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Collaborative Learning by Distance Chorus on the Internet
1. Collaborative Learning by Distance Chorus on the Internet Takashi Kishida Graduate School of Information Sciences, Hiroshima City University
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4. Technical Issues We tried distance chorus using some existing TV conference systems ― We got a few technical issues ― Clear video and audio are required. Especially, audio is more important. Network delay is very serious. Existing video conference tools are not enough.
5. On Network Delay Place A Place B time Less than about 100 ms We need a new audio conference system the existing audio conference tools doesn't satisfy this condition Network Delay Network Delay
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8. Feature of MRAT About 140ms About 130ms About 70ms Implemented delay High Middle Low Robustness Reliable transmission Smooth interaction Audio synchronization (Short delay) Main requirement Any Less than 400 ms Less than 100 ms Allowable delay Distance lecture Audio conference Distance chorus Target Broadcasting Conversation Chorus Mode
9. Audio Quality of MRAT -> MRAT is almost same quality with FM broadcasting. -> Enough for music (chorus) ( Samples = 15 persons )
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11. Distance Chorus Hiroshima City Univ. Hakushima Elementary School ( Main melody ) Minami-Kanon Elementary ( Sub melody ) Experimental IP network 10Mbps, wide area Ethernet 70 ～ 75ms Accompaniment Accompaniment Accompaniment Sub melody Main+Sub melody Accompaniment +Sub melody Accompaniment +Main melody Main melody
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18. Distance Chorus Hiroshima City Univ. Hakushima Elementary School (Main melody) Minami-Kanon Elementary (Sub melody) Experimental IP network 10Mbps, wide area Ethernet 70 ～ 75ms 7 ms jitter 2.1 ms Transmission delay mono Channel 32kHz Sampling rate Linear-16 （ PCM ） Coding Accompaniment Accompaniment Accompaniment Sub melody Main+Sub melody Accompaniment +Sub melody Accompaniment +Main melody Main melody
19. To realize the Distance Chorus accompaniment Main melody Sub melody Ideal tolerant delay 70ms 140ms
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21. Distance Chorus Hiroshima City Univ. Hakushima Elementary School (Main melody) Minami-Kanon Elementary (Sub melody) Experimental IP network 10Mbps, wide area Ethernet 70 ～ 75ms Accompaniment Accompaniment Accompaniment Sub melody Main+Sub melody Accompaniment +Sub melody Accompaniment +Main melody Main melody
22. Impression of the Exchange (After the class) the distance class including a distance chorus was just one step of the whole study to improve communication ability rather than impact event
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