Information Technology Reference
In-Depth Information
For classifier system-based learning, environment is required to be capable of
providing feedback and affirming whether the wanted state arrives or not. The
system will validate these rules' effectiveness. These activities are usually called
credit assignment, such as barrel chain algorithm.
The last level is discovery subsystem, which generates new rules and
substitutes some rules of little usefulness. The system generates rules by
cumulative experiences, and performs genetic selection, recombination and
substituting rules according to fitness.
discovery
[genetic algorithm ]
credit assignment
[barrel chain ]
receiving message
input interface
sending message
output interface
execute
[classifier system ]
payment
message from internal monitor
(goal)
Fig.13.3. General structure of classifier system
Classifier system is a system which is executed concurrently and based on
message passing and rules. In a simple way, a message is expressed with a given
character set and fixed length. All the rules are expressed in the form of
“condition/action”. Each condition defines all the required information, and then
each action defines related message to be sent when the condition is satisfied. For
simplicitysuppose that a message is expressed with a binary character string
whose length is l and character set is {1,0,#}, where # means that it can match
both 1 and 0. For example, the character string 11···1# defines a subset consisting
