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Why are Ontologies Why are Ontologies Important ?Important ?

Luis Bermudez

QARTOD IIINovember 2-4, 2005

Ontology-Philosophy

“ Most fundamental branch of

metaphysics. It studies being or

existence as well as the basic

categories thereof—trying to find out

what entities and what types of

entities exist. ”

- Wikipedia

“ Because any ontology is, among other things, a social / cultural artifact, there is no purely objective perspective from which to observe the whole terrain of concepts. Instead of asking, “what hierarchical representation of concepts best captures the universal relationships among general ideas,” it is more productive to ask “what specific purpose do we have in mind for this conceptual map of entities and what practical difference will this ontology make? ”

-Wittgenstein, Tractatus Logico-Philosophicus.

SWEET Ontologieshttp://sweet.jpl.nasa.gov/ontology/

• Earth Realms

• Physical Phenomena

• Physical Processes

• Physical Properties

• Physical Substances

• Sun Realms

• Biosphere

• Data• Data Centers • Human Activities • Material Things • Numerics • Sensors• Space • Time • Units

Ontologies - Computer ScienceSpecification of conceptualizations

Body of Water Class

RiverLake

Has water

Is inland body

Has a relative defined channel

Lake RiverExample:1. Properties of real

world objects are identified.

2. Similarities are identified.

3. Concepts are created

4. and are expressed as a class.

5. Classes are related.

Subclass

Hydrologic Unit

Region Subregion Accounting Unit

Cataloging Unit

Is part of

Mid Atlantic

Delaware

Lower Delaware Schuylkill

Is part of

Is part of

Is part of

Subclasses

Is Transitive

Infer isPartOf

ClassLooks like a Real world objects

Instances

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…

Deborah McGuinness

Why Ontologies

• To share common understanding of the structure of information among people or software agents

• To enable reuse of domain knowledge• To make domain assumptions explicit• To separate domain knowledge from the

operational knowledge• To analyze domain knowledge

Cartic Ramakrishnan LSDIS Lab, University of Georgia

Why do we have a presentation about ontologies

in a QARTOD meeting ?

Do we need to share explictly QARTOD concepts ?

• Quality Levels• Flags• Sensors• Instrument Methodology• Calibration procedures• QC software procedures• Methods of verification and validation• Methods for manual checking• Malfunctions

WHP CTD data quality codes

WMO IGOSS observation quality codes

Can we state this explictly ?

MMI and ontologies

Semantic Issues

Search for seatemperature

dataSea surface Temperature

sea_water_temperature

TEMP

BODC

GCMD

CF

Don’t sure what data will get retrieved ?

Ocean Temperature

GCMD

Solving semantic issues

Harmonization

DTDDTD

Comma Comma Separated Separated

ValuesValues

HTMLHTML

Tab Tab Separated Separated

ValuesValues

Relational Relational DatabaseDatabase

XML/XSDXML/XSD

RDFRDF

OWLOWL

Web Ontology Language: OWL

<owl:Class rdf:ID=“Body_of_Water”></owl:Class>

<owl:Class rdf:ID=“River”> <rdfs:subClassOf rdf:resource=“# Body_of_Water”/></owl:Class>

• W3C Recommendation 02/04.• Based on RDF. (-> URI )• Inference capabilities.• Restriction of inherit properties.• Can be used to express

specifications and vocabularies

Body of Water

River

Domain Ontologies Repository

VOC2OWL

VINE Vocabulary Integration Environment

Community role

Topic Direct

mappings Inferred mappings

Total mappings

Plant Pigments 405 1,022 1,427

PaCOOS 131 375 506

Waves 93 181 274

Currents 90 153 243

CTD 81 432 513

Habitats 23 37 60

Total 823 2,200 3,023

Mapping Results

http://marinemetadata.org

Data Source

Data Provider Data User

gets

processes:formats/archives

publishesgets

processes: uses/analyzes

sendsgets

processes: formats/archives

sends

Ingests from instruments

<<MMIMMI /> />

About MMI• MMI = Marine Metadata Interoperability Initiative.• NSF funded and SURA (Southeastern Universities Research

Association) supported.• Initially one year project (September 2005). In the process of

getting extended (NOAA and NSF).• Organization; Executive committee (5), Steering committee (17),

technical committee(~25), and contributors. Community of more than 200 members

(October 2005). • Deliverables:

– Community web site with metadata content, guidance– Interoperability Demonstrations– Workshop: “Advancing Domain Vocabularies”– Tools : VINE Voc2OWL, Tethys, Web Services

http://marinemetadata.org/tethys

1. Implement two methods and make them

available using SOAP web services.

2. Convert the parameters, sources, and units

used in their system to an ontology.

(tool VOC2OWL ascii to OWL)

3. Map the terms used in the system to the MMI

preferred ontology: Standard vocabulary for

discovery (GCMD) and for usage (CF).

Steering Committee Members

• Robert Arko, LDEO

• Julie Bosch, NOAA

• Francisco Chavez, MBARI

• Ben Domenico, Unidata

• Karen Stocks, SDSC

• Steve Hankin, NOAA - Ocean.US/DMAC

• Roy Lowry, BODC • Mark Musen, Stanford Univ

• Michael Parke, Univ of Hawaii

• Lola Olsen, NASA Goddard

• Dawn Wright, Oregon State Univ

• Bob Weller, WHOI

• John Graybeal, MBARI. PI. (ExecComm) graybeal@mbari.org• Stephanie Watson, CeNCOOS. (ExecComm) swatson@mbari.org• Philip Bogden, SURA/SCOOP. (ExecComm) bogden@gomoos.org• Stephen Miller, Scripps. (ExecComm) spmiller@ucsd.edu

• National Science Foundation1

• SURA, the Southeastern Universities Research Association (http://www.sura.org),

• NOAA (including the Coastal Services Center),• ONR, the Office of Naval Research

(http://www.onr.navy.mil),• OceanUS and regional IOOS systems.

1 NSF Grant ATM-0447031

Credits

Thank you !

bermudez@mbari.org

ask@marinemetadata.org