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Lanusse P.,Bordeaux INP | Sabatier J.,French National Center for Scientific Research | Oustaloup A.,Bordeaux INP
IFAC Proceedings Volumes (IFAC-PapersOnline) | Year: 2014

This paper presents how common PID controllers have been generalized to fractional order PID controllers and how the additional tuning parameters can be used to meet more requirements. It is shown that the first generation CRONE control-system design methodology is able to provide robust fractional order PID for uncertain gain perturbed plants. © IFAC.


Rummens F.,University of Bordeaux 1 | Renaud S.,French National Center for Scientific Research | Lewis N.,Bordeaux INP
Conference Proceedings - 13th IEEE International NEW Circuits and Systems Conference, NEWCAS 2015 | Year: 2015

We present a CMOS differential neural amplifier with high input impedance, which topology is inspired by the instrumentation amplifier. The miniaturization of the MEAs goes with an increase of the electrodes impedance and necessitates high input impedance neural amplifiers; otherwise it results in a significant loss of signal and low SNR. The circuit presented here is designed on a 0.35 μm CMOS technology. Two versions are described which capacitive input impedance is 1 pF. One is robust to high input offset and consumes 13.5 μA; the other one is more sensitive to offset but consumes only 3.7 μA. Both generate less than 7 μVRMS input-referred noise and their NEF figures are respectively 8.4 and 3.66. These features are competitive in view of the literature on neural amplifiers, while the circuit was specifically designed to present a high input impedance. © 2015 IEEE.


News Article | December 22, 2016
Site: phys.org

Confocal microscope observations of three types of vesicles. In red, methylene blue-loaded vesicles; in green, calcein-loaded vesicles. Sucrose-loaded vesicles are indicated by an arrow. Laser irradiation of 633 nm then 488 nm ruptures the red and green vesicles in succession. The other vesicle remains intact. Credit: Peyret et al. 2016. Cells are the site of a multitude of chemical reactions, the precision of which is envied by scientists. A team of researchers from the CNRS and Bordeaux INP have neared this level of control by controlling the explosion of polymersomes through laser irradiation. These hollow polymer spheres, which can mimic certain cellular functions, react to a specific wavelength and thus release their content on demand. This research has been published in Angewandte Chemie International Edition. Polymersomes are artificial vesicles that can mimic organelles, compartments naturally found in nucleic cells. Here researchers encapsulated fluorescent molecules in "giant" polymersomes with a diameter of a dozen micrometers. These fluorescent groups have the characteristic of decomposing under the action of light, but only at a specific wavelength. A suitable level of irradiation degrades these molecules and thus increases the solute concentration within the polymersomes. This entails an imbalance, which, because the polymersomes are relatively impermeable, cannot be compensated sufficiently rapidly. The vesicles are thus forced to rupture. The team designed three types of polymersomes, each containing a specific fluorescent group, meant to react to different wavelengths. The researchers attained such a level of control that they were able to observe the vesicles and target them individually using a confocal microscope equipped with adequate lasers. In addition to light, other methods of control are currently being developed by researchers to rupture microvesicles: temperature, pH, magnetic fields and so on. This research could have medical applications in the long term, but for the time being researchers are studying the possibility of releasing substances in a controlled manner within artificial polymer cells, in order to be able to reproduce and better understand some of the metabolic reactions of the biological cell. More information: Ariane Peyret et al. Polymersome Popping by Light-Induced Osmotic Shock under Temporal, Spatial, and Spectral Control, Angewandte Chemie (2016). DOI: 10.1002/ange.201609231


Abdulsamad F.,CNRS Transfers and Interactions in Hydrosystems and Soils | Florsch N.,CNRS Transfers and Interactions in Hydrosystems and Soils | Florsch N.,Paris-Sorbonne University | Schmutz M.,Bordeaux INP | Camerlynck C.,CNRS Transfers and Interactions in Hydrosystems and Soils
Journal of Applied Geophysics | Year: 2016

During the last decades, the usage of spectral induced polarization (SIP) measurements in hydrogeology and detecting environmental problems has been extensively increased. However, the physical mechanisms which are responsible for the induced polarization response over the usual frequency range (typically 1. mHz to 10-20. kHz) require better understanding. The phase shift observed at high frequencies is sometimes attributed to the so-called Maxwell-Wagner polarization which takes place when charges cross an interface. However, SIP measurements of tap water show a phase shift at frequencies higher than 1. kHz, where no Maxwell-Wagner polarization may occur. In this paper, we enlighten the possible origin of this phase shift and deduce its likely relationship with the types of the measuring electrodes. SIP Laboratory measurements of tap water using different types of measuring electrodes (polarizable and non-polarizable electrodes) are carried out to detect the origin of the phase shift at high frequencies and the influence of the measuring electrodes types on the observed complex resistivity. Sodium chloride is used to change the conductivity of the medium in order to quantify the solution conductivity role. The results of these measurements are clearly showing the impact of the measuring electrodes type on the measured phase spectrum while the influence on the amplitude spectrum is negligible. The phenomenon appearing on the phase spectrum at high frequency (>. 1. kHz) whatever the electrode type is, the phase shows an increase compared to the theoretical response, and the discrepancy (at least in absolute value) increases with frequency, but it is less severe when medium conductivity is larger. Additionally, the frequency corner is shifted upward in frequency. The dependence of this phenomenon on the conductivity and the measuring electrodes type (electrode-electrolyte interface) seems to be due to some dielectric effects (as an electrical double layer of small relaxation time formed at the electrodes interface). Therefore, this dielectric response should be taken into account at high frequency to better analytically separate the medium own response from that linked to the measuring electrodes used. We modeled this effect by adding a capacitance connected in parallel with the traditional equivalent electric circuit used to describe the dielectric response of medium. © 2016 Elsevier B.V.


Cohen G.J.V.,Bordeaux INP | Jousse F.,Bordeaux INP | Luze N.,Bordeaux INP | Hohener P.,Aix - Marseille University | Atteia O.,Bordeaux INP
Journal of Contaminant Hydrology | Year: 2016

Source delineation of hydrocarbon contaminated sites is of high importance for remediation work. However, traditional methods like soil core extraction and analysis or recent Membrane Interface Probe methods are time consuming and costly. Therefore, the development of an in situ method based on soil gas analysis can be interesting. This includes the direct measurement of volatile organic compounds (VOCs) in soil gas taken from gas probes using a PID (Photo Ionization Detector) and the analysis of other soil gases related to VOC degradation distribution (CH4, O2, CO2) or related to presence of Light Non-Aqueous Phase Liquid (LNAPL) as 222Rn. However, in widespread heterogeneous formations, delineation by gas measurements becomes more challenging. The objective of this study is twofold: (i) to analyse the potential of several in situ gas measurement techniques in comparison to soil coring for LNAPL source delineation at a heterogeneous contaminated site where the techniques might be limited by a low diffusion potential linked to the presence of fine sands and silts, and (ii) to analyse the effect of vertical sediment heterogeneities on the performance of these gas measurement methods. Thus, five types of gases were analysed: VOCs, their three related degradation products O2, CO2 and CH4 and 222Rn. Gas measurements were compared to independent LNAPL analysis by coring. This work was conducted at an old industrial site frequently contaminated by a Diesel-Fuel mixture located in a heterogeneous fine-grained aquifer. Results show that in such heterogeneous media migration of reactive gases like VOCs occurs only across small distances and the VOC concentrations sampled with gas probes are mainly related to local conditions rather than the presence of LNAPL below the gas probe. 222Rn is not well correlated with LNAPL because of sediment heterogeneity. Oxygen, CO2, and especially CH4, have larger lengths of diffusion and give the clearest picture for LNAPL presence at this site even when the gas probe is somewhat distant. © 2016 Elsevier B.V. All rights reserved.


Atlan A.,CNRS Ecosystems, Biodiversity, and Evolution Laboratory | Hornoy B.,Laval University | Delerue F.,Bordeaux INP | Gonzalez M.,Bordeaux INP | And 2 more authors.
PLoS ONE | Year: 2015

Phenotypic plasticity may be advantageous for plants to be able to rapidly cope with new and changing environments associated with climate change or during biological invasions. This is especially true for perennial plants, as they may need a longer period to respond genetically to selective pressures than annuals, and also because they are more likely to experience environmental changes during their lifespan. However, few studies have explored the plasticity of the reproductive life history traits of woody perennial species. This study focuses on a woody shrub, Ulex europaeus (common gorse), and on the response of its reproductive traits to one important environmental factor, shading. The study was performed on clones originating from western France (within the native range of this invasive species) and grown for seven years.We compared traits of plants grown in a shade treatment (with two successive shade levels) vs. full natural light. The traits monitored included flowering onset, pod production and seed predation. All traits studied responded to shading, exhibiting various levels of plasticity. In particular, dense shade induced a radical but reversible decrease in flower and pod production, while moderate shade had little effect on reproductive traits. The magnitude of the response to dense shade depended on the genotype, showing a genetically based polymorphism of plasticity. The level of plasticity also showed substantial variations between years, and the effect of environmental variations was cumulative over time. This suggests that plasticity can influence the lifetime fitness of U. Europaeus and is involved in the capacity of the species to grow under contrasting environmental conditions. © 2015 Atlan et al.


Ben Abdessalem A.,University of Bordeaux 1 | Azais R.,University of Lorraine | Touzet-Cortina M.,Bordeaux INP | Gegout-Petit A.,University of Lorraine | Puiggali M.,University of Bordeaux 1
Proceedings of the Institution of Mechanical Engineers, Part O: Journal of Risk and Reliability | Year: 2016

Fatigue crack propagation is a stochastic phenomenon due to the inherent uncertainties originating from material properties, environmental conditions and cyclic mechanical loads. Stochastic processes thus offer an appropriate framework for modelling and predicting crack propagation. In this paper, fatigue crack growth is modelled and predicted by a piecewise-deterministic Markov process associated with deterministic crack laws. First, a regime-switching model is used to express the transition between the Paris regime and rapid propagation that occurs before failure. Both regimes of propagation are governed by a deterministic equation whose parameters are randomly selected in a finite state space. This one has been adjusted from real data available in the literature. The crack growth behaviour is well-captured and the transition between both regimes is well-estimated by a critical stress intensity factor range. The second purpose of our investigation deals with the prediction of the fatigue crack path and its variability based on measurements taken at the beginning of the propagation. The results show that our method based on this class of stochastic models associated with an updating method provides a reliable prediction and can be an efficient tool for safety analysis of structures in a large variety of engineering applications. In addition, the proposed strategy requires only little information to be effective and is not time-consuming. © Institution of Mechanical Engineers.


Falleri J.-R.,Bordeaux INP | Reveillere E.G.E.L.,Bordeaux INP
2015 23rd European Signal Processing Conference, EUSIPCO 2015 | Year: 2015

This paper deals with our positive experience about project-based pedagogy with the help of industrial partners to teach signal and image processing. During one semester, students are working in small groups of 6 to 8 students, supervised by two teachers or engineers working in a small or a big com pany. Various topics are proposed each year such as radar pro cessing, mobile communication system or image processing. The role played by the industrial partners is crucial: they give seminars about program management, they evaluate the tech nical quality of the projects and the clarity of the oral presen tation. An award ceremony is also organized at school during which the activities of the companies are presented. There are also some discussions about the activities of a young engineer and several awards in various categories are given. A cocktail party ends up the day. Anonymous online surveys completed by our students as well as discussions with our partners con firm the relevance of these projects. © 2015 EURASIP.


Feng W.,Bordeaux INP | Boukir S.,Bordeaux INP
Proceedings - International Conference on Image Processing, ICIP | Year: 2015

Mislabeled training data is a challenge to face in order to build a robust classifier whether it is an ensemble or not. This work handles the mislabeling problem by exploiting four different ensemble margins for identifying, then eliminating or correcting the mislabeled training data. Our approach is based on class noise ordering and relies on the margin values of misclassified data. The effectiveness of our ordering-based class noise removal and correction methods is demonstrated in performing image classification. A comparative analysis is conducted with respect to the majority vote filter, a reference ensemble-based class noise filter. © 2015 IEEE.


PubMed | Bordeaux INP, CNRS Ecosystems, Biodiversity, and Evolution Laboratory and Laval University
Type: Journal Article | Journal: PloS one | Year: 2015

Phenotypic plasticity may be advantageous for plants to be able to rapidly cope with new and changing environments associated with climate change or during biological invasions. This is especially true for perennial plants, as they may need a longer period to respond genetically to selective pressures than annuals, and also because they are more likely to experience environmental changes during their lifespan. However, few studies have explored the plasticity of the reproductive life history traits of woody perennial species. This study focuses on a woody shrub, Ulex europaeus (common gorse), and on the response of its reproductive traits to one important environmental factor, shading. The study was performed on clones originating from western France (within the native range of this invasive species) and grown for seven years. We compared traits of plants grown in a shade treatment (with two successive shade levels) vs. full natural light. The traits monitored included flowering onset, pod production and seed predation. All traits studied responded to shading, exhibiting various levels of plasticity. In particular, dense shade induced a radical but reversible decrease in flower and pod production, while moderate shade had little effect on reproductive traits. The magnitude of the response to dense shade depended on the genotype, showing a genetically based polymorphism of plasticity. The level of plasticity also showed substantial variations between years, and the effect of environmental variations was cumulative over time. This suggests that plasticity can influence the lifetime fitness of U. Europaeus and is involved in the capacity of the species to grow under contrasting environmental conditions.

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