<?xml version="1.0"?>
<!DOCTYPE rdf:RDF [
     <!ENTITY rdf  "http://www.w3.org/1999/02/22-rdf-syntax-ns#" >
     <!ENTITY rdfs "http://www.w3.org/2000/01/rdf-schema#" >
     <!ENTITY xsd  "http://www.w3.org/2001/XMLSchema#" >
     <!ENTITY owl  "http://www.w3.org/2002/07/owl#" >
     <!ENTITY event "http://daml.umbc.edu/ontologies/ittalks/event#" >
   ]>


<rdf:RDF
  xmlns:rdf    = "&rdf;"
  xmlns:rdfs   = "&rdfs;"
  xmlns:owl    = "&owl;"
  xmlns:event  = "&event;"
  xmlns        = "&event;"
  xml:base     = "http://daml.umbc.edu/ontologies/ittalks/event"
>

<owl:Ontology rdf:about="">
  <rdfs:comment> 
	This file defines some abstract concepts, and we will provide 
	assertions about this concepts in a separate file. By doing so,
	we can keep this file in OWL Lite type, and satisfies the basic
	(normally descriptive) usage of such ontology.
	Those assertions are used for further inference.  
	
	This ontology is created by 
		Li Ding -- http://www.csee.umbc.edu/~dingli1/,
	        Harry Chen -- http://www.csee.umbc.edu/~hchen4/,
		Lalana Kagal -- http://www.cs.umbc.edu/~lkagal1/, 
		Tim Finin -- http://www.csee.umbc.edu/~finin/. 
  </rdfs:comment> 			
  <owl:versionInfo>$Revision: 1.1 $</owl:versionInfo>
</owl:Ontology>


<owl:Class rdf:ID="Event">
  <rdfs:label>Event</rdfs:label>
  <rdfs:comment> This is an abstract concept of event.</rdfs:comment> 
</owl:Class>

<owl:Class rdf:ID="Place">
  <rdfs:label>Place</rdfs:label>
  <rdfs:comment> 
	This class defines a abstract concept of spatial place, which 
	has an address. This class is borrowed from CoBrA project. 
	The definition can be found at 
		http://daml.umbc.edu/ontologies/cobra/0.3/place#Place
  </rdfs:comment> 
</owl:Class>


<owl:Class rdf:ID="Instant">
  <rdfs:label>Event</rdfs:label>
  <rdfs:comment> 
	This class defines a abstract concept of instant.
	[Def] an infinitesimal space of time; especially: a point
	      in time separating two states, e.g. at the instant of death
	The definition can be found at 
		http://www.isi.edu/~pan/damltime/time.owl#Instant
  </rdfs:comment> 
</owl:Class>


<owl:Class rdf:ID="IntervalEvent">
  <rdfs:label>One Time Event</rdfs:label>
  <rdfs:subClassOf rdf:resource="#Event" />
  <rdfs:subClassOf>
     <owl:Restriction>
	<owl:onProperty rdf:resource="#location" />
	<owl:minCardinality>1</owl:minCardinality>
     </owl:Restriction>
  </rdfs:subClassOf>
  <rdfs:subClassOf>
     <owl:Restriction>
	<owl:onProperty rdf:resource="#begins" />
	<owl:cardinality>1</owl:cardinality>
     </owl:Restriction>
  </rdfs:subClassOf>
  <rdfs:subClassOf>
     <owl:Restriction>
	<owl:onProperty rdf:resource="#ends" />
	<owl:cardinality>1</owl:cardinality>
     </owl:Restriction>
  </rdfs:subClassOf>
</owl:Class>


<owl:ObjectProperty rdf:ID="location">
  <rdfs:domain rdf:resource="#IntervalEvent"/>
  <rdfs:range rdf:resource="#Place" />
</owl:ObjectProperty>

<owl:ObjectProperty rdf:ID="begins">
  <rdfs:domain rdf:resource="#IntervalEvent"/>
  <rdfs:range rdf:resource="#Instant" />
</owl:ObjectProperty>

<owl:ObjectProperty rdf:ID="ends">
  <rdfs:domain rdf:resource="#IntervalEvent"/>
  <rdfs:range rdf:resource="#Instant" />
</owl:ObjectProperty>

</rdf:RDF>
