Linked data and the implications for library cataloguing: metadata models and structures in the Semantic Web Gordon Dunsire Presented at the Canadian Library Association Annual Conference, 26- 29 May 2011, Halifax, Nova Scotia
Jan 07, 2016
Linked data and the implications for library cataloguing:
metadata models and structures in the Semantic Web
Gordon DunsirePresented at the Canadian Library
Association Annual Conference, 26-29 May 2011, Halifax, Nova Scotia
Outline
Context: evolution of the catalogue recordRDF 101Library metadata models/schemas in RDF
FRBR, RDA, ISBD, DCT, BiBO, ...From record to triples: worked example
A short historyof the evolution
of the library catalogue record
Lee, T. B.
Cataloguing has a future. - Audio disc (Spoken word). - Donated by the author.
1. Metadata
In the beginning ...
... the catalogue card
Author:
Title:
Content type:
Provenance:
Subject:
Lee, T. B.
Cataloguing has a future
Spoken word
Audio disc
Metadata
Donated by the author
Carrier type:
From flat-file record ...
... to relational record
Name:Biography:
...
Name authority
Term:Definition:
...
Subject authority
Bibliographic description
Author:
Title:
Content type:
Provenance:
Subject:
Lee, T. B.
Cataloguing has a future
Spoken word
Audio disc
MetadataDonated by the author
Carrier type:
From flat-file description ...
... to FRBR record
Name:Biography:
...
Name authority
Term:Definition:
...
Subject authority
Bibliographic description
Item
Manifestation
Author:
Content type:
Subject:
Spoken word
Expression
Work
Lee, T. B.
Metadata
From FRBR record ...
... to extinction!
Name:
Name authority
Term:
Subject authority
Item
Manifestation
Expression
Work
Provenance: Donated by the author
Subject:Author:
Title: Cataloguing has a future
Content type: Spoken word
Audio discCarrier type:Term:
RDA content type
Term:
RDA carrier type
Donor:
Title:
Amazon/Publisher
Where is the record?
Implicit, not explicitEverywhere and nowhere
A semantic Web will allow machines to create the record just-in-timeWe will not have to maintain records just-in-case
The user will have control over the presentationI want to see an archive or library or museum or Amazon
or Google or Flickr or ? displayAnd by avoiding duplication, we can all get on with
describing new stuff ...
The hyperdimensional (Tardis) card
Lee, T. B.
Cataloguing has a future. - Audio disc (Spoken word). - Donated by the author.
1. Metadata
Audio shop
Lee MuseumSpoken word archive
W3C Library
“TARDIS four port USB hub, for office-bound Time Lords:Open a time vortex on your desk” – Pocket-lint
RDF 101
Semantic Web
“machine-readable metadata”Faster! 24/7/365! Global!
Metadata expressed as “atomic” statementsA simple, single, irreducible statement
The title of this book is “Treasure island”
In a standard machine-processable formatResource Description Framework (RDF)
Resource Description Framework
Metadata statement constructed in 3 parts“Triple”
The title of this book is “Treasure island”Subject of the statement = Subject: This bookNature of the statement = Predicate: has titleValue of the statement = Object: “Treasure island”
This book – has title – “Treasure island”subject – predicate - object
Identifiers
Need unambiguous way of identifying each part of the triple for efficient machine-processingHuman labels (“This book”, “has title”) no good
Same thing, different labels; different things, same label
Exploit the utility of the URLMachine-readable, regular syntax, unambiguous
Uniform Resource Identifier (URI)
Uniform Resource Identifier
Can be any unique combination of numbers and lettersNo intrinsic meaning; it’s just an identifying label
Can look like a URLhttp://iflastandards.info/ns/isbd/elements/P1001But does not lead to a Web page (in principle ...)
RDF requires the subject and predicate of triple to be URIsObject can be a URI, or a literal string (“Treasure
island”)
Namespaces
URI can be constructed from a base plus a unique, identifying suffixhttp://iflastandards.info/ns/isbd/elements/+ P1001
Base is known as a namespaceCan be abbreviated by human programmer
“isbd” = http://iflastandards.info/ns/isbd/elements/isbd:P1001
Machine expands abbreviation for processing
Everything as triples in RDF
Every aspect of the metadata must be expressed in RDF to be machine-processableMetadata about real-world objects (books,
people, etc.)Metadata about the predicates (definition, label,
scope, etc.)Common predicates apply to many types of thing
(human-readable label, etc.)High-level RDF namespaces (rdfs, owl)
RDF is expressed in RDF (“bootstrap”)
Library namespaces
Creating namespaces and URIs
FRBR/FRAD/FRSAD, ISBD, and RDA are using the Open Metadata RegistryCan assign a running “number” to the base to
create a new URISet of properties for creating basic triples
Properties = predicatesrdfs:label for assigning a human-readable label to
the subjectisbd:P1001 - rdfs:label - “has content form”
Subject Predicate Object
isbd:P1001 rdfs:label “has content form”
Subject Predicate Object
isbdcf:T1008 skos:prefLabel “spoken word”
Application profile
Need a way to specify how a useful “record” can be constructed from RDF triples
Which triples are involved, and from which namespaces?
Sequence? Repeatable? Mandatory?Sub-component aggregations
Publication statement = place + name + dateContent rules?
Mandatory Not repeatable Aggregation of simpler elements
Syntax of aggregation (punctuation)
Getting triples from records
Linking Open Data cloud (LOD)
Diagram by Richard Cyganiak and Anja Jentzsch. http://lod-cloud.net/
LOD: “Library” corner
Why get involved?
To share our dataWe work for “society”
To share our expertise and experience150 + years
To promote the power of libraries (and archives and museums)
To survive
From record to triples (in 9 stages)Very large numbers of records
Catalogue records, finding aids, etc.300 million; 1 billion?
High quality metadataIn comparison with other communities
Each record may generate many triples200 “raw” triples (no inferences) per MARC record?
Very, very large numbers of triplesBillions? Trillions?
1. Take a recordField/attribute ValueRecord ID 54321Title Museum archives: an introductionAuthor Wythe, DeborahDate 2004LCSH Museum archivesMedia/GMD ElectronicContent form Text
2. Disaggregate to single statementsRecord Attribute Value54321 (has) title Museum archives: an
introduction54321 (has) author Wythe, Deborah54321 (has) date 200454321 (has) LCSH Museum archives54321 (has) media type Electronic54321 (has) content form Text
3. Create URI for record
Must be unique, so 54321 no good on its ownhttp URIs are a good thing (W3C)So add record ID to a unique http domain
E.g. http://MyLibraryX.com (unique to the library)+ 54321
http://MyLibraryX.com/54321(or http://MyLibraryX.com#54321)
This is not a URL!
4. Replace record ID with URIURI Attribute Valuemlx:54321 (has) title Museum archives:
an introductionmlx:54321 (has) author Wythe, Deborahmlx:54321 (has) date 2004mlx:54321 (has) LCSH Museum archivesmlx:54321 (has) media type Electronicmlx:54321 (has) content form Text
“mlx” = qname (xmlns) = shorthand for “http://MyLibraryX.com/”
5. Find URIs for attributesAttributes are modelled as RDF properties (predicates) in
“element set” namespacesE.g. Dublin Core terms (dct); ISBD (isbd); FRBR (frbrer); RDA
(rdaxxx); Bibliographic Ontology (bibo); etc.Choose a namespace, find property with same (or closest)
“meaning” (e.g. definition) as attributeNearest property minimises loss of information
Get URI for property If no suitable property, choose another namespace
Properties do not have to come from single namespaceMatch and mix!
5 (cont). Find URI for titlehttp://purl.org/dc/terms/title (dct:title)http://iflastandards.info/ns/isbd/elements/
P1014 (isbd:P1014)hasTitleProper
http://RDVocab.info/Elements/titleProper (rdaGR1:titleProper)
5 (cont). Find URI for authordct:creatorrdarole:author(isbd does not cover “headings”)
5 (cont). Find URI for datedct:dateisbd:P1018
hasDateOfPublicationProductionDistribution
rdaGr1:dateOfPublication
5 (cont). Find URI for LCSHLCSH is a subject vocabulary
Controlled termsSo attribute is really “subject”
And the term itself is the valuedct:subject
5 (cont). Find URI for media typeAssuming record uses new ISBD Area 0 ...isbd:P1003
hasMediaType
5 (cont). Find URI for content formAssuming record uses new ISBD Area 0 ...isbd: P1001
hasContentForm
6. Replace attributes with URIsURI URI Valuemlx:54321 isbd:P1014 Museum archives:
an introductionmlx:54321 rdarole:author Wythe, Deborahmlx:54321 isbd:P1018 2004mlx:54321 dct:subject Museum archivesmlx:54321 isbd:P1003 Electronicmlx:54321 isbd:P1001 Text
7. Find URIs for values If object of a triple is a URI, it can link to the subject
of another triple with the same URILinked data!
Values from controlled vocabularies may have URIsPossible vocabularies: author, subject, ISBD Area 0NOT: title, date
For author: Virtual International Authority File (VIAF)For LCSH: Library of Congress Authorities &
VocabulariesFor ISBD Area 0: Open Metadata Registry
7 (cont). Find URI for authorAuthor: Wythe, DeborahVIAF: http://www.viaf.org/
viaf:31899419/#Wythe,+Deborah
7 (cont). Find URI for subject (LCSH)LCSH: Museum archivesLoC: http://id.loc.gov/authorities/
lcsh:/sh85088707#concept
7 (cont). Find URIs for ISBD Area 0Media type: ElectronicISBD media type
isbdmt:T1002Content form: TextISBD Content form
isbdcf:T1009
8. Replace values with URIssubject predicate objectmlx:54321 isbd:P1014 “Museum archives: an
introduction”mlx:54321 rdarole:author viaf:31899419/#Wythe,
+Deborahmlx:54321 isbd:P1018 “2004”mlx:54321 dct:subject lcsh:/
sh85088707#concept mlx:54321 isbd:P1003 isbdmt:T1002mlx:54321 isbd:P1001 isbdcf:T1009
9. Publish triples (linked data)mlx:54321 | isbd:P1014 | “Museum archives: an
introduction” mlx:54321 | rdarole:author | viaf:31899419/#Wythe,
+Deborahmlx:54321 | isbd:P1018 | “2004”
mlx:54321 | dct:subject | lcsh:/sh85088707#concept
mlx:54321 | isbd:P1003 | isbdmt:T1002
mlx:54321 | isbd:P1001 | isbdcf:T1009
Linked data chains
mlx:54321 | dct:subject | lcsh:/sh85088707#concept
lcsh:/sh85088707#concept | skos:related | rameau:XXX
rameau:XXX | frbrer:isSubjectOf | mly:98765
rameau:XXX | skos:prefLabel | “archives du musée”
mly:98765 | rda:titleOfTheWork | “Managing archives in museums”
Linked data cluster = “record”mlx:54321 | isbd:P1014 | “Museum archives: an
introduction” mlx:54321 | rdarole:author | viaf:31899419/#Wythe,
+Deborahmlx:54321 | isbd:P1018 | “2004”
mlx:54321 | dct:subject | lcsh:/sh85088707#concept
mlx:54321 | isbd:P1003 | isbdmt:T1002
mlx:54321 | isbd:P1001 | isbdcf:T1009
Metadata focus
Shift of focus of metadata creation, maintenance, storage, preservation (by professionals, amateurs, machines)
From Record To Statement(s) = triple(s)
But metadata display ...... aggregates triples (from multiple sources) to create records on the fly