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Статті в журналах з теми "Evaluation probabiliste des fautes":
1
Duprat, Frédéric, Alain Sellier, and Laurie Lacarrière. "Evaluation probabiliste du risque de corrosion par carbonatation." Revue Française de Génie Civil 8, no. 8 (November 2004): 975–97. http://dx.doi.org/10.1080/12795119.2004.9692637.
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Bourguignon, N., B. Veber, S. Godier, N. Frebourg, J. F. Lemeland, and B. Dureuil. "Evaluation de l'antibiothérapie probabiliste des péritonites post-opératoires en réanimation." Annales Françaises d'Anesthésie et de Réanimation 16, no. 6 (September 1997): 762. http://dx.doi.org/10.1016/s0750-7658(97)86322-8.
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Paradisopoulou, P. M., E. E. Papadimitriou, and J. Mirek. "SIGNIFICANT EARTHQUAKES NEAR THE CITY OF THESSALONIKI (NORTHERN GREECE) AND PROBABILITY DISTRIBUTION ON FAULTS." Bulletin of the Geological Society of Greece 50, no. 3 (July 27, 2017): 1389. http://dx.doi.org/10.12681/bgsg.11852.
Анотація:
Stress triggering must be incorporated into quantitative earthquake probability estimate, given that faults are interacted though their stress field. Using time dependent probability estimates this work aims at the evaluation of the occurrence probability of anticipated earthquakes near the city of Thessaloniki, an urban center of 1 million people located in northern Greece, conditional to the time elapsed since the last stronger event on each fault segment of the study area. A method that calculates the macroseismic epicenter and magnitude according to macroseismic intensities is used to improve the existing earthquake catalog (from AD 1600 - 2013 with M≥6.0) in order to compute new interevent and elapsed time values which form the basis for time-dependent probability estimates. To investigate the effects of stress transfer to seismic hazard, the probabilistic calculations presented here employ detailed models of coseismic stress associated with the 20 June 1978 M=6.5 Thessaloniki which is the latest destructive earthquake in the area in the instrumental era. The combined 2015-2045 regional Poisson probability of M≥6.0 earthquakes is ~35% the regional time-dependent probability varies from 0% to 15% and incorporation of stress transfer from 0% to 20% for each fault segment.
4
Seidou, O., B. Robert, C. Marche, J. Rousselle, and M. Lefebvre. "Construction probabiliste de scénarios d'apports à un réservoir." Canadian Journal of Civil Engineering 31, no. 1 (January 1, 2004): 146–54. http://dx.doi.org/10.1139/l03-108.
Анотація:
The behaviour of a hydric system depends on three factors : (i) the state of the installation, (ii) the operating rules, and (iii) the inflows. While the first two factors are (in theory) known to the manager, the third can only be estimated by means of more or less precise forecasts. A significant part of the risk, to which is subjected the system at a given time, is induced by the uncertainty in the future inflows. The evaluation of this uncertainty is therefore a first step in the incorporation of risk into management. Its evaluation is then a stage preliminary to the integration of the risk in management. A method of construction of inflow scenarios starting from an arbitrary date t of the year is developed in this paper. It uses a Markovian process formerly developed by the authors to model short-term uncertainty in stream flow. These scenarios, which are not equiprobable, are built to reproduce the statistical behaviour of the river or reservoir and have the shape of an event tree whose structure is defined by the user before application of the method. Two examples of application on two rivers located in Quebec, Canada, are presented.Key words: reservoir operation, previsions, inflows, risk, uncertainty.
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Zhang, Jianlong, Ye Zhu, Yingfeng Ji, Weiling Zhu, Rui Qu, Zhuoma Gongqiu, and Chaodi Xie. "Earthquake Risk Probability Evaluation for Najin Lhasa in Southern Tibet." Applied Sciences 12, no. 18 (September 19, 2022): 9394. http://dx.doi.org/10.3390/app12189394.
Анотація:
The probabilistic seismic hazard analysis (PSHA) method is effectively used in an earthquake risk probability evaluation in seismogenic regions with active faults. In this study, by focusing on the potential seismic source area in Najin Lhasa, southern Tibet, and by incorporating the PSHA method, we determined the seismic activity parameters and discussed the relationship of ground motion attenuation, the seismic hazard probability, and the horizontal bedrock ground motion acceleration peak value under different transcendence probabilities in this area. The calculation results show that the PSHA method divides the potential source area via specific tectonic scales and detailed tectonic markers, which reduces the scale of the potential source area and better reflects the uneven spatial distribution of seismic activity in the vicinity of Najin. The corrected attenuation relationship is also in line with the actual work requirements and is suitable for earthquake risk analysis. In addition, the major influences on the peak acceleration of ground motion in the study area are mainly in the potential source areas of Qushui (M7.5), Dangxiong (M8.5), and Kangma (M7.5). The peak horizontal ground motion acceleration (PGA) with a transcendence probability of 10% in 50 years is 185.9 cm/s2, and that with a transcendence probability of 2% in 50 years is 265.9 cm/s2.
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Zhou, Lintao, Qinge Wu, Hu Chen, and Tao Hu. "Interval fuzzy probability method for power transformer multiple fault diagnosis." Journal of Intelligent & Fuzzy Systems 41, no. 6 (December 16, 2021): 5957–68. http://dx.doi.org/10.3233/jifs-202083.
Анотація:
Accurately diagnosing power transformer faults is critical to improving the operational reliability of power systems. Although some researchers have made great efforts to improve the accuracy of transformer fault diagnosis, accurate diagnosis of multiple faults is still a difficult problem. In order to improve the accuracy of transformer multiple faults diagnosis, a multiple fault diagnosis method based on interval fuzzy probability is proposed. Different from the previous methods which provide single-value probability, this method use probability interval to represent the occurrence degree of various possible faults, which can objectively predict the potential faults that occurring in a transformer and provide a more reasonable explanation for the diagnosis results. In the proposed method, the interval fuzzy set is used to describe the evaluation of state variables and the interval fuzzy probability model based on interval weighted average is applied to integrate the fault information. The representative matrix of fault types based on fuzzy preference relationship is established to estimate the relative importance of each gas in the dissolved gases. The proposed method can provide the probability of probable faults in transformer, help engineers quickly determine the type and location of faults, and improve the accuracy of diagnosis and maintenance efficiency of transformer. The effectiveness of the method is verified with case studies.
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Kourd, Yahia, Dimitri Lefebvre, and Noureddine Guersi. "Neural Networks and Fault Probability Evaluation for Diagnosis Issues." Computational Intelligence and Neuroscience 2014 (2014): 1–15. http://dx.doi.org/10.1155/2014/370486.
Анотація:
This paper presents a new FDI technique for fault detection and isolation in unknown nonlinear systems. The objective of the research is to construct and analyze residuals by means of artificial intelligence and probabilistic methods. Artificial neural networks are first used for modeling issues. Neural networks models are designed for learning the fault-free and the faulty behaviors of the considered systems. Once the residuals generated, an evaluation using probabilistic criteria is applied to them to determine what is the most likely fault among a set of candidate faults. The study also includes a comparison between the contributions of these tools and their limitations, particularly through the establishment of quantitative indicators to assess their performance. According to the computation of a confidence factor, the proposed method is suitable to evaluate the reliability of the FDI decision. The approach is applied to detect and isolate 19 fault candidates in the DAMADICS benchmark. The results obtained with the proposed scheme are compared with the results obtained according to a usual thresholding method.
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Ju, Bu Seog, and WooYoung Jung. "Evaluation of Seismic Fragility of Weir Structures in South Korea." Mathematical Problems in Engineering 2015 (2015): 1–10. http://dx.doi.org/10.1155/2015/391569.
Анотація:
In order to reduce earthquake damage of multifunctional weir systems similar to a dam structure, this study focused on probabilistic seismic risk assessment of the weir structure using the fragility methodology based on Monte Carlo simulation (MCS), with emphasis on the uncertainties of the seismic ground motions in terms of near field induced pulse-like motions and far field faults. The 2D simple linear elastic plain strain finite element (FE) model including soil structure foundations using tie connection method in ABAQUS was developed to incorporate the uncertainty. In addition, five different limit states as safety criteria were defined for the seismic vulnerability of the weir system. As a consequence, the results obtained from multiple linear time history analyses revealed that the weir structure was more vulnerable to the tensile stress of the mass concrete in both near and far field ground motions specified earthquake hazard levels. In addition, the system subjected to near field motions was primarily more fragile than that under far field ground motions. On the other hand, the probability of failure due to the tensile stress at weir sill and stilling basin showed the similar trend in the overall peak ground acceleration levels.
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Bonachera Martin, Francisco Javier, and Robert J. Connor. "Load Combinations for the Evaluation of Redundancy in Steel Bridges." Transportation Research Record: Journal of the Transportation Research Board 2676, no. 4 (January 13, 2022): 524–37. http://dx.doi.org/10.1177/03611981211062162.
Анотація:
Over the past decade, there has been considerable interest in the development of quantitative analytical procedures to determine if a primary steel tension member (PSTM) is a fracture critical member (FCM). Traditionally, this designation has most often been arbitrarily determined based simply on the bridge geometry, for example, the number of girders in the cross section, rather than an evaluation of the bridge in the faulted state. Clearly, such a redundancy evaluation must address the loading scenarios concurrent with failure of the PSTM, the likelihood of the member failure, the acceptable probability of load exceeding resistance in the faulted state, and the application of vehicular live load models. This research was conducted to develop a load model and load combinations that are specific to evaluating the performance of a bridge in the event a steel member was to fracture. Specifically, two load combinations were developed to evaluate the strength of a steel bridge, one for the event in which the failure of a PSTM occurs, and another for a post-failure service period. The development adhered to the reliability-based principles and procedures applied in the calculation of load combinations currently used in bridge engineering to facilitate direct implementation and to ensure consistency with current steel bridge design and evaluation procedures contained in the AASHTO LRFD Bridge Design Specifications.
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Spiegel, Gerald, and Albrecht P. Stroele. "Realistic Fault Modeling and Extraction of Multiple Bridging and Break Faults." VLSI Design 7, no. 2 (January 1, 1998): 163–76. http://dx.doi.org/10.1155/1998/83615.
Анотація:
Fault sets that accurately describe physical failures are required for efficient pattern generation and fault coverage evaluation. The fault model presented in this paper uniquely describes all structural changes in the transistor net list that can be caused by spot defects, including bridging faults that connect more than two nets, break faults that break a net into more than two parts, and compound faults. The developed analysis method extracts the comprehensive set of realistic faults from the layout of CMOS ICs and for each fault computes the probability of occurrence. The results obtained by the tool REFLEX show that bridging faults connecting more than two nets account for a significant portion of all faults and cannot be neglected.
Дисертації з теми "Evaluation probabiliste des fautes":
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Alexandrescu, Marian-Dan. "Outils pour la simulation des fautes transitoires." Grenoble INPG, 2007. http://www.theses.fr/2007INPG0084.
Анотація:
Les événements singuliers proviennent de l'interaction d'une particule énergétique avec un circuit microélectronique. Ces perturbations peuvent modifier d'une manière imprévue le fonctionnement du circuit et introduire des fautes. La sensibilité des circuits augmentant à chaque nouvelle génération technologique, il devient nécessaire de disposer d'outils spécifiques pour la conception des circuits durcis face aux événements singuliers. Les travaux de cette thèse visent à étendre la compréhension de ces phénomènes et à proposer des outils CAO pour faciliter l'analyse de ces problèmes dans les circuits actuels. Nous avons développé des méthodologies pour l'analyse du comportement des cellules de la bibliothèque standard et des outils pour la simulation accélérée des fautes et pour l'évaluation probabiliste des effets singuliers. Les résultats fournis par ces outils vont permettre aux concepteurs d'évaluer et de choisir des méthodes adéquates pour améliorer la fiabilité des circuits intégrésSingle Events (SE) are produced by the interaction of charged particles with the transistors of a microelectronic circuit. These perturbations may alter the functioning of the circuit and cause logic faults and errors. As the sensitivity of circuits increases for each technological evolution, specific tools are needed for the design of hardened circuits. This thesis aims at furthering the comprehension of the phenomena and proposes EDA tools to help the analysis of these problems in today's ICs. We have developed methodologies for the characterization of the cells from the standard library and tools for accelerated fault simulation and probabilistic analysis of single events. The results provided by these tools allow the designer to correctly evaluate the sensitivity of his design and select the most adequate methods to improve the reliability of ICs
2
Kaâniche, Mohamed. "Evaluation de la sûreté de fonctionnement informatique. Fautes physiques, fautes de conception, malveillances." Habilitation à diriger des recherches, Institut National Polytechnique de Toulouse - INPT, 1999. http://tel.archives-ouvertes.fr/tel-00142168.
Анотація:
Les travaux résumés dans ce mémoire ont pour cadre la sûreté de fonctionnement des systèmes informatiques. Ils couvrent plusieurs aspects complémentaires, à la fois théoriques et expérimentaux, que nous avons groupés en quatre thèmes. Le premier thème traite de la définition de méthodes permettant de faciliter la construction et la validation de modèles complexes pour l'analyse et l'évaluation de la sûreté de fonctionnement. Deux approches sont considérées : les réseaux de Petri stochastiques généralisés et la simulation comportementale en présence de fautes. Le deuxième thème traite de la modélisation de la croissance de fiabilité pour évaluer l'évolution de la fiabilité et de la disponibilité des systèmes en tenant compte de l'élimination progressive des fautes de conception. Ces travaux sont complétés par la définition d'une méthode permettant de faciliter la mise en ¿uvre d'une étude de fiabilité de logiciel dans un contexte industriel. Le troisième thème concerne la définition et l'expérimentation d'une approche pour l'évaluation quantitative de la sécurité-confidentialité. Cette approche permet aux administrateurs des systèmes de suivre l'évolution de la sécurité opérationnelle quand des modifications, susceptibles d'introduire de nouvelles vulnérabilités, surviennent dans la configuration opérationnelle, les applications, le comportement des utilisateurs, etc. Enfin, le quatrième thème porte d'une part, sur l'élaboration d'un modèle de développement destiné à la production de systèmes sûrs de fonctionnement, et d'autre part, sur la définition de critères d'évaluation visant à obtenir une confiance justifiée dans l'aptitude des systèmes à satisfaire leurs exigences de sûreté de fonctionnement, en opération et jusqu'au retrait du service.
3
Carjaval, Moncada Claudio Andrés. "Evaluation probabiliste de la sécurité structurale des barrages-poids." Clermont-Ferrand 2, 2009. https://hal.archives-ouvertes.fr/tel-01298893.
Анотація:
L'objectif de la thèse est d'aborder l'évaluation de la sécurité structurale d'un barrage par une approche d'analyse de fiabilité. Notre travail est focalisé sur la catégorie des barrages-poids et propose des méthodes probabilistes pour la modélisation des propriétés des matériaux et des sollicitations. Pour la modélisation probabiliste des propriétés des matériaux, notre travail se focalise sur le corps des barrages-poids en béton. Les méthodes développées mettent en oeuvre : -l'analyse des dispersions des propriétés des matériaux aux différentes échelles spatiales, une démarche de fusion des informations disponibles et l'utilisation des relations physiques entre les résistances du béton des barrages. Concernant la modélisation probabiliste des sollicitations, nous focalisons notre recherche sur les actions hydrauliques, qui constituent les principales actions agissant sur les barrages. Les méthodes développées présentent deux principaux aspects innovants par rapport à une démarche d'ingénierie classique : la prise en compte de divers scénarios de crues et la prise en compte de la variabilité de la cote de la retenue avant l'occurence d'un événement hydrologique. La modélisation probabiliste de l'état-limite de résistance à l'effort tranchant, couplé avec l'ouverture de fissures est basée sur des méthodes classiques d'analyse de fiabilité, telles que les méthodes FORM/SORM et les méthodes de simulation de Monte-Carlo. L'application des méthodes développées est réalisée sur plusieurs cas de barrages en service. En terme de valorisation, nous proposons des recommandations et des outils opérationnels permattant la mise en oeuvre des méthodes développées
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Oboni, Franco. "Evaluation probabiliste des performances des pieux forés chargés axialement en tête /." [S.l.] : [s.n.], 1988. http://library.epfl.ch/theses/?nr=716.
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Koita, Abdourahmane. "Evaluation probabiliste de la dangerosité des trajectoires de véhicules en virages." Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2011. http://tel.archives-ouvertes.fr/tel-00626964.
Анотація:
Situé dans le contexte général de la sécurité routière, et plus particulièrement axé sur la sécurité des véhicules légers (VL) en virages, ce travail de thèse a pour objet de proposer une méthodologie fiabiliste de prédiction de trajectoires à risque, basée sur le traitement statistique et la modélisation probabiliste de trajectoires réelles de VL en virages. La première partie du travail concerne la construction de modèles probabilistes simples et robustes représentatifs des trajectoires réelles observées. Ces modèles sont des transformées de processus aléatoires scalaires normalisés du second ordre, faiblement stationnaires, ergodiques et non gaussiens, et permettent de décrire de façon réaliste la variabilité aléatoire observée du triptyque Véhicule-Infrastructure-Conducteur. Ils permettent aussi, par construction, de s'affranchir d'éventuelles difficultés dans l'alimentation des paramètres dominants qui les gouvernent. La seconde partie est consacrée au développement et à la mise en oeuvre d'une stratégie fiabiliste destinée à associer un niveau de risque à chaque trajectoire en entrée de virage. Basée sur l'emploi conjoint de méthodes probabilistes pour la modélisation des incertitudes, fiabilistes pour l'évaluation des niveaux de risque et statistiques pour la classification et le traitement des trajectoires, cette approche est une réponse réaliste au problème posé. De par sa conception et ses possibilités, la méthodologie fiabiliste proposée est une contribution significative au développement de procédures d'alerte destinées à réduire notablement le nombre d'accidents en virages.
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Joubert, Philippe. "Conception et evaluation d'une architecture multiprocesseur a memoire partagee tolerante aux fautes." Rennes 1, 1993. http://www.theses.fr/1993REN10004.
Анотація:
L'objectif de cette etude est la proposition d'une architecture multiprocesseur a memoire partagee tolerante aux fautes. Pour recuperer les defaillances de processus communiquant par memoire partagee, nous proposons un protocole de recuperation d'erreurs par retour arriere de type planifie qui prend en compte les communications au moyen d'une relation de dependance qui permet de definir dynamiquement l'ensemble des processus concernes par l'etablissement ou la restauration d'un point de recuperation. Nous proposons une mise en uvre de ce protocole dans laquelle la gestion des points de recuperation et des dependances est centralisee dans une memoire stable remplacant la memoire partagee de la machine. Cette technique evite d'avoir a concevoir d'autres composants specifiques. Nous evaluons ensuite les performances de notre proposition par simulation. Du fait des mecanismes de recuperation d'erreurs, une certaine degradation des performances par rapport a une architecture non tolerante aux fautes est inevitable. Cependant, les simulations montrent que cette degradation reste dans des limites raisonnables. Les simulations montrent aussi que notre proposition obtient des performances superieures a celles des autres architectures tolerantes aux fautes du meme type
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Kameni, Ngassa Christiane. "Décodeurs LDPC opérant sur des circuits à comportement probabiliste : limites théoriques et évaluation pratique de la capacité de correction." Thesis, Cergy-Pontoise, 2014. http://www.theses.fr/2014CERG0735/document.
Анотація:
Ces dernières années ont vu naitre un intérêt grandissant pour les décodeurs correcteurs d'erreurs opérant sur des circuits non fiables. En effet, la miniaturisation croissante des composants électroniques ainsi l'échelonnage agressif de la tension d'alimentation ont pour conséquence la diminution de la fiabilité des systèmes. Par conséquent, les futures générations de circuits électroniques seront intrinsèquement non fiables. En outre, les décodeurs correcteurs d'erreurs sont indispensables non seulement pour assurer une transmission fiable de l'information mais aussi pour concevoir des systèmes de stockage performants.Nous nous intéressons, dans cette thèse, plus particulièrement aux décodeurs à précision finie Min-Sum (MS), Self-Corrected Min-Sum (SCMS) et Stochastiques.Nous commençons par effectuer une analyse statistique du décodeur Min-Sum opérant sur des circuits à comportement probabiliste. Pour ce faire nous introduisons des modèles d'erreurs probabilistes pour les composants logiques et les opérateurs arithmétiques du décodeur et étudions leurs propriétés de symétrie. Puis nous effectuions une analyse asymptotique rigoureuse et en déduisons les équations d'évolution de densité du décodeur Min-Sum bruité. Nous mettons ainsi en évidence l'effet positif, dans certains cas, du bruit issu du circuit sur la capacité de correction du décodeur. Nous révélons ensuite l'existence d'un phénomène de seuil particulier que nous nommons seuil fonctionnel. Ce dernier peut être considéré comme la généralisation du seuil classique pour les décodeurs non fiables. Nous corroborons ensuite les résultats asymptotiques par des simulations Monte-Carlo.Nous implémentons des décodeurs LDPC bruités pour plusieurs paramètres de bruit et montrons que les décodeurs LDPC bruité ont des résultats très proches de ceux des décodeurs non bruités. Nous pouvons par conséquent considérer le circuit d'autocorrection comme un patch bruité appliqué au décodeur MS bruité afin d'améliorer la robustesse du décodeur face au bruit issu des composants non fiables. Nous évaluons par railleurs l'impact de l'ordonnancement et montrons qu'un ordonnancement série dégrade fortement la robustesse des décodeurs bruités MS et SCMS qui ne parviennent plus à atteindre une capacité de correction acceptable.Pour finir nous étudions les performances des décodeurs stochastiques pourvus de mémoires d'arêtes et opérant sur des circuits non fiables. Nous proposons deux modèles d'erreurs décrivant le comportement probabiliste des composants du décodeur. Nous montrons que, dans certains cas, le bruit issu du circuit non fiable permet de réduire le plancher d'erreur. Nous en déduisons alors que le décodeur stochastique est intrinsèquement tolérant aux fautesOver the past few years, there has been an increasing interest in error correction decoders built out of unreliable components. Indeed, it is widely accepted that future generation of electronic circuit will be inherently unreliable, due to the increase in density integration and aggressive voltage scaling. Furthermore, error correction decoders play a crucial role both in reliable transmission of information and in the design of reliable storage systems. It is then important to investigate the robustness of error correction decoders in presence of hardware noise.In this thesis we focus on LDPC decoders built out of unreliable computing units. We consider three types of LDPC decoders: the finite-precision Min-Sum (MS) decoder, the Self-Corrected Min-Sum (SCMS) decoder and the Stochastic decoder.We begin our study by the statistical analysis of the finite-precision Min-Sum decoder with probabilistic components. To this end, we first introduce probabilistic models for the arithmetic and logic units of the decoder and discuss their symmetry properties. We conduct a thorough asymptotic analysis and derive density evolution equations for the noisy Min-Sum decoder. We highlight that in some particular cases, the noise introduced by the device can increase the correction capacity of the noisy Min-Sum with respect to the noiseless decoder. We also reveal the existence of a specific threshold phenomenon, referred to as functional threshold, which can be viewed as the generalization of the threshold definition for noisy decoders. We then corroborate the asymptotic results through Monte-Carlo simulations.Since density evolution cannot be defined for decoders with memory, the analysis of noisy Self-corrected Min-Sum decoders and noisy Stochastic decoders was restricted to Monte-Carlo simulations.We emulate the noisy SCMS decoders with various noise parameters and show that noisy SCMS decoders perform close to the noiseless SCMS decoder for a wide range of noise parameters. Therefore, one can think of the self-correction circuit as a noisy patch applied to the noisy MS decoder, in order to improve its robustness to hardware defect. We also evaluate the impact of the decoder scheduling on the robustness of the noisy MS and SCMS decoders and show that when the serial scheduling is used neither the noisy MS decoder nor the noisy SCMS decoder can provide acceptable error correction.Finally, we investigate the performance of stochastic decoders with edge-memories in presence of hardware noise. We propose two error models for the noisy components. We show that in some cases, the hardware noise can be used to lower the error floor of the decoder meaning that stochastic decoders have an inherent fault tolerant capability
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QUENNESSON, CYRIL. "Evaluation de circuits vlsi autocontroles prenant en compte un modele de fautes multiples." Paris 6, 1997. http://www.theses.fr/1997PA066163.
Анотація:
Devant la necessite de circonvenir les consequences de phenomenes physiques (flash ionisant, foudre, courants de commutation,. . . ) generant de fortes perturbations transitoires au sein des circuits integres, nous nous sommes fixe pour objectif de montrer la faisabilite de systemes efficaces de test en ligne, dans le cas de fautes multiples presentes dans le circuit. Les methodes actuelles demontrent, de facon formelle, l'efficacite d'un autocontrole, mais ne peuvent etre appliquees si l'on adopte un modele de fautes multiples. Nous avons donc developpe une methode de mesure de taux d'integrite utilisant un tel modele. Cette methode, originale, repose sur la simulation et l'introduction de defectuosites dans les circuits testes. Elle fournit une mesure statistique de l'efficacite des systemes implantes. L'approche est interessante car elle permet de realiser simplement une analyse approfondie de n'importe quel type d'autocontrole. En outre, ses fondements sont tres generaux et autorisent tout modele de faute. Nous avons developpe cati (calcul de taux d'integrite), outil de cao correspondant. Grace a plusieurs etudes realisees a l'aide de ce logiciel, nous montrons la specificite du probleme des fautes multiples. Nous montrons egalement qu'il est possible d'obtenir d'excellents resultats avec un modele de fautes multiples, en modifiant et adaptant les architectures existantes dediees a l'autocontrole. Afin de demontrer experimentatlement la faisabilite d'un autocontrole performant selon un modele de fautes multiples, deux circuits de demonstration ont ete realises. Ils comportent dix types differents d'autocontrole. Leur analyse par cati et les resultats des experimentations effectuees permettent de valider notre methode de mesure de taux d'integrite et de montrer qu'il est possible de concevoir un autocontrole performant en presence d'erreurs multiples.
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GEFFLAUT, ALAIN. "Proposition et evaluation d'une architecture multiprocesseur extensible a memoire partagee tolerante aux fautes." Rennes 1, 1995. http://www.theses.fr/1995REN10034.
Анотація:
L'objectif de cette etude est la proposition d'une architecture multiprocesseur extensible a memoire partagee tolerante aux fautes. Pour ameliorer leur efficacite, les architectures extensibles a memoire partagee utilisent des caches maintenus coherents a l'aide de protocoles de coherence. Les architectures coma (cache only memory architectures) etendent ce principe en utilisant les memoires standard comme des caches de grande dimension. D'un autre cote, la recuperation arriere est une technique de tolerance aux fautes qui necessite la conservation et la replication de donnees de recuperation. Le but de cette etude est d'utiliser les mecanismes de replication de donnees offerts par les architectures coma pour assurer la redondance necessaire a l'implementation d'une technique de recuperation arriere. Nous proposons un protocole de coherence etendu qui gere de facon transparente les donnees courantes et les donnees de recuperation. Ce protocole permet de tolerer les defaillances des nuds de l'architecture en limitant le materiel specifique, grace a l'utilisation des memoires standard pour stocker les donnees courantes et les donnees de recuperation. Une evaluation du protocole par simulation montre que l'utilisation des mecanismes de replication de donnees et des memoires pour la gestion des donnees de recuperation, limite la degradation de performance tout en conservant l'extensibilite de l'architecture
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Sopena, Julien. "Algorithmes d'exclusion mutuelle : tolérance aux fautes et adaptation aux grilles." Paris 6, 2008. http://www.theses.fr/2008PA066665.
Книги з теми "Evaluation probabiliste des fautes":
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Koukou, Adamou. L'education au Niger: Fautes d'orthographe et échecs scolaires. Niger: SONIDEP, 2008.
Частини книг з теми "Evaluation probabiliste des fautes":
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Martinello, Magnos, Mohamed Kaâniche, and Karama Kanoun. "Performability Evaluation of Web-Based Services." In Performance and Dependability in Service Computing, 243–64. IGI Global, 2012. http://dx.doi.org/10.4018/978-1-60960-794-4.ch011.
Анотація:
The joint evaluation of performance and dependability in a unique approach leads to the notion of performability which usually combines different analytical modeling formalisms (Markov chains, queueing models, etc.) for assessing systems behaviors in the presence of faults. This chapter presents a systematic modeling approach allowing designers of web-based services to evaluate the performability of the service provided to the users. We have developed a multi-level modeling framework for analyzing the user perceived performability. Multiple sources of service unavailability are taken into account, particularly i) hardware and software failures affecting the servers, and ii) performance degradation due to e.g. overload of servers and probability of loss. The main concepts and the feasibility of the proposed framework are illustrated using a web-based travel agency. Various analytical models and sensitivity studies are presented considering different assumptions with respect to users profiles, architecture, faults, recovery strategies, and traffic characteristics.
Тези доповідей конференцій з теми "Evaluation probabiliste des fautes":
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Abdollahzadeh, Hamed, and Mostafa Jazaeri. "Probabilistic evaluation of impacts of high-resistance faults on digital distance relays." In 2016 18th Mediterranean Electrotechnical Conference (MELECON). IEEE, 2016. http://dx.doi.org/10.1109/melcon.2016.7495354.
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Gomes, E. E. B., and P. Pilidis. "Gas Turbine Life Cycle Assessment and Preliminary Risk Analysis." In ASME Turbo Expo 2007: Power for Land, Sea, and Air. ASMEDC, 2007. http://dx.doi.org/10.1115/gt2007-27972.
Анотація:
The prediction of possible faults in gas turbines power systems can have a great impact on the maintenance program efficiency as they can allow generators optimize generation schedule and increase profits. This study provides an evaluation of the gas turbine life time during its operation over a life cycle and evaluates the risk involved in such assessment. A mathematical model was developed to calculate the principal variables that take part in life cycle assessment: time, temperature and stress loads. Because of stochastic nature of the failure mechanisms involved in life cycle assessment of gas turbines, a probabilistic risk analysis was carried out to properly evaluate the uncertainty involved. The work conditions of the gas turbine identify the mechanical failure mechanism that rules a gas turbine life. The risk analysis algorithm produces the expected window time in which the turbine blade is expected to failure and its respective probability. The gas turbine life cycle assessment and risk analysis described in this investigation are strategic and powerful tools for optimization of gas turbines power systems.
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Breese, John S., Eric J. Horvitz, Mark A. Peot, Rodney Gay, and George H. Quentin. "Automated Decision-Analytic Diagnosis of Thermal Performance in Gas Turbines." In ASME 1992 International Gas Turbine and Aeroengine Congress and Exposition. American Society of Mechanical Engineers, 1992. http://dx.doi.org/10.1115/92-gt-399.
Анотація:
We have developed an expert system for diagnosis of efficiency problems for large gas turbines. The system relies on a model-based approach that combines an expert’s probabilistic assessments with statistical data and thermodynamic analysis. The system employs a causal probabilistic graph, called a belief network, to update the likelihoods of alternative faults given information about diverse classes of information. In response to any subset of findings or reported observations, the system suggests the most cost-effective tests to perform to determine the source of a performance problem. We discuss the decision-analytic methodology that underlies the development of the system and present results of an initial version of the system. Finally, we discuss future planned development and evaluation, toward the ultimate goal of applying the system in the day-to-day maintenance of gas-turbine power plants.
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Naderi, E., N. Meskin, and K. Khorasani. "Nonlinear Fault Diagnosis of Jet Engines by Using a Multiple Model-Based Approach." In ASME 2011 Turbo Expo: Turbine Technical Conference and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/gt2011-45143.
Анотація:
In this paper, a nonlinear fault detection and isolation (FDI) scheme that is based on the concept of multiple model (MM) approach is proposed for jet engines. A modular and a hierarchical architecture is proposed which enables the detection and isolation of both single as well as concurrent permanent faults in the engine. A set of nonlinear models of the jet engine in which compressor and turbine maps are used for performance calculations corresponding to various operating modes of the engine (namely, healthy and different fault modes) is obtained. Using the multiple model approach the probabilities corresponding to the engine modes of operation are first generated. The current operating mode of the system is then detected based on evaluating the maximum probability criteria. The performance of our proposed multiple model FDI scheme is evaluated by implementing both the Extended Kalman Filter (EKF) and the Unscented Kalman Filter (UKF). Simulation results presented demonstrate the effectiveness of our proposed multiple model FDI algorithm for both structural and actuator faults in the jet engine.
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Kramer, Stefan, Peter Raab, Jurgen Mottok, and Stanislav Racek. "Comparison of Enhanced Markov Models and Discrete Event Simulation: For Evaluation of Probabilistic Faults in Safety-Critical Real-Time Task Sets." In 2014 17th Euromicro Conference on Digital System Design (DSD). IEEE, 2014. http://dx.doi.org/10.1109/dsd.2014.42.
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Meskin, N., E. Naderi, and K. Khorasani. "Fault Diagnosis of Jet Engines by Using a Multiple Model-Based Approach." In ASME Turbo Expo 2010: Power for Land, Sea, and Air. ASMEDC, 2010. http://dx.doi.org/10.1115/gt2010-23442.
Анотація:
In this paper, a novel real-time fault detection and isolation (FDI) scheme that is based on the concept of multiple model approach is proposed for jet engines. A modular and a hierarchical architecture is proposed which enables the detection and isolation of both single as well as permanent concurrent faults in the engine. The nonlinear dynamics of the jet engine is linearized in which compressors and turbines maps are used for performance calculations and a set of linear models corresponding to various operating modes of the engine (namely healthy and different fault modes) at each operating point is obtained. Using the multiple model approach the probabilities corresponding to each operating point of the engine are generated and the current operating mode of the system is detected based on evaluating the maximum probability criteria. It is shown that the proposed methodology is also robust to the failure of pressure and temperature sensors and extensive levels of noise outliers in the sensor measurements. Simulation results presented demonstrate the effectiveness of our proposed multiple model FDI algorithm for both structural faults and actuator fault in the jet engine.
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Lipowsky, Holger, Stephan Staudacher, Daniel Nagy, and Michael Bauer. "Gas Turbine Fault Diagnostics Using a Fusion of Least Squares Estimations and Fuzzy Logic Rules." In ASME Turbo Expo 2008: Power for Land, Sea, and Air. ASMEDC, 2008. http://dx.doi.org/10.1115/gt2008-50190.
Анотація:
This paper presents a method to improve the process of gas turbine diagnosis in case of a single fault event by calculating both deviations of performance parameters from their nominal values and fault probabilities. The approach is based on a thermodynamic model of the monitored gas turbine that is used to generate an Influence-Coefficient-Matrix (ICM) describing the gas turbine’s behaviour at the desired operating point in a linearised form. The ICM is used to calculate deviations of performance parameters by least squares estimation. As it is not known a priori how many components are affected by a fault, the ICM is evaluated with respect to all possible fault numbers and combinations leading to sets of analyses. The nature of least squares estimation method limits the number of detectable faults (and thus the number of analyses sets) to the number of available measurements. In a second step a fuzzy logic system is applied to calculate the probability of each performance parameter to be actually affected by the fault. This is done by applying fuzzy logic rules taking into account the frequency and the mean deviation of every performance parameter within every set of analyses. The third and last step is to sum the probabilities over all sets in order to obtain a global probability for every performance parameter. The proposed technique has been applied to several simulated test cases with encouraging results. The main benefit of the technique is that the diagnostic result contains both magnitude and probability of the deviations of performance parameters. Furthermore, robustness in terms of measurement noise is achieved by using a statistical evaluation method.
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Zhu, Guixia, Tianmi Zhou, Yugang Qian, Chongchong Liu, and Hongxing Lu. "Reliability Assessment of NPP System for Risk Management Based on an Information Reasoning Methodology." In 2020 International Conference on Nuclear Engineering collocated with the ASME 2020 Power Conference. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/icone2020-16482.
Анотація:
Abstract Risk management (RM) is an effective means of safety assessment and reliability management of nuclear power plant (NPP). During the operation of NPP, the main contents of RM work are as follows: 1. Real-time reliability assessment of NPP system, and evaluate NPP risk, so as to ensure that the NPP system can complete the specified functions to deal with the consequences of system failure. 2. Complete the diagnosis and mitigation of abnormal faults, so as to ensure that the NPP system can return to a safe state as soon as possible in the case of abnormal operation of NPP. With the continuous improvement of the requirements of online RM, LPSA (Living PSA) technology, as an effective tool of RM, has been developed and provides more powerful support for the safe operation of NPP. In order to evaluate the reliability of NPP system in real time, LPSA model needs to be updated to match the state of the system. Most of the existing LPSA model updating techniques are based on the premise that the system information is completely knowable and the information is accurate. However, in the process of NPP operation, the accessibility of system information and the accuracy of information are difficult to meet the requirements of updating the existing LPSA model. How to update the LPSA model in the case of incomplete and inaccurate information is one of the difficulties in the application of online LPSA technology. Especially when the NPP is in abnormal conditions, it is more urgent for operators to obtain correct system information in real time to recognize the available state of the plant system. In fact, the required system information needs to be obtained by the operator through his or her cognitive behavior process, such as the fault diagnosis process. At the same time, this information can be used to help operators complete the diagnosis of system status and the evaluation of system reliability. In this study, an information reasoning method is proposed to evaluate the probability of various failure modes under the information known to the operator through the modeling and analysis of the cognitive behavior process of the operator. The method can assist the operator to make the correct fault judgment to complete the fault diagnosis and fault mitigation. In addition, the information obtained by the operator in the process of cognitive behavior, and the results of information reasoning can be used to update the LPSA model in real time, so as to obtain the real-time reliability evaluation results of the NPP system.