Generalized transfer function of nonlinear active semiconductor microring resonators

2006 ◽  
Author(s):  
Yann G. Boucher ◽  
Yannick Dumeige ◽  
Laura Ghisa ◽  
Patrice Féron
Keyword(s):  
Transfer Function ◽  
Microring Resonators ◽  
Generalized Transfer Function

Multiscale mathematical modeling vs. the generalized transfer function approach for aortic pressure estimation: a comparison with invasive data

2018 ◽  
Vol 42 (5) ◽  
pp. 690-698 ◽  
Author(s):  
Andrea Guala ◽  
Francesco Tosello ◽  
Dario Leone ◽  
Luca Sabia ◽  
Fabrizio D’Ascenzo ◽  
...  
Keyword(s):  
Mathematical Modeling ◽  
Transfer Function ◽  
Aortic Pressure ◽  
Function Approach ◽  
Pressure Estimation ◽  
Generalized Transfer Function

Blood Flow Modeling to Improve Cardiovascular Diagnostics: Application of A GTF to Predict Central Aortic Pressure using a 1-D Model

2018 ◽  
Vol 7 (4.26) ◽  
pp. 146
Author(s):  
A. T. Butt ◽  
Y. A. Abakr ◽  
K. B. Mustapha
Keyword(s):  
Transfer Function ◽  
Transfer Functions ◽  
Experimental Studies ◽  
Aortic Pressure ◽  
Iliac Arteries ◽  
Central Aortic Pressure ◽  
Blood Flow Modeling ◽  
Feasible Alternative ◽  
Generalized Transfer Function ◽  
Mean Square Errors

This study aims to demonstrate that a comprehensive one-dimensional model of the arterial network can be used in conjunction with the generalized transfer function (GTF) technique to estimate central aortic pressure using pressure waveforms obtained from peripheral sites. The peripheral and central pressure waveforms for a healthy subject are used to estimate transfer functions, which are then used to reconstruct central aortic pressure waveforms for a second model that simulates arterial stiffening. The similarities between the simulated aortic waveform and the waveforms estimated using the transfer function are and   from the brachial, carotid and iliac arteries, respectively. The root-mean-square errors (RMSE) for the reconstructed waveforms from the brachial, carotid and iliac arteries are and  mmHg, respectively. The results from this study illustrate that the proposed method provides a feasible alternative to higher dimensional models as well as experimental studies and can greatly enhance the accuracy of central aortic pressure estimation.     

Effect of non-invasive calibration of radial waveforms on error in transfer-function-derived central aortic waveform characteristics

2004 ◽  
Vol 107 (2) ◽  
pp. 205-211 ◽  
Author(s):  
Sarah A. HOPE ◽  
Ian T. MEREDITH ◽  
James D. CAMERON
Keyword(s):  
Transfer Function ◽  
Augmentation Index ◽  
Systolic Pressure ◽  
Function Estimation ◽  
Non Invasive ◽  
Clinical Interest ◽  
Time Parameters ◽  
Generalized Transfer Function ◽  
The Impact ◽  
Significant Underestimation

Transfer function techniques are increasingly used for non-invasive estimation of central aortic waveform characteristics. Non-invasive radial waveforms must be calibrated for this purpose. Most validation studies have used invasive pressures for calibration, with little data on the impact of non-invasive calibration on transfer-function-derived aortic waveform characteristics. In the present study, simultaneous invasive central aortic (Millar Mikro-tip® catheter transducer) and non-invasive radial (Millar® Mikro-tip® tonometer) pressure waveforms and non-invasive brachial pressures (Dinamap®) were measured in 42 subjects. In this cohort, radial waveforms were calibrated to both invasive and non-invasive mean and diastolic pressures. From each of these, central waveforms were reconstructed using a generalized transfer function obtained by us from a previous cohort [Hope, Tay, Meredith and Cameron (2002) Am. J. Physiol. Heart Circ. Physiol. 283, H1150–H1156]. Waveforms were analysed for parameters of potential clinical interest. For calibrated radial and reconstructed central waveforms, different methods of calibration were associated with differences in pressure (P<0.001), but not time parameters or augmentation index. Whereas invasive calibration resulted in little error in transfer function estimation of central systolic pressure (difference −1±8 mmHg; P=not significant), non-invasive calibration resulted in significant underestimation (7±12 mmHg; P<0.001). Errors in estimated aortic parameters differed with non-invasively calibrated untransformed radial and transfer-function-derived aortic waveforms (all P<0.01), with smaller absolute errors with untransformed radial waveforms for most pressure parameters [systolic pressure, 5±16 and 7±12 mmHg; pulse pressure, 0±16 and 4±12 mmHg (radial and derived aortic respectively)]. When only non-invasive pressures are accessible, analysis of untransformed radial waveforms apparently produces smaller errors in the estimation of central aortic systolic pressure, and other waveform parameters, than using a generalized transfer function.

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