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2003

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Articles 691 - 720 of 3876

Full-Text Articles in Physical Sciences and Mathematics

Faster Algorithms For K-Median Problem On Trees With Smaller Heights, Rahul Shah Sep 2003

Faster Algorithms For K-Median Problem On Trees With Smaller Heights, Rahul Shah

Department of Computer Science Technical Reports

No abstract provided.


Quasaq: A Database-Centric Approach To Enabling End-To-End Qos Control For Multimedia Repositories, Yi-Cheng Tu, Sunil Prabhakar, Ahmed K. Elmagarmid Sep 2003

Quasaq: A Database-Centric Approach To Enabling End-To-End Qos Control For Multimedia Repositories, Yi-Cheng Tu, Sunil Prabhakar, Ahmed K. Elmagarmid

Department of Computer Science Technical Reports

No abstract provided.


Mmse Design Of Redundant Fir Precoders For Arbitrary Channel Lengths, Alfred Mertins Sep 2003

Mmse Design Of Redundant Fir Precoders For Arbitrary Channel Lengths, Alfred Mertins

Faculty of Informatics - Papers (Archive)

The joint design of transmitter and receiver for multichannel data transmission over dispersive channels is considered. The design criterion is the minimization of the mean squared error (MSE) at the receiver output under the constraint of a fixed transmit power. The focus is on the practically important case where the transmitter employs finite impulse response (FIR) filters, and the channel impulse response has arbitrary length. The proposed algorithm allows a straightforward transmitter design and generally yields near-optimal solutions for the transmit filters. Under certain conditions, the exact solutions for optimum block transmission, as known from the literature, are obtained.


High Resolution, High Sensitivity Imaging Of The Galactic Center At 330 Mhz, Michael E. Nord, Crystal L. Brogan, Scott D. Hyman, T. Joseph W. Lazio, Namir E. Kassim, Ted N. Larosa, K. Anantharamaiah, Nebojsa Duric Sep 2003

High Resolution, High Sensitivity Imaging Of The Galactic Center At 330 Mhz, Michael E. Nord, Crystal L. Brogan, Scott D. Hyman, T. Joseph W. Lazio, Namir E. Kassim, Ted N. Larosa, K. Anantharamaiah, Nebojsa Duric

Faculty Articles

We present results derived from a wide field, sub-arcminute resolution VLA image of the Galactic Center region at 330 MHz (λ = 90 cm). With a resolution of ∼7″ × 12″ and an rms noise of 1.6 mJy beam−1, this image represents a significant increase in resolution and sensitivity over the previously published VLA image at this frequency (eg. LaRosa et al. 2000). The improvement in sensitivity has significantly increased the census of small diameter sources in the region, resulted in the detection of two new Non-Thermal Filaments (NTFs) and 18 new NTF candidates, and resulted in …


A Full-Wave Investigation Of The Use Of A 'Cancellation Factor' In Gw-Airglow Interaction Studies, Yonghui Yu Sep 2003

A Full-Wave Investigation Of The Use Of A 'Cancellation Factor' In Gw-Airglow Interaction Studies, Yonghui Yu

Master's Theses - Daytona Beach

Atmospheric gravity waves (GWs) perturb minor species involved in the chemical reactions of airglow emissions in the mesopause region of the earth's atmosphere. The so-called 'Cancellation Factor' (CF) is defined as a transfer function relating the amplitude of airglow brightness fluctuation to the amplitude of GW-induced fluctuation in temperature [Swenson and Gardner, 1998]. This transfer factor can be used to determine GW fluxes and the forcing effects of GWs on the mean state through airglow observations, because GW fluxes are proportional to the square of GW amplitude.

Numerical models [Walterscheid et al., 1987; Schubert et al., 1991] have previously shown …


Rescattering Of Ultralow-Energy Electrons For Single Ionization Of Ne In The Tunneling Regime, Robert Moshammer, Joachim Hermann Ullrich, Bernold Feuerstein, Daniel Fischer, Alexander Dorn, Claus Dieter Schroter, Jose R. Crespo Lopez-Urrutia, C. Hoehr, Horst Rottke, Christoph Trump, M. Wittmann, Georg Korn, Wolfgang Sandner Sep 2003

Rescattering Of Ultralow-Energy Electrons For Single Ionization Of Ne In The Tunneling Regime, Robert Moshammer, Joachim Hermann Ullrich, Bernold Feuerstein, Daniel Fischer, Alexander Dorn, Claus Dieter Schroter, Jose R. Crespo Lopez-Urrutia, C. Hoehr, Horst Rottke, Christoph Trump, M. Wittmann, Georg Korn, Wolfgang Sandner

Physics Faculty Research & Creative Works

Electron emission for single ionization of Ne by 25 fs, 1.0 PW/cm2 laser pulses at 800 nm was investigated. Kinematics was studied using a 'reaction microscope'. Results showed a zero longitudinal momentum of a low-energy electron with high resolution.


Two-Loop Bethe-Logarithm Correction In Hydrogenlike Atoms, Krzysztof Pachucki, Ulrich D. Jentschura Sep 2003

Two-Loop Bethe-Logarithm Correction In Hydrogenlike Atoms, Krzysztof Pachucki, Ulrich D. Jentschura

Physics Faculty Research & Creative Works

We calculate the two-loop Bethe logarithm correction to atomic energy levels in hydrogenlike systems. The two-loop Bethe logarithm is a low-energy quantum electrodynamic (QED) effect involving multiple summations over virtual excited atomic states. Although much smaller in absolute magnitude than the well-known one-loop Bethe logarithm, the two-loop analog is quite significant when compared to the current experimental accuracy of the 1 S – 2 S transition: It contributes - 8.19 and - 0.84 k H z for the 1 S and the 2 S state, respectively. The two-loop Bethe logarithm has been the largest unknown correction to the hydrogen Lamb …


The Prairie Naturalist Volume 35, No.3 September 2003 Sep 2003

The Prairie Naturalist Volume 35, No.3 September 2003

The Prairie Naturalist

BROWN-HEADED COWBIRDS IN GRASSLANDS: THEIR HABITATS, HOSTS, AND RESPONSE TO MANAGEMENT ▪ J. A. Shaffer, C. M. Goldade, M. F. Dinkins, D. H. Johnson, L. D. Igl, and B. R. Euliss

LlGUMIA SUBROSTRATA (BIVALVIA: UNIONIDAE) IN MINNESOTA AND ITS STATUS IN THE UPPER MIDWEST ▪ B. E. Sietman, D. E. Kelner, R. A. Hart, and M. Davis

GUIDELINES FOR FINDING NESTS OF PASSERINE BIRDS IN TALLGRASS PRAIRIE ▪ M. Winter, S. E. Hawks, J. A. Shaffer, and D. H. Johnson

RESPONSE OF THE LEAST SHREW TO PREY OLFACTORY CUES ▪ F. Punzo and C. Gonzalez

Book Reviews

North Dakota's Butterflies …


Book Review: Observer's Guide To Stellar Evolution: The Birth, Life, And Death Of Stars, T. D. Oswalt Sep 2003

Book Review: Observer's Guide To Stellar Evolution: The Birth, Life, And Death Of Stars, T. D. Oswalt

Publications

This document is Dr. Oswalt’s review of Observer's Guide to Stellar Evolution : the Birth, Life, and Death of Stars by Mike Inglis. Springer, 2003 236p, 1-85233-465-7 $44.95


Blackbird And Starling Strikes To Civil Aircraft In The United States, 1990-2001, Scott C. Barras, Sandra E. Wright, Thomas E. Seamans Sep 2003

Blackbird And Starling Strikes To Civil Aircraft In The United States, 1990-2001, Scott C. Barras, Sandra E. Wright, Thomas E. Seamans

United States Department of Agriculture Wildlife Services: Staff Publications

Bird-aircraft collisions (bird strikes) pose hazards to aircraft and cost civil aviation hundreds of millions of dollars in repairs and logistical expenses annually in the United States. Blackbirds and starlings (Sturnus vulgaris) in particular have caused some of the most devastating aircraft accidents related to bird strikes in the United States and Europe. To determine the impacts of blackbirds and starlings to aviation in the United State, we searched the Federal Aviation Administration’s (FAA) National Wildlife Strike Database for all reported strikes involving these species. During 1990-2001, 1,704 strikes involving blackbirds and starlings were reported to the FAA …


Context-Aware Semantic Association Ranking, Boanerges Aleman-Meza, Christian Halaschek-Wiener, I. Budak Arpinar, Amit P. Sheth Sep 2003

Context-Aware Semantic Association Ranking, Boanerges Aleman-Meza, Christian Halaschek-Wiener, I. Budak Arpinar, Amit P. Sheth

Kno.e.sis Publications

Discovering complex and meaningful relationships, which we call Semantic Associations, is an important challenge. Just as ranking of documents is a critical component of today's search engines, ranking of relationships will be essential in tomorrow's semantic search engines that would support discovery and mining of the Semantic Web. Building upon our recent work on specifying types of Semantic Associations in RDF graphs, which are possible to create through semantic metadata extraction and annotation, we discuss a framework where ranking techniques can be used to identify more interesting and more relevant Semantic Associations. Our techniques utilize alternative ways of specifying the …


One-Layer Neural-Network Controller With Preprocessed Inputs For Autonomous Underwater Vehicles, Sarangapani Jagannathan, Gustavo Galan Sep 2003

One-Layer Neural-Network Controller With Preprocessed Inputs For Autonomous Underwater Vehicles, Sarangapani Jagannathan, Gustavo Galan

Electrical and Computer Engineering Faculty Research & Creative Works

Navigating, guiding, and controlling autonomous underwater vehicles (AUVs) are challenging and difficult tasks compared to the autonomous surface-level operations. Controlling the motion of such vehicles require the estimation of unknown hydrodynamic forces and moments and disturbances acting on these vehicles in the underwater environment. in this paper, a one-layer neural-network (NN) controller with preprocessed input signals is designed to control the vehicle track along a desired trajectory, which is specified in terms of desired position and attitude. in the absence of unknown disturbances and modeling errors, it is shown that the tracking error system is asymptotically stable. in the presence …


Modeling And Control Of Vinyl Chloride In Drinking Water Distribution Systems, Michael Beardsley, Craig D. Adams Sep 2003

Modeling And Control Of Vinyl Chloride In Drinking Water Distribution Systems, Michael Beardsley, Craig D. Adams

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

In water distribution systems containing PVC pipe manufactured in the "early era" (prior to 1977), vinyl chloride can leach into drinking water resulting in vinyl chloride concentrations exceeding the 2 μg·L-1 maximum contaminant level. Field testing of dead-end segments of water distribution systems consisting of early-era PVC pipe was conducted to examine their initial intrapipe vinyl chloride monomer (VCM) concentrations based on a Fickian-diffusion-Based leaching model. the experiments showed a wide range of VCM concentrations within early-era PVC pipe ranging from less than 50 to more than 600 mg·kg-1. based on the diffusion modeling approach, a protocol was designed that …


Continuity Of Semantic Operators In Logic Programming And Their Approximation By Artificial Neural Networks, Pascal Hitzler, Anthony K. Seda Sep 2003

Continuity Of Semantic Operators In Logic Programming And Their Approximation By Artificial Neural Networks, Pascal Hitzler, Anthony K. Seda

Computer Science and Engineering Faculty Publications

One approach to integrating first-order logic programming and neural network systems employs the approximation of semantic operators by feedforward networks. For this purpose, it is necessary to view these semantic operators as continuous functions on the reals. This can be accomplished by endowing the space of all interpretations of a logic program with topologies obtained from suitable embeddings. We will present such topologies which arise naturally out of the theory of logic programming, discuss continuity issues of several well-known semantic operators, and derive some results concerning the approximation of these operators by feedforward neural networks.


Illinois River 2002 Pollutant Loads At Arkansas Highway 59 Bridge, Marc A. Nelson, Wade Cash Sep 2003

Illinois River 2002 Pollutant Loads At Arkansas Highway 59 Bridge, Marc A. Nelson, Wade Cash

Technical Reports

Automatic water samplers and a U. S. Geological Survey gauging station were established in 1995 on the main stem of the Illinois River at the Arkansas Highway 59 Bridge. Since that time, continuous stage and discharge measurements and water quality sampling have been used to determine pollutant concentrations and loads in the Arkansas portion of the Illinois River. This report represents the results from the measurement and sampling by the Arkansas Water Resources Center -Water Quality Lab for January 1, 2002 to December 31, 2002.


The Galactic Center Nonthermal Filaments: Recent Observations And Theory, Ted La Rosa, Michael E. Nord, T. Joseph W. Lazio, Steven N. Shore, Namir E. Kassim Sep 2003

The Galactic Center Nonthermal Filaments: Recent Observations And Theory, Ted La Rosa, Michael E. Nord, T. Joseph W. Lazio, Steven N. Shore, Namir E. Kassim

Faculty Articles

The large-scale topology and strength of the Galactic Center magnetic field have been inferred from radio imaging of the nonthermal filaments (NTFs). These objects, which seem to be unique to the Galactic center, are defined by extreme aspect ratios and a high degree of polarization. Recent high resolution, wide-field VLA imaging of the GC at 90 cm has revealed new candidate NTFs with a wide range of orientations relative to the Galactic plane. We present follow up 6 cm polarization observations of 6 of these candidates and confirm 4 as new NTFs. Together the new 90 and 6 cm results …


The Role Of Research In Expanded Regional Management Of Double-Crested Cormorants, Scott C. Barras, Mark E. Tobin Sep 2003

The Role Of Research In Expanded Regional Management Of Double-Crested Cormorants, Scott C. Barras, Mark E. Tobin

United States Department of Agriculture Wildlife Services: Staff Publications

The number of double-crested cormorants (Phalacrocorax auritus) breeding in the Great Lakes states and provinces has increased during recent decades. Their abundance and foraging habits have thrust this species into conflict with the aquaculture industry and fisheries interests. The U. S. Fish and Wildlife Service proposed a change in the management of double-crested cormorants recently to alleviate these conflicts, especially with aquaculture, natural resources, and federal fish hatcheries. Research activities should be an integral component of these expanded efforts to manage cormorants, including further investigations on cormorant impacts to the aquaculture industry and evaluations of the added benefits …


Csrees School Of Natural Resources Comprehensive Five-Year Review Sep 2003

Csrees School Of Natural Resources Comprehensive Five-Year Review

School of Natural Resources: Documents and Reviews

No abstract provided.


The Radiopacity Of 29 Resin Restorative Materials Compared To Enamel, Peter Lubisich Iv Sep 2003

The Radiopacity Of 29 Resin Restorative Materials Compared To Enamel, Peter Lubisich Iv

Loma Linda University Electronic Theses, Dissertations & Projects

The radiodensity of a composite resin can greatly influence a clinician's ability to analyze a restoration for failure. The purpose of this study was to determine the relative radiopacities of 29 resin restorative materials compared to enamel, and to verify the comparable radiopacity between shades of 23 of the restorative composite resin materials. Composite resin discs measuring >5mm in diameter and 2 mm in thickness were made and polymerized. Radiographs were taken of the composite resin discs, which included an aluminum step wedge for calibration and a densitometer was used to measure the radiodensity of the composite resin samples. The …


0415-0935_Opt_Lris, Adam J. Burgasser Sep 2003

0415-0935_Opt_Lris, Adam J. Burgasser

Publications and Research

No abstract provided.


The Status Of Women In The Geosciences, Mary Anne Holmes, Connie Frey, Suzanne O'Connell, Lois K. Ongley Sep 2003

The Status Of Women In The Geosciences, Mary Anne Holmes, Connie Frey, Suzanne O'Connell, Lois K. Ongley

Department of Earth and Atmospheric Sciences: Faculty Publications

Most geoscientists agree that gender equity is a worthy goal for our field, but there is disagreement as to how to measure gender equity and what it actually means. Will the geosciences achieve gender equity when the proportion of women on our faculty and in professional positions accurately reflects the proportion in our undergraduate classes? Or is gender equity 50 percent of all positions in all fields, including undergraduate enrollment? By any of these measures, we are not yet there. Women earned 40 percent of the undergraduate degrees in geoscience (geology, oceanography, atmospheric sciences, geophysics) in 2001, and 38 percent …


Quantification Of Bone Deposition In Onlay Bone Grafting, Gregory Alan Kammeyer Sep 2003

Quantification Of Bone Deposition In Onlay Bone Grafting, Gregory Alan Kammeyer

Loma Linda University Electronic Theses, Dissertations & Projects

The purpose of this study was to quantitatively evaluate; 1) mandibular posterior mono-cortical block onlay bone graft success rates 2) the amount of grafted bone retained after initial resorption in radiographic projections. Seven consecutive patients with 14 mandibular posterior implant sites requiring bone augmentation for implants of a standard 3.8mm x 10mm dimension were sought. Mono-cortical block bone grafts from the ipsilateral ascending ramus were placed then observed with two standardized CT scans, dividing them into two groups: Group A had the first CT at 4 weeks after graft placement and a second taken before Prosthodontic reconstruction, 36.7 weeks later. …


Afci Quarterly Input – Unlv July Through September, 2003, Harry Reid Center For Environmental Studies. Nuclear Science And Technology Division Sep 2003

Afci Quarterly Input – Unlv July Through September, 2003, Harry Reid Center For Environmental Studies. Nuclear Science And Technology Division

Transmutation Research Program Reports (TRP)

Quarterly report highlighting research projects and objectives of the Transmutation Research Program at the Nuclear Science & Technology Division, Harry Reid Research Center.

The University of Nevada, Las Vegas supports the AFCI through research and development of technologies for economic and environmentally sound refinement of spent nuclear fuel. The UNLV program has four components: infrastructure, international collaboration, student-based research, and management and program support.


Blackwood Catchment : Beaufort Zone (Zone 4) : Catchment Appraisal 2002, Henry Brockman, Blackwood Rapid Catchment Appraisal Team (Wa ), Natural Heritage Trust (Australia) Sep 2003

Blackwood Catchment : Beaufort Zone (Zone 4) : Catchment Appraisal 2002, Henry Brockman, Blackwood Rapid Catchment Appraisal Team (Wa ), Natural Heritage Trust (Australia)

Resource management technical reports

Using the Rapid Catchment Appraisal process, this report summarises current information for the Beaufort zone, located in the mid to southern part of the Blackwood basin, including parts of the shires of Kojonup, West Arthur, Woodanilling, Katanning, Broomehill, Wagin and Boyup Brook, Western Australia. Assesses the condition of, and future risks to agricultural and natural resources, provides information for reducing those risks and identifies the most suitable options to manage the risk.


0937+2931_Opt_Lris, Adam J. Burgasser Sep 2003

0937+2931_Opt_Lris, Adam J. Burgasser

Publications and Research

No abstract provided.


Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 20, Number 1, September 2003, College Of Engineering And Computer Science, Wright State University Sep 2003

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 20, Number 1, September 2003, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

An eight page newsletter created by the Wright State University College of Engineering and Computer Science that addresses the current affairs of the college.


Target Sets: A Tool For Understanding And Predicting The Behavior Of Interacting Q-Learners, Nancy Fulda, Dan A. Ventura Sep 2003

Target Sets: A Tool For Understanding And Predicting The Behavior Of Interacting Q-Learners, Nancy Fulda, Dan A. Ventura

Faculty Publications

Reinforcement learning agents that interact in a common environment frequently affect each others’ perceived transition and reward distributions. This can result in convergence of the agents to a sub-optimal equilibrium or even to a solution that is not an equilibrium at all. Several modifications to the Q-learning algorithm have been proposed which enable agents to converge to optimal equilibria under specified conditions. This paper presents the concept of target sets as an aid to understanding why these modifications have been successful and as a tool to assist in the development of new modifications which are applicable in a wider range …


Design Of Antiresonant-Reflecting Optical Waveguide-Type Vertical-Coupled Surface-Emitting Lasers Using Transfer Matrix Method, Chyng Wen Tee, C. C. Tan, S. F. Yu Sep 2003

Design Of Antiresonant-Reflecting Optical Waveguide-Type Vertical-Coupled Surface-Emitting Lasers Using Transfer Matrix Method, Chyng Wen Tee, C. C. Tan, S. F. Yu

Research Collection Lee Kong Chian School Of Business

A simple transfer matrix method is proposed to calculate the radiation losses of a cylindrical antiresonant-reflecting optical waveguide (ARROW). It is found that the planar approximation underestimates the radiation losses but overestimates the design tolerance of the ARROW-type vertical-cavity surface-emitting lasers (VCSELs). An iteration technique, which is incorporated with the transfer matrix method, is also developed to design ARROW-type VCSELs for minimum radiation losses in a more effective manner.


Kinetic And Analytical Studies On Catalytic And Noncatalytic Oxidative Degradation Of Some Hazardous Organic Dyes Using Hydrogen Peroxide, Salem Hmoud Salem Al-Ameri Sep 2003

Kinetic And Analytical Studies On Catalytic And Noncatalytic Oxidative Degradation Of Some Hazardous Organic Dyes Using Hydrogen Peroxide, Salem Hmoud Salem Al-Ameri

Theses

Dyes have become a very important part to countless modem applications. As a result of this huge consumption of dyes in manufacturing processes, huge amounts of wastewater contaminated with dyes are released into different natural dumps like rivers and seas. These dyes contaminated wastes have dangerous impacts on the environment and toxic affects. Two problems are facing scientists concerned about this environmental task. First, dyes vary in their chemical and physical natures and different waste treatments are needed which sometime are not available. Second, getting rid of these pollutants from its sources is costly, that many manufactures can not afford. …


Supernova Reverse Shocks: Sic Growth And Isotopic Composition, Ethan A-N. Deneault, Donald D. Clayton, Alexander Heger Sep 2003

Supernova Reverse Shocks: Sic Growth And Isotopic Composition, Ethan A-N. Deneault, Donald D. Clayton, Alexander Heger

Publications

We present new mechanisms by which the isotopic compositions of X-type grains of presolar SiC are altered by reverse shocks in Type II supernovae. We address three epochs of reverse shocks: pressure wave from the H envelope near t ¼ 106 s, reverse shock from the presupernova wind near 108–109 s, and reverse shock from the interstellar medium near 1010 s. Using one-dimensional hydrodynamics we show that the first creates a dense shell of Si and C atoms near 106 s in which the SiC surely condenses. The second reverse shock causes precondensed grains to move rapidly forward through decelerated …