Case Report: Giant cystic schwannoma of the middle mediastinum with cervical extension

Schwannomas (neurilemmomas) are benign tumors arising from the Schwann cells of the neural sheath. They are typically, well-encapsulated lesions which rarely adhere to the adjacent structures. In the chest, schwannomas are often seen within the posterior mediastinum and commonly originating along intercostal nerves. Several operative approaches have previously been described for the resection of these tumors, including thoracoscopic techniques and posterolateral thoracotomy. We report in this case a giant cystic mediastinal schwannoma of the left recurrent laryngeal nerve with cervical extension, unresectable by the usual described approaches, which was completely removed through a cervical approach.Keywords: mediastinal tumor; schwannoma; thoracotomy; cervicotom

On-line estimation of the reaction rates in bioreactors from multirate sampled outputs with multiple delays

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Adaptive fuzzy system-based variable-structure controller for multivariable nonaffine nonlinear uncertain systems subject to actuator nonlinearities

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A cascade predictor for nonlinear systems with a constant output delay

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A filtered high gain observer for a class of non uniformly observable systems – Application to a phytoplanktonic growth model

International audienceThe design of a high gain observer with filtering capabilities for a class of non uniformly observable systems is proposed. The filtering feature enables to perform a smooth estimation in the presence of noisy output measurements. Of fundamental interest, the Filtered High Gain Observer (FHGO) design is first carried out by assuming that the output measurements are available in a continuous manner before being extended to the case of sampled outputs leading thereby to a continuous-discrete time FHGO which inherits the main properties of the original FHGO. The performance of the FHGO and its main properties are highlighted and compared to those of a Standard High Gain Observer (SHGO) through a bioprocess dealing with the growth of a phytoplanktonic population

Improved high gain observer design for a class of disturbed nonlinear systems

International audienceAbstract This paper provides a redesigned version of the Standard High Gain Observer (SHGO) to cope with the peaking phenomenon occurring during the transient periods as well as the sensitivity to high frequency measurement noise. The observer design is performed for a class of uniformly observable systems with noise free as well as noisy output measurements and the resulting observer is referred to as Non Peaking Filtered High Gain Observer (NPFHGO). The NPFHGO shares the same structure as its underlying SHGO and differs only by its corrective term which is still parameterized by a unique positive scalar up to an appropriate expression involving nested saturations. Of a fundamental interest, the power of the scalar parameter does not exceed one unlike in the case of the SHGO where this power grows from 1 to the system dimension. Moreover, it is shown that the equations of the NPFHGO become identical to those of the SHGO after a transient time horizon that can made arbitrarily small for sufficiently high values of the design parameter. A particular emphasis is put on the case of systems with noisy output measurements. It is shown how a multiple integrator of the corrupted outputs can be cascaded with the original system leading to an augmented system included in the class of systems for which the NPFHGO has been designed. The performance and main properties of the NPFHGO are highlighted and compared to those of its underlying SHGO through simulation results involving a single link robot arm system

A new filtered high gain observer design for the estimation of the components concentrations in a photobioreactor in microalgae culture

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On-line estimation of the reaction rates from sampled measurements in bioreactors

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Observer design for a class of uncertain systems with delayed outputs

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