1,385 research outputs found
Modular System for Shelves and Coasts (MOSSCO v1.0) - a flexible and multi-component framework for coupled coastal ocean ecosystem modelling
Shelf and coastal sea processes extend from the atmosphere through the water
column and into the sea bed. These processes are driven by physical, chemical,
and biological interactions at local scales, and they are influenced by
transport and cross strong spatial gradients. The linkages between domains and
many different processes are not adequately described in current model systems.
Their limited integration level in part reflects lacking modularity and
flexibility; this shortcoming hinders the exchange of data and model components
and has historically imposed supremacy of specific physical driver models. We
here present the Modular System for Shelves and Coasts (MOSSCO,
http://www.mossco.de), a novel domain and process coupling system
tailored---but not limited--- to the coupling challenges of and applications in
the coastal ocean. MOSSCO builds on the existing coupling technology Earth
System Modeling Framework and on the Framework for Aquatic Biogeochemical
Models, thereby creating a unique level of modularity in both domain and
process coupling; the new framework adds rich metadata, flexible scheduling,
configurations that allow several tens of models to be coupled, and tested
setups for coastal coupled applications. That way, MOSSCO addresses the
technology needs of a growing marine coastal Earth System community that
encompasses very different disciplines, numerical tools, and research
questions.Comment: 30 pages, 6 figures, submitted to Geoscientific Model Development
Discussion
A Service-Oriented Architecture enabling dynamic services grouping for optimizing distributed workflows execution
International audienceIn this paper, we describe a Service-Oriented Architecture allowing the optimization of the execution of service workflows. We discuss the advantages of the service-oriented approach with regard to the enactment of scientific applications on a grid infrastructure. Based on the development of a generic Web-Services wrapper, we show how the flexibility of our architecture enables dynamic service grouping for optimizing the application execution time. We demonstrate performance results on a real medical imaging application. On a production grid infrastructure, the optimization proposed introduces a significant speed-up (from 1.2 to 2.9) when compared to a traditional execution
OGSA first impressions: a case study re-engineering a scientific applicationwith the open grid services architecture
We present a case study of our experience re-engineeringa scientific application using the Open Grid Services Architecture(OGSA), a new specification for developing Gridapplications using web service technologies such as WSDLand SOAP. During the last decade, UCL?s Chemistry departmenthas developed a computational approach for predictingthe crystal structures of small molecules. However,each search involves running large iterations of computationallyexpensive calculations and currently takes a fewmonths to perform. Making use of early implementationsof the OGSA specification we have wrapped the Fortranbinaries into OGSI-compliant service interfaces to exposethe existing scientific application as a set of loosely coupledweb services. We show how the OGSA implementationfacilitates the distribution of such applications across alarge network, radically improving performance of the systemthrough parallel CPU capacity, coordinated resourcemanagement and automation of the computational process.We discuss the difficulties that we encountered turning Fortranexecutables into OGSA services and delivering a robust,scalable system. One unusual aspect of our approachis the way we transfer input and output data for the Fortrancodes. Instead of employing a file transfer service wetransform the XML encoded data in the SOAP message tonative file format, where possible using XSLT stylesheets.We also discuss a computational workflow service that enablesusers to distribute and manage parts of the computationalprocess across different clusters and administrativedomains. We examine how our experience re-engineeringthe polymorph prediction application led to this approachand to what extent our efforts have succeeded
Security mechanisms for legacy code applications in GT3 environment
There are many legacy code applications that cannot be
run in Grid environment without significant modifications.
To avoid re-engineering of legacy code, we developed the
Grid Execution Management for Legacy Code Architecture
(GEMLCA) that enables deployment of legacy code
applications as Grid services. GEMLCA is an OGSI Grid
service layer that supports submitting jobs, getting their
results and status back. Security requirements are essential
to any Grid application to preserve the confidentiality and
integrity of data. To meet these requirements the GT3
security model was implemented in GEMLCA. The paper
introduces GEMLCA and how Grid Security Infrastructure
(GSI) components have been added to GEMLCA in order
to enable secure execution of jobs in Grid. The paper also
presents how a legacy code traffic simulator was transformed into a Grid service using GEMLCA and gives some simulation results
High-level grid application environment to use legacy codes as OGSA grid services
One of the biggest obstacles in the wide-spread industrial
take-up of Grid technology is the existence of a large
amount of legacy code that is not accessible as Grid services.
The paper describes a new approach (GEMLCA: Grid Execution Management for Legacy Code Architecture) to deploy legacy codes as Grid services without modifying the original code. Moreover, we show a workflow execution oriented Grid portal technology (P-GRADE portal) by which such legacy code based Grid services can be applied in complex business processes. GEMLCA has been implemented as GT-3 services but can be easily ported into the new WSRF Grid standards
Integrated framework for development and execution of component-based Grid applications
Component-based software technologies have emerged as a modern approach to software development for distributed and grid applications. However, the lack of longer-term experience and the complexity of the target systems demand more research results in the field. This paper provides an overview of three different approaches to developing component- based grid applications. In order to re-use legacy codes, the wrapper software approach can be adopted in its two flavours - hand-written or automatically generated wrapper code. Another approach applicable to existing object-oriented software is to componentise the code by introducing appropriate modifications. The third approach is component-oriented development from scratch. We compare and contrast the three approaches and highlight their advantages and weaknesses
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