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  • LPV water delivery canal control based on prescribed order models
    Publication . Caiado, Daniela V.; Lemos, João M.; Igreja, José
    This article addresses the problem of designing an LPV controller for a water delivery canal based on reduced complexity linear models with a priori chosen order. For that sake, by applying a method based on the Laplace transform and the linearization of the Saint-Venant equations, a finite dimensional rational transfer function is obtained for each canal reach. An LPV gain-scheduling controller that relies on H1 optimization is then designed for local upstream canal control. The scheduling variables are the inlet canal flow and the downstream-reach mean level. The uncertainty bound is computed on the basis of the high frequency error of the frequency response of the model used with respect to the one of the infinite-dimensional model by linearizing the Sain-Venant equations. This approach has the advantage of yielding na LPV controller that relies on a model with specified complexity and to relate model uncertainty to physical canal parameters, allowing operation over an extended envelop of water flow and level equilibria.
    2015-07-16Conference object Restricted access Show more
  • Two-loop stability of a complex singlet extended standard model
    Publication . Costa, Raul; Morais, Antonio P.; Sampaio, Marco O. P.; Santos, Rui
    Motivated by the dark matter and the baryon asymmetry problems, we analyze a complex singlet extension of the Standard Model with a Z(2) symmetry (which provides a dark matter candidate). After a detailed two-loop calculation of the renormalization group equations for the new scalar sector, we study the radiative stability of the model up to a high energy scale (with the constraint that the 126 GeV Higgs boson found at the LHC is in the spectrum) and find it requires the existence of a new scalar state mixing with the Higgs with a mass larger than 140 GeV. This bound is not very sensitive to the cutoff scale as long as the latter is larger than 10(10) GeV. We then include all experimental and observational constraints/measurements from collider data, from dark matter direct detection experiments, and from the Planck satellite and in addition force stability at least up to the grand unified theory scale, to find that the lower bound is raised to about 170 GeV, while the dark matter particle must be heavier than about 50 GeV.
    2015-07-16Journal article Restricted access Show more