Currently, the uniform linear array (ULA) is the most commonly used antenna system for different wireless systems like commercial cellular systems. In this study, a ULA adaptive antenna that uses a novel numerical sto...
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Currently, the uniform linear array (ULA) is the most commonly used antenna system for different wireless systems like commercial cellular systems. In this study, a ULA adaptive antenna that uses a novel numerical stochastic optimisationalgorithm inspired from colonising weeds, designated as invasive weed optimisation (IWO), is introduced. Weeds are shown to be very robust and adaptive to changes in the environment. Thus, capturing their properties leads to a powerful optimisationalgorithm. This optimisationalgorithm is used for adaptive beamforming;the obtained results are compared with the results obtained from two other optimisationalgorithms, that is, the least mean square and genetic algorithms. The reported results show that the IWO is very robust and effective in locating the optimal solution with higher precision and a lower cost function when compared with the other two algorithms. Other advantages of the IWO algorithm is its simplicity and fast convergence, which makes it a practical algorithm for adaptive beamforming.
This paper deals with the problem of designing the (PID mu)-D-lambda-type controllers for minimum-phase fractional systems of rational order. In such systems, the powers of the Laplace variable, s, are limited to rati...
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This paper deals with the problem of designing the (PID mu)-D-lambda-type controllers for minimum-phase fractional systems of rational order. In such systems, the powers of the Laplace variable, s, are limited to rational numbers. Unlike many existing methods that use numerical optimisation algorithms, the proposed method is based on an analytic approach and avoids complicated numerical calculations. The method presented in this paper is based on the asymptotic behaviour of fractional algebraic equations and applies a delicate property of the root loci of the systems under consideration. In many cases, the resulted controller is conveniently in the form of P, I-lambda, PD mu or (PID mu)-D-lambda. Four design examples are explained and the results are compared with existing fractional-order PIDs. These results confirm the usefulness of the proposed method.
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