08 learning object repository with cordra


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08 learning object repository with cordra

  1. 1. Learning Object Repository and CORDRA Timothy K. Shih
  2. 2. Outline • Concept of Repository • Two Models • Real Cases • The CORDRA Framework – MINE SCORM Repository
  3. 3. E-Learning Functionality by Type of Tools Authoring ToolsLMSs Store Content Gather Content (push/pull using meta-data & federated searches) Publish Content (provide meta-data to other repositories) Repackage Content Export Content Import Content •Student Enrollment •Course Enrollment •Designate Instructors & Assign Instructor Rights & Roles •Match Students with Instructors •Monitor/Track Student/Learner Performance •Sequence Content Presentation •Create & Associate Meta-data •Create Content •Package Content Repositories
  4. 4. Advanced Distributed Repository Network • A REPOSITORY – holds information and objects to meet learning design objectives – a system providing storage for electronic learning objects and their own metadata
  5. 5. CORDRA -- ADL's Federated Content Repository Model • A reference model – Collection of existing standards • An “identifier” system • An overall “architecture” • Operational community implementations – Independent existing repositories – CORDRA instance – Instance and repository specific operational rules and policies
  6. 6. ADL’s Problem: Finding Content • SCORM specifies how to develop and deploy content objects that can be shared and contextualized to suit the needs of the learner • SCORM provides the means to tag content for later discovery and access in a distributed environment BUT: • SCORM is silent about how discovery and access are to be implemented
  7. 7. ADL’s Motivation: DoDI 1322.20 • US DoD learning content must conform to SCORM • Content must be placed in an accessible, searchable repository • Before developing new content, search repositories for reusable, repurposable content
  8. 8. Overall CORDRA Model
  9. 9. Overall CORDRA Model • Collection of local content repositories • Implementation-specific system repositories – Master catalog (content registry) – Repository registry – System registry • Common Services Infrastructure • Identifier System • Applications
  10. 10. Key CORDRA Operations • Register a content object in the Content Catalog for later search and retrieval • Search the Content Catalog; it returns content objects (via their IDs) and metadata • Register a content repository in the Repository Registry by specifying local data and rules • Query the Repository Registry for the operational, policy and business rules
  11. 11. Content Object Creation Create Content Assign ID100.xyz/cp Publish in Repository Source: Daniel R. Rehak, “CORDRA: ADL's Federated Content Repository Model”, Presented at 16th Annual Instructional Technology Institute at Utah State University (20040902, Logan, UT)
  12. 12. Content Object Registration 100.xyz/cp Identify Content in Repository for Registration Get Content ID Register Content Extract Metadata Deposit Metadata
  13. 13. Content Object Search Enter Search CriteriaSearch Catalog 100.abc/cp1 100.abc/cp2 100.xyz/cp 100.qrs/cp Return Content IDs Select Content 100.xyz/cp
  14. 14. Content Object Access 100.xyz/cp Identify Content Resolve Identifier Determine Repository and Access MethodsAccess Content in Identified Repository Retrieve Content 100.xyz/cp
  15. 15. Repository Registration Create Repository Metadata Assign ID 100.reg/rep Register
  16. 16. Repository Query Enter Search CriteriaSearch Catalog Obtain Repository Metadata
  17. 17. Local Content Repositories • Persistent stores of content • Defined service interfaces to integrate with CORDRA • Registered as part of a CORDRA implementation • Operated and maintained independently of CORDRA
  18. 18. System Repositories • Master Catalog – Content Registry – Metadata storage – Used for all search and access • Repository Registry – Descriptions of all repositories • System Registry – Descriptions of the CORDRA model and its implementation  All registered in the repository registry
  19. 19. Identifier Infrastructure • Uses the Handle System – Persistent, unique identifiers (names) – Resolution of name conflicts • Local namespaces for each implementation • Common CORDRA namespace for system components
  20. 20. Handle System • A comprehensive system for assigning, managing, and resolving persistent identifiers, • Known as "handles,“ • By CNRI, IETF RFC 3650~3652 2096/windslash Naming Authority prefix Local Name suffix
  21. 21. • Significant role in the evolution of network infrastructure –Technological –Organizational • Current work in digital object architecture –Identifying and managing content objects Why is CNRI Involved
  22. 22. Applications • Built upon CORDRA infrastructure (repositories, IDs, common services) • Service-oriented model with user interfaces and agents – Content search – Content registration – Content harvest – Repository registration – Content delivery – Content assembly and customization – …
  23. 23. Federated CORDRA • A collection of CORDRA community implementations • A single level of federation – Registry of CORDRA registries • CORDRA system objects and registry independent of any individual implementation
  24. 24. CORDRA Summary • A reference model – Collection of existing standards • An “identifier” system • An overall “architecture” • Operational community implementations – Independent existing repositories – Community CORDRA instance – Instance- and repository-specific operational rules and policies
  25. 25. MINE SCORM Repository A Partner of the Academic ADL Co-Lab
  26. 26. Repositories • SCORM Provides – Content Packaging – Metadata – Run-Time Environment • What bout Discovery & Access? – Content Registration (name space) – Common Catalog – Repository Infrastructure – Federated Repository Discovery DeliveryContext Identification Location Resolution Retrieval The CORDRA “Triangle”
  27. 27. CORDRA a model for a global content infrastructure • Content Object Repository Discovery and Registration/Resolution Architecture • An open, standards-based model for how to design and implement software systems for the purposes of discovery, sharing and reuse of learning content through the establishment of interoperable federations of learning content repositories
  28. 28. CORDRA Team ADL CNRI LSAL technology digital object architecture identifiers requirements ADL-R deployment architecture prototype research coordination best practices standards user community architecture CORDRA governance outreach tools registries prototypes deployment documents
  29. 29. ADL, CORDRA & SCORM ADL Registry CORDRA Instructional Capability, Modeling & Simulation, Intelligent Tutoring, Economic Models, Policy, R&D, etc. CORDRA Instance Technical Specifications
  30. 30. Key CORDRA Operations • Register a content object in the content catalog for later search & retrieval • Search the content catalog; return content objects (via their IDs) & metadata • Register a content repository in the repository registry by specifying descriptive data & rules • Query the repository registry for the operational, policy & business rules
  31. 31. Federated CORDRA: global infrastructure • A collection of CORDRA community implementations • A single level of federation – registry of CORDRA registries • CORDRA system objects & system registry independent of any individual implementation
  32. 32. The ADL Registry – An Instance of CORDRA • Technological and Organizational Infrastructure – Register the existence and access conditions for Learning Objects relevant to the DoD „Enterprise‟ – Provide user interface to search the registry • Integrates existing technologies – Handle System for identification and access – XML for object description and submission – LOM metadata – Repository for metadata object storage and access – Lucene search engine • Running at CNRI in pilot phase
  33. 33. How to Register Content in ADL-R • Create a Registry Transaction (REG-T) – Define the registering User and Group – Set the operation to be an “Insert” – Define the Content Object – Define the Content Object Location and Type – Define the Content Object Metadata – Define the Metadata Handle and Schema • Submit the REG-T • Get the Transaction ID of the REG-T • Check the Transaction Status (REG-TS)
  34. 34. Submit the REG-T http://www.adlnet.org/
  35. 35. Check the Status • Submit the Transaction ID to get the Transaction Status (REG-TS). http://www.adlnet.org/
  36. 36. Search • To Search for the Content, add Metadata http://www.adlnet.org/
  37. 37. Search Result http://www.adlnet.org/
  38. 38. For More Information • http://lsal.org/ • http://cordra.net/ • hdl:2000/1 • lsal@lsal.org • cordra@cordra.net
  39. 39. Object Orientation Issues in SCORM and CORDRA • SCORM defines metadata for learning objects • CORDRA • Reusability – Search for and make copy of a learning object (LO) – Modify part of the learning object – Are the new and the original objects related? • Search – Should the association among LOs be retrieved? – Progressive Search?
  40. 40. Motivation • Revision Control –Reusability Tree • Guided Search –Progressive Search Specification
  41. 41. Object Orientation • New LO created (copied) may inherit properties from its original • Inheritances – Actual Contents – Structure • S&N rules • Reusability Tree – For LOs – Evolution of Changes Learning Object O Learning Object A (change structure) Learning Object B (change S&N) Learning Object C (change content) Learning Object E Learning Object F Learning Object D Learning Object G (structure from D contents from F)
  42. 42. Inheritance • Contents • Metadata – Fundamental properties • Title, Copyright, Language, Requirement, etc – Changing properties • Keywords, Version, Status, Min/Max Version, etc • Template of structure (Content Aggregation) – S&N rules
  43. 43. Examples of Inheritance Learning Object O Learning Object A (change structure) Learning Object C (change content) Learning Object E (change platform) Learning Object D (change language) A is re-organized based on contents of O C adds additional contents from O D is translated based on contents from A E requires a new version of browser
  44. 44. Multiple Inheritance • One learning object inherits properties from more than one learning objects • Example – G Inherit structure from learning object D – G Inherit SCOs (and metadata) from F • Example – Combining two SCOs Learning Object FLearning Object D Learning Object G (structure from D contents from F)
  45. 45. Revise the Concept of Search • Knowledge Encapsulation – Metadata encapsulates details of contents • Finds a learning object and its instances (children) in a reusability tree • Progressive Search (Constraint Reasoning) – Precision ratio and recall ratio • Rewritable Metadata Template as search specification • Goal: Deduction of Search Specification – Based on User Relevance Feedback – System Guides Progressive Search Criteria
  46. 46. Search Criteria – Analysis of LOM • Precise Criteria: 6 items, items that must be precisely described – (e.g., Title = “Photoshop Tutorial”, Language = “en”). • Incremental Criteria: 10 items, items that can be revised to constrain a search specification – (e.g., Keyword = “Tamkang University”, Keyword = “Tamkang University AND MINE Lab”, Keyword = “Tamkang University AND MINE Lab AND Freya Lin”). • Precedence Criteria: 5 items, the items can be evaluated with a operator such as <, <=, >, >=, = and != – (e.g., Size >= 1024, Interactivity Level > medium, Semantic Density <= low).
  47. 47. Search Criteria – Analysis of LOM • Time/Duration Criteria: 5 items, time items that can be searched with a operator such as <, <=, >, >=, = and != – (e.g., Date > 2006-03-20, Duration <= PT1H30M). • Single Choice Criteria: 21 items, only one vocabulary can be chosen for the item – (e.g., Aggregation Level = sco, Minimum Version = 5.0). • Many Choice Criteria (disjunction): 7 items, multiple vocabularies can be chosen for the item – (e.g., Intended End User Role = teacher OR author, Purpose = idea OR discipline).
  48. 48. Metadata Template • Search specification can be revised • Mandatory searching criteria – Minimal set, to ensure recall ratio – e.g., Keyword • Progressive searching criteria – Sufficient set, dynamically added, to ensure precision ratio – e.g., Title, Min/Max Version • How to upload? How to search? How to Revise CORDRA?
  49. 49. CORDRA – Revised • Reusability Tree is a distributed concept • Centralized vs. decentralized • Replication of learning objects – Should the handler system know this? • Where and how to store the reusability tree? – Master Content Catalog Learning Object O Learning Object A (change structure) Learning Object B (change S&N) Learning Object C (change content) Learning Object E Learning Object F Learning Object D Learning Object G
  50. 50. MINE Registry • An instance of CORDRA • Maintaining reusability tree • Will be integrated with an authoring tool • Register a New/Inherited Learning Object • Discover and Reuse Learning Objects
  51. 51. Register 1. upload learning object 2. extracts metadata 3. generate handle (for new and inherited object) 4. return handle OID and handle MIDs 5. association between OID and MID 6. stores multimedia files and metadata 7. create/update reusability tree 8. update URL of Content Server to associate with handle 6 6’ 2 1 3 8 Local Handle Service Clients Content Server Content Object Registry Master Content Catalog 4 5 7 6 content 6’ metadata 2 metadata 1 LO 3 req. 8 URL Local Handle Service Clients Content Server Content Object Registry Master Content Catalog 4 handle 5 OID –MID 7 RTOID – MID Reusability Tree MID, metadata Handle – URL Master Content Catalog maintains a centralized control of reusability tree.
  52. 52. Discover 1. sends search criteria 2. finds matched MIDs and its corresponding reusability tree 3. finds OIDs for MIDs 4. passed OIDs (or reusability tree) and MIDs 5. selects learning objects by OIDs (or reusability tree) 6. find the Local Handle Service 7. finds physical URLs 8. downloads the physical multimedia files 2 criteria MID1 criteria 3 MID OID 5 OID 7 URL 4 OID – MID Clients Learning Object Search Engine Content Object Registry Global Handle Proxy Server Local Handle Service Content Server Master Content Catalog 6 Handle ID 8 content OID – MID Handle – URL Reusability Tree MID, metadata
  53. 53. Implementation of MINE Registry
  54. 54. Demonstration of MINE Registry Video Clip Available at http://www.mine.tku.edu.tw/SCORM/
  55. 55. Open Architecture for Learning Object Rediscovery III SCORM Authoring Tool ADL SCORM Authoring Tool Search Specification Signature of Authorized Contents Open Repository Interface DRM Federated Search Engine ADL Registry MINE Registry III Registry MINE SCORM Authoring Tool
  56. 56. Summary • CORDRA – Revised – Reusability Tree – Rewritable search specification (template) – Guided search (with user relevance feedback) • High Level Search Specification – For general users – Generation of search specification • The MINE Registry is only a draft implemented – Need to integrate with authoring tool – Need to test with other CORDRA instances