The Hangout is full it seems, so I’ll have to stick to the YouTube feed.
Thanks for doing this! Pete On 12 Nov 2013, at 23:53, Matthew Taylor <[email protected]> wrote: > Hangout: https://plus.google.com/hangouts/_/7ecpjh57bqs47e27f1hqkkcdps > YouTube: http://youtu.be/rSpYyUN4iP0 > --------- > Matt Taylor > OS Community Flag-Bearer > Numenta > > > On Sat, Nov 9, 2013 at 5:21 PM, Matthew Taylor <[email protected]> wrote: >> At this office hour[1], Subutai is going to lead us through the "CLA >> Quiz". We'll focus on the spatial pooler. The questions are below. >> Bring your brains! >> >> **Spatial Pooler / SDR Questions** >> >> 0) Is an untrained CLA spatial pooler just a “random hash” (random >> mapping from input to output vector)? Why or why not? What happens to >> the output of the spatial pooler if you randomly change one bit in the >> input. >> >> 1) Can you do spatial pooling with small numbers? For example, is it >> reasonable to have an SP with 20 columns? If not, why are large >> numbers important in SDR's? >> >> a) What's the difference between picking "5 columns out of 50" vs "50 >> out of 500"? Both have 10% sparsity. >> >> b) What's the difference between picking "50 out of 100" vs "50 out of >> 1000"? Both will output 50 1's. >> >> 2) Suppose the input vector (input to the SP) is 10,000 bits long, >> with 5% sparsity. What is the right value of coincInputPoolPct? How do >> you figure this out? >> >> 3) How does the SDR representation of input A in isolation, and input >> B in isolation, compare with the SDR representation of input A >> overlapped with B? Alternatively, how does the representation of a >> horizontal line and the representation of a vertical line compare with >> the representation of a cross? >> >> 4) Suppose we have an input vector that is 10,000 bits long. Suppose >> the spatial pooler has 500 columns, of which 50 are active at any >> time. >> >> a) Can we distinguish many patterns, or a small number? Which >> patterns are likely to be confused? >> >> b) What happens to the SDR representation if we add noise to the >> patterns? >> >> c) What happens if we add occlusions? >> >> 5) What are disadvantages of SDR's? >> >> 6) How does online learning happen in the SP? >> >> --------- >> Matt Taylor >> OS Community Flag-Bearer >> Numenta >> >> [1] >> https://plus.google.com/b/100642636108337517466/events/crmrf6k58s77hlgk4v30bll8hp8 > > _______________________________________________ > nupic mailing list > [email protected] > http://lists.numenta.org/mailman/listinfo/nupic_lists.numenta.org _______________________________________________ nupic mailing list [email protected] http://lists.numenta.org/mailman/listinfo/nupic_lists.numenta.org
