Conclusion and Outlook - Enabling Semantic Web Services: The Web Service Modeling Ontology - page 165

leases of the ebXML 3 specifications and other work on Web services and
service-oriented architectures. The OASIS SOA Adoption Blueprints Tech-
nical Committee has recognized the shortage of clear, illustrative examples
of working implementations of SOAs based on real-world needs and require-
ments that can be used as references for best practice and is working in this
direction. Finally, the OASIS Web Services Resource Framework (WSRF)
Technical Committee is defining a generic, open framework for modeling and
accessing stateful resources using Web services. This includes mechanisms to
describe views of the state of a Web service (or any other Web resource),
to support management of this state through properties associated with the
Web service, and to describe how these mechanisms are extensible to groups
of Web services.
The W3C is not addressing issues specifically related to service-oriented
architectures, but the results of several W3C working groups are crucial to
the realization of Semantic Web services in that they focus on specific aspects
on Web services and the Semantic Web.
The Semantic Annotations for WSDL Working Group aims to add min-
imal semantic extensions to WSDL. WSDL itself only specifies a way to de-
scribe the abstract functionalities of a service and concretely how and where
to invoke it. The WSDL 2.0 specification, however, does not include seman-
tics in service descriptions, and thus two services can have similar descriptions
but totally different meanings or, vice versa, similar meanings with completely
different descriptions. The objective of the Semantic Annotations for WSDL
Working Group is to develop a mechanism to enable semantic annotation of
WSDL descriptions. This mechanism will take advantage of the WSDL 2.0
extension mechanisms to build simple, generic support for semantics in Web
services.
The Rule Interchange Format Working Group is chartered to specify a
format for rules, such that they can be used across diverse systems. It aims to
create a common format for static and dynamic business rules. This format
(or language) will function as an interlingua into which established and new
rule languages can be mapped, allowing rules written for one application to
be published, shared, and reused in other applications and other rule engines.
This is essentially along the same lines as the WSML language. One motivation
for creating WSML was that at the time of starting the effort there was no
rule language that fullfilled our requirements of (1) a clear layering, and (2)
declarative semantics based on well established and proven formalism that (3)
is compliant with Web technologies such as URIs, XML, and RDF.
Summarizing, while SOAs are widely accepted as the next generation of
computing to which most software vendors are committed, standards are still
evolving. From 2000 to 2005, SOA standard proposals grew enormously in
number and complexity, with few reference technologies. Some standards al-
ready exist, while others are scheduled for development and release up to 2012
3 http://www.ebxml.org .