Department of Electrical & Electronics Engineering
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Browsing Department of Electrical & Electronics Engineering by Subject "electrical & electronics engineering"
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Item A DATA COLLECTION SYSTEM DESIGN FOR HAND GESTURES(2022-02-14) Akan, Erhan; Uslu, İbrahim Baran; Akagündüz, ErdemIn this study, we aim at designing a smart glove, which consists of different inertial sensors and an EMG sensor and developing a human-machine interaction application by pre-processing and fusing these different sensory data. We also aim at providing solutions in cases where image processing-based approaches are inefficient. In the proposed smart glove, the quartenion-based orientation data to be produced by the magnetometer and gyroscope together, the acceleration data to be generated by the accelerometer, and the analog data generated by the EMG sensor are collected and then prepared for use by different applications.Item A PRACTICAL TIME SYNCHRONIZATION ALGORITHM FOR LINEAR WIRELESS SENSOR NETWORKS INCLUDING LINK-LAYER PROTOCOL IMPLEMENTATION(2022-01-24) Al Imran, Md Abdullah; KARA, AliTime synchronization is of tremendous importance in networked systems, especially in distributed network systems namely Wireless Sensor Networks (WSNs). WSNs extensively utilizes the time synchronization aspect for coordination and correlation of distributed entities and events (e.g., data fusion, synchronized sleeps and wake-ups, channel sharing etc.). They are typically designed with very stringent constraints, due to their inherent properties like limited resources of energy, storage, computation and bandwidth combined with the ambient conditions and application specific require ments, making traditional synchronization methods unfeasible. Hence, numerous design parameters including the form factor, precision, processing time and power, memory, overhead traffic, efficiency and scalability has led to extensive research of time synchronization relevant to WSNs over the past decades. In this paper, we inves tigate the linear WSNs or LWSNs and propose a network wide time synchronization method for a multi-hop linear network along with a robust protocol. Furthermore, the protocol is equipped with data aggregation and simple error handling features. Instead of proposing a new algorithm, we will reuse an existing synchronization algorithm. The system was tested on realistic test-beds. Through experimentation we conclude that increasing the synchronization window increases the synchronization accuracy with a shorter network lifetime. Moreover, the joint impact of relative offset only, and relative offset and drift on the synchronization accuracy was studied. Tests exhibit a higher accuracy for smaller synchronization windows i.e. use of offset parameter only is sufficient to achieve tolerable levels of accuracy. Needless to say, the energy consumption also can be lowered using offset only during time synchronizations for shorter windows.Item A STUDY ON MICROSTRIP ANTENNA DESIGN FOR 77 GHZ RADAR SYSTEMS(2023-01-20) YILMAZ, Selen; KARA, Ali; DALVEREN, YaserThis thesis presents a comprehensive investigation into the design and operational behavior of series-fed microstrip patch antenna array for the 77 GHz automotive radar. Initially, the theoretical background information on the theory of microstrip antenna, patch antenna array, frequency scanning array and Chebyshev array are provided. A full-wave finite element method-based simulation tool is used to design and slightly tune the dimensions of the antennas as a parametric study. At the first stage, a series fed linear Chebyshev patch array with resonance at 76.5 GHz is designed representing one transmit channel of the antenna. Shorting pins are loaded to transition structure of ground-signal-ground (GSG) padding to enhance the total gain. Comparative analysis between vialess and via loaded cases is conducted in terms of bandwidth and gain. At the last stage, 76.5 GHz linear patch antenna array is converted into a 79 GHz linear patch antenna array by optimizing the GSG padding dimensions, scaling the spacings between each two adjacent array elements and the length of array elements. Two designs are proposed to assess the effect of scaling method at this stage. Comparative analysis in terms of the beam steering angle, the impedance bandwidth, the overall gain and the sidelobe level suppression is conducted between these two designs. Keywords: Dolph-Chebyshev Distribution, Frequency Scanning Array, Linear Array, mmWave, Patch Array Antenna.Item A STUDY ON PERFORMANCE ANALYSIS OF SPACE TIME BLOCK CODING IN MULTIPLE INPUT MULTIPLE OUTPUT WIRELESS COMMUNICATION SYSTEMS(2022-01-13) GHANEM, KAMAL DAW; KARA, AliBuilding a Multiple Input Multiple Output (MIMO) channel to face real-world fading and noise efficiently needs good diversity and coding techniques. Space-time block code techniques of MIMO system can achieve huge performance gains in multipath fading wireless links. It has evolved as a most vibrant research area in wireless communications. Recently, STBC has been trying to incorporate in the forthcoming generation of mobile communication standard which aims to deliver true multimedia capability. The aim of this thesis study is to provide a two different encoding schemes of STBC depending on the selection for rate and number of transmit antennas, provide an Alamouti STBC encoding, an orthogonal STBC encoding and linear decoding technique while offering full diversity benefits in MIMO system. Our design aims to improve Bit Error Rate (BER) performance, increase the diversity order with less complexity in receiver, and improve error performance of synchronous data links without sacrificing data rate or requiring more bandwidth. The simulations have been done in MATLAB Simulink® 2020 environment. Simulation results have been compared in MIMO fading channel for QPSK modulation, which provide better BER performance in Rician fading channel compared to the Rayleigh fading channel. However, performance of the implemented MIMO-STBC depending on the selection for code rate and diversity order. By using Alamouti STBC, full diversity is accessible to the 2 x 8, whereas orthogonal STBC to the 4 x 8 MIMO system. Therefore, better results are produced if the received side uses maximum number of antennas. Diversity clearly depends on the number of receive antennas so it diversity and receive antennas are directly proportional. The simulation results show that the Orthogonal STBC design by various code rates can efficiently reduce the BER at the same time reduce signal – to - noise ratio (SNR).Item AGILE SOFTWARE MAINTENANCE AND DEVELOPMENT USING CLOUD COMPUTING FRAMEWORK(2023-01-26) ALMASHHADANI, Mohammed; YAZICI, Ali; MISHRA, AlokAgile methods have emerged to overcome the obstacles faced in traditional software methodologies, such as the Waterfall, Prototype, Spiral, etc. There have been many studies that show the numerous features of the Agile methodologies, making them useful for software development. However, many studies have also proposed a framework to adapt the Agile methods to Cloud Computing to leverage the benefits from this environment. The existing studies focus on the adaptive development life cycle for Agile with the Cloud, but have so far been unable to include the maintenance process in a detailed manner. Among these attempts and as further contribution, the present work intends to introduce Agile software maintenance and development using Cloud Computing framework (ASMDCC) as a reference for developing software with the Cloud in respect of maintenance activities. The case study findings reveal that the combination of Agile with Cloud Computing can resolve the major issues faced in traditional software maintenance, making the role of this approach significant in globally/distributed software maintenance. Furthermore, it is shown that Cloud Computing services play a vital part in resolving software maintenance. Finally, the results indicate that using the ASMDCC framework improves the challenges faced by the maintenance team compared to the traditional environment regarding management, infrastructure, collaboration, and transparency.Item AN EXPERIMENTAL STUDY ON NEAR GROUND RADIO PROPAGATION AT 900 MHZ(2022-01-21) BİLGİÇ, BURCU; KARA, Ali; AYDIN, ElifThe aim of this study is to analyze outdoor radio signal propagation according to experimental results. This thesis includes empirical data gathered from outdoor links on suburban and urban areas in Ankara. Path loss measurements at sub GHz are presented in five different outdoor environments. Path loss measurements were taken at different receiver and transmitter antenna heights. Furthermore, curve fittings arose from measurements over Line of Sight (LOS) and Non-Line of Sight (NLOS) links in outdoor environments are provided. This study clarifies the efficient usage of wireless devices in different outdoor links. This thesis provides cataloging about different antenna heights and different terrain path loss modeling and creating formulas by using curve fitting. A new model involving antenna height effects and terrain effects on path loss is presented. Also, previous literature models are compared with the presented models.Item AN EXPERIMENTAL STUDY ON TIME SYCHRONIZATION IN LINEAR SPANNING TREE WIRELESS SENSOR NETWORK(2022-02-17) Erpay, Ahmet; Kara, AliIn this study, time synchronization in a linear spanning tree wireless sensor network is studied. The method is applied on a PIC based platform where time synchronization process and temperature effects on it are focused. Outdoor experiments are fused with temperature change and the aim is to see performance of the wireless sensor network and to overcome possible challenges.Item ANALYSIS AND QUANTIZATION OF RANGE ERROR OF MODULAR FMCW RADAR AT C BAND(2022-02-28) Abdulrazigh, Mahfoud Y. A.; Kara, AliThis thesis presents the experimental analysis of range error of modular FMCW (frequency modulated continuous wave) radar operating at C-band. FMCW radar is a type of radar where frequency modulation is used in signal transmission. FMCW radar can measure both range and speed of targets. One of the problems in the design of modular FMCW radar is errors due to time delays in components and/or modules such as cables, PA, LNA and antenna (Measurement Instrumentation Delay-MID). Then, MID is taken into account to improve the accuracy of range measurement, and range error is quantized. Time delay (MID) causes frequency offset in measured beat frequency resulting in range error. Therefore, the resulting frequency offset of the radar is estimated and quantized experimentally. In this way, a mean error of about 11cm was achieved within 9m range measurements for C Band modular FMCW radar.Item ANALYSIS OF OPTOELECTRONICS MATERIALS(2017-05-02) ALQURQASH, AYOOB YOUSIF AHMED; Eseller, EfeOptoelectronic is a section of electronics which deals with emitting and detecting of light such as LEDs, solar cells, transistors, photodetectors. These devices synthesis of materials (Silicon, MWCNTs, SWCNTs and Graphene) has a possibility to convert the incident radiation light in to electric power or vice versa. This thesis reviews the analysis of optoelectronic materials in particular for graphene material which represents the latest episode of the explorations of the origin of materials from carbon (graphite, fullerene, CNT, MWCNTs, SWCNTs and Graphene) and highlight the exceptional properties of MWCNTs and graphene by using Raman theory. An implementation, including experiment in a laboratory on MWCNTs sample by using Raman system which inclueds spectrometer with power laser (200mW, 100mW, 50mW) and wavelength 532nm.Item BACKSTEPPING CONTROL OF DC ELECTRICAL MACHINES(2017-01-07) Zuglem, Ahmad; Doruk, Reşat ÖzgürThis thesis reviews a linear backstepping design scheme for the control of DC motor system to achieve the desired position and speed tracking control objective. This technique is based on the use of the linear system in the DC motor model and finding a direct relationship between the motor output and input quantities without affecting the speed regulation. The proposed control scheme is not only to stabilize the DC motor, but also to drive the speed tracking error and the position error are able to converge to zero asymptotically according to Lyapunov stability theorem. The backstepping control approach is applied to the control of direct current electric motors. The approach is based on the extension of the Lyapunov’s second method which is applied to each state separately by interconnecting them by introducing virtual control inputs to each state equation. The stability of the closed loop is ensured by tuning the final Lyapunov equations appropriately. The disturbance torques might become a critical issue in this case and the issue is handled by doing a theoretical analysis based on input-to-state stability theory and numerical simulations with disturbance torques as random signals.Item COMPARATIVE ANALYSIS OF MPPT TECHNIQUES FOR SOLAR AND WIND SYSTEMS UNDER DIFFERENT OPERATING CONDITIONS(2022-12-26) AHMAD, Muhammad Saeed; SÜNTER, SedatRenewable energy technologies have gained a lot of traction in the last few decades as a means of reducing reliance on fossil fuels and mitigating the impact of climate change. Renewable sources such as sunlight, wind, and water are clean and sustainable. These technologies have gained significant attention in recent years. While renewable energy technologies have many advantages, one of the main challenges is their relatively low efficiency compared to fossil fuels. As a result, renewable energy systems typically require more land and resources to produce the same amount of energy as fossil fuel-based systems. Additionally, the efficiency of renewable energy systems can vary depending on the weather and other environmental conditions. For example, solar panels are less effective on cloudy days and wind turbines are less effective in calm weather. This can make it difficult to predict and control the amount of energy that renewable systems will produce, which can create challenges for integrating them into the grid. The problem with efficiency can be dealt with the use of maximum power point tracking (MPPT) techniques. These techniques are used to optimize the performance of renewable energy systems by ensuring that they operate at the maximum power point, or the point at which they can generate the most power. There are several types of maximum power point tracking (MPPT) techniques, but they can be broadly classified into three categories: simple, artificial intelligence (AI), and hybrid. Simple MPPT techniques such as PO and IC are the most basic and widely used type of MPPT. These techniques use relatively simple algorithms to continuously adjust the operating conditions of the system to maintain the maximum power point. AI-based MPPT techniques like PSO and ANN use advanced algorithms and machine learning techniques to optimize the performance of renewable energy systems. These techniques can adapt to changing environmental conditions and can continuously adjust the operating conditions of the system in real-time. Hybrid MPPT techniques like ANFIS and PSO&PO are a combination of simple and AI based techniques. These techniques use simple algorithms to quickly track the maximum power point, and then use AI-based techniques to fine-tune the operating conditions of the system in real-time. A comparative analysis of simple, AI, ML, and hybrid MPPT techniques for hybrid energy (Solar and Wind) systems is discussed in this thesis. The MPPT algorithms were ranked based on different metrics such as efficiency, settling time, oscillations at MPPT and algorithm complexity. For PV system, AI based techniques performed best as compared to Hybrid and conventional techniques. For Wind system, hybrid techniques yield the best results as they combine the benefits of conventional and AI techniques.Item COMPARATIVE ASSESSMENT OF SIMPLE AND ACCURATE LOCALIZATION METHODS BASED ON TDOA-AOA MEASUREMENTS(2022-01-10) ZEGLAM, MOHAMED; Dalveren, YaserThis thesis is aimed to determine a simple but effective localization method for estimating the position of a stationary emitter by utilizing both Time Difference of Arrival (TDOA) and Angle of Arrival (AOA) measurements to be used an ongoing project. For this purpose, firstly, literature survey is conducted for the methods used to estimate the position of a stationary emitter through the TDOA measurements. Then, hybrid methods that utilize both TDOA and AOA measurements together for emitter localization are reviewed. Among these methods, the simplest but accurate methods are determined, namely Least Squared (LS) method and Weighted Least Squared (WLS) method. Next, simulations are conducted to examine the accuracy of these methods under various simulation scenarios considering the different number of sensors and TDOA measurement errors. With the help of simulation results, the performance of the methods are comparatively assessed in terms of estimation accuracy. From the results, it can be concluded that WLS method provides better accuracy under high measurement error and high number of sensors.Item COMPARATIVE ASSESSMENT OF SWITCHING OPTIONS FOR BACK TO BACK ANTENNAS IN WIRELESS NETWORKS(2022-01-26) DURUKAN, Ahmet Mert; DALVEREN, Yaser; KARA, AliThis thesis mainly aims to provide bidirectional sensor node link communication with neighboring sensor nodes. The connection between the antennas to create a wireless sensor link is provided by using RF Switch and RF Splitter / Combiner designs. The performance evaluations of these two designs are determined as objectives. Measurements are also taken in the LOS and NLOS conditions. The data obtained from the measurement were evaluated in terms of total cost, energy consumption and maximum distance.Item COMPARISONS OF COMPUTER-BASED PROPAGATION MODELS WITH EXPERIMENTAL DATA COLLECTED IN AN URBAN AREA AT 1800 MHz(2017-09-06) ACAR, Tarık; AYDIN, ElifNowadays a lot of models are set for the efficient and economic usage of frequency band which is a limited source. In this thesis, propagation models, developed and accepted in literature for this purpose, were studied. These are Free Space Path Loss (Fspl) + RMD (Epstein-Peterson), COST-HATA and COST-WI models. The district chosen for the model application has an irregular structure style. In the application of Free Space Path Loss (Fspl) + RMD (Epstein-Peterson), RTV Plan software is used; the other models were applied by calculations. In order to compare the success of the models, electric field strength measurements were taken in the chosen district (Mustafa Kemal Mahallesi-ANKARA), firstly at the random coordinate and secondly coordinates tracking on a single line. As a conclusion, measured values were compared with the results which were taken from the mentioned models with graphical presentations and the most appropriate model is tried be found and as another aim of the thesis study, a correction factor was generated as a modification for COST – HATA propagation model.Item CONTROL OF BIFURCATIONS IN COUPLED FITZHUGH-NAGUMO NEURONS(2022-02-28) ABDALLH, AMMAR; Doruk, Reşat ÖzgürA pair of identical Fitzhugh-Nagumo neuron models are coupled together through a gap junction (electrical synapse). These neurons are excited by external current. We have represented the system as an electrical circuit and the gap as synaptic conductance. The complete system is a nonlinear multi-input, multi-output (MIMO) type. By using bifurcation theory and the MATLAB based software package called MATCONT we tracked the neuron parameters that lead to bifurcation conditions. Actually, any change in the structure and the function of the synapse causes severe psychiatric and neurological disorders. So that, we studied the couple of the (F-N) model by selected different values of the synaptic conductance. For each value of the synaptic conductance we analyzed the bifurcations for the parameters of the neurons one-by-one using MATCONT. After that, we designed a controller to correct the defective in a neuron activity caused by the change in synaptic conductivity and the change in the neurons parameters. In this research, a washout filter controller of the second order type is used. This controller provides an electrical current injection to control the unwanted behavior of the neurons due to parametric bifurcations. Linear Quadratic Regulator (LQR) supported by projective control theory, serves as the reference method in the design of the controller.Item CONTROL OF BIFURCATIONS IN THE FITZHUGH-NAGUMO NERVE CELL DYNAMICS(2017-04-04) Ihnish, Hamza; DORUK, Reşat ÖzgürA theoretical bifurcation control strategy is presented for a single Fitzhugh- Nagumo (FN) type neuron. The bifurcation conditions are tracked for varying parameters of the individual FN neurons. A MATLAB package called as MATCONT is utilized for this purpose and all parameters of the neuron is analyzed one-by-one. Analysis by MATCONT revealed five Hopf (H) and one Limit-Point/Saddle Point (LP) bifurcation. In the control of bifurcations two different approaches are studied. The first one is a full state feedback technique based on the approach of servo control by pole placement. The other one employs a washout filter and an output feedback concept is utilized to process the outputs of the washout filter. In this research, the output feedback technique will be based on linear quadratic projective control theory. Washout filters designed as a first order one that filters only membrane potential and second order one that filters both membrane potential and recovery variable. As washout filters are naturally high-pass systems thay block the steady states inputs so that the original equilibrium points do not change. This phenomenon will especially be noted in Hopf Bifurcation cases. In addition to those first order washout filter which is also physically applicable (due to a single feedback from membrane potential) appeared to be more advantageous than the second order version.Item CONTROL OF ELECTRIC POWER GENERATORS AND THEIR SYNCHRONIZATION(2017-01-07) ALSHAMMARI, ZAIDOON WALEED JAWAD; DORUK, Reşat ÖzgürWe present a simulation based study focusing on the application of a nonlinear control technique to stabilize and control the terminal voltage and power angle of a small synchronous generator driven by a steam turbine engine. The control technique is based on integrator back-stepping techniques which is an application of the second method of Lyapunov to the states of a nonlinear dynamical system one-by-one recursively. The theory is applied to two cases. The first one is the combined control of power angle and terminal voltage of a single generator. The second one is the synchronization of the power angles and terminal voltages of multiple generators (two or more). Upon obtaining a successful and stable generator control system for a main generator, we replicated the controller for another generator and feed the second generator’s reference inputs from the first generator’s outputs (power angle and terminal voltage of the main generator). The second generator has the same controller design. The same approach is applied to a three generator case. All the generators are assumed identical and same controller designs can be applied. Simulations are presented to verify the approaches developed in this research. Results showed that the control algorithms work satisfactorily in both single generator and multiple generator cases. In the synchronization of multiple generators, the second and later generators have a very small delay.Item DEEP LEARNING APPLICATIONS IN SEIZURE DETECTION(2022-02-24) Kadhim, Yezi Ali; Mishra, Alok; Garg, LalitIn this thesis, a new method is proposed based on deep auto encoder and power spectral density. First, the input data is analyzed using power spectral density for feature extraction by measuring the power spectral density of the signal for each row of data. The produced output becomes input to the first Auto encoder to reduce the dimension and extracted high level features. The output of first auto-encoder become input to the second auto-encoder also to reduce number of features and extracted high level features. In addition, these features are classified into two groups: normal and abnormal by using SoftMax classifier. Finally, the two auto-encoders and SoftMax stacked and trained by using backpropagation algorithm to improve the classification accuracy. The proposed method gives satisfactory results when compared with the common methods presented in this filed .Here, the number of Auto encoders depend on the behavior of the data as well as the dimension. The proposed method is tested with commonly used datasets in the epilepsy serius detection, and the results obtained are compared with other and most prominent works in this field in order to determine the strengths and weaknesses.Item DEEP LEARNING BASED VEHICLE CLASSIFICATION FOR LOW QUALITY IMAGES(2022-03-10) TAŞ, Sümeyra; DALVEREN, Yaser; PAZAR, ŞenolWith the increase in the population, the number of vehicles used in transportation is increasing. Vehicle classification is a need in various areas such as automatic toll collection systems, traffic control systems, intelligent transportation systems or autonomous vehicles and more. Convolutional Neural Network, is a part of deep learning and is called CNN in brief, is a well-known model for vehicle classification with visual data. However, there are not many applications that touch upon low quality images. This work presents that CNN models can be run and used with low quality images for a vehicle classification project by using a 2 MP standard security camera. In addition, this work presents three CNN models which are built from scratch, VGG16 pre-trained network for feature extraction, and VGG16 pre-trained network for fine-tuning by running its own less dataset. Promising results achieved from the experiments show that it is possible to classify vehicles even a dataset containing low quality images is used.Item DESIGN AND DEMONSTRATION OF LOW COST MODULAR FMCW RADAR FOR EDUCATIONAL PURPOSES(2022-01-17) Ovais, Ibrahim; KARA, AliFMCW radar uses a continuous wave frequency modulated signal. Frequency modulation (FM) is used because the continuous wave radar cannot measure the target distance. Target distance and speed can be easily measured with the FMCW radar. Also, FMCW provides pretty good range resolution. In this thesis, an FMCW radar design for educational and research purposes and indoor tests are reported . The radar operates in the 4.4-4.9 GHz band (500 MHz bandwidth) and provides very good range resolution. The modular radar uses a simple, inexpensive and readily available platform for signal processing. Within the scope of the study, test and demonstration studies of the radar are carried out in a laboratory environment, and its performance under simple laboratory clutter is examined.