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Percorrer por autor "Ionescu, Clara"

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  • Mechanical properties and impedance model for the branching network of the sapping system in the leaf of Hydrangea Macrophylla
    Publication . Ionescu, Clara; Tenreiro Machado, J. A.
    An electrical analogue model has been developed based on main leaf hydraulics characteristics and intrinsic geometry. The simulations show good qualitative agreements with specialized literature reports. The constant-phase behavior and the variation with ambient temperature of the frequency response of the leaf impedance are assessed by means of simulation studies.
    2010-04Artigo científico Acesso restrito Ver mais
  • Nonlinear dynamics of the patient’s response to drug effect during general anesthesia
    Publication . Machado, J. A. Tenreiro; Ionescu, Clara; Keyser, Robin De; Decruyenaere, Johan; Struys, Michel M.R.F.
    In today’s healthcare paradigm, optimal sedation during anesthesia plays an important role both in patient welfare and in the socio-economic context. For the closed-loop control of general anesthesia, two drugs have proven to have stable, rapid onset times: propofol and remifentanil. These drugs are related to their effect in the bispectral index, a measure of EEG signal. In this paper wavelet time–frequency analysis is used to extract useful information from the clinical signals, since they are time-varying and mark important changes in patient’s response to drug dose. Model based predictive control algorithms are employed to regulate the depth of sedation by manipulating these two drugs. The results of identification from real data and the simulation of the closed loop control performance suggest that the proposed approach can bring an improvement of 9% in overall robustness and may be suitable for clinical practice.
    2014Artigo científico Acesso aberto Ver mais
  • Special Issue: Advances in Fractional Dynamics and Control
    Publication . Ionescu, Clara; Zhou, Yong; Tenreiro Machado, J. A.
    Since the end of the 17th century a considerable number of important mathematicians contributed to the development of the Fractional Calculus (FC). More recently, in the last decades of the 20th century, it has been found that the dynamical behavior of many complex systems can be properly described by fractional order models. Due to the extensive applications of FC tools in engineering and science, research in this area has grown significantly all over the world
    2016Artigo científico Acesso restrito Ver mais