A Novel Direct Torque Control Using Second Order Continuous Sliding Mode Of A Doubly Fed Induction Generator For A Wind Energy Conversion System, Zinelaabidine Boudjema, Rachid Taleb, Youcef Djeriri, Adil Yahdou
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper a new robust direct torque control strategy based on second order continuous sliding mode and space vector modulation of a doubly fed induction generator integrated in a wind energy conversion system is presented. The conventional direct torque control (C-DTC) with hysteresis regulators has significant flux and torque ripples at steady-state operation and also the switching frequency varies in a wide range. The proposed DTC technique based on second order continuous sliding mode control reduces flux, current, and torque ripples. It also narrows down the switching frequency variations in induction machine control. Two different sliding surfaces such as …
A Methodology To Include Real-Life Failure Data In The Failure Rate Estimation Of Power Distribution Systems,
2017
TÜBİTAK
A Methodology To Include Real-Life Failure Data In The Failure Rate Estimation Of Power Distribution Systems, Mojtaba Gilvanejad, Hossein Askarian Abyaneh, Kazem Mazlumi
Turkish Journal of Electrical Engineering and Computer Sciences
Random failure rates are usually assumed as constant values in reliability calculations. In this paper, this topic is investigated using stochastic models of uncertain phenomena like lightning, cold load pickup, and overloading, which result in random failures. An algorithm is developed to estimate the random failure rates in distribution networks during their lifetime. This algorithm stochastically generates the random failures as well as sustained failures as a result of equipment wear-out state due to the aging process and finally estimates the total number of temporary/sustained failures in a period of the network lifetime. The results of applying this algorithm to …
Experimental Evaluation And Fdtd Method For Predicting Electromagnetic Fields In The Near Zone Radiated By Power Converter Systems, Mohammed Laour, Redouane Tahmi, Christian Vollaire
Turkish Journal of Electrical Engineering and Computer Sciences
This paper presents the study of conducted electromagnetic interference (EMI) currents flowing through the power cables of a DC-DC converter system and its correlation with the near field radiated from these cables. The radiated emission measurement contains a common mode (CM) and a differential mode (DM), and accurate separation of the radiated emissions of these two modes is necessary. The finite-difference time-domain (FDTD) method is used to predict the electromagnetic radiation caused by CM currents and DM currents. An experimental bench has been designed to allow access to the measurement of EMI disturbances at various sensitive places. The CM and …
Whole Body Motion Control Of Humanoid Robots Using Bilateral Control,
2017
TÜBİTAK
Whole Body Motion Control Of Humanoid Robots Using Bilateral Control, Emre Sariyildiz, Hakan Temeltaş
Turkish Journal of Electrical Engineering and Computer Sciences
This paper deals with the whole body motion control problem of humanoid robots by using automatic and bilateral control methods. Advanced motion controllers are proposed so that human daily life activities, such as walking on an uneven terrain and contacting an unknown object, can be performed. It is shown that the uncertainty of environmental impedance variation is one of the main challenging issues in the design of the automatic control systems, i.e. a humanoid robot may easily lose its stability when it contacts an unstructured environment. A novel bilateral control method is proposed for humanoid robots so as to overcome …
Ionolab-Ray: A Wave Propagation Algorithm For Anisotropic And Inhomogeneous Ionosphere,
2017
TÜBİTAK
Ionolab-Ray: A Wave Propagation Algorithm For Anisotropic And Inhomogeneous Ionosphere, Esra Erdem, Feza Arikan
Turkish Journal of Electrical Engineering and Computer Sciences
A high-frequency (HF) radio wave propagation model based on ray tracing for anisotropic, inhomogeneous, and time-varying ionosphere is developed to form the basis for a user-friendly modular algorithm. The algorithm IONOLAB-RAY applies the principles of ray tracing through the spherical 3D grid model of the ionosphere. The physical parameters of the ionosphere in each voxel are obtained from the ionosphere model IRI-Plas-G. The refractive index of each voxel is calculated with the Appleton-Hartree formula, which includes electron cyclotron frequency, collision frequency, and anisotropicity due to the geomagnetic field. The developed propagation algorithm allows the input of total electron content (TEC) …
Optimal Design Of Voltage Regulators For Static Excitation System In Synchronous Generator To Reduce Shaft-Induced Voltage,
2017
TÜBİTAK
Optimal Design Of Voltage Regulators For Static Excitation System In Synchronous Generator To Reduce Shaft-Induced Voltage, Mahmoud Samieimoghaddam, Mohammad Tavakoli Bina, Masoud Aliakbar Golkar, Shokrollah Shokrikojoori
Turkish Journal of Electrical Engineering and Computer Sciences
Long-term shaft-induced voltage could harm synchronous generators, specifically their bearings and insulators. This paper investigates the reduction of shaft-induced voltage using both a passive filter and an active voltage regulator. An RLC circuit is used as a passive filter, and a DC-DC buck converter is used as an active voltage regulator. As a result, they remove high-frequency spikes, leading to the reduction of shaft-induced voltage. Buck converters show minimum-phase behavior and can pose as stable-casual converters. A 5 kW synchronous generator was considered for the laboratory setup in which a static excitation system using a 6-pulse thyristor rectifier supplies the …
Intrusion Detection In Network Flows Based On An Optimized Clustering Criterion,
2017
TÜBİTAK
Intrusion Detection In Network Flows Based On An Optimized Clustering Criterion, Jaber Karimpour, Shahriar Lotfi, Aliakbar Tajari Siahmarzkooh
Turkish Journal of Electrical Engineering and Computer Sciences
Graph-based intrusion detection approaches consider the network as a graph and detect anomalies based on graph metrics. However, most of these approaches succumb to the cluster-based behavior of the anomalies. To resolve this problem in our study, we use flow and graph-clustering concepts to create a data set first. A new criterion related to the average weight of clusters is then defined and a model is proposed to detect attacks based on the above-mentioned criterion. Finally, the model is evaluated using a DARPA data set. Results show that the proposed approach detects the attacks with high accuracy relative to methods …
Techno-Economic Analysis Using Different Types Of Hybrid Energy Generation For Desert Safari Camps In Uae,
2017
TÜBİTAK
Techno-Economic Analysis Using Different Types Of Hybrid Energy Generation For Desert Safari Camps In Uae, Ali Aziz
Turkish Journal of Electrical Engineering and Computer Sciences
Remote areas in UAE are still fully powered by diesel generators. The rapid rise in the prices of petroleum products and environmental concerns have led to demand for hybrid renewable energy generators. Advances in renewable energy technologies impart further impetus to techno-economic power production. Protecting the landscape and demography of the desert by optimizing the power supply cost via an efficient hybrid power system is the key issue. Simulation results on the cross utilization of a photovoltaic/wind/battery/fuel-cell hybrid-energy source to power the off-grid living space are presented. Simultaneous exploitation of different renewable energy sources to power off-grid applications together with …
A Steganographic Approach To Hide Secret Data In Digital Audio Based On Xor Operands Triplet Property With High Embedding Rate And Good Quality Audio, Krishna Bhowal, Debasree Chanda Sarkar, Sushanta Biswas, Partha Pratim Sarkar
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, a unique and transparent data hiding algorithm based on XOR operands triplet (XOT) is proposed. In XOT, an XOR operation applied on any two members of a triplet provides the third member of the same triplet. Taking advantage of the low computational complexity and fascinating properties of the XOR operator, it is possible to embed 4-ary secret digits with negligible changes in the host digital audio. The proposed scheme has been designed to ensure that a minimum number of bit alterations happen in the host digital audio during the data hiding process, which also increases the security …
A Neuro-Fuzzy Controller For Grid-Connected Heavy-Duty Gas Turbine Power Plants,
2017
TÜBİTAK
A Neuro-Fuzzy Controller For Grid-Connected Heavy-Duty Gas Turbine Power Plants, Mohamed Iqbal Mohamed Mustafa, Joseph Xavier Rayappan, Kanakaraj Jagannathan
Turkish Journal of Electrical Engineering and Computer Sciences
Frequent load fluctuation and set-point variation may affect the stability of grid-connected heavy-duty gas turbine power plants. To overcome such problems, a novel neuro-fuzzy controller is proposed in this paper for single-shaft heavy-duty gas turbines ranging from 18.2 MW to 106.7 MW. A neuro-fuzzy controller was developed using a hybrid learning algorithm and the effectiveness of the controller for all heavy-duty gas turbine plants (5, 6, 7, and 9 series) is demonstrated against load disturbance and set-point variation in a grid-connected environment. Various time domain specifications and performance index criteria of the neuro-fuzzy controller are compared with that of a …
A Switched Current Controller With Commutation Delay Compensation For The Reduction Of Commutation Torque Ripple In Bldcm Drives, Türker Türker, Ihsan Obayes Khudhair Khudhair
Turkish Journal of Electrical Engineering and Computer Sciences
The mathematical model of the equivalent circuit of a brushless DC motor switches during the operation due to commutation. This issue causes a sudden ripple in the output torque, which is called commutation torque ripple. Brushless DC motor drives suffer from commutation torque ripple, affecting the performance of the motor in practical applications. A discrete-time switched controller is proposed to reduce the commutation torque ripple in brushless DC motor drives. The proposed controller is a combination of two distinct controllers designed for two different working regions of brushless DC motors. In addition, the commutation delay is also considered in the …
Extraction Of Geometric And Prosodic Features From Human-Gait-Speech Data For Behavioral Pattern Detection: Part I,
2017
TÜBİTAK
Extraction Of Geometric And Prosodic Features From Human-Gait-Speech Data For Behavioral Pattern Detection: Part I, Raj Kumar Patra, Tilendra Shishir Sinha, Ravi Prakash Dubey
Turkish Journal of Electrical Engineering and Computer Sciences
In this work, we extract prosodic features from subjects while they are talking while walking using human-gait-speech data. These human-gait-speech data are separated into 1D data (human-speech) and 2D data (human-gait) using the adaptive-lifting scheme of wavelet transform. We carry out extraction of prosodic features from human-speech data, such as speech duration, pitch, speaking rate, and speech momentum, using five different natural languages (Hindi, Bengali, Oriya, Chhattisgarhi, and English) for the detection of behavioral patterns. These behavioral patterns form real-valued measured parameters, stored in a knowledge-based model called the human-gait-speech model. Extraction of geometrical features from human-gait data, such as …
Temporal Preconditioners For Marching-On-In-Time-Based Time Domain Integral Equation Solvers,
2017
TÜBİTAK
Temporal Preconditioners For Marching-On-In-Time-Based Time Domain Integral Equation Solvers, Hüseyi̇n Arda Ülkü
Turkish Journal of Electrical Engineering and Computer Sciences
Temporal preconditioners to stabilize the marching-on-in-time (MOT)-based time domain integral equation (TDIE) solvers are proposed. Exponentially decaying functions are used as temporal preconditioners and the proposed scheme is applied to analyze scattering from perfect electrically conducting objects using the second-order formulation. The effectiveness of the proposed scheme is demonstrated via numerical examples. It is shown that the temporal preconditioners stabilize the MOT system and the solution. In addition, the initial condition problem of TDIEs is investigated by extending the second-order formulation of the time domain electric field integral equation to the time domain magnetic and combined field integral equations.
Fuzzy Support Vector Machine Based On Hyperbolas Optimized By The Quantum-Inspired Gravitational Search Algorithm,
2017
TÜBİTAK
Fuzzy Support Vector Machine Based On Hyperbolas Optimized By The Quantum-Inspired Gravitational Search Algorithm, Feng Ni, Yuzhu He, Fei Jiang
Turkish Journal of Electrical Engineering and Computer Sciences
Fuzzy support vector machines (FSVMs) are known for their excellent antinoise performance, but there is no general rule when the fuzzy membership function (FMF) is set up. A novel FSVM based on hyperbolas optimized by the quantum-inspired gravitational search algorithm (QGSH-FSVM) is proposed to handle this question. In the proposed QGSH-FSVM, the FMF is defined by two disparate hyperbolas, whose eccentricities are optimized by the quantum-inspired gravitational search algorithm. A variable called diversity, revealing the percentage of a sample in different classes, is proposed to distinguish outliers or noises from valid samples. Experimental results confirm that the QGSH-FSVM is able …
Bandwidth Allocation For Multiple Iptv Users Sharing The Same Link: A Case Study Of Telecom Of Kosovo,
2017
TÜBİTAK
Bandwidth Allocation For Multiple Iptv Users Sharing The Same Link: A Case Study Of Telecom Of Kosovo, Arianit Maraj, Adrian Shehu, Dardan Maraj, Ruzhdi Sefa
Turkish Journal of Electrical Engineering and Computer Sciences
Almost all operators today are facing constant requests for multiple video services in a single household. In these situations, video services have to compete for finite network bandwidth and other equipment resources. Each of them requires different bandwidth capacities. This dynamic behavior can jeopardize both quality of service and quality of experience. One should keep in mind that some video channels require more bandwidth than others. Telecom of Kosovo (TK) is facing the same issues. The encoders at TK are not scalable and they treat all video streams equally, without taking into consideration the fact that some video streams require …
Effect Of Uniform And Dolph-Chebyshev Excitations On The Performance Of Circular Array Antennas,
2017
TÜBİTAK
Effect Of Uniform And Dolph-Chebyshev Excitations On The Performance Of Circular Array Antennas, Mohan Kachalai Narasimman, Yogesh Kumar Choukiker, Srinivasa Rao Zinka, Kannadassan Dhanaraj
Turkish Journal of Electrical Engineering and Computer Sciences
This paper presents the design and simulation of microstrip circular antenna arrays and studies the effect of excitation with uniform and Dolph--Chebyshev distribution. With side lobe level of 20 dB and 8 microstrip circular patches, the circular array has been demonstrated with minimum grating lobes. The effects of patch and antenna array length on directivity, radiation patterns, and side lobe are also studied in detail. It is found that these antenna arrays are suitable for radar application.
S-Visibility Problem In Vlsi Chip Design,
2017
TÜBİTAK
S-Visibility Problem In Vlsi Chip Design, Marzieh Eskandari, Mahdieh Yeganeh
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, a new version of very large scale integration (VLSI) layouts compaction problem is considered. Bar visibility graph (BVG) is a simple geometric model for VLSI chip design and layout problems. In all previous works, vertical bars or other chip components in the plane model gates, as well as edges, are modeled by horizontal visibilities between bars. In this study, for a given set of vertical bars, the edges can be modeled with orthogonal paths known as staircases. Therefore, we consider a new version of bar visibility graphs (BsVG). We then present an algorithm to solve the s-visibility …
Ann-Based Shepwm Using A Harmony Search On A New Multilevel Inverter Topology,
2017
TÜBİTAK
Ann-Based Shepwm Using A Harmony Search On A New Multilevel Inverter Topology, Fayçal Chabni, Rachid Taleb, M'Hamed Helaimi
Turkish Journal of Electrical Engineering and Computer Sciences
This article presents the application of the harmony search (HS) optimization algorithm for selective harmonic elimination PWM (SHEPWM) in a new topology of multilevel inverters with reduced number of electronic switching elements. The main objective of the harmonic elimination strategy is eliminating undesired low-rank harmonics in order to improve the quality of the output waveform. The harmonic elimination strategy is achieved by solving a system of nonlinear equations. In this paper harmony search optimization is applied using artificial neural networks (ANNs) on a new 21-level inverter topology. The algorithm is based on a music improvisation process. MATLAB programming software is …
Visual Data Mining,
2017
Central Washington University
Visual Data Mining, Syeda Sadiya
All Graduate Projects
Occlusion is one of the major problems for interactive visual knowledge discovery and data mining in the process of finding patterns in multidimensional data.This project proposes a hybrid method that combines visual and analytical means to deal with occlusion in visual knowledge discovery called as GLC-S which uses visualization of n-D data in 2D in a set of Shifted Paired Coordinates (SPC). A set of Shifted Paired Coordinates for n-D data consists of n/2 pairs of common Cartesian coordinates that are shifted relative to each other to avoid their overlap. Each n-D point A is represented as a directed graph …
Data Masking, Encryption, And Their Effect On Classification Performance: Trade-Offs Between Data Security And Utility,
2017
Nova Southeastern University
Data Masking, Encryption, And Their Effect On Classification Performance: Trade-Offs Between Data Security And Utility, Juan C. Asenjo
CCAC Theses and Dissertations
As data mining increasingly shapes organizational decision-making, the quality of its results must be questioned to ensure trust in the technology. Inaccuracies can mislead decision-makers and cause costly mistakes. With more data collected for analytical purposes, privacy is also a major concern. Data security policies and regulations are increasingly put in place to manage risks, but these policies and regulations often employ technologies that substitute and/or suppress sensitive details contained in the data sets being mined. Data masking and substitution and/or data encryption and suppression of sensitive attributes from data sets can limit access to important details. It is believed …
