Monthly
288 pp. per issue, 6 x 9,
illustrated
Founded: 1989
ISSN 0899-7667
E-ISSN 1530-888X
2008 ISI Impact Factor: 2.378
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June 1, 2001, Vol. 13, No. 6, Pages 1379-1414
Posted Online March 13, 2006.
(doi:10.1162/08997660152002898)
© 2001 Massachusetts Institute of Technology
Attractive Periodic Sets in Discrete-Time Recurrent Networks (with Emphasis on Fixed-Point Stability and Bifurcations in Two-Neuron Networks) Peter TiňoAston University, Birmingham B4 7ET, U.K., and Department of Computer Science and Engineering, Slovak University of Technology, 812 19 Bratislava, Slovakia Bill G. HorneNEC Research Institute, Princeton, NJ 08540, U.S.A. C. Lee GilesNEC Research Institute, Princeton, NJ 08540, U.S.A., and School of Information Sciences and Technology, Pennsylvania State University, University Park, PA 16801, U.S.A.
We perform a detailed fixed-point analysis of two-unit recurrent neural networks with sigmoid-shaped transfer functions. Using geometrical arguments in the space of transfer function derivatives, we partition the network state-space into distinct regions corresponding to stability types of the fixed points. Unlike in the previous studies, we do not assume any special form of connectivity pattern between the neurons, and all free parameters are allowed to vary. We also prove that when both neurons have excitatory self-connections and the mutual interaction pattern is the same (i.e., the neurons mutually inhibit or excite themselves), new attractive fixed points are created through the saddle-node bifurcation. Finally, for an N-neuron recurrent network, we give lower bounds on the rate of convergence of attractive periodic points toward the saturation values of neuron activations, as the absolute values of connection weights grow.
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