===== MOAT Ontology =====

==== About ====

MOAT defines a [[http://moat-project.org/ns|lightweight ontology]] to represent how different meanings (i.e. URIs of Semantic Web resources) can be related to a tag.

MOAT defines what we call //local meanings// and //global meanings// for each tag.
Global meanings represent the list of all meanings that could be related to a tag in a complete folksonomy space.
Local meanings identifies the given meaning of a tag in a tagging action.

To achieve this goal, the ontology first defines a [[http://moat-project.org/ns#Tag|Tag]] object, that extends the Tag class from [[http://www.holygoat.co.uk/projects/tags/|Richard Newman's tag ontology]].
The main reason is that we consider there is a unique label for each tag between.
Global meanings are then related to a tag thanks to a [[http://moat-project.org/ns#hasMeaning|hasMeaning]] property and a [[http://moat-project.org/ns#Meaning|Meaning]] class.

E.g. Representing a tag labelled "paris", with two different meanings:

<code>
<moat:Tag rdf:about="http://tags.moat-project.org/tag/paris">
<moat:name><![CDATA[paris]]></moat:name>
  <moat:hasMeaning>
    <moat:Meaning>
      <moat:meaningURI rdf:resource="http://sws.geonames.org/2988507/"/>
      <foaf:maker rdf:resource="http://example.org/user/foaf/1"/>
    </moat:Meaning>
  </moat:has_meaning>
  <moat:hasMeaning>
    <moat:Meaning>
      <moat:meaningURI rdf:resource="http://sws.geonames.org/4402452/"/>
      <foaf:maker rdf:resource="http://example.org/user/bob/foaf"/>
      <foaf:maker rdf:resource="http://somwhere.net/myblog/foaf.rdf#me"/>
    </moat:Meaning>
  </moat:has_meaning>
</moat:Tag>
</code>

Local meanings are done thanks to the use of [[http://moat-project.org/ns#RestrictedTagging|RestrictedTagging]] class of the Tag Ontology, combined with a [[http://moat-project.org/ns#tagMeaning|tagMeaning]] property.

Yet, end-users should not have to deal with the ontology, since it is mainly use to let a MOAT [[server]] and [[clients]] share information.

E.g. Representing that the tag labelled "paris" means the french city in a given tagging context:

<code>
<tag:RestrictedTagging>
  <tag:taggedResource rdf:resource="http://example.org/post/1"/>
  <sioc:has_creator rdf:resource="http://example.org/user/sioc/1"/>
  <tag:associatedTag rdf:resource="http://tags.moat-project.org/tag/paris"/>
  <moat:tagMeaning rdf:resource="http://sws.geonames.org/2988507/"/>
</tag:RestrictedTagging>
</code>

The follosing picture represent the main concepts of the MOAT ontology

{{moat_meanings.png|}}

==== Related ontologies ====

MOAT uses [[http://foaf-project.org|FOAF]] and its [[http://xmlns.com/foaf/spec/#term_maker|foaf:maker]] property to define which people consider a URI as the meaning of a Tag. This information can be useful when querying a MOAT server, e.g. to retrieve only meanings that have been given by your friends.

In order to link the (originally tagged) content to the meaningful URI, while the [[http://www.holygoat.co.uk/owl/redwood/0.1/tags/Tagging|Tagging]] class can be used, we suggest to use [[http://sioc-project.org|SIOC]] and especially its [[http://rdfs.org/sioc/spec/#term_topic|sioc:topic]] property.

Finally, related work about ontologies and the Semantic Web can be found in [[http://www.holygoat.co.uk/projects/tags/|Richard Newman's tag ontology]] (used in the MOAT ontology), and the [[http://scot-project.org|SCOT]] project.