Semantic Annotations for WSDL Working Group

This page summarizes the work of the Semantic Annotations for WSDL (SAWSDL) Working Group which was started by W3C in April 2006 and finished in August 2007, after developing a mechanism to enable semantic annotation of Web services descriptions in WSDL 2.0.

Publications

The SAWSDL Working Group has produced the following documents:

SAWSDL Recommendation

• Semantic Annotations for WSDL and XML Schema (Recommendation, 28 August 2007).
• Listing of specification features and Test suite
• Report of SAWSDL implementations

Working Group Note

• Semantic Annotations for WSDL and XML Schema — Usage Guide (Working Group Note, 28 August 2007)

See a listing of related materials below on this page.

Overview

The Web Services Description Language (WSDL) specifies a way to describe the abstract functionalities of a service and concretely how and where to invoke it. The WSDL 2.0 W3C Recommendation does not include semantics in the description of Web services. Therefore, two services can have similar descriptions while meaning totally different things, or they can have very different descriptions yet similar meaning. Resolving such ambiguities in Web services descriptions is an important step toward automating the discovery and composition of Web services — a key productivity enabler in many domains including business application integration.

The Semantic Annotations for WSDL and XML Schema (SAWSDL) W3C Recommendation defines mechanisms using which semantic annotations can be added to WSDL components. SAWSDL does not specify a language for representing the semantic models, e.g. ontologies. Instead, it provides mechanisms by which concepts from the semantic models that are defined either within or outside the WSDL document can be referenced from within WSDL components as annotations. These semantics when expressed in formal languages can help disambiguate the description of Web services during automatic discovery and composition of the Web services.

Based on member submission WSDL-S, the key design principles for SAWSDL are:

• The specification enables semantic annotations for Web services using and building on the existing extensibility framework of WSDL.
• It is agnostic to semantic representation languages.
• It enables semantic annotations for Web services not only for discovering Web services but also for invoking them.

Based on these design principles, SAWSDL defines the following three new extensibility attributes to WSDL 2.0 elements to enable semantic annotation of WSDL components:

• an extension attribute, named modelReference, to specify the association between a WSDL component and a concept in some semantic model. This modelReference attribute can be used especially to annotate XML Schema type definitions, element declarations, and attribute declarations as well as WSDL interfaces, operations, and faults.
• two extension attributes, named liftingSchemaMapping and loweringSchemaMapping, that are added to XML Schema element declarations and type definitions for specifying mappings between semantic data and XML. These mappings can be used during service invocation.

Charter and Participation

The Semantic Annotations for WSDL Working Group operated according to this charter. The group is now closed. The list of the Working Group's participants is available on the WG status page.

The public mailing list used for technical discussions by the Working Group and the public is [email protected] (Archives). An additional list [email protected] (Archives) serves for raising formal comments against the documents published by the group, in particular the Recommendation and the Working Group Note.

Issues Lists

• General SAWSDL Issues List
• (closed) Last Call Working Draft LC Issues List for the 2006-09-28 draft
• (closed) Candidate Recommendation CR Issues List for the 2007-01-26 publication
• (closed) Last Call Working Draft LC Issues List for the 2007-04-10 publication

Tutorials

A set of tutorials on SAWSDL and related Semantic Web technologies is maintained here:

• Kunal Verma and Amit Sheth: Using SAWSDL for Semantic Service Interoperability, Tutorial at Semantic Technology Conference, San Jose, CA, May 21, 2007.

Articles and Presentations

SAWSDL is mentioned in the following papers and articles:

• M. Dimitrov, A. Simov, M. Konstantinov and V. Momtchev: WSMO Studio - a Semantic Web Services Modelling Environment for WSMO (System Description). In ESWC 2007, Proceedings of the 4th European Semantic Web Conference, June 2007, Innsbruck, Austria
• D. Martin, M. Paolucci, and M. Wagner: Towards Semantic Annotations of Web Services: OWL-S from the SAWSDL Perspective. In OWL-S Experiences and Future Developments Workshop at ESWC 2007, June 2007, Innsbruck, Austria
• Kunal Verma and Amit Sheth: Semantically Annotating a Web Service, in IEEE Internet Computing 11 (no. 2), March–April 2007, pp. 83–85.

The following presentations talked about SAWSDL:

• Semantic Annotations for WSDL and XML Schema, Jacek Kopecky, W3C track of WWW2007 Conference, May 2007, Banff, Canada
• SAWSDL: Tools and Applications, Amit Sheth, W3C track of WWW2007 Conference, May 2007, Banff, Canada

Tools, Projects and Applications

Here is a sample of the growing set of tools, projects and applications utilizing SAWSDL. The links below do not imply W3C endorsement or certification of any kind.

SAWSDL is supported and used by the following tools:

• SAWSDL4J by University of Georgia (Athens,GA) and Wright State University (Dayton,OH) (mirror)
• Woden4SAWSDL by University of Georgia (Athens,GA) and Wright State University (Dayton,OH)
• Semantic Tools for Web Services by IBM alphaWorks
• WSMO Studio by Ontotext Lab. and Open University (UK)
• WSMO4J — Grounding API by Ontotext Lab., DERI Innsbruck, DERI Galway (examples)
• Radiant and Lumina by University of Georgia (Athens,GA)

Note: the extent of SAWSDL support in the tools may vary.

In addition to the above tools, the following specifications make use of SAWSDL:

• BPEL4SWS: Process Ontology Language and Operational Semantics for Semantic Business Processes, Project IST 026850 SUPER
• WSMO Grounding, WSMO deliverable
• WSMO-Lite, WSMO deliverable

Patent Policy Disclosures

Patent disclosures relevant to this work may be found on the Working Group's patent disclosure page.

Meeting Agendas and Records

For historical record, here is a list of all the agendas and minutes of the meetings held by the SAWSDL Working Group.

2007-08-21 teleconference: agenda, minutes (these minutes not formally approved)
2007-06-26 teleconference: agenda, minutes
2007-06-19 teleconference: agenda, minutes
2007-06-12 teleconference: agenda, minutes
2007-06-05 teleconference: agenda, minutes
2007-05-29 teleconference: agenda, minutes
2007-05-22 teleconference: agenda, minutes
2007-05-15 teleconference: agenda, minutes
2007-05-08 teleconference: agenda, minutes
2007-04-24 teleconference: agenda, minutes
2007-04-17 teleconference: agenda, minutes
2007-04-10 teleconference: agenda, minutes
2007-04-03 teleconference: agenda, minutes
2007-03-27 teleconference cancelled
2007-03-20 teleconference: agenda, minutes
2007-03-13 teleconference: agenda, minutes
2007-03-06 teleconference: agenda, minutes
2007-02-27 teleconference: agenda, minutes
2007-02-20 teleconference: agenda, minutes
2007-02-13 teleconference: agenda, minutes
2007-02-06 teleconference: agenda, minutes
2007-01-30 teleconference: agenda, minutes
2007-01-23 teleconference: agenda, minutes
2007-01-16 teleconference: agenda, minutes
2007-01-09 teleconference: agenda, minutes
2006-12-12 teleconference: agenda, minutes
2006-12-05 teleconference: agenda, minutes
2006-11-28 teleconference: agenda, minutes
2006-11-21 teleconference: agenda, minutes
2006-11-13 and 14 face-to-face meeting: agenda (member-only), minutes
2006-10-31 teleconference: agenda, minutes
2006-10-24 teleconference: agenda, minutes
2006-10-17 teleconference: agenda, minutes
2006-10-03 teleconference: agenda, minutes
2006-09-26 teleconference: agenda, minutes
2006-09-19 teleconference: agenda, minutes
2006-09-12 teleconference: agenda, minutes
2006-08-30 and 31 face-to-face meeting: agenda (member-only), minutes
2006-08-22 teleconference: agenda, minutes
2006-08-15 teleconference: agenda, minutes
2006-07-25 teleconference: agenda, minutes
2006-07-18 teleconference: agenda, minutes
2006-07-11 teleconference: agenda, minutes
2006-07-04 teleconference: agenda, minutes
2006-06-27 teleconference: agenda, minutes
2006-06-20 and 21 face-to-face meeting: agenda (member-only), minutes
2006-06-13 teleconference: agenda, minutes
2006-06-06 teleconference: agenda, minutes
2006-05-30 teleconference: agenda, minutes
2006-05-23 teleconference: agenda, minutes
2006-05-16 teleconference: agenda, minutes
2006-05-09 teleconference: agenda, minutes
2006-05-02 teleconference: agenda, minutes
2006-04-25 teleconference: agenda, minutes
2006-04-18 teleconference: agenda, minutes
2006-04-11 teleconference: agenda, minutes
2006-04-04 teleconference: agenda, minutes (both member-only)

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