z39.50, xml & rdf applications zig tutorial january 2000 poul henrik jørgensen, [email protected]...
TRANSCRIPT
Z39.50, XML & RDF Applications
ZIG Tutorial January 2000
Poul Henrik Jørgensen, [email protected]
Danish Bibliographic Centre, www.dbc.dk
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Contents Z39.50 Overview Z39.50 and XML Resource Description Framework, RDF Z39.50, XML and RDF Applications
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Web Search Example
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Z39.50 Overview Z39.50 Targets (Z-Servers) supports a standard
system interface to Z39.50 Origins (Z-Clients) Z-Clients support specialised user interfaces Z-Clients submit metadata Searches to Z-Servers Z-Servers returns pointers to relevant resources Z-Servers can return structured information
according to requests from Z-Clients Z-Clients can access different Z-Servers – and
vice versa
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Z39.50 Search Example
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XML Overview HTML was intended to handle formatted text XML is designed by W3C to handle structured
information Programs may access XML structures via the Document
Object Model (DOM) Application Program Interface Related standards handle transformations (XSL) and
searching of XML structures (XQL) XML may transform the Web from a large text archive to
a large database of structured information
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Z39.50 and XML Z39.50 handle XML as another transfer
syntax like SUTRS, MARC or GRS-1 XML can do many of the same things as
GRS-1- and XML can be edited by hand Several Z39.50 Profiles use XML for
Metadata, Item Orders, Electronic Document Delivery and Explain Info
What about Holdings data?
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Z39.50 XML Example
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Resource Description Framework Describe relationships and attributes of (Internet)
resources, i.e. advanced metadata Based on Directed Labelled Graphs (DLG) and
classical Information Analysis May be represented by XML – but is basically
independent of any representation format. Attributes and Relation types may be defined by
XML Namespaces, e.g. Dublin Core
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RDF Elements An RDF Resource is an instance of one or
more Classes Resources have Properties (=attributes) A Class may be a Subclass of another Class Properties are Values or Relations RDF Statements: Resource (Subject) +
Property (Predicate) + Value (Object)
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RDF Statement The resource http://doc123 (Subject). has the Title (Property) ”Out of Africa” (Value) has the Creator (Property) ”Karen Blixen” (Value)
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RDF Graph Example
http://doc123
Karen Blixen
TitleOut of Africa
Creator
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RDF, IFLA 4LM and DC RDF can use any namespace for properties Several namespaces can be referenced in a
given RDF structure Several Z39.50 Profiles use the RDF DC
specification for cross-domain access DBC use RDF with IFLA Entity-
Relationship Model (IFLA 4LM) to navigate normative data
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RDF Dublin Core Example<?xml version="1.0"?> <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-
syntax-ns#" xmlns:dc="http://purl.org/dc/elements/1.0/">
<rdf:Description rdf:about="http://www.ukoln.ac.uk/metadata/resources/dc/datamodel/ WD-dc-rdf/">
<dc:title> Guidance on expressing the Dublin Core within the Resource Description Framework (RDF) </dc:title>
<dc:creator> Eric Miller </dc:creator> <dc:subject> Dublin Core; Resource Description Framework;
RDF; eXtensible Markup Language; XML </dc:subject> <dc:format> text/html </dc:format> <dc:language> en </dc:language> </rdf:Description> </rdf:RDF>
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RDF XML IFLA 4LM Example
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RDF Graph & IFLA 4LM
Screen-dumps from the VisualCat Client ©Portia I/S
A Person object has several attributes incl. six names (i.e. synonyms), dates and a title.This Person is related to an object, with several attributes including Title (”Out of Africa”)Users can click on any object to see related objects as illustrated in the following slide.
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RDF Graph Navigation
The generic ”Out of Africa” object is expanded to show related works including three translations (some attribute names are in Danish)
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Z39.50, XML and RDF Applications Z39.50 can support XML as transfer syntax Z39.50 can support XQL search language Z39.50 can navigate RDF structures Z39.50 could support XML Namespaces Z39.50 could use HTTP - and possibly
Simple Object Access Protocol (SOAP)