Gordon Dunsire, Françoise Leresche, Mirna Willer LIDA, Zadar, 18-21 June 2012 Library Models and Standards, and Their Availability in the Semantic Web Workshop Gordon Dunsire, Françoise Leresche, Mirna Willer

Representing records as RDF triples Gordon Dunsire 11/28/2018 LIDA 2012, Workshop "Library Models and Standards, and the Semantic Web"

Resource Description Framework Metadata statement constructed in 3 parts “Triple” The title of this book is “Treasure island” Subject of the statement = Subject: This book Nature of the statement = Predicate: has title Value 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-processing Human labels (“This book”, “has title”) no good Same thing, different labels; different things, same label Exploit the utility of the URL Machine-readable, regular syntax, unambiguous Uniform Resource Identifier (URI)

RDF and URIs Resource Description Framework requires the subject and predicate of triple to be URIs Object can be a URI, or a literal string (“Treasure island”) If the object URI of one triple is the same as the subject URI of another triple, the triples can be linked together Linked data! Two subject URIs or two object URIs can also be linked

Predicate/ Property Subject Object URI for this book “Treasure island” URI for “has title” “Treasure island” match URI for R.L. Stevenson URI for this book URI for “has author” match URI for “has author” URI for R.L. Stevenson URI for “has name” “Stevenson, R. L.” URI for Edinburgh URI for “has geolocation” URI for “has birthplace”

From record to triples Record ID: 1234 Author: Stevenson, R. L. Title: Treasure island Media type: audio Record or Resource ID => Subject Attribute/field => Predicate Value => Object Subject Predicate Object URI of Resource URI for (has) Author URI for Stevenson, R. L.?

Subject URI Identifies specific resource Must be globally unique Unique global http domain + local unique number E.g. specific library domain + record number E.g. http://myLibrary/1234 Note: This is not a URL! Not the only method … But http URIs are “cool” E.g. use the infrastructure of the Web

Property URI Predicate = RDF property Is there a namespace (set of URIs) for the record schema? E.g. If ISBD record – Yes! Is there a URI for the attribute/property? ISBD “has author” x ISBD “has title proper”  ISBD “has media type”  If not, look in another namespace Mix and match (if semantic constraints permit)

Object URI Optional Labels not usually given a URI If no URI, value is a literal and cannot be linked Labels not usually given a URI Human-readable identifier No need to identify the identifier E.g. title “Treasure island” “Value vocabulary” namespaces E.g. ISBD area 0 vocabularies E.g. Virtual International Authority File E.g. Library of Congress Subject Headings …

Record ID: 1234 Author: Title: Media type: Stevenson, R. L. Treasure island audio myLibrary:1234 rda:author viaf:95207986 myLibrary:1234 isbd:P1004 “Treasure island” myLibrary:1234 isbd:P1003 isbd:T1001

“ستيفنسن، روبرت لويس، 1850-1894 م.” foaf:name “ستيفنسن، روبرت لويس، 1850-1894 م.” foaf:name “Stevenson, Robert Louis, 1850-1894” viaf: 95207986 rda:author myLibrary: 1234 isbd:P1004 “Treasure island” isbd: T1001 “audio” skos:prefLabel isbd:P1003 skos:definition “Medios utilizados para almacenar sonido grabado, diseñado para su uso con un dispositivo de reproducción como un tocadiscos, reproductor de audiocasete, reproductor de CD, reproductor de MP3 o iPod. ”

Interoperability Data interoperability requires Schema alignment Schema alignment in RDF requires “ontological” triples which indicate semantic relationships between elements (classes and properties) Applying ontological triples to data triples produces (infers) new data triples

Entailed triple has same nature as second triple myLibrary:1234 isbd:P1004 “Treasure island” urLibrary:4321 rda:titleProper “Treasure island” isbd:P1004 rdfs:subPropertyOf rda:titleProper Narrower meaning or scope Broader meaning or scope entails (infers) myLibrary:1234 rda:titleProper “Treasure island” Entailed triple has same nature as second triple = functional interoperability First triple available for other applications