CSA3212: User-Adaptive Systems

1. CSA3212: User-Adaptive Systems Topic 6: Adaptation Techniques Dr. Christopher Staff Department of Intelligent Computer Systems University of Malta

2. Aims and Objectives • We will look at stages in the adaptation process and revisit the problems that AHS/UAS try to solve

3. 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. Stages in the adaptation process • If user and system need to co-operate to achieve adaptivity, then it is called collaborative user modelling From [Brusilovsky96]

5. 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

6. Generic approaches • Adaptive Presentation • Adaptive Navigation

7. 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)

8. 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

9. Adaptive Presentation • Adaptive presentation can be useful in any adaptive hypertext system, but mostly used in Intelligent Tutoring Systems • e.g., MetaDoc

10. Adaptive Navigation • Focused around implicit link types in Web-based systems (ideally, link types are explicit) • E.g., Letizia, WebWatcher, Personal WebWatcher, HyperContext • Already identified implicit link types in previous lecture…

11. Problems Revisited • Lost in HyperSpace • Cognitive overload • Complexity of the search space • Search-browsing • Static hypertext structure

12. 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

13. 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 • Add explanations/remove extraneous text

14. 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

15. Complexity of the search space • Learn from user access paths to re-organise hyperspace • Learn to associate user terminology with document content

16. Search-browsing • Dynamic linking as a result of where user is combined with any stated query terms • Recommend links (paths) to relevant documents

17. 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

18. Adaptation Technologies

19. Direct Guidance • Mainly through "Next" buttons! • Can include link/path recommendation • What are the pre-requisites?

20. 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?

21. 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

22. Adaptive Annotation of Links • Mark-up anchor text/link description to explain the information at the destination of the link • Description must be adaptive!

23. Adaptive Link Generation • Must links be predetermined? • Can automatically discover new links and add them permanently • Must the destination of links be fixed? • Add similarity-based links or recommended links (temporary) • E.g., adapt navigational links to point to landmarks known to user

24. Insert/remove Text Fragments • Automatically add or remove text fragments based on predetermined information about user’s knowledge of topics

25. Stretchtext • Expand or contract text based on system’s knowledge of what user already knows • Similar to insert/remove text, but different technology • User can also interactively expand/contract text to give feedback to system

26. Dimming Fragments • Rather than modifying the presentation of a familiar page (and confusing the user’s mental model of the page), dim rather than hide non-relevant information

27. Adaptation of Modality • How should information be presented to user? • Speech, music, animation, video, text? • Assumes that information exist in different forms to begin with!