The Concepts of WSMO - Enabling Semantic Web Services: The Web Service Modeling Ontology - page 60

Class ontology
hasNonFunctionalProperty type nonFunctionalProperty
importsOntology type ontology
usesMediator type ooMediator
hasConcept type concept
hasRelation type relation
hasFunction type function
hasInstance type instance
hasAxiom type axiom
6.1.1 Nonfunctional Properties
Nonfunctional properties are applicable to all the definitions of WSMO ele-
ments. Note that in some cases WSMO specifically recommends that certain
properties should be applicable to an element, but this does not impact the
general considerations presented here. Nonfunctional properties are mainly
used to describe nonfunctional aspects such as the creator and the creation
date, and to provide natural-language descriptions, etc. The elements defined
by the Dublin Core Metadata Initiative [134] are taken as a starting point.
Dublin Core is a set of attributes that define a standard for cross-domain
information resource description. In WSMO, we use URIs for identification of
elements, which are reused. WSMO proposes several extensions to this set by
introducing new attributes, such as the version element which can contain in-
formation about the particular version of an element. The set of nonfunctional
properties that WSMO recommends are informally presented in Section 6.5.
6.1.2 Imported ontologies
Building an ontology for a particular problem domain can be a rather cum-
bersome and complex task. One standard way to deal with the complexity is
modularization. Imported ontologies allow a modular approach to ontology
design and can be used as long as no conflicts need to be resolved between
the ontologies. When ontologies are imported, all statements of the imported
ontology will be virtually included in the importing ontology. Every WSMO
top-level entity may use this import facility to include the logical definition
of the vocabulary used.
6.1.3 Mediators
When ontologies are imported in realistic scenarios, some steps are needed
for aligning, merging and transforming the imported ontologies in order to
resolve ontology mismatches. For this reason and in line with the basic de-
sign principles underlying the WSMF, ontology mediators (OO mediators),
whicharedescribedindetailinSection6.4,areusedwhenanalignmentof
an imported ontology is necessary. Such an alignment can be done by sim-
ply renaming concepts, attributes or the like. Just like the importsOntology
statement, the usesM ediator statement is applicable to all top-level elements,
however depending on the element, different mediators may be used.