Title: Adaptive Hypermedia 2ID20
1Adaptive Hypermedia2ID20
2Course Topics
- What is adaptive hypermedia?
- Reference architecture
- Example systems and applications
- Evaluation of adaptive hypermedia
- The AHA! system
- Creating adaptive applications using AHA!
3What 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)
4Adaptive Hypermedia Systems
5Why Adaptive Hypermedia?
- Problems with (non-adaptive) hypermedia
- authoring hypermedia is difficult because of the
navigational freedom of end-users - using hypermedia is difficult because the author
did not anticipate the path the end-user follows - using hypermedia is also difficult because it is
easy to get lost in hyperspace - Solutions through adaptive hypermedia
- compensate for unexpected comprehension problems
due to the chosen navigation paths - warn users before following links that lead to
problematic navigation paths - offer orientation support using adaptive overviews
6Application Areas
- Educational hypermedia systems
- on-line course text, with on-line multiple-choice
or other machine-interpretable tests - On-line information systems
- information kiosk, documentation systems,
encyclopedias, etc. - On-line help systems
- context-sensitive help, (think of Clippy)
- Information retrieval and filtering
- adaptive recommender systems
- etc.
7Adaptive Educational Hypermedia
- Origin Intelligent Tutoring Systems
- combination of reading material and tests
- adaptive course sequencing, depending on test
results - In Adaptive Educational Hypermedia
- more freedom for the learner guidance instead of
enforced sequence - adaptive content of the course material to solve
comprehension problems when pages or chapters are
read out of sequence - adaptation based on reading as well as tests
8Adaptive On-line Information Systems
- Examples encyclopedia, documentation, but also
shopping sites, airline reservation, etc. - goal provide information about different topics
- users are only interested in a few topics, not in
studying the entire hyperspace - the system needs to know the users goal(s) in
order to adapt (goal can be a topic, a product,
an airline trip) - the system also needs to adapt to the users
knowledge and background, perhaps also location
(e.g. departing city) - users need help most when the concepts they want
do not match the concept structure of the
application (e.g. they dont know a close airport
to the destination of their trip)
9Adaptive On-line Help Systems
- Like on-line information systems, but
- not independent but tied into an application (and
called from that application) - (part of) the context is known through the
application - often this context is the only information about
the user needed to adapt the information - hyperspace is reasonably small
- unfortunately adaptation does not turn bad help
information into good, and it cannot compensate
for missing help information - popular (bad) examples Windows troubleshooter,
Clippy
10Adaptive Information Retrieval/Filtering
- Adaptive Retrieval
- adaptively refine search requests
- adaptively filter out non-relevant search results
- update user model based on implicit or explicit
relevance feedback - context information to be used can be a task,
perhaps from a workflow system - Adaptive Filtering
- filters incoming information without the user
explicitly asking for it - a personalized view interface for the Web can
also be viewed as a filter - relies on relevance feedback to form and update a
user model
11The Future Ambient Intelligence
- Intelligent home (and office or building)
- automatic heating/climate control
- automatic lighting, kitchen,
- automatic communication redirection
- adaptive information services and help
- adaptive technology makes the technology
disappear into the environment - a dream? not for long!
12What 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
13Adaptive Presentation
14Adaptive Navigation Support
15Canned 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
16Example 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.
17Canned 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)
18Adaptive Navigation Support
- Direct guidance
- like an adaptive guided tour
- next button with adaptively determined link
destination - Adaptive link generation
- the system may discover new useful links between
pages and add them - the system may use previous navigation or page
similarity to add links - generating a list of links is typical in
information retrieval and filtering systems
19Adaptive Navigation Support (cont.)
- Adaptive link annotation
- all links are visible, but an annotation
indicates relevance - the link anchor may be changed (e.g. in color) or
additional annotation symbols can be used - Adaptive link hiding
- pure hiding means the link anchor is shown as
normal text (the user cannot see there is a link) - link disabling means the link does not work it
may or may not still be shown as if it were a
link - link removal means the link anchor is removed
(and as a consequence the link cannot be used) - a combination is possible hidingdisabling means
the link anchor text is just plain text
20Example from Interbook
4
3
2
v
1
1. Concept role 2. Current concept state
3. Current section state 4. Linked sections state
21Adaptive 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
22What can we adapt to?
- Knowledge of the user
- initialization using stereotypes (beginner,
intermediate, expert) - represented in an overlay model of the concept
structure of the application - fine grained or coarse grained
- based on browsing and on tests
- Goals, tasks or interest
- mapped onto the applications concept structure
- difficult to determine unless it is preset by the
user or a workflow system - goals may change often and more radically than
knowledge
23What can we adapt to? (cont.)
- Background and experience
- background users experience outside the
application - experience users experience with the
applications hyperspace - Preferences
- any explicitly entered aspect of the user that
can be used for adaptation - examples media preferences, cognitive style,
etc. - Context / environment
- aspects of the users environment, like browsing
device, window size, network bandwidth,
processing power, etc.
24Web-based Adaptive Hypermedia
- Client-server architecture using HTTP
- only page accesses are registered (not scrolling,
within-page scripting code or animations, etc.) - following a link activates a server-side program
(CGI-script, Java Servlet, ) - the program uses the link URL and the user model
to determine which page to return - the program performs content and link adaptation
based on the user model (and some adaptation
rules) - the program updates the user model taking into
account that the user will read the presented
information