A generalized bidirectional associative memory with a hidden orthogonal layer

Abstract

Hopfield (Hopfield,1984a and 1984b) introduced a first model of one-layer autoassociative memory. The Bidirectional Associative Memory (BAM) was proposed by Kosko (Kosko,1988a) and generalizes the model to be bidirectional and heteroassociative. The BAMs have storage capacity limitations (Wang. 1990a). It has been proposed several improvements (Adaptive Bidirectional Associative Memories (Kosko,1988b). multiple training (Wang. 1990a) y (Wang,1990b), guaranteed recall (Wang,199l) and a lot more besides). One-step models without iteration has been developed too (Orthonormalized Associative Memories (MAON), (Garcia,1992) and the Hao’s associative memory (Hao,1992) which uses a hidden layer). In this paper. we propose a new model of associative memory which can be used either bidirectionally or in one-step mode. This model uses a hidden layer. proper filters and orthogonality to increase the storage capacity and reduce the noise effect arising from linear dependences between patterns. Our model, that we call Bidirectional Associative OrthoGonal Memory (BAOGM) goes beyond the BAM capacity. BAM and MAON models arc particular cases of it.