1,989 research outputs found
Piet F. M. Fontaine : A l'occasion du 11 avril 1991
No full textPiet F. M. Fontaine : A l'occasion du 11 avril 199
Sensitivity of the virtual fields method to noisy data
No full textThis paper deals with the application of the virtual fields method (VFM) to the identification of constants governing anisotropic constitutive equations. After a short recalling of the main features of the VFM, its sensitivity to noisy data is addressed. The study focuses on the random component of the noise which always adds to the actual fields in experimental full-field measurements. The uncertainty of the identified constants due to this random component is derived analytically. The obtained closed-form expression is set as a criterion for grading virtual fields. The least sensitivity to noise leads to the best identification. The grading procedure is implemented directly in the VFM algorithm, providing systematically the virtual field which minimizes the sensitivity to random noises. Examples are provided for validating the approach with numerically simulated noisy data. Finally, the grading procedure is applied for adjusting the geometry which leads to an optimal use of the three-point bending test for identifying the elastic constants of a composite material. It shows that the criterion sensitivity to noise characterizes quantitatively the identifiability of one or several parameters. Future applications appear quite promising within the design of novel test methods for composites using the VFM.<br/
Huitième séminaire de l'A. F. P. M. A. à Valenciennes, 29-30 avril 1984
No full textAllag Claudine. Huitième séminaire de l'A. F. P. M. A. à Valenciennes, 29-30 avril 1984. In: Revue du Nord, tome 67, n°264, Janvier-mars 1985. pp. 7-8
Angers, sous la direction de F. Lebrun, avec la collaboration de J. Avril, J.-M. Bienvenu, S. Chassagne, F. Laplanche, J.-L. Marais
No full textLe Brun Jacques. Angers, sous la direction de F. Lebrun, avec la collaboration de J. Avril, J.-M. Bienvenu, S. Chassagne, F. Laplanche, J.-L. Marais. In: Revue de l'histoire des religions, tome 200, n°2, 1983. pp. 234-235
F. M. Cornford. The Laws of motion in ancient thougt
No full textBréhier Émile. F. M. Cornford. The Laws of motion in ancient thougt. In: Revue des Études Grecques, tome 46, fascicule 215-216, Avril-juin 1933. pp. 252-253
F. M. Cornford. The Laws of motion in ancient thougt
No full textBréhier Émile. F. M. Cornford. The Laws of motion in ancient thougt. In: Revue des Études Grecques, tome 46, fascicule 215-216, Avril-juin 1933. pp. 252-253
Machine learning and reduced order modelling for the simulation of braided stent deployment
No full textEndoluminal reconstruction using flow diverters represents a novel paradigm for the minimally invasive treatment of intracranial aneurysms. The configuration assumed by these very dense braided stents once deployed within the parent vessel is not easily predictable and medical volumetric images alone may be insufficient to plan the treatment satisfactorily. Therefore, here we propose a fast and accurate machine learning and reduced order modelling framework, based on finite element simulations, to assist practitioners in the planning and interventional stages. It consists of a first classification step to determine a priori whether a simulation will be successful (good conformity between stent and vessel) or not from a clinical perspective, followed by a regression step that provides an approximated solution of the deployed stent configuration. The latter is achieved using a non-intrusive reduced order modelling scheme that combines the proper orthogonal decomposition algorithm and Gaussian process regression. The workflow was validated on an idealized intracranial artery with a saccular aneurysm and the effect of six geometrical and surgical parameters on the outcome of stent deployment was studied. We trained six machine learning models on a dataset of varying size and obtained classifiers with up to 95% accuracy in predicting the deployment outcome. The support vector machine model outperformed the others when considering a small dataset of 50 training cases, with an accuracy of 93% and a specificity of 97%. On the other hand, real-time predictions of the stent deployed configuration were achieved with an average validation error between predicted and high-fidelity results never greater than the spatial resolution of 3D rotational angiography, the imaging technique with the best spatial resolution (0.15 mm). Such accurate predictions can be reached even with a small database of 47 simulations: by increasing the training simulations to 147, the average prediction error is reduced to 0.07 mm. These results are promising as they demonstrate the ability of these techniques to achieve simulations within a few milliseconds while retaining the mechanical realism and predictability of the stent deployed configuration
Ciceri (M. F.), Marchand (B.), Rimbert (S.). -Introduction à l'analyse de l'espace.
No full textBomer Bernard. Ciceri (M. F.), Marchand (B.), Rimbert (S.). -Introduction à l'analyse de l'espace. . In: Norois, n°102, Avril-Juin 1979. pp. 285-287
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