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Öğe A Novel Approach for Channel Allocation In OFDM Based Cognitive Radio Technology(Springer, 2021) Yılmazel, Rüstem; İnanç, NihatWhen the number of users in the radio environment is increasing and the rapid development in the wireless environment is examined, the efficient use of the spectrum decreases gradually. Cognitive radio technology as one of the spectrum sensing techniques for 5G (Fifth Generation) and beyond communication systems has been studied in recent years to prevent spectrum inefficiency. According to different researches, spectrum usage is not always the same by the licensed user. Certain parts of the spectrum is used very little or inefficient. OFDM-based cognitive radio technology developed to increase spectum efficiency has enabled the use of empty channels. In this article, a new approach is proposed by combining artificial intelligence techniques and spectrum detection algorithms. The accuracy of the results was observed by applying this new technique to OFDM technology. Genetic algorithm (GA) is used to make the best field channel allocation and highest accuracy for the use of the spectrum. It was found that the optimized result with the help of genetic algorithm was better than the results without using genetic algorithm. As a result of the study, the accuracy of the channel allocation has increased significantly with the new approach proposed. In this article, it is possible to integrate different spectrum allocation techniques for secondary users by using artificial intelligence. The requirements of the system are given as input data and accordingly the probability of detection is examined. Thanks to this method, empty frequencies are continuously scanned and correct channel allocation is ensured. The results obtained in this article show that both the channel assignment is correct and the primary user is detected without any problems.Öğe Channel Optimization By Using Spectrum Sensing Techniques In Cognitive Radio Network(2020) Yılmazel, Rüstem; İnanç, NihatIn recent years, the rapid development of wireless technologies has increased the need for frequency spectrum usage. To overcome this problem, Cognitive Radio (CR) has emerged as a new technique which enables the use of free ranges in the frequency spectrum. Cognitive radio networks (CRNs) are based on the principle of benefiting from the empty spectrum of secondary users (Sus) by using sensing techniques and analyzing frequency ranges. Although the frequency spectrum is used by various technologies, some frequency ranges are used inefficiently and inadequately. Fixed spectrum allocations cause unused frequency channels in the radio frequency spectrum. Spectrum detection, which is one of the features that cognitive radio applies to reduce the inefficiency of spectrum usage, scans all the primary users (PUs) in the spectrum area and the empty frequency bands. In this study, a method has been proposed to detect unused stationary frequency bands and to use these frequency bands effectively. This method, which is named as matched filter detection , was examined in AWGN channel and its results were evaluated in MATLAB.Öğe Channel Optimization By Using Spectrum Sensing Techniques In Cognitive Radio Network(Kırıkkale Üniversitesi, 2020) Yilmazel, Rustem; İnanç, NihatIn recent years, the rapid development of wireless technologies has increased the need for frequency spectrum usage. To overcome this problem, Cognitive Radio (CR) has emerged as a new technique which enables the use of free ranges in the frequency spectrum. Cognitive radio networks (CRNs) are based on the principle of benefiting from the empty spectrum of secondary users (Sus) by using sensing techniques and analyzing frequency ranges. Although the frequency spectrum is used by various technologies, some frequency ranges are used inefficiently and inadequately. Fixed spectrum allocations cause unused frequency channels in the radio frequency spectrum. Spectrum detection, which is one of the features that cognitive radio applies to reduce the inefficiency of spectrum usage, scans all the primary users (PUs) in the spectrum area and the empty frequency bands. In this study, a method has been proposed to detect unused stationary frequency bands and to use these frequency bands effectively. This method, which is named as matched filter detection , was examined in AWGN channel and its results were evaluated in MATLAB.Öğe Control of mobile robot formations using A-star algorithm and artificial potential fields(National Research and Innovation Agency (BRIN), 2021) Manuel, Nelson Luis; İnanç, Nihat; Erten, Mustafa YasinFormations or groups of robots become essential in cases where a single robot is insufficient to satisfy a given task. With an increasingly automated world, studies on various topics related to robotics have been carried out in both the industrial and academic arenas. In this paper, the control of the formation of differential mobile robots based on the leader-follower approach is presented. The leader's movement is based on the least cost path obtained by the A-star algorithm, thus ensuring a safe and shortest possible route for the leader. Follower robots track the leader's position in real time. Based on this information and the desired distance and angle values, the leader robot is followed. To ensure that the followers do not collide with each other and with the obstacles in the environment, a controller based on artificial potential fields is designed. Stability analysis using Lyapunov theory is performed on the linearized model of the system. To verify the implemented technique, a simulator was designed using the MATLAB programming language. Seven experiments are conducted under different conditions to show the performance of the approach. The distance and orientation errors are less than 0.1 meters and 0.1 radians, respectively. Overall, mobile robots are able to reach the goal position and maintaining the desired formation in finite time. © 2021 Research Centre for Electrical Power and Mechatronics - Indonesian Institute of Sciences.Öğe Hybrid Speed Controller Design Based on Sliding Mode Controller Performance Study for Vector Controlled Induction Motor Drives(Taiwan Association of Engineering and Technology Innovation, 2021) Nurettin, Abdülhamit; İnanç, NihatThe discontinuous control of the sliding mode control (SMC) law causes chattering phenomenon in system trajectories (the oscillation around the desired value), which results in various unwanted effects such as current harmonics and torque ripples. Therefore, this study aims to investigate the performance of a sliding mode speed controller for a three-phase induction motor (IM) controlled by a rotor flux orientation technique to obtain optimum performance. The study results show that the experimental control gains found in the control law have a clear effect on limiting chattering and the system response speed. According to the study results, a hybrid controller is designed based on the fuzzy logic control (FLC) approach to optimally tune these gains. The designed hybrid controller is verified by experimental approximation of simulations using Matlab/Simulink. The simulation results show that the hybrid controller reduces the chattering phenomenon and improves the system’s dynamic performance. © by the authors. Licensee TAETI, Taiwan.Öğe The impact of disabling suspicious node communications on network lifetime in wireless ad hoc sensor networks(Tubitak Scientific & Technical Research Council Turkey, 2016) Pala, Zeydin; İnanç, NihatIn wireless sensor networks (WSNs), the data observed by different nodes must be relayed safely to the base station over intermediate nodes. In the network environment, some sensor nodes can act suspiciously when they enter someone else's control or due to other equipment failure. Data packets that are sent through suspicious nodes may be randomly dropped or may be not delivered as desired. In this paper, we investigate the impact of disabling suspicious nodes communications on network lifetime through a linear programming framework. We build a mathematical programming framework and perform comprehensive numerical analysis. Our results show that the decrease in WSN lifetime is less than 8.0% if the number of suspicious nodes is not higher than 10%.Öğe IoT based Smart Home Testbed using MQTT Communication Protocol(2020) Yalçınkaya, Fikret; Aydilek, Hüseyin; Erten, Mustafa Yasin; İnanç, NihatTechnology is developing day by day in the world. In addition, developing technologies bring innovations and conveniences to all areas of life. However, ensuring the continuity of these innovations brought by technology reveals different problems. Smart home approach, which increases the quality of human living areas, is one of the most popular working subjects of recent times. In a smart home, built with the Internet of Things technology products, it is very important that the sensors and control devices communicate in a safer way and work in a coordinated manner to ensure the ecosystem's continuity in a safer way. In this study, an IoT based smart home testbed was realized by using MQTT communication protocol which one of the most used IoT communication protocols. With the developed system, the control of the smart home and the operating performance of the system were controlled with the mobile application. The results obtained in the light of the data provided by the test show that the system developed with the MQTT communication protocol can successfully ensure data flow and control in Smart Home applications.Öğe IoT based Smart Home Testbed using MQTT Communication Protocol(Kırıkkale Üniversitesi, 2020) Yalçınkaya, Fikret; Aydilek, Hüseyin; Erten, Mustafa Yasin; İnanç, NihatTechnology is developing day by day in the world. In addition, developing technologies bring innovations and conveniences to all areas of life. However, ensuring the continuity of these innovations brought by technology reveals different problems. Smart home approach, which increases the quality of human living areas, is one of the most popular working subjects of recent times. In a smart home, built with the Internet of Things technology products, it is very important that the sensors and control devices communicate in a safer way and work in a coordinated manner to ensure the ecosystem's continuity in a safer way. In this study, an IoT based smart home testbed was realized by using MQTT communication protocol which one of the most used IoT communication protocols. With the developed system, the control of the smart home and the operating performance of the system were controlled with the mobile application. The results obtained in the light of the data provided by the test show that the system developed with the MQTT communication protocol can successfully ensure data flow and control in Smart Home applications.Öğe Optimal Site Selection for a Solar Power Plant in the Central Anatolian Region of Turkey(Hindawi Ltd, 2017) Akkas, Özge Pınar; Erten, Mustafa Yasin; Çam, Ertuğrul; İnanç, NihatPrimary energy sources are running out due to the increase in electrical energy consumption. Environmental problems caused by primary energy sources are also increasing. Using more renewable energy resources (RES) can be considered as one of the most powerful solutions to address these problems. Today, required photovoltaic power systems (PVPS) and wind energy systems (WES) are widely used as RES for addressing these problems. Because of their high costs, feasibility studies are required for locating large systems associated with these resources. In this study, various suggestions are determined about location selection, which is an important stage in the PVPS's establishment. Hence, the criteria for selecting the appropriate location are analyzed by the multicriteria decision making (MCDM) methods and the results are evaluated for 5 cities in the Central Anatolian Region of Turkey. In conclusion, it is determined which city is the most suitable place for installation of solar power plants.Öğe Recognition of Daily and Sports Activities(Ieee, 2018) İnanç, Nihat; Kayri, Murat; Ertuğrul, Ömer FarukSince being physically inactive was reported as one of the major risk factor of mortality, classifying daily and sports activities becomes a critical task that may improve human life quality. In this paper, the daily and sports activities dataset was used in order to evaluate and validate the employed approach. In this approach, the statistical features were extracted from the histograms of the local changes in the wearable sensors logs were obtained by one-dimensional local binary patterns. Later, extracted features were classified by extreme learning machines. Results were showed that the proposed approach is enough to recognize the action type, but in order to recognize the actions, or gender, different feature extraction methods must be employed.Öğe Sensorless Vector Control for Induction Motor Drive at Very Low and Zero Speeds Based on an Adaptive-Gain Super-Twisting Sliding Mode Observer(IEEE-Inst Electrical Electronics Engineers Inc, 2023) Nurettin, Abdulhamit; İnanç, NihatTo achieve a balance between estimation accuracy and the chattering problem for sensorless induction motor IM drive systems at very low and zero speeds, an adaptive-gain super-twisting sliding mode observer (AGSTSMO) is proposed. The value of the adaptive gains (experimental observer coefficients) in the control law is assigned utilizing Lyapunov stability theory to ensure expeditious convergence of the estimated variables to improve the accuracy and suppress chattering at very low and zero speeds operation. The AGSTSMO eliminates the need to use a low-pass filter to obtain the equivalent control, as in the traditional first-order sliding-mode observer, which causes a delay in estimating the equivalent control law. Simulation and experimental results are shown under different operating conditions to illustrate the effectiveness of the suggested approach, which achieves excellent estimation precision and chattering elimination capability simultaneously, thus increasing robustness versus deviations of the motor parameters. Moreover, to prove the superiority and efficiency of the proposed observer is compared to that of a super-twisting sliding mode observer (STSMO) under various operating conditions.Öğe Signal and Noise Subspace Decomposition for a Linear Antenna Array Using SVD(Ieee, 2018) Aytaş, Nilay; Afacan, Erkan; İnanç, NihatIn the vast majority of signal processing applications, the signal is intended to be analyzed to obtain a variety of data from the signal. It is decomposed into signal subspaces to perform this analysis. The noise in the signal during analysis is undesirable. If the signal incoming to an antenna array contains noise, it should be filtered before processing signal. In this study, we have tried to divide the uniform linear antenna array into subspaces of incoming signals from multiple signal sources with various frequencies, noise and arrival angles. The Singular Value Decomposition (SVD) method is used to separate the signal subspace and noise subspace. According to the singular values obtained, the information about the frequencies of the signals and whether the signal contains noise. Also, the number of sources can be estimated by means of singular values.Öğe Sliding Mode Control-Based MPPT and Output Voltage Regulation of a Stand-alone PV System(Sciendo, 2022) Manuel, Nelson Luis; İnanç, NihatWhen it comes to reducing emissions caused by the generation of electricity, among different renewable energy sources, the solar energy gains prominence, due to its geographical availability, simplicity of implementation, and absence of physical moving parts. However, the performance of photovoltaic systems is dependent on environmental conditions. Depending on temperature and solar irradiation, the photovoltaic (PV) system has an operating point where maximum power can be generated. The techniques that are implemented to find this operating point are the so-called maximum power point tracking (MPPT) algorithms. Since weather conditions are variable in nature, the output voltage of the PV system needs to be regulated to remain equal to the reference. Most of the existing studies focus either on MPPT or on voltage regulation of the PV system. In this paper, the two-stage PV system is implemented so that both MPPT and voltage regulation are achieved simultaneously. Additionally, an improved version of the perturb and observe (P&O) algorithm based on artificial potential fields (APF), called APF-P&O, is presented. According to the results of the simulations carried out in MATLAB/Simulink software, the APF-P&O method is more efficient than the conventional method.Öğe The Application of Matrix Pencil Method for Direction Finding Using a Linear Antenna Array(IEEE, 2021) Aytaş, Nilay; Afacan, Erkan; İnanç, NihatThe estimation of the direction of signal sources is used especially in military applications such as radar systems, locating systems, military warfare systems, and in civil applications such as mobile communication systems. The systems that used to only determine the location of a single signal source have obtained the ability to simultaneously detect the direction and location of signals from multiple signal sources following the development of subspace techniques. Matrix Pencil method is a method used in subspace analysis of the signal, in this study, it is aimed to estimate the direction of arrival of the signals impinging from one or more signal sources to the antenna array using this method. The analysis showed that high accuracy results have been obtained in the estimation of the direction of arrival the signals impinging to the antenna array by Matrix Pencil method.
