Digital Libraries INFO 653

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Digital LibrariesINFO 653 Metadata Week 3Xia
LinCollege of Information Science and
TechnologyDrexel University
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This Week

• Three Topics
• Metadata
• XML/RDF
• Shape of Knowledge

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Metadata

• Metadata are data about data
• to describe features of the data (digital
  objects)
• Content what the object is about
• Context who, what, why, where and how aspects
  associated with the object
• Structure associations within or among
  individual objects

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(ALA) Committees Definition

• Metadata are structured, encoded data that
  describe characteristics of information-bearing
  entities to aid in the identification, discovery,
  assessment, and management of the described
  entities.

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Why Metadata?

• Metadata is key to ensuring that resources will
  survive and continue to be accessible into the
  future.
• Standards
• Structures and organization
• Content and context

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Why are metadata important to Digital Libraries?

• Digital libraries are about everything metadata
  stand for
• identification,
• discovery,
• assessment,
• management
• preservation
• of digital objects.

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Functions of Metadata

• To help organize resources
• Once described, digital objects would be much
  easier to organize.
• To facilitate resource discovery
• To facilitate interoperability
• To support digital identification
• To support archiving and preservation

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Standardization!!

• Metadata make it possible to adopt standards
  within specific domains or use.
• This makes it easy to exchange digital objects
  described in distributed servers or different
  organizations.
• It also supports more specific description for
  different types of objects with specific metadata
  (for images, videos, or others).

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Types of Metadata

• Descriptive
• Title, abstract, keywords
• Administrative
• Who and how it is created
• Right management
• Structural
• Relationships among objects

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Attributes of Metadata

• Source of metadata
• Nature of metadata
• Structure
• Conform to a standard
• Semantics
• Controlled vocabulary or not
• Level
• How details the metadata are.

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Metadata Schemas

• A metadata schema provides a formal structure
  designed to identify the knowledge structure of a
  given discipline and to link that structure to
  the information of the discipline through the
  creation of an information system that will
  assist the identification, discovery and use of
  information within that discipline.

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• Schemas are sets of metadata elements to describe
  a resource
• Semantics definitions and meanings of the
  metadata elements
• Contents values given to metadata elements
• Content rules what values should be used, how
  the values should be formulated.

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Dublin Core

• Dublin Core is the most widely used metadata on
  the web
• Simple
• Practical
• Based on library science foundation
• Have a good abstract model
• Open standard with a good organization behind it.

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Dublin Core Elements
Creator
Language
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A DC example

• lt?xml version"1.0"?gt
• ltmetadata xmlns"http//example.org/myapp/"
  xmlnsxsi"http//www.w3.org/2001/XMLSchema-instan
  ce" xsischemaLocation"http//example.org/myapp/
  http//example.org/myapp/schema.xsd"
  xmlnsdc"http//purl.org/dc/elements/1.1/"gt
• ltdctitlegt UKOLN lt/dctitlegt
• ltdcdescriptiongt UKOLN is a national focus of
  expertise in digital information management. It
  provides policy, research and awareness services
  to the UK library, information and cultural
  heritage communities. UKOLN is based at the
  University of Bath. lt/dcdescriptiongt
• ltdcpublishergt UKOLN, University of Bath
  lt/dcpublishergt ltdcidentifiergt
  http//www.ukoln.ac.uk/ lt/dcidentifiergt
  lt/metadatagt

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DC DOT

• http//www.ukoln.ac.uk/metadata/dcdot/
• Exercises
• Add Dublin Core Headings to your three review
  papers.

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DCMI Metadata Terms

• elements,
• element refinements
• Abstract/accessRight/accessMethod
• encoding schemes,
• DDC/LCC/NLM
• LCSH/MeSH/TGN
• Point/RFC1766
• Vocabulary terms
• Collection/Dataset/Event/Image/InteractiveResource
  /
• MovingImage/PhysicalObject/Service/Software/sound/
  Text

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Discussion

• What is the relationship between
• Metadata and thesaurus?
• Metadata and cataloging?
• Metadata and FRBR?

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FRBR

• Functional Requirements for Bibliographic Records
• A conceptual modeling for Bibliographic Universe

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Group 1
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Group 2
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(No Transcript)
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Discussion

• What is the distinction between the content and
  metadata?
• Metadata is used what you know to find what you
  dont know.
• With search engines, you can use a line from the
  book to get the bibliographic record of the book,
  thus the content is the metadata of the book?

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Discussion

• Whats the distinction between metadata and
  social tagging?
• Whats the new shape of knowledge?

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Moving from Trees to piles of leaves?

• David Weinberger proposes that in the digital
  world, the most "natural," efficient and
  responsive way to manage knowledge is to create
  huge, distributed piles of leaves, each tagged
  with as much metadata as possible - including
  treating the content as metadata - and postponing
  until the last minute the taxonomizing of the
  information. What will be the social effects as
  we move from trees to piles of leaves?
• http//webcast.oii.ox.ac.uk/?viewWebcastID20051
  130_109

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XML

• XML stands for eXtensible Markup Language
• Designed to separate style, content, and context,
  and presentation in the web environment
• Designed to deploy content-specific tags for
  content indexing and retrieval.
• Designed as a subset of SGML

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Example

• lt?xml version"1.0" encoding"utf-8" ?gt
• ltbook isbn"0836217462"gt
• lttitlegtBeing a Dog Is a Full-Time Joblt/titlegt
• ltauthorgtCharles M. Schulzlt/authorgt
• ltcharactergt
• ltnamegtSnoopylt/namegt
• ltfriend-ofgtPeppermint Pattylt/friend-ofgt
• ltsincegt1950-10-04lt/sincegt
• ltqualificationgtextroverted
  beaglelt/qualificationgt
• lt/charactergt
• ltcharactergt
• ltnamegtPeppermint Pattylt/namegt
• ltsincegt1966-08-22lt/sincegt
• ltqualificationgtbold, brash and
  tomboyishlt/qualificationgt
• lt/charactergt
• lt/bookgt

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XML is an industry itself

• All the major software companies implemented some
  types of XML-related software
• XML-related standards are continually developed
  everyday.
• XSL Extensible Stylesheet Language
• XSLT -- Extensible Stylesheet Language
  Transformations
• XSLT enables and empowers interoperability
• Xlink -- XML Linking Language
• Assign meanings to links
• RDF Resource Description Framework

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XML Example (www.XML.com)

• lt?xml version"1.0"?gt
• ltartistinfogt
• ltsurnamegtModiglianilt/surnamegt
• ltnamegtAmadeolt/namegt
• ltborngtJuly 12, 1884lt/borngt
• ltdiedgtJanuary 24, 1920lt/diedgt
• ltbiographygt
• ltpgtIn 1906, Modigliani settled in Paris,
  where ...lt/pgt
• lt/biographygt
• lt/artistinfogt

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Example

• lt?xml version"1.0"?gt
• ltperiodgt
• ltcitygtParislt/citygt
• ltcountrygtFranceltcountrygt
• lttimeframe begin"1900" end"1920"/gt
• lttitlegtParis in the early 20th century (up to
  the twenties) lt/titlegt
• ltendgtAmadeolt/endgt
• ltdescriptiongt
• ltpgtDuring this period, Russian, Italian,
  ...lt/pgt
• lt/descriptiongt
• lt/periodgt

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• ltenvironment xmlnsxlink"http//www.w3.org/1999/x
  link"
• xlinktype"extended"gt
• lt!-- The resources involved in our link
  are the artist --gt
• lt!-- himself, his influences and the
  historical references --gt
• ltartist xlinktype"locator"
  xlinklabel"artist"
• xlinkhref"modigliani.xml"/gt
• ltinfluence xlinktype"locator"
  xlinklabel"inspiration"
• xlinkhref"cezanne.xml"/gt
• ltinfluence xlinktype"locator"
  xlinklabel"inspiration"
• xlinkhref"lautrec.xml"/gt
• ltinfluence xlinktype"locator"
  xlinklabel"inspiration"
• xlinkhref"rouault.xml"/gt
• lthistory xlinktype"locator"
  xlinklabel"period"
• xlinkhref"paris.xml"/gt
• lthistory xlinktype"locator"
  xlinklabel"period"
• xlinkhref"kisling.xml"/gt
• lt/environmentgt

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XML and Digital Libraries

• XML for Content Management
• Content indexing
• Precision retrieval
• Content customization/personalization
• XML for Information Publishing
• Information Sharing
• Publishers have been using SGML for a long time.
• SGMLs difficult to use
• Standards are not widely accepted
• Software is very limited.
• XML overcomes all these problems.

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Writing an XML Document

• XML document must be well formed
• A root element is required.
• Closing tags are required.
• Elements must be properly nested.
• Case matters.
• Entity references must be declared in a DTD or a
  schema.

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XML Document Headings

• lt?xml version"1.0" encoding"UTF-8"?gt
• lt?xml-stylesheet type"text/css"
  href"http//research.cis.drexel.edu/classes/info6
  53/XML/repository.css" ?gt
• ltrepository xmlnsxsi"http//www.w3.org/2000/10/X
  MLSchema-instance" xsinoNamespaceSchemaLocation"
  http//research.cis.drexel.edu/classes/info653/XML
  /DLRepository.xsd"gt

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XML document content

• lttitlegtNASA Image Exchangelt/titlegt
• ltsitegthttp//nix.nasa.gov/lt/sitegt
• ltmetadatagt
• ltrepository-namegtNASA Image Exchangelt/repository-n
  amegt
• ltcategorygt
• ltlabelgtCATEGORYlt/labelgt
• ltdatagtimageslt/datagt
• lt/categorygt

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Style Sheet

• repository displayblock font-sizelargecolorM
  aroon
• title displayblockfont-sizelargetext-alignce
  nter
• site displayblock text-aligncenter
• metadata floatrightclearrightwidth225pxbord
  erthin solid Tealpadding10px
• repository-name dislplayblockfont-sizemediumb
  ackgroundNavycolorYellow text-aligncenter
• label displayblockfont-sizemedium
• data displayblock font-sizesmallcolorblue
  positionrelative left9px
• descriptiondisplayblock
• review displayblock colorblack
• name displayblock text-alignright
  colorBlue fontsmall
• term displaynone

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Assignment 5

• convert your repository reviews (assignment 3)
  into XML
• Define a XML Schema for repository reviews (What
  tags should be used)
• Write the XML document
• Create a Cascading Style Sheets to control the
  view

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XML Scheme
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RDF

• RDF, the Resource Description Framework, is a
  framework for metadata.
• RDF describe a collection, or a group of
  resources
• interoperability of metadata
• machine understandable semantics for metadata

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The RDF Model

• Based on mathematical model
• Arc-node diagrams
• Web resources represented by nodes with URI
• Collections of properties known as descriptions

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A RDF Graph
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RDF Data model

• RDF describe contents as well as content
  relationships
• 1.There is a set called Resources.
• 2.There is a set called Literals.
• 3.There is a subset of Resources called
  Properties.
• 4.There is a set called Statements, each element
  of which is a triple of the form
• pred, sub, obj Where pred is a property (member
  of Properties), sub is a resource (member of
  Resources), and obj is either a resource or a
  literal (member of Literals).

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RDF Syntax Specification

• Resources
• All things being described by RDF expressions
  are called resources.
• Properties
• A property is a specific aspect,
  characteristic, attribute, or relation used to
  describe a resource.
• Statements
• A specific resource together with a named
  property plus the value of that property for that
  resource is an RDF statement.

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RDF Schemas

• RDF Schemas define
• available PropertyTypes within a particular
  metadata system
• structure
• allowable values
• semantics
• A Schema Definition Language is currently being
  defined by the W3C
• Use Namespace URIs for schema definitions

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RDF Applications

• resource discovery to provide better search
  engine capabilities
• cataloging for describing the content and content
  relationships available at a particular Web site,
  page, or digital library
• facilitate knowledge sharing and exchange
• describing collections of pages that represent a
  single logical "document"
• describing intellectual property rights of Web
  pages.

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RDF Example Open Directory Project

• ltRDF xmlnsr"http//www.w3.org/TR/RDF/"
• xmlnsd"http//purl.org/dc/elements/1.0/"
• xmlns"http//directory.mozilla.org/rdf"gt
• ltTopic rid"Top"gt
• lttag catid"1"/gt
• ltdTitlegtToplt/dTitlegt
• ltnarrow rresource"Top/Arts"/gt
• ltnarrow rresource"Top/Business"/gt
• ltnarrow rresource"Top/Computers"/gt
• .
• ltnarrow rresource"Top/Bookmarks"/gt
• lt/Topicgt

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• ltExternalPage about"http//www.homeideas.com/"gt
• ltdTitlegtHome Ideas Home Improvement Ideas for
  Kitchen, Bath, Yard and Garden, etc.lt/dTitlegt
• ltdDescriptiongtThe ultimate resource for home
  projects. Research projects using past issues of
  Today's Homeowner magazine, request free product
  literature, and link to over 700 industry
  websites.lt/dDescriptiongt
• lt/ExternalPagegt
• ltExternalPage about"http//www.housenet.com/"gt
• ltdTitlegtHouseNet.Comlt/dTitlegt
• ltdDescriptiongtHome improvement, Gardening,
  Decorating, Sewing, and Money Saving
  Information.lt/dDescriptiongt
• lt/ExternalPagegt

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use Dubin Core in RDF example

• ltrdfRDF xmlnsrdf"http//www.w3.org/TR/WD-rdf-sy
  ntax" xmlnsdc"http//purl.org/dc/elements/1.0/"
  gt
• ltrdfDescription about"http//www.ukoln.ac.u
  k/"gt
• ltdcTitlegt UKOLN UK Office for Library
  and Information Networking lt/dcTitlegt
• ltdcCreatorgt UKOLN Information Services
  Group lt/dcCreatorgt
• ltdcSubjectgt national centre network
  information support library community
  awareness research information services public
  library networking bibliographic management
  distributed library systems metadata resource
  discovery conferences lectures workshops
  lt/dcSubjectgt
• ltdcDescriptiongt UKOLN is a national
  centre for support in network information
  management in the library and information
  communities. It provides awareness, research and
  information services lt/dcDescriptiongt
• ltdcDategt 1998-02-17 lt/dcDategt
• ltdcFormatgt text/html lt/dcFormatgt
• lt/rdfDescriptiongt
• lt/rdfRDFgt