Recent advances in engineering applications of chaos include multimedia security, disturbance modeling in power systems and performance enhancement of electronic circuits among others
Simple MOS transistor-based realization of fractional-order capacitors
A new second-order MOS transistor based circuit block approximating the behavior of a fractional-order capacitor is proposed
Review of the missing mechanical element: Memdamper
In this paper, the analogy between electrical and mechanical quantities is reviewed
On the realization of Current-Mode Fractional-order Simulated Inductors
The objective of this work is to revisit the design criteria of current-mode simulated inductors in order to realize their fractional-order versions
Log-domain implementation of fractional-order element emulators
Novel fractional-order capacitor and inductor em-ulators are presented in this work, which offer fully electronic tunability of their characteristics and, simultaneously, reduced circuit complexity compared to those already introduced in the literature
Design equations for fractional-order sinusoidal oscillators: Practical circuit examples
Some practical sinusoidal oscillators are studied in the general form where fractional-order energy storage elements are considered
Modeling woody plant tissue using different fractional-order circuits
This chapter presents results on the most suitable bio-impedance circuits for modeling woody plants. The modified double-shell, the modified triple Cole-Cole, and the traditional wood circuit models are compared for fitting experimentally measured data. Consequently, a modified circuit model is proposed. This model gives the best results for all interelectrode spacing distances when compared to the other circuits. All impedance data have been measured using the research-grade SP150 electrochemical station in the frequency range 0.1 Hz to 200 kHz. The fitting is done using the Zfit of the impedance analyzer SP150. © 2022 Elsevier Inc. All rights reserved.
Fractional-order oscillators
Fractional-order calculus is the branch of mathematics which deals with non-integerorder differentiation and integration. Fractional calculus has recently found its way to engineering applications; particularly electronic circuits with promising results showing the feasibility of fabricating fractional-order capacitors on silicon. Fractionalorder capacitors are lossy non-deal capacitors with an impedance given by Zc = (1/j?C)?, where C is the pseudo-capacitance and ? is its order (0 < ? ? 1). When these fractional-order capacitors are employed within an oscillator (sinusoidal or relaxation) circuit, this oscillator is called a fractional-order oscillator and is described by non-integer-order differential equations. Therefore, an oscillator of order 1.5 or 2.6 is possible to obtain. While the oscillation frequency in integer-order oscillators is related to their RC time constants, fractional-order oscillators have their oscillation frequencies also related to ?. This adds more design freedom and enables extremely high or extremely low oscillation frequencies even with large RC time constants. This chapter aims at reviewing the theory of designing fractional-order oscillators accompanied by several design examples. Experimental results are also shown. © The Institution of Engineering and Technology 2017. All rights reserved.
Plant Tissue Modelling Using Power-Law Filters
Impedance spectroscopy has became an essential non-invasive tool for quality assessment measurements of the biochemical and biophysical changes in plant tissues. The electrical behaviour of biological tissues can be captured by fitting its bio-impedance data to a suitable circuit model. This paper investigates the use of power-law filters in circuit modelling of bio-impedance. The proposed models are fitted to experimental data obtained from eight different fruit types using a meta-heuristic optimization method (the Water Cycle Algorithm (WCA)). Impedance measurements are obtained using a Biologic SP150 electrochemical station, and the percentage error between the actual impedance and the fitted models’ impedance are reported. It is found that a circuit model consisting of a combination of two second-order power-law low-pass filters shows the least fitting error. © 2022 by the authors.
Numerical Sensitivity Analysis and Hardware Verification of a Transiently-Chaotic Attractor
We introduce a new chaotic system with nonhyperbolic equilibrium and study its sensitivity to different numerical integration techniques prior to implementing it on an FPGA. We show that the discretization method used in numerically integrating the set of differential equations in MATLAB and Mathematica does not yield chaotic behavior except when a low accuracy Euler method is used. More accurate higher-order numerical algorithms (such as midpoint and fourth-order Runge-Kutta) result in divergence in both MATLAB and Mathematica (but not Python), which agrees with the divergence observed in an analog circuit implementation of the system. However, a fixed-point digital FPGA implementation confirms the chaotic behavior of the system using Euler and fourth-order Runge-Kutta realizations. Therefore, the increased sensitivity of chaotic systems with nonhyperbolic equilibrium should be carefully considered for reproducibility. © 2022 World Scientific Publishing Company.