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Displaying 51851 - 51875 of 73892

Information Technology: The Sixth Text Retrieval Conference (TREC-6)

August 1, 1998
Author(s)
Ellen M. Voorhees, Donna K. Harman
This paper provides an overview of the Sixth Text REtrieval Conference (TREC-6) held in Gaithersburg, Maryland, November 19-21, 1997. TREC-6 is the latest in a series of workshops designed to foster research in text retrieval. The paper describes the tasks

Low-Temperature Elastic Constants of Polycrystalline Indium

August 1, 1998
Author(s)
Sudook A. Kim, H M. Ledbetter
Using an ultrasonic pulse-echo method, we measured the elastic constants of polycrystalline indium from 300 K to 5K. All elastic constants showed regular temperature behavior as predicted by an Einstein-oscillator model. The shear and Young moduli showed

Matching Pursuit Filters Applied to Face Identification

August 1, 1998
Author(s)
P J. Phillips
We present a face identification algorithm that automatically processes an unknown image by locating and identifying the face. The heart of the algorithm is the use of pursuits filters. A matching pursuit filter is an adapted wavelet expansion, where the

NIST Atomic and Molecular Databases on the World Wide Web

August 1, 1998
Author(s)
Robert A. Dragoset, Peter J. Mohr, Karen J. Olsen, Edward B. Saloman, G G. Wiersma, D Zucker
The Physics Laboratory of the National Institute of Standards and Technology is using the world wide web to disseminate the physical reference data it has been producing and/or evaluating. Web databases have been developed, each with an interface specially

NIST Atomic Spectra Database (1998)

August 1, 1998
Author(s)
Yuri Ralchenko
We put Version 1 of this database online as an interactive Web server in 1995. Our first version has data on atomic energy levels for some 500 spectra, transition probability data for spectra of the iron-group elements, and wavelength data for spectra of a

Obstacle Detection and Mapping System

August 1, 1998
Author(s)
H Tsai-Hong, Steven Legowik, M Nashman
This paper discusses and evaluates an obstacle detection algorithm developed at NIST in support of the DEMO III Unmanned Ground Vehicle (UGV) program. The algorithm is a hybrid of grid-based and sensor-based obstacle detection and mapping techniques and is

On the Validity of the Poisson Hypothesis for Low-Level Counting; Investigation of the Distributional Characteristics of Background Radiation with the NIST Individual Pulse Counting System

August 1, 1998
Author(s)
George A. Klouda, Lloyd A. Currie, E M. Eijgenhuijsen
Does radioactive decay follow the Poisson distribution?--a fundamental question to which the theoretical answer seems to be, Yes. On the practical side, the answer to this question impacts the best achievable precision in well-controlled counting

Plane Wave Integral Representation for Fields in Reverberation Chambers

August 1, 1998
Author(s)
David A. Hill
A plane wave integral representation is presented for well-stirred fields in a reverberation chamber. The representation automatically satisfies Maxwell's equations in a source-free region and the statistical properties of the fields are introduced through

Reflection Measurement Problems Arising from Haze

August 1, 1998
Author(s)
George R. Jones Jr., Edward F. Kelley
Irreproducibility in some reflection measurement methods arises from the observance of the haze component of reflection (non-regular-specular, non-Lambertian). Because of the haze component, the measured reflection is sensitive to the apparatus

Scanning Height for ANSI C63.5 Calibrations

August 1, 1998
Author(s)
Kenneth H. Cavcey, Dennis G. Camell
The configuration of antennas at an Open Area Test site (OATS) for calibrations results in constructive and destructive electric fields. Regardless of the calibration method used, the antenna to be calibrated should be loacted where the field varies slowly

Size Changes and Interpenetration Within Concentrated Dendrimer Solutions

August 1, 1998
Author(s)
T J. Prosa, Barry J. Bauer, A Topp, Eric J. Amis, R L. Scherrenberg
The field of dendrimer research has grown dramatically in recent years with the synthesis of new materials quickly outpacing the characterization of simple material properties.[1] The lack of dendrimers in sufficient quantities has inhibited the ability to

Size Dependent Electronic Level Structure of InAs Nanocrystal Quantum Dots: Test of Multiband Effective Mass Theory

August 1, 1998
Author(s)
U Banin, J C. Lee, A A. Guzelian, A V. Kadavanich, A P. Alivastos, Garnett W. Bryant, A L. Efros, M Rose, W Jaskolski
The size dependence of the electronic spectrum of InAs nanocrystals ranging in radius from 10 to 35 Angstrom} has been studied by size-selective spectroscopy. An eight-band effective mass theory of the quantum size levels has been developed which describes
Displaying 51851 - 51875 of 73892
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