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CS 502: Computing Methods for Digital Libraries

Lecture 10 New Developments in XML: MathML, Namespaces, RDF. CS 502: Computing Methods for Digital Libraries. Administration. Net Library: Comments, feedback, experience -- to John Saylor CDs for rebuilding laptop software: available in Upson 308 Change to schedule:

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CS 502: Computing Methods for Digital Libraries

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  1. Lecture 10 New Developments in XML: MathML, Namespaces, RDF CS 502: Computing Methods for Digital Libraries

  2. Administration • Net Library: • Comments, feedback, experience -- to John Saylor • CDs for rebuilding laptop software: available in Upson 308 • Change to schedule: • Office hours -- Wednesday • Lecture on March 14 • Mid-term examination: • Wednesday, March 8, 7:30 to 8:30

  3. MathML • Objectives: • Encode mathematical material for teaching and scientific communication at all levels • Encode both mathematical notation and mathematical meaning • Facilitate conversion to and from other math formats, both presentational and semantic. e.g., TeX • Be suitable for a wide range of output formats, including Braille • Provide for extensibility • Be human legible, and simple for software to generate and process • Intended for use with both HTML and XML

  4. Presentation and Content Markup Example:a + b Presentation: <mrow> <mi>a</mi> <mo>+</mo> <mi>b</mi> </mrow> Content: <apply> <plus/> <ci>a</ci> <ci>b</ci> </apply>

  5. Presentation and Content Markup Example: (a + b)2 Presentation: <msup> <mfenced> <mrow> <mi>a</mi> <mo>+</mo> <mi>b</mi> </mrow> </mfenced> <mn>2</mn> </msup> Content: <apply> <power/> <apply> <plus/> <ci>a</ci> <ci>b</ci> </apply> <cn>2</cn> </apply>

  6. Annotations t   dx x 0 <apply> <int/> <bvar><ci>x</ci></bvar> <lowlimit><cn>0</cn></lowlimit> <uplimit><ci>t</ci></uplimit> <apply> <divide/> <cn>1</cn> <ci>x</ci> </apply> </apply> Content

  7. Annotations t   dx x 0 <mrow> <msubsup> <mo>&int;</mo> <mn>0</mn> <mi>t</mi> </msubsup> <mfrac> <mrow> <mo>&dd;</mo> <mi>x</mi> </mrow> <mi>x</mi> </mfrac> </mrow> Presentation

  8. Annotations <semantics> Content encoding <annotation-xml encoding="MathML-Presentation"> Presentation encoding </annotation-xml> </semantics>

  9. XML Namespaces • Namespaces: • Allow those who publish XML to explicitly indicate where their information is coming from • Avoids any confusion regarding the information's origin

  10. Using Namespaces • Examples: • <bk:title>Cheaper by the Dozen</bk:title> • <isbn:number>1568491379</isbn:number> • The tag consists of two parts: • namespace (in red) • name within namespace (in blue)

  11. Specifying Namespaces Example 1 <xhtml xmlns = "http://www.w3.org/1999/xhtml"> .... </xhtml>

  12. Specifying Namespaces Example 2 <?xml version="1.0"?> <!-- both namespace prefixes are available throughout --> <bk:book xmlns:bk = "http://loc.gov:books" xmlns:isbn = "urn:ISBN:0-395-36341-6"> <bk:title>Cheaper by the Dozen</bk:title> <isbn:number>1568491379</isbn:number> </bk:book>

  13. Resource Descriptions as Graphs "Shakespeare is the author of the play Hamlet." creator Hamlet Shakespeare type play

  14. RDF: Metadata Schemes • "Shakespeare is the author of the play Hamlet." • In the Dublin Core metadata scheme, this can be represented as: • ResourceProperty-typeValue • Hamlet ---> creator ---> Shakespeare • ---> type ---> play • A different metadata scheme, might use the term author in • place of creator, and the term type with a different meaning.

  15. Use of Namespace "Shakespeare is the author of the play Hamlet." dc:creator Hamlet Shakespeare dc:type play

  16. RDF: Metadata Schemes • Define a namespace for the metadata scheme • Basic XML • <creator>Shakespeare</creator> • <type>play</type> • With dc namespace • <dc:creator>Shakespeare</dc:creator> • <dc:type>play</dc:type>

  17. RDF: Identifying Resources • Suppose that Hamlet is referenced by the URL: • "http://hamlet.org/" • <rdf:description rdf:about = "http://hamlet.org/"> • .......... • </rdf:description>

  18. RDF: Full Record • Full RDF record, with XML mark-up: • <rdf:rdf> • <rdf:description rdf:about = "http://hamlet.org/"> • <dc:creator>Shakespeare</dc:creator> • <dc:type>play</dc:type> • </rdf:description> • </rdf:rdf>

  19. RDF: Namespace Information • Full RDF record, with Namespace Definitions: • <rdf xmlns = “http://www.w3.org/TR/WD-rdf-syntax#” • xmlns:dc = “http://purl.org/dc/elements/1.0/”> • <rdf:description rdf:about = "http://hamlet.org/"> • <dc:creator>Shakespeare</dc:creator> • <dc:type>play</dc:type> • </rdf:description> • </rdf>

  20. Complexity v. Acceptance • Markup • SGML was slow to gain acceptance because it is complex • HTML and the web gained acceptance because they were simple • XML is gaining acceptance steadily for structural mark-up, but has a long way to go • Style sheets • DSSSL has not been accepted because of complexity • CSS and XSL are slowly gaining acceptance, but have a long way to go

  21. Complexity v. Acceptance • Mathematics: • MathML is complex but mathematics is complex. It may succeed. • Metadata markup: • XML is becoming the standard for metadata. It is simple and intuitive. • RDF adds functionality, but a lot more complexity. • Namespaces: • Namespaces are a simple concept, but the notation adds a lot of complexity

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