Upload
gabriella-harrison
View
223
Download
0
Tags:
Embed Size (px)
Citation preview
ISBD for the Semantic Web: namespaces, elements, vocabularies, application profile
Gordon DunsirePresented at Centar zu Stalno Stručno
Usavršavanje (CSSU), Zagreb21 Nov 2011
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”)
Creating namespaces and URIs
ISBD is using the Open Metadata RegistryCan assign a running “number” to the base to
create a new URISet of properties (= predicates) for creating
basic triples about other propertiesE.g. rdfs:label for assigning a human-readable
label to an RDF property (or class)isbd:P1001 - rdfs:label - “has content form”
A property of a property
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)