Metadata and the World Wide Web Presented by Terry Vaughn INF 385E September 23, 2003
<metadata> What is it? Literally means data about data. Data that describes the - Properties (name, size, data type) - Context (location, relationships, audience) of Information Resources - documents (html, pdf, doc) - images and video (jpg, tiff, mpg) - audio (mp3, wav) Can be a database record, part of the resource, or a surrogate file Must be structured and machine-readable
Analogs in the physical world <metadata> Analogs in the physical world - Bibliographies - Indexes - Catalogs * Just imagine if we did not have these tools in the real world. How would you refer to or find information? You'd just have to flip through pages of books, etc. looking for what you wanted. * That analogy reflects the state of the WWW today (outside of intranets)
<metadata> What is its purpose? For those who design information systems, it facilitates - Description - Organization - Management - Preservation For those who use information systems, it improves - Access - Quality - Relevance Bottom line: Proper implementation adds value
Implementations on the World Wide Web <metadata> Implementations on the World Wide Web Extensible Markup Language (XML) - De facto standard for document markup - Grammar for most metadata schema on the web A sampling from the universe of metadata formats and schema Meta Content Framework (MCF) HTML <meta> tags Document Type Definition (DTD) Digital Item Declaration Language (DIDL) Platform for Internet Content Selection (PICS) Dublin Core (DC) RDF Site Summary (RSS) Darpa Agent Markup Language (DAML+OIL) Resource/Property/Value Syntax (RPV) SQL Data Definition Language (DDL) Resource Description Framework (RDF) YAML Ain't Markup Language (YAML)
Implementations on the World Wide Web <metadata> Implementations on the World Wide Web Document Type Definition (DTD) Specifies the structure and elements that can be included in a document. Informs a validating parser what tags are valid and how they should be arranged
Implementations on the World Wide Web <metadata> Implementations on the World Wide Web HTML <meta> tags - Set property/value pairs that describe the document - Can embed other standards like PICS or DC Example: <HEAD> <META http-equiv="PICS-Label" content='(PICS-1.1 "http://www.gcf.org/v2.5" labels on "1994.11.05T08:15-0500” until "1995.12.31T23:59-0000” for "http://w3.org/PICS/Overview.html" ratings (suds 0.5 density 0 color/hue 1)) '> <TITLE> ... document title ... </TITLE> </HEAD> Source: W3C.org
Implementations on the World Wide Web <metadata> Implementations on the World Wide Web Meta Content Framework (MCF) - Seeks to establish a common metadata syntax and structure - Enables applications to manage resources without knowing schema in advance - Goal: Interoperability Applications - Describing the structure of websites and channels - Threading email - E-commerce
Implementations on the World Wide Web <metadata> Implementations on the World Wide Web Dublin Core (DC) Defines a basic element set for describing networked resources Has two levels: - Simple: Consists of 15 Elements - Qualified: Adds one more Element, Audience, and Qualifiers, which refine the semantics of the elements - Improves resource discovery for specialized domains DC Element Set - Content: Coverage, Description, Type, Relation, Source Subject, Title, Audience - Intellectual Property: Creator, Contributor, Publisher, Rights - Instantiation: Date, Format, Identifier, Language
<metadata> A few more for the road… - Platform for Internet Content Selection (PICS) Resource Description Framework (RDF) RDF Site Summary (RSS) - Darpa Agent Markup Language (DAML+OIL)
New concepts relating to metadata Information Foraging - Pioneered by Stuart Card, Peter Pirolli, et al. at PARC - Compares people seeking information to animals foraging for food - “Informavores” - People seek maximum return for minimum effort Information Scent - Description ~ Metadata ~ Scent - If information is not adequately described, it will not give off enough scent for those seeking it - Scent helps people decide what information to consume Goal: Make descriptions accurately represent the resource. People who are not seeking it will not waste their time, while those seeking it can find it faster with less effort.
<metadata> Looking forward Semantic Web - Extension of the web where resources are given well-defined meaning and context - Enables applications to find, use, exchange and reuse resources more effectively - Relies on accurate metadata, ontologies - Standards: URI, XML, RDF, DAML+OIL
<metadata> Conclusions People need information to survive and advance Metadata (physical or virtual) enables us to organize information Which, in turn, enables us to advance knowledge
<metadata> References Berners-Lee, T., & Miller, E. (2002 , October). The Semantic Web Lifts Off. ERCIM News Online Edition, 51. Retrieved September 17, 2003, from http://www.ercim.org/publication/Ercim_News/enw51/berners-lee.html Berners-Lee, T., Hendler, J. & Lassila, O. (2001, May). The Semantic Web. Scientific American.com. Retrieved September 17, 2003, from http://www.scientificamerican.com/article.cfm?articleID=00048144-10D2-1C70- 84A9809EC588EF21&catID=2 Bray, T., Guha, R.V. (1997, June 6). Meta Content Framework Using XML. Retrieved September 16, 2003 from http://www.w3.org/TR/NOTE-MCF-XML-970624/ Card, S. & Pirolli, P. (1999, January). Information Foraging. Retrieved September 17, 2003 from http://www2.parc.com/istl/projects/uir/pubs/items/UIR-1999-05-Pirolli-Report-InfoForaging.pdf Chi, E. H., Pirolli, P. & Pitkow, J. (2000). The Scent of a Site: A System for Analyzing and Predicting Information Scent, Usage, and Usability of a Web Site. Retrieved September 16, 2003, from http://www2.parc.com/istl/projects/uir/pubs/items/UIR-2000-01-Chi- CHI2000-WebVisualization.pdf Dean, M. (2003 , March 5). About DAML. Retrieved September 17, 2003, from DAML Program Web site: http://www.daml.org/about.html
<metadata> References Hillmann, D. (2003, August 26). Using Dublin Core. Retrieved September 17, 2003 from Dublin Core Metadata Initiative Web site: http://dublincore.org/documents/usageguide/ Jacobs, I., Le Hors, A., & Raggett, D. (1999, December 24). Document Type Definition. HTML 4.01 Specification (chap. 21). Retrieved September 15, 2003 from W3C.org Web site: http://www.w3.org/TR/REC-html40/sgml/dtd.html King, A. B. (2003, April 14). Introduction to RSS. Retrieved September 17, 2003, from http://www.webreference.com/authoring/languages/xml/rss/intro/ Meta-data from FOLDOC. (1997, April 6). Retrieved September 12, 2003, from Free On-line Dictionary of Computing Web site: http://wombat.doc.ic.ac.uk/foldoc/foldoc.cgi?metadata Nielsen, J. (2003 , June 30). Information Foraging: Why Google Makes People Leave Your Site Faster. Retrieved September 15, 2003, from Jakob Nielsen’s Alertbox Web site: http://www.useit.com/alertbox/20030630.html Platform for Internet Content Selection (PICS). (2003, January 2). Retrieved September 17, 2003, from W3C.org Web site: http://www.w3.org/PICS/ Resource Description Framework (RDF). (2003, August 5). Retrieved September 17, 2003, from W3C.org Web site: http://www.w3.org/RDF/