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Using Script Command to Conquer the Narrowband Constraint in Synchronous Long-distance Teaching System |
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PP: 685S-695S |
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Author(s) |
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Wei-Chih Hsu,
Cheng-Hsiu Li,
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Abstract |
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| The applications of synchronous long-distance teaching (SLDT) are more and more
valuable with the internet prevalence. One of the SLDT restrictions is the bandwidth consumption of
the connection between teacher’s side and students’ sides. Even though most users use broadband
network at present, there are still users using narrowband networks, such as dial-up and 3.5G network.
It is very difficult to conduct SLDT in the narrowband network unless reducing the demands of
network bandwidth consumption, especially while the teaching materials including video, audio, and
so on. This paper proposes a novel scheme to reduce the network bandwidth requirement of SLDT
efficiently. Original SLDT system transmits all teaching materials in full screen frames, so that it
needs a great amount of network bandwidth. The proposed innovative technique encodes some of the
teaching materials, including typing texts, messages on the electronic whiteboard, drawing pictures
and timestamps into script commands. In this way, the encoded script commands are transmitted
through the text channel of the multimedia streaming, while the audio and video channels carry the
teacher’s voice and images. When the students’ sides receive the multimedia streaming, it is decoded
back to the full screen frames. In this paper, the design of the encoder and decoder will be addressed
in detail. The experimental results proved that our proposed scheme could reduce the demand of
network bandwidth consumption efficaciously. Even at the dial-up and 3.5G network environment,
students’ sides could play the teaching frames very smoothly. That is, our implemented system could
conquer the narrowband constraint and provide users to carry out SLDT in the narrowband network. |
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