RDF is short for Resource Description Framework. RDF is the language for describing resources and contents in the semantic web. In the semantic web RDF is used to describe resources on the web. Resources are addressed by a unique URI. A URI looks like a normal Internet URL. Look at the following fragment of a RDF file: <?xml version="1.0"?> <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:owl="http://www.w3.org/2002/07/owl#" xmlns:xsd="http://www.w3.org/2001/XMLSchema#" xmlns="http://example.org/pets#" xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#" xml:base="http://example.org/pets"> <owl:Class rdf:ID="Goldfish"> [...]
Describing things in a way that computer applications can understand it. The semantic web describes relations between concepts. For example: A isPartOf B B hasType C C isMemberOf D Also properties of concepts can be described: A hasAge X B hasSize X C has Length X Where in this case X could be of type Integer.
December 3rd Protege 4.0 was released. So, what is new in this version? First of all it supports the OWL 2.0 specification, which is approaching approval. Other new features in this release are: support for editing multiple ontologies, menu drag and drop user interface elements, the ability to import from repositories on the web and more. Anyway, you can download it here.
Are you getting errors about the “RA layer request failed” and “svn: PROPFIND request failed on ..”, followed by an error about not being able to connect to the SVN server? Well, here is what to do: Install the latest Subclipse plugin for Eclipse. Read the manual at Subclipse Set the right proxy settings at the Subversive-config-file (usuallylocated at C:\Documents and Settings\MyUserId\Application Data\Subversion\servers). At the bottom of the file you’ll find http-proxy-host and http-proxy-port. Uncomment [...]
I am often asked what the differences are between an ontology and a taxonomy. They are often used interchangeable, but what is the real difference? A taxonomy is a classification of things in a certain domain.An ontology describes the world. Some people think of it as putting the universe in a bottle. Look at the following example: TAXONOMY: Cats Related term: Housepets Narrower term: tabby cat, black cat, kitten Broader term: Housepets [...]
"In computer science and information science, an ontology is a formal representation of a set of concepts within a domain and the relationships between those concepts. It is used to reason about the properties of that domain, and may be used to define the domain." (http://en.wikipedia.org/wiki/Ontology_%28information_science%29)
Consider the following set of triples: subject predicate object countries:Germany rdf:type countries:Country countries:Switzerland rdf:type countries:Country countries:UnitedStates rdf:type countries:Country countries:UnitedStates rdfs:label "United States" countries:TheNetherlands rdfs:label "The Netherlands" Select all triples SPARQL Queries are build of statements and triples. When you look at the following query you see a SELECT statement. SELECT ?subject ?predicate ?object WHERE { ?subject ?predicate ?object } With this statement the result is a set of all existing triples. Within the [...]