Extensible Metadata

Developments in the Triangle Digital

Library Project

The Problems:

• heterogeneous data sources– established collections– individual collections– widely differing metadata needs

• A wide range of catalogers

Towards a solution:

• Some standards:– Dublin Core as “lowest common

denominator”– RDBMS as storage / management /

retrieval mechanism– XML as metadata storage / transport

mechanism

Current Implementation

• Database– Oracle

• Middleware– Cocoon

• A Web publishing framework that utilizes Java servlets and XML

Let’s restate the problem(s)

• Collections’ cataloging schemes may have more granularity than Dublin Core is capable of representing.

Example:

• VRA Core:<object> <title>Artemis</title> <description>Artemis slaying Actaeon</description> … <type>bell krater</type> <material>clay</material> <technique>pottery – Red Figure</technique> …</object>

Example:

• Dublin Core:<object> <title>Artemis</title> <description>Artemis slaying Actaeon</description> <description>pottery – Red Figure</description> … <type>bell krater</type> <format>clay</format>…</object>

doesn’t reallycorrespond totechnique

terminology will be confusing to peopleused to VRA

Proposed solution: Handle both DC and other schemata.Store elements that don’t map to Dublin Core…<object> <title>Artemis</title> <description>Artemis slaying Actaeon</description> <description>pottery – Red Figure</description> <type>bell krater</type> <format>clay</format> <meta> <vra:technique>pottery – Red Figure</vra:technique> </meta></object>

Proposed solution: Handle both DC and other schemata.…and map DC elements to other schemas

Dublin Core VRA Core

<title/> <title/>

<description/> <description/>

<type/> <type/>

<format/> <material/>

To accomplish this, we’ll need

• a schema repository– to handle various schemata (both

standard Dublin Core and extended in various ways)

• a crosswalk repository– to handle transforming metadata

records to different formats, such as VRA

Let’s restate the problem(s)• Collections’ cataloging schemes may have

more granularity than Dublin Core is capable of representing.

• Different disciplines have different vocabularies which may overlap.

Example<object> … <subject>tibia</subject> …<object>

Is it (a) a leg bone? Or (b) a Roman flute?Answer: depends on the context…

Proposed solution: Support multiple controlled vocabularies

vocabularies

LCSH, etc

semantic_unitswords and phrases

elements

Let’s restate the problem(s)• Collections’ cataloging schemes may have

more granularity than Dublin Core is capable of representing.

• Different disciplines have different vocabularies which may overlap.

• Different users will have different metadata needs and desires, both in cataloging and retrieving data.

Proposed solution(s):

• Allow users to choose what cataloging schemes they wish to use for entering and retrieving information.

• Allow users to annotate objects and / or “over-write” metadata.

Model

Links• UNC Digital Library Project

– http://www.unc.edu/projects/diglib

• 1999-2000 Digital Library Final Report– http://www.unc.edu/projects/diglib/report.pdf

• Cocoon– http://xml.apache.org/cocoon