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Displaying 29276 - 29300 of 73829

Diversity Performance of a Practical Non-Coherent Detect-and-Forward Receiver

November 30, 2008
Author(s)
Michael R. Souryal, Huiqing You
We propose a non-coherent receiver for the fixed detect-and-forward relay channel and derive a closed-form tight upper bound on its bit error probability in Rayleigh fading channels. Using this upper bound, we show that the receiver achieves nearly full

Non-Coherent Amplify-and-Forward Generalized Likelihood Ratio Test Receiver

November 30, 2008
Author(s)
Michael R. Souryal
This paper proposes a simple non-coherent amplify-and-forward receiver for the relay channel and evaluates its diversity performance for Rayleigh fading channels. We use the generalized likelihood ratio test to obtain the decision rule in closed form

Security Challenges in Seamless Mobility - How to ``Handover'' the Keys?

November 30, 2008
Author(s)
Katrin Hoeper, Lidong Chen, Antonio Izquierdo Manzanares, Nada T. Golmie
In this paper, we discuss key management challenges for seamless handovers across heterogeneous wireless networks. We focus on fast access authentication protocols that allow expedited network entry by utilizing existing keying material from previous

Computational Parameters in Simulation of Microscope Images

November 28, 2008
Author(s)
Egon Marx, James E. Potzick
The simulation of microscope images computed from scattered fields determined using integral equations depend on a number of parameters that are not related to the scatterer or to the microscope but are choices made for the computation method. The effect

Integral Equations for 3-D Scattering: Finite Strip on a Substrate

November 28, 2008
Author(s)
Egon Marx
Singular integral equations that determine the exact fields scattered by a dielectric or conducting finite strip on a substrate are presented. The computation of the image of such a scatterer from these fields by Fourier optics methods is also shown.

Managing Materials Information in the Supply Chain

November 28, 2008
Author(s)
John V. Messina, Eric D. Simmon
One important aspect of sustainable manufacturing is the acquisition and management of product material information. This information may be used to improve the design and manufacturing process, facilitate recycling, and to help comply with regulations

Neutron Transmission of Single-Crystal Magnesium Fluoride

November 27, 2008
Author(s)
John Barker, David F. Mildner, Jose Rodriguez Rivera, P. Thiyagarajan
The neutron attenuation through single-crystal magnesium fluoride has been measured as a function of wavelength at both room temperature and 77 K. These data confirm a total cross section that is lower than MgO for wavelengths greater than 0.2 nm. MgF 2

Addressing Y-Chromosome Short Tandem Repeat(Y-STR) Allele Nomenclature

November 25, 2008
Author(s)
John M. Butler, Margaret C. Kline, Amy E. Decker
Currently 120 different Y-chromosome short tandem repeat (Y-STR) markers are used by various genetic genealogy testing laboratories. In some cases, different laboratories may designate the same Y-STR allele with two different nomenclatures making data

Measuring intensity correlations with a two-element superconducting nanowire single-photon detector

November 24, 2008
Author(s)
Eric Dauler, Martin Stevens, Burm Baek, Richard J. Molnar, Scott A. Hamilton, Richard Mirin, Sae Woo Nam, Karl Berggren
Second-order intensity correlation measurements were made using a two-element superconducting nanowire single photon detector (SNSPD) without the need for an optical beam splitter. This approach can be used to obtain a 50-ps full width at half maximum

Pressure-induced volume-collapsed tetragonal phase of CaFe 2 As 2 as seen via neutron scattering

November 24, 2008
Author(s)
A. Kreyssig, Mark Green, Y. Lee, G. D. Samolyuk, Pawel Zajdel, Jeffrey Lynn, S. L. Bud'ko, M. S. Torikachvili, N. Ni, S. Nandi, Juscelino Leao, Sarah Poulton, D. N. Argyriou, B. N. Harmon, R. J. McQueeny, P. C. Canfield, A. I. Goldman
Recent investigations of the superconducting iron-arsenide families have highlighted the role of pressure, be it chemical or mechanical, in fostering superconductivity. Here we report that CaFe2As2 undergoes a pressure-induced transition to a nonmagnetic

Designing artificial cells to harness the biological ion gradient

November 23, 2008
Author(s)
Jian Xu, David A. LaVan
Cell membranes contain numerous natural nanoscale conductors, i.e. ion channels and ion pumps1-4, that work in concert to form transmembrane or transcellular ion gradients that can be triggered to release an action potential (AP)1, 5. Can artificial cells

Yb Optical Lattice Clock

November 23, 2008
Author(s)
Nathan D. Lemke, Andrew Ludlow, Zeb Barber, N Poli, C.W. Hoyt, Long-Sheng Ma, Jason Stalnaker, Christopher W. Oates, Leo Hollberg, James C. Bergquist, A. Brusch, Tara Fortier, Scott Diddams, Thomas P. Heavner, Steven R. Jefferts, Tom Parker
We describe the development and latest results of an optical lattice clock based on neutral Yb atoms, including investigations based on both even and odd isotopes. We report a fractional frequency uncertainty below 10 -15 for 171Yb.

Josephson phase qubit circuit for the evaluation of advanced tunnel barrier materials

November 21, 2008
Author(s)
Jeffrey S. Kline, Haohua Wang, Seongshik Oh, John M. Martinis, David P. Pappas
We have found that crystalline Josephson junctions have critical current density control problems which decrease circuit yield. We present a qubit circuit designed to accommodate a factor-of-five variation in critical current density for the evaluation of

Terahertz spectroscopy of aqueous L-Proline in reverse micelles

November 21, 2008
Author(s)
Catherine C. Cooksey, Edwin J. Heilweil, Benjamin Greer
A new method for obtaining room temperature terahertz (THz) absorption spectra of aqueous-phase biomolecules in the frequency range 1 THz to 21 THz (35 cm-1 to 700 cm-1) is reported. The spectrum for L-Proline was acquired by solvating the amino acid

A Recommendation for the Use of PIV Credentials in Physical Access Control Systems (PACS)

November 20, 2008
Author(s)
William I. MacGregor, Ketan L. Mehta, David A. Cooper, Karen A. Scarfone
This document provides best practice guidelines for integrating the PIV Card with the physical access control systems (PACS) that authenticate the cardholders in Federal facilities. Specifically, this document recommends a risk-based approach for selecting

Bluetooth Security: Protecting Wireless Networks and Devices

November 20, 2008
Author(s)
Shirley M. Radack
This bulletin summarizes information disseminated in NIST Special Publication (SP) 800-121, Guide to Bluetooth Security: Recommendations of the National Institute of Standards and Technology, which was written by Karen Scarfone of NIST and by John Padgette

Controlled Transport of Magnetic Particles Using Soft Magnetic Patterns

November 20, 2008
Author(s)
Richard Conroy, Gary Zabow, John M. Moreland, Alan P. Koretsky
Inspired by magnetic bubble memory technology, we demonstrate the temporal and spatial manipulation of superparamagnetic beads guided by soft magnetic patterns in a rotating magnetic field. Soft magnetic structures allow complex and repetitive tasks to be

Final Report on the Collapse of World Trade Center Building 7, Federal Building and Fire Safety Investigation of the World Trade Center Disaster (NIST NCSTAR 1A)

November 20, 2008
Author(s)
Sivaraj Shyam-Sunder, Richard G. Gann, William L. Grosshandler, Hai S. Lew, Richard W. Bukowski, Fahim Sadek, Frank W. Gayle, John L. Gross, Therese P. McAllister, Jason D. Averill, James R. Lawson, Harold E. Nelson, Stephen A. Cauffman
This report describes how the fires that followed the impact of debris from the collapse of WTC 1 (the north tower) led to the collapse of WTC 7; an evaluation of the building evacuation and emergency response procedures; what procedures and practices were

Global Structural Analysis of the Response of World Trade Center Building 7 to Fires and Debris Impact Damage, Federal Building and Fire Safety Investigation of the World Trade Center Disaster (NIST NCSTAR 1-9A)

November 20, 2008
Author(s)
Robert S. MacNeill, Therese P. McAllister
This report analyzes the global response of WTC 7 to fire-induced structural failures and the resulting sequence of component and subsystem failures to determine the events that led to the global collapse of the building. The analysis involved a finite

Pair correlation functions of simple solutes in a Lennard-Jones solvent

November 20, 2008
Author(s)
Yehuda A. Ben Naim, Vincent K. Shen
We have calculated the pair correlation functions for several binary mixtures composed of simple solutes in a Lennard-Jones solvent. In particular, we have studied the solute-solute pair correlation functions and their dependence on the total density, the

Structural Fire Response and Probable Collapse Sequence of World Trade Center Building 7, Federal Building and Fire Safety Investigation of the World Trade Center Disaster (NIST NCSTAR 1-9) VOLUMES 1 and 2

November 20, 2008
Author(s)
Therese P. McAllister
This report provides technical documentation of how NIST reconstructed the effects of the events on September 11, 2001 on WTC 7. This includes how the fires that followed the impact of debris from the collapse of WTC 1 (the north tower) led to the collapse
Displaying 29276 - 29300 of 73829
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