Modelling web resources

1
Modelling web resources

• Ketil Albertsen, Paradigma project
• National Library of Norway

2
Aggregates

• Documents (in a bibliographic sense) spread over
  multiple web pages
• Web pages consisting of multiple visual/sound
  components, or traditional multipart documents
• Web pages requiring a style sheet, font file etc.
  for presentation (not directly visible to user)
• Snapshots of a web page varying with time, the
  web version of integrating resources.

3
Aggregates

• Web documents available in multiple formats
  HTML, PDF, DOC,
• Web pages providing information in alternative
  languages or adapted to several web browsers
• Blogs and similar pages, the web version of
  incrementally issued continuing resources
• Expressions based on multiple creative efforts A
  song (melody text), rewritings,

4
ClaimImplicit aggregates, based on objects
having some common attribute value, are not
sufficient

• Inspecting candidate objects for common attribute
  values is costly, even when using indexes.
• Access to attributes may require document
  interpretation, requiring knowledge of the
  format.
• An aggregate may span only a subset of objects
  having a given attribute value.
• Many aggregates are not based on stored, common
  object attributes.
• Aggregates frequently need an ID and possibly a
  bibliographic description.

5
Solution Aggregate objects, boxes

• General container objects holding (references to)
  other objects.
• Boxes can be identified and described as
  composite objects.
• The model defines classes of boxes, each class
  identifying a set of structural properties.
• The application/user may identify multiple
  applications of each box class.

6
Box classes(suggested)

• Component Ordered, all components presented
• Variant Unordered, one of several.
• Synchronous Parallel presentation in real time.
• Update Later components replace earlier ones,
  integrating CR
• Extension Later components are added to earlier
  ones, successively issued CR.
• Based On One component is a further development
  of one or more other components.
• Fragment Of One component is part of another
  one.

7
Box class properties

• Cardinality, i.e. 1n, mn, 11
• Existence, i.e. will removal of one component
  imply removal of another
• Dependency, e.g. a component depends on a whole
• Recursion, e.g. a chapter may contain subchapters
• Ordering, usually in time or space
• Reference, does a dependent component have an
  independent value or is it integrated with the
  other object?

8
Other Paradigma extensions

• Agent objects, for modeling real world objects
  that cannot themselves be digitized.
• Point/fragment reference objects(further
  discussed tomorrow)