Elektronika ir Elektrotechnika 2020-06-29T14:38:31+03:00 Elektronika ir Elektrotechnika Open Journal Systems <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The research journal ELEKTRONIKA IR ELEKTROTECHNIKA publishes previously unpublished manuscripts that will have a high impact in the field of electronics and electrical engineering.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> Title 2020-06-29T13:29:54+03:00 Elektronika ir Elektrotechnika 2020-06-26T15:36:26+03:00 Copyright (c) 2020 Elektronika ir Elektrotechnika Editorial Board 2020-06-29T13:29:55+03:00 Elektronika ir Elektrotechnika 2020-06-26T15:38:55+03:00 Copyright (c) 2020 Elektronika ir Elektrotechnika Fuzzy Expert System for Earthquake Prediction in Western Himalayan Range 2020-06-29T14:38:31+03:00 Rabia Tehseen Muhammad Shoaib Farooq Adnan Abid <p>Fuzzy Expert System (FES) with application to earthquake prediction has been presented to reproduce the performance of a human expert in earthquake prediction using expert systems. This research aims to predict future earthquakes having a magnitude 5.5 or greater. Previous earthquake data from 2000 to 2019 have been collected for this purpose. Since the earthquake data for the specified region have been reported on different magnitude scales, suitable relationships were determined to obtain uniform data. The uniform data have been used to calculate seismicity indicators according to the guidelines provided by Gutenberg-Richter’s scale for quantitative determination of earthquake features. The relationships among these seismic indicators have been used by the human expert to set the rule base of Fuzzy expert system. These rules have been mathematically validated and tested on instrumentally recorded earthquake data. The results obtained from the proposed FES presented 47&nbsp;% accuracy in predicting future earthquakes that may occur in the 100&nbsp;km radial area from 34.708&nbsp;° N, 72.5478&nbsp;° E.</p> 2020-06-26T15:31:02+03:00 Copyright (c) 2020 Elektronika ir Elektrotechnika Subjective and Objective Quality Evaluation Study of BPL-PLC Wired Medium 2020-06-29T14:38:31+03:00 Grzegorz Debita Przemyslaw Falkowski-Gilski Marcin Habrych Bogdan Miedzinski Bartosz Polnik Jan Wandzio Przemyslaw Jedlikowski <p>This paper presents results of research on the effectiveness of bi-directional voice transmission in a 6&nbsp;kV mine cable network using BPL-PLC (Broadband over Power Line - Power Line Communication) technology. It concerns both emergency cable state (supply outage with cable shorted at both ends) and loaded with distorted current waveforms. The narrowband (0.5&nbsp;MHz–15&nbsp;MHz) and broadband (two different modes, frequency range of 3&nbsp;MHz–7.5&nbsp;MHz) transmission efficiency, considered as an objective study, was correlated with the level of noise in the cable for both induction-inductive and mixed capacitive-inductive coupling of the measurement devices and/or modems. The quality of voice transmission, considered as a subjective study, was assessed by a group of 15 people aged between 25 and 35 years old. The test audio signals included samples in 3 languages sourced from ITU (International Telecommunication Union) and processed in 3 bitrates ranging from 8&nbsp;kbps to 24&nbsp;kbps.</p> 2020-06-26T00:00:00+03:00 Copyright (c) 2020 Elektronika ir Elektrotechnika FFT-Based Data Hiding on Audio in LWT-Domain Using Spread Spectrum Technique 2020-06-29T14:38:31+03:00 Gelar Budiman Andriyan Bayu Suksmono Donny Danudirdjo <p>Audio watermarking is a process to hide digital data without being seen or heard by the sense of sight or hearing. Watermaking is applied to insert the copyright on digital media, such as an image file, an audio file or a video file. In this paper, we propose watermarking procedure to embed spread spectrum watermark into frequency domain of adaptive selected subband from host audio. Lifting Wavelet Transform (LWT) is used to decompose the host audio into several subbands, and then Fast Fourier Transform (FFT) transforms selected several subbands with lowest energy. The watermark image is converted into one-dimensional signal, then it is modulated by imperceptible pseudo-noise (PN) code with controlled gain. Next, the frequency domain of audio is added by modulated and imperceptible watermark prior to transforming it to time domain by Inverse FFT (IFFT) obtaining watermarked subbands. Finally, the watermarked subbands are combined with other unused subbands by inverse LWT (ILWT) becoming the perfect version of watermarked audio. The result of this method has good robustness against most attacks from stirmark benchmark experiments, good imperceptibility with Signal to Noise Ratio (SNR) more than 30&nbsp;dB and payload 172.66&nbsp;bps.</p> 2020-06-26T16:36:34+03:00 Copyright (c) 2020 Elektronika ir Elektrotechnika Combining DVR and UPS Techniques for an Uninterruptable Supply of Ultra-Sensitive Non-Linear Appliances 2020-06-29T14:38:31+03:00 Branislav Dobrucky Jozef Sedo Roman Konarik <p>The paper deals with an application of combined techniques of dynamical voltage restorer (DVR) and uninterruptible power supply (UPS) that make possible both the short voltage sags compensation, as well as longer power supply interruptions, under the simultaneous operation of equipment and network. This is enabled mainly by an instantaneous voltage sag detection, quick bidirectional over-switches, and an instantaneous control method of the output voltage. This needs a fast control method, which can provide a voltage recovery for phase-sensitive loads during several calculation steps, so the dead-beat regulator is used. Such a system even compensates for the influence of non-linear loads on the power supply network without a change of a phase and amplitude of the supply voltage. The simulation results in Matlab/Simulink, as well as real experiments and their comparison results, are given in the paper.</p> 2020-06-26T17:02:48+03:00 Copyright (c) 2020 Elektronika ir Elektrotechnika Dual-Mode Multifunctional Reconnection-Less Reconfigurable Filter 2020-06-29T14:38:31+03:00 Lukas Langhammer Roman Sotner Jan Dvorak Tomas Dostal <p>A novel solution of a reconnection-less reconfigurable filter is being presented. The filter works in the current mode, voltage mode, and mixed mode (voltage tocurrent) offering sixteen transfer functions in total. The structure utilizes a voltage differencing transconductance amplifier, current follower and voltage, and current amplifiers. The designed structure offers the control of the pole frequency and quality factor and the adjustment of the band-stop/band-pass area of available functions. The proposed design is supported by the PSpice simulations using available simulation models.</p> 2020-06-26T17:39:40+03:00 Copyright (c) 2020 Elektronika ir Elektrotechnika Hardware Acceleration of Sparse Support Vector Machines for Edge Computing 2020-06-29T14:38:30+03:00 Vuk Vranjkovic Rastislav Struharik <p>In this paper, a hardware accelerator for sparse support vector machines (SVM) is proposed. We believe that the proposed accelerator is the first accelerator of this kind. The accelerator is designed for use in field programmable gate arrays (FPGA) systems. Additionally, a novel algorithm for the pruning of SVM models is developed. The pruned SVM model has a smaller memory footprint and can be processed faster compared to dense SVM models. In the systems with memory throughput, compute or power constraints, such as edge computing, this can be a big advantage. The experiments on several standard datasets are conducted, which aim is to compare the efficiency of the proposed architecture and the developed algorithm to the existing solutions. The results of the experiments reveal that the proposed hardware architecture and SVM pruning algorithm has superior characteristics in comparison to the previous work in the field. A memory reduction from 3 % to 85 % is achieved, with a speed-up in a range from 1.17 to 7.92.</p> 2020-06-27T08:33:27+03:00 Copyright (c) 2020 Elektronika ir Elektrotechnika Small Motion Detection and Non-Contact Vital Signs Monitoring with Continuous Wave Doppler Radars 2020-06-29T14:38:30+03:00 Ibrahim Seflek Yunus Emre Acar Ercan Yaldiz <p>Radars have become devices that one can come across in any environment at any moment. This means that they enter to all areas of life and even in the field of medicine and will be used more intensively in the future. Especially, the attention has been drawn to that they are suitable for the non-contact vital signs monitoring. In this study, two radar structures operating at 24 GHz (Radar 1) and 2.4 GHz (Radar 2) frequencies are used. Radar 1 structure is created on a printed circuit board (PCB), whereas Radar 2 is obtained by combining discrete components. The 8.5 mm movement performed with the aid of a test mechanism is detected by two radars with percentage errors (PEs) of 2.58% and 6.23%, respectively. For the 0.25 Hz vibration frequency, the error is the same for both radars and is 2.4 %. In measurements taken from a healthy human subject, Radar 1 finds a respiration rate with 1.85 % of PE and heart beat rate with 6.17 % of PE. In Radar 2, these values are 2.35 % and 8.24 %, respectively. From the measurement results, it is seen that the resolution of Radar 1 is better than that of Radar 2. The results also indicate that small motion detection and vital signs monitoring are carried out successfully.</p> 2020-06-27T09:10:46+03:00 Copyright (c) 2020 Elektronika ir Elektrotechnika Evaluation of Wind Energy Accommodation Based on Two-Stage Robust Optimization 2020-06-29T14:38:30+03:00 Kunpeng Tian Weiqing Sun Dong Han Ce Yang <p>Large-scale renewable energy integration brings unprecedented challenges to electric power system planning and operation. The paper aims at economic dispatch and the safe operation of high penetration renewable energy power systems. According to the principle of power system dispatchability, the assessment of wind energy accommodation is formulated into a two-stage robust optimization problem with a min-max-min structure. Based on the benders algorithm, the intractable robust optimization problem is transformed into the form of sub-problem and master problem. Strong duality theory and big-M method are used to recast the sub problem into a mixed integer linear programming. The envelope of wind energy accommodation can be obtained by using commercial software to solve the master problem and sub problem alternately. For the realization of arbitrary wind power within the envelope, the amount of wind energy leakage and load shedding in power system operation are acceptable. An example of modified IEEE 39-bus test systems is used to verify the effectiveness and practicability of the evaluation method.</p> 2020-06-27T09:29:59+03:00 Copyright (c) 2020 Elektronika ir Elektrotechnika Single Conversion Stage Three Port High Gain Converter for PV Integration with DC Microgrid 2020-06-29T14:38:30+03:00 Muhammad Arif Mohsin Shahzad Jawad Saleem Waheed Malik Abdul Majid <p>A high gain three port converter with a unidirectional port for photovoltaic (PV) side and two bidirectional ports one each for the battery and the DC bus for PV integration to DC microgrid is presented. High gain is achieved by a coupled inductor with switched capacitor, whereas single stage conversion is used between the ports to achieve high efficiency. The proposed converter is modelled in PLECS/MATLAB and the simulated results for various operational modes are validated using a 500 W prototype. For main operating mode, i.e., single input single output (SISO), the efficiency is calculated to be as high as 96 %. Similarly, owing to the reduced number of components, the losses are reduced considerably for different operation modes.</p> 2020-06-27T09:51:18+03:00 Copyright (c) 2020 Elektronika ir Elektrotechnika Swarm Decomposition Technique Based Hybrid Model for Very Short-Term Solar PV Power Generation Forecast 2020-06-29T14:38:30+03:00 Emrah Dokur <p>Accurate predictions of solar photovoltaic (PV) power generation at different time horizons are essential for reliable operation of energy management systems. The output power of a PV power plant is dependent on non-linear and intermittent environmental factors, such as solar irradiance, wind speed, relative humidity, etc. Intermittency and randomness of solar PV power effect precision of estimation. To address the challenge, this paper presents a Swarm Decomposition Technique (SWD) based hybrid model as a novel approach for very short-term (15 min) solar PV power generation forecast. The original contribution of the study is to investigate use of SWD for solar data forecast. The solar PV power generation data with hourly resolution obtained from the field (grid connected, 857.08 kWp Akgul Solar PV Power Plant in Turkey) are used to develop and validate the forecast model. Specifically, the analysis showed that the hybrid model with SWD technique provides highly accurate predictions in cloudy periods.</p> 2020-06-27T00:00:00+03:00 Copyright (c) 2020 Elektronika ir Elektrotechnika Reviewers 2020-06-29T13:29:58+03:00 Elektronika ir Elektrotechnika 2020-06-27T00:00:00+03:00 Copyright (c) 2020 Elektronika ir Elektrotechnika