rss_2.0Journal of Electrical Engineering FeedSciendo RSS Feed for Journal of Electrical Engineering of Electrical Engineering 's Cover MAC routing protocol for wireless sensor networks based on IEEE 802.11 ad hoc networks<abstract> <title style='display:none'>Abstract</title> <p>Due to the lack of efficient specified multi-hop routing protocol, IEEE 802.11 ad hoc networks have been in limited use for realizing wireless sensor networks where wireless sensors are dispersed in a region and each sensor can transmit its data to one another. We propose a novel MAC routing protocol for IEEE 802.11 wireless sensor networks, of which the service areas are extended by appropriately appointed pseudo-access points.</p> </abstract>ARTICLE2022-11-15T00:00:00.000+00:00Optimal design and low noise realization of digital differentiator<abstract> <title style='display:none'>Abstract</title> <p>This manuscript presents a design of a differentiator in the digital domain with its low noise realization. It manifests the minimization of the L<sub>1</sub> -error objective function by using a hybrid optimization technique consisting of the particle swarm and simulated annealing optimization algorithm. The obtained magnitude response provides a noteworthy approximation of the ideal differentiator with a minimal magnitude inaccuracy when compared with the existing designs. The realization structures are also investigated and compared in terms of the noise gain behavior.</p> </abstract>ARTICLE2022-11-15T00:00:00.000+00:00A new control strategy for harmonic reduction in photovoltaic inverters inspired by the autonomous nervous system<abstract> <title style='display:none'>Abstract</title> <p>This paper proposes a new inverter control strategy whose main purpose is to reduce the current harmonic distortion resulting from unnecessary control actions without sacrificing the system’s dynamic response. The brain’s capabilities to learn and react to stress are mimicked to generate control actions based on emotional cues. The model is based on the brain emotional learning based intelligent controller, to which an autonomous nervous system was added. The modified controller aims at separating the strategy during transient states from the one during steady states. The proposed method was compared to the PI controller, the PR controller, and a neural network-based controller on Matlab Simulink. It shows major improvements in terms of harmonic distortion and a complete removal of the inter-harmonics. It provides a good dynamic response in transient states and an immunity to irrelevant signal variations during the steady state, which results in an improvement in the harmonic production.</p> </abstract>ARTICLE2022-11-15T00:00:00.000+00:00An intelligent barrier using ultrasonic technology<abstract> <title style='display:none'>Abstract</title> <p>The article is devoted to the complete design of an intelligent barrier that uses piezoelectric ceramic transducers as transmitter of an acoustic signal and as a receiver. There is a relatively rich device base on the market for these transducers. These transducers are also not economically demanding. The barrier is composed of three identical bars. A continues wave rectangular signal generation is used for excitation of the converters on the transmitting side. The receiving side is more complex. A signal from the receiving transducer is first analog pre-processed and converted to logical values of 0 or 1. Subsequently, these signals are processed in a microcontroller system, evaluated and a possible alarm of a presence of an intruder is signaled using a display, a light-emitting diode and a piezoelectric siren. The display also shows the number of alarms. Some intelligence is added to the system by classifying a potential intruder. The functionality of the system is verified in a detail and discussed.</p> </abstract>ARTICLE2022-11-15T00:00:00.000+00:00Effects of metal layers on chemical vapor deposition of diamond films<abstract> <title style='display:none'>Abstract</title> <p>Diamond is recognized as one of the most promising wide bandgap materials for advanced electronic applications. However, for many practical uses, hybrid diamond growth combining metal electrodes is often demanded. Here, we present the influence of thin metal (Ni, Ir, Au) layers on diamond growth by microwave plasma chemical vapor deposition (MWCVD) employing two different concepts. In the first concept, a flat substrate (GaN) was initially coated with a thin metal layer, then exposed to the diamond MWCVD process. In the second concept, the thin diamond film was firstly formed, then it was overcoated with the metal layer and finally, once again exposed to the diamond MWCVD. It should be mentioned that this concept allows the implementation of the metal electrode into the diamond bulk. It was confirmed that the Ni thin films (15 nm) hinder the formation of diamond crystals resulting in the formation of an amorphous carbon layer. Contrary to this finding, the Ir layer resulted in a successful overgrowth by the fully closed diamond film. However, by employing concept 2 (<italic>ie</italic> hybrid diamond/metal/diamond composite), the thin Ir layer was found to be unstable and transferred into the isolated clusters, which were overgrown by the diamond film. Using the Au/Ir (30/15 nm) bilayer system stabilized the metallization and no diamond growth was observed on the metal layer.</p> </abstract>ARTICLE2022-11-15T00:00:00.000+00:00Graph based anomaly detection in human action video sequence<abstract> <title style='display:none'>Abstract</title> <p>In our paper, we have proposed to use graphs to detect anomaly in human action video. Although the detection of anomaly is a widely researched topic, but very few researchers have detected anomaly in action video using graphs. in our proposed method we have represented the smaller section (sub-section) of our input video as a graph where vertices of the graph are the space time interest points in the sub-section video and the association between the space time interest points exists. Thus, graphs for each sub section are created to look for a repeated substructure. We believe most of the actions inherently are repeated in nature. Thus, we have tried to capture the repetitive sub-structure of the action represented as a graph and used this repetitive sub-structure to compress the graph. If the compressed graph has few elements that have not been compressed, we suspect them as anomaly. But the threshold value takes care not to make the proposed method very much sensitive towards the few uncompressed elements. Our proposed method has been implemented on locally created “extended KTH” and “extended Weizmann” datasets with good accuracy score. The proposed method can also be extended for few more applications such as training athletes and taking elderly care.</p> </abstract>ARTICLE2022-11-15T00:00:00.000+00:00Comparison of methods for determining speech voicing based on tests performed on paired consonants and continuous speech<abstract> <title style='display:none'>Abstract</title> <p>Voicing is an important phonetic characteristic of speech. Each phoneme belongs to a group of either voiced or unvoiced sounds. We investigated and compared the performance of five algorithms widely used to estimate speech voicing. All algorithms were implemented in Matlab and tested on both short consonants and continuous speech. Phonetically paired consonants (voiced <italic>vs</italic> unvoiced) and parts of read speech from audio books were used in the experiments. The tuned harmonics-to-noise ratio method gave the best results in both situations, <italic>ie</italic> for consonants and continuous speech. Using this method, the overall voicing of Czech, Polish, Hungarian and English was investigated. Hungarian speech showed the highest proportion of voiced parts, approx. 75 %. In other languages, the proportion of voiced parts was around 70 %.</p> </abstract>ARTICLE2022-11-15T00:00:00.000+00:00Sidelobe level suppression for elliptical antenna arrays using modified SALP swarm algorithm<abstract> <title style='display:none'>Abstract</title> <p>In this study, a modified version of salp swarm algorithm (MSSA) is used to synthesize elliptical antenna arrays (EAAs). The original salp swarm algorithm (SSA) is an optimization algorithm inspired by the behavior of salps in nature, which is used to solve engineering problems. The main purpose of the synthesis in this study is to obtain an EAA pattern with low maximum sidelobe levels (MSLs) for a fixed narrow first null beamwidth (FNBW). For different examples, the amplitude and angular position values of the antenna array elements are considered as optimization parameters. To show the effectiveness of the MSSA, eight examples of EAAs with 8, 12, and 20 elements are given. The results obtained with MSSA are compared with those of the antlion optimization, symbiotic organizations search, flower pollination algorithm, and accelerated particle swarm optimization from the literature. It is clear from the numerical results that MSSA outperforms the other algorithms in terms of the suppression of MSL.</p> </abstract>ARTICLE2022-11-15T00:00:00.000+00:00Voltage THD limits for three- and single-phase multilevel inverters<abstract> <title style='display:none'>Abstract</title> <p>This paper deals with single and three phase multilevel inverters power quality. The voltage total harmonic distortion rate is an important criterion for choosing the number of inverter levels and checking compatibility with power quality requirements. In this study, the author raises an interesting issue related to the definition of voltage THD boundaries with upper and lower limits. The problem is reformulated, and a novel and more practical approach is developed for three- and single-phase multilevel inverters. Found upper and lower voltage THD limits are sufficiently verified with most known switching algorithms like sinusoidal modulation (SM) with phase disposition (PD), space vector modulation (SVM) and selective harmonic elimination (SHE). They are also valid for cascaded (H-Bridge), neutral point clamped (NPC) and flying capacitors (FC) multilevel inverters.</p> </abstract>ARTICLE2022-11-15T00:00:00.000+00:00A triple path noise cancellation LNA with transformer output using 45 nm CMOS technology<abstract> <title style='display:none'>Abstract</title> <p>A triple path dual resistive feedback noise cancellation (TP-DRNC) low noise amplifier (LNA) with transformer output presented which provides high gain, low noise figure (NF), and high figure of merit (F<sub>M</sub>). The analysis of triple path, dual resistive, gain, and NF have been discussed. The effect of various components used in the circuit have been analyzed and their optimized values are obtained which resulted in the high (F<sub>M</sub>). The combination of dual resistive feedback with triple path NC transformer output allowed for low NF and high gain. The proposed GPDK 45 nm complementary metal oxide semiconductor (CMOS) technology-based LNA offers a flat gain curve of 10.81 dB over the range of 1.6 GHz to 4.3 GHz, or 2.7 GHz bandwidth, and S<sub>11</sub> less than −9 dB. The input third order intercept point (IIP3) for the given bandwidth has value of 5.7 dBm, while the minimal NF achieved is 2.7 dB; (F<sub>M1</sub>) is 14.026 and (F<sub>M2</sub>) is 12.48. The proposed LNA’s layout with an o -chip transformer has an area of 0.01985 mm<sup>2</sup></p> </abstract>ARTICLE2022-11-15T00:00:00.000+00:00Model predictive control for distributed MPPT algorithm of cascaded H-bridge multilevel grid-connected PV inverters<abstract> <title style='display:none'>Abstract</title> <p>This paper concentrates on an algorithm with model predictive control for current and distributed MPPT for cascaded H-bridge multilevel photovoltaic (PV) inverter applications. In conventional method, in each sampling period, a discrete-time model is employed to predict the current future values for all vectors of voltage. The voltage vector will be approved if it minimizes the cost function. Because multilevel inverter has so many available voltage vectors, there is a large quantity of calculations, hence it makes difficult in implementing the normal control method. A varied control strategy that extensively decreases the calculations volume and eliminating common-mode voltage is proposed. To raise the PV modules performance and enlarge the systems power, a distributed maximum power point tracking (MPPT) control scheme for each phase of multilevel inverter is offered, that allows its DC-link voltage to be regulated separately. The recommended approach is double-checked by using a model simulated in MATLAB-Simulink software.</p> </abstract>ARTICLE2022-09-22T00:00:00.000+00:00Analytical method for joint optimization of FFE and DFE equalizations for multi-level signals<abstract> <title style='display:none'>Abstract</title> <p>Channel equalization is the efficient method for recovering distorted signal and correspondingly reducing bit error rate (BER). Different type of equalizations, like feed forward equalization (FFE) and decision feedback equalization (DFE) are canceling channel effect and recovering channel response. Separate optimization of tap coefficients for FFE and DFE does not give optimal result. In this case FFE and DFE tap coefficients are found separately and they are not collaborating. Therefore, the final equalization result is not global optimal. In the present paper new analytical method for finding best tap coefficients for FFE and DFE joint equalization is introduced. The proposed method can be used for both NRZ and PAM4 signals. The idea of the methodology is to combine FFE and DFE tap coefficients into one optimization problem and allow them to collaborate and lead to the global optimal solution. The proposed joint optimization method is fast, easy to implement and efficient. The method has been tested for several measured channels and the analysis of the results are discussed.</p> </abstract>ARTICLE2022-09-22T00:00:00.000+00:00A potential flooding version number attack against RPL based IOT networks<abstract> <title style='display:none'>Abstract</title> <p>Routing protocol for low power and lossy networks (RPL) has been proposed for power, memory, and processing constrained devices. Owing to their constrained, RPL-based networks are exposed to a wide range of security attacks that mainly include control message tampering. In this paper we propose and study a modified version number attack, based on flooding the network by falsified incremented version numbers. The obtained results show that the modified attack led to an immense increase in the overhead, 1426%, compared with the attack-free case, and an increase of 182 % in the total energy consumption. When it comes to PDR a degradation to 4.7% has been recorded, affecting the reliability of the network. On the other hand, the latency also showed an increase from 0.24 s in the attack-free case to 0.89 s, which is mainly due to the high congestion created by the attack.</p> </abstract>ARTICLE2022-09-22T00:00:00.000+00:00Active-clamped flyback DC-DC converter in an 800V application: Design notes and control aspects<abstract> <title style='display:none'>Abstract</title> <p>This paper presents findings for active-clamped flyback (ACF) DC-DC converter 57 W used as an auxiliary power-supply of a wireless inductive-charging system 800 V. Measurements of magnetizing and leakage inductances for three transformers demonstrated how big differences between them could be depending on chosen vendor. Comparison of simulated and measured Bode plots showed that, even when those plots were not matched, one could design a compensator that ensures stable operation. Evaluation of cross-regulation when output with low power (9.62 % of total) was regulated showed that such approach was feasible too. The <italic>switching frequency vs output-power</italic> and <italic>drain-source voltage of switch vs output-power</italic> graphs are presented for the first time. Comparison of bandwidth, phase-margin and gain-margin <italic>vs</italic>input-power, between the ACF and conventional flyback converter were discussed too. Those quantities were changeable with load and input-voltage as expected. The conventional flyback converter in DCM has higher bandwidth than the ACF which resulted in lower phase- and gain-margins. That showed that it cannot have the same compensator as an ACF.</p> </abstract>ARTICLE2022-09-22T00:00:00.000+00:00Robust adaptive beamforming using modified constant modulus algorithms<abstract> <title style='display:none'>Abstract</title> <p>This paper addresses the self-nulling phenomenon also known as the self-cancellation in adaptive beamformers. Optimum beamforming requires knowledge of the desired signal characteristics, either its statistics, its direction-of-arrival, or its response vector. Inaccuracies in the required information lead the beamformer to attenuate the desired signal as if it were interference. Self-nulling is caused by the desired signal having large power (high SNR) relative to the interference signal in case of the minimum variance distortion less response beamformer, and low power desired signal in the case of the constant modulus algorithm (CMA) beamformer, which leads the beamformer to suppress the desired signal and lock onto the interference signal. The least-square constant modulus algorithm is a prominent blind adaptive beamforming algorithm. We propose two CMA-based algorithms which exploit the constant modularity as well as power or DOA of the desired signal to avoid self-nulling in beamforming. Simulations results verify the effectiveness of the proposed algorithms.</p> </abstract>ARTICLE2022-09-22T00:00:00.000+00:00High-performance tri-band graphene plasmonic microstrip patch antenna using superstrate double-face metamaterial for THz communications<abstract> <title style='display:none'>Abstract</title> <p>Recently, graphene-patch antennas have been widely used in communication technology, especially in THz applications due to the extraordinary properties of graphene material. Herein, a graphene-based rectangular microstrip patch antenna is designed on an FR4 substrate material (ɛ<sub>r</sub> = 4.3). A single and double-faced superstrate MTM is placed upon the radiating patch for di erent purposes, such as enhancing the overall antenna performance, protecting the patch from environmental jeopardies, and generating a multiband resonance frequency. A single face superstrate triangle SRR unit was used to produce a dual-band frequency at 3.5 and 4.331 THz. The <italic>S</italic><sub>11</sub> of the dual-band structure is achieved to be −26.78 dB and −46.25 dB with a bandwidth of 400 GHz and 460 GHz, respectively. The double face superstrate MTM unit cell of the triangle SRR printed on the opposite face gives another resonant frequency, so, triple frequency bands of 2.32, 3.35, and 4.38 THz with a wide impedance bandwidth of 230, 520, and 610 GHz, were generated, respectively. The double-face superstrate MTM not only enhances the antenna performance but also generates another resonant frequency that could be used in the next 6G communications. The proposed antenna is designed and optimized using two commercial 3D full-wave software, CST Microwave Studio and Ansoft HFSS, to validate the results.</p> </abstract>ARTICLE2022-09-22T00:00:00.000+00:00Model of fractional-order resonant wireless power transfer system for optimal output<abstract> <title style='display:none'>Abstract</title> <p>Wireless Power Transfer (WPT) technology has recently gained popularity in applications and research topics. It enables the transfer of electrical energy from a source to a load without connecting wires physically. The WPT system is commonly studied classically using integer order capacitors and inductors. Nonetheless, such integer order based systems have drawbacks, such as low output power, poor transmission efficiency and sensitivity to parameter variations. This paper proposes a fractional order resonant WPT circuit whereby both the transmitting and receiving ends are composed of a fractional capacitor and inductor to overcome such problems. In this paper, the overall performance is studied based on its output power and efficiency considering a series-parallel topology. The effect of fractional order in fractal elements will be analyzed to observe the optimal combination of components to achieve the maximum output power with higher efficiency. Through a comparative analysis of the results, several combinations of circuit parameters can provide a theoretical understanding for implementing an experimental system.</p> </abstract>ARTICLE2022-09-22T00:00:00.000+00:00Energy estimation of QCA circuits: An investigation with multiplexers<abstract> <title style='display:none'>Abstract</title> <p>Quantum-dot Cellular Automata (QCA) is a rival to complementary-metal-oxide-semiconductor (CMOS)-based technology and one of the most cutting-edge nano-scale technologies. The multiplexer is a fundamental component in the fields of nano communication and nano computation. The investigative item of this article is the QCA multiplexer, and a handful of the best multiplexers were chosen as samples for the current experiment. The QCA layouts were designed in the QCADesigner-2.0.3 simulation engine environment, and the best one was reported after successfully experimenting on a total of eight samples. The co-ordinate-based energy was estimated using QCADesigner-E (QDE), and the non-adiabatic energy waste was investigated using QCAPro. According to the coordinates-based technique, the overall energy waste of the best energy-saving QCA multiplexer is 5.90 meV, with an average energy loss per cycle of 0.537 meV. Another approach, QCAPro-based, was used to estimate the energy loss at three different levels of tunneling at a constant temperature, yielding an overall energy loss of approximately 12 to 15 meV for the energy-efficient multiplexers..</p> </abstract>ARTICLE2022-09-22T00:00:00.000+00:00Spam filter based on geographical location of the sender<abstract> <title style='display:none'>Abstract</title> <p>Spam annoys users and poses a security threat. This article proposes a spam filter based on geographical location of the sender determined by IP geolocation. This filter was implemented as a plugin to the SpamAssassin anti-spam software. The plugin allows to define a penalty score for specific countries sending spam. The proposed filter was tested on a dataset of 1500 e-mails consisting of 1200 spam and 300 legitimate e-mails. The Matthews correlation coefficient of the filter has a value of 0.222. This indicates that the proposed spam filter contributes to the correct spam filtering.</p> </abstract>ARTICLE2022-09-22T00:00:00.000+00:00A concept for discrimination of electrical fault from cyber attack in smart electric grid<abstract> <title style='display:none'>Abstract</title> <p>This letter proposes a concept to discriminate an electrical fault from a cyber attack in the modern power system. A cyber attack factor is introduced which may mislead the bus voltage stability virtually at load buses. The proposed cyber attack models are validated by executing multiple cyber attacks at a time on Western system coordinating council (WSCC) 9 bus test power system by using Siemens PSS/E and MATLAB softwares. Further, the impact of electrical fault and cyber attack on the WSCC 9 bus test power systems voltage stability has been analysed to develop a discrimination algorithm in reference to chosen load index. Despite its simplicity, the proposed discrimination algorithm is robust, accurate and quite suitable to develop intelligent measures for mal-operations against cyber attacks in the smart electric grid.</p> </abstract>ARTICLE2022-09-22T00:00:00.000+00:00en-us-1