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2017

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Articles 11941 - 11970 of 12521

Full-Text Articles in Physical Sciences and Mathematics

An Inductorless Wideband Lna With A New Noise Canceling Technique, Pouria Pazhouhesh Moghadam, Adib Abrishamifar Jan 2017

An Inductorless Wideband Lna With A New Noise Canceling Technique, Pouria Pazhouhesh Moghadam, Adib Abrishamifar

Turkish Journal of Electrical Engineering and Computer Sciences

An inductorless wideband low-noise amplifier (LNA) employing a new noise canceling technique for multistandard applications is presented. The main amplifier has a cascode common gate structure, which provides good input impedance matching and isolation. The proposed noise canceling technique not only improves the noise figure and power gain but also embeds a g$_{m}$-boosting technique in itself, which reduces the power consumption of the main amplifier. Using current-steering and current-reuse techniques in the noise canceling branch makes the design realizable and low power. The proposed LNA is simulated and optimized in 0.13 $\mu $m CMOS technology. The LNA achieves a noise …

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Advanced Probabilistic Power Flow Methodology For Power Systems With Renewable Resources, Dinh Duong Le, Nhi Thi Ai Nguyen, Van Duong Ngo, Alberto Berizzi Jan 2017

Advanced Probabilistic Power Flow Methodology For Power Systems With Renewable Resources, Dinh Duong Le, Nhi Thi Ai Nguyen, Van Duong Ngo, Alberto Berizzi

Turkish Journal of Electrical Engineering and Computer Sciences

Renewable~resources have added additional uncertainty to power grids. Deterministic power flow does not provide sufficient information for power system calculation and analysis, since all sources of uncertainty are not taken into account. To handle uncertainties PPF has been introduced and used as an efficient tool. In this paper, we present a cumulant-based PPF approach that can account for various sources of uncertainty in power systems with renewable resources such as wind and photovoltaic energy. We also propose the use of a new methodology to estimate probability distribution for wind power output based on measured data. The proposed approach is carried …

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Traffic Density Estimation Via Kde And Nonlinear Ls, Mi̇kai̇l Erdem, Mehmet Kemal Özdemi̇r Jan 2017

Traffic Density Estimation Via Kde And Nonlinear Ls, Mi̇kai̇l Erdem, Mehmet Kemal Özdemi̇r

Turkish Journal of Electrical Engineering and Computer Sciences

With increasing population, the determination of traffic density becomes critical in managing urban city roads for safer driving and low carbon emissions. In this study, kernel density estimation is utilized in order to estimate traffic density more accurately when the speeds of vehicles are available for a given region. For the proposed approach, as a first step, the probability density function of the speed data is modeled by kernel density estimation. Then the speed centers from the density function are modeled as clusters. The cumulative distribution function of the speed data is then determined by Kolmogorov--Smirnov test, whose complexity is …

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A Comparison Of Feature Extraction Techniques For Malware Analysis, Mohammad Imran, Muhammad Tanvir Afzal, Muhammad Abdul Qadir Jan 2017

A Comparison Of Feature Extraction Techniques For Malware Analysis, Mohammad Imran, Muhammad Tanvir Afzal, Muhammad Abdul Qadir

Turkish Journal of Electrical Engineering and Computer Sciences

The manifold growth of malware in recent years has resulted in extensive research being conducted in the domain of malware analysis and detection, and theories from a wide variety of scientific knowledge domains have been applied to solve this problem. The algorithms from the machine learning paradigm have been particularly explored, and many feature extraction methods have been proposed in the literature for representing malware as feature vectors to be used in machine learning algorithms. In this paper we present a comparison of several feature extraction techniques by first applying them on system call logs of real malware, and then …

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Maximum Size Of The Pareto Cost Sets For Multi-Constrained Optimal Routing, Derya Yiltaş Kaplan Jan 2017

Maximum Size Of The Pareto Cost Sets For Multi-Constrained Optimal Routing, Derya Yiltaş Kaplan

Turkish Journal of Electrical Engineering and Computer Sciences

Routing under multiple independent constrains in point-to-point networks has been studied for over 10 years. Its NP-hardness keeps pushing researchers to study approximate algorithms and heuristics, and many results have been published in these years. To the best of our knowledge, the nature of its average case has been explored only for the self-adaptive multiple constraints routing algorithm (SAMCRA), which is an algorithm about multiple constraints routing. In this paper, we simplify SAMCRA into a format that is convenient for our average case analysis. This variant algorithm gives optimal solutions also for very large dimensional networks such as with more …

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Assessing The Importance Of Features For Detection Of Hard Exudates In Retinal Images, Kemal Akyol, Baha Şen, Şafak Bayir, Hasan Basri̇ Çakmak Jan 2017

Assessing The Importance Of Features For Detection Of Hard Exudates In Retinal Images, Kemal Akyol, Baha Şen, Şafak Bayir, Hasan Basri̇ Çakmak

Turkish Journal of Electrical Engineering and Computer Sciences

Diabetes disrupts the operation of the eye and leads to vision loss, affecting particularly the nerve layer and capillary vessels in this layer by changes in the blood vessels of the retina.~Suddenly loss and blurred vision problems occur in the image, depending on the phase of the disease, called diabetic retinopathy. Hard exudates are one of the primary signs of diabetic retinopathy. Automatic recognition of hard exudates in retinal images can contribute to detection of the disease. We present an automatic screening system for the detection of hard exudates. This system consists of two main steps. Firstly, the features were …

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A Clustering Approach Using A Combination Of Gravitational Search Algorithm And K-Harmonic Means And Its Application In Text Document Clustering, Mina Mirhosseini Jan 2017

A Clustering Approach Using A Combination Of Gravitational Search Algorithm And K-Harmonic Means And Its Application In Text Document Clustering, Mina Mirhosseini

Turkish Journal of Electrical Engineering and Computer Sciences

Data clustering is one of the most popular techniques of information management, which is used in many applications of science and engineering such as machine learning, pattern reorganization, image processing, data mining, and web mining. Different algorithms have been suggested by researchers, where the evolutionary algorithms are the best in data clustering and especially in big datasets. It is illustrated that GSA-KM, which is a combination of the gravitational search algorithm (GSA) and K-means (KM), is superior over some other comparative evolutionary methods. One of the drawbacks of this approach is dependency on the initial seeds. In this paper, a …

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A Compact Wideband Printed Antenna For Free-Space Radiometricdetection Of Partial Discharge, Yong Zhang, Pavlos Lazaridis, Raed Abd-Alhameed, Ian Glover Jan 2017

A Compact Wideband Printed Antenna For Free-Space Radiometricdetection Of Partial Discharge, Yong Zhang, Pavlos Lazaridis, Raed Abd-Alhameed, Ian Glover

Turkish Journal of Electrical Engineering and Computer Sciences

A microstrip line-fed wideband printed antenna is presented for radio detection of partial discharge (PD). The novel simple structure antenna has compact size of 24 $\times $ 20 $\times $ 0.16 cm$^{3}$ (0.28$\lambda_{s} \times $ 0.23 $\lambda_{s} \times $ 0.002 $\lambda_{s})$ and is suitable for radiometric PD wireless sensor nodes, where $\lambda_{s}$ is the wavelength of the lowest frequency of the band (i.e. 0.35 GHz). A stepped and beveled radiation patch is used in combination with a slotted ground plane to achieve a wide fractional bandwidth of 119% (0.35 to 1.38 GHz) for a return loss better than 10 dB. …

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Comparison Of Using The Genetic Algorithm And Cuckoo Search For Multicriteria Optimisation With Limitation, Ryszard Klempka, Boguslaw Filipowicz Jan 2017

Comparison Of Using The Genetic Algorithm And Cuckoo Search For Multicriteria Optimisation With Limitation, Ryszard Klempka, Boguslaw Filipowicz

Turkish Journal of Electrical Engineering and Computer Sciences

The article presents an example of using two optimisation methods, a genetic algorithm and cuckoo search, to identify parameters of electric drive controllers using some quality criteria and by applying a limitation to the maximum values of signals in the controlled facility. The results for both optimisation methods are compared. The impact of the probability that the nest host discovers the laid eggs on the speed of finding the optimum solution is investigated.

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Dual Broadband Antenna With Compact Double Ring Radiators For Ieee 802.11 Ac/B/G/N Wlan Communication Applications, Meri̇h Palandöken Jan 2017

Dual Broadband Antenna With Compact Double Ring Radiators For Ieee 802.11 Ac/B/G/N Wlan Communication Applications, Meri̇h Palandöken

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, a dual broadband antenna is proposed for WLAN communication modules supported by the IEEE 802.11 ac/b/g/n standard. The antenna design is based on two interspaced electrically small split-ring resonators, each of which is directly fed through the stepped impedance microstrip line with an optimized electromagnetic coupling distance in between. The proposed dual band antenna operates in the lower frequency band from 2.3 GHz up to 3 GHz with 2.65 GHz center frequency (26.4 % bandwidth) and in the higher frequency band from 4.7 GHz up to 6 GHz with 5.35 GHz center frequency (24.3% bandwidth). The radiating …

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Vector Control Of Unbalanced 3-Phase Im Using Forward And Backward Components, Mohammad Jannati, Nik Rumzi Nik Idris Jan 2017

Vector Control Of Unbalanced 3-Phase Im Using Forward And Backward Components, Mohammad Jannati, Nik Rumzi Nik Idris

Turkish Journal of Electrical Engineering and Computer Sciences

In some industries, continuous operation of 3-phase induction motors (IMs) even under faults until the scheduled maintenance time is essential. Conventional control techniques such as field-oriented control (FOC) cannot be used to control faulty IMs since this will result in significant oscillations in the speed and torque. Consequently, a new control approach must be developed for improving IM performance during fault conditions. This paper presents a method for vector control of 3-phase IMs under open-phase faults. The main advantage of this control scheme is its ability to handle not only one phase but also two phases of open-phase fault conditions. …

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Energy-Hole Avoidance And Lifetime Enhancement Of A Wsn Through Load Factor, Krishna Pal Sharma, Teek Parval Sharma Jan 2017

Energy-Hole Avoidance And Lifetime Enhancement Of A Wsn Through Load Factor, Krishna Pal Sharma, Teek Parval Sharma

Turkish Journal of Electrical Engineering and Computer Sciences

In wireless sensor networks, nonuniform communication load across a network often leads to the problem of energy holes or hot spots, i.e. nodes nearer high activity regions deplete their energy much faster than nodes elsewhere. This may partition the network into unreachable segments and thus adversely affect network lifetime. The problem is more acute in random and sparsely deployed networks. Therefore, we propose a deployment strategy that, using the least possible nodes, prolongs network lifetime by avoiding energy holes and also ensures full sensing and communication coverage. The scheme handles the energy imbalance by selecting an appropriate set of communication …

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Design And Realization Of A Novel Planar Array Antenna And Low Power Lna For Ku-Band Small Satellite Communications, Lida Kouhalvandi, Osman Ceylan, Selçuk Paker, Hasan Bülent Yağci Jan 2017

Design And Realization Of A Novel Planar Array Antenna And Low Power Lna For Ku-Band Small Satellite Communications, Lida Kouhalvandi, Osman Ceylan, Selçuk Paker, Hasan Bülent Yağci

Turkish Journal of Electrical Engineering and Computer Sciences

This article presents both a four-element novel microstrip array antenna and a low noise amplifier (LNA) for a Ku-band small satellite receiver. It includes all design details with measurement results of the fabricated array antenna and LNA. Measured minimum and maximum gains of the proposed antenna are 10.1 and 10.9 dBi in 11.9-12.9 GHz band frequency. The designed LNA has a noise figure lower than 1.5 dB and gain higher than 8 dB (at 2 V, 10 mA biasing). In order to reduce the design period and cost, discrete components are chosen and a hetero-junction FET is used as the …

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An Extremely Wideband Radome-Enclosed Cylindrical Dipole Antenna For Wireless Communication, Tariq Rahim, Jiadong Xu Jan 2017

An Extremely Wideband Radome-Enclosed Cylindrical Dipole Antenna For Wireless Communication, Tariq Rahim, Jiadong Xu

Turkish Journal of Electrical Engineering and Computer Sciences

A radome-enclosed extremely wideband cylindrical dipole antenna for wireless communications applications was proposed with a simple structure. The antenna is fed at the center with the help of a coaxial cable through the lower hollow metallic pole. The feed area is composed of cones at both sides in order to obtain wideband impedance matching. The proposed antenna can cover 1.8 GHz to 28 GHz with S11 of less than -10 dB and excellent stable omnidirectional radiation characteristics. However, at high frequencies, some ripples are introduced in the radiation pattern. The frequency band of the cylindrical dipole antenna can be controllable …

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Design And Operation Of A Multifunction Photovoltaic Power System With Shunt Active Filtering Using A Single-Stage Three-Phase Multilevel Inverter, Serkan Sezen, Ahmet Aktaş, Mehmet Uçar, Engi̇n Özdemi̇r Jan 2017

Design And Operation Of A Multifunction Photovoltaic Power System With Shunt Active Filtering Using A Single-Stage Three-Phase Multilevel Inverter, Serkan Sezen, Ahmet Aktaş, Mehmet Uçar, Engi̇n Özdemi̇r

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, the control of a multifunction grid-connected photovoltaic (PV) system with a three-phase three-level (3L) neutral point clamped (NPC) inverter is proposed, which can perform shunt active filtering. Normally, the shunt active filtering is achieved by detecting the harmonic and reactive currents of the nonlinear load and then injecting the compensating current into the grid. Therefore, the proposed system can inject PV power to a grid with power factor correction and current harmonic filtering features simultaneously. In addition, a single-stage compact and efficient transformerless power conversion topology is used in this paper for the grid-connected solar PV system …

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Effect Of Micro/Nano-Sio$_{2}$ On Mechanical, Thermal, And Electrical Properties Of Silicone Rubber, Epoxy, And Epdm Composites For Outdoor Electrical Insulations, Hidayatullah Khan, Muhammad Amin, Muhammad Ali, Muhammad Iqbal, Muhammad Yasin Jan 2017

Effect Of Micro/Nano-Sio$_{2}$ On Mechanical, Thermal, And Electrical Properties Of Silicone Rubber, Epoxy, And Epdm Composites For Outdoor Electrical Insulations, Hidayatullah Khan, Muhammad Amin, Muhammad Ali, Muhammad Iqbal, Muhammad Yasin

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper the influence of micro-sized (3 $\mu $m) and nano-sized (10 nm) silica (SiO$_{2})$ on mechanical, thermal, and electrical properties of silicon rubber (SiR), epoxy, and ethylene propylene diene monomer (EPDM) composites is presented. The micro- and nano-sized SiO$_{2}$ particle-filled SiR, epoxy, and EPDM composites were formulated with 20% microsilica and 5% nanosilica by weight respectively. Among these composites, SiR-SiO$_{2}$ amalgamation was performed by mixing using an ultrasonication procedure. Epoxy-SiO$_{2}$ was compounded in two steps, i.e. dispersion of fillers and mixing, whereas EPDM-SiO$_{2}$ compounding was performed with a two roll mill technique. With the addition of micro/nano-SiO$_{2}$, the …

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A Cell-Based 5-Mhz On-Chip Clock Generator, Ching-Che Chung, Jhih-Wei Li Jan 2017

A Cell-Based 5-Mhz On-Chip Clock Generator, Ching-Che Chung, Jhih-Wei Li

Turkish Journal of Electrical Engineering and Computer Sciences

A cell-based 5-MHz on-chip clock generator for smart sensing applications is presented. By exploiting relative reference modeling, our proposed design can dynamically track both voltage and temperature variations after four-point chip calibrations. The proposed on-chip clock generator is fabricated using a 90-nm CMOS process, the frequency stability is 160 ppm/$^{\circ}$C and 72 ppm/mV over 0 $^{\circ}$C to 75 $^{\circ}$C and 0.9 V to 1.1 V, and the settling time of the proposed on-chip clock generator is 5.12 $\mu$s. The proposed on-chip clock generator was implemented with standard cells that can greatly reduce the design complexity and design time for on-chip …

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Whole Body Motion Control Of Humanoid Robots Using Bilateral Control, Emre Sariyildiz, Hakan Temeltaş Jan 2017

Whole Body Motion Control Of Humanoid Robots Using Bilateral Control, Emre Sariyildiz, Hakan Temeltaş

Turkish Journal of Electrical Engineering and Computer Sciences

This paper deals with the whole body motion control problem of humanoid robots by using automatic and bilateral control methods. Advanced motion controllers are proposed so that human daily life activities, such as walking on an uneven terrain and contacting an unknown object, can be performed. It is shown that the uncertainty of environmental impedance variation is one of the main challenging issues in the design of the automatic control systems, i.e. a humanoid robot may easily lose its stability when it contacts an unstructured environment. A novel bilateral control method is proposed for humanoid robots so as to overcome …

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Design And Test Of A New Development Fpga Board For Mobile Robot Research, Baligh Naji, Chokri Abdelmoula, Karim Abbes, Mohamed Masmoudi Jan 2017

Design And Test Of A New Development Fpga Board For Mobile Robot Research, Baligh Naji, Chokri Abdelmoula, Karim Abbes, Mohamed Masmoudi

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents the design and testing of a newly developed field programmable gate array (FPGA) board for mobile robot research. The idea consists of interfacing the FPGA to a 16-bit digital signal controller (dsPIC). This idea enables the FPGA designs to communicate with the dsPIC through the integration of per-written driver modules to be used in a wide variety of digital and analog peripheral modules. It also allows the use of a high-performance digital signal processing core in many signal processing-based mobile robot applications. The proposed FPGA board allows users to develop, test, and deploy quick and cost-effective complete …

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Early Detection Of Sudden Cardiac Death Using Poincaré Plots And Recurrence Plot-Based Features From Hrv Signals, Vahid Houshyarifar, Mehdi Chehel Amirani Jan 2017

Early Detection Of Sudden Cardiac Death Using Poincaré Plots And Recurrence Plot-Based Features From Hrv Signals, Vahid Houshyarifar, Mehdi Chehel Amirani

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper we present a method to predict sudden cardiac death (SCD) based on the heart rate variability (HRV) signal and recurrence plots and Poincaré plot-extracted features. This work is a challenge since it is aimed to devise a method to predict SCD 5 min before its onset. The method consists of four steps: preprocessing, feature extraction, feature reduction, and classification. In the first step, the QRS complexes are detected from the electrocardiogram signal and then the HRV signal is extracted. In the second step, the recurrence plot of the HRV signal and Poincaré plot-extracted features are obtained. Four …

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Communications Protocol For Power Management In Smart Homes, Milan Bjelica, Mirjana Simic Pejovic Jan 2017

Communications Protocol For Power Management In Smart Homes, Milan Bjelica, Mirjana Simic Pejovic

Turkish Journal of Electrical Engineering and Computer Sciences

Emergency situations, incentives for energy efficiency, new pricing plans, and distributed electricity market jointly require home automation systems that would conform an instantaneous load to a dynamically set limit. In this paper, a novel machine-to-machine communications protocol that interconnects a smart grid and smart house is described. ''Intelligent'' domestic appliances use it to coordinate their switch-on times so that the assigned power quota will not be exceeded. In this way, the end-user experience can be improved by reducing the electricity bills, conveniently conforming to prepaid pricing plans, or even by providing continued service at possibly reduced consumption levels during power …

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Comparing Of Phase Shifting Method And One-Dimensional Continuous Wavelet Transform Method For Reconstruction Using Phase-Only Information, Gülhan Ustabaş Kaya, Zehra Saraç Jan 2017

Comparing Of Phase Shifting Method And One-Dimensional Continuous Wavelet Transform Method For Reconstruction Using Phase-Only Information, Gülhan Ustabaş Kaya, Zehra Saraç

Turkish Journal of Electrical Engineering and Computer Sciences

The one-dimensional continuous wavelet transform method has some advantages in hologram reconstruction, when used in the only phase, compared with the phase shifting method. This paper aims to discuss these advantages. One advantage is related to image quality. Another advantage is less power spent and saving time, because the one-dimensional continuous wavelet transform method uses only one hologram and the phase shifting method uses four holograms for recording and reconstruction processes. One final advantage is that the one-dimensional continuous wavelet transform method can also be used in real-time applications. Within the context of the ongoing optimization studies, this study will …

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Comparative Study Of Conventional Modulation Schemes In Terms Of Conducted And Radiated Emi Generated By Three-Phase Inverters, Mohamed Salem, Mahmoud Hamouda, Jaleleddine Ben Hadj Slama Jan 2017

Comparative Study Of Conventional Modulation Schemes In Terms Of Conducted And Radiated Emi Generated By Three-Phase Inverters, Mohamed Salem, Mahmoud Hamouda, Jaleleddine Ben Hadj Slama

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, a comparative study is carried out between the carrier (SPWM), third harmonic injection (THIPWM), and space vector (SVPWM) modulation schemes in terms of conducted (common and differential modes) and radiated electromagnetic interference (EMI) generated by three-phase two-level voltage source inverters. For this purpose, an experimental setup of the converter feeding an induction machine is developed with the aim to measure the conducted emission propagated back into the dc source and the radiated field in the vicinity of the power conversion device. Experimental results are given and analyzed in time and frequency domains. The comparative study between the …

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Assignment As A Location-Based Service In Outsourced Databases, Ahmet Sali̇h Büyükkayhan, Taflan İmre Gündem Jan 2017

Assignment As A Location-Based Service In Outsourced Databases, Ahmet Sali̇h Büyükkayhan, Taflan İmre Gündem

Turkish Journal of Electrical Engineering and Computer Sciences

Location-based services provide opportunities to organizations for tracking and utilizing their resources. Moreover, some corporations prefer to outsource their database management services. In the literature, privacy preservation techniques in outsourced spatial databases for several query types, such as nearest neighbor, K-nearest neighbor, and proximity search, have been examined. In this paper, we present an efficient application of the capacity and coverage-constrained assignment query on outsourced spatial databases. In the proposed technique, we introduce a novel spatial transformation strategy (square spiral encoding) to achieve privacy efficiently for approximate assignment query results. To process the assignment query, we use the parallel auction …

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Design Of A Self-Starting Hybrid Permanent Magnet Hysteresis Synchronous Motor Connected Directly To The Grid, Mehmet Gedi̇kpinar, Ömür Aydoğmuş Jan 2017

Design Of A Self-Starting Hybrid Permanent Magnet Hysteresis Synchronous Motor Connected Directly To The Grid, Mehmet Gedi̇kpinar, Ömür Aydoğmuş

Turkish Journal of Electrical Engineering and Computer Sciences

In this work, a permanent magnet hysteresis synchronous (PMHS) motor was designed to improve the efficiency of the system. The proposed motor is intended for pumping applications, such as submersible pump motors, fire pumps, oil-well pumps, and circulation pumps requiring high-speed operation. The efficiency of the pump system increases depending on the speed of the pump fans. The total efficiency of the pump system is reduced because the load increases exponentially in these types of application systems. The speed is important for the pumping applications in order to improve the efficiency of the pump system. Nowadays, traditional induction motors are …

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Training Anfis By Using The Artificial Bee Colony Algorithm, Dervi̇ş Karaboğa, Ebubeki̇r Kaya Jan 2017

Training Anfis By Using The Artificial Bee Colony Algorithm, Dervi̇ş Karaboğa, Ebubeki̇r Kaya

Turkish Journal of Electrical Engineering and Computer Sciences

In this study, a new adaptive network-based fuzzy inference system (ANFIS) training algorithm, the artificial bee colony (ABC) algorithm, is presented. Antecedent and conclusion parameters existing in the structure of ANFIS are optimized with the ABC algorithm and ANFIS training is realized. Identification of a set of nonlinear dynamic systems is performed in order to analyze the suggested training algorithm. The ABC algorithm is operated 30 times for each identification case and the average root mean square error (RMSE) value is obtained. Training RMSE values calculated for the four examples considered are 0.0325, 0.0215, 0.0174, and 0.0294, respectively. In addition, …

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Research On Magnetic Field State Analysis Of A Nonsalient Pole Synchronous Generator, Baojun Ge, Pin Lv, Dajun Tao, Fang Xiao, Hongsen Zhao Jan 2017

Research On Magnetic Field State Analysis Of A Nonsalient Pole Synchronous Generator, Baojun Ge, Pin Lv, Dajun Tao, Fang Xiao, Hongsen Zhao

Turkish Journal of Electrical Engineering and Computer Sciences

This paper is based on the definition of minor asymmetric degree and the relative position of the magnetic field. The relative position of the magnetic field is the angle between the positive and negative sequence magnetic fields. The corresponding relationship between the nonsalient pole synchronous generator steady performance and the magnetic field state is discussed when the generator operates at minor asymmetry. To analyze this corresponding relationship, the Taylor expansion formula with Lagrange remainder and symmetrical components is adopted. We study the relationship between the armature current and the relative position of the magnetic field, deducing the armature current expressions …

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Loss Minimization In Wind Farm Integrated Ac/Dc System By Optimal Injections And Droop Settings Of Vsc-Mtdc Systems, Anbuselvi Shanmugam Velu, Somasundaram Periyasamy, Kumudini Devi Raguru Pandu Jan 2017

Loss Minimization In Wind Farm Integrated Ac/Dc System By Optimal Injections And Droop Settings Of Vsc-Mtdc Systems, Anbuselvi Shanmugam Velu, Somasundaram Periyasamy, Kumudini Devi Raguru Pandu

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, a modified optimal power flow (OPF) model, incorporating a voltage source converter-based multiterminal DC (VSC-MTDC) system, is proposed. The OPF is formulated to minimize the losses, steady state voltage deviations, and overloading of the AC/DC system. The control variables considered in this modified OPF model are power injection into the DC system and droop settings. Optimal injection patterns for different wind power penetrations and optimal droop settings are evaluated for wind farm side converters and grid side converters, respectively. Wind power penetrations are routed into AC and DC lines in different proportions to optimize the flows in …

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Ionolab-Ray: A Wave Propagation Algorithm For Anisotropic And Inhomogeneous Ionosphere, Esra Erdem, Feza Arikan Jan 2017

Ionolab-Ray: A Wave Propagation Algorithm For Anisotropic And Inhomogeneous Ionosphere, Esra Erdem, Feza Arikan

Turkish Journal of Electrical Engineering and Computer Sciences

A high-frequency (HF) radio wave propagation model based on ray tracing for anisotropic, inhomogeneous, and time-varying ionosphere is developed to form the basis for a user-friendly modular algorithm. The algorithm IONOLAB-RAY applies the principles of ray tracing through the spherical 3D grid model of the ionosphere. The physical parameters of the ionosphere in each voxel are obtained from the ionosphere model IRI-Plas-G. The refractive index of each voxel is calculated with the Appleton-Hartree formula, which includes electron cyclotron frequency, collision frequency, and anisotropicity due to the geomagnetic field. The developed propagation algorithm allows the input of total electron content (TEC) …

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Effect Of Touch Coordinate Display As A Form Of Augmented, Concurrent Visual Feedback On The Accuracy Of Single-Handed Typing Via Smartphone Virtual Keyboards, Abdullah Ruhi̇ Soylu, Görkem Yavaş, Bora Ergi̇n, Sumru Keçeli̇ Jan 2017

Effect Of Touch Coordinate Display As A Form Of Augmented, Concurrent Visual Feedback On The Accuracy Of Single-Handed Typing Via Smartphone Virtual Keyboards, Abdullah Ruhi̇ Soylu, Görkem Yavaş, Bora Ergi̇n, Sumru Keçeli̇

Turkish Journal of Electrical Engineering and Computer Sciences

This study assessed the effect of an easily perceived real-time visual feedback method on touchscreen typing accuracy. Thirty subjects were asked to hold a smartphone with a capacitive touchscreen in one hand and enter a text using the thumb of the same hand via a custom designed virtual keyboard. There were two types of text entry sessions: with or without visual feedback. The visual feedback consisted of a full-screen crosshair, representing the accurate coordinate of touch in real time. In each session, touch-down time on the virtual keyboard and touch coordinates were recorded for every touch action. Two types of …

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