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 Definition derived from the Oxford English Dictionary No relations No rules / constraints No disjointness axioms NOTE: No label provided – i.e., no human friendly name.

Delivering the Power of Net-Centric Data to Ensure Mission Success 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

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 Based RDFS/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 Not all UCore SL classes have UCore equivalents 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 AB 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, 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.

Delivering the Power of Net-Centric Data to Ensure Mission Success OWL Restrictions Person rdfs:subClassOf [ owl:onProperty :has; owl:someValuesFrom :SocialSecurityNumber. ] AB 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. ] AB 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

Delivering the Power of Net-Centric Data to Ensure Mission Success UCore SL Relations involved_in AgentEvent rdfs:domainrdfs:range

Delivering the Power of Net-Centric Data to Ensure Mission Success Note on Reasoning with Domain and Ranges involved_in X 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_in X 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

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 Weight Johann_:b01 rdf:type inheres_in “210”^^xsd:double “ ”^^xsd:double “ T21:32:52+02:00”^^xsd:dateTime in_pounds in_kilos measured_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 CargoRole e-1cr-1 rdf:type inheres_in holds_over Time-1

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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 ) 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 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.

Delivering the Power of Net-Centric Data to Ensure Mission Success Example of owl:imports mechanism 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 ontology Pro: 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 ontology Pro: 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. 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

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

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

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_ ) 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. ex:Rim_1 slr:part_of ex:Wheel_1

Delivering the Power of Net-Centric Data to Ensure Mission Success Reification ex:holdsDuring aowl:ObjectProject ; rdfs:domain rdf:Statement ; rdfs:range ex:TemporalInterval. ex:holdsAt aowl: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. ex:time_1 aex:TemporalInterval ex:hasBeginning “ ”^^xsd:date ; ex:hasEnd “ ”^^xsd:date.

Delivering the Power of Net-Centric Data to Ensure Mission Success How to reason with part_of All part_of triples Subset 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_ ) 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 reification ex:PartOf_1 aex: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

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