Today, we had a WSMO phone conference where we discussed the semantic annotations for RESTful services. I have presented the work done by Amit Sheth and his group on SA-REST (see the presentation below and my previous post).

RESTful services are usually described in a free-text form in HTML while service descriptions (i.e. service contracts) are not explicitly defined. In addition, when creating Web 2.0 applications (mashups), the problem with integration of data produced or consumed by these services is still a remaining issue. A developer must either implement a mediator or change the implementation of a service (if possible) to conform to integration needs. SA-REST introduces a novel approach to annotation of RESTful service description in a HTML using microformats. Semantic descriptions can significantly improve the data integration and automation of service lifecycle. SA-REST proposes to use W3C recommendation where possible, thus the annotation mechanism is based on RDFa and GRDDL

SA-REST, however, does not define any forms of semantic descriptions but assumes that such descriptions will be reused. In this respect, SA-REST is an analogous approach to semantic annotations of WSDL using SAWSDL. In the WSMO WG, we have recently done the work on WSMO-Lite (see our paper in ECOWS 2007 conference) which defines a minimal lightweight service ontology and which can be used for annotations of WSDL services by means of SAWSDL. This is the new approach to augmenting existing service descriptions already available (within or outside of enterprises) in a bottom-up fashion. However, it is important to note that WSMO-Lite is independent on WSDL (and SAWSDL). In this respect, we plan to use WSMO-Lite as a concrete service ontology for annotation of RESTful services, and possibly build on top of SA-REST. This will introduce the second annotation mechanism for WSMO-Lite allowing to use both, WSDL and RESTful services as mechanisms for invocation and communication. We call this annotation mechanism MicroWSMO.

The MicroWSMO together with WSMO-Lite are the core specifications of the upcoming EU funded project SOA4ALL.The goal of this project is to enable SOA architectures in the large-scale Web environment where semantics will play the central role in service provisioning, automation, and scalability.

Knowledge Web project, a four-year EU R&D project, comes to its end by the end of this year. The project forms the Semantic Web community in Europe while contributing to the cutting edge research and development of semantic technologies along the lines of education, research and industry. My major contributions were in the research area with focus on the semantic web and its adoption by web services enabling automation of services tasks. Over the past three years, I worked as the leader of these activities and, thanks to the project, we were able to make a significant contribution in the semantic web services community. Here are our major achievements:

• Development of the WSMO, a service ontology.
• Development of the WSML, a language for Semantic Web Services,
• Development of the WSMX, a middleware system and architecture for Semantic Web Services execution;

Along the above lines, we contributed to the development of the SWS Challenge, a methodology and testbed for the Semantic Web Services as well as solutions for the challenge scenarios, standardizations in OASIS (SEE TC, Semantic Execution Environment Technical Committee), and standardizations in W3C (SAWSDL, Semantic Annotations for WSDL and XML Schema) and published over 60 papers in conferences and journals.

With the end of the project, these activities will not come to the end. We will further continue developing the lightweight ontology for Semantic Web Services (known as WSMO-Lite), services mashups powered by the semantic technologies and related services tasks. There is a number of follow up projects such as SOA4ALL, Service Web 3.0, etc. where all these activities will find its place.