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indispensable to use a language which covers extensions of XML, specify temporal
and spatial synchronization of multimedia information, call other presentation
languages, and make users interact with presentation.
To control synchronization and interaction of multimedia information, we emply
a knowledge representation language, QUIK
Liu et al 99)
, as a control language of multi-
media information. The language is an ancestor of
Yokota et al 99)
, a DOOD
language of the Japanese FGCS project. The reasons why we employ the language
are following:
•
As it is a powerful knowledge representation language, it is easy to represent
semantical extensions of XML.
•
The language supports representation and synchronization of multimedia
information and it is easy to call other languages.
•
As the language is also a programming language, it supports debugging
functions: that is, it is possible to support interactive multimedia presentation
functions such as stop, backward, forward, and change of temporal and
spatial layouts of multimedia objects.
An XML document is processed as follows:
1.
An XML document is pre-edited: that is, multimedia information is inserted
into the document if necessary.
2.
An XML document is converted into a QUIK program.
3.
The QUIK interpreter executes a document in QUIK and presents
multimedia information to a user.
4.
A user can interrupt (stop) the execution at any time, see a synchronization
graph, modify temporal and spatial layouts of multimedia objects, and re-
start from arbitrary point.
5.
A modified program can be strored as an XML document, is necessary, as
a new version.
It is unnecessary for users to know a QUIK program. As for kinds of multimedia
objects and synchronization mechanism, please refer
Fujino et al 00)
.
6
Conclusions
We can see many enhancement requests of XML from viewpoints of many
applications. In this article, we describe an extended model of XML from our
applications' requirement point of view and their interactive presentation
mechanism. XML is not syntactically extended, but semantically extended by
introducing special attributes. The reason why we take this approach is that we
