Using XML, XSLT, and CSS in a Digital Library

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Using XML, XSLT, and CSS in a Digital Library

• Markup Transformations
• SGML to XML Conversions
• Metadata Schema Generation
• Robert Ferrer
• r-ferrer_at_uiuc.edu
• ASIS Annual Meeting 2000

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SGML to XML Conversions - Modular
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SGML to XML Conversions - Basic

• Empty tags ltemptygt to lt .. /gt
• lt?Processing Instructiongt to lt? ... ?gt
• CDATA to CDATA sections lt!CDATA gt
• Named entities remain unchanged - alpha
• lt!DOCTYPE ...gt refers to XML DTD containing only
  character entity definitions to Unicode points
  lt!ENTITY alpha 945gt

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SGML to XML Conversions - Linking

• Attributes to facilitate internal linking
• ltCITEREF REFID"bib5" idli_occurrence3 /gt
• External links represented as XLinks
• ltFIG NAMEF1 xlinktypesimple
  xlinkhreffig1.jpg xlinkshownew
  xlinkactuateuser /gt

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SGML to XML Conversions - Math

• SGML Math converted to MathML

Presentational MathML ltmath xmlnshttp//www.w3.o
rg/gt ltmsubsupgt
ltmrowgtltmigtalphalt/migtlt/mrowgt
ltmrowgtltmigtilt/migtlt/mrowgt
ltmrowgtltmogt-lt/mogtltmngt2lt/mngtlt/mrowgt
lt/msubsupgt lt/mathgt
ISO 12083 Math ltdformulagt ltggtalt/ggt
ltsupgt-2lt/supgt ltinfgtilt/infgt lt/dformulagt
Identify translate mathematical character
references Identify tokenize mathematical
content
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SGML to XML Conversions - Math

• Recognize transform mathematical markup
• ltxsltemplate matchdformulagt ltxslwhen
  test"sup or inf"gt
• ltxslfor-each select"childnode()"gt
• ltxslchoosegt
• ltxslwhen test"name(selfnode())'su
  p' and name(following siblingnode()1)'inf'"gt
• ltxslelement name"msubsup
  namespacehttp//www.w3.org/gt
• ltxslelement name"mrow
  namespacehttp//www.w3.org/gt
• ltxslapply-templates
  select"preceding-siblingnode()1"/gt
• lt/xslelementgt

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SGML to XML Conversions - TeX

• TeX converted to GIF images
• ltFORM NOTATION"TEX" HIDE"TRUE"gt
  (j_0-a_2')\,\rm mod\,P lt/FORMgtltuie name
  uie1 xlinktype"simple" xlinkhref"fig1.gif"
  xlinkshow"new" xlinkactuate"user /gt
• TeX converted into MathML
• IBM TechExplorer

(j_0-a_2')\,\rm mod\,P
ltmathgtltmogt(lt/mogtltmsubgt ltmrowgtltmigtjlt/migtlt/mrowgtltmr
owgtltmngt0lt/mngtlt/mrowgtlt/msubgtltmigtminuslt/migt ltmsub
supgtltmrowgtltmigtalt/migt lt/mrowgtltmrowgtltmngt2lt/mngt..
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SGML to XML Conversions - DTD

• XML DTD does not permit inclusions and exclusions
• SGMLlt!ELEMENT Article - - (front, body)
  (i.float)gt
• XMLlt!ELEMENT Article (front body
  i.float)gt
• XML DTD does not permit the connector
• XML DTD does not permit the use of mixed content
  models
• lt!ELEMENT Other ((author, journal) (PCDATA))gt

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Metadata - Usage

• Metadata Within the DLI Testbed
• Normalize key fields from different publisher
  DTDs to facilitate searching
• Provide common and easily displayable
  intermediate search results
• Add value in the form of links to cited or citing
  articles within the Testbed, external abstracts
  and indexes, etc.

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Metadata - Schema

• Resource Description Framework (RDF) provides
  standardized way to represent metadata using XML
• Encapsulates metadata elements
• Provides varying levels of granularity
• RDF container objects describe the relations
  between repeated metadata elements

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Metadata - Schema

• Dublin Core (DC) model is used to encapsulate all
  searchable metadata
• Provides the semantic framework for describing
  each object in the collectionContent Intellectu
  al Property InstantiationTitle Creator Date
  Subject Publisher FormatDescription Contributo
  r IdentifierType Rights LanguageSourceRel
  ationCoverage

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Metadata - Schema

• Extensive custom IDLI tags are included
• Offer a further level of granularity
• ltDCDescriptiongtltidliAbstractgtlt/DCDescriptiongt
• Search clients familiar with IDLI schema can
  achieve much greater precision
• Dublin Core Qualifiers (DCQ) substructure to
  replace many of the project-specific IDLI
  elements
• ltDCDescriptiongtltDCQAbstractgtlt/DCDescriptiongt

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Metadata - Schema
ltrdfseqgt ltrdfligt ltdcCreatorgt
ltidliauthor_namegtGiust, G. K.lt/idliauthor_namegt
ltidliorganization_namegtDepartment of
Electrical Engineering, Arizona State
Universitylt/idliorganization_namegt
lt/dcCreatorgt lt/rdfligt ltrdfligt
ltdcCreatorgt ltidliauthor_namegtSigmon,
T.W.lt/idliauthor_namegt
ltidliorganization_namegtDepartment of Computer
Science, Illinois State University
lt/idliorganization_namegt lt/dcCreatorgt
lt/rdfligt lt/rdfseqgt
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Metadata - Extracting

• Metadata is extracted from the base XML files
• Utilization of XML Header
• DTD is used to resolve entities
• XML-Stylesheet processing instruction
• Visual Basic application serves as parser
• Document Object Model (DOM)
• XSLT Style Sheets

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Metadata - Extracting

• Utilization of XSLT Style Sheets
• XSLT transformative features to generate base
  metadata file and forward citation fragment
• XSLT scripting features to generate elementsnot
  directly expressed in the document
• XSLT instantiation of ActiveX objects to test for
  links

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Metadata - Extracting

• Utilization of DOM
• Insert pseudo elements (e.g. bibliographic data)
• Search reference citations from the generated
  metadata object to insert forward references into
  other metadata files