30 research outputs found
Characterisation of the fouling of an ultrafiltration polyethersulfone membrane fouled by an emulsion modelling lipids issued from Microalgae
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Prise en compte des covariables temporelles dans la modélisation des événements récurrents
L'étude porte sur la modélisation des événements récurrents d'un système réparable avec maintenances imparfaites, fondée sur la généralisation du modèle NHPP. L'effet des maintenances sur l'intensité est pris en compte par le nombre de défaillances précédentes. L'introduction des covariables dépendantes du temps dans le modèle a été détaillée ainsi que l'algorithme de simulation des données. L'application à la modélisation des défaillances d'un réseau d'eau est présentée. / The study aims at modelling recurrent events of a repairable system with imperfect maintenances based on the generalisation of the NHPP model. The effect of the maintenances on the intensity is taken into account by considering the number of previous failures. The introduction of time-dependent covariates into the model is detailed as well as the algorithm of data simulation. The application to failure modelling of the water distribution system is presented
Prise en compte des covariables temporelles dans la modélisation des événements récurrents
L'étude porte sur la modélisation des événements récurrents d'un système réparable avec maintenances imparfaites, fondée sur la généralisation du modèle NHPP. L'effet des maintenances sur l'intensité est pris en compte par le nombre de défaillances précédentes. L'introduction des covariables dépendantes du temps dans le modèle a été détaillée ainsi que l'algorithme de simulation des données. L'application à la modélisation des défaillances d'un réseau d'eau est présentée. / The study aims at modelling recurrent events of a repairable system with imperfect maintenances based on the generalisation of the NHPP model. The effect of the maintenances on the intensity is taken into account by considering the number of previous failures. The introduction of time-dependent covariates into the model is detailed as well as the algorithm of data simulation. The application to failure modelling of the water distribution system is presented
Modeling failures of repairable systems under "worse than old" assumption
The objective of the work is to model the failure process of a repairable system under "worse than old", or harmful repairs, assumption. The proposed model is founded on the counting process probabilistic approach and interprets harmful repairs as the accumulation of failures on the same system. The explicit form of likelihood function is given. Fixed and time-varying covariates are taken into account. Monte-Carlo simulations are carried out to asses the quality of the MLE. The method of data generation is detailed
Modeling failures of repairable systems under "worse than old" assumption
The objective of the work is to model the failure process of a repairable system under "worse than old", or harmful repairs, assumption. The proposed model is founded on the counting process probabilistic approach and interprets harmful repairs as the accumulation of failures on the same system. The explicit form of likelihood function is given. Fixed and time-varying covariates are taken into account. Monte-Carlo simulations are carried out to asses the quality of the MLE. The method of data generation is detailed
Consumption estimation with a partial automatic meter reading deployment
Automatic water meter reading (AMR) is now the best kind of technology to supply real time information on water consumption. Complete equipment of a district metered area enables the assessment of the total consumption of a finite size population, for a time scale sometimes as short as an hour. However, its cost for generalization can generate high capital expenditures (CAPEX), unaffordable for the utility, in which case sampling techniques have to be set up. With the purpose of total consumption estimation, this article describes standard methods of survey techniques applied to water networks and proposes a methodology for implementation of an operational sample. The methodology, which includes some constraints on the estimator precision, proposes a smart AMR equipment plan of the population, while reducing CAPEX. Finally, estimation of the total consumption, in addition to the knowledge of supplied volume, enables more accurate loss assessment and potential detection of new leaks