Optimal Data Split Methodology for Model Validation

The decision to incorporate cross-validation into validation processes of mathematical models raises an immediate question - how should one partition the data into calibration and validation sets? We answer this question systematically: we present an algorithm to find the optimal partition of the data subject to certain constraints. While doing this, we address two critical issues: 1) that the model be evaluated with respect to predictions of a given quantity of interest and its ability to reproduce the data, and 2) that the model be highly challenged by the validation set, assuming it is properly informed by the calibration set. This framework also relies on the interaction between the experimentalist and/or modeler, who understand the physical system and the limitations of the model; the decision-maker, who understands and can quantify the cost of model failure; and the computational scientists, who strive to determine if the model satisfies both the modeler's and decision maker's requirements. We also note that our framework is quite general, and may be applied to a wide range of problems. Here, we illustrate it through a specific example involving a data reduction model for an ICCD camera from a shock-tube experiment located at the NASA Ames Research Center (ARC).Comment: Submitted to International Conference on Modeling, Simulation and Control 2011 (ICMSC'11), San Francisco, USA, 19-21 October, 201

QUOTATION FOR THE VALUE ADDED ASSESSMENT DURING PRODUCT DEVELOPMENT AND PRODUCTION PROCESSES

This communication is based on an original approach linking economical factors to technical and methodological ones. This work is applied to the decision process for mix production. This approach is relevant for costing driving systems. The main interesting point is that the quotation factors (linked to time indicators for each step of the industrial process) allow the complete evaluation and control of, on the one hand, the global balance of the company for a six-month period and, on the other hand, the reference values for each step of the process cycle of the parts. This approach is based on a complete numerical traceability and control of the processes (design and manufacturing of the parts and tools, mass production). This is possible due to numerical models and to feedback loops for cost indicator analysis at design and production levels. Quotation is also the base for the design requirements and for the choice and the configuration of the production process. The reference values of the quotation generate the base reference parameters of the process steps and operations. The traceability of real values (real time consuming, real consumable) is mainly used for a statistic feedback to the quotation application. The industrial environment is a steel sand casting company with a wide mix product and the application concerns both design and manufacturing. The production system is fully automated and integrates different products at the same time.design and production, cost driving system, numerical traceability

Quantum Reflection of Antihydrogen in the GBAR Experiment

In the GBAR experiment, cold antihydrogen atoms will be left to fall on an annihilation plate with the aim of measuring the gravitational acceleration of antimatter. Here, we study the quantum reflection of these antiatoms due to the Casimir-Polder potential above the plate. We give realistic estimates of the potential and quantum reflection amplitudes, taking into account the specificities of antihydrogen and the optical properties of the plate. We find that quantum reflection is enhanced for weaker potentials, for example above thin slabs, graphene and nanoporous media.Comment: Workshop on Antimatter and Gravity Bern 2013 Proceeding

Maîtriser les déluges de données hétérogènes

Le traitement automatique des langues fait de plus en plus appel à de volumineux corpus textuels pour l'acquisition des connaissances. L'obstacle actuel n'est plus la disponibilité de corpus, ni même leur taille, mais l'hétérogénéité des données qui sont rassemblées sous ce nom. Dans cet article, nous examinons l'hétérogénéité que manifestent les articles du Monde quand on les regroupe selon les rubriques de la rédaction du journal. Les conséquences d'une telle hétérogénéité pour l'étiquetage et le parsage sont soulignées. Partant de ce constat, nous définissons la notion de "profilage de corpus" par le biais d'outils permettant d'évaluer l'homogénéité d'un corpus (sur-emploi du vocabulaire, de catégories morpho-syntaxiques, ou de patrons) et l'utilisation qui peut en être faite

Profilage de textes : un cadre de travail et une expérience

International audienceLe recours croissant aux « très grands corpus » en Traitement Automatique des Langues (TAL) comme en analysetextuelle suppose de maîtriser l'homogénéité lexicale, morpho-syntaxique et syntaxique des données utilisées.Cela implique en amont le développement d'outils de calibrage de textes. Nous mettons en place de tels outilset la méthodologie associée dans le cadre de l'appel d'offres ELRA Contribution à la réalisation de corpus dufrançais contemporain. Nous montrons sur les discours radio-télévisés de De Gaulle et de Mitterrand les premiersrésultats de cette approche. Nous tirons les conséquences de cette expérience pour les traits que nous employonspour profiler les texte

Quantum reflection and Liouville transformations from wells to walls

Liouville transformations map in a rigorous manner one Schr\"odinger equation into another, with a changed scattering potential. They are used here to transform quantum reflection of an atom on an attractive well into reflection of the atom on a repulsive wall. While the scattering properties are preserved, the corresponding semiclassical descriptions are completely different. A quantitative evaluation of quantum reflection probabilities is deduced from this method

Integration of CAD and rapid manufacturing for sand casting optimisation

International audienceIn order to reduce the time and costs of the products development in the sand casting process, the SMC Colombier Fontaine company has carried out a study based on tooling manufacturing with a new rapid prototyping process. This evolution allowed the adequacy of the geometry used for the simulation to the tooling employed physically in the production. This allowed a reduction of the wall thickness to 4?mm and retained reliable manufacturing process