WSMO-Lite at ESWC 2008

Published by Tomas  Vitvar on April 25, 2008 in Publications,Research

WSMO-Lite, which describes a lightweight service ontology and annotation mechanism for Web Service Description Language (WSDL), has been accepted for the European Semantic Web Conference 2008 (you can download the paper here).

WSMO-Lite which is currently under the review process in the CMS WG, has been co-authored by Tomas Vitvar, Jacek Kopecky, Jana Viskova and Dieter Fensel. In the paper we define the service ontology describing constructs for services’ information model (ontology) as well as functional services’ descriptions (i.e., categorization, conditions and effects). Using the W3C Semantic Annotations for WSDL and XML Schema (SAWSDL), we define a mechanism for annotation of various WSDL components with WSMO-Lite semantic descriptions. In addition, we define the algorithm to derive the behavioral service descriptions in a form of Abstract State Machines (ASM) from functional annotations (i.e. conditions and effects) of WSDL interface operations and we outline a usage of semantic annotations for a number of services’ use tasks such as service discovery, composition, selection, mediation, etc.

RESTful Services and Semantic Descriptions

Published by Tomas  Vitvar on January 10, 2008 in Ideas,Projects,Research

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.

SAWSDL: Semantic Annotations for WSDL and XML Schema

Published by Tomas  Vitvar on November 2, 2007 in Publications,Research

In November/December, IEEE Internet Computing magazine published our article on the Semantic Annotations for WSDL and XML Schema (SAWSDL). In this article we summarize the results of the W3C SAWSDL Wokring Group.

SAWSDL is the first step in W3C toward standardizing technologies for Semantic Web services. As a standard, SAWSDL provides a common ground for the various ongoing efforts toward SWS frameworks, such as the Web Service Modeling Ontology (WSMO) and the OWL-based Web Service Ontology (OWL-S). SAWSDL extends the major Web service technology WSDL with pointers to semantics that are crucial for achieving automation.

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