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IRI Data Library Faceted Search : an example of

IRI Data Library Faceted Search : an example of. RDF-based faceted search for climate data Drawing on multiple ontologies to build an application Using inference to connect ontologies describing different parts of the framework http://iridl.ldeo.columbia.edu/ontologies/. Faceted Search.

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IRI Data Library Faceted Search : an example of

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  1. IRI Data Library Faceted Search: an example of • RDF-based faceted search for climate data • Drawing on multiple ontologies to build an application • Using inference to connect ontologies describing different parts of the framework http://iridl.ldeo.columbia.edu/ontologies/

  2. Faceted Search http://iridl.ldeo.columbia.edu/ontologies/query2.pl?...

  3. Distinctive Features of the search • Search terms are interrelated • terms that describe the set of returns are displayed (spanning and not) • Returned items also have structure (sub-items and superseded items are not shown)

  4. Architectural Features of the search • Interface is generated from a set of Terms connected to a set of Items • Multiple search structures possible • Multiple languages possible • Search structure is kept in the database, not in the code http://iridl.ldeo.columbia.edu/ontologies/query2.pl

  5. Search Interface as Multiple Ontologies Additional Semantics Dataset Ontology Search Ontology Datasets Search Interface Users

  6. Ontology Types • Attribute Ontology (e.g. Dataset) • Object Ontology (essential for crosswalk) • Term Ontology (e.g. search ontology)

  7. Attribute Ontology • Subjects are the only type-object • Predicates are “attributes” • Objects are datatype • Isomorphic to simple data tables • Isomorphic to netcdf attributes of datasets • Some faceted browsers: predicate = facet

  8. Object Ontology • Objects are object-type • Isomorphic to “belongs to” • Isomorphic to multiple data tables connected by keys • Express the concept behind netcdf attributes which name variables • Concepts as objects can be cross-walked • Concepts as object can be interrelated

  9. Example: controlled vocabulary {variable} cfatt:standard_name {“string”} Where string has to belong to a list of possibilities. {variable} cfobj:standard_name {stdnam} Where stdnam is an individual of the class cfobj:StandardName

  10. Example: controlled vocabulary Bi-direction crosswalk between the two is somewhat trivial, which means all my objects will have both cfatt:standard_name and cfobj:standard_name

  11. Example: controlled vocabulary If I am writing software to read/write netcdf files, I use the cfatt ontology and in particular cfatt:standard_name If I am making connections/cross-walks to other variable naming standards, I use cfobj:standard_name

  12. Term Ontology Concepts as individuals Simple Knowledge Organization System (SKOS) is a prime example The ontology used here is slightly different than SKOS: facets are classes of terms rather than being top_concepts

  13. Nuanced tagging Concepts as objects can be interrelated: specific terms imply broader terms Object ends up being tagging with terms ranging from general to specific. Search can then be nuanced tagging can proceed in absence of perfect information

  14. Faceted Search Explicated

  15. Search Interface • Items (datasets/maps) • Terms • Facets • Taxa

  16. Search Interface Semantic API {item} dc:title dc:description rss:link iridl:icon dcterm:isPartOf {item2} dcterm:isReplacedBy {item2} {item} trm:isDescribedBy {term} {term} a {facet} of {taxa} of {trm:Term}, {facet} a {trm:Facet}, {taxa} a {trm:Taxa}, {term} trm:directlyImplies {term2}

  17. Faceted Search w/Queries http://iridl.ldeo.columbia.edu/ontologies/query2.pl?...

  18. queries queries queries RDF RDF RDF RDF RDF RDF RDF RDF RDF RDF RDF RDF RDF RDF RDF RDF RDF Architecture Virtual (derived) RDF

  19. IRI RDF Architecture Data Servers MMI Ontologies JPL bibliography Start Point Standards Organizations RDF Crawler Location Canonicalizer RDFS Semantics Owl Semantics SWRL Rules SeRQL CONSTRUCT Time Canonicalizer Sesame Search Queries Search Interface

  20. Cast of Characters NC – netcdf data file format CF – Climate and Forecast metadata convention for netcdf SWEET - Semantic Web for Earth and Environmental Terminology (OWL Ontology) IRIDL – IRI Data Library

  21. CF attributes NC basic attributes IRIDL attributes/objects CF data objects CF Standard Names (RDF object) SWEET Ontologies (OWL) Location CF Standard Names As Terms IRIDL Terms SWEET as Terms Search Terms Gazetteer Terms

  22. See Also • http://iridl.ldeo.columbia.edu/ontologies/ • http://iri.columbia.edu/~benno/Talks/AGU2007Poster.pdf

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