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Last update: 2005-05-20

End: 2003-01

AHA! progress report February 25, 2002

transparent adaptive functionality for web servers


The NLnet AHA project has started on July 1, 2001. The current team consists of the following people:

  • Natasha Stash is employed full-time by the AHA project for the duration of the project (one or two years depending on funding).
  • David Smits is a part-time intern at TU/e from September 1, 2001 to February 28, 2002. From March 1, 2002 he will be a part-time junior researcher working on AHA.
  • Davy Floes is a thesis student at UIA from October 1, 2001 to June 30, 2002.
  • Koen Verheyen is a thesis student at UIA from October 1, 2001 to June 30, 2002. He is continuing the work of a previous student from TU/e (Jurgen van Westreenen).

In addition, supervision is provided by prof. dr. Paul De Bra, and when needed also by dr. Ad Aerts, dr. Lora Aroyo, dr. Licia Calvi, dr. ir. Alexandra Cristea and dr. ir. Geert-Jan Houben.

Progress (since previous report) up to this date

The status of the AHA project as of February 25, 2002 is described below. It lists the items that have been realized or worked on since the previous progress report.

  • AHA as previously ported to the Apache/Tomcat server version 3. (The current production version only works with Sun's JSWDK, a minimal server built on top of the Servlet runner.) The port is currently being updated for Tomcat version 4. This port is done by Paul De Bra. The upcoming production release of AHA will most likely use Tomcat version 4.
  • A new data structure for concepts, with their requirements and with condition-action rules for user model updating has been designed (by David Smits, Davy Floes and Koen verheyen). An XML DTD for the external representation of this structure has been designed, that will be used in the upcoming release.
  • A new core engine for AHA has been developed by David Smits. It works with the new data structure in which concepts have multiple attributes and condition-action rules. The upcoming release will feature the new core engine.
  • In preparation of wider acceptance for AHA Natasha Stash has been investigating the use of modularized XML DTDs. The aim is to use pages that use a combined AHA and XHTML DTD. The result will be that plain XHTML pages can be augmented with AHA constructs (or not) and used with AHA this way. This makes it easier to include external documents. The results of this investigation are mixed:
    • Modularized DTDs work with the most recent Xerces parser (included with Tomcat), so a combination of AHA with XHTML or SMIL is possible.
    • Because the DTDs to be parsed are large, performance is not yet acceptable. It appears that the previous "trick" to hide all XML tags except for AHA tags will still be needed to achieve acceptable performance.


Because of technical difficulties (broken computer) some work was shifted. (This has lead to the investigation of modularized DTDs instead of working on an intermediate release of AHA.) As a result, the planned release of AHA will be postponed until around April 1, 2002. The parts currently being worked on in the AHA project, and the new corresponding milestones, are as follows:

  • The next AHA is planned for around April 1, 2002. It will include the following parts/features:
    • Apache/Tomcat as well as JSWDK support. Complete installation instructions for both servers and for Linux as well as Windows 2000.
    • New core engine with condition-action rules.
    • New XML format for concepts/requirements/generate rules.
    • Choice between file (XML) or database (mySQL).
  • A combined editor for generate and requirement rules will be built, extending the requirement editor (completed by Jurgen van Westreenen on November 30, 2001). This task will be performed by Koen Verheyen (at UIA). The exact syntax for the rules has been determined (and illustrated with an example). The editor will be completed by May 31, 2002. It will be based on Java Applets.
  • The current modules for multiple-choice tests, user-model updates and preferences, will be integrated and extended to form a general-purpose forms interface. This task will be performed by Davy Floes (at UIA). The forms element types for user model elements have been defined, as well as the corresponding authoring tools. The editor and engine support will be completed by May 31, 2002. It will be based on Java Applets.
  • Natasha Stash will continue the investigation to use XML-based page formats like XHTML, extended with AHA tags. When a combined format can be defined and used the need for a separate document editor for AHA will be eliminated, provided that general-purpose XML editors become available. This XML support will be incorporated in the release scheduled for July 1, 2002.
  • The period of June 1, 2002 to June 30, 2002 will be used to integrate the tools and the documentation. A new AHA release will be published on July 1, 2002.
  • AHA is being used already in some places, with or without our knowledge. We will be working towards providing AHA releases (on April 1 and July 1) to:
    • Alessandra Cini from the Universidade Federal do Rio Grande do Sul
    • Wendy Hall from the University of Southampton

Project Year 2

Initial plans for developments on AHA in the second project year include:

  • The rules that are possible with the new rule editors and engine can exhibit undesirable behavior (problems with termination and confluence). Natasha Stash will investigate the problem of predicting and detecting these situations. This will result in a verification module to be incorporated into the rule editor. Theoretical preparatory work has been done by Hongjing Wu. Apart from pure implementation this part of the project will also involve research into eliminating "false alarms", i.e. warnings about potential infinite loops which in fact cannot be infinite loops.
  • Many constructs for adaptation and for user model updates are independent of the concept. For instance, updates to knowledge or interest value will be the same for many pages; the rules that implement prerequisites will be the same for all prerequisites, etc. Two new tool-parts will be built:
    • an authoring interface for defining templates and the translation of templates to the underlying basic rule language;
    • an extension of the generate/requirement editor to allow the use of templates.
  • In the current AHA system pages are composed of fragments, conditionally included in the presentation, in the order they appear in the page. The evaluation of the requirements will be generalized to a numeric value. This value can then be used to perform sorting of fragments, thus making it possible to create personalized information retrieval tools, and to allow the generation of personalized guided tours.

Developments of the AHA project can be followed on the AHA website, at the address

Publication / Dissemination

The AHA project, and the prototype system will be submitted for demonstration to (at least) the following international conferences:

  • WWW2002, The Eleventh International World Wide Web Conference, Honolulu, USA, May 7-11, 2002.
  • SANE2002, Maastricht, May 27-31, 2002.
  • AH2002, The Second International Conference on Adaptive Hypermedia and Adaptive Web-Based Systems, Malaga, Spain, May 29-31, 2002.
  • HT2002, ACM Conference on Hypertext and Hypermedia, College Park, Maryland, USA, June 11-15, 2002.
  • E-Learn, Montreal, October 15-19, 2002.

There have been initial contacts with potential users of AHA. At least the release scheduled for April 1, 2002 (but also the July 1 release) is needed to really attract users because of the need to demonstrate the full functionality of the AHA system.

AHA is currently being used by:

  • Alessandra Cini from the Universidade Federal do Rio Grande do Sul

AHA is also scheduled for study and/use by the following people:

  • Wendy Hall from the University of Southampton has volunteered a PhD student who will investigate AHA as part of his/her research on adaptive hypermedia;
  • Petra Heck at ordina is working on knowledge portals and is willing to investigate the use of AHA for personalization; (she is currently a masters student but plans to stay at Ordina after graduating);
  • Antoinette van der Voort from "external communication" of TU/e has presented plans for a personalized portal for her website; AHA (when available) can be used to avoid duplication of information in the "information for" and "information about" entries of the website.

More potential users of AHA will be contacted during the upcoming demos at conferences.

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