4 Bibliographic record: 12345 Name authority record: 8765Title:Cataloguing is fun!Heading:MacDonald, MaryAuthor:Mary MacDonald8765Place of birth:9876EdinburghContent type:text1234LCSH authority record: 5432Media type:5432microformHeading:CatalogingLCSH:Cataloging5432See also:Books65443RDA content type record: 1234Term:textDefinition:Content expressed through a form of notation for language intended to be perceived visually.ISBD media type record: 5432Term:microformDefinition:Media used to store reduced-size images, not readable to the human eye, and designed for use with a device such as a microfilm or microfiche reader.
5 Bibliographic record: 12345 Name authority record: 8765Title:Cataloguing is fun!Heading:MacDonald, MaryAuthor:8765Place of birth:9876Content type:1234Media type:5432Stop! Ambiguous: link not safe.LCSH:5432Identifier: ok to link.123458765Author8765Heading“MacDonald, Mary”8765Heading“MacDonald, Mary”123458765Author8765Place of birth98768765Place of birth98769876Name“Edinburgh”9876Name“Edinburgh”123458765Author8765Place of birth98769876Country45679876Country4567
6 Linked data is not a new idea! It extends concepts of authority control“Preferred” labelsCreate/maintain once; link many timesRe-use of metadataMore than one “attribute” associated with a “heading”E.g. Place of birth of person with name headingConcepts can be applied to authority recordsAs well as bibliographic description recordsFull extension leads to “record” dis-aggregationAll “records” in bibliographic control systems
7 Linked data and RDF Resource Description Framework (RDF) Designed for machine-processing of metadata at global scale (Semantic Web)24/7/365Trillions of operations per secondEverything must be dis-ambiguatedMachines are dumbSimplicity helps!Machine-readable identifiers
8 RDF triple Metadata expressed as “atomic” statements A simple, single, irreducible statementThe title of this book is “Cataloguing is fun!”Constructed in 3 parts“Triple”Subject of the statement = Subject: This bookNature of the statement = Predicate: has titleValue of the statement = Object: “Cataloguing is fun!”This book – has title – “Cataloguing is fun!”subject – predicate - object
9 IdentifiersNeed unambiguous way of identifying each part of the triple for efficient machine-processingHuman labels (“This book”, “has title”) no goodSame thing, different labels; different things, same labelExploit the utility of the URLMachine-readable, regular syntax, unambiguousUniform Resource Identifier (URI)
10 Uniform Resource Identifier Can be any unique combination of numbers and lettersNo intrinsic meaning; it’s just an identifierCan look like a URLBut 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 (“Cataloguing is fun!”)
11 RDF properties Predicates are called properties in RDF “Verbal” part of the metadata statementE.g. “A has author B”, “B has heading ...”Properties link specific instances of two thingsA = a specific book, B = a specific person... = a specific label, character string, annotation=> a “literal”Properties are the links in linked data, the pathways through the Semantic Web to human-readable metadata
12 Labels, global identifiers, linked data Headings can be managed in the same way as other controlled vocabulariesThey are all RDF labelsGlobal identifiers (URIs) and RDF allow distributed authority controlBut without need to copy and maintain in local systemsDifferent labels for the same thing can be linked, and a chain can link a label to a resourceIts all linked data ...
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