David O'Callaghan

Learn More
We have developed and implemented the Relational Grid Monitoring Architecture (R-GMA) as part of the DataGrid project, to provide a flexible information and monitoring service for use by other middleware components and applications. R-GMA presents users with a virtual database and mediates queries posed at this database: users pose queries against a global(More)
Computational Grids are distributed systems that provide access to computational resources in a transparent fashion. Collecting and providing information about the status of the Grid itself is called Grid monitoring. We describe R-GMA (Relational Grid Monitoring Architecture) as a solution to the Grid monitoring problem. It uses a local as view approach to(More)
We describe R-GMA (Relational Grid Monitoring Architecture) which has been developed within the European DataGrid Project as a Grid Information and Monitoring System. Is is based on the GMA from GGF, which is a simple Consumer-Producer model. The special strength of this implementation comes from the power of the relational model. We offer a global view of(More)
Grid middleware is enabling resource sharing between computing centres across the world and sites with existing clusters are eager to connect to the Grid. However, the hardware requirements for access to the Grid remain high: a standard Grid gateway requires four separate servers. We propose the use of Virtual Machine (VM) technology to run multiple OS(More)
This article discusses the authentication and the authorization aspects of security in grid environments spanning multiple administrative domains. Achievements in these areas are presented using the EU DataGrid project as an example implementation. It also gives an outlook on future directions of development.
Grid-Ireland, the national computational grid for Ireland, has a centrally managed core infrastructure: the installation and configuration of grid gateways at constituent sites is controlled from an Operations Centre based at Trinity College Dublin. This structure has necessitated the development of tools to automate and simplify the deployment of(More)
To be successful the grid must serve a variety of application domains. The data management solutions offered by existing grid middleware have significant shortcomings with respect to the needs of some of these application domains. This paper attributes these shortages to a lack of an underlying grid storage infrastructure, similar to that within an(More)
The Certification Authority Coordination Group in the European DataGrid project has created a unique large-scale Public Key Infrastructure and the policies and procedures to operate it successfully. The infrastructure demonstrates interoperability of multiple certification authorities (CAs) with various technical resources in a novel system of(More)
  • Jean-Philippe Lavigne, Annette C. Vergunst, Lucie Goret, Albert Sotto, Christophe Combescure, Jorge Blanco +2 others
  • 2012
Recently, the worldwide propagation of clonal CTX-M-15-producing Escherichia coli isolates, namely ST131 and O25b:H4, has been reported. Like the majority of extra-intestinal pathogenic E. coli isolates, the pandemic clone ST131 belongs to phylogenetic group B2, and has recently been shown to be highly virulent in a mouse model, even though it lacks several(More)