TTS-driven Synthetic Behavior Generation Model for Embodied Conversational Agents - Coverbal Synchrony in Human-Machine Interaction - page 351

Figure 10. Transforming HRG structure into procedural animation specifi cation.
gestures are to be animated, as specifi ed by the phase-items. The ' start '
attribute is also important in the context of the TTS-driven behavior
generation. For example, this attribute is an absolute temporal value
that represents how long the animation of the described behavior has to
be withheld prior to execution. It is equivalent to the ' delay ' attribute, as
stored in the Content unit. And, the ' durationDown ' attribute describes
the duration of the transition from the excited to a neutral (or previous)
state. It is equivalent to the ' duration-down' attribute also stored in the
Content units.
Further, each PI unit in the HRG structure represents a sequence
of body-parts moving in a parallel manner. Such a sequence has to
be represented in the form of 'sequence-parallel' XML formation
encapsulating behavioral description. The obtained behavioral
description encapsulated within the 'sequence-parallel' formation then
represents the specification of temporally defined shapes represented
by a 'UNIT' tag. When the PI units' attributes (rhshape, rashape,
lhshape, and lashape) are set (not 'None'), then each of them represents
one 'UNIT' tag, starting with the ' name' attribute. This attribute
describes a gesture affiliate. By using it, the animation engine can
easily recall the movement controllers defined as manifesting the
synthetic shape. The temporal specification of the 'UNIT' is provided
by specifying the following two obligatory EVA-SCRIPT-based
attributes. The ' durationUp ' attribute represents absolute temporal
value when describing how long it takes for the specified shape
to be fully overlaid on the synthetic agent (e.g. the duration of the
transition between shapes). It is equivalent to the PI's duration-up
attribute. And the persistence attribute determines for how long,