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2011

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Articles 121 - 135 of 135

Full-Text Articles in Computer Engineering

A New, Improved Cmos Realization Of Cdta And Its Filter Applications, Firat Kaçar, Hulusi̇ Hakan Kuntman Jan 2011

A New, Improved Cmos Realization Of Cdta And Its Filter Applications, Firat Kaçar, Hulusi̇ Hakan Kuntman

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a high-performance current differencing transconductance amplifier (CDTA), a recently reported active element, especially suitable for analog signal processing applications. A high linearity CMOS configuration for a CDTA is made up of high linearity input and output stages. The proposed CDTA provides high output impedance at port X and excellent input/output current tracking. A biquad filter circuit was chosen as an application example in order to demonstrate the performance of the CDTA. PSpice simulation results using a TSMC 0.35-\mu m CMOS process model were included to verify the expected values.


A Logic Method For Efficient Reduction Of The Space Complexity Of The Attribute Reduction Problem, Mehmet Hacibeyoğlu, Fati̇h Başçi̇ftçi̇, Şi̇rzat Kahramanli Jan 2011

A Logic Method For Efficient Reduction Of The Space Complexity Of The Attribute Reduction Problem, Mehmet Hacibeyoğlu, Fati̇h Başçi̇ftçi̇, Şi̇rzat Kahramanli

Turkish Journal of Electrical Engineering and Computer Sciences

The goal of attribute reduction is to find a minimal subset (MS) R of the condition attribute set C of a dataset such that R has the same classification power as C. It was proved that the number of MSs for a dataset with n attributes may be as large as (_{n/2}^n) and the generation of all of them is an NP-hard problem. The main reason for this is the intractable space complexity of the conversion of the discernibility function (DF) of a dataset to the disjunctive normal form (DNF). Our analysis of many DF-to-DNF conversion processes showed that approximately …


Fully Parallel Ann-Based Arrhythmia Classifier On A Single-Chip Fpga: Fpaac, Ahmet Turan Özdemi̇r, Kenan Danişman Jan 2011

Fully Parallel Ann-Based Arrhythmia Classifier On A Single-Chip Fpga: Fpaac, Ahmet Turan Özdemi̇r, Kenan Danişman

Turkish Journal of Electrical Engineering and Computer Sciences

Recognition of cardiac arrhythmias by electrocardiogram (ECG) is an important issue for diagnosis of cardiac abnormalities. Many studies on recognition of cardiac arrhythmias by ECG, using various techniques, have been performed in the past 20 years. Artificial neural networks (ANNs) are the most widely used tool in medical diagnosis systems (MDS) because of their powerful prediction characteristics. An ANN model is inspired by real biological neural networks, with a parallel structure that is potentially fast for computation. However, the suggested ANN architectures in the literature can only be run sequentially, on powerful processors, due to their complexity. Our approach enables …


Learning Control Of Robot Manipulators In The Presence Of Additive Disturbances, Enver Tatlicioğlu Jan 2011

Learning Control Of Robot Manipulators In The Presence Of Additive Disturbances, Enver Tatlicioğlu

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, a learning controller for robot manipulators is developed. The controller is proven to yield in a semi-global asymptotic result in the presence of additive input and output disturbances. Lyapunov-based techniques are used to guarantee that the tracking error is asymptotically driven to zero. Numerical simulation results are presented to demonstrate the viability of the proposed learning controller.


Design And Control Of The Humanoid Robot Suralp, Kemaletti̇n Erbatur, Utku Seven, Evri̇m Taşkiran, Özer Koca, Meti̇n Yilmaz, Mustafa Ünel, Güllü Kiziltaş Şendur, Asif Sabanovic, Ahmet Onat Jan 2011

Design And Control Of The Humanoid Robot Suralp, Kemaletti̇n Erbatur, Utku Seven, Evri̇m Taşkiran, Özer Koca, Meti̇n Yilmaz, Mustafa Ünel, Güllü Kiziltaş Şendur, Asif Sabanovic, Ahmet Onat

Turkish Journal of Electrical Engineering and Computer Sciences

SURALP is a 29 degrees-of-freedom full-body walking humanoid robot designed and constructed at Sabanci University - Turkey. The human-sized robot is actuated by DC motors, belt and pulley systems and Harmonic Drive reduction gears. The sensory equipment consists of joint encoders, force/torque sensors, inertial measurement systems and cameras. The control hardware is based on a dSpace digital signal processor. This paper reviews the design of this robot and presents experimental walking results. A posture zeroing procedure is followed after manual zeroing of the robot joints. Controllers for landing impact reduction, early landing trajectory modification, foot-ground orientation compliance, body inclination and …


Design And Development Of A Tilt-Wing Uav, Ertuğrul Çeti̇nsoy, Efe Sirimoğlu, Kaan Taha Öner, Cevdet Hançer, Mustafa Ünel, Mahmut Faruk Akşi̇t, İlyas Kandemi̇r, Kayhan Gülez Jan 2011

Design And Development Of A Tilt-Wing Uav, Ertuğrul Çeti̇nsoy, Efe Sirimoğlu, Kaan Taha Öner, Cevdet Hançer, Mustafa Ünel, Mahmut Faruk Akşi̇t, İlyas Kandemi̇r, Kayhan Gülez

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, the mechanical and aerodynamic design, carbon composite production, hierarchical control system design and vertical flight tests of a new unmanned aerial vehicle (UAV), which is capable of VTOL (vertical takeoff and landing) like a helicopter and long range horizontal flight like an airplane, are presented. Real flight tests show that the aerial vehicle can successfully operate in VTOL mode. Kalman filtering is employed to obtain accurate roll and pitch angle estimations.


Spoiler Effects Reduction With Using Active Power Filter On A Direct Torque Controlled Induction Machine, İbrahi̇m Alişkan, Kayhan Gülez, Yusuf Altun Jan 2011

Spoiler Effects Reduction With Using Active Power Filter On A Direct Torque Controlled Induction Machine, İbrahi̇m Alişkan, Kayhan Gülez, Yusuf Altun

Turkish Journal of Electrical Engineering and Computer Sciences

Harmonics, which may be placed in electrical systems, have important effects on performance parameters of electrical motors. In this paper, effects of electrical power system voltage harmonics on torque position of induction motors are dealt with. System modeling with Pulse Width Modulation (PWM) type Active Power Filter (APF) is used for reducing these effects. APF, as a subsystem, is placed into torque control system entrance to save the control system and induction motor output torque. Motor outputs, that are before-after APF connections, are handed for understanding effects of voltage harmonics. Since APF design was based on voltage harmonics, Electromagnetic Interference …


Vibrations Control Of Light Rail Transportation Vehicle Via Pid Type Fuzzy Controller Using Parameters Adaptive Method, Muzaffer Meti̇n, Rahmi̇ Güçlü Jan 2011

Vibrations Control Of Light Rail Transportation Vehicle Via Pid Type Fuzzy Controller Using Parameters Adaptive Method, Muzaffer Meti̇n, Rahmi̇ Güçlü

Turkish Journal of Electrical Engineering and Computer Sciences

In this study, a conventional PID type fuzzy controller and parameter adaptive fuzzy controller are designed to control vibrations actively of a light rail transport vehicle which modeled as 6 degree-of-freedom system and compared performances of these two controllers. Rail vehicle model consists of a passenger seat and its suspension system, vehicle body, bogie, primary and secondary suspensions and wheels. The similarity between mathematical model and real system is shown by comparing uncontrolled simulation results and vibration measurements. For carrying a comfortable travel, rail vehicle body and passenger seat vibrations are minimized by adding a controller between rail vehicle body …


Active Vibration Control Of Seismic Excited Structural System Using Lmi-Based Mixed H_2/H_{\Infty} State Feedback Controller, Hakan Yazici, Rahmi̇ Güçlü Jan 2011

Active Vibration Control Of Seismic Excited Structural System Using Lmi-Based Mixed H_2/H_{\Infty} State Feedback Controller, Hakan Yazici, Rahmi̇ Güçlü

Turkish Journal of Electrical Engineering and Computer Sciences

This paper is concerned with the active vibration control of a four-degree-of-freedom structure, which is effected by earthquake. To obtain desired time history and frequency responses for solution of active vibration control problem, Linear Matrix Inequality (LMI) based state-feedback mixed H_2/H_{\infty} controller is designed in this study. The time history of ground motion of the Kobe earthquake in 1995, which is a disturbance input, is applied to modeled structure. At the end of the study, the time history of the storey displacements, velocities and frequency responses of both controlled and uncontrolled cases are presented and results are discussed. Performance of …


Delay Compensation In Bilateral Control Using A Sliding Mode Observer, Tuğba Leblebi̇ci̇, Berk Çalli, Mustafa Ünel, Asif Sabanovic, Seta Bogosyan, Meti̇n Gökaşan Jan 2011

Delay Compensation In Bilateral Control Using A Sliding Mode Observer, Tuğba Leblebi̇ci̇, Berk Çalli, Mustafa Ünel, Asif Sabanovic, Seta Bogosyan, Meti̇n Gökaşan

Turkish Journal of Electrical Engineering and Computer Sciences

In bilateral control applications, time delays in the communication channel have destabilizing effects and cause degradations in the performance of the system. In this paper, a sliding mode observer is used in conjunction with a disturbance observer to predict states of the slave system. Predicted states are then used in control formulation. Simulation and experimental results show that the proposed method avoids instability due to time delays in bilateral operation and provides satisfactory performance.


Induction Motor, State Estimation, Extended Kalman Filtering, Recurrent Neural Networks, Saadetti̇n Aksoy, Aydin Mühürcü Jan 2011

Induction Motor, State Estimation, Extended Kalman Filtering, Recurrent Neural Networks, Saadetti̇n Aksoy, Aydin Mühürcü

Turkish Journal of Electrical Engineering and Computer Sciences

This study presents a recurrent neural network (RNN)-based nonlinear state estimator that uses an Elman neural network structure (ENN) for state estimation of a squirrel-cage induction motor. The proposed algorithm only uses the measurements of the stator currents and the rotor angular speed, and it learns the dynamic behavior of the state observer from these measurements through prediction error minimization. A squirrel-cage induction motor was fed from sinusoidal, 6-step, and pulse-width modulation (PWM) supply sources at different times in order to observe the performance of the proposed estimator for different operation conditions. Estimation results showed that the proposed algorithm is …


A Luenberger-Sliding Mode Observer With Rotor Time Constant Parameter Estimation In Induction Motor Drives, Mustafa Gürkan Aydeni̇z, İbrahi̇m Şenol Jan 2011

A Luenberger-Sliding Mode Observer With Rotor Time Constant Parameter Estimation In Induction Motor Drives, Mustafa Gürkan Aydeni̇z, İbrahi̇m Şenol

Turkish Journal of Electrical Engineering and Computer Sciences

The performance and efficiency of an induction motor drive system can be enhanced by online estimation of critical parameters such as rotor time constant. A novel Luenberger-sliding mode observer with a parameter adaptation algorithm is proposed in this paper to compensate for the parameter variation effects. The observer is comparably simple and robust relative to the previously developed observers, and yet suitable for online implementation. Simulation studies for the proposed method were conducted in a MATLAB environment. Observer constants and the control parameters were tuned during the simulation studies and used during the experimental study stage. Experimental verification of the …


An Algorithm To Minimize Within-Class Scatter And To Reduce Common Matrix Dimension For Image Recognition, Ümi̇t Çi̇ğdem Turhal, Alpaslan Duysak Jan 2011

An Algorithm To Minimize Within-Class Scatter And To Reduce Common Matrix Dimension For Image Recognition, Ümi̇t Çi̇ğdem Turhal, Alpaslan Duysak

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, a new algorithm using 2DPCA and Gram-Schmidt Orthogonalization Procedure for recognition of face images is proposed. The algorithm consists of two parts. In the first part, a common feature matrix is obtained; and in the second part, the dimension of the common feature matrix is reduced. Resulting common feature matrix with reduced dimension is used for face recognition. Column and row covariance matrices are obtained by applying 2DPCA on the column and row vectors of images, respectively. The algorithm then applies eigenvalue-eigenvector decomposition to each of these two covariance matrices. Total scatter maximization is achieved taking the …


Using Learning Automata For Multi-Objective Generation Dispatch Considering Cost, Voltage Stability And Power Losses, Ari̇f Karakaş, Celal Kocatepe, Fangxing Li Jan 2011

Using Learning Automata For Multi-Objective Generation Dispatch Considering Cost, Voltage Stability And Power Losses, Ari̇f Karakaş, Celal Kocatepe, Fangxing Li

Turkish Journal of Electrical Engineering and Computer Sciences

The economical and secure operation of power systems has significant importance. Due to technical limitations, the best economical operation point is not always the desired operating point for system stability or power losses. In this study, first, the most economical operating point is obtained by solving the non-linear, network-constrained economic dispatch problem using a genetic algorithm. Then, the system voltage stability is analyzed to compare the different possible operating points using V-Q sensitivity analysis. The power losses, obtained for various operating points, are considered the third objective function. Finally, these 3 aspects of cost, voltage stability, and power losses are …


Design And Development Of Workstation For Microparts Manipulation And Assembly, Emrah Deni̇z Kunt, Ahmet Teoman Naskali̇, İslam Shoukry Mohammed Khalil, Asif Sabanovic, Ebubeki̇r Yüksel Jan 2011

Design And Development Of Workstation For Microparts Manipulation And Assembly, Emrah Deni̇z Kunt, Ahmet Teoman Naskali̇, İslam Shoukry Mohammed Khalil, Asif Sabanovic, Ebubeki̇r Yüksel

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, microassembly system design issues are discussed with requirements, constraints and necessities for the development of an assembly platform, and these issues are shown over a versatile and reconfigurable microassembly workstation which is designed and realized as a research tool for investigation of the problems in microassembly and micromanipulation tasks. First prototype of a workstation and the development of a second prototype with enhancements on mechanical and control structure of the system are presented with details on the configuration of the systems. In addition, several experiments using a workstation are presented both on the first and the second …