Transcript metadata
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 • W3C HTML 4.0 Recommendation http://www.w3.org/TR/REChtml40/struct/global.html#edef-META • Web Design Group http://www.stack.nl/htmlhelp/reference/html40/ 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) [email protected]"> <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 Newcastle upon Tyne NE1 7RU UK"> <LINK REL=SCHEMA.dc HREF="http://purl.org/metadata/dublin_core_elements#author"> <META NAME="DC.date" CONTENT="(TYPE=creation) (SCHEME=ISO31) 1996-09-02"> 7 Metadata Development • Which format to use? – Dublin Core? New standards? www.ariadne.ac.uk/issue5/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.w3.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.w3.org"> <s:Publisher>World Wide Web Consortium</s:Publisher> Identify the resource to be described <s:Title>W3C Home Page</s:Title> <s:Date>1998-10-03T02:27</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