An ADL Framework for Learning Content Contextualization, Discovery,and Resolution

1
An ADL Framework for LearningContent
Contextualization,Discovery,and Resolution

• Philip V.W. Dodds
• ADL Chief Architect
• Paul Jesukiewicz
• Director, ADL Co-Laboratory
• J. D. Fletcher
• Institute for Defense Analyses
• June 2004

2
The Problem Space

• The SCORM framework 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 is
  to be implemented

3
A New Framework

• Content Object Repository
• Discovery and Registration/Resolution
  Architecture
• CORDRA

4
ADLs Approach

• Articulate the high level requirements, policies
  and business rules for instructional content
  repositories that constrain the architecture such
  that it can be implemented consistently.
• Identify and relate the most relevant
  technologies and specifications that can be
  applied to the architecture (connect the dots).
• Define a framework on which a number of services
  may be built (but without defining the
  implementation of such services).
• Provide a model that can scale.

5
Assumptions Unique To ADLs Community

• Assumption 1 Developers of learning content want
  their content to be found.
• Requirement A means for discovering where
  content is available
• Assumption 2 Most users and developers are not
  skilled at either tagging content or expressing
  detailed queries.
• Requirement Guidance and very simple interfaces
  for tagging content are needed.
• Assumption 3 Searchers of content have specific
  criteria in mind.
• Requirement A means to relate search criteria
  based on context to descriptions of specific
  content objects (e.g., mapping a skill definition
  to an object that addresses that skill).
• Assumption 4 Searchers of content often want
  only exactly what they need.
• Requirement A means to insure that discovered
  content is relevant, accredited and authorized
  (among other properties) is required to assure
  the delivery of appropriate content.

6
Assumptions (continued)

• Assumption 5 Forcing a rigid information,
  service and protocol model wont scale.
• Requirement An approach is required that is low
  cost and easy to implement and that allows
  voluntary support and adoption, and minimal
  alteration of existing approaches.
• Assumption 6 The architecture must enable local
  policies and business rules, not define them.
• Requirement The means to institute and expose
  local business rules and policies so they may be
  used or mapped to and from other systems.
• Assumption 7 We cannot foresee all of the
  services or capabilities that will eventually be
  required.
• Requirement An architecture is needed that will
  enable new services and capabilities to be added
  without changing the underlying structure.

7
Discovery

• Two extremes of discovery
• Exact and/or thorough (e.g., library collection
  searching)
• Whats out there that might related (e.g.,
  Google)
• Preferred Process
• Develop search criteria
• Go to a master index of relevant repositories
• Go to the appropriate repository
• Discover what it has that is relevant
• This suggests the value of a registry of
  repositories that want to be found

8
CORDRA Triangle
9
Resolution

• Identification of an object and knowing where it
  is are different things
• The Handle System may help us
• The Handle System has been designed from the
  start to serve as a general-purpose naming
  service. It is designed to accommodate very large
  numbers of entities and to allow distributed
  administration over the public Internet. The
  Handle System data model allows access control to
  be defined at the level of each of the data
  values associated with a given handle. Each
  handle can further define its own set of
  administrators that are independent from the
  network or host administrator.
• -- from IETF RFC 3650

10
The Handle System
Handles are Persistent and Globally Unique
11
The Handle System - Resolution
Global Handle Registry CNRI
100.navy.navair/100344jjp Resolves to
(returns) http//navair.pax.mil/training/object23
.zip
Local Naming Authorities
DTIC 100.
IDF -DOI 10.
Library Of Congress loc.
CMU
100.army
100.navy
100.Airforce
Handle policies Community of practice
12
ADL CORDRA Proposed Framework
Global Handle Server _at_CNRI
Marines
Joint
Navy
Air Force
Army
Distributed Repositories
13
Registering a Content Object
Global Handle Server _at_CNRI
1. Create Content (obtain handle optionally)
e.g., 100.navy.navair/1002184jr
3. Register object by obtaining (or updating) a
handle record and sending the objects location
and search metadata
Marines
2. Publish object by placing it in a repository
Joint
Navy
Air Force
Army
Distributed Repositories
14
Registering a Repository
Global Handle Server _at_CNRI
2. Register repository location by obtaining a
handle for it and sending its metadata to the
registry (probably a web form transaction)
Marines
Joint
1. Create Repositorys metadata (location, access
procedures, authority, search services, etc.)
Navy
Air Force
Army
Distributed Repositories
15
Searching For An Object
1. Access search service and enter search metadata
Global Handle Server _at_CNRI
2. Service searches object index
3. Service identifies and returns handles for
hits
Object Search Service
Marines
Joint
Navy
Air Force
Army
Distributed Repositories
16
Retrieving An Object
1. Client (you) sends a handle query to the
Handle System. The query is sent to the
appropriate local Handle Server.
Global Handle Server _at_CNRI
2. Local Handle System looks up (resolves) the
handle and returns the location of the object
Registry contains the location information for
the object
3. Client directly requests the object from the
location provided by the handle service.
Marines
get request
Joint
Navy
Air Force
Army
Distributed Repositories
17
Searching For Repositories
1. Access search service and enter search
criteria (e.g., show me all repositories or tell
me about this one) service returns results.
Global Handle Server _at_CNRI
Repository Search Service
Marines
Joint
Navy
Air Force
Army
Distributed Repositories
18
Locating A Specific Repository
1. Access search service and request the handle
of the desired repository service returns
handle.
2. Client (you) sends a handle query for the
repository to the Handle System. The query is
sent to the appropriate local Handle Server which
then returns the location of the repository.
Global Handle Server _at_CNRI
Repository Search Service
Registry contains the location information for
the repository
3. Client directly accesses the repository
through location provided by the handle service.
access request
Joint
Navy
Marines
Air Force
Army
Distributed Repositories
19
Enabling Services

• We need lots of services
• Policy enforcement
• Resolution/retrieval
• Authentication, authorization and auditing
• Digital rights management
• Security
• Processing community specific business rules
• Smart search/discovery
• many others

20
ADL CORDRA Proposed Framework
Global Handle Server _at_CNRI
Resolution System
Marines
Identifier System
Joint
Navy
Air Force
Army
Distributed Repositories
21
Conclusion

• DoD (OSD PR) expects to stand up a test version
  by early fall
• CNRI is creating the initial code instance
• Test bed to go operational at DTIC early CY 05
• OSD will issue a DoD Instruction requiring that
  learning content and repositories be registered
  in this system
• Other instances of CORDRA could be applied to
  other domains
• Eventually a Registry of CORDRA Instances is
  envisioned

22
Thank you!

• pdodds_at_rhassociates.com