Heuristic Methods For Postoutage Voltage Magnitude Calculations,
2016
TÜBİTAK
Heuristic Methods For Postoutage Voltage Magnitude Calculations, Oğuzhan Ceylan, Aydoğan Özdemi̇r, Hasan Dağ
Turkish Journal of Electrical Engineering and Computer Sciences
Power systems play a significant role in every aspect of our daily lives. Hence, their continuation without any interruption (or with the least duration of interruption due to faults or scheduled maintenances) is one of the key aims of electrical energy providers. As a result, electrical energy providers need to check in great detail the integrity of their power systems by performing regular contingency studies of the equipment involved. Among others, line and transformer outage simulations constitute an integral part of an electrical management system. Both accuracy and calculation speed depend on the branch outage model and/or the solution algorithms …
Towards A Semantic-Based Information Extraction System For Matching Résumés To Job Openings,
2016
TÜBİTAK
Towards A Semantic-Based Information Extraction System For Matching Résumés To Job Openings, Duygu Çeli̇k
Turkish Journal of Electrical Engineering and Computer Sciences
A curriculum vitae or a résumé, in general, consists of personal details, education, work experience, qualifications, and references. The overall objective of this study was to extract such data as experience, features, and business and education information from résumés stored in human resources repositories. In this article, we propose an ontology-driven information extraction system that is planned to operate on several million free-format textual résumés to convert them to a structured and semantically enriched version for use in semantic data mining of data essential in human resources processes. The architecture and working mechanism of the system, similarity of the concept …
Lifetime Maximization Of Wireless Sensor Networks Using Particle Swarm Optimization,
2016
TÜBİTAK
Lifetime Maximization Of Wireless Sensor Networks Using Particle Swarm Optimization, Aleem Kabeer Mir, Muhammad Zubair, Ijaz Mansoor Qureshi
Turkish Journal of Electrical Engineering and Computer Sciences
Wireless sensor networks have multiple applications in intelligent environment and structural monitoring. The major challenge in wireless sensor networks is the power constraint. This paper deals with minimizing the energy utilization of wireless sensor nodes and maximizing their overall life span. The objective of our proposed scheme is to find a method for grouping sensors into the maximum number of distinct sensor cover sets to totally monitor the required area. This problem can be solved by using the disjoint cover set problem. Present optimization techniques take much time and deliver unsatisfactory results in large-scale networks. This paper proposes a technique …
Amplitude-Phase Control Of A Novel Chaotic Attractor,
2016
TÜBİTAK
Amplitude-Phase Control Of A Novel Chaotic Attractor, Chunbiao Li, İhsan Pehli̇van, Julien Clinton Sprott
Turkish Journal of Electrical Engineering and Computer Sciences
A novel chaotic attractor with a fractal wing structure is proposed and analyzed in terms of its basic dynamical properties. The most interesting feature of this system is that it has complex dynamical behavior, especially coexisting attractors for particular ranges of the parameters, including two coexisting periodic or strange attractors that can coexist with a third strange attractor. Amplitude and phase control methods are described since they are convenient for circuit design and chaotic signal applications. An appropriately chosen parameter in a particular quadratic coefficient can realize partial amplitude control. An added linear term can change the symmetry and provide …
An 11-Switch Multilevel Inverter With A Modified Space Vector Modulation,
2016
TÜBİTAK
An 11-Switch Multilevel Inverter With A Modified Space Vector Modulation, Nasrudin Abd Rahim, Hew Wooi Ping, Jafferi Jamaludin
Turkish Journal of Electrical Engineering and Computer Sciences
This paper proposes a new 3-phase multilevel inverter that is able to generate 7 levels in line-to-line voltage with only 11 switches. The inverter is formed from the 6-switch conventional full-bridge topology with the addition of 5 bidirectional switches in which 2 of them are shared among the three phases. By doing so, the number of power switches can be minimized, thus reducing the complexity in generating and controlling PWM signals. A novel voltage control scheme based on space vector modulation is developed by introducing a virtual vector in every sector of the vector hexagon. This is to overcome the …
Papr Reduction Using Genetic Algorithm In Lifting-Based Wavelet Packet Modulation Systems,
2016
TÜBİTAK
Papr Reduction Using Genetic Algorithm In Lifting-Based Wavelet Packet Modulation Systems, Necmi̇ Taşpinar, Yüksel Tokur Bozkurt
Turkish Journal of Electrical Engineering and Computer Sciences
Wavelet packet modulation (WPM) is a potential candidate in wireless communication systems by virtue of its flexibility and modular implementation capability. However, WPM suffers from high peak-to-average power ratio (PAPR), which results in signal distortion when a high-power amplifier is employed at the transmitter. The partial transmit sequence (PTS) is an attractive PAPR reduction method, but its computational complexity is high. In this paper, we propose a PTS based on the genetic algorithm (GA) scheme (GA-PTS) to reduce the computational complexity of the PTS in the lifting-based WPM (LBWPM) systems. Simulation results show that the proposed GA-PTS scheme provides significant …
Rlc Circuit Extraction With The Differential Evolution Algorithm For Conducted Electromagnetic Emission Model Of Integrated Circuits, Muhammed Emi̇n Başak, Ayten Kuntman
Turkish Journal of Electrical Engineering and Computer Sciences
This paper examines the modeling of conducted electromagnetic emissions of integrated circuits. In this study, test circuits were designed and printed circuit boards were prepared to measure the input impedance at the power supply pin of the microcontroller. After S-parameter measurements of the test circuit were performed in a frequency range of 10 MHz to 2 GHz, Z-parameters were obtained via S-parameters. Next, the impedance--frequency curve of the test circuit's power supply pin, which consists of a microcontroller core, printed circuit board, conductive trace, and SMA connector global impedances, was obtained. Therefore, all the traces, printed circuit board, and SMA …
A Robust Estimator-Based Optimal Algebraic Approach To Steam Generator Feedwater Control System,
2016
TÜBİTAK
A Robust Estimator-Based Optimal Algebraic Approach To Steam Generator Feedwater Control System, Günyaz Ablay
Turkish Journal of Electrical Engineering and Computer Sciences
Feedwater control systems are used to maintain the steam generator water level within prescribed narrow limits and to provide constant supply of steam during power demand variations. Current feedwater control systems are often found to be unsatisfactory during startup and low power operations. A robust nonlinear estimator-based optimal algebraic control is developed for feedwater control systems to solve the water level tracking problem during power demand variations. It is shown that the proposed control provides an optimal and robust water level tracking with a single automatic controller over the complete range of power operations in the presence of plant uncertainties …
Analysis Of Active Power Control Algorithms Of Variable Speed Wind Generators For Power System Frequency Stabilization,
2016
TÜBİTAK
Analysis Of Active Power Control Algorithms Of Variable Speed Wind Generators For Power System Frequency Stabilization, Jakub Osmic, Mirza Kusljugic, Elvisa Becirovic, Daniel Toal
Turkish Journal of Electrical Engineering and Computer Sciences
A modified control algorithm of a variable speed wind generator (VSWG) for supporting power system frequency stabilization is presented in this paper. A comparison of the performance of this algorithm with active power control algorithms of VSWGs for supporting power system frequency stabilization, as published in the scientific literature, is also presented. A systematic method of analysis of the modified control algorithm is described in detail. It has been shown that by using the modified control algorithm, the VSWG ''truly'' emulates the inertial response of a conventional steam-generating unit with synchronous generators during the initial/inertial phase of primary frequency control, …
A Gis-Based Novel Active Monitoring System For Fiber Networks,
2016
TÜBİTAK
A Gis-Based Novel Active Monitoring System For Fiber Networks, Özer Koray Akdemi̇r, Taner Dursun, Sadik Arslan, Recep Benzer, Muhammet Ali̇ Akcayol
Turkish Journal of Electrical Engineering and Computer Sciences
In this study, a geographic information system (GIS)-based novel fiber network monitoring system has been developed to improve the operation and maintenance of fiber optic networks (FONs). The main aim of the developed system is to provide the required capabilities for both detailed digital modeling and central monitoring of FONs. The system can perform scheduled measurements and dispatch alarms if any fault or degradation is detected in the concerned FON. It also indicates the alarm locations on a map as a considerable contribution to decreasing mean time to repair. The developed monitoring system has more security features than others.
Modeling Based On 3d Finite Element Analysis And Experimental Study Of A 24-Slot 8-Pole Axial-Flux Permanent-Magnet Synchronous Motor For No Cogging Torque And Sinusoidal Back-Emf, Mehmet Güleç, Ersi̇n Yolaçan, Yücel Demi̇r, Oğuzhan Ocak, Meti̇n Aydin
Turkish Journal of Electrical Engineering and Computer Sciences
This paper discusses cogging torque minimization techniques in surface-mounted, axial-flux, multirotor permanent magnet synchronous disc motors in order to eliminate cogging components and obtain sinusoidal back-EMF for low-speed applications. Cogging torque minimization techniques are examined in detail with a focus on magnet skewing and pole and rotor shifting in order to obtain zero cogging. Some magnet shape and rotor design alternatives with conventional skew planar magnets were investigated based on 3D finite element analysis (FEA). Improvements compared to unskewed reference axial-flux permanent magnet (AFPM) motor design are presented. A prototype AFPM motor was built and tested based on the analyses. …
Heuristic Sample Reduction Method For Support Vector Data Description,
2016
TÜBİTAK
Heuristic Sample Reduction Method For Support Vector Data Description, Wenzhu Sun, Jianling Qu, Yang Chen, Yazhou Di, Feng Gao
Turkish Journal of Electrical Engineering and Computer Sciences
Support vector data description (SVDD) has become one of the most promising methods for one-class classification for finding the boundary of the training set. However, SVDD has a time complexity of $O\;(N^{3})$ and a space complexity of $O\;(N^{2})$. When dealing with very large sizes of training sets, e.g., a training set of the aeroengine gas path parameters with the size of $N>10^{6}$ sampled from several months of flight data, SVDD fails. To solve this problem, a method called heuristic sample reduction (HSR) is proposed for obtaining a reduced training set that is manageable for SVDD. HSR maintains the classification …
The Classification Of Eeg Signals Using Discretization-Based Entropy And The Adaptive Neuro-Fuzzy Inference System,
2016
TÜBİTAK
The Classification Of Eeg Signals Using Discretization-Based Entropy And The Adaptive Neuro-Fuzzy Inference System, Mahmut Heki̇m
Turkish Journal of Electrical Engineering and Computer Sciences
A novel feature extraction called discretization-based entropy is proposed for use in the classification of EEG signals. To this end, EEG signals are decomposed into frequency subbands using the discrete wavelet transform (DWT), the coefficients of these subbands are discretized into the desired number of intervals using the discretization method, the entropy values of the discretized subbands are calculated using the Shannon entropy method, and these are then used as the inputs of the adaptive neuro-fuzzy inference system (ANFIS). The equal width discretization (EWD) and equal frequency discretization (EFD) methods are used for the discretization. In order to evaluate their …
A Comprehensive Comparison Of Features And Embedding Methods For Face Recognition,
2016
TÜBİTAK
A Comprehensive Comparison Of Features And Embedding Methods For Face Recognition, Hasan Serhan Yavuz, Hakan Çevi̇kalp, Ri̇fat Edi̇zkan
Turkish Journal of Electrical Engineering and Computer Sciences
Face recognition is an essential issue in modern-day applications since it can be used in many areas for several purposes. Many methods have been proposed for face recognition. It is a difficult task since variations in lighting, instantaneous mimic varieties, posing angles, and scaling differences can drastically change the appearance of the face. To suppress these complications, effective feature extraction and proper alignment of face images gain as much importance as the recognition method choice. In this paper, we provide an extensive comparison of the state-of-the-art face recognition methods with the most well-known techniques used in feature representation. In order …
Kernel Fisher Discriminant Analysis Of Gabor Features For Online Palmprint Verification,
2016
TÜBİTAK
Kernel Fisher Discriminant Analysis Of Gabor Features For Online Palmprint Verification, Murat Eki̇nci̇, Murat Aykut
Turkish Journal of Electrical Engineering and Computer Sciences
We propose an online palmprint identification and verification algorithm with the use of kernel Fisher discriminant analysis (KFD) on the Gabor wavelet representation of palm images. Desirable palm features are derived by Gabor wavelets on the palm region. The KFD method is then employed to extract higher order relations among the Gabor-palm images for palmprint recognition. As a real-world application, the proposed algorithm was adapted into a novel online palmprint verification system that was employed in a student laboratory for 3 months. The feasibility of the Gabor-based KFD method was successfully tested on our proposed online palmprint system and on …
Linear Model Of A Three-Phase Shunt Active Power Filter With A Hysteresis Controller,
2016
TÜBİTAK
Linear Model Of A Three-Phase Shunt Active Power Filter With A Hysteresis Controller, Kadi̇r Vardar, Eyup Akpinar
Turkish Journal of Electrical Engineering and Computer Sciences
In this work, a linear model of a 3-phase active power filter (APF) is obtained to design a DC link proportional--integral (PI) controller. The system is designed on the basis of a TMS320F2812 digital signal processer (DSP). The PI controller is implemented in the program of the DSP. The hysteresis controller and sampling frequency are also taken into account in the linear model. The effect of hysteresis bandwidth, filter inductance, DC link capacitor, and sampling frequency on the stability are investigated by using the Routh--Hurwitz method. The detailed simulation model in MATLAB and experimental results showed that the linear model …
A Sparsity-Preserving Spectral Preconditioner For Power Flow Analysis,
2016
TÜBİTAK
A Sparsity-Preserving Spectral Preconditioner For Power Flow Analysis, Emrullah Fati̇h Yetki̇n, Hasan Dağ
Turkish Journal of Electrical Engineering and Computer Sciences
Due to the ever-increasing demand for more detailed and accurate power system simulations, the dimensions of mathematical models increase. Although the traditional direct linear equation solvers based on LU factorization are robust, they have limited scalability on the parallel platforms. On the other hand, simulations of the power system events need to be performed at a reasonable time to assess the results of the unwanted events and to take the necessary remedial actions. Hence, to obtain faster solutions for more detailed models, parallel platforms should be used. To this end, direct solvers can be replaced by Krylov subspace methods (conjugate …
A Switchable Approach To Large Object Allocation In Real-Time Java,
2016
TÜBİTAK
A Switchable Approach To Large Object Allocation In Real-Time Java, Veysel Harun Şahi̇n, Ümi̇t Kocabiçak
Turkish Journal of Electrical Engineering and Computer Sciences
Over the last 20 years object-oriented programming languages and managed run-times like Java have been very popular because of their software engineering benefits. Despite their popularity in many application areas, they have not been considered suitable for real-time programming. Besides many other factors, one of the barriers that prevent their acceptance in the development of real-time systems is the long pause times that may arise during large object allocation. This paper examines different kinds of solutions that have been developed so far and introduces a switchable approach to large object allocation in real-time Java. A synthetic benchmark application that is …
Improving The Srf Method To Compensate Low-Order Harmonics Under Nonsinusoidal Network Voltages,
2016
TÜBİTAK
Improving The Srf Method To Compensate Low-Order Harmonics Under Nonsinusoidal Network Voltages, Javad Modarresi, Mehdi Fallah, Eskandar Ghokipour, Mohammad Tavakoli Bina
Turkish Journal of Electrical Engineering and Computer Sciences
Increasing the application of power in electronic devices has increased the harmonics in power systems. Numerous methods like the synchronous reference frame (SRF) and the p-q-based method have been suggested to overcome the effects of these harmonics. The conventional SRF method provides acceptable results in harmonic compensation of high-order harmonics (higher than the fourth order), but the transient response time will be drastically increased in the presence of low-order harmonics due to the existence of a conventional low-pass filter. Furthermore, if the load terminal voltages are distorted, then the conventional SRF method will become unable to implement load current compensation. …
Relay Coordination Analysis And Protection Solutions For Smart Grid Distribution Systems,
2016
TÜBİTAK
Relay Coordination Analysis And Protection Solutions For Smart Grid Distribution Systems, Mehmet Tan Turan, Erdi̇n Gökalp
Turkish Journal of Electrical Engineering and Computer Sciences
Growing complexity of conventional power grids and their management, increasing power demand and energy quality expectations considering grid reliability, and efficiency and security concerns have triggered the evolution of smart grids. This is an expected result of implementing new technologies in existing grids, including renewable sources such as wind turbines and photovoltaic modules. With implementation of such new elements to the system, the protection concept should be considered by system regulators. In order to analyze protection problems, simulation-based analysis should be carried out before high-cost experimental studies. In this study, a simulation-based evaluation for a smart grid-based distribution system is …
