A Grid Approach to Provide Effective Awareness to On-line Collaborative Learning Teams

A Grid Approach to Provide Effective A Grid Approach to Provide Effective Awareness to On-line Collaborative Awareness to On-line Collaborative

Learning TeamsLearning Teams

by by Santi Caballe, Thanasis Daradoumis, Santi Caballe, Thanasis Daradoumis,

Claudi Paniagua and Fatos XhafaClaudi Paniagua and Fatos Xhafa

1st International Workshop on Distributed e-Learning Environments

14th of March 2005

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IndexIndex

IntroductionIntroduction:: thethe importance of providing effective importance of providing effective awareness to on-line collaborative teams.awareness to on-line collaborative teams.

Knowledge of group and individual activity,

and coordination are central to successful

cooperation. These factors are clearly critical

concerns in the design of computer systems […]

P. Dourish & V. Bellotti (1992)

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IndexIndex

IntroductionIntroduction: : thethe importance of providing effective importance of providing effective awareness to on-line collaborative teams. awareness to on-line collaborative teams.

Approach:Approach: need for structuring and processing of need for structuring and processing of large amounts of group activity information.large amounts of group activity information.

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IndexIndex


Approach: need for structuring and processing of Approach: need for structuring and processing of large amounts of group activity information.large amounts of group activity information.

Problem:Problem: lack of computational resources. lack of computational resources.

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IndexIndex



Problem: lack of computational resources.Problem: lack of computational resources. Solution:Solution: a Grid-based approach to process a Grid-based approach to process group group

activity information through an application of the activity information through an application of the Master-Worker paradigm using Planetlab platform.Master-Worker paradigm using Planetlab platform.

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IndexIndex



Problem: lack of computational resources.Problem: lack of computational resources. Solution: a Grid-based approach to process Solution: a Grid-based approach to process group group


Experimental results:Experimental results: the benefits of a parallel the benefits of a parallel processing approachprocessing approach

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IndexIndex


Approach: the process of creating awareness.Approach: the process of creating awareness. Problem: lack of computational resources.Problem: lack of computational resources. Solution: a Grid-based approach to process Solution: a Grid-based approach to process group group


Experimental results: the benefits of a parallel Experimental results: the benefits of a parallel processing approachprocessing approach

ConclusionsConclusions and future work. and future work.

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Introduction (I)Introduction (I) Providing awareness to on-line learning teamsProviding awareness to on-line learning teams

Awareness of co-learners’ activities is essential to achieve Awareness of co-learners’ activities is essential to achieve a successful cooperation, in terms ofa successful cooperation, in terms of implicit coordinationimplicit coordination collaborative learningcollaborative learning informal and spontaneous communicationinformal and spontaneous communication

Awareness allows tutors to track the collaborative learning Awareness allows tutors to track the collaborative learning process for several purposes such asprocess for several purposes such as scaffoldingscaffolding assessmentassessment monitoringmonitoring

Awareness enhances the collaboration in great deal in terms Awareness enhances the collaboration in great deal in terms of decision-making, social engagement, support and so on.of decision-making, social engagement, support and so on.

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Introduction (II)Introduction (II) Providing awareness to on-line learning teamsProviding awareness to on-line learning teams

During the collaboration, learners need to be aware of what During the collaboration, learners need to be aware of what others are doing at the same time and what they did in the others are doing at the same time and what they did in the past. This implies that awareness can be done in both modespast. This implies that awareness can be done in both modes

synchronous:synchronous: to provide real-time information (e.g. co-members to provide real-time information (e.g. co-members location and availability, who is doing what, etc.).location and availability, who is doing what, etc.).

asynchronous:asynchronous: to provide deferred information (e.g. who, when, how to provide deferred information (e.g. who, when, how and where a shared resource has been created, changed, read, etc.). and where a shared resource has been created, changed, read, etc.).

Supplying effective and transparent awareness to users in Supplying effective and transparent awareness to users in both modes is a significant challenge sinceboth modes is a significant challenge since

users interact with the system all the time and generate a great users interact with the system all the time and generate a great amount of information.amount of information.

this information may include a great variety of types and formats.this information may include a great variety of types and formats. the information collected needs to be classified, processed and the information collected needs to be classified, processed and

analyzed and make the analysis results available even in real time.analyzed and make the analysis results available even in real time. This requires processing capacity beyond a single computer.This requires processing capacity beyond a single computer.

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IntroductionIntroduction (III) (III)ContextContext

Group activity at Open University of Catalonia involves Group activity at Open University of Catalonia involves hundreds of students and dozens of tutors in several on-line hundreds of students and dozens of tutors in several on-line courses.courses.

The complexity of the learning practices entails intensive The complexity of the learning practices entails intensive collaboration activity.collaboration activity.

BSCW is used as a groupware system to capture group BSCW is used as a groupware system to capture group activity interaction in log files.activity interaction in log files.

BSCW does not provide log file processing nor statistical BSCW does not provide log file processing nor statistical analysis capabilities.analysis capabilities.

BSCW generates a huge daily single log file and does not BSCW generates a huge daily single log file and does not

classify nor structure data in any way.classify nor structure data in any way.

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Approach (I): The process of creating awarenessApproach (I): The process of creating awareness

The whole pictureThe whole picture

Four stages in information management: Four stages in information management: Classification, processing, analysis and presentation.Classification, processing, analysis and presentation.

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Approach (II): The process of creating awarenessApproach (II): The process of creating awareness

Stage I: ClassificationStage I: Classification

Collection of information.Collection of information. Extraction of actions.Extraction of actions. Identification of events.Identification of events. Categorization according toCategorization according to

• Learning productLearning product• Group functioningGroup functioning• ScaffoldingScaffolding

Store as system log files.Store as system log files.

Classification in synchronous environments is very similar.Classification in synchronous environments is very similar.

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Approach (III): The process of creating awareness Approach (III): The process of creating awareness

Stage II: ProcessingStage II: Processing

Obtain event information from Obtain event information from large log files.large log files.

Process log files according to Process log files according to desired criteria. e.g.desired criteria. e.g.• timetime• workspaceworkspace

Store processing results in a Store processing results in a suitable database.suitable database.

Processing of events needs great computational power.Processing of events needs great computational power.

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Approach (IV): The process of creating awareness Approach (IV): The process of creating awareness

Stage III: AnalysisStage III: Analysis

Need for extracting Need for extracting complex knowledge from complex knowledge from the database.the database.

Define consulting criteria.Define consulting criteria. Send criteria and data to Send criteria and data to

external statistics package.external statistics package. Obtain useful statistical Obtain useful statistical

results from the analysis.results from the analysis.

External analysis offers the best existing statistical package.External analysis offers the best existing statistical package.

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Approach (V): The process of creating awareness Approach (V): The process of creating awareness

Stage IV: PresentationStage IV: Presentation

Predefine an XML coding to Predefine an XML coding to represent represent ad hocad hoc statistical statistical measurements.measurements.

Structure statistical results Structure statistical results into XML output.into XML output.

Convert XML into desired Convert XML into desired presentation format. presentation format.

Present results to users.Present results to users.

Users receive knowledge as awareness information.Users receive knowledge as awareness information.

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Statement of the problem (I) Statement of the problem (I) Need for processing of event informationNeed for processing of event information

Real on-line environments with a large number of Real on-line environments with a large number of students and tutors that are geographically students and tutors that are geographically distributed.distributed.

High degree of user-user and user-system High degree of user-user and user-system interaction generates lots of event information.interaction generates lots of event information.

Constant provision of awareness to group Constant provision of awareness to group participants in real-time.participants in real-time.

Essential to monitor, track and evaluate real, Essential to monitor, track and evaluate real, complex, long-term, collaborative problem-solving complex, long-term, collaborative problem-solving situations. situations.

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Statement of the problem (II)Statement of the problem (II)Lack of computational resourcesLack of computational resources

Need for processing of a huge amount of event Need for processing of a huge amount of event information gathered in single log files.information gathered in single log files.

Essential to dispose of the processing results of Essential to dispose of the processing results of group activity in real-time.group activity in real-time.

Event information in log files should be partitioned in Event information in log files should be partitioned in multiple log files according to particular needs.multiple log files according to particular needs.

Event information must be constantly processed in Event information must be constantly processed in an efficient manner during the processing stage.an efficient manner during the processing stage.

Lack of sufficient computational resources is the Lack of sufficient computational resources is the main obstacle to the constant processing of multiple main obstacle to the constant processing of multiple data log files in real time.data log files in real time.

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Obtain event information from Obtain event information from large log files.large log files.

Structure the information Structure the information according to particular needs.according to particular needs.

Create log files of different Create log files of different degrees of granularity.degrees of granularity.

Process all log files at the Process all log files at the same time. same time.

Store results in the database.Store results in the database.

Need for the processing of all log files to be parallelized.Need for the processing of all log files to be parallelized.

Solution (I)Solution (I)Redefining the processing stageRedefining the processing stage

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Solution (II)Solution (II)A Grid-based solutionA Grid-based solution

Grid technology provides broad access to massive Grid technology provides broad access to massive information and computational resources.information and computational resources.

In this context, Grid computing paradigmIn this context, Grid computing paradigm overcomes the lack of computational resources to process a overcomes the lack of computational resources to process a

large amount of event information.large amount of event information. allows processing of the log files taking advantage of the allows processing of the log files taking advantage of the

parallelism inherent in the distributed nature of Grid. parallelism inherent in the distributed nature of Grid. provides load balance in the processing of log files of different provides load balance in the processing of log files of different

granularity.granularity.

Master-Worker paradigm using Planetlab platform, a Master-Worker paradigm using Planetlab platform, a Grid-based approach for processing log files.Grid-based approach for processing log files.

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A Grid approach (I)A Grid approach (I)Master-Worker paradigmMaster-Worker paradigm

Distinguishes two types of processors:Distinguishes two types of processors: master:master: performs the control and coordination tasks. performs the control and coordination tasks. workers:workers: perform most of the computational work. perform most of the computational work.

Advantages:Advantages: flexibility: workers can be implemented in different ways.flexibility: workers can be implemented in different ways. scalability: workers can be easily added.scalability: workers can be easily added. separation of concerns: master does coordination and separation of concerns: master does coordination and

workers do specific tasks. workers do specific tasks.

Target: parallel applications with weak Target: parallel applications with weak synchronization and reasonably large grain size.synchronization and reasonably large grain size.

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A Grid approach (II)A Grid approach (II)A prototype for processing log files (I) A prototype for processing log files (I)

EventExtractorEventExtractor: extracting information from BSCW: extracting information from BSCW converts event information into well-formatted data.converts event information into well-formatted data. stores the extraction results in a database.stores the extraction results in a database. needs a lot of time to process sequentially.needs a lot of time to process sequentially.

MW model: appropriate in this context given thatMW model: appropriate in this context given that log files of different granularity are processed.log files of different granularity are processed. workers are not synchronized between them.workers are not synchronized between them. communication load between master and workers are low.communication load between master and workers are low.

Planetlab platform: using a real Grid environmentPlanetlab platform: using a real Grid environment by installing the Globus Toolkit 3 Grid service container,by installing the Globus Toolkit 3 Grid service container, and deploying the prototype on Planetlab. and deploying the prototype on Planetlab.

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A Grid approach (III)A Grid approach (III)A prototype for processing log files (II) A prototype for processing log files (II)

A minimal Grid implementation made up of:A minimal Grid implementation made up of: the the workerworker as a as a Grid service that does the main work by the next steps:Grid service that does the main work by the next steps:

• wraps the wraps the EventExtractorEventExtractor routine, routine,

• publishes an interface that the master calls in order to dispatch a task,publishes an interface that the master calls in order to dispatch a task,

• passes a string representation of the events to be processed, andpasses a string representation of the events to be processed, and

• returns a data structure containing performance information.returns a data structure containing performance information.After completion the task, the worker is put back into a queue of idle After completion the task, the worker is put back into a queue of idle

workersworkers the the mastermaster first obtains the event log file to be processed, the available first obtains the event log file to be processed, the available

workers, the task size to be dispatched to workers and the number of workers, the task size to be dispatched to workers and the number of workers to use that put in a idle queue. Then enters the next loop:workers to use that put in a idle queue. Then enters the next loop:

• reads a specific number of events from a event log file,reads a specific number of events from a event log file,• calls a idle worker and sends it the events to be processed,calls a idle worker and sends it the events to be processed,

The master exits the loop when all events in the current log file haveThe master exits the loop when all events in the current log file have

been read and all tasks to be dispatched have been finalized.been read and all tasks to be dispatched have been finalized.

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Experimental results (I)Experimental results (I)PreliminariesPreliminaries

An An ad hocad hoc test battery was designed made up of: test battery was designed made up of: exhaustive collection of log filesexhaustive collection of log files

• from the spring term of a course with 140 students arranged in 5-from the spring term of a course with 140 students arranged in 5-member groups and 2 tutors.member groups and 2 tutors.

a selected sample of a few log filesa selected sample of a few log files• as a representative stratum of file size and event complexity.as a representative stratum of file size and event complexity.

All test battery was processed by the All test battery was processed by the EventExtractor EventExtractor on single-processor nodes of Planetlabon single-processor nodes of Planetlab involving usual configurations.involving usual configurations. with different work load.with different work load. repeating the execution several times.repeating the execution several times.

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Experimental results (II)Experimental results (II)Parallel processing resultsParallel processing results

The parallel processing results were obtained by The parallel processing results were obtained by running tests for different task sizes and number of workersrunning tests for different task sizes and number of workers observing how much close each set of workers is to achieve its theoretic maximum speed-observing how much close each set of workers is to achieve its theoretic maximum speed-

up.up.

Relative speed-up for 5-event task and different number of workersRelative speed-up for 5-event task and different number of workers

Task Size = 5

0

0,2

0,4

0,6

0,8

1

1,2

2 4 8 16

Number of Workers

% o

f M

ax S

peed

-up

Ach

ieved

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Experimental results (III)Experimental results (III)Analysis of the resultsAnalysis of the results

Apart from very small task sizes, the speed up observed was very close to the maximum achievable.Apart from very small task sizes, the speed up observed was very close to the maximum achievable. The more workers used in our tests the closer to the maximum was the speed up achieved by the smallest tasks.The more workers used in our tests the closer to the maximum was the speed up achieved by the smallest tasks. Results were a little biased due to the homogeneous behaviour observed in Planetlab and they should be adjusted to Results were a little biased due to the homogeneous behaviour observed in Planetlab and they should be adjusted to

the dynamic workload of a real Grid.the dynamic workload of a real Grid. Event complexity is key to take advantage of the benefits of a Grid environment as BSCW system generates a very Event complexity is key to take advantage of the benefits of a Grid environment as BSCW system generates a very

few different types of events. few different types of events.

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Conclusions and future workConclusions and future work We have first argued how the provision of continuous awareness to on-line learning teams can greatly improve the group activity.We have first argued how the provision of continuous awareness to on-line learning teams can greatly improve the group activity. We have also shown that in the process of creating awareness there is a strong need for computational resources to process We have also shown that in the process of creating awareness there is a strong need for computational resources to process

large amounts of information. large amounts of information. According the results obtained in this study, the benefits of Grid enhances depending on the volume and complexity of event log According the results obtained in this study, the benefits of Grid enhances depending on the volume and complexity of event log

files to be processed.files to be processed. As ongoing work, we plan to improve our prototype in terms of communication master-workers, fault-tolerance and dynamic As ongoing work, we plan to improve our prototype in terms of communication master-workers, fault-tolerance and dynamic

discovery of idle workers. discovery of idle workers.

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Thank you !Thank you !

Questions?Questions?

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A Grid Approach to Provide Effective Awareness to On-line Collaborative Learning Teams