Biomedical Engineering Reference
In-Depth Information
Fig. 5.16
The complex
impedance by means of its
real (
top
) and imaginary
(
bottom
) parts measured from
the 10 volunteers at low
frequencies. Each frequency
point is depicted by its mean
value, distribution, and
confidence intervals. Crosses
denote outliers defined as 1.5
times further than the mean
value
observed also in the slim (s) and the tall (t) subjects, but in order to quantify the
relation of the ladder network structure with weight and height, more measurements
are necessary. When validating with external data and population data, it is impor-
tant to notice that the phase-locking effect takes place in frequencies lower than the
standard clinical range of tested frequencies.
The results of the identification are plotted in Figs.
5.18
,
5.19
,
5.20
,
5.21
and
5.22
. The good results support the claim that when modeling the respiratory system
with lumped parametric models, the use of FO terms is justified by the intrinsic
structure of the respiratory tree. The fact that this augmented ladder network model
comprising the full recurrent ladder network was able to capture the impedance
is an indication that FO models are therefore natural solutions for a parsimonious
modeling approach.
5.4 Summarizing Thoughts
Based on the results presented in this chapter, one may speculate that the proposed
model can be successfully used for characterization of the intrinsic fractal geometry
and its implicit properties: self-similarity and recurrence.
For the symmetric tree representation, we have established the following:
