我正在尝试查看一个本体是否一致。本体可以是一致的,但是仍然可以具有一些无法满足的类。我们称之为Case A。
但是我的问题是,当本体不能通过一致性测试时,即它是没有意义的(情况B)。我的问题是,即使在案例B中,我也无法获得无法满足的本体分类。
我的最终目标是处理不满意的类,以对它们进行一些更改,并使不一致的本体成为一致的本体。因此,我可以在案例A中实现我的目标(我可以访问不满意的类),我可以处理它们并对其进行一些修改。但是,现在,我该如何处理情况B?
以下代码显示了这两种情况。
OWLReasonerFactory reasonerFactory = new PelletReasonerFactory();
OWLReasoner reasoner = reasonerFactory.createNonBufferingReasoner(myOntology);
if (reasoner.isConsistent()) {
if (reasoner.getUnsatisfiableClasses().getEntitiesMinusBottom().size() > 0) {
System.out.println("ontology is consistent but has unsatisfiable classes! FAILED");
// CASE A
} else {
System.out.println("ontology is consistent and safe without any unsatisfiable classes! PASSED");
}
} else {
System.out.println("ontology is inconsistent!FAILED");
// CASE B
}
对于案例B,我该怎么办?在here中,它写道:
如果要查找不满意的类,只需在所有类上调用isSatisfiable方法:
reasoner.isSatisfiable(className);
我在案例B中放置了以下代码:
Iterator<OWLClass> cAll = myOntology.getClassesInSignature().iterator();
while (cAll.hasNext()) {
OWLClass c = cAll.next();
if (!reasoner.isSatisfiable(c)) {
System.out.println("class " + c + "is not satisfibale");
}
}
但出现错误,例如:
Exception in thread "main" org.semanticweb.owlapi.reasoner.InconsistentOntologyException: Inconsistent ontology
at com.clarkparsia.pellet.owlapiv3.PelletReasoner.convert(PelletReasoner.java:360)
at com.clarkparsia.pellet.owlapiv3.PelletReasoner.isSatisfiable(PelletReasoner.java:890)
那么我如何在案例B中处理本体?
不一致的本体意味着存在无法满足的类的实例,或者存在两个或更多个被声明为不相交的类的实例。
(可能,可能有一些人被声明为owl:Nothing类型,但是很容易检测到并且很可能是错误。)
要弄清不一致是否取决于不满意的类,可以尝试将abox和tbox分开-然后单独检查tbox。您可以使用AxiomType中的便捷方法列出属于tbox的公理类型。
更新
基于@Ignazio的评论,在我对问题的原始代码中,代替// CASE B,我将此函数称为:
public static void run(OWLOntology myOnt) {
// save the Tbox and Abox of the original ontology
Set<OWLAxiom> originalTboxAxioms = myOnt.getTBoxAxioms(true);
Set<OWLAxiom> originalAboxAxioms = myOnt.getABoxAxioms(true);
// create new empty ontology
String name = "local_path//name.owl";
OWLOntologyManager manager = OWLManager.createOWLOntologyManager();
File fileM = new File(name);
OWLOntology newOntology = null;
try {
newOntology = manager.createOntology(IRI.create(fileM));
} catch (OWLOntologyCreationException e) {
e.printStackTrace();
}
// add only Tboxes from the orginal ontology to the new one
manager.addAxioms(newOntology, originalTboxAxioms);
// checking the consistency of the new ontology which contain only tbox
OWLReasonerFactory reasonerFactory = new PelletReasonerFactory();
Configuration configuration = new Configuration();
configuration.throwInconsistentOntologyException = false;
OWLReasoner reasoner = reasonerFactory.createNonBufferingReasoner(newOntology, configuration);
if (reasoner.isConsistent()) {
if (reasoner.getUnsatisfiableClasses().getEntitiesMinusBottom().size() > 0) {
Iterator<OWLClass> unClassList = reasoner.getUnsatisfiableClasses().getEntitiesMinusBottom().iterator();
Set<OWLClass> listOfUnsatisfiableClasses = new HashSet<OWLClass>();
while (unClassList.hasNext()) {
/*
* if the unsatisfiable class appear in the original Abox,
* we mark it as an unsatisfiable class
*/
OWLClass myClass = unClassList.next();
if (originalAboxAxioms.contains(myClass))
listOfUnsatisfiableClasses.add(myClass);
}
System.out.println("number of unsatisfiable classes: " + listOfUnsatisfiableClasses.size());
}
}
System.out.println("The ontology is inconsistent but does not have any unsatisfiable classes!!!!!");
}
即使有了这个新功能,也找不到无法满足的要求!
我还尝试了@Ignazio发布的here中的代码。对于给定的示例,该代码将在几秒钟内运行,但是对于我的samll不完善的本体,即使在1天之后,也不会打印任何结果。
还有其他想法如何获取不满意的类及其理由集?