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n1vux (1492)

n1vux
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Only started with Perl4 and Perl5 in 1995. I was doing AWK etc for 12 years before that, and resisted switching. I've been doing OO since before C++ hit bigtime, with Objective-C and SmallTalk, so I really like the (no longer new) Perl5 OO style; and the Lispish Map style is also an old friend. What do I hack with Perl? All data that passes my way; systems monitoring scripts at $DayJob, weather data at night, and I cheat on NPR word puzzles. Member: Boston.pm.org [pm.org] BLU.org [blu.org] /. LinkedIn [linkedin.com]

N1VUX is my FCC-issued ham radio callsign.

Journal of n1vux (1492)

Wednesday April 27, 2005
02:29 PM

Science News -- Math today

[ #24408 ]
Pi seems a good random number generator - but not always the best

«If you wanted a random number, historically you could do worse than to pick a sequence from the string of digits in pi. But Purdue University scientists now say other sources might be better.
  Physicists including Purdue's Ephraim Fischbach have completed a study comparing the "randomness" in pi to that produced by 30 software random number generators and one chaos-generating physical machine. After conducting several tests, they have found that while sequences of digits from pi are indeed an acceptable source of randomness – often an important factor in data encryption and in solving certain physics problems – pi's digit string does not always produce randomness as effectively as manufactured generators do.»

- Pi, the naturally random number, may not be the best source of randomness, and may or may not be cost-efficient, but it's better quality than many intentional artificial attempts.
- Purdue, via EurekAlert ;
Earlier work via MAA index of Science News and LBL.GOV, 2

Navigating Celestial Currents - Interplanetary super-highways
« Mathematicians are creating an atlas of solar system highways along which spacecraft can coast using no fuel.»
- And I thought Traveller's jump lines were bogus. Well I was wrong. (Traveller is revived at SJG-Gurps.)
- Src, via MAA index of Science News and Manifolds in the Genesis mission - previous article at MAA
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  • I came into computers from a liberal arts background so my math-fu is very weak but isn't something random or not random? How can you have gradations of randomness?

    Maybe I should just FTFL or some such slashdot acronym.

    • Gradations of randomness are quite meaningful. The degree of randomness is how accurately you can guess what value is coming next. A two-headed coin is non-random, since you know it always comes up heads. A regular coin potentially provides one bit of randomness, since it can come up either heads or tails, and you don't know which. But, it the coin is lopsided it could have a greater tendency to come up on one side than the other, say 50.1% heads and 49.9% tails. That is no longer absolutely random, bu
  • this posting was cited in a scholarly journal. http://interstat.statjournals.net/YEAR/2006/articles/0601001.pdf [statjournals.net]

    --
    Bill
    # I had a sig when sigs were cool
    use Sig;