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Making Metadata Work for the NSDL

The narrative of the NSDL's metadata initiative reflects a journey starting from a simple prototype in September 2001 to a robust metadata repository by December 2002, hosting over 250,000 records. This transformation included the adoption of the Dublin Core standard, exploration of OAI interoperability, and development of a user-friendly interface. The project faced various challenges, including the need for improved metadata quality, evolving standards, and user education. Looking ahead, NSDL aims to enhance its services and integrate new information while refining data evaluation techniques.

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Making Metadata Work for the NSDL

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  1. Making Metadata Work for the NSDL

  2. Starting from Sept. 2001 with ... • A prototype with not much behind it that was re-usable (http://siteforscience.org) • Lots of good ideas based on that prototype • An Oracle license • A very small group of people with many different visions of what we were doing • The management structure of a research project (e.g., none)

  3. ... jump to Dec. 2, 2002, when you will see (http://nsdl.org): • A Metadata Repository with roughly 250,000 metadata records (items and collections) • A uPortal-based user interface, containing: • a search service • a simple topic browse of collections • featured collection exhibits • views of future enhancements • A developing plan for the future

  4. Getting from there to here • Designing the Metadata Repository • Working with unfinished standards • Dublin Core in transition • XML schema for qualified DC in early stages • OAI 2.0 not yet cooked • Concerns from partners and funders around quality issues • Envisioning Simple Metadata-Based Services (SiMBaS)

  5. The Metadata Repository • Designed to scale • Based on an automated harvest/expose model with OAI at each end • A notion of “normalized metadata” with qualified Dublin Core as its base • Transformations on the way in, native and transformed re-exposed

  6. Standards at the bleeding edge • Metadata strategy based on crosswalking from 8 formats to one (NSDL-DC) • The reality: a Baskin-Robbins model of “standard metadata” • Standards badly documented, little organized support, very little training available at any price • Projects not obligated to offer metadata, even if they had it (in whatever form)

  7. OAI in transition—the story in 2002 • Version 1.1 was not yet widely used • Version 2 not yet available; NSDL became beta-tester (!) • Final version of OAI 2.0 delayed by NSDL needs (definition of change) • Now working with collection partners to bring up servers, ensure validation • Lower end option for OAI on the way

  8. The DC schema wars • DC-Architecture group working primarily on RDF schema • Gang of Five began work outside DC, presented version for comment to DC-Architecture Oct. 2002 • Process of approval not yet complete, NSDL using “final” version

  9. A few schema issues ... • Three namespaces • Restricted to “simple literal” values • Refinements expressed as elements • Encoding schemes expressed as new complexTypes (schemes not limited to a single element) • NSDL Schema types: • NSDL-DC • NSDL-Search • NSDL-All

  10. The Process • Data harvesting • Data evaluation • Transform specification • DB_insert file creation • Database ingest • OAI re-exposure

  11. Data evaluation • XML validity • DC conformance (whether simple or qualified) • Emphasis on Date, Type, Format, Identifier • Potential problem areas: • Special characters • “funky text” • Tools: XML Spy, Spotfire

  12. Specifying transform • Simple transforms (DC simple—>DC qualified) • Scheme identification for standard values (date, type, format, language) • Quality transforms • improving functionality of search limits by ensuring appropriate values for type and format • improving user experience by deleting funky text and special characters that affect display

  13. DB_Insert file • Header • First harvest? • Category (item, collection, annotation ...) • Harvest date • Source • Link to “native” metadata

  14. OAI exposure • OAI “About” • OAI “Provenance” • Metadata origin and rights assertions • Alterations to originally harvested data • Re-harvest information • Collection (& brand) association

  15. Still to do ... • Currently running on “manual” • Ingest process not yet completed or documented • data validation routines • additional metadata types (annotation) and services linked to metadata

  16. Automation opportunities • Collection registration • assignment of unique identities • “responsible entities” • harvest/re-harvest, transform/re-transform, and associated record keeping • integrating/linking new information with metadata record (service model)

  17. Other challenges • Educating data providers and aggregators about GOOD METADATA • Better techniques for evaluation and transformation • Coping with users? (Uh, oh)

  18. For more information • The NSDL Metadata Primer (http://metamanagement.comm.nsdlib.org/outline.html) • NSDL XML schema (http://ns.nsdl.org/schemas/nsdl_dc/nsdl_dc_v1.00.xsd)

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