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1 of [email protected] University of Malta
CSA3080: Lecture 12© 2003- Chris Staff
CSA3080:Adaptive Hypertext Systems I
Dr. Christopher StaffDepartment of Computer Science & AI
University of Malta
Lecture 12:Adaptation Techniques I
2 of [email protected] University of Malta
CSA3080: Lecture 12© 2003- Chris Staff
Aims and Objectives
• We will look at stages in the adaptation process and revisit the problems that AHS try to solve (this lecture)
• We will look at two example AHSs: Personal WebWatcher and MetaDoc, and some of the research that’s happening at UoM (next lecture)
3 of [email protected] University of Malta
CSA3080: Lecture 12© 2003- Chris Staff
Stages in the Adaptation Process
• Collect data about the user
• Process data to build/update user model
• Apply user model to provide the adaptation– Last stage always fully automated in adaptive
hypertext systems– 1st and 2nd stages may require user intervention.
Ideally, fully automated
4 of [email protected] University of Malta
CSA3080: Lecture 12© 2003- Chris Staff
Stages in the adaptation process
• If user and system need to co-operate to achieve adaptivity, then it is called collaborative user modelling
Application"Administrator"
UserSystem
Data about user
User Model
Adaptation Effect
Processes
ProcessesCollects
Provides
Edits
Provides
Edits
Provides
From [Brusilovsky96]
5 of [email protected] University of Malta
CSA3080: Lecture 12© 2003- Chris Staff
Problems Revisited
• Lost in HyperSpace
• Cognitive overload
• Complexity of the search space
• Search-browsing
• Static hypertext structure
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CSA3080: Lecture 12© 2003- Chris Staff
Generic solutions
• Adaptive Presentation
• Adaptive Navigation
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CSA3080: Lecture 12© 2003- Chris Staff
Lost in HyperSpace
• Mark-up nodes to include link to landmark which user knows about
• Show relationship between landmark node and current node
• Reduce cognitive load on user
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CSA3080: Lecture 12© 2003- Chris Staff
Cognitive overload
• Move (some) linking functions into AHS system by, e.g., providing "See Also" links
• Automatic/dynamic linking
• Reduce number of outlinks by removing links to non-relevant nodes
• Link recommendation services
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CSA3080: Lecture 12© 2003- Chris Staff
Complexity of the search space
• Removing links reduces the size of the search space
• Recommending links assists the user in deciding which links are likely to lead to relevant information
• Automatically modifying content enables readers to understand concepts at their level of understanding
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CSA3080: Lecture 12© 2003- Chris Staff
Complexity of the search space
• Learn from user access paths to re-organise hyperspace
• Learn to associate user terminology with document content
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CSA3080: Lecture 12© 2003- Chris Staff
Search-browsing
• Dynamic linking as a result of where user action is combined with any stated query terms
• Recommend links (paths) to relevant documents
12 of [email protected] University of Malta
CSA3080: Lecture 12© 2003- Chris Staff
Static hypertext structure
• Users can modify structure, and/or system can learn from users
• What change(s) to hypertext systems would be required? IR systems?
• Dynamic hypertext systems
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CSA3080: Lecture 12© 2003- Chris Staff
What can be adapted?
• A hypertext is a collection of nodes that are connected by links
• So what can be adapted?– The node content and user interface - adaptive
presentation– The node organisation and hyperspace
representations (e.g., index, map, overview) - adaptive navigation
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CSA3080: Lecture 12© 2003- Chris Staff
Adaptation Technologies
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CSA3080: Lecture 12© 2003- Chris Staff
Adaptive Presentation
• Anything to do with adapting how the presented material is displayed to users
• Examples– Adapting the UI (more to do with adaptive user
interfaces than adaptive hypertext per se)– Modify data presentation so that it is presented in
user's preferred choice (e.g., charts)
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CSA3080: Lecture 12© 2003- Chris Staff
Adaptive Presentation
• More examples– Automatically expand/collapse glossary items
according to user's level of expertise– Provide "trails" through hyperspace according to
user's level of expertise– Can be fairly complex - if user does not know
concept A, then unlikely to know concept B, so concept B should also be automatically expanded
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CSA3080: Lecture 12© 2003- Chris Staff
Adaptive Presentation
• Adaptive presentation can be useful in any adaptive hypertext system, but mostly used in Intelligent Tutoring Systems
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CSA3080: Lecture 12© 2003- Chris Staff
Adaptive Navigation
• Focused around implicit link types in Web-based systems (ideally, link types are explicit)
• Identify as many implicit link types as possible…
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CSA3080: Lecture 12© 2003- Chris Staff
Direct Guidance
• Mainly through "Next" buttons!
• Can include link/path recommendation
• What are the pre-requisites?
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CSA3080: Lecture 12© 2003- Chris Staff
Adaptive Sorting of Links
• Ordering links according to some ranking scheme
• On what basis?
• On which of the implicit link types can this be provided?
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CSA3080: Lecture 12© 2003- Chris Staff
Adaptive hiding of links
• Hide links which would lead to non-relevant information
• What are the pre-requisites? In ITS systems? In generic AHSs?
• Identify implicit link types which support adaptive hiding
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CSA3080: Lecture 12© 2003- Chris Staff
Adaptive annotation of links
• Mark-up anchor text/link description to explain the information at the destination of the link
• Description must be adaptive!