Active control of a clamped beam equipped with piezoelectric actuator and sensor using generalized predictive control

of a flexible structure is here presented. The studied structure is a clamped-free beam equipped with collocated piezoelectric actuator/sensor. Piezoelectric transducers advantages lie in theirs compactness and reliability, making them commonly used in aeronautic applications, context in which our study fits. Theirs collocated placement allow the use of well-known control strategies with guaranteed stability. First an analytical model of this equipped beam is given, using the Hamilton's principle and the Rayleigh-Ritz method. After a review of the experimental setup (and notablv of the piezoelectric transducers), two control laws are described. The chosen one - Generalized Predictive Control (GPC) - will be compared to a typical control law in the domain of flexible structures, the Positive Position Feedback, one of the control lam mentioned above. Majors benefits of GPC lie in its robustness in front of model uncertainties and others disturbances. The results given come from experiments on the structure, performed thanks to a DSP. GPC appears to suit for the considered study's context (i.e. damping of the first vibration mode). Some improvements may, be reached. Among them, a more complex structure with more than a single mode to damp, and more uncertainties may be considered

Tree species identification on large-scale aerial photographs in a tropical rain forest, French Guiana—application for management and conservation

International audienceManagement and conservation planning of any ecosystem requires knowledge of species composition. This is a real challenge in tropical rain forests that are characterised by very high species richness and canopy access limitations. The possibility of approaching trees from remote sensing on large-scale aerial photographs, takes on its full significance in this context. Results of tree species identification by photo-interpretation in a French Guianan forest canopy are discussed, as well as an overview of the part of the forest accessible from the photographs. Two sets of aerial photographs were used. One set (1:3700 colour slides) covers 15 ha of primary forest, divided into a training set (TS, 5 ha) and a validation set (VS 1: 10 ha). Another validation set, taken in different conditions of acquisition, scale and season, is available for an adjacent area (VS 2: 6.5 ha). Aerial photographs captured a quarter of the tree community (dbh ! 10 cm) on average, and about 45% of the SGS (Species or Group of Species) on the training set. The crown appearance of 12 major canopy SGS, including commercial species and species of ecological interest, had been described in a previous work on the same training set. Following these descriptions, two photo-interpreters separately identified 309 tree crowns overall on VS 1, with a good agreement in their respective judgements. After their interpretations were checked in the field, the overall average identification success was high (87%) but the results varied according to the SGS. The results on VS 2 showed that some species displayed major seasonal and scale variations and were hardly recognized, whereas some others could be identified without modifying the learning process. The results are encouraging and this work will be extended as the identification of tropical rain forest trees from remote sensing has many applications, ranging from fundamental ecological knowledge of canopy species to the management and conservation of such highly diverse and hardly inventoried ecosystems

La gestion par les processus dans la banque : de l'intention à la mise en oeuvre

La gestion par les processus a connu son heure de gloire dans le secteur industriel, confronté à un environnement en perpétuelle évolution où réactivité et flexibilité sont les maîtres mots. Les banques françaises s'inscrivent aujourd'hui dans ces mêmes problématiques. Pourtant, l'étude de cas présentée dans cet article, au travers de l'analyse critique de la mise en place d'un processus au sein d'une banque régionale de détail, expose la difficulté pour les groupes d'acteurs impliqués dans cette démarche à mettre en œuvre des leviers d'action visant une réorganisation, même mineure, des structures ; ceux-ci adoptant au final une attitude plutôt conservatrice des logiques bureaucratiques ancrées depuis de nombreuses années. Ce cas nous enseigne alors la difficile mise en œuvre de la transversalité dans les organisations bancaires.Management par les processus; Banque; Transversalité; Recherche-action.

A Security Supervision System for Hybrid Networks

The traditional way of protecting networks and applications with e.g., firewalls and encryption, is no longer sufficient to protect effectively emerging hybrid wired-cum-wireless networks including ad hoc networks. Intrusion detection mechanisms should be coupled with preventive measures so as to identify unauthorised abuses. To this end, we propose a novel Hybrid Distributed Security Operation Center (HDSOC) which collects logs that are generated by any application/service, layer of the protocol stack or resource (e.g., router), providing a global view of the supervised system based on which complex and distributed intrusions can be detected. Our HDSOC further (i) distributes its capabilities and (ii) provides extensive coordination capabilities for guarantying that both the networks and the HDSOC components do not constitute isolated entities largely unaware of each others

Separation Methods hyphenated to Mass Spectrometry for the Characterization of the Protein Glycosylation at the Intact Level

International audienceGlycosylation is one of the most common post-translational modifications of proteins that affects their biological activity, solubility, and half-life. Therefore, its characterization is of great interest in proteomic, particularly from a diagnostic and therapeutic point of view. However, the number and type of glycosylation sites, the degree of site occupancy and the different possible structures of glycans can lead to a very large number of isoforms for a given protein, called glycoforms. The identification of these glycoforms constitutes an important analytical challenge. Indeed, to attempt to characterize all of them, it is necessary to develop efficient separation methods associated with a sensitive and informative detection mode, such as mass spectrometry (MS). Most analytical methods are based on bottom-up proteomics, which consists in the analysis of the protein at the glycopeptides level after its digestion. Even if this approach provides essential information, including the localization and composition of glycans on the protein, it is also characterized by a loss of information on macro-heterogeneity, i.e. the nature of the glycans present on a given glycoform. The analysis of glycoforms at the intact level can overcome this disadvantage. The aim of this review is to detail the state-of-the art of separation methods that can be easily hyphenated with MS for the characterization of protein glycosylation at the intact level. The different electrophoretic and chromatographic approaches are discussed in detail. The miniaturization of these separation methods is also discussed with their potential applications. While the first studies focused on 2 the development and optimization of the separation step to achieve high resolution between isoforms, the recent ones are much more application-oriented, such as clinical diagnosis, quality control, and glycoprotein monitoring in formulations or biological samples

Bifix codes and interval exchanges

We investigate the relation between bifix codes and interval exchange transformations. We prove that the class of natural codings of regular interval echange transformations is closed under maximal bifix decoding.Comment: arXiv admin note: substantial text overlap with arXiv:1305.0127, arXiv:1308.539

Electrocorticographic recording of cerebral cortex areas manipulated using an adeno-associated virus targeting cofilin in mice

The use of electrocorticographic (ECoG) recordings in rodents is relevant to sleep research and to the study of a wide range of neurological conditions. Adeno-associated viruses (AAVs) are increasingly used to improve understanding of brain circuits and their functions. The AAV-mediated manipulation of specific cell populations and/or of precise molecular components has been tremendously useful to identify new sleep regulatory circuits/molecules and key proteins contributing to the adverse effects of sleep loss. For instance, inhibiting activity of the filamentous actin-severing protein cofilin using AAV prevents sleep deprivation-induced memory impairment. Here, a protocol is described that combines the manipulation of cofilin function in a cerebral cortex area with the recording of ECoG activity to examine whether cortical cofilin modulates the wakefulness and sleep ECoG signals. AAV injection is performed during the same surgical procedure as the implantation of ECoG and electromyographic (EMG) electrodes in adult male and female mice. Mice are anesthetized, and their heads are shaved. After skin cleaning and incision, stereotaxic coordinates of the motor cortex are determined, and the skull is pierced at this location. A cannula prefilled with an AAV expressing cofilinS3D, an inactive form of cofilin, is slowly positioned in the cortical tissue. After AAV infusion, gold-covered screws (ECoG electrodes) are screwed through the skull and cemented to the skull with gold wires inserted in the neck muscles (EMG electrodes). The animals are allowed three weeks to recover and to ensure sufficient expression of cofilinS3D. The infected area and cell type are verified using immunohistochemistry, and the ECoG is analyzed using visual identification of vigilance states and spectral analysis. In summary, this combined methodological approach allows the investigation of the precise contribution of molecular components regulating neuronal morphology and connectivity to the regulation of synchronized cerebral cortex activity during wakefulness and sleep

Statistical Analysis of Mother-infant (3 to 9 months) Perceptive System Communication

PILE (Programme International pour le Langage de l'Enfant), the International Program for Child Language aims to describe the processes leading to the emergence of speech in infants thanks to statistic techniques. A qualitative data base was established on the basis of one minute video sequences (the statistical units) of babies aged from 3 to 9 months interacting with their mothers. The phenomenon under study is the process of speech construction. The 110 infants are belonging to seven cohorts: infants without disorders, hospitalized infants, premature infants, infants of visually deficient mothers, infants of blind mothers, infants with neurological disorders. We present a statistical study of this data base through inferential techniques (non parametric comparison tests) and factorial analyses. Some of our findings confirm or bring additional precision to clinical hypotheses concerning the impact of certain factors, such as age cohort, calendar age, infant's sex. The statistical results describing the infant's behavior while interacting with its mother indicate that the development of the baby's perceptive system is central in the construction of language precursors

Analyse statistique de la communication par le système perceptif d'un bébé (de 3 à 9 mois) avec sa mère

PILE (Programme International pour le Langage de l'Enfant, 2004--2008), s'est donné comme objectif de décrire par des techniques statistiques les processus chez le bébé qui participent à l'émergence de la parole. Une base de données qualitative a été élaborée à partir de séquences vidéo de bébés de 3 mois à 9 mois en interaction avec leur mère. Nous présentons une étude statistique de cette base, à l'aide de techniques inférentielles (tests de comparaisons non paramétriques) et d'analyses factorielles. Certains de nos résultats confirment ou précisent les hypothèses cliniques relativement à l'effet de certains facteurs tels que cohortes, âge calendaire, sexe des bébés. Les résultats qui décrivent statistiquement le comportement du bébé en interaction avec sa mère indiquent que la mise en place du système perceptif chez le bébé est centrale dans la construction des précurseurs du langage

Dispersion of magnetic nanoparticles in a nematic liquid crystal host: Phase diagram, Fredericks transition and deformation of droplets

During the seventies when the main properties of magnetic fluids were first understood, (superparamagnetism, birefringence, hydrodynamics instabilities...) theoreticians [1] have imagined the possible advantages of a ferrofluid with a thermotropic nematic liquid crystal (LC) as a solvent. Such a “ferronematic” would indeed combine the properties of two systems which become optically anisotropic (birefringent) under electrical and magnetic fields. The today widely used liquid crystals displays (LCDs) are based on the transition between transparent and opaque state of LCs, controlled by electric fields. For certain applications, magnetic fields could be used instead if we could lower down the threshold magnetic field intensity Hc of the so called Fredericks transition arising from the competition between alignment of LC molecules by surfaces and by an applied magnetic field. This idea motivated our experimental study of dispersion of nanoparticles made of maghemite iron oxide (Γ-Fe2O3) and 5-CB, one of the most standard nematic LCs which is convenient due to its nematic-isotropic temperature (TN-I=35°C) slightly above room temperature. However, we found that a true (monophasic) ferrofluid with 5-CB as solvent can be obtained only in the isotropic phase (above TN-I), whereas in the nematic state, the system separates between two phases: one the one hand magnetic microdroplets made of a high concentration of magnetic nanoparticles (about 18 vol% from SAXS measurements) in isotropic 5-CB and on the other hand a non magnetic 5-CB nematic matrix [2]. This phenomenon was explained by the thermodynamic laws for a ternary system (nanoparticles – LC – surfactant). Two aspect of these highly magnetic droplets in a LC host matrix where studied : i) their influence on the threshold field Hc of the Fredericks transition of a 5-CB layer sandwitched between two plates with homeotropic alignment conditions; ii) their strong ellipsoidal deformation under a magnetic field of low intensity, which – by analogy with ferrofluid droplets in a non magnetic liquid – provides an experimental measurement of the interfacial tension and tentatively of the anchoring energy of LC molecules onto nanoparticles [3]. ___________________________________________________ [1] F. Brochard, P. G. de Gennes, J. Phys. (Paris), 1970, 31, 691. [2] C. Da Cruz, O. Sandre, V. Cabuil, Journal of Phyical Chemistry B (2005) 109, 14292. [3] J. Deseigne, report of ESPCI engineering school short training period (March 2006)