MATLAB measurement dynamics

For the dynamic lung impedance model to be useable in Finite Difference Method or Finite Element Method impedance signal simulations, the dynamic tissue sample model is discretized into volume data. At first 3D data with 35 x 35 x 35 voxel resolution is prepared from each of the 40 time frames. This allows for easy import into MATLAB or COMSOL based calculation. The volume data includes percentage of blood vessels (blood) for each of the 35 X 35 X 35 X 40 voxels. It can readily be transformed into electric/dielectric properties for each voxel with tissue data available on the internet. But data can also be exported with arbitrary resolution depending on calculation-simulation requirements. The simulations are run separately for each of the 40 time-frames to get full frequency characteristic of impedance measurement across the tissue sample. Finally we can get 40 frequency characteristics—one for each time-frame and to see a dynamic electrical impedance signal on a certain frequency, we just need to plot the impedance value at the chosen frequency from the 40 time-frames. 

The active compensation of the disturbing force Pi can now be achieved by a suitable feedback of the measured base acceleration ai to the input of the high-voltage source for the piezo actuator. Based on a signal flow diagram, which is always to be developed by the designer, for the functionality of the force compensation will be investigated on the computer with support of an appropriate dynamic simulation and analysis software system, for example MATLAB [4]. 

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