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2011

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Articles 61 - 90 of 883

Full-Text Articles in Mathematics

A High-Resolution Finite-Difference Method For Simulating Two-Fluid, Viscoelastic Gel Dynamics, Grady Wright, Robert D. Guy, Jian Du, Aaron L. Fogelson Oct 2011

A High-Resolution Finite-Difference Method For Simulating Two-Fluid, Viscoelastic Gel Dynamics, Grady Wright, Robert D. Guy, Jian Du, Aaron L. Fogelson

Mathematics Faculty Publications and Presentations

An important class of gels are those composed of a polymer network and fluid solvent. The mechanical and rheological properties of these two-fluid gels can change dramatically in response to temperature, stress, and chemical stimulus. Because of their adaptivity, these gels are important in many biological systems, e.g. gels make up the cytoplasm of cells and the mucus in the respiratory and digestive systems, and they are involved in the formation of blood clots. In this study we consider a mathematical model for gels that treats the network phase as a viscoelastic fluid with spatially and temporally varying material parameters …

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Alternative Proofs On The Indices Of Cacti And Unicyclic Graphs With N Vertices, Sudipta Mallik Oct 2011

Alternative Proofs On The Indices Of Cacti And Unicyclic Graphs With N Vertices, Sudipta Mallik

Mathematics Faculty Research

Let Hn be the cactus obtained from the star K1,n—1 by adding └ n—1/2┘ independent edges between pairs of pendant vertices. Let K1,+n—1 be the unicyclic graph obtained from the star by appending one edge. In this paper we give alternative proofs of the following results: Among all cacti with n vertices, Hn is the unique cactus whose spectral radius is maximal, and among all unicyclic graphs with n vertices, K1,+n—1 is the unique unicyclic graph whose spectral radius is maximal. We also prove …

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Infinitary Equivalence Of Zp- Modules With Nice Decomposition Bases, Rüdiger Göbel, Katrin Leistner, Peter Loth, Lutz Strüngmann Oct 2011

Infinitary Equivalence Of Zp- Modules With Nice Decomposition Bases, Rüdiger Göbel, Katrin Leistner, Peter Loth, Lutz Strüngmann

Mathematics Faculty Publications

Warfield modules are direct summands of simply presented Zp - modules, or, alternatively, are Zp - modules possessing a nice decomposition basis with simply presented cokernel. They have been classified up to isomorphism by theor Ilm-Kaplansky and Warfield invariants. Taking a model theoretic point of view and using infinitary languages we give here a complete theoretic characterization of a large class of Zp - modules having a nice decomposition basis. As a corollary, we obtain the classical classification of countable Warfield modules. This generalizes results by Barwise and Eklof.

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An Experimental Nexos Laboratory Using Virtual Xinu, Paul Ruth, Dennis Brylow Oct 2011

An Experimental Nexos Laboratory Using Virtual Xinu, Paul Ruth, Dennis Brylow

Mathematics, Statistics and Computer Science Faculty Research and Publications

The Nexos Project is a joint effort between Marquette University, the University of Buffalo, and the University of Mississippi to build curriculum materials and a supporting experimental laboratory for hands-on projects in computer systems courses. The approach focuses on inexpensive, flexible, commodity embedded hardware, freely available development and debugging tools, and a fresh implementation of a classic operating system, Embedded Xinu, that is ideal for student exploration. This paper describes an extension to the Nexos laboratory that includes a new target platform composed of Qemu virtual machines. Virtual Xinu addresses two challenges that limit the effectiveness of Nexos. First, potential …

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Completeness Of Interacting Particles, Pavel Abramski Oct 2011

Completeness Of Interacting Particles, Pavel Abramski

Doctoral

This thesis concerns the completeness of scattering states of n _-interacting particles in one dimension. Only the repulsive case is treated, where thereare no bound states and the spectrum is entirely absolutely continuous, so the scattering Hilbert space is the whole of L2(Rn). The thesis consists of 4 chapters: The first chapter describes the model, the scattering states as given by the Bethe Ansatz, and the main completeness problem. The second chapter contains the proof of the completeness relation in the case of two particles: n = 2. This case had in fact already been treated by B. Smit (1997), …

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Squaring, Cubing, And Cube Rooting, Arthur T. Benjamin Sep 2011

Squaring, Cubing, And Cube Rooting, Arthur T. Benjamin

All HMC Faculty Publications and Research

We present mentally efficient algorithms for mentally squaring and cubing 2-digit and 3-digit numbers and for finding cube roots of numbers with 2-digit or 3-digit answers.

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Spectral Properties Of Large Dimensional Random Circulant Type Matrices., Koushik Saha Dr. Sep 2011

Spectral Properties Of Large Dimensional Random Circulant Type Matrices., Koushik Saha Dr.

Doctoral Theses

Consider a sequence of matrices whose dimension increases to infinity. Suppose the entries of this sequence of matrices are random. These matrices with increasing dimension are called large dimensional random matrices (LDRM).Practices of random matrices, more precisely the properties of their eigenvalues, has emerged first from data analysis (beginning with Wishart (1928) [132]) and then from statistical models for heavy nuclei atoms (beginning with Wigner (1955) [130]). To insist on its physical applications, a mathematical theory of the spectrum of the random matrices began to emerge with the work of E. P. Wigner, F. J. Dyson, M. L. Mehta, C. …

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Simplicial Bredon-Illman Cohomology With Local Coefficients., Debashis Sen Dr. Sep 2011

Simplicial Bredon-Illman Cohomology With Local Coefficients., Debashis Sen Dr.

Doctoral Theses

The notion of cohomology with local coefficients for topological spaces arose with the work of Steenrod [Ste43, Ste99], in connection with the problem of extending sections of a fibration. This cohomology is built on the notion of fundamental groupoid of the space and can be described by the invariant cochain subcomplex of the cochain complex of the universal cover under the action of the fundamental group of the space. This later description is due to Eilenberg [Eil47]. Cohomology with local coefficients finds applications in many other situations.We focus on one such application of this cohomology which is due to S. …

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Lessons Learned As A Novice Researcher: A Pilot Study In Mathematics Education, Nicole L. Fonger Sep 2011

Lessons Learned As A Novice Researcher: A Pilot Study In Mathematics Education, Nicole L. Fonger

The Hilltop Review

The lessons we learn in life are often catalyzed by events or happenings that we experience and that subsequently change us in some way. Life as a graduate student is replete with diverse experiences that mold and shape one‘s outlook on teaching, learning, and disciplined inquiry. As a doctoral candidate, my role as a novice researcher is increasingly budding with growth and my responsibilities to design and conduct research have engendered some important lessons. Often confined to private or classroom conversations with graduate students and faculty members, the lessons I have learned as a novice researcher seem worth sharing to …

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A Branching Process For Virus Survival, J. Theodore Cox, Rinaldo B. Schinazi Sep 2011

A Branching Process For Virus Survival, J. Theodore Cox, Rinaldo B. Schinazi

Mathematics - All Scholarship

Quasispecies theory predicts that there is a critical mutation probability above which a viral population will go extinct. Above this threshold the virus loses the ability to replicate the best adapted genotype, leading to a population composed of low replicating mutants that is eventually doomed. We propose a new branching model that shows that this is not necessarily so. That is, a population composed of ever changing mutants may survive.

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Toric Symmetry Of Cp3, Dagan Karp, Dhruv Ranganathan, Paul Riggins '12, Ursula Whitcher Sep 2011

Toric Symmetry Of Cp3, Dagan Karp, Dhruv Ranganathan, Paul Riggins '12, Ursula Whitcher

All HMC Faculty Publications and Research

We exhaustively analyze the toric symmetries of CP^3 and its toric blowups. Our motivation is to study toric symmetry as a computational technique in Gromov-Witten theory and Donaldson-Thomas theory. We identify all nontrivial toric symmetries. The induced nontrivial isomorphisms lift and provide new symmetries at the level of Gromov-Witten Theory and Donaldson-Thomas Theory. The polytopes of the toric varieties in question include the permutohedron, the cyclohedron, the associahedron, and in fact all graph associahedra, among others.

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Mixed Monotone-Generalized Contractions In Partially Ordered Probabilistic Metric Spaces, Łjubomir B.Bomir Ćirić, Ravi P. Agarwal, Bessem Samet Sep 2011

Mixed Monotone-Generalized Contractions In Partially Ordered Probabilistic Metric Spaces, Łjubomir B.Bomir Ćirić, Ravi P. Agarwal, Bessem Samet

Mathematics and System Engineering Faculty Publications

In this article, a new concept of mixed monotone-generalized contraction in partially ordered probabilistic metric spaces is introduced, and some coupled coincidence and coupled fixed point theorems are proved. The theorems Presented are an extension of many existing results in the literature and include several recent developments. © 2011 Ćirićć et al; licensee Springer.

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On The K-Theory And Homotopy Theory Of The Klein Bottle Group, Jens Harlander, Andrew Misseldine Sep 2011

On The K-Theory And Homotopy Theory Of The Klein Bottle Group, Jens Harlander, Andrew Misseldine

Mathematics Faculty Publications and Presentations

We construct infinitely many chain homotopically distinct algebraic 2-complexes for the Klein bottle group and give various topological applications. We compare our examples to other examples in the literature and address the question of geometric realizability.

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Adjoint Functors, Projectivization, And Differentiation Algorithms For Representations Of Partially Ordered Sets, Mark Kleiner, Markus Reitenbach Sep 2011

Adjoint Functors, Projectivization, And Differentiation Algorithms For Representations Of Partially Ordered Sets, Mark Kleiner, Markus Reitenbach

Mathematics - All Scholarship

Adjoint functors and projectivization in representation theory of partially ordered sets are used to generalize the algorithms of differentiation by a maximal and by a minimal point. Conceptual explanations are given for the combinatorial construction of the derived set and for the differentiation functor.

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Integral Inequalities On Time Scales Via The Theory Of Isotonic Linear Functionals, Matloob Anwar, Rabia Bibi, Martin Bohner, Josip Pečarić Sep 2011

Integral Inequalities On Time Scales Via The Theory Of Isotonic Linear Functionals, Matloob Anwar, Rabia Bibi, Martin Bohner, Josip Pečarić

Mathematics and Statistics Faculty Research & Creative Works

We apply the theory of isotonic linear functionals to derive a series of known inequalities, extensions of known inequalities, and new inequalities in the theory of dynamic equations on time scales. © 2011 Matloob Anwar et al.

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A New Framework For Network Disruption, Susan E. Martonosi, Doug Altner, Michael Ernst, Elizabeth Ferme, Kira Langsjoen, Danika Lindsay, Sean S. Plott '08, Andrew S. Ronan Sep 2011

A New Framework For Network Disruption, Susan E. Martonosi, Doug Altner, Michael Ernst, Elizabeth Ferme, Kira Langsjoen, Danika Lindsay, Sean S. Plott '08, Andrew S. Ronan

All HMC Faculty Publications and Research

Traditional network disruption approaches focus on disconnecting or lengthening paths in the network. We present a new framework for network disruption that attempts to reroute flow through critical vertices via vertex deletion, under the assumption that this will render those vertices vulnerable to future attacks. We define the load on a critical vertex to be the number of paths in the network that must flow through the vertex. We present graph-theoretic and computational techniques to maximize this load, firstly by removing either a single vertex from the network, secondly by removing a subset of vertices.

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Operation Comics: Making Math Fun, Bruce Kessler Sep 2011

Operation Comics: Making Math Fun, Bruce Kessler

Mathematics Faculty Publications

This talk gives a background on the Operation Comics series, which integrates mathematics into a comic book storyline, as an example of how creativity is not exclusive to the traditional arts, like music and dance, but is a vital part of math, science, and engineering.

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Euler Equations On A Semi-Direct Product Of The Diffeomorphisms Group By Itself, Joachim Escher, Rossen Ivanov, Boris Kolev Sep 2011

Euler Equations On A Semi-Direct Product Of The Diffeomorphisms Group By Itself, Joachim Escher, Rossen Ivanov, Boris Kolev

Articles

The geodesic equations of a class of right invariant metrics on the semi-direct product of two Diff(S) groups are studied. The equations are explicitly described, they have the form of a system of coupled equations of Camassa-Holm type and possess singular (peakon) solutions. Their integrability is further investigated, however no compatible bi-Hamiltonian structures on the corresponding dual Lie algebra are found.

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Phase History Decomposition For Efficient Scatterer Classification In Sar Imagery, Dane F. Fuller Sep 2011

Phase History Decomposition For Efficient Scatterer Classification In Sar Imagery, Dane F. Fuller

Theses and Dissertations

A new theory and algorithm for scatterer classification in SAR imagery is presented. The automated classification process is operationally efficient compared to existing image segmentation methods requiring human supervision. The algorithm reconstructs coarse resolution subimages from subdomains of the SAR phase history. It analyzes local peaks in the subimages to determine locations and geometric shapes of scatterers in the scene. Scatterer locations are indicated by the presence of a stable peak in all subimages for a given subaperture, while scatterer shapes are indicated by changes in pixel intensity. A new multi-peak model is developed from physical models of electromagnetic scattering …

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Solutions To Quasi-Relativistic Multi-Configurative Hartree-Fock Equations In Quantum Chemistry, Carlos Argáez García, Michael Melgaard Sep 2011

Solutions To Quasi-Relativistic Multi-Configurative Hartree-Fock Equations In Quantum Chemistry, Carlos Argáez García, Michael Melgaard

Articles

We establish existence of infinitely many distinct solutions to the multi-configurative Hartree-Fock type equations for N-electron Coulomb systems with quasi-relativistic kinetic energy for the n th electron. Finitely many of the solutions are interpreted as excited states of the molecule. Moreover, we prove existence of a ground state. The results are valid under the hypotheses that the total charge Z of K nuclei is greater than N-1 and that Z is smaller than a critical charge. The proofs are based on a new application of the Lions-Fang-Ghoussoub critical point approach to nonminimal solutions on a complete analytic Hilbert-Riemann manifold.

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Gm-Csf Production Allows The Identification Of Immunoprevalent Antigens Recognized By Human Cd4+ T Cells Following Smallpox Vaccination, Valeria A. Judkowski, Alcinette Bunying, Feng Ge, Jon R. Appel, Kingyee Law, Atima Sharma, Claudia Raja-Gabaglia, Patricia Norori, Radleigh Santos, Marc Giulianotti, Mark K. Slifka, Daniel C. Douek, Barney S. Graham, Clemencia Pinilla Sep 2011

Gm-Csf Production Allows The Identification Of Immunoprevalent Antigens Recognized By Human Cd4+ T Cells Following Smallpox Vaccination, Valeria A. Judkowski, Alcinette Bunying, Feng Ge, Jon R. Appel, Kingyee Law, Atima Sharma, Claudia Raja-Gabaglia, Patricia Norori, Radleigh Santos, Marc Giulianotti, Mark K. Slifka, Daniel C. Douek, Barney S. Graham, Clemencia Pinilla

Mathematics Faculty Articles

The threat of bioterrorism with smallpox and the broad use of vaccinia vectors for other vaccines have led to the resurgence in the study of vaccinia immunological memory. The importance of the role of CD4+ T cells in the control of vaccinia infection is well known. However, more CD8+ than CD4+ T cell epitopes recognized by human subjects immunized with vaccinia virus have been reported. This could be, in part, due to the fact that most of the studies that have identified human CD4+ specific protein-derived fragments or peptides have used IFN-γ production to evaluate vaccinia specific T cell responses. …

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Are Symbolic Powers Highly Evolved?, Brian Harbourne, Craig Hunkeke Sep 2011

Are Symbolic Powers Highly Evolved?, Brian Harbourne, Craig Hunkeke

Department of Mathematics: Faculty Publications

Searching for structural reasons behind old results and conjectures of Chudnovksy regarding the least degree of a nonzero form in an ideal of fat points in PN, we make conjectures which explain them, and we prove the conjectures in certain cases, including the case of general points in P2. Our conjectures were also partly motivated by the Eisenbud-Mazur Conjecture on evolutions, which concerns symbolic squares of prime ideals in local rings, but in contrast we consider higher symbolic powers of homogeneous ideals in polynomial rings.

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Lipschitz Regularity For Inner-Variational Equations, Tadeusz Iwaniec, Leonid V. Kovalev, Jani Onninen Sep 2011

Lipschitz Regularity For Inner-Variational Equations, Tadeusz Iwaniec, Leonid V. Kovalev, Jani Onninen

Mathematics - All Scholarship

We obtain Lipschitz regularity results for a fairly general class of nonlinear first-order PDEs. These equations arise from the inner variation of certain energy integrals. Even in the simplest model case of the Dirichlet energy the inner-stationary solutions need not be differentiable everywhere; the Lipschitz continuity is the best possible. But the proofs, even in the Dirichlet case, turn out to relay on topological arguments. The appeal to the inner-stationary solutions in this context is motivated by the classical problems of existence and regularity of the energy-minimal deformations in the theory of harmonic mappings and certain mathematical models of nonlinear …

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Analysis And Finite Element Approximation Of A Coupled, Continuum Pipe-Flow/Darcy Model For Flow In Porous Media With Embedded Conduits, Yanzhao Cao, Max Gunzburger, Fei Hua, Xiaoming Wang Sep 2011

Analysis And Finite Element Approximation Of A Coupled, Continuum Pipe-Flow/Darcy Model For Flow In Porous Media With Embedded Conduits, Yanzhao Cao, Max Gunzburger, Fei Hua, Xiaoming Wang

Mathematics and Statistics Faculty Research & Creative Works

We consider the continuum Darcy/pipe flow model for flows in a porous matrix containing embedded conduits; such coupled flows are present in, e.g., karst aquifers. the mathematical well-posedness of the coupled problem as well as convergence rates of finite element approximation are established in the two-dimensional case. Computational results are also provided. © 2010 Wiley Periodicals, Inc.

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Several Approaches For The Derivation Of Stationary Conditions For Elliptic Mpecs With Upper-Level Control Constraints, M Hintermüller, Boris S. Mordukhovich, T Surowiec Sep 2011

Several Approaches For The Derivation Of Stationary Conditions For Elliptic Mpecs With Upper-Level Control Constraints, M Hintermüller, Boris S. Mordukhovich, T Surowiec

Mathematics Research Reports

The derivation of multiplier-based optimality conditions for elliptic mathematical programs with equilibrium constraints (MPEC) is essential for the characterization of solutions and development of numerical methods. Though much can be said for broad classes of elliptic MPECs in both polyhedric and non-polyhedric settings, the calculation becomes significantly more complicated when additional constraints are imposed on the control. In this paper we develop three derivation methods for constrained MPEC problems: via concepts from variational analysis, via penalization of the control constraints, and via penalization of the lower-level problem with the subsequent regularization of the resulting nonsmoothness. The developed methods and obtained …

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A New Undergraduate Curriculum On Mathematical Biology At University Of Dayton, Muhammad Usman, Amit Singh Sep 2011

A New Undergraduate Curriculum On Mathematical Biology At University Of Dayton, Muhammad Usman, Amit Singh

Mathematics Faculty Publications

The beginning of modern science is marked by efforts of pioneers to understand the natural world using a quantitative approach. As Galileo wrote, "the book of nature is written in the language of mathematics". The traditional undergraduate course curriculum is heavily focused on individual disciplines like biology, physics, chemistry, mathematics rather than interdisciplinary courses. This fragmented teaching of sciences in majority of universities leave biology outside the quantitative and mathematical approaches. The landscape of biomedical science has transformed dramatically with advances in high throughput experimental approaches, which led to the huge amount of data. The best possible approach to generate …

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An Axiomatic Approach To The Non-Linear Theory Of Generalized Functions And Consistency Of Laplace Transforms, Todor D. Todorov Sep 2011

An Axiomatic Approach To The Non-Linear Theory Of Generalized Functions And Consistency Of Laplace Transforms, Todor D. Todorov

Mathematics

We offer an axiomatic definition of a differential algebra of generalized functions over an algebraically closed non-Archimedean field. This algebra is of Colombeau type in the sense that it contains a copy of the space of Schwartz distributions. We study the uniqueness of the objects we define and the consistency of our axioms. Next, we identify an inconsistency in the conventional Laplace transform theory. As an application we offer a free of contradictions alternative in the framework of our algebra of generalized functions. The article is aimed at mathematicians, physicists and engineers who are interested in the non-linear theory of …

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Characterizing Convergence Conditions For The Mα-Integral, Ian June L. Garces, Abraham P. Racca Sep 2011

Characterizing Convergence Conditions For The Mα-Integral, Ian June L. Garces, Abraham P. Racca

Mathematics Faculty Publications

Park, Ryu, and Lee recently defined a Henstock-type integral, which lies entirely between the McShane and the Henstock integrals. This paper presents two characterizing convergence conditions for this integral, and derives other known convergence theorems as corollaries.

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Combinatorial Bounds On Hilbert Functions Of Fat Points In Projective Space, Susan Cooper, Brian Harbourne, Zach Teitler Sep 2011

Combinatorial Bounds On Hilbert Functions Of Fat Points In Projective Space, Susan Cooper, Brian Harbourne, Zach Teitler

Mathematics Faculty Publications and Presentations

We study Hilbert functions of certain non-reduced schemes A supported at finite sets of points in PN, in particular, fat point schemes. We give combinatorially defined upper and lower bounds for the Hilbert function of A using nothing more than the multiplicities of the points and information about which subsets of the points are linearly dependent. When N = 2, we give these bounds explicitly and we give a sufficient criterion for the upper and lower bounds to be equal. When this criterion is satisfied, we give both a simple formula for the Hilbert function and combinatorially defined …

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The Constructions Of Almost Binary Sequence Pairs And Binary Sequence Pairs With Three-Level Autocorrelation, Xiuping Peng, Chengqian Xu, Guang Li, Krishnasamy T. Arasu Sep 2011

The Constructions Of Almost Binary Sequence Pairs And Binary Sequence Pairs With Three-Level Autocorrelation, Xiuping Peng, Chengqian Xu, Guang Li, Krishnasamy T. Arasu

Mathematics and Statistics Faculty Publications

In this letter, a new class of almost binary sequence pairs with a single zero element and three autocorrelation values is presented. The new almost binary sequence pairs are based on cyclic difference sets and difference set pairs. By applying the method to the binary sequence pairs, new binary sequence pairs with three-level autocorrelation are constructed. It is shown that new sequence pairs from our constructions are balanced or almost balanced and have optimal three-level autocorrelation when the characteristic sequences or sequence pairs of difference sets or difference set pairs are balanced or almost balanced and have optimal autocorrelations.

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