Functional requirements for bibliographic linked data: the FR family and the Semantic Web Gordon Dunsire Presented to the ALCTS FRBR Interest Group, ALA Annual, 24 June 2011
Overview • Background • Resource Description Framework • Representing Functional Requirements for the Semantic Web • Some issues • Legacy catalogue records
FRAD Does not cover subjects FRBR Does not cover “authorities” FR Consolidated model FRSAD Semantic Web versions recapitulate this sequence: * Earlier models in use before later models published * Later models re-use elements from earlier models * Reflects semantic development over time * Provides learning curve for FRBR Review Group 1998 2009 2010 2012?
Background • RDA: resource description and access is based on FRBR and FRAD • Bibliographic metadata content guidelines • DCMI RDA Task Group asked to develop an RDF representation of RDA • Following the “London” meeting in April 2007 • Stimulated creation of “FRBR namespaces project” • To develop RDF representation of FRBR
RDF • Resource Description Framework • Basis of the Semantic Web • Metadata expressed as “atomic” statements • A simple, single, irreducible statement • The creator of this work is R. Shankar • Constructed in 3 parts • “Triple”
RDF triples • The creator of this work is R. Shankar • Subject of the statement = Subject: This work • Nature of the statement = Predicate: has creator • Value of the statement = Object: R. Shankar • This work – has creator – R. Shankar • subject – predicate – object • RDF requires the subject and predicate of a triple to have machine-readable identifiers • Uniform Resource Identifier (URI) • Object of triple can be a URI, or a literal string like a title
RDF properties and classes • A predicate is called a property • Properties link two things • A specific work with a specific creator • This work <-> R. Shankar • A generic type of thing is called a class • Works, Persons, Places, etc. • Properties can specify which class the subject and object of a triple should belong to • Subject “domain”; object “range”
Methodology (1) • Open Metadata Registry used for basic representation in RDF • Same approach as RDA • Provides URI assignment; labels, definition, scope note, property range and domain • FR family are entity-relationship models • Entity => RDF Class • E.g. FRBR Work • Entity attribute => RDF property • E.g. FRBR has-intended-audience • Entity-entity relationship => RDF property • E.g. FRBR is-realized-through (Work-Expression)
Classes Properties FRBR Groups are not (super-)classes [FRBR Review Group] Group 1 entities are not classes [some ontologists]
3.2.5 Person The fifth entity defined in the model is person: an individual. The entity defined as person encompasses individuals that are deceased as well as those that are living. Entity => Class Label Definition Scope note 4.4.12 Capture mode Capture mode is the means used to record notation, sound, or images in the production of a manifestation (e.g., analogue, acoustic, electric, digital, optical etc.). Attribute => Property Label Definition Scope note
Verbalised label URI URI for Manifestation
Spanish translation of label - URI remains the same
Methodology (2) • Terminology of labels, definitions and scope notes based as closely as possible on source documentation • E.g. Property label = “has” + attribute name • Classes and properties declared for prior model(s) re-used in current model • E.g. FRAD re-uses URIs from FRBR namespace • E.g. FRBR Expression; FRBR has-key • No re-use of RDF resources from external community namespaces such as Dublin Core Terms • Equivalences likely to be established later
Methodology (3) • FR attribute properties have domain but no range • Required by the model for extensibility • E.g. FRBR has-key (domain = Work) • Relationship properties have domain and range • E.g. FRBR is-realized-through (domain = Work; range = Expression)
General, non-technical issues • Consistency within documentation • Written for human consumption; evidence of variable phrasing to make it more readable • E.g. “prior”, “preceding”, “first” • Consistency of labels of RDF resources • E.g. “has a reproduction” (regular) vs “has reproduction” (irregular) • Documentation refers to sub-types of entity • E.g. “musical work”, “serial” • First pass: sub-type => sub-class • But wrong due to semantic overlap
Opaque URIs • http://iflastandards.info/ns/fr/frbr/frbrer/P1001 • frbrer:P1001 • Not http://iflastandards.info/ns/fr/frbr/frbrer/Work • IFLA operates in a multilingual environment • Anglophone bias avoided • Labels, etc. in English (@en), but no problem in accommodating translations • Allows subsequent changes to alternative and preferred labels without causing confusion • URI must not change!
Linking the FR models • Relationships between separate FR model classes and properties are declared with RDF equivalence and hierarchical properties • E.g. owl:sameAs, rdfs:subClassOf • E.g. FRAD class Corporate Body seems to be a sub-class of FRBR Corporate Body • Will inform the consolidated model • Which may also require additional classes and properties
RDA issues • DCMI RDA Task Group has declared parallel FRBR classes within RDA namespace • Could not wait for FRBR RDF resources to be approved • JSC to decide whether to substitute FRBR namespace resources, or declare equivalence • Conflict with FRBR in RDA implementation scenarios? • RDA Manifestation “embodies” Work and Expression; FRBR allows only Expression
Legacy catalogue records • Domain and range of FR (and RDA) properties inhibit use for creating triples from non-FRBRized catalogue records • Need separate URIs for each specific Work, Expression, Manifestation, and Item • Solution: equivalent properties with no domain or range • Need just a URI for the specific resource described • RDA has such unbounded properties
Thank you • email@example.com • FRBR Review Group • http://www.ifla.org/en/frbr-rg • Open Metadata Registry • http://metadataregistry.org/ • Library Linked Data Incubator Group • http://www.w3c.org/2005/Incubator/lld/ • Sponsors • ALA • Cataloging & Classification Quarterly • MARCIVE, Inc.