Chapter 1 Introuction to Expert Systems1章介绍了专家系统.pptVIP

* * * * * * * * * * * * * * * * * * * * * * * * * * * * Expert Systems: Principles and Programming, Fourth Edition * Test Condition A rule will be triggered only if all its test CEs are satisfied along with other patterns. (test predicate-function) Example: (test ( ?value 1)) Expert Systems: Principles and Programming, Fourth Edition * Predicate Field Constraint The predicate field constraint : allows for performing predicate tests directly within patterns. The predicate field constraint is more efficient than using the test CE. It can be used just like a literal field constraint – by itself or part of a complex field. The predicate field constraint is always followed by a function for evaluation (predicate function). Expert Systems: Principles and Programming, Fourth Edition * Return Value Constraint The return value constraint = allows the return value of a function to be used for comparison inside a pattern. The return value constraint must be followed by a function (not necessarily a predicate function). The function must have a single-field return value. Expert Systems: Principles and Programming, Fourth Edition * The OR Conditional Element Consider the two rules: Expert Systems: Principles and Programming, Fourth Edition * OR Conditional Element These two rules can be combined into one rule – or CE requires only one CE be satisfied: Expert Systems: Principles and Programming, Fourth Edition * The And Conditional Element The and CE is opposite in concept to the or CE – requiring all the CEs be satisfied: Expert Systems: Principles and Programming, Fourth Edition * Not Conditional Element When it is advantageous to activate a rule based on the absence of a particular fact in the list, CLIPS allows the specification of the absence of the fact in the LHS of a rule using the not conditional element: Expert Systems: Principles and Programming, Fourth Edition * Not Conditional We can implement this as follows: Expert Systems: Principles and Progra