example05.java

本体推理工具 共八个例子:从如何建立本体到做一些简单的的本体推理

        changes.add(new OntologyChangeEvent(computeBMI,OntologyChangeEvent.ChangeType.ADD));

        // We now provide classification of people according to their BMI. For this purpose, we use
        // the kaon2:ifTrue(F,A1,...,An) predicate. In this case, F is the formula written in exactly the
        // same way as for kaon2:evaluate, and Ai are arguments. The extension of this predicate is equal
        // to the set of assertions of the above form where evaluating F on Ai results in Boolean.TRUE.
        Rule isTwig=KAON2Manager.factory().rule(
            KAON2Manager.factory().literal(true,twig,new Term[] { PERSON }),
            new Literal[] {
                KAON2Manager.factory().literal(true,bmi,new Term[] { PERSON,BMI }),
                KAON2Manager.factory().literal(true,KAON2Manager.factory().ifTrue(2),
                    new Term[] {
                        KAON2Manager.factory().constant("$1 < 20"),
                        BMI
                    })
            });
        changes.add(new OntologyChangeEvent(isTwig,OntologyChangeEvent.ChangeType.ADD));

        Rule isNormalWeight=KAON2Manager.factory().rule(
            KAON2Manager.factory().literal(true,normalWeight,new Term[] { PERSON }),
            new Literal[] {
                KAON2Manager.factory().literal(true,bmi,new Term[] { PERSON,BMI }),
                KAON2Manager.factory().literal(true,KAON2Manager.factory().ifTrue(2),
                    new Term[] {
                        KAON2Manager.factory().constant("20 <= $1 && $1 < 25"),
                        BMI
                    })
            });
        changes.add(new OntologyChangeEvent(isNormalWeight,OntologyChangeEvent.ChangeType.ADD));

        Rule isChubby=KAON2Manager.factory().rule(
            KAON2Manager.factory().literal(true,chubby,new Term[] { PERSON }),
            new Literal[] {
                KAON2Manager.factory().literal(true,bmi,new Term[] { PERSON,BMI }),
                KAON2Manager.factory().literal(true,KAON2Manager.factory().ifTrue(2),
                    new Term[] {
                        KAON2Manager.factory().constant("25 <= $1 && $1 < 30"),
                        BMI
                    })
            });
        changes.add(new OntologyChangeEvent(isChubby,OntologyChangeEvent.ChangeType.ADD));

        Rule isWalrus=KAON2Manager.factory().rule(
            KAON2Manager.factory().literal(true,walrus,new Term[] { PERSON }),
            new Literal[] {
                KAON2Manager.factory().literal(true,bmi,new Term[] { PERSON,BMI }),
                KAON2Manager.factory().literal(true,KAON2Manager.factory().ifTrue(2),
                    new Term[] {
                        KAON2Manager.factory().constant("30 <= $1 && $1 < 40"),
                        BMI
                    })
            });
        changes.add(new OntologyChangeEvent(isWalrus,OntologyChangeEvent.ChangeType.ADD));

        Rule isWhale=KAON2Manager.factory().rule(
            KAON2Manager.factory().literal(true,whale,new Term[] { PERSON }),
            new Literal[] {
                KAON2Manager.factory().literal(true,bmi,new Term[] { PERSON,BMI }),
                KAON2Manager.factory().literal(true,KAON2Manager.factory().ifTrue(2),
                    new Term[] {
                        KAON2Manager.factory().constant("$1 > 40"),
                        BMI
                    })
            });
        changes.add(new OntologyChangeEvent(isWhale,OntologyChangeEvent.ChangeType.ADD));

        // We add the axoms to the ontology.
        ontology.applyChanges(changes);

        // We are now ready to see how people are fairing. On general issues related to running queries, pl;ease consult
        // Exmaple 5. We now ask for the BMI of all people:
        Reasoner reasoner=ontology.createReasoner();

        System.out.println("The BMI of people is as follows:");
        System.out.println("--------------------------------");

        Query getBMI=reasoner.createQuery(new Literal[] {
            KAON2Manager.factory().literal(true,bmi,new Term[] { PERSON,BMI })
        },new Variable[] { PERSON,BMI });

        getBMI.open();
        while (!getBMI.afterLast()) {
            Term[] tupleBuffer=getBMI.tupleBuffer();
            System.out.println("The BMI of '"+tupleBuffer[0].toString()+"' is "+tupleBuffer[1].toString()+".");
            getBMI.next();
        }
        // If you don't plan to use a query any more, you don't have to bother closing it; you can
        // simply dispose of it.
        getBMI.dispose();

        System.out.println("--------------------------------");

        // What happened to Chuck? The he wasn't included in this list, since his weight has been specified as a string,
        // which effectively caused a type error. However, KAON2 does not throw an exception on type errors. The reason
        // for this is that exceptions are hard to caputre in logic. Instead, consider what actually happened.
        // The rule for evaluating BMI of chuck was invoked on this literal:
        //
        //   kaon2:evaluate("$1/($2*$2)",184,"74",BMI)
        //
        // This is equivalent to asking whether there is an atomic fact matching this literal. Well, the answer is
        // that there is no such fact, so the rule 'failed' for Chuck. This corresponds to the standard logical notions.

        // Let us now see who the walruses are:
        System.out.println();
        System.out.println("The walruses are:");
        System.out.println("--------------------------------");

        // To get the extension of entire predicate, Reasoner contains the following shortcut:
        Query getWalrus=reasoner.createQuery(walrus);

        getWalrus.open();
        while (!getWalrus.afterLast()) {
            Term[] tupleBuffer=getWalrus.tupleBuffer();
            System.out.println("'"+tupleBuffer[0].toString()+"' is a walrus.");
            getWalrus.next();
        }
        getWalrus.dispose();

        System.out.println("--------------------------------");

        // Do not forget to clean up!
        reasoner.dispose();
        connection.close();
    }
}