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FPGA realization of a speech encryption system based on a generalized modified chaotic transition map and bit permutation

This paper proposes a generalized modified chaotic transition map with three independent parameters. A hardware speech encryption scheme utilizing this map along with a bit permutation network is presented. While the transition map’s generalization introduces additional parameters, the modification enhances its chaotic properties and overcomes the finite range of the control parameter and dynamical degradation problems. The modification also presents a simplification for the hardware realization of the exponentiation operation in the map’s equation because the modified output range allows

Circuit Theory and Applications
Software and Communications

Parallel feedback compensation for LDO voltage regulators

A novel low dropout (LDO) voltage regulator compensation technique is demonstrated. A parallel feedback path is used to insert a zero at approximately three times the output pole. The parallel feedback consists of passive elements only and occupies small area. The proposed technique completely eliminates the output pole at different load conditions and results in high LDO bandwidth, which achieves fast output tracking of the input reference and fast recovery of sudden load changes. Moreover, the output pole elimination at different load conditions enables the potential scaling of the error

Circuit Theory and Applications
Software and Communications

Multi-phase oscillator for higher-order PSK applications

Multi-phase oscillator is an essential block in digital communication systems especially phase shift keying PSK based systems. In this paper, a procedure for designing a multi-phase oscillator with any required phase shift is proposed, unlike the previous oscillator which generates equal phase shifts. This oscillator circuit is built using fractional-order elements to generate any distribution of phase shift. The general characteristics equation is studied where the condition for oscillation and oscillation frequency are derived. Finally, different examples are introduced with their

Circuit Theory and Applications
Software and Communications

Reevaluation of Performance of Electric Double-layer Capacitors from Constant-current Charge/Discharge and Cyclic Voltammetry

The electric characteristics of electric-double layer capacitors (EDLCs) are determined by their capacitance which is usually measured in the time domain from constant-current charging/discharging and cyclic voltammetry tests, and from the frequency domain using nonlinear least-squares fitting of spectral impedance. The time-voltage and current-voltage profiles from the first two techniques are commonly treated by assuming ideal S s C behavior in spite of the nonlinear response of the device, which in turn provides inaccurate values for its characteristic metrics. In this paper we revisit the

Circuit Theory and Applications
Software and Communications

Finite precision logistic map between computational efficiency and accuracy with encryption applications

Chaotic systems appear in many applications such as pseudo-random number generation, text encryption, and secure image transfer. Numerical solutions of these systems using digital software or hardware inevitably deviate from the expected analytical solutions. Chaotic orbits produced using finite precision systems do not exhibit the infinite period expected under the assumptions of infinite simulation time and precision. In this paper, digital implementation of the generalized logisticmap with signed parameter is considered. We present a fixed-point hardware realization of a Pseudo-Random

Circuit Theory and Applications
Software and Communications

Chaotic properties of various types of hidden attractors in integer and fractional order domains

Nonlinear dynamical systems with chaotic attractors have many engineering applications such as dynamical models or pseudo-random number generators. Discovering systems with hidden attractors has recently received considerable attention because they can lead to unexpected responses to perturbations. In this chapter, several recent examples of hidden attractors, which are classified into several categories from two different viewpoints, are reviewed. From the viewpoint of the equilibrium type, they are classified into systems with no equilibria, with a line of equilibrium points, and with one

Circuit Theory and Applications
Mechanical Design

Optimization of fractional-order RLC filters

This paper introduces some generalized fundamentals for fractional-order RL β C α circuits as well as a gradient-based optimization technique in the frequency domain. One of the main advantages of the fractional-order design is that it increases the flexibility and degrees of freedom by means of the fractional parameters, which provide new fundamentals and can be used for better interpretation or best fit matching with experimental results. An analysis of the real and imaginary components, the magnitude and phase responses, and the sensitivity must be performed to obtain an optimal design

Circuit Theory and Applications
Software and Communications
Mechanical Design

Chaotic system modelling using a neural network with optimized structure

In this work, the Artificial Neural Networks (ANN) are used to model a chaotic system. A method based on the Non-dominated Sorting Genetic Algorithm II (NSGA-II) is used to determine the best parameters of a Multilayer Perceptron (MLP) artificial neural network. Using NSGA-II, the optimal connection weights between the input layer and the hidden layer are obtained. Using NSGA-II, the connection weights between the hidden layer and the output layer are also obtained. This ensures the necessary learning to the neural network. The optimized functions by NSGA-II are the number of neurons in the

Artificial Intelligence
Circuit Theory and Applications

Chaotic system modelling using a neural network with optimized structure

In this work, the Artificial Neural Networks (ANN) are used to model a chaotic system. A method based on the Non-dominated Sorting Genetic Algorithm II (NSGA-II) is used to determine the best parameters of a Multilayer Perceptron (MLP) artificial neural network. Using NSGA-II, the optimal connection weights between the input layer and the hidden layer are obtained. Using NSGA-II, the connection weights between the hidden layer and the output layer are also obtained. This ensures the necessary learning to the neural network. The optimized functions by NSGA-II are the number of neurons in the

Artificial Intelligence
Circuit Theory and Applications

FPGA-Based Memristor Emulator Circuit for Binary Convolutional Neural Networks

Binary convolutional neural networks (BCNN) have been proposed in the literature for resource-constrained IoTs nodes and mobile computing devices. Such computing platforms have strict constraints on the power budget, system performance, processing and memory capabilities. Nonetheless, the platforms are still required to efficiently perform classification and matching tasks needed in various applications. The memristor device has shown promising results when utilized for in-memory computing architectures, due to its ability to perform storage and computation using the same physical element

Artificial Intelligence
Circuit Theory and Applications
Software and Communications