Scanning the Issue

The current issue of the IETE Journal of Research (Vol 69, No 2, February 2023) contains 50 articles. These articles present ongoing research and developments taking place in the broad areas of computer science, biomedical engineering, electromagnetics, electrical and electronics engineering, microelectronics and power systems.

The paper titled “A Secured Zobrist Hash Symmetric Sentinel List Based Malicious Attack Detection in VANET” proposes a list-based malicious attack detection scheme based on Zobrist Hash, called Secured Zobrist Hash Symmetric Attack Detection (SZ-HSAD), to secure VANET to a greater extent. The proposed SZ-HASD integrates symmetric cryptography-based initialization for an efficient and robust trust management scheme. A system initialization is a crucial component of trust establishment and secure communications between vehicles. The initialization of the system incorporates Zobrist Hash Optimal Distance Registration. Based on the identity, the trusted authority (TA) evaluates the keys for both the Roadside Unit (RSU) and vehicles. For timely and early attack detection in VANET, a list-based malicious attack detection using symmetric and sentinel nodes is designed.

In the paper titled “A New Approach to Vision-based Fire and its Intensity Computation Using Spatio-Temporal Features,” a novel framework is proposed that utilises angular and regional area information of the fire flame to predict the presence of a fire flame in a sequence of video frames. The proposed system specifically addresses false fire detection in video. The results obtained from multiple datasets of fire videos indicate that the extracted features derived from the proposed framework effectively discriminate between fire and non-fire objects. These characteristics can also be utilised to estimate the size and direction of a flame.

The paper “Framework for Identification of Critical Factors for Open-Source Software Adoption Decision in Mission-Critical IT Infrastructure Services” looks into and analyses OSS adoption factors for “critical IT infrastructure” by doing a thorough review of the relevant literature. Also talked about is a framework that can help the critical IT industry have more faith in OSS. The proposed framework is based on the logic of the Technology, Organization, and Environment (TOE) framework and suggests factors that can be seen by carefully looking at the studies that are already out there.

The idea of an iterative learning controller (ILC) is presented in the paper “Real-Time Implementation of Iterative Learning Control for an Electro-Hydraulic Servo System.” An intelligent and memory-based learning control method is described that tries to mimic the way humans think. The proposed ILC adds a learning gain, a learning filter, and a robustness filter to improve the performance and stability of tracking in finite time. The focus of the study is on how to make an ILC that controls the servo spool valve of an EHSS, which in turn controls how far a hydraulic cylinder moves. Simulations and experiments have shown that the ILC performs better than traditional PID controllers when it comes to important parameters like overshoot and settling time.

The paper titled “FDTD Based Simulation of Light Extraction in OLED Using Triangular Band Structure” employs Finite Difference Time Domain (FDTD) mathematical modelling to measure the Purcell factor and analyse the light extraction efficiency in the triangular band structure of OLED displays. Due to the rectangular shape of the FDTD solver region, it is necessary to include multiple unit cells in the solver region in order to account for the triangular band structure. By optimizing the angular distribution of light through the substrate using a triangular band structure, it is possible to increase the far-field intensity of OLEDs. Therefore, it can be utilized extensively in ultra compact optical devices.

The authors of the paper titled “Hybrid Elliptic Curve Cryptographic Approach for Data Privacy and Authentication in Secured Map Reduce Layer (SMR) for Optimized CPU Utilization” propose Secured Map Reduce Layer (SMR) in the big data structure for optimizing CPU utilization using Hybrid PSO/CS (Particle Swarm Optimization/Cuckoo Search) and Elliptic Curve Cryptographic approaches. Using either particle swarm optimization or cuckoo search algorithm, the proposed method selects the private key for authentication and provides encryption and decryption via Key-Value Pair (KVP) of Elliptic Curve Cryptographic.

Privacy Protection, Data Sharing, and Management are discussed in the paper titled “A Secured Healthcare Management and Service Retrieval for Society Over Apache Spark Hadoop Environment.” In both stages of data retrieval and management, data requestors and data owners who wish to store data in the HDFS and share it with others must first be authenticated. Secondly, a new model is presented to assist the requestor in selecting trustworthy and comparable partners who wish to access the health data stored in HDFS clusters, and to provide them with an accurate list of partners. Thirdly, HDFS-stored patient medical data is clustered, and their health status (diseases or other serious threats) is determined using a Deep learning algorithm in a Spark environment. To prevent patients from contracting serious diseases, a final report is generated and distributed to stakeholders. The presented experiments demonstrate the efficacy of the proposed method in terms of accuracy, precision, recall, and f-measure.

In the paper titled “Atom Search Optimized FOPI Controller of the DC–DC SEPIC Model with Matignon's Theorem Stability Analysis,” the design and implementation of an optimized fractional-order proportional-integral (FOPI) controller for a DC–DC single-ended primary inductance converter (SEPIC) is considered to fulfill the application of power factor correction and voltage regulation in addition to enhanced robustness, efficiency, and performance characteristics of the converter. A technique called Atom Search Optimization is proposed for optimizing the controller parameters in the outer voltage and inner current control loops of the DC–DC SEPIC model. MATLAB–Simulink is used to develop the model, and simulation analysis is performed at rated load, setpoint tracking, source voltage, and load variation.

The paper titled “Vision-based Hand Gesture Recognition for Indian Sign Language Using Convolution Neural Network” proposes a system that eliminates the communication barrier between the Hard of hearing (HoH) community and those who are unfamiliar with their sign language. Using the Microsoft Kinect sensor, an algorithm to detect and segment the hand region from a depth image is proposed. The algorithm is effective in a cluttered environment, such as a skin-toned background and a hand covering the face. Convolution Neural Networks (CNN) are utilized to construct automatically features from Indian Sign Language (ISL) signs. These characteristics are rotation and scaling invariant. The proposed system accurately recognizes gestures up to 99.3%.

The paper titled “Mining Frequent Patterns Partially Devoid of Dissociation with Automated MMS Specification Strategy” introduces Auto MMS-FPM, an automated MMS specification strategy for mining frequent patterns partially devoid of dissociation. To enhance the mining process, the proposed method takes into account not only support, but also influence (inf), dissociation (d), and length importance factor (ρ). Influence refers to the inter-item relationship and is derived from the concept of degree centrality of the respective item network. MIS for the items are automatically calculated using MB S and RI F factors, the first of which relates to item support and the second to item influence. Experimental results on both synthetic and real data sets demonstrate that the proposed algorithm outperforms existing methods in terms of number of generated item sets, run time, memory usages, dissociation, and scalability.

The authors of the paper titled “ADVISOR-Based Performance Analysis of a Hybrid Electric Vehicle and Comparison with a Conventional Vehicle” present a comparative performance analysis of a small HEV in pure ICE, series HEV (SHEV), and parallel HEV (PHEV) configurations. The simulation software Advanced Vehicle Simulator (ADVISOR) is utilised on the Matlab/Simulink platform. In addition to the acceleration performance and gradeability tests, vehicle emissions are examined to determine the results.

In the article titled “A Sturdy Nonlinear Hyperspectral Unmixing,” a robust nonnegative matrix factorization (S-NMF) is presented along with an integrated fast dissociable non-local Euclidean median and iterative block coordinate descent algorithm (IFD-NLEM-IBCDA). FD-NLEM is used to remove mixed noise from acquired HSI without lowering the original quality, and IB-CDA is then used to unmix the HSI by solving the S-NMF minimization problem. Also provided is a solution for the hyperparameter used in the S-NMF minimization step of the IB-CDA. Numerous simulation results on both real and artificial HSI show that anticipated unmixing under mixed noise conditions outperforms traditional unmixing algorithms.

The authors of the paper titled “Towards Neuro-Fuzzy Compensated PID Control of Lower Extremity Exoskeleton System for Passive Gait Rehabilitation” designed a neuro-fuzzy compensated PID control for passive gait rehabilitation using a lower extremity exoskeleton system. A 6-DOFs exoskeleton prototype is developed to assist children aged 8 to 10 years old. In this study, the experimental runs are performed using a dummy whose body characteristics match those of a healthy 10-year-old child. To compute the desired joint angles in the sagittal plane for a healthy gait trajectory, a Kinect-LabVIEW setup is utilised. Utilizing the Euler–Lagrange method, the dynamic analysis of the exoskeleton system is formulated.

The paper titled “A Comparative Analysis of Data-Driven Based Optimization Models for Energy-Efficient Buildings” compares data-driven based optimization models that simultaneously maximise the comfort index and reduce energy consumption. To maintain indoor thermal comfort, heating-cooling systems are utilised, with energy consumption proportional to the outdoor temperature and indoor temperature differential. Using optimization techniques such as Genetic Algorithm (GA), BAT, Neural Network Algorithm (NNA), Particle Swarm Optimization (PSO), and Artificial Bee Colony (ABC), the environmental temperature parameter is optimised (ABC). The primary objective of the optimization is to reduce the difference or error between the user-specified temperature and the surrounding temperature. The BAT model has demonstrated its effectiveness in achieving a high comfort index with minimal energy consumption when compared to other models considered.

In the paper titled “Gain Augmentation of a Triple Notched Ultra wideband Antenna using Compact Uniplanar Frequency Selective Surface for Ground Penetrating Radar,” the authors present a simple structured, compact ultra-wideband (UWB) circular disc monopole antenna of dimensions 35 × 30 × 0.8 mm3 that offers a wide bandwidth from 2.64 to 9.36 GHz with sharp triple notch bands at 3.28–3.84, 5.08-5.44, and 5.62-6.06 GHz. The antenna is incorporated into a single-layer UWB frequency selective surface (FSS) with unit cell dimensions of 0.1136λ_L × 0.1136λ_L, where λ_L represents the UWB's lower band-edge. By embedding a split-ring slot on a circular patch and implanting two circular split-ring resonator pairs at the rear of the feed, sharp triple notches are employed. The addition of the FSS layer has no effect on the antenna impedance band and significantly improves the antenna gain by 2–4 dBi in the passband, with a maximum gain of 8 dBi at 8.5 GHz. The proposed antenna's utility in ground penetrating radar is guaranteed by its adequate VSWR profile, linear transfer function response, and consistent group delay response in pass band.

The paper “A Novel Weighted Superposition Attraction Algorithm-based Optimization Approach for State of Charge and Power Management of an Islanded System with Battery and Super Capacitor-based Hybrid Energy Storage System” proposes a Hybrid Energy Storage System (HESS) employing a Battery and a Super Capacitor (SC). A SC reduces the strain on the battery and functions as a buffer against power fluctuations. The system is designed using the MATLAB/Simulink domain, and the simulation output demonstrates that the HESS has a more effective dynamic response than an ESS alone. Included is a PID controller that operates the parameters so that the system can provide rapid feedback. The disadvantage of the PID controller, however, is that it cannot respond to nonlinearity in a system. Hence, a robust Weighted Superposition Attraction Algorithm (WSAA) is implemented to dynamically tune the PID controller parameters for optimal operation.

The authors of the paper titled “Parametric Tracking Across Multiple Cameras with Spatial Estimation” describe a method for tracking a target based on the combination of parameters between colour blobs. In addition to tracking targets based on parameters between colour regions, the blob parameters can also be used to estimate the target's spatial location relative to the location of the cameras. By segmenting the overall target into multiple colour regions, the blobs are obtained. Using the EM technique, the colour regions are segmented. After segmentation into distinct regions on distinct colour layers, parameters between colour regions of interest can be generated. The colour regions of interest in this instance are the top and bottom colour regions. The vector magnitude, vector angle, and the value difference between colour regions are the parameters of interest between colour regions. These parameters are used to track the desired target across an array of cameras, which in this case consists of three cameras. The results of tracking targets with three cameras indicate that parameters between colour regions can be used to track targets across cameras.

The paper titled “Performance Evaluation of Voltage Ripple-Based Passive Islanding Detection Method for a Single-Phase Utility-Connected Microgrid System” focuses on the passive islanding detection method (IDM) that is simple to implement, cost-effective, and proficient. The proposed method assists in eradicating the drawback of passive conventional IDM. Low impedance grid always induced small deviation of inverter output in grid-connected mode, but when the grid is disconnected (i.e., in islanding condition), this stability effect of the grid is absent, which the proposed method exploits for islanding detection. In addition, passive IDMs based on voltage ripple are evaluated and tested under various operating conditions.

In the paper entitled “A Bus Clamping PWM-Based Improved Control of Grid Tied PV Inverter with LCL Filter Under Varying Grid Frequency Condition” the author presents a modified Synchronous Reference Frame Phase locked loop (MSRFPLL) for better synchronization of the output of the inverter with the grid. The proposed PLL can track the changes in the grid frequency in a faster way as compared to the conventional synchronous reference frame PLL (SRF-PLL).

The paper entitled “Mental Stress Assessment Using PPG Signal a Deep Neural Network Approach” presents studies on pulse rate variability (PRV) of 15 subjects during 5 cognitive states (relaxation, deep breathing, and during three mental tasks involving three levels of mental stress) that were examined using photoplethysmography (PPG). The result of this study indicates that 18 features (9-time domain and 9 frequency domain) are statistically significant at p < 0.05 as per the Friedman test in 5 cognitive states. The machine-learning algorithm based upon a multi-layer perceptron (MLP) was able to classify with an overall accuracy of 85.1 ± 1.1%. Classification accuracy further improved by using deep neural networks (DNN) to 91 ± 1.1%.

In the paper entitled “Distributed SM MPPT Controller for Solar PV System Under Non-Uniform Atmospheric Conditions” the authors present a diverse distributed maximum power point tracking (MPPT) method based on Cuk converter for solar photovoltaic system. The proposed MPPT method offers fast dynamic performance with absolute robustness by the concept of sliding mode control law to control the Cuk converter. It is shown that the proposed configuration improves the dynamic response and reduces the ripple to considerable amount, resulting in their operation closer to maximum power point.

The paper “An Approach for Diagnostically Lossless Coding of Volumetric Medical Data Based on Wavelet and Just-Noticeable-Distortion Model” looks at a method for visually/diagnostically lossless coding in the wavelet domain to effectively compress three-dimensional medical image data. The quality of the reconstructed data is guaranteed by the quantization module for wavelets that is based on Just Noticeable Distortion (JND). This method has been improved by adding the Volume of Interest (VOI)-based technique, which lets the quality of the diagnostically significant VOI region be kept.

In the paper “A Miniaturized Design of Dual-band Antenna for Bidirectional Brain Machine Interface Applications,” the authors describe the design of a new miniaturised printed monopole antenna for ultra-wideband (UWB) bidirectional brain machine interface (Bi-BMI) applications, based on defected feed line and parasitic structures. The proposed antenna structure is made up of a rectangular radiating patch and two inverted L-shaped slots between the patch and the feed line. This structure has a meander line parasitic structure that gives it a resonance frequency with a narrow bandwidth of almost 2.4 GHz and a running fractional bandwidth of more than 100% (3.19–10.63 GHz). It is reported that the proposed antenna has good radiation characteristics, a very low SAR, high fidelity, and almost omnidirectional radiation patterns across the whole band.

The paper entitled “A New Hybrid Arrangement of Iterative Learning Control Strategy for Ball and Beam System” deals with the control of the ball position on a beam using a new hybrid arrangement of Iterative Learning Control (ILC). If the process to be controlled is an under-actuated, unstable, nonlinear, and double integrating one, the conventional controllers are not able to control the system adequately. To overcome this problem, the ILC strategy is coupled in series with the conventional control scheme, thereby stabilizing the process with better convergence. The proposed Hybrid LIC (HILC) strategy is embedded in the existing control loop. A real-time implementation of the proposed control technique is carried out and its performances are reported.

In the paper “Design and Development of Banana Leaves-based Double-layer Microwave Absorber,” the authors talk about a double-layer microwave absorber made from banana leaves that could be used instead of traditional MAM. Authors used an OCP method and a vector network analyzer to measure the dielectric relaxation parameters of dry banana leaves in powder form and composites of dry banana leaves and charcoal powder in the frequency range of 1–16 GHz. In the frequency range of 1–20 GHz, the return loss of two single-layers and a double-layer with thicknesses of 4 and 8.02 mm is also studied. The results show that the double-layer absorber is much better than its single-layer counterparts in terms of both its electromagnetic properties and its ability to absorb energy.

In the paper “ZnO and Bi-metallic (Ag–Au) Layers Based Surface Plasmon Resonance (SPR) Biosensor with BaTiO3 and Graphene for Biosensing Applications,” the authors describe a new design for a surface plasmon resonance (SPR) biosensor made of Zinc Oxide (ZnO) and bi-metallic (Ag–Au) layers with barium titanate (BaTiO3) and graphene. The proposed structure is made up of an SF10 glass prism, ZnO, Ag, Au, BaTiO3, and graphene as a top layer for biomolecules adsorption. Here, the performance of this structure is studied and analysed for sensitivity, accuracy of detection, and quality parameter for the shift in refractive index (RI) from 1.33 (sensing medium) to 1.45. The results show that adding bimetallic (Ag–Au) layers along with BaTiO3 improves the sensitivity of the proposed structure to 14.85% for the same RI range compared to the reported MoS2-graphene-based SPR sensor. At λ = 632.8 nm, maximum sensitivity obtained is 116.67 degree/RIU while the accuracy of detection and the quality parameter obtained are as 4.54 and 37.87 RIU−1, respectively. The high-performance parameters of the design make this structure suitable for biosensing applications.

In the paper “A Comparative Survey of Convex Combination of Adaptive Filters,” the authors evaluate the convex combination of adaptive filters, which are mostly based on the least mean square (LMS) algorithm, the affine projection (AP) algorithm, and the recursive least mean square (RLS) algorithm. Extensive performance evaluations are also given to show what the pros and cons of each approach are. In particular, simulation is done in fixed point, which makes it possible to make advanced prototypes quickly. Reports say that this part could be useful for the signal processing engineering communities.

The paper “Automated Delimitation and Classification of Autistic Disorder Using EEG Signal” looks into how children with Autism Spectrum Disorder (ASD) respond to their senses. The EEG signal is used to find the non-linear features of this ASD. There are 73 EEG signals from different patients, of which 41 are from people with autism spectrum disorder (ASD) and 32 are from people with normal brain activity. Then, these signals are preprocessed and filtered with a low-pass filter, and Independent Component Analysis (ICA) is used to separate them into additive subcomponents. Important features are extracted, which can then be looked into further to find event-related potential and non-biological artifacts. Then, the Support Vector Machine (SVM), which has an accuracy of 90.41%, sorts these features into groups. So, the right sensory profiles can be made, which could help with early diagnosis and treatment of patients.

In the paper entitled “A Wideband High-Power Ridge Gap Waveguide Power Divider for High-Power Division Sub Systems Applications” the authors present a wideband high-power ridge gap waveguide (RGW) T junction power divider within the frequency band from 10 to 13.5 GHz. In this configuration, an excitation transition, from coaxial cable to the ridge gap waveguide, is introduced. The ridge gap waveguide power divider is fabricated using aluminum sheets to gain the advantage of low cost. The power divider has a wider bandwidth (30%) compared with the recent most successful RGW power dividers reported along with high handling power capability (more than 20 K Watts). The power divider design was validated using circuit and 3D full wave electromagnetic simulations and confirmed using experimental measurements with good agreement between simulated and measured results.

The paper entitled “Finite Element Analysis of Graphene Oxide Hinge Structure-based RF NEM Switch” presents design and simulation of hinge structure based Graphene oxide (GO) NEM switch. The Finite Element Modeling (FEM) of the NEM switch for different design parameters is performed in COMSOL Multiphysics. Moreover, the radiofrequency (RF) performance of the switch structure with minimum pull-in voltage has also been investigated. The results state that pull-in voltage and von Mises stress exhibit a negative correlation with beam length and positive correlation with beam thickness and air gap. Furthermore, a long and thin suspended beam requires low pull-in voltage and undergoes less von Mises stress. The von Mises stress exhibits a strong effect at beam edges, perforation corners, and beam-top electrode interface due to edge termination effect. The present work facilitates optimization of design parameters of a NEM switch that requires low pull-in voltage, undergoes less von Mises stress, and exhibits good RF performance.

In the paper “An Efficient Approach to Schedule Generating Units of Combined Heat and Power (CHP) Generating System,” the author describes two modes of CHP units, extraction and back-pressure, which offer more flexibility than the other mode. In the UC problem, the added value of CHP units’ different ways of running is still in its early stages. The CHP UC problem is then solved by using the optimization method. The binary particle swarm optimization is used to update the status of the unit, and the list method is used to find the best priority for the generation schedule. The economic and profit models of the CHP-UC problem have been solved with this method. One test system is made up of ten regular thermal units, one CHP unit, and one heat-only unit. The results of economic and profit models show that the CHP unit is important in different ways.

The paper entitled “Feature Selection for Simple Color Histogram Filter based on Retinal Fundus Images for Diabetic Retinopathy Recognition” presents study on the diagnosis for the Diabetic Retinopathy from the retinal fundus images by applying machine learning algorithms. The proposed work implements normalization, parameter tuning, and optimal feature selection method to improve the classification accuracy offered by selected algorithms like decision tree algorithm and K-nearest neighborhood classifiers. The highest accuracy of 81.99%, Weighted Average of Receiver Operating Characteristics (ROC) 0.907 are obtained by k-Nearest Neighbor (KNN) classifier due to its best performance.

The authors of the paper titled “Computer-Aided Detection and Diagnosis of Thyroid Nodules Using Machine and Deep Learning Classification Algorithms” propose a computer-assisted method for detecting and segmenting tumour regions in ultrasound thyroid images using machine and deep learning classification algorithms. The proposed tumour detection method uses Kirsch's edge detector to enhance the edge region pixels in the thyroid image before applying Dual Tree Contourlet Transform (DTCT) to obtain coefficients from the enhanced image. The transformed thyroid image is then used to compute features, which are then trained and classified using the Co-Active Adaptive Neuro Expert System (CANFES) classifier. On the abnormal thyroid image, the morphological segmentation method is then applied to segment the tumour regions. The Convolutional Neural Network (CNN) algorithm is then used to classify the segmented tumour regions as mild, moderate, or severe.

The article titled “Pressure Control of High Pressure Tubing Based on Fluid Mechanics” examines the issue of constant pressure control for high pressure tubing. Timing of check valve opening and cam angular velocity are the primary determinants of pressure change in a high-pressure oil pipeline. The flow-pressure model and pressure-cam angular velocity model are established, respectively, using the theory of fluid mechanics, ordinary differential equation, and Fourier series. In addition, this model is extended to include multiple nozzles. These three models accurately represent the functional relationship between the fuel flow rate, tube pressure, and cam angular velocity. According to established models, the high-pressure oil pipe's pressure can be precisely controlled by adjusting a few parameters. A simulation example is provided to demonstrate the efficacy of the proposed method.

In the paper entitled “Design of a Compact Dual-Band Antenna for ON-/ OFF Body Communication” the authors present a compact, dual-band, patch antenna structure for body-centric relay node communication. The antenna is designed to operate at Industrial, Scientific, and Medical (ISM) bands at 2.45 GHz for receiving data from intra-body sensor nodes and 5.0 GHz for transmitting signal to external monitoring device. The antenna is designed using coplanar waveguide feed and etching two open-end slots on radiating patch. Overall antenna dimensions are 15 mm × 28 mm × 1.57 mm. Effective dielectric constant for the multiple dielectric layers, due to its heterogeneous tissue structure, have been calculated. Antenna performance is measured both in free space and on tissue model.

The paper entitled “Design and Simulation of Reliable Low Power CMOS Logic Gates” presents a circuit-level reliable low leakage design methodology for integrated circuits (ICs). Low leakage circuit design is the most challenging research area for very large-scale integration (VLSI) circuit designers due to the increased demand of battery-operated portable systems. Leakage power is increasing continuously with each new technology node generation in deep sub-micron (DSM) regime. The various logic circuits are simulated and compared with the available leakage minimization techniques at 22 nm technology node using predictive technology model (PTM) bulk CMOS BSIM4 on HSPICE tool. Proposed approach reduces leakage power by ≈ 81% in XOR2 and XNOR2 gates as compared to conventional CMOS gates. Reliability of the nanoscale circuits is affected by several device parameters. Process, voltage, and temperature (PVT) variations, aging and radiation effects are considered for reliability testing.

The paper entitled “AI-based Building Management and Information System with Multi-agent Topology for an Energy efficient Building: Towards Occupants Comfort” presents Artificial Intelligence (AI) based building management and information system with multi-agent topology for the energy-efficient building. The multi-agent topology building management and information system are based on minimizing the energy consumption and maximizing the level of comfort by reducing the error between the actual parameters of the environment and the desired environmental parameters.

In the paper entitled “Added Noise in Oscillators Caused by the Transistor Base Emitter Breakdown Phenomenon” it is pointed out that when increasing the RF power level in transistor oscillators to achieve better phase noise performance a reverse voltage breakdown of the base emitter junction of the oscillator transistor can occur. This results in increased phase noise and long term-transistor degradation. Common transistor simulation models/simulators do not have this effect included in their library, so the simulations fail to predict correct oscillator behavior. In this paper, starting from common oscillator topologies and active devices, the critical waveforms are analyzed and related to the generated noise spectra. A theoretical explanation of the breakthrough process is given, and the simulation models are enhanced. Finally, recommendations are made how to avoid breakdown effects and the active device degradation in practical designs.

The paper entitled “Multi-user High Data Rate Indoor VLC Systems” the authors propose, design, and evaluation of the performance of an angle diversity transmitter (ADT) to achieve high data rate multi-user indoor visible light communication (VLC) systems. Proposed systems are examined with three different receivers: a wide-field of view (W-FOV) receiver, an angle diversity receiver (ADR) and an imaging diversity receiver (IMDR). A novel algorithm is introduced to eliminate the multi-user interference that is caused by line of sight (LOS) components, since these have a great impact on VLC systems performance. The effect of multi-user interference, mobility and diffuse reflections are considered in this work.

The authors of the paper titled “Robust Time Resource Management in Cognitive Radar Using Adaptive Waveform Design” present a framework for adaptive time resource management in Cognitive Radars. The authors propose an algorithm for time resource management that incorporates the adaptive waveform design capability of cognitive radars in order to improve the performance of radars for efficient time resource utilisation. After developing the equations for the first time for radar time resource management using adaptive waveform design, a practical algorithm is proposed and its performance is simulated and analysed. Using the proposed algorithm resulted in a more efficient management of time resources than the existing algorithms.

The article titled “Phased Sub-arrays Pattern Synthesis Method with Deep Sidelobe Reduction and Narrow Beam Width” describes a new array pattern synthesis method based on two uniformly sub-arrays controlled by a predetermined power factor to meet the future needs of 5G wireless communication. First, the outputs of these two scanned subarrays are added and subtracted, respectively, to produce the sum and difference patterns. Since the sidelobe structures of these two generated patterns are nearly identical, the difference pattern can be subtracted from the sum pattern to obtain an array pattern with drastically reduced sidelobes and narrowed beam width. Simulation results indicate that the proposed array pattern with power factor e = 0.5 can provide a sidelobe level of approximately −32 dB (i.e. an improvement about−19 dB with compared to that of the corresponding fully uniform array). In addition, the beam width of the proposed array is drastically reduced. Controlling the scanned angles of the two subarrays is also proposed as a method for achieving improved results.

The authors of the paper titled “Efficient Power Flow Management in Hybrid Renewable Energy Systems” propose an adaptive strategy for power flow management of a stand-alone hybrid renewable energy system (HRES) comprised of a wind turbine generator, photovoltaic cell, battery energy storage (BES), and load by optimising the gain of the PI controller in the battery storage system using the particle swarm optimization-based firefly algorithm (PSO-FA). A portion of the PSO algorithm is used to enhance the velocity and attractiveness of the firefly algorithm, thereby accelerating the rate of convergence of the PI controller. This control method improves the gain constant by generating control pulses for charging and discharging the BES system in order to maximise the use of renewable energy sources and stabilise the DC-link voltage. MATLAB/SIMULINK simulations reveal that conventional trial-and-error-based PI tuning yields high overshoot, whereas the proposed method yields improved performance with less overshoot.

The article titled “Planar Diplexer Design Using an Energetic Coupling Approach” describes a straightforward method for designing planar diplexers using an energetic coupling approach. Using a stepped impedance resonator (SIR), the intended diplexer generates two resonant frequencies at the desired pass bands. Utilizing the energetic coupling theory, suitable coupling factors are determined between the SIR and diplexer outputs. Two diplexers satisfying GSM and WLAN application frequencies have been fabricated and characterised in order to validate the proposed design method. One prototype has been created using microstrip technology, while the other has been created using a low-cost 3D printing multilayer process. In both instances, measurements and simulated responses correspond well.

The authors of the paper titled “A Novel Design of 28 nm Latch Type Sense Amplifier for Differential Voltage Enhancement” present an enhancement to the conventional latch type sense amplifier. Additional coupling effect is utilised to counteract the device coupling observed in the original design. Based on Monte-Carlo simulations under various operating conditions, the improved design exhibits a significant yield improvement. A modified layout pattern is also presented, demonstrating an alternative implementation of a sense amplifier to address the coupling effect with negligible power and area overhead.

“Design of a Class-F Power Amplifier with GaN Device Model and Reflection Data” describes a Class F power amplifier (PA) operating in the 2.5–2.7 GHz frequency band that is designed, fabricated, and tested using a gallium nitride high electron mobility transistor (GaN HEMT). The amplifier has a peak power-added efficiency (PAE) of 76.4% and a gain of 12.3 dB with an output power of 8.5W. This combination of high gain and high-efficiency operation over a broad frequency range allows the design to be utilised in a variety of commercial and defense applications where power consumption is a major design factor. Keysight's advanced design system (ADS) is utilised in the design and simulation process. The input matching network and harmonic termination circuits are designed using reflection data extracted from the transistor using a nonlinear model and harmonic balance analysis. The output matching circuit is designed using the obtained load pull data after the harmonic termination network design is completed. The design procedure is described in detail, and the input and output matching circuits are constructed in accordance with a particular method and sequence. The design based on reflection data is obtained under conditions of high signal strength. The ADS tool then defines and evaluates these data as a network termination.

In the paper “Investigation of Homo and Hetero-Junction Double-Gate Tunnel-FET-Based Adiabatic Inverter Circuits,” the authors compare the performance of adiabatic inverter circuits that use homo/heterojunction-based double-gate tunnel field-effect transistors (DG-TFETs). The static and dynamic adiabatic inverter circuits are constructed, and a sinusoidal power clock signal is used to run them. For static adiabatic inverter circuits, quasi-static energy recovery logic (QSERL), complementary energy path recovery logic (CEPAL), glitch-free cascadable adiabatic logic (GFCAL), and for dynamic adiabatic inverter circuits, clocked adiabatic logic (CAL), pass-transistor adiabatic logic (PAL), and single-phase source coupled adiabatic logic (SCAL) are taken into account. The performance of the circuit is evaluated based on its power dissipation and delay.

In the paper titled “Energy-Efficient Smart Wearable IoT Device for the Application of Collapse Motion Detection and Alert,” the authors propose an energy-efficient smart wearable IoT device that can detect the motion of the human body and, based on that, detect the collapsing motion and take immediate action by sending data to a cloud server via the internet, which will then send an SMS to the concerned person. ESP8266-01 is used as the communication channel, ADXL335 is used to calculate body motion, and ATTINY85 is used to reduce power consumption, resulting in a 220 mAh battery that lasts for a long time.

The authors of the paper titled “Phase Noise Impact on the Short-Term Frequency Stability of a Frequency Source” describe a method for estimating the Allan deviation values of a frequency source from its measured phase noise plot. Using the described method, the Allan deviations of a 10 MHz Rubidium Atomic Frequency Source (RAFS) on an IRNSS (Indian Regional Navigation Satellite System) satellite were calculated. During Integrated Spacecraft Testing of the IRNSS satellites, the estimated Allan deviation values obtained from the measured phase noise plot of the RAFS are compared with the measured Allan deviation values obtained by standard methods (such as the Standard Reference Source method and the 3-Corner Hat method).

“Maximum Power Extraction from a Wind Turbine Using Terminal Synergetic Control” describes a nonlinear controller with a wind speed estimator for a variable-speed wind turbine at wind speeds below the rated wind speed. A nonlinear controller is designed to account for the rapid variations in wind speed and system uncertainty. The objective of the nonlinear controller is to maximise wind energy extraction while minimising mechanical loads.

The authors of the paper “On the Miniaturization of Microstrip Ring-Hybrid Couplers Using Gielis Super Shapes” describe the design, development, and fabrication of compact microstrip ring-hybrid couplers. To obtain miniaturization, λ/4 microstrip lines in a conventional microstrip ring-hybrid are equivalently substituted with quarter-wavelength super shape transmission lines. In comparison to a conventional ring-hybrid, the results indicate that a 74% size reduction is possible. A sample prototype has been designed, manufactured, and tested for verification purposes. The manufactured compact ring-hybrid coupler operates with low amplitude and phase imbalances at 1.3 GHz. The performance of the presented coupler is validated by the acceptable agreement between measurement and stimulation results. The proposed ring-hybrid is small, straightforward, single-layered, inexpensive, and amenable to planar fabrication for use in contemporary communication systems.

Additional information

Notes on contributors

Shiban K Koul

Shiban K Koul is currently an emeritus professor at the Indian Institute of Technology, Delhi. He served as deputy director (Strategy and Planning) at IIT Delhi from 2012-2016 and mentor deputy director (Strategy & Planning, International Affairs) at IIT Jammu from 2018-2021. He also served as the Chairman of Astra Microwave Products Limited, Hyderabad from 2009-2019 and Dr R P Shenoy Astra Microwave chair professor at IIT Delhi from 2014-2019. His research interests include RF MEMS, high frequency wireless communication, microwave engineering, microwave passive and active circuits, device modelling, millimetre and sub-millimetre wave IC design, body area networks, flexible and wearable electronics, medical applications of sub-terahertz waves and reconfigurable microwave circuits including miniaturized antennas. He has successfully completed 38 major sponsored projects, 52 consultancy projects and 61 technology development projects. He has authored/co-authored 601 research papers, 22 state-of-the art books, 4 book chapters and 2 e-books. He holds 26 patents, 6 copyrights and one trademark. He has guided 30 PhD theses and more than 100 Master’s theses. He is a Life Fellow of IEEE and Fellow of INAE and IETE. He is the Chief Editor of IETE Journal of Research, Associate Editor of the International Journal of Microwave and Wireless Technologies, Cambridge University Press. He served as a Distinguished Microwave Lecturer of IEEE MTT-S for the period 2012-2014.

Recipient of numerous awards including IEEE MTT Society Distinguished Educator Award (2014); Teaching Excellence Award (2012) from IIT Delhi; Indian National Science Academy (INSA) Young Scientist Award (1986); Top Invention Award (1991) of the National Research Development Council for his contributions to the indigenous development of ferrite phase shifter technology; VASVIK Award (1994) for the development of Ka- band components and phase shifters; Ram Lal Wadhwa Gold Medal (1995) from the Institution of Electronics and Communication Engineers (IETE); Academic Excellence Award (1998) from Indian Government for his pioneering contributions to phase control modules for Rajendra Radar, Shri Om Prakash Bhasin Award (2009) in the field of Electronics and Information Technology, VASVIK Award (2012) for the contributions made to the area of Information, Communication Technology (ICT) and M N Saha Memorial Award (2013) from IETE.

His name has recently figured in the Scopus Elsevier top 2% Scientists under the Category “Year 2021”.Email: [email protected]

Arun Kumar

Arun Kumar is with the Centre for Applied Research in Electronics, Indian Institute of Technology, Delhi since 1997. He became professor in 2008 and has served as head of Centre for more than 7 years. He obtained the BTech, MTech and PhD degrees from Indian Institute of Technology Kanpur in 1988, 1990 and 1995, respectively. He was visiting researcher at the University of California, Santa Barbara, USA from 1994 to 1996 before joining IIT Delhi. His research interests are in digital signal processing, underwater and air acoustics, human and machine speech communication, and multi-sensor data fusion.

Professor Arun Kumar is an inventor on 10 granted US patents. He has guided 16 PhD theses and 180 Master’s theses. He has authored/co-authored 160 papers in peer reviewed journals and conferences. He has been project investigator/co-investigator for 72 funded R&D projects from industry and government. These projects have led to several technology and know-how transfers. Many of the technologies co- developed by him are deployed in the field and are in practical use. Professor Arun Kumar has served on several technical and organization committees of conferences, and on national level committees in electronics and defence fields. He is co-founder and director of a company that develop signal processing and AI based technologies and products for speech-based and multi-modal human and machine. He is currently Deputy Chief Editor of IETE Journal of Research. Email: [email protected]

Ranjan K Mallik

Ranjan K Mallik (FIETE, FIEEE, FIET, FTWAS, FNAE, FNA, FNASc, FASc) is an Institute Chair Professor in the Department of Electrical Engineering, Indian Institute of Technology (IIT) Delhi. He received the BTech degree from IIT Kanpur and the MS and PhD degrees from the University of Southern California, Los Angeles, all in electrical engineering. He has worked as a scientist in the Defence Electronics Research Laboratory, Hyderabad, India, and as a faculty member in IIT Kharagpur and IIT Guwahati. His research interests are in diversity combining and channel modelling for wireless communications, space-time systems, cooperative communications, multiple-access systems, power line communications, molecular communications, difference equations, and linear algebra. He is a recipient of the Shanti Swarup Bhatnagar Prize, the Hari Om Ashram Prerit Dr Vikram Sarabhai Research Award, the Khosla National Award, the IETE Ram Lal Wadhwa Award, the IEI-IEEE Award for Engineering Excellence, and the J C Bose Fellowship. He is a member of Eta Kappa Nu, and a fellow of IEEE, the Indian National Academies INAE, INSA, NASI, and IASc, TWAS, the West Bengal Academy of Science and Technology, IET (U.K.), IETE (India), The Institution of Engineers (India), and the Asia-Pacific Artificial Intelligence Association. He served as an area editor and an editor for the IEEE Transactions on Wireless Communications, and as an editor for the IEEE Transactions on Communications. He was a Technical Program Committee (TPC) Co-Chair for the Wireless Communications Symposium of IEEE GLOBECOM 2008 and IEEE ICC 2010, a TPC Co-Chair for the PHY Track of IEEE WCNC 2013, and a TPC Co-Chair for the Communication Theory Symposium of IEEE ICC 2021. He is currently Deputy Chief Editor of IETE Journal of Research. Email: [email protected]