ontology best practices: experiences with sweet
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Ontology Best Practices: Experiences with SWEET. Rob Raskin NASA/Jet Propulsion Laboratory Pasadena, CA. Why an Upper-Level Ontology for Earth System Science? Why cooperate?. Many common concepts used across Earth Science disciplines (e,g, Temperature, Pressure) - PowerPoint PPT PresentationTRANSCRIPT
Ontology Best Practices: Experiences with SWEET
Rob RaskinNASA/Jet Propulsion Laboratory
Pasadena, CA
Why an Upper-Level Ontology for Earth System Science?
Why cooperate?
Many common concepts used across Earth Science disciplines (e,g, Temperature, Pressure)
Provides common definitions for terms used in multiple disciplines or communities
Provides common language in support of community and multidisciplinary activities
Provides common “properties” (relations) for tool developers Reduced burden (and barrier to entry) on creators of
specialized domain ontologies Only need to create ontologies for incremental knowledge
Role of Upper Level Earth Science Ontology
Math Physics Chemistry
Space
TimeProperty
PlanetaryRealmProcess, Phenomena
SubstanceData
StratosphericChemistry
Biogeochemistry Specialized domains
import
import
Common Earth elements
General domains
Semantic Web for Earth and Environmental Terminology (SWEET)
Concept space written in OWL Initial focus to assist search for data resources
Funded by NASA Later focus to serve as community standard Enables scalable classification of Earth system science
concepts Populated initially with GCMD, CF concepts (decomposed)
Non-LivingSubstances
LivingSubstances
PhysicalProcesses
Earth Realm
PhysicalProperties
Time
NaturalPhenomena
Human Activities
Integrative Ontologies
Space
Data
SWEET 1.0 Ontologies (and their interrelationships)
Faceted Ontologies
Units
Numerics
SWEET 2.0 Same facets, but organized by subject 12 ontologies --> 100 ontologies Easier for domain specialists to build
self-contained specialized ontologies that extend existing ones
SWEET 2.0Ontologies
Importationt
Common Issues Units
UDUnits Standard math
Ordered pairs and triples, arithmetic operations Intervals
hasLowerBound, hasUpperBound, hasUnit Provenance
Sequence of steps Fuzzy concepts
nearlySameAs, similarityMeasure [0…1]
Best Practices (1): Identify characteristic level of abstraction of
each term If multiple definitions/levels (e.g., “climate”), repeat
in multiple ontologies (namespaces) Keep ontologies small, modular
Be careful that “Owl:Import” imports everything Use higher level ontologies where possible
Identify hierarchy of concept spaces Try to keep dependencies unidirectional
Best Practices (2):
For synonyms, identify (community, preferred term) pairs
Gain community buy-in Involve respected leaders
Most ontologies can be faceted Holistic ontologies can be layers/wrappers atop
faceted ontologies
Best Practices (3):
Use OWL individuals (instances) sparingly Assume OWL-DL will be used, because most tools
cannot support OWL-Full Typically, a data collection is a “class” and a component
of the Earth is a class A particular observation at a specific time is a “state” (of
the planet) which could be an individual OWL has limited capabilities
Instructions to reasoners can be included (e.g., “multiply”) Collect suggestions for implementations in future
versions, or an OWL-Sci package
Community Issues
Review Board Who will oversee and maintain for perpetuity (or at least through the
next funding cycle) ESSI? Content
Maintain alignment given expansion of classes and properties No removal of terms except for spelling or factual errors Subscription service to notify affected ontologies when changes made Must avoid contradictions Additions can create redundancy if sameAs not used Humans must oversee “matching” CF has established moderator to carry out analogous additions
PlanetOnt.orgCollaboration Web Site
Discussion tools Blog, wiki, moderated discussion board
Version Control/ Configuration Management Trace dependencies on external ontologies Tools to search for existing concepts in registered
ontologies Ontology Validation Procedure
W3C note is formal submission method Registry/discovery of ontologies Support workflows/services for ontology development
PlanetOnt.org
ESIP Federation
PO.DAAC Knowledge Bases
PeopleDocuments
Data Products
MetadataTools/
Services
Roles/Tasks
ScienceConcepts
Missions
Applications
Instruments
Web Pages
DataProcessing
Organiza-tions
Announce-ments
Inquiries Computers
Public access
Resources SWEET
http://sweet.jpl.nasa.gov Ontology development/sharing site
http://PlanetOnt.org Noesis (search tool)
http://noesis.itsc.uah.edu SESDI
http://sesdi.hao.ucar.edu