Introduction to Dublin Core

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Introduction to Dublin Core
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Background

• An attempt to improve resource discovery on the
  Web
• Demand for resource discovery
• Demand for resource description
• Demand for resource evaluation
• Now adopted by many resource description
  communities
• Museums, libraries, government agencies, and
  commercial organizations

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Primary Goal of Dublin Core

• Building an interdisciplinary consensus about a
  core element set for resource discovery
• Simplicity of creation and maintenance
• Semantic Interoperability
• International Consensus
• Flexible extensibility
• Metadata modularity on the Web

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Introducing the Dublin Core

• 15 elements of descriptive metadata
• All elements are optional and repeatable
• Dublin Core is extensible
• Offering a starting point for semantically richer
  descriptions

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Dublin Core Element Sets

• Title
• Creator
• Subject
• Description
• Publisher
• Contributor
• Date
• Type

• Format
• Identifier
• Source
• Language
• Relation
• Coverage
• Rights

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Dublin Core and RDF/XML

• Dublin Core is about semantics
• What we are trying to say about resources
• RDF is about structure
• Conventions for encoding the assertions about a
  resource that uses DC semantics
• XML
• Syntax for encoding assertions in RDF
• RDF-encoded DC metadata

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Semantic, Structure, Syntax
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DC in the Real World

• DC originally designed with electronic resources
  in mind
• Physical resources are fundamentally different
• Issues of surrogacy become more important
• Genre, Type, and Format models very greatly
• Difficult to remember what is being described,
  and which characteristics of the resource and its
  surrogates are correct

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Introducing Physical Objects

• Aspects of the real world are key to much to what
  museums do
• Physical objects have dimensions
• 23 46 cm
• 12 52 18 in
• 18.6 cm3
• Physical objects have a form
• Oil on canvas
• Tadcaster limestone
• Stainless steel

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Introducing Physical Objects

• Physical objects change over time
• Constructed between AD524 and 873
• Repaired in AD1270
• Incorporated into ornamental arch in AD1320
• Physical objects move
• Cast in Beijing
• Used in Shanghai
• Taken to Hong Kong
• On display in Taipei

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Introducing Physical Objects

• Physical objects are associated with people
• Written by William Shakespeare
• Acquired by Lord Elgin
• Decreed by the Emperor Hadrian
• Associated with Prince Charles Edward Stuart
• Physical objects are contextualized
• Fired at the Battle of Trafalgar
• Carried on Apollo 11 from the moon
• Printed on the first printing press
• Salvaged from the Titanic

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Introducing Collections

• Museum objects, whether original or surrogate,
  are normally part of a collection
• Collections may be real
• the Sutton Hoo hoard
• the Chinese Warriors
• an aspect of the process by which objects enter
  the museum
• the Burrell Collection
• Solomon Guggengeims art collection
• or simply practical
• Coins at the British Museum
• the Tate Gallerys collection of works by Da Vinci

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Introducing Surrogacy

• Many of the resources we describe are surrogates
  for something else
• a Photograph of King Tutankhamens death mask
• a Photograph of a statue of George Washington
• a film of President Kennedys assassination
• a sound recording of Neil Armstrongs One small
  step for man speech on the moon
• a copy of the Mona Lisa
• a model of the Great Wall of China
• a reproduction of the Chinese Warriors

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Issues of Surrogacy

• Many of the resources we describe are surrogates
  for something else
• We need to be clear whether we are describing the
  resource or its surrogate
• the sculptor of a statue is often not who person
  who made its photographic surrogate
• the model of the Great Wall of China is unlikely
  to have been created at the same date as the
  Great Wall of China itself
• the format of a computer image of the Mona Lisa
  (image/jpeg ?) is not the same as the format of
  the original painting (oil on canvas)

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11 Principle

• A discrete resource should have a discrete
  metadata record
• Resolve issues over original versus surrogate and
  item versus collection
• Associated resources should be linked together by
  means of the Relation element in DC

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11 Principle (Cont.)

• In a record describing a photo of MOULIN DE LA
  GALETTE on a web page
• Renoir is not the creator of the image
• The image was not created during the 19 century
• but you might include these as Subject terms,
  and you could usefully provided a link to the
  record describing the real painting via DCs
  Relation element

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11 Principle (Cont.)

• Equally, in describing the painting itself
• http//www.cc//moulin.jpg is not the Identifier
  of the painting
• but you might link to this image via Relation,
  just to show people what the painting looks like.

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When should I Use DC

• You have a rich standard, need simpler one
• You want to disclose your data to other
  communities using commonly understood semantics
• You want to provide unified access to databases
  with different underlying schemas
• You need core description semantics and dont
  feel compelled to invent them anew.

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Extending Dublin Core

• Semantic Refinement
• Modular Approach

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Extending DC?

• ltCreatorgt
• Paul
• Paul Inc. ?
• Paul xyz ?
• xyz Paul ?
• ltCreatorgt ltfore namegt
• Paul
• ? Paul Inc.
• ? Paul xyz
• ? xyz Paul

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Extending DC (Semantic Refinement)

• Improve descriptive precision by adding
  sub-structure (element qualifier and value
  qualifier)

Creator
First Name
Affiliation
Surname
Contact Info.
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Extending DC(Modular Approach)

• Modular extensibility
• Additional elements to support local needs
• Complementary packages of metadata

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Creator Coverage Date
Creator Coverage Date
Creator Coverage Date
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Element Qualifier

• Refine or enhance the meaning of DC by adding
  qualifiers to DC elements
• Creator (DC.Creator)
• Surname (DC.Creator.Surname)
• Firstname (DC.Creator.Firstname)
• Date (DC.Date)
• Created (DC.Date.Created)
• LastModified (DC.Date.LastModified)

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Value Qualifier

• Refine or enhance the interpretation of the value
• Date1994-05-02 (SchemeISO8601)
• Languagees (Schemerfc1766
• SubjectMyocardial Infraction Pericardial
  Effusion (SchemeMeSH)