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

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Since p1 <strong>and</strong> p 2 contain tokens <strong>and</strong> the variable bindings for transition tr1<br />

are consistent, tr1 is enabled <strong>and</strong> thus fires, resulting in a new token in<br />

place p3, following the opposite sign of the arc function ¬(Y,X).<br />

Analogously, for transition tr2, the bound value of variables is<br />

¬X= ¬k , ¬Y= ¬l (see token at place p4 <strong>and</strong> the associated arc function)<br />

X= k (see token at place p5 <strong>and</strong> the associated arc function)<br />

∴the consistent bindings are X= k , Y= l .<br />

P1<br />

Father<br />

<br />

(X,Y)<br />

tr1<br />

¬(Y,X)<br />

¬(Y,X)<br />

P5<br />

¬<br />

Daughter<br />

Female<br />

< k ><br />

Fig. 8.14: A Petri net of fig. 8.13 with tokens.<br />

Since the output place p4 <strong>and</strong> one of the two input places p5 contains<br />

consistent bindings, transition tr2 fires, resulting in a new token at place p3.<br />

The value of the token is ¬, following the opposite sign of the arc<br />

function (Y, X). So, at place p3 we have two resulting tokens ¬ <strong>and</strong> . It may be noted that these two tokens can be generated concurrently.<br />

Chapter 22 covers in detail the concurrent realization of the Petri net models.<br />

8.9 Conceptual Dependency<br />

(Y,X)<br />

¬ (X,Y)<br />

¬ <br />

Conceptual dependency, abbreviated as CD, is a specialized structure that<br />

describes sentences of natural languages in a symbolic manner. One<br />

significant feature of CD is its structural independence on the languages in<br />

Son<br />

P3<br />

P2<br />

(X) tr2<br />

Mother<br />

P4

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