Added the class Occurrence as a superclass of Event, since it is more generic,...

Added the class Occurrence as a superclass of Event, since it is more generic, that takes place in some location.

Added that an occurrence is detected by some device.

ontology/saref4wear.ttl

@@ -179,6 +179,7 @@ saref:relatesToProperty rdf:type owl:ObjectProperty ;
 
 ###  https://saref.etsi.org/saref4city/takesPlaceAtFacility
 s4city:takesPlaceAtFacility rdf:type owl:ObjectProperty ;
+                            rdfs:subPropertyOf s4wear:takesPlaceAt ;
                             rdfs:isDefinedBy s4city: ;
                             rdfs:label "takes place at facility"@en .
 
@@ -241,6 +242,14 @@ s4wear:isActuatedBy rdf:type owl:ObjectProperty ;
                     rdfs:range saref:Actuator .
 
 
+###  https://saref.etsi.org/saref4wear/isDetectedBy
+s4wear:isDetectedBy rdf:type owl:ObjectProperty ;
+                    rdfs:domain s4wear:Occurrence ;
+                    rdfs:range saref:Device ;
+                    rdfs:comment "Defines the relationship between an occurrence and the device detecting it." ;
+                    rdfs:label "is detected by"@en .
+
+
 ###  https://saref.etsi.org/saref4wear/isLocated
 s4wear:isLocated rdf:type owl:ObjectProperty ;
                  rdfs:domain s4wear:Wearable ;
@@ -303,6 +312,12 @@ s4wear:sendsNotificationsTo rdf:type owl:ObjectProperty ;
                             rdfs:range s4wear:Wearer .
 
 
+###  https://saref.etsi.org/saref4city/takesPlaceAt
+s4city:takesPlaceAt rdf:type owl:ObjectProperty ;
+                    rdfs:comment "The place where an occurrence takes place."@en ;
+                    rdfs:label "takes place at"@en .
+
+
 ###  https://saref.etsi.org/saref4wear/triggers
 s4wear:triggers rdf:type owl:ObjectProperty ;
                 rdfs:domain saref:Device ;
@@ -607,7 +622,8 @@ s4city:CityObject rdf:type owl:Class ;
 
 ###  https://saref.etsi.org/saref4city/Event
 s4city:Event rdf:type owl:Class ;
-             rdfs:subClassOf [ rdf:type owl:Restriction ;
+             rdfs:subClassOf s4wear:Occurrence ,
+                             [ rdf:type owl:Restriction ;
                                owl:onProperty s4city:takesPlaceAtFacility ;
                                owl:allValuesFrom s4city:Facility
                              ] ;
@@ -718,6 +734,16 @@ s4wear:NearBodyWearable rdf:type owl:Class ;
                         rdfs:label "Near-body wearable"@en .
 
 
+###  https://saref.etsi.org/saref4wear/Occurrence
+s4wear:Occurrence rdf:type owl:Class ;
+                  rdfs:subClassOf [ rdf:type owl:Restriction ;
+                                    owl:onProperty s4city:takesPlaceAt ;
+                                    owl:allValuesFrom geosp:Feature
+                                  ] ;
+                  rdfs:comment "An occurrence is the fact of something existing or being found in a place."@en ;
+                  rdfs:label "Occurrence"@en .
+
+
 ###  https://saref.etsi.org/saref4wear/OnBodyWearable
 s4wear:OnBodyWearable rdf:type owl:Class ;
                       rdfs:subClassOf [ owl:intersectionOf ( s4wear:PositionedWearable