Real-Time Motorized Electrical Hospital Bed Control With Eye-Gaze Tracking,
2016
TÜBİTAK
Real-Time Motorized Electrical Hospital Bed Control With Eye-Gaze Tracking, Nesri̇n Aydin Atasoy, Abdullah Çavuşoğlu, Ferhat Atasoy
Turkish Journal of Electrical Engineering and Computer Sciences
Patients with motor neuron disease and most terminal patients cannot use their hands or arms, and so they need another person for their all needs. However, the mental functions and memories of such patients are generally sound, and they can control their eyes. Using an eye-gaze tracking technique, we have realized a real-time system for such patients. The system controls a motorized electrical hospital bed (EHB) by eye gaze with 4 degrees of freedom, using a low-cost webcam. Contactless systems that require calibration cannot be used for EHB control. The system developed in this work does not require any calibration …
Thermal Aging Of Solid Insulation Under Dual Temperature Variation,
2016
TÜBİTAK
Thermal Aging Of Solid Insulation Under Dual Temperature Variation, Amit Kumar Mehta, Ram Naresh Sharma, Sushil Chauhan
Turkish Journal of Electrical Engineering and Computer Sciences
The power transformer is one of the most expensive pieces of equipment in a high-voltage AC power system. An adequate monitoring system for power transformers can help in reducing the failure rate and thereby enhance system reliability and economic efficiency. Long-term and accelerated aging is not possible in real transformers, so prorated models of real transformers are preferred. This paper presents a study aimed at the aging of different cellulose papers and pressboards impregnated with transformer oil subjected to accelerated thermal aging at an oil temperature of 120 $^{\circ}$C and winding temperature of 150 $^{\circ}$C for time intervals extending from …
Dynamic Characteristics Of An Isolated Self-Excited Synchronous Reluctance Generator Driven By A Wind Turbine,
2016
TÜBİTAK
Dynamic Characteristics Of An Isolated Self-Excited Synchronous Reluctance Generator Driven By A Wind Turbine, Mosaad Mohiedden Ali, Said Mahmoud Allam, Talaat Hamdan Abdel-Moneim
Turkish Journal of Electrical Engineering and Computer Sciences
This paper studies the dynamic characteristics of an isolated three-phase self-excited synchronous reluctance generator (SESRG) driven by a variable-speed wind turbine under different operating conditions. Self-excitation is achieved via capacitors connected across the generator terminals. A detailed mathematical modeling of the proposed self-excited wind generation system is presented. The proposed analysis is based on the dynamic qd-axis model of the SESRG. Magnetic saturation is taken into account and is assumed to be confined to the direct axis and is accounted for as a variable direct-axis magnetizing reactance. Effect of wind-speed variation, excitation-capacitance variation, and loading-conditions variation on the generated output …
Towards A Semantic-Based Information Extraction System For Matching Résumés To Job Openings,
2016
TÜBİTAK
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 …
The Classification Of Eeg Signals Using Discretization-Based Entropy And The Adaptive Neuro-Fuzzy Inference System,
2016
TÜBİTAK
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 …
Optimal Power Flow With Svc Devices By Using The Artificial Bee Colony Algorithm,
2016
TÜBİTAK
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 …
Linear Model Of A Three-Phase Shunt Active Power Filter With A Hysteresis Controller,
2016
TÜBİTAK
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 …
Improving The Srf Method To Compensate Low-Order Harmonics Under Nonsinusoidal Network Voltages,
2016
TÜBİTAK
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. …
Empirical Mode Decomposition Application For Short-Term Flicker Severity,
2016
TÜBİTAK
Empirical Mode Decomposition Application For Short-Term Flicker Severity, Yasemi̇n Önal, Ömer Nezi̇h Gerek, Doğan Gökhan Ece
Turkish Journal of Electrical Engineering and Computer Sciences
In this article, an approach based on empirical mode decomposition (EMD) is suggested in order to calculate short-term flicker severity, Pst, in power systems. EMD is a new signal processing method used for the analysis of nonlinear and nonstationary signals. Pst is an important quantity in the electric power quality index defined by the International Electrotechnical Commission. In the suggested approach, the voltage signal is separated into intrinsic mode function components using EMD. These components are used for calculating the voltage flicker amplitude and frequency, and Pst is calculated as a result of the statistical evaluation of flicker amplitude. EMD …
An Improved Real-Time Adaptive Kalman Filter With Recursive Noise Covariance Updating Rules,
2016
TÜBİTAK
An Improved Real-Time Adaptive Kalman Filter With Recursive Noise Covariance Updating Rules, Iyad Hashlamon, Kemaletti̇n Erbatur
Turkish Journal of Electrical Engineering and Computer Sciences
The Kalman filter (KF) is used extensively for state estimation. Among its requirements are the process and observation noise covariances, which are unknown or partially known in real-life applications. Uncertain and biased values of the covariances result in KF performance degradation or divergence. Unlike previous methods, we are using the idea of the recursive estimation of the KF to develop two recursive updating rules for the process and observation covariances, respectively designed based on the covariance matching principles. Each rule has a tuning parameter that enhances its flexibility for noise adaptation. The proposed adaptive Kalman filter (AKF) proves itself to …
Passivity-Based Robust Controller Design For A Variable Speed Wind Energy Conversion System,
2016
TÜBİTAK
Passivity-Based Robust Controller Design For A Variable Speed Wind Energy Conversion System, Peng Wang, Haisong Wang, Xu Cai, Zhengzhi Han
Turkish Journal of Electrical Engineering and Computer Sciences
This paper proposes a design method for a robust controller to improve the stability and system dynamic behavior for variable speed wind energy conversion systems. By analyzing the mathematical model of a wind power conversion system, control strategies for both a generator-side converter and a grid-side converter are given. For the generator-side converter, the well-known maximum power point tracking method is employed, while for the grid-side converter, a robust controller is presented based on passivity theory. The $L_{2}$-gain performance is analyzed using linear matrix inequality. Moreover, in order to accelerate the dynamic response and reduce the DC link voltage fluctuations, …
A 2.4-Ghz Highly Linear Derivative Superposition Gilbert Cell Mixer,
2016
TÜBİTAK
A 2.4-Ghz Highly Linear Derivative Superposition Gilbert Cell Mixer, Samaneh Sedighi, Omid Hashemipour, Massoud Dousti
Turkish Journal of Electrical Engineering and Computer Sciences
This paper presents a new derivative superposition Gilbert cell to minimize the third-order nonlinear current term of transconductance transistors. To decrease the parasitic capacitance effect on gain, noise figure, and linearity of the circuit, extra inductors and capacitors are added between the switching and transconductance stages. The proposed mixer is simulated in 0.18-$\mu $m RF-CMOS technology with a 1.8-V supply. The results show an improvement of about 23 dBm in IIP3 compared to conventional mixers. The power consumption of this circuit is about 3.96 mW.
Research On Switched Reluctance Machine Drive Topology And Control Strategies For Electric Vehicles,
2016
TÜBİTAK
Research On Switched Reluctance Machine Drive Topology And Control Strategies For Electric Vehicles, He Cheng, Hao Chen, Lei Ma, Guojun Yu
Turkish Journal of Electrical Engineering and Computer Sciences
The electric drive system is one of the key technologies for electric vehicles. First, the energy flow of an electric vehicle is analyzed in the driving, braking, and charging working states. After that, a drive topology that can achieve 3 working states is proposed based on the driving characteristics of a switched reluctance machine. In the driving state, the boost mode of a front-end converter is used to achieve different operating conditions, including low speed with a light load or high speed with a heavy load. In the braking state, the front-end converter is used to implement smooth switching between …
Solving Multimodal Optimization Problems Based On Efficient Partitioning Of Genotypic Search Space,
2016
TÜBİTAK
Solving Multimodal Optimization Problems Based On Efficient Partitioning Of Genotypic Search Space, Atabak Mashhadi Kashtiban, Sohrab Khanmohammadi, Kayvan Asghari
Turkish Journal of Electrical Engineering and Computer Sciences
Enhancing the exploration and exploitation of multimodal optimization is still an interesting and challenging problem in optimization. Here we present a new population-based evolutionary algorithm for multiple optimal determinations. The approach is simply based on partitioning the genotypic search space and running a simple genetic algorithm with a small population within each partition. To increase the efficiency of the algorithm, the first-order discrete derivative of the fitness function for elite solutions was used to omit extra solutions. If the derivative of the fitness function is larger than a specified gradient threshold, no optimum exists within a given partition, and no …
A New Cmos Zc-Cdta Realization And Its Filter Applications,
2016
TÜBİTAK
A New Cmos Zc-Cdta Realization And Its Filter Applications, Ersi̇n Alaybeyoğlu, Hulusi̇ Hakan Kuntman
Turkish Journal of Electrical Engineering and Computer Sciences
The Z copy current differencing transconductance amplifier (ZC-CDTA) is a new current-mode active element that was introduced recently. ZC-CDTA is improved from the current differencing transconductance amplifier (CDTA) and has increased its universality. In the current study, a CMOS implementation of ZC-CDTA is proposed. The first stage of ZC-CDTA consists of a current differencing unit. The output stage consists of a dual output transconductance amplifier. Furthermore, a third-generation current conveyor is used to copy the Z terminal current instead of a classical current mirror. A fourth-order filter application employing ZC-CDTAs is given and simulation results are added. The ZC-CDTA-based filter …
Design And Implementation Of A Man-Overboard Emergency Discovery System Based On Wireless Sensor Networks,
2016
TÜBİTAK
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 …
Walsh Series Modeling And Estimation In Sensorless Position Control Of Electrical Drives,
2016
TÜBİTAK
Walsh Series Modeling And Estimation In Sensorless Position Control Of Electrical Drives, Hamidreza Shirazi, Jalal Nazarzadeh
Turkish Journal of Electrical Engineering and Computer Sciences
High-performance electrical drives can be achieved by using field-oriented controllers, which make torque and flux naturally decoupled. A conventional vector-controlled drive has the disadvantage of either requiring flux and speed sensors or being affected by rotor resistance, which varies along with the motor performance. The presented paper focuses on developing a high-performance sensorless rotor flux-oriented controller of an induction machine independent of the rotor resistance variation. This method applies spectral theory of Walsh functions, which are one of the most helpful members of piecewise constant basis functions in solving dynamic models. Inherent characteristics of Walsh functions and application of an …
Quantitative Information Extraction From Gas Sensor Data Using Principal Component Regression,
2016
TÜBİTAK
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 …
Development Of Radiometer Operating Between 50 Mhz And 26.5 Ghz Using Gain-Stabilized Lna,
2016
TÜBİTAK
Development Of Radiometer Operating Between 50 Mhz And 26.5 Ghz Using Gain-Stabilized Lna, Murat Celep, Şenel Yaran, Cem Hayirli, Ari̇f Dolma
Turkish Journal of Electrical Engineering and Computer Sciences
A radiometer operating between 50 MHz and 26.5 GHz and consisting of microwave channels all with a low-noise amplifier (LNA) was established. Microwave switches were used to select an appropriate channel according to measurement frequency. The effect of variations both in input and output reflection coefficients on LNA gain was investigated. To keep the change in the gain of the LNA at minimum, the LNA output was terminated with a load whose impedance was equal to that of matched load. This technique gives the opportunity of full-band noise measurements of noise sources with one total power radiometer. The performance of …
Performance Analysis Of Biogeography-Based Optimization For Automatic Voltage Regulator System,
2016
TÜBİTAK
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 …
