Theses supervised by Prof. Dr. Halil Tanyer Eyyuboğlu
15 theses · Çankırı Karatekin Üniversitesi, Çankaya University
PV solar generation and technologies, comparison of MONO-SI, POLY-SI and thin-film panels
Renewable energy is energy derived from natural sources that is replenished at a rate that exceeds what is consumed. Renewable energy sources are abundant, and they are all around us. In contrast, fossil fuels (including gas, oil, and coal) are exhausted over time and require millions of years to create from scratch. Climate change and the increase in fossil fuel prices in the wake of the global increase in energy demand have prompted research to focus on the development of alternative resources. One of the most promising options seems to be solar energy, which can be converted directly into electricity thanks to the PV effect. Solar energy allows for decentralized energy production, which adapts to both resources and local needs and offers significant energy autonomy. A better, more sustainable, and more reliable electrical supply may be achieved by decentralized power generation using renewable energy sources. Solar modules differ in production technology, quality, method of use, and many other parameters. In this project, solar energy, solar modules, and their components will be introduced, and solar cell parameters will be determined. These types will then be compared in terms of efficiency and losses.
Sayısal haberleşme sistemlerinde kullanılan modülasyon tekniklerinin MATLAB ve FPGA kullanılarak gerçekleştirilmesi ve zedboard'a aktarılması
Bu araştırmanın amacı 5G ortamında sayısal modülasyon tekniklerinden PSK (Faz Kaydırmalı Anahtarlama), QPSK (Dört Evreli Faz Kaydırmalı Anahtarlama) ve OFDM (Dik Frekans Bölmeli Çoğullama) Modülünün MATLAB HDL Coder yardımıyla gerçekleştirmek ve Zynq-7000 Zedboard'ına aktararak gerçek ortamda haberleşme projelerine destek vermektir. Projenin ilk aşamasında MATLAB ta PSK sembolleri oluşturulup bir M-ary seviye sinyal ile QPSK sembolleri oluşturulmuştur. Ardından HDL kod üreteci kullanılarak oluşturulanlar VHDL e çevrilmiştir. Son olarak oluşturulan bit dosyası FPGA kartına yüklenmiş ve doğrulaması yapılmıştır. Projenin son kısımlarında QPSK modülasyonundan OFDM Modülüne geçiş yapılmıştır. OFDM'in 5G'deki kullanımı göz önüne alındığında, projenin yerli üretim ve araştırma potansiyeline önemli katkılar yapacağı düşünülmektedir. Öte yandan hazırlanan düzeneğin yeni nesil şebekelerde kullanılacak modülasyon türlerini de araştırmak için iyi bir ortam sağlayacağı öngörülmektedir.
Çok kriterli karar verme yöntemi ile enerji nakil hatlarının önceliklendirilmesi
Son yıllarda nüfus artışları ile birlikte elektrik enerjisi ihtiyacı artmaktadır. Elektrik enerjisi konforlu bir yaşam standardı sunmasının ardında çok önemli mühendislik hesapları gerektirdiği açık bir gerçektir. Bu nedenle elektriğin üretiminden son tüketiciye kadar yatırım planlamasının tüm kriterler göz önüne alınarak titizlikle hazırlanması gerekmektedir. Enerji Nakil Hatları (ENH) üretilen enerjinin dağıtım merkezleri arasında taşınmasını sağlamaktadır. ENH projelerinin daha kısa zamanda daha az hatayla yapılması, dolaylı olarak ülke ekonomisine katkı sağlaması açısından büyük önem taşımaktadır. Dağıtım şirketlerinde bütçe dahilinde ENH'ların seçiminde planlamacının seçimi yanlı fikirlere neden olur. Bu durum planlamacının bilgi birikimi ile sınırlı kalır. Birçok seçeneğin bulunduğu bu durumlarda karar verme sorunu karmaşık bir problemdir. ENH'ların önceliklendirilmesinde; Tedarik sürekliliğini arttırmaya yönelik yatırımlar, Yasal yatırımlar ve ARGE yatırımları başlığı altında pek çok kriterler göz önüne alınmalıdır. Bu çalışmada, yıllık bütçe dahilinde tesis edilmesi planlanan ENH'larının Çok Kriterli Karar Verme (ÇKKV) yöntemlerinden öncelikle Analitik Hiyerarşi Prosesi (AHP) yöntemi kullanılarak kriterlerin ağırlıkları hesaplanıp, İdeal Çözüme Yakınlığa Göre Tercih Sıralama Tekniği Yöntemi (TOPSIS) ile seçeneklerin sıralanması/değerlendirilmesi yapılmıştır. Değer verileri üç örnek uygulama üzerinde gerçekleştirilmiştir.
Design and investigation of next generation access network based on advanced optical carrier generator
Passive Optical Network (PON) was designed in this thesis. The design aim was to locate faulty line of service professionally without extra effort. In the literature, there were various PON-design methodologies. However, a design with less components and less faulty line tracking was a challenge. The suggested approach tried to overcome the leakage in the state-of-the-art, such that, the PON network would be able to serve forty-eight Optical Network Units (ONUs). At the same time, the design has to have the capability to distinguish the dropped line of service straightforwardly. The design in this thesis mainly depends on the Fiber Bragg Gratings (FBGs) to create six-groups, in each group, there are eight-branches. Each branch serves as an end-user/customer point. The capacity of fault location was achieved for ONUs distanced/located as far as 20Km from the Central Office (CO). There was only one Optical Spectrum Analyser (OSA) inside the CO. This OSA employed to monitor the whole network groups, i.e., forty-eight branches/ONU were screened inside the CO to predict the fault location. The system is built using the OptiSystem software package version 14.
Signal detection in OFDM systems for visible light communication based on deep learning
In this thesis, for signal detection in orthogonal frequency division multiplexing systems, the deep learning neural network is utilize to classify symbols at the receiver. The symbol error rate and least square and minimum mean square error estimations are compare after the long short-term memory based neural network has been train for a single subcarrier. This initial trial's offline training and online deployment stages are anticipate using a fixed wireless channel. Each transmitted orthogonal frequency division multiplexing packet has a random phase shift performed to assess the neural network's stability
Comparison of probability of error performance for truncated Bessel and Bessel Gauss beams
In this thesis, probability of error and SNR performances of truncated Bessel and Bessel-Gauss beams in free space optical communication system were compared. Source beams were determined as truncated Bessel and Bessel-Gauss beam. Then, the simulation of propagation of these beams was simulated in MATLAB. This simulation was performed by using random phase screen approach. Random phase screen was used as a model of the turbulent atmosphere in reality. Data symbols were transmitted to receiver side through the random phase screen. To reach the probability of error of this communication system, error counting was applied. By this way, performance comparison of the beams was derived and relative plots were located in this paper.
BER and SNR performance analysis of 2-ASK & 4-ASK modulated truncated bessel beams on different receiver apertures in FSO communications links
In this thesis, varying turbulent atmosphere environment are simulated random phase screen method. 2-ASK & 4-ASK modulated truncated Bessel beam are generated and propagated through turbulent atmosphere utilizing random phase screens. In MATLAB environment error counting method is applied then simulation results are obtained corresponding to BER and SNR. On the other hand, the contributions of enlargement receiver aperture on BER is examined. Also, to comprehend the free space optical (FSO) communication architecture in detail and to support the future experimental studies, FSO communication transmitter and receiver systems are designed.
New designs of microwave fractal resonators for modern wireless applications
In this dissertation, new microstrip bandpass and bandstop filters based on fractal resonators have been presented in an attempt to construct filter designs with smaller size for almost modern wireless applications. The proposed bandpass filter structures have been generated based on Moore, Hilbert, Hilbert-zz and Sierpinski fractal geometries while the proposed bandstop filter is based on Hilbert Fractal resonators. The space-filling property and the self-similarity of the configurations related to the consecutive iteration levels of these fractal geometries have been found to create compact filter structures with accepted performance results. Narrowband compact Moore fractal filters from 2nd and 3rd iteration levels have been designed for 2.4 GHz band application using a relative dielectric constant of 10.8 and dielectric thickness of 1.27 mm with good performance results in their quasi elliptic responses. For 3rd iteration Moore bandpass filter, size reduction percentage as compared with 2nd iteration one resonating at the same frequency and using the same substrate material for 3rd iteration structure is 43% .The simulated and measured results are well-matched to each other . Stepped impedance Hilbert microstrip bandpass filters have designed with characteristics of compacted sizes and narrow band responses which are the requisites of recent wireless communication systems. These filters are built from two edge coupled resonators, each resonator has been achieved by applying step impedance resonator generator on 1st and 2nd iterations of Hilbert fractal resonators on each segment for each fractal iteration . They have been proposed for the ISM band applications at center frequency of 2.4 GHz using a substrate with a dielectric coefficient of 9.6 and thickness of 0.508 mm. Results show that these filters own satisfactory output frequency responses. Size reduction percentage as compared with 1st iteration stepped impedance Hilbert bandpass filter operating at similar frequency and using similar substrate material for 2nd iteration structure is 63.34% . New fractal design scheme based on Hilbert-zz curve has been used to produce compact microstrip bandpass filter .This fractal filter has been realized using two coupled resonators using additional coupling stubs .The material substrate has relative dielectric constant of 9 and thickness of 1.27 mm. Simulation graphs demonstrate that these filters possess good transmission and return loss features for the resultant frequency responses. It should be mentioned that Moore, stepped impedance Hilbert resonator and Hilbert-zz bandpass filters exhibit higher harmonics eliminations in out of passband regions of their frequency responses which are much desired properties in modern wireless communications. Miniaturized microstrip bandpass filters have been designed using Sierpinski fractal curves from 0th to 3rd iteration levels. The intended filter designs have been performed using dual-mode square slotted microstrip resonator in accordance with adopted fractal iterations. These microstrip bandpass filters have less bandwidth and sharper transmission responses than those of the single mode resonator and traditional square patch filter. Filter structures generating from the successive iterations of the applied fractal geometries exhibit a noticeably low insertion loss, and sharper response of about 1% fractional bandwidth as compared with the conventional microstrip square patch filter of 3% fractional bandwidth constructed at the same resonant frequency of 5.33 GHz and using substrate material of dielectric coefficient of 10.8 and thickness of 1.27 mm. A new dual-band microstrip bandpass filter has been designed using Peano fractal geometry at resonant frequencies of 2.25 GHz and 4.825 GHz using a substrate of a relative dielectric constant of 10.8 and thickness of 1.27 mm. The topology of this filter consists of dual edge coupled resonators constructed from 1st iteration of Peano fractal geometry. Simulated responses show that this filter has well frequency responses as well as dual bands gained which are highly requested in current communication systems. On the other hand, new designs of Wide Bandpass Filter (WBPF) and Narrow Bandstop Filter (NBSF) based on Hilbert fractal resonators have been investigated using Sonnet simulator. The frequency responses properties of the proposed filters have been studied to observe the corresponding broad bandpass and narrow bandstop behaviours at the frequency around 2GHz.Moreover, the phase dispersion and surface current density details about proposed filters have been presented and analyzed. The proposed fractal filters have been found to possess compact sizes with flexible designs in addition to good frequency responses. The modeling, simulation and performance evaluation have been performed using the method of moment (MoM) package Microwave Office 2009 from Advanced Wave Research (AWR) and a full-wave based electromagnetic simulator Sonnet software package which are very commonly used in electronics industry and research institutions.
Comparison of beam profiles from analytic solution and computational models
In this thesis, we have compared the receiver plane beam profiles by computing the Huygens-Fresnel integral as convolution integral and Fourier integral operator and the results obtained from analytic derivation. The comparisons made on different beam types such as Gaussian, Annular-Gaussian, Sine-Gaussian, Sinh-Gaussian, Cos-Gaussian, Cosh-Gaussian beams. To make computations and comparisons we have developed a Matlab code, this code formulates the field expression for beam types on source plane, computes the receiver plane intensity distribution for three approaches of Huygens-Fresnel diffraction integral, and compares the results. Using this code, for the mentioned beam types, receiver beam profiles are computed and compared against different propagation distances and different beam parameters in free space.
OFDM transmitter and receiver implementation on FPGA
In this thesis, digital modulations which are 4QAM and QPSK are designed and implemented using FPGA hardware using OFDM communication technique. The Genesys Virtex-5 development card produced by Digilent is used as hardware. The development of the relevant card software was developed with the System Generator Blocks and native Simulink blocks in Simulink (MATLAB 2012a) and transferred to the corresponding card. In the steps of developing algorithms, digital modulation techniques are used.
Spectral analysis of ECG signals for pre-diagnosis of heart diseases
In this thesis we used the three cases for diagnosis of the heart attacks. The first case is healthy persons, second case is non healthy persons and the last one is unknown persons. For detection of them we used the correlation and auto correlation between the cases. For the simulation results we used the MATLAB programming languages. For diagnosis we used two statistical method. The first one is to take only one dice (assuming that this selected dice is a perfect representative of the remaining dice) and throw it many times (multiplying the time axis, to get time average). The second is to throw all dice or some of the dice at the same time (multiplying the event axis, to get ensemble average). The question is how many times should the experiment be repeated along time axis in the first case and how many dice thrown at a time in the second case so that we arrive at a result well approximated to the ones to get a result within 98 % confidence interval the minimum number that an experiment should be performed
Scintillation and bit error rate performance comparison of bottle and sine hollow beams
This thesis involves scintillation behavior, and probability of error estimation of optical wireless communication links using bottle and sine hollow beams on the source plane. In addition to performance over communication link, propagation and kurtosis parameter of bottle beams are analyzed as well. Analytical derivation of scintillation of bottle beam is performed utilizing Rytov scintillation theory. Since equations becomes too complicated to solve intensity profiles, kurtosis parameter, scintillation estimation, and probability of error values of selected bottle beams are obtained benefiting from random phase screen approach. Utilizing the same method, scintillation index and bit error rate(BER) of sine hollow beam are evaluated too. Our results show that asymmetric bottle beams have less scintillation value under the same conditions as compared to corresponding symmetric ones. This brings us, asymmetric bottle beams have less bit error rate when signal to noise ratio is constant. Since, scintillation index of sine hollow beam becomes less than Gaussian beam in weak turbulence, this beam seems advantageous considering BER for weak turbulence. Scintillation results are compared with spherical wave and obtained probability of error values are compared with the analytical formula and plotted in this study.
The effect of beam parameters on vortex beams propagating in atmospheric turbulence
The effect of beam parameters on the intensity profile of vortex beams propagating in the turbulent atmosphere and the scintillation properties of these beams are analyzed. A random phase screen model is utilized to perform this analysis. The scintillation properties are evaluated against the changes of topological charge, beam order, operating wavelength, receiver aperture side length, and source size parameters. The results show that using a flat-topped Gaussian vortex beam with a high topological charge causes a reduction in scintillation. Increasing the receiver aperture side length reduces the scintillation level. As the source size increases, scintillation decreases. The presented results also indicate that a flat-topped Gaussian vortex beam with high topological charges has less scintillation than the fundamental Gaussian beam. Moreover, the beams with higher topological charges and the ones operating at higher wavelengths preserve their beam profile better as they propagate. The beam order does not affect the beam profile. As the source size of the beam increases the intensity profile experiences dramatic changes concerning the beam propagating in free space. The findings of this dissertation will be useful in improving the performance of next-generation optical communication links and networks.
Analysis and design broadband microwave distributed amplifiers
In this thesis, microwave amplifier design techniques are analyzed and especially distributed technique is applied for broadband amplifier in L-S band according to the IEEE radar-frequency band. Conventional distributed amplifier (CDA) design topology is implied at 1-3 GHz frequency range. Available gain is obtained 14+2.5 dB with flatness. Optimum number of stages of amplifier is investigated and the result is evaluated as restriction of this topology so amplifier is designed with one stage. To increase gain performance cascaded single stage distributed amplifier (CSSDA) topology is analyzed and designed as 2-CSSDA at 1-3 GHz. In this design, almost 26 dB is obtained as peak value of available gain near 2.7 GHz and available gain is observed as 23.9+2 dB with simulations. CSSDA designed topology can be integrated with breakthrough circuit and approach so that more qualified distributed amplifier (DA) may be improved.
Investigation of makam correlation between Turkish art music and Turkish folk music
This thesis was made in order to understand makam concept mathematically with computer in Turkish music. The histogram and dynamic time warping (DTW) methods were used in this thesis. By using histogram method, similarities and dissimilarities of Hicaz makam art music songs and folk music songs, Acemkürdi makam art music songs, Kürdi makam art music songs, Muhayyerkürdi makam art music songs and sample seyirs of Hicaz makam were calculated. On the other hand,by using dynamic time warping method, similarities of Hicaz makam art music songs and folk music songs, sample seyirs of Hicaz makam, behaviour of Hicaz makam according to time axis and the distinctiveness of Hicaz makam art music songs and folk music songs with Acemkürdi makam art music songs, Kürdi makam art music songs, Muhayyerkürdi makam art music songs according to time axis were revealed. The obtained results show that the investigation depends on time axis, it means that using a dynamic time warping (DTW) gives more explicit results than the investigation independent of the time axis, that is made according to histogram graphs. In brief, using a dynamic time warping method is a more reasonable approach in terms of obtaining better results in Turkish music.