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2016

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Articles 9331 - 9360 of 9593

Full-Text Articles in Engineering

Hardware Implementation Of A Scale And Rotation Invariant Object Detection Algorithm On Fpga For Real-Time Applications, Murat Peker, Hali̇s Altun, Fuat Karakaya Jan 2016

Hardware Implementation Of A Scale And Rotation Invariant Object Detection Algorithm On Fpga For Real-Time Applications, Murat Peker, Hali̇s Altun, Fuat Karakaya

Turkish Journal of Electrical Engineering and Computer Sciences

A hardware implementation of a computationally light, scale, and rotation invariant method for shape detection on FPGA is devised. The method is based on histogram of oriented gradients (HOG) and average magnitude difference function (AMDF). AMDF is used as a decision module that measures the similarity/dissimilarity between HOG vectors of an image in order to classify the object. In addition, a simulation environment implemented on MATLAB is developed in order to overcome the time-consuming and tedious process of hardware verification on the FPGA platform. The simulation environment provides specific tools to quickly implement the proposed methods. It is shown that …

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Optimal Placing Of Pmus In A Constrained Grid: An Approach, Jyoti Bhonsle, Anjali Junghare Jan 2016

Optimal Placing Of Pmus In A Constrained Grid: An Approach, Jyoti Bhonsle, Anjali Junghare

Turkish Journal of Electrical Engineering and Computer Sciences

Synchronized phasor measurement units (PMUs) are replacing conventional measuring meters in modern power networks. The paradigm of grid monitoring has shifted to a wider area. This offers better monitoring, protection, and control of the overall power grid. This paper presents an approach for optimal placing of PMUs in constrained power grids using the binary integer programming technique. The proposed approach deals with four constraints: 1) observability of network, two cases of fully observable and partially observable networks are investigated; 2) conventional measurements, three cases of zero injection bus and injection measurement, conventional power flow measurement, and both injection and power …

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A New Cmos Logarithmic Current Generator, Munir Al Absi, Karama Al Tamimi Jan 2016

A New Cmos Logarithmic Current Generator, Munir Al Absi, Karama Al Tamimi

Turkish Journal of Electrical Engineering and Computer Sciences

A new CMOS current-mode controllable low-voltage and low-power logarithmic function circuit is proposed. The circuit provides good dynamic range, controllable output, and reasonable accuracy and it is insensitive to temperature variations. The circuit operates with $\pm $0.5 V supply, consumes 0.3 $\mu $W, and has a -3 dB frequency of 2.4 MHz. The functionality of the proposed design is confirmed using Tanner T-spice with 0.35 $\mu $m CMOS process.

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Novel Version Of Bi Input-Extended Kalman Filter For Speed-Sensorless Control Of Induction Motors With Estimations Of Rotor And Stator Resistances, Load Torque, And Inertia, Emrah Zerdali̇, Murat Barut Jan 2016

Novel Version Of Bi Input-Extended Kalman Filter For Speed-Sensorless Control Of Induction Motors With Estimations Of Rotor And Stator Resistances, Load Torque, And Inertia, Emrah Zerdali̇, Murat Barut

Turkish Journal of Electrical Engineering and Computer Sciences

This study aims to develop a novel version of bi input-extended Kalman filter (BI-EKF)-based estimation technique in order to increase the number of state and parameter estimations required for speed-sensorless direct vector control (DVC) systems, which perform velocity and position controls of induction motors (IMs). For this purpose, all states required for the speed-sensorless DVC systems, besides the stator resistance $R_{s} $, the rotor resistance $R_{r}$, the load torque $t_{L}$ including the viscous friction term, and the reciprocal of total inertia $1/j_{T}$, are simultaneously estimated by the novel BI-EKF algorithm using the measured phase currents and voltages. The effectiveness of …

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A Monte Carlo-Based Poisson's Equation Solver Parallelized With Coarray Fortran, Nevsan Şengi̇l, Özgür Tümüklü, Mehmet Cevdet Çelenli̇gi̇l Jan 2016

A Monte Carlo-Based Poisson's Equation Solver Parallelized With Coarray Fortran, Nevsan Şengi̇l, Özgür Tümüklü, Mehmet Cevdet Çelenli̇gi̇l

Turkish Journal of Electrical Engineering and Computer Sciences

Poisson's equation is found in many scientific problems, such as heat transfer and electric field calculations. Although many different techniques are involved in solving Poisson's equation, we focused on the Monte Carlo method (MCM). We preferred the MCM not only because of its simple algorithm but also for its excellent parallel efficiency. Parallelization is one of the most effective techniques for reducing computation time. Among many parallelization paradigms, such as OpenMP (open multiprocessing), MPI (message passing interface), and PGAS (partitioned global address space), we adopted the PGAS-based Coarray Fortran (CAF). In this paper, we demonstrated that parallelization of Poisson's equation …

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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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The Self-Adaptive Alternating Direction Method For The Multiarea Economic Dispatch Problem, Yaming Ren, Shumin Fei, Haikun Wei Jan 2016

The Self-Adaptive Alternating Direction Method For The Multiarea Economic Dispatch Problem, Yaming Ren, Shumin Fei, Haikun Wei

Turkish Journal of Electrical Engineering and Computer Sciences

The alternating direction method has been used widely in the power systems field for solving the multiarea dispatch problem. However, experience with applications has shown that the convergence rate of the alternating direction method depends significantly on the selection of the penalty parameter of the linear consistency constraint. Typically, it is difficult to obtain the optimal penalty parameter in advance. In this paper, for the purpose of solving this problem, we propose centralized and distributed self-adaptive penalty parameter strategies that allow the value of the penalty parameter to increase or decrease based on the information from each iteration. Simulation results …

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A Problem Approximation Surrogate Model (Pasm) For Fitness Approximation In Optimizing The Quantization Table For The Jpeg Baseline Algorithm, Vinoth Kumar Balasubramanian, Karpagam Manavalan Jan 2016

A Problem Approximation Surrogate Model (Pasm) For Fitness Approximation In Optimizing The Quantization Table For The Jpeg Baseline Algorithm, Vinoth Kumar Balasubramanian, Karpagam Manavalan

Turkish Journal of Electrical Engineering and Computer Sciences

The quantization table in the baseline Joint Photographic Experts Group (JPEG) algorithm plays an important role in compression/quality trade-off. Hence the detection of the optimal quantization table is viewed as an optimization problem. The genetic algorithm (GA) is an attractive optimization tool by many researchers for this application due to its ability in dealing with complex problems. In spite of its advantages, the GA requires more computation time to achieve an optimal solution if it has an expensive fitness evaluation. This paper proposes a problem approximation surrogate model (PASM) for fitness approximation to assist the GA in optimizing the quantization …

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Direct Radio Frequency Sampling Methodology For Multiple Signals In An Energy-Sparse Spectrum, Tauqeer Ahmed, Noor Muhammad Khan Jan 2016

Direct Radio Frequency Sampling Methodology For Multiple Signals In An Energy-Sparse Spectrum, Tauqeer Ahmed, Noor Muhammad Khan

Turkish Journal of Electrical Engineering and Computer Sciences

In software defined radio (SDR) systems, it is desirable to down-convert multiple RF signals simultaneously by placing an analogue-to-digital converter (ADC) as near the antenna as possible. Radio frequency (RF) subsampling is one of the established methodologies used by radio receivers to directly down-convert and digitize RF signals. In this paper, we propose a novel direct RF sampling method to find out the minimum sampling frequency for an evenly spaced spectrum comprising multiband RF signals. However, it can also be applied to nonuniformly spaced signals with slight modification. The proposed methodology describes a set of rules to achieve the lowest …

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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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Fpga Implementation Of A Hevc Deblocking Filter For Fast Processing Of Super High Resolution Applications, Awais Khan, Gulistan Raja Jan 2016

Fpga Implementation Of A Hevc Deblocking Filter For Fast Processing Of Super High Resolution Applications, Awais Khan, Gulistan Raja

Turkish Journal of Electrical Engineering and Computer Sciences

This paper proposes the architecture of a deblocking filter (DBF) that removes blocking artifacts in new emerging High Efficiency Video Coding (HEVC). A parallel architecture for both normal and strong filtering modes of HEVC is proposed. Distributed memories and two data paths increase the parallelism and make the architecture more efficient. The proposed architecture is described by Verilog and implemented on FPGA. The architecture can realize real time to compute 4K UHD video at 30 fps by using 46.65 million clocks with total equivalent gate count of 46K. The maximum delay time for output to come after taking input for …

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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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Sinusoidal Current Injection Based On A Line-Commutated Inverter For Single-Phase Grid-Connected Renewable Energy Sources, Murat Ünlü, Sabri̇ Çamur, Ersoy Beşer, Bi̇rol Ari̇foğlu Jan 2016

Sinusoidal Current Injection Based On A Line-Commutated Inverter For Single-Phase Grid-Connected Renewable Energy Sources, Murat Ünlü, Sabri̇ Çamur, Ersoy Beşer, Bi̇rol Ari̇foğlu

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a new power electronic interface based line-commutated inverter (LCI) for dc power injection to the grid. The proposed system involves a simple power electronic converter and controller interface using a single-phase LCI. The controller has been developed that can inject a high quality sinusoidal current to the utility grid from the dc source. By this means, ac side harmonic filters and the harmonic cancellation technique are eliminated. The proposed system facilitates controlling the injected current with a controllable power factor of operation. The complete system has been modeled in MATLAB/Simulink and tested experimentally with the laboratory prototype. …

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Variation Of Photovoltaic System Performance Due To Climatic And Geographical Conditions In Turkey, Betül Bektaş Eki̇ci̇ Jan 2016

Variation Of Photovoltaic System Performance Due To Climatic And Geographical Conditions In Turkey, Betül Bektaş Eki̇ci̇

Turkish Journal of Electrical Engineering and Computer Sciences

This study focuses on the effect of climatic and geographical factors on the performance of photovoltaic systems. For this purpose, 4 different cities (Antalya, İstanbul, Elazığ, and Erzurum) from different climatic zones according to TS 825 Thermal Insulation Requirements in Buildings were selected. The monthly average global and diffuse solar radiation of the cities was calculated numerically with the long-term sunshine duration data (between 1990 and 2012) taken from the Turkish State Meteorological Service. The yearly electric energy generated by the grid-connected photovoltaic systems assumed to be located on the flat roofs of building samples were calculated for each of …

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A Comparative Analysis Of Wind Speed Probability Distributions For Wind Power Assessment Of Four Sites, Vaishali Sohoni, Shivcharan Gupta, Rajeshkumar Nema Jan 2016

A Comparative Analysis Of Wind Speed Probability Distributions For Wind Power Assessment Of Four Sites, Vaishali Sohoni, Shivcharan Gupta, Rajeshkumar Nema

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, five probability distribution functions are employed to fit the wind speed data from four different geographical locations in the world in a preliminary analysis. These wind regimes are selected such that they represent wide ranges of mean wind speeds and present different shapes of wind speed histograms. The wind speed data used for modelling consist of 10-min average SCADA data from three US wind farms and hourly averages recorded at a weather station in Canada. Out of the five, three functions, namely Weibull, Rayleigh, and gamma, which provide a better fit to the data, are selected to …

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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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Modeling, Control, And Power Management For A Grid-Integrated Photo Voltaic, Fuel Cell, And Wind Hybrid System, Ezhilarasan Ganesan, Subhranhsu Sekhar Dash, Chinmaya Samanta Jan 2016

Modeling, Control, And Power Management For A Grid-Integrated Photo Voltaic, Fuel Cell, And Wind Hybrid System, Ezhilarasan Ganesan, Subhranhsu Sekhar Dash, Chinmaya Samanta

Turkish Journal of Electrical Engineering and Computer Sciences

Power management in a grid-integrated power system consisting of distributed renewable energy sources is necessitated by ever-increasing energy consumption, the high cost of production, the limited resource of fossil fuel, and the worsening global environment. Wind and solar power generation are two of the most promising renewable power generation technologies. The growth of wind and photovoltaic (PV) power generation systems has exceeded the most optimistic levels of expectations. Fuel cells (FCs) also have great potential to be green power sources of the future because of the many merits they have, such as high efficiency and zero or low emission of …

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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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A Second-Order Volterra Filter-Based Nonlinear Clipping Detector, Jihwan Park, Joon-Hyuk Chang Jan 2016

A Second-Order Volterra Filter-Based Nonlinear Clipping Detector, Jihwan Park, Joon-Hyuk Chang

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, we propose a novel nonlinear clipping detector based on the second-order Volterra filter for an acoustic echo canceller (AEC). Since the performance of the conventional AEC algorithm drastically deteriorates when nonlinear clipping occurs, the adaptive filter pauses adaptation during the nonlinear clipping periods to avoid unwanted divergence. These nonlinear clipping periods are detected in our method using the magnitude spectrum of the quadratic Volterra filter in lower frequency ranges. Through extensive computer-based simulation results considering an acoustic room environment and various clipping levels, it is found that the proposed approach is effective in detecting the nonlinear clipping …

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Iec 61850-Based Islanding Detection And Load Shedding In Substation Automation Systems, Cagil Ozansoy, Keith Frearson Jan 2016

Iec 61850-Based Islanding Detection And Load Shedding In Substation Automation Systems, Cagil Ozansoy, Keith Frearson

Turkish Journal of Electrical Engineering and Computer Sciences

Distributed generation (DG) systems are common within industrial plants and allow continuity of supply to critical loads. In cases when DG cannot support the entire system load, islanding detection (ID) and load shedding (LS) schemes are required. Such an automation scheme serves to monitor the connection to the grid and generation-load imbalance, and it controls the load shedding process. The design of such schemes has undergone significant revolution from electromechanical relays and PLC systems to the use of communications-enabled intelligent electronic devices. This paper discusses the design of an IEC 61850-based smart ID and LS scheme using a complete system …

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Leveraging Linked Open Data Information Extraction For Data Mining Applications, Rajesh Mahule, Om Prakash Vyas Jan 2016

Leveraging Linked Open Data Information Extraction For Data Mining Applications, Rajesh Mahule, Om Prakash Vyas

Turkish Journal of Electrical Engineering and Computer Sciences

The linked open data cloud, with a huge volume of data from heterogeneous and interlinked datasets, has turned the Web into a large data store. It has attracted the attention of both developers and researchers in the last few years, opening up new dimensions in machine learning and knowledge discovery. Information extraction procedures for these processes use different approaches, e.g., template-based, federated to multiple sources, fixed depth link traversal, etc. They are limited by problems in online access to datasets' SPARQL endpoints, such as servers being down for maintenance, bandwidth narrowing, limited numbers of access points to datasets in particular …

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Applying Metaheuristic Optimization Methods To Design Novel Adaptive Pi-Type Fuzzy Logic Controllers For Load-Frequency Control In A Large-Scale Power Grid, Thimaiphuong Dao, Yaonan Wang, Ngockhoat Nguyen Jan 2016

Applying Metaheuristic Optimization Methods To Design Novel Adaptive Pi-Type Fuzzy Logic Controllers For Load-Frequency Control In A Large-Scale Power Grid, Thimaiphuong Dao, Yaonan Wang, Ngockhoat Nguyen

Turkish Journal of Electrical Engineering and Computer Sciences

Due to the complexity and diversity of large-scale power systems in practice, designing load-frequency control (LFC) strategies against load variations faces big challenges to ensure the stability and economy of the network. The focus of this paper is to design a novel adaptive PI-type fuzzy logic (FL)-based LFC architecture for solving the LFC problem in such an interconnected electric power grid. Applying 2 biologically inspired optimization methods, namely particle swarm optimization method and a genetic algorithm, the membership functions and rule base of a basic PI-type FL model were parameterized and optimized simultaneously and successfully. An online self-tuning method was …

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Multilayer Authorization Model And Analysis Of Authorization Methods, Alper Uğur, İbrahi̇m Soğukpinar Jan 2016

Multilayer Authorization Model And Analysis Of Authorization Methods, Alper Uğur, İbrahi̇m Soğukpinar

Turkish Journal of Electrical Engineering and Computer Sciences

There are various methods proposed in the literature to provide authorization control in workflows and information systems. Authorization implementations have deficiencies based on procedural scope. Basic login mechanisms grant system-wide access; the provided margins are broad. Access control lists provide limited definition on access restrictions; the authorization is bounded by these definitions. Role based authorizations do not cover regulations in institutions where the regulations describe specific operations and their operational procedures in institutional workflows. The proposed multilayer authorization model depicts the attributes of authorization mechanisms and analyzes the methods according to their authorization capabilities and contributions to the reliability of …

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Balancing Exploration And Exploitation By Using Sequential Execution Cooperation Between Artificial Bee Colony And Migrating Birds Optimization Algorithms, Hasan Makas, Nejat Yumuşak Jan 2016

Balancing Exploration And Exploitation By Using Sequential Execution Cooperation Between Artificial Bee Colony And Migrating Birds Optimization Algorithms, Hasan Makas, Nejat Yumuşak

Turkish Journal of Electrical Engineering and Computer Sciences

The artificial bee colony (ABC) algorithm is a metaheuristic search method inspired by bees' foraging behaviour. With its global search ability in scout bee phase, it can easily escape from local optimum traps in the problem space. Therefore, it is good at exploration. The migrating birds optimization (MBO) algorithm is another recent metaheuristic search method. It simulates birds' V flight formation, which minimizes energy consumption during flight. The MBO algorithm achieves a good convergence to the global optimum by using its own unique benefit mechanism. That is, it has a good exploitation capability. This paper aimed to combine the good …

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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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