Luis Bermudez Stephanie Watson

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

• add values to isPartOf
• add an existing region

• 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)

• combines OWL and RuleML
• proposed to standardize the expression of rules in OWL

• 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

• to convert CVs into a common language, OWL

• 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

• your topics
• web portal controlled vocabulary

• 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

• Robert Laurini INSA –Lyon

• http://lisi.insa-lyon.fr/~laurini

• TopBraid tutorial