Do the Bio-impedance Models Exhibit Pinched Hysteresis?

Recently, pinched hysteresis has been found in the electrical modelling of regular plant tissues. Usually, the biological tissues are characterized in the frequency domain using bio-impedance analyzers without investigating the time domain, which would show the pinched hysteresis. In this paper, the current-voltage analysis of some of the widely known electrical bio-impedance models is studied. The investigated models are the single dispersion Cole-impedance model, the double dispersion Cole-impedance model and the fractional-order simplified Hayden model to prove that these models can not exhibit pinched hysteresis. It is proved mathematically in this paper that there are no pinch-off points that would exist in these models. These results are verified with numerical simulations of three different plants: tomato, carrot and banana, concluding that the bioimpedance modelling needs a nonlinear element to model the pinched hysteresis in the current-voltage behaviour of these tissues. © 2020 IEEE.

Comparison of Different Implementation Methods of Fractional-Order Derivative/Integral

Implementing a fractional-order operator requires many resources to acquire an accurate response compared to the theoretical response. In this paper, three implementation methods of digital fractional-order operators are exploited. The three implementation methods are based on FIR, IIR, and lattice wave digital filters. The three methods are implemented using different optimization algorithms to optimize the choice of the coefficients of the three filters. This optimization is done to approximate the frequency response of an ideal fractional operator. This comparison aims to determine each implementation method’s accuracy and resource usage level to decide which method is better for different systems. © 2021 IEEE.

Toward Portable Bio-impedance devices

Bio-impedance measurement has been used as an indicator for specific physical and chemical changes in food products, fruits and vegetables, cancer detection and other applications. In this paper, a portable wireless bio-impedance measurement embedded system, based on the AD5933 chip, is introduced. The system is calibrated using a parallel RC network and the industry standard electrochemical station BioLogic SP-150. The module can be used in many impedance measuring applications. © 2019 IEEE.