1212 / Department of Computer Science Adaptive Hypermedia 2ID20 Prof. dr. Paul De Bra

1212 / Department of Computer Science Course Topics What is adaptive hypermedia? Reference architecture Example systems and applications Evaluation of adaptive hypermedia The AHA! system Creating adaptive applications using AHA!

1212 / Department of Computer Science 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)

1212 / Department of Computer Science Adaptive Hypermedia Systems

1212 / Department of Computer Science Why 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

1212 / Department of Computer Science Application 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.

1212 / Department of Computer Science Adaptive 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

1212 / Department of Computer Science Adaptive 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 user’s goal(s) in order to adapt (goal can be a topic, a product, an airline trip…) –the system also needs to adapt to the user’s 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 don’t know a close airport to the destination of their trip)

1212 / Department of Computer Science Adaptive 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

1212 / Department of Computer Science Adaptive 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

1212 / Department of Computer Science The 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!

1212 / Department of Computer Science 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

1212 / Department of Computer Science Adaptive Presentation

1212 / Department of Computer Science Adaptive Navigation Support

1212 / Department of Computer Science 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

1212 / Department of Computer Science 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. …

1212 / Department of Computer Science 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)

1212 / Department of Computer Science Adaptive 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

1212 / Department of Computer Science Adaptive 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: hiding+disabling means the link anchor text is just plain text

1212 / Department of Computer Science Example from Interbook 1. Concept role 2. Current concept state 3. Current section state 4. Linked sections state √

1212 / Department of Computer Science 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

1212 / Department of Computer Science What 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

1212 / Department of Computer Science What can we adapt to? (cont.) Background and experience –background = user’s experience outside the application –experience = user’s experience with the application’s 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 user’s environment, like browsing device, window size, network bandwidth, processing power, etc.

1212 / Department of Computer Science Web-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