08 learning object repository with cordra

Learning Object Repository and CORDRA

Timothy K. Shih

Outline

• Concept of Repository• Two Models• Real Cases• The CORDRA Framework

– MINE SCORM Repository

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

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

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

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

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

Overall CORDRA Model

Common Services/ Infrastructure

RepositoryRegistry

MasterCatalog

Repository

FileServer

MediaServer

LHS

SystemRegistry

Repository Repository

ContentServer

ContentServer

CatalogServer

ContentServer

Identifier System

Applications

LHS/RA LHS

GHS

LHS/RA

DRM

Authentication

Application Server

Search

ApplicationServer

Harvest

ApplicationServer

Register

ApplicationServer

Customize& Deliver

Local Content RepositoriesSystem Repositories

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

Common Services/ Infrastructure

RepositoryRegistry

MasterCatalog

Repository

FileServer

MediaServer

LHS

SystemRegistry

Repository Repository

ContentServer

ContentServer

CatalogServer

ContentServer

Identifier System

Applications

LHS/RA LHS

GHS

LHS/RA

DRM

Authentication

Application Server

Search

ApplicationServer

Harvest

ApplicationServer

Register

ApplicationServer

Customize& Deliver

Local Content RepositoriesSystem Repositories

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

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)

Content Object Registration

100.xyz/cp

Identify Content in Repository for RegistrationGet Content ID

Register Content

Extract Metadata

Deposit Metadata

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

Content Object Access

100.xyz/cp

Identify Content

Resolve IdentifierDetermine Repository and Access MethodsAccess Content in Identified RepositoryRetrieve Content

100.xyz/cp

Repository Registration

Create Repository Metadata

Assign ID

100.reg/rep

Register

Repository Query

Enter Search CriteriaSearch Catalog

Obtain Repository Metadata

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

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

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

Handle System

• A comprehensive system for assigning, managing, and resolving persistent identifiers,

• Known as "handles,“

• By CNRI, IETF RFC 3650~3652

2096/windslash

Naming Authorityprefix

Local Namesuffix

• 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

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– …

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

CORDRARegistry

CORDRARegistry

ContentRepository

ContentRepository

ContentRepository

ContentRepository

ContentRepository

ContentRepository CORDRA

Registry

ContentRepository

ContentRepository

ContentRepository

ContentRepository

CORDRARegistry

FederationRepository

FederationCatalog

FederationRegistry

CORDRA Implementation




FederatedCORDRA

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

MINE SCORM Repository

A Partner of the Academic ADL Co-Lab

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 LocationResolution

Retrieval

The CORDRA “Triangle”

CORDRAa 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

CORDRA Team

ADL

CNRI

LSAL

technology

digital object architecture

identifiers

requirements

ADL-R deployment

architecture

prototype

research

coordination

best practices

standards

user community

architecture

CORDRAgovernance

outreachtools

registries

prototypes

deployment

documents

ADL, CORDRA & SCORM

ADLRegistry

CORDRA

Instructional Capability, Modeling & Simulation, Intelligent Tutoring, Economic Models, Policy, R&D, etc.

CORDRA Instance

TechnicalSpecifications

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

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

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

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)

Submit the REG-T

http://www.adlnet.org/

Check the Status

• Submit the Transaction ID to get the Transaction Status (REG-TS).


Search

• To Search for the Content, add Metadata


Search Result


For More Information

• http://lsal.org/• http://cordra.net/• hdl:2000/1• [email protected]• [email protected]

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?

Motivation

• Revision Control–Reusability Tree

• Guided Search–Progressive Search Specification

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

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

Examples of Inheritance

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

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 Dcontents from F)

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

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).

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).

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?

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

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

Register

1. upload learning object

2. extracts metadata3. 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

6content

6’metadata

2metadata

1LO

3req.

8URL

Local Handle Service

Clients

Content Server

Content Object Registry


4handle

5OID –MID

7RTOID – MID

Reusability TreeMID, metadata

Handle – URL

Master Content Catalog maintains a centralized control of reusability tree.

Discover

1. sends search criteria 2. finds matched MIDs

and its corresponding reusability tree

3. finds OIDs for MIDs4. 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 URLs8. downloads the physical

multimedia files

2criteriaMID1

criteria

3MIDOID

5OID

7URL

4OID – MID

Clients

Learning Object Search Engine Content Object

Registry

Global Handle Proxy Server Local Handle

Service

Content Server


6Handle ID

8content

OID – MID

Handle – URL

Reusability TreeMID, metadata

Implementation of MINE Registry

Demonstration of MINE RegistryVideo Clip Available at http://www.mine.tku.edu.tw/SCORM/

http://www.mine.tku.edu.tw/SCORM/

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

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