Semantic Web-Based Information Systems: State-of-the-Art ...

The Human Semant c Web
Figure 2. The learning process modeled as a transformation from inspiring to efficient
fantasies
The.(Machine).Semantic.Web
On the Internet of today, the information is distributed and anyone can link anything
to anything. After all, this is what has made the Web such a great success. However,
the information about the information — the metadata — is still largely centralized
and resides in databases that are hidden behind Web portals. These portals
are advertised by their address with the underlying invitation: Come to our portal
and search our database(s). This stage of Web development could be described as
semantic isolation. It is characterized by the fact that you have to know where a
database is located in order to be able to search in it. Also, the information on an
ordinary HTML Web page is not represented in a way that is semantically interpretable
by machines. For example, imagine that you want to find all the books
written by Shakespeare. If you type the words book and Shakespeare into Google.
com and hit search, you will get hits on Web pages that state things like “this book
is not written by Shakespeare.”
On the Semantic Web, the information about the information (the metadata) can be
represented in such a way so that you can find the books written by Shakespeare. 3
This is most often done by the use of an ontology (Gruber, 2004), which consists of
a set of formally defined terms with relations among them and (possibly) restrictions
in the way that they are used. An ontology is a form of conceptual model, whose
structure is similar to that of a thesaurus with its use of broader and narrower terms,
part-of relationships, and so forth.
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