An analog feedback associative memory

• Published in: IEEE transactions on neural networks Vol. 4; no. 1; pp. 117 - 126
• Main Authors: Atiya, A., Abu-Mostafa, Y.S.
• Format: Journal Article
• Language: English
• Published: United States IEEE 01.01.1993
• Subjects: Associative memory; Asymptotic stability; Feedback; Hopfield neural networks; Neural networks; Neurofeedback; Neurons; Pattern recognition; Vector quantization
• ISSN: 1045-9227; 1941-0093
• DOI: 10.1109/72.182701

A method for the storage of analog vectors, i.e., vectors whose components are real-valued, is developed for the Hopfield continuous-time network. An important requirement is that each memory vector has to be an asymptotically stable (i.e. attractive) equilibrium of the network. Some of the limitations imposed by the continuous Hopfield model on the set of vectors that can be stored are pointed out. These limitations can be relieved by choosing a network containing visible as well as hidden units. An architecture consisting of several hidden layers and a visible layer, connected in a circular fashion, is considered. It is proved that the two-layer case is guaranteed to store any number of given analog vectors provided their number does not exceed 1 + the number of neurons in the hidden layer. A learning algorithm that correctly adjusts the locations of the equilibria and guarantees their asymptotic stability is developed. Simulation results confirm the effectiveness of the approach.< >