Confiance et gouvernement des entreprises: le rôle de la confiance dans la relation capital-investisseurs et dirigeants et son influence sur la performance

Ce papier de recherche étudie l'influence du niveau de confiance interpersonnelle existant entre capital investisseurs et dirigeants d'entreprise sur trois types de variables : les processus d'interaction qui caractérisent leur relation, les rôles tenus par les capital investisseurs vis à vis des dirigeants dans la phase post-investissement, et, par l'intermédiaire de ces processus et rôles, sur la performance financière de l'investissement dans les entreprises concernées. Notre hypothèse centrale est que la confiance favorise les processus d'interaction et les rôles des capital investisseurs qui ont une influence positive sur la performance financière des entreprises, et donc sur celle de l'investissement qui a été opéré dans ces entreprises. Nous utilisons un cadre théorique éclectique (théorie de l'agence d'une part, théories de la confiance et de la coopération d'autre part) pour construire un modèle qui fait l'objet d'un test empirique au moyen d'une enquête par questionnaire sur un échantillon d'opérations de LBOs réalisés en France. Nos résultats montrent que le niveau de confiance interpersonnelle influe sur l'ensemble des processus d'interaction, ainsi que sur un nombre limité de rôles des capital investisseurs. Par contre ils ne mettent en évidence aucune relation directe entre confiance et performance financière de l'investissement.capital investissement; capital risque; LBO; gouvernement d'entreprise; conseil d'administration; dirigeants, confiance; coopération

A non-parametric probabilistic model for soil-structure interaction

International audienceThe paper investigates the effect of soil-structure interaction on the dynamic response of structures. A non-parametric probabilistic formulation for the modelling of an uncertain soil impedance is used to account for the usual lack of information on soil properties. Such a probabilistic model introduces the physical coupling stemming from the soil heterogeneity around the foundation. Considering this effect, even a symmetrical building displays a torsional motion when submitted to earthquake loading. The study focuses on a multi-story building modeled by using equivalent Timoshenko beam models which have different mass distributions. The probability density functions of the maximal internal forces and moments in a given building are estimated by Monte Carlo simulations. Some results on the stochastic modal analysis of the structure are also given

Étude comparée des gouvernances de Boeing et d'EADS et de leurs impacts sur les stratégies et performances financières

La crise qu'a traversé EADS dans les années 2007-2008 est un excellent cas d'école sur la gouvernance des entreprises et et l'importance de son architecture pour développer des projets viables dans un univers compétitif.Gouvernance; EADS; Boeing; performances financières

Detection of single DNA molecules by multicolor quantum-dot end-labeling

Observation of DNA–protein interactions by single molecule fluorescence microscopy is usually performed by using fluorescent DNA binding agents. However, such dyes have been shown to induce cleavage of the DNA molecule and perturb its interactions with proteins. A new method for the detection of surface-attached DNA molecules by fluorescence microscopy is introduced in this paper. Biotin- and/or digoxigenin-modified DNA fragments are covalently linked at both extremities of a DNA molecule via sequence-specific hybridization and ligation. After the modified DNA molecules have been stretched on a glass surface, their ends are visualized by multicolor fluorescence microscopy using conjugated quantum dots (QD). We demonstrate that under carefully selected conditions, the position and orientation of individual DNA molecules can be inferred with good efficiency from the QD fluorescence signals alone. This is achieved by selecting QD pairs that have the distance and direction expected for the combed DNA molecules. Direct observation of single DNA molecules in the absence of DNA staining agent opens new possibilities in the fundamental study of DNA–protein interactions. This work also documents new possibilities regarding the use of QD for nucleic acid detection and analysis

Multiframe Scene Flow with Piecewise Rigid Motion

We introduce a novel multiframe scene flow approach that jointly optimizes the consistency of the patch appearances and their local rigid motions from RGB-D image sequences. In contrast to the competing methods, we take advantage of an oversegmentation of the reference frame and robust optimization techniques. We formulate scene flow recovery as a global non-linear least squares problem which is iteratively solved by a damped Gauss-Newton approach. As a result, we obtain a qualitatively new level of accuracy in RGB-D based scene flow estimation which can potentially run in real-time. Our method can handle challenging cases with rigid, piecewise rigid, articulated and moderate non-rigid motion, and does not rely on prior knowledge about the types of motions and deformations. Extensive experiments on synthetic and real data show that our method outperforms state-of-the-art.Comment: International Conference on 3D Vision (3DV), Qingdao, China, October 201

Solving the hypersingular boundary integral equation for the Burton and Miller formulation

International audienceThis paper presents an easy numerical implementation of the Burton and Miller (BM) formulation, where the hypersingular Helmholtz integral is regularized by identities from the associated Laplace equation and thus needing only the evaluation of weakly singular integrals. The Helmholtz equation and its normal derivative are combined directly with combinations at edge or corner collocation nodes not used when the surface is not smooth. The hypersingular operators arising in this process are regularized and then evaluated by an indirect procedure based on discretized versions of the Calderón identities linking the integral operators for associated Laplace problems. The method is valid for acoustic radiation and scattering problems involving arbitrarily shaped three-dimensional bodies. Unlike other approaches using direct evaluation of hypersingular integrals, collocation points still coincide with mesh nodes, as is usual when using conforming elements. Using higher-order shape functions (with the boundary element method model size kept fixed) reduces the overall numerical integration effort while increasing the solution accuracy. To reduce the condition number of the resulting BM formulation at low frequencies, a regularized version α = ik/(k2 + λ) of the classical BM coupling factor α = i/k is proposed. Comparisons with the combined Helmholtz integral equation Formulation method of Schenck are made for four example configurations, two of them featuring non-smooth surfaces