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- Classification (66)
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Articles 2251 - 2280 of 3020
Full-Text Articles in Physical Sciences and Mathematics
Real-Time Control Of An Automated Guided Vehicle Using A Continuous Mode Of Sliding Mode Control, Bi̇rol Soysal
Real-Time Control Of An Automated Guided Vehicle Using A Continuous Mode Of Sliding Mode Control, Bi̇rol Soysal
Turkish Journal of Electrical Engineering and Computer Sciences
This paper proposes a tracking control method for a certain type of differential-drive wheeled mobile robot, called automated guided vehicles (AGVs), using a continuous mode approach of sliding mode control (SMC). The SMC applied produces a continuous signal in between the U and -U control signals instead of discrete ones. The controller is applied to control the velocity and direction angle of the vehicle in order to keep it on a desired path. The obtained algorithm is applied to the experimental system under load and disturbance to show its robustness. The experimental results are satisfactory and verify the performance of …
Solving A New Bi-Objective Joint Replenishment Inventory Model With Modified Rand And Genetic Algorithms, Ommolbanin Yousefi, Seyed Jafar Sadjadi
Solving A New Bi-Objective Joint Replenishment Inventory Model With Modified Rand And Genetic Algorithms, Ommolbanin Yousefi, Seyed Jafar Sadjadi
Turkish Journal of Electrical Engineering and Computer Sciences
There are many cases in real inventory systems where more than one objective must be optimized. The main purpose of this research is to develop a multiobjective joint replenishment problem (JRP), where one objective is the minimization of the total inventory investment and another is the minimization of the total inventory ordering and holding costs. To solve the suggested model, 3 algorithms are proposed. In the first algorithm, the existing RAND method, called the best heuristic for solving the JRP, is modified and a new heuristic algorithm is developed to be applicable to the JRP with 2 objectives. The second …
New Design Of Intelligent Load Shedding Algorithm Based On Critical Line Overloads To Reduce Network Cascading Failure Risks, Mehrdad Majidi, Mohammad-Reza Aghamohammadi, Moein Manbachi
New Design Of Intelligent Load Shedding Algorithm Based On Critical Line Overloads To Reduce Network Cascading Failure Risks, Mehrdad Majidi, Mohammad-Reza Aghamohammadi, Moein Manbachi
Turkish Journal of Electrical Engineering and Computer Sciences
This paper presents a new algorithm for intelligent load shedding based on critical line overloads. This method can increase the efficiency for determining critical lines and sensitive loads. Hence, when critical lines expose an overload, the system will run an intelligent load shedding, which considerably curtails the sensitive loads of critical transmission lines. This can fully reduce the harmful risks of power system cascading failures that impose extensive losses to the economy of a country. For testing the accuracy and applicability of this technique, the IEEE 39-bus test system is applied as a standard case study.
Face Recognition Across Pose Variation And The 3s Problem, Jamal Hussain Shah, Muhammad Sharif, Mudassar Raza, Aisha Azeem
Face Recognition Across Pose Variation And The 3s Problem, Jamal Hussain Shah, Muhammad Sharif, Mudassar Raza, Aisha Azeem
Turkish Journal of Electrical Engineering and Computer Sciences
Most face recognition methods are based on linear and nonlinear subspace features extraction and classification tasks. These classification methods are used for global and local facial features for person identification. Both local and global features play different roles for recognition and classification. There are a number of face recognition methods that have been proposed up until now, and they produce good results. However, when small sample size (3S) and pose variation problems are taken into consideration, face recognition becomes more complex and does not produce good results. In this paper, 3S and pose variation problems are dealt with. First, linear …
The Design Of An Embedded Spinal Cord Stimulator, Fi̇kret Yalçinkaya, Ali̇ Erbaş
The Design Of An Embedded Spinal Cord Stimulator, Fi̇kret Yalçinkaya, Ali̇ Erbaş
Turkish Journal of Electrical Engineering and Computer Sciences
Spinal cord stimulation is a physical therapy methodology utilizing electrical impulses, pulses, or a combination of various standard electrical waveforms to block pain. However, standard forms are not functioning effectively for each illness due to the unique conditions of the patient. Therefore, patient-specific waveforms (or user-defined waveforms) integrated with nondestructive, complete, or partially noninvasive and effective medical instruments to help relieve pain are required. In the literature, 2 different designs have been discussed: the bedside/portable and the implantable/surgical types. This work is introducing a new hybrid type: a portable touch-screen multichannel embedded spinal cord stimulator. This work is made of …
Multiuser Detection Using Soft Particle Swarm Optimization Along With Radial Basis Function, Muhammad Zubair, Muhammad Aamer Saleem Choudhry, Ijaz Mansoor Qureshi
Multiuser Detection Using Soft Particle Swarm Optimization Along With Radial Basis Function, Muhammad Zubair, Muhammad Aamer Saleem Choudhry, Ijaz Mansoor Qureshi
Turkish Journal of Electrical Engineering and Computer Sciences
The multiuser detection (MUD) problem was addressed as a pattern classification problem. Due to their strength in solving nonlinear separable problems, radial basis functions, aided by soft particle swarm optimization, were proposed to perform MUD for a synchronous direct sequence code division multiple access system. The proposed solution was shown to exhibit performance better than a number of other suboptimum detectors including the genetic algorithm and the classical particle swarm optimization algorithm.
Online Feature Selection And Classification With Incomplete Data, Habi̇l Kalkan
Online Feature Selection And Classification With Incomplete Data, Habi̇l Kalkan
Turkish Journal of Electrical Engineering and Computer Sciences
This paper presents a classification system in which learning, feature selection, and classification for incomplete data are simultaneously carried out in an online manner. Learning is conducted on a predefined model including the class-dependent mean vectors and correlation coefficients, which are obtained by incrementally processing the incoming observations with missing features. A nearest neighbor with a Gaussian mixture model, whose parameters are also estimated from the trained model, is used for classification. When a testing observation is received, the algorithm discards the missing attributes on the observation and ranks the available features by performing feature selection on the model that …
Effects Of A Current Transformer's Magnetizing Current On The Driving Voltage In Self-Oscillating Converters, Güngör Bal, Seli̇m Öncü
Effects Of A Current Transformer's Magnetizing Current On The Driving Voltage In Self-Oscillating Converters, Güngör Bal, Seli̇m Öncü
Turkish Journal of Electrical Engineering and Computer Sciences
Magnetizing inductance is one of the parameters that affect the phase and amplitude error of the output current of current transformers (CTs). In this study, the linear circuit model of a CT is developed to be used for driving purposes in power electronics applications. A simulation of the CT and its linear model is achieved. In the model circuit, the effect of the magnetizing inductance on the driving voltage can be examined. The equivalent circuit simulation results and the linear model simulation results along with the calculated results show agreement with each other. These results are compared with experimental results.
Passive Ac Network Supplying The Integration Of Ccc-Hvdc And Vsc-Hvdc Systems, Ali Bidadfar, Mehrdad Abedi, Mehdi Karrari, Gevorg .Babamalek Gharehpetian, Sanaz Namayan Tavana
Passive Ac Network Supplying The Integration Of Ccc-Hvdc And Vsc-Hvdc Systems, Ali Bidadfar, Mehrdad Abedi, Mehdi Karrari, Gevorg .Babamalek Gharehpetian, Sanaz Namayan Tavana
Turkish Journal of Electrical Engineering and Computer Sciences
The integration of a capacitor-commutated converter (CCC) high-voltage direct current (HVDC) (CCC-HVDC) and voltage source converter (VSC) HVDC (VSC-HVDC) is proposed in this paper to supply entirely passive AC networks. The key point of this integration is the flat characteristic of the DC voltage of the CCC-HVDC, which provides the condition for the VSC to connect to the CCC DC link via a current regulator. The advantages of the proposed combined infeeding system are the requirement of only one DC line, and better dynamic responses. The structure of the proposed infeeding system, as well as its control system, is studied. …
Design, Optimization, And Realization Of A Wire Antenna With A 25:1 Bandwidth Ratio For Terrestrial Communications, Korkut Yeği̇n
Design, Optimization, And Realization Of A Wire Antenna With A 25:1 Bandwidth Ratio For Terrestrial Communications, Korkut Yeği̇n
Turkish Journal of Electrical Engineering and Computer Sciences
Wire antennas can be made wideband if the antenna is loaded with passive elements and connected to a lossless matching network. However, realization of the load component values and matching network can easily become impractical. In this study, using only a surface mount and standard component values, antenna loads and a matching network are optimized using genetic algorithms. The optimized design achieves a 25:1 bandwidth ratio, from 20 MHz to 500 MHz, with a maximum voltage standing wave ratio (VSWR) of 3.5 and minimum system gain of --5 dBi. The antenna system gain at azimuth is taken as the objective …
Stability Analysis Of Multimachine Thermal Power Systems Using The Nature-Inspired Modified Cuckoo Search Algorithm, Shivakumar Rangasamy, Panneerselvam Manickam
Stability Analysis Of Multimachine Thermal Power Systems Using The Nature-Inspired Modified Cuckoo Search Algorithm, Shivakumar Rangasamy, Panneerselvam Manickam
Turkish Journal of Electrical Engineering and Computer Sciences
The stability of modern interconnected thermal power systems is greatly affected by the presence of low-frequency inertial oscillations in the system, due to various forms of disturbances experienced. This paper provides an efficient damping solution to these oscillations based on nature-inspired modified cuckoo search algorithm-based controller design. The proposed controller design is formulated as a parameter optimization problem based on damping ratio and time-domain error deviations. The effectiveness of the proposed damping controller design is illustrated by performing the nonlinear time domain simulations of the test multimachine power systems under various operating conditions and disturbances. Moreover, an exhaustive comparative stability …
Reliability-Based Maintenance Scheduling Of Generating Units In Restructured Power Systems, Mahmud Fotuhi Firuzabad, Farrokh Aminifar, Abbas Shahzadeh
Reliability-Based Maintenance Scheduling Of Generating Units In Restructured Power Systems, Mahmud Fotuhi Firuzabad, Farrokh Aminifar, Abbas Shahzadeh
Turkish Journal of Electrical Engineering and Computer Sciences
Maintenance scheduling of generating units in restructured power systems is a collaborative and interactive process between independent system operators (ISOs) and generating companies (GENCOs). The ISO should comply with GENCO maintenance preferences subject to targeted system reliability levels. This process might be multistage since the admission of all initial unit outage requests may threaten system reliability. Hence, the ISO accepts some proposals and determines alternatives for the remaining units. The GENCOs are then allowed to confirm the alternatives or revise them. In this paper the ISO problem of generating unit maintenance scheduling is tackled. The objective function is to minimize …
Optimal Reactive Power Flow Solution In Multiterminal Ac-Dc Systems Based On Artificial Bee Colony Algorithm, Faruk Yalçin, Uğur Ari̇foğlu
Optimal Reactive Power Flow Solution In Multiterminal Ac-Dc Systems Based On Artificial Bee Colony Algorithm, Faruk Yalçin, Uğur Ari̇foğlu
Turkish Journal of Electrical Engineering and Computer Sciences
Active power loss optimization is one of the important goals in electrical power systems and it is provided by optimal reactive power flow (ORPF). In this study, a new approach for the solution of the ORPF in multiterminal AC-DC systems is proposed. This approach provides 3 main contributions. First, the convergence problem in the AC-DC power flow is solved. Second, the problem of getting stuck in local minima during the optimization process is overcome. Third, a better global optimum point is obtained for the ORPF. Active power loss optimization is implemented through the artificial bee colony (ABC) algorithm, which is …
Comparison Of Ais And Fuzzy C-Means Clustering Methods On The Classification Of Breast Cancer And Diabetes Datasets, Seral Özşen, Rahi̇me Ceylan
Comparison Of Ais And Fuzzy C-Means Clustering Methods On The Classification Of Breast Cancer And Diabetes Datasets, Seral Özşen, Rahi̇me Ceylan
Turkish Journal of Electrical Engineering and Computer Sciences
Data reduction is an indispensable part of pattern classification processes in many cases. If the number of samples is excessive, sample reduction or data reduction algorithms can be used for an effective processing time and reliable successive results. Many methods have been used for data reduction. Fuzzy c-means is one of these methods and it is widely used in such applications as clustering algorithms. In this study, we applied a different clustering algorithm, an artificial immune system (AIS), for the data reduction process. We realized the performance evaluation experiments on the standard Chainlink and Iris datasets, while the main application …
A Performance Comparison Of Linear And Nonlinear Control Of A Scig-Wind Farm Connecting To A Distribution Network, Mohamed Benchagra, Mohamed Maaroufi, Mohammed Ouassaid
A Performance Comparison Of Linear And Nonlinear Control Of A Scig-Wind Farm Connecting To A Distribution Network, Mohamed Benchagra, Mohamed Maaroufi, Mohammed Ouassaid
Turkish Journal of Electrical Engineering and Computer Sciences
This study presents a comparison of linear and nonlinear control to regulate the DC-link voltage and power factor correction of a wind farm equipped with squirrel cage induction generators (SCIGs), connecting to a 22-kV distribution network. Both active and reactive powers are employed in 2 independent control laws. The proposed control strategies are derived from the Lyapunov approach. The aim of the control is to maximize the generated power with the lowest possible impact in the grid voltage and frequency during normal operation and under the occurrence of faults. The nonlinear backstepping controller to be used for the control of …
Coherence Analysis On Thermal Effect For Power Cables Under Different Environmental Conditions, Sezai̇ Taşkin, Şahi̇n Serhat Şeker, Özcan Kalenderli̇, Murat Karahan
Coherence Analysis On Thermal Effect For Power Cables Under Different Environmental Conditions, Sezai̇ Taşkin, Şahi̇n Serhat Şeker, Özcan Kalenderli̇, Murat Karahan
Turkish Journal of Electrical Engineering and Computer Sciences
There are 2 important aspects of this research; these are the experimental study and the data analysis, which are based on coherence analysis. In this study, a low-voltage power cable is tested under 2 different environments, air and water, and the variations in temperature are measured for the conductor, the sheath parts of the cable, and the environment. The recorded test data are analyzed using such as coherence analysis. This in turn provides the means to determine the relationship among the sheath, conductor, and the environment. In conclusion, high correlated peaks in the frequency domain are used to determine the …
Modeling And Simulation Of Deadbeat-Based Pi Controller In A Single-Phase H-Bridge Inverter For Stand-Alone Applications, Tow Leong Tiang, Dahaman Ishak
Modeling And Simulation Of Deadbeat-Based Pi Controller In A Single-Phase H-Bridge Inverter For Stand-Alone Applications, Tow Leong Tiang, Dahaman Ishak
Turkish Journal of Electrical Engineering and Computer Sciences
This paper presents a deadbeat-based proportional-integral (PI) controller for a stand-alone single-phase voltage source inverter using a battery cell as the primary energy source. The inverter system is simulated in MATLAB/Simulink. It consists of a lead acid battery, third-order Butterworth low-pass DC filter and AC filter, H-bridge inverter, step-up transformer, and a variety of loads, as well as its sinusoidal pulse-width modulation (SPWM) deadbeat-based PI controller. In this paper, 2 simulation case studies are carried out, which are the abrupt load changes from a 400 W resistive load to a 500 W resistive load, and from a 400 W resistive …
Optimal Fuzzy Load Frequency Controller With Simultaneous Auto-Tuned Membership Functions And Fuzzy Control Rules, Abas Ali Zamani, Ehsan Bijami, Farid Sheikholeslam, Bahram Jafrasteh
Optimal Fuzzy Load Frequency Controller With Simultaneous Auto-Tuned Membership Functions And Fuzzy Control Rules, Abas Ali Zamani, Ehsan Bijami, Farid Sheikholeslam, Bahram Jafrasteh
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, an auto-tuned fuzzy load frequency controller (FLFC)-based artificial bee colony (ABC) algorithm is developed to quench the deviations in the frequency and tie-line power due to load disturbances in an interconnected power system. Optimal tuning of membership functions (MFs) and fuzzy control rules is very important to improve the design performance and achieve a satisfactory level of robustness for a particular operation. In this work, to reduce the fuzzy system design effort and take large parametric uncertainties into account, a new systematic and simultaneous tuning method is developed for designing MFs and fuzzy rules. For this, the …
Adaptive Feedback Control For Linear Singular Systems, Azita Azarfar, Heydar Toossian Shandiz, Masoud Shafiee
Adaptive Feedback Control For Linear Singular Systems, Azita Azarfar, Heydar Toossian Shandiz, Masoud Shafiee
Turkish Journal of Electrical Engineering and Computer Sciences
An adaptive state feedback control approach for linear descriptor (or singular) systems is investigated in this paper, which makes the closed-loop dynamics of this class of systems regular, impulse-free, and stable. The proposed adaptive method is based on the Lyapunov theorem to ensure the admissibility of the descriptor system and it also provides the state tracking with the desired reference trajectory. First, a control law is generated to stabilize the equilibrium point of origin, and, after that, the method is extended to a state tracking controller. The presented controller not only gets the stable output tracking asymptotically but is also …
Increasing Key Space At Little Extra Cost In Rfid Authentications, Gökhan Dalkiliç, Mehmet Hi̇lal Özcanhan, Hafi̇ze Şen Çakir
Increasing Key Space At Little Extra Cost In Rfid Authentications, Gökhan Dalkiliç, Mehmet Hi̇lal Özcanhan, Hafi̇ze Şen Çakir
Turkish Journal of Electrical Engineering and Computer Sciences
Traditional authentication and key establishment protocols utilize nonce parameters as a means for message freshness, recent aliveness, and key derivation. Improving identity verification, increasing key space, or making secret updates more complex through nonces are not goals. Generating random numbers as nonces and not making the most out of them can be considered as a loss in resource stricken radio frequency identification (RFID) tags. By increasing the shared secrets slightly, a new functionality for the nonces is introduced, which makes the authentication and key establishment protocols of RFID systems more secure, in general. The proposed method contributes to the security …
A Web Laboratory Using Matlab Builder Ne For Computer Image Processing, Sezgi̇n Kaçar, Cüneyt Bayilmiş, Özdemi̇r Çeti̇n
A Web Laboratory Using Matlab Builder Ne For Computer Image Processing, Sezgi̇n Kaçar, Cüneyt Bayilmiş, Özdemi̇r Çeti̇n
Turkish Journal of Electrical Engineering and Computer Sciences
Many various instruments are needed for computer image processing. These instruments are used for image restoration, analysis, etc. This paper presents a novel web laboratory based on MATLAB Builder NE with Web Figure, called ImageWeb, to facilitate computer image processing without needed technical information for users. The developed ImageWeb provides fundamental principles of image processing, including basic, compression, edge detection, filtering, optimization, and histogram processes, and so on. In addition, the usage of MATLAB Builder NE with MATLAB Web Figure provides high flexibility with visualization means such as zoom, rotate, and 3-dimensional view. Users can easily access ImageWeb using only …
A New Approach In The Evaluation Of Hospital Information Systems, Güney Gürsel, Neşe Zayi̇m, Kemal Hakan Gülkesen, Ali̇ Ari̇foğlu, Osman Saka
A New Approach In The Evaluation Of Hospital Information Systems, Güney Gürsel, Neşe Zayi̇m, Kemal Hakan Gülkesen, Ali̇ Ari̇foğlu, Osman Saka
Turkish Journal of Electrical Engineering and Computer Sciences
Hospital information system (HIS) evaluation frameworks have largely been discussed in the literature. However, existing frameworks lack one important aspect: to what extent user expectations of HISs are met. In this study, user expectation data are collected by means of the 'expectation questionnaire'. The internal consistencies of the answers to the questionnaire are measured by Cronbach's alpha coefficient. Fuzzy logic methodologies are used to evaluate the expectation variables in the proposed evaluation framework. The evaluation variables are not represented in the results equally; they are reflected by the weights assigned by the users. Our proposed framework provides the overall degree …
Spatiotemporal Realization Of An Artificial Retina Model And Performance Evaluation Through Isi- And Spike Count-Based Image Reconstruction Methods, İrfan Karagöz, Mustafa Özden
Spatiotemporal Realization Of An Artificial Retina Model And Performance Evaluation Through Isi- And Spike Count-Based Image Reconstruction Methods, İrfan Karagöz, Mustafa Özden
Turkish Journal of Electrical Engineering and Computer Sciences
Development of an artificial retina model that can mimic the biologic retina is a highly challenging task and this task is an important step in the development of a visual prosthesis. The receptive field structure of the retina layer is usually modeled as a 2D difference of Gaussian (DOG) filter profile. In the present study, as a different approach, a retina model including a 3D 2-stage DOG filter (3D-ADOG) that has an adaptively changing bandwidth with respect to the local image statistic is developed. Using this modeling, the adaptive image processing of the retina can be realized. The contribution of …
Markovian Approach Applied To Reliability Modeling Of A Wind Farm, Mazaher Hajibashi, Akbar Ebrahimi
Markovian Approach Applied To Reliability Modeling Of A Wind Farm, Mazaher Hajibashi, Akbar Ebrahimi
Turkish Journal of Electrical Engineering and Computer Sciences
The exploitation of wind energy as a resource for generating electricity is going to make a leap forward. Large-scale wind farms (WFs) will be engaged with power systems in the near future and this will cause changes in the supply pattern. Wind speed has an intermittent behavior and the output power of a WF is highly variable, consistent with this fact. The Markov process could consider this characteristic of wind speed using the state transition rate probability matrix, an issue that is neglected when a probability distribution function is established to model the wind speed data. The adequacy indices of …
Current-Mode Universal Filter And Quadrature Oscillator Using Cdtas, Jie Jin, Chunhua Wang
Current-Mode Universal Filter And Quadrature Oscillator Using Cdtas, Jie Jin, Chunhua Wang
Turkish Journal of Electrical Engineering and Computer Sciences
A current differencing transconductance amplifier (CDTA)-based multiple-input single-output (MISO) current-mode universal filter and a quadrature oscillator (QO) are presented in this paper. The same circuit is used in the filter and oscillator, which only consists of 2 CDTAs and 2 capacitors. The universal filter can realize low-pass, high-pass, band-pass, band-stop, and all-pass biquad filter functions. With a slight modification of the filter, a new current-mode QO can be obtained easily. The natural frequency and quality factor of the filter and the conditions of oscillation and frequency of oscillation of the QO are all orthogonally adjustable through the bias currents of …
Vessel Segmentation In Mri Using A Variational Image Subtraction Approach, Ayşe Nurdan Saran, Fati̇h Nar, Murat Saran
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 …
Applications Of Wavelets And Neural Networks For Classification Of Power System Dynamics Events, Samir Avdakovic, Amir Nuhanovic, Mirza Kusljugic, Elvisa Becirovic
Applications Of Wavelets And Neural Networks For Classification Of Power System Dynamics Events, Samir Avdakovic, Amir Nuhanovic, Mirza Kusljugic, Elvisa Becirovic
Turkish Journal of Electrical Engineering and Computer Sciences
This paper investigates the possibility of classifying power system dynamics events using discrete wavelet transform (DWT) and a neural network (NN) by analyzing one variable at a single network bus. Following a disturbance in the power system, it will propagate through the system in the form of low-frequency electromechanical oscillations (LFEOs) in a frequency range of up to 5 Hz. DWT allows the identification of components of the LFEO, their frequencies, and magnitudes. After determining the energy components' share of the analyzed signal using DWT and Parseval's theorem, the input data for the classification process using a NN are obtained. …
How Do Hccmes Perform In Small Samples?, Mehmet Orhan, Esra Şi̇mşek
How Do Hccmes Perform In Small Samples?, Mehmet Orhan, Esra Şi̇mşek
Turkish Journal of Electrical Engineering and Computer Sciences
The purpose of this paper is to explore the performances of prominent and popular heteroscedasticity-consistent covariance matrix estimators (HCCMEs) in small samples. The HCCMEs are selected from the literature and their ability to estimate the true covariance matrix of the coefficient's vector is evaluated through simulation runs. We calculate the percentage difference between the expected value of the HCCME and the true covariance matrix to set a convenient stage to make the comparisons under several different regression settings. The main contribution of the paper is the inclusion of the HCCMEs that have been introduced into the literature recently. We report …
Performance Evaluation Of A Fuzzy Variable Structure Satellite Attitude Controller Under Sensor Data Delay, Bi̇lgehan Erkal, Hüseyi̇n Demi̇rel
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), …
An Efficient Approach To The Local Optimization Of Finite Electromagnetic Band-Gap Structures, David Duque, Vito Lancellotti, Bastiaan Pieter De Hon, Antonius Tijhuis
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 …