Computational Intelligence and Neuroscience / 2013 / Article / Tab 2

Research Article

A Functional Model of Sensemaking in a Neurocognitive Architecture

Table 2

The list of sub-symbolic mechanisms in the ACT-R architecture.

Mechanism EquationDescription

Activation : base-level activation reflects the recency and frequency of use of chunk i  
: spreading activation reflects the effect that buffer contents have on the retrieval process  
: partial matching reflects the degree to which the chunk matches the request  
: noise value includes both a transient and (optional) permanent components (permanent component not used by the integrated model)

Base level : the number of presentations for chunk i  
: the time since the jth presentation 
: a decay rate (not used by the integrated model)  
: a constant offset (not used by the integrated model)

Spreading activation : weight of buffers summed over are all of the buffers in the model  
: weight of chunks which are in the slots of the chunk in buffer k  
: amount of activation from sources j in buffer k  
: strength of association from sources j to chunk i
: the maximum associative strength (set at 4 in the model)  
: a measure of how many chunks are associated with chunk j

Partial matching : match scale parameter (set at 2) which reflects the weight given to the similarity  
: similarity between the value k in the retrieval specification and the value in the corresponding slot of chunk i  
The default range is from 0 to −1 with 0 being the most similar and −1 being the largest difference

Declarative retrievals : the probability that chunk will be recalled  
: activation strength of chunk   
: activation strength of all of eligible chunks   
: chunk activation noise

Blended retrievals : probability from declarative retrieval  
: similarity between compromise value and actual value

Utility learning , : utility of production i after its application  
: reward production received for its nth application  
: utility of production i after its nth application
: probability that production i will be selected  
: expected utility of the production determined by the utility equation above  
: is the expected utility of the competing productions j

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