Aguirre, Aziz Alaoui

Mathematics Faculty Research

When a set of non linear differential equations is investigated, most of the time there is no analytical solution and only numerial integration techniques can provide accurate numerical solutions. In a general way the process of numerical integration is the replacement of a set of differential equations with a continuous dependence on the time by a model for which these time variable is discrete. When only a numerical solution is researched, a fourth-order Runge-Kutta integration scheme is usually sufficient. Nevertheless, sometimes a set of differential equations may be required and, in this case, standard schemes like the forward Euler, backward …

Enhancements To Crisp Possibilistic Reconstructability Analysis, Anas Al-Rabadi, Martin Zwick

Complex Systems Faculty Publications and Presentations

Modified Reconstructibility Analysis (MRA), a novel decomposition within the framework of set-theoretic (crisp possibilistic) Reconstructibility Analysis, is presented. It is shown that in some cases while 3-variable NPN-classified Boolean functions are not decomposable using Conventional Reconstructibility Analysis (CRA), they are decomposable using Modified Reconstructibility Analysis (MRA). Also, it is shown that whenever a decomposition of 3-variable NPN-classified Boolean functions exists in both MRA and CRA, MRA yields simpler or equal complexity decompositions. A comparison of the corresponding complexities for Ashenhurst-Curtis decompositions, and Modified Reconstructibility Analysis (MRA) is also presented. While both AC and MRA decompose some but …

A Notion Of Rectifiability Modeled On Carnot Groups, Scott D. Pauls

Dartmouth Scholarship

We introduce a notion of rectifiability modeled on Carnot groups. Precisely, we say that a subset E of a Carnot group M and N is a subgroup of M, we say E is N-rectifiable if it is the Lipschitz image of a positive measure subset of N. First, we discuss the implications of N-rectifiability, where N is a Carnot group (not merely a subgroup of a Carnot group), which include N-approximability and the existence of approximate tangent cones isometric to N almost everywhere in E. Second, we prove that, under a stronger condition concerning the existence of approximate tangent cones …

A Numerical Scheme For Mullins-Sekerka Flow In Three Space Dimensions, Sarah Marie Brown

Theses and Dissertations

The Mullins-Sekerka problem, also called two-sided Hele-Shaw flow, arises in modeling a binary material with two stable concentration phases. A coarsening process occurs, and large particles grow while smaller particles eventually dissolve. Single particles become spherical. This process is described by evolving harmonic functions within the two phases with the moving interface driven by the jump in the normal derivatives of the harmonic functions at the interface. The harmonic functions are continuous across the interface, taking on values equal to the mean curvature of the interface. This dissertation reformulates the three-dimensional problem as one on the two-dimensional interface by using …

Reconstruction Of An Unknown Boundary Portion From Cauchy Data In N-Dimensions, Kurt M. Bryan, Lester Caudill

Mathematical Sciences Technical Reports (MSTR)

We consider the inverse problem of determining the shape of some inacces­ sible portion of the boundary of a region in n dimensions from Cauchy data for the heat equation on an accessible portion of the boundary. The inverse problem is quite ill-posed, and nonlinear. We develop a Newton-like algorithm for solving the problem, with a simple and efficient means for computing the required derivatives, develop methods for regularizing the process, and provide computational examples

Determining The Length Of A One-Dimensional Bar, Natalya Yarlikina, Holly Walrath

Mathematical Sciences Technical Reports (MSTR)

In this paper we examine the inverse problem of determining the length of a one-dimensional bar from thermal measurements (temperature and heat flux) at one end of the bar (the "accessible" end); the other inaccessible end of the bar is assumed to be moving. We develop two different approaches to estimating the length of the bar, and show how one approach can also be adapted to find unknown boundary conditions at the inaccessible end of the bar.

Psl(2,7)-Extensions With Certain Ramification At Two Primes, Glen E. Simpson

Theses and Dissertations

We conduct a parallel Hunter search in order to find a degree 7 number field K ramified at primes q and p with discriminant d(K)=q^6 p^2 where q=11 and 2

Large Prandtl Number Behavior Of The Boussinesq System Of Rayleigh-Bénard Convection, Xiaoming Wang

Mathematics and Statistics Faculty Research & Creative Works

We establish the validity of the infinite Prandtl number model as an approximation of the Boussinesq system at large Prandtl number on finite and infinite time interval, as well as in some statistical sense. © 2004 Elsevier Ltd. All rights reserved.

Asymptotic Solutions Of Semilinear Stochastic Wave Equations, Pao-Liu Chow

Mathematics Research Reports

Large-time asymptotic properties of solutions to a class of semilinear stochastic wave equations with damping in a bounded domain are considered. First an energy inequality and the exponential bound for a linear stochastic equation are established. Under appropriate conditions, the existence theorem for a unique global solution is given. Next the questions of bounded solutions and the exponential stability of an equilibrium solution, in mean-square and the almost sure sense, are studied. Then, under some sufficient conditions, the existence of a unique invariant measure is proved. Two examples are presented to illustrate some applications of the theorems.

Oscillation Of Symplectic Dynamic Systems, Martin Bohner, Ondřej Došlý

Mathematics and Statistics Faculty Research & Creative Works

We investigate oscillatory properties of a perturbed symplectic dynamic system on a time scale that is unbounded above. the unperturbed system is supposed to be Non oscillatory, and we give conditions on the perturbation matrix, which guarantee that the perturbed system becomes oscillatory. Examples illustrating the general results are given as well. © Australian Mathematical Society 2004.

A Liouville-Gelfand Equation For K-Hessian Operators, Jon T. Jacobsen

All HMC Faculty Publications and Research

In this paper we establish existence and multiplicity results for a class of fully nonlinear elliptic equations of k-Hessian type with exponential nonlinearity. In particular, we characterize the precise dependence of the multiplicity of solutions with respect to both the space dimension and the value of k. The choice of exponential nonlinearity is motivated by the classical Liouville-Gelfand problem from combustible gas dynamics and prescribed curvature problems.

Nice Polynomials, Jonathan Groves

Masters Theses & Specialist Projects

We consider the problem of finding, constructing, and classifying nice polynomials. After a short history of previous results, we present a general property of nice polynomials which leads to an important modification of the concept of equivalence classes of nice polynomials. We give several important results on nice symmetric or antisymmetric polynomials with an odd number of roots, which dramatically increase the speed of a computer search for examples. We present complete solutions to the symmetric three root case, the general three root case, and the symmetric four root case. We also give the relations between the roots and critical …

A High -Order Finite Difference Method For Solving Bioheat Transfer Equations In Three-Dimensional Triple -Layered Skin Structure, Haofeng Yu

Doctoral Dissertations

Investigations on instantaneous skin burns are useful for an accurate assessment of burn-evaluation and for establishing thermal protections for various purposes. Meanwhile, hyperthermia with radiation is important in the treatment of cancer, and it is essential for developers and users of hyperthermia systems to predict, and interpret correctly the biomass thermal and vascular response to heating. In this dissertation, we employ the well-known Pennes' bioheat transfer equation to predict the degree of skin burn and the temperature distribution in hyperthermia cancer treatment.

A fourth-order compact finite difference scheme is developed to solve Pennes' bioheat transfer equation in a three-dimensional single …

Model Parameters And Outbreak Control For Sars, Christopher Kribs, Gerardo Chowell, Carlos Castillo-Chavez, Paul W. Fenimore, Leon Arriola, James M. Hyman

Mathematics Faculty Publications - Archive

Control of the 2002–2003 severe acute respiratory syndrome (SARS) outbreak was based on rapid diagnosis coupled with effective patient isolation. We used uncertainty and sensitivity analysis of the basic reproductive number R0 to assess the role that model parameters play in outbreak control. The transmission rate and isolation effectiveness have the largest fractional effect on R0. We estimated the distribution of the reproductive number R0 under perfect isolation conditions. The distribution lies in the interquartile range 0.19–1.08, with a median of 0.49. Even though the median of R0 is <1, we found that 25% of our R0 distribution lies at R0 > 1, even with perfect isolation. This implies the need to simultaneously …

Evolutionary Convergence To Ideal Free Dispersal Strategies And Coexistence, Richard Gejji, Yuan Lou, Daniel Munther, Justin Peyton

Mathematics and Statistics Faculty Publications

We study a two species competition model in which the species have the same population dynamics but different dispersal strategies and show how these dispersal strategies evolve. We introduce a general dispersal strategy which can result in the ideal free distributions of both competing species at equilibrium and generalize the result of Averill et al. (2011). We further investigate the convergent stability of this ideal free dispersal strategy by varying random dispersal rates, advection rates, or both of these two parameters simultaneously. For monotone resource functions, our analysis reveals that among two similar dispersal strategies, selection generally prefers the strategy …

Contributions To Emerging Techniques In Survey Sampling., Sanghamitra Pal Dr.

Doctoral Theses

This dissertation contains seven Chapters. The contents in the respective Chapters may be briefly recounted as follows.A topic of classical interest in survey sampling is how to ensure the existence of a uniformly non-negative (UNN) unbiased estimator for the mean square error (MSE) of a homogeneous linear estimator (HLE) for a finite survey population total. Hájek (1958), Vijayan (1975), Rao and Vijayan (1977) and Rao (1979) developed a number of results which boil down to the folowing as narrated in the monograph by Chaudhuri and Stenger (1992).If there exist non-zero constants w, and the unknown values y, of the variable …

An Experimental Study Of Micron-Scale Droplet Aerosols Produced Via Ultrasonic Atomization, Thomas D. Donnelly, J. Hogan '03, A. Mugler '04, N. Schommer '04, M. Schubmehl '02, Andrew J. Bernoff, B. Forrest '02

All HMC Faculty Publications and Research

In the last 10 years, laser-driven fusion experiments performed on atomic clusters of deuterium have shown a surprisingly high neutron yield per joule of input laser energy. Results indicate that the optimal cluster size for maximizing fusion events should be in the 0.01–μm diameter range, but an appropriate source of droplets of this size does not exist. In an attempt to meet this need, we use ultrasonic atomization to generate micron-scale droplet aerosols of high average density, and we have developed and refined a reliable droplet sizing technique based on Mie scattering. Harmonic excitation of the fluid in …

How To Increase The Ability Of A Student To Learn, Srinivas R. Chakravarthy

Industrial & Manufacturing Engineering Presentations And Conference Materials

An instructor is always challenged when covering the materials in a course (according to the syllabus) and at the same time making sure that all students have the opportunity to learn and understand the materials presented in the classroom. In this paper we will present some ideas and tools that enable one to try to achieve a balance. These are based on the author’s experience and perspective in teaching deterministic and stochastic operations research courses.

A New Approach To Lie Symmetry Groups Of Minimal Surfaces, Robert D. Berry

Theses and Dissertations

The Lie symmetry groups of minimal surfaces by way of planar harmonic functions are determined. It is shown that a symmetry group acting on the minimal surfaces is isomorphic with H × H^2 — the analytic functions and the harmonic functions. A subgroup of this gives a generalization of the associated family which is examined.

Absolutely Continuous Representations And A Kaplansky Density Theorem For Free Semigroup Algebras, Kenneth R. Davidson, Jiankui Li, David R. Pitts

Department of Mathematics: Faculty Publications

We introduce notions of absolutely continuous functionals and representations on the non-commutative disk algebra An. Absolutely continuous functionals are used to help identify the type L part of the free semigroup algebra associated to a ∗-extendible represen- tation . A ∗-extendible representation of An is regular if the absolutely continuous part coincides with the type L part. All known examples are regular. Absolutely continuous func- tionals are intimately related to maps which intertwine a given ∗-extendible representation with the left regular representation. A simple application of these ideas extends reflexivity and hyper-reflexivity results. Moreover the use of absolute continuity is …

Assessment Of Surface Water Runoff And Groundwater Recharge Using Mathematical Models, Khaled Omar Mohamed Haroon

Accounting Dissertations

In and semi-arid regions, surface water resources are scarce and, in most cases, groundwater is the onlynatural resource of freshwater. Pumping of groundwater often exceeds natural recharge. Therefore,groundwater level are declining and its quality is deteriorating. Sustainable management of groundwater is thus a key Issue and requires implementation of appropriate technologies to augment ground water resources. Artificial recharge augments the natural movement of surface water into the underground form' illations using some means of construction whereby surface water from streams or lakes is made to infiltrate into the ground.

The UAE is known by its arid conditions and limited …

Multi-Scale Continuum Mechanics: From Global Bifurcations To Noise Induced High-Dimensional Chaos, Ira B. Schwartz, David S. Morgan, Lora Billings, Ying-Cheng Lai

Department of Mathematics Faculty Scholarship and Creative Works

Many mechanical systems consist of continuum mechanical structures, having either linear or nonlinear elasticity or geometry, coupled to nonlinear oscillators. In this paper, we consider the class of linear continua coupled to mechanical pendula. In such mechanical systems, there often exist several natural time scales determined by the physics of the problem. Using a time scale splitting, we analyze a prototypical structural–mechanical system consisting of a planar nonlinear pendulum coupled to a flexible rod made of linear viscoelastic material. In this system both low-dimensional and high-dimensional chaos is observed. The low-dimensional chaos appears in the limit of small coupling between …

A Gibbs Sampling Approach To Maximum A Posteriori Time Delay And Amplitude Estimations, Michele Picarelli

Dissertations

Research concerned with underwater propagation in a shallow ocean environment is a growing area of study. In particular, the development of fast and accurate computational methods to estimate environmental parameters and source location is desired. In this work, only select features of the acoustic field are investigated, namely, the time delays and amplitudes of individual paths, the signal-to-noise ratio, and the number of multi-path arrivals. The amplitudes and delays contain pertinent information about the geometry associated with the environment of interest. Estimating the time delays and amplitudes of select paths in a manner that is both accurate and time efficient, …

Mixing Enhancement By Dual Speed Rotating Stirrer, Arnaud Goullet

Dissertations

Stirring is a well-known means of fluid mixing due to the emergence of complex patterns in the flow, even at low Reynolds numbers. In this work, we consider a stirrer rotating along a circular trajectory at constant speed. The fluid flow, considered incompressible, inviscid and two dimensional (in a circular container), is modeled by a point vortex model consisting of a vortex rotating in a circular container at constant angular speed. The mixing problem is addressed by considering the Hamiltonian form of the advection equations formulated in a frame of reference moving with the vortex. The dynamics of passive fluid …

Nonlinear Long-Wave Interfacial Stability Of Two-Layer Gas-Liquid Flow, Tetyana Segin

Dissertations

The flow of two immiscible viscous fluids in a thin inclined channel is considered, in either a cocurrent or countercurrent regime. Following the air-water case, which is found in a variety of engineering systems, we allow the upper fluid to be either compressible or incompressible. The disparity of the length scales and the density and viscosity ratios of the two fluids is exploited through a lubrication approximation of the conservation of mass and the Navier-Stokes equations. As a result of this long-wave theory, a coupled nonlinear system of partial differential equations is obtained that describes the evolution of the interfacial …

On The Behavior Of The Algebraic Transfer, Robert R. Bruner, Lê M. Hà, Nguyễn H. V Hưng

Mathematics Faculty Research Publications

Let Tr_k : ��_2 (⊗ over GL_k) PH_i(B��_k) → Ext^(k,k+i)_A(��_2,��_2) be the algebraic transfer, which is defined by W. Singer as an algebraic version of the geometrical transfer tr_k : π_∗^S((B��_k)_+) → π_∗^S(S^0). It has been shown that the algebraic transfer is highly nontrivial and, more precisely, that Tr_k is an isomorphism for k = 1,2,3. However, Singer showed that Tr_5 is not an epimorphism. In this paper, we prove that Tr_4 does not detect the non zero element g_s ∈ Ext^(4,12·2^s)_A(��_2,��_2) for every s ≥ 1. As a consequence, the localized (Sq^0)^(−1)Tr_4 given by inverting the squaring operation Sq^0 …

Some Studies On Uncertainty Management In Dynamical System Using Fuzzy Techniques With Applications., Kausik Majumdar Dr.

Doctoral Theses

Unceriain information processing by fuzzy if-then rules has received a lot of attention. Here we have taken a different path to model a system. about which we do not have precise information namely. modelling the system by fuzy valued functions without resorting to fuzzy if-then rules. As a result. the phase (state) space of the system becomes a full set and the underlying fuzzy mapping becomes a fuzzy attainability vet mappine. A fuzzy phase space is a collection of special class of furry subsets (fuzsy points) of R&for some positive integral n. Let the collection of all fuzr, real numbers …

Elliptic Curves Of Large Rank And Small Conductor, Noam D. Elkies, Mark Watkins

Mathematics - All Scholarship

For r=6,7,...,11 we find an elliptic curve E/Q of rank at least r and the smallest conductor known, improving on the previous records by factors ranging from 1.0136 (for r=6) to over 100 (for r=10 and r=11). We describe our search methods, and tabulate, for each r=5,6,...,11, the five curves of lowest conductor, and (except for r=11) also the five of lowest absolute discriminant, that we found.