Sparse distributed memory: Difference between revisions

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Revision as of 19:10, 16 March 2023

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==Definition==

Human memory has a tendency to [[Multiple trace theory|congregate memories]] based on similarities between them (although they may not be related), such as "firetrucks are red and apples are red".<ref name=ship>{{cite web|title=General Psychology|url=http://webspace.ship.edu/cgboer/memory.html|publisher=Shippensburg University|author=C. George Boeree|year=2002}}</ref> Sparse distributed memory is a mathematical representation of human memory, and uses [[Clustering high-dimensional data|high-dimensional space]] to help model the large amounts of memory that mimics that of the human neural network.<ref name=psu>{{cite journal|title=Sparse Distributed Memory and Related Models|pages=50–76|citeseerx=10.1.1.2.8403|publisher=Pennsylvania State University|author=Pentti Kanerva|year=1993}}</ref><ref name=stanford>{{cite web|title=Sparse Distributed Memory: Principles and Operation|url=ftp://reports.stanford.edu/pub/cstr/reports/csl/tr/89/400/CSL-TR-89-400.pdf|publisher=Stanford University|access-date=1 November 2011|author1=M. J. Flynn|author2=P. Kanerva|author3=N. Bhadkamkar|name-list-style=amp|date=December 1989}}{{dead link|date=May 2018 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> An

important property of such high dimensional spaces is that two randomly chosen vectors are relatively far away from each other, meaning that they are uncorrelated.<ref name=integerSDM/> SDM can be considered a realization of [[Localitylocality-sensitive hashing]].

The underlying idea behind a SDM is the mapping of a huge binary memory onto a smaller set of physical locations, so-called ''hard locations''. As a general guideline, those hard locations should be uniformly distributed in the [[virtual memory|virtual space]], to mimic the existence of the larger virtual space as accurately as possible. Every datum is stored distributed by a set of hard locations, and retrieved by averaging those locations. Therefore, recall may not be perfect, accuracy depending on the saturation of the memory.