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2016

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Articles 1261 - 1290 of 1427

Full-Text Articles in Computer Engineering

Effect Of Load Increase And Power System Stabilizer On Stability Delay Margin Of A Generator Excitation Control System, Şahi̇n Sönmez, Saffet Ayasun Jan 2016

Effect Of Load Increase And Power System Stabilizer On Stability Delay Margin Of A Generator Excitation Control System, Şahi̇n Sönmez, Saffet Ayasun

Turkish Journal of Electrical Engineering and Computer Sciences

This paper studies the impact of load increase and a power system stabilizer (PSS) on the stability delay margin of a single-machine-infinite-bus system including an automatic voltage regulator. An analytical method is proposed to determine the stability delay margin of the excitation control system. The proposed method first eliminates transcendental terms in the characteristic equation of the excitation system without making any approximation and transforms the transcendental characteristic equation into a regular polynomial. The key result of the elimination process is that the real roots of the new polynomial correspond to the imaginary roots of the transcendental characteristic equation. With …

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Video Temporal Error Concealment Using Improved Directional Boundary Matching Algorithm, Seyed Mojtaba Marvasti-Zadeh, Hossein Ghanei-Yakhdan Jan 2016

Video Temporal Error Concealment Using Improved Directional Boundary Matching Algorithm, Seyed Mojtaba Marvasti-Zadeh, Hossein Ghanei-Yakhdan

Turkish Journal of Electrical Engineering and Computer Sciences

Nowadays some systems such as multimedia systems try to present a high quality of digital videos every day. Because of the possible errors in communication channels, compressed video data would be damaged in the sending process. Error concealment is a useful technique for concealing the effects of sending errors at the decoder. In this paper, an improved directional boundary matching algorithm is presented, in which by using adjacent macroblocks (MBs) of the damaged MB a direction is identified for each boundary. Then every boundary of candidate MBs is compared to an identified direction. Finally, the candidate motion vector (MV) that …

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Thermal Aging Of Solid Insulation Under Dual Temperature Variation, Amit Kumar Mehta, Ram Naresh Sharma, Sushil Chauhan Jan 2016

Thermal Aging Of Solid Insulation Under Dual Temperature Variation, Amit Kumar Mehta, Ram Naresh Sharma, Sushil Chauhan

Turkish Journal of Electrical Engineering and Computer Sciences

The power transformer is one of the most expensive pieces of equipment in a high-voltage AC power system. An adequate monitoring system for power transformers can help in reducing the failure rate and thereby enhance system reliability and economic efficiency. Long-term and accelerated aging is not possible in real transformers, so prorated models of real transformers are preferred. This paper presents a study aimed at the aging of different cellulose papers and pressboards impregnated with transformer oil subjected to accelerated thermal aging at an oil temperature of 120 $^{\circ}$C and winding temperature of 150 $^{\circ}$C for time intervals extending from …

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An Optimized Embedded Adder For Digital Signal Processing Applications, Kala Bharathan, Seshasayanan Ramachandran Jan 2016

An Optimized Embedded Adder For Digital Signal Processing Applications, Kala Bharathan, Seshasayanan Ramachandran

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, an embedded logic full adder (PRO-FA) circuit in transistor level is proposed that reduces logic complexity, consumes low power, and is low area. The design is implemented for 1 bit and then is further extended to 64 bits. The area obtained for 1-bit PRO-FA is 2.85 $ {\mu }{m}^{{2}}$ and is built using only 13 transistors. The PDP of the proposed adder is ${459.4\times }{{10}}^{{-18}} Ws $ and ADP is 128.25 $\mu {m}^{{2}}ps $ and is compared with the earlier reported designs. Furthermore, a 16-, 32-, 64-bit both linear and square-root carry select adder/subtractor (CSLAS) structure is …

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Dynamic Characteristics Of An Isolated Self-Excited Synchronous Reluctance Generator Driven By A Wind Turbine, Mosaad Mohiedden Ali, Said Mahmoud Allam, Talaat Hamdan Abdel-Moneim Jan 2016

Dynamic Characteristics Of An Isolated Self-Excited Synchronous Reluctance Generator Driven By A Wind Turbine, Mosaad Mohiedden Ali, Said Mahmoud Allam, Talaat Hamdan Abdel-Moneim

Turkish Journal of Electrical Engineering and Computer Sciences

This paper studies the dynamic characteristics of an isolated three-phase self-excited synchronous reluctance generator (SESRG) driven by a variable-speed wind turbine under different operating conditions. Self-excitation is achieved via capacitors connected across the generator terminals. A detailed mathematical modeling of the proposed self-excited wind generation system is presented. The proposed analysis is based on the dynamic qd-axis model of the SESRG. Magnetic saturation is taken into account and is assumed to be confined to the direct axis and is accounted for as a variable direct-axis magnetizing reactance. Effect of wind-speed variation, excitation-capacitance variation, and loading-conditions variation on the generated output …

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Low Leakage Power Gating Technique For Subnanometer Cmos Circuits, Kavitha Manickam, Govindaraj Thangavel Jan 2016

Low Leakage Power Gating Technique For Subnanometer Cmos Circuits, Kavitha Manickam, Govindaraj Thangavel

Turkish Journal of Electrical Engineering and Computer Sciences

Static power has become the most important factor in the fabrication of integrated circuits. Power gating techniques minimize leakage currents and help to develop ultra-low-power and high-performance digital circuits. In this paper, a power gating approach is proposed to minimize leakage for subnanometer technologies. Simulation results reveal that the proposed technique reduces maximum of 96% leakage power, 33% dynamic power, 49% drowsy power, and 16{\%} energy as compared to conventional techniques. The proposed technique offers good leakage reduction, even under variation of different operating parameters.

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The Parallel Resonance Impedance Detection Method For Parameter Estimation Of Power Line And Transformer By Using Csa, Ga, And Pso, Bahadir Akbal, Abdullah Ürkmez Jan 2016

The Parallel Resonance Impedance Detection Method For Parameter Estimation Of Power Line And Transformer By Using Csa, Ga, And Pso, Bahadir Akbal, Abdullah Ürkmez

Turkish Journal of Electrical Engineering and Computer Sciences

Power line parameters are an important factor in relay applications and power quality studies. In the literature, the phasor measurement unit method and measuring of current and voltage at two ends of the power line were usually used to estimate the power line parameters. In this study, the parallel resonance impedance detection method was used to estimate the power line parameter to obtain input data. The real measurement values are used to obtain parallel resonance impedance in this method. The real measurement values include the measurement errors of the current and voltage transformer. Thus, the estimated parameter values are realistic. …

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A New Method To Reduce The Adverse Effects Of Wind Power On Power Quality Using Reactive Power Compensating Capacitors, Seyed Navid Zahedi, Amir Amini, Hamid Falaghi Jan 2016

A New Method To Reduce The Adverse Effects Of Wind Power On Power Quality Using Reactive Power Compensating Capacitors, Seyed Navid Zahedi, Amir Amini, Hamid Falaghi

Turkish Journal of Electrical Engineering and Computer Sciences

The usage of distributed generation resources, particularly distributed generation with renewable sources, has increased to generate electrical power close to consumers. One of the factors that can reduce penetration of distributed generation resources is the limitation of power quality, such as harmonic distortions. Distributed generation sources, in addition to producing power, due to using of power electronic converters and changing the power flow, increase harmonic currents. On the other hand, local compensation of reactive power by parallel capacitor banks is one of the effective methods to reduce power system losses and harmonic distortions. Since the capacitor impedance varies at different …

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Investigation Of The Most Appropriate Mother Wavelet For Characterizing Imaginary Eeg Signals Used In Bci Systems, Önder Aydemi̇r, Temel Kayikçioğlu Jan 2016

Investigation Of The Most Appropriate Mother Wavelet For Characterizing Imaginary Eeg Signals Used In Bci Systems, Önder Aydemi̇r, Temel Kayikçioğlu

Turkish Journal of Electrical Engineering and Computer Sciences

Feature extraction is a very challenging task, since choosing discriminative features directly affects the recognition rate of the brain--computer interface (BCI) system. The objective of this paper is to investigate the effect of mother wavelets (MWs) on classification results. To this end, features were extracted from 3 different datasets using 12 MWs, and then the signals were classified using 3 classification algorithms, including k-nearest neighbor, support vector machine, and linear discriminant analysis. The experiments proved that Daubechies and Shannon were the most suitable wavelet families for extracting more discriminative features from imaginary EEG/ECoG signals.

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Noise Adjusted Version Of Generalized Principal Component Analysis, Mojtaba Amini-Omam, Farah Torkamani Azar Jan 2016

Noise Adjusted Version Of Generalized Principal Component Analysis, Mojtaba Amini-Omam, Farah Torkamani Azar

Turkish Journal of Electrical Engineering and Computer Sciences

Principal component analysis (PCA) is a well-known tool in image processing, especially in dimension reduction schemes. Since using PCA is based on the vector representation of the image, the spatial locality of pixels in the image is not considered. However, generalized PCA (GPCA) could be applied to images in two dimensional spaces. Both schemes do not consider the noisy case of signals. Noise adjusted PCA (NAPCA) tries to find new coordinates for signal representation based on signal to noise ratio (SNR) maximization. In this paper we generalized noise adjusted GPCA to benefit the advantage of GPCA and SNR maximization case …

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Stochastic Congestion Management Considering Power System Uncertainties: A Chance-Constrained Programming Approach, Mehrdad Hojjat, Mohammad Hossein Javidi, Dariush Yazdanpanah Jan 2016

Stochastic Congestion Management Considering Power System Uncertainties: A Chance-Constrained Programming Approach, Mehrdad Hojjat, Mohammad Hossein Javidi, Dariush Yazdanpanah

Turkish Journal of Electrical Engineering and Computer Sciences

Considering system uncertainties in developing power systems, algorithms such as congestion management (CM) are vital in power system analysis and studies. This paper proposes a new model for power system CM by considering power system uncertainties based on chance-constrained programming (CCP). In the proposed approach, transmission constraints are taken into account by stochastic, instead of deterministic, models. The proposed approach considers network uncertainties with a specific level of probability in the optimization process, and then an analytical approach is used to solve the new model of stochastic congestion management. In this approach, the stochastic optimization problem is transformed into an …

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Highly Efficient Three-Phase Three-Level Multilevel Inverter Employing Different Commutation Strategies, Ammar Masaoud, Hew Wooi Ping, Saad Mekhilef, Hamza Belkamel Jan 2016

Highly Efficient Three-Phase Three-Level Multilevel Inverter Employing Different Commutation Strategies, Ammar Masaoud, Hew Wooi Ping, Saad Mekhilef, Hamza Belkamel

Turkish Journal of Electrical Engineering and Computer Sciences

This paper introduces a new three-phase three-level voltage source inverter. The proposed topology constitutes the conventional three-phase two-level inverter with three bidirectional switches. For purpose of generating the appropriate switching gate signals, two different commutation strategies are suggested and analyzed. A comparison between both strategies in terms of power losses and efficiency are presented. To ensure the feasibility of the proposed configuration with its suggested commutation strategies, the prototype of the proposed inverter was manufactured and the experimental results are given.

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Estimating And Reshaping Human Intention Via Human--Robot Interaction, Aki̇f Durdu, İsmet Erkmen, Aydan Müşerref Erkmen Jan 2016

Estimating And Reshaping Human Intention Via Human--Robot Interaction, Aki̇f Durdu, İsmet Erkmen, Aydan Müşerref Erkmen

Turkish Journal of Electrical Engineering and Computer Sciences

Human--robot interaction (HRI) is studied in two important research areas, intention estimation and intention reshaping. Although there are many studies in the literature that define human intention, new research examines the reshaping of human intentions by using robots in HRI. In this paper, 2 different robot movements are tested in a real environment in order to reshape current human intention. The hidden Markov model (HMM) is used to estimate human intention in our intelligent robotic system. The algorithmic design of the system comprises 2 parts: the first part tracks the moving objects in the environment, and the second part estimates …

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Papr Reduction Using Genetic Algorithm In Lifting-Based Wavelet Packet Modulation Systems, Necmi̇ Taşpinar, Yüksel Tokur Bozkurt Jan 2016

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 …

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Behavior Learning Of A Memristor-Based Chaotic Circuit By Extreme Learning Machines, Ayşegül Uçar, Emrehan Yavşan Jan 2016

Behavior Learning Of A Memristor-Based Chaotic Circuit By Extreme Learning Machines, Ayşegül Uçar, Emrehan Yavşan

Turkish Journal of Electrical Engineering and Computer Sciences

As the behavior of a chaotic Chua's circuit is nonstationary and inherently noisy, it is regarded as one of the most challenging applications. One of the fundamental problems in the prediction of the behavior of a chaotic Chua's circuit is to model the circuit with high accuracy. The current paper presents a novel method based on multiple extreme learning machine (ELM) models to learn the chaotic behavior of the four elements canonical Chua's circuit containing a memristor instead of a nonlinear resistor only by using the state variables as the input. In the proposed method four ELM models are used …

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Rlc Circuit Extraction With The Differential Evolution Algorithm For Conducted Electromagnetic Emission Model Of Integrated Circuits, Muhammed Emi̇n Başak, Ayten Kuntman Jan 2016

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 …

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A Gis-Based Novel Active Monitoring System For Fiber Networks, Özer Koray Akdemi̇r, Taner Dursun, Sadik Arslan, Recep Benzer, Muhammet Ali̇ Akcayol Jan 2016

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.

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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 Jan 2016

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. …

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A New Algorithm Of Parameter Estimation Of A Photovoltaic Solar Panel, Mustapha Belarbi, Kamel Haddouche, El-Habib Belarbi, Amine Boudghene-Stambouli Jan 2016

A New Algorithm Of Parameter Estimation Of A Photovoltaic Solar Panel, Mustapha Belarbi, Kamel Haddouche, El-Habib Belarbi, Amine Boudghene-Stambouli

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, we present a new approach for estimating the one-diode model parameters of a photovoltaic solar panel according to the irradiance and temperature. These parameters are given, at a known irradiance and temperature, from the knowledge of three operating points: short circuit, open circuit, and maximum power. In the first step, the adopted approach concerns the resolution of the system of equations constituting the three operating points to write all the model parameters according to series resistance. Secondly, we make an iterative resolution at the optimal operating point by using the Newton--Raphson method to calculate the series resistance …

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The Classification Of Eeg Signals Using Discretization-Based Entropy And The Adaptive Neuro-Fuzzy Inference System, Mahmut Heki̇m Jan 2016

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 …

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Heuristic Sample Reduction Method For Support Vector Data Description, Wenzhu Sun, Jianling Qu, Yang Chen, Yazhou Di, Feng Gao Jan 2016

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 …

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Amplitude-Phase Control Of A Novel Chaotic Attractor, Chunbiao Li, İhsan Pehli̇van, Julien Clinton Sprott Jan 2016

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 …

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Optimal Power Flow With Svc Devices By Using The Artificial Bee Colony Algorithm, Kadi̇r Abaci, Volkan Yamaçli, Ali̇ Akdağli Jan 2016

Optimal Power Flow With Svc Devices By Using The Artificial Bee Colony Algorithm, Kadi̇r Abaci, Volkan Yamaçli, Ali̇ Akdağli

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper a simple and efficient heuristic search method based on the artificial bee colony (ABC) algorithm is presented and used for the optimal power flow (OPF) problem in power systems with static VAR compensator (SVC) devices. The total generation cost of a power system with SVC devices (which improve the voltage stability at load buses) is optimally minimized with the use of ABC. The ABC, which is based on the foraging behavior of honey bees searching for the best food source, is a recently proposed optimization algorithm. The performance of the presented ABC algorithm was tested and verified …

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A Comprehensive Comparison Of Features And Embedding Methods For Face Recognition, Hasan Serhan Yavuz, Hakan Çevi̇kalp, Ri̇fat Edi̇zkan Jan 2016

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 …

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A Robust Estimator-Based Optimal Algebraic Approach To Steam Generator Feedwater Control System, Günyaz Ablay Jan 2016

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 …

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Kernel Fisher Discriminant Analysis Of Gabor Features For Online Palmprint Verification, Murat Eki̇nci̇, Murat Aykut Jan 2016

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 …

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Extracting The Region Of Interest From Mfl Signals, Ali Sadr, Raziyeh Sadat Okhovat Jan 2016

Extracting The Region Of Interest From Mfl Signals, Ali Sadr, Raziyeh Sadat Okhovat

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, we study the magnetic flux leakage (MFL) signals for detection of defects in ferromagnetic materials. MFL signals consist of a background that is not constant and is combined with noise. Since there are slight variations because of noise, any large distortion shows a defect. Here the estimation of the background and then the determination of a threshold to distinguish defects from noise have been used for locating defects. In this method, precise evaluation of these two parameters has a vital role on the defect detection. The concept of histograms has been employed for eliminating the effect of …

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A Sparsity-Preserving Spectral Preconditioner For Power Flow Analysis, Emrullah Fati̇h Yetki̇n, Hasan Dağ Jan 2016

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 …

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An Alternative Carry-Save Arithmetic For New Generation Field Programmable Gate Arrays, Uğur Çi̇ni̇, Mustafa Aktan, Avni̇ Morgül Jan 2016

An Alternative Carry-Save Arithmetic For New Generation Field Programmable Gate Arrays, Uğur Çi̇ni̇, Mustafa Aktan, Avni̇ Morgül

Turkish Journal of Electrical Engineering and Computer Sciences

In this work, a double carry-save addition operation is proposed, which is efficiently synthesized for 6-input LUT-based field programmable gate arrays (FPGAs). The proposed arithmetic operation is based on redundant number representation and provides carry propagation-free addition. Using the proposed arithmetic operation, a compact and fast multiply and accumulate unit is designed. To our knowledge, the proposed design provides the fastest multiply-add operation for 6-input LUT-based FPGA systems. A finite impulse response filter implementation is given to show the performance of the proposed structure. The proposed implementation provides a dramatic performance increase, which is at least 2 times faster than …

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Incremental Weighted Bipartite Algorithm For Large-Scale Recommendation Systems, Haihong E, Jianfeng Wang, Meina Song, Qiang Bi, Yingyi Liu Jan 2016

Incremental Weighted Bipartite Algorithm For Large-Scale Recommendation Systems, Haihong E, Jianfeng Wang, Meina Song, Qiang Bi, Yingyi Liu

Turkish Journal of Electrical Engineering and Computer Sciences

Personalized recommendation systems are a solution for information overload. In the real recommendation system, the data are dynamic; thus, the real time of the system will be seriously affected if we recalculate after every change, and, in time, sensitive situation of the delayed updated calculation will affect the accuracy of the recommendation. The incremental calculation methods of collaborative filtering, clustering, singular value decomposition, and bipartite algorithm have achieved some progress; however, there is limited research on the incremental computation of the weighted bipartite algorithm. This paper proposes a personalized recommendation algorithm. In this algorithm, the rank of the recommendations is …

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