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EDUCON 2010: Adaptation in a PoEML-based E-learning Platform

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Presentation from the 2010 IEEE Engineering Education Conference

Presentation from the 2010 IEEE Engineering Education Conference

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  • 1. Adaptation in a PoEML-based E-learning Platform
    Roberto Perez-Rodriguez
    Manuel Caeiro-Rodriguez
    Luis Anido-Rifon
  • 2. Introduction
    Educational Modeling Languages (EMLs) enable the definition of UoLs in a pedagogy-independent way.
    An EML describes not only contents, but also
    Activities to perform
    Composition of groups of participants
    Order between activities
    These specifications conform a process.
    The PoEML language follows into this conceptual model, and it was developed following a separation-of-concerns approach.
  • 3. Life-cycle of a Unit-of-Learning
    Authoring: in this phase, the UoL is designed by making use of an authoring tool.
    Publication: the UoL is imported into an execution engine.
    Delivering: the participants perform the UoL. This phase is also known as run-time.
  • 4. Elements in an Educational Scenario in PoEML
  • 5. Hierarchical Educational Scenario
  • 6. Late Modeling
    A main issue in the design of e-learning systems is that of the adaptation.
    Late modeling allows for designers to leave some parts of the UoL unmodeled until run-time.
    Often, designers may prefer to model the most relevant parts of the UoL, remaining the rest to be modeled at run-time.
    Therefore, it is required to support incomplete (or abstract) models, which will be specified in run-time.
    This paper introduces a conceptual framework and a software architecture for supporting late modeling of PoEML learning-flows.
  • 7. Common Approaches to Adaptation
    Approach centered in process definition meta-model
    Advanced modeling
    Late modeling
    Approach centered in the execution system
    Type adaptation (evolutionary change)
    Instance adaptation (ad-hoc change)
  • 8. Approach Centered in Process-Definition Meta-Model
    In this approach, it is the process meta-model the one that determines the structure and the allowed types of changes. The following lines are considered:
    Advanced modeling
    Late modeling
    Advanced modeling allows authors to consider alternatives during run-time.
    The different alternatives (learning paths) that are allowed during execution are modeled in the process definition at design-time.
    During run-time, it should be possible to select one of those alternatives. There are two main ways to do the selection:
    In accordance with the state of execution.
    In accordance with the decision of an authorized participant.
  • 9. Approach Centered in the Process-Definition Meta-Model (ii)
    Late modeling allows for leaving some parts of the design without being modeled, in order to be modeled during run-time.
    Some parts of the process definition are leaved as black-boxes, in order to be modeled during execution.
  • 10. Approach Centered in the Execution System
    In this approach, it is the execution system the one that supports the types of change that are allowed.
    The following lines are considered:
    Instance adaptation
    Type adaptation
  • 11. Approach Centered in the Execution System (ii)
    Instance adaptation is usually named exception management. An exception can be seen as an occasional deviation from the normal behavior of a process. Exception management is in charge of correcting the wrong situation, without need for stopping all process instances, fix the model, and enact all the instances again.
    Type adaptation deals with process instance migration during a process execution from an old schema to a new one.
  • 12. A Late Modeling Example
  • 13. A Late Modeling Example (ii)
    The initial scenario.
    Once the initial scenario is finished, three scenarios are launched in parallel.
    Finally, participants are requested to perform a collaborative activity, which is evaluated by the teacher.
  • 14. A Late Modeling Example (iii)
    Order and Temporal views of scenarios
    The teacher may want to tune the model in some ways:
    Adding more activities.
    Changing the temporal constraints for activity finishing.
    Adding/skipping a goal, etc.
  • 15. Late Modeling of PoEML Learning-Flows
    Following an aspect-oriented approach, the allowed changes in the model can be systematically categorized in aspects, each one dealing with an specific concern.
    A. Situating placeholders in the UoL model
    The approach here is to use a special type of construct, named placeholder.
    The placeholder occupies the place of the unmodeled element or specification.
  • 16. Late Modeling of PoEML Learning-Flows
    A. Situating placeholders in the UoL model.
    In PoEML, we identify the following placeholder types:
    Scenario placeholder. It is a black box that reserves space for a scenario model. The language constructs will be added at run-time in the space kept by the placeholder.
    Goal placeholder. It reserves the space for the definition of a learning objective.
    Environment placeholder
    Tool placeholder
    Data placeholder. It is used for reserving the space to add resources and/or activities to a UoL at run-time.
    Order placeholder. It keeps the space for adding ordering constraints at run-time.
    Temporal placeholder. It enables the deferred definition of temporal constraints in the Unit of Learning.
  • 17. Late Modeling of PoEML Learning-Flows
    B. Modeling black-boxes at run-time
    When the execution flow reaches a black-box, the educational scenario is instantiated, but it cannot progress towards the accessible state.
  • 18. Late Modeling of PoEML Learning-Flows
    A learning-flow with a temporal placeholder in the final scenario.
    At run-time the teacher may fill the placeholder by making use of the authoring environment.
  • 19. Late Modeling of PoEML Learning-Flows
    C. Updating of instances.
    Every learner who starts a learning-flow enacts a new instance.
    Every learning-flow instance has its own state.
    When a teacher commits a change in the learning-flow model, every instance has to be re-evaluated from root to leaves in order to update its state.
  • 20. The Moodle Extension for PoEML
    A. The authoring environment
    The authoring process consists on a series of atomic operations.
    Add/edit/delete a scenario
    Add/edit/delete a goal
    Add/edit/delete a resource/activity
    This authoring strategy presents some advantages
    Atomic changes are automatically seen by other co-authors
    There is no need for a complex consistency check like the one needed when importing a manifest file
  • 21. The Moodle Extension for PoEML (ii)
    B. The run-time environment
  • 22. The Moodle Extension for PoEML
    C. Monitoring
    Monitoring of a goal
    Possible states of a goal and number of students per state. Histogram
    Detail of the status of a goal for every enrolled student
  • 23. Implementation
    Overall architecture
  • 24. Implementation
    A. The learning-flow engine
    It is the core component of the e-learning system
    Stores information on scenarios, participants, goals, etc. and it makes the state of the system to evolute depending on events
    This component is integrated through a well-defined interface
    Two subcomponents:
    Models manager
    Instances manager
  • 25. Implementation
    B. The middleware layer
    The functionality of the learning-flow engine is published into a WSDL file.
    C. Presentation modules
    Three views:
    Authoring
    Monitoring
    Delivering
  • 26. Conclusions
    This paper details the implementation of a late modeling approach for PoEML
    Late modeling allows for leaving some parts of a UoL model unspecified until run-time
    The aspect-orientation of PoEML presents great advantages in supporting late modeling
    The combination of late modeling and advanced modeling provides a high degree of adaptation
    Future work: to support adaptation based on the execution engine
    Instance adaptation
    Type adaptation