A Novel Algebraic Technique for the Construction of Strong Substitution Box

Magnetic induction applications mostly rely on resonance for inducing maximum magnetic fields to system loads and hence for each resonant frequency dedicated circuits are required. Unfortunately, the frequency responses of such inductive systems manifest several peaks (frequency splitting) when their coupling coefficients are equal to or larger than critical coupling. Such frequency responses with several peaks are detrimental when the objective is to transfer maximum energy. Frequency splitting between inductive coils have been seen to date as detrimental to wireless power transfer and inductive communication systems. In this paper it is demonstrated that frequency splitting is a welcome phenomenon with advantage in the design of inductive filter banks and multi-frequency inductive systems. The centre frequencies of the filter banks result from split bands of inductive systems. This phenomenon is applied in conjunction with an innovative recursive algorithm to design inductive filter banks. The filters straddle both sides of the resonant frequency position and can be resolved individually.     

Output regulation of nonlinear systems using conditional servocompensators

This paper studies the output regulation of nonlinear systems using conditional servocompensators. Previous work introduced the conditional servocompensator, which acts as a traditional servocompensator in the neighborhood of a zero-error manifold while acting as a stable system otherwise, leading to improvement in the transient response while achieving zero steady-state regulation error. The conditional servocompensator tool was introduced for sliding-mode feedback controllers. This paper extends the technique to more general feedback controllers by using Lyapunov redesign and saturated high-gain feedback.     

An Improved Chaotic Cryptosystem for Image Encryption and Digital Watermarking

Wireless Personal Communications - In this article, enhanced chaotic range map is used for data hiding and multimedia security. By using complex properties of improved chaotic logistic map that...     

CuO as sintering additive to Sr0.4Ca0.6La4Ti5O17 ceramics

The effects of CuO addition on the sintering behavior and microwave dielectric properties of Sr_0.4Ca_0.6La₄Ti₅O₁₇ ceramics were investigated. CuO was selected as a liquid phase sintering aid to lower the sintering temperature of Sr_0.4Ca_0.6La₄Ti₅O₁₇ ceramics. With CuO addition, the sintering temperature of Sr_0.4Ca_0.6La₄Ti₅O₁₇ ceramics was effectively reduced from 1550 °C to 1475 °C. The crystalline phase exhibited no phase difference and no second phase was detected at all addition levels. The electric permittivity was not significantly affected by various amounts of CuO addition and ranged from 52 to 54. Small values (<+7 ppm/K) of the temperature coefficient of resonant frequency were obtained for Sr_0.4Ca_0.6La₄Ti₅O₁₇ ceramics. However, the unloaded quality factor Q _u was strongly dependent upon the CuO concentration. Q _u f _o ～ 10500 GHz was obtained for Sr_0.4Ca_0.6La₄Ti₅O₁₇ ceramics with 0.5 wt.% of CuO addition, sintered at 1475 °C.     

An extended observer-based robust nonlinear speed sensorless controller for a PMSM

This work focuses on the problem of observer-based robust speed sensorless control of a 3-phase permanent magnet synchronous motor (PMSM). Nonlinear design techniques are employed for designing robust speed controller and observer that are able to withstand the effects of modelling uncertainties and load variations. A new cascaded observer scheme is proposed comprising a continuous sliding mode observer (SMO) and an extended high-gain observer (EHGO). The proposed cascaded observer reduces chattering, exhibits reasonable insensitivity to modelling inaccuracies and is capable of withstanding errors due to the finite boundary layer of continuous SMO. For the robust speed control, an integral sliding mode controller is designed that yields fast and accurate speed tracking performance even in the presence of bounded uncertainties and external disturbances. The complete scheme has been evaluated using simulations and experiments.     

Cryptosystem techniques based on the improved Chebyshev map: an application in image encryption

Multimedia Tools and Applications - The use of nonlinear (chaotic) transformations in cryptography to create confusion during encryption process has become a common practice. In this paper, a pair...