Last modified May-24-1997
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Jeliot -- Interactive Algorithm Theater
Jeliot is an algorithm visualization environment for animating user algorithms on the World-Wide Web.
It is a product of the research project
at the Department of Computer Science of
the University of Helsinki. Jeliot has been implemented by two groups of CS students. The implementation is based on the ideas
the predecessor of Jeliot. Both the researchers of project and the students contributed to the development of system.
The name Jeliot is a short hand for Java-Eliot, and the name Eliot
becomes from the Finnish word "eliöt" meaning living
With Jeliot the user can produce an animation for an algorithm written in
The user can select which parts of the algorithm are to be included
in the animation. These selections can be changed also during the
Overview of the System
Jeliot is based on the theater metaphor. The code to be animated
is treated as a script of a play. When constructing an
animation, the user acts as the director of the play. For each stage of the
animation he chooses the actors for the roles (data structures) of the
play. More information about the theater metaphor can be found on the
pages describing Eliot.
The architecture of Jeliot is based on the
client/server model. This provides more platform-independence and
reduces the need for specialized software on the client-side. Only
a Java-capable browser is needed. The
writing of the code to be animated, and the actual animation take place
on the client-side, while the analysis of the user's code and the
generation of the animation take place on the server-side.
A normal session with Jeliot proceeds as follows:
These steps are explained in more detail in the inside Jeliot section. More information can also be found in the paper
- The user writes the algorithm he wants to animate, or uses one
of the examples provided on Jeliot Web pages.
- Then he clicks the Start button and the code is sent to the
Jeliot server where it is parsed,
modified, and finally compiled.
- The server sends the URL of the compiled class file back to the
client and the class file is loaded. At the same time the user
can choose the variables to be animated in each of the stages where
the animation takes place.
- The animation starts when the user clicks either the
Run or the Step button in the control panel. The
control panel can also be used to open new stages,
control the speed of the animation, and the original user written
code is shown in that window.
- Each of the stages can be set up differently. For example one of
them might be used to give an overall view of the animation,
while another might concentrate on some detail. The settings can
naturally be altered, even while the algorithm is running.
J. Haajanen, M. Pesonius, E. Sutinen, J. Tarhio, T. Teräsvirta, and P. Vanninen: Animation of user algorithms on the Web. To appear in Proc. VL '97, Visual Langugaes, Capri, Italy.
At this stage Jeliot is still at
a prototype level. At present it is already
too complex to be developed further by students as a part of their studies.
The future of Jeliot is open, but we are seeking funding for its development.
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