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Articles 15541 - 15570 of 25629

Full-Text Articles in Computer Engineering

A New Educational Mobile Devices Platform For Social Inclusion In Tanzania, Fredrick Mtenzi Jan 2016

A New Educational Mobile Devices Platform For Social Inclusion In Tanzania, Fredrick Mtenzi

Articles

Abstract— It is evident that advances in technology has led to improvement in societal wellbeing. In this paper we demonstrate how mobile phones are used in providing reliable and quality education to students in disadvantaged areas of Tanzania. The main contribution is on leveraging on the success that Tanzania has had on using mobile banking to the un-banked population. These lessons are adapted to the education sector, where clever/smart integration of existing disruptive technologies such as mobile phones and social networks are be used to provide access to high quality educational contents. Further, the paper shows how educational content can …

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Modeling Mental Workload Via Rule-Based Expert System: A Comparison With Nasa-Tlx & Workload Profile, Lucas Rizzo, Sarah Jane Delany, Pierpaolo Dondio, Luca Longo Jan 2016

Modeling Mental Workload Via Rule-Based Expert System: A Comparison With Nasa-Tlx & Workload Profile, Lucas Rizzo, Sarah Jane Delany, Pierpaolo Dondio, Luca Longo

Conference papers

In the last few decades several fields have made use of the construct of human mental workload (MWL) for system and task design as well as for assessing human performance. Despite this interest, MWL remains a nebulous concept with multiple definitions and measurement techniques. State-of-the-art models of MWL are usually ad-hoc, considering different pools of pieces of evidence aggregated with different inference strategies. In this paper the aim is to deploy a rule-based expert system as a more structured approach to model and infer MWL. This expert system is built upon a knowledge-base of an expert and transates into computable …

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Kicm: A Knowledge-Intensive Context Model, Fredrick Mtenzi, Denis Lupiana Jan 2016

Kicm: A Knowledge-Intensive Context Model, Fredrick Mtenzi, Denis Lupiana

Conference papers

A context model plays a significant role in developing context-aware architectures and consequently on realizing context-awareness, which is important in today's dynamic computing environments. These architectures monitor and analyse their environments to enable context-aware applications to effortlessly and appropriately respond to users' computing needs. These applications make the use of computing devices intuitive and less intrusive. A context model is an abstract and simplified representation of the real world, where the users and their computing devices interact. It is through a context model that knowledge about the real world can be represented in and reasoned by a context-aware architecture. This …

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

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

Turkish Journal of Electrical Engineering and Computer Sciences

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

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

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

Turkish Journal of Electrical Engineering and Computer Sciences

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

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Heuristic Methods For Postoutage Voltage Magnitude Calculations, Oğuzhan Ceylan, Aydoğan Özdemi̇r, Hasan Dağ Jan 2016

Heuristic Methods For Postoutage Voltage Magnitude Calculations, Oğuzhan Ceylan, Aydoğan Özdemi̇r, Hasan Dağ

Turkish Journal of Electrical Engineering and Computer Sciences

Power systems play a significant role in every aspect of our daily lives. Hence, their continuation without any interruption (or with the least duration of interruption due to faults or scheduled maintenances) is one of the key aims of electrical energy providers. As a result, electrical energy providers need to check in great detail the integrity of their power systems by performing regular contingency studies of the equipment involved. Among others, line and transformer outage simulations constitute an integral part of an electrical management system. Both accuracy and calculation speed depend on the branch outage model and/or the solution algorithms …

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Towards A Semantic-Based Information Extraction System For Matching Résumés To Job Openings, Duygu Çeli̇k Jan 2016

Towards A Semantic-Based Information Extraction System For Matching Résumés To Job Openings, Duygu Çeli̇k

Turkish Journal of Electrical Engineering and Computer Sciences

A curriculum vitae or a résumé, in general, consists of personal details, education, work experience, qualifications, and references. The overall objective of this study was to extract such data as experience, features, and business and education information from résumés stored in human resources repositories. In this article, we propose an ontology-driven information extraction system that is planned to operate on several million free-format textual résumés to convert them to a structured and semantically enriched version for use in semantic data mining of data essential in human resources processes. The architecture and working mechanism of the system, similarity of the concept …

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

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

Turkish Journal of Electrical Engineering and Computer Sciences

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

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

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

Turkish Journal of Electrical Engineering and Computer Sciences

Wavelet packet modulation (WPM) is a potential candidate in wireless communication systems by virtue of its flexibility and modular implementation capability. However, WPM suffers from high peak-to-average power ratio (PAPR), which results in signal distortion when a high-power amplifier is employed at the transmitter. The partial transmit sequence (PTS) is an attractive PAPR reduction method, but its computational complexity is high. In this paper, we propose a PTS based on the genetic algorithm (GA) scheme (GA-PTS) to reduce the computational complexity of the PTS in the lifting-based WPM (LBWPM) systems. Simulation results show that the proposed GA-PTS scheme provides significant …

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

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

Turkish Journal of Electrical Engineering and Computer Sciences

This paper examines the modeling of conducted electromagnetic emissions of integrated circuits. In this study, test circuits were designed and printed circuit boards were prepared to measure the input impedance at the power supply pin of the microcontroller. After S-parameter measurements of the test circuit were performed in a frequency range of 10 MHz to 2 GHz, Z-parameters were obtained via S-parameters. Next, the impedance--frequency curve of the test circuit's power supply pin, which consists of a microcontroller core, printed circuit board, conductive trace, and SMA connector global impedances, was obtained. Therefore, all the traces, printed circuit board, and SMA …

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Modeling Based On 3d Finite Element Analysis And Experimental Study Of A 24-Slot 8-Pole Axial-Flux Permanent-Magnet Synchronous Motor For No Cogging Torque And Sinusoidal Back-Emf, Mehmet Güleç, Ersi̇n Yolaçan, Yücel Demi̇r, Oğuzhan Ocak, Meti̇n Aydin Jan 2016

Modeling Based On 3d Finite Element Analysis And Experimental Study Of A 24-Slot 8-Pole Axial-Flux Permanent-Magnet Synchronous Motor For No Cogging Torque And Sinusoidal Back-Emf, Mehmet Güleç, Ersi̇n Yolaçan, Yücel Demi̇r, Oğuzhan Ocak, Meti̇n Aydin

Turkish Journal of Electrical Engineering and Computer Sciences

This paper discusses cogging torque minimization techniques in surface-mounted, axial-flux, multirotor permanent magnet synchronous disc motors in order to eliminate cogging components and obtain sinusoidal back-EMF for low-speed applications. Cogging torque minimization techniques are examined in detail with a focus on magnet skewing and pole and rotor shifting in order to obtain zero cogging. Some magnet shape and rotor design alternatives with conventional skew planar magnets were investigated based on 3D finite element analysis (FEA). Improvements compared to unskewed reference axial-flux permanent magnet (AFPM) motor design are presented. A prototype AFPM motor was built and tested based on the analyses. …

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Lifetime Maximization Of Wireless Sensor Networks Using Particle Swarm Optimization, Aleem Kabeer Mir, Muhammad Zubair, Ijaz Mansoor Qureshi Jan 2016

Lifetime Maximization Of Wireless Sensor Networks Using Particle Swarm Optimization, Aleem Kabeer Mir, Muhammad Zubair, Ijaz Mansoor Qureshi

Turkish Journal of Electrical Engineering and Computer Sciences

Wireless sensor networks have multiple applications in intelligent environment and structural monitoring. The major challenge in wireless sensor networks is the power constraint. This paper deals with minimizing the energy utilization of wireless sensor nodes and maximizing their overall life span. The objective of our proposed scheme is to find a method for grouping sensors into the maximum number of distinct sensor cover sets to totally monitor the required area. This problem can be solved by using the disjoint cover set problem. Present optimization techniques take much time and deliver unsatisfactory results in large-scale networks. This paper proposes a technique …

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

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

Turkish Journal of Electrical Engineering and Computer Sciences

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

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

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

Turkish Journal of Electrical Engineering and Computer Sciences

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

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

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

Turkish Journal of Electrical Engineering and Computer Sciences

Feedwater control systems are used to maintain the steam generator water level within prescribed narrow limits and to provide constant supply of steam during power demand variations. Current feedwater control systems are often found to be unsatisfactory during startup and low power operations. A robust nonlinear estimator-based optimal algebraic control is developed for feedwater control systems to solve the water level tracking problem during power demand variations. It is shown that the proposed control provides an optimal and robust water level tracking with a single automatic controller over the complete range of power operations in the presence of plant uncertainties …

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

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

Turkish Journal of Electrical Engineering and Computer Sciences

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

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

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

Turkish Journal of Electrical Engineering and Computer Sciences

In this study, a geographic information system (GIS)-based novel fiber network monitoring system has been developed to improve the operation and maintenance of fiber optic networks (FONs). The main aim of the developed system is to provide the required capabilities for both detailed digital modeling and central monitoring of FONs. The system can perform scheduled measurements and dispatch alarms if any fault or degradation is detected in the concerned FON. It also indicates the alarm locations on a map as a considerable contribution to decreasing mean time to repair. The developed monitoring system has more security features than others.

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Linear Model Of A Three-Phase Shunt Active Power Filter With A Hysteresis Controller, Kadi̇r Vardar, Eyup Akpinar Jan 2016

Linear Model Of A Three-Phase Shunt Active Power Filter With A Hysteresis Controller, Kadi̇r Vardar, Eyup Akpinar

Turkish Journal of Electrical Engineering and Computer Sciences

In this work, a linear model of a 3-phase active power filter (APF) is obtained to design a DC link proportional--integral (PI) controller. The system is designed on the basis of a TMS320F2812 digital signal processer (DSP). The PI controller is implemented in the program of the DSP. The hysteresis controller and sampling frequency are also taken into account in the linear model. The effect of hysteresis bandwidth, filter inductance, DC link capacitor, and sampling frequency on the stability are investigated by using the Routh--Hurwitz method. The detailed simulation model in MATLAB and experimental results showed that the linear model …

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A Switchable Approach To Large Object Allocation In Real-Time Java, Veysel Harun Şahi̇n, Ümi̇t Kocabiçak Jan 2016

A Switchable Approach To Large Object Allocation In Real-Time Java, Veysel Harun Şahi̇n, Ümi̇t Kocabiçak

Turkish Journal of Electrical Engineering and Computer Sciences

Over the last 20 years object-oriented programming languages and managed run-times like Java have been very popular because of their software engineering benefits. Despite their popularity in many application areas, they have not been considered suitable for real-time programming. Besides many other factors, one of the barriers that prevent their acceptance in the development of real-time systems is the long pause times that may arise during large object allocation. This paper examines different kinds of solutions that have been developed so far and introduces a switchable approach to large object allocation in real-time Java. A synthetic benchmark application that is …

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

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

Turkish Journal of Electrical Engineering and Computer Sciences

A novel feature extraction called discretization-based entropy is proposed for use in the classification of EEG signals. To this end, EEG signals are decomposed into frequency subbands using the discrete wavelet transform (DWT), the coefficients of these subbands are discretized into the desired number of intervals using the discretization method, the entropy values of the discretized subbands are calculated using the Shannon entropy method, and these are then used as the inputs of the adaptive neuro-fuzzy inference system (ANFIS). The equal width discretization (EWD) and equal frequency discretization (EFD) methods are used for the discretization. In order to evaluate their …

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

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

Turkish Journal of Electrical Engineering and Computer Sciences

Face recognition is an essential issue in modern-day applications since it can be used in many areas for several purposes. Many methods have been proposed for face recognition. It is a difficult task since variations in lighting, instantaneous mimic varieties, posing angles, and scaling differences can drastically change the appearance of the face. To suppress these complications, effective feature extraction and proper alignment of face images gain as much importance as the recognition method choice. In this paper, we provide an extensive comparison of the state-of-the-art face recognition methods with the most well-known techniques used in feature representation. In order …

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

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

Turkish Journal of Electrical Engineering and Computer Sciences

We propose an online palmprint identification and verification algorithm with the use of kernel Fisher discriminant analysis (KFD) on the Gabor wavelet representation of palm images. Desirable palm features are derived by Gabor wavelets on the palm region. The KFD method is then employed to extract higher order relations among the Gabor-palm images for palmprint recognition. As a real-world application, the proposed algorithm was adapted into a novel online palmprint verification system that was employed in a student laboratory for 3 months. The feasibility of the Gabor-based KFD method was successfully tested on our proposed online palmprint system and on …

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Improving The Srf Method To Compensate Low-Order Harmonics Under Nonsinusoidal Network Voltages, Javad Modarresi, Mehdi Fallah, Eskandar Ghokipour, Mohammad Tavakoli Bina Jan 2016

Improving The Srf Method To Compensate Low-Order Harmonics Under Nonsinusoidal Network Voltages, Javad Modarresi, Mehdi Fallah, Eskandar Ghokipour, Mohammad Tavakoli Bina

Turkish Journal of Electrical Engineering and Computer Sciences

Increasing the application of power in electronic devices has increased the harmonics in power systems. Numerous methods like the synchronous reference frame (SRF) and the p-q-based method have been suggested to overcome the effects of these harmonics. The conventional SRF method provides acceptable results in harmonic compensation of high-order harmonics (higher than the fourth order), but the transient response time will be drastically increased in the presence of low-order harmonics due to the existence of a conventional low-pass filter. Furthermore, if the load terminal voltages are distorted, then the conventional SRF method will become unable to implement load current compensation. …

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Relay Coordination Analysis And Protection Solutions For Smart Grid Distribution Systems, Mehmet Tan Turan, Erdi̇n Gökalp Jan 2016

Relay Coordination Analysis And Protection Solutions For Smart Grid Distribution Systems, Mehmet Tan Turan, Erdi̇n Gökalp

Turkish Journal of Electrical Engineering and Computer Sciences

Growing complexity of conventional power grids and their management, increasing power demand and energy quality expectations considering grid reliability, and efficiency and security concerns have triggered the evolution of smart grids. This is an expected result of implementing new technologies in existing grids, including renewable sources such as wind turbines and photovoltaic modules. With implementation of such new elements to the system, the protection concept should be considered by system regulators. In order to analyze protection problems, simulation-based analysis should be carried out before high-cost experimental studies. In this study, a simulation-based evaluation for a smart grid-based distribution system is …

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

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

Turkish Journal of Electrical Engineering and Computer Sciences

A novel chaotic attractor with a fractal wing structure is proposed and analyzed in terms of its basic dynamical properties. The most interesting feature of this system is that it has complex dynamical behavior, especially coexisting attractors for particular ranges of the parameters, including two coexisting periodic or strange attractors that can coexist with a third strange attractor. Amplitude and phase control methods are described since they are convenient for circuit design and chaotic signal applications. An appropriately chosen parameter in a particular quadratic coefficient can realize partial amplitude control. An added linear term can change the symmetry and provide …

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

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

Turkish Journal of Electrical Engineering and Computer Sciences

Due to the ever-increasing demand for more detailed and accurate power system simulations, the dimensions of mathematical models increase. Although the traditional direct linear equation solvers based on LU factorization are robust, they have limited scalability on the parallel platforms. On the other hand, simulations of the power system events need to be performed at a reasonable time to assess the results of the unwanted events and to take the necessary remedial actions. Hence, to obtain faster solutions for more detailed models, parallel platforms should be used. To this end, direct solvers can be replaced by Krylov subspace methods (conjugate …

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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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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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