French Grid Research Articles

Asynchronous grid computing for the simulation of the 3D electrophoresis coupled problem

This paper deals with the implementation on the Grid'5000 network, the French grid platform, of parallel simulations for the solution of a 3D coupled boundary value problem. This problem models continuous flow electrophoresis which is governed by Navier Stokes equations coupled with convection-diffusion and potential equations. The coupled boundary value problems are discretised by appropriate schemes involving the convergence of the parallel synchronous and asynchronous Schwarz alternating algorithms. Finally, parallel experiments on grid computing are presented and analyzed.

A large‐scale monitoring and measurement campaign for web services‐based applications

AbstractWeb Services (WS) can be considered as the most influent enabling technology for the next generation of web applications. WS‐based application providers will face challenging features related to nonfunctional properties in general and to performance and QoS in particular. Moreover, WS‐based developers have to provide solutions to extend such applications with self‐healing (SH) mechanisms as required for autonomic computing to face the complexity of interactions and to improve availability. Such solutions should be applicable when the components implementing SH mechanisms are deployed on both or only one platform on the WS providers and requesters sides depending on the deployment constraints. Associating application‐specific performance requirements and monitoring‐specific constraints will lead to complex configurations where fine tuning is needed to provide SH solutions. To contribute to enhancing the design and the assessment of such solutions for WS technology, we designed and implemented a monitoring and measurement framework, which is part of a larger Self‐Healing Architectures (SHA) developed during the European WS‐DIAMOND project. We implemented the Conference Management System (CMS), a real WS‐based complex application. We achieved a large‐scale experimentation campaign by deploying CMS on top of SHA on the French grid Grid5000. We experienced the problem as if we were a service provider who has to tune reconfiguration strategies. Our results are available on the web in a structured database for external use by the WS community. Copyright © 2010 John Wiley & Sons, Ltd.

A rule-driven approach for architectural self adaptation in collaborative activities using graph grammars

Architectural adaptation is important for handling self-configuring properties of autonomic distributed systems. It can be achieved by model-based management of dynamic architectures. Describing dynamic architectures includes defining rules for reconfiguration management. Within this research context, several works have been conducted using formal specification to handle this complexity. Graph and graph rewriting-based approaches showed, through many studies, their appropriateness to tackle architectural adaptation problems. However, scalability of such approaches remains an open issue and has been rarely explored. In this paper, we investigate this issue. We introduce a graph-based general approach for handling of dynamic architectures and we illustrate it within a scenario of collaboration support in crisis management systems. We elaborate the formal models for dynamic architecture management. Using the French Grid GRID5000, we conducted an experimental study to assess the scalability of the elaborated models.

P2P computing for large tree exploration-based exact optimisation

The Branch and Bound (B&B) algorithm is one of the most used methods to solve in an exact way combinatorial optimisation problems. In a previous article, we proposed a new approach of the parallel B&B algorithm for distributed systems using the farmer-worker paradigm. However, the new farmer-worker approach has a disadvantage: some nodes of the B&B tree can be explored by several B&B processes. To prevent this redundant work and speed up, we propose a new P2P approach inspired from the strategies of existing P2P systems like Napster and JXTA. Validation is performed by experimenting the two approaches on mono-objective flow-shop problem benchmarks using 500 processors belonging to the French national grid, Grid'5000. The obtained results prove the efficiency of the proposed P2P approach. Indeed, the execution time obtained with the P2P version, even if more communicative, is better than the farmer-worker's one.

Replication and Update of Molecular Biology Databases

Update of molecular biology databases is a growing burden on the biomedical research community. As the grid allows to share and replicate data, we propose a service to automatically update the molecular biology databases from a single changing reference using Web services. In this paper we report the components, the architecture, and the deployment of the update service on the french RUGBI grid infrastructure. RUGBI is a computing grid infrastructure based on existing middleware and technologies for the community of scientists in bioinformatics.

Conditions techniques de raccordement au réseau public BT ou HTA des installations de production autonome d'énergie électrique

Technical rules for connecting a private power station to the french grid with a voltage level up to 50 kV were defined. These rules are applicable for a new power station since mai 1995.

Quasiperiodic (QP) oscillations in electrical power systems

The occurrence of quasiperiodic (QP) oscillations in power systems, a phenomena hitherto unknown, was first experienced in the French grid when attempting to energize an unloaded transformer at the end of a long transmission line. There are no simple analytical tools available to study conditions for the occurrence of QP oscillations. In this paper, the conditions necessary for the occurrence of quasiperiodicity are shown by solving the system equations using the method of harmonic balance. It is shown that QP oscillations will occur due to the severity of magnetizing nonlinearity of the transformer core. It is also shown that if core losses are high, only frequency locked oscillations can occur. The results are confirmed by numerical solution on the original set of differential equations.

Parallel (quasi-periodic) ferroresonant oscillations in electrical power systems

Quasi-periodic oscillation, hitherto unobserved in power systems, was first experienced in the French grid. Besides obtaining the numerical solution of a set of differential equations or using the method of circle maps, there are no known simple analytical tools available to study conditions for the occurrence of quasi-periodic oscillations. In this paper, quasi-periodic oscillations are analyzed by first neglecting all losses which in effect reduces the dimension of the system. The unperturbed solution for the reduced system is obtained using the method of harmonic balance. The effect of perturbations (losses) on the unperturbed solution are then considered one at a time by using Melnikov function. The geometrical interpretation is confirmed by numerical solution on the original set of differential equations. >

Progress on superconducting current limitation project for the French electrical grid

Electricite de France, GEC ALSTHOM and Alcatel Alsthom Recherche, initiated in project for the definition, experimental validation and economic evaluation of superconducting fault current limiters adapted to the French grid system. As a first step, a device of 63 kV-1.25 kA is investigated, which has the function to limit the 25 kA fault current at 5300 A/sub peak/. A very compact and low-inductance design has been selected, based on resistive limitation. Considerations concerning the general design, conductor protection, high voltage insulation, cryogenic system and interaction with the grid, are developed in this paper.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

De la pénurie à la stratégie ou l'organisation de l'énergie électrique sous l'Occupation en France

Abstract In 1942-43, electricity generation showed a marked upsurge in France. Whilst the Germans doubtless had an interest in seeing the French grid rehabilited, the part played by the Comité d'Organisation de l'Énergie Électrique appears equally unquestionable : not only did ensure that energy output was distributed most efficiently, it also drew up a forward-looking future equipment strategy.

Structural Analysis of the Electrical System: Application to Secondary Voltage Control in France

The voltage control of the French EHV power system is organized in three levels (primary, secondary, and tertiary) which concern distinct geographical areas and time constants. The authors present studies conducted to reach an automatic determination of zones and pilot nodes based on the examination of the structure of the network. The concept of electrical distance has been developed, and its close relationship with the theory of information is underlined. This concept allows the concept of structural controllability and observability of proximity to be extended to the power system. The combined use of this electrical distance and typological analysis algorithms has proven an effective method for the identification of the secondary voltage control zones of the French grid. >

Structural analysis of the electrical system: application to secondary voltage control in France

The voltage control of the French EHV power system is organized in three levels (primary, secondary, and tertiary) which concern distinct geographical areas and time constants. The authors present studies conducted to reach an automatic determination of zones and pilot nodes based on the examination of the structure of the network. The concept of electrical distance has been developed, and its close relationship with the theory of information is underlined. This concept allows the concept of structural controllability and observability of proximity to be extended to the power system. The combined use of this electrical distance and typological analysis algorithms has proven an effective method for the identification of the secondary voltage control zones of the French grid.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Transmission Lines on the French Grid

AN article on “Transmission Lines on the French Grid” by D. J. Tynan-Byrd is published in the Electrical Timesof April 25. The building of the French grid scheme was begun soon after the War of 1914–18, when, owing to the increased industrial and domestic load in different parts of the country, the demand for new generating stations and transmitting stations became urgent. In France, the coalfields lie to the north, and here steam generation to produce electricity is most commonly used. In the southern half of the country, there is abundant water-power available in the Rhone district, in the regions of the French Alps and the Pyrenees, particularly in the spring and summer months when the glaciers begin to melt. The area of France is more than 200,000 square miles, and some regions of dense population possess no facilities for generating electrical· energy, while the regions where facilities are abundant often possess few local inhabitants. Hence the policy adopted is to transmit power from areas where it can be generated cheaply to areas where it is in demand.

The French Grid

The French Grid