Knowledge Representation RDF Turtle Namespace

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1 Knowledge Representation RDF Turtle Namespace Jan Pettersen Nytun, UiA 1

2 URIs Identify Web Resources Web addresses are the most common URIs, i.e., uniform Resource Locators (URLs). RDF resources are usually named by URI references (URIrefs). URIref = URI + optional fragment identifier at the end. E.g., were = URL tom = fragment identifier = namespace Jan Pettersen Nytun, UIA, page 2

3 Full URLs are long. We can define a namespace prefix so we don t have to write the long common part of the rdf: < < rdf:type owl:ntology. Jan Pettersen Nytun, UiA, page 3

4 tandard Namespace For RDF Predefined Terms rdf: Indicates identifiers used in RDF. The set of RDF identifiers is small. The global URI for the rdf namespace is: If you open (e.g., in Internet Explorer) you may see the list of RDF identifiers. Jan Pettersen Nytun, UIA, page 4

5 imple Example Jan Pettersen Nytun, UiA, page 5

6 @prefix : owl: rdf: xml: xsd: rdfs: < < rdf:type owl:ntology. ################################################################# # Classes ################################################################# ### :omeclass rdf:type owl:class. Jan Pettersen Nytun, UiA, page 6

aving as JN-LD [ { "@id" : "http://www.uia.no/janpettersen/pet", "@type" : [ "http://www.w3.

7 aving as JN-LD [ { "@id" : " "@type" : [ " ] }, { "@id" : " "@type" : [ " ] } ] Jan Pettersen Nytun, UiA, page 7

8 Any URI identifier starting with : will be in the default namespace. Jan Pettersen Nytun, UiA, page 8

9 Protégé automatically defines a default namespace corresponding to the IRI of the : owl: < ### :omeclass rdf:type owl:class. Here the default namespace is used. Jan Pettersen Nytun, UiA, page 9

10 Directive directive sets the base URI to be used for the parsing of relative URIs. Jan Pettersen Nytun, UiA, page 10

11 : owl: rdf: xml: xsd: rdfs: < < rdf:type owl:ntology. :omeclass rdf:type owl:class. <TestClass> rdf:type owl:class. How will these be resolved? Jan Pettersen Nytun, UiA, page 11

12 : < :omeclass rdf:type owl:class. <TestClass> rdf:type owl:class. JN-DL utput: [ { "@id" : " "@type" : [ " ] }, { "@id" : " "@type" : [ " ] }, { "@id" : " "@type" : [ " ] } ] Jan Pettersen Nytun, UiA, page 12

13 It can not be set in Protégé; it is automatically set to the same as the ntology IRI Jan Pettersen Nytun, UiA, page 13

14 Merging Graphs [3]: When is a node in one graph the same node as a node in another graph? In RDF, this is solved through the use of Uniform Resource Identifiers (URIs). Jan Pettersen Nytun, UIA, page 14

15 Graph Merging The application is quite simple: A node from one graph is merged with a node from another graph exactly, if they have the same URI. [ref. emanueledellavalle.org]: Jan Pettersen Nytun, UIA, page 15

16 RDF Identifier rdf:type [Ref. Jan Pettersen Nytun, UIA, page 16

17 rdf:type in rdf:type is mostly being described by RDF constructs, e.g., rdfs:domain. Jan Pettersen Nytun, UIA, page 17

Knowledge Representation VII - IKT507. SPARQL stands for SPARQL Protocol And RDF Query Language

Knowledge Representation VII - IKT507 This sentence is false! PARQL stands for PARQL Protocol And RDF Query Language Jan Pettersen Nytun, UiA 1 The emantic Web tack Hierarchy of languages, where each layer