- http://gnosis.dschool.edu.gr/decks/2014-05-06_Photodentro-Aggregator-Arch/ - https://speakerdeck.com/tafkey/the-photodentro-aggregator-federated-system-architecture Presented at the 11th EdReNe Conference (Athens, May 6th, 2014)

1. THE PHOTODENTRO AGGREGATOR FEDERATED
SYSTEM ARCHITECTURE
A POWERFUL METADATA AGGREGATOR BACKEND, COUPLED WITH A WEB PORTAL FRONTEND
FOR A MOBILE-FRIENDLY, ACCESSIBLE AND SOCIALLY INTERACTIVE USER EXPERIENCE.
Anastasios Koutoumanos Ph.D.
Computer Technology Insitute & Press - Diophantus
koutoumanos@cti.gr
,May6th2014,Athens,Greece11thEdReNeConference

2. OUR TEAM
A'digital' team for implementing and supporting
the 'digitalservices' of the digitalschool!
Headed byProf.Christos Kaklamanis
Coordinated byDrElina Megalou
An efficientsoftwareteam
11 full-time, in-house developers &dev-ops
a team of ~10 externalcolleagues doing part-time work
Agreatback-officeteamfor supporting our work, the digital
services and the associated content

3. THE CONTEXT: PHOTODENTRO IS THE ...
Greek NationalAggregator of EducationalContentfor schools.
Ithas been designed and developed in the frameworkof the
"Digital School" National Initiative of the GreekMoE

4. PHOTODENTRO AGGREGATOR
Amulti-layer and service oriented architecturehas been used
for the PhotodentroAggregator, with the following layers:
1. the Ingestionlayer, thatprocesses metadata from various
externalsources,
2. the CollectionManagement Layer, thatmanages the
collections thatare to be aggregated in the Federation and
provides an environmentfor their metadata enrichment,
3. the AggregationLayer, where the metadata harvesting,
validation, and storing take place, and
4. the PhotodentroWebportal, thatprovides generalservices
to portalusers as wellas access to the resources of various
repositories in a uniform way.

5. 1

6. SYSTEM ARCHITECTURE
THE MAIN COMPONENTS
Sources of related material
Repositories with learning resources
Photodentro instances
Other, compliantrepositories
The Photodentroaggregator
The Photodentroportal

7. PHOTODENTRO AGGREGATOR
THE MAIN COMPONENTS
DSpace Aggregator engine Portal frontend
LOM APbuilder
Unique Identifier service
OAI-PMH target
Support services
Vocabulary server
LOM Validator
OAI-PMH Harvester
Quality Controlengine
Link check
Photodentro LOM APvalidation
Schedule management (cron)
Reporting
SOLRIndexing
Transformation
Publish
Layout
SocialFeatures

8. INJESTION & COLLECTION
MANAGEMENT

9. METADATA INJESTION & TRANSFORMATION
Photodentro uses the MINT tool (partof the
) for gathering metadata from external
repositories as wellas for facilitating the metadata mapping
process.
Metadata
InteroperabilityServices

10. COLLECTION MANAGEMENT
Three differentcases of repositories:
Case1:Fullsupport
Fullysupportthe Photodentro IEEE LOM AP, and
Provide an OAI-PMHtarget, and
there is no need for metadata enrichment
Case2:DifferentIEEE LOM APor other standard (e.g. LIDO)
Case3:Partialsupport
Fullysupportthe Photodentro IEEE LOM APand
Provide an OAI-PMHtarget, but
metadata enrichmentis needed

11. METADATA PREPARATION
A(heavilycustomised version of) DSpaceis used to provide:
a UniqueIdentifierservice
mapping to the PhotodentroLOM ApplicationProfile
an OAI-PMH target
TheHANDLEsystemisusedasthebackendservice
to creategloballyunique,persistent andindependent identifiers.

12. AGGREGATOR REQUIREMENTS
collectmetadata records from the Photodentro ecosystem
enforce qualityand unique identifiers
prepare metadata to be used bythe Photodentro portal
link metadata againstthe taxonomies and terms of the
VocabularyBank
facilitate smartindexing and advanced queryservices
(Athena)
facilitate association of metadata with related socialdata and
analytics

13. OUR APPROACH: DRUPAL BASED
The main workflow
1. An OAI-PMHmodule is used as and aggregatorto harvestall
connected repositories.
2. Asetof curationtasks are performed
3. Each valid metadata record is tranformed to a Drupal entity
4. Each entityis submitted to the SOLR indexer
5. Drupalentities enter the normalpublishing workflow

15. ACTION PLEASE!

32. HANDS ON. LIVE!
Note: This is only for demostration purposes. Systemunder heavy
development!

33. WEB SERVICES & TOOLS
VocabularyBank
Photodentro OAI-PMHtarget(DSpace)
Photodentro portal(Drupal)
Human view
Web services
Photodentro LOR
Photodentro Video
Frontend
Backend

34. PLANNING...
... AND THE FUTURE

35. PLANNING
The system is currentlyunder development
1stworking version is expected by September 2014
Potentialuser base:approx. 1.5 milion, mostlymembers of the
Greek K-12 community.
Everyone willbe motivated to registeras a member
Emphasis on community-orientedfeatures
Responsive,finger-friendly user interface
Facetedsearch, intuitivesearchmechanism
Accessibilityis facilitated (WCAG 2.0 LevelAA) and expanded
with speech-enabledwebcomponents
Architectured for scalability

36. THE FUTURE
Integration of the Photodentro aggregator and portalto the
other dschoolcomponents.
Explore the micro-sites paradigm
Managementof socialdata &paradata, processing of
analytics
Further supportthe Linked-Data paradigm
Link to more repositories, both inbound and outbound
... more to come. We listen to our users!