Luis Bermudez Stephanie Watson



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tarix30.12.2017
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Coastal Atlas Interoperability - Ontologies (Advanced topics that we did not get to in detail)

  • Luis Bermudez

  • Stephanie Watson

  • Marine Metadata Interoperability Initiative


Overview

  • Goals

  • Introduction to Ontologies

  • Ontology Components and Practical Exercise

  • Advanced Ontology Concepts

    • Mappings
    • Restrictions and Description Logic
    • SPARQL and Rules
  • MMI Tools

  • Ontology Engineering

  • Interoperability Demonstration

  • Discussions



Mapping ala SKOS



SKOS

  • provides a standardized way of representing KOS, such as thesauri, classification schemes, and taxonomies

  • uses RDF

    • RDF vocabularies:
      • SKOS Core (for describing KOS)
      • SKOS Mapping (for mapping between concepts - broad, narrow, exact match)
      • SKOS Extensions


Mapping ala SKOS

  • import skos.owl

  • it defines 3 convenient properties to relate instances



Import the 2 atlas ontologies that were created by the 2 groups



  • Make relations between your aX.owl file and one of the atlas files

    • select one of your favorite topics in your aX.owl file and create an skos:relation (broad, narrow, exact match) to a topic from one of the atlases.
  • Need to add the skos:property in the Resource Form



Adding SKOS Property(ies) in Resource Form



  • Commit to SVN - check the web site to make sure your file is there

  • Meanwhile, atlas experts - make SKOS type mappings among the terms in your atlases



Categorization by properties or the world of restrictions or defining classes using Description Logics (DL)



Story...

  • Facts:

  • We are in 2010...

  • SuperAtlas is a super ontology for atlas features. It was signed in 2009 in Monterey by 103 web atlas representatives.

  • Each group is now an atlas and will have 4 SuperAtlas Features available in the next 20 minutes.



Steps

  • We will define categories as allowed in OWL-DL.

  • The definitions of the categories are based on the SuperAtlas Ontology, which is the common vocabulary.

  • We will run the inferencer, which will automatically categorize your instances.



SuperAtlas Ontology



Process

  • Import SuperAtlas Ontology

  • Create a class “PersonRecreationalFeature” which is a sub (or sub-sub) class of your:PersonConcept

  • make it subclass of superatlas:RecreationalFeature



Create features (e.g. places that could appear in an atlas)



Add Facts about Those Features:

  • Relative location

  • Activities that can occur

    • add an Activity
    • create/add new instance


You should have 4 instances similar to these:

  • You should have 4 instances similar to these:



Defining Classes using Description Logics

  • Defining Classes using Description Logics



Defining a Class in OWL DL

  • Example: Define EuropeanRegion

    • = All regions that are part of Europe.
    • More formally:


Equivalent Restrictions



Subclass Restrictions



Restriction Keywords



Restriction Keywords (cont.)



Complex Expressions



Restrictions Exercise



BREAK 10:30-10:45



SPARQL AND RULES



SPARQL

  • Query language for RDF (similar to SQL)

  • Think - triple triple triple



SPARQL Examples

  • PREFIX table: <http://www.daml.org/2003/01/periodictable/PeriodicTable#>

  • SELECT ?name ?symbol ?number ?color

  • FROM <http://www.daml.org/2003/01/periodictable/PeriodicTable.owl>

  • WHERE

  • {

  • ?element table:name ?name.

  • ?element table:symbol ?symbol.

  • ?element table:atomicNumber ?number.

  • OPTIONAL { ?element table:color ?color. }

  • }



Examples

  • Find all the subclasses of superatlas:Feature



Create your own queries

  • ...



Using Rules

  • OWL is limited in expressiveness.

    • can’t combine properties (e.g., uncle is a composition of brother and parent)
    • can’t use computed values or arithmetic comparisons (e.g., stating that a teenager is a person with age between 13 and 19)
  • Semantic Web Rule Language (SWRL)

  • Open ontology and view rules



Rules

  • Rule is simple: If A then B or A -> B

  • Semantic Web Rule Language (SWRL)

  • swrl:body -> swrl:head

  • or

  • using JENA rules - very similar syntax



Create Rules

  • ensure your ontology imports these namespaces:

    • http://www.daml.org/rules/proposal/swrlb.owl
    • http://www.daml.org/rules/proposal/swrl.owl
  • SWRL rules are instances of swrl:Imp and can be created by:

    • Select swrl:Imp, edit body and head. e.g., to formalize the rule that says...
      • (?a hasChild ?c) for swrl:body
      • Parent (?a) for swrl: head


Rules Exercise

  • Import jena.owl



Configure Inferencing



Example

  • Create a rule to infer all american sports

  • Create a class under WebCategories and add a jena:Rule property (drag it)

    • e.g. AmericanSports


MMI Tools

  • VOC2OWL

  • VINE

    • to map between CVs/ontologies represented in OWL
  • SEMOR

    • matches your search term to terms from other controlled vocabularies to find data and information








Engineering Lifecycle



What we did ....

  • Controlled Vocabularies

  • Mappings

    • among your topics and the FOAF one
    • among atlas and upper atlas ontology
  • Categories

    • Infer hierarchies
  • Knowledge of a Domain

    • Formal definition of classes
    • Rules expression
  • MMI Tools

  • Ontology Engineering



Slides acknowledgments




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