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Electrical and Computer Engineering

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2019

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Articles 451 - 464 of 464

Full-Text Articles in Engineering

Adaptive Canonical Correlation Analysis For Harmonic Stimulation Frequencies Recognition In Ssvep-Based Bcis, Sahar Sadeghi, Ali Maleki Jan 2019

Adaptive Canonical Correlation Analysis For Harmonic Stimulation Frequencies Recognition In Ssvep-Based Bcis, Sahar Sadeghi, Ali Maleki

Turkish Journal of Electrical Engineering and Computer Sciences

Steady-state visual evoked potential (SSVEP) is the brain's response to quickly repetitive visual stimulus with a certain frequency. To increase the information transfer rate (ITR) in SSVEP-based systems, due to the frequency resolution restriction, we are forced to broaden the frequency range, which causes harmonic frequencies to come into the stimulation frequency range. Conventional canonical correlation analysis (CCA) may be associated with error for SSVEP frequency recognition at stimulation frequencies with harmonic relations. The number of harmonics considered to construct reference signals are determined adaptively; for frequencies whose second harmonic exists in the frequency range, two harmonics are used, and …


Segmented Character Recognition Using Curvature-Based Global Image Feature, Belaynesh Chekol, Numan Çelebi̇, Tuğrul Taşci Jan 2019

Segmented Character Recognition Using Curvature-Based Global Image Feature, Belaynesh Chekol, Numan Çelebi̇, Tuğrul Taşci

Turkish Journal of Electrical Engineering and Computer Sciences

Character recognition in natural scene images is a fundamental prerequisite for many text-based image analysis tasks. Generally, local image features are employed widely to recognize characters segmented from natural scene images. In this paper, a curvature-based global image feature and description for segmented character recognition is proposed. This feature is entirely dependent on the curvature information of the image pixels. The proposed feature is employed for segmented character recognition using Chars74k dataset and ICDAR 2003 character recognition dataset. From the two datasets, 1068 and 540 images of characters, respectively, are randomly chosen and 573-dimensional feature vector is synthesized per image. …


A Hybrid Of Fuzzy Theory And Quadratic Function For Estimating And Refining Transmission Map, Jyun-Yu Jhang, Chengjian Lin, Kuu-Young Young, Chin-Teng Lin Jan 2019

A Hybrid Of Fuzzy Theory And Quadratic Function For Estimating And Refining Transmission Map, Jyun-Yu Jhang, Chengjian Lin, Kuu-Young Young, Chin-Teng Lin

Turkish Journal of Electrical Engineering and Computer Sciences

In photographs captured in outdoor environments, particles in the air cause light attenuation and degrade image quality. This effect is especially obvious in hazy environments. In this study, a fuzzy theory is proposed to estimate the transmission map of a single image. To overcome the problem of oversaturation in dehazed images, a quadratic-function-based method is proposed to refine the transmission map. In addition, the color vector of the atmospheric light is estimated using the top 1\% of the brightest light area. Finally, the dehazed image is reconstructed using the transmission map and the estimated atmospheric light. Experimental results demonstrate that …


Lower Order Controller Design Using Weighted Singular Perturbation Approximation, Muhammad Raees Furquan Azhar, Umair Zulfiqar, Muwahida Liaquat Jan 2019

Lower Order Controller Design Using Weighted Singular Perturbation Approximation, Muhammad Raees Furquan Azhar, Umair Zulfiqar, Muwahida Liaquat

Turkish Journal of Electrical Engineering and Computer Sciences

Most of the analytical design procedures yield controllers of almost the same order as that of the plant. Resultantly, if the plant is of a high order, the controller obtained from these design procedures is also of a high order. The order of the controller should be practically acceptable for easy implementation. There are two indirect methods for designing a low order controller for high order plants: plant reduction and compensator reduction. In compensator reduction, the order of the controller designed for the original higher order plant is reduced. In plant reduction, the order of the plant is reduced for …


Diffusive Representation Modelling Thermal And Overvoltage For Permanent Magnet Synchronous Motor Fed By Voltage Inverter, Khaled Ben Smida, Moncef Ben Smida, Brahim Mrabet Jan 2019

Diffusive Representation Modelling Thermal And Overvoltage For Permanent Magnet Synchronous Motor Fed By Voltage Inverter, Khaled Ben Smida, Moncef Ben Smida, Brahim Mrabet

Turkish Journal of Electrical Engineering and Computer Sciences

Life of electric machines is very sensitive to temperature increases especially due to the fragility of their windings as well as to the overvoltage at the motor's terminals. Therefore, it is necessary to find the temperature in the most sensitive areas of the machine. It has been known for a long time that temperature rise is caused by the losses in the machine; thus, various models have been proposed. It has also been shown that the permanent magnet synchronous motor fed by a voltage inverter overheats more than the one supplied by a sinusoidal voltage. Indeed the permanent magnet synchronous …


A Modified Gravitational Search Algorithm And Its Application In Lifetime Maximization Of Wireless Sensor Networks, Sepehr Ebrahimi Mood, Mohammad Masoud Javidi Jan 2019

A Modified Gravitational Search Algorithm And Its Application In Lifetime Maximization Of Wireless Sensor Networks, Sepehr Ebrahimi Mood, Mohammad Masoud Javidi

Turkish Journal of Electrical Engineering and Computer Sciences

Recently, academic communities and industrial sectors have been affected by significant advancements in wireless sensor networks (WSNs). Employing clustering methods is the dominant method to maximize the WSN's lifetime, which is considered to be a major issue. Metaheuristic algorithms have attracted wide attention in the research area of clustering. In this paper, first a novel nature-inspired optimization algorithm based on the gravitational search algorithm (GSA) is defined. To control the exploitation and exploration capabilities of this algorithm, along with calculating the masses value, the tournament selection method is employed. Tournament size, the parameter of this method, is computed automatically using …


Defect Detection Of Seals In Multilayer Aseptic Packages Using Deep Learning, Kemal Adem, Cemi̇l Közkurt Jan 2019

Defect Detection Of Seals In Multilayer Aseptic Packages Using Deep Learning, Kemal Adem, Cemi̇l Közkurt

Turkish Journal of Electrical Engineering and Computer Sciences

Sealing in aseptic packages, one of the healthiest and cheapest technologies to protect food from parasites in the liquid food industry, requires a detailed and careful control process. Since the controls are made manually and visually by expert machine operators, the human factor can lead to the failure to detect defects, resulting in high cost and food safety risks. Therefore, this study aims to perform a leak test in aseptic package seals by a system that makes decisions using independent deep learning methods. The proposed Faster R-CNN and the Updated Faster R-CNN deep learning models were subjected to training and …


Improving Word Embeddings Projection For Turkish Hypernym Extraction, Savaş Yildirim Jan 2019

Improving Word Embeddings Projection For Turkish Hypernym Extraction, Savaş Yildirim

Turkish Journal of Electrical Engineering and Computer Sciences

Corpus-driven approaches can automatically explore is-a relations between the word pairs from corpus. This problem is also called hypernym extraction. Formerly, lexico-syntactic patterns have been used to solve hypernym relations. The language-specific syntactic rules have been manually crafted to build the patterns. On the other hand, recent studies have applied distributional approaches to word semantics. They extracted the semantic relations relying on the idea that similar words share similar contexts. Former distributional approaches have applied one-hot bag-of-word (BOW) encoding. The dimensionality problem of BOW has been solved by various neural network approaches, which represent words in very short and dense …


An Optimized Harmonic Elimination Method Based On Synchronized Microcontroller Architecture, Vivek Gopinath, Meenu Nair, Jayanta Biswas, Mukti Barai Jan 2019

An Optimized Harmonic Elimination Method Based On Synchronized Microcontroller Architecture, Vivek Gopinath, Meenu Nair, Jayanta Biswas, Mukti Barai

Turkish Journal of Electrical Engineering and Computer Sciences

This paper proposes an optimized synchronous PWM method for harmonic elimination in a quasi square wave inverter. The synchronized PWM method enables online harmonic computation and PWM pulse generation in a multitasking digital controller to eliminate lower order harmonics. The multitasking digital controller reduces the look-up table requirement and helps in realizing efficient implementation to eliminate dominant harmonics. This method offers a simple scalable solution for combined fifth and seventh harmonic elimination using two low-cost eight-bit PIC microcontrollers (PIC18F4550, PIC18F452). Experimental results are demonstrated for a single-phase three-level inverter. The proposed method achieves 90$\% $ reduction of fifth and seventh …


An Improved Space Charge Distribution Analytical Model To Assess Field-Effect Transistor's Intrinsic Capacitors, Saif Ur Rehman, Umer Farooq Ahmed, Muhammad Mansoor Ahmed, Umair Rafique Jan 2019

An Improved Space Charge Distribution Analytical Model To Assess Field-Effect Transistor's Intrinsic Capacitors, Saif Ur Rehman, Umer Farooq Ahmed, Muhammad Mansoor Ahmed, Umair Rafique

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, an analytical model has been developed for improved assessment of Miller capacitors for high-frequency metal?semiconductor field-effect transistors. Depletion layer underneath the Schottky barrier gate has been divided into four distinct regions, and by evaluating the charges associated with each region, gate-to-source ($C_{GS}$) and gate-to-drain ($C_{GD}$) capacitors, {commonly known as Miller capacitors,} have been defined accordingly. Mathematical expressions have been developed both for the linear as well as for the saturation region. Miller capacitors and their variation as a function of applied bias have been assessed. It has been shown that the proposed technique offers better accuracy in …


A Hybrid Multiband Printed Loop Antenna For Wlan/Wimax Bands For Applications In Mimo Systems, Ali Shahshahani, Mohammad Amin Honarvar Jan 2019

A Hybrid Multiband Printed Loop Antenna For Wlan/Wimax Bands For Applications In Mimo Systems, Ali Shahshahani, Mohammad Amin Honarvar

Turkish Journal of Electrical Engineering and Computer Sciences

In this article a thin hybrid multiband printed loop antenna is presented for application in multiple-input multiple-output (MIMO) systems. The proposed antenna has several advantages; for example, the pseudofilter feature of the proposed antenna is one of this antenna's advantages. Because of the antenna's width ($9.5$~mm), it can be used on the edges of the board. The first resonant frequency is generated by the original loop of the antenna. Incorporation of different embedded components, i.e. a subsidiary loop, extended ground-traces, parasitic patch, and the slits, results in the proposed antenna resonating as a multiband antenna. This antenna is adjusted in …


Multiple Distributed Generations Placement And Sizing Based On Voltage Stability Index And Power Loss Minimization, Oumaima Garfi, Helmi Aloui Jan 2019

Multiple Distributed Generations Placement And Sizing Based On Voltage Stability Index And Power Loss Minimization, Oumaima Garfi, Helmi Aloui

Turkish Journal of Electrical Engineering and Computer Sciences

This paper proposes a rapid analytical method to determine the locations and sizes of multiple distributed generations (DGs) inside a distribution network. DGs locations are chosen with the aim of enhancing voltage stability and their sizes are picked so as to minimize system power losses. To evaluate the effect of the DG's nature on the system's performance, the proposed DG allocation method is tested for all DG types and the impact of the combination of different types of DGs is equally investigated, which offers a guide to designing an optimal hybrid network.


Optimal Siting, Sizing, And Parameter Tuning Of Statcom And Sssc Using Mpso And Remote Coordination Of The Facts For Oscillation Damping Of Power Systems, James Garba Ambafi, Sunusi Sani Adamu Jan 2019

Optimal Siting, Sizing, And Parameter Tuning Of Statcom And Sssc Using Mpso And Remote Coordination Of The Facts For Oscillation Damping Of Power Systems, James Garba Ambafi, Sunusi Sani Adamu

Turkish Journal of Electrical Engineering and Computer Sciences

In electromechanical oscillation damping within power system, power system stabilizers (PSSs) are often deployed. However, a PSS is less effective in damping interarea oscillation and is limited by changes in network configuration due to weak tie-lines and load variations. Consequently, this paper presents a wide-area coordination approach that damps interarea oscillations using FACTS devices and phasor measurement units. We selected a static synchronous compensator (STATCOM) and static series synchronous compensator (SSSC) for realistic power system interarea oscillation damping. The performance of the coordinated FACTS installed in a power system depends on their suitable locations, sizes, tuned parameters, and remote input …


Quantification Of Resistive Wall Instability For Particle Accelerator Machines, Fati̇h Yaman Jan 2019

Quantification Of Resistive Wall Instability For Particle Accelerator Machines, Fati̇h Yaman

Turkish Journal of Electrical Engineering and Computer Sciences

The aim of this study is to quantify longitudinal resistive wall impedances, corresponding wake functions, and wake potentials for different accelerator machines of interest. Accurate calculations of wake potentials by particle-in-cell codes are extremely difficult for the investigated parameters; therefore, we use an analytical approach and consider large domains with fine discretization for the required numerical integrations. The semianalytical wake potential computations are benchmarked against numerical general purpose 2D/3D Maxwell solver software codes and a different analytical approach for a certain set of parameters. We report examples to illustrate limitations of wake potential estimations from coupling impedances, and computations for …