Adaptive Hypermedia

1
Adaptive Hypermedia

• Dr. Alexandra Cristea
• a.i.cristea_at_tue.nl
• http//wwwis.win.tue.nl/alex/

USI intensive course Adaptive Systems February
2005
2
Adaptive System course parts

• Adaptive Systems, Generalities
• User Modeling
• Data representation for AS
• Data manipulations for AS
• Adaptive Hypermedia as AS
• LAOS for AH
• LAG for AH
• MOT for AH
• Other types of Adaptive Systems
• Conclusions

3
Outline

• Adaptive Hypermedia
• Authoring for Adaptive Hypermedia
• AH Authoring reference architecture LAOS
• A closer look on adaptation design LAG
• Learning Styles in Adaptive Hypermedia
• Authoring system MOT
• Delivery System AHA!
• Conclusions

4
1. Adaptive Hypermedia of the Past, Present and
Future

• Definitions
• Why AH?
• Application areas
• What to adapt?
• Adapt to what?
• New solutions

5
1. Adaptive Hypermedia

• Definitions
• Why AH?
• Application areas
• What to adapt?
• Adapt to what?
• How to adapt - past?
• Obstacles AH
• New solutions

6
(No Transcript)
7
What is Adaptive Hypermedia?

• Hypermedia
• different media types used in a single
  application (text, images, sound, video, )
• non-linear structure with navigation through
  hyper-links
• Adaptive
• application forms a model of the context in which
  it is used (user, place, time, device, etc.)
• application adapts to that context (can show
  different information, different media, different
  links, etc.)
• adaptation and user modeling interact with each
  other (or else we say the application is
  adaptable, not adaptive)

8
Index

• Definitions
• Why AH?
• Application areas
• What to adapt?
• Adapt to what?
• How to adapt - past?
• Obstacles AH
• New solutions

9
The need for personalization
10
Why AH?

• Problems with hypermedia applications
• navigational freedom which links are relevant
  (for this user) ?
• comprehension what has the user seen before when
  reaching a certain node?
• presentation what fits the users screen? how
  much network bandwidth and processing power is
  available?

11
Why AH?

• Opportunities with adaptive hypermedia
• guide users towards relevant information (users
  can reach relevant information more easily and
  more quickly)
• make sure users can understand the presented
  information
• change the presentation so that it fits the
  users platform and environment

12
Index

• Definitions
• Why AH?
• Application areas
• What to adapt?
• Adapt to what?
• How to adapt - past?
• Obstacles AH
• New solutions

13
Application areas AH

• Many application areas
• thus very different systems?
• Educational hypermedia (course texts)
• On-line information systems
• On-line help systems
• Information retrieval hypermedia
• Institutional (or corporate) hypermedia
• Personalized views

14
What Do We Adapt in AH?

• Adaptive presentation
• adapting the information
• adapting the presentation of that information
• selecting the media and media-related factors
  such as image or video quality and size
• Adaptive navigation
• adapting the link anchors that are shown
• adapting the link destinations
• giving overviews for navigation support and for
  orientation support

15
Adaptive Presentation
16
Adaptive Navigation Support
17
Adaptive presentation

• The content of what is seen on the screen can be
  adapted according to current users model status.
  
• e.g., a qualified user can be provided with more
  detailed and deep info while a novice can receive
  additional explanation.

18
Content adaptation types

• Additional (or prerequisite or comparative)
  explanations Under a given set of circumstances
  some additional content is presented.
• Explanation variants Different versions of an
  explanation exist and are selected depending on
  the user.
• Sorting The most relevant information for a user
  is presented first.

19
Canned Text Adaptation

• Inserting/removing fragments
• prerequisite explanations inserted when the user
  appears to need them
• additional explanations additional details or
  examples for some users
• comparative explanations only shown to users who
  can make the comparison
• Altering fragments
• Most useful for selecting among a number of
  alternatives
• Can be done to choose explanations or examples,
  but also to choose a single term
• Sorting fragments
• Can be done to perform relevance ranking for
  instance

20
Example from 2L690

• Before reading about Xanadu the URL page shows
• In Xanadu (a fully distributed hypertext
  system, developed by Ted Nelson at Brown
  University, from 1965 on) there was only one
  protocol, so that part could be missing.
• After reading about Xanadu this becomes
• In Xanadu there was only one protocol, so that
  part could be missing.

21
Canned Text Adaptation (cont.)

• Stretchtext
• Similar to replacement links in the Guide
  hypertext system
• Items can be open or closed system decides
  adaptively which items to open when a page is
  accessed
• Dimming fragments
• Text not intended for this user is de-emphasized
  (grayed out, smaller font, etc.)
• Can be combined with stretchtext to create
  de-emphasized text that conditionally appears, or
  only appears after some event (like clicking on a
  tooltip icon)

22
Adaptive navigation support

• Guidance methods
• Global guidance methods
• Local guidance methods
• Orientation support methods
• Global orientation support
• Local orientation support

23
Link adaptation types

• Direct guidance Next button.
• Restricting access
• Removing, disabling, hiding.
• Sorting and presenting the most relevant or most
  ready to be learned links first.
• Annotation (colour)
• Map adaptation techniques

24
Example from Interbook
4

3
2
v
1
1. Concept role 2. Current concept state
3. Current section state 4. Linked sections state
25
Adaptive Navigation Support (cont.)

• Map adaptation
• complete (site)maps are not feasible for a
  non-trivial hyperspace
• a local or global map can be adapted by
  annotating or removing nodes or larger parts
• a map can also be adapted by moving nodes around
• maps can be graphical or textual
• adaptation can be based on relevance, but also on
  group presence

26
Adaptive vs. adaptable
personalized
adaptive
adaptable
System-tuned
User-tuned
27
Adaptivity vs. adaptability

• An adaptable system provides users with options
  (tuners / handles) of determining some
  alterations to aspect, contents or functionality
  of the system, according to their preferences.
• An adaptive system adapts to the new conditions
  (usually deduced from a user model) automatically.

28
A Comparison between Adaptive and Adaptable
Systems
Gerhard Fischer 1 HFA Lecture, OZCHI2000
29
Index

• Definitions
• Why AH?
• Application areas
• What to adapt?
• Adapt to what?
• How to adapt - past?
• Obstacles AH
• New solutions

30
Adapt to what?

• User ? user model (UM)
• Goals ? ??
• Domain ? domain model (DM)
• Media ? presentation model (PM)

31
First Non-UM
32
Adapt to what?

• Goal local and global
• Goal is the answer to the question Why is the
  user using the hypermedia system and what does
  the user actually want to achieve?
• Goals can be local or global. Local goals may
  changed quite often. For example, the
  problem-solving goal is a local one, which
  changes from one educational problem to another
  several times within a session. Global goal can
  be the users learning goal.

33
Adapt to what?
Domain model properties
Adapt to
34
Adapt to what?

• Context / environment
• aspects of the users environment, like browsing
  device, window size, network bandwidth,
  processing power, etc.

35
Adapt to what?
Adapt to
Users
36
Adapt to what (else)?

• Knowledge about the subject domain (and possibly
  also knowledge about the system)
• Preferences
• Interests
• Learning or cognitive styles
• Background profession, language, prospect,
  capabilities
• Experience
• Navigation history

37
Index

• Definitions
• Why AH?
• Application areas
• What to adapt?
• Adapt to what?
• How to adapt - past?
• Obstacles AH
• New solutions

38
How do AH work?

• Most AHS react to individual user requests
• 1. retrieve the user model
• 2. (if necessary) retrieve the domain model
• 3. retrieve the requested resource(s)
• 4. perform adaptation to the resource
• 5. update the user model
• (maybe 4 and 5 are reversed)

39
Traditional UM

• attribute-value pairs to describe aspects of the
  user, the computing environment, the network,
  etc.
• an overlay model with for each DM concept a set
  of attribute-value pairs to denote how the user
  relates to the concept.

40
AM adaptation rules

• Purpose is to describe how an AHS
• updates the user model
• generates adaptation (presentation
  specifications)
• Description uses condition-action rules
• under which condition is the rule executed
• which (user model) concept attribute is updated
• does this update trigger other rules?

41
The Adaptation Engine

• The core of each AHS is an engine that executes
  the adaptation rules (or equivalent)
• page access triggers one or more rules
• these rules generate user model updates
• the rules trigger other rules that generate
  more updates (does this process end ?)
• the engine generates an adapted page.