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Interactive problem solving support
Instead of waiting for the final solution, this technology can provide a student with intelligent
help on each step of problem solving. The level of help can vary: from signaling about a wrong
step, to giving a hint, to executing the next step for the student. The systems which implement
this technology (often referred to as
understand them, and use this understanding to provide help and to update the student model.
The classic example is the LISP-TUTOR [2]. This technology is also represented by a number
of Web-based AIES (Tables 1 and 3).
is a more recent and a move powerful technology.interactive tutors) can watch the actions of the student,The example-based problem solving
helping students to solve new problems not by articulating their errors, but by suggesting them
relevant successful problem solving cases from their earlier experience (it could be examples
explained to them or problems solved by them earlier). An example is ELM-PE [51]. In the Web
context, this technology is implemented in ELM-ART [12] and ELM-ART-II [53].
In the area of traditional ITS, the interactive problem solving support technology absolutely
dominates. Interactive problem solving support is an ultimate goal of almost any ITS, while
intelligent analysis of student solutions is often considered imperfect (and example based
problem solving support is too rare to consider as a competitor). Again, the Web context changes
the situation. Both intelligent analysis of student solutions and example based problem solving
support appears to be very natural and useful in Web context. Both technologies are passive
(works by student request) and can be relatively easy implemented on the Web using a CGI
interface. Moreover, an old standalone AIES, which uses these technologies, could be relatively
easy ported to the Web by implementing a CGI gateway to the old standalone program. It is not
surprising that these technologies were among the first implemented on the Web. An important
benefit of these two technologies in the Web context is their low interactivity: both usually
require only one interaction between browser and server for a problem solving cycle. This is very
important for the case of slow Internet connection. These technologies can provide intelligent
support when a more interactive technology will be hardly useful. Currently, these technology
dominates in Web context over more powerful and interaction hungry interactive problem
solving support.
Interactive problem solving support technology is the last ITS technology migrated to the
Web. The problem here is that the "fast-track" approach of implementing Web-based ITS
(developing a CGI interface to an older standalone ITS) used in pioneer systems does not work
properly for this technology. It could be well illustrated by the PAT-Online system [41], which
was probably the first trial to implement interactive problem solving support on the Web. This
system uses a form-based CGI-AppleScript interface to a standalone Practical Algebra Tutor
(PAT) system. Since CGI interface is passive, the Web version of the system had to provide a
"submit" button for the student to get the feedback from the system. Naturally, it also added
another feature, which was essential for students with a slow Internet connection: a possibility to
request a feedback once after performing several problem solving steps. As a result, PAT-Online
moved to the category of an intelligent problem analyzers, more exactly, to a subcategory of
analyzers that are capable to analyze incomplete solutions (ELM-ART also belongs to this
subcategory). The intelligent analyzers of this subcategory can be placed between traditional
analyzers and interactive tutors (in Tables 1 and 3 they are marked with keyword "partial",
however, they can't be considered as real interactive tutors).
A real interactive tutor is expected to be not only interactive, but also active. It should not
sleep from one help request to another, but instead should be able to monitor what the student is
doing and instantly react to errors. It simply can't be implemented with the traditional server-side
CGI interactivity and requires client-side interactivity based on Java. Java technology has
matured very recently. Two years ago the review [8] named it as a prospective platform for Webbased
AIES and mentioned only three Java-based systems. Now Java provides a reliable solution
for Web-based interactive tutors. To be more exact, Java offers two different solutions. One
solution is a tutor implemented completely in Java. It could be a Java applet working in a
browser, or a Java application. Another solution is a distributed client-server tutor where a part of
technology is the newest one. This technology is
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