Reply to Alexis Wieland

[PH706008%BROWNVM.BITNET@VMA.CC.CMU.EDU]

  In your recent communication concerning the spirals problem for neural
networks, you mentioned that you would be interested in hearing from
anyone working on a related problem.  I have been investigating a similar,
although somewhat less complicated problem, using a backward propagation
network.  The paradigm is a concentric circle problem in which the desired
output on the inner disc is 0 and on the outer annulus is 1.  The two input
units are loaded with the x and y coordinates for each pattern as in your
paradigm.  After learning the training patterns (randomly chosen patterns
in the two regions: usually 50 -150), the network generalizes nicely for
previously unseen patterns; a plot of average output versus radius approaches
that of a step function as more patterns are used.  The paradigm was suggested
by my dissertation advisor, Prof. Leon Cooper.  I would be interested in
hearing more details of your simulations.
       Charles M. Bachmann ("Chip")       ph706008 at Brownvm
       Box 1843 Physics Dpt. &
       Ctr. for Neural Science
       Brown University
       Providence, R. I. 02912