The Open Overlays Collaborative Workspace

Chris Cooper, David Duce, Wei Li, Musbah Sagar (Oxford Brookes University)

Gordon Blair, Geoff Coulson, Paul Grace (Lancaster University)

This paper describes a collaborative workspace tool being developed at Oxford Brookes University as part of the Open Overlays project. This project is concerned with fundamental research relating to advanced middleware and advanced networking - and, crucially, an approach that integrates these two key areas. Work in the project is focused on integration of a component oriented middleware platform oriented toward next-generation Gridware with an extensible set of interaction types and advanced network services, and on an architectural framework for the internals of future Grid middleware.

We have developed an application scenario based on wildfire management. We are considering (with advice from environmental scientists/geographers at Royal Holloway University of London and The Open University) a scenario based on a remote region with poor accessibility. Fire fighters in this scenario have very limited means at their disposal: aerial attack is not possible, the main instruments for fire-fighting are hand beaters and pre-cut fire breaks (which in general will have become overgrown). The fire-fighters have little idea where the fire boundary is and there is no communication between different groups of fighters. In the scenario, we posit a number of advances:

The scenario contains a number of different types of actors:

We are using SVG in the development of a prototype collaborative workspace tool which is the basis for graphical communication between controllers, controllers and field workers and field worker to field worker. Graphical communication will be used to present map information, overlayed with visualizations of sensor information (including positions of actors). Controllers and field workers will be able to sketch on the drawing surface, for example to give an estimate of the loal fire boundary, or to highlight particular features.

We are developing the workspace tool using SVG and RDF. The main ideas being explored are:

We perceive a number of benefits in this approach for this scenario.

We are developing the tool using a group interface provided by the middleware being developed by our partners in the project at the University of Lancaster. The group interface facilitates dissemination of updates to relevant actors and to the RDF repository. We are considering both a centralised repository and a locally developed distributed repository, based on distributed hash tables, inspired by RDFPeers (Cai and Frank, 2004). The middleware framework should allow the shared workspace to move seemlessly from a centralised implementation of the RDF repository to a distributed implementation at run-time.

The work also draws inspiration from W3C's Annotea project. There are similiarities too with the work of Qiu, Carpenter and Fox though we are using a very different middleware environment to their's and their approach does not use RDF.

In the paper we will discuss the design, architecture and implementation of the prototype. The paper will conclude with a discussion of future directions the work is taking.


  1. Open Overlays project web site, See [accessed 4 February 2005]
  2. Min Cai and Martin Frank, RDFPeers: A Scalable Distributed RDF Repository based on a Structured Peer-to-Peer Network, WWW 2004, pp. 650-657, ACM Press, 2004.
  3. W3C Annotea project. See [accessed 4 February 2005]
  4. Xiaohong Qiu, Bryan Carpenter and Geoffrey C. Fox, Collaborative SVG as A Web Service, SVG Open 2003. [accessed 4 February 2005]

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