A parametric insensitive H2 control design approach

H₂ and H_∞ control design methodologies are known to be efficient to deal with multivariable control problems. However, most of them do not take explicitly the parametric uncertainties into account. This paper proposes a low parametric sensitivity H₂ control design method as an alternative to µ‐synthesis or robust H₂ control design. In addition to the standard H₂ criterion, the H₂ norm of the parametric sensitivity function is introduced in order to improve the robustness of the resulting controller. Unfortunately, this problem is a difficult one. Its equivalence to structured feedback H₂ control problem will be shown. The underlying BMI will be solved by making use of an iterative LMI procedure. Two examples will illustrate the interest of the approach. Copyright © 2004 John Wiley & Sons, Ltd.     

Study of thermal and acoustic noise interferences in low stiffness atomic force microscope cantilevers and characterization of their dynamic properties

The atomic force microscope (AFM) is a powerful tool for the measurement of forces at the micro/nano scale when calibrated cantilevers are used. Besides many existing calibration techniques, the thermal calibration is one of the simplest and fastest methods for the dynamic characterization of an AFM cantilever. This method is efficient provided that the Brownian motion (thermal noise) is the most important source of excitation during the calibration process. Otherwise, the value of spring constant is underestimated. This paper investigates noise interference ranges in low stiffness AFM cantilevers taking into account thermal fluctuations and acoustic pressures as two main sources of noise. As a result, a preliminary knowledge about the conditions in which thermal fluctuations and acoustic pressures have closely the same effect on the AFM cantilever (noise interference) is provided with both theoretical and experimental arguments. Consequently, beyond the noise interference range, commercial low stiffness AFM cantilevers are calibrated in two ways: using the thermal noise (in a wide temperature range) and acoustic pressures generated by a loudspeaker. We then demonstrate that acoustic noises can also be used for an efficient characterization and calibration of low stiffness AFM cantilevers. The accuracy of the acoustic characterization is evaluated by comparison with results from the thermal calibration.     

Model-based cloud resource management with TOSCA and OCCI

Software and Systems Modeling - With the advent of cloud computing, different cloud providers with heterogeneous cloud services (compute, storage, network, applications, etc.) and their related...     

Mechanical properties of continuous bamboo fiber-reinforced biobased polyamide 11 composites

This study is devoted to the analysis of the properties of continuous bamboo fiber (BF)-reinforced polyamide 11 (PA 11) composites. The SEM observations highlighted continuity between BFs and the polymeric matrix showing a high density of hydrogen bonds. The comparative calorimetric study of the matrix and its composites showed that the crystallinity of PA 11 was not modified by the presence of bamboo fibers. The physical aging observed in PA 11 is no more observed in composites due to physical interactions between PA 11 and BFs. The mechanical properties were investigated by tensile strength and dynamic mechanical analysis. The introduction of BFs enhanced Young's modulus of the matrix by a factor of 10. The presence of BFs also improved the storage shear modulus G′ over the whole temperature range. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47623.     

Line of sight controller tuning using Bayesian optimisation: application to a double stage stabilisation platform

The inertial stabilisation of the line of sight of an imager fixed on a mobile carrier is considered in order to acquire good quality images despite the disturbances generated by the carrier. A double stage mechanical stabilisation architecture is proposed, where a second stabilisation stage, based on a piezoelectric actuator, is added to the usual structure. The piezoelectric actuator transfer function and hysteresis are characterised through experiments. In order to design the controllers of both stages, a high-level image quality criterion (the modulation transfer function (MTF)) is considered, together with design constraints on the main variables of interest. The criterion and the constraints are evaluated by realistic simulations based on some input and noise profiles measured on a real-life system. The MTF evaluation being time-consuming, a Bayesian optimisation method specially dedicated to expensive-to-evaluate functions is used to obtain the parameters of the controllers. The obtain experimental results are displayed and their performances discussed.     

Gastric Cancer: Advances in Carcinogenesis Research and New Therapeutic Strategies

Gastric cancer’s bad incidence, prognosis, cellular and molecular heterogeneity amongst others make this disease a major health issue worldwide. Understanding this affliction is a priority for proper patients’ management and for the development of efficient therapeutical strategies. This review gives an overview of major scientific advances, made during the past 5-years, to improve the comprehension of gastric adenocarcinoma. A focus was made on the different actors of gastric carcinogenesis, including, Helicobacter pylori cancer stem cells, tumour microenvironment and microbiota. New and recent potential biomarkers were assessed as well as emerging therapeutical strategies involving cancer stem cells targeting as well as immunotherapy. Finally, recent experimental models to study this highly complex disease were discussed, highlighting the importance of gastric cancer understanding in the hard-fought struggle against cancer relapse, metastasis and bad prognosis.     

Flexibility and binding affinity in protein–ligand,protein–protein and multi-component protein interactions: limitations of current computational approaches

The recognition process between a protein and a partner represents a significant theoretical challenge. In silico structure-based drug design carried out with nothing more than the three-dimensional structure of the protein has led to the introduction of many compounds into clinical trials and numerous drug approvals. Central to guiding the discovery process is to recognize active among non-active compounds. While large-scale computer simulations of compounds taken from a library (virtual screening) or designed de novo are highly desirable in the post-genomic area, many technical problems remain to be adequately addressed. This article presents an overview and discusses the limits of current computational methods for predicting the correct binding pose and accurate binding affinity. It also presents the performances of the most popular algorithms for exploring binary and multi-body protein interactions.     

A Robust Transferable Method for the Determination of Glyphosate Residue in Liver After Derivatization by Ultra-high Pressure Liquid Chromatography–Tandem Mass Spectrometry

Glyphosate determination in liver is challenging due to this particular molecule/matrix combination. Glyphosate is a very polar molecule and liver composition is highly variable between individuals and species. Since 2014, the Multiannual Control Program (MACP) of the European Union (EU) demands to analyse glyphosate in food of animal origin on a voluntary basis. Moreover, this analysis will be mandatory in 2017. This paper describes a robust and easily transferable method for glyphosate quantification in liver of animal origin by means of liquid chromatography–tandem mass spectrometry (LC-MS/MS). An intensive clean-up was used to eliminate matrix interferences and was combined with a derivatization step which ensures good retention of glyphosate on a conventional reverse-phase LC column. This method allows to meet the MACP requirements without a time-consuming change in the set-up of the routinely used LC-MS/MS system. Furthermore, it allows the use of an LC column and mobile phases often used in multi-residue analysis. The analytical method was validated according to the SANCO/12571/2013 criteria. Isotopic dilution was used to quantify glyphosate, leading to mean apparent recoveries of 115 and 101 % for the low (0.025 mg kg^?1) and the high (0.250 mg kg^?1) fortification levels, respectively. At both levels, the relative standard deviation was below 10 %. The limit of quantification of 0.025 mg kg^?1 was found to be satisfactory as it was below the maximum residue level (MRL) value set at 0.050 mg kg^?1 for glyphosate in liver. It is also the lowest MRL for all commodity types.     

Thermal Resonance at the Microscale in AC Scanning Thermal Microscopy with a Thermal-Resistive Probe

Investigation of the thermal-resistive probe response in an AC scanning thermal microscope (SThM) as a function of the distance probe–material surface under ambient conditions and the current excitation frequency is presented. The analysis of temperature experimental results points out a phenomenon which can be interpreted as a thermal wave resonance. The modeling of the thermal response with the finite element method considering the surrounding medium as a thermally conducting medium tends to confirm this. This phenomenon is independent of the sample nature and is related to the thermal diffusion length of the air medium between the probe and the sample. An equivalent resonance factor is defined: it shows a linear dependence with the characteristic distance for which the thermal resonance phenomenon is an extremum. The system—probe/sample surface—behaves as a resonant cavity at the microscale. This configuration is not specific to a SThM and can occur within electronic devices.