Carpathian Journal of Electrical Engineering

Number 17, 2023

7-20
OPTIMAL PID CONTROLLER BASED ON AN IMPROVED SPARROW SEARCH ALGORITHM FOR MULTI-AREA FREQUENCY CONTROL

Authors: Amobi Edward OKOLO, Elvis TWUMASI, Emmanuel Asuming FRIMPONG

Abstract

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To boost power system reliability there must be a good scheme for the automatic generation control to maintain the generation-load balance. The development of this scheme started with the enhancement of the sparrow search algorithm, where the initial population and producer selection was targeted to improve the search quality. The enhancement made was used to optimize the gain parameters of the PID controller increasing the overall system performance. The proposed scheme was tested on the two-area power system in the MATLAB/Simulink environment and comparisons were made with recent publications. Integral time absolute error (ITAE) was used as the performance index. The proposed method shows improved performance with minimum settling time. This work presents the enhancement of the sparrow search algorithm for the automatic generation control of a two-area non-reheat thermal power system.

21-31
EXTENDED APPLIED DATA CLEANING METHODS IN OUTLIER DETECTION FOR RESIDENTIAL CONSUMER

Authors: Dacian I. JURJ, Dan D. MICU, Alexandru G. BERCIU, Mircea LANCRAJAN, Levente CZUMBIL, Andrei BENDE, Bogdan A. MITRACHE, Alexandru MUREȘAN

Abstract

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This paper delves into the subject of outlier detection techniques tailored for unique datasets related to residential energy consumption. Building upon the current state of research we introduce the Grubbs and Z-score methods and investigate a range of outlier detection strategies encompassing statistical, probabilistic, and machine learning algorithms. The findings underscore the importance of outlier detection in the Romanian residential energy sector.

32-41
ANALYSIS OF DIFFERENT DEEP LEARNING APPROACHES BASED ON DEEP NEURAL NETWORKS FOR PERSON RE-IDENTIFICATION

Authors: Adnan RAMAKIC, Zlatko BUNDALO, Dušanka BUNDALO

Abstract

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In this work, different deep learning approaches based on deep neural networks for person re-identification were analyzed. Both identification and re-identification of people are frequently required in various fields of human life. Some of the most common applications are in various security systems where it is necessary to identify and track a particular person. In the case of person identification, the identity of a particular person needs to be established. In the case of re-identification, the main task is to match the identity of a particular person across different, non-overlapping cameras or even with the same camera at different times. In this work, three different deep neural networks were used for the purpose of person re-identification. Two of them were user-defined, while one of them is a pre-trained neural network adapted to work with a specific dataset. Two neural networks used were Convolutional Neural Networks (CNN). For the defined experiment, it was used own dataset with 13 subjects in gait.

42-48
THE ELECTRICAL RESISTANCE OF THE LUBRICANT FILM IN THE CASE OF THE HYDRODYNAMIC SLIDING BEARING SUBJECTED TO SHOCKS

Authors: Ioan Marius ALEXANDRESCU, Radu COTETIU, Adriana COTETIU, Dinu DARABA, Ioana Laura ALEXANDRESCU

Abstract

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This paper presents experimental research on electrical resistance of the lubricant film, shock absorption in the lubricating film, under different static and dynamic load conditions. We focus on determination of the minimal lubricating film which estimates the minimum lubricating thickness between spindle and bushing in the case of the hydrodynamic sliding bearing subjected to shocks.

49-62
ALTERNATIVE LOW-COMPLEXITY APPROACHES FOR PAPR REDUCTION IN FBMC-OQAM SYSTEMS

Authors: Salima SENHADJI, Fethi Tarik BENDIMERAD

Abstract

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Recently, the Filter Bank Multi-Carrier with Offset-QAM modulation (FBMC-OQAM) system proved to be a strong candidate wave that can replace the conventional OFDM (Orthogonal Frequency Division Multiplexing) through several properties in future mobile generations (5G and 5G+). However, it faces a significant issue, which is high Peak-to-Average-Power-Ratio (PAPR) as all advanced waveforms. Many researchers have proposed either hybrid or non-hybrid techniques adapted to the FBMC-OQAM structure to minimize the PAPR parameter. Nevertheless, all of these techniques suffer from high complexity, which is a significant challenge in practical implementations. Therefore, in this paper, we propose two alternative low-complexity approaches, TD and TC, to effectively mitigate the PAPR problem in FBMC-OQAM systems. Both proposed hybrid schemes achieve superior PAPR performance compared to the conventional TR and very competitive results in comparison to the existing literature algorithms while requiring less computational complexity.

63-71
DECENTRALIZED ARCHITECTURES IN IOT DATA SHARING USING BLOCKCHAIN TECHNOLOGY

Authors: Cristinel COSTEA

Abstract

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The development of IoT applications generally relies on centralized architectures, whether they use solutions based on cloud or on premises environments, usually operated by a single entity. However, recent technologies and the increasing number of interconnected intelligent devices are driving new approaches, the essential requirements being scalability and fault-tolerance. This work studies an alternative concept based on a decentralized architecture useful in several scenarios and focuses on available technologies for potential practical implementations.

72-92
OPTIMIZING DUTY RATIOS IN A GRID-INTERACTIVE INVERTER: A FIVE-LEVEL, THREE-LEG, THREE-PHASE CASCADED H-BRIDGE APPROACH EMPLOYING MPCC WITH AN EXPLICIT INTEGRATION ALGORITHM

Authors: Edmund Kwafo ADJEI-SAFORO, Francis Boafo EFFAH, Misbawu ADAM, Ebrahimpanah SHAHROUZ,Emmanuel Asuming FRIMPONG

Abstract

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The model predictive current control stands out as a robust control strategy extensively applied in the enhancement of various industrial applications. Renowned for its capacity to handle multiple inputs and generate multiple outputs (MIMO), it is recognized for its consistently excellent performance and unique stable control techniques. However, the computational intensity required to remedy an optimization task at each time step poses a potential drawback, impacting its suitability for real-time control applications and potentially affecting system performance. This study introduces the concept of duty cycle optimization, leveraging the explicit integration approximation. This involves the application of rectangular voltage for both non-zero as well as zero within one control period to minimize current ripples in the grid-interactive system. Additionally, error minimization is achieved through the selection of the duration for the two-rectangular voltage. Experimental and simulation results validate the substantial reductions in ripple current as well as total harmonic distortion achieved through this approach.

93-99
STUDY ON THE EFFECTS OF MICROWAVES ON WATER HEATING AND THEIR INFLUENCE UPON THE GERMINATION PROCESS

Authors: Radu JOIAN, Dorin MANCIULA

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This paper considers an experimental study that considers the effects of heating water in a microwave oven. Thus, we wanted to check how harmful microwave-heated water is, and by extrapolation, how harmful microwave-heated food can be.

100-127
INVESTIGATING MAGNETIC CONTROLLED REACTOR PRINCIPLES AND CHARACTERISTICS UTILIZING ANSYS IN AN IN-DEPTH STUDY

Authors: Samuel Addo DARKO, Edmund Kwafo ADJEI-SAFORO, Misbawu ADAM, Solomon Nchor AKANSAKE

Abstract

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The inherent complexity leads to intricate equations, making it challenging for design engineers and researchers to model and analyze MCRs effectively. Despite the increasing attention given to MCRs in power systems, the need for simplified theoretical foundations and design models persists. This paper addresses the challenges posed by the complex excitation conditions of magnetic controlled reactors (MCRs), which are subject to both alternating current and direct current excitations by presenting the theoretical basis, ontological structure, working principle, and design model of MCRs in a systematic manner for enhanced comprehension. Graphical and equivalent electric circuit approaches are employed to derive mathematical expressions, while ANSYS simulation is utilized to create a 3D structure model of the MCR. The simulation results, compared with theoretical analyses, demonstrate that the MCR exhibits alternate magnetization and demagnetization between its two core limbs in a cycle. This suggests that the magnetic valves on both sides alternate between saturation and unsaturation in each cycle. Furthermore, the research reveals that the MCR’s entire capacity can be smoothly adjusted by varying the saturation degree of the magnetic valve core. Overall, this research contributes to a deeper understanding of MCRs under actual operating conditions and serves as a crucial foundation for further investigations into their performance design.

135-149
SIMULATION-BASED APPLICATION OF SAFETY OF THE INTENDED FUNCTIONALITY TO MITIGATE FORESEEABLE MISUSE IN AUTOMATED DRIVING SYSTEMS

Authors: Milin PATEL, Rolf JUNG

Abstract

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The development of Automated Driving Systems (ADS) has the potential to revolutionize the transportation industry, but it also presents significant safety challenges. One of the key challenges is ensuring that the ADS is safe in the event of Foreseeable Misuse (FM) by the human driver. To address this challenge, a case study on simulation-based testing to mitigate FM by the driver using the driving simulator is presented. FM by the human driver refers to potential driving scenarios where the driver misinterprets the intended functionality of ADS, leading to hazardous behavior. Safety of the Intended Functionality (SOTIF) focuses on ensuring the absence of unreasonable risk resulting from hazardous behaviors related to functional insufficiencies caused by FM and performance limitations of sensors and machine learning-based algorithms for ADS. The simulation-based application of SOTIF to mitigate FM in ADS entails determining potential misuse scenarios, conducting simulation-based testing, and evaluating the effectiveness of measures dedicated to preventing or mitigating FM. The major contribution includes defining (i) test requirements for performing simulation-based testing of a potential misuse scenario, (ii) evaluation criteria in accordance with SOTIF requirements for implementing measures dedicated to preventing or mitigating FM, and (iii) approach to evaluate the effectiveness of the measures dedicated to preventing or mitigating FM. In conclusion, an exemplary case study incorporating driver-vehicle interface and driver interactions with ADS forming the basis for understanding the factors and causes contributing to FM is investigated. Furthermore, the test procedure for evaluating the effectiveness of the measures dedicated to preventing or mitigating FM by the driver is developed in this work.

150-157
COMPUTER NETWORK SECURITY

Authors: Marijan MIJATOVIĆ, Marko MIJATOVIĆ

Abstract

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Computers that we connect to a network serve to exchange data, which is located in the computer’s working memory. Data transmission can also be done through electronic signals, and these connections can be wireless networks or wired networks. The bits that are sent one after another simultaneously correspond at an appropriate speed, converting digital signals into analog signals and vice versa, which is a modern process. Computers can also be connected to a local network and a branched network. Each computer connected to the network has its own unique number (address) from which it can be recognized on which continent it is, in which country, and to which server address it is connected. Data is sent according to a pre-agreed protocol, in the form of packets. Security measures for protecting sensitive data and documents have existed for a long time in the world. Throughout history, many methods have been developed regarding data protection and internet security. Methods of providing protection on the internet were sometimes not effective and did not provide the necessary level of protection. With the development of cryptography and technology, very good methods of encryption and document protection have been discovered. Information systems are the foundation of basic and modern business operations. Their fundamental task is to be based on network systems, as well as their operation and security. That’s why it’s extremely important to familiarize ourselves with the security issues of computer networks and the ways in which these problems are resolved.

158-171
WATERFALL OR SCRUM METHODOLOGY – HOW TO CHOOSE ACCORDING TO THE SPECIFIC PROJECT?

Authors: Mirko SAJIĆ1, Saša ČEKRLIJA, Mladen BUBONJIĆ, Goran KALINIĆ, Radmila BOJANIĆ, Slađana BABIĆ

Abstract

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This paper aims to perform a comparison of two methodologies used in project management and project work. It first describes the basic characteristics, strengths, and weaknesses of both methodologies to facilitate reaching certain conclusions. Then, it derives specific conclusions through a cross-comparison.