setting up namespaces

What is an Ontology?What is an Ontology?

Catalog/ID

GeneralLogical

constraints

Terms/glossary

Thesauri“narrower

term”relation

Formalis-a

Frames(properties)

Informalis-a

Formalinstance

Value Restrs.

Disjointness, Inverse, part-

of…

A Few Observations about OntologiesA Few Observations about Ontologies Simple ontologies can be built by non-experts

Verity’s Topic Editor, Collaborative Topic Builder, GFP, Chimaera, Protégé, OIL-ED, etc.

Ontologies can be semi-automatically generated from crawls of site such as yahoo!, amazon, excite, etc. Semi-structured sites can provide starting points

Ontologies are exploding (business pull instead of technology push) most e-commerce sites are using them - MySimon, Amazon,

Yahoo! Shopping, VerticalNet, etc. Controlled vocabularies (for the web) abound - SIC codes,

UMLS, UN/SPSC, Open Directory (DMOZ), Rosetta Net, SUO Business interest expanding – ontology directors, business

ontologies are becoming more complicated (roles, value restrictions, …), VC firms interested,

DTDs are making more ontology information available Markup Languages growing XML, RDF, DAML, RuleML, xxML “Real” ontologies are becoming more central to applications

Chimaera Chimaera –– A Ontology A Ontology Environment ToolEnvironment Tool

An interactive web-based tool aimed at supporting:•Ontology analysis (correctness, completeness, style, …)•Merging of ontological terms from varied sources•Maintaining ontologies over time•Validation of input

• Features: multiple I/O languages, loading and merging into multiple namespaces, collaborative distributed environment support, integrated browsing/editing environment, extensible diagnostic rule language

• Used in commercial and academic environments

• Available as a hosted service from www-ksl-svc.stanford.edu

• Information: www.ksl.stanford.edu/software/chimaera

Setting Up Namespaces

<rdf:RDF xmlns:rdf ="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#" xmlns:xsd ="http://www.w3.org/2000/10/XMLSchema#" xmlns:daml="http://www.daml.org/2001/03/daml+oil#" xmlns:dex ="http://www.daml.org/2001/03/daml+oil-ex#" xmlns:exd ="http://www.daml.org/2001/03/daml+oil-ex-dt#" xmlns ="http://www.daml.org/2001/03/daml+oil-ex#"

Housekeeping

<daml:Ontology rdf:about=""> <daml:versionInfo>$Id: daml+oil-ex.daml,v

1.8 2001/03/27 21:24:04 horrocks Exp $</daml:versionInfo> <rdfs:comment>

An example ontology, with data types taken from XML Schema </rdfs:comment> followed by

<daml:imports rdf:resource="http://www.daml.org/2001/03/daml+oil">

Defining Classes

<daml:Class rdf:ID="Animal"><rdfs:label>Animal</rdfs:label>

<rdfs:comment> This class of animals is illustrative of a number of ontological idioms. </rdfs:comment>

</daml:Class> <daml:Class rdf:ID="Male">

<rdfs:subClassOf rdf:resource="#Animal"/> </daml:Class>

Defining Classes cont.1<daml:Class rdf:ID="Female"> <rdfs:subClassOf

rdf:resource="#Animal"/> <daml:disjointWith rdf:resource="#Male"/> </daml:Class>

It perfectly admissible for a class to have multiple superclasses: A Man is a Male Person

<daml:Class rdf:ID="Man"> <rdfs:subClassOf rdf:resource="#Person"/> <rdfs:subClassOf rdf:resource="#Male"/> </daml:Class>

...and a Woman is a Female Person.<daml:Class rdf:ID="Woman"> <rdfs:subClassOf

rdf:resource="#Person"/> <rdfs:subClassOf rdf:resource="#Female"/> </daml:Class>

Defining Properties

• <daml:ObjectProperty rdf:ID="hasParent">

• <rdfs:domain rdf:resource="#Animal"/>• <rdfs:range rdf:resource="#Animal"/>• </daml:ObjectProperty> • <daml:ObjectProperty rdf:ID="hasFather">

<rdfs:subPropertyOf rdf:resource="#hasParent"/> <rdfs:range rdf:resource="#Male"/> </daml:ObjectProperty>

Defining Properties cont.1<daml:DatatypeProperty rdf:ID="shoesize">

<rdfs:comment> shoesize is a DatatypeProperty whose range is xsd:decimal. shoesize is also a UniqueProperty (can only have one shoesize)

</rdfs:comment> <rdf:type

rdf:resource="http://www.daml.org/2001/03/daml+oil#UniqueProperty"/>

<rdfs:range rdf:resource="http://www.w3.org/2000/10/XMLSchema#decimal"/> </daml:DatatypeProperty>

Defining Property Restrictions

<daml:Class rdf:ID="Person"><rdfs:subClassOf

rdf:resource="#Animal"/><rdfs:subClassOf> <daml:Restriction>

<daml:onProperty rdf:resource="#hasParent"/> <daml:toClass rdf:resource="#Person"/> </daml:Restriction> </rdfs:subClassOf>

Defining Property Restrictions cont.1

<rdfs:subClassOf> <daml:Restriction daml:cardinality="1">

<daml:onProperty rdf:resource="#hasFather"/> </daml:Restriction>

</rdfs:subClassOf> <rdfs:subClassOf> <daml:Restriction>

<daml:onProperty rdf:resource="#shoesize"/> <daml:minCardinality>1</daml:minCardinality> </daml:Restriction> </rdfs:subClassOf>

Defining Property Restrictions cont.2

• <daml:Class rdf:about="#Animal"> <rdfs:comment> Animals have exactly two parents, ie: If x is an animal, then it has exactly 2 parents (but it is NOT the case that anything that has 2 parents is an animal). </rdfs:comment> <rdfs:subClassOf> <daml:Restriction daml:cardinality="2"> <daml:onProperty rdf:resource="#hasParent"/> </daml:Restriction> </rdfs:subClassOf> </daml:Class> Such an assertion "

Defining Properties cont.1<daml:DatatypeProperty rdf:ID="age">

<rdfs:comment> age is a DatatypeProperty whose range is xsd:decimal. age is also a UniqueProperty (can only have one age) </rdfs:comment>

<rdf:type rdf:resource="http://www.daml.org/2001/03/daml+oil#UniqueProperty"/>

<rdfs:range rdf:resource="http://www.w3.org/2000/10/XMLSchema#nonNegativeInteger"/> </daml:DatatypeProperty>

Defining Properties cont.2

rdf:about="http://www.daml.org/2001/03/daml+oil-ex.daml#Animal"

<daml:Class rdf:about="#Person"> <rdfs:subClassOf> <daml:Restriction daml:maxCardinality="1"> <daml:onProperty rdf:resource="#hasSpouse"/> </daml:Restriction> </rdfs:subClassOf> </daml:Class>

Defining Properties cont.3

<daml:Class rdf:about="#Person"> <rdfs:subClassOf> <daml:Restriction daml:maxCardinality="1"> <daml:onProperty rdf:resource="#hasSpouse"/> </daml:Restriction>

</rdfs:subClassOf> </daml:Class>

Defining Properties cont.4

<daml:Class rdf:about="#Person"> <rdfs:subClassOf> <daml:Restriction daml:maxCardinalityQ="1"> <daml:onProperty rdf:resource="#hasOccupation"/> <daml:hasClassQ rdf:resource="#FullTimeOccupation"/> </daml:Restriction> </rdfs:subClassOf> </daml:Class>

Notations for properties

<daml:UniqueProperty rdf:ID="hasMother"> <rdfs:subPropertyOf rdf:resource="#hasParent"/> <rdfs:range rdf:resource="#Female"/> </daml:UniqueProperty>

Notations for properties cont.1If x's parent is y, then y is x's child. This is defined

using the inverseOf tag.<daml:ObjectProperty rdf:ID="hasChild">

<daml:inverseOf rdf:resource="#hasParent"/> </daml:ObjectProperty>

The hasAncestor and descendent properties are transitive versions of the hasParent and hasChild properties.

<daml:TransitiveProperty rdf:ID="hasAncestor"> <rdfs:label>hasAncestor</rdfs:label> </daml:TransitiveProperty> <daml:TransitiveProperty rdf:ID="descendant"/>

Notations for properties cont.2

Sometimes, we like to refer to mothers using the synonym mom. The tag samePropertyAs allows us to establish this synonymy:

<daml:ObjectProperty rdf:ID="hasMom"> <daml:samePropertyAs rdf:resource="#hasMother"/> </daml:ObjectProperty>

Notations for classes

• <daml:Class rdf:ID="Car"> <rdfs:comment>no car is a person</rdfs:comment>

• <rdfs:subClassOf> <daml:Class> <daml:complementOf rdf:resource="#Person"/> </daml:Class> </rdfs:subClassOf>

Notations for classes cont.1

An even more compact idiom is to state that a whole set of classes are all pairwise disjoint. Rather than stating the individual disjointness relations, this can be stated for a set of classes in a single statement:

<daml:Disjoint rdf:parseType="daml:collection"> <daml:Class rdf:about="#Car"/> <daml:Class rdf:about="#Person"/> <daml:Class rdf:about="#Plant"/> </daml:Disjoint>

Notations for classes cont.2

We can also identify a Class with the disjoint union of a set of other classes. In this case, we identify the Class Person with the disjoint union of the Classes Man and Woman.

<daml:Class rdf:about="#Person"> <rdfs:comment>every person is a man or a woman

</rdfs:comment> <daml:disjointUnionOf

rdf:parseType="daml:collection"> <daml:Class rdf:about="#Man"/> <daml:Class rdf:about="#Woman"/>

</daml:disjointUnionOf> </daml:Class>

Notations for classes cont.3

We have already seen that we can construct a new class by taking the complementOf another class. In the same way, we can construct classes out of the intersection of other classes:<daml:Class rdf:ID="TallMan"> <daml:intersectionOf rdf:parseType="daml:collection"> <daml:Class rdf:about="#TallThing"/> <daml:Class rdf:about="#Man"/> </daml:intersectionOf> </daml:Class>

Notations for classes cont.4

Similarly, we can construct a class as the unionOf a set of classes:<daml:Class rdf:ID="MarriedPerson"> <daml:intersectionOf rdf:parseType="daml:collection"> <daml:Class rdf:about="#Person"/> <daml:Restriction daml:cardinality="1"> <daml:onProperty rdf:resource="#hasSpouse"/> </daml:Restriction> </daml:intersectionOf> </daml:Class>

Notations for classes cont.5

Just as for properties, a mechanism exists for declaring synonyms for classes:

<daml:Class rdf:ID="HumanBeing"> <daml:sameClassAs rdf:resource="#Person"/> </daml:Class>

Using User-defined Datatypes

<xsd:simpleType name="over59"> <!-- over59 is an XMLS datatype based on positiveIntege --> <!-- with the added restriction that values must be >= 59 --> <xsd:restriction base="xsd:positiveInteger"> <xsd:minInclusive

value="60"/> </xsd:restriction> </xsd:simpleType>Then we could reference elements of this file in DAML+OIL restrictions, <daml:Class rdf:ID="Senior"> <daml:intersectionOf rdf:parseType="daml:collection"> <daml:Class rdf:about="#Person"/> <daml:Restriction>

<daml:onProperty rdf:resource="#age"/> <daml:hasClass rdf:resource="http://www.daml.org/2001/03/daml+oil-

ex-dt#over59"/> </daml:Restriction> </daml:intersectionOf> </daml:Class>

Defining individuals

• We can also define individual objects in a class, e.g., Adam, a person of age 13 and shoesize 9.5:<Person rdf:ID="Adam"> <rdfs:label>Adam</rdfs:label> <rdfs:comment> Adam is a person.</rdfs:comment> <age><xsd:integer rdf:value="13"/></age><shoesize><xsd:decimal rdf:value="9.5"/></shoesize> </Person>

Defining individuals cont.1

A Person has a property called hasHeight, which is a Height. (hasHeight is a Property, or relation; Height is a Class, or kind of thing.)

<daml:ObjectProperty rdf:ID="hasHeight"> <rdfs:range rdf:resource="#Height"/> </daml:ObjectProperty>

Defining individuals cont.2

Height is a Class described by an explicitly enumerated set. We can describe this set using the oneOf element. Like disjointUnionOf, oneOf uses the RDF-extending parsetype="daml:collection".

<daml:Class rdf:ID="Height"> <daml:oneOf rdf:parseType="daml:collection"> <Height rdf:ID="short"/> <Height rdf:ID="medium"/> <Height rdf:ID="tall"/> </daml:oneOf> </daml:Class>

Defining individuals cont.3Finally, TallThing is exactly the class of things whose

hasHeight has the value tall: <daml:Class rdf:ID="TallThing"> <daml:sameClassAs> <daml:Restriction> <daml:onProperty rdf:resource="#hasHeight"/> <daml:hasValue rdf:resource="#tall"/> </daml:Restriction> </daml:sameClassAs> </daml:Class>

Defining individuals cont.4

• <daml:DatatypeProperty rdf:ID="shirtsize"> <rdfs:comment> shirtsize is a DatatypeProperty whose range is clothingsize. </rdfs:comment> <rdf:type rdf:resource="http://www.daml.org/2001/03/daml+oil#UniqueProperty"/> <rdfs:range rdf:resource="http://www.daml.org/2001/03/daml+oil-ex-dt#clothingsize"/> </daml:DatatypeProperty> <daml:DatatypeProperty rdf:ID="associatedData"> <rdfs:comment> associatedData is a DatatypeProperty without a range restriction. </rdfs:comment> </daml:DatatypeProperty>

Defining individuals cont.5

• <rdfs:Class rdf:ID="BigFoot"> <rdfs:comment> BigFoots (BigFeet?) are exactly those persons whose shosize is over12. </rdfs:comment> <daml:intersectionOf rdf:parseType="daml:collection"> <rdfs:Class rdf:about="#Person"/> <daml:Restriction> <daml:onProperty rdf:resource="#shoesize"/> <daml:hasClass rdf:resource="http://www.daml.org/2001/03/daml+oil-ex-dt#over12"/> </daml:Restriction> </daml:intersectionOf> </rdfs:Class>

Defining individuals cont.6

• <daml:Class rdf:about="#Person"> <rdfs:comment> Persons have at most 1 item of associatedData </rdfs:comment> <rdfs:subClassOf> <daml:Restriction> <daml:onProperty rdf:resource="#associatedData"/> <daml:maxCardinality>1</daml:maxCardinality> </daml:Restriction> </rdfs:subClassOf> </daml:Class>

Defining individuals cont.7

Now we can (try to) create several individuals. • <Person rdf:ID="Ian"> <shoesize>14</shoesize>

<age>37</age> <shirtsize><xsd:string rdf:value="12"/></shirtsize> </Person>

• <Person rdf:ID="Peter"> <shoesize>9.5</shoesize> <age>46</age> <shirtsize>15</shirtsize> </Person>

• <Person rdf:ID="Santa"> <associatedData><xsd:real rdf:value="3.14159"/></associatedData> <associatedData><xsd:string rdf:value="3.14159"/></associatedData> </Person>