Projects/Nepomuk/OntologyBasics - Revision history

AnneW: Marked this version for translation

2012-12-10T17:28:01Z

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AnneW: Prepare for translation

2012-12-10T17:27:45Z

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Vishesh: /* Further Reading */

2012-08-23T15:16:30Z

‎Further Reading

Vishesh: Added Further Reading

2012-08-23T15:15:55Z

Added Further Reading

Vishesh: /* Shared Desktop Ontologies */

2012-08-23T08:31:35Z

‎Shared Desktop Ontologies

Vishesh at 08:21, 23 August 2012

2012-08-23T08:21:40Z

Vishesh: Added some information

2012-08-08T12:54:56Z

Added some information

Vishesh: Added basic structure

2012-08-06T10:24:35Z

Added basic structure

New page

page overview

=Statements=

Talk about subject, predicate, object, graph

=Resources=

What they are - all about

== Collection of Statements ==

== URIs ==

= What is an Ontology =

= RDF and RDFS =
== Type System ==
== Property System ==

= Common Ontologies =
==NFO==
==NIE==
==NMM==
==NMO==

@@ Line 1: / Line 1: @@
-Nepomuk unlike other conventional projects, does not use a relational database to store its data. Instead it uses a RDF store. RDF stands for Resource Description Framework. It's the big framework that was written for describing abstract data on the web, and is the basis of the semantic web. While RDF, has many concepts, Nepomuk mainly utilizes a couple of them.
+<languages />
-=Statements=
+== Introduction ==
-The simplest concept is that of a sentence. All the data in Nepomuk is stored in the form <code><subject> <predicate> <object> <graph></code>. These 4 values combined are called a statement.
+'''Nepomuk''', unlike other conventional projects, does not use a relational database to store its data. Instead it uses a ''RDF store''. RDF stands for Resource Description Framework. It's the big framework that was written for describing abstract data on the web, and is the basis of the semantic web. While RDF, has many concepts, '''Nepomuk''' mainly utilizes a couple of them.
 If we look at this in terms of an object oriented programming language, the <code><subject></code> is an OOP Object, and the (predicate, object) pair can be looked as (key, value) pairs which define properties on that OOP Object.
@@ Line 18: / Line 23: @@
 </syntaxhighlight>
-== Subject ==
+===  Subject ===
-The subject, like in conventional english, is the main part of the sentence. It highlights what we are talking about. In the above example there are different subjects <code>nepomuk:/res/some-uuid</code> and <code>nepomuk:/res/some-other-uuid</code>. In each of these statements the subjects have certain properties and objects bound to them.
-== Predicate ==
+The subject, like in conventional English, is the main part of the sentence. It highlights what we are talking about. In the above example there are different subjects <code>nepomuk:/res/some-uuid</code> and <code>nepomuk:/res/some-other-uuid</code>. In each of these statements the subjects have certain properties and objects bound to them.
 Predicates are often also called properties, and they used to connect the <code><subject></code> with the <code><object></code>.
 Each predicate is generally assigned a domain and range which governs the kind of <subject>s and <object>s it can be connected to.
 Some examples of commonly used predicates are <code>rdf:type</code> [http://oscaf.sourceforge.net/nao.html#nao:lastModified <code>nao:lastModified</code>] and [http://oscaf.sourceforge.net/nao.html#nao:hasTag <code>nao:hasTag</code>]
-== Object ==
+=== Object ===
-The object is the slightly tricky part of statement. Objects can either be uris or literals. Uris refers to other subjects, and literals can be any of the conventional data types - integers, strings, datetime, boolean.
-== Graph ==
+The ''object'' is the slightly tricky part of statement. Objects can either be uris or literals. Uris refers to other subjects, and literals can be any of the conventional data types - integers, strings, datetime, boolean.
-The graph contains some information about the triple - (<subject> <predicate> <object>) such as when it was created, and last modified. Unless you're working on the absolute core parts of Nepomuk, you won't ever have to interact with graphs, and they'll just work seamlessly in the background.
+=== Graph ===
-=Resources=
+The graph contains some information about the triple - (<subject> <predicate> <object>) such as when it was created, and last modified. Unless you're working on the absolute core parts of '''Nepomuk''', you won't ever have to interact with graphs, and they'll just work seamlessly in the background.
 What they are - all about
-== Collection of Statements ==
+=== Collection of Statements ===
-== URIs ==
+=== URIs ===
-= What is an Ontology =
+== What is an Ontology ==
-An ontology is a formal description of the all the properties and types that resources can posses. It can be viewed as the database schema or like the architectural plans.
+An ''ontology'' is a formal description of the all the properties and types that resources can posses. It can be viewed as the database schema or like the architectural plans.
-= RDF and RDFS =
+== RDF and RDFS ==
-The [http://www.w3.org/RDF/ Resource Description Framework] and [http://www.w3.org/2001/sw/wiki/RDFS Resource Description Framework Schema] are the two main schemas that were defined by the Semantic web. They are important because they provide the building blocks for writing all of the other ontologies.
+The [http://www.w3.org/RDF/ Resource Description Framework] and [http://www.w3.org/2001/sw/wiki/RDFS Resource Description Framework Schema] are the two main schemas that were defined by the ''Semantic web''. They are important because they provide the building blocks for writing all of the other ontologies.
 The RDF and RDFS provide the foundation for an entire type system. It is slightly simpler than that of any programming language. It just provides single and multiple inheritance.
@@ Line 65: / Line 74: @@
 We use the <code>rdfs:subClassOf</code> property to indicate one class is a sub-type of another class.
-== Property System ==
+=== Property System ===
 Unlike other conventional system, RDFS also defines a property inheritance system. Each property can be defined a domain, range, cardinality and super-properties.
@@ Line 82: / Line 92: @@
 In the above example a property called <code>nfo:fileName</code> has been declared. This property is a sub-property of the <code>nao:prefLabel</code> ontology.  It additionally defines a <code>nrl:maxCardinality</code> as 1. This indicates that no resource should have more than 1 filename. And finally it defines a domain of <code>nfo:FileDataObject</code> and range of <code>xsd:string</code>.
-Nepomuk currently enforces these ontologies. So if you should always check the domain and range of properties before using them.
+'''Nepomuk''' currently enforces these ontologies. So if you should always check the domain and range of properties before using them.
-= Shared Desktop Ontologies =
+== Shared Desktop Ontologies ==
-The [http://www.oscaf.org/ OSCAF Foundation] was responsible for creating the [http://oscaf.sourceforge.net/ Shared Desktop Ontologies]. Since then the Shared Desktop Ontologies are maintained by the Nepomuk project.
+The [http://www.oscaf.org/ OSCAF Foundation] was responsible for creating the [http://oscaf.sourceforge.net/ Shared Desktop Ontologies]. Since then the ''Shared Desktop Ontologies'' are maintained by the '''Nepomuk''' project.
-The Shared Desktop Ontologies comprise of a large list of ontologies which define types and properties for files, music, messages, contacts and other desktop related things. It also defines NRL - [http://www.semanticdesktop.org/ontologies/nrl/ The Nepomuk Representation Language] which serves as an extension to RDF, and defines the key points of the Semantic Desktop.
+The Shared Desktop Ontologies comprise of a large list of ontologies which define types and properties for files, music, messages, contacts and other desktop related things. It also defines NRL - [http://www.semanticdesktop.org/ontologies/nrl/ The Nepomuk Representation Language] which serves as an extension to RDF, and defines the key points of the ''Semantic Desktop''.
 Here are some of the common ontologies -
@@ Line 98: / Line 108: @@
 * PIMO - [http://www.semanticdesktop.org/ontologies/2007/11/01/pimo/ Personal Information Management Ontology]
-= Further Reading =
+== Further Reading ==
-As Nepomuk is highly dependent on its data in the RDF store, one might consider to read up on RDF and the Nepomuk ontologies:
+As '''Nepomuk''' is highly dependent on its data in the RDF store, one might consider to read up on RDF and the '''Nepomuk''' ontologies:
 * [http://www.w3.org/TR/REC-rdf-syntax/ RDF Primer]
 * [http://www.semanticdesktop.org/ontologies Nepomuk Ontologies]
 * [http://dev.nepomuk.semanticdesktop.org/wiki/OntologyMaintenance Experimental Nepomuk Ontologies and Ideas for new ones]

@@ Line 99: / Line 99: @@
 = Further Reading =
 * [http://www.w3.org/TR/REC-rdf-syntax/ RDF Primer]
 * [http://www.semanticdesktop.org/ontologies Nepomuk Ontologies]
 * [http://dev.nepomuk.semanticdesktop.org/wiki/OntologyMaintenance Experimental Nepomuk Ontologies and Ideas for new ones]

← Older revision		Revision as of 15:15, 23 August 2012
Line 97:		Line 97:
	* NMO - [http://www.semanticdesktop.org/ontologies/nmo/ Nepomuk Messaging Ontology]		* NMO - [http://www.semanticdesktop.org/ontologies/nmo/ Nepomuk Messaging Ontology]
	* PIMO - [http://www.semanticdesktop.org/ontologies/2007/11/01/pimo/ Personal Information Management Ontology]		* PIMO - [http://www.semanticdesktop.org/ontologies/2007/11/01/pimo/ Personal Information Management Ontology]
		+
		+	= Further Reading =
		+
		+	* [http://www.w3.org/TR/REC-rdf-syntax/ RDF Primer]
		+	* [http://www.semanticdesktop.org/ontologies Nepomuk Ontologies]
		+	* [http://dev.nepomuk.semanticdesktop.org/wiki/OntologyMaintenance Experimental Nepomuk Ontologies and Ideas for new ones]

@@ Line 85: / Line 85: @@
 = Shared Desktop Ontologies =
-==NFO==
-==NIE==
+The [http://www.oscaf.org/ OSCAF Foundation] was responsible for creating the [http://oscaf.sourceforge.net/ Shared Desktop Ontologies]. Since then the Shared Desktop Ontologies are maintained by the Nepomuk project.
-==NMM==
-==NMO==
+The Shared Desktop Ontologies comprise of a large list of ontologies which define types and properties for files, music, messages, contacts and other desktop related things. It also defines NRL - [http://www.semanticdesktop.org/ontologies/nrl/ The Nepomuk Representation Language] which serves as an extension to RDF, and defines the key points of the Semantic Desktop.

@@ Line 1: / Line 1: @@
 Nepomuk unlike other conventional projects, does not use a relational database to store its data. Instead it uses a RDF store. RDF stands for Resource Description Framework. It's the big framework that was written for describing abstract data on the web, and is the basis of the semantic web. While RDF, has many concepts, Nepomuk mainly utilizes a couple of them.
 =Statements=
-The simplest concept is that of a sentence. All the data in Nepomuk is stored in the form
+The simplest concept is that of a sentence. All the data in Nepomuk is stored in the form <code><subject> <predicate> <object> <graph></code>. These 4 values combined are called a statement.
-−
-<syntaxhighlight lang="text"><subject> <predicate> <object> <graph></syntaxhighlight>
+If we look at this in terms of an object oriented programming language, the <code><subject></code> is an OOP Object, and the (predicate, object) pair can be looked as (key, value) pairs which define properties on that OOP Object.
-These 4 values combined are called a statement.
-−
-If we look at this in terms of an object oriented programming language, the `<subject>` is an OOP Object, and the (predicate, object) pair can be looked as (key, value) pairs which define properties on that OOP Object.
 Here are some examples of common statements -
@@ Line 32: / Line 25: @@
 Each predicate is generally assigned a domain and range which governs the kind of <subject>s and <object>s it can be connected to.
-Some examples of commonly used predicates are <code>rdf:type</code> <code>nao:lastModified</code> and <code>nao:hasTag</code>
+Some examples of commonly used predicates are <code>rdf:type</code> [http://oscaf.sourceforge.net/nao.html#nao:lastModified <code>nao:lastModified</code>] and [http://oscaf.sourceforge.net/nao.html#nao:hasTag <code>nao:hasTag</code>]
 == Object ==
+The object is the slightly tricky part of statement. Objects can either be uris or literals. Uris refers to other subjects, and literals can be any of the conventional data types - integers, strings, datetime, boolean.
 == Graph ==
@@ Line 50: / Line 43: @@
 = What is an Ontology =
 = RDF and RDFS =
 == Type System ==
 == Property System ==
-= Common Ontologies =
+= Shared Desktop Ontologies =
 ==NFO==
 ==NIE==
 ==NMM==
 ==NMO==