Transcript PlanetDR, a scalable architecture for federated

PlanetDR, a scalable architecture for federated
repositories supporting IMS Learning Design
Josep Blat, David Griffiths, Toni Navarrete, José
Luis Santos, Pedro García, Jordi Pujol
Paper presentation, TENCompetence workshop,
Sofia, March 31st 2006
The problem (1)
1 Islands of resources
– Many specifications have been proposed
for distributed content repositories, e.g.
• Ariadne
• Edutella
• Pond
– Lack of interoperability leads to content
islands exist of tagged LOM contents only
available to small groups
Problem (2 & 3)
2 The use of zip files replicated locally (as
in Content Packaging) runs counter to
trends to dymanically updated remote
resources and web services
3 Integration with users’ workflows is poor
Problem 1. Islands of
resources
• IMS Digital Repository Interoperability (DRI)
is intended to enable server interoperability
• Provides functional architecture and
reference model.
• Aims at very broad recommendations, and
resolution of operational issues is left to
developers.
• This leaves many open questions about
implementation and effectiveness
PlanetDR ECL support
• Edusource Communication Lanaguage (ECL)
is a concrete instance of DRI
• Planet is a Spanish nationally funded project.
• PlanteDR the first Open Source repository
which fully implements LOM, DRI and ECL
• Intended for very large federated educational
digital repositories
Federation
• Edusource content servers are standalone
and “unaware” of other content servers in the
eduSource network
• They are linked together by hand at a central
location.
• This limits scalablilty
• PlanetDR has a federation mode which
supports plug & play decentralized
management of PlanetDR compatible
servers,
Problem 2: zip files v. web
services (1)
• Content Packaging is closer to the world
of CD Roms than to web services,.
• Difficult to make full use of distributed
resources, continually updated
• Imposes downloading, re-packaging.
• More natural perspective in the context
of the Web is to link directly to the
(distributed) resource(s).
Problem 2: zip files v. web
services (2)
• The work done in UNFOLD and now in
TENCompetence is important for
squaring this circle.
• PlanetDR makes a contribution in this
direction
PlanetDR services
• Planet web services include
– search
– submit
– Request
• Through ECL, can invoke any web
services from other content servers in
the eduSource network.
Problem 3. Workflow support
for Learning Designers
• PlanetDR, like other repostiories, supports
search and retrieval of resources based on
LOM as an isolated task,
• A much more natural working context is to
perform this task when an author is designing
a UoL, and to be able to include the
resources retrieved in the UoL.
Integration with Reload
• The Reload editor has been extended to
allow to search and retrieve resources from
the PlanetDR repository, and include them in
the workflow of UoL production.
• New window added to Reload where the user
specifies the fields for searching the
resources in the repository
– Name
– Keywords
– format.
Integration with Reload (2)
• The tool builds an XQuery statement,
which is sent to the repository and
executed.
• Results returned, and user selects
resources for download as a content
package
• This uses the search and request web
services of the PlanetDR repository
More information and
downloads
• http://planet.urv.es/planetdr/
• [email protected]
• New release will shortly be available