Yazar "Kabalci, Yasin" seçeneğine göre listele
Listeleniyor 1 - 20 / 73
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe 5G Mobile Communication Systems: Fundamentals, Challenges, and Key Technologies(Springer, 2019) Kabalci, YasinWireless and mobile communication technologies exhibit remarkable changes in every decade. The necessity of these changes is based on the changing user demands and innovations offered by the emerging technologies. This chapter provides information on the current situation of fifth generation (5G) mobile communication systems. Before discussing the details of the 5G networks, the evolution of mobile communication systems is considered from first generation to fourth generation systems. The advantages and weaknesses of each generation are explained comparatively. Later, technical infrastructure developments of the 5G communication systems have been evaluated in the context of system requirements and new experiences of users such as 4K video streaming, tactile Internet, and augmented reality. After the main goals and requirements of the 5G networks are described, the planned targets to be provided in real applications by this new generation systems are clarified. In addition, different usage scenarios and minimum requirements for the ITU-2020 are evaluated. On the other hand, there are several challenges to be overcome for achieving the intended purpose of 5G communication systems. These challenges and potential solutions for them are described in the proceeding subsections of the chapter. Furthermore, massive multiple-input multiple-output (MIMO), millimeter wave (mmWave), mmWave massive MIMO, and beamforming techniques are clarified in a detail which are taken into account as promising key technologies for the 5G networks. Besides, potential application areas and application examples of the 5G communication systems are covered at the end of this chapter. © Springer Nature Singapore Pte Ltd 2019.Öğe A Differential Search Algorithm Application for Solving Harmonic Estimation Problems(IEEE, 2017) Kabalci, Yasin; Kockanat, Serdar; Kabalci, ErsanThis paper presents an optimization approach based differential search algorithm (DSA) for amplitude and phase estimation of time varying power signal in electrical power systems. Proposed method has been tested for two well-known literature problems that include fundamental, sub-and inter-harmonic estimation cases. The performance of the suggested DSA method has been compared with those of the Genetic Algorithm-Least Square (GA-LS), Particle swarm optimization with passive congregation least square (PSOPC-LS), Bacterial foraging optimization (BFO), Fuzzy bacterial foraging-least square (F-BFO-LS) and Bacterial foraging optimization-recursive least square (BFO-RLS). The results show that the proposed DSA method has an efficient, fast and accurate estimation behavior among previously reported ones in the case of time varying harmonic power signals. In addition, the estimated amplitude and phase values using DSA method can provide possibility to design suitable harmonic reducing filter for improving power quality.Öğe A framework for Gaussian Q approximation with BSA and its application to RIS-assisted systems(Elsevier Gmbh, 2024) Bilim, Mehmet; Kabalci, YasinThis paper proposes a novel and improved Chiani approximation for the Gaussian Q-function by employing the backtracking search optimization algorithm (BSA). The proposed approximation includes only exponential terms which are comfortable for the mathematical functionality. Then, a wireless communication application of reconfigurable intelligent surface (RIS) structures, which are anticipated to play a crucial role in integrated sensing and communication (ISAC), has been presented. In the considered wireless communication scenario, the link between the source and RIS node is Nakagami-m fading, while the link between RIS node and the destination is Rayleigh fading. The received probability density function (PDF) expression of instantaneous signal to noise ratio for this system has been derived analytically. Using this derived PDF, the error expression (Pe) for the RISassisted communication system employing the rectangular quadrature amplitude modulation (RQAM) technique has been obtained with the assistance of the proposed improved Chiani approximation in this study. The obtained RQAM error figures are presented comparatively, and the results clearly show that the Pe expression by obtained the proposed approximation with BSA for the RIS-assisted communication system, which is an important aspect for ISAC, is in excellent agreement with computer simulations.Öğe A Low Cost Smart Metering System Design for Smart Grid Applications(IEEE, 2016) Kabalci, Yasin; Kabalci, ErsanThe most important parts of the smart meters are the sensing devices that are utilized to measure for both current and voltage magnitudes of the systems. Therefore, several investigations have to be carried out to improve practical applications of the smart metering systems. This paper presents a novel sensing device design for AC measurement systems. The proposed sensing system is firstly designed by means of the computer simulation tools and then the printed circuit board of the designed metering system is implemented. Afterwards, the practical circuit is tested under different conditions. In addition, the proposed system is compared with the previously designed sensing circuit by authors in terms of cost, advantages and disadvantages. The obtained results emphasized that the proposed new sensing circuit is capable of very low cost and very high accuracy.Öğe A modelling case study of an island mode solar power plant(Institute of Electrical and Electronics Engineers Inc., 2015) Kabalci, Ersan; Gorgun, Alper; Kabalci, Yasin; Gokkus, GokselThe solar panel model is designed according to equation of a solar cell, and all the required parameters such as open circuit voltage, short circuit current etc are considered in order to modify the output power regarding to a commercial photovoltaic (PV) panel. The dc-dc conversion is performed with a buck converter where the optimal duty cycle is dynamically updated by a proportional-integral (PI) controlled generator. The settling time and dc voltage ripples are minimized to increase the efficiency of the dc-dc converter. On the other hand, the single-phase inverter is constructed with an H-bridge that is the most basic multilevel topology known ever. The main intention during the inverter operation was decreasing the total harmonic distortion (THD) ratios as much as possible. Therefore, the modulation scheme is particularly applied to decrease THD by eliminating side band harmonics. The line voltage is properly fixed to 220V/50Hz that is common in northern and central Europe. The THD ratio of the line voltage is measured at 0.03%, while the THD of the current is 0.82%. The power factor of the entire system is measured as 0.99 considering the 8.1° phase displacement between current and voltage waveforms. The analysis results verify the efficiency of the proposed solar power plant and its components.; This paper deals with efficiency analysis of a solar power plant that is considered to be installed in island mode with 2 kWp rated power. The test bed designed in Simulink © 2015 IEEE.Öğe A Modelling Case Study of an Island Mode Solar Power Plant(IEEE, 2015) Kabalci, Ersan; Kabalci, Yasin; Gorgun, Alper; Gokkus, GokselThis paper deals with efficiency analysis of a solar power plant that is considered to be installed in island mode with 2 kWp rated power. The test bed designed in Simulink c consists of solar panel, buck converter, and H-bridge inverter models all based to analytical concepts. The solar panel model is designed according to equation of a solar cell, and all the required parameters such as open circuit voltage, short circuit current etc are considered in order to modify the output power regarding to a commercial photovoltaic (PV) panel. The dc-dc conversion is performed with a buck converter where the optimal duty cycle is dynamically updated by a proportional-integral (PI) controlled generator. The settling time and dc voltage ripples are minimized to increase the efficiency of the dc-dc converter. On the other hand, the single-phase inverter is constructed with an H-bridge that is the most basic multilevel topology known ever. The main intention during the inverter operation was decreasing the total harmonic distortion (THD) ratios as much as possible. Therefore, the modulation scheme is particularly applied to decrease THD by eliminating side band harmonics. The line voltage is properly fixed to 220V/50Hz that is common in northern and central Europe. The THD ratio of the line voltage is measured at 0.03%, while the THD of the current is 0.82%. The power factor of the entire system is measured as 0.99 considering the 8.1 phase displacement between current and voltage waveforms. The analysis results verify the efficiency of the proposed solar power plant and its components.Öğe A New Approach Based on Differential Evolution Algorithm for Harmonic Estimation Problems(IEEE, 2017) Kockanat, Serdar; Kabalci, Yasin; Kabalci, ErsanElectrical harmonic is an important issue affecting power quality of electrical systems. Estimation of power harmonics are essential to design filters to be utilized in electrical power systems for reducing harmonics and their effects on the electrical power systems. In this study, a harmonic estimator based on differential evolution algorithm is proposed for harmonic estimation problems shown in power systems. Analyses of designed estimator are performed for two different experiments. In addition, performances of proposed estimator are compared with available results of the literature. The achieved results of this study showed that the proposed harmonic estimator in this paper is superior among previously reported ones.Öğe A Single-Axis Solar Tracking System and Monitoring Software(IEEE, 2015) Kabalci, Ersan; Calpbinici, Ayberk; Kabalci, YasinIn this paper, the application of a portable solar tracking system is implemented to increase energy generation of the photovoltaic (PV) panels. While this portable system provides the monitoring of the maximum solar radiation values, the creation of more efficient solar tracking system is also another significant contribution. Thus, a system which continuously records and monitors the generated voltage, solar irradiation value and the panel position is proposed. The voltage, actual panel direction and irradiation data is continuously read by the improved control circuit and transmitted via Radio Frequency (RF) communication to the data collection card connected to the computer. The data received by the data acquisition cards is sent to the computer via Universal Serial Bus (USB) communication protocol. These data are monitored through the interface coded in computer and also recorded in the database. Thus, the retrospective irradiation and voltage information obtained by monitoring system performance can be monitored by the proposed system.Öğe A survey on smart metering and smart grid communication(PERGAMON-ELSEVIER SCIENCE LTD, 2016) Kabalci, YasinThe smart metering and communication methods used in smart grid are being extensively studied owing to widespread applications of smart grid. Although the monitoring and control processes are widely used in industrial systems, the energy management requirements at both service supplier and consumer side for individuals promoted the evolution of smart grid. In this paper, it is aimed to disclose in a clear and clean way that what smart grid is and what kind of communication methods are used. All components of a smart grid are introduced in a logical way to facilitate the understanding, and communication methods are presented regarding to their improvements, advantages, and lacking feature. The developing generation, transmission, distribution and customer appliances are surveyed in terms of smart grid integration. The communication technologies are introduced as wireline and wireless classification where the key features are also tabulated. The security requirements of hardware and software in a smart grid are presented according to their cyber and physical structures. (C) 2015 Elsevier Ltd. All rights reserved.Öğe A wireless metering and monitoring system for solar string inverters(Elsevier Sci Ltd, 2018) Kabalci, Ersan; Kabalci, YasinThe design and implementation studies of a real time monitoring and smart metering system are presented in this study. The proposed design is improved in terms of smart metering infrastructure based on current, voltage, and power measurements. The communication among the string inverter and host PC is performed by the designed ZigBee transceiver system. Sensing circuits are the most significant devices for measuring both current and voltage magnitudes of the systems. The measured data are processed by the microcontroller unit (MCU) and are modulated after signal processing operations for serial communication. Although the transceiver is configured to execute bi-directional communication, unidirectional data flow is performed where the smart metering system transmits data to monitoring substructure. The monitoring software is also implemented in the context of the presented study. The Visual Studio software development kit is used to design and to code the software by using C#. The performed experimental studies showed that the proposed real time monitoring and smart metering system could be exploited to monitor current, voltage and power magnitudes of the string inverters in an efficient way.Öğe An improved approximation for the Nakagami-m inverse CDF using artificial bee colony optimization(Springer, 2018) Kabalci, YasinThe quantile function [or inverse cumulative distribution function (CDF)] is a probabilistic measure that is widely employed in both statistical applications and Monte Carlo methods. In addition, this function is important to determine performances of the communication systems, especially for wireless communication systems. However, numerical computing of the Nakagami-m inverse CDF is quite difficult because of the fact that a closed-form expression of the Nakagami-m inverse CDF is not available. In this paper, an improved expression for the Nakagami-m inverse CDF is presented by using curve-fitting methods. Furthermore, parameters of the proposed mathematical model are optimized by the help of artificial bee colony algorithm that is a population based meta-heuristic optimization method motivated by the foraging behavior of honey bee swarms. The results acquired by the proposed approximation are also compared with other existing approaches in the literature in terms of complexity and performance. It is shown that the presented approximation is more accurate, simple and effective against to the previously reported approximations.Öğe An Overview of Big Data Concepts, Methods, and Analytics: Challenges, Issues, and Opportunities(IEEE, 2023) Mahmoudian, Mahshad; Zanjani, S. Mohammadali; Shahinzadeh, Hossein; Kabalci, Yasin; Kabalci, Ersan; Ebrahimi, FarshadIn recent years, data generation is increasing on a large scale and fast pace, and the development of Internet applications, mobile applications, and network-connected sensors has also increased widely. These applications and extensive internet connections continuously produce a large volume of data, with a wide diversity and different structures, which is called big data. At the same time, technologies related to big data are also developing. The rapid growth of cloud computing and the Internet of Things (IoT) is accelerating the dramatic growth of data generation. Sensors around the world are collecting and transmitting data that will be stored and processed in the cloud, and the era of big data is coming. In this article, first, an overview of big data and the definitions of its features are explained, and then the applications of big data in different fields are examined and the challenges facing it are discussed. Finally, technologies related to big data in the field of big data analysis, data storage technologies, and visualization tools are proposed and cloud computing, IoT, and data center are examined as new technologies that are closely related to big data. The main goal of this article is to provide a comprehensive overview of big data and examine and explain various aspects of its applications and implementation.Öğe Approximate Error Probability Analysis of L-Branch MRC System over ?-? Fading Environments(IEEE, 2024) Mutlu, Ural; Bilim, Mehmet; Kabalci, YasinThe increase in research conducted on next-generation communication systems has directed research interest toward new modulation schemes, channel models, and diversity techniques that promise enhanced efficiency. Recently, new analytical channel models capable of better modeling the wireless communication environment have been developed. In this study, the approximate error performance of hexagonal quadrature amplitude modulation (HQAM) in lambda - mu fading channels for multi-branch single-input multiple-output (SIMO) systems is investigated. An analytical expression for the error probability of the considered system is derived using the Prony approximation for the Gaussian Q function. Subsequently, an error probability expression for the considered system is proposed. Comparative results between the approximate results obtained from the derived expression and the exact simulation results are presented. Different scenarios are evaluated to analyze the effects of channel fading parameters, the number of transmission branches, and modulation levels, resulting in numerical outcomes. Ultimately, it was observed that the approximate results obtained from the proposed expression closely matched the exact simulation results, confirming the accuracy of the proposed analytical expression.Öğe Artificial bee colony optimization for modelling of indoor PLC channels: A case study from Turkey(ELSEVIER SCIENCE SA, 2015) Develi, Ibrahim; Kabalci, Yasin; Basturk, AlperIn this study, a channel model which is based on practical channel measurements obtained from electrical networks in Turkey is proposed for power line communication (PLC) systems. Experimental measurements are realized in different cities and various indoor places such as laboratory, university office and apartment house in order to achieve a general and appropriate PLC channel model for different locations and environments. Acquired data from the electric grid are stored on a database and PLC channel modelling process is carried out depending on these data through curve fitting methods. Moreover, parameters of the derived mathematical model are optimized by using artificial bee colony algorithm. Results show that the PLC channel model proposed in this study can be utilized to simulate PLC systems and to perform conformance tests of prototypes. (C) 2015 Elsevier B.V. All rights reserved.Öğe Centralized power generation(Elsevier, 2020) Kabalci, Ersan; Boyar, Aydın; Kabalci, YasinThe power generation has been centralized for many years. The conventional power network comprises large hydropower plants (HPPs), thermoelectric power plants, and nuclear power plants. This chapter deals with the central generation and the most common power plants being used all over the world. It is aimed to provide further understanding of power generation and central generation plants in terms of their physical, mechanical, and electrical configurations. The HPPs have been represented according to architectural structures, hydraulic turbines, types of generators used for electromechanical conversion and power generation. Afterward, the thermoelectric plants have been discussed in terms of fuel types and operation principles that are the second major generation plants in many countries. The nuclear power plants that are being discussed and criticized for many years have also dealt in terms of their power generation structures and current situation in the world. The chapter is expected to provide a base before the representation of distributed generation and renewable energy sources in the following chapters. © 2021 Elsevier Inc. All rights reserved.Öğe Channel Estimation In Intelligent Reflecting Surfaces for 5G and Beyond(IEEE, 2022) Mutlu, Ural; Kabalci, YasinIntelligent Reflecting Surfaces (IRS) are constructed of multiple independently controllable passive Reflecting Elements (RE), which can change the phase and amplitude of the reflected signals so that the reflected signals can be combined in coherent manner to achieve beamforming. To facilitate beamforming, the channel coefficients of the incoming and outgoing channels need to be estimated. In this study, the Discrete Fourier Transform (DFT) based channel estimation method is applied to an IRS-assisted communication system implementing Fifth Generation (5G) Orthogonal Frequency Division Multiplexing (OFDM) waveform in order to observe the effectiveness of the estimation method. DFT-based channel estimation has the advantage of not using the whole OFDM symbol for pilot transmission, thus it can be performed while transmitting data. Therefore, the effects of multipath delay spread, the number of REs, and training sequence sparsity in the OFDM symbol are observed for different Signal-to-Noise Ratio (SNR) values with a direct path and without a direct path. The results show that delay spread has a significant effect on the performance and training sequence length can be reduced.Öğe Channel Estimation in RIS-aided Multi-User OFDM Communication Systems(IEEE, 2024) Mutlu, Ural; Kabalci, Yasin; Cengiz, AlperenReconfigurable Intelligent Surfaces (RIS) are planar arrays constructed of independently controllable passive reflecting elements that change the phase and the amplitude of the reflected signals between Base Station (BS) and User Equipment (UE). To facilitate the coherent combination of the reflected signals, the Channel State Information (CSI) of the channels should be known by the communication network. The main issue with CSI estimation in unstructured channels is the high number of channels and the long training time that is required to apply orthogonal training reflection patterns at the RIS. With multiple users, the required training period becomes even longer. Therefore, this study proposes allocating the users with orthogonal pilot sequences, which are transmitted over the orthogonal frequency division multiplexing (OFDM) frequency domain with the aim of separating the user signals in the frequency domain. In the study, the cascaded channels are separated in the time domain by a reflection pattern consisting of a DFT matrix and the users are separated in the frequency domain by the use of the Hadamard matrix. The algorithms are simulated over a 3GPP-defined Tapped Delay Line (TDL) channel model as well as a Rayleigh fading channel. The results show that due to the use of orthogonal sequences, channel estimation improves in flat fading channels, while the performance is also of acceptable level in frequency selective channels.Öğe Communication Methods for Smart Buildings and Nearly Zero-Energy Buildings(Springer International Publishing Ag, 2017) Kabalci, YasinThis chapter presents wired and wireless communication systems in smart homes and smart buildings by considering the recent developments seen in applications. In order to provide further knowledge for readers, the basic principles of the smart homes and energy efficient buildings are firstly introduced. Then, the nearly zero-energy buildings and renewable energy integration in buildings issues are comprehensively explained by taking into account existing applications. In addition, advanced metering infrastructure that is a vital component of the smart home systems is expressed in detail. Afterwards, the potential candidates of communication systems for smart buildings that have an important role to realize nearly zero-energy buildings are discussed by comparing each method and application types thoroughly. These communication systems are classified as wired and wireless communication systems to examine more detailed and the communication systems are compared according to several considerable parameters such as used spectrum, modulation types, bit rates, supported network topologies, media access control (MAC) schemes, carrier types, and application areas. Moreover, several applications of examined communication systems are presented both for outdoor and indoor scenarios.Öğe Comparison of Model Predictive Torque Control Based NPC and ANPC Inverters for IM Drive(IEEE, 2023) Kabalci, Ersan; Kabalci, Yasin; Boyar, AydinAn induction motor (IM), which is one of the ac electric motors, is commonly preferred in industrial applications. The IM has a simple structure, low maintenance, and is inexpensive. Inverter topologies are widely used in IM drives. Studies on the IM drive with multilevel inverter topologies, which have benefits such as higher efficiency, lower harmonic ratio, and reduced filter size are increasing day by day compared to two-level inverter topologies. In this study, various analyzes of a neutral point clamped (NPC) inverter and an active neutral point clamped (ANPC) inverter topologies for model predictive torque control (MPTC) based IM drive have been carried out under the same conditions. Firstly, the proposed IM drives have been modeled with MATLAB/Simulink, and then, their implementations have been carried out. The modeling and implementation analyses validate the effectiveness of the proposed MPTC-based IM drives in terms of flux and torque responses, as well as speed control. They have been deeply analyzed under variable load and speed conditions, and compared in terms of efficiency and total harmonic distortion (THD).Öğe Deep Learning Aided Channel Estimation Approach for 5G Communication Systems(IEEE, 2022) Mutlu, Ural; Kabalci, YasinThe defining feature of the Fifth Generation (5G) mobile communication systems is going to be Multiple Input Multiple Output (MIMO) transmission scheme, which utilizes the multipath diversities to achieve beamforming and increase spectral efficiency. However, these MIMO algorithms rely on accurate channel parameters. To improve the accuracy of the channel coefficients, the study presents a Deep Learning (DL) based approach that uses the 5G Demodulation Reference Signals (DMRS) as training sequence and Deep Neural Networks (DNN) as training and prediction network in a MIMO scenario. The DNN is trained with training data obtained by applying Least Squares (LS) method to the received pilot signals and by comparing it to Clustered Delay Line (CDL) channel model. The DNN is then used to predict real-time channel coefficients. The results show that the model improves channel estimation performance by reducing the effects of noise, thus improving the Normalized Mean Square Error (NMSE) versus Signal-to-Noise Ratio (SNR) metric of the MIMO system.
