“Characteristics of Sparsely Encoded Associative Memory”, 1989 (; backlinks):
Characteristics of an autocorrelation or cross-correlation associative memory largely depend on how items are encoded in pattern vectors to be stored. When most of the components of encoded patterns to be stored are 0 and only a small ratio of the components are 1, the encoding scheme is said to be ‘sparse’.
The memory capacity and information capacity of a sparsely encoded associative memory are analyzed in detail, and are proved to be in proportion of n2 / log(n2), n being the number of neurons, which is very large compared to the ordinary non-sparse encoding scheme of about 0.15n.
Moreover, it is proved that the sparsely encoded associative memory has a large basin of attraction around each memorized pattern, when and only when an activity control mechanism is attached to it.