Dynamic Content Synchronization Between Learning Management System Over Limited Bandwidth Network

Royyana M Ijtihadie, Bekti C Hidayanto, Achmad Affandi, Yoshifumi Chisaki and Tsuyoshi UsagawaHuman-centric Computing and Information Sciences, 2:17.http://www.hcis-journal.com/content/2/1/17

Presented by: Fajar Purnama 152-D8713

Graduate School of Science and TechnologyComputer Science and Electrical EngineeringKumamoto University

Outline

About

Introduction

Related Works and Contribution

Concept

Experiment and Evaluation

Conclusion and Future Works

Keywords

Dynamic Content SynchronizationDistributed Learning Management SystemsCourse SharingUnidirectional Content SynchronizationLimited BandwidthDeveloping CountryAdding the update button on contents in LMS.For bandwidth efficient content sharing and support in collaborative content development.Demonstrated on Moodle 1.9.KEY WORDS1 About

Today ICT Greatly Supports Education

2

IntroductionNot to forget, our daily lives changes as well!PhoneRadioTVGadgetsComputerThe Internet

Conventional face to face, text booksRadio and TV educationInformation Communication Technology comes in.Electronic Documents, Image, Videos, Presentation SoftwaresThe Internet: wikis, blogs, multimedia contents, social medias, interractive web pages, lot's and lot's of informations accessible to all. Learning Management System (LMS): course or lectures online, etc

Motivation

2

Introduction

More advance civilization and richer learning contents.

How to equally distribute the learning contents? (quality education for all)The west tends to be more advanced.How well contents are designed determines the success of e-learning.Is it easy? Resource, effort, time, experience is need to make such a well designed content.Why not share and collaborate? And then..

Looks like we need to revise the contents.Content's UPDATEDOhh NO...

Related Works

3 Related Works Moodleshare website offers course sharing in moodle course format.

Communityhub offers some people's developments in learning contents

They tended to be static. For example backup and restore function backups the entire course and let others restore them. In other words a whole content needs to be downloaded.Not much of a hazel if the size is small, but if most contents tends to be updated frequently. Usually it gets bigger with each updates. Should re-download the entire course everytime update occurs?

Contributions

3 ContributionsEven with high speed connection is annoying to re-download and re-install.

For me and the author's case we came from Indonesia where today's average Internet connection is 1 Mbps, not to mention there are still areas not penetrated by ICT.

The authors provided a novel method for sharing e-Learning, content between distributed LMS by using dynamic content synchronization.

Here we just need to obtain (download) the updated part. (Like most softwares with versionsespecially anti virus softwares)Centralized LMS is not good for us. Instead it's distributed.

4 ConceptContent Synchronization

Master LMS: The one who gives updates.Slave LMS: The one who receives updates.Uses Moodle LMS which is written in PHP and uses Mysql.Differential delivery is employed to distribute the modified part by finding the differential between the previous version of content with the new version.Hash table has been widely used in computer science as well, mainly for quick search of things in each of different value, and is able to identify certain locationMoodle table is converted into sync table which consist of ID, Content, and Hash.

Version matching is carried out using MD5 hash algorithm which is meant to detect whether modifications at the other end are already in place. No need to continue if version matches.

Modifications have several possibilities: addition, deletion, or modification. Determining the differential between the 2 LMS is carried out.

The final sync packets will be send from master to slave LMS sync table and converted into Moodle table.

4 Concept

RevisionRequesting update from CRequesting update from A

4 Concept

4 ConceptDetailed Script

r_chgs = [ ]; r_tsi = tsi; r_tsh = tsh; l_diff = diff(tmi,r_tsi)foreach id in l_diffr_chgs = r_chgs + ( id,append,tm[id] )r_tsh[id] = tmh[id]end forr_diff = diff(r_tsi,tmi)foreach id in r_diffr_chgs = r_chgs + (id,delete,)delete r_tsh[id]end for

if (r_tsh not equal tmh) thenforeach id in tmhif (tmh equal r_tsh) thencontinueend ifr_chgs = r_chgs + (id,update,tm[id])end forend if

r_chgs: all changes (final sync packet)ts: slave table, tm: master tablei: ID, h: hash, r: remoteSee whether an ID exist in master but not in slave. This mean an addition takes place and new content should be added (append).

Reverse, see whether an ID exist in slave but not in master. The content should be deleted (delete).

Check consistency of hashes, apply modification to match slave to master (update).

Sample Course

5 Experiment

Before

After

update

update

The Experiment

5 Experiment

NOActivity at Master

1New content: content doesn't exist in slave, Large bandwidth consumed.

2No changes: only conduct version checking, very small bandwidth consumed.

3Section order change: change order of materials, etc, small bandwidth consumed.

4Additional Labels: more labels or links to other resources, small bandwidth consumed.

5Additional information on certain content: new materials, etc, medium bandwidth consumed.

Update Scenarios

The Result

5 EvaluationData Rate measurement in kbps

ActivityWINDS DLWINDS ULInternet DLInternet UL

132200.0443.983.20

21 9.320.1394.66

39.8 6.1014.6653.80

412.5 7.1220.3050.50

566.5 0.3851.22464

Functionally the synchronization works.

On activity 1 shows high DL because getting all the contents.

On activity 2 shows high UL because checking the consistency between slave and master.

On activity 3 show low DL and UL because no significant changes.

On activity 4 is similar to activity 3.

On activity 5 shows medium DL because of additional material.

6 ConcluseionAn approach for unidirectional dynamic content synchronization between LMSs is discussed. This approach was evaluated by experimental connections between distributed LMSs to realize a distributed e-Learning environment. The experiments show that this
system works well, and is capable of doing content synchronization between Learning Management Systems efficiently.

6 Future

WorksBandwidth concerns in some parts of the world may still remain in the immediate future. Therefore, a further approach for delivering content updates in dynamic content
synchronization in an efficient manner still needs to be considered. In this regards, e-mail system capability to deal with separated network (sender and recipient do not need to be
in direct path route) making it potential to deliver the differential updates over unstable
network channel infrastructure.