06.03.2013 Views

Artificial Intelligence and Soft Computing: Behavioral ... - Arteimi.info

Artificial Intelligence and Soft Computing: Behavioral ... - Arteimi.info

Artificial Intelligence and Soft Computing: Behavioral ... - Arteimi.info

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

21.3.2 Inconsistencies in Knowledge Bases<br />

The following four types of inconsistencies are discussed in this section.<br />

1. Redundant Rule: A rule is called redundant in a set of rules S, if all<br />

the predicates in the antecedent part of more than one rule in S are<br />

identical, the order of the predicates in the antecedent part of the rule<br />

being immaterial. For example, one of the following two rules is<br />

redundant.<br />

Rule 1: R ← P1, P2, P3.<br />

Rule 2: R ← P2, P3, P1.<br />

It is to be noted that the Petri net representation of both the above rules<br />

is identical.<br />

2. Subsumed Rule: If the consequent part of two rules includes some<br />

predicate, <strong>and</strong> the antecedent predicates of one rule are the subset of the<br />

antecedent predicates of the other rule, then the latter rule is called<br />

‘subsumed’. In the following set of rules, rule 2 is subsumed.<br />

S<br />

R<br />

Rule 1: P ← Q, R.<br />

Rule 2: P ← Q, R, S.<br />

W<br />

tr2<br />

tr2 T<br />

Fig. 21.10: Representation of a circular rule.<br />

tr1<br />

T<br />

P<br />

tr3<br />

Q

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!