Friday, December 5, 2008

More AC experiments

I'm starting to have fun exploring the possibilities of this AC simulator. Above are spatially stable patterns using a bi-stable latch and small random initial conditions (approximating the noisy conditions of uninitialized amps). In the first picture, there is no diffusion so each parcel of space commits to one of the two states randomly. In the second picture, with diffusion, larger areas that by chance share a state tend to recruit their neighbors into that state. But, all of this recruitment must happen early because the gain on the latches eventually wins at which point there's no changing anyone's state (like an election). Thus, by dialing the ratio of diffusion to latch gain, you can choose the mean size of the features which is a cool phenotype all by itself. For example, imagine that this was a self-organized filter -- that one parameter could allow the construction of different kinds of mechanical particle filters.

In this picture I've stated to combine features. The left and center are two independent ring-oscillators with noisy initial conditions which create these interesting patterns as I've shown previously. (Although I'm still not positive they aren't artifacts, I'm starting to get a theory about how they form, and I'm going to be testing those ideas with controlled experiments tomorrow.) On the right is product of the two in oscillators which results in interesting spatio-temporal patterns. Like the latches above, these patterns are uncontrollable in all but gross properties because the pattern's position is the result of what amounts to "fossilized noise". In other words, the asymmetries at t=0 are amplified/converted into patterns at later time. That said, the form of the patterns is inspirational -- it hints at what is possible in potentially more information-rich initial conditions. For example, I now have an inkling how to partition space into integer sub-divisions (like fingers on a hand) without explicitly putting them there -- I'll be trying that soon.

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