1. Lifecycle Metadata for Digital Objects
November 6, 2006
Descriptive Metadata:
“Modeling the World”

2. Descriptive metadata for what?
WWW: now seen as the ONE place to find everything
Descriptive metadata provides:
Unique identification for a resource
Information permitting evaluation/selection of a resource
Information describing all “essential properties”

3. WWW: How to find things What does search mean on the WWW?
How to support its multiple purposes?
Failure of search engines to render precise results (problems of scale; is this true?)
Failure of HTML metatags (spamming)
Solution
local expert cataloging (providing access points)
making local cataloging available
remote free-text searching (inferring access points)
Dublin Core and its limitations
Warwick Framework and RDF
Universal Semantic Web

4. Some metadata examples
Individual objects (Dublin Core and its derivatives)
Multimedia and/or complex objects (METS/MPEG21)
Books and other chunks of information (MARC)
Finding aids (EAD)

5. Semantic Web
Berners-Lee’s vision for the Web: basically machine-understandable metadata about meaning for everything on the Web

6. Aside on cataloging
Cataloging systems as relatively static: relationships remained tacit and externally specified
Classification systems
Controlled vocabularies
Name authorities
Note all of these can be represented in XML as specific namespaces (MARC, MODS, etc.)
New methods aren’t that different: ontologies for the Semantic Web are also namespaces--but ones that are much more specific about actions

7. Ontologies
Like previous classification systems, they are being built by hand
General (Cyc) and domain-specific (especially for B to B, web services)
Ontologies establish a joint terminology between members of a community of interest
Ontologies specify domain knowledge in terms of formal logic that includes actions by and among entities
Ontologies will be used to guide extraction of semantic content from texts (and perhaps automatic generation of metadata)

8. Topic Maps
Representation of information using topics, associations, and occurrences
Note how this “triples” representation fits well with RDF (entity, relationship, entity)
An XML representation: XTM
An (older) ISO standard: ISO/IEC 13250:2003
Related to ontologies and mind maps; designed to “map” semantic regions

9. Web Services
How to provide processing services over the WWW: XML and HTTP infrastructure passing remote procedure calls
UDDI (Universal Description Discovery and Information) is the registry of services
WSDL (Web Services Description Language) allows “advertisement” of services (in XML, of course) in the UDDI registry
SOAP (Simple Object Access Protocol) is the XML wrapper for requests sent to services
Example: DC metadata registry:

10. Does what we know fit into this?
DC and derivatives are aimed at the single object (though not always used for it) and are frequently used in WWW contexts (cf. Warwick Framework ≈ RDF namespaces)
EAD describes descriptions of aggregate chunks of information (chunked in terms of “series” or “collections”) but can describe single objects
MARC/MODS describes aggregate chunks of information (chunked in the form of “books”)
METS and MPEG21 are frames for multiple and multimedia objects

11. Granularity
Granularity governs the level at which metadata can be descriptive
Metadata granularity tends to be finer for digital objects
Digital objects cannot be managed without individual granularity (thank you David Bearman)

12. EAD: Describing descriptions
What is a finding aid?
Describing a finding aid so it can be searched
Expanding a finding aid to accommodate individual granularity
Is it efficient to drill down through a finding aid to individual objects?
Can EAD be searched from the bottom up?

13. EAD Schizophrenia
Because it describes finding aids, it has retained concern with look and feel
Mixes granular conceptual description with box/folder lists for physical (and contingent) object arrangements
Lack of granularity is expressed in the possibility of writing narrative with <p> tags everywhere

14. MARC: Chunked packages
International Standard Bibliographic Description (ISBD) as parent of MARC, TEI
MODS: User-friendly MARC? subset of MARC elements (20), language-based tags
MARC as descriptive metadata
Bibliographical detail for the work
Bibliographical detail for the specific instance of the work (cf. FRBR)
Places the work within one or many classificatory systems (ontologies, controlled vocabularies, authority lists)
But alas! Not consistent!

15. METS: Multimedia/Multiversion
METS developed to express “archival bond” among objects related to one another as a single work (cf. FRBR, Warwick Framework, RDF)
Reflects concerns of digital librarians who want to make a wide range of versions available
Standard form:
General descriptive metadata for package
Object link
Object type
Specific descriptive metadata set(s) for specific kinds of objects

16. What about the single object?
Is Dublin Core enough? Outdated? (15 elements)
What about derivatives?
Qualified DC, DC profiles
Australian elements (20)
Why describe the single object?
Who will describe at the object level?
Zillions of archivists?
Authors?
Automatic analysis (ontology-driven)?

17. Wisdom of Crowds vs Long Tail
The wisdom of crowds: tagging as democratized subject catalogin
The long tail: specialist cataloging for small niche groups, now visible online