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Articles 7501 - 7530 of 10319
Full-Text Articles in Physical Sciences and Mathematics
Securing Fuzzy Vault Schemes Through Biometric Hashing, Cengi̇z Örenci̇k, Thomas Brochmann Pedersen, Erkay Savaş, Mehmet Keski̇nöz
Securing Fuzzy Vault Schemes Through Biometric Hashing, Cengi̇z Örenci̇k, Thomas Brochmann Pedersen, Erkay Savaş, Mehmet Keski̇nöz
Turkish Journal of Electrical Engineering and Computer Sciences
The fuzzy vault scheme is a well-known technique to mitigate privacy, security, and usability related problems in biometric identification applications. The basic idea is to hide biometric data along with secret information amongst randomly selected chaff points during the enrollment process. Only the owner of the biometric data who presents correct biometrics can recover the secret and identify himself. Recent research, however, has shown that the scheme is vulnerable to certain types of attacks. The recently proposed ``correlation attack'', that allows linking two vaults of the same biometric, pose serious privacy risks that have not been sufficiently addressed. The primary …
Washout Filter Based Control For The Hodgkin-Huxley Nerve Cell Dynamics, Reşat Özgür Doruk
Washout Filter Based Control For The Hodgkin-Huxley Nerve Cell Dynamics, Reşat Özgür Doruk
Turkish Journal of Electrical Engineering and Computer Sciences
In this work we present a washout filter based control approach for stabilizing the oscillations in Hodgkin-Huxley type neurons. The oscillations occur due to the bifurcations that arise from the potassium and sodium channel conductance deviations. The MATCONT toolbox software environment was used for analysis of the bifurcation points in conjunction with MATLAB. The simulations of the Hodgkin-Huxley (HH) model at those points are provided to validate the results obtained from the MATCONT software. Then a washout filter is proposed to stabilize the oscillations occur at the Hopf bifurcation points where the external current injection is used to provide the …
A Robust Method For State Estimation Of Power System With Upfc, Mehrdad Tarafdar Hagh, Mehdi Ahmadi Jirdehi
A Robust Method For State Estimation Of Power System With Upfc, Mehrdad Tarafdar Hagh, Mehdi Ahmadi Jirdehi
Turkish Journal of Electrical Engineering and Computer Sciences
This paper presents a Least Absolute Value (LAV) state estimator for power system using a new method called Recursive Least Squares (RLS). Also, a suitable model is used for state estimation of power system that includes a Unified Power Flow Controller (UPFC). The IEEE 14-bus test system is used to show the validity of the proposed algorithm in estimation of power system states as well as the states of controllable parameters of UPFC.
A Small Scale Education Experiment Kit With Wind Generator-Pem Electrolyser System And Modelling, Özcan Atlam
A Small Scale Education Experiment Kit With Wind Generator-Pem Electrolyser System And Modelling, Özcan Atlam
Turkish Journal of Electrical Engineering and Computer Sciences
A small scale experiment wind energy kit is prepared in order to introduce renewable energy applications. The kit consists of a wind turbine with horizontal axis, a direct current (dc) motor as generator and variable wind excitation system. Performance characteristics of the wind system are defined for different wind speeds. It is found that at the highest 10 m/s wind excitation, the maximum turbine mechanical power from wind is about 0.30 W at 5.3 V., maximum output power of the generator is about 0.18 W and maximum electrical efficiency is about 7% at 4.27 V., wind turbine power coefficients C_p …
A Novel Method For Lung Segmentation On Chest Ct Images: Complex-Valued Artificial Neural Network With Complex Wavelet Transform, Murat Ceylan, Yüksel Özbay, Osman Nuri̇ Uçan, Erkan Yildirim
A Novel Method For Lung Segmentation On Chest Ct Images: Complex-Valued Artificial Neural Network With Complex Wavelet Transform, Murat Ceylan, Yüksel Özbay, Osman Nuri̇ Uçan, Erkan Yildirim
Turkish Journal of Electrical Engineering and Computer Sciences
Image segmentation is an important step in many computer vision algorithms. The objective of segmentation is to obtained an optimal region of convergences (ROC). Error in this stage will impact all higher level activities. This paper focuses on a new efficient method denoted as Complex-Valued Artificial Neural Network with Complex Wavelet Transform (CWT-CVANN) for the segmentation of lung region on chest CT images. In this combined architecture is composed of two cascade stages: feature extraction with various levels of complex wavelet transform and segmentation with complex-valued artificial neural network. Here, 32 CT images of 6 female and 26 male patients …
Fault Detection And Identification For Voltage Sag State Estimation In Power Systems, Jamal Beiza, Seyed Hossein Hosseinian, Behrooz Vahidi
Fault Detection And Identification For Voltage Sag State Estimation In Power Systems, Jamal Beiza, Seyed Hossein Hosseinian, Behrooz Vahidi
Turkish Journal of Electrical Engineering and Computer Sciences
This paper presents a novel approach for fault detection and identification in order to estimate voltage sag during a fault. One of the best approaches for voltage sag estimation is instantaneous voltage estimation. The approach uses traditional state estimation where redundant measurements are available. The proposed method is used to estimate voltage sag performance during a fault. At the fault duration, the grid topology is changed. In such a case the measurement matrix must be re-determined at the fault duration. The proposed approach is an efficient method for fault detection and identification which is based on residual analysis and topology …
Robust Feedback Design For Nonlinear Systems: A Survey, Alberto Isidori
Robust Feedback Design For Nonlinear Systems: A Survey, Alberto Isidori
Turkish Journal of Electrical Engineering and Computer Sciences
No abstract provided.
Sdre Optimal Control Of Drug Administration In Cancer Treatment, Mehmet İti̇k, Meti̇n Uymaz Salamci̇, Stephen Paul Banks
Sdre Optimal Control Of Drug Administration In Cancer Treatment, Mehmet İti̇k, Meti̇n Uymaz Salamci̇, Stephen Paul Banks
Turkish Journal of Electrical Engineering and Computer Sciences
In this study, we apply State Dependent Riccati Equation (SDRE) based optimal control technique to a nonlinear tumor growth model. The model consists of three biological cells which are normal tissue, tumor and immune cells. The effect of chemotherapy treatment is also included in the model. Chemotherapy administration is considered as a control input to the nonlinear cancer dynamics and the amount of administered drug is determined by using SDRE optimal control. The optimal control is applied to the model in order not only to drive the tumor cells to the healthy equilibrium state but also to minimize the amount …
Fractional Order Sliding Mode Control With Reaching Law Approach, Mehmet Önder Efe
Fractional Order Sliding Mode Control With Reaching Law Approach, Mehmet Önder Efe
Turkish Journal of Electrical Engineering and Computer Sciences
Fractional order sliding mode control is studied in this paper. The control objectives are achieved by adopting the reaching law approach of sliding mode control. The main contribution of this work is to show that the philosophy of integer order sliding mode control is valid also for the systems represented by fractional order operators. A sufficient condition and its implications for stability are given. Matched and unmatched uncertainties are studied. The attractor nature of the switching manifold is analyzed together with a stable sliding subspace design condition. The claims are justified through a set of simulations and the results obtained …
Asynchronous Particle Swarm Optimization-Based Search With A Multi-Robot System: Simulation And Implementation On A Real Robotic System, Sali̇h Burak Akat, Veysel Gazi̇, Lino Marques
Asynchronous Particle Swarm Optimization-Based Search With A Multi-Robot System: Simulation And Implementation On A Real Robotic System, Sali̇h Burak Akat, Veysel Gazi̇, Lino Marques
Turkish Journal of Electrical Engineering and Computer Sciences
In this article we consider a version of the Particle Swarm Optimization (PSO) algorithm which is appropriate for search tasks of multi-agent systems consisting of small robots with limited sensing capability. The proposed method adopts asynchronous mechanism for information exchange and position (way point) updates of the agents. Moreover, at each (information exchange) step the agents communicate with only a possibly different subset of the other agents leading to a dynamic neighborhood topology. We implement the algorithm using the Player/Stage realistic robot simulator as well as on real KheperaIII robots using experimentally collected realistic data of ethanol gas concentration. Simulation …
A Novel Algorithm For Sensorless Motion Control Of Flexible Structures, Islam Shoukry Mohammed Khalil, Emrah Deni̇z Kunt, Asif Sabanovic
A Novel Algorithm For Sensorless Motion Control Of Flexible Structures, Islam Shoukry Mohammed Khalil, Emrah Deni̇z Kunt, Asif Sabanovic
Turkish Journal of Electrical Engineering and Computer Sciences
This article demonstrates the validity of using an actuator as a single platform for measurements during a motion control assignment of flexible systems kept free from any kind of measurement. System acceleration level dynamics, parameters and interaction forces with the environment are coupled in an incident reaction torque that naturally rises when a flexible system is subjected to an action imposed by an attached actuator to the system. This work attempts to decouple each of the system parameters out of the incident coupled reaction torque at the interface point of the actuator with the flexible system by way of measurements …
Experimental Investigation Of Shaft Transducerless Speed And Position Control Of Ac Induction And Interior Permanent Magnet Motors, Ömer Göksu, Ahmet Masum Hava
Experimental Investigation Of Shaft Transducerless Speed And Position Control Of Ac Induction And Interior Permanent Magnet Motors, Ömer Göksu, Ahmet Masum Hava
Turkish Journal of Electrical Engineering and Computer Sciences
In order to drive AC motors with high efficiency and high motion performance, and to provide accurate speed/position control, motor shaft speed and/or position feedback is required. For this purpose, usually transducers (encoder, tachogenerator, resolver, etc.) are installed on the shaft. However, transducers are not preferred in most of the applications since they increase the cost and decrease the reliability of the drive due to their failure prone structure and connections. In such applications, the speed and/or position information of the motor is obtained by estimation methods without using shaft transducers. In this work, motor types and speed/position estimation methods …
Direct Discrete-Time Control Of Port Controlled Hamiltonian Systems, Yaprak Yalçin, Leyla Gören Sümer
Direct Discrete-Time Control Of Port Controlled Hamiltonian Systems, Yaprak Yalçin, Leyla Gören Sümer
Turkish Journal of Electrical Engineering and Computer Sciences
The direct discrete time control of Port Controlled Hamiltonian Systems (PCHS) in the sense of energy shaping and damping injection is considered. In order to give a direct discrete time design method for PCHS, firstly an appropriate discrete gradient is proposed, which enables the derivation of a discrete time equation corresponding to the discrete time counterpart of Hamiltonian Systems. Using this proposed discrete-time model, the discrete-time counterpart of Passivity Based Control (PBC) technique is developed for n-degrees-of-freedom mechanical systems. The discrete-time control rules which correspond to the energy shaping and damping assignment are obtained directly using the discrete time model …
Design And Evaluation Of A Linear Switched Reluctance Actuator For Positioning Tasks, António Espírito Santo, Rosário Calado, Carlos Cabrita
Design And Evaluation Of A Linear Switched Reluctance Actuator For Positioning Tasks, António Espírito Santo, Rosário Calado, Carlos Cabrita
Turkish Journal of Electrical Engineering and Computer Sciences
This paper presents the development of a new linear switched reluctance actuator and confirms its applicability to perform positioning tasks. After the explanation of the actuator working principle and the presentation of its electromechanical topology, an analysis is accomplished using a finite elements tool. Based on the theoretical results, an experimental prototype that can develop 150 N was constructed. Its behaviour is observed under two different control methods implemented with microcontrollers. Initially, position is controlled applying a single pulse-driving scheme. Meanwhile, significant improvements are obtained with the introduction of a sliding-mode controller, allowing movements with 1 mm of resolution.
Electric Multipole Moments Of Some Diatomic Molecules Molecules, M. Özgür Sezer, Ayhan Özmen, Hüseyi̇n Yüksel
Electric Multipole Moments Of Some Diatomic Molecules Molecules, M. Özgür Sezer, Ayhan Özmen, Hüseyi̇n Yüksel
Turkish Journal of Physics
Molecular Electric Multipole Moment (MEMM) integrals have been derived for diatomic molecular systems, and then some lower multipole moments as dipole moments and quadrupole moments have been calculated for some diatomic molecules. The calculations have been performed by using our analytical formula over Slater-Type orbitals (STOs) with Cade and Huo's basis sets and the GAMESS program package working with Gaussian-Type basis sets (GTOs). The expressions which involve factorials are given in terms of binomial coefficients in order to speed up calculations. The results have been obtained in agreement with data found in the literature.
Kantowski-Sachs Viscous Fluid Cosmological Model With A Varying \Lambda, Sharad Kandalkar, Pramod Khade, Sunita Gawande
Kantowski-Sachs Viscous Fluid Cosmological Model With A Varying \Lambda, Sharad Kandalkar, Pramod Khade, Sunita Gawande
Turkish Journal of Physics
We study the Kantowski-Sachs cosmological model filled with viscous fluid in the presence of cosmological term \Lambda. To get a deterministic solution, a condition between metric potentials is used. The viscous coefficient of bulk viscous fluid is assumed to be a power function of mass density, whereas coefficient of shear viscosity is considered proportional to scale of expansion in the model. It is found that the cosmological constant \Lambda is positive and is a decreasing function of time, which is supported by results from recent supernova observations. Some physical and geometrical properties of the models are also discussed.
Exact Peaked Wave Solution Of The Osmosis K(2,2) Equation, Xijun Deng, Libo Han
Exact Peaked Wave Solution Of The Osmosis K(2,2) Equation, Xijun Deng, Libo Han
Turkish Journal of Physics
By using the first-integral method, an exact peaked wave solution to the K(2,2) equation with osmosis dispersion has been obtained directly. The obtained solution agrees well with the previously known solution in the literature. The first integral method is easier and quicker than other traditional techniques. It is shown that the first integral method is a standard and direct method, which may allow us to solve other more complicated solitary wave problems.
Dielectric Properties Of Liquid Systems: The Ideal Complex Permittivity In Liquid Mixtures, Adrian H. Buep
Dielectric Properties Of Liquid Systems: The Ideal Complex Permittivity In Liquid Mixtures, Adrian H. Buep
Turkish Journal of Physics
A general definition for ideal complex permittivity in a liquid mixture was reached by considering a thermodynamically ideal mixture under the effect of an applied harmonic electric field. The resulting definition is independent of any particular dielectric model, as well as the polarity of the components.
Measurements Of K-Shell Fluorescence Yields For Ti, V, Cr, Fe, Co, Ni And Cu Elements And Their Halogen Compounds, Eli̇f Baydaş, Eli̇f Orhan Öz, Mehmet Büyükyildiz
Measurements Of K-Shell Fluorescence Yields For Ti, V, Cr, Fe, Co, Ni And Cu Elements And Their Halogen Compounds, Eli̇f Baydaş, Eli̇f Orhan Öz, Mehmet Büyükyildiz
Turkish Journal of Physics
K-shell fluorescence yields \omega_K were measured for the elements Ti, V, Cr, Fe, Co, Ni, Cu and F and Cl compounds of these elements. Measurements were carried out at 10 keV excitation energy using secondary excitation method. K x-rays emitted by samples were counted by a Si(Li) detector with 160 eV resolution at 5.9 keV. Measurement of K-shell fluorescence yields \omega_K for these elements are compared with earlier experimental results obtained by other methods.
Tau Sleptons And Tau Sneutrino Decays In Mssm Under The Cosmological Bounds, Levent Selbuz, Z. Zekeri̇ya Aydin
Tau Sleptons And Tau Sneutrino Decays In Mssm Under The Cosmological Bounds, Levent Selbuz, Z. Zekeri̇ya Aydin
Turkish Journal of Physics
We present a numerical investigation of the fermionic two-body decays of tau sleptons \tilde \tau_{1,2} and \tau sneutrino in the Minimal Supersymmetric Standard Model with complex parameters. In the analysis we particularly take into account the cosmological bounds imposed by WMAP data. We plot the CP-phase dependences for each fermionic two-body channel of \tilde \tau_{1,2} and \tau sneutrino and speculate about the branching ratios and total (two-body) decay widths. We find that the phase dependences of the decay widths of the third family sleptons are quite significant which can provide viable probes of additional CP sources. We also draw attention …
Conversion Efficiency Calculations For Euv Radiation Emitted From Laser-Produced Tin Plasmas, Betül Atalay, Necla Kenar, Ari̇f Demi̇r
Conversion Efficiency Calculations For Euv Radiation Emitted From Laser-Produced Tin Plasmas, Betül Atalay, Necla Kenar, Ari̇f Demi̇r
Turkish Journal of Physics
Ni-like and Co-like EUV radiation between 11--17 nm emitted from laser produced tin plasmas was modelled by using the hydrodynamic/atomic physics code EHYBRID. The atomic data were obtained using the Cowan code. The effects of driving laser pulse duration and the laser intensity with different wavelengths were investigated. The maximum conversion efficiency was calculated as 13.4% for a 266 nm Nd:YAG laser with 1 \times 10^{13} W/cm^2 pulse intensity and 5 ns pulse duration.
Values Of The Carmichael Function Equal To A Sum Of Two Squares, William D. Banks, Ahmet M. Güloğlu
Values Of The Carmichael Function Equal To A Sum Of Two Squares, William D. Banks, Ahmet M. Güloğlu
Turkish Journal of Mathematics
In this note, we determine the order of growth of the number of positive integers n \le x such that \lambda(n) is a sum of two square numbers, where \lambda(n) is the Carmichael function.
Geodesics Of The Cheeger-Gromoll Metric, Ari̇f A. Salimov, S. Kazimova
Geodesics Of The Cheeger-Gromoll Metric, Ari̇f A. Salimov, S. Kazimova
Turkish Journal of Mathematics
The main purpose of the paper is to investigate geodesics on the tangent bundle with respect to the Cheeger-Gromoll metric.
C1 Modules With Respect To A Hereditary Torsion Theory, Tahi̇re Özen
C1 Modules With Respect To A Hereditary Torsion Theory, Tahi̇re Özen
Turkish Journal of Mathematics
An R-module M is said to be a C1-module if every closed submodule of M is a direct summand. In this paper we introduce and investigate the concept of the \tau-C1 module for a hereditary torsion theory \tau on Mod-R. \tau-C1 modules are a generalization of C1-modules.
Some Properties Of The First Eigenvalue Of The $P(X)$-Laplacian On Riemannian Manifolds, R. A. Mashiyev, Guli̇zar Ali̇soy, Sezai̇ Ogras
Some Properties Of The First Eigenvalue Of The $P(X)$-Laplacian On Riemannian Manifolds, R. A. Mashiyev, Guli̇zar Ali̇soy, Sezai̇ Ogras
Turkish Journal of Mathematics
The main result of the present paper establishes a stability property of the first eigenvalue of the associated problem which deals with the $p(x)$-Laplacian on Riemannian manifolds with Dirichlet boundary condition.
Superconducting State Parameters Of Al-Li Binary Alloys, Aditya M. Vora
Superconducting State Parameters Of Al-Li Binary Alloys, Aditya M. Vora
Turkish Journal of Physics
Theoretical computation of superconducting state parameters (SSP) viz. electron-phonon coupling strength \lambda , Coulomb pseudopotential \mu^* , transition temperature T_C , isotope effect exponent \alpha and effective interaction strength N_o V of face centered cubic Al_{1-C} Li_C binary alloys have been made extensively in the present work using a model potential formalism for the first time. A considerable influence of various exchange and correlation functions on \lambda and \mu^* is found from the present study. The present results of the SSP are found in qualitative agreement with the available experimental data wherever exist.
The Existence Of Triple Positive Solutions Of Nonlinear Four-Point Boundary Value Problem With P-Laplacian, Xiang-Feng Li, Pei-Hao Zhao
The Existence Of Triple Positive Solutions Of Nonlinear Four-Point Boundary Value Problem With P-Laplacian, Xiang-Feng Li, Pei-Hao Zhao
Turkish Journal of Mathematics
This paper deals with the multiplicity results of positive solutions of one-dimensional singular p-Laplace equation (\varphi_p(u'(t)))'+a(t)f(t,u(t),u'(t))=0, 0
An Intelligent Face Features Generation System From Fingerprints, Şeref Sağiroğlu, Necla Özkaya
An Intelligent Face Features Generation System From Fingerprints, Şeref Sağiroğlu, Necla Özkaya
Turkish Journal of Electrical Engineering and Computer Sciences
In this study, a novel intelligent system based on artificial neural networks was designed and introduced for generating faces from fingerprints with high accuracy. The proposed system has a number of modules including two feature enrolment modules for acquiring the fingerprints and faces into the system, two feature extractors for extracting the feature sets of fingerprint and face biometrics, an artificial neural network module that was configured with the help of Taguchi experimental design method for establishing relationships among the biometric features, a face re-constructor for building up face features from the results of the system, and a test module …
Modeling And Calculation Of Electromagnetic Field In The Surroundings Of A Large Power Transformer, Leonardo Strac, Franjo Kelemen, Damir Zarko
Modeling And Calculation Of Electromagnetic Field In The Surroundings Of A Large Power Transformer, Leonardo Strac, Franjo Kelemen, Damir Zarko
Turkish Journal of Electrical Engineering and Computer Sciences
The presented study compares measured and calculated electromagnetic field quantities in the surroundings of a large power transformer with the aim to avoid the necessity of measuring the field on subsequent units and use a computer model instead. The influences of various objects located in the vicinity of the transformer during measurement are also analyzed and are taken into account in a computer model.
Parameter Identification Of A Separately Excited Dc Motor Via Inverse Problem Methodology, Mounir Hadef, Mohamed Rachid Mekideche
Parameter Identification Of A Separately Excited Dc Motor Via Inverse Problem Methodology, Mounir Hadef, Mohamed Rachid Mekideche
Turkish Journal of Electrical Engineering and Computer Sciences
Identification is considered to be among the main applications of inverse theory and its objective for a given physical system is to use data which is easily observable, to infer some of the geometric parameters which are not directly observable. In this paper, a parameter identification method using inverse problem methodology is proposed. The minimisation of the objective function with respect to the desired vector of design parameters is the most important procedure in solving the inverse problem. The conjugate gradient method is used to determine the unknown parameters, and Tikhonov's regularization method is then used to replace the original …