Isabelle Queinnec

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This paper addresses the problem of controlling a certain class of continuous-time nonlinear systems subject to actuator saturations. The design of state feedback gains is done by considering a modelling of the nonlinear saturated system through deadzone nonlinearities satisfying a modified sector condition, which encompasses the classical(More)
This paper addresses the control design problem for a certain class of continuous-time nonlinear systems subject to actuator saturations. The system under consideration consists of a system with two nested nonlinearities of different type: saturation nonlinearity and cone-bounded nonlinearity. The control law investigated for stabilization purposes depends(More)
This work presents an analytical study and an experimental verification of a robust control design based on a linear matrix inequalities (LMI) framework for boost regulators. With the proposed LMI method, nonlinearities and uncertainties are modelled as a convex polytope. Thus, the LMI constraints permit to robustly guarantee a certain perturbation(More)
This paper deals with the problem of stabilizing a bilinear system with unstable open-loop part by means of state feedback control. The implicit objective is to provide an estimate of the region of stability of the closed-loop system. The proposed procedure can be decomposed into two convex optimization problems described in terms of LMIs: i) Given a(More)
This genome-scale study analysed the various parameters influencing protein levels in cells. To achieve this goal, the model bacterium Lactococcus lactis was grown at steady state in continuous cultures at different growth rates, and proteomic and transcriptomic data were thoroughly compared. Ratios of mRNA to protein were highly variable among proteins but(More)
Phenol biodegradation by Ralstonia eutropha was modeled in different culture modes to assess phenol feeding in biotechnological depollution processes. The substrate-inhibited growth of R. eutropha was described by the Haldane equation with a Ks of 2 mg/L, a Ki of 350 mg/L and a mumax of 0.41 h(-1). Furthermore, growth in several culture modes was(More)
Bacterial adaptation involves extensive cellular reorganization. In particular, growth rate adjustments are associated with substantial modifications of gene expression and mRNA abundance. In this work we aimed to assess the role of mRNA degradation during such variations. A genome-wide transcriptomic-based method was used to determine mRNA half-lives. The(More)
This paper addresses the problem of stability analysis for a given class of nonlinear systems resulting from the connection of a linear systemwith an isolated backlash operator. Constructive conditions based on LMIs to ensure closed-loop stability are proposed by using some suitable Lyapunov functionals with quadratic terms and Lure type terms, and(More)
To remove ammonia for production of drinking water, nitrification can be performed in a bio-filter. At least 1 month is necessary to capture from the groundwater and then grow a sufficient amount of nitrifying bacteria to reach the desired removal efficiency. Improving start-up of bio-filters at low substrate concentration is therefore a major challenge. In(More)
A consistent framework for robust linear quadratic regulators (LQRs) control of power converters is presented. Systems with conventional LQR controllers present good stability properties and are optimal with respect to a certain performance index. However, LQR control does not assure robust stability when the system is highly uncertain. In this paper, a(More)