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Articles 2671 - 2700 of 3106
Full-Text Articles in Physical Sciences and Mathematics
Analysis Of Orthogonal Matching Pursuit Based Subsurface Imaging For Compressive Ground Penetrating Radars, Mehmet Ali̇ Çağri Tuncer, Ali̇ Cafer Gürbüz
Analysis Of Orthogonal Matching Pursuit Based Subsurface Imaging For Compressive Ground Penetrating Radars, Mehmet Ali̇ Çağri Tuncer, Ali̇ Cafer Gürbüz
Turkish Journal of Electrical Engineering and Computer Sciences
It is shown that compressive sensing (CS) theory can be used for subsurface imaging in stepped frequency ground penetrating radars (GPR), resulting in robust sparse images, using fewer measurements. Although the data acquisition time is decreased by CS, the computational complexity of the minimization based imaging algorithm is too costly, which makes the algorithm useless, especially for extensive discretization or 3D imaging. In this paper, a greedy alternative, orthogonal matching pursuit (OMP) is used for imaging subsurface and its performance under various conditions is compared to CS imaging method. Results show that OMP could reconstruct sparse signals robustly as well …
A Novel Structure To Enhance Magnetic Force And Velocity In Tubular Linear Reluctance Motor, Ali Mosallanejad, Abbas Shoulaie
A Novel Structure To Enhance Magnetic Force And Velocity In Tubular Linear Reluctance Motor, Ali Mosallanejad, Abbas Shoulaie
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, a novel design for a tubular linear reluctance motor (TLRM) has been developed. This paper presents a novel structure to enhance magnetic force and velocity in a TLRM. The new structure is accomplished through some changes in a TLRM, which results in a step winding structure. Comparing the proposed motor and the typical motor performances, it is proven that the proposed motor has better performance. For dynamic modeling of the proposed TLRM and to obtain the motor output characteristics, the method used for inductance profile calculation is described. The performance improvements in the proposed motor are evaluated …
Application Of The Posicast Control Method To Static Shunt Compensators, Amir Ghorbani, Siamak Masoudi, Arash Shabani
Application Of The Posicast Control Method To Static Shunt Compensators, Amir Ghorbani, Siamak Masoudi, Arash Shabani
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, the Posicast control method is used for decreasing the reactive power oscillations of static shunt compensators. Shunt compensators such as the static synchronous compensator (STATCOM) and static VAR compensator (SVC) are considered to be FACTS devices. The applied control method decreases the amount of oscillations in the outputs of STATCOM and SVC considerably, with fast damping. In this paper, a PI controller is added to the model to decrease the sensitivity of the Posicast controller to the parameter variations and plant model mismatch. Simplicity and applicability are the main features of this controller. The model is simulated …
Optimal Design Of Upfc-Based Damping Controller Using Imperialist Competitive Algorithm, Ali Ajami, Reza Gholizadeh
Optimal Design Of Upfc-Based Damping Controller Using Imperialist Competitive Algorithm, Ali Ajami, Reza Gholizadeh
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, the optimal design of supplementary controller parameters of a unified power flow controller (UPFC) to damp low-frequency oscillations in a weakly connected system is investigated. The individual design of the UPFC controller, using the imperialist competitive algorithm (ICA) technique over a wide range of operating conditions, is discussed. The effectiveness and validity of the proposed controller on damping low-frequency oscillations is tested through a time-domain simulation and eigenvalue analysis under 4 loading conditions and a large disturbance. The simulation results, carried out using MATLAB/Simulink software, reveal that the tuned ICA-based UPFC controller has an excellent capability of …
Broken Rotor Bar Fault Detection In Inverter-Fed Squirrel Cage Induction Motors Using Stator Current Analysis And Fuzzy Logic, Mehmet Akar, İlyas Çankaya
Broken Rotor Bar Fault Detection In Inverter-Fed Squirrel Cage Induction Motors Using Stator Current Analysis And Fuzzy Logic, Mehmet Akar, İlyas Çankaya
Turkish Journal of Electrical Engineering and Computer Sciences
This paper presents the implementation of broken rotor bar fault detection in an inverter-fed induction motor using motor current signal analysis (MCSA) and prognosis with fuzzy logic. Recently, inverter-fed induction motors have become very popular because of their adjustable speed drive. They have been used in many vital control applications such as rolling mills, variable speed compressors, pumps, and fans. The condition monitoring of these motors can significantly reduce the cost of maintenance in the early detection of faults. In this study, MCSA is applied to an inverter-fed induction motor to detect broken rotor bar faults. The diagnosis of a …
Fractional Pid Controllers Tuned By Evolutionary Algorithms For Robot Trajectory Control, Zafer Bi̇ngül, Oğuzhan Karahan
Fractional Pid Controllers Tuned By Evolutionary Algorithms For Robot Trajectory Control, Zafer Bi̇ngül, Oğuzhan Karahan
Turkish Journal of Electrical Engineering and Computer Sciences
The aim of this paper is to compare the performances of a fractional order proportional integral derivative (FOPID) controller tuned with evolutionary algorithms for robot trajectory control. In order to make this comparison, a 2-degrees-of-freedom planar robot was controlled by a FOPID controller tuned with particle swarm optimization (PSO) and a real coded genetic algorithm (GA). In order to see the effects of the cost functions on the optimum parameters of the FOPID controller, 3 different cost functions were used: the root mean squared error (MRSE), mean absolute error (MAE), and mean minimum fuel and absolute error (MMFAE). In order …
Identification Of Linear Dynamic Systems Using The Artificial Bee Colony Algorithm, Özden Erçi̇n, Ramazan Çoban
Identification Of Linear Dynamic Systems Using The Artificial Bee Colony Algorithm, Özden Erçi̇n, Ramazan Çoban
Turkish Journal of Electrical Engineering and Computer Sciences
This paper presents an investigation into the development of system identification using the artificial bee colony (ABC) algorithm. A system identification task can be formulated as an optimization problem where the objective is to obtain a model and a set of parameters that minimize the prediction error between the measured plant outputs and the model outputs. The most common existing system identification approaches, such as the recursive least squares method and autoregressive exogenous method, are substantially analytical and based on a mathematical derivation of the system's model. Evolutionary computation, which seems to be a very promising approach, is an alternative …
Abstract Feature Extraction For Text Classification, Göksel Bi̇ri̇ci̇k, Banu Di̇ri̇, Ahmet Coşkun Sönmez
Abstract Feature Extraction For Text Classification, Göksel Bi̇ri̇ci̇k, Banu Di̇ri̇, Ahmet Coşkun Sönmez
Turkish Journal of Electrical Engineering and Computer Sciences
Feature selection and extraction are frequently used solutions to overcome the curse of dimensionality in text classification problems. We introduce an extraction method that summarizes the features of the document samples, where the new features aggregate information about how much evidence there is in a document, for each class. We project the high dimensional features of documents onto a new feature space having dimensions equal to the number of classes in order to form the abstract features. We test our method on 7 different text classification algorithms, with different classifier design approaches. We examine performances of the classifiers applied on …
Pi And Pid Stabilization Of Neutral And Retarded Systems With Time Delay, Serdar Ethem Hamamci
Pi And Pid Stabilization Of Neutral And Retarded Systems With Time Delay, Serdar Ethem Hamamci
Turkish Journal of Electrical Engineering and Computer Sciences
Stabilization using fixed-order controllers is one of the key topics in control system design for the linear time-invariant (LTI) systems. In this paper, the stabilization of LTI neutral and retarded time-delay systems by means of PI and PID controllers is investigated in detail. The basic theme of the presented approach is to obtain a global stability region in the 2-dimensional (2-D) (k_p, k_i)-plane for the PI controller and in the 3-dimensional (3-D) (k_p, k_i, k_d)-space for the PID controllers. This region is formed by stability boundaries that are defined as the real root boundary, infinite root boundary, and complex root …
An Implementation Of Modified Scatter Search Algorithm To Transmission Expansion Planning, Majid Zeinaddini Maymand, Masoud Rashidinejad, Hamid Khorasani, Mohsen Rahmani, Amin Mahmoudabadi
An Implementation Of Modified Scatter Search Algorithm To Transmission Expansion Planning, Majid Zeinaddini Maymand, Masoud Rashidinejad, Hamid Khorasani, Mohsen Rahmani, Amin Mahmoudabadi
Turkish Journal of Electrical Engineering and Computer Sciences
Transmission network expansion planning (TNEP) is one of the most important tasks in the field of power systems, especially in deregulated power system environments. TNEP is a nonlinear mixed integer programming problem that can be solved via hybrid heuristic algorithms. This paper presents a modified scatter search algorithm (MSSA) to reinforce the ordinary scatter search algorithm (SSA) to be equipped for handling large scale transmission expansion planning (TEP) problems. The proposed methodology is based on the SSA, incorporating some improved strategies so as to decrease the number of linear programming problems required to be solved iteratively. In this study, it …
Dynamic Stability Enhancement Of A Multimachine Electric Power System Using Statcom, Hasan Fayazi Boroujeni, Reza Hemmati, Sayed Mojtaba Shirvani Boroujeni
Dynamic Stability Enhancement Of A Multimachine Electric Power System Using Statcom, Hasan Fayazi Boroujeni, Reza Hemmati, Sayed Mojtaba Shirvani Boroujeni
Turkish Journal of Electrical Engineering and Computer Sciences
With the expansion of electric power systems, the size and complexity of the network is increased. One of the most important drawbacks of network expansion is the reduction in the damping torque of the whole system. The lack of damping torque can lead to fluctuations and instability in the power system. With regard to this problem, power system stabilizers (PSSs) have been widely utilized to improve power system stability. However, due to some drawbacks of the conventional PSSs, the need for finding a better substitution still remains. Therefore, in this paper, the application of a static synchronous compensator (STATCOM) to …
A Neural-Based Electromagnetic Inverse Scattering Approach To The Detection Of A Conducting Cylinder Coated With A Dielectric Material, Senem Makal, Ahmet Kizilay
A Neural-Based Electromagnetic Inverse Scattering Approach To The Detection Of A Conducting Cylinder Coated With A Dielectric Material, Senem Makal, Ahmet Kizilay
Turkish Journal of Electrical Engineering and Computer Sciences
In this study, a radial basis function neural network approach is applied for the estimation of the localization and the radius of a conducting cylinder with a circular cross-section coated with a dielectric material. A set of features, the radar cross-section (RCS) values, are derived from scattered fields, which are calculated using the surface equivalence principle and the method of moment. RCS values are obtained using 10 different scattering angles that are fed into the network. The outputs of the network are the location (x_0, y_0) and the radius (r_p) of the conducting cylinder. This is an application of the …
Resolution Enhancement Of Video Sequences By Using Discrete Wavelet Transform And Illumination Compensation, Sara Izadpanahi, Çağri Özçinar, Gholamreza Anbarjafari, Hasan Demirel
Resolution Enhancement Of Video Sequences By Using Discrete Wavelet Transform And Illumination Compensation, Sara Izadpanahi, Çağri Özçinar, Gholamreza Anbarjafari, Hasan Demirel
Turkish Journal of Electrical Engineering and Computer Sciences
This research paper proposes a new technique for video resolution enhancement that employees an illumination compensation procedure before the registration process. After the illumination compensation process, the respective frames are registered using the Irani and Peleg technique. In parallel, the corresponding frame is decomposed into high-frequency (low-high, high-low, and high-high) and low-frequency (low-low) subbands using discrete wavelet transform (DWT). The high-frequency subbands are superresolved using bicubic interpolation. Afterwards, the interpolated high-frequency subbands and superresolved low-frequency subband obtained by registration are used to construct the high-resolution frame using inverse DWT. The superiority of the proposed resolution enhancement method over well-known video …
Model Selection And Score Normalization For Text-Dependent Single Utterance Speaker Verification, Osman Büyük, Mustafa Levent Arslan
Model Selection And Score Normalization For Text-Dependent Single Utterance Speaker Verification, Osman Büyük, Mustafa Levent Arslan
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, we investigate model selection and channel variability issues on a text-dependent single utterance (TDSU) speaker verification application. Due to the lack of an appropriate database for the task, a multichannel speaker recognition database, which consists of multiple recordings of a single Turkish utterance, is collected. The first set of experiments is devoted to model selection. Phonetic hidden Markov model (HMM)-based, sentence HMM-based, and Gaussian mixture model (GMM)-based methods are compared to find the most appropriate modeling approach for the target application. Based on the experimental results, the HMM-based methods outperform the GMM. The sentence HMM yields the …
Hybrid Feature Selection For Text Classification, Serkan Günal
Hybrid Feature Selection For Text Classification, Serkan Günal
Turkish Journal of Electrical Engineering and Computer Sciences
Feature selection is vital in the field of pattern classification due to accuracy and processing time considerations. The selection of proper features is of greater importance when the initial feature set is considerably large. Text classification is a typical example of this situation, where the size of the initial feature set may reach to hundreds or even thousands. There are numerous research studies in the literature offering different feature selection strategies for text classification, mostly focused on filters. In spite of the extensive number of these studies, there is no significant work investigating the efficacy of a combination of features, …
Using A Game-Based Learning Model As A New Teaching Strategy For Computer Engineering, Kristijan Kuk, Dragica Jovanovic, Dusan Jokanovic, Petar Spalevic, Marko Caric, Stefan Panic
Using A Game-Based Learning Model As A New Teaching Strategy For Computer Engineering, Kristijan Kuk, Dragica Jovanovic, Dusan Jokanovic, Petar Spalevic, Marko Caric, Stefan Panic
Turkish Journal of Electrical Engineering and Computer Sciences
Interactive multimedia simulations and computer game elements can be successfully combined in order to create new advanced educational resources for teaching today's generation of students. Such a learning environment, a game-based learning model (GBLm), has been designed as a research prototype. This paper describes one type of GBLm for computer engineering, which we have used in the subject of computer graphics for the teaching unit Z-buffer algorithm, in order to facilitate the learning process. The implementation of a GBLm for graphical algorithms (GBL4CAl) is presented in detail as a multimedia interactive learning module designed to motivate students by making learning …
On The Degradation Of Ota-C--Based Cmos Low-Power Filter Circuits For Biomedical Instrumentation, Yasi̇n Özçelep, Ayten Kuntman, Hulusi̇ Hakan Kuntman
On The Degradation Of Ota-C--Based Cmos Low-Power Filter Circuits For Biomedical Instrumentation, Yasi̇n Özçelep, Ayten Kuntman, Hulusi̇ Hakan Kuntman
Turkish Journal of Electrical Engineering and Computer Sciences
In this work, we propose a degraded transistor-based circuit degradation simulation method to investigate the degradation effect in complementary metal-oxide semiconductor (CMOS) biomedical devices. The method is demonstrated on an operational transconductance amplifier and capacitor (OTA-C)-based CMOS filter structure. First, we simulate the degradation of the symmetrical CMOS OTA by determining the degraded transistors in the structure. The simulation results are compared with the experimental results of our previous study. First- and second-order low-pass filter degradations are also simulated to demonstrate the accuracy of the proposed method. Finally, the degradation in the electroencephalogram band-pass filter and its effect on the …
Adaptive Optimization Of Edca Parameters For Improved Qos In Multi-Media Applications, Alparslan Çi̇l, Mehmet Akar, Emi̇n Anarim
Adaptive Optimization Of Edca Parameters For Improved Qos In Multi-Media Applications, Alparslan Çi̇l, Mehmet Akar, Emi̇n Anarim
Turkish Journal of Electrical Engineering and Computer Sciences
IEEE 802.11e Enhanced Distributed Channel Access (EDCA) has been incorporated into the standard as an effective medium access mechanism in order to provide the desired QoS for multimedia applications such as VoIP and IPTV. This paper presents an adaptive optimization algorithm in EDCA which strives to provide improved QoS from both delay and throughput perspectives. As a first step towards this goal, a Markov model of the EDCA mechanism has been introduced, which is subsequently used to compute the estimates of throughput and delay. Based on the analytical model that is validated via real-time simulations in OPNET, a new algorithm …
Hybrid Mpi+Upc Parallel Programming Paradigm On An Smp Cluster, Zeki̇ Bozkuş
Hybrid Mpi+Upc Parallel Programming Paradigm On An Smp Cluster, Zeki̇ Bozkuş
Turkish Journal of Electrical Engineering and Computer Sciences
The symmetric multiprocessing (SMP) cluster system, which consists of shared memory nodes with several multicore central processing units connected to a high-speed network to form a distributed memory system, is the most widely available hardware architecture for the high-performance computing community. Today, the Message Passing Interface (MPI) is the most widely used parallel programming paradigm for SMP clusters, in which the MPI provides programming both for an SMP node and among nodes simultaneously. However, Unified Parallel C (UPC) is an emerging alternative that supports the partitioned global address space model that can be again employed within and across the nodes …
Improved Computerized Evaluation Of Abdominal Aortic Aneurysm, Semi̇h Utku, Hulusi̇ Baysal, Reyat Yilmaz, Aytaç Gülcü, Recep Alp Kut, Ahmet Yi̇ği̇t Göktay
Improved Computerized Evaluation Of Abdominal Aortic Aneurysm, Semi̇h Utku, Hulusi̇ Baysal, Reyat Yilmaz, Aytaç Gülcü, Recep Alp Kut, Ahmet Yi̇ği̇t Göktay
Turkish Journal of Electrical Engineering and Computer Sciences
Accurate measurements of arterial anatomy are emerging as the most important determinants of endovascular abdominal aneurysm repair. It is quite difficult to define and measure arterial anatomy features quantitatively due to the complex structure of the aneurysm and insufficient visual feedback. During decision making, to assist operators in diagnosing abdominal aortic aneurysms, a specialized preprocessing Abdominal Aortic Aneurysm Measurement and Evaluation Tool (AMET) was developed. AMET provides visual interfaces with broad measurement capabilities to generate a 3D model of the aorta for a better diagnosis and accurate stent selection. The accuracy and usability of the tool was tested with a …
Optimization Of Pilot Tones Using Differential Evolution Algorithm In Mimo-Ofdm Systems, Muhammet Nuri̇ Seyman, Necmi̇ Taşpinar
Optimization Of Pilot Tones Using Differential Evolution Algorithm In Mimo-Ofdm Systems, Muhammet Nuri̇ Seyman, Necmi̇ Taşpinar
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, we propose a differential evolution (DE) algorithm for optimizing the placement and power of the pilot tones that are utilized by a least square (LS) algorithm for channel estimation in multiple-input and multiple-output orthogonal frequency-division multiplexing (MIMO-OFDM) systems. Computer simulations demonstrated that the performance of the LS algorithm was increased by optimizing the pilot tones with the DE algorithm instead of locating them orthogonally. We used the upper bound of the mean square error (MSE) as a fitness function of the DE algorithm for optimization tasks. With the use of an upper bound, it is not necessary …
A Modified Particle Swarm Optimization Algorithm And Its Application To The Multiobjective Fet Modeling Problem, Ufuk Özkaya, Fi̇li̇z Güneş
A Modified Particle Swarm Optimization Algorithm And Its Application To The Multiobjective Fet Modeling Problem, Ufuk Özkaya, Fi̇li̇z Güneş
Turkish Journal of Electrical Engineering and Computer Sciences
This paper introduces a modified particle swarm algorithm to handle multiobjective optimization problems. In multiobjective PSO algorithms, the determination of Pareto optimal solutions depends directly on the strategy of assigning a best local guide to each particle. In this work, the PSO algorithm is modified to assign a best local guide to each particle by using minimum angular distance information. This algorithm is implemented to determine field-effect transistor (FET) model elements subject to the Pareto domination between the scattering parameters and operation bandwidth. Furthermore, the results are compared with those obtained by the nondominated sorting genetic algorithm-II. FET models are …
Healthface: A Web-Based Remote Monitoring Interface For Medical Healthcare Systems Based On A Wireless Body Area Sensor Network, İsmai̇l Kirbaş, Cüneyt Bayilmiş
Healthface: A Web-Based Remote Monitoring Interface For Medical Healthcare Systems Based On A Wireless Body Area Sensor Network, İsmai̇l Kirbaş, Cüneyt Bayilmiş
Turkish Journal of Electrical Engineering and Computer Sciences
The wireless body area sensor network (WBASN) is a type of wireless sensor network. The wireless sensor nodes in a WBASN are placed on, near, or within a human body. In a medical healthcare system, WBASNs continuously provide healthcare monitoring, especially of elderly or ill people, wherever the patient goes. Wireless nodes sense and process human vital signs such as heart rate, blood pressure, body temperature, and respiration. They then send collected data to a medical center via a base station in order for medical professionals to monitor the patient's health. In the medical center, doctors and caregivers need monitoring …
Analysis, Nonlinear Control, And Chaos Generator Circuit Of Another Strange Chaotic System, İhsan Pehli̇van, Zhouchao Wei
Analysis, Nonlinear Control, And Chaos Generator Circuit Of Another Strange Chaotic System, İhsan Pehli̇van, Zhouchao Wei
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, we introduce a new 3-dimensional quadratic continuous autonomous chaotic system. This system can generate strange and interesting attractors. Some basic dynamical properties, such as bifurcations, and chaotic behaviors of the new chaotic system are investigated analytically and numerically. We propose a nonlinear control scheme to discuss codimension 1 and 2 Hopf bifurcations. In addition, a new circuit implementation of the chaotic attractor is reported and examined in PSpice. The new system is suitable for purposefully generating chaos in chaos-based engineering applications.
Considering Transmission Loss For An Economic Dispatch Problem Without Valve-Point Loading Using An Ep-Epso Algorithm, Sevugarathinam Muthu Vijaya Pandian, Keppanagowder Thanushkodi
Considering Transmission Loss For An Economic Dispatch Problem Without Valve-Point Loading Using An Ep-Epso Algorithm, Sevugarathinam Muthu Vijaya Pandian, Keppanagowder Thanushkodi
Turkish Journal of Electrical Engineering and Computer Sciences
Economic dispatch (ED) is one of the most important optimization problems in a power system. The objective of ED is sharing the power demand among the online generators while keeping the minimum cost of generation as a constraint. The aim of this paper is to operate an electric power system as economically as possible within its security limits. This paper proposes the following 2 new particle swarm optimization (PSO) algorithms to solve a nonconvex economic dispatch problem: an efficient PSO is termed as efficient particle swarm optimization (EPSO), and a hybrid of evolutionary programming (EP) and EPSO is termed as …
Symbolic Regression Of Crop Pest Forecasting Using Genetic Programming, Basim Alhadidi, Alaa Alafeef, Heba Al-Hiari
Symbolic Regression Of Crop Pest Forecasting Using Genetic Programming, Basim Alhadidi, Alaa Alafeef, Heba Al-Hiari
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, we propose and evaluate a mathematical model that describes the reported data on crop pests to get an accurate prediction of production costs, food safety, and the protection of the environment. Meteorological factors are not the only things that affect a bumper harvest; it is also affected by crop plant diseases and insect pests. Studies show that relying solely on the naked-eye observations of experts to forecast well-planned agriculture is not always sufficient to achieve effective control. Providing fast, automatic, cheap, and accurate artificial intelligence-based solutions for that task can be of great realistic significance. The proposed …
Three-Dimensional Numerical Simulation Of Crystal And Crucible Rotations During Czochralski Growth Of Ge_Xsi_{1-X} Single Crystals, Serkan Abbasoğlu
Three-Dimensional Numerical Simulation Of Crystal And Crucible Rotations During Czochralski Growth Of Ge_Xsi_{1-X} Single Crystals, Serkan Abbasoğlu
Turkish Journal of Electrical Engineering and Computer Sciences
The influence of crystal and crucible rotations on the flow field and the radial segregation of silicon are predicted during the growth of Ge_xSi_{1-x} crystals by the Czochralski method under microgravity conditions. Time-dependent 3-dimensional numerical simulations are carried out to present the influence of several rotation rates on the radial segregation and flow fields during the growth of Ge_xSi_{1-x}. Thermal and solutal Marangoni convection are also considered during this study. Different crystal rotation rates varying between 0 and 30 rpm and stationary or -2 rpm crucible rotation rates are considered. The results show that the crystal and crucible rotation rates …
Ttradeoff Tables For Compression Functions: How To Invert Hash Values Radeoff Tables For Compression Functions: How To Invert Hash Values, Orhun Kara, Adem Atalay
Ttradeoff Tables For Compression Functions: How To Invert Hash Values Radeoff Tables For Compression Functions: How To Invert Hash Values, Orhun Kara, Adem Atalay
Turkish Journal of Electrical Engineering and Computer Sciences
Hash functions are one of the ubiquitous cryptographic functions used widely for various applications such as digital signatures, data integrity, authentication protocols, MAC algorithms, RNGs, etc. Hash functions are supposed to be one-way, i.e., preimage resistant. One interesting property of hash functions is that they process arbitrary-length messages into fixed-length outputs. In general, this can be achieved mostly by applying compression functions onto the message blocks of fixed length, recursively. The length of the message is incorporated as padding in the last block prior to the hash, a procedure called the Merkle-Damgard strengthening. In this paper, we introduce a new …
A Robust Adaptive Fuzzy Control Of A Unified Power Flow Controller, Sebaa Morsli, Allaoui Tayeb, Denai Mouloud, Chaker Abdelkader
A Robust Adaptive Fuzzy Control Of A Unified Power Flow Controller, Sebaa Morsli, Allaoui Tayeb, Denai Mouloud, Chaker Abdelkader
Turkish Journal of Electrical Engineering and Computer Sciences
This paper investigates the control of a unified power flow controller (UPFC) to improve the stability of a power system, hence providing security under increased power flow conditions. The proposed control methods include a direct proportional and integral (PI) controller and an adaptive fuzzy logic controller (AFLC). The performances of these controllers were evaluated under different operating conditions of the power system and the results demonstrated that PI and AFLC are very effective in improving the transient power system stability and very robust against variable transmission line parameters.
Mathematical Modeling And Vertical Flight Control Of A Tilt-Wing Uav, Kaan Taha Öner, Ertuğrul Çeti̇nsoy, Efe Sirimoğlu, Cevdet Hançer, Mustafa Ünel, Mahmut Faruk Akşi̇t, Kayhan Gülez, İlyas Kandemi̇r
Mathematical Modeling And Vertical Flight Control Of A Tilt-Wing Uav, Kaan Taha Öner, Ertuğrul Çeti̇nsoy, Efe Sirimoğlu, Cevdet Hançer, Mustafa Ünel, Mahmut Faruk Akşi̇t, Kayhan Gülez, İlyas Kandemi̇r
Turkish Journal of Electrical Engineering and Computer Sciences
This paper presents a mathematical model and vertical flight control algorithms for a new tilt-wing unmanned aerial vehicle (UAV). The vehicle is capable of vertical take-off and landing (VTOL). Due to its tilt-wing structure, it can also fly horizontally. The mathematical model of the vehicle is obtained using Newton-Euler formulation. A gravity compensated PID controller is designed for altitude control, and three PID controllers are designed for attitude stabilization of the vehicle. Performances of these controllers are found to be quite satisfactory as demonstrated by indoor and outdoor flight experiments.