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Collaborative Learning by

Distance Chorus on theInternet

Takashi Kishida

Graduate School of Information Sciences,

Hiroshima City University

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Background Broadband networks

Multimedia communications

New learning style : Interactive distancelearning

Period for Integrated Study

To encourage communicationability

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Motives of DistanceChorus Is it possible to sing with other

students through the Internet?

Distance chorus is one candidate Expectations

More active collaboration for students thandistance learning

An effective chance for teachers andstudents to know the possibility ofmultimedia communications usingbroadband networks

A virtual experience to communicatestudents at remote locations sometimes

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Technical Issues

We tried distance chorus using someexisting

TV conference systems

Clear video and audio are required.

Especially, audio is more important.Network delay is very serious.

Existing video conference tools are not

enough.

We got a few technical issues

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On Network Delay

Place

A

PlaceB time

Less than about 100ms

We need a new audio conference system

Network Delay Network Delay

the existing audio conference tools

doesn't satisfy this condition

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MRAT

To achieve shorter delay

Development of a multipurpose audio

transmission system called as MRAT(Multipurpose RAT) MRAT was developed on the basis of RAT

RAT(Robust Audio Tool) is one of audioconference systems

Achievement of short delay and an errorcorrection mechanism to recover packetlosses

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Feature of MRAT

About 140msAbout 130msAbout 70msImplementeddelay

HighMiddleLowRobustness

Reliabletransmission

Smoothinteraction

Audiosynchronizati

on(Short delay)

Mainrequirement

AnyLess than 400ms

Less than 100ms

Allowabledelay

Distancelecture

Audioconference

Distancechorus

Target

BroadcastingConversationChorusMode

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Audio Quality of MRAT

0

3

69

12

15

Analog Phone AM broadcasting FM broadcasting Music CD

Audio Quality

Thenumberofanswer

MRAT is almost same quality with FMbroadcasting.

Enough for music (chorus)

( Samples = 15 persons )

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The exchange usingDistance Chorus

Practical experiment of distance chorusat two elementary schools.

Purpose

To improve communication ability Method

Pre-exchange Web chat (to introduce students

interesting of the partner school) Preparation of presentation to

introduce themselves

The exchange day Distance presentation

Distance chorus

1. Opening greetings

2. Introduction of eachschool

3. Exchange of eachschool song

4. Questions and

answers on each school5. Exchange of songs fora partner

6. Distance Chorus

7. Ending greetings

Flow of Exchange

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Hiroshima City Uni

akushima Elementary School(Main melody)

inami-Kanon Elementary(Sub melody)

Experimental IPnetwork

10Mbps, widearea Ethernet

7075ms

DistanceChorus

Accompaniment

Accompaniment

Accompaniment

Submelody

Main+Sub

melody

Accompaniment

+Sub melody

Accompaniment

+Main melody

Mainmelody

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Impression of the exchange(Before the class)

What is your expectation? Or what is yourworry?

0

20

40

60

80

100

120

140

Presentation Music performance Face-to-face

interaction

Introduction

thenumberofanswers

Positive

Negative

The same result would be obtained if the class was held

not in the case of using the network but in the case of

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Impression of the Children

I enjoyed the exchange.

I want to have this kind of class again,

and become more friendly with them.

Im glad to see the partner in spite ofdistance.

How did the partner feel to us?

Majority of thedescriptions

Interesting descriptions

The children had more interest in thepartnerActive collaboration seems to be

effective to improve communication

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Scalability of Distance Chorus

How wide area torealize distancechorus?

Lightpropagation:2100km in 70ms

Metropolitannetwork within anarea of a fewhundredskilometers.

Auckland

By this restriction

The mostideal

situation

Its realizable as a regional

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Conclusions

Development of a new system fordistance chorus.

An active collaboration overnetworks can be realized by usingbroadband networks and oursystem

Possibility of educationaleffectiveness through activecollaboration

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Future Problems

Improvement of MRAT such asadaptive control

New educational applications usingMRAT

Distance ensemble Volume control is difficult

Distance chorus at three schools

Additional Experiments

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Discussion (1)

Educational Purpose of Distance Chorus To encourage communication ability of the

children with the different schools

To give children a chance ofcommunications using the network

Impacts and Effectiveness of DistanceChorus An effective chance for teachers and

children to know the possibility ofmultimedia communications usingbroadband networks.

An active class is More effective than an

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Hiroshima City Uni

akushima Elementary School(Main melody)

inami-Kanon Elementary(Sub melody)

Experimental IPnetwork

10Mbps, widearea Ethernet

7075ms

7 msjitter

2.1 msTransmission

delay

monoChannel

32kHzSampling rate

Linear-16 PCM

Coding

DistanceChorus

Accompaniment

Accompaniment

Accompaniment

Submelody

Main+Sub

melody

Accompaniment

+Sub melody

Accompaniment

+Main melody

Mainmelody

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To realize the DistanceChorus

70ms

140ms

accompanimen

t

Mainmelody

Submelody

Ideal tolerant delay

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On Network Delay (2)

Tolerant delay in distance chorusshould be less than about 100msby repeating experiments.

New development for distancechorus:

MRATMultipurpose RAT

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Hiroshima City Uni

akushima Elementary School(Main melody)

inami-Kanon Elementary(Sub melody)

Experimental IPnetwork

10Mbps, widearea Ethernet

7075ms

DistanceChorus

Accompaniment

Accompaniment

Accompaniment

Submelod

y

Main+Sub

melody

Accompaniment

+Sub melody

Accompaniment

+Main melody

Mainmelody

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Impression of the Exchange(After the class)

0

20

40

6080

100

120

140

Usefulness of web-

chat?

Try again? Hope of real meeting

thenumbero

fstudent Positive

Fair

Negative

the distance class including a distance chorus wasjust one step of the whole study to improve

communication ability rather than impact event