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Digital
Video
And
the Emmy Goes to ... a NIST ATP Partner!
Sarnoff
Corp. recently received an Emmy Award from the National Academy
of Television Arts and Sciences for “outstanding achievement
in technological advancement” for a unique technology to
predict how viewers will perceive the quality of digitally processed
TV images or still pictures. Sarnoff organized a NIST
Advanced Technology Program project to develop a commercially
practical version of the technology, which models the human visual
system.
In the process of being edited, encoded, transmitted and displayed,
digital video images are mathematically compressed, decompressed
and modified. Researchers wondered if the changes made a perceptible
difference to the viewer, and if so, how much? Because human vision
is complex, it’s a difficult question for a computer to answer.
Sarnoff researchers had developed a model that accurately predicted
what viewers would register as a “just noticeable difference,”
but the model was large and unwieldy. As part of a 1995 ATP project,
Sarnoff led a team to refine and optimize the model so that it
could be embodied on a single-chip processor to provide accurate,
real-time analysis of image quality.
Instrument maker Tektronix uses the Sarnoff technology, called
JNDmetrix™, in a new picture-quality analyzer, and Sarnoff
has released a software version for personal computers. The technology
can evaluate the performance of new video compression systems
for digital broadcasts or the Internet, and gives buyers and sellers
of video compression technology an independent measure of system
quality.
Read more about the ATP online at www.atp.nist.gov.
Details of the Sarnoff JNDmetrix™ technology can be found
at www.sarnoff.com/sarnoff_story/press/2000/100400.htm.
Media
Contact:
Michael
Baum, (301) 975-2763
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Information Technology
Debut
Set for Complex Computing ‘All for One’ Standard
Scientists
and engineers who have to make extremely complex calculations
favor a computing approach known as parallel processing. Parallel
processing is a way to break up a computing problem into pieces
that various processors—the “brains” inside computers—can
work on simultaneously. It produces extraordinary results, allowing
people to make calculations in a week that previously would have
taken a year.
While parallel processing has been around for years, many scientists
have been frustrated in their efforts to use it. It is easy to
create a parallel processing computer network if the computers
were all made by the same company. Yet harnessing the combined
computing power of machines made by different manufacturers has
been much more difficult. A new voluntary standard, the Interoperable
Message Passing Interface, eliminates many of those problems.
The first public demonstrations of the IMPI will take place at
the Supercomputing 2000 conference in Dallas on Nov. 4-10, 2000.
Participating with independent exhibits of the IMPI in action
will be Hewlett-Packard Co., the University of Notre Dame and
MPI Software Technology Inc.
Computer scientists at NIST have coordinated work on the new standard.
NIST teamed up with some of the world’s largest computer
hardware and software manufacturers to develop the IMPI. NIST
also has created a web-based conformance tester for IMPI.
More information about the standard is available online at http://impi.nist.gov/IMPI/.
The web site for the conference may be found at www.sc2000.org/.
Media
Contact:
Philip
Bulman, (301) 975-5661
Building
Research
Cool
Site Yields Hot Data on Heat Transmission
For
what purpose would NIST researchers use a one-meter-diameter hot
plate? If you guessed, “to heat up a mighty big pot of coffee,”
you’re wrong. However, data derived from this device and
previous hot plates have helped make the daily life of Americans
more comfortable for nearly 80 years.
For example, heat transmission values gained from calculating
the thermal conductivity properties of materials measured in hot
plates have enabled industry to build more efficient heating,
refrigeration and air-conditioning systems as well as improving
wall insulation properties. NIST-tabulated values for heat transmission
properties of common building and insulating materials also have
contributed to the development of modern building technology standards.
Now, researchers in two NIST groups—the Building
and Fire Research Laboratory and the Standard
Reference Data Program—have compiled the test data for
steady-state heat transmission measurements in an Internet database.
This database currently contains all of the evaluated thermal
conductivity measurements produced by NIST from 1932 to 1983 using
a 200-millimeter guarded hot plate apparatus. The data were previously
unavailable because they were reported only to an individual sponsor
or researcher, or simply recorded in handwritten test logs. Additional
data from other NIST heat transmission experiments will be added
in the future.
The new web site contains more than 2,100 records of thermal conductivity
data for a variety of thermal insulation materials such as cellular
plastics, corkboard and glass fiber, as well as building materials
such as fiberboard and light-weight concrete.
The NIST Standard Reference Database 81 on Heat Transmission Properties
of Insulating and Building Materials may be accessed at http://srdata.nist.gov/insulation.
For historical background on the guarded hot-plate apparatus,
go to www.bfrl.nist.gov/863/hotplate/.
Media
Contact:
John
Blair, (301) 975-4261
Thermophysics
Refined
Procedures Improve Refrigeration Properties Research
Damage
to the Earth’s ozone layer caused by use of chlorofluorocarbons
has prompted an international effort to measure and correlate
the thermophysical properties of alternative refrigerant fluids
such as hydrochloro-fluorocarbons and hydrofluorocarbons. Scientists
around the world who compared their measurement results discovered
wide discrepancies. For one property, viscosity, data differed
by as much as 15 to 30 percent between laboratories.
The situation led the International Union of Pure and Applied
Chemistry to conduct a tightly managed round-robin measurement
study organized by NIST to attempt to reduce the uncertainties.
For this study, samples from a carefully prepared, high-purity
source of a refrigerant known as 1,1,1,2-tetrafluoroethane, or
R134a, were distributed to the nine participating labs in meticulously
cleaned containers. Each lab made measurements following procedures
that maintained the sample’s purity and allowed sample recovery
for subsequent analysis.
When these procedures were followed, measurement discrepancies
were reduced dramatically. For example, the largest discrepancy
for viscosity was 6 percent using a variety of measurement techniques.
The NIST Physical and Chemical Properties Division not only contributed
measurements as a round-robin member but also analyzed the data
deviations among all of the laboratories for IUPAC.
The study proved that sample purity must be maintained throughout
the measurement process, and even the sample container and measurement
apparatus must be regarded as a source of contamination. NIST
is now working with IUPAC on the development of improved standard
reference correlations based on the study data to enable the design
of more efficient and compact refrigeration equipment.
For more information, contact Richard
A. Perkins, NIST, MC 838.07, Boulder, Colo. 80305-3328; (303)
497-5499.
Media
Contact:
Fred
McGehan (Boulder), (303) 497-3246
Time
& Frequency
Atomic
Clock Among Popular Science’s ‘Best of What’s New’
The
editors of Popular Science reviewed thousands of recent
products and technology developments before selecting 100 of them
for inclusion in their 13th annual “Best of What’s New”
list in the December 2000 issue. One of the awards goes to the
most recent in NIST’s 51-year-long line of ever-more-precise
atomic clocks, the NIST-F1 cesium fountain clock, unveiled in
December 1999.
NIST-F1, the nation’s primary standard of frequency and time,
was built at the Boulder Laboratories by the agency’s Time
and Frequency Division. Operating with an uncertainty of less
than 2 parts in a quadrillion (corresponding to neither gaining
nor losing one second in nearly 20 million years), NIST-F1 is
among the most accurate standards of measurement ever constructed.
It is used to evaluate and enhance the performance of the other
clocks in NIST’s timekeeping system; its extreme accuracy
also is incorporated into the time signals broadcast by NIST’s
radio stations and other time services.
For more information on NIST F-1, go online to www.nist.gov/fountainclock.
Media
Contact:
Collier
Smith (Boulder),
(303) 497-3198
Physics
Egyptian
Professor Is NIST’s First SESAME Seed
Galila
Mehena, associate professor of physics at Cairo University in
Egypt, is spending one year as a SESAME Seed trainee at NIST’s
Synchrotron Ultraviolet Research Facility. SESAME (Synchrotron-light
for Experimental Science and Applications in the Middle East)
will be the first international research center in the Middle
East. An United Nations project, SESAME will be located in Jordan.
Mehena, who will work at NIST until the summer of 2001, will use
her time here to learn the basics of synchrotron radiation. Synchrotron
radiation is the light produced by electrons racing at nearly
the speed of light around a donut-shaped ring in a strong magnetic
field. To the naked eye, synchrotron radiation looks like the
bright blue flame of a welder’s torch, but it is much richer
in content. The spectrum of its light contains every imaginable
shade of color, extending all the way from radio waves to X-rays.
Scientists use this light to probe and measure a wide variety
of materials.
The German government has agreed to donate a working synchrotron
to the SESAME project. The U.S. Department of Energy has committed
funds to train Middle Eastern scientists at US synchrotron radiation
facilities. NIST and DoE are supporting the cost of Mehena’s
training.
For more details on SESAME, see http://www.sesame.org.jo.
Media
Contact:
Michael
Baum,
(301) 975-2763
Thermodynamics
‘Full
of Hot Air’ Takes on New Meaning at NIST
Atmospheric
air is a mixture of fluids including nitrogen, oxygen, argon,
carbon dioxide, water vapor and other trace elements. That’s
more than most of us need to know, but for others—including
researchers and staff at liquefaction companies, manufacturing
firms, laboratories and wind tunnels—it isn’t nearly
enough.
That’s where a collaboration between NIST and the University
of Idaho has made the difference. The partners measured and developed
an equation of state for the thermodynamic properties of natural
air, along with mixtures of nitrogen, argon and oxygen. The standard
air measured and correlated by NIST and the UI is dry and contains
no carbon dioxide or trace elements. The thermodynamic property
formulation is valid for liquid, vapor and supercritical air at
temperatures from 59.75 to 2,000 kelvin at pressures up to 2,000
megapascals.
The model is published in the current issue of the Journal
of Physical and Chemical Reference Data (Vol. 29, No. 3),
a joint venture of NIST and the American Institute of Physics.
For a copy of the journal article, go online to http://ojps.aip.org/jpcrd/.
Media
Contact:
Fred
McGehan (Boulder),
(303) 497-3246
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