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Metadata, Structured Documents, and XML

Metadata, Structured Documents, and XML. Metadata. Literally “data about data” “a set of data that describes and gives information about other data” ― Oxford English Dictionary. Metadata. How do we encode metadata? How do we encode metadata to support interoperability?.

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Metadata, Structured Documents, and XML

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  1. Metadata, Structured Documents, and XML

  2. Metadata • Literally “data about data” • “a set of data that describes and gives information about other data” ― Oxford English Dictionary

  3. Metadata • How do we encode metadata? • How do we encode metadata to support interoperability? Simple example: January 31, 2001 31 janvier 2001 2001-01-31 01-31-2001 31012001

  4. What is the Dublin Core? • A metadata standard for describing digital resources • An initiative to create a digital “library card catalog” for the Web • Dublin Core fields: (all optional) Title Creator Subject Description Publisher Contributor Date Type Format Identifier Source Language Relation Coverage Rights

  5. What’s a structured document? • A structured document is a document whose structure conforms to a certain set of rules • Data and metadata encoded in an interoperable manner

  6. What is XML? • XML = eXtensible Markup Language • XML is a standard for exchanging structured data • Provides standardization at the syntactic level • Does not provide “meaning” for the tags • XML is a standard recommended by the W3C

  7. Goals of XML • Easy to use • Easy to extend and adapt • Easy to write programs that use XML • Support a wide variety of applications • Should be human legible • Formal and concise

  8. The Basic Rules • XML is case sensitive • All start tags must have end tags • Elements must be properly nested • XML declaration is the first statement • <?xml version="1.0"?> • Every document must contain a root element • Attribute values must have quotation marks • <item id=“33905”> • Certain characters are reserved for parsing • &lt; = ‘<’

  9. XML Example • <class> <name>LBSC690</name> <instructor>Jennifer Golbeck</instructor> <department>LBSC</department></class>

  10. Benefits • Data is represented in a universal syntax • This allows any website to read the data • Makes the exchange of data easier

  11. RSS • RSS = Really Simple Syndication or Rich Site Summary • An XML format for distributing news headlines on the Web

  12. RSS Example <item> <title>Maryland’s Slots Commission Pressures Anne Arundel County</title> <link>http://www.newsline.umd.edu/blog/index.php/2009/ 11/12/maryland%e2%80%99s-slots-commission-pressures-anne-arundel-county/</link> <pubDate>Thu, 12 Nov 2009 23:48:41 +0000</pubDate> <dc:creator>rlorente</dc:creator> <description>Gambling in Anne Arundel County seemed so close Thursday, but yet so far away. The Video Lottery Facility Location Commission nearly voted Thursday on a motion to approve the proposal for a casino at the Arundel Mills shopping mall without zoning approval from the Anne Arundel County Council. The council has not approved a zoning plan</description> </item>

  13. And Others… • CML – chemical Markup Lang • CellML – biological models • BSML – bioinformatic sequences • MAGE-ML – Microarray Gene Expression • XSTAR – for archaeological research • XMLMARC – MARC in XML • AML – astronomy markup language • SportsML – for sharing sports data

  14. The next best thing since… • What’s the big deal about XML? • What does XML not do? • How do XML tags acquire meaning? • How do standards arise?

  15. What’s wrong with the Web? • It was meant for humans, not machines • The current Web contains only data, not knowledge • From Web of data to Web of knowledge • Difficult to • Aggregate/compare data across sites • Delegate complex tasks to “agents” • Formulate complex queries involving multiple constraints • …

  16. Web 2.0 • Tagging (“folksonomy”) • Blogging • Web services • Wikipedia

  17. Summary • Concepts covered: • Metadata • Structured Documents • XML • Semantic Web • Ontologies

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