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Delivering the Power of Net-Centric Data to Ensure Mission Success
UCore Semantic Layer: A Logically Enhanced (OWL) Version of the UCore
Taxonomy
Session 2
March 17, 2010
Delivering the Power of Net-Centric Data to Ensure Mission Success
Overview
• Overview of UCore 2.0 Taxonomy
• Overview of UCore SL
– UCore SL Taxonomy
– UCore SL Relations
– Equivalence Relations
– Disjointness Axioms
– Restriction Classes
Delivering the Power of Net-Centric Data to Ensure Mission Success
UCore 2.0 Taxonomy
• 55 classes
• Simple (OWL Lite) taxonomy
• Intentionally weak semantics
• Answers the “What” and the “Who” of UCore Messages
• Does not address the “When” and “Where” directly
• Adequate for indexing and metadata purposes
Delivering the Power of Net-Centric Data to Ensure Mission Success
Entity Branch
• 27 Classes
• Relatively flat taxonomy
Delivering the Power of Net-Centric Data to Ensure Mission Success
Event Branch
• 28 Classes
• Very flat taxonomy
Delivering the Power of Net-Centric Data to Ensure Mission Success
UCore 2.0 Taxonomy
Specifies where the term fits into the
taxonomy
Specifies where the term fits into the
taxonomy
Definition derived from the Oxford English
Dictionary
Definition derived from the Oxford English
Dictionary
• No relations• No rules / constraints• No disjointness axioms
• No relations• No rules / constraints• No disjointness axioms
NOTE: No label provided – i.e., no human friendly name.
http://ucore.gov/ucore/2.0/codespace#Person
NOTE: No label provided – i.e., no human friendly name.
http://ucore.gov/ucore/2.0/codespace#Person
Delivering the Power of Net-Centric Data to Ensure Mission Success
Additional (implicit) semantics contained in the XML schema
Additional (implicit) semantics contained in the XML schema
Delivering the Power of Net-Centric Data to Ensure Mission Success
Additional (implicit) semantics contained in the XML schema
Additional (implicit) semantics contained in the XML schema
Delivering the Power of Net-Centric Data to Ensure Mission Success
Summary
• UCore Taxonomy is a lightweight ontology
• Does not utilize OWL DL logical resources
• It is up to the user to understand the meaning of a UCore 2.0 term and apply it correctly
• No automated support to validate logical consistency of COI extensions
• When semantics matter use UCore SL
Delivering the Power of Net-Centric Data to Ensure Mission Success
UCore SL
• Developed in OWL DL 1.0 (Next release OWL 2?)
– beta version
– UCore SL 1.1 (minor fixes)
• 143 classes, 16 relations
• Equivalences between UCore SL classes and UCore classes (issue of mapping)
• Use of definitions in UCore SL
• OWL DL resources
– Disjointness axioms,
– OWL restrictions
– Domain and range declarations
Delivering the Power of Net-Centric Data to Ensure Mission Success
OWL DL 1.0
OWL DL is a
W3C Recommendation
One of three species: OWL Lite, OWL DL and OWL Full
Knowledge representation language for authoring ontologies
Revision of DAML+OIL (DARPA funded project)
Ontology Editors
Protégé OWL
TopBraid Composer
Knoodl
NeOn ToolKit
OntoStudio
Swoop
Standards BasedRDFS/OWL, SPARQL, RIF,
Delivering the Power of Net-Centric Data to Ensure Mission Success
UCore SL Taxonomy
• 155 Classes
• Logical Definition
• Equivalence Statements
• OWL Restriction Classes
• Disjointness Axioms
Delivering the Power of Net-Centric Data to Ensure Mission Success
UCore Equivalence Classes
Examples of equivalence statements
Examples of equivalence statements
Not all UCore SL classes have UCore
equivalents
Not all UCore SL classes have UCore
equivalentsA equivalent to B iff every instance of A is an instance of B.
A equivalent to B iff every instance of A is an instance of B.
Delivering the Power of Net-Centric Data to Ensure Mission Success
Disjointness Axioms
A B
empty
A disjoint with B iff no instance of A is an instance of B
Delivering the Power of Net-Centric Data to Ensure Mission Success
Logically speaking, UCore 2.0 is too weak to detect simple inconsistencies.
Using UCore SL as a supporting layer makes it possible to identify that something cannot be both a Person and an Organization
Chart by Barry Smith, Director, National Center for Ontological Research, [email protected].
Provides Additional Logical Resources
Delivering the Power of Net-Centric Data to Ensure Mission Success
OWL Restrictions
Property is subclass of the set of all things that inhere in some PhysicalEntity.
Property is subclass of the set of all things that inhere in some PhysicalEntity.
Delivering the Power of Net-Centric Data to Ensure Mission Success
OWL Restrictions
Person rdfs:subClassOf [
owl:onProperty :has;
owl:someValuesFrom :SocialSecurityNumber .
]
A B
A = The set of all people
B = The set of all things that have a Social Security Number
Delivering the Power of Net-Centric Data to Ensure Mission Success
OWL Restrictions
SocialSecurityNumber rdfs:subClassOf [
owl:onProperty :denotes;
owl:someValuesFrom :Person .
]
A B
A = The set of all Social Security Numbers
B = The set of all people
Delivering the Power of Net-Centric Data to Ensure Mission Success
UCore SL Relations
• 16 Relations
• Derived from UCore XML schema
• ?x agent_in ?y => ?x involved_in ?y
Delivering the Power of Net-Centric Data to Ensure Mission Success
UCore SL Relations
Most UCore SL Relations derived from the UCore XML Schema
Most UCore SL Relations derived from the UCore XML Schema
Delivering the Power of Net-Centric Data to Ensure Mission Success
UCore SL Relations
involved_in involved_in
AgentAgent EventEvent
rdfs:domain rdfs:range
Delivering the Power of Net-Centric Data to Ensure Mission Success
Note on Reasoning with Domain and Ranges
involved_ininvolved_in
XX
slr:involved_in
a owl:ObjectProperty ;
rdfs:domain sl:Agent ;
rdfs:range sl:Event .
Delivering the Power of Net-Centric Data to Ensure Mission Success
Why disjointness statements matter
involved_ininvolved_in
XX
This mistake is only caught if Agent and
SnowIceStorm are disjoint with one another
This mistake is only caught if Agent and
SnowIceStorm are disjoint with one another
Delivering the Power of Net-Centric Data to Ensure Mission Success
Properties
• Sex, Age, Height, Weight, etc.
• Diseases and Symptoms (biosurveillance)
Delivering the Power of Net-Centric Data to Ensure Mission Success
Additional (implicit) semantics contained in the XML schema
Additional (implicit) semantics contained in the XML schema
Delivering the Power of Net-Centric Data to Ensure Mission Success
Data Type Properties
Johann a :Person ;
:name “Johann”^^xsd:string ;
:age “42”^^xsd:integer ;
:height “73”^^xsd:double ;
:weight “210”^^xsd:double ;
:sex “1”^^xsd:string .
Delivering the Power of Net-Centric Data to Ensure Mission Success
More robust treatment of properties
Person Person Weight Weight
JohannJohann _:b01_:b01
rdf:typerdf:type rdf:typerdf:type
inheres_ininheres_in
“210”^^xsd:double“210”^^xsd:double
“95.2543”^^xsd:double“95.2543”^^xsd:double
“2001-10-26T21:32:52+02:00”^^xsd:dateTime“2001-10-26T21:32:52+02:00”^^xsd:dateTime
in_poundsin_pounds
in_kilosin_kilos
measured_onmeasured_on
Delivering the Power of Net-Centric Data to Ensure Mission Success
Information Content Entity
• Classify Identifiers, Codes, Names, etc.
• Classify Information
Delivering the Power of Net-Centric Data to Ensure Mission Success
Roles
Equipment Equipment CargoRole CargoRole
e-1e-1 cr-1cr-1
rdf:typerdf:type rdf:typerdf:type
inheres_ininheres_inholds_overholds_over
Time-1Time-1
Unclassified 30
End of Session 2
30
Delivering the Power of Net-Centric Data to Ensure Mission Success
Developing Ontologies with UCore SL
Session 5
March 17, 2010
Delivering the Power of Net-Centric Data to Ensure Mission Success
Overview
• How to extend UCore SL
• How to validate extensions of UCore SL
• How to represent temporal qualification of relations
Delivering the Power of Net-Centric Data to Ensure Mission Success
Two Strategies for Extending UCore SL
1. Import entire ontology
• Direct import mechanism
• Necessary to ensure consistent extension of UCore SL
2. Import selective resources from ontology
• MIREOT - Minimal information to reference external ontology terms (see http://obi-ontology.org/page/MIREOT )
• Selects only those resources from UCore SL that are relevant to a domain ontology
Delivering the Power of Net-Centric Data to Ensure Mission Success
owl:imports
owl:imports
a rdf:Property , owl:OntologyProperty ;
rdfs:label "imports" ;
rdfs:domain owl:Ontology ;
rdfs:range owl:Ontology .
owl:imports
a rdf:Property , owl:OntologyProperty ;
rdfs:label "imports" ;
rdfs:domain owl:Ontology ;
rdfs:range owl:Ontology .
The owl:imports annotation imports the contents of another OWL ontology into the current ontology.
The owl:imports annotation imports the contents of another OWL ontology into the current ontology.
Delivering the Power of Net-Centric Data to Ensure Mission Success
Example of owl:imports mechanism
<http://UCore-SL-Relations-OWL-DL><http://UCore-SL-Taxonomy-OWL-DL>
<http://ucore.gov/ucore/2.0/codespace>
<http://UCore-SL-OWL-DL>
owl:imports owl:imports
owl:imports
Delivering the Power of Net-Centric Data to Ensure Mission Success
Extending UCore SL
• How does an domain ontology extend UCore SL using the direct import mechanism?
– Import UCore SL directly into the domain ontologyPro: All UCore SL content is available for development
Con: All UCore SL content is available for development
– Import UCore SL and the domain ontology into a third ontologyPro: Separation of ontology content
Con: Difficult to reuse UCore SL terms (e.g. my:Person owl:equivalentClass sl:Person)
Delivering the Power of Net-Centric Data to Ensure Mission Success
Problems with Simple Import Strategy
• Direct OWL imports are not practical for day-to-day development.
• Avoid the overhead of importing the complete ontology from which the terms derive.
• Reuse existing ontology resources, therefore avoiding duplication of effort and ensuring orthogonality.
• Different resources may have been constructed using different design principles, which may not align. Importing such ontologies as a whole could lead to inconsistencies or unintended inferences.
<http://Common-Core-Ontology-OWL-DL>
<http://COI-Domain-Ontology-OWL-DL>
<http://UCore-SL-OWL-DL>
owl:imports
owl:imports
Delivering the Power of Net-Centric Data to Ensure Mission Success
MIREOT
• MIREOT - Minimum information to reference an external ontology terms
– The Ontology for Biomedical Investigations (OBI)
– OBI is being built under the Basic Formal Ontology (BFO)
– Membership in the OBO Foundry
Delivering the Power of Net-Centric Data to Ensure Mission Success
MIREOT
• Define the minimal information we need
– URI of the class
– URI of the source ontology
– Position in the target ontology
• => this minimal set allows to unambiguously identify a term
• Information stored in external.owl
Delivering the Power of Net-Centric Data to Ensure Mission Success
MIREOT
• Additional information
– Label
– Definition
– Other annotations
– OWL Restrictions etc.
• External information stored in externalDerived.owl
• Use external.owl to auto-generate externalDerived.owl
Delivering the Power of Net-Centric Data to Ensure Mission Success
MIREOT Architecture
Delivering the Power of Net-Centric Data to Ensure Mission Success
Example of MIREOT Methodology
Delivering the Power of Net-Centric Data to Ensure Mission Success
external.owl
Delivering the Power of Net-Centric Data to Ensure Mission Success
Generate externalDerived.owl
Delivering the Power of Net-Centric Data to Ensure Mission Success
externalDerived.owl
Delivering the Power of Net-Centric Data to Ensure Mission Success
COI Extension Revisited
Delivering the Power of Net-Centric Data to Ensure Mission Success
Updating
Delivering the Power of Net-Centric Data to Ensure Mission Success
MIREOT
• The MIREOT standard is a trade-off between complete consistency checking and heavyweight importing versus lightweight importing but partial consistency checking. We are aware of and accept that by copying only parts of an ontology there is the risk that inferences drawn may be incomplete or incorrect: correct inference using the external classes is only guaranteed if the full ontologies are imported.
Delivering the Power of Net-Centric Data to Ensure Mission Success
How to validate extensions of UCore SL
• Validate OWL species
• Validate Consistency
• Identify cases of multiple inheritance
• Containment
Delivering the Power of Net-Centric Data to Ensure Mission Success
Validate OWL Species
Delivering the Power of Net-Centric Data to Ensure Mission Success
Validate Consistency
• Run OWL DL reasoner to test consistency
• OWL DL Reasoners: Pellet, Fact ++, RacerPro
• Pellet can also operate upon an ontology written in the OWL Full dialect but only by ignoring those features of OWL Full which make it undecidable. Thus, any inconsistencies introduced by the use of those features would not be detected.
Delivering the Power of Net-Centric Data to Ensure Mission Success
Delivering the Power of Net-Centric Data to Ensure Mission Success
OWL Reasoners
Delivering the Power of Net-Centric Data to Ensure Mission Success
Identify cases of multiple inheritance
Use SPARQL queries to identify cases of multiple
inheritance
Use SPARQL queries to identify cases of multiple
inheritance
Delivering the Power of Net-Centric Data to Ensure Mission Success
Containment
• A domain ontology fully extends UCore SL if and only if every class in the domain ontology is an (improper) subclass of some class in UCore SL.
• Simply put, containment requires that the domain covered by a lower-level ontology be circumscribed by the domain covered by the higher-level ontology from which it extends.
Delivering the Power of Net-Centric Data to Ensure Mission Success
Containment
Use SPARQL queries to identify cases of where a domain ontology term is not subsumed under a
UCore SL term
Use SPARQL queries to identify cases of where a domain ontology term is not subsumed under a
UCore SL term
Delivering the Power of Net-Centric Data to Ensure Mission Success
Temporal Qualifications
Delivering the Power of Net-Centric Data to Ensure Mission Success
The Problem
• Wheel-1 cannot be part of Car-1 and Car-2 at the same time.
• Rim-1 cannot be part of Car-1 and Car-2 at the same time.
1) Rim_1 part_of Wheel_1
2) Wheel_1 part_of Car_1
3) Wheel_1 part_of Car_2
4) Car_1 ≠ Car_2
----------------
5) Rim_1 part_of Car_1
6) Rim_1 part_of Car_2
1) Rim_1 part_of Wheel_1
2) Wheel_1 part_of Car_1
3) Wheel_1 part_of Car_2
4) Car_1 ≠ Car_2
----------------
5) Rim_1 part_of Car_1
6) Rim_1 part_of Car_2
Delivering the Power of Net-Centric Data to Ensure Mission Success
A Solution: Reification
?statement a rdf:Statement ;
rdf:subject ex:Rim_1;
rdf:predicate slr:part_of ;
rdf:object ex:Wheel_1 .
?statement a rdf:Statement ;
rdf:subject ex:Rim_1;
rdf:predicate slr:part_of ;
rdf:object ex:Wheel_1 .
ex:Rim_1 slr:part_of ex:Wheel_1ex:Rim_1 slr:part_of ex:Wheel_1
Delivering the Power of Net-Centric Data to Ensure Mission Success
Reification
ex:holdsDuring
a owl:ObjectProject ;
rdfs:domain rdf:Statement ;
rdfs:range ex:TemporalInterval .
ex:holdsAt
a owl:ObjectProject ;
rdfs:domain rdf:Statement ;
rdfs:range ex:TemporalInstant .
ex:holdsDuring
a owl:ObjectProject ;
rdfs:domain rdf:Statement ;
rdfs:range ex:TemporalInterval .
ex:holdsAt
a owl:ObjectProject ;
rdfs:domain rdf:Statement ;
rdfs:range ex:TemporalInstant .
Delivering the Power of Net-Centric Data to Ensure Mission Success
Reification
?statement
a rdf:Statement ;
rdf:subject ex:Rim_1;
rdf:predicate slr:part_of ;
rdf:object ex:Wheel_1 ;
ex:holdsDuring ex:time_1 .
?statement
a rdf:Statement ;
rdf:subject ex:Rim_1;
rdf:predicate slr:part_of ;
rdf:object ex:Wheel_1 ;
ex:holdsDuring ex:time_1 .
ex:time_1
a ex:TemporalInterval
ex:hasBeginning “2008-03-15”^^xsd:date ;ex:hasEnd “2009-03-15”^^xsd:date .
ex:time_1
a ex:TemporalInterval
ex:hasBeginning “2008-03-15”^^xsd:date ;ex:hasEnd “2009-03-15”^^xsd:date .
Delivering the Power of Net-Centric Data to Ensure Mission Success
How to reason with part_of
All part_of triplesSubset of part_of
triples
Use SPARQL Query to select
subset of part_of triples to reason
over
1) Rim_1 part_of Wheel_1
2) Wheel_1 part_of Car_1
3) Wheel_1 part_of Car_2
----------------
4) Rim_1 part_of Car_1
5) Rim_1 part_of Car_2
1) Rim_1 part_of Wheel_1
2) Wheel_1 part_of Car_1
3) Wheel_1 part_of Car_2
----------------
4) Rim_1 part_of Car_1
5) Rim_1 part_of Car_2
Delivering the Power of Net-Centric Data to Ensure Mission Success
Problems with Reification
• Using rdf:Statement makes your ontology OWL Full– Store reified triples as instance data and not as part of your
ontology
– Use an OWL DL compliant method of reificationex:PartOf_1
a ex:PartOfState ;ex:arg_1 ex:Rim-1 ;ex:arg_2 slr:part_of ;ex:arg_3 ex:Wheel-1 ;ex:holdsDuring ex:time_1 .
– Does OWL 2 make this concern irrelevant?
• Reification results in too many triples
Unclassified 64
End of Session 5
64