Abstract: In this paper, we examine some problems that authors face in creating adaptive hypertext, and why systems may need to provide more than one mechanism to authors. We discuss two such mechanisms as they have been implemented in ReCourse, a course management system, http://www.webrecourse.com.
Keywords: adaptive hypertext, dynamic hypertext, authoring, web-based course management systems
ReCourse allows an author to write a single document which can dynamically choose its content when a reader selects a particular topic.
We call this Retargeting, because the information is retargeted to different readers and different audiences. Such retargeting is a staple among course instructors who teach similar courses to different audiences, or teach the same course multiple times under different circumstances.
In this paper, we presume that the instructor/author knows the criteria which have segmented the readers, so that readers need only register for the correct group and the pages will be chosen dynamically for them. This is currently done statically, but future versions of ReCourse will address the (difficult) issue of discovering the appropriate information about the reader. However this is done, the author still has to decide what information is appropriate for what collection of reader attributes.
We consider retargeting one of the integral features of adaptive hypertext from the author's perspective.
Although we had preliminary versions of the tools for web page creation and retargeting implemented, we didn't make them available because we wanted to see how authors actually created the pages they used within ReCourse, and to test out some hypotheses we had developed.
We had hypothesized that some instructors would wish to author their own pages using HTML (and other languages such as java, cgi etc.), but that less computer-literate instructors would require a point and click tool. These two groups did exist. (There was a third group that used the campus's page creation service, but even they professed a wish to be able to retarget the material once it was created for them.)
Authoring for the HTML-group
We designed special HTML-like tags for this group. When authoring documents for use within ReCourse, writers can use special tags such as <omit> </omit>, <precondition name >, <postcondition name >
The <omit> </omit> tags are inserted into documents when the text between them is not to be shown when a user matches a particular profile. The <precondition name >, <postcondition name > tags force inclusion of particular material - when the precondition name matches a postcondition name, both pieces of information must be included. We are currently investigating other tags.
Authoring for the HTML-group
A tool currently called Site Composer allows both pages creation and retargeting. Page creation is accomplished by selecting graphics, dragging them to the desired position in the page, writing and placing text, links and other hypermedia objects. Retargeting is accomplished by selecting various objects on the page and then saving them to a group name.
Adaptive hypertext is desirable in web applications to allow readers to see what is appropriate for them. But such features require a set of tools "adaptive" to the various needs of authors.