Information Technology Reference
In-Depth Information
Videoconferencing
Approaches to Interaction
Streaming and Webcasting
Approaches to Interaction
Video has been used in distance learning for many
years (see Mood, 1995, for a review). It is particu-
larly useful in geographically distributed groups
because it facilitates both voice interaction and
some visual awareness of contextual information
(e.g., who else is present) and nonverbal cues (e.g.,
gaze direction, facial expressions, raised hands)
(Clark & Brennan, 1991), which are important in
face-to-face classrooms, as described above, in
that they allow for more natural interaction, and
improve the capacity for mutual understanding
(Clark, 1996).
With this in mind, Chen (2001, 2002, 2003)
sought to enhance basic two-way interaction by
providing augmented awareness of student and
presenter gaze direction and eye contact (Chen,
2001), and of student participation patterns (Chen,
2003). While this experience highlights the im-
portance of the awareness questions we explore,
this system, like other videoconferencing systems,
restricted participation by using high-bandwidth
technologies and specialized sensors.
While current video technologies mean that
only an ordinary Internet connection is required
to participate in a basic videoconference, there are
frequently quality issues with performance and
reliability that can impede frequent and natural
interaction (Anderson, et al., 2000). Still, there are
tools such as Microsoft's Conference XP (Need-
ham, 2006), the ISABEL project (http://isabel.
dit.upm.es/), and the satellite system described
by Serif et al. (2009) which can all yield good
results when bandwidth and network quality are
favorable.
Indeed, videoconferencing provides many
benefits, but restricts participation to those with
available bandwidth and other resources; and
also restricts participation to the number of si-
multaneous participants that can be supported in
a conference, which is often lower than is possible
in a webcast.
A second approach to distributed lecture-style
presentations is to use one-way streaming media.
Isaacs et al. (1994) developed an early system to
support streaming presentations, and many of the
features of their system persist in what are now
called webcasting technologies (Weinstein, 2005).
These technologies allow for transmission of some
combination of audio, video and presentation
media (e.g., slides). Webcasting uses streaming
technologies, which support many simultaneous
users and use buffering to ensure relatively high
reliability. At the same time, however, these ad-
vantages can make awareness and interaction a
difficult problem.
ePresence (http://epresence.tv), an open source
webcasting infrastructure, improved on basic
webcasting by supporting the transmission of
presentation media along with streaming video
and audio, and offering two-way text interaction
between the presenter and audience (Ron Baecker,
2003). We describe the modified ePresence system
used in this study below.
Others have also sought to improve the speak-
er's awareness of remote attendees in webcasting.
The TELEP system developed by Jancke et al.
(2000), for example, was used to webcast live
presentations on the Microsoft campus to those
who did not wish to leave their offices to attend. To
facilitate awareness, it allowed remote attendees
to share webcam video or still images of them-
selves, which were displayed on the wall of the
presentation space within view of the speaker and
face-to-face attendees. Remote attendees could
ask questions via a text chat interface.
In using TELEP, however, many remote at-
tendees did not share video images of themselves,
reportedly because many were multitasking and
did not want the speaker to see that they were
focusing only intermittently on the presentation.
As the system was used only on the Microsoft
campus, remote attendees were not physically far
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