EDUTELLA: a P2P networking infrastructure based on RDF

Publication Type: 
Conference Paper
Authors: 
Wolfgang Nejdl
Tore Risch
Boris Wolf
Changtao Qu
Stefan Decker
Michael Sintek
Ambjorn Naeve
Mikael Nilsson
Matthias Palm
Journal: 
WWW '02: Proceedings of the 11th international conference on World Wide Web
Publisher: 
ACM Press
Pages: 
604-615
Year: 
2 002
Place Published: 
New York, NY, USA
ISBN: 
1-58113-449-5
Keywords: 
peer-to-peer
URL: 
http://cid.nada.kth.se/pdf/CID-205.pdf
Abstract: 
Metadata for the World Wide Web is important, but metadata for Peer-to-Peer (P2P) networks is absolutely crucial. In this paper we discuss the open source project Edutella which builds upon metadata standards defined for the WWWand aims to provide an RDFbased metadata infrastructure for P2P applications, building on the recently announced JXTA Framework. We describe the goals and main services this infrastructure will provide and the architecture to connect Edutella Peers based on exchange of RDF metadata. As the query service is one of the core services of Edutella, upon which other services are built, we specify in detail the Edutella Common Data Model (ECDM) as basis for the Edutella query exchange language (RDF-QEL-i) and format implementing distributed queries over the Edutella network. Finally, we shortly discuss registration and mediation services, and introduce the prototype and application scenario for our current Edutella aware peers.
Notes: 

P2P applications have been successful for special cases like exchanging music files. However, retrieving "all recent songs by Madonna" does not need complex query languages nor complex metadata, so special purpose formats for these P2P applications have been sufficient. In other scenarios, like exchanging educational resources, queries are more complex, and have to build upon standards like IEEE-LOM/IMS metadata with up to 100 metadata entries, which might even be complemented by domain specific extensions.
The Edutella project addresses these shortcomings of current P2P applications by building on the W3C metadata standard RDF. The project is a multi-staged effort to scope, specify, architect and implement an RDF-based metadata infrastructure for P2P-networks based on the recently announced JXTA framework.
The initial Edutella services will be:

- Query Service: standardized query and retrieval of RDF metadata;
- Replication Service: providing data persistence/availability and workload balancing while maintaining data integrity and consistency;
- Mapping Service: translating between different metadata vocabularies to enable interoperability between different peers;
- Mediation Service: define views that join data from different meta-data sources and reconcile conflicting and overlapping information; and
- Annotation Service: annotate materials stored anywhere within the Edutella Network.