Presentation on theme: "Using SKOS in practice, with examples from the classification domain Antoine Isaac Aida Slavic UDC Seminar 2009."— Presentation transcript:
Using SKOS in practice, with examples from the classification domain Antoine Isaac Aida Slavic UDC Seminar 2009
SKOS Simple Knowledge Organization System SKOS is a model to represent KOSs on in RDF in a simple way –Not aimed at fitting everything! –Not aimed at replacing existing (non-web) formats! Now an official W3C recommendation
SKOS basis SKOS offers a vocabulary for Concepts and concept schemes Labels Semantic relations Notes
Networking controlled vocabularies in SKOS Matching properties as conceptual relations KOS1 animals cats wildcats KOS2 animal human object
The relevance of networked KOSs Johan Stapel, Koninklijke Bibliotheek, Den Haag
Pointers to SKOS deployments SKOS implementation report Library of Congress Subject Headings lcsh.info RAMEAU subject headings stitch.cs.vu.nl/rameau DDC dewey.info
SKOS conversion example: NBC Dutch Basic Classification Sculpture: general Techniques and materials
Representing classes as concepts Techniques and materials
Relationships between classes Sculpture: general Techniques and materials
Issues with SKOS representation of classifications Captions and labels Languages Time versions of classes Coordination of classes Auxiliary elements …
Issue 1: notations, captions and labels SKOS enables representing notations And human-readable preferred (or alternative) labels, suited for captions Techniques and materials
Different choices for notations? Can notations be SKOS preferred labels? –They make sense for users & can be displayed We can represent them as language-neutral labels Several choices!
Issue 2: Multiple languages SKOS concepts can have labels in various languages
Issue 2: Multiple languages On dewey.info: one concept per class & language Several choices!
Issue 2: Multiple languages Introducing an abstract entity that denotes the time/language-independent class Using Dublin Core's isVersionOf link In RDF, it is possible to use other models in combination with SKOS…
Raising difficult issues: what is a "concept"? An artifact –used in descriptions, e.g., as subjects –used as a cluster for different labels with a similar meaning –in semantic relationships with other concepts basis for Knowlegde Organization Systems What qualifies as a concept for DDC? For UDC? Can different choices be done?
Issue 3: Tracking modifications 2RELIGION. FAITHS 21/28 CHRISTIANITY 21Natural theology. Theodicy. De Deo 22The Bible. Holy scripture 23Dogmatic theology 24Practical theology 25Pastoral theology 26Christian church in general 27General history of the Christian church 28Christian churches, sects 29NON CHRISTIAN RELIGIONS NOW RELIGION. FAITHS 21Prehistoric and primitive religions 22Religions of the Far East 23Religions of the Indian subcontinent 24Buddhism 25Religions of antiquity 26Judaism 27Christianity 28Islam 29Modern spiritual movements
Creating representations of the versions Each time-specific version should be a skos:Concept because: They are related to other (versions of) classes Classification act refers to a time-specific version A book on the Bible would be wrongly classified by "22" if "22" is the notation for "Far Eastern Religions"
IF WE FOCUS ON NOTATION Representing versions of classes Using Dublin Core's isReplacedBy link
Notations as a reference
Notations as aggregations Notations can be seen as hubs for time-specific version of classes Using the aggregates link from Object Reuse & Exchange (ORE) initiative
Tracking "Far East religions" in UDC database CLASS ID: NOTATION: 22 DESCRIPTION:Religions originating in the Far East *REPLACES: DESCRIPTION: Religion of Oriental peoples ID: NOTATION HISTORY : YES OLD DESCRIPTION: Bible There is interesting history information (incl. IDs) in the vocabulary management system!
Concepts across notations "Far East religions" existed before: It does not belong to 22 alone There is a more abstract Far East Religion entity –its conceptual content may be updated while it keeps its position in the hierarchy –it might be moved in the notation hierarchy and retain its conceptual content
Representing concepts across notations
Towards stable abstract concepts?
Two different versioning & aggregation mechanisms at work
Conclusion SKOS is an interoperability enabler There are still issues Different conversions reveal different choices But that's not a new problem, really Standardization often needs best practices & use cases Now, it is easier to publish and compare data As data is (will be) linked, it is even crucial to do it! Interaction between information experts and techies is crucial
Thank you! Questions? Drawing inspiration from Joseph Tennis & Stuart Sutton Michael Panzer Jakob Voss