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Modeling of the lung impedance using a fractional order ladder network with constant phase elements
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Orientador(es)
Resumo(s)
The self similar branching arrangement of the airways
makes the respiratory system an ideal candidate for the
application of fractional calculus theory. The fractal geometry
is typically characterized by a recurrent structure. This study
investigates the identification of a model for the respiratory tree by
means of its electrical equivalent based on intrinsic morphology.
Measurements were obtained from seven volunteers, in terms of
their respiratory impedance by means of its complex representation
for frequencies below 5 Hz. A parametric modeling is then
applied to the complex valued data points. Since at low-frequency
range the inertance is negligible, each airway branch is modeled
by using gamma cell resistance and capacitance, the latter having a
fractional-order constant phase element (CPE), which is identified
from measurements. In addition, the complex impedance is also
approximated by means of a model consisting of a lumped series
resistance and a lumped fractional-order capacitance. The results
reveal that both models characterize the data well, whereas the
averaged CPE values are supraunitary and subunitary for the
ladder network and the lumped model, respectively.
Descrição
Palavras-chave
Constant phase element (CPE) Forced oscillations Fractal structure Frequency response Ladder network Respiratory impedance
Contexto Educativo
Citação
Editora
IEEE