Atlas is a peer-to-peer network for the distributed storage, querying and update of RDF(S) metadata describing Web or Grid resources. We use state of the art DHT technology to design and implement a distributed system that is able to scale to large numbers of nodes of nodes and handle large amounts of RDF(S) data. Atlas is implemented on top of the Bamboo DHT
Atlas nodes can store RDF(S) data and pose RQL
queries. In the typical Atlas application that we envision, RDF(S) data will be used to describe resources owned by network nodes (e.g., ontologies or services).
Atlas support one-time queries (information pull scenarios) and continuous queries (information push scenarios). A simple information pull scenario in which Atlas can be used for service discovery is as follows. When a network node has a service that it wishes to make available to the rest of the network, it creates and publishes RDF metadata about this service using a service description language e.g., OWL-S. Later on, this service can possibly be discovered by another node that poses an RQL query to discover services that it needs.
The development of Atlas started in the context of European FP6 project OntoGrid
. OntoGrid was a pioneering effort in the area of the Semantic Grid funded by the European Commission. In OntoGrid, Atlas is used as part of the metadata service. The metadata service uses Atlas as a distributed RDF database to store, query and update various kinds of metadata produced by other OntoGrid components.
The project "Peer-to-Peer techniques for Semantic Web Services" supported further development of Atlas. This project is a collaboration between our group and Katia Sycara
's group from the Robotics Institute
, Carnegie Mellon University
Starting September 2008, Atlas is being utilized in the FP7 STREP project "SemsorGrid4Env: Semantic Sensor Grids for Rapid Application Development for Environmental Management" in which our group participates. Atlas is the distributed implementation of stSPARQL that form the basis of the distributed Semantic Registry implementation of SemsorGrid4Env.