21 research outputs found

    Cross standard form : a solution to improve a given controller with H2 or Hoo specifications

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    This paper introduces in cross standard form (CSF) as a solution to the inverse optimal control problem. That is, the CSF is a canonical standard problem whose unique H1 or H2 optimal controller is a given controller. From the control design point of view, the general idea is to apply the CSF to a given controller in order to set up a standard problem which can be completed to handle frequency domain H2 or H1 specification. The analytical formulation of the CSF proposed in this paper can be applied to reduced-, full- or augmented-order compensators or two-degree of freedom compensations. Numerical and academic examples are given

    Mixed H2/Hinfty Control Design for Mechanical Systems: Analytical and Numerical Developments

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    Picosecond observation of cation-stepwise delayed and cation-triggered photoinduced intramolecular charge transfer in fluorescent cation probes

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    International audienceTime-resolved transient absorption and gain spectra with subpicosecond laser excitation are reported for donor-donor and acceptor-donor stilbene-crowns (in each compound the electron donor group is the 15-aza-5-crown macrocycle, D1). The effect of the calcium cation on the photoinduced intramolecular charge transfer (ICT) rate constants are measured. When the cation is on the donor side of the molecular system (class 1: D1CS-Crown), the photoinduced ICT process is slowed down and goes through several intermediates characterized by a distancing of the cation, while a solvent molecule enters its coordination sphere. When the cation is on the acceptor side (class 2: D1DS-Crown,D1DB-Crown and D1DCS-Crown), the photoinduced ICT process becomes too fast to be measured, even on the picosecond scale

    Cation-triggered photoinduced intramolecular charge transfer and fluorescence red-shift in fluorescence probes

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    We report the synthesis of two new nonpolar fluorescence cation probes (DDS-crown, 5 and DDB-crown, 6) designed from stilbene and 1,4-diphenyl 1,3-butadiene, respectively, by substitution at the two ends with two electron-donor groups (D) (dimethylamino and monoaza-15-crown-5), one of which is able to chelate a cation. The absorption and fluorescence spectra in several solvents of different polarity and the picosecond transient absorption spectra give an estimate of the Intramolecular Charge Transfer (ICT) strength in the excited state. When a cation (Ca2+) is chelated by the macrocycle, the ICT process is increased and the fluorescence is red-shifted. These spectroscopic effects of cation-chelation are enhanced in a third probe (DDCS-crown, 7) derived from DDS-crown by inserting an electron-acceptor (A) group (CN) at the ortho position of the macrocycle in order to increase the ICT

    Algorithms for the Automatic Identification of MARFEs and UFOs in JET Database of Visible Camera Videos

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    MARFE instabilities and UFOs leave clear signatures in JET fast visible camera videos. Given the potential harmful consequences of these events, particularly as triggers of disruptions, it would be important to have the means of detecting them automatically. In this paper, the results of various algorithms to identify automatically the MARFEs and UFOs in JET visible videos are reported. The objective is to retrieve the videos, which have captured these events, exploring the whole JET database of images, as a preliminary step to the development of real-time identifiers in the future. For the detection of MARFEs, a complete identifier has been finalized, using morphological operators and Hu moments. The final algorithm manages to identify the videos with MARFEs with a success rate exceeding 80%. Due to the lack of a complete statistics of examples, the UFO identifier is less developed, but a preliminary code can detect UFOs quite reliably

    Producing onion seeds for organic agriculture

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    This tool is a data sheet that can be used by French farmers who produce or want to produce onion seeds in organic conditions. It provides advice starting from the contract signing to the seed drying, going through the specificities of the crop, the sowing, irrigation, specific pests and their management, and the harvest
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