1 CS 502: Computing Methods for Digital Libraries Lecture 18 Descriptive Metadata: Metadata Models

2 Administration

3 Metadata Models Challenge Are there general principles of metadata? Applicable to wide varieties of formats, genres and types. Useful for information discovery, collection management, preservation, e-commerce. Applicable to different creations, versions, etc. Balance cost against utility

4 Perceived Problems with Dublin Core Separate metadata elements for Creator, Contributor, and Publisher. Confusion between Genre and Format. Many qualifiers have been proposed for Date. Apparent redundancy of the element "Source". Reasons for the 1:1 relationship between metadata and an information resource.

5 Creations Work Expression Manifestation Item IsRealizedThrough IsEmbodiedIn IsExemplifiedBy

6 Agents WorkExpressionManifestation Item Corporate body Person Agent or IsCreatedBy IsRealizedBy IsProducedBy IsOwnedBy

7 Actions WorkExpressionManifestation Item Agent Actions PlaysRoleIn Transforms

8 Actions Originate Compile Excerpt Reformat Use Acquire/relinquish object Acquire/relinquish rights

9 Extras Creations may have relations between each other Actions may have time or place Creations may have subjects

10 Relations References / Is Referenced By to point to other information resources IsBasedOn / IsBasisFor to express intellectual derivation IsVersionOf / HasVersion to express historical evolution Is Format Of / Has Format to identify transformations of media or layout Is Part of / Has Part to record Part/Whole

11 Relations Is IsMetadataAuthorOf / HasMetadataAuthoredBy to name the creator of the metadata IsDefinitionOf / IsDefinedBy to point to the URI of the definition of the semantics IsOwnerOf/ IsOwnedBy to name the owner/repository with custody of a physical thing

12 Resolution of Problems with Dublin Core Separate metadata elements for Creator, Contributor, and Publisher. All are Agents related to Works, Expressions, Manifestations or Items. Confusion between Genre and Format. Both are Form, related to either Work/Expression or Manifestation/Item. Many qualifiers have been proposed for Date. A Work, its Expression, a Manifestation and an Item can each have a particular Date. Apparent redundancy of the element "Source". Source is expressed more clearly as a particular Relation.

13 Unresolved problems 1 Complex objects Indecs view is confused between: single package of material for e-commerce trails of rights and payments of indefinite complexity Dublin Core view is limited to: document-like objects with simple relationships

14 Unresolved problems 2 Cost No system provides useful guidelines to balance cost of metadata against utility Indecs model of e-commerce requires complex metadata that is not needed for information discovery and other applications Dublin Core is struggling with the tension between minimalists and structuralists

15 Unresolved problems 3 Documentation and training Both Indecs and Dublin Core will require a detail set of instructions and codes. Despite many years of effort they are a long way from having such guidelines. In a rapidly changing world, the guidelines will always be out of date. The guidelines will need trained people to understand them. The dream of metadata generated by untrained creators and publishers is far away.

16 Personal Opinion Metadata is valuable only because it enables specific services Information discovery (descriptive) Rendering and display (structural and technical) Commerce (administrative) Long-term preservation (descriptive, structural and technical) All metadata depends on its context "Author" is: descriptive metadata for information discovery administrative metadata for commerce

17 Personal Opinion Metadata is expensive Costs must be balanced against value for specific services There is no correct place and time to gather metadata At source v. by cataloguer or indexer By professional v. automatically At time of creation v. when needed