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TBTF for 1995-06-03: Global positioning and hypertext pasta

Keith Dawson (dawson dot tbtf at gmail dot com)
Sat, 3 Jun 1995 06:27:05 -0400



>>From Edupage:


CIVILIAN USE OF GLOBAL POSITIONING SYSTEM
Using 24 Earth-orbiting satellites, the Global Positioning System was
originally designed to allow the military to tell troops, tanks or aircraft
their exact position, but the GPS now generates $2 billion a year in
commercial business. Two government studies (from the National Academy of
Public Administration and the National Research Council) recommend steps
that will turn that into a $30 billion business by 2005. But the studies
also urge that the system be kept under government management, to maintain
confidence in it and to ensure that the U.S. remains a world leader in the
technology. (New York Times 1995-06-01 A13)

[GPS sends two kinds of signals: (1) encoded signals, decipherable only by the
military, provide accurate positioning information (on the order of a meter);
and (2) clear signals that provide ~50-meter accuracy. The civilian-accessible
signals contain deliberate errors. The factor driving GPS commercial use is
the development of a "workaround." Ground stations, about the size of a re-
frigerator, know exactly where they are; they receive the civilian GPS signals
and resend them with the errors corrected. This system achieves *better* ac-
curacy than the military one, to within a few *inches* -- good enough to land
a jetliner automatically in whiteout fog. The FAA is testing this very con-
cept but has not yet certified it. Now, the President has the ability, in time
of war, to alter the error factors in the civilian signal or even to cut out
the signal entirely. If that happened today people would be $2 billion worth
of upset. Once every airliner's landing depends on civilian GPS that presiden-
tial option had better never get exercised. This is the best example I know of
commerce using, improving, and finally usurping a military technology. Oh, well,
of course there is the example of the Internet itself...]

UNRELIABLE E-MAIL
Forbes magazine recently conducted an experiment, sending 240 test messages
over the Internet to determine how reliable the system really is. The
results were less than encouraging: 9% properly addressed messages failed
to reach their destination, and many others took an unacceptably long time
(up to two days) to get there. "Although the Internet is growing
exponentially, the number of people able to run it properly is growing only
linearly," explains Tony Rutkowski, executive director of the Internet
Society. Forbes' final thought? "If it absolutely, positively has to get
there, send it by overnight mail." (Forbes 1995-06-05 p.162)

HYPERTEXT BOWLS OF SPAGHETTI
Howard Strauss of Princeton University thinks WWW content designers need to
relearn some old lessons of scholarship: "In the past we learned how to
use footnotes, tables of contents, and indexes effectively, but in our
electronic formats we seem to have forgotten all that. We use too many
hypertext links, use them where they make no sense, ignore the difference
between footnotes and tables of contents, build links to bizarre and
unexpected places, ignore standard ways of linking, and confuse, rather
than enlighten, with hypertext structures that make bowls of spaghetti seem
like models of good organization." (Edutech Report, May'95, p.1)


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______________________________________________________
Keith Dawson dawson dot tbtf at gmail dot com dawson@atria.com
Layer of ash separates morning and evening milk.