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January 31, 2006

Four Things

This meme seems not to want to lie down and die, so, given it now has some credibility after Anil posted it, I caved in.

Four jobs I've had

Four films I can watch over and over again

Four places I've lived
(Actually, I can only think of 3)

Four TV shows I love

Four highly regarded and recommended TV shows I've never seen more than a few minutes of

Four places I've visited

Four of my favourite dishes

Four sites I visit daily

Four places I would rather be right now
I'll ignore the fact it's nearly 1am, shall I?

Four more bloggers I'm tagging, even though I know some of them won't do it

Posted by James at 00:57 | Comments (2)
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January 17, 2006

Consider a spherical cow, covered in resistors

(Anybody who didn't take an A-level in Physics may as well switch off now. Any readers who sat next to me throughout A-level Physics lessons may wish to consider that it might be their fault I wasn't paying enough attention to be able to work this out. ;-) )

This question's been bugging me for days. I did have an answer, but after a spot of googling showed me I was wrong, I realised I was talking rubbish.

Imagine, if you will, a flat square grid of points, such that every point is connected to the 4 adjacent points by a 1Ω resistor. The grid extends infinitely in all directions. What is the resistance between 2 points on the grid a knight's move apart? (e.g. 2 squares up and 1 across, WLOG) Or, for a simpler starter question, what about between 2 points diagonally adjacent? Or even just 2 adjacent points? (Is that as simple as just 1Ω? My hunch is no.)

Maybe I've missed something while googling for answers to this, but if anyone has a good solution I'd be very interested to hear it! Just to clarify, I have some numerical answers from googling, but I'm far more interested in how they're arrived at than what the actual numbers are.

[Update: Chris has considerably better google-fu than me, and found a solution for the diagonal case. It contains hard maths that I can't really justify spending the time to get my head around in the middle of exam season, alas. There's a paper with even more on this too. Eek!]

Posted by James at 22:59 | Comments (0)
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January 03, 2006

Contactability

Oops. The mail server which handles my main email account, which also happens to provide DNS for jimbo.org.uk, died a little before 2pm today. I should be able to bring it back on Friday some time, but until then, anyone wanting to contact me should try my gmail address, jimbo.green @ gmail.com, or something more old fashioned like the telephone.

My vague understanding of DNS suggests that this site should remain reachable, because there are secondary DNS servers available, but there might be delays if you try to contact the dead one first. Sorry about that!

[Update: everything seems to be back online.]

Posted by James at 20:33 | Comments (0)
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January 01, 2006

The next big thing

Javascript looks like continuing to be the big in thing this year, so I vaguely hope to add 3 neato features to various websites I run in the coming months.

  1. Lightbox for image display on OGN. (via Toby)
  2. SIFR for rendering titles on this blog, and maybe elsewhere. (via Chris)
  3. Finally, OGN should also be getting Google Maps integration, which looks like Oxford's, just as soon as the next version of OpenGuides gets released.

But enough asinine crap for now.

Posted by James at 16:34 | Comments (3)
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