188 ◾ Leszek Lilien et al.
© 2011 by Taylor & Francis Group, LLC
service are used in service matching, ignoring the nonfunctional properties, such as
QoS requirements. Nonfunctional properties add extra service-matching criteria,
thus narrowing the number of functionally equivalent Web services.
7.3.2.1 Semantic Web Service Specification
Approaches facilitating a semantic specication of Web services include the following:
◾ e DARPA program [59] proposed DARPA Agent Markup Language
(DAML), which extends XML and RDF. e Ontology Inference Layer
(OIL) adds the underlying ontology layer to the Semantic Web. DAML and
OIL were succeeded by DAML+OIL, which includes features of both its pre-
decessors, and evolved into the Ontology Web L ...