Le passage aux Normes internationales : de nouvelles options pour la gestion du résultat ?

Les sociétés européenne cotées ont dû adopter au premier janvier 2005 toutes les Normes et interprétations de l'IASB (Normes IAS / IFRS ). Le passage à ces Normes offre aux entreprises plusieurs options comptables et maintient une large part d'interprétation. Ces options et estimations se sont manifestées soit pour les besoins de la transition (retraitement ou non des acquisitions antérieures, valorisation des immobilisations à la juste valeur, traitement des écarts actuariels, des instruments financiers et des écarts de conversion cumulés), soit pour les exercices postérieurs (Valorisation des immobilisations, classification des contrats de location, capitalisation des frais de développement). Les options offertes viennent renforcer la panoplie des choix comptables dont disposait le dirigeant pour le pilotage du résultat. Les recherches de la théorie politico-contractuelle et ses résultats ne devraient donc pas être remis en cause. Les trois principales hypothèses défendues (rémunération du dirigeant, covenants bancaires et taille) demeurent donc vérifiables. Les conclusions des principaux travaux de recherche que nous reprenons pourraient s'appliquer pour des entreprises passées aux Normes IAS / IFRS.Normes internationales ; IAS ; IFRS ; Théorie politico contractuelle ; Gestion du résultat ; Gouvernance

Model for movement classification of the bicep

This project introduces a classification model whose purpose is the distinction between the two possible movements done by the bicep; namely flexion and rotation. Surface EMG data was collected using the MIKROE-2621. It was later sampled from Analog to Digital by a Nucleo 401-RE board at 200 Hz. To generate the dataset, I connected the apparatus to my arm and performed the movements a total number of 300 times. This data was later analyzed and a choice of features were made that eventually was fed into MATLAB Classification Learner. A Support Vector Machine performed best and was able to classify the movements at a 94.3 % accuracy rate. This report shows the different techniques used to analyze the data and how I developed an understanding of the principal components that govern this classification using statistical methods

Lien entre la préférence d’oviposition et la performance subséquente des larves chez la mineuse des agrumes Phyllocnistis citrella Stainton [Lepidoptera : Gracillariidae]

La femelle de la mineuse des agrumes Phyllocnistis citrella [Lepidoptera : Gracillariidae] recherche de façon préférentielle les jeunes feuilles, riches en éléments nutritifs, pour pondre ses oeufs et délaisse les feuilles âgées. La femelle a aussi tendance à revenir sur un hôte où un dépôt d’oeufs en surnombre a préalablement été effectué par d’autres femelles. Il s’en suit une forte mortalité larvaire. Toutefois, la taille des survivants n’est pas affectée parce que la régulation se fait par élimination des individus surnuméraires.[Relationship between oviposition preference and the subsequent performance of citrus leafminer Phyllocnistis citrella [Lepidoptera: Gracillariidae] larvae]The female citrus leafminer Phyllocnistis citrella [Lepidoptera: Gracillariidae] principally favours young leaves that are the richest in nutritive elements to lay eggs and leaves aside the oldest ones. Females also tend to come back to a host already infested with supernumerary egg deposition by other females. The result of this behaviour is a high larval mortality, but the size of the survivors is not affected as regulation occurs through the elimination of supernumerary individuals

Event count distributions from renewal processes : fast computation of probabilities

Discrete distributions derived from renewal processes, i.e. distributions of the number of events by some time t are beginning to be used in management science, econometrics and health sciences. A new fast method is presented for computation of the probabilities for these distributions. This will enable practitioners in management science to exploit this rich class of models. We calculate the count probabilities by repeatedly convolving the discretized distribution, and then correct them using Richardson extrapolation. When just one probability is required, a second algorithm is described, an adaptation of De Pril's method, in which the computation time does not depend on the ordinality, so that even high-order probabilities can be rapidly found. Any survival distribution can be used to model the inter-arrival times, which gives models with great flexibility for modelling both underdispersed and overdispersed data. This work could pave the way for the routine use of these distributions as an additional tool for modelling event count data. An empirical example using fertility data illustrates the use of the method and has been fully implemented using an R package Countr developed by the authors and available from the Comprehensive R Archive Network (CRAN)

H∞ Loop shaping control for PLL-based mechanical resonance tracking in NEMS resonant mass sensors

International audienceAbstract--A simple dynamic detection of the resonance frequency shift in NEMS resonant mass sensors is described. This is done without the use of an external frequency sweep signal nor a frequency counter limiting the dynamic variation detection. Neither an amplitude control nor a phase switcher is required for maintaining the resonant oscillations. The sensor is driven directly by the VCO's output for which the control signal is calculated by a robust H∞ controller using loopshaping method. Only the sensor and the VCO's signals signs are detected and compared so that the controller regulates the phase difference between them, maintaining it at π / 2 which occurs on resonance frequency. The measurement issue is transformed to a novel control problem that rejects the disturbance described by the resonance frequency shift, attenuates the phase noise and guarantees good stability margins

Friction and wear behaviors of Fe-14Mn-9Cr-5Ni-6Si and Fe-13Cr-12Co-8Mn-6Ni-6Si shape memory alloys

363-368Iron-based shape memory alloys are the materials that can be especially used in civil engineering structures and pipe coupling because of their good mechanical properties and their low price compared with Ni-Ti and cooper-based alloys. However, their applications have been remained limited so it is very important to determine the wear behaviours of this family of materials. This paper presents friction and wears behaviours of Fe-14Mn-9Cr-5Ni-6Si and Fe-13Cr-12Co-8Mn-6Ni-6Si under both dry and lubricated conditions by means of reciprocating ball-on-flat tribometer. The aim of this study is to determine the influence of chemical composition of iron-based shape memory alloys on tribological behaviours of material and compare their behaviours with that of Fe-32Mn-6Si which is considered as a basis reference. Morphologies and microstructures of specimens have been characterized by optical microscope. The wear tests and the optical micrograph observations of studied alloys have shown that the tribological behaviors of shape memory alloys depend on the chemical composition of material which is mainly influenced by the presence of nickel, chromium and cobalt in material. The results have shown that friction coefficients of Fe-14Mn-9Cr-5Ni-6Si and Fe-13Cr-12Co-8Mn-6Ni-6Si are almost equal and less than of Fe-32Mn-6Si. Moreover, the addition of cobalt in the chemical composition of shape memory alloys reduces considerably the stick-slip phenomenon. It has been also shown that wear resistance of alloys in oily friction is higher than that in dry friction

Microbeam dynamic shaping by closed-loop electrostatic actuation using modal control

International audienceA closed-loop control approach for the dynamic shaping of a microbeam by electrostatic actuation is described. Starting from a desired displacements reference vector of N small segments of the beam (representing the approximation of the continuous case), n controllers (n is the number of considered modes) output the stresses that must be distributed throughout the beam, on the N actuators. Because this reference may vary with time, the controllers are designed so that they accomplish good response dynamics, as well as performance and robustness specifications. The innovation in this method is that we control the dynamic coefficients associated to the modes of the microbeam and not directly the physical displacements in each small segment, which reduces the number of correctors from N to the number of n modes to control