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2014

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Articles 961 - 990 of 1036

Full-Text Articles in Computer Engineering

Privacy Preserving In Association Rules Using A Genetic Algorithm, Rahat Ali Shah, Sohail Asghar Jan 2014

Privacy Preserving In Association Rules Using A Genetic Algorithm, Rahat Ali Shah, Sohail Asghar

Turkish Journal of Electrical Engineering and Computer Sciences

Association rule mining is one of the data mining techniques used to extract hidden knowledge from large datasets. This hidden knowledge contains useful and confidential information that users want to keep private from the public. Similarly, privacy preserving data mining techniques are used to preserve such confidential information or restrictive patterns from unauthorized access. The pattern can be represented in the form of a frequent itemset or association rule. Furthermore, a rule or pattern is marked as sensitive if its disclosure risk is above a given threshold. Numerous techniques have been used to hide sensitive association rules by performing some …


A New Method For Extraction Of Speech Features Using Spectral Delta Characteristics And Invariant Integration, Hassan Farsi, Samana Kuhimoghadam Jan 2014

A New Method For Extraction Of Speech Features Using Spectral Delta Characteristics And Invariant Integration, Hassan Farsi, Samana Kuhimoghadam

Turkish Journal of Electrical Engineering and Computer Sciences

We propose a new feature extraction algorithm that is robust against noise. Nonlinear filtering and temporal masking are used for the proposed algorithm. Since the current automatic speech recognition systems use invariant-integration and delta-delta techniques for speech feature extraction, the proposed algorithm improves speech recognition accuracy appropriately using a delta-spectral feature instead of invariant integration. One of the nonenvironmental factors that reduce recognition accuracy is the vocal tract length (VTL), leading to a mismatch between the training and testing data. We can use the invariant-integration feature idea for decreasing the VTL effects. The aim of this paper is to provide …


Feature Selection On Single-Lead Ecg For Obstructive Sleep Apnea Diagnosis, Hüseyi̇n Gürüler, Mesut Şahi̇n, Abdullah Feri̇koğlu Jan 2014

Feature Selection On Single-Lead Ecg For Obstructive Sleep Apnea Diagnosis, Hüseyi̇n Gürüler, Mesut Şahi̇n, Abdullah Feri̇koğlu

Turkish Journal of Electrical Engineering and Computer Sciences

Many articles that appeared in the literature agreed upon the feasibility of diagnosing obstructive sleep apnea (OSA) with a single-lead electrocardiogram. Although high accuracies have been achieved in detection of apneic episodes and classification into apnea/hypopnea, there has not been a consensus on the best method of selecting the feature parameters. This study presents a classification scheme for OSA using common features belonging to the time domain, frequency domain, and nonlinear calculations of heart rate variability analysis, and then proposes a method of feature selection based on correlation matrices (CMs). The results show that the CMs can be utilized in …


Vessel Segmentation In Mri Using A Variational Image Subtraction Approach, Ayşe Nurdan Saran, Fati̇h Nar, Murat Saran Jan 2014

Vessel Segmentation In Mri Using A Variational Image Subtraction Approach, Ayşe Nurdan Saran, Fati̇h Nar, Murat Saran

Turkish Journal of Electrical Engineering and Computer Sciences

Vessel segmentation is important for many clinical applications, such as the diagnosis of vascular diseases, the planning of surgery, or the monitoring of the progress of disease. Although various approaches have been proposed to segment vessel structures from 3-dimensional medical images, to the best of our knowledge, there has been no known technique that uses magnetic resonance imaging (MRI) as prior information within the vessel segmentation of magnetic resonance angiography (MRA) or magnetic resonance venography (MRV) images. In this study, we propose a novel method that uses MRI images as an atlas, assuming that the patient has an MRI image …


Performance Evaluation Of A Fuzzy Variable Structure Satellite Attitude Controller Under Sensor Data Delay, Bi̇lgehan Erkal, Hüseyi̇n Demi̇rel Jan 2014

Performance Evaluation Of A Fuzzy Variable Structure Satellite Attitude Controller Under Sensor Data Delay, Bi̇lgehan Erkal, Hüseyi̇n Demi̇rel

Turkish Journal of Electrical Engineering and Computer Sciences

One of the main sources of uncertainties in controlling the attitude of a satellite is the time delays seen in sensor data. Although it is possible to process sensor data to correct the deficiencies caused by delays, it is more suitable to design the controller robust enough to handle uncertainties well. In this study, the attitude of a 3-degrees of freedom satellite model, incorporating uncertainties (both sensor data delay and actuator misplacements), is controlled using a suitably designed fuzzy variable structure controller (FVSC). The performance of the FVSC is evaluated and compared to that of other reference controllers [proportional-derivative (PD), …


Competitive Unit Maintenance Scheduling In A Deregulated Environment Based On Preventing Market Power, Hessam Golmohamadi, Maryam Ramezani, Hamid Falaghi Jan 2014

Competitive Unit Maintenance Scheduling In A Deregulated Environment Based On Preventing Market Power, Hessam Golmohamadi, Maryam Ramezani, Hamid Falaghi

Turkish Journal of Electrical Engineering and Computer Sciences

With the advent of electricity markets, the traditional approach to unit maintenance scheduling (UMS) needs to undergo major changes in order to be compatible with competitive environment structures. The transition from a vertical power system to a competitive structure makes many challenges for policymakers and market designers. In this paper, a new approach to UMS in competitive electricity markets is presented. The main part of this study involves both how to treat generating companies (GENCOs) fairly and how to guarantee power system security during the maintenance scheduling. This paper advances the UMS in the electricity market so that one can …


An Efficient Approach To The Local Optimization Of Finite Electromagnetic Band-Gap Structures, David Duque, Vito Lancellotti, Bastiaan Pieter De Hon, Antonius Tijhuis Jan 2014

An Efficient Approach To The Local Optimization Of Finite Electromagnetic Band-Gap Structures, David Duque, Vito Lancellotti, Bastiaan Pieter De Hon, Antonius Tijhuis

Turkish Journal of Electrical Engineering and Computer Sciences

We propose a methodology based on linear embedding via Green's operators (LEGO) and the eigencurrent expansion method (EEM) to efficiently deal with and locally optimize 2-D electrically large electromagnetic band-gap (EBG) structures. In LEGO terminology, the composite EBG structure is broken up (diakopted) into constitutive elements called ``bricks'' that we characterize through scattering operators by invoking Love's equivalence principle, while, at the same time, the electromagnetic interaction among the bricks is captured by transfer operators. The resulting electromagnetic problem is then succinctly formulated through an integral equation involving the total inverse scattering operator S^{-1} of the structure. To perform local …


Design And Implementation Of An Observer Controller For A Buck Converter, Shenbaga Lakshmi, Sree Renga Raja Jan 2014

Design And Implementation Of An Observer Controller For A Buck Converter, Shenbaga Lakshmi, Sree Renga Raja

Turkish Journal of Electrical Engineering and Computer Sciences

An observer controller for a buck converter is presented. A state feedback gain matrix is derived in order to achieve the stability of the converter and to ensure the robustness of the controller. A load estimator is designed to estimate the unmeasurable variables and to obtain the zero output voltage error. A pulse-width modulation scheme is adopted to obtain the output voltage regulation. In order to improve the transitory response and dynamic constancy of the converter, the controller parameters are designed based on the current mode control. The design is evaluated and verified using MATLAB/Simulink. An experimental set-up is done …


Continuity Of Currents Across Neighboring Cells In Pmm Analysis Of Thin-Wire Grids, Sena Esen Bayer Keski̇n, Ahmet Ari̇f Ergi̇n Jan 2014

Continuity Of Currents Across Neighboring Cells In Pmm Analysis Of Thin-Wire Grids, Sena Esen Bayer Keski̇n, Ahmet Ari̇f Ergi̇n

Turkish Journal of Electrical Engineering and Computer Sciences

This article presents a new approach for the analysis of electromagnetic scattering from a rectangular wire mesh. In this sense, a basis function that considers the flow of a current from one cell to the next is proposed in light of Floquet's theorem. The proposed basis function enables the use of periodic method of moments in frequency-selective surfaces composed of thin wires in the case of a system having a connection with neighboring cells, such as thin-wire grids. The validity of the proposed solution approach is tested in 2 distinct cases (with and without a neighbor connection) for scattered fields. …


Neuro-Fuzzy Network Approach For Modeling Submicron Mosfets: Application To Mosfet Subcircuit Simulation, Amirhossein Abdollahinohoji, Fardad Farokhi, Majid Zamani Jan 2014

Neuro-Fuzzy Network Approach For Modeling Submicron Mosfets: Application To Mosfet Subcircuit Simulation, Amirhossein Abdollahinohoji, Fardad Farokhi, Majid Zamani

Turkish Journal of Electrical Engineering and Computer Sciences

A neuro-fuzzy network approach is developed to model the nonlinear behavior of submicron metal-oxide semiconductor field-effect transistors (MOSFETs). The proposed model is trained and implemented as a MOSFET in a software environment. The training data are obtained through various simulations of a MOSFET Berkeley short channel insulated-gate field-effect transistor model 3 (BSIM3) in HSPICE, and the trained model is utilized to simulate the MOSFET device. The obtained result shows good and noticeable agreement between the numerical result of the original model in HSPICE and the neuro-fuzzy approach in the device and subcircuit modeling.


Bi Input-Extended Kalman Filter-Based Speed-Sensorless Control Of An Induction Machine Capable Of Working In The Field-Weakening Region, Remzi̇ İnan, Murat Barut Jan 2014

Bi Input-Extended Kalman Filter-Based Speed-Sensorless Control Of An Induction Machine Capable Of Working In The Field-Weakening Region, Remzi̇ İnan, Murat Barut

Turkish Journal of Electrical Engineering and Computer Sciences

This study introduces a novel bi input-extended Kalman filter (BI-EKF)-based speed-sensorless direct vector control (DVC) of an induction motor (IM). The proposed BI-EKF-based estimator includes online estimations of the stator stationary axis components of the stator currents, i_{s\alpha} and i_{s\beta}; stator stationary axis components of the rotor flux, \varphi_{r\alpha} and \varphi_{r\beta}; rotor angular velocity, \omega_m; stator resistance, R_s; rotor resistance, R_r; and load torque t_L, as well as the magnetizing inductance, L_m, by only supposing that the stator phase currents and voltages are measured. Thus, the speed-sensorless DVC of the IM with the inclusion of the proposed estimator is able …


Control Of Svc Based On The Sliding Mode Control Method, Ercan Köse, Hakan Kizmaz, Kadi̇r Abaci, Saadetti̇n Aksoy Jan 2014

Control Of Svc Based On The Sliding Mode Control Method, Ercan Köse, Hakan Kizmaz, Kadi̇r Abaci, Saadetti̇n Aksoy

Turkish Journal of Electrical Engineering and Computer Sciences

A genetic algorithm (GA)-based sliding mode controller is proposed to improve the voltage stability of a power system with a static var compensator. The proposed controller is examined for improving the load bus voltage, which changes under different demanding powers, and its performance for transient analysis is compared with the Ziegler--Nichols proportional-integral (ZNPI), Lyapunov-based sliding mode control (LASMC), and GA-based proportional-integral-derivative (GAPID) controllers. The dynamic equations, consisting of a 2-bus nonlinear system, are converted to a mathematical description of sliding mode techniques. The optimum values of the sliding mode controller and proportional-integral-derivative (PID) coefficients that are required are calculated using …


Multiple-Global-Best Guided Artificial Bee Colony Algorithm For Induction Motor Parameter Estimation, Abdul Ghani Abro, Junita Mohamad Saleh Jan 2014

Multiple-Global-Best Guided Artificial Bee Colony Algorithm For Induction Motor Parameter Estimation, Abdul Ghani Abro, Junita Mohamad Saleh

Turkish Journal of Electrical Engineering and Computer Sciences

An induction motor is the most commonly used motor in industry today. Motor circuit parameters are essential for designing, evaluating performance, and controlling the applications of the motor. However, it is difficult to measure the electric parameters, e.g., resistance and reactance, of induction motors accurately. Therefore, researchers have noted the parameter estimation of induction motors as an essential optimization problem. The artificial bee colony (ABC) algorithm is an efficient element of bioinspired optimization algorithms and has been successfully applied in numerous engineering applications. However, the ABC algorithm suffers from slow convergence and poor exploitation. Additionally, there are bleak chances of …


Removing Random-Valued Impulse Noise In Images Using A Neural Network Detector, İlke Türkmen Jan 2014

Removing Random-Valued Impulse Noise In Images Using A Neural Network Detector, İlke Türkmen

Turkish Journal of Electrical Engineering and Computer Sciences

This paper proposes a new method using an artificial neural network to remove random-valued impulse noise (RVIN) in images. The inputs of the neural model used to detect the RVIN are formed using basic and related gradient values. The detection of the noisy pixels is realized in 3 phases using the proposed neural detector. In order to obtain a more robust detector, 2 different networks, which are trained with an artificial training image corrupted with high and low clutter densities, are used. The extensive simulation results show that the proposed method is significantly better than the compared filters in terms …


Robust Stability Of Linear Uncertain Discrete-Time Systems With Interval Time-Varying Delay, Mehmet Nur Alpaslan Parlakçi Jan 2014

Robust Stability Of Linear Uncertain Discrete-Time Systems With Interval Time-Varying Delay, Mehmet Nur Alpaslan Parlakçi

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a robust stability problem for linear uncertain discrete-time systems with interval time-varying delay and norm-bounded uncertainties. First, a necessary and sufficient stability condition is obtained by employing a well-known lifting method and switched system approach for nominal discrete-time delay systems. Both the stability method of checking the characteristic values inside the unit circle and a Lyapunov function-based stability result are taken into consideration. Second, a simple Lyapunov--Krasovskii functional (LKF) is selected, and utilizing a generalized Jensen sum inequality, a sufficient stability condition is presented in the form of linear matrix inequalities. Third, a novel LKF is proposed …


Perceptual Quality Evaluation Of Asymmetric Stereo Video Coding For Efficient 3d Rate Scaling, Nükhet Özbek, Gi̇zem Ertan, Oktay Karakuş Jan 2014

Perceptual Quality Evaluation Of Asymmetric Stereo Video Coding For Efficient 3d Rate Scaling, Nükhet Özbek, Gi̇zem Ertan, Oktay Karakuş

Turkish Journal of Electrical Engineering and Computer Sciences

In 3D perception, the binocular suppression of the human vision, perceiving high quality 3D video in the case of a view in higher quality, can be exploited in asymmetric stereo video coding for efficient 3D rate scaling. Hence, the best stereo rate-visual distortion performance may be gained by asymmetric coding, which is the reduction of the spatial and/or quantization resolution of the low-quality view, while keeping the high-quality view in full resolution. However, how to determine the level of asymmetry and what type of scaling should be chosen are still in question. In this work, we try to assess the …


Optimal Operation Management Of Microgrids Using The Point Estimate Method And Firefly Algorithm While Considering Uncertainty, Sirus Mohammadi, Babak Mozafari, Soodabeh Solimani Jan 2014

Optimal Operation Management Of Microgrids Using The Point Estimate Method And Firefly Algorithm While Considering Uncertainty, Sirus Mohammadi, Babak Mozafari, Soodabeh Solimani

Turkish Journal of Electrical Engineering and Computer Sciences

This paper analyzes the behavior of Hong's point estimate method to account for uncertainties in probabilistic energy management systems to optimize the operation of a microgrid (MG). These uncertainties may arise from different sources, such as the market prices, load demands, and electric power generation of wind farms and photovoltaic systems. Point estimate methods constitute a remarkable tool to handle stochastic power system problems because good results can be achieved using the same routines as those corresponding to deterministic problems, while keeping the computational burden low. The problem is formulated as a nonlinear constraint optimization problem to minimize the total …


Source Microphone Identification From Speech Recordings Based On A Gaussian Mixture Model, Ömer Eski̇dere Jan 2014

Source Microphone Identification From Speech Recordings Based On A Gaussian Mixture Model, Ömer Eski̇dere

Turkish Journal of Electrical Engineering and Computer Sciences

Microphone identification is a specific type of media forensics that investigates whether it is possible to identify the source microphone from speech recordings. The main aim of this study is to find out which of the several feature extraction techniques are best suited to the source microphone identification systems. We perform microphone identification experiments with 16 different microphones using 3 datasets. In order to improve the results on the datasets, we also investigate the important parameters that may affect the microphone identification performance. Our experimental results show that the proposed method is comparable to the existing studies in a closed-set …


Retinal Image Analysis Using Multidirectional Functors Based On Geodesic Conversions, Saleh Shahbeig Jan 2014

Retinal Image Analysis Using Multidirectional Functors Based On Geodesic Conversions, Saleh Shahbeig

Turkish Journal of Electrical Engineering and Computer Sciences

A retinal image contains vital information. Extracting these features is the first and most important step in the analysis of retinal images for various applications of medical or human recognition. In this study, a morphological-based blood vessel extraction algorithm using adaptive-local analysis from colored retinal images is proposed. In this algorithm, by applying the appropriate morphology functors and local histogram stretching on the retinal images, the brightness of the images is considerably uniformed. Furthermore, curvelet transform (CT) is used to enhance the retinal images by highlighting the edges of the images in various scales and directions and by the adaptive …


Recurrent Wavelet Neural Network Control Of A Pmsg System Based On A Pmsm Wind Turbine Emulator, Chih Hong Lin Jan 2014

Recurrent Wavelet Neural Network Control Of A Pmsg System Based On A Pmsm Wind Turbine Emulator, Chih Hong Lin

Turkish Journal of Electrical Engineering and Computer Sciences

A recurrent wavelet neural network (NN)-controlled 3-phase permanent magnet synchronous generator system (PMSG), which is direct-driven by a permanent magnet synchronous motor (PMSM) based on a wind turbine emulator, is proposed to control the output values of a rectifier (or AC to DC power converter) and inverter (or DC to AC power converter) in this study. First, a closed-loop PMSM drive control based on a wind turbine emulator is designed to generate the maximum power for the PM synchronous generator (PMSG) system according to different wind speeds. Next, the rotor speed of the PMSG, the DC bus voltage, and the …


Impact Of Plug-In Hybrid Electric Vehicle Charging/Discharging Management On A Microgrid, Kiamars Kaveh, Seyed Mehdi Hakimi, Seyed Masoud Moghaddas-Tafreshi, Fazllolah Naseri Jan 2014

Impact Of Plug-In Hybrid Electric Vehicle Charging/Discharging Management On A Microgrid, Kiamars Kaveh, Seyed Mehdi Hakimi, Seyed Masoud Moghaddas-Tafreshi, Fazllolah Naseri

Turkish Journal of Electrical Engineering and Computer Sciences

Plug-in hybrid electric vehicles (PHEVs) may replace conventional vehicles in most urban areas and populated cities due to their lower levels of air pollution compared to internal combustion engine (ICE) vehicles. PHEVs can increase the ability of residential complexes to participate in demand-side management, as well. This paper explores the potential of PHEVs as a flexible load in order to satisfy 2 main issues: increasing the penetration rate of renewable energy in a microgrid and increasing the load factor. In this study, 3 scenarios for managing PHEV charging and discharging are considered. The first scenario connects PHEVs to the grid …


Discovery Of Hydrometeorological Patterns, Mete Çeli̇k, Fi̇li̇z Dadaşer Çeli̇k, Ahmet Şaki̇r Dokuz Jan 2014

Discovery Of Hydrometeorological Patterns, Mete Çeli̇k, Fi̇li̇z Dadaşer Çeli̇k, Ahmet Şaki̇r Dokuz

Turkish Journal of Electrical Engineering and Computer Sciences

Hydrometeorological patterns can be defined as meaningful and nontrivial associations between hydrological and meteorological parameters over a region. Discovering hydrometeorological patterns is important for many applications, including forecasting hydrometeorological hazards (floods and droughts), predicting the hydrological responses of ungauged basins, and filling in missing hydrological or meteorological records. However, discovering these patterns is challenging due to the special characteristics of hydrological and meteorological data, and is computationally complex due to the archival history of the datasets. Moreover, defining monotonic interest measures to quantify these patterns is difficult. In this study, we propose a new monotonic interest measure, called the hydrometeorological …


Simultaneous Identification And Correction Of Measurement And Branch Parameter Errors, Mehdi Ahmadi Jirdehi, Mehrdad Tarafdar Hagh, Kazem Zare Jan 2014

Simultaneous Identification And Correction Of Measurement And Branch Parameter Errors, Mehdi Ahmadi Jirdehi, Mehrdad Tarafdar Hagh, Kazem Zare

Turkish Journal of Electrical Engineering and Computer Sciences

The performance of the state estimation (SE) depends on the accuracy of the received measured data, as well as the parameter data of the power system. In this paper, a new algorithm is proposed for the simultaneous identification and correction of measurement and branch parameter errors (series and shunt admittances) in the power system SE problem. The proposed method uses Lagrange multipliers for the identification and correction of branch parameter errors without the need for a-priori specification of suspect parameter vectors. Erroneous measurements and branch parameter values can be corrected using the proposed method to estimate the measurement and branch …


Shuffled Frog Leaping Algorithm Optimization For Ac--Dc Optimal Power Flow Dispatch, Abolfazl Rahiminejad, Arash Alimardani, Behrooz Vahidi, Seyed Hossein Hosseinian Jan 2014

Shuffled Frog Leaping Algorithm Optimization For Ac--Dc Optimal Power Flow Dispatch, Abolfazl Rahiminejad, Arash Alimardani, Behrooz Vahidi, Seyed Hossein Hosseinian

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, a simple-implemented and reliable AC--DC optimal power flow (OPF) is proposed. Although high-voltage direct current (HVDC) transmission lines are being increasingly used in power systems, new optimization algorithms such as evolutionary and memetic algorithms, which never stick in local minimum, so far have not been implemented in the AC--DC OPF problem. An evolutionary algorithm known as the shuffled frog leaping algorithm (SFLA) is proposed in this paper to solve the OPF dispatch in an AC--DC power system (including both high-voltage alternating current and HVDC transmission lines). The implementation of the AC--DC OPF with these kinds of methods …


Multifunction Converter Based On Lyapunov Function Used In A Photovoltaic System, Trung Nhan Nguyen, An Luo Jan 2014

Multifunction Converter Based On Lyapunov Function Used In A Photovoltaic System, Trung Nhan Nguyen, An Luo

Turkish Journal of Electrical Engineering and Computer Sciences

The development of distributed generations (DGs) is essential to help solve energy crises and improve the reliability of electricity supplies. However, the involvement of a DG in a grid along with an increase of the nonlinear load will reduce the power quality. To solve this problem, we want the converter used in the DG to work flexibly, intelligently, and more accurately. To contribute to the improvement of quality of the DG, this paper proposes a multifunction converter (MFC) model. With the proposed model, the photovoltaic generator, which can be operated at harmonic suppression, and the power injection are more flexible …


Fuzzy Impedance And Force Control Of A Stewart Platform, Selçuk Ki̇zi̇r, Zafer Bi̇ngül Jan 2014

Fuzzy Impedance And Force Control Of A Stewart Platform, Selçuk Ki̇zi̇r, Zafer Bi̇ngül

Turkish Journal of Electrical Engineering and Computer Sciences

A new, simple, and effective control method is proposed for the position-based impedance and force control of a Stewart platform (SP). The control approach can be divided into 3 parts, namely position control in free space, impedance control in contact, and force control. An impedance filter is developed to achieve the desired behavior between the position and force. The gain of the filter is modified by a fuzzy logic proportional-integral-derivative controller. Kinematic and dynamic models of the SP are simulated in a MATLAB/Simulink environment. Several real-time experiments are conducted with the SP developed in our laboratory. The results of the …


Fuzzy Logic Approach To Henry Factor For Distributed Feedback Laser Case, Abdullah Çavuşoğlu Jan 2014

Fuzzy Logic Approach To Henry Factor For Distributed Feedback Laser Case, Abdullah Çavuşoğlu

Turkish Journal of Electrical Engineering and Computer Sciences

In this study, a simple approach for intelligent modeling of the Henry factor (\alpha-alpha parameter, antiguiding factor, phase-amplitude coupling factor) or the so-called linewidth enhancement factor, which is an actual analysis and design parameter for semiconductor laser diodes and optical communication systems, is proposed based on the fuzzy logic (FL) phenomenon. The proposed FL-based model easily computes the Henry factor in terms of different wavelengths and injection current levels (i.e. the inputs of the model). The experimental data belong to a distributed feedback laser, obtained from amplified spontaneous emission spectra, which is among the techniques required for the characterization of …


Model-Based Robust Chaotification Using Sliding Mode Control, Aykut Kocaoğlu, Cüneyt Güzeli̇ş Jan 2014

Model-Based Robust Chaotification Using Sliding Mode Control, Aykut Kocaoğlu, Cüneyt Güzeli̇ş

Turkish Journal of Electrical Engineering and Computer Sciences

Chaos is a complex behavior of dynamical nonlinear systems that is undesirable in most applications and should be controlled; however, it is desirable in some situations and should be generated. In this paper, a robust chaotification scheme based on sliding mode control is proposed for model based chaotification. A continuous time single input observable system is considered such that it is subject to parameter uncertainties, nonlinearities, noises, and disturbances, which are all additive to the input and can be modeled as an unknown function but bounded by a known function. The designed dynamical state feedback control law forces the system …


Performance Evaluation Of The Wave Atom Algorithm To Classify Mammographic Images, Nebi̇ Gedi̇k, Ayten Atasoy Jan 2014

Performance Evaluation Of The Wave Atom Algorithm To Classify Mammographic Images, Nebi̇ Gedi̇k, Ayten Atasoy

Turkish Journal of Electrical Engineering and Computer Sciences

The most common type of cancer seen in women is breast cancer. To enable recovery from this severe disease, monitoring and early detection must be provided, and related precautions must be taken as a first step. During diagnosis, some cases may be overlooked due to fatigue and eyestrain, because the determination of abnormalities is a repetitive procedure. In this study, a computer-aided diagnosis (CAD) system, using the wave atom transform (WAT) algorithm and support vector machine (SVM), is proposed to evaluate mammography images. During the process, the region of interest (ROI) is defined before applying the method. The system includes …


A New Edge-Preserving Algorithm Based On The Cie- Lu'v' Color Space For Color Contrast Enhancement, Mohammad Zolfaghari, Mehran Yazdi Jan 2014

A New Edge-Preserving Algorithm Based On The Cie- Lu'v' Color Space For Color Contrast Enhancement, Mohammad Zolfaghari, Mehran Yazdi

Turkish Journal of Electrical Engineering and Computer Sciences

Image segmentation and edge detection are the most important presteps in machine vision, and their successfulness can affect the success of the next steps. In this paper, the performance of the Trahanias edge detector in different color spaces, such as RGB, YCbCr, HSI, and CIE Lu'v', is compared in order to find the best color space for image segmentation and edge detection. We then offer an efficient edge-preserving algorithm for color contrast enhancement in the CIE Lu'v' space. The proposed algorithm can increase the color contrast, which causes a remarkable improvement in image segmentation and edge detection in the CIE …