Constraint

The author declares a set of relations between either instants (=, >, <) or intervals.

Elastic Time Model:

	each multimedia object can also be associated with a minimum, a maximum and an optimal duration, either chosen by the author or automatically fixed by the authoring system depending on the nature of the object (text, image. video, etc.).
	first introduced in TemporalGlue and Firefly.
	For instance, the Company part of our example can be described by the Allen's relations given in Figure 8. The DelayGlob object is a fictive object (without content) which fixes the global duration of the Company part.

The aim of the temporal formatter(Figure 3):

	check the temporal consistency of this set.
	compute one solution.
	Algorithms used for these two phases are issued from either the temporal constraint satisfaction area or linear programming.

Expressive Power:

	Intuitive way of expression.
	Can easily capture the temporal information of multimedia documents.

Autoring Capabilities:

Modifications of the scenario are made easier since the author has not to reconsider the whole structure but only to add or delete a relation.

Challenges:

	systems with good time performances.
	handling local interactions and unpredictable objects.