A robust extension to the triple plane pressure mode matching method by filtering convective perturbations

Time-periodic CFD simulations are widely used to investigate turbomachinery components. The triple-plane pressure mode matching method (TPP) developed by Ovenden and Rienstra extracts the acoustic part in such simulations. Experience shows that this method is subject to significant errors when the amplitude of pseudo-sound is high compared to sound. Pseudo-sound are unsteady pressure fluctuations with a convective character. The presented extension to the TPP improves the splitting between acoustics and the rest of the unsteady flow field. The method is simple: i) the acoustic eigenmodes are analytically determined for a uniform mean flow as in the original TPP; ii) the suggested model for convective pressure perturbations uses the convective wavenumber as axial wavenumber and the same orthogonal radial shape functions as for the acoustic modes. The reliability is demonstrated on the simulation data of a low-pressure fan. As acoustic and convective perturbations are separated, the accuracy of the results increases close to sources, allowing a reduction of the computational costs by shortening the simulation domain. The extended method is as robust as the original one--giving the same results for the acoustic modes in absence of convective perturbations.Comment: Accepted 15-05-11 by International Journal of Aeroacoustics to be published in the special issue focusing on turbomachinery aeroacoustic

Services directive : what, why, how?

EU Directive 2006/123/EC aims to facilitate freedom of establishment for service providers in other Member States and the freedom of provision of services between Member States. It also aims to promote economic growth and employment in the EU, as well as high quality services. Member states are obliged to modify their domestic law to remove any obstacles impeding the smooth development of the service activity within the Community. Requirements leading to an unjustified ban have been removed. Some national requirements are maintained if they meet the three following criteria: necessity, proportionality, and non-discrimination. France has fulfilled its obligations by writing two reports early 2010, which, once they have gone through the process of mutual evaluation by the Member States and have been accepted, will lead to a definition of the practical means of transposing the Directive into national law.L’Union Européenne institue, par la directive 2006/123/CE, un mécanisme visant à faciliter le libre établissement et la libre circulation des services et des personnes au sein d’un « grand marché intérieur des services ». Cette directive a pour objectif de favoriser la croissance économique et l'emploi dans l'UE, tout en prônant une haute qualité des services. Les États membres ont obligation de faire évoluer leur droit interne pour lever tout obstacle entravant le bon développement de l’activité de services communautaire. Les exigences induisant une interdiction non justifiée sont supprimées. Certaines exigences nationales sont sauvegardées si elles répondent aux trois critères de nécessité, de proportionnalité et de non discrimination. La France a répondu à ses obligations en rédigeant deux rapports, début 2010, qui après une évaluation mutuelle par les États membres et après acceptation, ouvriront à la définition des modalités pratiques d’application de la directive, dans le droit national

Changes in the veterinary code of ethics

The transposition of Directive 2006/123/EC into national law applies to veterinarians. The Veterinary Council has raised the issue with the aim to provide the profession with new tools to regulate the practice of animal medicine and surgery. The proposals promote a simple idea, i.e. to let veterinarians open several private practices or several veterinary companies, in return for genuine regulation. They are based on the concept of a single administrator controlling the practices, backed by proper general terms and conditions. Six aspects were examined: practice limited to one company, limited number of practices and annexes, limited number of employees or self-employed collaborators, a single administrative office, location in commercial premises and communication. These proposals should be finalised by the publication of a new code of ethics expected in 2011.La transposition de la Directive 2006/123/CE, en droit national, concerne les vétérinaires. L’Ordre vétérinaire a porté le dossier avec pour objectif de doter la profession de nouveaux outils pour encadrer l’exercice de la médecine et de la chirurgie des animaux. Les propositions reposent sur une idée simple qui est d’accepter l’ouverture de l’exercice dans plusieurs domiciles professionnels d’exercice ou dans plusieurs sociétés vétérinaires, en contrepartie d’une véritable régulation du dispositif. Elles reposent sur la notion d’administrateur de domicile professionnel d’exercice et sur la rédaction des conditions générales de son fonctionnement. Six thématiques vétérinaires ont fait l’objet d’une évaluation: les limitations à l’exercice au sein d’une société, la limitation du nombre de domiciles professionnels d’exercice et annexes, la limitation du nombre de salariés ou de collaborateurs libéraux, l’unicité du domicile professionnel administratif, l’installation dans des locaux commerciaux et la communication. Le dispositif final devrait être stabilisé par la publication d’un nouveau code de déontologie attendu en 2011

Multimodal approach to estimate the ocular movements during EEG recordings: a coupled tensor factorization method

International audienceThis paper deals with coupled tensor factorization. A relaxed criterion derived from the advanced coupled matrix-tensor factorization (ACMTF) proposed by Acar et al. is described. The proposed relaxed ACMTF (RACMTF) criterion is based on weaker assumptions that are thus more often satisfied when dealing with actual data. Numerical simulations show the benefit of using jointly two data sets when the underlying factors are highly correlated, especially if one of the modality is less noisy than the other one. The proposed method is finally applied on actual Gaze&EEG data to estimate the ocular artifacts into the EEG recordings

A statistical mixture method to reveal bottom-up and top-down factors guiding the eye-movements

When people gaze at real scenes, their visual attention is driven both by a set of bottom-up processes coming from the signal properties of the scene and also from top-down effects such as the task, the affective state, prior knowledge, or the semantic context. The context of this study is an assessment of manufactured objects (here car cab interior). From this dedicated context, this work describes a set of methods to analyze the eye-movements during the visual scene evaluation. But these methods can be adapted to more general contexts. We define a statistical model to explain the eye fixations measured experimentally by eye-tracking even when the ratio signal/noise is bad or lacking of raw data. One of the novelties of the approach is to use complementary experimental data obtained with the “Bubbles” paradigm. The proposed model is an additive mixture of several a priori spatial density distributions of factors guiding visual attention. The “Bubbles” paradigm is adapted here to reveal the semantic density distribution which represents here the cumulative effects of the top-down factors. Then, the contribution of each factor is compared depending on the product and on the task, in order to highlight the properties of the visual attention and the cognitive activity in each situation