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- Adaptive characteristic (1)
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- Alternating-direction-implicit finite-difference time-domain (ADI-FDTD) method (1)
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- Antenna design (1)
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Articles 1 - 24 of 24
Full-Text Articles in Physical Sciences and Mathematics
Power Distortion Issues In Wind Turbine Power Systems Under Transient States, Tadeusz Lobos, Jacek Rezmer, Tomasz Sikorski, Zbigniew Waclawek
Power Distortion Issues In Wind Turbine Power Systems Under Transient States, Tadeusz Lobos, Jacek Rezmer, Tomasz Sikorski, Zbigniew Waclawek
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper time-frequency methods have been investigated for complex investigations of transient states in wind power plants. Application of parallel processing in time and frequency domain brought new findings in description of wind power plants working under transient conditions. Proposed algorithms represents standard Short-Time Fourier Transform (STFT) as well as alternative methods associated with Cohen's class: Choi-Williams Distribution (CWD) and Zhao-Atlas-Marks Distribution (ZAMD). In order to explore advantages and disadvantages of the method several experiments were performed using model of squirrel-cage induction machine connected directly to the grid. Investigated phenomena concerned power distortion caused by switching-on capacitor banks and …
Dual-Band Split-Ring Antenna Design For Wlan Applications, S. Cumhur Başaran, Yunus E. Erdemli̇
Dual-Band Split-Ring Antenna Design For Wlan Applications, S. Cumhur Başaran, Yunus E. Erdemli̇
Turkish Journal of Electrical Engineering and Computer Sciences
A dual-band microstrip antenna based on split-ring elements is introduced for WLAN (2.4/5.2 GHz) applications. The proposed split-ring antenna (SRA) has a compact novel design which provides about 2% impedance-bandwidth without a need for additional matching network. Analysis and design of the proposed microstrip antenna is carried out by means of full-wave simulators based on the finite-element method.
Dispersion Analysis Of The Adi-Fdtd And S-Fdtd Methods, Mehmet Kuşaf, Abdullah Y. Öztoprak
Dispersion Analysis Of The Adi-Fdtd And S-Fdtd Methods, Mehmet Kuşaf, Abdullah Y. Öztoprak
Turkish Journal of Electrical Engineering and Computer Sciences
Numerical dispersion performances of ADI-FDTD and S-FDTD methods have been compared. It has been shown that for time steps below the stability limits of the S-FDTD method it has much better dispersion performance compared with the ADI-FDTD method and that the S-FDTD method can be usefully employed for space increments in the order of \lambda/25 to \lambda/50.
My Collaboration With Raj Mittra: Contributions To The Theory Of Perfectly Matched Layers, Mustafa Kuzuoğlu
My Collaboration With Raj Mittra: Contributions To The Theory Of Perfectly Matched Layers, Mustafa Kuzuoğlu
Turkish Journal of Electrical Engineering and Computer Sciences
No abstract provided.
A Summary Of Recent Developments On Metamaterial-Based And Metamaterial-Inspired Efficient Electrically Small Antennas, Aycan Erentok, Richard W. Ziolkowski
A Summary Of Recent Developments On Metamaterial-Based And Metamaterial-Inspired Efficient Electrically Small Antennas, Aycan Erentok, Richard W. Ziolkowski
Turkish Journal of Electrical Engineering and Computer Sciences
This paper summarizes our recent research efforts to realize efficient electrically small antenna (EESA) systems based on ideal analytical and numerical metamaterial-based antenna systems, and physically realized metamaterial-inspired antenna designs. Our theoretical and numerical studies of the radiation and resonance behaviors of the proposed metamaterial-based EESA systems, as well as our efforts to conceptualize structures which might be used to build them, have led to the discovery of several realizable metamaterial-inspired EESA systems. The measurement results confirm the numerical performance predictions.
Use Of Characteristic Basis Function Method For Scattering From Terrain Profiles, Atacan Yağbasan, Celal Alp Tunç, Vakur B. Ertürk, Ayhan Altintas, Raj Mittra
Use Of Characteristic Basis Function Method For Scattering From Terrain Profiles, Atacan Yağbasan, Celal Alp Tunç, Vakur B. Ertürk, Ayhan Altintas, Raj Mittra
Turkish Journal of Electrical Engineering and Computer Sciences
An integral equation (IE) based solution procedure is presented for the rigorous analysis of scattering from terrain profiles. The procedure uses characteristic basis function method (CBFM), which is hybridized with the forward-backward method (FBM), to reduce the storage requirements of the resultant Method of Moments (MoM) impedance matrix, as well as to accelerate the solution procedure. Numerical results in the form of induced current and scattered field are presented to assess the accuracy and efficiency of the solution procedure.
Recent Advances In Perfectly Matched Layers In Finite Element Applications, Özlem Özgün, Mustafa Kuzuoğlu
Recent Advances In Perfectly Matched Layers In Finite Element Applications, Özlem Özgün, Mustafa Kuzuoğlu
Turkish Journal of Electrical Engineering and Computer Sciences
We present a comparative evaluation of two novel and practical perfectly matched layer (PML) implementations to the problem of mesh truncation in the finite element method (FEM): locally-conformal PML, and multi-center PML techniques. The most distinguished feature of these methods is the simplicity and flexibility to design conformal PMLs over challenging geometries, especially those with curvature discontinuities, in a straightforward way without using artificial absorbers. These methods are based on specially- and locally-defined complex coordinate transformations inside the PML region. They can easily be implemented in a conventional FEM by just replacing the nodal coordinates inside the PML region by …
Analysis And Optimization Of Mobile Phone Antenna Radiation Performance In The Presence Of Head And Hand Phantoms, Erdem Ofli, Chung-Huan Li, Nicolas Chavannes, Niels Kuster
Analysis And Optimization Of Mobile Phone Antenna Radiation Performance In The Presence Of Head And Hand Phantoms, Erdem Ofli, Chung-Huan Li, Nicolas Chavannes, Niels Kuster
Turkish Journal of Electrical Engineering and Computer Sciences
A commercial clam shell phone CAD model is used to numerically investigate the effect of a hand phantom on mobile phone antenna radiation performance. The simulation results show that the grip of the hand phantom is the most important parameter to antenna performance. The antenna is converted into a parameterized form, then optimized to achieve the targeted multi-band performance in real-usage conditions.
Comparison Of Rectangular And Cylindrical Fdtd Representations On A Ring Resonator Problem, Funda Akleman, Levent Sevgi̇
Comparison Of Rectangular And Cylindrical Fdtd Representations On A Ring Resonator Problem, Funda Akleman, Levent Sevgi̇
Turkish Journal of Electrical Engineering and Computer Sciences
The aim of this paper is to discuss rectangular and cylindrical representations of finite-difference time-domain (FDTD) method over characteristic tests and comparisons. A ring resonator is chosen as a canonical structure and modeled with both rectangular- and cylindrical-FDTD packages. Calibration against analytical exact solution derived in terms of cylindrical Bessel functions is also performed. It is shown that rectangular-FDTD with periodic boundary condition, where the computation domain is reduced, can also be applied in modeling circular structures.
Method Of Moments Solution By Using Sinc-Type Basis Functions For The Scattering From A Finite Number Of Conducting Strip Gratings, Taner Oğuzer, Fadil Kuyucuoğlu
Method Of Moments Solution By Using Sinc-Type Basis Functions For The Scattering From A Finite Number Of Conducting Strip Gratings, Taner Oğuzer, Fadil Kuyucuoğlu
Turkish Journal of Electrical Engineering and Computer Sciences
A numerical method of moments (MoM) solution is applied to the electromagnetic scattering from a periodic finite conducting strip array when the incident electromagnetic plane wave E and H polarizations illuminate the grating. For such grating strip geometry, we deal with singular integral equations arising from Neumann and Dirichlet boundary conditions. MoM is applied using band-limited sinc functions as basis and testing functions. The Galerkin approach is followed in MoM formulation. The properties of the sinc function, with the infinite integral, are exploited in the computations of the main matrix elements. Also, the error in our approach goes to zero …
Zero Crossing Counter For Accuracy Improvement Of Fmcw Range Detection, Si̇nan Kurt, Şi̇mşek Demi̇r, Altunkan Hizal
Zero Crossing Counter For Accuracy Improvement Of Fmcw Range Detection, Si̇nan Kurt, Şi̇mşek Demi̇r, Altunkan Hizal
Turkish Journal of Electrical Engineering and Computer Sciences
For civil and military purposes FMCW radars are widely used. The theoretical background is well-established. Nevertheless, improvement of various aspects of these radars is still required. Signal processing is one of the crucial points of the system which determines the capabilities of the radar. In this study a zero crossing detector implementation, which can be efficiently used for target detection and range calculation in short range FMCW range detector is proposed. The duration between consecutive zero-crossings are used as the data instead of the number of cycles per unit time. Experimental evaluation of its performance is also given.
A Novel Theoretical Procedure To Determine Absorption And Gain Coefficients In A Symmetric Single Step-Index Quantum Well Laser, Mustafa Temi̇z, Özgür Önder Karakilinç, Mehmet Ünal
A Novel Theoretical Procedure To Determine Absorption And Gain Coefficients In A Symmetric Single Step-Index Quantum Well Laser, Mustafa Temi̇z, Özgür Önder Karakilinç, Mehmet Ünal
Turkish Journal of Electrical Engineering and Computer Sciences
If the indices n_{II}, n_{I,III} of the regions, the thickness 2a of the active region (AR) and the wavelength \lambda for a single symmetric step-index quantum well laser (SSSIQWL) are given, the normalized propagation constant (NPC) \alpha is obtained. In this novel method, absorption and gain coefficients for the SSSIQWL have been obtained in terms of the NPCs \alpha in the even and odd fields, directly.
Role Of Artificial Intelligence In The Reliability Evaluation Of Electric Power Systems, Chanan Singh, Lingfeng Wang
Role Of Artificial Intelligence In The Reliability Evaluation Of Electric Power Systems, Chanan Singh, Lingfeng Wang
Turkish Journal of Electrical Engineering and Computer Sciences
Every reliability analysis effort, in some way, involves searching the state space of the system for those states that represent the events of interest, typically failure of the system or a given node to meet the demand. This essentially translates into a search procedure to efficiently identify states to be examined and then using a mechanism to evaluate these states. Traditionally, reliability analysis methods are based either on an implicit or explicit enumeration process or Monte Carlo sampling. More recently, methods based on artificial intelligence have been investigated both as an alternative to Monte Carlo for the search process as …
Distance Relaying Algorithm For Double-Circuit Transmission Line With Compensation For Reactance Effect Under Standard Availability Of Measurements, Jan Izykowski, Marcin Bozek
Distance Relaying Algorithm For Double-Circuit Transmission Line With Compensation For Reactance Effect Under Standard Availability Of Measurements, Jan Izykowski, Marcin Bozek
Turkish Journal of Electrical Engineering and Computer Sciences
This paper deals with non-pilot distance protection of a double-circuit transmission line. Negative impact of the reactance effect, appearing in measuring a fault loop impedance, on operation of the relay is discussed. An adaptive algorithm allowing one to prevent the relay from mis- or mal-operation caused by the reactance effect is introduced. The algorithm is designed for a standard availability of measurements from one end of the double-circuit line, i.e. when three-phase voltage and current from the faulted line circuit, and additionally zero-sequence current from the healthy line circuit, are provided as the relay input signals. The algorithm is based …
From Engineering Electromagnetics To Electromagnetic Engineering: Using Computational Electromagnetics For Synthesis Problems, Anton G. Tijhuis, Martijn C. Van Beurden, Bastiaan P. De Hon, Hubregt J. Visser
From Engineering Electromagnetics To Electromagnetic Engineering: Using Computational Electromagnetics For Synthesis Problems, Anton G. Tijhuis, Martijn C. Van Beurden, Bastiaan P. De Hon, Hubregt J. Visser
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, a two-stage approach is proposed for using computational electromagnetics in antenna engineering. First, stochastic optimization techniques are used in combination with approximate models. Second, line-search techniques are combined with full-wave modeling. For the first stage, we show an illustrative example. The second stage is considered in detail; both the acceleration of the underlying field computations and the implementation of the optimization are discussed.
The Characteristic Basis Function Method (Cbfm): A Numerically Efficient Strategy For Solving Large Electromagnetic Scattering Problems, Eugenio Lucente, Gianluigi Tiberi, Agostino Monorchio, Giuliano Manara, Raj Mittra
The Characteristic Basis Function Method (Cbfm): A Numerically Efficient Strategy For Solving Large Electromagnetic Scattering Problems, Eugenio Lucente, Gianluigi Tiberi, Agostino Monorchio, Giuliano Manara, Raj Mittra
Turkish Journal of Electrical Engineering and Computer Sciences
The objective of this paper is to describe a numerically efficient strategy for solving large electromagnetic scattering problems. This novel approach, termed as the Characteristic Basis Function Method (CBFM), is based on utilizing Characteristic Basic Functions (CBFs)-special functions defined on macro domains (blocks)-that include a relatively large number of conventional sub-domains discretized by using triangular or rectangular patches. The CBFs can be derived either analytically (from PO solutions), or by applying the conventional MoM. Use of these basis functions leads to a significant reduction in the number of unknowns, and results in a substantial size reduction of the MoM matrix. …
Generation Of High-Repetition-Rate Pulses Utilizing Cascaded Single Mode Fiber And Semiconductor Optical Amplifier, Jianwei Wu, Hai-Bo Bao
Generation Of High-Repetition-Rate Pulses Utilizing Cascaded Single Mode Fiber And Semiconductor Optical Amplifier, Jianwei Wu, Hai-Bo Bao
Turkish Journal of Electrical Engineering and Computer Sciences
To generate high-repetition-rate optical pulses, a novel and simple device is demonstrated, in which the cascaded single mode fiber (SMF) with negative third order dispersion and semiconductor optical amplifier (SOA) are adopted. Numerical research results show that let an optical pulse with center wavelength in zero dispersion wavelength of optical fiber transit in SMF for generating an oscillation pulse. Subsequently, the followed SOA is provided for amplification. As a consequence, the high-repetition-rate optical pulses can be obtained.
Online Tuning Of Set-Point Regulator With A Blending Mechanism Using Pi Controller, Engi̇n Yeşi̇l, Müjde Güzelkaya, İbrahi̇m Eksi̇n, Ö. Aydin Teki̇n
Online Tuning Of Set-Point Regulator With A Blending Mechanism Using Pi Controller, Engi̇n Yeşi̇l, Müjde Güzelkaya, İbrahi̇m Eksi̇n, Ö. Aydin Teki̇n
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, a new control structure that exploits the advantages of one degree of freedom (1-DOF) and two degree of freedom (2-DOF) control structures with an online tuned set-point regulator with blending mechanism (SPR-BM) is proposed. In this structure, the filtered output of the reference and the pure reference signals are blended so that the overall performance of the system is ameliorated with respect to load disturbance rejection and set-point following. Internal Model Control (IMC) based PI controller is used as the primary controller and the blending dynamics are determined with the aim of producing a system output that …
A New Approach Using Temporal Radial Basis Function In Chronological Series, Mustapha Guezouri
A New Approach Using Temporal Radial Basis Function In Chronological Series, Mustapha Guezouri
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, we present an extended form of Radial Basis Function network called Temporal-RBF (T-RBF) network. This extended network can be used in decision rules and classification in Spatio-Temporal domain applications, like speech recognition, economic fluctuations, seismic measurements and robotics applications. We found that such a network complies with relative ease to constraints such as capacity of universal approximation, sensibility of node, local generalisation in receptive field, etc. For an optimal solution based on a probabilistic approach with a minimum of complexity, we propose two TRBF models (1 and 2). Application to the problem of Mackey-Glass time series has …
Biomedical Circuits And Systems Dedicated For Sensing And Neurostimulation: Case Study On Urinary Bladder Dysfunctions, Mohamad Sawan, Aguibou Ba, Faycal Mounaim, Jacques Corcos, Mostafa Elhilali
Biomedical Circuits And Systems Dedicated For Sensing And Neurostimulation: Case Study On Urinary Bladder Dysfunctions, Mohamad Sawan, Aguibou Ba, Faycal Mounaim, Jacques Corcos, Mostafa Elhilali
Turkish Journal of Electrical Engineering and Computer Sciences
This paper covers circuits and systems techniques for the construction of high reliability biosensing and neurostimulation smart medical devices. Such microsystems are dedicated for interconnections through the peripheral neural systems. Case study related to applications such as bladder control is discussed. Available electrical neurostimulation techniques for the rehabilitation of urinary bladder functions do not allow an adequate voiding due to dyssynergia between the bladder and the sphincter. A new implantable stimulator, built with commercially available electronic components, was designed to overcome these difficulties. The proposed system performs two types of stimulations: Selective Stimulation for bladder voiding and Permanent Stimulation to …
A Study On The Reliability Of Polyester Insulators Blended With Borax, Aysel Ersoy, Yasi̇n Özcelep, Ayten Kuntman
A Study On The Reliability Of Polyester Insulators Blended With Borax, Aysel Ersoy, Yasi̇n Özcelep, Ayten Kuntman
Turkish Journal of Electrical Engineering and Computer Sciences
Tracking is the main factor which limits the safe working electric stress of insulation in power system applications. Polymer samples have been tested in laboratory conditions according to ASTM D2303 on accelerated inclined plane tracking test. In this paper, a model based on improved Weibull statistics is proposed for estimating the breakdown time of polymeric insulating materials with borax. The confidence intervals of the Weibull shape parameter and the Weibull scale parameter are determined for the borax concentration values using the Weibull 7++ program.
Pattern Synthesis With Uniform Circular Arrays For The Reduction Of Wcdma Intercell Interference, Mohammed Al-Husseini, Elias Yaacoub, Karim Y. Kabalan, Ali El-Hajj
Pattern Synthesis With Uniform Circular Arrays For The Reduction Of Wcdma Intercell Interference, Mohammed Al-Husseini, Elias Yaacoub, Karim Y. Kabalan, Ali El-Hajj
Turkish Journal of Electrical Engineering and Computer Sciences
The deployment of advanced antenna arrays at the base stations of cellular systems is a key technique in reducing intercell interference, and thus increasing the number of served users. Uniform circular arrays (UCAs) provide 360 degrees of coverage, their patterns are steering-invariant and their sidelobe levels are controllable. This paper investigates the use of UCAs having specially synthesized patterns at the base stations of WCDMA cellular systems. The decrease in the ratio of intercell interference to intracell power resulting from the use of these arrays in a beam-steering scheme will be assessed, and the advantages and disadvantages of each pattern …
Evolutionary Algorithms For The Unit Commitment Problem, A. Şi̇ma Uyar, Belgi̇n Türkay
Evolutionary Algorithms For The Unit Commitment Problem, A. Şi̇ma Uyar, Belgi̇n Türkay
Turkish Journal of Electrical Engineering and Computer Sciences
This paper compares three evolutionary computation techniques, namely Steady-State Genetic Algorithms, Evolutionary Strategies and Differential Evolution for the Unit Commitment Problem. The comparison is based on a set of experiments conducted on benchmark datasets as well as on real-world data obtained from the Turkish Interconnected Power System. The results of two state-of-the-art evolutionary approaches, namely a Generational Genetic Algorithm and a Memetic Algorithm for the same benchmark datasets are also included in the paper for comparison. The tests show that Differential Evolution is the best performer among all approaches on the test data used in the paper. The performances of …
Comparison Of Basic Linear Filters In Extracting Auditory Evoked Potentials, Serap Aydin
Comparison Of Basic Linear Filters In Extracting Auditory Evoked Potentials, Serap Aydin
Turkish Journal of Electrical Engineering and Computer Sciences
In the present study, the performances of two well-known linear filtering techniques are compared for extraction of auditory Evoked Potential (EP) from a relatively small number of sweeps. Both experimental and simulated data are filtered by the two algorithms into two groups. Group A consists of Wiener filtering (WF) applications, where conventional WF and Coherence Weighted WF (CWWF)) have been assessed in combination with the Subspace Method (SM). Group B consists of the well-known adaptive filtering algorithms Least Mean Square (LMS), Recursive Least Square (RLS), and one-step Kalman filtering (KF). Both groups are tested with respect to signal-to-noise ratio (SNR) …