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The main objective of this paper is to improve the identification efficiency of non-linear systems using the Kalman filter (KF), which is optimised with the Artificial Electric Field (AEF) algorithm. The conventional KF suffers from the proper tuning of its parameters, which leads to a divergence problem. This issue has been solved to a great extent by the meta-heuristic AEF algorithm assisted Kalman filter (AEF-KF). This paper proposes three steps for the identification of the systems while solving the problem as mentioned above. Firstly, it converts the identification model to a measurement problem. Next, the AEF algorithm optimises the KF parameters by considering the fitness function with the KF equations. The third step is to identify the model using conventional KF algorithm with the optimised KF parameters. To evaluate the performance of the proposed method, parameter estimation error, mean squared error (MSE), fitness (FIT) percentage, statistical information and percentage improvement are considered as the performance metrics. To validate the performance of the proposed method, five distinct non-linear models are identified with the Volterra model using KF and the AEF-KF techniques under various noisy input conditions. Besides, the practical applicability of the proposed approach is also tested on two non-linear benchmark systems using experimental data sets. The obtained simulation results confirm the efficacy and robustness of the proposed identification method in terms of the convergence speed, computational time and various performance metrics as compared to KF, Kalman smoother (KS) which is optimised using different state-of-the-art evolutionary algorithms and also other existing recently reported similar types of stochastic algorithms based approaches.

The effect of grain refiner on microstructural features, casting defects, formation of precipitates and eutectic Si particles, which influence the hardness and tensile properties of Al-Si alloys, is investigated in this study. The A-7Si alloy was prepared through melting and casting route with varying wt.% of Ti up to 0.2%. XRD, SEM and HRTEM analyses characterize the phases and aluminide (TiAl3 and Ti7Al5Si12) precipitates. The thermodynamic analysis, carried out by using FactSage software, confirms the presence of aluminides particle in the microstructure, which is formed at the liquid stage. The microstructure of as-cast Al-7Si alloy contains primary α-Al phase with dendritic morphology and eutectic phase having plate-like eutectic Si particle which is distributed at interdendritic regions. The morphology of primary α-Al grains is altered from dendrite network to fine equiaxed rosette type structure. Secondary dendrite arm spacing (SDAS) is reduced after adding grain refiner (Al-5Ti-1B) to the Al-7Si alloy. The eutectic Si is also refined to fine fibrous type particles. The shrinkage porosity and microcracks are also reduced after the addition of a grain refiner. The yield strength, ultimate tensile strength and elongation to fracture increase from 84, 117 MPa and 16% to 112 MPa, 148 MPa and 22%, respectively, after the addition of 0.1% Ti due to significant reduction in SDAS. Elongation decreases when the percentage of Ti increases more than 0.1%. The fracture mechanism of grain-refined alloy is changed from brittle to ductile fracture.

The present manuscript has proposed a capacitance-based model of dual material gate charge plasma-based vertically t-shaped Tunnel Field Effect Transistor (DMG V-tTFET) with spacer regions. The surface potential model, which modulates terminal capacitance and the drain current model is used to analyse the Poisson Equation (PE). For modelling the n-type channel, the inclusions are an enhancement-mode, accumulated charges, and ionized impurity charge carriers. The spacer region’s surface potential and channel region potential are inspected with modelling whose outcomes are authenticated by the simulations in the Silvaco TCAD software for various boundary conditions. The potential model is found by allocating the proposed device into ten distinct units and applying the 1-Dimensional (1-D) and 2-Dimensional (2-D) PE in their respective sections. To resolve the PEs for different sections, the parabolic approximation method is employed. The impact of geometrical variety, for instance, the spacer length and tunnelling width are analysed with dependence upon the electrical characteristics of DMG V-tTFET. The surface potential of greater than 0.75 V at a power supply voltage of 0.5 V is attributed to the establishment of an energy barrier in the channel with optimal device parameters.

The present study aims at development of nano-AlN reinforced aluminum metal matrix composite through stir casting method. For this commercially pure aluminum (CP-Al) and CP-Al + 2 wt% AlN nano-composite were casted at 760 °C by stir casting method. Both the alloy and the composite were subsequently characterized using optical microscopy and scanning electron microscopy. They were further tested for mechanical properties and dry sliding pin-on-disk wear studies were carried out at three different loads at room temperature at 200 rpm up to a sliding distance of 2 Km. The results indicate good particle dispersion into the matrix and massive grain refinement in the nano-composite. Accordingly, there is an improvement in UTS and 0.2% YS values by more than 100% by keeping ductility unaffected in the composite compared to the base alloy. Grain refinement and strengthening effect of nano-particles are the reasons for this improvement. Moreover, the wear study reflects considerable improvement in wear resistance in the composite at all loads. Suppression of adhesion (at all loads) and plowing abrasion (at 60 N load) are attributed to this improvement in wear resistance in the composite.

In this work, a novel design of ArcTFET based on Charge-Plasma and Gate-Stack (CP-GS-ArcTFET) is proposed for the first time. The precise detection of breast cancer biomarker (C-erbB-2) through serum should not be limited by HEMT devices but should be explored with other novel devices also. In this regard, investigation in above-mentioned device is carried out for the detection of C-erbB-2 protein. In CP-GS-ArcTFET, various central angles (θ) are considered for observing the electrical parameters e.g., drain current (I

An efficient analysis of time-modulated array (TMA) toward realizing less-attenuating radiation patterns with simultaneously suppressed sidelobe and sidebands is presented in this paper. In this framework, an optimal outer element-controlled time sequence is derived. The proposed time scheme, along with optimized array excitations, is profitably applied for the desired solution. TMAs are considered unconventional alternatives to the phased arrays. The desired array radiation features can be attained by periodically enabling and disabling the array elements through high-speed switches. Despite the advantages of architectural simplicity and real-time reconfigurability of periodic time sequences, time-domain antenna arrays inherently generate unavoidable sideband radiations (SRs). The undesired SRs obtained at multiple harmonics around the carrier frequency of the array resembles power loss in unintended directions. This paper aims to minimize the SRs as well as the sidelobe level (SLL) for an efficient analysis of time-modulated linear array (TMLA) with high-directive radiation patterns. The starting instants and the period of on-times are optimized to generate a unique shifted time scheme for the edge elements of the TMLA to reduce the sideband levels (SBLs). The array excitations and the uniform spacing between the elements are also optimized together with the shifted time scheme for the coveted solution. Other methods of suppressing SLLs and SBLs with shifted pulse schemes and sub-sectioned pulse schemes are also presented for a fair comparison. Modified versions of the particle swarm optimization algorithm (PSO) are applied for the desired solutions. The optimal results attained by wavelet mutation-based novel PSO is compared with the conventional PSO and the modified novel PSO-based results. The representative results are reported, and the superior performance abilities of the proposed method compared to other published studies are assessed.

An efficient compensation method is proposed for the reduction of mutual coupling among the elements of an antenna array using the optimum current amplitude excitation weights. The performance of an antenna array degrades heavily due to mutual coupling. The mutual coupling effect can neither be eliminated nor be ignored in the context of the antenna array design. Several analytical and numerical techniques have been proposed in the past few decades for the calculation and compensation of mutual coupling effect. Here, the mutual coupling is compensated by reducing the driving impedance of each identical array element in the array by adopting grey wolf optimization and moth flame optimization algorithms, respectively. The sum of the driving impedances of each element of the antenna array is reduced efficiently by adjusting the feed current amplitudes of all the individual array elements. Compared to the existing known methods, the proposed method is less complex, cost‐effective and easy to implement for commercial and industrial applications to achieve better performance.

This paper presents a time modulated far-field radiation pattern synthesis of a compact circular antenna array (CAA) by employing a stochastic optimization technique known as grey wolf optimization...

This article introduces an optimal design of finite impulse response-type Riesz fractional-order digital differentiator (FODD) of orders p = 0.3, 0.5, and 0.75. A very little study on Riesz-based differentiator has been reported so far. Moreover, none of the published Riesz FODD-based literature has studied the optimal design of Riesz FODD, which is explored in this article. In the reported literature, the Riesz FODD is realized by adopting conventional mathematical approaches, which are not efficient for the Riesz FODD-type design problem where the nature of the search landscape is multidimensional, multimodal, non-uniform, and nonlinear. To solve this problem, the design parameters of the proposed Riesz FODDs are estimated by using three independent metaheuristic optimization algorithms called salp swarm algorithm (SSA), gases Brownian motion optimization (GBMO), and gravitational search algorithm (GSA). In SSA, the adaptive variation of the iteration-dependent parameters helps the search agents not only to avoid the suboptimal solutions, but also ensures the faster convergence to reach the near-global optimal solution compared to GSA- and GBMO-based design approaches. The maximum phase error (MPE) and maximum absolute magnitude error (MAME) of the proposed SSA-based Riesz FODD are as low as 3.7119E−014 degree and − 9.6824 dB, respectively, for p = 0.3; 3.1523E−014 degree and − 15.6443 dB, respectively, for p = 0.5; and 3.5780E−014 degree and − 18.7525 dB, respectively, for p = 0.75. In terms of MPE and MAME, the proposed SSA-based Riesz FODD significantly outperforms the GSA- and GBMO-based Riesz FODD designs. The proposed SSA-based Riesz FODD of order p = 0.5 is also implemented on the TMS320C6713 digital signal processor, and its precise zero-phase performance is tested on real electrocardiogram (ECG) signal. Moreover, the proposed Riesz FODD is utilized in the ECG QRS complex identification system to demonstrate its real-time application.

This paper proposes an efficient global gravitational search (GGS) algorithm-assisted Kalman filter (KF) design, called a GGS-KF technique, for accurate estimation of the Volterra-type nonlinear systems. KF is a well-known estimation technique for the dynamic states of the system. The best estimate is achieved if the system dynamics and noise statistical model parameters are available at the beginning. However, to estimate the real-time problems, these parameters are unstipulated or partly known. Due to this limitation, the performance of the KF degrades or sometimes diverges. In this work, two steps have been proposed for unknown system identification while overcoming the difficulty encountered in KF. The first step is to optimise the parameters of the KF using the GGS algorithm by considering a properly balanced fitness function. The second step is to estimate the unknown coefficients of the system by using the basic KF method with the optimally tuned KF parameters obtained from the first step. The proposed GGS-KF technique is tested on five different Volterra systems with various levels of noisy (10 dB, 15 dB and 20 dB) and noise-free input conditions. The simulation results confirm that the GGS-KF-based identification approach results in the most accurate estimations compared to the conventional KF and other reported techniques in terms of parameter estimation error, mean-squared error (MSE), fitness percentage (FIT%), mean-squared deviation (MSD), and cumulative density function (CDF). To validate the practical applicability of the proposed technique, two benchmark systems have also been identified based on the original data sets.

This paper presents an efficient approach for the design of a non-uniform single ring circular antenna array (CAA) for the synthesis of the optimal far-field radiation pattern. A recently proposed meta-heuristic-based optimization technique known as ant lion optimization (ALO) is applied in this paper to determine the optimum set of current amplitude excitation weights and the inter-element distance among the array elements to reduce the side lobe level (SLL) and 3-dB beam width considering the mutual coupling effect. The results achieved by employing the ALO algorithm are compared with the uniform radiation pattern and with those of the recently reported literature containing equal sets of elements to prove the superiority of ALO algorithm. Three different design examples of 8, 10, and 12 elements CAA are presented, and their performances are compared to illustrate the capability of the ALO algorithm-based approach over those of the recently reported literature.

This paper presents an efficient method to improve the far-field radiation pattern of concentric circular antenna array (CCAA) design using two stochastic optimization algorithms known as social sp...

In this paper, high port isolation in dual feed orthogonally polarized square patch antenna array is achieved by the use of Defected Ground Structure (DGS). A simple rectangular-headed cross DGS is...

In this article, the performance of n-type junctionless (JL) double-gate (DG) MOSFET-based biosensors with and without gate stack (GS) has been studied. Here, the dielectric modulation (DM) method is applied to detect biomolecules in the cavity. The sensitivity of n-type JL-DM-DG-MOSFET and n-type JL-DM-GSDG-MOSFET-based biosensors have also been evaluated. The sensitivity (ΔVth) improved in JL-DM-GSDG MOSFET/JL-DM-DG-MOSFET-based biosensors for neutral/charged biomolecules is 116.66%/66.66% and 1165.78%/978.94%, respectively, compared with the previously reported results. The electrical detection of biomolecules is validated using the ATLAS device simulator. The noise and analog/RF parameters are compared between both biosensors. A lower threshold voltage is observed in the GSDG-MOSFET-based biosensor. The Ion/Ioff ratio is higher for DG-MOSFET-based biosensors. The proposed GSDG-MOSFET-based biosensor demonstrates higher sensitivity than the DG-MOSFET-based biosensor. The GSDG-MOSFET-based biosensor is suitable for low-power, high-speed, and high sensitivity applications.

In this paper, conventional charge-plasma nanowire tunnel field-effect transistor (CP-NWTFET) has been applied by gate stacking and SiGe sourced to design the proposed Si0.55Ge0.45 sourced nanowire tunnel field-effect transistor based on charge plasma and gate stack (SiGe-GS-CP-NWTFET) to enhance electrical characteristics. Comparison of drain current (Id), transconductance (gm), second-order transconductance (gm2), third-order transconductance (gm3), and transconductance generation factor are analysed between conventional CP-NWTFET and SiGe-GS-CP-NWTFET. The results demonstrate that the proposed SiGe-GS-CP-NWTFET device possesses a larger drive current, transconductance, and transconductance factor those of the conventional device. Further, the impact of temperature on various parameters such as subthreshold slope (SS), threshold voltage (Vth), Ion, Ioff, and Ion/Ioff ratio is analysed for the proposed SiGe-GS-CP-NWTFET device. With an increase in temperature, both ON-current and OFF-current upsurge which results in a decrease in the current ratio. A lower subthreshold slope is observed for lower temperature, whereas a lower threshold voltage is observed for higher temperature. The parameters, like the electric field, potential, and energy band diagram which help in understanding the physics of the device, are also analysed for various temperatures. The impact of mole fraction(x) of Ge in SiGe on SS, Vth, Ion, Ioff, and Ion/Ioff ratio is also analysed for the proposed device. Ion, Ioff increase with mole fraction, whereas Vth decreases with temperature. The current ratio and SS are found to be better for the mole fraction of x = 0.45. The improved performance compared to the conventional CP-NWTFET is attributed to the superiority of the proposed SiGe-GS-CP-NWTFET device.

This work is concerned with the methodology for improvement of the radiation pattern performance and eliminating the effect of unwanted interference of symmetric time modulated linear antenna array...