Another property of neurons is that they tend to compress or auto adjust, so when a consistent input is seen, the output will at first be quite active, and decay to a baseline as it becomes less sensitive to the current non fluctuating input. This has the effect of making what sounded very loud at first, not as loud later. In the case of vision, putting on rose colored glasses, gives the viewer a very pink color shifted image, but after an hour, the white point has been adjusted so the redness goes almost unnoticed.
This is generally a really good thing, otherwise our attention would constantly be pulled from one thing to another by regularly occurring inputs that don't really need the full focus of our attention, such as feeling the cloths we wear or the reverberations of sound inside a room. I think this property would be good to implement at least at the encoder level, but perhaps throughout the CLA. An obvious issue with this to me is that given a consistent stimuli to a sensor for a long period of time it would at first generate an SDR that looks different than what is generate later on, possibly making the input unrecognized. The benefit, I believe, is it would then be focusing on the faster changing input, which is probably more important for the CLA to generate meaningful and useful predictions. Patrick On Aug 2, 2013, at 5:00 PM, Scott Purdy wrote: > I had promised this a long time ago but here is a version of an adaptive > encoder that isn't quite as brittle as the current adaptive encoder: > > https://github.com/numenta/nupic/pull/155 > > It is loosely based on the idea of arithmetic coding and adapts to arbitrary > value ranges, while typically not changing representations by more than a bit > when a new value comes in. The main downside is that it requires a moving > window of values seen and the size of this is arbitrary. When I tested it I > did not find that it worked very well. Obviously if you can fix the > encodings like the regular scalar encoder then you don't have to worry about > losing learning when the representations adapt. But here it is in case you > are curious. > _______________________________________________ nupic mailing list [email protected] http://lists.numenta.org/mailman/listinfo/nupic_lists.numenta.org
