Saturday, December 17, 2005

Day 228

Came across another sport where men and women compete equally, and this one isn't even particularly for rich people: sheep-dog trials. Yep, it looks like "One Man and his Dog" is back.

Somehow, it's marvellously soothing to watch; it's like a visual version of that old traditional classic, the shipping forecast on Radio 4. Mike and I were actually discussing whether there might be a market for a CD of shipping forecasts: you could get a couple of hundred of them onto a CD, then set it to shuffle play.

Which does slightly remind of something I heard about some years ago. Apparently, it used to be possible to get hold of a mag tape full of random data. Random data is very useful, for generating tests and performing statistical analyses, but most of the time people just use pseudo-random data generated by the computer itself. This has gone spectacularly wrong on occasion, so having true random data available is useful.

So how do you get real random data? Well, in this case by monitoring output of radioactive decay; in a particular time period, if an odd number of particles are detected, then a 1 is added to the data, if it's even then a 0 is added. There was also apparently a slight statistical tweak, to allow for the fact that zero is an even number (because the distribution of the numbers of particles produced is obviously cut off at zero: there's no way, even in quantum mechanics, to emit -1 particles).

1 comment:

Henri-V said...

Nice post. I always learn new things when drop by.