worden@ut-emx.UUCP (worden) (08/11/89)
It seems to me that most NN folks are doing their honest best with what little we know now. (And a thousand curses on those few but vociferous money-sniffer dilettantes!!) As I understand it, our sensory and motor systems are highly structured, from the peripheral nerves to at least several cortical layer depths. Beyond that, through the association areas and into the deeper structures of the limbic system, no one really knows what the h--l is going on. So, it doesn't surprise me that most NN folks work with the structured networks. After all, there can thereby be hope that one's model will be biologically verified. And, such work is not without merit; there remains a great deal to be understood, even in the sensory/motor systems about which we know the most. My personal preference, however, is for the random type of networks. Not as sensory/motor systems, but as possible models of the deeper systems. I have a nice micrograph, from the old 1979 Scientific American special issue on the brain, that shows a tangled mass of stained brain tissue. Apparent randomness, at least, does seem to coexist with structure inside our skulls! What I would really like to see, though, if it is not too premature, is collaboration between you majority structure enthusiasts and us minority randomness aficionados, along with some A.I. folks, to seriously attempt to build a "complete" system. My thought would be to use structured NN's for sensor input/processing and low-level learning, feeding into random NN's for multisensor fusion and mid- level learning, feeding into an A.I. subsystem for high- level learning and decision-making, feeding into random NN's for multi-effector fission, feeding into structured NN's for pre-effector conditioning and effector output. By the way, if any of you have any references to recent collaborative work between structured NN and A.I. folks, I would be very interested in getting them. Please email the info to me (or to this newsgroup). Finally, I believe that all of us are lacking critical, fundamental knowlege of some kind about how our brains work and that it is this deficiency that now prevents us from building systems that behave the way we would really like (i.e., in a "truly intelligent" fashion). I just cannot buy the arguments that greater size or greater speed or greater complexity or even greater biological realism is the "answer". I do believe that part of the answer lies in building hybrid systems, but I think that there is a deeper mystery. Perhaps some cellular function that has yet to be observed and/or understood. Perhaps an interaction between neurons and glia, as suggested by that recent Scientific American article. Perhaps some phenomenon that we don't even suspect at this point... - Sue Worden Electrical and Computer Engineering University of Texas at Austin
jk3k+@andrew.cmu.edu (Joe Keane) (08/13/89)
In article <16946@ut-emx.UUCP> worden@ut-emx.UUCP (worden) writes: >As I understand it, our sensory and motor systems are highly >structured, from the peripheral nerves to at least several >cortical layer depths. Beyond that, through the association >areas and into the deeper structures of the limbic system, >no one really knows what the h--l is going on. Not yet at least. >Apparent randomness, at least, does seem to coexist with >structure inside our skulls! If you looked at a microprocessor chip you might say the same thing. I don't think biological neural nets are as structured as silicon chips, or we might be looking for `grandmother cells'. But i don't think they're completely random either. It's up to NN people and neurobiologists to figure out which structures are useful.