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

Digital Commons Network™

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

2011

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 2971 - 3000 of 17415

Full-Text Articles in Entire DC Network

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.

Go to article

2011.09.15 Board Of Trustees Meeting Minutes, Northeastern Illinois University Board Of Trustees Sep 2011

2011.09.15 Board Of Trustees Meeting Minutes, Northeastern Illinois University Board Of Trustees

Board of Trustees - 2011

Meeting materials for the NEIU Board of Trustees

Go to article

The Pacifican September 15, 2011, University Of The Pacific Sep 2011

The Pacifican September 15, 2011, University Of The Pacific

All Issues - Student Newspaper, The Pacifican, Pacific Weekly

No abstract provided.

Go to article

Vista: September 15, 2011, University Of San Diego Sep 2011

Vista: September 15, 2011, University Of San Diego

USD Vista (1965-)

No abstract provided.

Go to article

The Grizzly, September 15, 2011, Liz Kilmer, Nick Pane, Ron Stranix, Jenna Yaich, Lisa Jobe, Lauren Tedesco, Pearl Steinberg, Marina Mccann, Annabel Clarance, Dave Muoio, Lauren Goldstein, Rosemary Clark, Kyu Chul Shin, Jacquelyn Heikel, Connor Gregory, Victoria Cameron Sep 2011

The Grizzly, September 15, 2011, Liz Kilmer, Nick Pane, Ron Stranix, Jenna Yaich, Lisa Jobe, Lauren Tedesco, Pearl Steinberg, Marina Mccann, Annabel Clarance, Dave Muoio, Lauren Goldstein, Rosemary Clark, Kyu Chul Shin, Jacquelyn Heikel, Connor Gregory, Victoria Cameron

Ursinus College Grizzly Newspaper, 1978 to Present

New CAB Events Coming This Fall • UC Commemorates 9/11 • CAB Hosts Activities Fair in Zack's • GSA Welcomes New Board • Tips to Assist with Time Management • New Math Professor Brings Biostatistics Expertise • Peer Docent Program Returns to Berman • Senior Reminisces on Semester Spent Abroad • Opinions: Updated Sexual Assault Policy Needs Awareness; Libya Should Look to Spain When Rebuilding Government • Fast Start has Volleyball on Track for the Playoffs • Cross Country Eyes Continued Improvement in 2011 • Men's Basketball Team Goes Abroad

Go to article

The Parthenon, September 15, 2011, Kristin Steele Sep 2011

The Parthenon, September 15, 2011, Kristin Steele

The Parthenon

The Parthenon, Marshall University’s student newspaper, is published by students Monday through Friday during the regular semester and weekly Thursday during the summer. The editorial staff is responsible for the news and the editorial content.

Go to article

Two-Dimensional, Time-Dependent Plasma Structures Of A Hall Effect Thruster, David Liu Sep 2011

Two-Dimensional, Time-Dependent Plasma Structures Of A Hall Effect Thruster, David Liu

Theses and Dissertations

The Hall thruster is a type of electric propulsion utilized by satellites to perform a wide variety of missions ranging from station keeping, orbital maneuvers, and even deep space propulsion. In order to accommodate the multitude of missions it also has a wide assortment of sizes and power configurations which can range from approximately an inch in diameter at 20 W to a couple of feet in diameter at 1.5 kW. Additionally, this electro-static device provides high specific impulse without the added weight penalty associated with conventional chemical thrusters. It supplies this high specific impulse by ionizing a gas such …

Go to article

Increasing The Performance Of A Sliding Discharge Actuator Through The Application Of Multiple Potentials, Steven D. Seney Jr. Sep 2011

Increasing The Performance Of A Sliding Discharge Actuator Through The Application Of Multiple Potentials, Steven D. Seney Jr.

Theses and Dissertations

This work encompasses a comparison between a sliding discharge DBD actuator with grounded and AC biased sliding electrode driven at kHz frequency. The induced velocity in the bulk flow was recorded with PIV and compared for multiple potential splits between two test configurations and a baseline sliding discharge actuator over three test phases. In the first test phase, varying potential splits were examined between the primary and secondary electrode with the sliding electrode grounded. The potential splits induced a thicker induced jet than the baseline case with similar peak velocities on the order of 1.25 m/s at the 61 mm …

Go to article

Distributed Spacing Stochastic Feature Selection And Its Application To Textile Classification, Jeffrey D. Clark Sep 2011

Distributed Spacing Stochastic Feature Selection And Its Application To Textile Classification, Jeffrey D. Clark

Theses and Dissertations

Many situations require the need to quickly and accurately locate dismounted individuals in a variety of environments. In conjunction with other dismount detection techniques, being able to detect and classify clothing (textiles) provides a more comprehensive and complete dismount characterization capability. Because textile classification depends on distinguishing between different material types, hyperspectral data, which consists of several hundred spectral channels sampled from a continuous electromagnetic spectrum, is used as a data source. However, a hyperspectral image generates vast amounts of information and can be computationally intractable to analyze. A primary means to reduce the computational complexity is to use feature …

Go to article

A Novel Malware Target Recognition Architecture For Enhanced Cyberspace Situation Awareness, Thomas E. Dube Sep 2011

A Novel Malware Target Recognition Architecture For Enhanced Cyberspace Situation Awareness, Thomas E. Dube

Theses and Dissertations

The rapid transition of critical business processes to computer networks potentially exposes organizations to digital theft or corruption by advanced competitors. One tool used for these tasks is malware, because it circumvents legitimate authentication mechanisms. Malware is an epidemic problem for organizations of all types. This research proposes and evaluates a novel Malware Target Recognition (MaTR) architecture for malware detection and identification of propagation methods and payloads to enhance situation awareness in tactical scenarios using non-instruction-based, static heuristic features. MaTR achieves a 99.92% detection accuracy on known malware with false positive and false negative rates of 8.73e-4 and 8.03e-4 respectively. …

Go to article

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 …

Go to article

Integrated Approach To Free Space Optical Communications In Strong Turbulence, Jason A. Tellez Sep 2011

Integrated Approach To Free Space Optical Communications In Strong Turbulence, Jason A. Tellez

Theses and Dissertations

The propagation of a free space optical communication signal through atmospheric turbulence experiences random fluctuations in intensity, including signal fades which negatively impact the communications link performance. This research develops an analytical probability density function (PDF) to model the best case scenario of using multiple independent beams to reduce the intensity fluctuations. The PDF was further developed to account for partially correlated beams, such as would be experienced by beams having finite separation. The PDF was validated with results obtained from digital simulations as well as lab experiments. The research showed that as the number of transmitted beams increases the …

Go to article

Detecting Man-In-The-Middle Attacks Against Transport Layer Security Connections With Timing Analysis, Lauren M. Wagoner Sep 2011

Detecting Man-In-The-Middle Attacks Against Transport Layer Security Connections With Timing Analysis, Lauren M. Wagoner

Theses and Dissertations

The Transport Layer Security (TLS) protocol is a vital component to the protection of data as it traverses across networks. From e-commerce websites to Virtual Private Networks (VPNs), TLS protects massive amounts of private information, and protecting this data from Man-in-the-Middle (MitM) attacks is imperative to keeping the information secure. This thesis illustrates how an attacker can successfully perform a MitM attack against a TLS connection without alerting the user to his activities. By deceiving the client machine into using a false certificate, an attacker takes away the only active defense mechanism a user has against a MitM. The goal …

Go to article

Modeling Self-Referencing Interferometers With Extended Beacons And Strong Turbulence, Daniel J. Wheeler Sep 2011

Modeling Self-Referencing Interferometers With Extended Beacons And Strong Turbulence, Daniel J. Wheeler

Theses and Dissertations

The overall purpose of this research was to better understand the performance of a self-referencing interferometer (SRI) when used with extended beacons in strong atmospheric turbulence. It was performed by assuming the extended beacon could be modeled as a Gaussian Schell-model beam, then analyzing the effect of propagating this beam through strong atmospheric turbulence. Since the operation of an SRI requires coupling this light into a single-mode optical fiber, analytic expressions of the mean and normalized variance of the coupling efficiency were derived. An improved noise model for the SRI was then developed that included all potential noise sources such …

Go to article

Verification Of Global Assimilation Of Ionospheric Measurements Gauss Markov (Gaim-Gm) Model Forecast Accuracy, Paul H. Domm Sep 2011

Verification Of Global Assimilation Of Ionospheric Measurements Gauss Markov (Gaim-Gm) Model Forecast Accuracy, Paul H. Domm

Theses and Dissertations

GAIM-GM is an operational Kalman filter data assimilation model of the ionosphere that can assimilate data from GPS total electron content (TEC), ionosonde electron density profiles, and satellite based in situ electron densities. The Air Force Weather Agency (AFWA) uses GAIM-GM to specify and forecast the ionosphere. An in depth investigation into the accuracy of these forecasts has not been completed. GAIM-GM output obtained from four cases run from combinations of geomagnetic and solar activity was used to determine GAIM-GM forecast accuracy. Forecast accuracy was determined through the use of a skill score as well as other statistical tools to …

Go to article

Assessment Of The Effects Of Plasma Bubbles On Gaim-Gm, Kenneth R. Fenton Sep 2011

Assessment Of The Effects Of Plasma Bubbles On Gaim-Gm, Kenneth R. Fenton

Theses and Dissertations

Plasma bubbles are regions of depleted plasma density generated in the post-sunset equatorial region of the ionosphere. Bubbles significantly affect total electron count (TEC) and consequently alter communication and navigation capabilities. Here, the Global Assimilation of Ionospheric Measurements Gauss-Markov (GAIM-GM) model is studied in order to assess its capability to accurately model equatorial plasma bubbles. GAIM-GM uses the Ionospheric Forecast Model (IFM) as a background state modified through the application of a Kalman Filter to incorporate ionospheric observations such as Global Positioning System (GPS) total electron content (TEC) values. GPS TEC values representative of plasma bubble conditions are modeled and …

Go to article

The Effects Of Rare Earth Doping On Gallium Nitride Thin Films, Stephen R. Mchale Sep 2011

The Effects Of Rare Earth Doping On Gallium Nitride Thin Films, Stephen R. Mchale

Theses and Dissertations

The thermal neutron capture cross section of the rare earth (RE) metal isotope Gd-157 is the largest of all known natural elements, which distinguishes the material as a logical candidate for neutron detection. To address an incomplete understanding of rare earth doped Gallium Nitride (GaN) materials, investigations of the surface electronic structure and interface properties of GaN thin films doped with rare earths (Yb, Er, Gd) were undertaken. Lattice ion occupation, bonding, rare earth 4f occupation, and gold Schottky barrier formation were examined using synchrotron photoemission spectroscopy. Measured Debye temperatures indicate substitutional occupation of Ga sites by RE ions. The …

Go to article

Source Normalization Constants For Ground Distributed Fallout Fields, Justin M. Smith Sep 2011

Source Normalization Constants For Ground Distributed Fallout Fields, Justin M. Smith

Theses and Dissertations

Five assumptions regarding a first order model developed to calculate dose rate at a detector above a fallout field are analyzed. The omission of scattering is relaxed by the method of successive scatters resulting in a build up factor of 1.1. The use of a single average photon energy to represent a fallout distribution is analyzed using the Oak Ridge National Laboratory Isotope Generator (ORIGEN) Fallout Analysis Tool. An average photon energy of 0.81MeV is calculated and shown to be an accurate approximation of the fallout field energy distribution. A Gaussian distribution is used to calculate the minimal impact of …

Go to article

Non-Adiabatic Atomic Transitions: Computational Cross Section Calculations Of Alkali Metal-Noble Gas Collisions, Charlton D. Lewis Ii Sep 2011

Non-Adiabatic Atomic Transitions: Computational Cross Section Calculations Of Alkali Metal-Noble Gas Collisions, Charlton D. Lewis Ii

Theses and Dissertations

Diode Pumped Alkali Lasers operate by exciting a gaseous cell of alkali metal to its P3/2 excited energy state. A noble gas, present in the cell, collisionally de-excites the alkali metal to its P1/2 state. The alkali atoms then relax to their S1/2 ground state by emitting photons. The non-radiative de-excitation due to inert gas atoms represents an interesting juncture for DPALs operation. This process must be faster than the radiative relaxation back to the S1/2 state for lasing to occur. The rate of non-radiative de-excitation is related to the collisional cross section and the cross …

Go to article

Effect Of Storm Enhanced Densities On Geo-Location Accuracy Over Conus, Lindon H. Steadman Sep 2011

Effect Of Storm Enhanced Densities On Geo-Location Accuracy Over Conus, Lindon H. Steadman

Theses and Dissertations

Storm enhanced densities (SEDs) are ionospheric plasma enhancements that disrupt radio communications in the near-Earth space environment, degrading the Global Positioning System (GPS) and other key technologies. Accurate GPS/total electron content (TEC) correction maps produced by ionosphere models can mitigate degradations from SEDs. An artificial SED was created and ingested via slant TEC measurements into the Global Assimilation of Ionospheric Measurements Gauss-Markov Kalman Filter Model to determine how many ground GPS receivers are needed to produce reliable GPS/TEC correction maps over the continental United States during geomagnetic storming. It was found that 110 well-positioned GPS receivers produced the best overall …

Go to article

Analysis Of Transient Electromagnetic Scattering From An Overfilled Cavity Embedded In An Impedance Ground Plane, Robert S. Callihan Sep 2011

Analysis Of Transient Electromagnetic Scattering From An Overfilled Cavity Embedded In An Impedance Ground Plane, Robert S. Callihan

Theses and Dissertations

We consider the transient, or time-domain, scattering problem of a two-dimensional overfilled cavity embedded in an impedance ground plane. This problem is a significant advancement from previous work where more simplified boundary conditions were used, which can limit the number of applications. This research supports a wide range of military applications such as the study of cavity-like structures on aircraft and vehicles. More importantly, this research helps detect the biggest threat on today's battlefield: improvised explosive devices. An important step in solving the problem is introducing an artificial boundary condition on a semicircle enclosing the cavity; this couples the fields …

Go to article

Identification And Classification Of Player Types In Massive Multiplayer Online Games Using Avatar Behavior, Earl M. Bednar Sep 2011

Identification And Classification Of Player Types In Massive Multiplayer Online Games Using Avatar Behavior, Earl M. Bednar

Theses and Dissertations

The purpose of our research is to develop an improved methodology for classifying players (identifying deviant players such as terrorists) through multivariate analysis of data from avatar characteristics and behaviors in massive multiplayer online games (MMOGs). To build our classification models, we developed three significant enhancements to the standard Generalized Regression Neural Networks (GRNN) modeling method. The first enhancement is a feature selection technique based on GRNNs, allowing us to tailor our feature set to be best modeled by GRNNs. The second enhancement is a hybrid GRNN which allows each feature to be modeled by a GRNN tailored to its …

Go to article

Modeling And Analysis Of High Energy Laser Weapon System Performance In Varying Atmospheric Conditions, Megan P. Melin Sep 2011

Modeling And Analysis Of High Energy Laser Weapon System Performance In Varying Atmospheric Conditions, Megan P. Melin

Theses and Dissertations

This thesis addresses two primary concerns relating to Directed Energy (DE) models and tests: need for more use of Design of Experiment (DOE) in structuring DE models and tests, and lack of modeling atmospheric variability in High Energy Laser (HEL) weapon system propagation models and tests. To address these concerns we use a DOE factorial design to capture main, interaction, and non-linear effects between modeled weapon design and environmental factors in a well defined simulated Air-to-Ground HEL engagement scenario. The scenario modeled considers a B1-B aircraft in the 2022 timeframe equipped with an HEL weapon, irradiating a ground target from …

Go to article

An Empirical Analysis Of The Cascade Secret Key Reconciliation Protocol For Quantum Key Distribution, Timothy I. Calver Sep 2011

An Empirical Analysis Of The Cascade Secret Key Reconciliation Protocol For Quantum Key Distribution, Timothy I. Calver

Theses and Dissertations

The need to share key material with authorized entities in a secure, efficient and timely manner has driven efforts to develop new key distribution methods. The most promising method is Quantum Key Distribution (QKD) and is considered to be “unconditionally secure” because it relies upon the immutable laws of quantum physics rather than computational complexity. Unfortunately, the nonidealities present in actual implementations of QKD systems also result in errors manifested in the quantum data channel. As a consequence, an important component of any QKD system is the error reconciliation protocol which is used to identify and correct inconsistencies in the …

Go to article

The Inkwell, Armstrong Atlantic State University Sep 2011

The Inkwell, Armstrong Atlantic State University

The Inkwell

No abstract provided.

Go to article

Sparse Spectral-Tau Method For The Three-Dimensional Helically Reduced Wave Equation On Two-Center Domains, Stephen R. Lau, Richard H. Price Sep 2011

Sparse Spectral-Tau Method For The Three-Dimensional Helically Reduced Wave Equation On Two-Center Domains, Stephen R. Lau, Richard H. Price

Physics & Astronomy Faculty Publications

We describe a multidomain spectral-tau method for solving the three-dimensional helically reduced wave equation on the type of two-center domain that arises when modeling compact binary objects in astrophysical applications. A global two-center domain may arise as the union of Cartesian blocks, cylindrical shells, and inner and outer spherical shells. For each such subdomain, our key objective is to realize certain (differential and multiplication) physical-space operators as matrices acting on the corresponding set of modal coefficients. We then achieve sparse realizations through the integration “preconditioning” of Coutsias, Hagstrom, Hesthaven, and Torres. Since ours is the first three-dimensional multidomain implementation of …

Go to article

Kenyon Collegian - September 15, 2011 Sep 2011

Kenyon Collegian - September 15, 2011

The Kenyon Collegian

No abstract provided.

Go to article

Nota Bene, September 14, 2011 Sep 2011

Nota Bene, September 14, 2011

Nota Bene, 2011

No abstract provided.

Go to article

The Lumberjack, September 14, 2011 Sep 2011

The Lumberjack, September 14, 2011

Cal Poly Humboldt's Student Newspaper

The student newspaper of Humboldt State University.

Go to article

Reduction Of Anxiety In College Students With Asperger's Disorder Using Behavioral Relaxation Training, Jaclyn Bechtler Sep 2011

Reduction Of Anxiety In College Students With Asperger's Disorder Using Behavioral Relaxation Training, Jaclyn Bechtler

Theses and Dissertations

The purpose of this study was to reduce levels of anxiety in college students with Asperger's Disorder. Two students from Rowan University were taught Behavioral Relaxation Training over a period of four weeks. Measurements of anxiety and relaxation were gathered during biweekly sessions and those results were graphed. Results showed that a) behavioral relaxation training was quickly learned by participants and b) anxiety levels decreased on some measures with the use of behavioral relaxation. Issues facing those with Asperger's Disorder were discussed as well as the wide variety of populations that have demonstrated positive change with behavioral relaxation training.

Go to article

First Prev Next Last