Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons™

Open Access. Powered by Scholars. Published by Universities.®

2003

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 2821 - 2850 of 3876

Full-Text Articles in Physical Sciences and Mathematics

The Structure Of Residuated Lattices, Kevin K. Blount, Constantine Tsinakis Jan 2003

The Structure Of Residuated Lattices, Kevin K. Blount, Constantine Tsinakis

Mathematics Faculty Publications

A residuated lattice is an ordered algebraic structure [formula] such that is a lattice, is a monoid, and \ and / are binary operations for which the equivalences [formula] hold for all a,b,c ∈ L. It is helpful to think of the last two operations as left and right division and thus the equivalences can be seen as "dividing" on the right by b and "dividing" on the left by a. The class of all residuated lattices is denoted by ℛℒ The study of such objects originated in the context of the theory of ring ideals in the 1930s. The …

Go to article

Comparison Of The Theoretical And Experimental Band Structure Of Poly(Vinylidene Fluoride) Crystal, Chun-Gang Duan, Wai-Ning Mei, J.R. Hardy, Stephen Ducharme, Jaewu Choi, Peter A. Dowben Jan 2003

Comparison Of The Theoretical And Experimental Band Structure Of Poly(Vinylidene Fluoride) Crystal, Chun-Gang Duan, Wai-Ning Mei, J.R. Hardy, Stephen Ducharme, Jaewu Choi, Peter A. Dowben

Stephen Ducharme Publications

The electronic structure and band symmetries of the ferroelectric phase of poly (vinylidene fluoride) (PVDF) are studied by using the first-principles density-functional method. Our calculated results agree well with the angle-resolved photoemission experiments. We find that the PVDF crystal has an energy gap of about 6 eV at the Γ-point. Large dispersion of the valence band is found only along the chain direction, which is consistent with the quasi-one-dimensional nature of PVDF. In particular, the band symmetries of the valence states deduced theoretically are in good agreement with experiment. Finally, further investigations on the electronic structure of poly(trifluoroethylene) (PTrFE) …

Go to article

Phase Transitions Occurring In Models Of Neighborhood Racial Segregation, Alexander J. Laurie '03 Jan 2003

Phase Transitions Occurring In Models Of Neighborhood Racial Segregation, Alexander J. Laurie '03

Honors Projects

This thesis is organized as two chapters whose contents are closely related yet quite distinct. The first chapter presents a paper "Role of 'Vision' in Neighborhood Racial Segregation: A Variant of the Schelling Segregation Model," authored by myself and Dr. Jaggi, which has been accepted for publication by the journal Urban Studies and is currently in press (as of April 2003). This chapter introduces the well-known Schelling model of neighborhood segregation, outlines the sociopolitical motivation for our work, and presents the key results that we believe are of interest to social scientists. Chapter two, which ought to be of greater …

Go to article

Human Impact On Karst: The Example Of Lusaka (Zambia), Jo De Waele, Roberto Follesa Jan 2003

Human Impact On Karst: The Example Of Lusaka (Zambia), Jo De Waele, Roberto Follesa

International Journal of Speleology

Lusaka, the capital of Zambia with over 2,000,000 inhabitants, is built on an extensive plateau composed mainly of schists and dolomitic marbles, constituting a very important aquifer that provides the city with almost half of its drinking water needs. Recent demographic growth, leading to uncontrolled urban expansion, and mismanagement of the water resource and of urban waste has lead, in the past 20 years, to an overexploitation of the aquifer and to a generalised water quality depletion, putting in serious danger the future social and economical development of the capital. This third world city has, for these reasons, become a …

Go to article

The Effect Of The Domain Topology On The Number Of Minimal Nodal Solutions Of An Elliptic Equation At Critical Growth In A Symmetric Domain, Alfonso Castro, Mónica Clapp Jan 2003

The Effect Of The Domain Topology On The Number Of Minimal Nodal Solutions Of An Elliptic Equation At Critical Growth In A Symmetric Domain, Alfonso Castro, Mónica Clapp

All HMC Faculty Publications and Research

We consider the Dirichlet problem Δu + λu + |u|2*−2u = 0 in Ω, u = 0 on ∂Ω where Ω is a bounded smooth domain in RN, N≥4, and 2* = 2N/(N−2) is the critical Sobolev exponent. We show that if Ω is invariant under an orthogonal involution then, for λ>0 sufficiently small, there is an effect of the equivariant topology of Ω on the number of solutions which change sign exactly once.

Go to article

Breakdown Of The Slowly Varying Amplitude Approximation: Generation Of Backward Traveling Second Harmonic Light, J. Z. Sanborn '01, C. Hellings '02, Thomas D. Donnelly Jan 2003

Breakdown Of The Slowly Varying Amplitude Approximation: Generation Of Backward Traveling Second Harmonic Light, J. Z. Sanborn '01, C. Hellings '02, Thomas D. Donnelly

All HMC Faculty Publications and Research

By numerically solving the nonlinear field equations, we simulate second-harmonic generation by laser pulses within a nonlinear medium without making the usual slowly-varying-amplitude approximation, an approximation which may fail when laser pulses of moderate intensity or ultrashort duration are used to drive a nonlinear process. Under these conditions we show that a backward-traveling, second-harmonic wave is created, and that the magnitude of this wave is indicative of the breakdown of the slowly-varying-amplitude approximation. Conditions necessary for experimental detection of this wave are discussed.

Go to article

Holography With Ramond-Ramond Fluxes, Vatche Sahakian Jan 2003

Holography With Ramond-Ramond Fluxes, Vatche Sahakian

All HMC Faculty Publications and Research

Starting from the non-linear sigma model of the IIB string in the light-cone gauge, we analyze the role of RR fluxes in Holography. We find that the worldsheet theory of states with only left or right moving modes does not see the presence of RR fields threading a geometry. We use this significant simplification to compute part of the strong coupling spectrum of the two dimensional NCOS theory. We also reproduce the action of a closed string in a PP-wave background using this general formalism; and we argue for various strategies to find new systems where the closed string theory …

Go to article

Spaces X In Which All Prime Z-Ideals Of C(X) Are Minimal Or Maximal, Melvin Henriksen, Jorge Martinez, R. G. Woods Jan 2003

Spaces X In Which All Prime Z-Ideals Of C(X) Are Minimal Or Maximal, Melvin Henriksen, Jorge Martinez, R. G. Woods

All HMC Faculty Publications and Research

Quasi P-spaces are defined to be those Tychonoff spaces X such that each prime z-ideal of C(X) is either minimal or maximal. This article is devoted to a systematic study of these spaces, which are an obvious generalization of P-spaces. The compact quasi P-spaces are characterized as the compact spaces which are scattered and of Cantor-Bendixson index no greater than 2. A thorough account of locally compact quasi P-spaces is given. If X is a cozero-complemented space and every nowhere dense zeroset is a z-embedded P-space, then X is a quasi P-space. Conversely, if X is a quasi P-space and …

Go to article

Cover - Table Of Contents Jan 2003

Cover - Table Of Contents

Journal of the Iowa Academy of Science: JIAS

No abstract provided.

Go to article

Software Requirements Specification Of A University Class Scheduler, Sergiu M. Dascalu, Fredrick C. Harris Jr., Deanna Needell, Jeff A. Stuart, Tamara C. Thiel Jan 2003

Software Requirements Specification Of A University Class Scheduler, Sergiu M. Dascalu, Fredrick C. Harris Jr., Deanna Needell, Jeff A. Stuart, Tamara C. Thiel

CMC Faculty Publications and Research

The University Class Scheduler (UCS) presented in this paper is a novel scheduling tool intended to be used by universities to schedule classes into classrooms. In essence, UCS allows university administrators to enter relevant college and building information, schedule the input classes (courses) into input classrooms, and create web pages that provide detailed schedule information on a semester-by-semester basis. The UCS, which performs the scheduling of classes according to a number of user-selected parameters, can be easily adapted for applications outside the academic realm. This paper presents the main aspects of the University Class Scheduler’s UML-based specification, gives details of …

Go to article

Creating Monolayers And Thin Films Of A Novel Bis(Alkyl) Substituted Asymmetrical Polyoxotungstate, {[Ch3(Ch2)11si]2osiw11o39}42 Using The Langmuir–Blodgett Technique, R. Carlisle Chambers, Elizabeth J. Osburn Atkinson, David Mcadams, Eric J. Hayden, Davida Ankeny Brown Jan 2003

Creating Monolayers And Thin Films Of A Novel Bis(Alkyl) Substituted Asymmetrical Polyoxotungstate, {[Ch3(Ch2)11si]2osiw11o39}42 Using The Langmuir–Blodgett Technique, R. Carlisle Chambers, Elizabeth J. Osburn Atkinson, David Mcadams, Eric J. Hayden, Davida Ankeny Brown

Faculty Publications - Department of Biological & Molecular Science

No abstract provided.

Go to article

Hypothalamic Proopiomelanocortin Neurons Are Glucose Responsive And Express Katp Channels, Nurhadi Ibrahim, Martha A. Bosch, James L. Smart, Jian Qiu, Marcelo Rubinstein, Oline K. Rønnekleiv, Malcolm J. Low, Martin J. Kelly Jan 2003

Hypothalamic Proopiomelanocortin Neurons Are Glucose Responsive And Express Katp Channels, Nurhadi Ibrahim, Martha A. Bosch, James L. Smart, Jian Qiu, Marcelo Rubinstein, Oline K. Rønnekleiv, Malcolm J. Low, Martin J. Kelly

Faculty Publications - Department of Biological & Molecular Science

Hypothalamic proopiomelanocortin (POMC) neurons are critical for controlling homeostatic functions in the mammal. We used a transgenic mouse model in which the POMC neurons were labeled with enhanced green fluorescent protein to perform visualized, whole-cell patch recordings from prepubertal female hypothalamic slices. The mouse POMC-enhanced green fluorescent protein neurons expressed the same endogenous conductances (a transient outward K current and a hyperpolarization-activated, cation current) that have been described for guinea pig POMC neurons. In addition, the selective -opioid receptor agonist DAMGO induced an outward current (maximum of 12.8 1.2 pA), which reversed at K equilibrium potential (EK), in the majority …

Go to article

An Additive Schwarz Preconditioner For The Spectral Element Ocean Model Formulation Of The Shallow Water Equations, Craig C. Douglas, Gundolf Haase, Mohamed Iskandarani Jan 2003

An Additive Schwarz Preconditioner For The Spectral Element Ocean Model Formulation Of The Shallow Water Equations, Craig C. Douglas, Gundolf Haase, Mohamed Iskandarani

Computer Science Faculty Publications

We discretize the shallow water equations with an Adams-Bashford scheme combined with the Crank-Nicholson scheme for the time derivatives and spectral elements for the discretization in space. The resulting coupled system of equations will be reduced to a Schur complement system with a special structure of the Schur complement. This system can be solved with a preconditioned conjugate gradients, where the matrix-vector product is only implicitly given. We derive an overlapping block preconditioner based on additive Schwarz methods for preconditioning the reduced system.

Go to article

Planar Minimally Rigid Graphs And Pseudo-Triangulations, Ruth Haas, David Orden, Günter Rote, Francisco Santos, Herman Servatius, Diane Souvaine, Ileana Streinu, Walter Whiteley Jan 2003

Planar Minimally Rigid Graphs And Pseudo-Triangulations, Ruth Haas, David Orden, Günter Rote, Francisco Santos, Herman Servatius, Diane Souvaine, Ileana Streinu, Walter Whiteley

Mathematics Sciences: Faculty Publications

Pointed pseudo-triangulations are planar minimally rigid graphs embedded in the plane with pointed vertices (adjacent to an angle larger than π). In this paper we prove that the opposite statement is also true, namely that planar minimally rigid graphs always admit pointed embeddings, even under certain natural topological and combinatorial constraints. The proofs yield efficient embedding algorithms. They also provide - to the best of our knowledge - the first algorithmically effective result on graph embeddings with oriented matroid constraints other than convexity of faces. These constraints are described by combinatorial pseudo-triangulations, first defined and studied in this paper. Also …

Go to article

Unification Scale, Proton Decay, And Manifolds Of G2 Holonomy, Tamar Friedmann, Edward Witten Jan 2003

Unification Scale, Proton Decay, And Manifolds Of G2 Holonomy, Tamar Friedmann, Edward Witten

Mathematics Sciences: Faculty Publications

Models of particle physics based on manifolds of G2 holonomy are in most respects much more complicated than other string-derived models, but as we show here they do have one simplification: threshold corrections to grand unification are particularly simple. We compute these corrections, getting completely explicit results in some simple cases. We estimate the relation between Newton’s constant, the GUT scale, and the value of αGUT , and explore the implications for proton decay. In the case of proton decay, there is an interesting mechanism which (relative to four-dimensional SUSY GUT’s) enhances the gauge boson contribution to p → π …

Go to article

A Dynamical System For Plant Pattern Formation: A Rigorous Analysis, Pau Atela, Christophe Golé, S. Hotton Jan 2003

A Dynamical System For Plant Pattern Formation: A Rigorous Analysis, Pau Atela, Christophe Golé, S. Hotton

Mathematics Sciences: Faculty Publications

We present a rigorous mathematical analysis of a discrete dynamical system modeling plant pattern formation. In this model, based on the work of physicists Douady and Couder, fixed points are the spiral or helical lattices often occurring in plants. The frequent occurrence of the Fibonacci sequence in the number of visible spirals is explained by the stability of the fixed points in this system, as well as by the structure of their bifurcation diagram. We provide a detailed study of this diagram.

Go to article

Regularity Of Minimizers Of The Calculus Of Variations In Carnot Groups Via Hypoellipticity Of Systems Of Hörmander Type, Luca Capogna, Nicola Garofalo Jan 2003

Regularity Of Minimizers Of The Calculus Of Variations In Carnot Groups Via Hypoellipticity Of Systems Of Hörmander Type, Luca Capogna, Nicola Garofalo

Mathematics Sciences: Faculty Publications

We prove the hypoellipticity for systems of Hörmander type with constant coefficients in Carnot groups of step 2. This result is used to implement blow-up methods and prove partial regularity for local minimizers of non-convex functionals, and for solutions of non-linear systems which appear in the study of non-isotropic metric structures with scalings. We also establish estimates of the Hausdorff dimension of the singular set.

Go to article

Long Time Behavior Of Solutions To The 3d Compressible Euler Equations With Damping, Thomas C. Sideris, Becca Thomases, Dehua Wang Jan 2003

Long Time Behavior Of Solutions To The 3d Compressible Euler Equations With Damping, Thomas C. Sideris, Becca Thomases, Dehua Wang

Mathematics Sciences: Faculty Publications

The effect of damping on the large-time behavior of solutions to the Cauchy problem for the three-dimensional compressible Euler equations is studied. It is proved that damping prevents the development of singularities in small amplitude classical solutions, using an equivalent reformulation of the Cauchy problem to obtain effective energy estimates. The full solution relaxes in the maximum norm to the constant background state at a rate of t-3/2. While the fluid vorticity decays to zero exponentially fast in time, the full solution does not decay exponentially. Formation of singularities is also exhibited for large data.

Go to article

Ua1bc Final Report Of 2002-2003 Wku Technology Advisory Council Meetings, Western Kentucky University Jan 2003

Ua1bc Final Report Of 2002-2003 Wku Technology Advisory Council Meetings, Western Kentucky University

WKU Archives Records

The WKU Technology Advisory Council was established on November 8, 2002. It is comprised of faculty, deans, department heads, directors and students. This report contains summaries of meeting minutes and list of committee members.

Go to article

The Embedding Of Complete Bipartite Graphs Onto Grids With A Minimum Grid Cutwidth, Mário Rocha Jan 2003

The Embedding Of Complete Bipartite Graphs Onto Grids With A Minimum Grid Cutwidth, Mário Rocha

Theses Digitization Project

Algorithms will be domonstrated for how to embed complete bipartite graphs onto 2xn type grids, where the imimum grid cutwidth is attained.

Go to article

The Window Least Mean Square Error Algorithm, Anna Semenovna Degtyarena Jan 2003

The Window Least Mean Square Error Algorithm, Anna Semenovna Degtyarena

Theses Digitization Project

In order to improve the performance of LMS (least mean square) algorithm by decreasing the amount of calculations this research proposes to make an update on each step only for those elements from the input data set, that fall within a small window W near the separating hyperplane surface. This work aims to describe in detail the results that can be achieved by using the proposed LMS with window learning algorithm in information systems that employ the methodology of neural network for the purposes of classification.

Go to article

Prescription Express System, Chia-Yu Tsai Jan 2003

Prescription Express System, Chia-Yu Tsai

Theses Digitization Project

The Prescription Express System is a software program that was developed with express service of health care in mind. The purpose was to provide easy access for doctors to check on upcoming appointments with patients and send prescriptions via wireless network directly to the pharmacy to provide faster service.

Go to article

Telephone Directory Web Service, Hua Sun Jan 2003

Telephone Directory Web Service, Hua Sun

Theses Digitization Project

This was a project to develop a Telephone Directory Web service (TDWS) to provide convenient and cost-effective access to public telephone directory data.

Go to article

The Mathematics Of Object Recognition In Machine And Human Vision, Sunyoung Kim Jan 2003

The Mathematics Of Object Recognition In Machine And Human Vision, Sunyoung Kim

Theses Digitization Project

The purpose of this project was to see why projective geometry is related to the sort of sensors that machines and humans use for vision.

Go to article

A Parallel Algorithm To Solve The Mathematical Problem "Double Coset Enumeration Of S₂₄ Over M₂₄", Elena Yavorska Harris Jan 2003

A Parallel Algorithm To Solve The Mathematical Problem "Double Coset Enumeration Of S₂₄ Over M₂₄", Elena Yavorska Harris

Theses Digitization Project

This thesis presents and evaluates a new parallel algorithm that computes all single cosets in the double coset M₂₄ P M₂₄, where P is a permutation on n points of a certain cycle structure, and M₂₄ is the Mathieu group related to a Steiner system S(5, 8, 24) as its automorphism group. The purpose of this work is not to replace the existing algorithms, but rather to explore a possibility to extend calculations of single cosets beyond the limits encountered when using currently available methods.

Go to article

Wiki-Style Administration Of Online Course Content, Jianmin Wang Jan 2003

Wiki-Style Administration Of Online Course Content, Jianmin Wang

Theses Digitization Project

A Wiki is a piece of server software that allows users to freely create and edit Web page content using any Web browser. This project created the program, "Wiki-Style Administration of Online Course Content" (WAOCC) which can be used as a teaching assistant board. Students can edit their works online and the instructor can review the work and correct it directly if necessary from the WAOCC.

Go to article

Web-Based E-Mail Client For Computer Science, Jichuan Wu Jan 2003

Web-Based E-Mail Client For Computer Science, Jichuan Wu

Theses Digitization Project

The project is a web e-mail application to provide a web page interface for all CSCI faculty, staff and students to handle their e-mails. The application is written by JSP, Java Servlets, JavaScript and custom JSP tag libraries. Regular e-mail capabilities have been enhanced by the feature of allowing users to store and manage messages by day (store to daily folders, view in daily folders, append notes for that day).

Go to article

Stream Bank Stability In Eastern Nebraska, Philip J. Soenksen, Mary J. Turner, Benjamin J. Dietsch, Andrew Simon Jan 2003

Stream Bank Stability In Eastern Nebraska, Philip J. Soenksen, Mary J. Turner, Benjamin J. Dietsch, Andrew Simon

United States Geological Survey: Publications

Dredged and straightened channels in eastern Nebraska have experienced degradation leading to channel widening by bank failure. Degradation has progressed headward and affected the drainage systems upstream from the modified reaches. This report describes a study that was undertaken to analyze bank stability at selected sites in eastern Nebraska and develop a simplified method for estimating the stability of banks at future study sites. Bank cross sections along straight reaches of channel and geotechnical data were collected at approximately 150 sites in 26 counties of eastern Nebraska. The sites were categorized into three groups based on mapped soil permeability. With …

Go to article

Monitoring Trends In Bat Populations Of The United States And Territories: Problems And Prospects, T. J. O'Shea, M.A. Bogan Jan 2003

Monitoring Trends In Bat Populations Of The United States And Territories: Problems And Prospects, T. J. O'Shea, M.A. Bogan

United States Geological Survey: Publications

Bats are ecologically and economically important mammals. The life histories of bats (particularly their low reproductive rates and the need for some species to gather in large aggregations at limited numbers of roosting sites) make their populations vulnerable to declines. Many of the species of bats in the United States (U.S.) and territories are categorized as endangered or threatened, have been candidates for such categories, or are considered species of concern. The importance and vulnerability of bat populations makes monitoring trends in their populations a goal for their future management. However, scientifically rigorous monitoring of bat populations requires well-planned, statistically …

Go to article

Streambed Adjustment And Channel Widening In Eastern Nebraska, David L. Rus, Benjamin J. Dietsch, Andrew Simon Jan 2003

Streambed Adjustment And Channel Widening In Eastern Nebraska, David L. Rus, Benjamin J. Dietsch, Andrew Simon

United States Geological Survey: Publications

In eastern Nebraska, stream straightening and dredging efforts since the 1890s have disturbed the natural equilibrium of stream channels and have led to streambed adjustment by degradation and subsequent channel widening. This report describes a study to evaluate the effect these disturbances have had on stream channels in eastern Nebraska.

Two sets of survey data were collected approximately 2 years apart during 1996–99 at 151 primary sites. Additionally, historical streambed-elevation data (dating back to the 1890s) were compiled from several sources for the primary sites and 45 supplemental sites, and relevant disturbances were identified for each of eight basin groupings. …

Go to article

First Prev Next Last