rss_2.0Journal of Electrical Engineering FeedSciendo RSS Feed for Journal of Electrical Engineering of Electrical Engineering Feed of partial discharge ultrasonic signal of insulation bar in large motor based on GMC-wavelet<abstract> <title style='display:none'>Abstract</title> <p>In view of the bad operation environment of large motor, which often suffers from various strong noise interference, the partial discharge ultrasonic signal is often annihilated, which makes it difficult to detect and analyse. A de-noising method based on generalized minimax concavity (GMC) and wavelet for partial discharge (PD) ultrasonic signal is proposed. GMC is used to enhance the sparsity of PD ultrasonic signal and eliminate the high-frequency noise signal at the same time. Then the residual high-frequency sparse noise and low-frequency noise of the former are de-noised again combined with wavelet. Finally, the signal is reconstructed to achieve the purpose of de-noising the original PD ultrasonic signal with noise. Compared with ℓ<sub>1</sub> -norm method, GMC method, wavelet method and ℓ<sub>1</sub> -norm-wavelet method, the simulation results show that based on time domain analysis, the de-noising effect of the proposed method is obviously better than the other four methods. The SNR and MSE of the former are better than those of the latter. In addition, the insulation bar discharge model of large motor is constructed to obtain the actual PD ultrasonic signal, which further verifies its effectiveness, and its de-noising effect is also better than the four methods. This method can not only enhance the sparsity of the target signal and improve the estimation accuracy, but also achieve the de-noising effect, while retaining the effective information of PD ultrasonic signal characteristics. This method can provide new ideas for other types of PD signal de-noising, and lay the foundation for later feature analysis.</p> </abstract>ARTICLEtrue pattern orthogonal interleaver set for interleave division multiple access based, non orthogonal multiple access schemes: Beyond 5G perspective<abstract> <title style='display:none'>Abstract</title> <p>This communication suggests an orthogonal interleaver set for interleave division multiple access (IDMA) based non orthogonal multiple access (NOMA) schemes from beyond 5G viewpoint to support enormous increase in user count. The method generates an orthogonal interleaver set by providing two mother interleavers as seed to generate other users’ interleaving patterns progressively. The key feature of the proposed scheme is that it reduces implementation complexity and memory requirement at the base station, while implementing iterative multiuser detection (MUD), which most of the interlaever designs suggested in literature do not consider. It provides additional security to the user data due to progressively changing mother interleavers’ pattern along with the conventional purpose of providing unique identity for individual users in the system. The proposed orthogonal interleaver set is tested through simulations under multiple IDMA system configurations. It has been observed that it preserves the bit error rate (BER) performance of the IDMA scheme along with the optimal implementation complexity and minimal information exchange requirement between base station and mobile station to share the interleaver design.</p> </abstract>ARTICLEtrue channel convolutive blind source separation for LFM radar signals<abstract> <title style='display:none'>Abstract</title> <p>We propose a single channel blind source separation algorithm for convolutively mixed linear frequency modulation (LFM) signals based on smoothed Wigner-Ville distribution (SWVD) time-frequency analysis, Canny edge detection, and Hough transform detection. First, the SWVD time-frequency analysis diagram is obtained as an image based on the LFM time-frequency characteristics. Second, Canny edge detection is performed on the image. Then, Hough transform is used to detect the characteristic parameters of the linear signal. Finally, the source signal is recovered. The simulation results show that the algorithm is effective for single channel detection and extraction of convolutively mixed LFM signals.</p> </abstract>ARTICLEtrue mapping techniques for processors with very long instruction word architectures<abstract> <title style='display:none'>Abstract</title> <p>This paper presents an instruction mapping technique for generating a low-level assembly code for digital signal processing algorithms. This technique helps developers to implement retargetable kernel functions with the performance benefits of the low-level assembly languages. The approach is aimed at exceptionally long instruction word (VLIW) architectures, which benefits the most from the proposed method. Mapped algorithms are described by the signal-flow graphs, which are used to find possible parallel operations. The algorithm is converted into low-level code and mapped to the target architecture. This process also introduces the optimization of instruction mapping priority, which leads to the more effective code. The technique was verified on selected kernels, compared to the common programming methods, and proved that it is suitable for VLIW architectures and for portability to other systems.</p> </abstract>ARTICLEtrue fundamental approach: E-polarized electromagnetic wave diffraction by two dimensional arbitrary-shaped objects with impedance boundary condition<abstract> <title style='display:none'>Abstract</title> <p>In the present study, a new methodology in computational electromagnetics is developed for two-dimensional arbitrarily-shaped objects with impedance boundary conditions. The proposed approach investigates the E-polarized electromagnetic diffraction by a two-dimensional object with the Leontovich boundary condition. The scattered electric and magnetic fields are expressed as the convolution integral of the corresponding Green’s function and the current induced on the obstacle surface. After obtaining integral equations by applying the boundary condition, the integral equations are solved as in the case of the method of auxiliary sources (MAS) which is a well-known method in computational electrodynamics. The results are compared with first, different methods such as the method of moments (MoM), orthogonal polynomials (OP), and second, different boundary conditions such as Dirichlet, Neumann, and fractional boundary conditions. Some results are also obtained for the different shape scatterers at some values of the surface impedance.</p> </abstract>ARTICLEtrue of closed-form equations for force between cylindrical magnets over wide range of volume, aspect ratio, and force<abstract> <title style='display:none'>Abstract</title> <p>Four types of magnets were used in this study: neodymium NdFeB (grade N35 and N52), ferrite (Y10), and samarium-cobalt SmCo (XG30 2:17). They were chosen to represent a wide range of volumes from 0.035 to 19 cm<sup>3</sup> (540 times), radius <italic>R</italic> from 1.5 to 12.5 mm (8 ×), length L from 0.5 to 40 mm (80 ×), aspect ratio L/R from 0.051 to 17 (330 ×), and contact forces from 0.2 to 250 N (over 1000 ×). The study shows that previously reported closed-form equations are valid only at large distances (small forces). At short distances (large forces) the calculated force diverges to infinity or the accuracy depends on the aspect ratio, and some equations fail more than others. A new equation is proposed as a small modification of a previously known function, which provides reasonable behaviour over the whole studied range. However, the accuracy is unknown in a general practical case, because theoretical calculations do not take into account imperfections of real magnets, so there is no single absolute reference.</p> </abstract>ARTICLEtrue ultra-wideband antenna array equipped with thin frequency selective surface for high-gain applications<abstract> <title style='display:none'>Abstract</title> <p>This article begins with an explanation of a frequency selective surface, also known as an FSS, which is used to increase gain across a wide frequency range. The proposed unit design is a modified combination of circular and square elements with two cross dipoles and a T-type structure at the inner side. In the second step of the process, a single wideband antenna that covers the same range as FSS is designed and then analyzed in terms of its gain and radiation patterns. After that, an antenna array was built using the same solo structure in order to take advantage of the benefits that come with using an array system. The array is made up of elements that are CPW fed. A ground-backed T-shaped power divider network with additional shorting pins is used to supply power to the entire array. In the fourth step, an array of the FSS unit cell has been positioned beneath the UWB solo antenna and its array in order to investigate the possibility of improved gain and radiation pattern. The FSS equivalent lumped circuit model is presented here for validation purposes. It has been determined that the results of the experiment and the simulation are consistent with one another. In contrast to the structures that have been reported in the past, the newly developed model possesses a greater bandwidth, a higher gain, and a lower profile.</p> </abstract>ARTICLEtrue application of the key term separation principle<abstract> <title style='display:none'>Abstract</title> <p>The paper deals with a new application of the key term separation principle in identification of nonlinear dynamic systems. A multiplicative form of this operator decomposition technique is proposed and applied to the Wiener model. The resulting mathematical model is linear in both the linear and the nonlinear block parameters. Illustrative examples are included.</p> </abstract>ARTICLEtrue analysis of coupled split-ring resonators<abstract> <title style='display:none'>Abstract</title> <p>The coupling between closely spaced split-ring resonators, when employed as sub-components of electromagnetic structures, is an important feature often leveraged upon to provide bulk material properties. In its contribution, this paper employs characteristic-mode analysis (CMA) to examine modal interactions intrinsic to the coupling between a pair of split-ring resonators. The analysis reveals the influence of feed impedance and rotational orientation of a pair of coupled SRRs on the excited resonant modes, which, in turn, determine the power transfer levels between both SRRs and the frequencies at which these occur. The insights provided suggest the aptness of rotational orientation and feed impedance as critical design parameters for the realization of SRR-based magneto-inductive waveguides and wireless power transfer setups.</p> </abstract>ARTICLEtrue length limited CCSDS convolutional codes for optical communications<abstract> <title style='display:none'>Abstract</title> <p>This paper presents the construction of RLL-ECCs (run length limited error control codes) from three selected ECCs specified by Consultative Committee for Space Data Systems (CCSDS) for optical communications. The RLL-ECCs obtained present a practical alternative to CCSDS codes with pseudo-randomizers. Their advantage is that the maximal run lengths of equal symbols in their codeword sequences are guaranteed, which is not the case if the common approach with pseudo-randomizers is used. The other advantages are that no additional redundancy is introduced into encoded codewords and that the encoding and decoding procedures of the original error control CCSDS codes do not have to be modified in the following cases: Firstly, if hard decoding is used and the transmission channel can be modeled as a BSC (binary symmetric channel) and secondly, if soft decoding and coherent BPSK (binary phase shift keying) modulation is used and the appropriate transmission channel model is an AWGN (additive white Gaussian noise) channel.</p> </abstract>ARTICLEtrue 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>ARTICLEtrue 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>ARTICLEtrue 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>ARTICLEtrue 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>ARTICLEtrue 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>ARTICLEtrue 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>ARTICLEtrue 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>ARTICLEtrue 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>ARTICLEtrue 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>ARTICLEtrue 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>ARTICLEtrue