Graphics Programs Reference
In-Depth Information
Evaluation of the Prototype
results clearly indicate (i) to use a resolution of
1600 x 1200 pixels (i.e. 2.1 Mpixel), (ii) to avoid
using the flash, (iii) that colors look better on a
blackboard than on a whiteboard, and (iv) to use a
camera that can be controlled by software. Regard-
ing the webcam, a resolution of 320 x 240 suffices
to have a decent view and frame rate (25fps). Tests
also pointed out that it is even possible to capture
a film that is shown on the classroom television.
Concerning audio, the pupil easily can make
use of a headset or the microphone integrated into
the webcam. The teacher is advised to use a wire-
less microphone together with fixed speakers. This
requires the need for acoustic echo cancellation
(AEC), either incorporated in the microphone or
in the software.
The personal computer itself only needs to
have a 3D accelerator graphics card in order to
fluently visualize the 3D environment.
Regarding bandwidth, the real bottleneck is
streaming live audio and video. Our tests pointed
out that when using the H.263+ codec (Bormann
et al., 1998) for compressing video (comprised of
320 x 240 pixels at 25Hz), 128kb bandwidth is
needed. This is quite acceptable as most people
and schools in the Flemish setting own an xDSL
or cable connection (download speed: 4.4-6Mb
upload speed: 192-256kb).
Despite some obstacles (i.e. connectivity and
technical problems), the application was used at
least three times (case 5) and in the other cases
it was used daily.
In all cases, the tool was used for socializa-
tion purposes. Only the oldest kids used it many
times and initiated these contacts once in a while.
Furthermore, in most cases the available syn-
chronous functionalities of the tool were used to
do so (except for case 4). In cases 2, 3 and 5 an
increase in social contacts was reported. As the
girls in trial 1 and 4 were able to attend school
on a daily basis (e.g., in the morning) during the
trial, the tool might be more important with regard
to socialization opportunities for children being
absent at school for longer periods in time.
The ability of the tool to offer more variety
in curriculum subjects seems to be related to the
availability of main subjects in home or hospital
education. The tool was predominantly used for
main subjects in all cases, however, in the case
with primary school children courses are added
to the core curriculum of homebound instruction
by using the tool.
In most cases, the use of the tool offered the
participating child an increase in didactical strate-
gies used as compared to the amount of strategies
used in home or hospital education (case 1, 2,
3 and 5). In case 4 not the features of the tool,
but the ignorance of the teacher led to a narrow
use of the tool in terms of didactical strategies.
However, in cases 2 and 3 the teachers did not
positively evaluate group-based strategies using
the tool. This was due to problems with class
management (case 2) and technical problems
such as the limited quality of the audio stream to
follow a class discussion (case 3).
DISCUSSION
Both the IDI-model for instructional design and
the design model of Passerini & Granger (2000)
are iterative models. This means that findings of
the evaluation phase could lead to revisions at
all other phases at any moment during the design
process. Although we presented the design of our
prototype as a linear design process in the present
article, revisions - initiated by evaluation findings
- were made to the prototype.
For example, during the first field trials (design
phase IV) it became clear that the sound in the
classroom when the sick child wanted to attract
Hardware Recommendations
In the classroom, a digital camera is employed
in order to take snapshots of the blackboard. The
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