broadband multimedia

8/2/2019 Broadband Multimedia

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Broadband Multimedia e-learning system

using Web Service

Jie Wu Shiyong ZhangDept. of computing and information technology Dept. of computing and information technology

Fudan University Fudan University

Han Dan Road 220,Fudan,Shanghai,China Han Dan Road 220,Fudan,Shanghai,China

86-21-65643189 86-21-65643189

[email protected] [email protected]

Abstract:

The purpose of the paper is to research a new

broadband multimedia e-learning system using web

service. How to use web service to help broadband

multimedia e-learning courseware discovery, delivery,

access and service are the main issues, they are mainly:

intelligent broadband multimedia courseware

registration, broadband multimedia courseware

discovery method, broadband multimedia courseware

delivery, e-learning activities management . The

research will greatly resolve the problems in

broadband multimedia e-learning system.

Keywords

e-learning, web service, broadband multimedia

1. INTRODUCTION

E-learning is a fast growth application in the

world, it is widely used in universities, enterprises,

communities, and over one million users now are

learning through it. As a typical technical-driven

application, the development of e-learning has close

relationship with IT technologies such as computer

network, multimedia technology and etc. The

mainstream of e-learning systems now are mostly

server-centric based, users access the same e-learning

servers to get served (view courseware, have some

quiz, discuss etc), and the user-interfaces are mainly

web based for convenience. That kind of e-learning

system runs well while the number of user is not so

large, and the content user access is mainly web page

based.

With the development of e-learning, it appears

some new requirement:

The number of users increase fast, the load of

the e-learning server make the system slower

and the risk of crash increases. E-learning

system needs a new method to balance the load.

Users are more scattered. More users are

cross-state and cross-province, the low-speed of

internet results poor user experience. E-learning

users hope to have the same user experience as

they are in the same city.

With faster last-mile access including ADSL,

cable modem and FTTX+LAN, users can now

access a much broader range of multimedia

content, including audio, video, film, as well as

text, image and picture and more. E-learning

users of course will ask for more vivid

courseware in e-learning to help their learning.

The centralized model of current e-learning

system is not able to resolve the problems and

requirements listed above. In fact, the telecom carries

now are deploying CDN system to resolve some

broadband multimedia content delivery and service

problem, the work is something like but broadband

multimedia enabled e-learning system is more

complex.

In next section, we will discuss the architecture

of broadband multimedia enabled e-learning system

using web service, the section 3, some key issues of

system will discussed and in section 4 we will have a


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conclusion.

2. ARCHITECTURE

Main e-learning ServerMindSpring

PSINetSprint

Gloobix

QWest

@Home

UUnet

Fewer Requests

Fast Response

Clients

Clients

Clients

Sub e-learning system

Figure1. t opology of broadband e-learning systemFigure1. t opology of broadband e-learning system

Sub e-learning system Sub e-learning system

The problem issued before seems could be

solved by setting some mirror sites, in fact, mirror site

solution will meet other difficulties:

E-learning system is an integrated system, the

user activities is collected and monitored by

LMS( Learning Management System), a

efficient way should used to pass the users

activities of mirror sites LMS to original

server, to keep the consistency.

Broadband Multimedia courseware is so

storage-consuming, each mirror site should use

the same large storage to store the courseware,

and in fact, it is not so necessary, large storage

resource will be wasted if no dynamic content

discovery and delivery method is used.

To solve the problem, We propose to use web

service to construct a broadband multimedia enabled

e-learning system as shown in Figure1.

The new model of e-learning system is a

distributed e-learning system, web service is used to

coordinate the main e-learning system and sub

e-learning system. In the architecture, main e-learning

system contains the full function, service and content,

sub e-learning system contains partial function,

service and content, sub e-learning system can provide

service to end users along, also its a part of the whole

e-learning system.

Users access the same portal in the main

e-learning system, the main e-learning system in

charge of the central service such as authentication,

noticing, etc. When a user require a service that could

provide by the sub e-learning system, the request will

be redirect to the near sub-server. In broadband

environment, the service of on-line courseware

viewing will be provided by the sub-server, and the

activities of user will pass back to the main server by

SOAP of Web Service.

Broadband multimedia courseware of each

sub-server differs, usually, when the sub-server finds

that the courseware user requires does not in local

storage, it will communicate with the main server, and

a copy of the courseware will download to the sub

server, so the successor will get served with local


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sub-server, in the same time, the main server will

assign the nearest server to serve the user.

The architecture of new e-learning system will

benefit us as following:

Get served using near sub-server to have a better

QoS

Increase the availability of service

Few cost in system construction

3. KEY ISSUES OF SYSTEM

The key issue of the new broadband multimedia

enabled e-learning system is web service, the model

of web service is as the figue2.

ServiceRegistry

Service

Requestor

Service

provider

Publishfind

Bind

SOAP on HTTP

Figure2. Web service model

3.1 courseware & service

In order to take advantage of web service, the

courseware should be innovated to service. The

following is a sample of SCORM based courseware

description:

-

-

zh

-

CCNA

Demo

+

+

+

+

+

+

+

In the schema, there is a field of

identifier, in SCORM, the format of identifier is not

defined, so we can define identifier as UDDI in our

e-learning system.

3.2 courseware registration and

Discovery

As each courseware has a UDDI to identify, the

courseware should registrate in the main e-learning

system, main server also maintain a list of resource

that sub server contain, when user ask for some

resource( courseware), the main server will find out

the best sub server to server. The process of

courseware registration and discovery is shown as

figure3.

JavaApplication

User

Web servers hostingWeb Application, Web

Services Client

Server Hosting Web

Service

Broker UDDI Registry

(Yellow Pages For

Services)

Browser User

Request

Response

Publish

Request

Response

LookupResult

UCOPBencomWeb Service.NET or Java

UCOP or UC UDDIRegistry

Figure3. Courseware r egistr ation and discovery model

3.3 courseware router and delivery

Courseware will not always in the nearest sub

server of user, so it is important to make courseware

router and delivery. If the courseware does not appear

in the proper server, the users request will rout to the

next server that could provide the best service, also,

the courseware will deliver to the nearest server that

lack of it to prevent the later unsuccessful access.

Using courseware router and delivery, the consuming
http://d/DemoCCNA%20Demo%22http://d/DemoCCNA%20Demo%22http://d/DemoCCNA%20Demo%22http://d/DemoCCNA%20Demo%22http://d/DemoCCNA%20Demo%22http://d/DemoCCNA%20Demo%22http://d/DemoCCNA%20Demo%22http://d/DemoCCNA%20Demo%22http://d/DemoCCNA%20Demo%22http://d/DemoCCNA%20Demo%22http://d/DemoCCNA%20Demo%22http://d/DemoCCNA%20Demo%22http://d/DemoCCNA%20Demo%22http://d/DemoCCNA%20Demo%22http://d/DemoCCNA%20Demo%22http://d/DemoCCNA%20Demo%22http://d/DemoCCNA%20Demo%22http://d/DemoCCNA%20Demo%22http://d/DemoCCNA%20Demo%22http://d/DemoCCNA%20Demo%22


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of bandwidth will decrease greatly also the QoS of the

user will improve.

3.4 Activities Management

Users access the e-learning system in the same

portal of main e-learning system, the LMS of main

e-learning system create an instance for each user, if

the user is redirect to the sub server later, the LMS of

sub server will take it over and record the activities of

the user. After the user finish the activities in sub

server, the user activities will pass to the main server

using SOAP and finally merge in one activity record.

4 CONCLUSION

In this paper, we address the problem occurs in

broadband multimedia environment of e-learning

system. How to implement broadband multimedia

e-learning courseware discovery, delivery, access and

service are the main issues. The problem are not able

to be solved easily only improving the power of server

or bandwidth of network, a new architecture should be

used to solve the problem. We introduced a new

distributed e-learning architecture using web service

in broadband multimedia environment. We also

present the key issues of the system, they are mainly:

intelligent broadband multimedia courseware

registration, broadband multimedia courseware

discovery method, broadband multimedia courseware

delivery, e-learning activities management . The

research will greatly resolve the problems in

broadband multimedia e-learning system.

4 REFERENCES

1.W3C Recommendation " Extensible Markup

Language (XML) 1.0 (Second Edition)", Tim Bray,

Jean Paoli, C. M. Sperberg-McQueen, Eve Maler,

6October2000 .http://www.w3.org/TR/2000/REC-xml-

20001006.

2.SOAP Version 1.2 Part 1: Messaging Framework,

W3C Recommendation, M. Gudgin, M. Hadley, N.

Mendelsohn, J-J. Moreau, H. Nielsen, 24 June 2003

(See

http://www.w3.org/TR/2003/REC-soap12-part1-20030

624/.)

3.SOAP Version 1.2 Part 2: Adjuncts , W3C

Recommendation, M. Gudgin, M. Hadley, N.

Mendelsohn, J-J. Moreau, H. Nielsen, 24 June

2003(See

http://www.w3.org/TR/2003/REC-soap12-part2-20030

624/.)

5.[SCORM]SCORM Version 1.3 Application Profile

Working Draft Version 0.9. Retrieved

December 12, 2002 from

http://www.adlnet.org/adldocs/Other/SCORMV1.3_Se

qAppProfile.zip

6.[IMS LEARNING DESIGN] IMS Learning Design

Best Practice and Implementation

Guide. Retrieved May 14, 2003 from

http://www.imsglobal.org/learningdesign/ldv1p0/imsl

d_bestv1p0.html

7.[IEEE]Learning Technology Standards Committee

(2002). IEEE P1484.12 Learning Object

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2002, from Institute for Electrical and

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http://ltsc.ieee.org/wg12/index.html
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