linked data presentation to aall 2012 boston

Law Libraries and Linked Data Vocabularies

Thriving in an Open World

AALL Boston 7/23/2012 2

Linked Data is About Machines

Traditional cataloging considers identification via text adequate (for physical things mostly) A ‘record’ aggregates statements, but

the identity of the resource being described is often squishy (a title? Title plus author? ISBN?)

Digital identity must be significantly clearer (a URI/URL?) because immediate access is expected

Our entry into the digital world is forcing us to look more carefully at our practices


Linked Data is Inherently Chaotic

Requires creating and aggregating data in a broader context There is no one ‘correct’ record to be made

from this, no objective ‘truth’ This approach is different from the

cataloging tradition BUT, the focus on vocabularies is one we can

work with In the SemWeb world vocabularies are

more complex than the thesauri we know


Model of ‘the World’ /XML XML assumes a 'closed' world (domain),

usually defined by a schema: "We know all of the data describing this

resource. The single description must be a valid document according to our schema. The data must be valid.”

XML's document model provides a neat equivalence to a metadata 'record’


Model of ‘the World’ /RDF RDF assumes an 'open' world:

"There's an infinite amount of unknown data describing this resource yet to be discovered. It will come from an infinite number of providers. There will be an infinite number of descriptions. Those descriptions must be consistent."

RDF's statement-oriented data model has no notion of 'record’ (rather, statements can be aggregated for a fuller description of a resource)


RDVocab: Most Important Goals

Bridge the XML and RDF worlds Ensure ability to map between RDA and

other element sets Provide a sound platform for extension of

RDA Vocabularies into new and specialized domains

Consider methods for expressing AACR2 structures in technical ways to ease the pain of transition to RDA


RDVocab Structure, Simplified RDA Properties declared in two separate

hierarchies: An ‘unconstrained’ vocabulary, with no explicit

relationship to FRBR entities A subset of classes, properties and

subproperties with FRBR entities as ‘domains’ Pros: retained usability in or out of

libraries; better mapping to/from non-FRBR vocabularies

Cons: still seems too complex to many SemWeb implementers (many using BIBO)


Why Unconstrained Properties? The ‘bounded’ properties should be seen as the

official JSC-defined RDA Application Profile for libraries What’s still lacking is the addition of the necessary

constraints: datatypes, cardinality, associated value vocabularies

Extensions and mapping should be built from the unconstrained properties Unconstrained vocabularies necessary for use in

domains where FRBR not assumed or inappropriate Mapping from vocabularies not using the FRBR model

directly to ones that do (and back) creates serious problems for the ‘Web of Data’


Property (Generalized, no FRBR relationship)

Subproperty (with relationship to one FRBR entity)

FRBR Entity

SemanticWeb

Library ApplicationsThe Simple Case:

One Property-- One FRBR Entity


Property (Generalized, no FRBR relationship)



FRBR Entity

FRBR Entity

SemanticWeb

Library ApplicationsThe Not-So-Simple Case: One Property—more than

One FRBR Entity


Roles: Attributes or Properties? In 2005, the DC Usage Board worked with LC to

build a formal representation of the MARC Relators so that these terms could be used with DC This work provided a template for the

registration of the role terms in RDA (in Appendix I) and, by extension, the other RDA relationships

Role and relationship properties are registered at the same level as elements, rather than as attributes (as MARC does with relators, and RDA does in its XML schemas)


Aggregated Statements

RDA (and MARC 21) include pre-coordinated, aggregated statements that have traditionally been handled as a whole, ex.: Publication, Distribution, Manufacture and Production statements, etc. These were originally pulled together for the efficient

display on catalog cards Some users will prefer to deal with the issue at the

display level, by using separate properties and configuring the display to manipulate the order

To deal with retrospective, transitional and (some) prospective needs, we must address the desire to continue this practice


Aggregated Statement (no domain or range)

Aggregated Statement Subproperty

Range: RDA Syntax Encoding Scheme (Subclass of RDF Datatype)

Dom

ain

: FRB

R E

ntity

Range: [Specific] Encoding Scheme (Subclass)

General Property (no domain or range)

Subproperty

Pre-coordinated Statements: Structure


Publication Statement (no domain or range)

Publication Statement (Manifestation)

Range: RDA Syntax Encoding Scheme (Subclass of RDF Datatype)

Dom

ain

: M

anife

statio

n

Range: Publication Statement Encoding Scheme (Subclass)

Place of publication (no domain or range)

Place of publication (Manifestation)

Pre-coordinated Statements: Example


Vocabulary Extension

The inclusion of unconstrained properties provides a path for extension of RDA into specialized library communities and non-library communities They may have a different notion of how FRBR

‘aggregates’ (For example, a colorized version of a film may be viewed as a separate work)

They may not wish to use FRBR at all They may have additional, domain-specific

properties to add, that could benefit from a relationship to the RDA properties


RDA:adaptedAs

RDA:adaptedAsARadioScript

hasSubprope

rty


RDA:adaptedAs


KidLit:adaptedAsAPictureBook

hasSubproperty

hasSubprope

rty

Extension using Unconstrained Properties


RDA:adaptedAs


KidLit:adaptedAsAPictureBook

hasSubproperty

hasSubprope

rty

KidLit:adaptedAsAChapterBook

hasS

ubprop

e

rty

Extension using Unconstrained Properties


Mapping

Building relationships between vocabularies is not necessarily a proprietary activity or tied to particular applications (not ‘crosswalking’ as we have understood that term)

http://MARC21rdf.info provides a beginning point for mapping library data that is easily shared and modified to meet a variety of needs

New approaches go beyond ‘sameAs’ and suggest the potential for more granular, nuanced relationships

Mapping in this context retains the original data ‘as is’ and provides a view through the lens of another structure (with minimal loss of richness)

http://MARC21rdf.info/

AALL Boston 7/23/2012 21http://marc21rdf.info

http://marc21rdf.info/


Property Detail: Relator codes

http://marc21rdf.info/elements/1XXM1000_4

Tag: 100 (Main entry-Personal Name)

Ind2: # (no caption)Sub: 4 (Relator code)


RDF graph of 00X mapping pattern for an attribute with more than one valueand no significance in the order of values


Partial RDF graph of 00X mapping pattern for two or more attributes withmore than one value and significance in the order of values

The Bottom Line

Our big investment is (and has always been) in our data, not our systems

Over many changes in format of materials, we’ve always struggled to keep our focus on the data content that endures, regardless of differences in data management strategy or presentation format

We have made good progress in moving towards our common future, but we can’t be afraid to change, or afraid to fail


Thank you! Questions?

Contact info: [email protected]

Metadata Matters: http://managemetadata.com/blog


mailto:[email protected]

mailto:[email protected]

http://managemetadata.com/blog



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