A Roadmap for Implementing Dublin Core

1
A Roadmap for Implementing Dublin Core

• Douglas Campbell
• National Library of New Zealand Te Puna
  Matauranga o Aotearoa
• GOVIS Conference, 13 November 2003

2
Agenda

• What is it? Why is it useful? How do I use it?
  Resources

• Metadata
• Dublin Core
• DCMI
• Application Profile
• Registry
• NZGLS

• HTML meta tags
• XML
• Namespaces
• Encoding in XML
• Semantic Web
• RDF

3
With thanks to

• Andy Powell, UKOLN, University of Bath
• Rachel Heery, UKOLN, University of Bath
• Eric Miller, W3C World Wide Web Consortium
• Tom Baker, Fraunhofer-Gesellschaft
• Makx Dekker, DCMI
• Simon Phipps, IBM UK
• Adrienne Kebbell, National Library of New
  Zealand

4
Key

• Horizon watchers
• Implementers
• Geeks ya_gotta_luv_it

5
Metadata
6
Metadata What is it?

• Structured data about data
• Separate (eg. library catalogue card, phone book)
  or Embedded (eg. CIP, HTML META tags)
• Machine-generated or Human created (because
  machines dont always get it right)
• Resource Discovery Metadata enough
  information to be able to find things, often
  layered on top of various application-specific
  metadata

7
Metadata Why is it useful?

• Information about something you dont have in
  front of you
• Help reduce information overload from vast
  quantities of undifferentiated data

8
Dublin Core Roadmap
Resource
9
Dublin Core
10
Dublin Core What is it?

• Simple yet effective element set for describing
  a wide range of networked resources.
• Small language for making a particular class of
  statements about resources.
• Created by the best brains from around the world!

11
Dublin Core - What is it?

• Some terminology (see also the DC Abstract Model)
• Resource - anything covered by DCMIType
  listCollection, Dataset, Event, Interactive
  Resource, Moving Image, Physical Object, Service,
  Software, Sound, Still Image, Text
• Property - a specific aspect, characteristic,
  attribute, or relation used to describe a
  resource
• Record - some structured metadata about a
  resource comprising one or more properties and
  their associated values
• DC defines a set of elements to use as properties

12
Dublin Core Why is it useful?

• Better searching, especially across unlike
  sources
• Answers the question what elements should I have
  in my metadata?
• Its practical
• Simplicity of creation and maintenance
• Commonly understood semantics
• International scope
• Extensibility

13
Dublin Core Why is it useful?

• Its a standard
• ANSI/NISO Z39.85 - US standard, October 2001
• ISO 15836 international standard, April 2003
• Dominant standard for cross-discipline resource
  discovery on Internet
• Standards arent about making it hard but about
  allowing mix-and-match modularity
• Interoperable - its naïve to think youre
  isolated from the global environment

14
Dublin Core Why is it useful?

• Resource Discovery adds high-level cross-domain
  layer so can search across unrelated data, then
  dig down into richer metadata

MARC
DCQ
Encoded Archival Description
NZGLS
DUBLIN CORE
National Library of New Zealand Metadata
Standards Framework, 2000
15
Dublin Core How do I use it?
15 core elements what you need to describe
something
16
Dublin Core Roadmap
Description
Element Value
Resource
Value
17
Dublin Core How do I use it?

• Examples of how to implement DC records
• Create directly into a DC-based systemeg. use
  HTML meta tagsor create/edit DC records in a
  database
• Crosswalkconvert existing metadata records into
  DC requires a mapping from your existing fields
  to DC elements
• Expose your metadata to look like DC (like
  crosswalk but in real time)eg. OAI harvest-able
  interface which converts your proprietary data
  into DC (only when it is requested)

18
Dublin Core How do I use it?

• Qualifiers
• Allow more precision to be specified
• 1. Refinements narrow the meaning (never
  extend), eg. Date created, Date modified
• 2. Encoding Schemes give context
• Controlled vocabulary, eg. list of country codes
• Formal notation (formatting rules), eg date
  format
• Are optional the Dumb down principle means a
  user can strip qualifiers leaving just the Core

19
Dublin Core Roadmap
DCMES
Description
Element Name
Element Value
Resource
Name
Value
20
Dublin Core How do I use it?

• Matapihi a Dublin Core success story
• National Digital Forum pilot for
  2004ndf.natlib.govt.nz
• Gateway to five online digital image collections
  Alexander Turnbull Library, Auckland and
  Christchurch City Libraries, Auckland Art
  Gallery, and Otago Museum
• Dublin Core metadata stored centrally, click-thru
  to the images and detailed metadata stored on
  each organisations website
• Similar to the PictureAustralia service

21
Dublin Core How do I use it?
Matapihi
DC MetadataDC MetadataDC Metadata
DC MetadataDC MetadataDC Metadata
DC MetadataDC MetadataDC Metadata
Websites
DC MetadataDC MetadataDC MetadataOther
MetadataOther MetadataOther MetadataOther
Metadata
DC MetadataDC MetadataDC MetadataOther
MetadataOther MetadataOther MetadataOther
Metadata
DC MetadataDC MetadataDC MetadataOther
MetadataOther MetadataOther MetadataOther
Metadata
22
Dublin Core Resources

• Dublin Core usage guidehttp//www.dublincore.org/
  documents/usageguide/
• DC grammar/definitionshttp//dublincore.org/usage
  /documents/principles/http//dublincore.org/usage
  /terms/
• Current DC elements and qualifiershttp//dublinco
  re.org/documents/dcmi-terms/
• Dubline Core Abstract Model proposalhttp//www.
  ukoln.ac.uk/metadata/dcmi/abstract-model/
• National Library of New Zealand Metadata
  Standards Frameworkhttp//www.natlib.govt.nz/en/w
  hatsnew/4initiatives.htmlmeta

23
DCMI
24
DCMI What is it?

• Dublin Core Metadata Initiative
• Organization dedicated to promoting the
  widespread adoption of interoperable metadata
  standards and developing specialized metadata
  vocabularies for describing resources that enable
  more intelligent information discovery systems.
• Since 1995

25
DCMI Why is it useful?

• A model of open participation
• International, multilingual, cross-industry,
  cross-profession
• Anyone can join/contribute
• Aim for consensus
• Full of helpful, knowledgeable, passionate
  people!

26
DCMI How do I use it?
Board of Trustees (7)
AdvisoryBoard (41)
UsageBoard (9)
Directorate (2)
Special Interest Groups (6)
27
DCMI How do I use it?

• Process
• Proposal to DC-General (anyone can do this)
• Working Group may discuss/develop further
• Final proposal to DC-General for comments
• Usage Board reviews (for usefulness, clarity of
  definition, overlap with existing terms)
• Gets Recommended status (or rejected)
• Status levels
• Recommended
• Conforming (if only applies to certain domains)
• Obsolete
• Registered (encoding schemes)

28
DCMI How do I use it?

• Down-under DCMI affiliate DC-ANZ
• DC-ANZ Support network and forum for metadata
  users in Australia and New Zealand
• Locally-focussed guides, conferences, education,
  translations, schema development, etc.
• MetaMatters clearinghouse http//www.dc-anz.org/m
  etamatters/
• Listserv forum for down-under localsDC-ANZ-subscr
  ibe_at_DC-ANZ.org

29
Dublin Core Roadmap
DCMES
Description
Element Name
Element Value
Refinement
Scheme
Lang
Resource
Name
Value
Refinement
Scheme
Lang
30
DCMI - Resources

• About DCMIhttp//dublincore.org/about/
• Usage Board Administrative Processeshttp//dublin
  core.org/usage/documents/process/
• DC Working Groupshttp//dublincore.org/groups/
• DC Working Groups mailing list archiveshttp//www
  .jiscmail.ac.uk/mailinglists/a-z/d.htm
• DC-ANZ Australia New Zealand
  supporthttp//www.dc-anz.org/

31
Application Profile
32
Application Profile What is it?

• An element set optimised for a particular local
  application. It may include terms (metadata
  elements) drawn from one or more element sets.
• Declaration (documentation) of usage reusing
  terms already defined elsewhere or using terms
  from a local element set.
• Does not re-declare elements defined by others
• Eg. My project uses a to qualify b, etc...

33
Application Profile Why is it useful?

• Allows metadata layering to be interoperable
  with other sets but also have additional
  complexity for local needs
• Solves the tension between alignment and
  differentiation
• Extensibility isnt new, eg
• MIME types image/jpeg image/gif image/...
• MARC local tags9xx xx9

34
Application Profile How do I use it?

• Element Set
• Declares new terms
• Defines identifiers, definitions, and comments
• Standalone

• Application Profile
• Declares terms to use together in a particular
  application or domain
• Refines usage requirements
• Re-uses terms from elsewhere

35
Dublin Core Roadmap
DCMI community
DCMES
Description
Element Name
Element Value
Refinement
Scheme
Lang
Resource
Name
Value
Refinement
Scheme
Lang
Value
36
Application Profile How do I use it?

• Simple DC vs Qualified DC vs Application Profile
• If you use DC terms other than just the 15 core
  elements, you are using Qualified DC
• If you use more than the DC defined qualifiers
  (ie. the element refinements and encoding schemes
  defined in DC Terms), you are using an
  application profile

37
Application Profile How do I use it?

• Process
• Define metadata requirements
• Select most appropriate existing standard
  metadata element set
• Where possible use existing standard elements for
  locally required elements, possibly narrowing
  semantics and adding local rules and encoding
  schemes
• Define remaining elements in private namespace

38
Application Profile How do I use it?

• Application Profile declaration
• Terms used plus sources
• Obligation of use, eg. mandatory, recommended,
  optional
• Any refinements in definition for terms from
  external sources
• Encoding schemes to use
• Other rules for content
• CEN AP guidelines are a good place to start
• Register your AP with a registry
• Health warning not for the faint of heart!

39
Application Profile How do I use it?

• Beware the re-declaring trap!
• Suggest how externally defined terms should be
  used, but do not re-declare what the term means
• Why not? Any change in scope or meaning of a term
  means it is no longer interoperable
• Aim confident we can extract the terms belonging
  to an external set and the data will comply with
  the external set
• Adopt not adaptEncourage diversity but limit
  divergence

40
DC metadata use in National Library of NZ
Picture Australia
MARC
Matapihi
ISAD(G)
DescriptiveRecords
Govt Portal
Discover
Digital Archive
41
DC metadata use in the National Library

• Dublin Core metadata does work as a core in
  multiple contexts
• Discovered the DC layer must be pure to work in
  multiple contexts i.e. strictly follow DCMI
  recommendations and international best-practice

42
Application Profile - Resources

• DC Usage Board Review of Application
  Profileshttp//dublincore.org/usage/documents/pro
  files/
• Ariadne journal article, September
  2000http//www.ariadne.ac.uk/issue25/app-profiles
  /
• CEN Guidelines for Application Profiles (CWA
  14855)http//www.cenorm.be/cenorm/businessdomains
  /businessdomains/informationsocietystandardization
  system/applyingtechnologies/meta-data(dublincor
  e)workshop/mmi-dublincoreworkshop.asp
• DC-Libraries Application Profile
  proposalhttp//dublincore.org/documents/library-a
  pplication-profile/
• DC-Gov Application Profile (in development)
• DC-Ed Application Profile (in development)

43
Application Profile - Resources

• AGLS ex Australian Government Locator Service
  http//www.naa.gov.au/recordkeeping/gov_online/ag
  ls/summary.html
• NZGLS NZ Government Locator Servicehttp//www.e
  -government.govt.nz/nzgls/index.asp
• E-GMS UK Government Metadata Standardhttp//www
  .govtalk.gov.uk/interoperability/metadata.asp
• RSLP Collection Descriptionhttp//www.ukoln.ac.uk
  /metadata/rslp/
• Digital Resource Description (in
  development)http//www.natlib.govt.nz/dr/drd.html
  

44
Registry
45
Registry What is it?

• A tool for managing shareable data - a
  comprehensive, authoritative source of reference
  information about data
• An index of terms
• Multiple schemas accessible from one view
• Links to definitions stored externally,
  orharvests into a central utility
• Still fairly new (DC Registry up Sept 2002)

46
Registry Why is it useful?

• Increase reuse of existing terms (rather than
  having to reinvent them)
• Provides implementation experience to assist
  schema development
• Able to obtain reliable and trusted information
  about schemas
• Improve interoperability
• Implementors use standards in pragmatic ways-
  standards are published but local
  adaptations/extensions are not widely available

47
Registry How do I use it?

• Search registry to identify element sets to use
  in an Application Profile
• Disclose your local element sets and Application
  Profiles in appropriate registry
• DCMI Registry
• Phase 1 offers mutlilingual search over DC
  elements, terms, DCMI Type
• Future phases will include registering encoding
  schemes, a machine-readable interface for
  validation, and a distributed registry model

48
Dublin Core Roadmap
DCMI community
DCMES
Description
Element Name
Element Value
Refinement
Scheme
Lang
Resource
Name
Value
Refinement
Scheme
Lang
Other Elements
Name
Value
Refinement
Scheme
Lang
Application Profile
49
Registry - Resources

• The DCMI Registryhttp//dublincore.org/dcregistry
  /
• DC Registry Working Grouphttp//dublincore.org/gr
  oups/registry/
• Ariadne article Registry for the Semantic
  Webhttp//www.dlib.org/dlib/may02/wagner/05wagne
  r.html
• DESIRE Metadata Registryhttp//desire.ukoln.ac.uk
  /registry
• ISO/IEC 11179 - data elements definitionshttp//w
  ww.iso.org/iso/en/CatalogueListPage.CatalogueList?
  ICS135ICS240

50
NZGLS
51
NZGLS What is it?

• New Zealand Government Locator Service
• Dublin Core based Application Profile for
  creating discovery level metadata in the New
  Zealand Government sector
• Originally derived from AGLS (Australia)
• v1.0 Apr 2001, v2.0 in Aug 2001, v2.1 soon
• State Services Commission is the steward,
  Archives New Zealand acts as custodian,Nationa
  l Library acts as custodian for the two custom
  developed thesauri (SONZ and FONZ)

52
NZGLS Why is it useful?

• Agreement on how to describe resources using
  Dublin Core within NZ Government agencies
• Better Government-wide resource discovery (e.g.
  in the govt.nz portal) as the metadata is more
  consistent
• Tackles describing services as well as documents
• Cabinet enourages NZGLS compliance in the State
  sector and local authorities to improve
  accessibility

53
NZGLS How do I use it?

• It is for resource discovery (use other metadata
  schemas for more detailed interactions), eg.
• www.govt.nz portal
• inter-agency searching
• Intranet
• Creation
• Metalogue tool (for portal)
• HTML meta tags
• XML or RDF/XML data
• Your own database (eg. intranet or CMS)

54
NZGLS How do I use it?

• In relation to Dublin Core
• four additional elements plus extra refinements
• additional vocabularies and encoding schemes
• rules and guidelines for best practices
• Five elements are defined differently in DC and
  NZGLS so to comply with both schemas those
  elements need to be repeated
• However version 2.1 of NZGLS will start
  re-aligning more with Dublin Core

55
NZGLS Resources

• NZGLS homehttp//www.e-government.govt.nz/nzgls/
• Cabinet decision on use, March 2002http//www.dpm
  c.govt.nz/cabinet/circulars/co02/3.html
• NZGLS compliance study, December
  2001http//www.e-government.govt.nz/docs/nzgls-co
  mpliance-study/

56
Syntax for encoding metadata

• Instatiate/encode abstract DC data using an
  appropriate syntax
• HTML
• XML
• RDF

57
Dublin Core Roadmap
DCMI community
Syntax - HTML/XML/RDF
DCMES
Description
Element Name
Element Value
Refinement
Scheme
Lang
Resource
Name
Value
Refinement
Scheme
Lang
Other Elements
Name
Value
Refinement
Scheme
Lang
Registry
Application Profile
58
HTML encoding
59
HTML encoding What is it?

• DC Record describing an HTML document embedded
  inside the actual HTML document itself (dont
  usually embed a record about something else)
• Uses the ltmetagt tags in HTML (in ltheadgt)
• These days its best to use XHTML for
  future-proofing

60
HTML encoding Why is it useful?

• Easy to create
• Easy to harvest
• Metadata wont get lost its attached to the
  resource!
• Downsides
• limit to the richness you can show (compared to
  XML or RDF)
• you can only describe one resource
• harder to do central maintenance/QA

61
HTML encoding How do I use it?

• Attributes in the ltmetagt tag
• Name (element/refinement name)
• Content (data value)
• Lang (language of data value, not the resource)
• Scheme (encoding scheme for data value)
• ltmeta nameDC.element.refinement
  contentvalue string langvalue
  string language schemeencoding
  scheme /gt

62
HTML encoding How do I use it?

• Examples
• ltmeta nameDC.subject contentfruit /gtltmeta
  nameDC.subject contentcake /gt
• ltmeta nameDCtitle langen
  valueAbout New Zealand /gtltmeta
  nameDCtitle langmi
  valueM333 Aotearoa /gt
• ltmeta nameDC.date.created
  content2002-02-28 schemeW3CDTF /gt

63
HTML encoding How do I use it?

• Notes
• Encode multiple values with multiple ltmetagts
• Values in attributes (eg. content) are CDATA
• Must be from the document character set (ie.
  text)
• Some characters are escaped (eg. amp lt gt
  etc)
• Current best practice is
• Elements and refinements start with lower case
  letter
• Encoding schemes start with an upper case letter

64
HTML encoding How do I use it?

• Notes
• Can use full-stop or colon, ie. these are
  equivalent
• ltmeta nameDCTERMS.Audience contentparents
  /gt
• ltmeta namedctermsaudience contentparents
  /gt
• Use DC element names, refinements, and encoding
  schemes as term name appears in the current
  list http//dublincore.org/documents/dcmi-terms/
  

65
HTML encoding How do I use it?

• Namespace prefix mixing with other elements
• Prefixes indicate source for each term, link to
  the reference using ltlinkgt tag
• ltlink relschema.DC hrefhttp//purl.org/dc/ele
  ments/1.1/ /gt
• ltlink relschema.DCTERMS hrefhttp//purl.org/d
  c/terms/ /gt
• ltlink relschema.NZGLS hrefhttp//www.e-g
  overnment.govt.nz/nzgls/standard/2.0/ /gt
• ltmeta nameDC.title contentE- Government /gt
• ltmeta name"DC.type.aggregationLevel"
  content"collection" /gt
• ltmeta nameDCTERMS.audience contentall /gt
• ltmeta nameNZGLS.function schemeFONZ
  contentstrategic policymaking /gt

66
HTML encoding How do I use it?

• XHTML considerations
• ltmetagt tags are empty tags so require terminating
  slash /gt at end
• Use xmllang instead of just lang attribute
  in XHTML 1.1
• XHTML 2.0 in Working Draft - may be some changes
  to ltmetagt tag, but DCMI are in discussion with
  the W3C

67
HTML encoding - Resources

• Encoding Dublin Core Metadata in
  HTMLhttp//www.ietf.org/rfc/rfc2731.txt
• Expressing Qualified Dublin Core in HTML/XHTML
  meta elementsproposed recommendationhttp//dub
  lincore.org/documents/dcq-html/
• W3C HTML/XHTML specificationshttp//www.w3c.org/M
  arkUp/

68
XML
69
XML What is it?

• Extensible Markup Language
• A markup language for structured information.
• A subset of SGML (Standardized General Markup
  Language), richer than HTML.
• The new CSV
• Think of as a grammar (establishing rules for new
  formats) rather than a language
• Its just a tool, it wont save the world by
  itself!

70
XML Why is it useful?

• Content and presentation are separated

71
(No Transcript)
72
ltHTMLgt ltHEADgtltTITLEgtPavlova Recipelt/TITLEgtlt/HEAD
gt ltBODYgt ltIMG SRCcake.jpg
ALIGNrightgt ltH2 ALIGNcentergtPavlovalt/H1
gt ltIgtLight meringue and cream cake with a
marshmallow-like centre, named after the
famous ballerina. Originated in New Zealand in
the 1920s. lt/Igt ltH4gtIngredientslt/H4gt
ltTABLE CELLPADDING5gt ltTRgt
ltTDgt3 egg whiteslt/TDgt ltTDgt1
teaspoon vinegarlt/TDgt ltTDgt3
tablespoons cold waterlt/TDgt lt/TRgt
ltTRgt ltTDgt1 teaspoon vanilla
essencelt/TDgt ltTDgt1 cup castor
sugarlt/TDgt ltTDgt3 teaspoons
cornflourlt/TDgt lt/TRgt lt/TABLEgt
HTML
73
lt?xml version1.0?gt lt!DOCTYPE RecipeML SYSTEM
RecipeML.dtdgt ltRecipeMLgt ltrecipegt
lttitlegtPavlovalt/titlegt ltsourcegtEdmonds
Cookbooklt/sourcegt ltdescriptiongtLight
meringue and cream cake with a marshmallow-like
centre, named after the famous ballerina.
Originated in New Zealand in the 1920s.
lt/descriptiongt ltingredient
quantity3gtegg whitelt/ingredientgt
ltingredient quantity1 measureteaspoongtvinega
rlt/ingredientgt ltingredient quantity3
measuretablespoongtcold
waterlt/ingredientgt ltingredient quantity1
measureteaspoongtvanilla
essencelt/ingredientgt ltingredient
quantity1 measurecupgtcastor
sugarlt/ingredientgt ltingredient quantity3
measureteaspoongtcornflourlt/ingredientgt
ltinstructiongtBeat ltingredientgtegg
whiteslt/ingredientgt until
stiff.lt/instructiongt ltinstructiongtAdd
ltingredientgtcold waterlt/ingredientgt and beat
again.lt/instructiongt
XML
74
XML Why is it useful?

• Though still use HTML for delivery/presentation

Server
Server
XML
XSL
XML
XSL
HTML
Browser
IE5
HTML
75
lt?xml version"1.0"?gt ltxslstylesheet
version"1.0 xmlnsxsl"http//www.w3.o
rg/1999/XSL/Transform"gt ltxsltemplate
match/RecipeML/recipegt ltHTMLgt ltHEADgt
ltTITLEgtltxslvalue-of select"title"/gtRecipelt/TITLE
gt lt/HEADgt ltBODYgt ltIMG SRC"image/url"
ALIGN"right"/gt ltH2 ALIGN"center"gtltxslvalue
-of select"title"/gtlt/H2gt ltIgtltxslvalue-of
select"description"/gtlt/Igt
ltH4gtIngredientslt/H4gt ltULgt ltxslfor-each
selectingredientgt
ltLIgtltxslvalue-of select"_at_quantity"/gt
ltxslvalue-of select"_at_measure"/gt
ltxslif select"_at_quantitygt1"gtslt/xsl
ifgt ltxslvalue-of
select"."/gt lt/LIgt
XSLT
76
XML Why is it useful?

• Is both human-readable and machine-readable and
  thats by any machine (Windows/Mac/Unix)
• Is structured and self-describing can be
  re-purposed
• Extensible so wont become obsolete is now a
  family of technologies based on the XML format
  (eg. XHTML, XPATH, XLINK, XSL Schema, DOM, XQL,
  SOAP)
• Widely used (5th birthday on 10 Feb 2003)

77
XML Why it is useful

• The significance of XML
• Platform-centric system components are complex
  and inter-dependent so if one fails, others will
  too.
• XML is the last piece in the solution-centric
  computing model jigsaw. This means you can have
  just a business relationship with customers
  without having to have a technical relationship
  too!

Simon Phipps
78
Program
Data
Network
Delivery
Component
Platform-centric
Solution-centric
Delivery Network Program Data
Proprietary mainframe/terminalProprietary
server/client Proprietary Proprietary Proprietary
Web model TCP/IP Java XML
79
XML Resources

• W3C XMLhttp//www.w3.org/XML/http//www.w3.org/X
  ML/Activity
• xml.com

80
Namespace
81
Namespace What is it?

• In the context of XML
• A collection of names, identified by a URI
  reference
• (URIs (Uniform Resource Identifiers) are short
  strings that refer to resources ie. URLs and
  URNs)
• May appear in a qualified name which has
• Namespace prefix (associated with a URI)
• Local part
• mystuff where myhttp//here.com/this/
  means http//here.com/this/stuff

82
Namespace Why is it useful?

• The same terms in different element sets can be
  identified separately, eg. mynow ltgt yournow
• By making local terms unique globally (by adding
  a namespace) they can be shared unambiguously,
  making it possible to share semantics.

83
Namespace How do I use it?

• lt?xml version"1.0" ?gt
• ltmetadata xmlnsdc"http//purl.org/dc/elements/1.
  1/"
• xmlnsdcterms"http//purl.org/d
  c/terms/"
• xmlnsnzgls"http//www.e-govern
  ment.govt.nz/"gt
• ltdctitlegtE-Governmentlt/dctitlegt
• ltnzglsaggregationLevelgtcollectionlt/nzglsaggreg
  ationLevelgt
• ltdctermsaudiencegtalllt/dctermsaudiencegt
• ltnzglsfunctiongtltnzglsFONZgtstrategic
  policymakinglt/nzglsFONZgt
• lt/nzglsfunctiongt
• lt/metadatagt

84
Namespace - Resources

• Namespaces in XML W3 recommendationhttp//www.w
  3.org/TR/REC-xml-names/
• Naming and Addressing URIs, URLs,
  ...http//www.w3.org/Addressing/
• Namespace Policy for the DCMIhttp//www.dublincor
  e.org/documents/dcmi-namespace/

85
Encoding in XML
86
Encoding in XML What is it?

• RDF/XML is DCMIs preferred XML encoding, but
  there are also guidelines for encoding DC in XML
• DCMI maintains a list of XML schemas in use

87
DC XML guidelines

• Use XML SchemasImplementors should base their
  XML applications on XML Schemas rather than XML
  DTDs
• Use XML NamespacesImplementors should use XML
  Namespaces to uniquely identify DC elements,
  element refinements and encoding schemes

88
DC XML guidelines

• Data in elements, not attributesImplementors
  should encode properties as XML elements and
  values as the content of those elements
• Use lowercase element namesThe property names
  for the 15 DC elements should be all lower-case
• Repeat elements for multiple valuesMultiple
  property values should be encoded by repeating
  the XML element for that property

89
DC XML guidelines

• lt?xml version"1.0"?gt
• ltmetadata xmlns"http//example.org/myapp/"
  xmlnsxsi"http//www.w3.org/2001/XMLSchema-instan
  ce" xsischemaLocation"http//exa
  mple.org/myapp/ http//example.org/myapp/schema.
  xsd" xmlnsdc"http//purl.org/dc/elements/1.1/"gt
• ltdctitlegtPapers Pastlt/dctitlegt
• ltdcdescriptiongtPapers Past showcases selected
  19th century New Zealand newspapers and
  periodicals.lt/dcdescriptiongt
• ltdcpublishergtNational Library of New
  Zealandlt/dcpublishergt
• ltdcidentifiergthttp//paperspast.natlib.govt.nz
  /lt/dcidentifiergt
• lt/metadatagt

90
DC XML guidelines

• Refinements as standalone XML elements Element
  refinements should be treated in the same way as
  other properties
• ltdctermsavailablegt2002-06lt/dctermsavailablegt ?
• rather than
• ltdcdate refinement"available"gt2002-06lt/dcdategt
  ?
• ltdcdate type"available"gt2002-06lt/dcdategt ?
• ltdcdategt
• ltdctermsavailablegt2002-06lt/dctermsavailab
  legt
• lt/dcdategt ?

91
DC XML guidelines

• Encoding schemes use xsitype attributeEncoding
  schemes should be implemented using the
  'xsitype' attribute of the XML element for the
  property
• Use the DC name not labelElement refinements
  and encoding schemes should use the names
  specified in the DC Qualifiers recommendation
  (listed as the 'Name', not as the 'Label')
• Use xmllang for data value languageWhere the
  language of the value is indicated, it should be
  encoded using the 'xmllang' attribute

92
DC XML guidelines

• 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/xmlns
  dcterms"http//purl.org/dc/terms/"gt
• ltrecordgt
• ltdctitlegtPapers Pastlt/dctitlegt
• ltdcdescriptiongtPapers Past showcases selected
  19th century New Zealand newspapers and
  periodicals.lt/dcdescriptiongt
• ltdcdescription xmllangmi"gtAnei e
  whakatairangatia ake ana 275nei n363pepa o
  mua n333 Niu T299reni, i mahue mai ai i te
  rau tau 1800-1899.lt/dcdescriptiongt

93
DC XML guidelines

• ltdcpublishergtNational Library of New
  Zealandlt/dcpublishergt
• ltdctermsavailable xsitype"dctermsW3CDTF"gt20
  01-08-22 lt/dctermsavailablegt
• ltdcformat xsitype"dctermsIMT"gtimage/tifflt/d
  cformatgt
• ltdcidentifier xsitype"dctermsURI"gthttp//pa
  perspast.natlib.govt.nz/ lt/dcidentifiergt
• ltdctermstemporal xsitypedctermsW3CDTFgt184
  0/1900 lt/dctermstermporalgt
• ltdctermsspatial xsitypedctermsISO3166gtNZlt
  /dctermsspatialgt
• lt/recordgt
• lt/metadatagt

94
DC XML - Resources

• Guidelines for implementing Dublin Core in
  XMLhttp//www.dublincore.org/documents/dc-xml-gui
  delines/
• DCMI term declarations in XML schema
  languagehttp//www.dublincore.org/schemas/xmls/
• Open Archives Initiative Protocol for Metadata
  Harvesting XML examplehttp//www.openarchives.o
  rg/OAI/openarchivesprotocol.html

95
Semantic Web
96
Semantic Web What is it?

• The abstract representation of data on the World
  Wide Web
• An extension of the current web in which
  information is given well-defined meaning, better
  enabling computers and people to work in
  cooperation
• Information is maintained in structured form
  rather than in natural language

97
Semantic Web Why is it useful?

• The next simple technology that revolutionises
• IP - allowed computers to talk to each other
  giving us the Internet
• URI - allowed resources to be uniquely locatable
  allowing hyperlinking giving us the
  Web
• Triple - allows information to be communicated in
  a standard way giving us the Semantic
  Web

Aaron Swartz
98
Semantic Web - Why is it useful?

• For documents everything is simple and smooth,
  but for data we are still pre-Web
• The Web requires a human driver to determine
  which links might be relevant to follow and to
  understand the content of each page
• The Semantic Web structures information so
  computers can understand it
• Then they can make useful connections, eg.
  finding a free slot with the nearest dentist and
  booking you in (plus updating your diary)

99
Semantic Web - Why is it useful?

• From this...

Resource
Resource
linksTo
linksTo
Resource
linksTo
linksTo
linksTo
Resource
Resource
Resource
linksTo
Resource
100
Semantic Web - Why is it useful?

• To this...

Image
Document
isBasedOn
isPartOf
Document
hasAuthor
subject
subject
Person
Topic
Topic
livesAt
Place
101
Encoding in RDF
102
RDF - What is it?

• Resource Description Framework
• Formal grammar for the Semantic Web
• Currently the only serialisation/syntax available
  is RDF/XML

103
RDF - How do I use it?

• Describe resources by making statements
• Statements consist of three parts, a "triple",
  eg.
• "X has a Y which is Z"
• "Z is a Y of X"
• Subject - the resource
• Predicate - the property name
• Object - the property's value

104
RDF - How do I use it?

• Each part identified using a URI so it is
  unambiguous (allows matching and validation)
• Subject http//www.example.org/index.html
• Predicate http//purl.org/dc/elements/1.1/crea
  tor
• Object John Smith

egindex.html
John Smith
dccreator
105
Roadmap a side road RDF Triples
Property Name
Value
Property Name
Property Name
Value
Property Name
Value
106
RDF - How do I use it?

• Matching statements on URIs allows applications
  to make connections (navigate the Semantic Web)
• egindex.html dccreator
  staffjohnstaffjohn vcardn
  "John Smithstaffjohn vcardemail
  "john_at_example.com"

egindex.html
staffjohn
dccreator
107
Encoding in RDF/XML - How do I do it?

• egindex.html dctitle "Home
  Page"
• egindex.html dccreator "John Smith"
• ltrdfRDF xmlnsrdf"http//www.w3c.org/1999/0
  2/ 22-rdf-syntax-ns"
• xmlnseg"http//example.com/"
• xmlnsdc"http//purl.org/dc/elements/1.1
  /"gt
• ltrdfDescription rdfabout"egindex.html"gt
• ltdctitlegtHome Pagelt/dccreatorgt
• ltdccreatorgtJohn Smithlt/dccreatorgt
• lt/rdfDescriptiongt
• lt/rdfRDFgt

108
Roadmap triples in a syntax
Syntax - RDF/XML
Property Name
Value
Property Name
Property Name
Value
Property Name
Value
109
Encoding in RDF/XML - How do I do it?

• RDF Schema
• A language for defining RDF semantics
• XML Schemas define XML documents, RDF Schemas
  define RDF models
• Similar to defining an Application Profile
• Allows defining of properties and also classes
  (to group resources together) plus data-typing
  (range and domain)

110
Encoding in RDF/XML - How do I do it?

• RDF Schema example
• Creator is a property
• Creator has a label whose value is Author
• ltrdfRDF xmlnsrdf"http//www.w3c.org/1999/02/
  
  22-rdf-syntax-ns"
• xmlnsrdfs"http//www.w3c.org/2000/01/rd
  f-schema"
• xmlnsdc"http//purl.org/dc/elements/1.1
  /"gt
• ltrdfProperty rdfabout"dccreator"gt
• ltrdfslabelgtAuthorlt/rdfslabelgt
• lt/rdfPropertygt
• lt/rdfRDFgt

111
RDF - Resources

• W3C Semantic Web homehttp//www.w3.org/2001/sw/
• W3C RDF homehttp//www.w3.org/RDF/
• W3C RDF online validator servicehttp//www.w3.org
  /RDF/Validator/

112
Comparing the encoding syntaxes
This is why DCMI recommends RDF/XML
113
Summary
114
Dublin Core Roadmap
DCMI community
Syntax - HTML/XML/RDF
DCMES
Description
Element Name
Element Value
Refinement
Scheme
Lang
Resource
Name
Value
Refinement
Scheme
Lang
Other Elements
Name
Value
Refinement
Scheme
Lang
Registry
Application Profile
XML Schema
RDF Schema
115
Questions
DC-ANZDublin Core Australia New Zealand
supporthttp//www.dc-anz.org/
116
A Roadmap for Implementing Dublin Core

• Douglas Campbell
• National Library of New Zealand Te Puna
  Matauranga o Aotearoa
• THE END