Biology Reference
In-Depth Information
applications without meaning being lost.
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For instance, a Wikipedia
article about Lincoln Stein might have the following RDF:
<rdf:RDF>
<rdf:Description rdf:about=“http://en.wikipedia.org/wiki/Lincoln_Stein”>
<dc:title>Lincoln Stein</dc:title>
<dc:publisher>Wikipedia</dc:publisher>
</rdf:Description>
</rdf:RDF>
The tag structure, which works like HTML code, tells the computer that
this web page is an article about Lincoln Stein published by Wikipedia.
The OWL language goes beyond RDF by including not only a vo-
cabulary, but also a formal semantics that allows terms to be unambigu-
ously related to one another. These relationships provide the basis for
the possibility that machines can perform “useful reasoning tasks” on
web documents.
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OWL's developers explained its necessity as follows:
The World Wide Web as it is currently constituted resembles a
poorly mapped geography. Our insight into the documents and
capabilities available are based on keyword searches, abetted
by clever use of document connectivity and usage patterns. The
sheer mass of this data is unmanageable without powerful tool
support. In order to map this terrain more precisely, computa-
tional agents require machine-readable descriptions of the con-
tent and capabilities of Web accessible resources.
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Just imagine, they continued, asking a search engine, “Tell me what
wines I should buy to serve with each course of the following menu.
And, by the way, I don't like Sauternes.” Or designing software to topic
coherent travel plans. The relationships in OWL would allow software
to “understand” that a wine identifi ed as a “merlot” must also be a
red wine. The power of the Internet is unrealized, Berners-Lee and oth-
ers claimed, because the massive amounts of data are not connected or
organized in any systematic way. RDF and OWL are attempts to solve
this problem by imposing a controlled vocabulary and semantics on the
description of online objects (data, web pages).
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They are “ontologies”
because they aspire to a complete description of all things that exist on
the web and the relationships between them.
As we saw in chapter 4, biology has paid signifi cant attention to its
“ontological” problems, and a wide range of biomedical ontologies al-
