Graphics Programs Reference
In-Depth Information
needs with regard to formal instruction. In fact,
children suffering chronic or long-term illnesses
often lack even more the socialization opportuni-
ties offered at school. All functionalities mentioned
earlier are assumed to contribute to their socializa-
tion too. Most teachers and children interviewed
in design phase II indicated that the synchronous
functions of audio and video chat are enough to
fulfill the social needs. On top of this, a classroom-
present device was built (Figure 4(a)), in order to
foster social inclusion in the classroom as much
as possible. The main design philosophy of this
hardware device was to give the remote child a
general feeling of presence in line with the sug-
gestion of some participating children “to place
the tool at their personal desk in the classroom”.
Using a simple game controller, the sick child can
rotate the device in order to look around. Finally,
our system tries to fulfill the need expressed by
some children to play during school breaks by
offering the opportunity to join lifelike party games
and by integrating links to online games, all set
in a playful environment.
mode (e.g., video-chat, attending classes). Given
the real-time nature of these data streams, it is
obvious to choose the Real-Time Transmission
Protocol or RTP as underlying protocol because
it handles issues such as synchronization and
packet ordering internally (Schulzrinne et al.,
2003). Finally,
Data Transfer Management
takes
care of transporting data in asynchronous mode
such as file transfer and audio/video mails.
Each of these tasks is handled by dedicated
servers. The session server takes care of logging
on/off and authenticating users. In addition, it is
also being used to initialize audio/video com-
munication sessions and to set up file transfers.
In order to manage all sessions, the 'Session Ini-
tiation Protocol' (SIP) is used (Rosenberg et al.,
2002). Whenever synchronous communication is
needed between two parties, audio and video can
be exchanged peer-to-peer. When multiple parties
are involved one single stream is sent to the com-
munication server which relays it to the different
parties. The VIC server takes care of the entire 3D
virtual environment. This involves transmitting the
world itself, synchronization between the clients
and always storing a persistent world. The data
server is used for two categories of asynchronous
data. On the one hand, it stores configuration files
of the users containing personal information such
as audio/video parameters and address lists of the
community. On the other hand, the server makes
it possible to transmit and store (shared) media
and files in asynchronous mode. To this end we
employed Hypertext Transfer Protocol (HTTP)
and File Transfer Protocol (FTP).
Network Architecture
The network architecture of the developed tool is
made up of several tasks and the corresponding
servers used to complete these tasks. Both tasks
and servers will be briefly discussed (see also
Figure 7).
When starting up the software,
Session Man-
agement
starts to run. It is mainly responsible for
logging on/off users and taking care of authenti-
cation. After logging on, the user can navigate
through the virtual world by means of an avatar.
At any moment, all users are being informed of
each other's presence (i.e. position, mood, activ-
ity, etc.) but also of any obstacles in the world.
This is managed by
VIC Interaction Management
.
Communication Management
is responsible for
distributing multimedia content in synchronous
DeSIgN PHASe IV: eVALUATION
OF THe PROTOTYPe
In order to evaluate our system, field trials have
been set up with the future target audience within
authentic settings.
Search WWH ::
Custom Search