z39.50, xml & rdf applications zig tutorial january 2000 poul henrik jørgensen, [email protected]...

Z39.50, XML & RDF Applications

ZIG Tutorial January 2000

Poul Henrik Jørgensen, [email protected]

Danish Bibliographic Centre, www.dbc.dk

ZIG 2000-01-19 Z39.50, XML & RDF / DBC-PHJ 2

Contents Z39.50 Overview Z39.50 and XML Resource Description Framework, RDF Z39.50, XML and RDF Applications


Web Search Example


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


Z39.50 Search Example


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


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?


Z39.50 XML Example


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


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)


RDF Statement The resource http://doc123 (Subject). has the Title (Property) ”Out of Africa” (Value) has the Creator (Property) ”Karen Blixen” (Value)


RDF Graph Example

http://doc123

Karen Blixen

TitleOut of Africa

Creator


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


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>


RDF XML IFLA 4LM Example


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.


RDF Graph Navigation

The generic ”Out of Africa” object is expanded to show related works including three translations (some attribute names are in Danish)


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)

z39.50, xml & rdf applications zig tutorial january 2000 poul henrik jørgensen, [email protected]...

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