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njit-etd2003-081 - New Jersey Institute of Technology

njit-etd2003-081 - New Jersey Institute of Technology

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1 0<br />

1. Present the application <strong>of</strong> time-frequency analysis as an innovative approach to better<br />

represent the biological signals, namely HRV, BP and respiration on normal and COPD<br />

subjects. Four different time-frequency representations (Short-time Fourier Transform,<br />

the smoothed-pseudo Wigner, the Choi-William and the Born-Jordan-Cohen) and<br />

wavelet distribution are applied on modeled HRV test and experimental signals taken<br />

from COPD and normal subjects.<br />

2. Compare the best Cohen class time-frequency representation to the wavelet<br />

distribution to see which representation overcomes the drawbacks <strong>of</strong> others by providing<br />

higher resolution in time and frequency while suppressing interferences between the<br />

signal components. Use these 2 distributions (one from the Cohen class and the wavelet<br />

distribution) to investigate the degradation <strong>of</strong> health from a change in activity <strong>of</strong> the<br />

autonomic nervous system (ANS) due to the COPD condition as reflected in the HRV<br />

signal. By expanding the concept <strong>of</strong> spectral analysis <strong>of</strong> HRV into time-frequency<br />

analysis, it is possible to quantitatively assess the parasympathetic (HF) and sympathovagal<br />

balance (LF:HF) changes as a function <strong>of</strong> time. As a result, the assessment <strong>of</strong> the<br />

ANS during rapid changes is made.<br />

3. Analyze HRV and physiological signals using coherence and partial coherence to<br />

look at their inter-relationship as a whole or just residual components with the effect <strong>of</strong><br />

the third component removed. This combination <strong>of</strong> techniques allows researchers to<br />

have unique opportunities to examine the vagal and sympatho-vagal systems.<br />

4. A general class <strong>of</strong> Exogenous Input AutoRegressive (ARX) model is developed for<br />

the cardiovascular system using system identification techniques as an analytical tool for<br />

uncovering the hidden autonomic control processes in order to explain the physiological

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