Live data from Hacker News

Resurgence of Neural Networks

tjake.github.com

11–20 of 62 posts

Re: Resurgence of Neural Networks

#11
First, it's Geoffrey, not Gregory Hinton.

Here's a very good tech talk from him about RBMs: http://www.youtube.com/watch?v=AyzOUbkUf3M

That said, both approaches loosely mirror the function of the brain, as neurons are not simple threshold devices, and both backpropagation and the RBMs training algorithms do not have a biophysical equivalent.

Re: Resurgence of Neural Networks

#12

Really interesting stuff. I had once attempted to build a genetic algorithm for manipulating the synapse weights, specifically because of the problems of traditional back-propagation falling into local minima (unfortunately, some serious shit at work made it drop by the wayside). This RBM approach sounds better than back-propagation, but it also sounds like it would be prone to runaway feedback. One of the performanc…

It sounds almost like you want to recreate a Connection Machine [0] using modern(ish) hardware.

0: http://en.wikipedia.org/wiki/Connection_Machine

Re: Resurgence of Neural Networks

#13
post #11

First, it's Geoffrey, not Gregory Hinton. Here's a very good tech talk from him about RBMs: http://www.youtube.com/watch?v=AyzOUbkUf3M That said, both approaches loosely mirror the function of the brain, as neurons are not simple threshold devices, and both backpropagation and the RBMs training algorithms do not have a biophysical equivalent.

Oh sorry. I fixed it. Sorry Geoffrey!

Re: Resurgence of Neural Networks

#14
As mentioned in this thread by nicholasjarnold, Jeff Hawkins work on HTM (detailed in his excellent book "On Intelligence") seems superficially similar to this. Has anyone had experience of both approaches. HTM seems to have much more structure in the network, but I know next to nothing about AI and would love to hear from those who know a bit more.

Re: Resurgence of Neural Networks

#15

Really interesting stuff. I had once attempted to build a genetic algorithm for manipulating the synapse weights, specifically because of the problems of traditional back-propagation falling into local minima (unfortunately, some serious shit at work made it drop by the wayside). This RBM approach sounds better than back-propagation, but it also sounds like it would be prone to runaway feedback. One of the performanc…

The problem with stuff like this is 16Mhz * 100 is far less than 3500Mhz * 4. So doing this in software on the desktop is generally a much better idea let alone 750Mhz * 1000+ if you can get a good GPU implementation. You also hit significant speed of light and bandwidth issues if you want to network a lot of these together because neurons don't just talk to there 4 closest friends.

PS: Still a fun project, just harder than you might think to scale.

Re: Resurgence of Neural Networks

#16

Really interesting stuff. I had once attempted to build a genetic algorithm for manipulating the synapse weights, specifically because of the problems of traditional back-propagation falling into local minima (unfortunately, some serious shit at work made it drop by the wayside). This RBM approach sounds better than back-propagation, but it also sounds like it would be prone to runaway feedback. One of the performanc…

I had once attempted to build a genetic algorithm for manipulating the synapse weights, specifically because of the problems of traditional back-propagation falling into local minima (unfortunately, some serious shit at work made it drop by the wayside).

There are many ways to avoid this, for example have a look at:

http://en.wikipedia.org/wiki/Rprop http://en.wikipedia.org/wiki/Conjugate_gradient_method

In traditional (I am not talking about the "deep" stuff) neural networks optimization is hardly ever the problem though, most often under- or over- fitting is the issue that produces poor performance.

One of the performance problems with neural networks is that the number of cores on a typical machine are far less than the number of input and intermediate nodes in the network.

This sounds odd. Certainly doing neural networks in hardware is interesting, but it sounds a bit like an imagined problem, I mean, when multiplying 20 numbers one does not complain that the number of cores is less than 20. And most often it is the training of the network that is resource-intensive not the actual running of it.

Re: Resurgence of Neural Networks

#17

Really interesting stuff. I had once attempted to build a genetic algorithm for manipulating the synapse weights, specifically because of the problems of traditional back-propagation falling into local minima (unfortunately, some serious shit at work made it drop by the wayside). This RBM approach sounds better than back-propagation, but it also sounds like it would be prone to runaway feedback. One of the performanc…

You may want this: http://www.greenarraychips.com/index.html

Re: Resurgence of Neural Networks

#18
post #9

If you're really interested in understanding more about he "hierarchy of filters" quote, and much more related to that theory of how our brains operate, I strongly suggest the book On Intelligence by Jeff Hawkins. Super interesting stuff!

Here's a page that gives a high level overview of the technology that he has helped to develop: https://www.numenta.com/technology.html On Intelligence has dramatically changed the way I think about thinking. It's an awesome book.

Thanks for this, I forgot to mention about Numenta. Your comment prompted me to search my old archives for the setup file to "Vitamin D Video", a motion and object detection program that was a very early example of Numenta technology being successfully implemented.

Now, it looks like those Vitamin D people have their own company: http://www.vitamindinc.com/

Even the really early versions of Vitamin D were impressive. Anybody use it for anything interesting now?

Re: Resurgence of Neural Networks

#19
post #7

If you're really interested in understanding more about he "hierarchy of filters" quote, and much more related to that theory of how our brains operate, I strongly suggest the book On Intelligence by Jeff Hawkins. Super interesting stuff!

I cannot agree more, this is one of the most interesting books I have ever read.

Encouraging to hear, it turned up from Amazon earlier! Coincidental. Also arrived is Connectome by Seung - anyone read it yet? Opinions?

Re: Resurgence of Neural Networks

#20

Really interesting stuff. I had once attempted to build a genetic algorithm for manipulating the synapse weights, specifically because of the problems of traditional back-propagation falling into local minima (unfortunately, some serious shit at work made it drop by the wayside). This RBM approach sounds better than back-propagation, but it also sounds like it would be prone to runaway feedback. One of the performanc…

It sounds almost like you want to recreate a Connection Machine [0] using modern(ish) hardware. 0: http://en.wikipedia.org/wiki/Connection_Machine

Yes, I think the advent of cheaply available hardware prototyping is making something like the Connection Machine and Transputers a more viable target for home-grown research. Wouldn't it be neat to be able to make a kit for building one's own Lisp machine, complete with an open, hackable, live-inspectable, Lisp OS? I.e. recreate 40 years ago. How about converting nodes between data storage and processing? There's just a lot of potential fun here.
Post reply on HN