This study deals with the problem of controlling class of uncertain non-linear systems in the presence of external disturbances. To achieve this goal, a robust fuzzy sliding mode (RFSM) controller is introduced. First known dynamics of the system are eliminated through feedback linearisation and then fuzzy sliding mode controller is designed using Takagi–Sugeno (TS) method, based on the Lyapunov method which is capable of handling uncertainties. There is no sign of the undesired chattering phenomenon in the proposed method. The globally asymptotic stability of the closed-loop system is mathematically proved. In order to evaluate the performance of the proposed controller, the results are compared with those obtained by optimal H _∞ adaptive proportional integral derivative controller and an optimal Type-2 fuzzy proportional integral derivative, which are the latest researches in the problem in hand. Simulation results show the effectiveness of the RFSM controller.

Although today water is becoming more and more precious, its major waste is caused by transportation. The authorities in charge of the management of water pipes indicate double-digit percentage of waste, sometimes it even exceeds 50% the amount of water mostly lost by inefficiency of distribution waterworks. In this study, the authors present an alternative method of spectral analysis, used for detecting leaks in water pipes, with respect to classical spectral methods as direct Fourier transform/fast Fourier transform. They have used decimated Padè approximant (DPA), where the input time signal points or auto-correlation functions are given via measurements or computations, and the task is to reconstruct the unknown components as the harmonic variables in terms of the fundamental complex frequencies and amplitudes. They have also introduced decimated linear predictor technique as direct consequence of the DPA, since they differ only in one step, namely the calculation of the amplitudes.

Many ultrasonic sensors intended for non-destructive testing include a plastic or metal element, known as buffer rod, between the ultrasonic transducer and the material under analysis. Buffer rods are often terminated in the form of a conical tip for ultrasonic inspection of liquid-like substances. The conical tip is carefully shaped in a 45° angle to favour the in phase reception of all the components of the ultrasonic wave reflected at the buffer tip, obtaining thus a maximum amplitude measurement signal. The effect of the buffer rod cone angle on measurement signals is studied in this work. A straightforward approximate formula for the effect of the error angle on measurement signal amplitude is used. Simulations are performed using a two-dimensional finite differences tool. Measurements are conducted with the same operating conditions and buffer rod materials and dimensions as those defined for both approximate formula evaluation and simulations. Thus, a comparison of the approximate formula, simulation and measurement results are established. Furthermore, the significance of some parameters such as ultrasonic transducer operating frequency and diameter, and buffer rod material are also analysed. The obtained results show that significant loss of the measurement signal amplitude is found only for cone error angles beyond the range of usual machining errors.

This study presents the synthesis and implementation of non-bridge quasi-balanced circuit designed to measure the dielectric loss factor. Synthesis is performed on the basis of the well-known bridge circuit. The equations of detected signal have been derived and their processing equations have been developed using a general model of a quasi-balanced circuit. Then, a structural diagram describing the processing of signals in the two states of quasi-equilibrium has been derived. An example of a virtual implementation of the derived circuit has been presented.

This study presents an enriched reliability index approach for reliability-based design optimisation of electromagnetic devices in the presence of variability in design variables. To substantially improve computational efficiency, two new optimisation strategies consisting of a constraint indicator condition and a successive optimum search technique are incorporated into the existing method based on the reliability index approach. The constraint indicator decides whether reliability analysis is needed for each intermediate design during the reliability-based optimisation process. Employing the successive optimum search technique, a deterministic optimum is first sought from an initial design and then a probabilistic optimum is obtained by launching at the deterministic optimum. The proposed method is tested with a coil design problem for a superconducting magnetic energy storage system, and is thoroughly investigated by comparing the results with the conventional method based on the reliability index approach and the Monte Carlo simulation in terms of computational efficiency and accuracy. Finally, the results show that the method leads to a significantly decreasing computational cost.

Automated karyotyping for chromosome classification is an essential task in cytogenetics for diagnosis of genetic disorders and has therefore been an important pattern recognition problem. The existing learning approaches generally discard the previously acquired knowledge and often require retraining, leading to space and time complexities. Incremental learning methods have gained popularity in the current learning scenarios to deal with these issues. This study proposes a novel approach of incremental learning for chromosomes classification for automated karyotyping of metaphase chromosomes. It addresses the issue of catastrophic forgetting with the generation of new class and performs knowledge amassing to classify the chromosomes in Denver groups (A–G). The adaptive nature of the proposed method contributes to its sustained accuracy even for dynamically changing data. An average classification accuracy of 97% is achieved with experimentation on 1800 chromosomes from a publicly available database.