Arquivo para July 5th, 2018

Basic Questions of Semantic Web and Ontologies

05 Jul

We are always faced with concepts that seem common sense and are not, is the case of many examples: social networks (confused with the media), fractals (numbers still too generic to be used in everyday life, but important), the artificial intelligence, finally innumerable cases, being able to go to the virtual (it is not the unreal), the ontologies, etc.

These are the cases of Semantic Web and Ontologies, where all simplification leads to an error. Probably so, one of the forerunners of the Semantic Web Tim Hendler, wrote a book Semantic Web for Ontologists modeling (Allemang, Hendler, 2008).

The authors explain in Chapter 3 that when we speak of Semantic Web “of a programming language, we usually refer to the mapping of language syntax to some formalism that expresses the” meaning “of that language.

Now when we speak of ‘semantics’ of natural language, we often refer to something about what it means to understand the utterance – how to go from the structured lyrics or sounds of a language to some kind of meaning behind them.

Perhaps the most primitive part of this notion of semantics is a representation of the connection of a term in a statement to the entity in the world to which the term refers.” (Allemang, Hendler, 2008).

When we talk about things in the world, in the case of the Semantic Web we talk about Resources, as the authors say perhaps this is the most unusual thing for the word resource, and for them a definition language called RDF has been created as a Resource Description Framework, and they on the Web have a basic identification unit called URI, along with a Uniform Resource Identifier.

In the book the authors develop an advanced form of RDF called RDF Plus, which already has many users and developers, to also model ontologies using a language of their own that is OWL, the first application is called SKOS, A Simple Organization of Knowledge, which proposes the organization of concepts such as thesaurus dictionaries, taxonomies and controlled vocabularies in RDF.

Because RDF-Plus is a modeling system that provides considerable support for distributed information and federation of information, it is a model that introduces the use of ontologies in the Semantic Web in a clear and rigorous, though complex, way.

Allemang, D. Hendler, J. Semantic Web for the Working Ontologist: Effective Modeling in RDFS and OWL, Morgan Kaufmann Publishing, 2008.