??? The region-distance ontology shown in Figure
4 is used to represent knowledge about distance between two regions.
Figure 5 describes the ontology of Figure 4 as a semantic graph form. RDFS defines
a property??™s domain??”resources that can be subjects of the property, and a property??™s
ranges??”resources that can be objects of a property. For example, the property has-
Distance may have a class Region as its domain and a class Distance as its range.
In OWL, there are two types of properties: object property and datatype property.
The former relates objects to other objects. The latter relates objects to datatype values.
OWL provides a powerful mechanism for enhanced reasoning about a property
(World Wide Web Consortium, 2004a). Table 1 summarizes property characteristics
for those depicted in Figure 4. For example, hasDistance and givenToRegion are
ObjectProperty and there is an inverse relation between them. A region have dis-
Application of the Semantic Web Based on the Domain-Specific Ontology 295
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