Adaptive Hypermedia

Hypermedia

“Static” hypermedia Same page content Same links For all users

Problems of hypermedia Users are overwhelmed, too much choice Users get lost “How did I get here” “Where did I find this last time?” Difficult to maintain narrative flow

Visualisation Part of the problem is visualisation –Where am I in the graph? –What do I click on to find my information?

Graph Navigation Hypergraphs

Adaptive hypermedia Works on assumption that not all pages are as relevant for each user at a certain moment in time Tries to adapt the hyperspace to the user Closely related to Personalisation and Recommender Systems (future lectures) –Amazon, etc.

Where is it used? (1) Education On-line information –Electronic encyclopedias –Information kiosks –Virtual museums –E-commerce –Performance support

Typical Situation Museum Tour Guide –Poorly Defined Initial Interests of the visitor –Museum contents not known to the visitor Possible adaptation –Visitor describes initial interests to the guide –Guide points out items of interest that refine the interests of the visitor –Guide in turn refines its guidance through every such experience

Where is it used? (2) Information retrieval –Search-oriented –Browsing-oriented –WebWatcher (CMU) Compares hyperlinks on a page with user model to make recommendations. On-line help/information Lot happening, dedicated conferences

Adapting to what? User Goals / tasks Knowledge; Experience in that hyperspace Background Preferences; Interests => Topic of next week’s lecture on User modeling Environment

What can be adapted? Content = Adaptive presentation Links = Adaptive navigation support

Adaptive Presentation Canned text adaptation –inserting/removing fragments –stretch text –altering fragments –sorting fragments –dimming fragments Natural language generation Modality adaptation

Example of natural language generation

Example application Arts tour Painting Introduction Links to other art demo

Adaptive Navigation Support Link Hiding: disabling, hiding, removal Sorting Annotation Direct guidance Creating new links => Recommender systems lectures

Link Hiding (Example) Introduction to PHP Putting a database on the web Why adaptivity is important Social filtering Content-based filtering

Link Sorting (Example) Why adaptivity is important Content-based filtering Social filtering Introduction to PHP Putting a database on the web

Link Annotation Textual annotation Graphical annotation Font color, type Font size Ready to be learned, Known, Not ready to be learned

Link Annotation (Example) Introduction to PHP Putting a database on the web Why adaptivity is important Social filtering Content-based filtering

Direct guidance (Example) Introduction to PHP Putting a database on the web Why adaptivity is important Social filtering Content-based filtering NEXT

Implementation You need to be change web pages at runtime Depending on what you have figured out about the user (so, need to remember data from one page to the next)

Implementation: General For the ArtTour example I have used PHP PHP = HTML + scripting There are many other ways, servelets, perl, etc But that is not the focus of this course

Implementation: How to do it Take an ordinary HTML file Change its extension to.php Note: for php code to work, it has to be viewed via a web server! Type script code between

Prevent caching Put at start of file <?php // Prevent caching header("Pragma: no-cache"); ?>

If statements if ( ) { }

Session variables Session variables allow the system to remember values from one page to the next Connect to existing session or starts one: session_start(); (put before ) Add new session variables: session_register("SomeName"); Give a session variable a value: $HTTP_SESSION_VARS ["SomeName"] = 0;

Useful use of If statement: <?php if ($HTTP_SESSION_VARS ["BeenHere"]==1) { ?> Welcome back. <?php } ?> <?php $HTTP_SESSION_VARS ["BeenHere"] =1; ?>

How do we adapt? (How?) Adaptive hypermedia - content and navigation What can we adapt to? (To What?) User model 29 Wait, how does this stuff fit together?!

Adaptive hypermedia has grown a lot in the last years... 30