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Articles 3091 - 3120 of 5278

Full-Text Articles in Computer Sciences

Computation Of The Scattered Fields From An Arbitrary Discontinuity On A Perfectly Conducting Ground Plane By A Decomposition Method, Ahmet Kizilay, Uğur Saynak Jan 2016

Computation Of The Scattered Fields From An Arbitrary Discontinuity On A Perfectly Conducting Ground Plane By A Decomposition Method, Ahmet Kizilay, Uğur Saynak

Turkish Journal of Electrical Engineering and Computer Sciences

A novel procedure for solving plane wave incident on arbitrary bump or cavity geometries on a perfectly conducting ground plane is introduced. The method is presented with examples for transverse-magnetic polarization compared to various other solution methods. The proposed method can be easily generalized to other similar problems.


A New Fuzzy Membership Assignment And Model Selection Approach Based On Dynamic Class Centers For Fuzzy Svm Family Using The Firefly Algorithm, Omid Naghash Almasi, Modjtaba Rouhani Jan 2016

A New Fuzzy Membership Assignment And Model Selection Approach Based On Dynamic Class Centers For Fuzzy Svm Family Using The Firefly Algorithm, Omid Naghash Almasi, Modjtaba Rouhani

Turkish Journal of Electrical Engineering and Computer Sciences

The support vector machine (SVM) is a powerful tool for classification problems. Unfortunately, the training phase of the SVM is highly sensitive to noises in the training set. Noises are inevitable in real-world applications. To overcome this problem, the SVM was extended to a fuzzy SVM by assigning an appropriate fuzzy membership to each data point. However, suitable choice of fuzzy memberships and an accurate model selection raise fundamental issues. In this paper, we propose a new method based on optimization methods to simultaneously generate appropriate fuzzy membership and solve the model selection problem for the SVM family in linear/nonlinear …


Penalty Factor-Based Optimization Algorithm For Distributed Generation Sizing In Distribution Network, Jasrul Jamani Jamian, Mohd Nabil Bin Muhtazaruddin, Muhammad Ariff Baharuddin Jan 2016

Penalty Factor-Based Optimization Algorithm For Distributed Generation Sizing In Distribution Network, Jasrul Jamani Jamian, Mohd Nabil Bin Muhtazaruddin, Muhammad Ariff Baharuddin

Turkish Journal of Electrical Engineering and Computer Sciences

The installation of distributed generation (DG) can be used to minimize the total power loss in the distribution network. Besides that, other power system performances such as voltage profile, stability index, and total harmonic distortion can also be improved via DG. Although many works on DG have been done, most researchers have assumed that the distribution line is in an ideal condition (unlimited capacity limit). On the contrary, all practical lines should have their own capacity limit. Therefore, the main contribution of this paper is to determine the optimal DG output that can fulfill the maximum allowable line capacity limit …


System Identification By Using Migrating Birds Optimization Algorithm: A Comparative Performance Analysis, Hasan Makas, Nejat Yumuşak Jan 2016

System Identification By Using Migrating Birds Optimization Algorithm: A Comparative Performance Analysis, Hasan Makas, Nejat Yumuşak

Turkish Journal of Electrical Engineering and Computer Sciences

System identification is an important process to investigate and understand the behavior of an unknown system. It aims to establish an interface between the real system and its mathematical representation. Conventional system identification methods generally need differentiable search spaces and they cannot be used for nondifferentiable multimodal search spaces. On the other hand, metaheuristic search algorithms are independent from the search space characteristics and they do not need much knowledge about the real system. The migrating birds optimization algorithm is a recently introduced nature-inspired metaheuristic neighborhood search approach. It simulates the V flight formation of migrating birds, which enables birds …


Classification Of Short-Circuit Faults In High-Voltage Energy Transmission Line Using Energy Of Instantaneous Active Power Components-Based Common Vector Approach, Mehmet Yumurtaci, Gökhan Gökmen, Çağri Kocaman, Semi̇h Ergi̇n, Osman Kiliç Jan 2016

Classification Of Short-Circuit Faults In High-Voltage Energy Transmission Line Using Energy Of Instantaneous Active Power Components-Based Common Vector Approach, Mehmet Yumurtaci, Gökhan Gökmen, Çağri Kocaman, Semi̇h Ergi̇n, Osman Kiliç

Turkish Journal of Electrical Engineering and Computer Sciences

The majority of power system faults occur in transmission lines. The classification of these faults in power systems is an important issue. In this paper, the real parameters of a 28 km, 154 kV transmission line between Simav and Demirci in Turkey's electricity transmission network is simulated in MATLAB/Simulink. Wavelet packet transform (WPT) is applied to instantaneous voltage signals. Instantaneous active power components are obtained by multiplying instantaneous currents obtained from a voltage source side with these WPT-based voltage signal components. A new feature vector extraction scheme is employed by calculating the energies of instantaneous active power components. Constructed feature …


Some Properties Of Digital H-Spaces, Özgür Ege, İsmet Karaca Jan 2016

Some Properties Of Digital H-Spaces, Özgür Ege, İsmet Karaca

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, we study certain properties of digital H-spaces. We prove that a digital image that has the same digital homotopy type with any digital H-space is also a digital H-space. We show that the digital fundamental group of a digital H-space is abelian. We give examples that are related to a digital homotopy associative H-space and a $\kappa $-contractible digital H-space. Several important applications of digital H-spaces are given in computer vision and image processing. Finally, we deal with the importance of digital H-space in digital topology and image processing. We conclude that any $\kappa $-contractible digital image …


Performance Evaluation Of A New Efficient H.264 Intraprediction Scheme, Sara Hamdy, Mostafa Ibrahim, Mohamed Osman Jan 2016

Performance Evaluation Of A New Efficient H.264 Intraprediction Scheme, Sara Hamdy, Mostafa Ibrahim, Mohamed Osman

Turkish Journal of Electrical Engineering and Computer Sciences

The paper presents a new efficient H.264/AVC$ 4 \times 4$ intraprediction scheme. The new prediction scheme is based on the best prediction matrix mode. The main idea behind the new prediction scheme is to combine the most usable intraprediction modes, {vertical - horizontal - DC} , into a new efficient prediction mode. The new prediction scheme is implemented using VHDL and hence it uses the full advantages of inherent parallelism in the hardware. We evaluate the performance of this prediction scheme in terms of compression ratio, peak signal to noise ratio, and bit rate using seven video sequences. Moreover, we …


Identifying Acquisition Devices From Recorded Speech Signals Using Wavelet-Based Features, Ömer Eski̇dere Jan 2016

Identifying Acquisition Devices From Recorded Speech Signals Using Wavelet-Based Features, Ömer Eski̇dere

Turkish Journal of Electrical Engineering and Computer Sciences

Speech characteristics have played a critical role in media forensics, particularly in the investigation of evidence. This study proposes two wavelet-based feature extraction methods for the identification of acquisition devices from recorded speech. These methods are discrete wavelet-based coefficients (DWBCs) and wavelet packet-based coefficients, which are mainly based on a multiresolution analysis. These features' ability to capture characteristics of acquisition devices is compared to conventional mel frequency cepstral coefficients and subband-based coefficients. In the experiments, 14 different audio acquisition devices were trained and tested using support vector machines. Experimental results showed that DWBCs can effectively be used in source audio …


A Slotted Aloha-Based Cognitive Radio Network Under Capture Effect In Rayleigh Fading Channels, Muhammed Enes Bayrakdar, Sedat Atmaca, Alper Karahan Jan 2016

A Slotted Aloha-Based Cognitive Radio Network Under Capture Effect In Rayleigh Fading Channels, Muhammed Enes Bayrakdar, Sedat Atmaca, Alper Karahan

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, a slotted ALOHA-based cognitive radio (CR) network is proposed and the throughput performance of the proposed CR network model under Rayleigh fading channels is examined. Our CR network contains two special groups of users, primary users (PUs) and CR users (CRUs), and they are considered to be sharing a time-slotted-based common communication channel. While PUs can access the channel at any time owing to their legal right, CRUs can only access the channel when it is not occupied by the PUs. In the network model developed, PUs access the channel utilizing time division multiple access as a …


Application Of Kappa Statistics In Sequential Tests For Family-Based Design, Farid Rajabli Jan 2016

Application Of Kappa Statistics In Sequential Tests For Family-Based Design, Farid Rajabli

Turkish Journal of Electrical Engineering and Computer Sciences

Family-based designs are commonly used in genetic association studies to locate markers associated with diseases. It is a challenging task to collect a large enough sample size, perform a statistical test, and obtain the desired statistical power. The sequential probability ratio test (SPRT) was introduced to overcome the limited sample size problem. However, the drawback of SPRT is that, for the sake of accuracy, the test leaves many markers in a gray zone meaning ``no decision''. In this article, we propose a novel approach: a sequential probability ratio test `plus' (SPRT$+)$ to reduce the number of these gray zone markers. …


Vehicle Localization Systems: Towards Low-Cost Architectures, Sakhi Samir, Abdelhafid Elouardi, Bouaziz Samir, Mahmoud Belhocine Jan 2016

Vehicle Localization Systems: Towards Low-Cost Architectures, Sakhi Samir, Abdelhafid Elouardi, Bouaziz Samir, Mahmoud Belhocine

Turkish Journal of Electrical Engineering and Computer Sciences

the accuracy of an inertial navigation system alone. However, its implementation complexity has been a challenge to most embedded systems. This paper proposes a low-cost FPGA-based INS-GPS integration system, which consists of a Kalman filter and a soft processor. Moreover, we also evaluate the navigation algorithm on a low-cost ARM processor. Processing times and localization accuracy are compared in both cases for single and double precision floating-point format. Experimental results show the advantages of the FPGA-based approach over the ARM-based approach. The proposed architecture can operate at 100 Hz and demonstrates the advantage of using FPGAs to design low-cost INS-GPS …


Design Of A Frequency Control System In A Microgrid Containing Hvac, Mohammad Koochakian Jazi, Seyed Masoud Moghaddas-Tafreshi, Mehdi Jafari Jan 2016

Design Of A Frequency Control System In A Microgrid Containing Hvac, Mohammad Koochakian Jazi, Seyed Masoud Moghaddas-Tafreshi, Mehdi Jafari

Turkish Journal of Electrical Engineering and Computer Sciences

controllable loads and tending to the demand response (DR) in small power systems have helped with new ideas, which can be used in the frequency stability of a microgrid. This paper presents a novel model for frequency control of a microgrid containing controllable load and renewable resources. The controllable loads used in this paper are such as heating, ventilation, and air conditioning, which change temperature based on frequency change. The microgrid is hybrid (AC/DC) and able to connect to and energy exchange with the utility grid. The design of PID controller parameters is considered an optimization problem according to the …


Three-Phase Multilevel Inverter With High Value Of Resolution Per Switch Employing A Space Vector Modulation Control Scheme, Md Mubashwar Hasan, Saad Mekhilef, Mahrous Ahmed, Tarek Messikh Jan 2016

Three-Phase Multilevel Inverter With High Value Of Resolution Per Switch Employing A Space Vector Modulation Control Scheme, Md Mubashwar Hasan, Saad Mekhilef, Mahrous Ahmed, Tarek Messikh

Turkish Journal of Electrical Engineering and Computer Sciences

inverter is presented in this paper. This configuration cancels the redundancy of output voltage steps and maximizes the number of levels in the output voltage. This structure is built by using series connected stages, which minimize the number of semiconductor switches, gate drive arrangements, occupying area, and cost. It is a modular type inverter model and the number of voltage levels can be increased by adding new stages without changing the previous connection. Space vector modulation has been applied as the control strategy. A prototype of the proposed inverter topology has been built in the laboratory. The attached hardware results …


A New Algorithm For Detection Of Link Spam Contributed By Zero-Out Link Pages, Ravi Kumar Patchmuthu, Ashutosh Kumar Singh, Anand Mohan Jan 2016

A New Algorithm For Detection Of Link Spam Contributed By Zero-Out Link Pages, Ravi Kumar Patchmuthu, Ashutosh Kumar Singh, Anand Mohan

Turkish Journal of Electrical Engineering and Computer Sciences

No abstract provided.


Enhancement Of A Reduced Order Doubly Fed Induction Generator Model For Wind Farm Transient Stability Analyses, Mehmet Kenan Döşoğlu, Ayşen Basa Arsoy Jan 2016

Enhancement Of A Reduced Order Doubly Fed Induction Generator Model For Wind Farm Transient Stability Analyses, Mehmet Kenan Döşoğlu, Ayşen Basa Arsoy

Turkish Journal of Electrical Engineering and Computer Sciences

(DFIG) implemented for wind power systems is very important for transient stability. The rotor dynamic model (RDM) as well as the reduced order model (ROM) of a DFIG has been developed for transient analysis purpose. The performances of reduced order DFIG models with/without RDM have been compared. Modeling and analyses have been carried out in MATLAB/SIMULINK. Comparison of system behaviors against 3 phase fault is made between without RDM and with RDM. Several parameters such as output voltage, active power, speed, electrical torque variations, and d-q axis stator and rotor current variations of the DFIG along with a 34.5 kV …


Plea: Parametric Loop Bound Estimation In Wcet Analysis, Saeed Parsa, Mehdi Sakhaei-Nia Jan 2016

Plea: Parametric Loop Bound Estimation In Wcet Analysis, Saeed Parsa, Mehdi Sakhaei-Nia

Turkish Journal of Electrical Engineering and Computer Sciences

No abstract provided.


Automatic Detection Of Coronary Artery Disease Using Registration Of Ultrasound Images Of The Heart (Echocardiography), Pedram Masaeli, Seyyed Mohammad Alavi Jan 2016

Automatic Detection Of Coronary Artery Disease Using Registration Of Ultrasound Images Of The Heart (Echocardiography), Pedram Masaeli, Seyyed Mohammad Alavi

Turkish Journal of Electrical Engineering and Computer Sciences

No abstract provided.


A New Method For Accurate Estimation Of Pv Module Parameters And Extraction Of Maximum Power Point Under Varying Environmental Conditions, Mohamed Saleem Abdul Kareem, Manimaran Saravanan Jan 2016

A New Method For Accurate Estimation Of Pv Module Parameters And Extraction Of Maximum Power Point Under Varying Environmental Conditions, Mohamed Saleem Abdul Kareem, Manimaran Saravanan

Turkish Journal of Electrical Engineering and Computer Sciences

The objective of this paper is to estimate the values of five parameters ($A$, $R_{se}$, $ R_{sh}$, $ I_{LG}$, and $I_{sat})$ of a PV module more accurately and to extract the maximum power point (MPP) accurately under varying environmental conditions. Suitable new equations are proposed, by which the values of the series and shunt resistances are initialized in order to obtain good convergence speed in the Gauss--Seidel method. In this work, two new equations are proposed to find the ideality factor and shunt resistance and to obtain accurate MPP of the PV model under varying environmental conditions. The proposed PV …


Modeling And Rotor Field-Oriented Control Of A Faulty Three-Phase Induction Motor Based On Gsa For Tuning Of Pi Controllers, Ali Monadi, Mohammad Jannati, Nik Rumizi Nik Idris, Ahmad Athif Mohd Faudzi, Frede Blaabjerg Jan 2016

Modeling And Rotor Field-Oriented Control Of A Faulty Three-Phase Induction Motor Based On Gsa For Tuning Of Pi Controllers, Ali Monadi, Mohammad Jannati, Nik Rumizi Nik Idris, Ahmad Athif Mohd Faudzi, Frede Blaabjerg

Turkish Journal of Electrical Engineering and Computer Sciences

modeling and a rotor field-oriented control (RFOC) system for controlling a faulty three-phase induction motor (three-phase IM when one of the phases is disconnected). In the adapted scheme for controlling the faulty IM, it is necessary for the PI controller coefficients to change. For this purpose, the gravitational search algorithm (GSA) is used for tuning of PI controllers. The results show the strength and ability of the technique to improve the performance of the faulty IM control.


Name Spell-Check Framework For Social Networks, Burak Yildiz, Fati̇h Emekci̇ Jan 2016

Name Spell-Check Framework For Social Networks, Burak Yildiz, Fati̇h Emekci̇

Turkish Journal of Electrical Engineering and Computer Sciences

No abstract provided.


Reducedcbt And Supercbt: Two New And Improved Complete Binary Tree Structures, Mevlüt Bulut Jan 2016

Reducedcbt And Supercbt: Two New And Improved Complete Binary Tree Structures, Mevlüt Bulut

Turkish Journal of Electrical Engineering and Computer Sciences

tree, a separate parent-child-sister hierarchy is employed independent of the parent-child-sister hierarchy used for the rest of the tree. Two different versions of such a local hierarchy are introduced. The result of the first proposed hierarchy is a faster and smaller footprint, while the second one provides size variation functionality without a significant computational overhead. Complexity comparison between the algorithms based on the introduced local hierarchies and ones based on previous complete binary tree structures reveals that the novel approach brings considerable memory gains and performance boosts to the complete binary tree based algorithms.


Design And Implementation Of A New Manet Simulator Model For Aodv Simulation, Si̇nan Tüncel, Hüseyi̇n Eki̇z, Ahmet Zengi̇n Jan 2016

Design And Implementation Of A New Manet Simulator Model For Aodv Simulation, Si̇nan Tüncel, Hüseyi̇n Eki̇z, Ahmet Zengi̇n

Turkish Journal of Electrical Engineering and Computer Sciences

No abstract provided.


A Real-Time Virtual Sculpting Application By Using An Optimized Hash-Based Octree, Gülüzar Çi̇t, Kayhan Ayar, Cemi̇l Öz Jan 2016

A Real-Time Virtual Sculpting Application By Using An Optimized Hash-Based Octree, Gülüzar Çi̇t, Kayhan Ayar, Cemi̇l Öz

Turkish Journal of Electrical Engineering and Computer Sciences

sculpting system by using a hash-based octree data structure with an optimized approach to reduce the huge memory and computation cost and also the tree traversal time. The system first reads the selected 3D virtual object model, which must be in a triangular watertight polygon mesh format. Then both the surface and the interior volume of the virtual object is voxelized in order to generate its volumetric dataset. Afterwards, a hash-based data structure with a novel optimized approach is applied to the dataset. After each sculpting process applied to the virtual object, its surface is locally reconstructed and a feedback …


Modeling And Control Of A 6-Control-Area Interconnected Power System To Protect The Network Frequency Applying Different Controllers, Ngockhoat Nguyen, Qi Huang, Thi-Mai-Phuong Dao Jan 2016

Modeling And Control Of A 6-Control-Area Interconnected Power System To Protect The Network Frequency Applying Different Controllers, Ngockhoat Nguyen, Qi Huang, Thi-Mai-Phuong Dao

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, we first analyze and build a model of the 6-control-area interconnected power system as the typical case study. Subsequently, different frequency controllers based on tie-line bias control strategy, namely integral, proportional--integral, proportional--integral--derivative, and PI-based fuzzy logic, will be investigated and applied to the power system model. The most important control performances, such as overshoots and settling times, are considered in this study to evaluate the stability of the power system and choose the most suitable controller for maintaining the network frequency. The simulation results have been achieved by using MATLAB/Simulink package version 2013 in this work. According …


Peak-To-Average Power Ratio Reduction Using Backtracking Search Optimization Algorithm In Ofdm Systems, Necmi̇ Taşpinar, Yüksel Tokur Bozkurt Jan 2016

Peak-To-Average Power Ratio Reduction Using Backtracking Search Optimization Algorithm In Ofdm Systems, Necmi̇ Taşpinar, Yüksel Tokur Bozkurt

Turkish Journal of Electrical Engineering and Computer Sciences

A peak-to-average power ratio (PAPR) reduction method for an orthogonal frequency division multiplexing (OFDM) system based on a combination of a partial transmit sequence (PTS) scheme with the backtracking search optimization algorithm (BSA) is proposed. The PTS scheme shows good PAPR reduction performance; however, it requires a complex computation to search the set of optimum phase factors, especially for high-speed data transmissions. To minimize the complexity of the search for optimum phase factors, the PTS scheme is combined with the BSA. The BSA is a new and efficient population-based evolutionary search algorithm for real-valued optimization problems. A set of simulations …


Ship-Radiated Noise Feature Extraction Using Multiple Kernel Graph Embedding And Auditory Model, Xinzhou Xu, Xinwei Luo, Chen Wu, Li Zhao Jan 2016

Ship-Radiated Noise Feature Extraction Using Multiple Kernel Graph Embedding And Auditory Model, Xinzhou Xu, Xinwei Luo, Chen Wu, Li Zhao

Turkish Journal of Electrical Engineering and Computer Sciences

No abstract provided.


Dynamic Analysis Of A Modular Isolated Bidirectional Dc-Dc Converter For High Power Applications, Farzad Sedaghati, Seyed Hossein Hosseini, Mehran Sabahi, Gevorg Babamalek Gharehpetian Jan 2016

Dynamic Analysis Of A Modular Isolated Bidirectional Dc-Dc Converter For High Power Applications, Farzad Sedaghati, Seyed Hossein Hosseini, Mehran Sabahi, Gevorg Babamalek Gharehpetian

Turkish Journal of Electrical Engineering and Computer Sciences

dc-dc converters is presented. The proposed converter has interesting features such as fewer switching devices, bidirectional power flow, and low switching losses. The simple modular structure, high frequency operation, zero voltage switching (ZVS) capability, and fewer switching devices make the extended configuration of the proposed converter suitable for high power applications. The operation principle of the proposed converter is analyzed in steady state, and then ZVS analysis of the converter is presented in detail. A generalized averaging technique, which uses dc and first order terms of Fourier's series of state variables, is applied to model the converter. A small-signal average …


Automated Separation Of Gray And White Matter In Brain Mris By Fastened Segments Of Geodesic Contours, Ali̇ İskurt Jan 2016

Automated Separation Of Gray And White Matter In Brain Mris By Fastened Segments Of Geodesic Contours, Ali̇ İskurt

Turkish Journal of Electrical Engineering and Computer Sciences

tissues in the brain separated by an interface. Extraction of this boundary is very important for quantitative analysis and monitoring of atrophy. A perfect capture for this purpose is a missing vital item for which research continues. In order to get close to such precision, two novel systems are presented for segmentation of cortical GM and WM in brain MRIs. The system imitates human perceptual sensitiveness to contrast, which is the basic principle of edge detection algorithms, and completes its shortcoming feature of segmentation. As well as being completely automatic, the system is also unsupervised. The correct GM-WM boundary rate …


An Adaptive Fuzzy Pi Controlled Bus Quantity Enhancer For Wave Energy Systems, Emre Özkop, Adel Sharaf, İsmai̇l Hakki Altaş Jan 2016

An Adaptive Fuzzy Pi Controlled Bus Quantity Enhancer For Wave Energy Systems, Emre Özkop, Adel Sharaf, İsmai̇l Hakki Altaş

Turkish Journal of Electrical Engineering and Computer Sciences

(AFPIC) for a flexible AC transmission system (FACTS)-based dynamic power filter (DPF) to be used in wave energy conversion systems. The new FACTS device stabilizes the DC-common bus voltage, reduces quality of power troubles, and enhances energy utilization by acting as a bus quantity enhancer (BQE). The design and realization of the proposed FACTS-based DPF and efficient control schemes are fully studied. To validate the efficiency of the proposed BQE FACTS device, a digital simulation model and a laboratory test system are developed in the MATLAB/Simulink/Simpower software environment for comparison. Various experimental test models of the proposed BQE system and …


A New Wideband Electronically Tunable Grounded Resistor Employing Only Three Mos Transistors, Erkan Yuce, Sezai̇ Tokat, Firat Yücel Jan 2016

A New Wideband Electronically Tunable Grounded Resistor Employing Only Three Mos Transistors, Erkan Yuce, Sezai̇ Tokat, Firat Yücel

Turkish Journal of Electrical Engineering and Computer Sciences

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