2. 2
Expert System Main Components
• Knowledge base – obtainable from books,
magazines, knowledgeable persons, etc.
• Inference engine – draws conclusions from the
knowledge base
4. 4
Problem Domain vs. Knowledge
Domain
• An expert’s knowledge is specific to one problem
domain – medicine, finance, science,
engineering, etc.
• The expert’s knowledge about solving specific
problems is called the knowledge domain.
• The problem domain is always a superset of the
knowledge domain.
7. 7
General Methods of Inferencing
• Forward chaining (data-driven)– reasoning from
facts to the conclusions resulting from those facts
– best for prognosis, monitoring, and control.
– Examples: CLIPS, OPS5
• Backward chaining (query driven)– reasoning in
reverse from a hypothesis, a potential conclusion
to be proved to the facts that support the
hypothesis – best for diagnosis problems.
– Examples: MYCIN