Transcript FT228/4 Knowledge Based Decision Support Systems Rule-Based Systems Ref: Artificial Intelligence A Guide to Intelligent Systems Michael Negnevitsky – Aungier St.

FT228/4 Knowledge Based
Decision Support Systems
Rule-Based Systems
Ref: Artificial Intelligence A Guide to Intelligent Systems
Michael Negnevitsky – Aungier St. Call No. 006.3
Knowledge
Knowledge is a theoretical or practical
understanding of a particular doamin
Knowledge is the sum of what is
currently know
Those who possess knowledge are
termed experts
Knowledge
What is an expert ?
Deep knowledge
Strong practical experience
How do you represent how experts
think?
Knowledge Representation
Programming language is a means of
representing knowledge
Procedural knowledge


“how to”
Knowledge about how to perform some
task
Declarative knowledge

“what is “
Knowledge Representation
Production Rules

IT-THEN expressions
IF some condition(s) exists THEN
perform some action(s)
Test-Action rules
Rule-Based System = Intelligent
Production System
Knowledge Representation
Rule Part 1



Antecedent (premise or condition)
IF part
Test part
Rule Part 2

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
Consequent (conclusion or action)
THEN part
Action part
IF <antecedent> THEN <consequent>
A rule fires when its condition part is
satisified and its action part is executed
Knowledge Representation
Rule can have multiple antecedents



Conjunction AND
Disjunction OR
Or a combination of both
Consequent can have multiple clauses

IF <antecedent> THEN <consequent1>
<consequent2>
<consequentn>
Knowledge Representation
Antecedent consists of


An object (linguistic object)
Its value
Linked by an operator

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
Identifies the object and assigns the value
E.g is, are, is not, are not
Mathematical operators e.g =, >, <
Consequent consists of



An object
A value
Connected by an operator
Knowledge Representation
Rules represent


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Relations
Recommendations
Directives
Strategies
Heuristics
Production System Model
Long Term Memory
Short Term Memory
Production Rule
Fact
Reasoning
Conclusion
Rule-Based System for Tic-TacToe
What rules do we need ?
Rules may have tests that are satisfied
at the same time – need some
mechanism for selecting right rule