Development/Tutorials/Metadata/Nepomuk/RDFIntroduction - Revision history

AnneW at 10:48, 15 July 2012

2012-07-15T10:48:06Z

Frederik.gladhorn: /* Other/Custom Ontologies */

2009-11-07T22:52:36Z

‎Other/Custom Ontologies

Trueg at 07:45, 23 August 2009

2009-08-23T07:45:39Z

Trueg: /* RDF and Ontologies in Nepomuk */

2009-08-23T07:42:41Z

‎RDF and Ontologies in Nepomuk

Trueg: /* RDF and Ontologies in Nepomuk */

2009-08-23T07:42:16Z

‎RDF and Ontologies in Nepomuk

Trueg: /* Other/Custom Ontologies */

2009-08-21T07:55:06Z

‎Other/Custom Ontologies

Trueg at 07:53, 21 August 2009

2009-08-21T07:53:04Z

Skierpage: /* Other/Custom Ontologies */ mention and motivate http://www.semanticdesktop.org/ontologies/

2009-07-14T23:39:25Z

‎Other/Custom Ontologies: mention and motivate http://www.semanticdesktop.org/ontologies/

Skierpage: /* RDF - The Resource Description Framework */ better English

2009-07-14T21:17:47Z

‎RDF - The Resource Description Framework: better English

Skierpage: /* RDF - The Resource Description Framework */ motivate uniqueness, link URI

2009-07-14T21:12:48Z

‎RDF - The Resource Description Framework: motivate uniqueness, link URI

← Older revision		Revision as of 10:48, 15 July 2012
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−	~~{{Template:I18n/Language Navigation Bar\|Development/Tutorials/Metadata/Nepomuk/RDFIntroduction}}~~	+

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 ===Other/Custom Ontologies===
-The ontologies mentioned here form the basis of the data in Nepomuk bu they cannot describe every aspect necessary. If you want to store your own data in Nepomuk and link it with other information it is recommended to follow the following process:
+The ontologies mentioned here form the basis of the data in Nepomuk but they cannot describe every aspect necessary. If you want to store your own data in Nepomuk and link it with other information it is recommended to follow the following process:
 * Check if existing standard ontologies provide the classes and properties you need (or some of them).  Many, including NRL and NAO, reside at http://www.semanticdesktop.org/ontologies/.
 * If not, contact [http://sourceforge.net/apps/trac/oscaf/wiki the Oscaf project] with what you need to get help with the discussions and development
 * If that does not help either, start your own ontology and if possible propose it as a standard with Oscaf.

@@ Line 5: / Line 5: @@
 name=RDF and Ontologies in Nepomuk|
 pre=|
-next=[[../ResourceGenerator|Using the Nepomuk Resource Class Generator]]|
+next=[[../ResourceGenerator|Using the Nepomuk Resource Class Generator]],[[../DataLayout|Data Layout in Nepomuk]]|
 reading=[[../Resources|Resource Handling with Nepomuk]],
 [[../AdvancedQueries|Advanced Queries with SPARQL]],

@@ Line 16: / Line 16: @@
 <i>All ontologies discussed here are installed with kdebase-runtime. Thus, they are always in the Nepomuk store. In addition their resource URIs can easily be accessed through the [http://api.kde.org/kdesupport-api/kdesupport-apidocs/soprano/html/namespaceSoprano_1_1Vocabulary.html Soprano::Vocabulary namespace] (except for NIE. But one can easily be created using Soprano'
-s [http://soprano.sourceforge.net/apidox/stable/soprano_devel_tools.html onto2vocabularyclass].</i>
+s [http://soprano.sourceforge.net/apidox/stable/soprano_devel_tools.html onto2vocabularyclass].)</i>
 ===[http://www.w3.org/TR/rdf-primer/ RDF - The Resource Description Framework]===

@@ Line 15: / Line 15: @@
 <i>This tutorial is based on the blog entry [http://www.kdedevelopers.org/node/3276 Nepomuk Appendix A - RDF for Dummies in a Nutshell] by Sebastian Trueg.</i>
-<i>All ontologies discussed here are installed with the kdelibs. Thus, they are always in the Nepomuk store. In addition their resource URIs can easily be accessed through the [http://api.kde.org/kdesupport-api/kdesupport-apidocs/soprano/html/namespaceSoprano_1_1Vocabulary.html Soprano::Vocabulary namespace].</i>
+<i>All ontologies discussed here are installed with kdebase-runtime. Thus, they are always in the Nepomuk store. In addition their resource URIs can easily be accessed through the [http://api.kde.org/kdesupport-api/kdesupport-apidocs/soprano/html/namespaceSoprano_1_1Vocabulary.html Soprano::Vocabulary namespace] (except for NIE. But one can easily be created using Soprano'
 ===[http://www.w3.org/TR/rdf-primer/ RDF - The Resource Description Framework]===

@@ Line 89: / Line 89: @@
 </pre>
-===[http://xesam.org/main/XesamOntology90 Xesam - The Desktop File Metadata Ontology]===
+===[http://www.semanticdesktop.org/ontologies/nie/ NIE - The Nepomuk Information Element Ontology]===
 Xesam is an ontology that has been developed in regards to desktop file indexing tools such as Strigi. It tries to define classes/types and properties for most of the metadata that occurs in files on the desktop. Simple examples include id3 tags or image size or even email data such as sender or recipient.

@@ Line 123: / Line 123: @@
 The ontologies mentioned here form the basis of the data in Nepomuk bu they cannot describe every aspect necessary. If you want to store your own data in Nepomuk and link it with other information it is recommended to follow the following process:
-* Check if the standard ontologies provide the classes and properties you need (or some of them)
+* Check if existing standard ontologies provide the classes and properties you need (or some of them).  Many, including NRL and NAO, reside at http://www.semanticdesktop.org/ontologies/.
 * If not, check [http://dev.nepomuk.semanticdesktop.org/wiki/OntologyMaintenance Nepomuk Ontology Drafts and Proposals] for what you need and help with the discussions and development
 * If that does not help either, start your own ontology and if possible propose it as a standard.

@@ Line 22: / Line 22: @@
 <pre>subject - predicate - object</pre>
 The <i>subject</i> is a resource, the <i>predicate</i> is a relation, and the <i>object</i> is either another resource or a literal value.
-A <i>literal</i> can be a string or an integer or a double or any other type defined by [http://www.w3.org/TR/2004/REC-xmlschema-2-20041028/datatypes.html XML Schema] (actually it is even possible to define custom literal types).
+A <i>literal</i> can be a string, integer, double, or any other type defined by [http://www.w3.org/TR/2004/REC-xmlschema-2-20041028/datatypes.html XML Schema], and it is even possible to define custom literal types.
 Thus RDF can represent statements such as "Mary - is mother of - Carl", or "Mary - was born on - 1970-02-23". These are statements about things, hence RDF is a good technology for ''metadata''.
-To reduce ambiguity, resources and relations need to be uniquely identified; in the example statement above, to identify a particular "Mary", and also to distinguish the family relationship from "Baghdad - is mother of - all battles".
+To reduce ambiguity, resources and relations need to be uniquely identified; for example, in statement above, to identify a particular "Mary", and also to distinguish the maternal relationship from "Baghdad - is mother of - all battles".
 Since RDF was born as a web technology all resources and relations are identified by a ''URI'', [http://en.wikipedia.org/wiki/Uniform_Resource_Identifier Uniform Resource Identifier]. (Hence they have a namespace often ending in a <i>#</i> and a name. Typically abbreviation such as <i>foo:bar</i> are used.) Thus, a dataset in RDF is basically a graph where resources are the nodes, predicates the links, and literals act as leaves.

@@ Line 25: / Line 25: @@
 Thus RDF can represent statements such as "Mary - is mother of - Carl", or "Mary - was born on - 1970-02-23". These are statements about things, hence RDF is a good technology for ''metadata''.
-Since RDF was born as a web technology all resources and relations are identified by their unique URI. (Meaning they have a namespace often ending in a <i>#</i> and a name. Typically abbreviation such as <i>foo:bar</i> are used.) Thus, a dataset in RDF is basically a graph where resources are the nodes, predicates the links, and literals act as leaves.
+To reduce ambiguity, resources and relations need to be uniquely identified; in the example statement above, to identify a particular "Mary", and also to distinguish the family relationship from "Baghdad - is mother of - all battles".
 RDF defines one important default property: <i>rdf:type</i> which allows to assign a type to a resource.