Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
- Discipline
- Keyword
-
- Turkey (105)
- 1 (99)
- 2 (82)
- Classification (70)
- Optimization (65)
-
- Deep learning (61)
- Genetic algorithm (61)
- Machine learning (61)
- Synthesis (61)
- Adsorption (53)
- Particle swarm optimization (51)
- Antimicrobial activity (47)
- Geochemistry (47)
- 3 (44)
- Stability (39)
- Artificial neural network (37)
- Phthalocyanine (35)
- Support vector machine (34)
- Feature extraction (32)
- Wireless sensor networks (31)
- Antibacterial activity (29)
- Artificial neural networks (28)
- Feature selection (28)
- Copper (27)
- Cytotoxicity (27)
- Power quality (27)
- Fuzzy logic (26)
- Molecular docking (26)
- Palladium (26)
- Preconcentration (26)
- Publication Year
Articles 6181 - 6210 of 10319
Full-Text Articles in Physical Sciences and Mathematics
A Novel Fuzzy Filter For Speckle Noise Removal, Mehmet Ali̇ Soytürk, Alper Baştürk, Mehmet Emi̇n Yüksel
A Novel Fuzzy Filter For Speckle Noise Removal, Mehmet Ali̇ Soytürk, Alper Baştürk, Mehmet Emi̇n Yüksel
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, a novel fuzzy system-based method for speckle noise removal is proposed. The proposed method consists of a fuzzy inference system, an edge detection and dilation unit, and an image combiner. The fuzzy inference system includes 5 inputs and 1 output, and it is responsible for filtering the speckle noisy image. The inputs of the fuzzy system consist of the center pixel of the filtering window and its 2 horizontal and vertical neighbors. The edge detection and dilation unit is used for classifying the uniform areas and nonuniform image regions such as edges. The image combiner unites the …
Performance Of Exhaustive Search With Parallel Agents, Toni Draganov Stojanovski
Performance Of Exhaustive Search With Parallel Agents, Toni Draganov Stojanovski
Turkish Journal of Electrical Engineering and Computer Sciences
The advent of high-performance computing via many-core processors and distributed processing emphasizes the possibility for exhaustive search by multiple search agents. Despite the occurrence of elegant algorithms for solving complex problems, exhaustive search has retained its significance since many real-life problems exhibit no regular structure and exhaustive search is the only possible solution. Here we analyze the performance of exhaustive search when it is conducted by multiple search agents. Several strategies for joint search with parallel agents are evaluated. We discover that the performance of the search improves with the increase in the level of mutual help between agents. The …
Implementation Of Neural Network-Based Maximum Power Tracking Control For Wind Turbine Generators, Abdulhaki̇m Karakaya, Ercüment Karakaş
Implementation Of Neural Network-Based Maximum Power Tracking Control For Wind Turbine Generators, Abdulhaki̇m Karakaya, Ercüment Karakaş
Turkish Journal of Electrical Engineering and Computer Sciences
In this study, the maximum power point tracking (MPPT) of a permanent magnet synchronous generator used in a wind generator system is realized by a prototype installed in a laboratory environment. The installed prototype is modeled in a MATLAB/Simulink environment. The MPPT is realized by an artificial neural network (ANN). The obtained simulation and experimental results are compared. The maximum power estimation at various windmill speeds (rpm) of the trained ANN in determined reference speeds is analyzed. The zero crossing points of the phases are determined by a digital signal peripheral interface controller and the system is operated according to …
Fault Tolerant Broadcasting Analysis In Wireless Monitoring Networks, Akbar Ghaffarpour Rahbar
Fault Tolerant Broadcasting Analysis In Wireless Monitoring Networks, Akbar Ghaffarpour Rahbar
Turkish Journal of Electrical Engineering and Computer Sciences
Wireless monitoring networks can be used for security applications such as the monitoring of narrow passages and operational fields. These networks can be designed based on sensor networks. In sensor networks, each node can hear a message and broadcast the message to its neighbor nodes. Nevertheless, nodes may fail, so that faulty nodes cannot hear or cannot transmit any message, where the locations of the faulty nodes are unknown and their failures are permanent. In this paper, the nodes are situated on a line or a square grid-based topology in a plane for security/monitoring applications. For each topology, 2 nonadaptive …
A Comparison Of Fuzzy Logic And Pid Controllers To Control Transmitted Power Using A Tcsc, Mohsen Hosseinzadeh Soreshjani, Navid Reza Abjadi, Abbas Kargar, Gholamreza Arab Markadeh
A Comparison Of Fuzzy Logic And Pid Controllers To Control Transmitted Power Using A Tcsc, Mohsen Hosseinzadeh Soreshjani, Navid Reza Abjadi, Abbas Kargar, Gholamreza Arab Markadeh
Turkish Journal of Electrical Engineering and Computer Sciences
Nowadays, the use of flexible AC transmission systems (FACTS) is an economical and interesting approach to improve power transfer capability. The thyristor-controlled series capacitor, as a member of the FACTS family, can control interrelated parameters with dynamism due to its ability of rapid control and stabilization. Regardless of all of the works in this area, the control of transmitted power through the design of the firing angle controller is still missing. In this paper, first, the open-loop firing angle controller and its sensitivities are analyzed to fill in this gap. Next, closed-loop controllers such as PID and fuzzy controllers are …
Development And Optimization Of A Dsp-Based Real-Time Lane Detection Algorithm On A Mobile Platform, Gürkan Küçükyildiz, Hasan Ocak
Development And Optimization Of A Dsp-Based Real-Time Lane Detection Algorithm On A Mobile Platform, Gürkan Küçükyildiz, Hasan Ocak
Turkish Journal of Electrical Engineering and Computer Sciences
In this study, image processing-based real-time lane detection, which is one of the significant problems in autonomous vehicle control, is explored. A mobile robot platform is developed for that purpose. The motion of the mobile robot is provided by 4 direct current motors, which are independently controlled. An image processing code is developed in a Visual DSP 5.0 environment and run on a BF-561 processor embedded in the ADSP BF-561 EZ-KIT LITE evaluation board (Analog Devices). In the image processing algorithm, Hough lines obtained from the Hough transform of the captured images are called candidate lane marks. Various elimination methods …
A New Psfb Converter-Based Inverter Arc Welding Machine With High Power Density And High Efficiency, İsmai̇l Aksoy
A New Psfb Converter-Based Inverter Arc Welding Machine With High Power Density And High Efficiency, İsmai̇l Aksoy
Turkish Journal of Electrical Engineering and Computer Sciences
In this study, a high-performance single-phase inverter arc welding machine is presented. Power control of the developed welding machine is realized with a high-frequency, phase-shifted full bridge (PSFB) pulse-width modulation (PWM) converter. The PSFB PWM converter operates with soft switching at no load and full load. There is no need to use a passive snubber in the converter. Welding machine control is implemented with a digital signal processor (DSP) and phase-shift PWM IC. By means of the DSP, advanced arc welding functions and protection features such as short-circuit, over-current, and temperature protection are achieved. The current and voltage waveforms given …
Study On Interior Permanent Magnet Synchronous Motors For Hybrid Electric Vehicle Traction Drive Application Considering Permanent Magnet Type And Temperature, Javad Soleimani, Abolfazl Vahedi, Abdolhossein Ejlali, Mohammadhossein Barzegari Bafghi
Study On Interior Permanent Magnet Synchronous Motors For Hybrid Electric Vehicle Traction Drive Application Considering Permanent Magnet Type And Temperature, Javad Soleimani, Abolfazl Vahedi, Abdolhossein Ejlali, Mohammadhossein Barzegari Bafghi
Turkish Journal of Electrical Engineering and Computer Sciences
Recently, interior permanent magnet synchronous motors (Interior-PMSMs) have become known as a good candidate for hybrid electric vehicle (HEV) traction drive application due to their unique merits. However, the dynamic and steady-state behaviors of these motors are quite dependent on the permanent magnet (PM) type, configuration, and volume in rotor structures. This paper uses a novel structure of Interior-PMSMs for traction applications with fragmental buried rotor magnets in order to achieve low torque ripple, iron losses, and cogging torque. In this paper, first, the effect of the PM type on a d-q equivalent circuit model is examined. Next, the design …
Optimization Of Job Shop Scheduling Problems Using Modified Clonal Selection Algorithm, Yilmaz Atay, Hali̇fe Kodaz
Optimization Of Job Shop Scheduling Problems Using Modified Clonal Selection Algorithm, Yilmaz Atay, Hali̇fe Kodaz
Turkish Journal of Electrical Engineering and Computer Sciences
Artificial immune systems (AISs) are one of the artificial intelligence techniques studied a lot in recent years. AISs are based on the principles and mechanisms of the natural immune system. In this study, the clonal selection algorithm, which is used commonly in AISs, is modified. This algorithm is applied to job shop scheduling problems, which are one of the most difficult optimization problems. For applying application results to the optimum solution, parameter values giving the optimum solution are determined by analyzing the parameters in the algorithm. The obtained results are given in detail in the tables and figures. The best …
Contrast Enhancement Using Linear Image Combinations Algorithm (Ceulica) For Enhancing Brain Magnetic Resonance Images, Burak Yilmaz, Yüksel Özbay
Contrast Enhancement Using Linear Image Combinations Algorithm (Ceulica) For Enhancing Brain Magnetic Resonance Images, Burak Yilmaz, Yüksel Özbay
Turkish Journal of Electrical Engineering and Computer Sciences
Brain magnetic resonance imaging (MRI) images support important information about brain diseases for physicians. Morphological alterations in brain tissues indicate the probable existence of a disease in many cases. Proper estimation of these tissues, measuring their sizes, and analyzing their image patterns are parts of the diagnosis process. Therefore, the interpretability and perceptibility level of the MRI image is valuable for physicians. In this paper, a new image contrast enhancement algorithm based on linear combinations is presented. The proposed algorithm is focused on improving the interpretability and perceptibility of the image information. An MRI image is presented to the algorithm, …
Model-Free Controller With An Observer Applied In Real-Time To A 3-Dof Helicopter, Ahsene Boubakir, Salim Labiod, Fares Boudjema, Franck Plestan
Model-Free Controller With An Observer Applied In Real-Time To A 3-Dof Helicopter, Ahsene Boubakir, Salim Labiod, Fares Boudjema, Franck Plestan
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, a model-free controller with an observer is presented for a class of uncertain continuous-time multiinput-multioutput nonlinear dynamic systems. The proposed model-free control law consists of 2 parts: the first part is a linear control term used to specify the dynamics of the closed loop system, and the second part is a compensator of the effects of uncertainties and external disturbances. The compensator is synthesized from an estimator of the effects of uncertainties and disturbances based on the Lyapunov approach. In order to estimate the unavailable states of the controlled system, a linear state observer is designed. All …
Design And Implementation Of A Microcontroller Based Wind Energy Conversion System, Mehmet Demi̇rtaş, Şeri̇f Şerefoğlu
Design And Implementation Of A Microcontroller Based Wind Energy Conversion System, Mehmet Demi̇rtaş, Şeri̇f Şerefoğlu
Turkish Journal of Electrical Engineering and Computer Sciences
In this study, a dsPIC-controlled DC/DC boost converter and a wind turbine control system that tracks the maximum power point are designed and implemented. In practice, the energy generated by a permanent magnet synchronous wind turbine is applied to the load using a circuit that consists of a rectifier, boost converter, and protective load. The converter operates in the designed mode 35% more efficiently than in the normal operation mode. In addition, the wind turbine is protected from overvoltages in strong windy weather using the protective circuit. Experimental results show that the ripple value on the direct current belonging to …
Simulation Of A Flowing Snow Avalanche Using Molecular Dynamics, Deni̇zhan Güçer, Hali̇l Bülent Özgüç
Simulation Of A Flowing Snow Avalanche Using Molecular Dynamics, Deni̇zhan Güçer, Hali̇l Bülent Özgüç
Turkish Journal of Electrical Engineering and Computer Sciences
This paper presents an approach for the modeling and simulation of a flowing snow avalanche, which is formed of dry and liquefied snow that slides down a slope, using molecular dynamics and the discrete element method. A particle system is utilized as a base method for the simulation and marching cubes with real-time shaders are employed for rendering. A uniform grid-based neighbor search algorithm is used for collision detection for interparticle and particle-terrain interactions. A mass-spring model of the collision resolution is employed to mimic the compressibility of the snow and particle attraction forces are put into use between the …
Metaheuristic Linear Modeling Technique For Estimating The Excitation Current Of A Synchronous Motor, Hamdi̇ Tolga Kahraman
Metaheuristic Linear Modeling Technique For Estimating The Excitation Current Of A Synchronous Motor, Hamdi̇ Tolga Kahraman
Turkish Journal of Electrical Engineering and Computer Sciences
The subject of modeling and estimating of synchronous motor (SM) parameters is a challenge mathematically. Although effective solutions have been developed for nonlinear systems in artificial intelligence (AI)-based models, problems are faced with the application of these models in power circuits in real-time. One of these problems is the delay time resulting from a complex calculation process and thus the difficulties faced in the design of real-time motor driving circuits. Another important problem regards the difficulty in the realization of a complex AI-based model in microprocessor-based real-time systems. In this study, a new hybrid technique is developed to solve the …
A Penalty Function Method For Designing Efficient Robust Classifiers With Input Space Optimal Separating Surfaces, Ayşegül Uçar, Yakup Demi̇r, Cüneyt Güzeli̇ş
A Penalty Function Method For Designing Efficient Robust Classifiers With Input Space Optimal Separating Surfaces, Ayşegül Uçar, Yakup Demi̇r, Cüneyt Güzeli̇ş
Turkish Journal of Electrical Engineering and Computer Sciences
This paper considers robust classification as a constrained optimization problem. Where the constraints are nonlinear, inequalities defining separating surfaces, whose half spaces include or exclude the data depending on their classes and the cost, are used for attaining robustness and providing the minimum volume regions specified by the half spaces of the surfaces. The constraints are added to the cost using penalty functions to get an unconstrained problem for which the gradient descent method can be used. The separating surfaces, which are aimed to be found in this way, are optimal in the input data space in contrast to the …
On The Nilpotent Graph Of A Ring, Mohammad Javad Nikmehr, Soheila Khojasteh
On The Nilpotent Graph Of A Ring, Mohammad Javad Nikmehr, Soheila Khojasteh
Turkish Journal of Mathematics
Let R be a ring with unity. The nilpotent graph of R, denoted by \Gamma_N(R), is a graph with vertex set Z_N(R)^* = {0 \neq x \in R \mid xy \in N(R) for some 0 \neq y \in R}; and two distinct vertices x and y are adjacent if and only if xy \in N(R), where N(R) is the set of all nilpotent elements of R. Recently, it has been proved that if R is a left Artinian ring, then diam(\Gamma_N(R)) \leq 3. In this paper, we present a new proof for the above result, where R is a finite …
On The Centroid Of Prime Semirings, Hasret Yazarli, Mehmet Ali̇ Öztürk
On The Centroid Of Prime Semirings, Hasret Yazarli, Mehmet Ali̇ Öztürk
Turkish Journal of Mathematics
We define and study the extended centroid of a prime semiring. We show that the extended centroid is a semifield and give some properties of the centroid of a right multiplicatively cancellable prime semiring.
Products Of Conjugacy Classes And Products Of Irreducible Characters In Finite Groups, Mohammad Reza Darafsheh, Sajjad Mahmood Robati
Products Of Conjugacy Classes And Products Of Irreducible Characters In Finite Groups, Mohammad Reza Darafsheh, Sajjad Mahmood Robati
Turkish Journal of Mathematics
Let G be a finite group. If A and B are two conjugacy classes in G, then AB is a union of conjugacy classes in G and \eta(AB) denotes the number of distinct conjugacy classes of G contained in AB. If \chi and \psi are two complex irreducible characters of G, then \chi\psi is a character of G and again we let \eta(\chi\psi) be the number of irreducible characters of G appearing as constituents of \chi\psi. In this paper our aim is to study the product of conjugacy classes in a finite group and obtain an upper bound for \eta …
Global Existence, Decay And Blow Up Solutions For Coupled Nonlinear Wave Equations With Damping And Source Terms, Erhan Pi̇şki̇n, Necat Polat
Global Existence, Decay And Blow Up Solutions For Coupled Nonlinear Wave Equations With Damping And Source Terms, Erhan Pi̇şki̇n, Necat Polat
Turkish Journal of Mathematics
We study the initial-boundary value problem for a system of nonlinear wave equations with nonlinear damping and source terms, in a bounded domain. The decay estimates of the energy function are established by using Nakao's inequality. The nonexistence of global solutions is discussed under some conditions on the given parameters.
Bbm Equation With Non-Constant Coefficients, Amutha Senthilkumar
Bbm Equation With Non-Constant Coefficients, Amutha Senthilkumar
Turkish Journal of Mathematics
In this article, a model for the propagation of long waves over an uneven bottom is considered. We provide both theoretical and numerical results for this model. We also discuss the changes which occur in a solitary wave solution of the BBM equation as it travels through a channel of decreasing depth.
Second Order Approximations In Sequential Point Estimation Of The Probability Of Zero In Poisson Distribution, Eisa Mahmoudi, Mohammad Hatami Kamin
Second Order Approximations In Sequential Point Estimation Of The Probability Of Zero In Poisson Distribution, Eisa Mahmoudi, Mohammad Hatami Kamin
Turkish Journal of Mathematics
In the analysis of the count data, the Poisson model becomes overtly restrictive in the case of over-dispersed or under-dispersed data. When count data are under-dispersed, specific models such as generalized linear models (GLM) are proposed. Other examples are the zero-inflated Poisson model (ZIP) and zero-truncated Poisson model (ZTP), which have been used in literature to deal with an excess or absence of zeros in count data. Thus having a knowledge of the probability of zeros and its estimation in Poisson distribution can be significant and useful. Some estimation problems with unknown parameter cannot attain minimum risk where the sample …
Generalized Derivations Of Prime Rings On Multilinear Polynomials With Annihilator Conditions, Nurcan Argaç, Çağri Demi̇r
Generalized Derivations Of Prime Rings On Multilinear Polynomials With Annihilator Conditions, Nurcan Argaç, Çağri Demi̇r
Turkish Journal of Mathematics
Let K be a commutative ring with unity, R be a prime K-algebra with characteristic not 2, U be the right Utumi quotient ring of R, C the extended centroid of R, I a nonzero right ideal of R and a a fixed element of R. Let g be a generalized derivation of R and f(X_1,..., X_n) a multilinear polynomial over K. If ag(f(x_1,...,x_n))f(x_1,...,x_n)=0 for all x_1,...,x_n \in I, then one of the following holds: (1) aI=ag(I)=0; (2) g(x)=bx+[c,x] for all x\in R, where b,c\in U. In this case either [c,I]I=0=abI or aI=0=a(b+c)I; (3) [f(X_1,...,X_n),X_{n+1}]X_{n+2} is an identity for I.
Strongly Gorenstein Flat And Gorenstein Fp-Injective Modules, Chunhua Yang
Strongly Gorenstein Flat And Gorenstein Fp-Injective Modules, Chunhua Yang
Turkish Journal of Mathematics
In this paper, we first study the properties of strongly Gorenstein flat (resp. Gorenstein FP-injective) modules which are special Gorenstein projective (resp. Gorenstein injective) modules, and use them to prove that the global strongly Gorenstein flat dimension and the global Gorenstein FP-injective dimension of a ring R are identical when R is n-FC or commutative coherent. Finally, we show that if R is a commutative Noetherian ring, then, for any R-module M, SGfd_RM=Gpd_RM, and hence SGfd_RM< \infty if and only if Gfd_RM
Some Properties On The Baer-Invariant Of A Pair Of Groups And V_G-Marginal Series, Mohammad Reza Rismanchian, Mehdi Araskhan
Some Properties On The Baer-Invariant Of A Pair Of Groups And V_G-Marginal Series, Mohammad Reza Rismanchian, Mehdi Araskhan
Turkish Journal of Mathematics
The aim of this paper is to present some properties of the Baer-invariant of a pair of groups with respect to a given variety of groups V. We derive some equalities and inequalities of the Baer-invariant of a pair of finite groups, as long as V is considered to be a Schur-Baer variety. Moreover, we present a relative version of the concept of lower marginal series and give some isomorphisms among V_G-marginal factor groups. Also, we conclude a generalized version of the Stallings' theorem.
(P,\\Lambda)-Koszul Algebras And Modules, Ii, Jiafeng Lu
(P,\\Lambda)-Koszul Algebras And Modules, Ii, Jiafeng Lu
Turkish Journal of Mathematics
This paper is a continuous work of [14], where the notions of (p,\lambda)-Koszul algebra and (p,\lambda)-Koszul module were first introduced. More precisely, some new criteria for a positively graded algebra to be (p,\lambda)-Koszul are provided. We also generalize (p,\lambda)-Koszul objects to the nongraded case and define the so-called quasi-(p,\lambda)-Koszul objects. Further, the relationships between (quasi-) (p,\lambda)-Koszul modules and minimal Horseshoe Lemma are established.
G-Frames As Special Frames, Abas Askarizadeh, Mohammad Ali Dehghan
G-Frames As Special Frames, Abas Askarizadeh, Mohammad Ali Dehghan
Turkish Journal of Mathematics
G-frames are generalizations of ordinary frames for Hilbert spaces. In the present paper we study frames, and operators on a special separable Hilbert C^*-module, B(H,K), where H and K are Hilbert spaces, and we prove that every g-frame for H is a frame for B(H,K) and vice versa. Also, we derive some relationships between g-Riesz bases for H and Riesz bases in B(H,K). Similar results for orthogonal bases will be discussed.
Rings Over Which Every Module Has A Flat \\Delta-Cover, Pinar Aydoğdu
Rings Over Which Every Module Has A Flat \\Delta-Cover, Pinar Aydoğdu
Turkish Journal of Mathematics
Let M be a module. A \delta-cover of M is an epimorphism from a module F onto M with a \delta-small kernel. A \delta-cover is said to be a flat \delta-cover in case F is a flat module. In the present paper, we investigate some properties of (flat) \delta-covers and flat modules having a projective \delta-cover. Moreover, we study rings over which every module has a flat \delta-cover and call them right generalized \delta-perfect rings. We also give some characterizations of \delta-semiperfect and \delta-perfect rings in terms of locally (finitely, quasi-, direct-) projective \delta-covers and flat \delta-covers.
Global And Finitistic Dimension Of Hopf-Galois Extensions, Ling Liu, Qiaoling Guo
Global And Finitistic Dimension Of Hopf-Galois Extensions, Ling Liu, Qiaoling Guo
Turkish Journal of Mathematics
Let H be a Hopf algebra over a field k and A/B a right H-Galois extension. Then in this note a spectral sequence for Ext will be constructed which yields the estimate for global dimension of A in terms of the corresponding data for H and B. As an application, we obtain the Maschke-type theorems for crossed products and twisted smash products. Finally, the relationship of finitistic dimensions between A and B will be given, if H is semisimple.
Existence And Multiplicity Of Positive Solutions For A Class Of Nonlinear Elliptic Problems, Asadollah Aghajani, Jamile Shamshiri, Frajollah Mohammadi Yaghoobi
Existence And Multiplicity Of Positive Solutions For A Class Of Nonlinear Elliptic Problems, Asadollah Aghajani, Jamile Shamshiri, Frajollah Mohammadi Yaghoobi
Turkish Journal of Mathematics
We study the existence and multiplicity of nonnegative solutions for the nonlinear elliptic problem, -\Delta u+v(x)u=a(x)u^p+\lambda f(x,u) for x\in\Omega and u=0 on \partial\Omega, where \Omega is a bounded region in R^N, N>2, 1
Sasakian Finsler Manifolds, Ayşe Funda Yaliniz, Nesri̇n Çalişkan
Sasakian Finsler Manifolds, Ayşe Funda Yaliniz, Nesri̇n Çalişkan
Turkish Journal of Mathematics
In this study, almost contact Finsler structures on vector bundle are defined and the condition of normality in terms of the Nijenhuis torsion N_{\phi} of almost contact Finsler structure is obtained. It is shown that for a K-contact structure on Finsler manifold \nabla_X \xi =-\frac{1}{2} \phi X and the flag curvature for plane sections containing \xi are equal to \frac{1}{4}. By using the Sasakian Finsler structure, the curvatures of a Finsler connection \nabla on V are obtained. We prove that a locally symmetric Finsler manifold with K-contact Finsler structure has a constant curvature \frac{1}{4}. Also, the Ricci curvature on Finsler …