ISOPHOT-S: Capabilities and Calibration (Invited Paper)
The in-flight characteristies of ISOPHOT-S are presented, in particular spectral response functio... more The in-flight characteristies of ISOPHOT-S are presented, in particular spectral response function, beam profile, dark current, straylight suppression, and wavelength calibration. Photometric calibration of point-like and extended sources is described. Sensitivity limits and the actual error budget are dis- cussed. The validation of the pipeline products is addressed. Correction methods for signal transients in staring and chopped mode are outiined.
The starburst galaxy NGC 6090: from 2.5 mum to 200mum
Astronomy and …, 1996
... 1995). NGC 6090 has also been observed at 1300 pm (Chini, Krugel, & Kreysa 1993) and ... more ... 1995). NGC 6090 has also been observed at 1300 pm (Chini, Krugel, & Kreysa 1993) and in the UV (Kinney et a!. 1993). Our study in the 2.5 to 200 pm range complement these previous observations, making it an excellent object for a multiwavelength discussion. ...
We have carried out broad band photometry of the interacting galaxy system NGC 6090 from 3.6 to 2... more We have carried out broad band photometry of the interacting galaxy system NGC 6090 from 3.6 to 200 m using ISOPHOT. This is complemented by a l o w resolution spectrum in the wavelength range 2.5-11.5 m: The IR spectral energy distribution of a starburst galaxy is shown with unprecedented detail. From our Far Infrared measurements we can demonstrate that the starburst component is the dominating energy source in this object. 84% of the total IR output is in the wavelength range below 120 m, while 16% is in the 120 to 240 m range. Emission in the PAH bands is an essential radiation mechanism in the wavelength range shortward of 10m for this object. We discuss various published starburst models and their applicability to NGC 6090.
We observed the reflection nebula NGC 7023 at various positions using wide and narrow band photom... more We observed the reflection nebula NGC 7023 at various positions using wide and narrow band photometry centred on the 7.7 and 11.3mum PAH emission features and wide band photometry at 20 and 25mum. No significant variations have been detected over the nebula in the 7.3 and 20mum continuum relative to the total emission in the 6-15mum range (hereafter {GAMMA}). This result supports the hypothesis that most of the continuum emission in both bands come from very small grains. In contrast, the 7.7 and 11.3mum PAH emission features show clear variations. We find that in weaker radiation fields of the nebula the 11.3 and 7.7mum features are not the dominant emission components in the 6-15mum range. The 11.5mum band increases whereas the 11.3mum emission feature decreases relative to {GAMMA} in the outer parts of the nebula. The effect can be explained by increased hydrogenation of PAH molecules.
All observations by the aperture photometer (PHT-P) and the far-infrared (FIR) camera section (PH... more All observations by the aperture photometer (PHT-P) and the far-infrared (FIR) camera section (PHT-C) of ISOPHOT included reference measurements against stable internal fine calibration sources (FCS) to correct for temporal drifts in detector responsivities. The FCSs were absolutely calibrated in-orbit against stars, asteroids and planets, covering wavelengths from 3.2 to 240 µm. We present the calibration concept for point sources within a flux-range from 60 mJy up to 4500 Jy for staring and raster observations in standard configurations and discuss the requisite measurements and the uncertainties involved. In this process we correct for instrumental effects like nonlinearities, signal transients, time variable dark current, misalignments and diffraction effects. A set of formulae is developed that describes the calibration from signal level to flux densities. The scatter of 10 to 20% of the individual data points around the derived calibration relations is a measure of the consistency and typical accuracy of the calibration. The reproducibility over longer periods of time is better than 10%. The calibration tables and algorithms have been implemented in the final versions of the software for offline processing and interactive analysis.
We describe R-GMA (Relational Grid Monitoring Architecture) which is being developed within the E... more We describe R-GMA (Relational Grid Monitoring Architecture) which is being developed within the European DataGrid Project as a Grid Information and Monitoring System for both the grid itself and for use by applications. 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 the information as if each VO had one large relational database. We provide a number of different Producer types with different characteristics; for example some support streaming of information. We also provide combined Consumer/Producers, which are able to combine information and republish it. At the heart of the system is the mediator, which for any query is able to find and connect to the best Producers to do the job. In addition to having some of our own sensors able to publish information, we are able to invoke MDS info-provider scripts and publish the resulting informatio...
The WLCG Authorisation Working Group was formed in July 2017 with the objective to understand and... more The WLCG Authorisation Working Group was formed in July 2017 with the objective to understand and meet the needs of a future-looking Authentication and Authorisation Infrastructure (AAI) for WLCG experiments. Much has changed since the early 2000s when X.509 certificates presented the most suitable choice for authorisation within the grid; progress in token based authorisation and identity federation has provided an interesting alternative with notable advantages in usability and compatibility with external (commercial) partners. The need for interoperability in this new model is paramount as infrastructures and research communities become increasingly interdependent. Over the past two years, the working group has made significant steps towards identifying a system to meet the technical needs highlighted by the community during staged requirements gathering activities. Enhancement work has been possible thanks to externally funded projects, allowing existing AAI solutions to be adap...
Abstract. Grids are complex distributed systems that provide access to computational resources in... more Abstract. Grids are complex distributed systems that provide access to computational resources in a transparent fashion. The task of collecting information about the state of the Grid itself and making it available to other Grid components for querying is called Grid ...
Journal of Physics G: Nuclear and Particle Physics, 2005
The GridPP Collaboration is building a UK computing Grid for particle physics, as part of the int... more The GridPP Collaboration is building a UK computing Grid for particle physics, as part of the international effort towards computing for the Large Hadron Collider. The project, funded by the UK Particle Physics and Astronomy Research Council (PPARC), began in September 2001 and completed its first phase 3 years later. GridPP is a collaboration of approximately 100 researchers in 19 UK university particle physics groups, the Council for the Central Laboratory of the Research Councils and CERN, reflecting the strategic importance of the project. In collaboration with other European and US efforts, the first phase of the project demonstrated the feasibility of developing, deploying and operating a Grid-based computing system to meet the UK needs of the Large Hadron Collider experiments. This note describes the work undertaken to achieve this goal. S Supplementary documentation is available from stacks.iop.org/JPhysG/32/N1. References to sections S1, S2.1, etc are to sections within this online supplement.
This deliverable provides an overview of the operational processes, policies and procedures appli... more This deliverable provides an overview of the operational processes, policies and procedures applicable to the services of the European Open Science Cloud (EOSC) Portfolios. This is achieved by providing a description of the proposed EOSC hub Service Management System including background of its development and plans for future activities.
Computational Methods in Science and Technology, 2006
Advances in networking and distributed computing allowed the establishment of production Grid inf... more Advances in networking and distributed computing allowed the establishment of production Grid infrastructures during the past few years. Today, large-scale production Grid infrastructures such as EGEE in Europe, OSG in the US, and NAREGI in Japan are offering their services to many scientific and industrial applications, from domains as diverse as Astronomy, Biomedicine, Computational Chemistry, Earth Sciences, Financial Simulations, and High Energy Physics. Grid infrastructures provide these applications a new means for collaborative research by facilitating the sharing of computational and data resources at an unprecedented scale. The efficient and secure sharing of data resources, which can reach several Tera-to Petabytes in some application domains, is one of the main challenges for Grid infrastructures. The Enabling Grid for E-sciencE project (EGEE) is Europe's flagship Research Infrastructures Grid project and the world's largest Grid infrastructure of its kind. It involves more than 70 partners from 27 countries, arranged in twelve regional federations, and providing more than 20,000 CPUs, almost 200 sites and 10 petabytes of available network storage. This infrastructure supports 7 scientific domains and more than 20 individual applications. Started in April 2004, EGEE has rapidly grown from a European to a global endeavor, and along the way learned a great deal about the business of building production-quality infrastructure. The consortium behind this effort represents a significant proportion of Europe's Grid experts, including not only academic institutions but also partners form the Research Network community and European industry. Grid systems and applications aim to integrate, virtualise, and manage resources and services within distributed, heterogeneous, dynamic Virtual Organisations across traditional administrative and organisational domains (real organisations) .
Proceedings of EGI Community Forum 2012 / EMI Second Technical Conference — PoS(EGICF12-EMITC2)
This provides an overview of the activities of the European Grid Infrastructure (EGI) Software Vu... more This provides an overview of the activities of the European Grid Infrastructure (EGI) Software Vulnerability Group (SVG) and progress made in addressing vulnerabilities in collaboration with the European Middleware Initiative (EMI). This includes a summary of the formally agreed process for handling Software Vulnerabilities reported to the EGI SVG. It also describes the pro-active searching for vulnerabilities via 'Vulnerability Assessment' of software packages. Steps taken to prevent new vulnerabilities entering the infrastructure are described. The emphasis is on Grid Middleware as vulnerabilities in this software are generally not handled elsewhere. The collaboration with the Grid middleware software providers, in particular EMI, is described.
Proceedings of SPIE - The International Society for Optical Engineering
The imaging photopolarimeter ISOPHOT on-board the European satellite ISO houses 144 background de... more The imaging photopolarimeter ISOPHOT on-board the European satellite ISO houses 144 background detectors of Si:Ga, Si:P, Ge:Ga and stressed Ge:Ga, all sampled by newly developed cold read-out electronics. There is large temporal radiation damage to most of these detectors on the daily passage through the earth's radiation belts. In addition the Ge:Ga detectors exhibit a continuous responsivity increase caused by
EU DataGrid and GridPP Authorization and Access Control
This paper describes ways in which authorization information is published for use on the GridPP T... more This paper describes ways in which authorization information is published for use on the GridPP Testbed, and how it is used to control access to local resources, such as Unix accounts, disk filesystems and the virtual filesystems exported by file and web servers
The R-GMA (Relational Grid Monitoring Architecture) was developed within the EU DataGrid project,... more The R-GMA (Relational Grid Monitoring Architecture) was developed within the EU DataGrid project, to bring the power of SQL to an information and monitoring system for the grid. It provides producer and consumer services to both publish and retrieve information from anywhere within a grid environment. Users within a Virtual Organization may define their own tables dynamically into which to publish data. Within the DataGrid project R-GMA was used for the information system, making details about grid resources available for use by other middleware components. R-GMA has also been used for monitoring grid jobs by members of the CMS and D0 collaborations where information about jobs is published from within a job wrapper, transported across the grid by R-GMA and made available to users. An accounting package for processing PBS logging data and sending it to one or more Grid Operation Centres using R-GMA has been written and is being deployed within LCG. There are many other existing and ...
Multiple Virtual Databases to Support Multiple VOs in R-GMA
R-GMA is a relational implementation of the GGF's Grid Monitoring Architecture (GMA). In some... more R-GMA is a relational implementation of the GGF's Grid Monitoring Architecture (GMA). In some respects it can be seen as a virtual database (VDB), supporting the publishing and retrieval of time-stamped tuples. The scope of an R-GMA installation is defined by its schema and registry. The schema holds the table definitions and, in future, the authorization rules. The registry holds a list of the available producers and consumers. At present, while it is possible to have multiple installations, a user can only use one at a time and hence cannot access tables in another installation. We plan to introduce multiple VDBs, where each VDB is defined by its own registry and schema. In this paper we explain the basic idea of R-GMA, why we need multiple VDBs to support multiple VOs, and how we will implement them. We also discuss the possible need to create some VDBs not related to end-user VOs. We also explain why we do not plan to provide a catalogue of VDBs as a part of R-GMA.
SANTA-G: an instrument monitoring framework for the Grid
In this paper we describe SANTA-G (Grid-enabled System Area Networks Trace Analysis) an instrumen... more In this paper we describe SANTA-G (Grid-enabled System Area Networks Trace Analysis) an instrument monitoring framework that uses the R-GMA (Relational Grid Monitoring Architecture). We de-scribe the R-GMA component that allows for instrument monitoring, the CanonicalProducer. We also describe an example use of this approach in the European CrossGrid project, the SANTA-G Network Tracer, a network monitoring tool.
We describe R-GMA (Relational Grid Monitoring Architecture) which has been developed within the E... 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 the information as if each Virtual Organisation had one large relational database. We provide a number of different Producer types with different characteristics; for example some support streaming of information. We also provide combined Consumer/Producers, which are able to combine information and republish it. At the heart of the system is the mediator, which for any query is able to find and connect to the best Producers for the job. We have developed components to allow a measure of inter-working between MDS and R-GMA. We have used it both for information about the grid (primarily to find out about what services are available...
ISOPHOT-S: Capabilities and Calibration (Invited Paper)
The in-flight characteristies of ISOPHOT-S are presented, in particular spectral response functio... more The in-flight characteristies of ISOPHOT-S are presented, in particular spectral response function, beam profile, dark current, straylight suppression, and wavelength calibration. Photometric calibration of point-like and extended sources is described. Sensitivity limits and the actual error budget are dis- cussed. The validation of the pipeline products is addressed. Correction methods for signal transients in staring and chopped mode are outiined.
The starburst galaxy NGC 6090: from 2.5 mum to 200mum
Astronomy and …, 1996
... 1995). NGC 6090 has also been observed at 1300 pm (Chini, Krugel, & Kreysa 1993) and ... more ... 1995). NGC 6090 has also been observed at 1300 pm (Chini, Krugel, & Kreysa 1993) and in the UV (Kinney et a!. 1993). Our study in the 2.5 to 200 pm range complement these previous observations, making it an excellent object for a multiwavelength discussion. ...
We have carried out broad band photometry of the interacting galaxy system NGC 6090 from 3.6 to 2... more We have carried out broad band photometry of the interacting galaxy system NGC 6090 from 3.6 to 200 m using ISOPHOT. This is complemented by a l o w resolution spectrum in the wavelength range 2.5-11.5 m: The IR spectral energy distribution of a starburst galaxy is shown with unprecedented detail. From our Far Infrared measurements we can demonstrate that the starburst component is the dominating energy source in this object. 84% of the total IR output is in the wavelength range below 120 m, while 16% is in the 120 to 240 m range. Emission in the PAH bands is an essential radiation mechanism in the wavelength range shortward of 10m for this object. We discuss various published starburst models and their applicability to NGC 6090.
We observed the reflection nebula NGC 7023 at various positions using wide and narrow band photom... more We observed the reflection nebula NGC 7023 at various positions using wide and narrow band photometry centred on the 7.7 and 11.3mum PAH emission features and wide band photometry at 20 and 25mum. No significant variations have been detected over the nebula in the 7.3 and 20mum continuum relative to the total emission in the 6-15mum range (hereafter {GAMMA}). This result supports the hypothesis that most of the continuum emission in both bands come from very small grains. In contrast, the 7.7 and 11.3mum PAH emission features show clear variations. We find that in weaker radiation fields of the nebula the 11.3 and 7.7mum features are not the dominant emission components in the 6-15mum range. The 11.5mum band increases whereas the 11.3mum emission feature decreases relative to {GAMMA} in the outer parts of the nebula. The effect can be explained by increased hydrogenation of PAH molecules.
All observations by the aperture photometer (PHT-P) and the far-infrared (FIR) camera section (PH... more All observations by the aperture photometer (PHT-P) and the far-infrared (FIR) camera section (PHT-C) of ISOPHOT included reference measurements against stable internal fine calibration sources (FCS) to correct for temporal drifts in detector responsivities. The FCSs were absolutely calibrated in-orbit against stars, asteroids and planets, covering wavelengths from 3.2 to 240 µm. We present the calibration concept for point sources within a flux-range from 60 mJy up to 4500 Jy for staring and raster observations in standard configurations and discuss the requisite measurements and the uncertainties involved. In this process we correct for instrumental effects like nonlinearities, signal transients, time variable dark current, misalignments and diffraction effects. A set of formulae is developed that describes the calibration from signal level to flux densities. The scatter of 10 to 20% of the individual data points around the derived calibration relations is a measure of the consistency and typical accuracy of the calibration. The reproducibility over longer periods of time is better than 10%. The calibration tables and algorithms have been implemented in the final versions of the software for offline processing and interactive analysis.
We describe R-GMA (Relational Grid Monitoring Architecture) which is being developed within the E... more We describe R-GMA (Relational Grid Monitoring Architecture) which is being developed within the European DataGrid Project as a Grid Information and Monitoring System for both the grid itself and for use by applications. 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 the information as if each VO had one large relational database. We provide a number of different Producer types with different characteristics; for example some support streaming of information. We also provide combined Consumer/Producers, which are able to combine information and republish it. At the heart of the system is the mediator, which for any query is able to find and connect to the best Producers to do the job. In addition to having some of our own sensors able to publish information, we are able to invoke MDS info-provider scripts and publish the resulting informatio...
The WLCG Authorisation Working Group was formed in July 2017 with the objective to understand and... more The WLCG Authorisation Working Group was formed in July 2017 with the objective to understand and meet the needs of a future-looking Authentication and Authorisation Infrastructure (AAI) for WLCG experiments. Much has changed since the early 2000s when X.509 certificates presented the most suitable choice for authorisation within the grid; progress in token based authorisation and identity federation has provided an interesting alternative with notable advantages in usability and compatibility with external (commercial) partners. The need for interoperability in this new model is paramount as infrastructures and research communities become increasingly interdependent. Over the past two years, the working group has made significant steps towards identifying a system to meet the technical needs highlighted by the community during staged requirements gathering activities. Enhancement work has been possible thanks to externally funded projects, allowing existing AAI solutions to be adap...
Abstract. Grids are complex distributed systems that provide access to computational resources in... more Abstract. Grids are complex distributed systems that provide access to computational resources in a transparent fashion. The task of collecting information about the state of the Grid itself and making it available to other Grid components for querying is called Grid ...
Journal of Physics G: Nuclear and Particle Physics, 2005
The GridPP Collaboration is building a UK computing Grid for particle physics, as part of the int... more The GridPP Collaboration is building a UK computing Grid for particle physics, as part of the international effort towards computing for the Large Hadron Collider. The project, funded by the UK Particle Physics and Astronomy Research Council (PPARC), began in September 2001 and completed its first phase 3 years later. GridPP is a collaboration of approximately 100 researchers in 19 UK university particle physics groups, the Council for the Central Laboratory of the Research Councils and CERN, reflecting the strategic importance of the project. In collaboration with other European and US efforts, the first phase of the project demonstrated the feasibility of developing, deploying and operating a Grid-based computing system to meet the UK needs of the Large Hadron Collider experiments. This note describes the work undertaken to achieve this goal. S Supplementary documentation is available from stacks.iop.org/JPhysG/32/N1. References to sections S1, S2.1, etc are to sections within this online supplement.
This deliverable provides an overview of the operational processes, policies and procedures appli... more This deliverable provides an overview of the operational processes, policies and procedures applicable to the services of the European Open Science Cloud (EOSC) Portfolios. This is achieved by providing a description of the proposed EOSC hub Service Management System including background of its development and plans for future activities.
Computational Methods in Science and Technology, 2006
Advances in networking and distributed computing allowed the establishment of production Grid inf... more Advances in networking and distributed computing allowed the establishment of production Grid infrastructures during the past few years. Today, large-scale production Grid infrastructures such as EGEE in Europe, OSG in the US, and NAREGI in Japan are offering their services to many scientific and industrial applications, from domains as diverse as Astronomy, Biomedicine, Computational Chemistry, Earth Sciences, Financial Simulations, and High Energy Physics. Grid infrastructures provide these applications a new means for collaborative research by facilitating the sharing of computational and data resources at an unprecedented scale. The efficient and secure sharing of data resources, which can reach several Tera-to Petabytes in some application domains, is one of the main challenges for Grid infrastructures. The Enabling Grid for E-sciencE project (EGEE) is Europe's flagship Research Infrastructures Grid project and the world's largest Grid infrastructure of its kind. It involves more than 70 partners from 27 countries, arranged in twelve regional federations, and providing more than 20,000 CPUs, almost 200 sites and 10 petabytes of available network storage. This infrastructure supports 7 scientific domains and more than 20 individual applications. Started in April 2004, EGEE has rapidly grown from a European to a global endeavor, and along the way learned a great deal about the business of building production-quality infrastructure. The consortium behind this effort represents a significant proportion of Europe's Grid experts, including not only academic institutions but also partners form the Research Network community and European industry. Grid systems and applications aim to integrate, virtualise, and manage resources and services within distributed, heterogeneous, dynamic Virtual Organisations across traditional administrative and organisational domains (real organisations) .
Proceedings of EGI Community Forum 2012 / EMI Second Technical Conference — PoS(EGICF12-EMITC2)
This provides an overview of the activities of the European Grid Infrastructure (EGI) Software Vu... more This provides an overview of the activities of the European Grid Infrastructure (EGI) Software Vulnerability Group (SVG) and progress made in addressing vulnerabilities in collaboration with the European Middleware Initiative (EMI). This includes a summary of the formally agreed process for handling Software Vulnerabilities reported to the EGI SVG. It also describes the pro-active searching for vulnerabilities via 'Vulnerability Assessment' of software packages. Steps taken to prevent new vulnerabilities entering the infrastructure are described. The emphasis is on Grid Middleware as vulnerabilities in this software are generally not handled elsewhere. The collaboration with the Grid middleware software providers, in particular EMI, is described.
Proceedings of SPIE - The International Society for Optical Engineering
The imaging photopolarimeter ISOPHOT on-board the European satellite ISO houses 144 background de... more The imaging photopolarimeter ISOPHOT on-board the European satellite ISO houses 144 background detectors of Si:Ga, Si:P, Ge:Ga and stressed Ge:Ga, all sampled by newly developed cold read-out electronics. There is large temporal radiation damage to most of these detectors on the daily passage through the earth's radiation belts. In addition the Ge:Ga detectors exhibit a continuous responsivity increase caused by
EU DataGrid and GridPP Authorization and Access Control
This paper describes ways in which authorization information is published for use on the GridPP T... more This paper describes ways in which authorization information is published for use on the GridPP Testbed, and how it is used to control access to local resources, such as Unix accounts, disk filesystems and the virtual filesystems exported by file and web servers
The R-GMA (Relational Grid Monitoring Architecture) was developed within the EU DataGrid project,... more The R-GMA (Relational Grid Monitoring Architecture) was developed within the EU DataGrid project, to bring the power of SQL to an information and monitoring system for the grid. It provides producer and consumer services to both publish and retrieve information from anywhere within a grid environment. Users within a Virtual Organization may define their own tables dynamically into which to publish data. Within the DataGrid project R-GMA was used for the information system, making details about grid resources available for use by other middleware components. R-GMA has also been used for monitoring grid jobs by members of the CMS and D0 collaborations where information about jobs is published from within a job wrapper, transported across the grid by R-GMA and made available to users. An accounting package for processing PBS logging data and sending it to one or more Grid Operation Centres using R-GMA has been written and is being deployed within LCG. There are many other existing and ...
Multiple Virtual Databases to Support Multiple VOs in R-GMA
R-GMA is a relational implementation of the GGF's Grid Monitoring Architecture (GMA). In some... more R-GMA is a relational implementation of the GGF's Grid Monitoring Architecture (GMA). In some respects it can be seen as a virtual database (VDB), supporting the publishing and retrieval of time-stamped tuples. The scope of an R-GMA installation is defined by its schema and registry. The schema holds the table definitions and, in future, the authorization rules. The registry holds a list of the available producers and consumers. At present, while it is possible to have multiple installations, a user can only use one at a time and hence cannot access tables in another installation. We plan to introduce multiple VDBs, where each VDB is defined by its own registry and schema. In this paper we explain the basic idea of R-GMA, why we need multiple VDBs to support multiple VOs, and how we will implement them. We also discuss the possible need to create some VDBs not related to end-user VOs. We also explain why we do not plan to provide a catalogue of VDBs as a part of R-GMA.
SANTA-G: an instrument monitoring framework for the Grid
In this paper we describe SANTA-G (Grid-enabled System Area Networks Trace Analysis) an instrumen... more In this paper we describe SANTA-G (Grid-enabled System Area Networks Trace Analysis) an instrument monitoring framework that uses the R-GMA (Relational Grid Monitoring Architecture). We de-scribe the R-GMA component that allows for instrument monitoring, the CanonicalProducer. We also describe an example use of this approach in the European CrossGrid project, the SANTA-G Network Tracer, a network monitoring tool.
We describe R-GMA (Relational Grid Monitoring Architecture) which has been developed within the E... 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 the information as if each Virtual Organisation had one large relational database. We provide a number of different Producer types with different characteristics; for example some support streaming of information. We also provide combined Consumer/Producers, which are able to combine information and republish it. At the heart of the system is the mediator, which for any query is able to find and connect to the best Producers for the job. We have developed components to allow a measure of inter-working between MDS and R-GMA. We have used it both for information about the grid (primarily to find out about what services are available...
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Papers by Linda Cornwall