Hello - I hope this is not being posted to the wrong list. This is my first post here. Please let me know if there is a more appropriate place for this question.
In preparation for learning NuPIC, I have read "On Intelligence", and I am now reading the HTM white paper put out by Numenta. Making my way through the white paper, I got stuck on one passage, which I can't really make sense of. Wondering if anyone can help me through this part. The passage in question is on pages 11-12 of the white paper PDF - specifically the second paragraph included below. *HTM regions also use sparse distributed representations. In fact, the memory mechanisms within an HTM region are dependent on using sparse distributed representations, and wouldn’t work otherwise. The input to an HTM region is always a distributed representation, but it may not be sparse, so the first thing an HTM region does is to convert its input into a sparse distributed representation.* *For example, a region might receive 20,000 input bits. The percentage of input bits that are “1” and “0” might vary significantly over time. One time there might be 5,000 “1” bits and another time there might be 9,000 “1” bits. The HTM region could convert this input into an internal representation of 10,000 bits of which 2%, or 200, are active at once, regardless of how many of the input bits are “1”. As the input to the HTM region varies over time, the internal representation also will change, but there always will be about 200 bits out of 10,000 active. * So, what exactly is going on here? How does a fluctuating input flow of 20,000 bits get converted into 200 bits? Obviously there is something important going on here, but I don't understand what it is. Any help illuminating this would be greatly appreciated! Many thanks, Jeff
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