rss_2.0Journal of Electrical Engineering FeedSciendo RSS Feed for Journal of Electrical Engineering of Electrical Engineering 's Cover triple-band implantable antenna for multitasking medical devices<abstract> <title style='display:none'>Abstract</title> <p>This paper presents a compact implantable antenna’s design, fabrication, and measurement for biotelemetry applications. The proposed design with the size of 255 mm<sup>3</sup> provides a triple-band operation that covers all the Medical Implant Communication Service (MICS: 402 MHz), Medical Device Radiocommunications Service (MedRadio: 405 MHz), and Industrial, Scientific, and Medical (ISM: 433, 915 and 2450 MHz) bands simultaneously. The compact structure with triple- band performance is essentially achieved by using a spiral-like radiator loaded with meandered and internal gear-shaped elements excited by a vertical coaxial probe feed. Also, the slots-loaded partial ground plane is utilized to improve impedance matching at the desired frequency bands. The design and analysis of the antenna were carried out using the Ansoft HFSS software in a homogenous skin model and the CST Microwave Studio in a realistic human model. The proposed antenna was fabricated to validate the simulated results, and characteristics of its return loss and radiation patterns were measured in minced pork meat. Moreover, realized gains and specific absorption rate (SAR) values of the antenna were numerically computed using the simulators. Based on the simulated and measured results, the proposed antenna performance was found to be comparable to the limited number of multiband implantable antenna designs reported in the recent literature.</p> </abstract>ARTICLE2022-07-11T00:00:00.000+00:00Robust boundary of stability and design of robust controller in uncertain polytopic linear systems<abstract> <title style='display:none'>Abstract</title> <p>This paper is devoted to design of a robust controller for an uncertain continuous-time linear polytopic system. The design procedure will take place in two steps. In the first step, we calculate the robust stability boundary of a closed loop system. Then on the basis of the result obtained in this way, we select a robust controller design method that accepts the calculated stability boundary. This procedure allows better implementation of the second step of the designed robust controller. Two examples of application of the proposed method follow finally, which illustrate its effectiveness.</p> </abstract>ARTICLE2022-07-11T00:00:00.000+00:00Analysing the shielding effectiveness of rectangular enclosure by determining aperture dimensions with particle swarm optimization<abstract> <title style='display:none'>Abstract</title> <p>Electromagnetic shielding enclosure is used to protect electronic circuits against external EMI. Aperture on the enclosure, which is necessary for various reasons such as mounting connector, ventilation attenuates shielding effectiveness (SE) of the enclosure. Enlarging enclosure dimensions makes SE get better. Yet, they canot be designed so large due to weight and dimension considerations for EV. When the dimensions of the shielding enclosure remain fixed and the aperture is to have a particular area, it is essential to optimize aperture dimensions to increase SE. In this paper, an optimization methodology based on PSO is designed to obtain the optimal SE for a particular dimension range. The study also provides a comparative analysis between designed optimization methodology and the one based on genetic algorithm in the literature. Obtained SE results indicate that the optimization methodology establishes a very good agreement with the results in the literature. Moreover, it has faster convergence and higher calculation accuracy than GA and it utilizes a smaller number of parameters thanks to its simplicity. Finally, it is concluded that through designed optimization methodology in this study, SE of the enclosure can be raised by optimizing aperture dimensions when the dimensions of shielding enclosure remain fixed.</p> </abstract>ARTICLE2022-07-11T00:00:00.000+00:00Waveguide power phase shifter with a ferrite circulator in S-band<abstract> <title style='display:none'>Abstract</title> <p>This paper presents the application of a phase shifter with a ferrite Y-circulator in band S. Global literature addresses primarily the basic types of power waveguide phase shifters, however, there has been minimal literature on a phase shifter that uses a ferrite circulator for phase shifting. The paper describes theoretical and practical results where a ferrite circulator is used to shift the phase. A power phase shifter utilizing a ferrite circulator could be used in power applications where high demands are placed on the phase shift accuracy with minimal power losses. The phase shift is handled by a tunable waveguide short circuit that is connected to the port 2 of the ferrite circulator. By changing the waveguide length, the phase is changed. The measured results are compared with theoretical calculations and evaluated. The proposed phase shifter utilizing the ferrite circulator has its advantages in its simple design, in the accuracy of the phase adjustment and in the speed of the tuning. Another great advantage is its quite low cost due to its simple design.</p> </abstract>ARTICLE2022-07-11T00:00:00.000+00:00Flawed implemented cryptographic algorithm in the Microsoft ecosystem<abstract> <title style='display:none'>Abstract</title> <p>With the continuous development in the electronic chip field, the requirements for the security of IT infrastructures are also increasing. The need for ever-increasing key lengths in cryptography to maintain security cannot grow indefinitely. One of the solutions in the field of cryptography for using shorter keys while maintaining security is cryptography based on the principle of elliptic curves. Asymmetric elliptic curve cryptosystems lies in solving the discrete logarithm problem on an elliptic curve. However, not only secure algorithm but also its correct implementation is important. In this paper, we discuss an incorrect implementation of the ECC algorithm in the crypt32.dll library (Microsoft Windows) and the possibilities of its misuse.</p> </abstract>ARTICLE2022-07-11T00:00:00.000+00:00Differential STBC NOMA: A new approach to downlink cooperative NOMA<abstract> <title style='display:none'>Abstract</title> <p>Due to the ability of massive connectivity, large bandwidth, and low latency, the non-orthogonal multiple access (NOMA) is considered the best approach for the 5th generation and beyond. However, the system performance is declined when the number of users is increased as each user will experience a great number of successive interface cancelations (SIC) in the downlink. To improve system performance, the NOMA is combined with cooperative communication which gives more spectral efficiency and fairness as compared to non-cooperative NOMA. Furthermore, space-time block code (STBC)- cooperative NOMA-based users experienced less SIC as compared to conventional CNOMA. This paper evaluates the performance of differential STBC-CNOMA with keeping in mind the imperfect SIC, channel state information (CSI), and timing synchronization between distributed cooperating users. The simulations results show that differential STBC-CNOMA gives high performance in terms of outage probability and sum rate analysis as compared to simple STBC-NOMA and conventional CNOMA. Hence, the differential STBC-CNOMA seems to be a better and more effective solution to enhance system performance.</p> </abstract>ARTICLE2022-07-11T00:00:00.000+00:00Influence of nanofiller concentration on polypropylene nanocomposites for high voltage cables<abstract> <title style='display:none'>Abstract</title> <p>Polymeric insulation for HVDC cable is attracting more attention in the modern power transmission system. Especially, the thermoplastic material is desirable for power cable insulation because of its recyclability and ease of processing. Thermoplastic material development is a good alternative to cross-linked polyethylene in the future. Polypropylene has the advantage of avoiding by-products during cable production, which can minimize space accumulation and degassing costs. Therefore, this study investigates the influence of nanofillers on the structural properties of isotactic polypropylene. In addition, the proposed composite material’s morphology, melting, dielectric permittivity, and breakdown strength are examined. Different weight percentages of inorganic nanofillers such as TiO<sub>2</sub> and ZnO are used to make nanocomposite thin films. With increasing filler concentration, the dielectric constant of the nanocomposite thin film increases. Apart from that, the dielectric loss of the TiO<sub>2</sub> nanocomposite thin film increases with weight percentage initially and it falls nearer to virgin material at a higher frequency. The breakdown strength of the nanocomposite materials shows a similar variation with filler concentration. TiO<sub>2</sub> is more resistant to deterioration than ZnO composite. Based on the results of the complete investigation, the TiO<sub>2</sub> nanocomposite is better suited for the insulation of HVDC cables.</p> </abstract>ARTICLE2022-07-11T00:00:00.000+00:00An efficient approach for sub-carrier allocation in MIMO MC-CDMA systems<abstract> <title style='display:none'>Abstract</title> <p>Sub-carrier allocation is an important process that directly affects users data and bit error rates for multi-user multi-carrier systems. The most important feature of the allocation process is to assign the sub-carriers to the active users in proportion to their needs to provide high-speed data transmission and reduce the bit error rates. In this study, an efficient subcarrier allocation algorithm has been proposed based on both capacity and fairness criteria for a MIMO MC-CDMA system, which is preferred as the multiplexing scheme in high data rate communication systems. The proposed algorithm achieves not only better error rate performance but also increases the total data rate compared to other algorithms</p> </abstract>ARTICLE2022-07-11T00:00:00.000+00:00Quadrant-based contour features for accelerated shape retrieval system<abstract> <title style='display:none'>Abstract</title> <p>Shape representation and retrieval are essential research topics of computer vision. This paper proposes a novel feature set to be used in content-based image retrieval systems. The proposed method is an extended version of our previous study which uses contour information of shapes. The previous study calculated the center of mass (CoM) of the shape. By taking the CoM as origin, we created imaginary vectors in every angular direction. From each vector, we extracted three features which are the number of intersections between vector and contour, average distance of intersection points to CoM, and standard deviation of these points. In this method, we extract novel features and decrease the size of the feature set to decrease the computation time. We divide the shape into quadrants and represent each quadrant by nine features. Each shape image is represented by a 4x9 feature vector. We tested the proposed method on MPEG-7 and ETH-80 datasets and compared it with the state-of-art. According to the results, our method decreased the computation time dramatically while giving a state-of-art level retrieval accuracy.</p> </abstract>ARTICLE2022-07-11T00:00:00.000+00:00Pixel level vacuum packaging for single layer microbolometer detectors with on pixel lens<abstract> <title style='display:none'>Abstract</title> <p>This paper presents a new approach for fabrication of single layer microbolometer detectors featuring pixel level vacuum packaging together with a lens on the pixel. The proposed lens structure can be used to increase the fill factor of the detector so that the pixel size can be decreased without decreasing the minimum feature size in the detector which is a problem in single layer microbolometers. The designs of the lens and the fabrication process of pixel level vacuum packaged microbolometer detector together with this lens are given in the framework of this study. The optical and mechanical simulations of the structure are performed. The radius of curvature of the lens is optimized to be 25 μm and it is shown that the condensing efficiency is 100% for 3 μm lens-detector distance. The deflection in the lens structure is found approximately as 0.8 nm in 1 atm environment pressure, showing that the proposed structure is durable. The proposed structure increases the fill factor to twice of the original value without decreasing the minimum feature size in the fabrication processes, resulting in the same amount of improvement in the performance of the detector. This approach can also be used to increase the yield and decrease the fabrication cost of single layer and also standard microbolometers with small pixel sizes, as it integrates the vacuum packaging in the fabrication steps.</p> </abstract>ARTICLE2022-07-11T00:00:00.000+00:00Decentralized controlled charging and vehicle-to-grid solution for voltage regulation in low voltage distribution systems<abstract> <title style='display:none'>Abstract</title> <p>This paper offers affordable controlled charging and a vehicle-to-grid solution that uses a non-smart power meter. Additional communication infrastructure in the low-voltage distribution network is not needed. Ladder logic control is developed to be easily implemented by any commercial programmable logic controller. The voltage values measured by the power meter and electric vehicle battery state of charge are the decision variables. A validity check based on the Monte Carlo method is conducted to test the effectiveness of the proposed solution. Electric vehicle charging requirements are simulated based on travel surveys. The results demonstrate the effectiveness of the proposed solution. The voltage level is kept within acceptable limits according to the power quality standard EN50160. One may argue that there is a mismatch between the rate of penetration of electric vehicles and the level of smart grid implementation, especially in developing countries with higher rates of wealth inequality. Therefore, the methodology presented in this paper can be seen as an affordable mid-way solution that will help distribution system operators in developing countries prepare for higher penetration levels of EVs.</p> </abstract>ARTICLE2022-05-14T00:00:00.000+00:00Study of subjective and objective quality assessment of infrared compressed images<abstract> <title style='display:none'>Abstract</title> <p>Given the lack of accessible infrared compressed images’ benchmarks annotated by human subjects, this work presents a new database with the aim of studying both subjective and objective image quality assessment (IQA) on compressed long wavelength infrared (LWIR) images. The database contains 20 reference (pristine) images and 200 distorted (degraded) images obtained by application of the most known compression algorithms used in multimedia and communication fields, namely: JPEG and JPEG-2000. Each compressed image is evaluated by 31 subjects having different levels of experience in LWIR images. Mean opinion scores (MOS) and natural scene statistics (NSS) of pristine and compressed images are elaborated to study the performance of the database. Five analyses are conducted on collected images and subjective scores, namely: analysis by compression type, analysis by file size, analysis by reference image, analysis by quality level and analysis by subject. Moreover, a wide set of objective IQA metrics is applied on the images and the obtained scores are compared with the collected subjective scores. Results show that objective IQA measures correlate with human subjective results with a degree of agreement up to 95 %, so this benchmark is promising to improve existing and develop new IQA measures for compressed LWIR images. Thanks to a real-world surveillance original images based on which we analyze how image compression and quality level affect the quality of compressed images, this database is primarily suitable for (military and civilian) surveillance applications. The database is accessible via the link: <ext-link ext-link-type="uri" xmlns:xlink="" xlink:href=""></ext-link>. As a follow-up to this work, an extension of the database is underway to study other types of distortion in addition to compression.</p> </abstract>ARTICLE2022-05-14T00:00:00.000+00:00Multi-UAV integrated HetNet for maximum coverage in disaster management<abstract> <title style='display:none'>Abstract</title> <p>This article presents a practical method for the 3D placement of a group of HetNet of unmanned aerial vehicles (UAV)-mounted base station (mBS) to offer maximum wireless connectivity and coverage for terrestrial users in a particular region. There are two ways to solve this issue. First, the ideal flying height for each UAV is determined based on the transmit power of the UAV, which offers the maximum ground coverage radius. Depending on their ideal flying altitudes and transmitting power, UAVs are divided into several categories. Given a collection of UAVs, the proposed approach identifies an optimum subset of the available UAVs and places them optimally in 3D to offer maximum coverage of the network for a particular area on the terrestrial ground while using the least amount of power. The results of the simulations show that the suggested approach is effective, and they also give important visions about the behavior of the HetNet supported UAVmBS cell subnetworks.</p> </abstract>ARTICLE2022-05-14T00:00:00.000+00:00Influence of temperature on detectable minimum rotation rate in i-FOGs using Er-doped SFSs<abstract> <title style='display:none'>Abstract</title> <p>In this study, an interferometric fiber optic gyroscope (I-FOG) model exploiting the double-pass backward (DPB) erbium-doped superfluorescent fiber source (SFS) with both thin-film filter (TFF) and fiber bragg grating (FBG) reflectors has been constructed and the effects of temperature variations on mean wavelength and detectable minimum rotation rate (DMRR) have been theoretically analyzed. the simulations corresponding with the relations between these parameters for temperature variations in the range of −60 °C to + 90 °C, have been performed using Matlab 2021b. DMRR variations have been found as 6.01 ppm/K and 3.83 ppm/K for the system with TFF, whilst they are 15.31 ppm/K and 1.58 ppm/K for the system with FBG.</p> </abstract>ARTICLE2022-05-14T00:00:00.000+00:00Observability, controllability and stability of a nonlinear RLC circuit in form of a Duffing oscillator by means of theoretical mechanical approach<abstract> <title style='display:none'>Abstract</title> <p>In this research article, observability, controllability and stability of a nonlinear RLC circuit with a nonlinear capacitor is investigated as a Duffing oscillator beginning with the dissipative equations of generalized motion using Lagrange-dissipative model ({L, D} -model briefly). The force related to the potential energy, equilibria, and their well known stability properties are given using state space approach. Prerequisite that the condition for a Legendre transform is fulfilled, for the same system, also Hamiltonian of the system is found. Using Hamiltonian and dissipation function, dissipative canonical equations are obtained. These equations are written in state space form. Then the equality to the same results obtained using the dissipative equations of generalized motion related equilibria and their stability was shown. Thus a Lyapunov function as residual energy function (REF) is justified in terms of stability of the overall system. As last step, different electrical and mechanical (physical) realization possibilities are discussed.</p> </abstract>ARTICLE2022-05-14T00:00:00.000+00:00Investigation of field free region formed by dual Halbach array for focused magnetic hyperthermia<abstract> <title style='display:none'>Abstract</title> <p>One of the challenges with magnetic fluid hyperthermia (MFH) is the limited control of magnetic nanoparticle (MNP) oscillations. To overcome this problem new approaches such as localization of MNP oscillations are being explored. In this study, we investigated the manipulation of field free region form by dual Halbach array displacements. We used finite element method simulation to examine gradient patterns in the workspace. Then, we created an experiment platform and took point probe measurements. As a result of the research, it was found that the field free region form can be manipulated by parametric distance changes of dual Halbach array. According to the findings, the field free region can expand and its shape can change from a point-like form to an ellipse-like surface by varying the distance between the arrays. The mapping of dual Halbach array generated gradient patterns for focused MFH was investigated for the first time in this study.</p> </abstract>ARTICLE2022-05-14T00:00:00.000+00:00Probabilistic three-phase power flow in a distribution system applying the pseudo-inverse and cumulant method<abstract> <title style='display:none'>Abstract</title> <p>A new, analytical approach using the cumulant method is proposed for the three-phase probabilistic power-flow (PPF) analysis. The approach to forming the sensitivity matrix is based on quantifying the pseudo-inverse instead of the inverse jacobian matrix, since it is commonly singular in a distribution power network. The results are compared with those obtained using the point-estimate method (PEM) and the Monte Carlo (MC) method, which is a commonly used reference method for the PPF analysis in a distribution power network.</p> </abstract>ARTICLE2022-05-14T00:00:00.000+00:00Spectral and energy efficiency trade-off in massive MIMO systems using multi-objective bat algorithm<abstract> <title style='display:none'>Abstract</title> <p>The rise in the usage of wireless communication increases the cellular communication by the same rate. With the continuation of this situation, the density in data traffic has the potential to cause problems in the near future. Coping with spectral efficiency-energy efficiency trade-off using massive MIMO systems is considered to be a reasonable solution to this problem. In this paper, cellular communication simulations were performed in cases with different number of users, number of antennas and transmission power of massive MIMO systems and then non-dominated solutions are determined. Multi-objective bat algorithm has been used to make this process much shorter. At last stage, performance of this algorithm is compared with various intelligent optimization algorithms and with ideal non-dominated solutions. When the algorithms are compared with each other, it is seen that multi-objective bat algorithm has the best performance among them.</p> </abstract>ARTICLE2022-05-14T00:00:00.000+00:00A novel principal component-based virtual sensor approach for efficient classification of gases/odors<abstract> <title style='display:none'>Abstract</title> <p>High-performance detection and estimation of gases/odors are challenging, especially in real-time gas sensing applications. Recently, efficient electronic noses (e-noses) are being developed using convolutional neural networks (CNNs). Further, CNNs perform better when they operate on a minimal size of vector response. In this paper, dimensions of the operational vectors have been augmented by using virtual sensor responses. These virtual responses are obtained from the principal components of the physical sensor responses. Accordingly, two sets of data are upscaled as a one-dimensional one. Another level of upscaling is further obtained by using the mirror mosaicking technique. Hence, with our proposed novel approach, the final vector size for CNN operations achieves a new dimension. With this upscaled hybrid dataset, consisting of physical and virtual sensor responses, a simpler CNN has achieved 100 percent correct classification in two different experimental settings. To the best of authors information, it is for the first time that an e-nose has been designed using a principal component-based hybrid, upscaled dataset and achieves 100 percent correct classification of the considered gases/odors.</p> </abstract>ARTICLE2022-05-14T00:00:00.000+00:00Smart DTC algorithm with automatic torque ripple adjustment<abstract> <title style='display:none'>Abstract</title> <p>The paper presents a direct torque control method with possibilities of automatic algorithm modification in terms of torque ripple reduction. The algorithm is based on the conventional switching table with an arbitrary number of discretized voltage levels allowing higher space-voltage resolution and consequently lower torque ripple. The number of available voltage levels can be easily changed and subsequently torque ripple reduced without the need to modify the conventional switching table. Appropriate algorithm modifications leading to torque ripple reduction are automatized, making this kind of control method simple, effective, and suitable for upcoming smart drives in the rapidly growing industry 4.0. Selective back electromotive force compensation can also be part of automatization with the aim to improve the drive dynamics. Experimental validation presented in the paper confirms improvements in torque ripple reduction retaining the simple and time-effective control structure of the induction machine DTC drive.</p> </abstract>ARTICLE2022-05-14T00:00:00.000+00:00en-us-1