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2006

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Articles 31 - 60 of 414

Full-Text Articles in Mathematics

Change Point Estimation Of Bilevel Functions, Leming Qu, Yi-Cheng Tu Nov 2006

Change Point Estimation Of Bilevel Functions, Leming Qu, Yi-Cheng Tu

Mathematics Faculty Publications and Presentations

Reconstruction of a bilevel function such as a bar code signal in a partially blind deconvolution problem is an important task in industrial processes. Existing methods are based on either the local approach or the regularization approach with a total variation penalty. This article reformulated the problem explicitly in terms of change points of the 0-1 step function. The bilevel function is then reconstructed by solving the nonlinear least squares problem subject to linear inequality constraints, with starting values provided by the local extremas of the derivative of the convolved signal from discrete noisy data. Simulation results show a considerable …


Self-Avoiding Walks And Fibonacci Numbers, Arthur T. Benjamin Nov 2006

Self-Avoiding Walks And Fibonacci Numbers, Arthur T. Benjamin

All HMC Faculty Publications and Research

By combinatorial arguments, we prove that the number of self-avoiding walks on the strip {0, 1} × Z is 8Fn − 4 when n is odd and is 8Fn − n when n is even. Also, when backwards moves are prohibited, we derive simple expressions for the number of length n self-avoiding walks on {0, 1} × Z, Z × Z, the triangular lattice, and the cubic lattice.


Multiscale Image Registration, Dana C. Paquin, Doron Levy, Lei Xing Nov 2006

Multiscale Image Registration, Dana C. Paquin, Doron Levy, Lei Xing

Mathematics

Abstract of paper presented at the 48th Annual Meeting of the American Society for Therapeutic Radiology and Oncology.


Improving The Convergence And Computational Efficiency Of Deformable Image Registration Calculation By Incorporating Prior Knowledge, S. Kamath, Eduard Schreibmann, Doron Levy, Dana C. Paquin, Lei Xing Nov 2006

Improving The Convergence And Computational Efficiency Of Deformable Image Registration Calculation By Incorporating Prior Knowledge, S. Kamath, Eduard Schreibmann, Doron Levy, Dana C. Paquin, Lei Xing

Mathematics

Abstract of a paper presented at the 48th Annual Meeting of the American Society for Therapeutic Radiology and Oncology.


On The Cohomology Of Spatial Polygons In Euclidean Spaces, Vehbi Emrah Paksoy Nov 2006

On The Cohomology Of Spatial Polygons In Euclidean Spaces, Vehbi Emrah Paksoy

Mathematics Faculty Articles

Space of spatial polygons in Euclidean spaces has been studied extensively in [3, 1, 2]. There is a beautiful description of cohomology in [1]. In this paper we introduce another, easy to compute method to obtain the cohomology without using toric variety arguments. We also give a criterion for a polygon space to be Fano, thus, having ample anticanonical class.


Maximal Clifford Semigroups Of Matrices, Edmond W. H. Lee Nov 2006

Maximal Clifford Semigroups Of Matrices, Edmond W. H. Lee

Mathematics Faculty Articles

All maximal Clifford semigroups of matrices are identified up to isomorphism. If the ground field of the matrices is finite, then there exists a unique Clifford semigroup of maximum order.


Summing Cubes By Counting Rectangles, Arthur T. Benjamin, Jennifer J. Quinn, Calyssa Wurtz Nov 2006

Summing Cubes By Counting Rectangles, Arthur T. Benjamin, Jennifer J. Quinn, Calyssa Wurtz

All HMC Faculty Publications and Research

No abstract provided in this article.


A Note On The Engulfing Property And The R 1+Α -Regularity Of Convex Functions In Carnot Groups, Luca Capogna, Diego Maldonado Nov 2006

A Note On The Engulfing Property And The R 1+Α -Regularity Of Convex Functions In Carnot Groups, Luca Capogna, Diego Maldonado

Mathematics Sciences: Faculty Publications

We study the engulfing property for convex functions in Carnot groups. As an application we show that the horizontal gradient of functions with this property is Hölder continuous.


On T-Pure And Almost Pure Exact Sequences Of Lca Groups, Peter Loth Nov 2006

On T-Pure And Almost Pure Exact Sequences Of Lca Groups, Peter Loth

Mathematics Faculty Publications

A proper short exact sequence in the category of locally compact abelian groups is said to be t-pure if φ(A) is a topologically pure subgroup of B, that is, if for all positive integers n. We establish conditions under which t-pure exact sequences split and determine those locally compact abelian groups K ⊕ D (where K is compactly generated and D is discrete) which are t-pure injective or t-pure projective. Calling the extension (*) almost pure if for all positive integers n, we obtain a complete description of the almost pure injectives and almost pure projectives in the category of …


Security In Pervasive Computing: Current Status And Open Issues, Munirul Haque, Sheikh Iqbal Ahamed Nov 2006

Security In Pervasive Computing: Current Status And Open Issues, Munirul Haque, Sheikh Iqbal Ahamed

Mathematics, Statistics and Computer Science Faculty Research and Publications

Million of wireless device users are ever on the move, becoming more dependent on their PDAs, smart phones, and other handheld devices. With the advancement of pervasive computing, new and unique capabilities are available to aid mobile societies. The wireless nature of these devices has fostered a new era of mobility. Thousands of pervasive devices are able to arbitrarily join and leave a network, creating a nomadic environment known as a pervasive ad hoc network. However, mobile devices have vulnerabilities, and some are proving to be challenging. Security in pervasive computing is the most critical challenge. Security is needed to …


Double-Slit Interference And Temporal Topos, Goro Kato, Tsunefumi Tanaka Nov 2006

Double-Slit Interference And Temporal Topos, Goro Kato, Tsunefumi Tanaka

Mathematics

The electron double-slit interference is re-examined from the point of view of temporal topos. Temporal topos (or t-topos) is an abstract algebraic (categorical) method using the theory of sheaves. A brief introduction to t-topos is given. When the structural foundation for describing particles is based on t-topos, the particle-wave duality of electron is a natural consequence. A presheaf associated with the electron represents both particle-like and wave-like properties depending upon whether an object in the site (t-site) is specified (particle-like) or not (wave-like). It is shown that the localization of the electron at one of the slits is equivalent to …


Recent Developments In Understanding Two-Dimensional Turbulence And The Nastrom-Gage Spectrum, Eleftherios Gkioulekas, Ka Kit Tung Nov 2006

Recent Developments In Understanding Two-Dimensional Turbulence And The Nastrom-Gage Spectrum, Eleftherios Gkioulekas, Ka Kit Tung

School of Mathematical & Statistical Sciences Faculty Publications

Two-dimensional turbulence appears to be a more formidable problem than three-dimensional turbulence despite the numerical advantage of working with one less dimension. In the present paper we review recent numerical investigations of the phenomenology of two-dimensional turbulence as well as recent theoretical breakthroughs by various leading researchers. We also review efforts to reconcile the observed energy spectrum of the atmosphere (the spectrum) with the predictions of two-dimensional turbulence and quasigeostrophic turbulence.


Some Problems In Additive Number Theory., Gyan Prakash Dr. Oct 2006

Some Problems In Additive Number Theory., Gyan Prakash Dr.

Doctoral Theses

No abstract provided.


The Zeta Function Of A Hypergraph, Christopher K. Storm Oct 2006

The Zeta Function Of A Hypergraph, Christopher K. Storm

Dartmouth Scholarship

We generalize the Ihara-Selberg zeta function to hypergraphs in a natural way. Hashimoto's factorization results for biregular bipartite graphs apply, leading to exact factorizations. For $(d,r)$-regular hypergraphs, we show that a modified Riemann hypothesis is true if and only if the hypergraph is Ramanujan in the sense of Winnie Li and Patrick Solé. Finally, we give an example to show how the generalized zeta function can be applied to graphs to distinguish non-isomorphic graphs with the same Ihara-Selberg zeta function.


A Classification Of Certain Maximal Subgroups Of Symmetric Groups, Benjamin Newton, Bret Benesh Oct 2006

A Classification Of Certain Maximal Subgroups Of Symmetric Groups, Benjamin Newton, Bret Benesh

Mathematics Faculty Publications

Problem 12.82 of the Kourovka Notebook asks for all ordered pairs (n,m) such that the symmetric group Sn embeds in Sm as a maximal subgroup. One family of such pairs is obtained when m=n+1. Kalužnin and Klin [L.A. Kalužnin, M.H. Klin, Certain maximal subgroups of symmetric and alternating groups, Math. Sb. 87 (1972) 91–121] and Halberstadt [E. Halberstadt, On certain maximal subgroups of symmetric or alternating groups, Math. Z. 151 (1976) 117–125] provided an additional infinite family. This paper answers the Kourovka question by producing a third infinite family of ordered …


Multiobjective Optimization Problems With Equilibrium Constraints, Boris S. Mordukhovich Oct 2006

Multiobjective Optimization Problems With Equilibrium Constraints, Boris S. Mordukhovich

Mathematics Research Reports

The paper is devoted to new applications of advanced tools of modern variational analysis and generalized differentiation to the study of broad classes of multiobjective optimization problems subject to equilibrium constraints in both finite-dimensional and infinite-dimensional settings. Performance criteria in multiobjectivejvector optimization are defined by general preference relationships satisfying natural requirements, while equilibrium constraints are described by parameterized generalized equations/variational conditions in the sense of Robinson. Such problems are intrinsically nonsmooth and are handled in this paper via appropriate normal/coderivativejsubdifferential constructions that exhibit full calculi. Most of the results obtained are new even in finite dimensions, while the case of …


Solution Methods For The P-Median Problem: An Annotated Bibliography, Josh Reese Oct 2006

Solution Methods For The P-Median Problem: An Annotated Bibliography, Josh Reese

Mathematics Faculty Research

The p-median problem is a graph theory problem that was originally designed for, and has been extensively applied to, facility location. In this bibliography, we summarize the literature on solution methods for the uncapacitated and capacitated p-median problem on a graph or network.


2006 (Fall), University Of Dayton. Department Of Mathematics Oct 2006

2006 (Fall), University Of Dayton. Department Of Mathematics

Colloquia

Abstracts of the talks givn at the 2006 Fall Colloquium.


Advising A Precollege Curriculum Project, Stephen B. Maurer , '67, W. Mccallum Oct 2006

Advising A Precollege Curriculum Project, Stephen B. Maurer , '67, W. Mccallum

Mathematics & Statistics Faculty Works

No abstract provided.


Allometric Extension For Multivariate Regression Models, Thaddeus Tarpey, Christopher T. Ivey Oct 2006

Allometric Extension For Multivariate Regression Models, Thaddeus Tarpey, Christopher T. Ivey

Mathematics and Statistics Faculty Publications

In multivariate regression, interest lies on how the response vector depends on a set of covariates. A multivariate regression model is proposed where the covariates explain variation in the response only in the direction of the first principal component axis. This model is not only parsimonious, but it provides an easy interpretation in allometric growth studies where the first principal component of the log-transformed data corresponds to constants of allometric growth. The proposed model naturally generalizes the two–group allometric extension model to the situation where groups differ according to a set of covariates. A bootstrap test for the model is …


Positive Solutions Of A Nonlinear N-Th Order Eigenvalue Problem, John R. Graef, Johnny Henderson, Bo Yang Oct 2006

Positive Solutions Of A Nonlinear N-Th Order Eigenvalue Problem, John R. Graef, Johnny Henderson, Bo Yang

Faculty Articles

For 1/2 < p < 1 fixed, values of lambda > 0 are determined for which there exist positive solutions of the n-th order differential equation u((n)) = lambda g(t)f(u), 0 < t < 1, satisfying the three-point boundary conditions, u((i-1)) (0) = u((n-2)) (P) = u((n-1)) (1) = 0, 1

The problem is converted to a third order differential-integro boundary value problem and then a recent result of Graef and Yang for third order boundary value problems is adapted. An example is included to illustrate the results.


An Elliptic Equation With No Monotonicity Condition On The Nonlinearity, Gregory S. Spradlin Oct 2006

An Elliptic Equation With No Monotonicity Condition On The Nonlinearity, Gregory S. Spradlin

Mathematics - Daytona Beach

An elliptic PDE is studied which is a perturbation of an autonomous equation. The existence of a nontrivial solution is proven via variational methods. The domain of the equation is unbounded, which imposes a lack of compactness on the variational problem. In addition, a popular monotonicity condition on the nonlinearity is not assumed. In an earlier paper with this assumption, a solution was obtained using a simple application of topological (Brouwer) degree. Here, a more subtle degree theory argument must be used. © EDP Sciences, SMAI 2006.


Multiattribute Acceptance Sampling Plans., Anup Majumdar Dr. Sep 2006

Multiattribute Acceptance Sampling Plans., Anup Majumdar Dr.

Doctoral Theses

Irrespective of the type of product, evaluation of conformity to specified requirements of its quality characteristics is an integral part of quality assurance. Although they form a set of necessary verification activities almost at all stages of production, these activities, known as inspection do not add value to the product on their own and are to be kept at their minimum. The sampling inspection where a portion of a collection of product units is inspected on a set of characteristics with a view to making decision about acceptance or otherwise becomes relevant in this context.The number of elements of the …


Norming Algebras And Automatic Complete Boundedness Of Isomorphisms Of Operator Algebras, David R. Pitts Sep 2006

Norming Algebras And Automatic Complete Boundedness Of Isomorphisms Of Operator Algebras, David R. Pitts

Department of Mathematics: Faculty Publications

We combine the notion of norming algebra introduced by Pop, Sinclair and Smith with a result of Pisier to show that if A1 and A2 are operator algebras, then any bounded epimorphism of A1 onto A2 is completely bounded provided that A2 contains a norming C*-subalgebra. We use this result to give some insights into Kadison’s Similarity Problem: we show that every faithful bounded homomorphism of a C*-algebra on a Hilbert space has completely bounded inverse, and show that a bounded representation of a C-algebra is similar to a -representation precisely when the image operator algebra -norms itself. We give …


Composition Operators With Maximal Norm On Weighted Bergman Spaces, Brent J. Carswell, Christopher Hammond Sep 2006

Composition Operators With Maximal Norm On Weighted Bergman Spaces, Brent J. Carswell, Christopher Hammond

Mathematics Faculty Publications

We prove that any composition operator with maximal norm on one of the weighted Bergman spaces is induced by a disk automorphism or a map that fixes the origin. This result demonstrates a major difference between the weighted Bergman spaces and the Hardy space H2, where every inner function induces a composition operator with maximal norm.


Robustness With Respect To Sampling For Stabilization Of Riesz Spectral Systems, Richard Rebarber, Stuart Townley Sep 2006

Robustness With Respect To Sampling For Stabilization Of Riesz Spectral Systems, Richard Rebarber, Stuart Townley

Department of Mathematics: Faculty Publications

We suppose that a continuous-time feedback is input–output stabilizing for an infinite-dimensional system. We address the question of whether the sampled-data controller obtained by applying idealized sample-and-hold to this continuous-time feedback is also input–output stabilizing if the sampling time is small enough. This question has been previously addressed for fairly general systems under various conditions. In this note, we restrict our attention to Riesz spectral systems, for which we generalize the existing results. Specifically, we give two relatively simple conditions which, combined, are sufficient for the sampled-data controller to be stabilizing. The first condition is a spectrum decomposition for the …


Necessary Conditions In Multiobjective Optimization With Equilibrium Constraints, Truong Q. Bao, Panjak Gupta, Boris S. Mordukhovich Sep 2006

Necessary Conditions In Multiobjective Optimization With Equilibrium Constraints, Truong Q. Bao, Panjak Gupta, Boris S. Mordukhovich

Mathematics Research Reports

In this paper we study multiobjective optimization problems with equilibrium constraints (MOECs) described by generalized equations in the form 0 is an element of the set G(x,y) + Q(x,y), where both mappings G and Q are set-valued. Such models particularly arise from certain optimization-related problems governed by variational inequalities and first-order optimality conditions in nondifferentiable programming. We establish verifiable necessary conditions for the general problems under consideration and for their important specifications using modern tools of variational analysis and generalized differentiation. The application of the obtained necessary optimality conditions is illustrated by a numerical example from bilevel programming with convex …


N–Localization Property, Andrzej Rosłanowski Sep 2006

N–Localization Property, Andrzej Rosłanowski

Mathematics Faculty Publications

This paper is concerned with n–localization property introduced by Newelski and Roslanowski in [10] and getting it for CS iterations of forcing notions.


Induction Of Characters And Finite P-Groups, Edith Adan-Bante Sep 2006

Induction Of Characters And Finite P-Groups, Edith Adan-Bante

Faculty Publications

Let G be a finite p-group, where p is an odd prime number, H be a subgroup of G and θ ∈ Irr(H) be an irreducible character of H. Assume also that | G : H | = p2. Then the character θG of G induce by θ is either a multiple of an irreducible character of G, or has at least p+1/2 distinct irreducible constituents.


Lowness And Π Nullsets, Rod Downey, Andre Nies, Rebecca Weber, Liang Yu Sep 2006

Lowness And Π Nullsets, Rod Downey, Andre Nies, Rebecca Weber, Liang Yu

Dartmouth Scholarship

We prove that there exists a noncomputable c.e. real which is low for weak 2-randomness, a definition of randomness due to Kurtz, and that all reals which are low for weak 2-randomness are low for Martin-Lof randomness.