Production factor returns : the role of factor utilisation

Short-term increasing returns to production factors are usually found in empirical studies. We argue they can be due to omitted variables, particularly the intensity of factor utilisation. Thanks to original French firm-level data (1992-2008), we show how increasing returns to scale disappear when working time, capacity utilisation rate and mainly capital operating time are introduced in the production functionProduction function, productivity, factor returns.

Numerical simulation of a 3D unsteady two-phase flow in the filling cavity in oxygen of a cryogenic rocket-engine

The feeding of the LOX dome of a cryogenic rocket-engine is a decisive stage of the transient engine ignition. However flight conditions are difficult to reproduce by experimental ground tests. The work reported here is part of an ongoing research effort to develop a robust method for prediction and understanding the LOX dome feeding. In the framework of this project, experiments with substition fluids (air and water) are conducted, without mass and energy transfer. This work presented here intends to reproduce these experiments through incompressible two-phase flow CFD simulations, in an industrial geometry equivalent to the experimental mock-up, made up of a feeding piper, a dome and 122 injectors. More precisely, the aim is to compare the numerical results obtained with NEPTUNE CFD code with the experimental results, through the dome pressure and the mass flow rate of water at the outlet. An important work was made to obtain the same inlet conditions in NEPTUNE CFD code as the experimenters, in order to compare the numerical results with the experimental results for the best. The influence of the interfacial momentum transfer modeling and turbulence modeling are also studied here. The turbulence modeling plays no macroscopic or local role on the mass flow rate of water, on the mass of water in dome and on the dome pressure. The drag model has a major impact on our results as well globally as locally, unlike the turbulence modeling. The Simmer-like model is prefered in comparison to the Large Interface called LIM, because it is in better agreement with experimental data. Moreover, it has to be highlighted that the Simmer-like model is very sensitive to its parameter d, the inclusion diameter

Striving for innovation; working in CFT - a case study of Audi

The purpose of this thesis is to study and determine how working in cross functional teams can generate value in an effort to facilitate innovation. An inductive scientific perspective is chosen as the research approach. A single case is investigated with the theoretical framework based on Resource Based View, Intellectual Capital, Innovation theory and theories concerning Cross Functional Teams. The empirical material has been collected through primary data; surveys, interviews and secondary data; literature, websites and further complementary data. The practice of using Cross Functional Teams will enhance organizational learning, knowledge transfer, increase communication and innovation, which in turn will increase the speed and performance of the new product development process. The research shows that a firm’s internal resources (human,- structural and intellectual capital) are a fundamental source of value creation. Effective cross functional teamwork creates an environment which stimulates creativity and strengthens the human- and structural capital leading to increased intellectual capital, suggesting the intangible resources to be the main source of competitive advantage

Auditory feedback in VR and HCI

International audienceWe call auditory feedback the feedback generated in response to a subject gesture when performing an action, and perceived by the subject's or the auditor's auditory perceptio

Compétences interactionnelles des tuteurs dans des échanges vidéographiques synchrones

International audienceThis article studies the interactional dynamics at work in a teaching set-up that puts future teachers of French as a foreign language in relation with distant learners via webbased videoconferencing. The analysis of the verbal interactions allows identifying whether the teacher trainees' verbal regulation deployed to manage the pedagogical interaction is conducive to the development of the learners' communication skillsCet article s'intéresse aux dynamiques interactionnelles observables dans un dispositif didactique mettant en relation de futurs enseignants en formation en Français langue étrangère avec des apprenants, par le biais de rencontres synchrones par visioconférence. Une analyse des interactions verbales permet d'identifier les conduites langagières des apprentis-tuteurs et s'attelle à déterminer dans quelle mesure celles-ci sont susceptibles d'influencer la mise en œuvre par les apprenants de certaines compétences de communication

Rough surface RCS measurements and simulations using the Physical Optics Approximation

International audienceThe objective of this article is to develop innovative approaches to obtain analytical expressions of the Radar Cross Section (RCS) of perfectly-conducting random rough surfaces under the Physical Optics (PO) approximation. The led approaches take into account the specific geometrical properties of the considered surfaces to calculate their RCS. The objective is to reduce the computing time with respect to the numerical PO technique, which requires two numerical integrations. All developed approaches are validated by comparison with a commercial code (the MLFMM of FEKO), used as a reference, and with measurements performed on three selected rough surfaces samples

Approche fiabiliste pour l’optimisation locale d’un problème couplé fluide-structure

Le projet OSYCAF (Optimisation d’un Système Couplé fluide/structure représentant une Aile Flexible) a pour objectif de proposer une méthodologie d’optimisation multidisciplinaire dans un contexte aéronautique. Plus précisément, il s’agit d’optimiser une aile d’avion en tenant compte des interactions fluide-structure. Les modèles de mécanique des fluides et des structures sont des disciplines devant communiquer entre elles et avec l’optimiseur global. L’optimisation est réalisée sur deux niveaux : par rapport aux paramètres globaux, communs aux deux disciplines, et par rapport aux paramètres locaux, propres à chacune. Le travail présente l’optimisation de la structure par rapport aux paramètres locaux. Dans ce cadre, il est proposé d’introduire des incertitudes probabilistes permettant de tenir compte de contraintes de fiabilité