Adaptive Resonance Theory Architecture

Introduction:- The Architecture of ART1 neural network consist of two layers of neurons.

ATR1 model consists an "Attentional" and an "Orienting" subsystem. The Attentional sub-system consists of :

•  two competitive networks, as Comparison layer F1 and Recognition layer F2, fully connected with top-down and bottom-up weights;
•  two control gains, as Gain1 and Gain2.

The pattern vector is input to comparison layer F1

The Orienting sub-system consists of :

• Reset layer for controlling the attentional sub-system overall dynamics based on vigilance parameter.
• Vigilance parameter ρ determines the degree of mismatch to be tolerated between the input pattern vectors and the weights connecting F1 and F2.

The nodes at F2 represent the clusters formed. Once the network stabilizes, the top-down weights corresponding to each node in F2 represent the prototype vector for that node.

ART1 Model Description:-The ART1 system consists of two major subsystem, an attentionalsubsystem and an orienting subsystem, described below. The systemdoes pattern matching operation during which the network structuretries to determine whether the input pattern is among the patternspreviously stored in the network or not.

Attentional Subsystem

(a) F1 layer of neurons/nodes called or input layer or comparison layer; short term memory (STM).

(b) F2 layer of neurons/nodes called or output layer or recognition layer; short term memory (STM).

(c) Gain control unit , Gain1 and Gain2, one for each layer.

(d) Bottom-up connections from F1 to F2 layer ; traces of long term memory (LTM).

(e) Top-down connections from F2 to F1 layer; traces of long term memory (LTM).

(f) Interconnections among the nodes in each layer are not shown.

(g) Inhibitory connection (-ve weights) from F2 layer to gain control.

(h) Excitatory connection ( ve weights) from gain control to F1 and F2.

Orienting Subsystem

(h) Reset layer for controlling the attentional subsystem overall dynamics.

(i) Inhibitory connection (-ve weights) from F1 layer to Reset node.

(j) Excitatory connection ( ve weights) from Reset node to F2 layer