Computer Engineering Commons^™

Speech Recognition Using Ann And Predator-Influenced Civilized Swarm Optimization Algorithm, Teena Mittal, Rajendra Kumar Sharma

Turkish Journal of Electrical Engineering and Computer Sciences

This paper proposes a hybrid optimization technique, predator-influenced civilized swarm optimization, by integrating civilized swarm optimization (CSO) and predator-prey optimization (PPO) techniques. CSO is the integration of the attributes of particle swarm optimization and a society civilization algorithm (SCA). In the SCA, the swarm is divided into a few societies, and each society has its own society leader (SL); other individuals of the society are termed society members. The combination of all such societies forms a civilization, and the best-performing SL becomes the civilization leader (CL). In CSO, SLs and members update their positions through the guidance of their own …

Solar Irradiation Estimator Based On A Self-Calibrated Reference Solar Cell, Touria Hassboun, Lhoussain El Bahir, Youness Aite Driss, Mustapha El Adnani

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper we propose a concept for estimating solar irradiation based on measurements of the current, voltage, and temperature of a photovoltaic (PV) cell. The estimation of the irradiation is obtained by processing these measurements using a PV cell mathematical model combined with a PI controller. Since the PV cell current is very sensitive to the irradiance level, the principle of the method is to force the model to reproduce the same current as that measured on the cell by applying an appropriate irradiance as input, for measured temperature and voltage. The appropriate irradiance, which is the output of …

A New Algorithm For Avoiding Maloperation Of Transformer Restricted Earth Fault Protection Caused By The Transformer Magnetizing Inrush Current And Current Transformer Saturation, Jelisaveta Krstivojevic, Milenko Djuric

Turkish Journal of Electrical Engineering and Computer Sciences

Owing to current transformer (CT) saturation caused by a decaying direct current component in the magnetizing inrush current, the restricted earth fault (REF) protection of a power transformer could maloperate during magnetizing inrush. This paper presents a new transformer restricted earth fault relay algorithm that can prevent false relay tripping and provide proper action during the energization of a faulty transformer. The integral of the product of the signals that are compared is calculated over 1 half-period of the signals. The performance of the proposed algorithm is tested and verified using a large number of transformer energization trials and fault …

Parallel Decoding For Lattice Reduction-Aided Mimo Receiver, Madurakavi Karthikeyan, Djagadeesan Saraswady

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, we propose a modified lattice reduction (LR) for parallel decoding (PD) in multiple input and multiple output (MIMO) systems. Compared with the conventional methods, without any performance loss, the symbols can be estimated in parallel using this LR-PD algorithm. This parallel decoding is achieved through the proposed postrotation matrix. Among the various LR algorithms, LLL has been considered in the analysis of this postrotation matrix. However, this can be applied to any other LR algorithms without any modifications. In simulations, we show that with a minimal number of extra arithmetic operations and without any significant loss in …

An 11-Switch Multilevel Inverter With A Modified Space Vector Modulation, Nasrudin Abd Rahim, Hew Wooi Ping, Jafferi Jamaludin

Turkish Journal of Electrical Engineering and Computer Sciences

This paper proposes a new 3-phase multilevel inverter that is able to generate 7 levels in line-to-line voltage with only 11 switches. The inverter is formed from the 6-switch conventional full-bridge topology with the addition of 5 bidirectional switches in which 2 of them are shared among the three phases. By doing so, the number of power switches can be minimized, thus reducing the complexity in generating and controlling PWM signals. A novel voltage control scheme based on space vector modulation is developed by introducing a virtual vector in every sector of the vector hexagon. This is to overcome the …

Linear Model Of A Three-Phase Shunt Active Power Filter With A Hysteresis Controller, Kadi̇r Vardar, Eyup Akpinar

Turkish Journal of Electrical Engineering and Computer Sciences

In this work, a linear model of a 3-phase active power filter (APF) is obtained to design a DC link proportional--integral (PI) controller. The system is designed on the basis of a TMS320F2812 digital signal processer (DSP). The PI controller is implemented in the program of the DSP. The hysteresis controller and sampling frequency are also taken into account in the linear model. The effect of hysteresis bandwidth, filter inductance, DC link capacitor, and sampling frequency on the stability are investigated by using the Routh--Hurwitz method. The detailed simulation model in MATLAB and experimental results showed that the linear model …

A Switchable Approach To Large Object Allocation In Real-Time Java, Veysel Harun Şahi̇n, Ümi̇t Kocabiçak

Turkish Journal of Electrical Engineering and Computer Sciences

Over the last 20 years object-oriented programming languages and managed run-times like Java have been very popular because of their software engineering benefits. Despite their popularity in many application areas, they have not been considered suitable for real-time programming. Besides many other factors, one of the barriers that prevent their acceptance in the development of real-time systems is the long pause times that may arise during large object allocation. This paper examines different kinds of solutions that have been developed so far and introduces a switchable approach to large object allocation in real-time Java. A synthetic benchmark application that is …

Improving The Srf Method To Compensate Low-Order Harmonics Under Nonsinusoidal Network Voltages, Javad Modarresi, Mehdi Fallah, Eskandar Ghokipour, Mohammad Tavakoli Bina

Turkish Journal of Electrical Engineering and Computer Sciences

Increasing the application of power in electronic devices has increased the harmonics in power systems. Numerous methods like the synchronous reference frame (SRF) and the p-q-based method have been suggested to overcome the effects of these harmonics. The conventional SRF method provides acceptable results in harmonic compensation of high-order harmonics (higher than the fourth order), but the transient response time will be drastically increased in the presence of low-order harmonics due to the existence of a conventional low-pass filter. Furthermore, if the load terminal voltages are distorted, then the conventional SRF method will become unable to implement load current compensation. …

Small Signal Analysis For Dc Bus Voltage Disturbance Resistance Of Voltage Source Converter, Yingjie Wang, Xiaojie Wu, Ping Lu, Yonglei Zhang

Turkish Journal of Electrical Engineering and Computer Sciences

The DC bus voltage of the voltage source converter (VSC) is prone to large fluctuation and even to losing its stability for the large mutation of grid voltage or DC-link loads. First the characteristics of two-step transmission to power in the VSC are analyzed, proving that it is inevitable for DC bus voltage fluctuation to occur when grid voltage or DC-link loads mutate. A new two-step feedforward control strategy is then put forward for curbing the fluctuation, which overcomes the shortcoming by which the traditional feedforward control strategy is affected for the performance of current control. The small signal models …

Empirical Mode Decomposition Application For Short-Term Flicker Severity, Yasemi̇n Önal, Ömer Nezi̇h Gerek, Doğan Gökhan Ece

Turkish Journal of Electrical Engineering and Computer Sciences

In this article, an approach based on empirical mode decomposition (EMD) is suggested in order to calculate short-term flicker severity, Pst, in power systems. EMD is a new signal processing method used for the analysis of nonlinear and nonstationary signals. Pst is an important quantity in the electric power quality index defined by the International Electrotechnical Commission. In the suggested approach, the voltage signal is separated into intrinsic mode function components using EMD. These components are used for calculating the voltage flicker amplitude and frequency, and Pst is calculated as a result of the statistical evaluation of flicker amplitude. EMD …

A Generalized Particle Swarm Optimization Using Reverse Direction Information, Emre Çomak

Turkish Journal of Electrical Engineering and Computer Sciences

In this study, an improved particle swarm optimization (PSO) algorithm, including 4 types of new velocity updating formulae (each is equal to the traditional PSO), was introduced. This algorithm was called the reverse direction supported particle swarm optimization (RDS-PSO) algorithm. The RDS-PSO algorithm has the potential to extend the diversity and generalization of traditional PSO by regulating the reverse direction information adaptively. To implement this extension, 2 new constants were added to the velocity update equation of the traditional PSO, and these constants were regulated through 2 alternative procedures, i.e. max--min-based and cosine amplitude-based diversity-evaluating procedures. The 4 most commonly …

Commutation Angles Adjustment In Srm Drives To Reduce Torque Ripple Below The Motor Base Speed, Ali Shahabi, Amir Rashidi, Milad Afshoon, Seyyed Mortaza Saghaian Nejad

Turkish Journal of Electrical Engineering and Computer Sciences

This paper investigates the problem of high torque ripple in switched reluctance motor (SRM) drives. A method is proposed for below the base speed operation of SRM that determines both the turn-off and the turn-on angles for reducing motor torque ripple. Determination of the turn-off angle is an offline process performed through solving a multiobjective optimization function consisting of two criteria: torque ripple and copper loss. Turn-on angle adjustment, however, is an online process based on the intersection approach of consecutive phase currents, particularly proposed in this paper. Simulation and experimental results are presented to validate the reduction in torque …

Wavefront-Ray Grid Fdtd Algorithm, Mehmet Çi̇ydem

Turkish Journal of Electrical Engineering and Computer Sciences

A finite difference time domain algorithm on a wavefront-ray grid (WRG-FDTD) is proposed in this study to reduce numerical dispersion of conventional FDTD methods. A FDTD algorithm conforming to a wavefront-ray grid can be useful to take into account anisotropy effects of numerical grids since it features directional energy flow along the rays. An explicit and second-order accurate WRG-FDTD algorithm is provided in generalized curvilinear coordinates for an inhomogeneous isotropic medium. Numerical simulations for a vertical electrical dipole have been conducted to demonstrate the benefits of the proposed method. Results have been compared with those of the spherical FDTD algorithm …

A Generalized Design Method For Multifunction Converters Used In A Photovoltaic System, Trung Nhan Nguyen, An Luo

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, a general design method for multifunction converters using photovoltaic systems is proposed. With the proposed converter, the photovoltaic generator can provide flexibility, accuracy, and fast responses in both harmonic suppression and power injection modes in all cases of the grid-connected load. The controller for the proposed converter is designed based on the Lyapunov technique, along with the generalized algorithm for determining the global optimal values of the stability bounds. Therefore, the proposed converter can perform accurately and efficiently in the case of fixed system parameters as well as in the case of varying system parameters. Simulations and …

Prediction-Based Reversible Image Watermarking Using Artificial Neural Networks, Mahsa Afsharizadeh, Majid Mohammadi

Turkish Journal of Electrical Engineering and Computer Sciences

In prediction-based reversible watermarking schemes, watermark bits are embedded in the prediction errors. An accurate prediction results in smaller prediction errors, more efficient embedding, and less distortion for the watermarked image. In this paper, an accurate prediction is made using artificial neural networks. Before the embedding operation, 2 neural networks are trained by the pixel values of the image. Then the trained neural networks predict the pixel values that are used in the embedding operation. Due to the training ability of the neural networks, the prediction will be more accurate than the averaging technique. Experimental results show that the proposed …

Site-Specific Design Optimization Of Horizontal-Axis Wind Turbine Systems Using Pso Algorithm, Ulaş Emi̇noğlu

Turkish Journal of Electrical Engineering and Computer Sciences

Due to the complexity of wind turbine systems (WTSs) containing multiple components, design parameters of a WTS must match each other in order to produce electrical energy at a lower cost and a higher efficiency. In this study, a framework for site-specific design optimization of a horizontal-axis WTS is proposed. It is based on cost reduction and the objective function is the produced energy cost. The cost of energy model proposed by the National Renewable Energy Laboratory is utilized. In order to compute turbine output power that results in annual energy production, a new approach is proposed to model the …

Performance Analysis Of Biogeography-Based Optimization For Automatic Voltage Regulator System, Uğur Güvenç, Ali̇ Hakan Işik, Tuncay Yi̇ği̇t, İbrahi̇m Akkaya

Turkish Journal of Electrical Engineering and Computer Sciences

A self-tuning method to determine the appropriate parameters of a proportional-integral-derivative controller for an automatic voltage regulator (AVR) system using a biogeography-based optimization (BBO) algorithm is proposed in this study. The BBO algorithm was developed based on the theory of biogeography, which describes migration and its results. We propose that the BBO algorithm has a high-quality solution and stable convergence characteristics, and thus it improves the transient response of the controlled system. The performance of the BBO algorithm depends on the transient response, root locus, and Bode analysis. Robustness analysis is done in the AVR system, which is tuned by …

An Analytical Formulation With Ill-Conditioned Numerical Scheme And Its Remedy: Scattering By Two Circular Impedance Cylinders, Emrah Sever, Fati̇h Di̇kmen, Olga Alexandrovna Suvorova, Yury Alexanderovich Tuchkin

Turkish Journal of Electrical Engineering and Computer Sciences

The regularization of the well-known analytical formulation of the monochromatic electromagnetic wave scattering problem from a syvstem with two neighbor impedance circular cylinders is presented. It is the improvement and extension of the work done for scattering from two perfectly conducting circular cylinders. Numerical results show that it is numerically much safer to solve the obtained infinite algebraic system at a lower truncation number also by ensuring the reliability of the solution.

A Discrete Numerical Method For Magnetic Field Determination In Three-Phase Busbars Of A Rectangular Cross-Section, Tomasz Szczegielniak, Zygmunt Piatek, Bernard Baron, Pawel Jablonski, Dariusz Kusiak, Artur Pasierbek

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a discrete numerical computation method for determining the magnetic field distributions in finite-length high-current bus ducts of rectangular busbars. This method is based on the integral equation method and the partial element equivalent circuit method. It takes into account the skin effect and proximity effects, as well as the complete electromagnetic coupling between phase bars and the neutral bar. In particular, the magnetic fields in busbars of unshielded three-phase systems with rectangular phase and neutral busbars and the use of the method are described. Finally, two applications to three-phase unshielded systems busbars are presented.

A New Deployment Method For Electric Vehicle Charging Infrastructure, Bünyami̇n Yağciteki̇n, Mehmet Uzunoğlu, Ari̇f Karakaş

Turkish Journal of Electrical Engineering and Computer Sciences

The fast depletion of fossil fuels, climate change, and global warming have become major worldwide problems and alternatives for conventional transportation have been actively researched in the last decade. Compared to available conventional vehicles, electric vehicles have a leading position due to their environmentally friendly transportation. Recent electric vehicle penetration brings the necessity of a high number of charging stations, which are considered to be established in community areas such as shopping centers, hospitals, commercial areas, university campuses, residential areas, and streets. Deployment planning of charging stations is very important for driver expectations and social and economic impacts of electric …

Comparative Study Of Drive Systems Using Vector-Controlled Pmsm Fed By A Matrix Converter And A Conventional Frequency Converter, Pawel Szczesniak, Konrad Urbanski, Zbigniew Fedyczak, Krzysztof Zawirski

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a comparative study of a drive system with a permanent magnet synchronous motor fed by a matrix converter and a voltage source inverter with diode rectifier stage. A rotor-oriented vector control is implemented in the drive control. Space vector modulation techniques are used for both converters in the output current modulation process. Initial simulation test results and comparison are presented. The advantages of both solutions are indicated. Special attention is given to the drive control in the low speed range. The main aim of this article is to present drive systems with a matrix converter as an …

Novel Approaches To Clustering, Biclustering Algorithms Based On Adaptive Resonance Theory And Intelligent Control, Sejun Kim

Doctoral Dissertations

"The problem of clustering is one of the most widely studied area in data mining and machine learning. Adaptive resonance theory (ART), an unsupervised learning clustering algorithm, is a clustering method that can learn arbitrary input patterns in a stable, fast and self-organizing way. This dissertation focuses on unsupervised learning methods, mostly based on variations of ART.

Hierarchical ART clustering is studied by generating a tree of ART units with GPU based parallelization to provide fast and finesse clustering. Experiment results show that the our method achieves significant training speed increase in generating deep ART trees compared with that from …

An Empirical Investigation Of The Willingness Of Us Intelligence Community Analysts To Contribute Knowledge To A Knowledge Management System (Kms) In A Highly Classified And Sensitive Environment, Robert Hambly

CCAC Theses and Dissertations

Since September 11, 2001, the United States Government (USG) has possessed unparalleled capability in terms of dedicated intelligence and information collection assets supporting the analysts of the Intelligence Community (IC). The USG IC has sponsored, developed, and borne witness to extraordinary advances in technology, techniques, and procedures focused on knowledge harvesting, knowledge sharing, and collaboration. Knowledge, within successful (effective & productive) organizations, exists as a commodity; a commodity that can be created, captured, imparted, shared, and leveraged. The research problem that this study addressed is the challenge of maintaining strong organizational effectiveness and productivity through the use of an information …

Analysis Of Active Power Control Algorithms Of Variable Speed Wind Generators For Power System Frequency Stabilization, Jakub Osmic, Mirza Kusljugic, Elvisa Becirovic, Daniel Toal

Turkish Journal of Electrical Engineering and Computer Sciences

A modified control algorithm of a variable speed wind generator (VSWG) for supporting power system frequency stabilization is presented in this paper. A comparison of the performance of this algorithm with active power control algorithms of VSWGs for supporting power system frequency stabilization, as published in the scientific literature, is also presented. A systematic method of analysis of the modified control algorithm is described in detail. It has been shown that by using the modified control algorithm, the VSWG ''truly'' emulates the inertial response of a conventional steam-generating unit with synchronous generators during the initial/inertial phase of primary frequency control, …

Comparative Performance Evaluation Of Blast Furnace Flame Temperature Prediction Using Artificial Intelligence And Statistical Methods, Yasi̇n Tunçkaya, Etem Köklükaya

Turkish Journal of Electrical Engineering and Computer Sciences

The blast furnace (BF) is the heart of the integrated iron and steel industry and used to produce melted iron as raw material for steel. The BF has very complicated process to be modeled as it depends on multivariable process inputs and disturbances. It is very important to minimize operational costs and reduce material and fuel consumption in order to optimize overall furnace efficiency and stability, and also to improve the lifetime of the furnace within this task. Therefore, if the actual flame temperature value is predicted and controlled properly, then the operators can maintain fuel distribution such as oxygen …

Improved Direct Power Control For 3-Level Ac/Dc Converter Under Unbalanced And/Or Distorted Voltage Source Conditions, Imad Merzouk, Mohamed Lokmane Bendaas

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, an improved direct power control with space vector modulation for a 3-phase 3-level neutral point clamped converter supplied by unbalanced and/or distorted grid voltage is proposed. The main objective of the control scheme is to obtain balanced and sinusoidal input current with unity power factor under nonideal voltage supply. To achieve the control objectives, compensated active and reactive powers are calculated and added to the referencing one. A theoretical analysis of active and reactive power under a nonideal source is clearly demonstrated. In order to calculate the compensated powers, the extraction of positive, negative, and harmonic sequences …

Theoretical Analysis Of Doping Management And Its Effects On Power Scaling, Ami̇ra Tandi̇rovi̇ç Gürsel, Parvi̇z Elahi̇, Fati̇h Ömer İlday, Mustafa Sadetti̇n Özyazici

Turkish Journal of Electrical Engineering and Computer Sciences

No abstract provided.

A New Abc-Based Multiobjective Optimization Algorithm With An Improvement Approach (Ibmo: Improved Bee Colony Algorithm For Multiobjective Optimization), Tahi̇r Sağ, Mehmet Çunkaş

Turkish Journal of Electrical Engineering and Computer Sciences

No abstract provided.

A Robust Bayesian Inference-Based Channel Estimation In Power Line Communication Systems Contaminated By Impulsive Noise, Mohammad Asadpour, Behzad Mozaffari Tazehkand, Hadi Seyedarabi

Turkish Journal of Electrical Engineering and Computer Sciences

No abstract provided.

A Novel Method Of Relieving Congestion In Hybrid Deregulated Market Utilizing Renewable Energy Sources, Joseph Jeslin Drusila Nesamalar, Paramasivam Venkatesh, Sathiasamuel Charles Raja

Turkish Journal of Electrical Engineering and Computer Sciences

No abstract provided.