provides a mechanism for constructing specialized RDF vocabularies through the description of domain-specific properties. This is obtained mainly by describing the properties in terms of the classes of resource to which they apply: for example, we could define the creator property saying that it has the resource document as ‘domain’ (document is the value or ‘object’ of this property) and the resource person as ‘range’ (this property must always be associated with a resource person, its ‘subject’). Other basic modelling primitives of RDFS allow setting up hierarchies (taxonomies), both hierarchies of concepts thanks to the use of class and subclass-of statements, and hierarchies of properties thanks to the use of property and subproperty-of statements. Instances of a specific class (concept) can be declared making use of the type statement.
Published in Chapter:
Using Semantic Web Tools for Ontologies Construction
Gian Piero (University of Paris IV / Sorbonne, France)
Copyright: © 2009
|Pages: 16
DOI: 10.4018/978-1-60566-242-8.ch046
Abstract
The current state of Web technology – the “first generation” or “syntactic” Web – gives rise to well-known, serious problems when trying to accomplish, in a non-trivial way, essential tasks like indexing, searching, extracting, maintaining, and generating information. These tasks would, in fact, require some sort of ‘deep understanding’ of the information dealt with: in a “syntactic” Web context, on the contrary, computers are only used as tools for posting and rendering information by brute force. Faced with this situation, Tim Berners- Lee first proposed a sort of “Semantic Web” where the access to information is based mainly on the processing of the semantic properties of this information: “… the Semantic Web is an extension of the current Web in which information is given well-defined meaning (emphasis added), better enabling computers and people to work in co-operation” (Berners-Lee et al., 2001: 35). The Semantic Web’s challenge consists of being able to access and retrieve information on the Web by “understanding” its proper semantic content (its meaning), and not simply by matching some keywords.