Content-addressability and learning in neural networks

Abstract

The content-addressability of patterns stored in Ising-spin neural network models with symmetric interactions is studied. Numerical results from simulations on the ICL distributed array processor (DAP) involving systems with up to 2048 neurons are presented. Behaviour consistent with finite-size scaling, characteristic of a first-order phase transition, is shown to be exhibited by the basins of attraction of the stored patterns both in the case of the Hopfield model and for systems using a local iterative learning algorithm designed to optimise the basins of attraction. Estimates are obtained for the critical minimum overlaps which an input pattern must have with a stored pattern in order to successfully retrieve it.