Diagnostic hors-ligne à base de modèles : approche multi-modèle pour la génération automatique de séquences de tests. Application au domaine de l'automobile

Le travail de cette thèse s'intéresse au problème du diagnostic débarqué dans le domaine automobile. Il a consisté à proposer et à mettre en œuvre une méthode opérationnelle à base de modèles qui détermine les meilleures séquences de tests que doit réaliser le garagiste afin de localiser un composant défaillant sur un véhicule. Nous proposons une approche de représentation multi-modèle des systèmes mécatronique afin de prendre en compte la complexité fonctionnelle des architectures embarquées actuelles et de relier des symptômes fonctionnels de haut niveau à un ensemble de défauts portant sur des composants matériels et logiciels. Le séquencement des tests est réalisé à partir d'un critère du prochain meilleur test. Cette stratégie interactive laisse l'initiative à l'opérateur humain d'accepter ou de refuser le test proposé. Un prototype logiciel a été développé et testé avec succès sur la fonction essuyage arrière de véhicules réels. Cette thèse a été réalisée dans le cadre d'une convention CIFRE entre le LAAS-CNRS et la société ACTIA ainsi que dans le cadre du Laboratoire Commun Autodiag (LAAS, IRIT, ACTIA) dont l'objectif est de développer de nouvelles méthodes de diagnostic pour le domaine automobile.This thesis deals with the problem of off-board diagnosis in the automotive domain. The work has consisted in proposing and implementing an operational model based approach that determines the best sequences of tests to be performed by the garage mechanic to localise a faulty component on a vehicle. A multi-model approach is proposed for the description of mechatronic systems, which allows us to handle the functional complexity of embedded systems and to match functional symptoms with a set of faults on hardware / software components. The test sequencing problem is approached along a next best test strategy based on a local heuristic. This strategy enables an interactive diagnostic session, allowing more flexibility and leaving with the human operator the initiative to accept or reject the proposed test. A software prototype has been developed and tested on the rear wiper system of real vehicles. This thesis, supported by a CIFRE grant, is the result of collaboration between the company ACTIA and the research center LAAS-CNRS in the framework of the common laboratory Autodiag (LAAS, IRIT, ACTIA) which aims at developing new methods for diagnosis in the automotive domain

Membre du comité d'organisation du Séminaire de lancement du projet NatAdGES

National audienc

Factors predictive of macrosomia in pregnancies with a positive oral glucose challenge test: importance of fasting plasma glucose.

The study aimed to determine the factors associated with fetal macrosomia following a positive oral glucose challenge test (OGCT). In this retrospective single-centre study of 1268 pregnancies with positive 50-g OGCTs (plasma glucose≥130mg/dL, or 7.2mmol/L), gestational diabetes mellitus (GDM) was defined as fasting plasma glucose (FPG)≥95mg/dL (5.3mmol/L) and/or postprandial glucose (PPG)≥120mg/dL (6.7mmol/L). In GDM pregnancies, the odds ratios adjusted for confounders (age, BMI, ethnicity, parity and weight gain) were 2.02 for macrosomia (Z score≥1.28) and 2.62 for severe macrosomia (Z score≥1.88). For each 10-mg/dL increase in FPG, the mean birth-weight increase was 60g. Macrosomia risk did not differ between GDM patients with normal FPG (<95mg/dL, or 5.3mmol/L) and non-diabetics, but increased significantly in cases of FPG≥95mg/dL and regardless of the level of PPG. In our study population, birth-weight and macrosomia risk were strongly correlated with FPG, suggesting that it is a simple and efficient marker for the risk of macrosomia

MR imaging of the heart in patients after myocardial infarction: Effect of increasing intersection gap on measurements of left ventricular volume, ejection fraction, and wall thickness

International audienceAbstract: PURPOSE: To determine the extent to which the number of planes imaged at magnetic resonance (MR) imaging could be reduced without modifying the volume and thickness of the left ventricle. MATERIALS AND METHODS: Sixty-one patients were examined after a myocardial infarction. The whole left ventricle was imaged by using 5-mm contiguous breath-hold cine MR short-axis sections with no gap (SA(ng)) (two-dimensional fast low-angle shot sequence, 9/4.8 [repetition time msec/echo time msec]). The effect of omitting in two (short-axis sections with 5-mm gap [SA(5mm)]) or two sections in three(short-axis sections with 10-mm gap [SA(10mm)]) was studied. RESULTS: In the comparison of SA(5mm) or SA(10mm) with respect to the reference SA(ng), standard Error of the estimate (SEE) for the diastolic volume did not exceed the 6.1% interobserver SEE, and the SEE for the ejection fraction remained lower than the 3% interobserver SEE. The measured wall thickness was not affected. In addition, six simple geometric models were compared with SA(ng) and yielded an SEE of 9.5%-28.1% for the diastolic volume and 3.8%-13.3% for the ejection fraction. CONCLUSION: In the study of left ventricles with heterogeneous contractility, short-axis imaging is more accurate than geometric modeling and permits wall thickness measurements when an intersection gap of 5 or 10 mm is used

Indications de l'IRM cardiaque.

International audienc

Fractional Flow Reserve to Guide Treatment of Patients With Multivessel Coronary Artery Disease

International audienc