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Articles 15421 - 15450 of 25629

Full-Text Articles in Computer Engineering

High Photoresponse From Solution Processed Conventional And Inverted Ultraviolet Photodetectors, Görkem Memi̇şoğlu, Canan Varlikli Jan 2016

High Photoresponse From Solution Processed Conventional And Inverted Ultraviolet Photodetectors, Görkem Memi̇şoğlu, Canan Varlikli

Turkish Journal of Electrical Engineering and Computer Sciences

The optical and electrical properties of conventional and inverted type ultraviolet photodetectors (UVPDs) with active layers of poly(9,9-dioctylfluorenyl-2,7-ylenethynylene (PFE), $N$,$N'$-bis-$n$-butyl-1,4,5,8-naphthalenediimide (BNDI), and zincoxide (ZnO) are introduced. Optimized devices showed high photoresponse, external quantum efficiency (EQE), and detectivity (D*) values. Under 365 nm 1 mW/cm$^{2}$, the conventional device (ITO/PEDOT:PSS/[(PFE:BNDI) (3:1):8 wt% ZnO]/Al) and the inverted device (ITO/[(PFE:BNDI)(3:1):8 wt% ZnO]/Au) gave photoresponsivities of 515 mA/W and 316 mA/W, D* of 1.12 $\times$ 10$^{14 }$Jones and 0.71 $\times$ 10$^{14 }$Jones, and EQE of 174% and 107%, respectively. Annealing the devices at polymer's glass transition temperature (T$_{g}$ 60 $^{\circ}$ C), enhanced these values to …

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A Switching Inverse Dynamics Controller For Parallel Manipulators Around Drive Singular Configurations, Mustafa Özdemi̇r, Sitki Kemal İder Jan 2016

A Switching Inverse Dynamics Controller For Parallel Manipulators Around Drive Singular Configurations, Mustafa Özdemi̇r, Sitki Kemal İder

Turkish Journal of Electrical Engineering and Computer Sciences

Despite many advantages, parallel manipulators are known to possess drive singularities where the control of one or more degrees of freedom is lost. Around these singular configurations, the required actuator forces grow unbounded. Previous efforts in the literature put forward singularity-consistent trajectory planning and singularity-robust modification of the dynamic equations as a solution to this problem. However, this previous method is applicable only for the open-loop operation of the manipulator, whereas initial configuration errors, external disturbances, and modeling errors should necessarily be taken into account in a closed-loop sense in real-life applications. With this aim, a switching inverse dynamics controller …

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Exploring Feature Sets For Turkish Word Sense Disambiguation, Bahar İlgen, Eşref Adali, Ahmet Cüneyd Tantuğ Jan 2016

Exploring Feature Sets For Turkish Word Sense Disambiguation, Bahar İlgen, Eşref Adali, Ahmet Cüneyd Tantuğ

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents an exploration and evaluation of a diverse set of features that influence word-sense disambiguation (WSD) performance. WSD has the potential to improve many natural language processing (NLP) tasks as being one of the most crucial steps in the area. It is known that exploiting effective features and removing redundant ones help improving the results. There are two groups of feature sets to disambiguate senses and select the most appropriate ones among a set of candidates: collocational and bag-of-words (BoW) features. We introduce the effects of using these two feature sets on the Turkish Lexical Sample Dataset (TLSD), …

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Digital Implementation Of A Constant Frequency Hysteresis Controller For Dual Mode Operation Of An Inverter Acting As A Pv-Grid Interface And Statcom, Lenin Prakash, Arutchelvi Meenakshi Sundaram, Kalyanraj Durairaj Jan 2016

Digital Implementation Of A Constant Frequency Hysteresis Controller For Dual Mode Operation Of An Inverter Acting As A Pv-Grid Interface And Statcom, Lenin Prakash, Arutchelvi Meenakshi Sundaram, Kalyanraj Durairaj

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a new constant frequency hysteresis current controller for the grid interface of a PV-fed three-phase voltage source inverter (VSI) for a dual mode operation, feeding real power during the daytime and reactive power alone during nights, thereby acting as a STATCOM. The constant frequency is inherently achieved by means of digital implementation in a simplified manner without any complex manipulations to choose a variable band width; rather the hysteresis band varies as a natural consequence of selecting appropriate constant sampling frequency. Analytical proof is presented for the switching frequency to remain constant, without compromising on the performance …

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The Simulation Of Sound Signal Masking With Different Chaotic Oscillations And Its Circuit Application, Mehmet Nuri̇ Almali, Zi̇nnur Di̇ki̇ci̇ Jan 2016

The Simulation Of Sound Signal Masking With Different Chaotic Oscillations And Its Circuit Application, Mehmet Nuri̇ Almali, Zi̇nnur Di̇ki̇ci̇

Turkish Journal of Electrical Engineering and Computer Sciences

The chaotic masking process on sound signals using the systems of Lorenz, Rössler, Sprott, Chen, and Arneodo chaotic oscillations are simulated with MATLAB/Simulink. The PID control method providing synchronization in the system is defined and the mean square errors between the times to reach synchronization and the input-output sound signals are compared for the system performance. The Sprott chaotic system is found to be the best synchronized system. Therefore, the application circuits are designed with respect to the Sprott chaotic system and its results are investigated in this study. It is seen that the system marked with the Sprott chaotic …

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Improving Response Time Of Database Systems By Semantification Of Relational Data, Mustafa Yeni̇ad, Yakup Kutlu Jan 2016

Improving Response Time Of Database Systems By Semantification Of Relational Data, Mustafa Yeni̇ad, Yakup Kutlu

Turkish Journal of Electrical Engineering and Computer Sciences

New generation web technologies present the new problem of intelligent representation of data in semantically structured systems. In this study, data hosted in a relational database system were converted to a new generation of web technologies (i.e. Web 3.0) with the semantic mapping method and semantification of the data was accomplished. The success of the transformation procedure was verified by a cross-comparison of the data between the relational database and the semantic data repository. By comparing the response time for performing SQL queries and equivalent SPARQL queries such as select, insert, update, and delete, operations hold in the semantic data …

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A 0.18-$\Mu $M Current-Mode Asynchronous Sigma-Delta Modulator Design, Balkir Kayaalti, Ömer Ceri̇d, Günhan Dündar Jan 2016

A 0.18-$\Mu $M Current-Mode Asynchronous Sigma-Delta Modulator Design, Balkir Kayaalti, Ömer Ceri̇d, Günhan Dündar

Turkish Journal of Electrical Engineering and Computer Sciences

In this study a first-order asynchronous current-mode sigma-delta modulator has been designed and simulated. Asynchronous sigma-delta modulators eliminate the continuous time sigma-delta modulator's problem of signal-to-noise ratio degradation due to clock jitter by avoiding the use of sampling in the modulator loop. Moreover, they provide a higher signal-to-noise ratio even with low-order filters. Thus, considerably low power consumption can be achieved with fewer circuit components. The current mode enables designers to scale the circuits according to different supply voltages and operating currents. In this work, design steps for an asynchronous sigma-delta modulator have been given taking into account its ideal …

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A Comprehensive Control Strategy Of Railway Power Quality Compensator For Ac Traction Power Supply Systems, Hamed Jafari Kaleybar, Siamak Farshad Jan 2016

A Comprehensive Control Strategy Of Railway Power Quality Compensator For Ac Traction Power Supply Systems, Hamed Jafari Kaleybar, Siamak Farshad

Turkish Journal of Electrical Engineering and Computer Sciences

The development of electrical railway systems leads to critical power quality problems in the power grid. This paper discusses a kind of half-bridge-based railway power quality compensator system (HBRPQC) that can compensate negative sequence currents, harmonics, and reactive power simultaneously. In order to keep the HBRPQC performance efficient for the different kinds of transformers used in traction power supply substations, a new multifunctional control strategy that performs better than previous methods is proposed. Due to the fast dynamicity of traction loads, a recessive self-tuning PI controller based on fuzzy logic is adopted in the current control system. The output control …

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Computer-Assisted Cobb Angle Measurement From Posteroanterior Radiographs By A Curve Fitting Method, İbrahi̇m Yildiz Jan 2016

Computer-Assisted Cobb Angle Measurement From Posteroanterior Radiographs By A Curve Fitting Method, İbrahi̇m Yildiz

Turkish Journal of Electrical Engineering and Computer Sciences

Incorrect determination of the top or end vertebrae of a scoliotic curve causes measurement errors when using the Cobb method. Such problems are due to subjectivity. This study was performed to minimize subjectivity by using a curve fitting method. A digitally scanned posteroanterior radiographic image was used for each patient. User-defined midpoints of the curvature, which indicate the midpoints of the vertebrae, were used to fit the polynomial equation. The locations of the top and end vertebrae were calculated using the first derivative of the fitted polynomial equation to obtain the analytical Cobb angle. The interobserver technical error of measurements …

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Certain Investigations On Power Generation Using Repulsive Magnets And New Stepped Dc Coupled Quasi Z-Inverter, Meenakshi Thillainayagam, Suthanthira Vanitha Narayanan, Sujith Kumar Sivaraman Jan 2016

Certain Investigations On Power Generation Using Repulsive Magnets And New Stepped Dc Coupled Quasi Z-Inverter, Meenakshi Thillainayagam, Suthanthira Vanitha Narayanan, Sujith Kumar Sivaraman

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a novel approach for power generation from rotating machines in textile mills using externally coupled repulsive magnets and a new stepped DC coupled Quasi Z-inverter. Power is obtained as a byproduct of the effective harnessing of rotational energy with the use of repulsive magnets. This derived power is stored in a battery arrangement and is retrieved, buck/boosted, and converted to multilevel AC voltage with the new stepped DC coupled quasi Z-inverter. The proposed inverter is powered by isolated voltage sources, uses fewer switches, and produces less distortion in the resulting multilevel voltage compared to its counterpart, and …

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An Interval-Based Contingency Selection Approach Considering Uncertainty, Chao Xu, Wei Gu, Lizi Luo, Jianguo Yao, Shengchun Yang, Ke Wang, Dan Zeng, Miao Fan Jan 2016

An Interval-Based Contingency Selection Approach Considering Uncertainty, Chao Xu, Wei Gu, Lizi Luo, Jianguo Yao, Shengchun Yang, Ke Wang, Dan Zeng, Miao Fan

Turkish Journal of Electrical Engineering and Computer Sciences

Static security assessment is affected by uncertainties of load flow distributions introduced by renewable sources. A fast contingency selection approach based on interval theory is proposed in this paper. Firstly, an interval line active flow calculation algorithm is developed to reduce conservation in application of interval mathematics in line flow calculation. Then a novel interval comparison method based on Bayesian probability theory is applied in interval index comparison to give the relative severity information of contingencies. Finally, an approximately consistent ranking method is utilized in contingency ranking to rank screened contingencies. Numerical studies on several IEEE standard test systems and …

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Validation Of Trnsys Modelling For A Fixed Slope Photovoltaic Panel, Kant Kanyarusoke, Jasson Gryzagoridis, Graeme Oliver Jan 2016

Validation Of Trnsys Modelling For A Fixed Slope Photovoltaic Panel, Kant Kanyarusoke, Jasson Gryzagoridis, Graeme Oliver

Turkish Journal of Electrical Engineering and Computer Sciences

TRNSYS stands for transient system simulation software. This paper describes a procedure that was used to validate a TRNSYS model for estimating electricity yields from a fixed slope photovoltaic (PV) panel. The objective was to find how close to reality predicted energy yield for a specified panel can be, at a location near one of the weather stations listed in the software's database. The software was used to predict daily total incident radiation on a horizontal plane and electrical energy yields from a 90 Wp panel when sloped at 34$^{\circ}$ facing north at a test site in Cape Town, South …

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Integration Of Spectral And Spatial Information Via Local Covariance Matrices For Segmentation And Classification Of Hyperspectral Images, Uğur Ergül, Gökhan Bi̇lgi̇n Jan 2016

Integration Of Spectral And Spatial Information Via Local Covariance Matrices For Segmentation And Classification Of Hyperspectral Images, Uğur Ergül, Gökhan Bi̇lgi̇n

Turkish Journal of Electrical Engineering and Computer Sciences

In this work, a novel approach is presented for the feature extraction step in hyperspectral image processing to form more discriminative features between different pixel regions. The proposed method combines both spatial and spectral information, which is very important for segmentation and classification of hyperspectral images. For comparison, five different feature sets are formed using eigen decomposition of local covariance matrices of subcubes located around a pixel of interest in the scene. Subcubes of neighbor pixels are obtained by a windowed structure to expose pattern similarities. As a novel approach, local covariance matrices are computed in eigenspace and proposed feature …

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Assessment Of Energy Performance Certificate Systems: A Case Study For Residential Buildings In Turkey, Kenan Yi̇ği̇t, Bora Acarkan Jan 2016

Assessment Of Energy Performance Certificate Systems: A Case Study For Residential Buildings In Turkey, Kenan Yi̇ği̇t, Bora Acarkan

Turkish Journal of Electrical Engineering and Computer Sciences

The importance of sustainable development and energy efficiency efforts has increased in the construction sector. Energy-saving efforts for buildings have become more important due to the global energy crisis, and energy rating systems have been developed globally for assessment of energy performance. In this study, international green building certificate and energy performance certificate (EPC) systems are presented. The official EPC system for buildings in Turkey is illustrated with case studies. Energy consumption and greenhouse gas emissions from residential buildings are calculated using the official national software, which is called BEP-TR. The impact of lighting on the total energy performance of …

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Effect Of Transverse Magnetic Field On Low Pressure Argon Discharge, Ehsan Hashemi, Kaveh Niayesh, Hossein Mohseni Jan 2016

Effect Of Transverse Magnetic Field On Low Pressure Argon Discharge, Ehsan Hashemi, Kaveh Niayesh, Hossein Mohseni

Turkish Journal of Electrical Engineering and Computer Sciences

A numerical simulation was performed to investigate the effect of transverse magnetic fields on low pressure argon plasma. Discovering the variations in electric field, electric potential, power consumption in plasma, and dominant physical mechanisms after application of magnetic fields is the main output of this analysis. A simulation was performed using the finite element method. A 2-fluid model equipped with chemical reaction equations in argon plasma, heat transfer equation, and Poisson's equation was used to describe the plasma behavior. Two disk-shaped electrodes separated by 12 mm from each other were considered as a plasma chamber and an external transverse magnetic …

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Minimum Number Of Permanent-Magnet Synchronous Generators For Coordinated Low-Voltage Ride-Through Of Induction Generators In Hybrid Wind Farms, Shenghu Li, Rui An Jan 2016

Minimum Number Of Permanent-Magnet Synchronous Generators For Coordinated Low-Voltage Ride-Through Of Induction Generators In Hybrid Wind Farms, Shenghu Li, Rui An

Turkish Journal of Electrical Engineering and Computer Sciences

Coordinated low-voltage ride-through (LVRT) of induction generators (IGs) utilizing the excessive reactive power of permanent magnet synchronous generators (PMSGs) in hybrid wind farms is attractive due to saving investments on shunt compensators. The existing research is mainly based on dynamic simulations to given scenarios and does not quantify the necessary capacity and number of PMSGs. This paper newly proposes an analytical model to quantify the minimum number of the PMSGs for coordinated LVRT. The critical voltage at the point of common coupling (PCC) leading to slip instability of the IGs is quantified. To avoid instability, necessary var support from the …

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Power Quality Assessment In Different Wind Power Plant Models, Hamid Shariatpanah, Morteza Sabouri Kenari, Roohollah Fadaeinedjad Jan 2016

Power Quality Assessment In Different Wind Power Plant Models, Hamid Shariatpanah, Morteza Sabouri Kenari, Roohollah Fadaeinedjad

Turkish Journal of Electrical Engineering and Computer Sciences

In order to fully study the power quality of a grid-connected wind farm, a suitable model providing accurate output for wind farms is necessary. In this paper, different methods, which have been proposed in previous studies, are investigated with regard to the power quality problem using a squirrel-cage induction generator wind turbine. These models are different in terms of accuracy and simulation time. The question is: which method is more suitable for simulation of a wind farm? To answer this question, a criterion should be introduced to compare different modeling methods. Full turbine representation is introduced as the best criterion …

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Fpga Implementations Of Scale-Invariant Models Of Neural Networks, Zeinulla Zhanabaev, Yeldos Kozhagulov, Dauren Zhexebay Jan 2016

Fpga Implementations Of Scale-Invariant Models Of Neural Networks, Zeinulla Zhanabaev, Yeldos Kozhagulov, Dauren Zhexebay

Turkish Journal of Electrical Engineering and Computer Sciences

Integrated circuit implementations of new models of neural networks with scale-invariant properties are presented. The specifics of such models are necessary in analysis of discrete mappings containing fractional power. We suggest an algorithm for increasing the power of a physical value by using a field-programmable gate array (FPGA). Comparisons between FPGA implementations and numerical results are demonstrated.

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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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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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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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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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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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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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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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An Improved Real-Time Adaptive Kalman Filter With Recursive Noise Covariance Updating Rules, Iyad Hashlamon, Kemaletti̇n Erbatur Jan 2016

An Improved Real-Time Adaptive Kalman Filter With Recursive Noise Covariance Updating Rules, Iyad Hashlamon, Kemaletti̇n Erbatur

Turkish Journal of Electrical Engineering and Computer Sciences

The Kalman filter (KF) is used extensively for state estimation. Among its requirements are the process and observation noise covariances, which are unknown or partially known in real-life applications. Uncertain and biased values of the covariances result in KF performance degradation or divergence. Unlike previous methods, we are using the idea of the recursive estimation of the KF to develop two recursive updating rules for the process and observation covariances, respectively designed based on the covariance matching principles. Each rule has a tuning parameter that enhances its flexibility for noise adaptation. The proposed adaptive Kalman filter (AKF) proves itself to …

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Modified Hexagonal Sierpinski Gasket-Based Antenna Design With Multiband And Miniaturized Characteristics For Uwb Wireless Communication, Ademola Aluwaseun Kaka, Mehmet Toycan Jan 2016

Modified Hexagonal Sierpinski Gasket-Based Antenna Design With Multiband And Miniaturized Characteristics For Uwb Wireless Communication, Ademola Aluwaseun Kaka, Mehmet Toycan

Turkish Journal of Electrical Engineering and Computer Sciences

A modified hexagonal Sierpinski gasket-based fractal antenna is proposed for ultrawide-band (UWB) wireless applications. The designed antenna has miniaturized (36 $\times $ 48 mm$^{2})$ and multiband characteristics. Two design guidelines, the partial ground plane technique and the circular annular ring patch on the substrate, are applied to improve impedance matching and radiation pattern characteristics. According to the simulation results, the proposed modified antenna has a reflection coefficient $S_{11} $ of less than --15 dB, a linear phase of the reflection coefficient, 80{\%} radiation efficiency, 2--4.5 dBi antenna gain, and omnidirectional radiation pattern properties over the full UWB spectrum (3.1--10.6 GHz). …

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Research On Switched Reluctance Machine Drive Topology And Control Strategies For Electric Vehicles, He Cheng, Hao Chen, Lei Ma, Guojun Yu Jan 2016

Research On Switched Reluctance Machine Drive Topology And Control Strategies For Electric Vehicles, He Cheng, Hao Chen, Lei Ma, Guojun Yu

Turkish Journal of Electrical Engineering and Computer Sciences

The electric drive system is one of the key technologies for electric vehicles. First, the energy flow of an electric vehicle is analyzed in the driving, braking, and charging working states. After that, a drive topology that can achieve 3 working states is proposed based on the driving characteristics of a switched reluctance machine. In the driving state, the boost mode of a front-end converter is used to achieve different operating conditions, including low speed with a light load or high speed with a heavy load. In the braking state, the front-end converter is used to implement smooth switching between …

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