Approach of Data and Information collection for the Decision Support in Industrial Asset Management: Keynote

International audienc

A hybrid closed queuing network approach to model dataflow in networked distributed processors

International audienceIn this paper, a hybrid closed queuing network model has been proposed to model dataflow in networked distributed processing systems. Multi-threading is useful in reducing the latency by switching among a set of threads in order to improve the processor utilization. Two sets of processors, synchronization and execution processors exist. Synchronization processors handle load/store operations and execution processors handle arithmetic/logic and control operations. A closed queuing network model is suitable for large number of job arrivals. Both single server and multiple server models are discussed. The normalization constant is derived using a recursive algorithm for the given model. Performance measures such as average response times and average system throughput are derived and plotted against the total number of processors in the closed queuing network model. Other important performance measures like processor utilizations, average queue lengths, average waiting times and relative utilizations are also derived

Requirements and issues of data and Information for the decision support in industrial asset management

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Cumulative diagnosis strategy for predictive maintenance decision support

International audienceWe propose a new diagnosis strategy, here called "cumulative diagnosis", for advanced decision support to predictive maintenance. It is based on the cumulative damage principle and the use the degradation laws of the considered components. The main objectives of this strategy include the reduction of the cost of diagnoses per time unit and the improvement of the systems' availability. The strategy requires establishing and composing three models: resources allocation to the diagnosis tasks under exclusiveness constraint; diagnosis tasks scheduling under precedence constraints; and a dynamic model of tasks' planning in real-time over periodic, a-periodic and stochastic time windows. The obtained models are integrated to support the predictive maintenance decisions. The new diagnosis strategy has several advantages and its performances may be appreciated through the experimental results of evaluation

A hybrid closed queuing network approach to model dataflow in networked distributed processors

International audienceIn this paper, a hybrid closed queuing network model has been proposed to model dataflow in networked distributed processing systems. Multi-threading is useful in reducing the latency by switching among a set of threads in order to improve the processor utilization. Two sets of processors, synchronization and execution processors exist. Synchronization processors handle load/store operations and execution processors handle arithmetic/logic and control operations. A closed queuing network model is suitable for large number of job arrivals. Both single server and multiple server models are discussed. The normalization constant is derived using a recursive algorithm for the given model. Performance measures such as average response times and average system throughput are derived and plotted against the total number of processors in the closed queuing network model. Other important performance measures like processor utilizations, average queue lengths, average waiting times and relative utilizations are also derived

Modèle de gestion décentralisée et à distance de la maintenance d'un système réparti

International audienceCet article décrit un modèle de gestion décentralisée de la maintenance de machines, équipements ou entités répartis. Conçu dans une approche de soutien logistique, ce modèle basé sur le concept de service “e- maintenance” apporte un service de maintenance optimale aux systèmes en exploitation. Il permet la gestion réactive des ressources de maintenance (ressources humaines, pièces de rechanges) ainsi que la gestion réactive des tâches de diagnostic et de maintenance en vue d’assurer la disponibilité optimale des machines en éliminant les arrêts de production dus aux défaillances. Après une analyse du problème global de disponibilité des équipements répartis, nous proposons une structure d’organisation de la maintenance ainsi que des stratégies de gestion des différents types de ressource. Ensuite, nous présentons un ensemble de méthodes applicables à la résolution des problèmes de gestion réactive. Enfin, nous proposons un modèle ("plate forme logicielle de simulation et évaluation de performances" paramétrable, d'optimisation et de simulation des processus de gestion décentralisée de la maintenance des systèmes répartis (concept e- maintenance service)

Reliability databases: principles and construction

International audienceTo facilitate users search for information on systems or components and surveys of historical data (design, test results and failures of components, date and duration of system maintenance,...) for dependability needs, data are stored in data banks or databases. These needs are of several types: availability and logistics needs of military equipment and the need for safety in hazardous industries, designers, manufacturers and managers responsible for installations, etc. This paper presents the basic concepts which guide the construction of a reliability database. For this purpose, the principal definitions related to reliability data as well as the principal methods used for reliability data collection, are given. Finally, some of the best-known databases are presented, followed by the principles of database management systems

Optimization of k/n-serial systems reliability by using genetic algorithms: three possible formulations

International audienceThis paper investigates the optimization of k/n serial system, which is a mixed discrete and continue combinatorial optimization problem. Three formulations of the problem are solved, including multi-objective optimization formulation. The formulations are NP-hard, and the objective functions obtained after constraint relaxation by penalty method are not derivable. So, genetic algorithms are used to solve these formulations of k/n optimization problems. The proposed algorithm gives suitable results with reasonable computing time.Dans ce papier, nous cherchons à optimiser un système série de type k/n qui constitue un problème d'optimisation combinatoire à la fois discrète et continue. Trois formulations différentes du problème incluant la forme d'optimisation multi-objectif, sont résolues. Les formulations sont non seulement NP-difficiles, mais en plus les fonctions objectives obtenues après relaxation des contraintes par la méthode de pénalité sont non dérivables. Les algorithmes génétiques ont donc été utilisés pour résoudre le problème d'optimisation sous ses différentes formulations. L'algorithme proposé donne des résultats convenables avec des temps de calculs informatiques raisonnables

A framework for FSM based multi-model approach to interconnected components' network

International audienceThis paper presents a framework of multi-model based approach for interconnected components network by finite state machine model. The main concept on which we base our approach is the fact that, in a context of interconnected components, due to the influence of some components named here key-components the system can switch from one mode to another. The influence of these components can be measured by the level of involvement in the switching events. The proposed approach can be applied to embedded systems in which we propose to consider the controller as a part of the system

Etude du risque pour une approche systémique de la sécurité

International audienceCe papier propose un cadre d’étude et d’évaluation du risque systémique dans un contexte de sécurité. Nous présentons dans un premier temps la démarche systémique de la sécurité sur laquelle se base la construction d’un modèle pertinent du risque. A l’aide de ce modèle, nous proposons un diagramme de suivi de la conjonction de phénomènes qui conduisent à la naissance d’un accident. Ce diagramme peut avoir pour extension le suivi d’un système qui évolue alors en « mode catastrophe » en présence d’une crise majeure et en l’absence de contre-mesures.Notre étude se termine par la mise en évidence de quelques défis que soulève cette approche du risque systémique