Metadata – Information about information – Different objects, different forms – e. g. Library catalogue record Property: Value: Author Publisher Date published Subject classification ISBN Ian Beardwell Pitman 1994 Human Resource Management ISBN 0 273 60244 6 1
Why is it important? – Describe and locate information – Judge relevance of information – Promote good information management • Plus. . – Search tools and information gateways beginning to use metadata when locating and describing resources www. altavista. co. uk/cgi-bin/addurl. jsp 2
HTML 'META' Tag References • W 3 C HTML 4. 0 Recommendation http: //www. w 3. org/TR/REChtml 40/struct/global. html#edef-META • Web Design Group http: //www. stack. nl/htmlhelp/reference/html 40/ head/meta. html 3
Interpreting Attributes • Similar attributes may be interpreted differently eg. DATE -what does it mean? – the date the resource was put on the web? – the date the original paper copy was written? • Consistency of values is important: – it ensures searching for information is effective – it allows standard searches to be made 4
Setting Parameters • Inconsistencies can be reduced: – Clear labelling of attributes • lastname, initials, title – Formats and rules • formats Author = Beardwell, I, Dr Date = 01 -Jan-97 • cataloguing rules guidance on interpreting labels 5
Dublin Core (DC) • Workshop held in Dublin, Ohio -1995 – 'Document-Like Objects' • • • HTML, Postscript, images 15 core elements: Title, Creator, Subject, Description, Publisher, Contributors, Date, Type, Format, Identifier, Source, Language, Relation, Coverage and Rights Flexibility provided by qualifiers: – Type: distinguishes different uses of an element – Scheme: identifies recognised coding system Link tag points to definition of DC element 6
DC Example <META NAME="DC. title" CONTENT=" Metadata Talk"> <LINK REL=SCHEMA. dc HREF="http: //purl. org/metadata/dublin_core_elements#title"> <META NAME="DC. subject" CONTENT="(SCHEME=keyword) Dublin Core, Metadata, Loughborough"> <LINK REL=SCHEMA. dc HREF="http: //purl. org/metadata/dublin_core_elements#subject"> <META NAME="DC. author" CONTENT="(TYPE=name) Dave Hartland"> <LINK REL=SCHEMA. dc HREF="http: //purl. org/metadata/dublin_core_elements#author"> <META NAME="DC. author" CONTENT="(TYPE=email) D. W. Hartland@newcastle. ac. uk"> <LINK REL=SCHEMA. dc HREF="http: //purl. org/metadata/dublin_core_elements#author"> <META NAME="DC. author" CONTENT="(TYPE=postal) Netskills, University Computing Service, University of Newcastle upon Tyne NE 1 7 RU UK"> 7 <LINK REL=SCHEMA. dc HREF="http: //purl. org/metadata/dublin_core_elements#author">
Metadata Development • Which format to use? – Dublin Core? New standards? www. ariadne. ac. uk/issue 5/metadata-masses/intro. html • Format can be easily altered by generators – DC DOT www. ukoln. ac. uk/metadata/dcdot/ • Separate the metadata from the information • Resource Description Framework (RDF) 8
RDF • Resource Description Framework – aims to provide the infrastructure to exchange metadata on the web – allows integration of different metadata schemes – enables automated processing of web resources – interoperability between applications that exchange machineunderstandable information • Syntax uses XML www. w 3. org/RDF/ 9
Remote definition of the RDF statements and the XML namespace 's: ' <rdf: RDF xmlns: rdf="http: //rdf-url" Example xmlns: s="http: //org. com"> <rdf: Description about="http: //www. w 3. org"> <s: Publisher>World Wide Web Consortium</s: Publisher> Identify the resource to be described <s: Title>W 3 C Home Page</s: Title> <s: Date>1998 -10 -03 T 02: 27</s: Date> </rdf: Description> </rdf: RDF> Common group name (namespace) Metadata 10
Uses of RDF • • Resource discovery - search engines Cataloguing - describe content and content relationships Describing intellectual property rights Intelligent software agents - info sharing Content rating Privacy preferences/policies Collections of pages as a single "document" • "RDF with digital signatures will be key to building the 'Web of Trust' for electronic commerce, collaboration, and other applications. " 11
Disadvantages of Metadata – In the short-term, metadata imposes a load on the server – Metadata stored in separate files? – Difficult to convince information providers of its importance – Need for standardised usage and procedures – Not trusted by some search engines - 'keyword spamming' 12
Future… – Metadata is becoming very important – Metadata may need to be added retrospectively to thousands of documents – Start collecting data now! – Automate as much as possible – Ensure information providers use metadata 13
Please do not forget to visit the following web site for more information: http: //dublincore. org/ 14
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