Elektronika ir Elektrotechnika https://eejournal.ktu.lt/index.php/elt <div><em>ELEKTRONIKA IR ELEKTROTECHNIKA</em> (ISSN 1392-1215) is a peer-reviewed open access bimonthly research journal of Kaunas University of Technology.</div> <p>The research journal <em>ELEKTRONIKA IR ELEKTROTECHNIKA</em> publishes original research papers on featuring practical developments that might have a significant impact in the field of <em>electronics and electrical engineering</em>, and focuses on automation, robotics &amp; control; automotive electronics; electric vehicles; electrical engineering; electronic measurements; electronics; high frequency technologies, microwaves; micro &amp; nano-electronics; power electronics; renewable energy; signal technologies; telecommunications engineering. It is aimed not only to researchers of certain field , but also to the wider public.</p> <p><strong><em>WoS</em></strong><strong><em>: </em></strong><em>Impact</em> <em>Factor</em><em> 0.707 (</em><em>2019); </em><em>5-Year </em><em>Impact</em> <em>Factor</em> <em>0.656 (</em><em>2019) </em><strong><em>Scopus</em></strong><strong><em>:</em></strong> <em>SCImago</em> <em>Journal</em> <em>Rank</em><em> 0.18 (2019)</em></p> en-US <p>The copyright for the paper in this journal is retained by the author(s) with the first publication right granted to the journal. The authors agree to the <a href="https://creativecommons.org/licenses/by/4.0/" target="_blank" rel="noopener">Creative Commons Attribution 4.0 (CC BY 4.0)</a> agreement under which the paper in the Journal is licensed.</p> <p>By virtue of their appearance in this open access journal, papers are free to use with proper attribution in educational and other non-commercial settings with an acknowledgement of the initial publication in the journal.</p> eejournal@ktu.lt (Elektronika ir Elektrotechnika) eejournal@ktu.lt (Executive Editor Darius Andriukaitis) Wed, 24 Aug 2022 13:47:19 +0300 OJS 3.2.1.1 http://blogs.law.harvard.edu/tech/rss 60 Title https://eejournal.ktu.lt/index.php/elt/article/view/32130 Elektronika ir Elektrotechnika Copyright (c) 2022 Elektronika ir Elektrotechnika https://eejournal.ktu.lt/index.php/elt/article/view/32130 Wed, 24 Aug 2022 00:00:00 +0300 Mathematical Analysis and Design of a Novel 5-DOF 3D Printer Robotic System https://eejournal.ktu.lt/index.php/elt/article/view/31383 <p>In this study, the mathematical analysis and design of a new 3D printer with 5 degrees of freedom were carried out. Thanks to the developed system, a new concept has been brought to the multi-axis 3D printer mechanisms, and thus, it is aimed to improve the part quality in additive manufacturing (AM) processes. As a result of adding the 4<sup>th</sup> and 5<sup>th</sup> axes to the moving platform of the system, the production time of the part was accelerated. It is also possible to print more complex and curved shapes with less support. To design a system with these features, first of all, the kinematic analysis of the system was obtained using vector algebra, and the workspace of the current printer was determined by considering the system constraints in this article. By giving detailed information about the mechanical and electrical components of the designed system, the working principle of the whole system is presented. According to the findings obtained in the studies, the kinematic analyses performed for the proposed system proved to be correct and a new system was proposed especially for additive manufacturing technologies.</p> Ahmet Dumlu, Mehran Mahboubkhah, Kagan Koray Ayten, Gurkan Kalinay Copyright (c) 2022 Ahmet Dumlu, Mehran Mahboubkhah, Kagan Koray Ayten, Gurkan Kalinay https://eejournal.ktu.lt/index.php/elt/article/view/31383 Wed, 24 Aug 2022 00:00:00 +0300 Reinforcement Optimization Algorithm for Mobile Robot Sensor Networks Drive Motion Improvement https://eejournal.ktu.lt/index.php/elt/article/view/30736 <p>This paper proposed four optimization algorithms for mobile robot sensor networks that improve the kinematics drive motion in a reference map environment. The standard procedure followed in mobile robot sensor measurements considers a problem statement for relating the sensor measurements with a reference map. The initial path shows that the existing methods lack consideration of more sensor points without considering the boundary constraints and obstacles. The probabilistic path map can be rearranged according to the current location to improve the better drive motion, as well as to obey the fundamental kinematics equations. he obstacle crossing led to the development of new algorithms. Implementation of schemes is achieved in different map environments, and the accuracy of results outperforms conventional methods by 84.21 % to 96.94 %.</p> Suryaprakash Shanmugasundaram, Thirumoorthi Ponnusamy, Tamilarasu Viswanathan Copyright (c) 2022 Suryaprakash Shanmugasundaram, Thirumoorthi Ponnusamy, Tamilarasu Viswanathan https://eejournal.ktu.lt/index.php/elt/article/view/30736 Wed, 24 Aug 2022 00:00:00 +0300 Generalized Quasi-Orthogonal Functional Networks Applied in Parameter Sensitivity Analysis of Complex Dynamical Systems https://eejournal.ktu.lt/index.php/elt/article/view/31110 <p>This paper presents one possible application of generalized quasi-orthogonal functional networks in the sensitivity analysis of complex dynamical systems. First, a new type of first order (<em>k</em> = 1) generalized quasi-orthogonal polynomials of Legendre type via classical quasi-orthogonal polynomials was introduced. The short principle to design generalized quasi-orthogonal polynomials and filters was also shown. A generalized quasi-orthogonal functional network represents an extension of classical orthogonal functional networks and neural networks, which deal with general functional models. A sequence of the first order (<em>k</em> = 1) generalized quasi-orthogonal polynomials was used as a new basis in the proposed generalized quasi-orthogonal functional networks. The proposed method for determining the parameter sensitivity of complex dynamical systems is also given, and an example of a complex industrial system in the form of a tower crane was considered. The results obtained have been compared with different methods for parameter sensitivity analysis.</p> Sasa S. Nikolic, Dragan S. Antic, Nikola B. Dankovic, Aleksandra A. Milovanovic, Darko B. Mitic, Miroslav B. Milovanovic, Petar S. Djekic Copyright (c) 2022 Sasa S. Nikolic, Dragan S. Antic, Nikola B. Dankovic, Aleksandra A. Milovanovic, Darko B. Mitic, Miroslav B. Milovanovic, Petar S. Djekic https://eejournal.ktu.lt/index.php/elt/article/view/31110 Wed, 24 Aug 2022 00:00:00 +0300 Adaptive State Feedback Control Method Based on Recursive Least Squares https://eejournal.ktu.lt/index.php/elt/article/view/31149 <p>This study revealed an adaptive state feedback control method based on recursive least squares (RLS) that is introduced for a time-varying system to work with high efficiency. Firstly, a system identification block was created that gives the mathematical model of the time-varying system using the input/output data packets of the controller system. Thanks to this block, the system is constantly monitored to update the parameters of the system, which change over time. Linear quadratic regulator (LQR) is renewed according to these updated parameters, and self-adjustment of the system is provided according to the changed system parameters. The Matlab/Simulink state-space model of the variable loaded servo (VLS) system module was obtained for the simulation experiments in this study; then the system was controlled. Moreover, experiments were carried out on the servo control experimental equipment of the virtual simulation laboratories (VSIMLABS). The effectiveness of the proposed new method was observed taking the performance indexes as a reference to obtain the results of the practical application of the proposed method. Regarding the analysis of simulation and experimental results, the proposed approach minimizes the load effect and noise and the system works at high efficiency.</p> Mehmet Latif Levent, Omer Aydogdu Copyright (c) 2022 Mehmet Latif Levent, Omer Aydogdu https://eejournal.ktu.lt/index.php/elt/article/view/31149 Wed, 24 Aug 2022 00:00:00 +0300 Vehicle Make Detection Using the Transfer Learning Approach https://eejournal.ktu.lt/index.php/elt/article/view/31046 <p>Vehicle detection and classification is an important part of an intelligent transportation surveillance system. Although car detection is a trivial task for deep learning models, studies have shown that when vehicles are visible from different angles, more research is relevant for brand classification. Furthermore, each year, more than 30 new car models are released to the United States market alone, implying that the model needs to be updated with new classes, and the task becomes more complex over time. As a result, a transfer learning approach has been investigated that allows the retraining of a model with a small amount of data. This study proposes an efficient solution to develop an updatable local vehicle brand monitoring system. The proposed framework includes the dataset preparation, object detection, and a view-independent make classification model that has been tested using two efficient deep learning architectures, EfficientNetV2 and MobileNetV2. The model was trained on the dominant car brands in Lithuania and achieved 81.39 % accuracy in classifying 19 classes, using 400 to 500 images per class.</p> Dovile Komolovaite, Andrius Krisciunas, Ingrida Lagzdinyte-Budnike, Aurelijus Budnikas, Dominykas Rentelis Copyright (c) 2022 Dovile Komolovaite, Andrius Krisciunas, Ingrida Lagzdinyte-Budnike, Aurelijus Budnikas, Dominykas Rentelis https://eejournal.ktu.lt/index.php/elt/article/view/31046 Wed, 24 Aug 2022 00:00:00 +0300 Analysis of Public Agenda during Covid-19 Pandemics Based on Turkish and English Tweets Using Nonnegative Matrix Factorization and Hypothesis Testing https://eejournal.ktu.lt/index.php/elt/article/view/31196 <p>In this study, Turkish and English tweets through Twitter Application Program Interface (API) between 1-31 January 2021 are analyzed with respect to Covid-19. The collected tweets are preprocessed, labeled with the Vader Sentiment library, and then analyzed by topic modeling with Nonnegative Matrix Factorization. The analysis show that the most frequently mentioned word is “vaccine/aşı” after “Covid”. The topics modelled in the study are grouped into themes and the themes are seen to be similar in both languages, which means that the Turkish and world agenda are not very different in terms of themes in pandemics. Moreover, hypothesis tests are conducted to understand whether language and time period are related to sentiment class. The results show that the Turkish people are more neutral about the Covid-19 issue than other people in the world during the given period of time. Moreover, independent of the language, there are more negative and neutral tweets in the first half of January 2021, whereas there are more positive tweets in the second half of the month. To the best of our knowledge, this is the first study to analyze Covid-19 related tweets in two languages to compare the local and global agendas using topic modeling, sentiment analysis, and hypothesis testing methods.</p> Mustafa Yavas, Aysun Guran, Yeliz Ekinci Copyright (c) 2022 Mustafa Yavas, Aysun Guran, Yeliz Ekinci https://eejournal.ktu.lt/index.php/elt/article/view/31196 Wed, 24 Aug 2022 00:00:00 +0300 Editorial Board https://eejournal.ktu.lt/index.php/elt/article/view/32131 Elektronika ir Elektrotechnika Copyright (c) 2022 Elektronika ir Elektrotechnika https://eejournal.ktu.lt/index.php/elt/article/view/32131 Wed, 24 Aug 2022 00:00:00 +0300 Lithium-Iron-Phosphate Battery Performance Controlled by an Active BMS Based on the Battery-to-Cell Method https://eejournal.ktu.lt/index.php/elt/article/view/31420 <p>The article discusses the results of research on the efficiency of a battery assembled with lithium-iron-phosphate (LiFeP0<sub>4</sub>) cells when managed by an active Battery Management System (BMS) using the “battery-to-cell” energy transfer. This arrangement was especially developed by the authors and is intended for use in a selected suspended mining vehicle. The main emphasis was placed on variation of the two most important factors limiting in practice the effective use of a selected battery: a battery heating during operation and its voltage (power) fade over time. The advantage of the active BMS developed using the “battery-to-cell” energy transfer was compared both with the active BMS based on the cell-to-battery method and with the passive BMS as well. Particular attention was paid to the performance of the BMS balancing effect during the simulated unequal discharging of randomly selected cells (from 12 % to about 40 % of all cells number in the battery). The results obtained allowed for the formulation of appropriate conclusions and practical recommendations.</p> Wojciech Kurpiel, Bartosz Polnik, Piotr Hylla, Bogdan Miedzinski, Marcin Habrych, Grzegorz Debita Copyright (c) 2022 Wojciech Kurpiel, Bartosz Polnik, Piotr Hylla, Bogdan Miedzinski, Marcin Habrych, Grzegorz Debita https://eejournal.ktu.lt/index.php/elt/article/view/31420 Wed, 24 Aug 2022 00:00:00 +0300 Improvements of Organic Photodetectors for VLC Using a New Active Layer, Focal Lens, and a Transimpedance Amplifier https://eejournal.ktu.lt/index.php/elt/article/view/31292 <p>Beyond 5G networks, and for short distance but high-speed communication systems, there is an incipient growing interest in visible light communications (VLC). Furthermore, it is an interesting alternative within the framework of the Internet of Things (IoT). However, there is a problem on the part of the receiver in these systems, motivated by the non-existence of photovoltaic elements used particularly for this purpose. Because of their simplicity and small investment, organic-type photodetectors have a high capacity for use in VLC systems. With a structure of polymers represented by an organic photodetector fabricated with poly (3-hexylthiophene) (P3HT) and a bulk heterojunction active layer of phenyl-C61-butyric acid methyl ester (PCBM) and commercial LEDs, we show our system in this paper. The main novelty of this work is in reception. With different upgrade using a new active layer or adding a focal lens or inserting a transimpedance amplifier, we have achieved improved performance results related to voltage and distance, with an increase of more than 40 %, and Bit Error Rate (BER) by modifying the active layer concentration with respect to results obtained in a former work. Also, we have tested the use of a transimpedance amplifier to obtain the best results in distances of 12 cm to 20 cm and a focal lens with the same objective of improving the BER in critical environments, where the Signal-to-Noise Ratio (SNR) is close to zero. To conclude, these modifications show that it is possible to increase the main parameters of our system to be useful in VLC systems.</p> Pablo Corral, Fernando Rodriguez-Mas, Guillermo De Scals, David Valiente, Juan Carlos Ferrer, Susana Fernandez de Avila Copyright (c) 2022 Pablo Corral, Fernando Rodriguez-Mas, Guillermo De Scals, David Valiente, Juan Carlos Ferrer, Susana Fernandez de Avila https://eejournal.ktu.lt/index.php/elt/article/view/31292 Wed, 24 Aug 2022 00:00:00 +0300 Extraction of Cardiac Cell Membrane Fractional-Order Capacitance from Current Response to Voltage Step https://eejournal.ktu.lt/index.php/elt/article/view/31151 <p>The aim of the article is to examine the possibilities of modeling electrical properties of cardiac cell membrane using the Cole impedance model containing a fractional-order capacitor. A method is presented to determine the parameters of the model based on the current transient response to a voltage step applied to the membrane. The method is based on the numerical minimization of the least squares error between the recorded and calculated transient response of the model using the MATLAB function fminsearch. The use of a fractional-order capacitor in the membrane model is found to result in a reduction in the modeling error compared to that of the classic capacitor.</p> David Kubanek, Jaroslav Koton, Olga Svecova Copyright (c) 2022 David Kubanek, Jaroslav Koton, Olga Svecova https://eejournal.ktu.lt/index.php/elt/article/view/31151 Wed, 24 Aug 2022 00:00:00 +0300