Best Probability of Activation and Performance Comparisons for Several Designs of Sparse Distributed Memory

Abstract

The optimal probability of activation and the corresponding performance is studied for three designs of Sparse Distributed Memory, namely, Kanerva's original design, Jaeckel's selected-coordinates design and Karlsson's modification of Jaeckel's design. We will assume that the hard locations (in Karlsson's case, the masks), the storage addresses and the stored data are randomly chosen, and we will consider different levels of random noise in the reading address. Keywords: Sparse Distributed Memory, Probability of Activation, Performance Contents 1. Introduction 2 2. General definitions and assumptions 2 3. The error probability and the signal-to-noise ratio 4 4. Determination of the signal-to-noise ratio 5 5. Discussion of the normal approximation of Z 9 6. Discussion of the randomness assumptions for hard locations, storage addresses etc. 10 7. Numerical calculations 12 8. Summary and conclusions 13 References 13 Tables 14 1 Real World Computing Partnership 2 Swedish Institute of C..