Comments on: Birds on a wire and the Ising model http://blog.eqnets.com/2009/11/30/birds-on-a-wire-and-the-ising-model/ Science, networks, and security Tue, 20 Dec 2011 18:48:34 +0000 hourly 1 http://wordpress.com/ By: Hosting Anak Bangsa http://blog.eqnets.com/2009/11/30/birds-on-a-wire-and-the-ising-model/#comment-239 Sun, 07 Nov 2010 21:01:48 +0000 http://blog.eqnets.com/?p=711#comment-239 Wow, Nice post you have, thanks

]]> By: RZ http://blog.eqnets.com/2009/11/30/birds-on-a-wire-and-the-ising-model/#comment-146 Sun, 06 Dec 2009 09:47:53 +0000 http://blog.eqnets.com/?p=711#comment-146 Cool, but that means that there isn’t any bird-bird interaction, so J=0 and no Ising, at least to zero’th approximation.

]]> By: eqnets http://blog.eqnets.com/2009/11/30/birds-on-a-wire-and-the-ising-model/#comment-144 Thu, 03 Dec 2009 16:23:23 +0000 http://blog.eqnets.com/?p=711#comment-144 Found this today:

http://answers.google.com/answers/threadview?id=442524

]]> By: RZ http://blog.eqnets.com/2009/11/30/birds-on-a-wire-and-the-ising-model/#comment-143 Tue, 01 Dec 2009 08:50:26 +0000 http://blog.eqnets.com/?p=711#comment-143 According to the link, the cows really do align themselves according to the external magnetic field. I guess they are para-magnetic (this is funnier in hebrew).

]]> By: eqnets http://blog.eqnets.com/2009/11/30/birds-on-a-wire-and-the-ising-model/#comment-141 Mon, 30 Nov 2009 13:57:31 +0000 http://blog.eqnets.com/?p=711#comment-141 The cow thing is covered here:

http://afp.google.com/article/ALeqM5j1FvUL7uj_NIAPrfLwSb0HMV4gnA

To me the interesting part would be determining the parameters of the model in terms of environmental influences

]]> By: RZ http://blog.eqnets.com/2009/11/30/birds-on-a-wire-and-the-ising-model/#comment-140 Mon, 30 Nov 2009 12:02:59 +0000 http://blog.eqnets.com/?p=711#comment-140 Wasn’t something similar done with cow orientations using google earth?

Anyway, as far as I can remember, the correlation function for 1-d Ising is exponential, which implies that for a given snapshot, the probability to see N sequential birds with the same orientation decays exponentially. It is difficult to separate this prediction from other simple models of bird orientation.

A real test is to compare to equilibrium dynamics ( if I had to guess, I’d say Glauber). An exploration of time dynamics of birds on a wire would be much more difficult, just consider modeling the case of a bird leaving or landing on the wire. Looks more like an adsorption problem to me- preferential attachment where birds already are perched + a “hard core” repulsion at close ranges.

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