DAISy Dynamic Ambient Intelligent Systems Unit

In this paper, the model and architecture of the multimedia subsystem
of a distributed authoring environment called VAS (Virtual Authoring
System) are presented. VAS is an authoring environment that integrates
various tools and provides a common communication basis for the tools
and yhe designers who use them. Its underlying model is based on
existing actor models, implementing all the society- modeling
capabilities these models exhibit, while the Client Facilitator
Consultant model is used to model the systemwise tool behaviour. The
Multimedia Distributed Filing System (MDFS) of VAS meets many
requierements users have from multimedia systems and uses VAS model to
provide system users with transparent access to multimedia objects.
MDFS consists of many co- operating servers, which implement VAS actor-
based model. To take advantage of many well- established standards,
MDFS communications have been implemented upon the Berkeley Unix socket
library. The distributed nature of VAS offers a new perspective to the
authoring process and the system's object- oriented model has led to an
open- ended architecture, which permits the integration of new tools
and supports the system's evolution to meet new emerging requierements.