Elektronika ir Elektrotechnika http://eejournal.ktu.lt/index.php/elt <div>ELEKTRONIKA IR ELEKTROTECHNIKA is&nbsp;a peer-reviewed bimonthly research journal of Kaunas University of Technology.</div> <p>The research journal ELEKTRONIKA IR ELEKTROTECHNIKA publishes previously unpublished manuscripts that will have a high impact in the field of electronics and electrical engineering. It targets not only certain field specialists, but the wider public also.</p> Kaunas University of Technology en-US Elektronika ir Elektrotechnika 1392-1215 <p>Copyright terms are indicated in the Republic of Lithuania Law on Copyright and Related Rights, Articles 4-37.</p> Title http://eejournal.ktu.lt/index.php/elt/article/view/24347 Elektronika ir Elektrotechnika Copyright (c) 2019 Elektronika ir Elektrotechnika 2019-10-06 2019-10-06 25 5 1 1 10.5755/j01.eie.25.5.24347 Editorial Board http://eejournal.ktu.lt/index.php/elt/article/view/24348 Elektronika ir Elektrotechnika Copyright (c) 2019 Elektronika ir Elektrotechnika 2019-10-06 2019-10-06 25 5 2 3 10.5755/j01.eie.25.5.24348 A Novel Information Fusion Method for Vision Perception and Location of Intelligent Industrial Robots http://eejournal.ktu.lt/index.php/elt/article/view/20587 <p>An improved SURF (Speeded-Up Robust Feature) algorithm is proposed to deal with the time-consuming and low precision of positioning of industrial robot. Hessian matrix determinant is used to extract feature points from the target image and a multi-scale spatial pyramid is constructed. The location and scale value of feature points are determined by neighbourhood non-maximum suppression method. The direction of feature points is defined as directional feature descriptors by the binary robust independent elementary feature (BRIEF). The progressive sample consensus (PROSAC) is used to carry out second precise matching and remove mismatching points based on the Hamming distance. Then, an affine transformation model is established to describe the relationship between the template and target images. Centroid coordinates of the target can be obtained based on the affine transformation. Comparative tests were carried out to demonstrate that the proposed method can effectively improve the recognition rate and positioning accuracy of the industrial robots. The average time consuming is less than 0.2&nbsp;s, the matching accuracy is 96&nbsp;%, and the positioning error of the robot is less than 1.5&nbsp;mm. Therefore, the proposed method has practical application importance.</p> Shoufeng Jin Qiangqiang Lin Jian Yang Yu Bie Mingrui Tian Zhixiong Li Copyright (c) 2019 Elektronika ir Elektrotechnika 2019-10-06 2019-10-06 25 5 4 10 10.5755/j01.eie.25.5.20587 Minimizing Capacitance Value of Interleaved Power Factor Corrected Boost Converter for Battery Charger in Electric Vehicles http://eejournal.ktu.lt/index.php/elt/article/view/24349 <p>A dynamic voltage compensator (DVC) technique is presented for the minimizing of the capacitance value of the interleaved power factor corrected (PFC) boost converter for the battery charger in electric vehicles. This technique is based on eliminating the ripple on the capacitor by creating a voltage in the opposite direction as well as the amount of ripple on the capacitor. With the proposed method, the capacitance value is reduced by approximately five times. Reducing the size of the capacitor also provides the use of film-capacitors with a longer life. The other contribution of this study is designing a faster and more stable fully-digital control system, instead of the commonly used analogue controller of interleaved PFC boost converter. A 3.3&nbsp;kW interleaved PFC boost converter is designed to verify the effect of the designed dynamic voltage compensator and digital controller.</p> Omer Turksoy Unal Yilmaz Ahmet Teke Copyright (c) 2019 Elektronika ir Elektrotechnika 2019-10-06 2019-10-06 25 5 11 17 10.5755/j01.eie.25.5.24349 Hardware Acceleration of Sparse Oblique Decision Trees for Edge Computing http://eejournal.ktu.lt/index.php/elt/article/view/24351 <p>This paper presents a hardware accelerator for sparse decision trees intended for FPGA applications. To the best of authors’ knowledge, this is the first accelerator of this type. Beside the hardware accelerator itself, a novel algorithm for induction of sparse decision trees is also presented. Sparse decision trees can be attractive because they require less memory resources and can be more efficiently processed using specialized hardware compared to traditional oblique decision trees. This can be of significant interest, particularly, in the edge-based applications, where memory and compute resources as well as power consumption are severely constrained. The performance of the proposed sparse decision tree induction algorithm as well as developed hardware accelerator are studied using standard benchmark datasets obtained from the UCI Machine Learning Repository database. The results of the experimental study indicate that the proposed algorithm and hardware accelerator are very favourably compared with some of the existing solutions.</p> Predrag Teodorovic Rastislav Struharik Copyright (c) 2019 Elektronika ir Elektrotechnika 2019-10-06 2019-10-06 25 5 18 24 10.5755/j01.eie.25.5.24351 Fractional-Order Phase Shifters with Constant Magnitude Frequency Responses http://eejournal.ktu.lt/index.php/elt/article/view/24352 <p>This contribution presents and experimentally analyzes the idea how to reach the constant magnitude as well as the phase response in the fractional-order (FO) phase when shifting two-ports. The straightforward method employing the automatic gain control circuit (AGC) in a cascade after so-called constant phase block approximating FO integrator or differentiator is studied. The variable gain amplifier utilized in AGC and simple RC-based FO constant phase elements (approximating capacitors with order alpha = 1/4 and alpha = 1/2 as an example) connected in the feedback of operational amplifier-based integrator are established in the experimental setup. The operation indicated in three decades (between 100&nbsp;Hz and 100&nbsp;kHz) is evaluated. The known solutions of the standard FO phase shifting circuits are discussed and generally compared with the features obtained in this paper, together with the supposed effects of AGC on their performances.</p> Roman Sotner Lukas Langhammer Jan Jerabek Peter A. Ushakov Tomas Dostal Copyright (c) 2019 Elektronika ir Elektrotechnika 2019-10-06 2019-10-06 25 5 25 30 10.5755/j01.eie.25.5.24352 Performance Comparison of Evolutionary Algorithms in the Design of a Hand-Pump Shape Microstrip Antenna for 5G Applications http://eejournal.ktu.lt/index.php/elt/article/view/24353 <p>In this work, a single element hand-pump shape microstrip patch antenna working at 3.4&nbsp;GHz–3.8&nbsp;GHz for future 5G applications is proposed. The overall dimensions of the proposed antenna are 34&nbsp;mm × 28&nbsp;mm × 1.6&nbsp;mm. In order to obtain the desired bandwidth, three rectangular slots are etched from the radiating element along with the utilization of the defected ground structure. To optimize the geometrical parameters of the proposed antenna, performance comparison of various optimization techniques viz. Particle Swarm Optimization, Bat algorithm, Differential Evolution, and Artificial Bee Colony algorithm are presented. The performance of the antenna is analyzed with the help of S-parameter, gain, and radiation efficiency. The proposed antenna is resonant at 3.6&nbsp;GHz with an impedance bandwidth of 400&nbsp;MHz and the radiation efficiency of 74&nbsp;%, which is quite appropriate for a single element 5G antenna. Further, the suggested antenna is fabricated and experimentally tested for the validation of results.</p> Navneet Kaur Surbhi Sharma Jaswinder Kaur Copyright (c) 2019 Elektronika ir Elektrotechnika 2019-10-06 2019-10-06 25 5 31 36 10.5755/j01.eie.25.5.24353 Research on Ground of Penetrating Radar in the Coal Mine Detecting: A Case Study of Application in Huaibei Coal Mine http://eejournal.ktu.lt/index.php/elt/article/view/24354 <p>Although many geophysical techniques have been used to detect the disaster geological anomalous body in the Huaibei coal mine company, there are still many mining disasters happening. The main reason is that the coal seam is rich of water in Huaibei coal areas. If the ground water connects with tunnels, it will cause the flood to collapse the coal seam. However, these dangerous geological bodies usually are very hided from the viewpoint of traditional electromagnetic and seismic methods. Due to the great difference of permittivity between the water-bearing rock and the surrounding rock, the high frequency electromagnetic wave can be received by a Ground Penetrating Radar (GPR) to detect the water-bearing rocks. Hence, we try to employ the high frequency electromagnetic wave to detect the water-bearing rock, which frequently results in a coal mining disaster. Firstly, the numerical simulations based on the theory research and its` effectivity analysis are done. Then, the method is used for the coal mine of Huaibei Company. Finally, the comparison between the detected results and the geological drilling information indicates the detection effectiveness of the GPR (Ground Penetrating Radar) in the coal mine tunnel.</p> Yongsheng Ma Jinsong Shen Benyu Su Yanyan Ma Qilong Sun Copyright (c) 2019 Elektronika ir Elektrotechnika 2019-10-06 2019-10-06 25 5 37 42 10.5755/j01.eie.25.5.24354 Quality Evaluation of Voice Transmission Using BPL Communication System in MV Mine Cable Network http://eejournal.ktu.lt/index.php/elt/article/view/24355 <p>This article presents results of a quality evaluation study, considering voice transmission in a 6&nbsp;kV medium voltage cable network using the BPL (Broadband over Power Line) communication system. The tests are carried out under real mining conditions for the selected power cable without voltage, earthed at both sides. Such a method of monitoring work conditions is of great importance, especially during a disaster. Power cables are potentially resistant to mechanical damage and, thus, ensure continuity of transmission, also, in cases of electricity stoppage and partial damage (interruption) of the phase conductors. The voice transmission quality is tested for a relatively low bitrate of 8&nbsp;kbps–48&nbsp;kbps using both induction and mixed induction-capacitive coupling with the power cable. Such a solution should provide both reliable and high-quality services, considering clear and understandable voice messages to people. The quality evaluation is carried out on a group of 15 people aged between 25–35 years old. The tested signal samples consist of voice messages in British English, German, and Polish. On the basis of the investigated results, respective conclusions are formulated.</p> Grzegorz Debita Przemyslaw Falkowski-Gilski Marcin Habrych Bogdan Miedzinski Janusz Wandzio Przemyslaw Jedlikowski Copyright (c) 2019 Elektronika ir Elektrotechnika 2019-10-06 2019-10-06 25 5 43 46 10.5755/j01.eie.25.5.24355 Vehicle License Plate Detection and Perspective Rectification http://eejournal.ktu.lt/index.php/elt/article/view/24356 <p>The character segmentation and perspective rectification of Vehicle License Plate (VLP) is essential in different applications, including traffic monitoring, car parking, stolen vehicle recovery, and toll payment. The character segmentation of the VLP and its horizontal as well as vertical (pan and tilt) correction is a crucial operation. It has considerable impact on the precision of the vehicle identification process. In this work, we investigate an effective framework for the perspective rectification and homography correction of vehicle's images. The captured images of the vehicle could be tilted in vertical or horizontal or vertical-horizontal mix directions due to different movements. For reasonable high identification results, a polynomial fitting based homography correction method for rectifying the tilted VLPs is applied. A method for determining four corner points of the rotated VPLs is explored. These four detected corner points are applied in the homography correction algorithm. For comprehensively evaluating the performance of the proposed framework, the detected VLPs in various directions, such as horizontal, vertical, and mix horizontal-vertical, are rotated. For the experiments, the real images of the vehicles in the outdoor environment, from different directions and different distances are captured. With our proposed method, we achieve an accuracy of 97&nbsp;% and 95&nbsp;% for the simulated and real captured images, respectively.</p> Musaed Alhussein Khursheed Aurangzeb Syed Irtaza Haider Copyright (c) 2019 Elektronika ir Elektrotechnika 2019-10-06 2019-10-06 25 5 47 56 10.5755/j01.eie.25.5.24356 Adaptation of Full-Reference Image Quality Assessment Methods for Automatic Visual Evaluation of the Surface Quality of 3D Prints http://eejournal.ktu.lt/index.php/elt/article/view/24357 <p>Automatic visual quality assessment of the 3D printed surfaces is currently one of the most demanding challenges in additive manufacturing. Regardless of the applications of the computer vision for the 3D printing process monitoring purposes, a reliable surface quality evaluation during manufacturing may introduce brand new possibilities. The detection of some distortions and their automatic evaluation can be helpful when deciding to stop the process to save time, energy, and filament. In some cases, some further corrections can also be made for relatively small distortions. Since many general-purpose image quality assessment methods have been proposed in recent years, their applications for the quality evaluation in the additive manufacturing are investigated. As most of the metrics are full-reference and require the availability of the original perfect quality image, their direct application is not possible. Therefore, their adaptation is described in the paper together with experimental verification of classification results obtained using various metrics.</p> Krzysztof Okarma Jaroslaw Fastowicz Copyright (c) 2019 Elektronika ir Elektrotechnika 2019-10-06 2019-10-06 25 5 57 62 10.5755/j01.eie.25.5.24357 Subclass Separation of White Blood Cell Images Using Convolutional Neural Network Models http://eejournal.ktu.lt/index.php/elt/article/view/24358 <p>The white blood cells produced in the bone marrow and lymphoid tissue known as leucocytes are an important part of the immune system to protect the body against foreign invaders and infectious disease. These cells, which do not have color, have a few days or several weeks of life. A lot of clinic experience is required for a doctor to detect the amount of white blood cells in human blood and classify it. Thus, early and accurate diagnosis can be made in the formation of various disease types, including infection on the immune system, such as anemia and leukemia, while evaluating and determining the disease of a patient. The white blood cells can be separated into four subclasses, such as Eosinophil, Lymphocyte, Monocyte, and Neutrophil. This study focuses on the separation of the white blood cell images by the classification process using convolutional neural network models, which is a deep learning model. A deep learning network, which is slow in the training step due to the complex architecture, but fast in the test step, is used for the feature extraction instead of intricate methods. For the subclass separation of white blood cells, the experimental results show that the AlexNet architecture gives the correct recognition rate among the convolutional neural network architectures tested in the study. Various classifiers are performed on the features derived from the AlexNet architecture to evaluate the classification performance. The best performance in the classification of white blood cells is given by the quadratic discriminant analysis classifier with the accuracy of 97.78&nbsp;%.</p> Mesut Togacar Burhan Ergen Mehmet Emre Sertkaya Copyright (c) 2019 Elektronika ir Elektrotechnika 2019-10-06 2019-10-06 25 5 63 68 10.5755/j01.eie.25.5.24358 Outage and Bit Error Probability Analysis in Energy Harvesting Wireless Cooperative Networks http://eejournal.ktu.lt/index.php/elt/article/view/24359 <p>This study focuses on a wireless powered cooperative communication network (WPCCN), which includes a hybrid access point (HAP), a source and a relay. The considered source and relay are installed without embedded energy supply (EES), thus are dependent on energy harvested from signals from the HAP to power their cooperative information transmission (IT). Taking inspiration from this, the author group investigates into a harvest-then-cooperate (HTC) protocol, whereas the source and the relay first harvest the energy from the AP in a downlink (DL) and then collaboratively work in uplink (UL) for IT of the source. For careful evaluation of the system performance, derivations of the approximate closed-form expression of the outage probability (OP) and an average bit error probability (ABER) for the HTC protocol over Rayleigh fading channels are done. Lastly, the author group performs Monte-Carlo simulations to reassure the numerical results they obtained.</p> Ly Tran Thai Hoc Hoang-Sy Nguyen Quoc-Phu Ma Van Van Huynh Thanh-Long Nguyen Huynh Tan Phuoc Miroslav Voznak Copyright (c) 2019 Elektronika ir Elektrotechnika 2019-10-06 2019-10-06 25 5 69 74 10.5755/j01.eie.25.5.24359 Modelling VM Migration in a Fog Computing Environment http://eejournal.ktu.lt/index.php/elt/article/view/24360 <p>Fog Computing is created to efficiently store and access data without the limitations challenging Cloud Computing deployments, such as network latency or bandwidth constraints. This is achieved by performing most of the processing on servers located as close as possible to where data is being collected. When mobile devices are equipped with limited resources and small capabilities, it would be convenient to make their associated computing and network resources follow them as much as possible. In this paper, migration process is studied and an algorithmic model is designed, selecting a generic Fat Tree architecture as the underlying topology, which may be useful to get a list of all devices being traversed through each of the redundant paths available.</p> Pedro Juan Roig Salvador Alcaraz Katja Gilly Carlos Juiz Copyright (c) 2019 Elektronika ir Elektrotechnika 2019-10-06 2019-10-06 25 5 75 81 10.5755/j01.eie.25.5.24360 Development of Cyber-Physical Security Testbed Based on IEC 61850 Architecture http://eejournal.ktu.lt/index.php/elt/article/view/24361 <p>The paper focuses on security in industrial control systems. Numerous protocols and their incompatibility are undermining the security design. Also, the IEC 61850 standard focuses on these issues. In detail, it deals with the compatibility between protocols and, partly, security. In the context of this work, a testbed together with the traffic generator for IEC 61850 standard and its three main parts – MMS (Manufacturing Message Specification), GOOSE (Generic Object-Oriented Substation Events), and Sampled Values - are designed. Additionally, the used generator is compared with an example of RTU (Remote Terminal Unit) used in standard ICS (Industrial Control Systems) networks. The last part of this work consists of the performance testing of the implemented protocols (MMS, GOOSE, and Sampled Values).</p> Petr Blazek Radek Fujdiak Petr Mlynek Jiri Misurec Copyright (c) 2019 Elektronika ir Elektrotechnika 2019-10-06 2019-10-06 25 5 82 87 10.5755/j01.eie.25.5.24361 Reviewers http://eejournal.ktu.lt/index.php/elt/article/view/24362 Elektronika ir Elektrotechnika Copyright (c) 2019 Elektronika ir Elektrotechnika 2019-10-06 2019-10-06 25 5 89 89 10.5755/j01.eie.25.5.24362