Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Drum Accompaniment Generation Using Midi Music Database and Swquence To Sequence Neural Network(Izmir Institute of Technology, 2022) Gümüştekin, Şevket; Gümüştekin, Şevket; 03.05. Department of Electrical and Electronics Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyThis thesis aims to create an artificial intelligence model to reinterpret the drum parts of musical pieces and/or to accompany music with new uniquely generated drum patterns. Besides providing rhythmic indicators, drum parts are essential to emphasize emotions. Every instrument in a musical composition is in harmony with each other to be meaningful as a whole. Based on this observation, in this thesis, a MIDI dataset and an LSTM based Seq2Seq model were used to create a link between different instruments and drums. Before the training, we created a dataset involving midi pieces with drum parts and grouped them as input and output, which are non-drum instruments, and drum parts respectively. The model was trained with six different genres and the teacher forcing method was utilized to improve the training. After the training, at the generation stage, we made it possible to adjust the complexity of the generated drum parts by changing the temperature value, which we called the complexity value, using the temperature sampling method. We also created a user interface with an instrument selection pane to give users control over the drum instruments generated. Moreover, we proposed a novel approach to generalize the idea for not only MIDI data but also WAV data. To accomplish this task, Mel-spectrogram, MFCC, and tempogram features were used. Both proposed methods are shown to produce high-quality unique drum accompaniments for different genres with adjustable complexity and freedom of choosing the desired drum instruments.Master Thesis Fiber Optic Current Sensor Interrogated by Phase-Sensitive Optical Time-Domain Reflectometer(Izmir Institute of Technology, 2022) Yüksel Aldoğan, Kıvılcım; Yüksel Aldoğan, Kıvılcım; 03.05. Department of Electrical and Electronics Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyIn this thesis, a novel method for current sensing using an FBG-assisted Phase-Sensitive Optical Time Domain Reflectomter (Phase-OTDR) with Mach-Zehnder Inter-ferometer is proposed. The detrimental effect of the intrinsic linear birefringence of the sensing fiber is solved by calibration. An FBG pair is written at the two ends of the spun fiber coil to eliminate phase fading and increase the measurement accuracy. A simulation tool was developed to study the feasibility of the approach and the sensor performance by a well-established Phase-OTDR model with the Jones formalism. The effects of bending-and FBG-induced linear birefringence are investigated as well as the impact of the detector noise.Master Thesis Development of Simulation Tool for Fbg-Based Phase-Otdr Vibration Sensors(Izmir Institute of Technology, 2021) Yüksel Aldoğan, Kıvılcım; Yüksel Aldoğan, Kıvılcım; 03.05. Department of Electrical and Electronics Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyOver the last twenty years, phase-sensitive optical time-domain reflectometer based distributed vibration sensors have attracted increasing attention as a research topic and commercial product. Due to their capability to detect external perturbations along fiber in real-time, they have found applications in several sectors such as oil\&gas pipeline monitoring, border security, transportation, and so on. Recently, the implementation of fiber Bragg gratings into these systems has become popular in order to improve sensing performance and several system configurations adopting a wide range of signal processing techniques have been presented. In this thesis, a simulation tool for distributed vibration sensing systems based on FBG-based phase-sensitive optical time-domain reflectometry is developed. In this context, firstly, the operation principle of optical time-domain reflectometry and system parameters affecting the performance are investigated. Secondly, fiber Bragg grating structures and their implementation into phase-sensitive optical time-domain reflectometer based vibration sensors are studied. By utilizing the one-dimensional impulse response model, fiber Bragg grating implementation-related problems, spectral shadowing crosstalk and multiple reflection crosstalk, and different sensor configurations are analyzed. Based on this model, the numerical simulation tool is developed by constructing fiber, fiber Bragg grating, and probe pulse structures. The operation of the developed simulation tool is verified by comparing obtained results with theory. Then, the capabilities of the developed tool are demonstrated by conducting several simulations with conventional Phase-OTDR and FBG-based Phase-OTDR configurations.Master Thesis Secure Beamforming for Millimeter Wave Communications(Izmir Institute of Technology, 2020) Özbek, Berna; Özbek, Berna; 03.05. Department of Electrical and Electronics Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyOver the last decade, many advancements have been made in the field of wireless communications. Among the major technology enablers being explored for the fifth-generation (5G) networks at the physical layer (PHY), a great deal of attention has been focused on millimeter-wave (mmWave) communications, massive multipleinput multiple-output (MIMO) antenna systems and beamforming techniques. These enablers bring to the forefront great opportunities for enhancing the performance of 5G and beyond-5G networks, concerning throughput, spectral efficiency, energy efficiency, latency, and reliability. At the meantime, the wireless communication is prone to information leakage to the unintended nodes due to its open nature. Hence, the secure communication is becoming more critical in the wireless networks. To address this challenge, the concept of Physical Layer Security (PLS) is explored. In this thesis, we examine the statistical mmWave transmission through linear beamforming techniques for PLS based systems. We propose the secure multiuser (MU) MIMO mmWave communications by employing hybrid beamforming at the base stations (BS), legitimate users and eavesdroppers. Using a 3 Dimensional mmWave channel model for each node, we employ the artificial noise (AN) beamforming to jam the channels of eavesdroppers and to enhance the secrecy capacity of the overall communication system. We investigate the secrecy performance on different scenarios including the single cell and multicell mmWave MU-MIMO downlink communications and reveal the key points directly related to the system security.Master Thesis Design, Development, Modeling and Control of a Stewart Platform(Izmir Institute of Technology, 2020) Tatlıcıoğlu, Enver; Tatlıcıoğlu, Enver; 03.05. Department of Electrical and Electronics Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyNeed for a six degrees of freedom test platform to be used in the inertial stabilization development tests of turrets, remote controlled weapon systems or sight systems is present in modern military technology development. To address this research issue, within this thesis study, a Stewart platform is built and is used for stabilization development tests of a sight system. To give a clear picture of the whole system, mechanical design criterion, electrical architecture, communication between system units and chosen hardware of the designed Stewart platform are presented in detail. After the design and development phases are completed, kinematic model is obtained via utilizing the computer–aided design model of the Stewart platform. The inverse kinematic expressions of the platform are made use of to calculate the required actuator behaviors for the platform to achieve the desired motion. Then, a cascade control structure is designed for control of both speed and position of the actuators where proportional integral controller is preferred. The designed control strategy is implemented to the Stewart platform where satisfactory performance is observed for it to be used in military vehicles.Master Thesis Periodic Disturbance Estimation Based Robust Control of Marine Vehicles(Izmir Institute of Technology, 2020) Kurtoğlu, Deniz; Tatlıcıoğlu, Enver; Tatlıcıoğlu, Enver; 03.05. Department of Electrical and Electronics Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyHighly uncertain and complex structures of marine vehicles render the control problem a challenging task. Moreover, the problem becomes much more challenging when the system is exposed to environmental disturbances. This thesis tackles this control problem with an adaptive robust control algorithm which is fused with a periodic disturbance estimation method. The periodic disturbance estimation method inspired from a Fourier series expansion technique is applied for compensation of environmental forces. In the first part of the thesis, an adaptive full state feedback backstepping controller which is supported with the periodic disturbance estimation method is applied. Stability of the closed–loop system and the convergence of the tracking error are established via Lyapunov based methods. Simulation studies are provided to support the theoretical results and to demonstrate the effectiveness of the proposed method. In the second part of the thesis, a nonlinear model free observer based adaptive output feedback controller in conjunction with the periodic disturbance estimator is designed. Lyapunov based arguments have been utilized to prove the stability of the closed– loop system, and the convergence of the tracking and observer errors under the closed– loop operation. Performance and viability of the proposed method are demonstrated via numerical simulations.Master Thesis Numerical and Experimental Investigations for Improving Dielectric Measurements With Microwave Cavities(Izmir Institute of Technology, 2020) Yaman, Fatih; Yaman, Fatih; 03.05. Department of Electrical and Electronics Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyIn this thesis, by utilising the inverse scattering problems approach, it was tried to improve the sensitivity in measuring the dielectric constants of the materials with microwave resonator cavities. The direct problem involves measurement of frequency shift and electric field/power values. The inverse problem aims to calculate the dielectric constant with the data obtained from the direct problem. First of all, the accuracy of the rectangular and cylindrical cavities operating in the S-band in the material perturbation method was compared with simulations, and how their sensitivity changes depending on the increasing frequency and dielectric constant was observed. Afterwards, dielectric constants were calculated by measuring the frequency shifts in the scope of the direct problem with a rectangular aluminium cavity for 3 different materials at the frequency of 1.254 GHz. However, this traditional method has a high error rate especially for samples with large dielectric constant or volume. For this reason, a measurement method based on Newton-Raphson iteration approach has been proposed. This proposed method uses power or electric field measurements at a particular frequency regardless of which mode is excited in the cavity. With the help of iterations based on an initial guess, the dielectric constant could be determined more precisely. Within the scope of this thesis, the results of the simulations performed with the Newton-Raphson method were given and the effect of the change of 3 different parameters of the method on the results was observed. In these simulations, iterations were carried out using electric field values at a certain number of points around the material. Finally, with the help of the spectrum analyzer, power measurements were taken from the 7-port aluminium cavity for the direct problem and the inverse scattering problem, which aims to recalculate the dielectric constant, was solved. More accurate results were obtained with the Newton-Raphson method.Master Thesis Design of an Offline Ottoman Character Recognition System for Translating Printed Documents To Modern Turkish(Izmir Institute of Technology, 2019) Küçükşahin, Naz; Ünlü, Mehmet Zübeyir; Ünlü, Mehmet Zübeyir; 03.05. Department of Electrical and Electronics Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyOptical character recognition (OCR) is one of the most studied topics for many years. As a result of these studies, systems developed especially for the Latin alphabet have become more accurate even for handwritten texts. However, there are very limited studies on Ottoman OCR systems in the literature and it is still a subject of interest due to the complexity of the language in grammar, writing and spelling. In this thesis, it is aimed to design an offline OCR system that recognizes Ottoman characters using deep convolutional neural networks. The proposed work consists of several steps such as image processing, image digitization and character segmentation, adaptation of inputs to the network, training of the network, recognition and evaluation of results. Firstly, a character dataset was created by segmenting text images of different lengths that was selected among scanned samples of various Ottoman literature from the digital database of Turkish National Library. Two convolutional neural networks of different complexity were trained with the created character dataset and the relationship between recognition rates and network complexity was evaluated. Secondly, using the Histogram of Oriented Gradients and Principal Component Analysis, the features of the created dataset were extracted and the Ottoman characters were classified with k-Nearest Neighbor Algorithm and Support Vector Machines which are widely used classification methods in the literature. The performed analyzes have shown that both networks provide acceptable recognition rates compared to the conventional classifiers, however complex deep neural network showed better accuracy and lower loss.Master Thesis Beam Selection Techniques in Millimeter Wave Communications(Izmir Institute of Technology, 2019) Cumalı, İrem; Özbek, Berna; Özbek, Berna; 03.05. Department of Electrical and Electronics Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyMillimeter wave (mmWave) communication is an advantageous technology which is capable of meeting the needs of future mobile networks. On the other hand, the propagation characteristics and system requirements are the restrictive factors for utilization of mmWave communication. Hybrid and digital beamforming architectures can be evaluated as worthy candidates to utilize mmWave communication. In the hybrid architecture, selection of a few number of beams by exploiting the sparse structure of the beamspace channel provides high spectral efficiency with low complexity. In this thesis, the multi-user mmWave communication in sparse and dense environments are investigated. Beam selection algorithms presented in the literature are performed for the sparse environment. While the number of users is equal to the number of radio frequency (RF) chains in a sparse environment, the number of RF chains is less than the number of users in a dense environment. Therefore, an algorithm which performs beam and user selection for the dense environment is proposed. The user selection in the proposed beam and user selection algorithm is performed based on the correlation among users’ channels. Since the users’ channels are highly correlated in mmWave communication, the proposed beam and user selection algorithm improves the spectral efficiency considerably. Furthermore, a non-uniform rectangular array (NURA) antenna configuration for mmWave communication is investigated when the digital beamforming architecture is employed. Then, a user selection algorithm is proposed under the case of lower number of antennas. The simulation results demonstrate the improvement in sum data rate through the proposed user selection algorithm in mmWave communication with NURA configuration.Master Thesis Elliptical Cavity Designs, Fabrications and Experiments To Investigate Cell Misalignment and Surface Roughness Effects(Izmir Institute of Technology, 2019) Karatay, Anıl; Yaman, Fatih; Karatay, Anıl; Yaman, Fatih; 01. Izmir Institute of Technology; 03.05. Department of Electrical and Electronics Engineering; 03. Faculty of EngineeringIn this thesis, the results of 5 different elliptical cavity designs at different cell numbers and frequencies and the fabrication and measurement of two of these are presented in order to investigate the effects of cell alignment error and surface roughness. First, a 9-cell, 3.9 GHz elliptical cavity with very poor cell-to-cell coupling is designed and the acceleration parameters are optimized. Thanks to the low cell-to-cell coupling, it is aimed to better observe possible mechanical defects and the effects of cell alignment errors in this cavity on the fundamental cavity parameters and particle-cavity interaction are investigated using CST-MWS program. In addition, the effect of surface roughness of the cavity on wake fields and impedances is among the parameters that are tried to be observed. Second, a 3-cell 2 GHz cavity and its scaled version, 3-cell 3.9 GHz cavity, are designed to demonstrate that the effects of cell misalignment were not limited to only this geometry, and similar simulations are repeated for these cavities. In the experimental part of the thesis, a 3-cell 3.9 GHz elliptical cavity with high cell-to-cell coupling is designed and fabricated with a 3D printer and made conductive by nickel and copper coating techniques. Then, the effects of cell misalignment on the quality factor and the electric field on the acceleration axis are investigated experimentally. For these processes, bead-pull measurement is utilized in addition to weak and critical coupling measurements. In the last part, a 2.45 GHz single cell aluminum cavity is fabricated, the same experiments are repeated and it is experimentally demonstrated that similar effects can also be observed with higher conductivity values.