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CSA3080Adaptive Hypertext Systems I
Lecture 4Aims, Objectives, and Assumptions of
IR, Hypertext, and UM

• Dr. Christopher Staff
• Department of Computer Science AI
• University of Malta

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Aims and Objectives

• Adaptive Hypertext Systems need Hypertext, User
  Modelling, and Domain Modelling, and a mechanism
  for comparing the user model and the domain model
• General purpose AHSs tend to use IR techniques to
  represent the domain
• ITSs frequently use deeper semantic
  representations, eg, conceptual graphs

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Aims and Objectives

• We informally introduce IR and hypertext, to
  compare their objectives, assumptions,
  similarities and differences
• Well also talk about UM, and its relationship
  with IR and hypertext

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Objectives of IR

• To represent documents in a collection
• To facilitate document retrieval from the
  collection
• User query represents information need
• Matching algorithm compares user query to
  document representations
• Matching documents presented as relevant
• Results may be ranked in order of relevance

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Spectrum of Indexing Methods
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Objectives of Hypertext

• A (not so new) reading system
• Represents an information space (typically as a
  graph)
• Related information can be linked
• Users navigate through hyperspace by traversing
  links
• To enable users to choose which path to follow

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Assumptions of IR

• The user can describe the information need
• The information need can be (sufficiently)
  described using keywords/terms
• A document matching the query will be suitable
  for the particular user (expert v novice)
• A single document contains the information

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Assumptions of Hypertext

• The user can find a relevant document by
  following links
• Links will connect related information
• Related information is linked!

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IR/Hypertext Similarities

• Users can seek information
• IR Query matching
• Hypertext (HT) Browsing
• Collections of documents
• IR Similar documents will have similar
  representations (keywords)?
• HT Similar documents will be linked?

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IR/Hypertext Differences

• User interaction
• HT Follow link - most systems dont directly
  support search
• IR Submit query - Most systems dont directly
  support linking
• Relevant info
• IR relevant info stored in single document
• HT can be spread over multiple, linked documents

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IR/Hypertext Differences

• Organisation
• HT graph (or network), in which related
  documents are linked (at best)
• IR (at best) clusters of similar documents, (at
  worst) no organisation.

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User Modelling

• Represent interesting features of the user
  Brusilovsky96
• Used in many different domains
• Reference
• Kobsa, A. (1993). User Modeling Recent Work,
  Prospects and Hazards, in M. Schneider-Hufschmidt,
  T. Kühme and U. Malinowski, eds. (1993)
  Adaptive User Interfaces Principles and
  Practice. North-Holland, Amsterdam, 1993.
  (http//fit.gmd.de/kobsa/papers/1993-aui-kobsa.pd
  f)

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User Modelling

• Many different ways of representing interests,
  goals, beliefs, preferences
• However the user is modelled, the information
  that he/she can be given is only as good as the
  representation of the domain!

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Conclusion

• Information Retrieval, Hypertext, and User
  Modelling underpin general-purpose Adaptive
  Hypertext Systems
• Weve taken a look at the objectives,
  assumptions, similarities, and differences
  between IR and HT