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Articles 136381 - 136410 of 304257

Full-Text Articles in Physical Sciences and Mathematics

Fast And De-Noise Support Vector Machine Training Method Based On Fuzzy Clustering Method For Large Real World Datasets, Omid Naghash Almasi, Modjtaba Rouhani Jan 2016

Fast And De-Noise Support Vector Machine Training Method Based On Fuzzy Clustering Method For Large Real World Datasets, Omid Naghash Almasi, Modjtaba Rouhani

Turkish Journal of Electrical Engineering and Computer Sciences

Classifying large and real-world datasets is a challenging problem in machine learning algorithms. Among the machine learning methods, the support vector machine (SVM) is a well-known approach with high generalization ability. Unfortunately, while the number of training data increases and the data contain noise, the performance of SVM significantly decreases. In this paper, a fast and de-noise two-stage method for training SVMs to deal with large, real-world datasets is proposed. In the first stage, data that contain noises or are suspected to be noisy are identified and eliminated from the genuine training dataset. The process of elimination and identification is …

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Analysis Of Active Power Control Algorithms Of Variable Speed Wind Generators For Power System Frequency Stabilization, Jakub Osmic, Mirza Kusljugic, Elvisa Becirovic, Daniel Toal Jan 2016

Analysis Of Active Power Control Algorithms Of Variable Speed Wind Generators For Power System Frequency Stabilization, Jakub Osmic, Mirza Kusljugic, Elvisa Becirovic, Daniel Toal

Turkish Journal of Electrical Engineering and Computer Sciences

A modified control algorithm of a variable speed wind generator (VSWG) for supporting power system frequency stabilization is presented in this paper. A comparison of the performance of this algorithm with active power control algorithms of VSWGs for supporting power system frequency stabilization, as published in the scientific literature, is also presented. A systematic method of analysis of the modified control algorithm is described in detail. It has been shown that by using the modified control algorithm, the VSWG ''truly'' emulates the inertial response of a conventional steam-generating unit with synchronous generators during the initial/inertial phase of primary frequency control, …

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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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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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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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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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Small Signal Analysis For Dc Bus Voltage Disturbance Resistance Of Voltage Source Converter, Yingjie Wang, Xiaojie Wu, Ping Lu, Yonglei Zhang Jan 2016

Small Signal Analysis For Dc Bus Voltage Disturbance Resistance Of Voltage Source Converter, Yingjie Wang, Xiaojie Wu, Ping Lu, Yonglei Zhang

Turkish Journal of Electrical Engineering and Computer Sciences

The DC bus voltage of the voltage source converter (VSC) is prone to large fluctuation and even to losing its stability for the large mutation of grid voltage or DC-link loads. First the characteristics of two-step transmission to power in the VSC are analyzed, proving that it is inevitable for DC bus voltage fluctuation to occur when grid voltage or DC-link loads mutate. A new two-step feedforward control strategy is then put forward for curbing the fluctuation, which overcomes the shortcoming by which the traditional feedforward control strategy is affected for the performance of current control. The small signal models …

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Behavior-Based Detection Of Application Layer Distributed Denial Of Service Attacks During Flash Events, Renukadevi Saravanan, Saraswathi Shanmuganathan, Yogesh Palanichamy Jan 2016

Behavior-Based Detection Of Application Layer Distributed Denial Of Service Attacks During Flash Events, Renukadevi Saravanan, Saraswathi Shanmuganathan, Yogesh Palanichamy

Turkish Journal of Electrical Engineering and Computer Sciences

Distributed denial of service (DDoS) attacks are ever threatening to the developers and users of the Internet. DDoS attacks targeted at the application layer are especially difficult to be detected since they mimic the legitimate users' requests. The situation becomes more serious when they occur during flash events. A more sophisticated algorithm is required to detect such attacks during a flash crowd. A few existing works make use of flow similarity for differentiating flash crowds and DDoS, but flow characteristics alone cannot be used for effective detection. In this paper, we propose a novel mechanism for discriminating DDoS and flash …

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Feature Selection For Movie Recommendation, Zehra Çataltepe, Mahi̇ye Uluyağmur, Esengül Tayfur Jan 2016

Feature Selection For Movie Recommendation, Zehra Çataltepe, Mahi̇ye Uluyağmur, Esengül Tayfur

Turkish Journal of Electrical Engineering and Computer Sciences

TV users have an abundance of different movies they could choose from, and with the quantity and quality of data available both on user behavior and content, better recommenders are possible. In this paper, we evaluate and combine different content-based and collaborative recommendation methods for a Turkish movie recommendation system. Our recommendation methods can make use of user behavior, different types of content features, and other users' behavior to predict movie ratings. We gather different types of data on movies, such as the description, actors, directors, year, and genre. We use natural language processing methods to convert the Turkish movie …

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Design And Implementation Of A Man-Overboard Emergency Discovery System Based On Wireless Sensor Networks, Abdullah Sevi̇n, Cüneyt Bayilmiş, İsmai̇l Ertürk, Hüseyi̇n Eki̇z, Ahmet Karaca Jan 2016

Design And Implementation Of A Man-Overboard Emergency Discovery System Based On Wireless Sensor Networks, Abdullah Sevi̇n, Cüneyt Bayilmiş, İsmai̇l Ertürk, Hüseyi̇n Eki̇z, Ahmet Karaca

Turkish Journal of Electrical Engineering and Computer Sciences

Recently, wireless sensor networks (WSNs) have been widely employed in many different fields such as military, surveillance, health, agricultural, automation, and environmental monitoring. This paper presents a designed and implemented WSN-based man-overboard emergency discovery system, abbreviated as W-MEDS, that discovers the location of a person in emergency circumstances and runs an alarm system on a ship. The developed W-MEDS carries out a fast man-overboard (MOB) discovery and initiates the vital rescue procedure. It mainly consists of a WSN and a control and discovery system. When a MOB accident occurs, this situation is easily detected through the WSN nodes capable of …

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Economic Assessment Of A Hybrid Turboexpander-Fuel Cell Gas Energy Extraction Plant, Ahmad Darabi, Ahmad Shariati, Reza Ghanaee, Ali Soleimani Jan 2016

Economic Assessment Of A Hybrid Turboexpander-Fuel Cell Gas Energy Extraction Plant, Ahmad Darabi, Ahmad Shariati, Reza Ghanaee, Ali Soleimani

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, a hybrid turboexpander-fuel cell (TE-FC) is investigated for extraction of electrical energy from high pressure gas in which the fuel cells are used for preheating the gas. Combination of expanders and fuel cells will reduce the fuel consumption and greenhouse gas emission. This study reveals that there are some circumstances in which the use of fuel cells in conjunction with a turboexpander is not recommended from an economic point of view. This paper seeks the region in which utilization of fuel cells along with a turboexpander presents maximum economic profit. Using the strategy provided in this paper …

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A Mapreduce-Based Distributed Svm Algorithm For Binary Classification, Ferhat Özgür Çatak, Mehmet Erdal Balaban Jan 2016

A Mapreduce-Based Distributed Svm Algorithm For Binary Classification, Ferhat Özgür Çatak, Mehmet Erdal Balaban

Turkish Journal of Electrical Engineering and Computer Sciences

Although the support vector machine (SVM) algorithm has a high generalization property for classifying unseen examples after the training phase~and a small loss value, the algorithm is not suitable for real-life classification and regression problems. SVMs cannot solve hundreds of thousands of examples in a training dataset. In previous studies on distributed machine-learning algorithms, the SVM was trained in a costly and preconfigured computer environment. In this research, we present a MapReduce-based distributed parallel SVM training algorithm for binary classification problems. This work shows how to distribute optimization problems over cloud computing systems with the MapReduce technique. In the second …

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Quantitative Information Extraction From Gas Sensor Data Using Principal Component Regression, Ahmet Özmen, Beki̇r Mumyakmaz, Mehmet Ali̇ Ebeoğlu, Ci̇hat Taşaltin, İlke Gürol, Zafer Zi̇ya Öztürk, Deni̇z Dural Jan 2016

Quantitative Information Extraction From Gas Sensor Data Using Principal Component Regression, Ahmet Özmen, Beki̇r Mumyakmaz, Mehmet Ali̇ Ebeoğlu, Ci̇hat Taşaltin, İlke Gürol, Zafer Zi̇ya Öztürk, Deni̇z Dural

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a novel use of the principal component analysis (PCA) and regression methods for quantitative feature extraction from gas sensor data. In this approach, PCA plots are interpreted by observing the locations of samples in the principal component domain. A trainable data processing system that also produces numerical output is designed to validate the method. The main advantages of this system are: 1) retrainability: once it is trained, it can be used for any gas set; 2) flexibility: adaptation to different targets does not require hardware modifications (if a sufficient number and variety of sensors are installed in …

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A Generalized Design Method For Multifunction Converters Used In A Photovoltaic System, Trung Nhan Nguyen, An Luo Jan 2016

A Generalized Design Method For Multifunction Converters Used In A Photovoltaic System, Trung Nhan Nguyen, An Luo

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, a general design method for multifunction converters using photovoltaic systems is proposed. With the proposed converter, the photovoltaic generator can provide flexibility, accuracy, and fast responses in both harmonic suppression and power injection modes in all cases of the grid-connected load. The controller for the proposed converter is designed based on the Lyapunov technique, along with the generalized algorithm for determining the global optimal values of the stability bounds. Therefore, the proposed converter can perform accurately and efficiently in the case of fixed system parameters as well as in the case of varying system parameters. Simulations and …

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Performance Analysis Of Biogeography-Based Optimization For Automatic Voltage Regulator System, Uğur Güvenç, Ali̇ Hakan Işik, Tuncay Yi̇ği̇t, İbrahi̇m Akkaya Jan 2016

Performance Analysis Of Biogeography-Based Optimization For Automatic Voltage Regulator System, Uğur Güvenç, Ali̇ Hakan Işik, Tuncay Yi̇ği̇t, İbrahi̇m Akkaya

Turkish Journal of Electrical Engineering and Computer Sciences

A self-tuning method to determine the appropriate parameters of a proportional-integral-derivative controller for an automatic voltage regulator (AVR) system using a biogeography-based optimization (BBO) algorithm is proposed in this study. The BBO algorithm was developed based on the theory of biogeography, which describes migration and its results. We propose that the BBO algorithm has a high-quality solution and stable convergence characteristics, and thus it improves the transient response of the controlled system. The performance of the BBO algorithm depends on the transient response, root locus, and Bode analysis. Robustness analysis is done in the AVR system, which is tuned by …

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Site-Specific Design Optimization Of Horizontal-Axis Wind Turbine Systems Using Pso Algorithm, Ulaş Emi̇noğlu Jan 2016

Site-Specific Design Optimization Of Horizontal-Axis Wind Turbine Systems Using Pso Algorithm, Ulaş Emi̇noğlu

Turkish Journal of Electrical Engineering and Computer Sciences

Due to the complexity of wind turbine systems (WTSs) containing multiple components, design parameters of a WTS must match each other in order to produce electrical energy at a lower cost and a higher efficiency. In this study, a framework for site-specific design optimization of a horizontal-axis WTS is proposed. It is based on cost reduction and the objective function is the produced energy cost. The cost of energy model proposed by the National Renewable Energy Laboratory is utilized. In order to compute turbine output power that results in annual energy production, a new approach is proposed to model the …

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An Advanced Optimization Technique For Considering Reliability Issues And Unit Commitment Problems Simultaneously, Ahmad Heidari, Mohammad Reza Alizadeh Pahlavani, Hamid Dehghani Jan 2016

An Advanced Optimization Technique For Considering Reliability Issues And Unit Commitment Problems Simultaneously, Ahmad Heidari, Mohammad Reza Alizadeh Pahlavani, Hamid Dehghani

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents an advanced optimization technique to solve unit commitment problems and reliability issues simultaneously for thermal generating units. To solve unit commitment, generalized Benders decomposition along with a genetic algorithm are proposed to include minimum up/down time constraints, and for reliability issues consideration, a fuzzy stochastic-based technique is presented. To implement the problem into an optimization program, MATLAB software and CPLEX and KNITRO solvers are applied. To verify the proposed technique and algorithm, two case studies, the IEEE 14- and 118-bus systems, are implemented for optimal generation scheduling and reliability issues. Finally, a comparison with other solution techniques …

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An Unsupervised Heterogeneous Log-Based Framework For Anomaly Detection, Asif Iqbal Hajamydeen, Nur Izura Udzir, Ramlan Mahmod, Abdul Azim Abdul Ghani Jan 2016

An Unsupervised Heterogeneous Log-Based Framework For Anomaly Detection, Asif Iqbal Hajamydeen, Nur Izura Udzir, Ramlan Mahmod, Abdul Azim Abdul Ghani

Turkish Journal of Electrical Engineering and Computer Sciences

Log analysis is a method to identify intrusions at the host or network level by scrutinizing the log events recorded by the operating systems, applications, and devices. Most work contemplates a single type of log for analysis, leading to an unclear picture of the situation and difficulty in deciding the existence of an intrusion. Moreover, most existing detection methods are knowledge-dependent, i.e. using either the characteristics of an anomaly or the baseline of normal traffic behavior, which limits the detection process to only anomalies based on the acquired knowledge. To discover a wide range of anomalies by scrutinizing various logs, …

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Grid-Connected Induction Generator Interturn Fault Analysis Using A Pca-Ann-Based Algorithm, Haydar Bayar, Ümi̇t Kemaletti̇n Terzi̇ Jan 2016

Grid-Connected Induction Generator Interturn Fault Analysis Using A Pca-Ann-Based Algorithm, Haydar Bayar, Ümi̇t Kemaletti̇n Terzi̇

Turkish Journal of Electrical Engineering and Computer Sciences

It is difficult for short circuits among the internal windings of one phase in electrical machines to be determined in a reliable and speedy manner. The failure currents that occur, especially in short circuits with a few windings, are at such low levels that they cannot be determined by relay systems. This results in growing faults and damage. In this study, we designed a model that can define winding failures successfully at very small levels by using the PCA and ANN algorithms. We tested the real-time faults and measured the system performance with the installed test rig. The developed protection …

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Source Detection And Propagation Of Equal Frequency Voltage Flicker In Nonradial Power System, Abdolmajid Dejamkhooy, Ali Dastfan, Alireza Ahmadyfard Jan 2016

Source Detection And Propagation Of Equal Frequency Voltage Flicker In Nonradial Power System, Abdolmajid Dejamkhooy, Ali Dastfan, Alireza Ahmadyfard

Turkish Journal of Electrical Engineering and Computer Sciences

Nowadays electric power quality problems such as flicker (voltage fluctuation) are major concerns of electric companies and industrial consumers. Identification of flicker sources is an important stage in the flicker reduction process. Flicker source can be modeled as a nonlinear load whose admittance is intermittent and time-variant. In the steady state, fluctuation of voltage amplitude is a function of the impedance of flicker sources. In this paper, after calculating the gradient of voltage amplitudes and constructing a Jacobian matrix, criteria for flicker source detection are proposed. Therefore, by measuring voltage and current of each load in the power system, the …

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The Process Of Creeping Discharge-Caused Damage On Oil/Pressboard Insulation, Ruijin Liao, Ende Hu, Lijun Yang, Lian Duan Jan 2016

The Process Of Creeping Discharge-Caused Damage On Oil/Pressboard Insulation, Ruijin Liao, Ende Hu, Lijun Yang, Lian Duan

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents experimental research on creeping discharge by using cylinder-plate electrode configurations under AC voltages. The process of creeping discharge-caused damage on the oil/pressboard insulation was studied. First, the electric field distribution was achieved by Multiphysics software simulation. Afterwards, the phenomena that occurred in the entire damage process, such as ``white smoke'', ``white mark'', and ``black mark'', were recorded and analyzed. Furthermore, the micromorphology of the oil-impregnated pressboard was observed via scanning electron microscope (SEM). Finally, the inner mechanism of the damage to the oil/pressboard insulation was explored according to the phenomena and the SEM morphologies. Results showed that …

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A New Single Stage Single Phase Power Factor Corrected And Isolated Ac-Dc Converter Based On Resonance And Soft Switching, Haci Bodur, Erdem Akboy, İsmai̇l Aksoy Jan 2016

A New Single Stage Single Phase Power Factor Corrected And Isolated Ac-Dc Converter Based On Resonance And Soft Switching, Haci Bodur, Erdem Akboy, İsmai̇l Aksoy

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, a new single stage single phase power factor corrected and isolated AC-DC converter based on resonance and soft switching (SS) is presented. In fact, a new concept for power factor corrected converter is proposed in this study. This converter provides power factor correction (PFC) by using a switch and a fully resonant circuit. It also provides regulated and isolated output voltage with direct power transfer by using a second switch and forward and flyback topologies based on resonance. Both switches in the converter are controlled with the same closed loop and the time multiplexing, and are switched …

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Comparative Study Of Drive Systems Using Vector-Controlled Pmsm Fed By A Matrix Converter And A Conventional Frequency Converter, Pawel Szczesniak, Konrad Urbanski, Zbigniew Fedyczak, Krzysztof Zawirski Jan 2016

Comparative Study Of Drive Systems Using Vector-Controlled Pmsm Fed By A Matrix Converter And A Conventional Frequency Converter, Pawel Szczesniak, Konrad Urbanski, Zbigniew Fedyczak, Krzysztof Zawirski

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a comparative study of a drive system with a permanent magnet synchronous motor fed by a matrix converter and a voltage source inverter with diode rectifier stage. A rotor-oriented vector control is implemented in the drive control. Space vector modulation techniques are used for both converters in the output current modulation process. Initial simulation test results and comparison are presented. The advantages of both solutions are indicated. Special attention is given to the drive control in the low speed range. The main aim of this article is to present drive systems with a matrix converter as an …

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Online Monitoring And Accident Diagnosis Aid System For The Nur Nuclear Research Reactor, Amina Nasrine Allalou, Mohamed Tadjine, Mohamed Seghir Boucherit Jan 2016

Online Monitoring And Accident Diagnosis Aid System For The Nur Nuclear Research Reactor, Amina Nasrine Allalou, Mohamed Tadjine, Mohamed Seghir Boucherit

Turkish Journal of Electrical Engineering and Computer Sciences

This paper deals with the design of a computerized monitoring and diagnosis aid system (CMDAS) for the Nur Nuclear Research Reactor based on real-time plant-specific safety parameters. The CMDAS carries out early detection and identification of accidents that might affect this reactor using supervised neural networks. The graphical programming language LabVIEW is used for creating a human--operator interface, networking, embedding the diagnosis procedure, and handling and storing the data. The methodology presented in this paper can be adapted for any nuclear research reactor.

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Multiple Perspectives On The Hardware Implementations Of Biological Neuron Models And Programmable Design Aspects, Ni̇met Korkmaz, İsmai̇l Öztürk, Recai̇ Kiliç Jan 2016

Multiple Perspectives On The Hardware Implementations Of Biological Neuron Models And Programmable Design Aspects, Ni̇met Korkmaz, İsmai̇l Öztürk, Recai̇ Kiliç

Turkish Journal of Electrical Engineering and Computer Sciences

A few individual design examples of programmable device-based biological neuron model implementations are available in the literature, but there is no comprehensive study that examines analog and digital programmable design examples of frequently studied biological neuron model implementations. The aim of this paper is to present a comparative study about programmable and reconfigurable implementations of the FitzHugh--Nagumo, Izhikevich, and Hindmarsh--Rose neuron models. Since field programmable analog array (FPAA) and field programmable gate array (FPGA) devices offer several advantages such as flexible design possibilities, reduction of the complexity of design, real-time modification, and software control for programmable and reconfigurable implementations of …

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Scale Invariant And Fixed-Length Feature Extraction By Integrating Discrete Cosine Transform And Autoregressive Signal Modeling For Palmprint Identification, Burhan Ergen Jan 2016

Scale Invariant And Fixed-Length Feature Extraction By Integrating Discrete Cosine Transform And Autoregressive Signal Modeling For Palmprint Identification, Burhan Ergen

Turkish Journal of Electrical Engineering and Computer Sciences

Recently, the need for automatic identification has caused researchers to focus on biometric identification methods. Palmprint-based biometric identification has several advantages such as user friendliness, low-cost capturing devices, and robustness. In this paper, a method that integrates the discrete cosine transform (DCT) and an autoregressive (AR) signal modeling is proposed for biometric identification. The method provides scale invariance and produces a fixed-length feature vector. In particular, the Burg algorithm is used for the determination of the AR parameters used as a feature vector. Experimental results demonstrate that a small number of the AR parameters that are modeling the DCT coefficients …

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Improved Direct Power Control For 3-Level Ac/Dc Converter Under Unbalanced And/Or Distorted Voltage Source Conditions, Imad Merzouk, Mohamed Lokmane Bendaas Jan 2016

Improved Direct Power Control For 3-Level Ac/Dc Converter Under Unbalanced And/Or Distorted Voltage Source Conditions, Imad Merzouk, Mohamed Lokmane Bendaas

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, an improved direct power control with space vector modulation for a 3-phase 3-level neutral point clamped converter supplied by unbalanced and/or distorted grid voltage is proposed. The main objective of the control scheme is to obtain balanced and sinusoidal input current with unity power factor under nonideal voltage supply. To achieve the control objectives, compensated active and reactive powers are calculated and added to the referencing one. A theoretical analysis of active and reactive power under a nonideal source is clearly demonstrated. In order to calculate the compensated powers, the extraction of positive, negative, and harmonic sequences …

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

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

Turkish Journal of Electrical Engineering and Computer Sciences

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

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

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

Turkish Journal of Electrical Engineering and Computer Sciences

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

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Audience Segmentation For Campaign Design: Addressing Climate Change In Singapore, Benjamin H. Detenber, Sonny Rosenthal, Youqing Liao, Shirley S. Ho Jan 2016

Audience Segmentation For Campaign Design: Addressing Climate Change In Singapore, Benjamin H. Detenber, Sonny Rosenthal, Youqing Liao, Shirley S. Ho

Research Collection College of Integrative Studies

A nationally representative telephone survey (n = 1,006) was conducted to understand how different groups of Singaporeans regard the issue of climate change and their inclination toward action in dealing with it. We measured attitudes, knowledge, and perceptions of the problem of climate change and the role of various stakeholders in addressing it. The data were subjected to a latent class analysis to produce three distinctive segments of the population: the concerned, the disengaged, and the passive. These segments stand in contrast to those discovered in the United States, Australia, Germany, and India and suggest different strategies for public engagement …

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