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Advisor(s)
Abstract(s)
This paper presents the measurement, frequency-response modeling and identification,
and the corresponding impulse time response of the human respiratory impedance and
admittance. The investigated adult patient groups were healthy, diagnosed with chronic
obstructive pulmonary disease and kyphoscoliosis, respectively. The investigated children
patient groups were healthy, diagnosed with asthma and cystic fibrosis, respectively.
Fractional order (FO) models are identified on the measured impedance to quantify
the respiratory mechanical properties. Two methods are presented for obtaining and
simulating the time-domain impulse response from FO models of the respiratory
admittance: (i) the classical pole-zero interpolation proposed by Oustaloup in the early 90s,
and (ii) the inverse discrete Fourier Transform (DFT). The results of the identified FO models
for the respiratory admittance are presented by means of their average values for each
group of patients. Consequently, the impulse time response calculated from the frequency
response of the averaged FO models is given by means of the two methods mentioned
above. Our results indicate that both methods provide similar impulse response data.
However, we suggest that the inverse DFT is a more suitable alternative to the high order
transfer functions obtained using the classical Oustaloup filter. Additionally, a power law
model is fitted on the impulse response data, emphasizing the intrinsic fractal dynamics of
the respiratory system.
Description
Keywords
Respiratory mechanics Fractional order Frequency response Impulse response Fourier transform Admittance
Citation
Publisher
Elsevier