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A Case Study on Merging Strategies for Authoring QoE-based Adaptive Hypermedia

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jscotton

This document presents a case study on merging multiple adaptation strategies for authoring adaptive hypermedia. It identifies common problems that can occur when combining strategies, such as variable clashes and type conflicts. The document proposes a method for addressing these issues by defining adaptation behaviors as separate strategies and using a meta-strategy to control strategy execution. It applies this method to a case study involving quality-of-service and media-mixing adaptation strategies, defining individual strategies for setup, quality-of-service adaptation, and media-mixing adaptation.

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A Case Study on Merging Strategies for Authoring QoE-based Adaptive Hypermedia Joshua Scotton, S. Moebs, J. McManis, A. I. Cristea jscotton@dcs.warwick.ac.uk September 29th, 2009
A Case Study Multiple Adaptation Behaviours Combining Multiple Adaptation Strategies Ease of Reuse and further Modification
Outline Overview of the Technology General Problems with Combining Strategies A Proposed Method Application to the Case Study
CAF + LAG Presentation Model Adaptation Model User Model Goal Model Domain Model
Quality of Experience (QoE)
Strategy for Quality of Service (QoS) Adaptation of content based on Network Conditions 1 Assess network conditions 2 Map these to a performance profile 3 Use the profile to select the content
Strategy for Quality of Service (QoS) implementation( if(enough(PM.bandwidth_profile <= PM.loss_profile PM.bandwidth_profile <= PM.delay_profile PM.bandwidth_profile <= PM.jitter_profile,3)) then (PM.QOS = 0) else (PM.QOS = (0.5 * PM.bandwidth_profile) + (0.5*((0.4*(PM.loss_profile + PM.delay_profile)) + (0.2 * PM.jitter_profile)))) if (PM.QOS <= 0.2) then ( if (GM.Concept.label LIKE *text*) then ( PM.GM.Concept.show = True ) ) else if (PM.QOS <= 0.5) then ( if (GM.Concept.label LIKE *audio*) then ( PM.GM.Concept.show = True ) ) else if (PM.QOS <= 0.8) then ( if (GM.Concept.label LIKE *video-low*) then ( PM.GM.Concept.show = True ) ) else ( if (GM.Concept.label LIKE *video-high*) then ( PM.GM.Concept.show = True ) ) )
Strategy for Media Mix Continual variation of Media Content displayed to the Learner 1 Track the history of the Learner in a User Model 2 Alternate the Multimedia type based on the last accessed type if (UM.history == video) then ( if (GM.Concept.label LIKE *audio*) then ( PM.GM.Concept.show = True )) else if (UM.history == audio) then ( if (GM.Concept.label LIKE *text*) then ( PM.GM.Concept.show = True )) ....
General Problems when Combining Strategies in LAG Some problems... Execution Order Variable Clashes UM.GM.Concept.beenthere += 1 Type Conflicts Strategy 1: UM.GM.Concept.accessed = True Strategy 2: if (UM.GM.Concept.accessed > 2) then (...
Why Not One Big Strategy??? Limited Reuse Difficult to Modify Complexity
Meta Strategies Meta Strategies Reuse Simplicity Modularity
A Proposed Method 1 Identify the Adaptation Behaviour Tasks 2 Identify areas where the tasks might cause problems 3 Create an adaptation strategy for each task 4 Create the controlling meta-strategy
Application to the Case Study The main tasks for the Case Study are: 1 Initialise the Course Content 2 Create a default state for the lesson being viewed 3 Show or hide content to ensure the best quality for the current network 4 Show or hide content so that only one media type is viewable based on the MediaMix rules
Problems Areas in the Case Study 1 Too much content 2 Duplicate content 3 Showing wrong content
Strategy for the Case Study - Setup Strategy initialization( while true ( if(GM.Concept.label==introduction OR GM.Concept.label==conclusion) then (PM.GM.Concept.show = True) ) ) implementation( if (GM.Concept.label LIKE *video-high*) then ( PM.GM.Concept.show = True ) else if (GM.Concept.label LIKE *text*) then ( PM.GM.Concept.show = True ) else if (GM.Concept.label LIKE *audio*) then ( PM.GM.Concept.show = True ) else if (GM.Concept.label==introduction OR GM.Concept.label==conclusion) then ( PM.GM.Concept.show = True ) else ( PM.GM.Concept.show = False ) )
Strategy for the Case Study - QoS if (GM.Concept.label LIKE *video-low*) then ( PM.GM.Concept.show = True ) else if (GM.Concept.label LIKE *video-high*) then ( PM.GM.Concept.show = False )
Strategy for the Case Study - MediaMix if (UM.history == video) then ( if (GM.Concept.label LIKE *video* OR GM.Concept.label LIKE *text*) then ( PM.GM.Concept.show = False ) else ( PM.GM.Concept.show = True ) )
Future Research Identification of Adaptation Behaviour in a Strategy Problem Detection and Resolution Automatic Creation of Output Strategies from Multiple Input Strategies
Conclusion Combining and reusing strategies can be problematic Proposed a generic method for combining strategies Further research is to investigate automating the method
Conclusion A Case Study on Merging Strategies for Authoring QoE-based Adaptive Hypermedia Joshua Scotton, Sabine Moebs, Jennifer McManis, Alexandra I. Cristea The University of Warwick and Dublin City University ݺߣs will be available from www.joshuascotton.com later today

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A Case Study on Merging Strategies for Authoring QoE-based Adaptive Hypermedia

  • 1. A Case Study on Merging Strategies for Authoring QoE-based Adaptive Hypermedia Joshua Scotton, S. Moebs, J. McManis, A. I. Cristea jscotton@dcs.warwick.ac.uk September 29th, 2009
  • 2. A Case Study Multiple Adaptation Behaviours Combining Multiple Adaptation Strategies Ease of Reuse and further Modification
  • 3. Outline Overview of the Technology General Problems with Combining Strategies A Proposed Method Application to the Case Study
  • 4. CAF + LAG Presentation Model Adaptation Model User Model Goal Model Domain Model
  • 6. Strategy for Quality of Service (QoS) Adaptation of content based on Network Conditions 1 Assess network conditions 2 Map these to a performance profile 3 Use the profile to select the content
  • 7. Strategy for Quality of Service (QoS) implementation( if(enough(PM.bandwidth_profile <= PM.loss_profile PM.bandwidth_profile <= PM.delay_profile PM.bandwidth_profile <= PM.jitter_profile,3)) then (PM.QOS = 0) else (PM.QOS = (0.5 * PM.bandwidth_profile) + (0.5*((0.4*(PM.loss_profile + PM.delay_profile)) + (0.2 * PM.jitter_profile)))) if (PM.QOS <= 0.2) then ( if (GM.Concept.label LIKE *text*) then ( PM.GM.Concept.show = True ) ) else if (PM.QOS <= 0.5) then ( if (GM.Concept.label LIKE *audio*) then ( PM.GM.Concept.show = True ) ) else if (PM.QOS <= 0.8) then ( if (GM.Concept.label LIKE *video-low*) then ( PM.GM.Concept.show = True ) ) else ( if (GM.Concept.label LIKE *video-high*) then ( PM.GM.Concept.show = True ) ) )
  • 8. Strategy for Media Mix Continual variation of Media Content displayed to the Learner 1 Track the history of the Learner in a User Model 2 Alternate the Multimedia type based on the last accessed type if (UM.history == video) then ( if (GM.Concept.label LIKE *audio*) then ( PM.GM.Concept.show = True )) else if (UM.history == audio) then ( if (GM.Concept.label LIKE *text*) then ( PM.GM.Concept.show = True )) ....
  • 9. General Problems when Combining Strategies in LAG Some problems... Execution Order Variable Clashes UM.GM.Concept.beenthere += 1 Type Conflicts Strategy 1: UM.GM.Concept.accessed = True Strategy 2: if (UM.GM.Concept.accessed > 2) then (...
  • 10. Why Not One Big Strategy??? Limited Reuse Difficult to Modify Complexity
  • 12. A Proposed Method 1 Identify the Adaptation Behaviour Tasks 2 Identify areas where the tasks might cause problems 3 Create an adaptation strategy for each task 4 Create the controlling meta-strategy
  • 13. Application to the Case Study The main tasks for the Case Study are: 1 Initialise the Course Content 2 Create a default state for the lesson being viewed 3 Show or hide content to ensure the best quality for the current network 4 Show or hide content so that only one media type is viewable based on the MediaMix rules
  • 14. Problems Areas in the Case Study 1 Too much content 2 Duplicate content 3 Showing wrong content
  • 15. Strategy for the Case Study - Setup Strategy initialization( while true ( if(GM.Concept.label==introduction OR GM.Concept.label==conclusion) then (PM.GM.Concept.show = True) ) ) implementation( if (GM.Concept.label LIKE *video-high*) then ( PM.GM.Concept.show = True ) else if (GM.Concept.label LIKE *text*) then ( PM.GM.Concept.show = True ) else if (GM.Concept.label LIKE *audio*) then ( PM.GM.Concept.show = True ) else if (GM.Concept.label==introduction OR GM.Concept.label==conclusion) then ( PM.GM.Concept.show = True ) else ( PM.GM.Concept.show = False ) )
  • 16. Strategy for the Case Study - QoS if (GM.Concept.label LIKE *video-low*) then ( PM.GM.Concept.show = True ) else if (GM.Concept.label LIKE *video-high*) then ( PM.GM.Concept.show = False )
  • 17. Strategy for the Case Study - MediaMix if (UM.history == video) then ( if (GM.Concept.label LIKE *video* OR GM.Concept.label LIKE *text*) then ( PM.GM.Concept.show = False ) else ( PM.GM.Concept.show = True ) )
  • 18. Future Research Identification of Adaptation Behaviour in a Strategy Problem Detection and Resolution Automatic Creation of Output Strategies from Multiple Input Strategies
  • 19. Conclusion Combining and reusing strategies can be problematic Proposed a generic method for combining strategies Further research is to investigate automating the method
  • 20. Conclusion A Case Study on Merging Strategies for Authoring QoE-based Adaptive Hypermedia Joshua Scotton, Sabine Moebs, Jennifer McManis, Alexandra I. Cristea The University of Warwick and Dublin City University ݺߣs will be available from www.joshuascotton.com later today