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2004

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Articles 4411 - 4440 of 4447

Full-Text Articles in Physical Sciences and Mathematics

Inverse Eigenproblems And Associated Approximation Problems For Matrices With Generalized Symmetry Or Skew Symmetry, William F. Trench Dec 2003

Inverse Eigenproblems And Associated Approximation Problems For Matrices With Generalized Symmetry Or Skew Symmetry, William F. Trench

William F. Trench

No abstract provided.

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Non-Contact Measurement Of Nerve Displacement During Action Potential With A Dual-Beam Low Coherence Interferometer, Christopher Fang-Yen, M Chu, H S. Seung, R R. Dasari, M S. Feld Dec 2003

Non-Contact Measurement Of Nerve Displacement During Action Potential With A Dual-Beam Low Coherence Interferometer, Christopher Fang-Yen, M Chu, H S. Seung, R R. Dasari, M S. Feld

Christopher Fang-Yen

No abstract provided.

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Learning To Decode Cognitive States From Brain Images, Tom M. Mitchell, Rebecca Hutchinson, Radu S. Niculescu, Francisco Pereira, Xuerui Wang, Marcel Adam Just, Sharlene D. Newman Dec 2003

Learning To Decode Cognitive States From Brain Images, Tom M. Mitchell, Rebecca Hutchinson, Radu S. Niculescu, Francisco Pereira, Xuerui Wang, Marcel Adam Just, Sharlene D. Newman

Marcel Adam Just

No abstract provided.

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Holistic Word Recognition For Handwritten Historical Documents, Victor Lavrenko, Toni M. Rath, R. Manmatha Dec 2003

Holistic Word Recognition For Handwritten Historical Documents, Victor Lavrenko, Toni M. Rath, R. Manmatha

R. Manmatha

Most offline handwriting recognition approaches proceed by segmenting words into smaller pieces (usually characters) which are recognized separately. The recognition result of a word is then the composition of the individually recognized parts. Inspired by results in cognitive psychology, researchers have begun to focus on holistic word recognition approaches. Here we present a holistic word recognition approach for single-author historical documents, which is motivated by the fact that for severely degraded documents a segmentation of words into characters will produce very poor results. The quality of the original documents does not allow us to recognize them with high accuracy - …

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Before The Web There Was Gopher, Philip L. Frana Dec 2003

Before The Web There Was Gopher, Philip L. Frana

Philip L Frana

The World Wide Web, universally well known today, was preceded by an efficient software tool that was fondly named Gopher. The Internet Gopher, much like the Web, enabled users to obtain information quickly and easily. Why, then, did it disappear but the Web did not? Gopher faded into obscurity for two main reasons: hypertext and commerce.

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A Search Engine For Historical Manuscript Images, Toni M. Rath, R. Manmatha, Victor Lavrenko Dec 2003

A Search Engine For Historical Manuscript Images, Toni M. Rath, R. Manmatha, Victor Lavrenko

R. Manmatha

Many museum and library archives are digitizing their large collections of handwritten historical manuscripts to enable public access to them. These collections are only available in image formats and require expensive manual annotation work for access to them. Current handwriting recognizers have word error rates in excess of 50% and therefore cannot be used for such material. We describe two statistical models for retrieval in large collections of handwritten manuscripts given a text query. Both use a set of transcribed page images to learn a joint probability distribution between features computed from word images and their transcriptions. The models can …

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Toward A Climate Change Strategy For Pennsylvania, John C. Dernbach Dec 2003

Toward A Climate Change Strategy For Pennsylvania, John C. Dernbach

John C. Dernbach

No abstract provided.

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Extracting User Intent In Mixed Initiative Teleoperator Control, Andrew H. Fagg, Michael Rosenstein, Robert Platt Jr., Roderic Grupen Dec 2003

Extracting User Intent In Mixed Initiative Teleoperator Control, Andrew H. Fagg, Michael Rosenstein, Robert Platt Jr., Roderic Grupen

Roderic Grupen

User fatigue is common with robot teleoperation interfaces. Mixed initiative control approaches attempt to reduce this fatigue by allowing control responsibility to be shared between the user and an intelligent control system. A critical challenge is how the user can communicate her intentions to the control system in an intuitive manner as possible. In the context of control of a humanoid robot, we propose an interface that uses the movement currently commanded by the user to assess the intended outcome. Specifically, given the observation of the motion of the teleoperated robot for a given period of time, we would like …

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Lead In Residential Soil And Dust In A Mining And Smelting District In Northern Armenia: A Pilot Study, Varduhi Petrosyan, Anna Orlova, Charles E. Dunlap, Emil Babayan, Mark Farfel, Margrit Von Braun Dec 2003

Lead In Residential Soil And Dust In A Mining And Smelting District In Northern Armenia: A Pilot Study, Varduhi Petrosyan, Anna Orlova, Charles E. Dunlap, Emil Babayan, Mark Farfel, Margrit Von Braun

Charles Dunlap

This pilot study of sources of lead exposure in residential settings was conducted in a mining and smelting district in northern Armenia. Samples of exterior soil and dust and interior house dust were collected in and around apartment buildings in Alaverdi where the country’s largest polymetallic smelter is located, and in nearby mining towns of Aghtala and Shamlugh. The NITON XL- 723 Multi-Element XRF analyzer was used for lead testing. Lead levels in samples from Alaverdi were higher than those in Shamlugh and Aghtala. In all three towns, the highest lead levels were found in loose exterior dust samples, and …

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H2s (22,0-21,1) Observations Toward The Sgr B2 Region, Young C. Minh, William M. Irvine, S J. Kim Dec 2003

H2s (22,0-21,1) Observations Toward The Sgr B2 Region, Young C. Minh, William M. Irvine, S J. Kim

William M. Irvine

The H2S 22,0-21,1 line emission is observed to be strongly localized toward Sgr B2(M), and emissions from other positions in the more extended SgrB2 region are almost negligible. H2S is thought to form effectively by the passage of the C-type shocks but to be quickly transformed to SO2 or other sulfur species (Pineau des Forêts et al. 1993). Such a shock may have enhanced the H2S abundance in Sgr B2(M), where massive star formation is taking place. But the negligible emission of H2S from other observed positions may indicate that these positions have not been affected by shocks enough to …

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Hermitian, Hermitian R-Symmetric, And Hermitian R-Skew Symmetric Procrustes Problems, William F. Trench Dec 2003

Hermitian, Hermitian R-Symmetric, And Hermitian R-Skew Symmetric Procrustes Problems, William F. Trench

William F. Trench

No abstract provided.

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Consumption Function, Douglas G. Steigerwald Dec 2003

Consumption Function, Douglas G. Steigerwald

Douglas G. Steigerwald

No abstract provided.

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Minimization Problems For (R,S)-Symmetric And (R,S)-Skew Symmetric Matrices, William F. Trench Dec 2003

Minimization Problems For (R,S)-Symmetric And (R,S)-Skew Symmetric Matrices, William F. Trench

William F. Trench

No abstract provided.

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Introduction, Symposium Facing Climate Change: Opportunity And Tool For States, John C. Dernbach Dec 2003

Introduction, Symposium Facing Climate Change: Opportunity And Tool For States, John C. Dernbach

John C. Dernbach

No abstract provided.

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Simplification And Strengthening Of Weyl's Definition Of Asymptotic Equal Distribution Of Two Families Of Finite Sets, William F. Trench Dec 2003

Simplification And Strengthening Of Weyl's Definition Of Asymptotic Equal Distribution Of Two Families Of Finite Sets, William F. Trench

William F. Trench

No abstract provided.

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Analyzing Time-To-Event Data In A Clinical Trial When An Unknown Proportion Of Subjects Has Experienced The Event At Entry, Raji Balasubramanian, Stephen W. Lagakos Dec 2003

Analyzing Time-To-Event Data In A Clinical Trial When An Unknown Proportion Of Subjects Has Experienced The Event At Entry, Raji Balasubramanian, Stephen W. Lagakos

Raji Balasubramanian

In some clinical trials, where the outcome is the time until development of a silent event, an unknown proportion of subjects who have already experienced the event will be unknowingly enrolled due to the imperfect nature of the diagnostic tests used to screen potential subjects.F or example, commonly used diagnostic tests for evaluating HIV infection status in infants, such as DNA PCR and HIV Culture, have low sensitivity when given soon after infection.This can lead to the inclusion of an unknown proportion of HIV-infected infants into clinical trials aimed at the prevention of transmission from HIV-positive mothers to their infants …

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An Elementary Note On Asymptotic Properties Of Toeplitz And Multilevel Toeplitz Matrices, William F. Trench Dec 2003

An Elementary Note On Asymptotic Properties Of Toeplitz And Multilevel Toeplitz Matrices, William F. Trench

William F. Trench

No abstract provided.

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Characterization And Properties Of Matrices With Generalized Symmetry Or Skew Symmetry, William F. Trench Dec 2003

Characterization And Properties Of Matrices With Generalized Symmetry Or Skew Symmetry, William F. Trench

William F. Trench

No abstract provided.

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Science And Engineering Of Nanoparticle-Polymer Composites: Insights From Computer Simulation, Francis W. Starr, Sharon C. Glotzer Dec 2003

Science And Engineering Of Nanoparticle-Polymer Composites: Insights From Computer Simulation, Francis W. Starr, Sharon C. Glotzer

Francis Starr

No abstract provided.

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On Multivariate Abel-Gontscharoff Interpolation, Tian-Xiao He Dec 2003

On Multivariate Abel-Gontscharoff Interpolation, Tian-Xiao He

Tian-Xiao He

By using Gould's annihilation coefficients, we obtain an explicit fundamental polynomials of Multivariate Abel-Gontscharoff Interpolation and its remainder expression.

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Sadc Challenges Country Water Partnerships To Make Impact, Stanley Mubako Dec 2003

Sadc Challenges Country Water Partnerships To Make Impact, Stanley Mubako

Stanley Mubako

No abstract provided.

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Environment-Friendly Organic Synthesis Using Bismuth Compounds. Bismuth Triflate Catalyzed Synthesis Of Substituted 3,4-Dihydro-2h-L-Benzopyrans, Ram S. Mohan, Mai P. Nguyen, Joshua N. Arnold, Katherine E. Peterson Dec 2003

Environment-Friendly Organic Synthesis Using Bismuth Compounds. Bismuth Triflate Catalyzed Synthesis Of Substituted 3,4-Dihydro-2h-L-Benzopyrans, Ram S. Mohan, Mai P. Nguyen, Joshua N. Arnold, Katherine E. Peterson

Ram S. Mohan

A highly catalytic method for the synthesis of dihydrobenzopyrans from salicylaldehydes has been developed. An extension of this method to the synthesis of a pyrano [2,3,b]benzopyran has also been achieved. Bi(OTf)3.xH2O (1< x < 4) (0.1mol%) smoothly catalyzes the condensation of substituted salicylaldehydes with 2,2-dimethoxypropane to give the corresponding substituted 3,4-dihydro-2H-1-benzopyrans as a mixture of diastereomers (9:1) in moderate yields. The relative configuration of the methoxy groups in the two diastereomers was established by NOE experiments. The advantages of this method include the use of an easy to handle, inexpensive and relatively non-toxic catalyst.

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Bismuth Compounds In Organic Synthesis. Bismuth Nitrate Catalyzed Chemoselective Synthesis Of Acylals From Aromatic Aldehydes, Ram S. Mohan, David H. Aggen, Joshua N. Arnold, Patrick D. Hayes, Nathaniel J. Smoter Dec 2003

Bismuth Compounds In Organic Synthesis. Bismuth Nitrate Catalyzed Chemoselective Synthesis Of Acylals From Aromatic Aldehydes, Ram S. Mohan, David H. Aggen, Joshua N. Arnold, Patrick D. Hayes, Nathaniel J. Smoter

Ram S. Mohan

1Aromatic aldehydes are smoothly converted into the corresponding acylals in good yields in the presence of 3–10 mol% Bi(NO3)3•5H2O. Ketones are not affected under the reaction conditions. The relatively non-toxic nature of the catalyst, its ease of handling, easy availability and low cost make this procedure especially attractive for large-scale synthesis.

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Cortical Activation And Synchronization During Sentence Comprehension In High-Functioning Autism: Evidence Of Underconnectivity, Marcel Adam Just, Vladimir L. Cherkassky, Timothy A. Keller, Nancy J. Minshew Dec 2003

Cortical Activation And Synchronization During Sentence Comprehension In High-Functioning Autism: Evidence Of Underconnectivity, Marcel Adam Just, Vladimir L. Cherkassky, Timothy A. Keller, Nancy J. Minshew

Marcel Adam Just

No abstract provided.

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Spectral Densities Of Embedded Interfaces In Composite Materials, A. R. Mcgurn, Anthony Roy Day, D. J. Bergman, L. C. Davis, M. F. Thorpe Dec 2003

Spectral Densities Of Embedded Interfaces In Composite Materials, A. R. Mcgurn, Anthony Roy Day, D. J. Bergman, L. C. Davis, M. F. Thorpe

Anthony Roy Day

The effective resistivity and conductivity of two media that meet at a randomly rough interface are computed in the quasistatic limit. The results are presented in the spectral density representations of the Bergman-Milton formulation for the properties of two-component composite materials. The spectral densities are extracted from computer simulations of resistor networks in which the random interface separates two regions containing different types of resistors. In the limit that the bond lengths in the resistor network are small compared to parameters characterizing the surface roughness, the resistor network simulation approximates the continuum limit of the two-component composite. The Bergman-Milton formulation …

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Dynamic Heterogeneities In Supercooled Water, Nicolas Giovambattista, Marco Mazza, Sergey V. Buldyrev, Francis W. Starr, H. Eugene Stanley Dec 2003

Dynamic Heterogeneities In Supercooled Water, Nicolas Giovambattista, Marco Mazza, Sergey V. Buldyrev, Francis W. Starr, H. Eugene Stanley

Francis Starr

No abstract provided.

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Existence Of Solutions To A Hamiltonian System Without Convexity Condition On The Nonlinearity, Gregory S. Spradlin Dec 2003

Existence Of Solutions To A Hamiltonian System Without Convexity Condition On The Nonlinearity, Gregory S. Spradlin

Gregory S. Spradlin

We study a Hamiltonian system that has a superquadratic potential and is asymptotic to an autonomous system. In particular, we show the existence of a nontrivial solution homoclinic to zero. Many results of this type rely on a convexity condition on the nonlinearity, which makes the problem resemble in some sense the special case of homogeneous (power) nonlinearity. This paper replaces that condition with a different condition, which is automatically satisfied when the autonomous system is radially symmetric. Our proof employs variational and mountain-pass arguments. In some similar results requiring the convexity condition, solutions inhabit a submanifold homeomorphic to the …

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Swarm-Mediated Cluster-Based Construction, S. Kazadi, J. Wigglesworth, A. Grosz, A. Lim, D. Vitullo Dec 2003

Swarm-Mediated Cluster-Based Construction, S. Kazadi, J. Wigglesworth, A. Grosz, A. Lim, D. Vitullo

Sanza Kazadi

We investigate the use of swarm clustering algorithms in the design of simple robots capable of carrying out swarm-mediated construction. Methods for generating multiple clusters of predetermined size are developed. Relative cluster motion algorithms are also developed and explored. All robotic algorithms are predicated on the use of only robots utilizing no processing, gps, or explicit communication. Simple stigmergic communication and minimal sensing capabilities are used exclusively. We demonstrate swarms of minimal agents building equilateral triangles, squares, and pentagons. Future use of these methods in the design of more sophisticated construction techniques is discussed.

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Modelling Dynamic Conditional Correlations In Wti Oil Forward And Futures Returns, Alessandro Lanza, Matteo Manera, Micheal Mcaleer Dec 2003

Modelling Dynamic Conditional Correlations In Wti Oil Forward And Futures Returns, Alessandro Lanza, Matteo Manera, Micheal Mcaleer

Matteo Manera

This paper estimates the dynamic conditional correlations in the returns on WTI oil onemonth forward prices, and one-, three-, six-, and twelve-month futures prices, using recently developed multivariate conditional volatility models. The dynamic correlations enable a determination of whether the forward and various futures returns are substitutes or complements, which are crucial for deciding whether or not to hedge against unforeseen circumstances. The models are estimated using daily data on WTI oil forward and futures prices, and their associated returns, from 3 January 1985 to 16 January 2004. At the univariate level, the estimates are statistically significant, with the occasional …

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Using Dynamic Information In The Supply Network, Jeffrey Barker Dec 2003

Using Dynamic Information In The Supply Network, Jeffrey Barker

Jeffrey Barker

No abstract provided.

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