The Semantic Web and its Languages - Semantic Scholar

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On the other hand, its simplicity seriously hampered more advanced web ... Developing new tools, architectures, and applications is the real challenge ...
The Semantic Web and its Languages Dieter Fensel Division of Mathmatics & Computer Science, Vrije Universiteit Amsterdam, De Boelelaan 1081a, 1081 HV Amsterdam, NL, [email protected], http://www.cs.vu.nl/~dieter

Currently computers are changing from single isolated devices to entry points in a world wide network of information exchange and business transactions called the World Wide Web (WWW). Therefore support in data, information, and knowledge exchange becomes the key issue in current computer technology. The WWW has drastically changed the availability of electronically available information. However, this success and exponential grow makes it increasingly difficult to find, to access, to present, and to maintain the information of use to a wide variety of users. In reaction to this bottleneck many new research initiatives and commercial enterprises have been set up to enrich available information with machine processable semantics. Such support is essential for “bringing the web to its full potential” in areas such as knowledge management and electronic commerce. This semantic web will provide intelligent access to heterogeneous and distributed information enabling software products (agents) to mediate between the user needs and the available information sources.1 Originally, the web grew mainly around the language HTML, that provide a standard for structuring documents that was translated by browsers in a canonical way to render documents. On the one hand, it was the simplicity of HTML that enabled the fast growth of the WWW. On the other hand, its simplicity seriously hampered more advanced web application in many domains and for many tasks. This was the reason to define XML (see Figure 1) which allows to define arbitrary domain and task specific extensions (even HTML got redefined as an XML application, see XHTML). Therefore, it is just consequent to define the semantic web as an XML application.

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The first step in this direction is taken by RDF which define a syntactical convention and a simple data model for representing machine-processable semantics of data. The Resource Description Framework (RDF) is a standard for Web meta data developed by the World Wide Web Consortium (W3C).



A second step is taken by the RDF Schema (RDFS) candidate recommendation that defines basic ontological modeling primitives on top of RDF.



A third step is taken by OIL2 that uses RDFS as a starting point and extends it to a full-fledged ontology modeling language. OIL unifies three important aspects

Early steps in the direction of a semantic web where SHOE [Luke et al., 1996] and later Ontobroker [Fensel et al., 1998]. 2 http://www.ontoknowledge.org/oil. The development of OIL is funded via the European IST projects Ibrow and Ontoknowledge.

provided by different communities: Epistemologically rich modeling primitives as provided by the Frame community, formal semantics3 and efficient reasoning support as provided by Description Logics, and a standard proposal for syntactical exchange notations as provided by the Web community. Another candidate for such a web-based ontology modeling language is DAML-O4 funded by DARPA. However, this language is still in its early stage and currently lacks a formal definition of its semantics. Both initiatives cooperate in an US/EU working group to achieve a joined language proposal. Defining languages for the semantic web is just the first step into its direction. Developing new tools, architectures, and applications is the real challenge afterwards. References [Fensel et al., 1998] D. Fensel, S. Decker, M. Erdmann und R. Studer: Ontobroker: The Very High Idea. In Proceedings of the 11th International Flairs Conference (FLAIRS-98), Sanibal Island, Florida, USA, 131-135, Mai 1998. [Luke et al., 1996] S. Luke, L. Spector, and D. Rager: Ontology-Based Knowledge Discovery on the World-Wide Web. In Working Notes of the Workshop on Internet-Based Information Systems at the 13th National Conference on Artificial Intelligence (AAAI96), 1996.

Figure 1. The layer language model for the WWW. DAML-O

OIL

RDFS RDF

XHTML HTML

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Notice that we speak about the semantic web. http://www.daml.org

XML