A Novel And Efficient Algorithm For Adaptive Filtering: Artificial Bee Colony Algorithm,
2011
TÜBİTAK
A Novel And Efficient Algorithm For Adaptive Filtering: Artificial Bee Colony Algorithm, Nurhan Karaboğa, Mehmet Bahadir Çeti̇nkaya
Turkish Journal of Electrical Engineering and Computer Sciences
The uni-modal error surfaces and intrinsic stable behaviors of adaptive finite impulse response (FIR) filters make gradient based algorithms very effective in the design of these filters. Gradient based design methods are well developed for the design of adaptive FIR filters and widely applied to the distinct areas such as noise cancellation, system identification and channel equalization. However, the studies on adaptive infinite impulse response (IIR) filters are not as common as adaptive FIR filters since the stability during the adaptation process may not be ensured in some applications, and the convergence to the optimal design is not always guaranteed …
A New Lvi Assisted Psfb Dc-Dc Converter,
2011
TÜBİTAK
A New Lvi Assisted Psfb Dc-Dc Converter, Ahmet Faruk Bakan
Turkish Journal of Electrical Engineering and Computer Sciences
In this study, a new Phase Shifted Full Bridge (PSFB) Pulse Width Modulated (PWM) isolated dc-dc converter is proposed. In the proposed converter, resonant inductor is replaced with Linear Variable Inductor (LVI) that is controlled by output current. The soft switching operation range is increased and the dependency of ZVS operation on the load current is decreased. The required energy for ZVS operation at low current levels is obtained by means of the high value of the LVI. The value of LVI decreases approximately linearly with increasing current. At high current levels parasitic resonance and duty cycle loss are decreased. …
Determining Wave Propagation Characteristics Of Mv Xlpe Power Cable Using Time Domain Reflectometry Technique,
2011
TÜBİTAK
Determining Wave Propagation Characteristics Of Mv Xlpe Power Cable Using Time Domain Reflectometry Technique, Ghulam Murtaza Hashmi, Ruslan Papazyan, Matti Lehtonen
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, the wave propagation characteristics of single-phase medium voltage (MV) cross-linked polyethylene (XLPE) power cable are determined using time domain reflectometry (TDR) measurement technique. TDR delivers the complex propagation constant (attenuation and phase constant) of lossy cable transmission line as a function of frequency. The frequency-dependent propagation velocity is also determined from the TDR measurements through the parameters extraction procedure. The calibration of the measuring system (MS) is carried-out to avoid the effect of multiple reflections on the accuracy of measurements. The results obtained from the measurements can be used to localize the discontinuities as well as the …
Cognitive And Encrypted Communications: State Of The Art And A New Approach For Frequency-Agile Filters,
2011
TÜBİTAK
Cognitive And Encrypted Communications: State Of The Art And A New Approach For Frequency-Agile Filters, Yahya Lakys, Balwant Godara, Alain Fabre
Turkish Journal of Electrical Engineering and Computer Sciences
Several communication techniques are investigated in the first part of this paper: software radio, cognitive radio and encrypted communications. State of the art of research on agile and reconfigurable filters, passive as well as active, necessary for transceivers is then made and various tables for comparison are given. In the third part, a new theory for a 2^{nd}-order frequency-agile filter is introduced. The center frequency of the filter is proportional to the gain of a feedback amplifier and thus can be tuned over a wide frequency range. This new theory is thereafter generalized to the n^{th}-class leading to a center …
Asynchronous Signal Processing For Brain-Computer Interfaces,
2011
TÜBİTAK
Asynchronous Signal Processing For Brain-Computer Interfaces, Seda Senay, Luis F. Chaparro, Mingui Sun, Robert Sclabassi, Aydin Akan
Turkish Journal of Electrical Engineering and Computer Sciences
Brain-computer interfaces (BCIs) provide a way to monitor and treat neurological diseases. An important application of BCIs is the monitoring and treatment of epilepsy, a neurological disorder characterized by recurrent unprovoked seizures, symptomatic of abnormal, excessive or synchronous neuronal activity in the brain. BCIs contain an array of sensors that gather and transmit data under the constrains of low-power and minimal data transmission. Asynchronous sigma delta modulators (ASDMs) are considered an alternative to synchronous analog to digital conversion. ASDMs are non-linear feedback systems that enable time-encoding of analog signals, from which the signal can be reconstructed. An efficient reconstruction of …
An Extended Component-Based Reliability Model For Protective Systems To Determine Routine Test Schedule,
2011
TÜBİTAK
An Extended Component-Based Reliability Model For Protective Systems To Determine Routine Test Schedule, Amir Abbarin, Mahmoud Fotuhi Firuzabad, Aydoğan Özdemi̇r
Turkish Journal of Electrical Engineering and Computer Sciences
This paper presents a novel approach for evaluating the reliability of protective systems taking into account its components reliability. In this paper, a previously proposed extended model is used for a directional over-current scheme. In the extended model, the impacts of individual protective components are taken into account. An optimum routine test schedule is determined for each protective component as a separate unit. A comparison is made to show that the proposed approach has excellence over conventional routine test inspections. Impacts of factors such as circuit breaker inadvertent opening, required time for performing routine test inspections, human mistakes and self-checking …
A Complete Motor Protection Algorithm Based On Pca And Ann: A Real Time Study,
2011
TÜBİTAK
A Complete Motor Protection Algorithm Based On Pca And Ann: A Real Time Study, Okan Özgönenel, Turgay Yalçin
Turkish Journal of Electrical Engineering and Computer Sciences
Protection of an induction motor (IM) against possible faults, such as a stator winding fault, due to thermal deterioration, rotor bar and bearing failures, is very important in environments in which it is used intensively, as in industry as an actuator. In this work, a real time digital protection algorithm based on principal component analysis (PCA) and neural network method is presented for induction motors. The proposed protection algorithm covers internal winding faults (also known as stator faults), broken rotor bar faults, and bearing faults. Many laboratory experiments have been performed on a specially designed induction motor to evaluate the …
Remote Mutual Authentication And Key Agreement Scheme Based On Elliptic Curve Cryptosystem,
2011
TÜBİTAK
Remote Mutual Authentication And Key Agreement Scheme Based On Elliptic Curve Cryptosystem, Eunjun Yoon
Turkish Journal of Electrical Engineering and Computer Sciences
Remote mutual authentication is an important part of security, along with confidentiality and integrity, for systems that allow remote access over untrustworthy networks, like the Internet. In 2006, Shieh-Wang pointed out the weakness of Juang's remote mutual authentication scheme using smart card and further proposed a novel remote user authentication scheme using smart card. However, this paper demonstrates that Shieh-Wang's scheme still does not provide perfect forward secrecy and is vulnerable to a privileged insider's attack. We also present an improved scheme based on the Elliptic Curve Diffie-Hellman problem (ECDHP) and secure one-way hash function, in order to isolate such …
Fully Integrated Universal Biquads Using Operational Transresistance Amplifiers With Mos-C Realization,
2011
TÜBİTAK
Fully Integrated Universal Biquads Using Operational Transresistance Amplifiers With Mos-C Realization, Ahmet Gökçen, Selçuk Kilinç, Uğur Çam
Turkish Journal of Electrical Engineering and Computer Sciences
Universal biquadratic filters employing operational transresistance amplifiers are presented. All 5 different second-order filtering functions, namely low-pass, high-pass, band-pass, notch, and all-pass, can be realized. The quality factor of the filters can be adjusted electronically without affecting resonant frequency. The configuration can be made fully integrated based on MOS-C realization, by making use of the current differencing and internally grounded inputs of OTRA. PSpice simulation results are given to verify the theoretical analysis.
Online Speed Control Of A Brushless Ac Servomotor Based On Artificial Neural Networks,
2011
TÜBİTAK
Online Speed Control Of A Brushless Ac Servomotor Based On Artificial Neural Networks, Si̇bel Partal, İbrahi̇m Şenol, Ahmet Faruk Bakan, Kamuran Nur Beki̇roğlu
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, an alternative approach to speed estimation of brushless AC servomotors is presented. Speed control is realized in the following steps. First, the servomotor was mathematically modelled; the driver system was designed and speed control of the servomotor was accomplished with feedback. Next, a network structure representing the electrical and mechanical properties of the servomotor was built via Artificial Neural Network (ANN) and trained with the results of the first step. The weights obtained from the neural nwork training were inserted into the control algorithm in accordance with the ANN. Finally, speed estimation was achieved based on the …
Electromagnetic Scattering From Layered Strip Geometries: The Method Of Moments Study With The Sinc Basis,
2011
TÜBİTAK
Electromagnetic Scattering From Layered Strip Geometries: The Method Of Moments Study With The Sinc Basis, Taner Oğuzer, Fadil Kuyucuoğlu, İbrahi̇m Avgin
Turkish Journal of Electrical Engineering and Computer Sciences
Electromagnetic scattering from strips of layers is analyzed using the method of moments (MoM) for both polarizations in spatial domain with the sinc-type orthogonal sets as basis and testing functions. We exploited the sinc function's properties of exponential convergence, the orthogonality, easy convolution and better handling of singular kernels in MoM procedure resulting in fast performance and reasonable accuracy even in ordinary MoM treatment. We transferred the integral of the Hankel function multiplied by sinc functions to Hankel function introducing a slight error with large band width. We proved that this relative error during the generation of the main matrix …
An Effective Real Coded Ga Based Fuzzy Controller For Speed Control Of A Bldc Motor Without Speed Sensor,
2011
TÜBİTAK
An Effective Real Coded Ga Based Fuzzy Controller For Speed Control Of A Bldc Motor Without Speed Sensor, Ömer Aydoğdu, Ramazan Akkaya
Turkish Journal of Electrical Engineering and Computer Sciences
In this study, an effective Real Coded Genetic Algorithm (GA) based optimal fuzzy controller is proposed. The fuzzy controller is used for sensorless speed control of a Brushless DC (BLDC) motor in DSP based application system. The advantages of adopting a real coded GA for the design and optimization of fuzzy controllers, which have a great deal of design and optimization parameters, are analyzed. Having accomplished optimization of developed fuzzy control system, a multi-objective performance index has been defined and it has been used as an objective function to be minimized in the real coded GA. Thus, the system can …
Low-Complexity Parameters Estimator For Multiple 2d Domain Incoherently Distributed Sources,
2011
TÜBİTAK
Low-Complexity Parameters Estimator For Multiple 2d Domain Incoherently Distributed Sources, Xiansheng Guo, Qun Wan, Xiaofeng Shen, Heng Dou
Turkish Journal of Electrical Engineering and Computer Sciences
A new low-complexity parameters estimator for multiple two-dimensional (2D) domain incoherently distributed (ID) sources is presented. One 2D domain ID source is parameterized with four parameters, the central azimuth direction-of-arrival (DOA), azimuth angular spread, central elevation DOA and elevation angular spread. Based on the eigenstructure between the steering matrix and signal subspace, an average total least-squares via rotational invariance technique (TLS-ESPRIT) is used to estimate the central elevation DOA, and then a generalized multiple signal classification (GMUSIC) algorithm is derived to estimate the central azimuth DOA. Utilizing preliminary estimates obtained at a pre-processing stage, the angular spread parameters can be …
Rate 1 Space-Time And Space-Frequency Spreading Diversity Technique,
2011
TÜBİTAK
Rate 1 Space-Time And Space-Frequency Spreading Diversity Technique, Gökçe Hacioğlu, Ali̇ Gangal
Turkish Journal of Electrical Engineering and Computer Sciences
In this study, a rate 1 transmitter diversity technique is proposed. The proposed technique uses spreading transform and space-time block coding (STBC) together. Space-time, space-frequency, and frequency diversity applications of the proposed technique are shown. The code matrix of the proposed technique can be designed systematically. The proposed technique needs the channel coefficients to stay constant over transmission of 2 rows of the coding matrix regardless of the size of the coding matrix or the diversity order. However, joint detection of the symbols is required for the proposed technique. We used computer simulations to compare our technique with the quasi-orthogonal …
On The Existence Of Common Lyapunov Functions For Consensus Algorithms Based On Averaging,
2011
TÜBİTAK
On The Existence Of Common Lyapunov Functions For Consensus Algorithms Based On Averaging, Mehmet Akar, Robert Shorten
Turkish Journal of Electrical Engineering and Computer Sciences
This paper addresses distributed deterministic consensus algorithms based on averaging. We relate the conditions for achieving consensus to the existence of a common norm for a set of row-stochastic matrices associated with the original set of averaging matrices. For a system to achieve consensus, it is shown that this associated set of matrices should have a Common Lyapunov Function, even if the original set might not have one.
Ecg Denoising On Bivariate Shrinkage Function Exploiting Interscale Dependency Of Wavelet Coefficients,
2011
TÜBİTAK
Ecg Denoising On Bivariate Shrinkage Function Exploiting Interscale Dependency Of Wavelet Coefficients, Sema Kayhan, Ergun Erçelebi̇
Turkish Journal of Electrical Engineering and Computer Sciences
This paper presents a new method for electrocardiogram (ECG) denoising based on bivariate shrinkage functions exploiting the interscale dependency of wavelet coefficients. Most nonlinear thresholding methods based on wavelet transform denoising assume that the wavelet coefficients are independent. However, wavelet coefficients of ECG signals have significant dependencies. In this paper, we proposed a new method by considering the dependencies between the coefficients and their parents in detail on a bivariate shrinkage function for denoising of an ECG signal corrupted by different types of noises, such as muscle artifact noise, electrode motion, and white noise. In real-time applications, reduction of computational …
Decentralized Robust Load-Frequency Control Of Power System Based On Quantitative Feedback Theory,
2011
TÜBİTAK
Decentralized Robust Load-Frequency Control Of Power System Based On Quantitative Feedback Theory, Aidin Sakhavati, Gevork Gharehpetian, Seyed Hossein Hosseini
Turkish Journal of Electrical Engineering and Computer Sciences
This paper aims at investigating the problem of Load Frequency Control (LFC) in interconnected power systems in order to obtain robustness against uncertainties. A design method for a robust controller, based on Quantitative Feedback Theory (QFT), has been presented in this paper. For a two-area power system, the simulation results show that the system response with the proposed QFT controller exhibits transient response beyond PI controllers. It is also shown that the transient response of the tie line power can also be improved.
Sliding Mode Controller Gain Adaptation And Chattering Reduction Techniques For Dsp-Based Pm Dc Motor Drives,
2011
TÜBİTAK
Sliding Mode Controller Gain Adaptation And Chattering Reduction Techniques For Dsp-Based Pm Dc Motor Drives, Mehmet Dal, Remus Teodorescu
Turkish Journal of Electrical Engineering and Computer Sciences
In order to achieve and maintain the prospective benefits of sliding mode control (SMC) methodology, the phenomenon known as ``chattering'', the main obstacle encountered in real-time applications, has to be suppressed. In this study, two promising switching control gain adaptation and chattering reduction techniques are investigated, and the effectiveness of chattering suppression for current regulation of PM DC drives is tested. The sampling rate was also examined to determine how it affects the amplitude of chattering. This paper concentrates on various combinations of observer-based methods in order to find the best solution for chattering reduction. To find a practical solution …
Minimization Of Load Shedding By Sequential Use Of Linear Programming And Particle Swarm Optimization,
2011
TÜBİTAK
Minimization Of Load Shedding By Sequential Use Of Linear Programming And Particle Swarm Optimization, Mehrdad Tarafdar Hagh, Sadjad Galvani
Turkish Journal of Electrical Engineering and Computer Sciences
Minimization of load shedding during contingency conditions is solved as an optimization problem. As a new topic, instead of local load shedding, total load shedding of a large power system is considered. Power generation rescheduling is considered to minimize the load shedding, as well. Different importance factors for buses are also considered. The linear programming method (LP) is used to solve this problem in a short period of time without considering some power system constraints. Particle swarm optimization (PSO) is also used to solve the problem by considering all power system constraints, but with a longer solving time. Finally, a …
A Unified Series-Parallel Active Filter System For Nonperiodic Disturbances,
2011
TÜBİTAK
A Unified Series-Parallel Active Filter System For Nonperiodic Disturbances, Mehmet Uçar, Şule Özdemi̇r, Engi̇n Özdemi̇r
Turkish Journal of Electrical Engineering and Computer Sciences
This paper presents a 3-phase, 4-wire unified series-parallel active filter (USPAF) system for periodic and nonperiodic disturbance compensation using a generalized nonactive power theory. The USPAF system consists of a series active filter (AF), parallel AF, and split DC-link capacitors with the midpoint of the DC-link connected to the neutral wire. The generalized nonactive power theory is applicable to single-phase or multiphase, sinusoidal or nonsinusoidal, periodic or nonperiodic, and balanced or unbalanced electrical systems. The theory was implemented previously in a parallel AF. In this study, the USPAF system is proposed to compensate for the nonsinusoidal and nonperiodic currents and …
