Semantic Technologies
Contents
SA-WSDL: Semantic Annotated WSDL
Semantic Annotated WSDL enables a semantic interoperability, it is a lightweight annotation mechanism. It is an semantic annotation of WSDL (Web Service Description Language). SA-WSDL is closely derivied from WSDL-S. SA-WSDL is a further development of WSDL-S. Furthermore, SA-WSDL has become more widespread than WSDL-S because it has become a recommendation of the W3C. The advantage of SA-WSDL to WSDL-S is the fact that SA-WSDL allows the inclusion of semantic knowledge structures from extern Ontologies. Both, SA-WSDL and WSDL-S, are agnostic to semantic representation languages.
WSDL-S: Web Service Description Language - Semantics
WSDL is a language for describing Web Services but without taking care about semantic issues. Semantics can improve software reuse and discovery, significantly facilitate composition of Web Services and enable integration of legacy applications as part of business process integration. The WSDL-S specification describes how to add semantic annotations to Web Services. At this WSDL is a standard for describing a Web Service. WSDL-S is an enhancement of WSDL, it provides the WSDL file with semantic annotations. For describing the semantic annotations technologies such as OWL-S are used.
OWL-S: Web Ontology Language for Web Services
OWL-S is a language for describing Web Services with using semantic annotations. Web Service Resource Framework (WSRF) is a recent effort of the grid community to facilitate modeling of the stateful services. Design and development of the WSRF service based systems is quite common and there are several emerging WS initiatives, which tries to automate the process of discovery, composition and invocation of such services. The semantic Web Services are a typical example, showing the potential of how ontological modeling can improve the shortcomings of the service oriented computing. One of the major obstacles in the process is the development of the Ontologies, which describe Web and Grid Services. Although, there are numerous standards for modeling semantic services, there are very few frameworks and tools, which can help to automate the process of generating the semantic descriptions of services. The paper “Generating Semantic Descriptions of Web and Grid Services” [6] presents the non-commercial WSRF2OWL-S tool [7], which can semi-automatically generate the OWL-S descriptions for both stateful and stateless services based on the Web Service Description Language (WSDL) and corresponding annotations. Such functionality is inevitable in the grid environment hosting a vast number of services, which have to be semantically described in order to enable automated discovery, composition and invocation.
OWL-SGN: OWL Semantic Grid Node
The Semantic Grid Node Framework is a new semantic markup language for OWL-SGN based on SGN Framework. Within this framework an ontology-based matchmaker is used. This Framework is a Semantic Grid Node Framework (SGN Framework) which enables a user to structure an ontology of nodes to provide several essential types of knowledge about a node. Therefore the following catalog of questions can be answered through the SGN Framework:
- What do the node require of the user(s), or other agents, and provide for them?
- How does it work and how it can be controlled?
- What user is fit for the node?
- What does the resource provide?
- What relationship between Node and Node?
Fig. 1: Semantic Grid Node Framework [4]
Technology Overview
|
standard |
compatible with OWL |
compatible with RDF |
related to |
SA-WSDL |
yes |
yes |
yes |
further development of WSDL-S |
WSDL-S |
yes |
yes |
? |
should be related to OWL-S |
OWL-S |
yes |
yes |
yes |
|
OWL-SGN |
no standard |
yes |
? |
|
References
Ye Zhang, William Song, “Semantic Description and Matching of Grid Services Capabilities”, University of Durham, URL: http://www.allhands.org.uk/2004/proceedings/papers/205.pdf
John Miller, Kunal Verma, Preeda Rajasekaran, Amit Sheth, Rohit Aggarwal, Kaarthik Sivashanmugam, “WSDL-S: Adding Semantics to WSDL – White Paper”, University of Georgia URL: http://lsdis.cs.uga.edu/library/download/wsdl-s.pdf
Marian Babik, Ladislav Hluchy, Jacek Kitowski, Bartosz Kryza, “Generating Semantic Descriptions of Web and Grid Services”, Institute of Informatics, Slovak Academy of Sciences, Slovakia. Institute of Computer Science, AGH University of Science and Technology, Poland. ACK Cyfronet AGH, Poland. URL: http://web.tuke.sk/fei-cit/babik/babik-dapsys.pdf
The WSRF2OWL-S tool: http://ups.savba.sk/kwfgrid/wsrf2owls/