Open Access. Powered by Scholars. Published by Universities.®
- Discipline
- Keyword
-
- Turkey (129)
- 1 (99)
- 2 (83)
- Classification (75)
- Deep learning (75)
-
- Machine learning (72)
- Optimization (69)
- Genetic algorithm (62)
- Synthesis (62)
- Adsorption (58)
- Geochemistry (55)
- Particle swarm optimization (53)
- Antimicrobial activity (47)
- 3 (45)
- Artificial neural network (42)
- Stability (40)
- Support vector machine (37)
- Phthalocyanine (36)
- Antibacterial activity (33)
- Feature extraction (33)
- Artificial neural networks (32)
- Feature selection (31)
- Wireless sensor networks (31)
- Molecular docking (30)
- Copper (28)
- Cytotoxicity (28)
- DFT (28)
- Oscillation (28)
- Power quality (28)
- COVID-19 (27)
- Publication Year
Articles 10471 - 10500 of 12081
Full-Text Articles in Entire DC Network
Cover And Contents
Turkish Journal of Electrical Engineering and Computer Sciences
No abstract provided.
Pyrite Deformation Textures In The Deposits Of The Küre Mining District (Kastamonu-Turkey), İlkay Kuşcu, Ayhan Erler
Pyrite Deformation Textures In The Deposits Of The Küre Mining District (Kastamonu-Turkey), İlkay Kuşcu, Ayhan Erler
Turkish Journal of Earth Sciences
The Küre volcanogenic massive sulfide deposits lie within the Kastamonu province in the western part of the Pontide tectonic belt of Turkey, and are hosted by ophiolite-related pre-Liassic basaltic sequences. Mineralogical studies of the pyritic massive sulfide deposits of the Küre mining district have shown that the sulfide assemblages, particularly pyrite, have undergone a history of deformation and metamorphism. The Küre volcanogenic massive sulfide deposits show a range of macroscopic and microscopic textures, which are also observed in metamorphosed VMS deposits elsewhere. These textures are cataclastic, annealing and fracture-filling textures which developed in two successive stages; cataclastic texture predominated during …
Cpl: A Language For Real-Time Distributed Object Programming, Erhan Saridoğan, Nadi̇a Erdoğan
Cpl: A Language For Real-Time Distributed Object Programming, Erhan Saridoğan, Nadi̇a Erdoğan
Turkish Journal of Electrical Engineering and Computer Sciences
As processing and time requirements of computer systems increase over the borders of single processor architectures, it is becoming more and more attractive to use distributed computing with additional real-time capabilities. In several cases, traditional programming languages have become insufficient to build distributed systems easily, especially when real-time issues and basic software quality factors are concerned. In this paper, a concurrent, object-oriented, distributed real-time programming language, CPL, with a supportive run-time system, namely the CORD-RTS, is introduced and new language features are described. The new language provides an efficient solution for command and control systems by embedding distribution and real-time …
An Efficient Middleware Architecture Supporting Real-Time Distributed Object Programming, Erhan Saridoğan, Nadi̇a Erdoğan
An Efficient Middleware Architecture Supporting Real-Time Distributed Object Programming, Erhan Saridoğan, Nadi̇a Erdoğan
Turkish Journal of Electrical Engineering and Computer Sciences
With the increasing demand for distributed real-time systems, the need for programming tools and execution platforms useful in development of such application systems is widely recognized. This paper presents CORD-RTS, an efficient middleware architecture that provides support for real-time distributed object programming. The communication infrastructure and various components of the middleware, which support several modes of interactions among distributed real-time objects, along with its real-time features and services, are discussed in detail.
A New Congestion Control Mechanism Proposed For The Sscop Protocol, A. Hali̇m Zai̇m
A New Congestion Control Mechanism Proposed For The Sscop Protocol, A. Hali̇m Zai̇m
Turkish Journal of Electrical Engineering and Computer Sciences
International Telecommunication Union, Telecommunications Sector (ITU-T) Recommendation Q.2110 states that the update of a granted credit window to the transmitter (VR(MR)) is implementation dependent. In this paper, a new algorithm is designed to control the traffic flow coming from malfunctioning users. The VR(MR) parameter is controlled for that purpose. The simulation results show that this new technique nearly doubles the system performance.
Walkthrough In Complex Environments At Interactive Rates Using Level-Of-Detail, Alper Selçuk, Uğur Güdükbay, Bülent Özgüç
Walkthrough In Complex Environments At Interactive Rates Using Level-Of-Detail, Alper Selçuk, Uğur Güdükbay, Bülent Özgüç
Turkish Journal of Electrical Engineering and Computer Sciences
One of the biggest problems in computer graphics is displaying huge geometric models at interactive rates. A lot of work has been done to achieve the required frame-rates in architecture, simulation, computer-aided design and entertainment applications. In this paper, a system that enables walkthrough in complex environments using level-of-detail approximations is explained. The system uses hierarchical triangulated models as input. In the preprocessing phase, multiresolution models of objects are created using polygonal simplification techniques. During walkthrough, fast frustum culling based on bounding boxes is performed to eliminate branches of hierarchy that are not visible. An appropriate level for detail of …
A New Petri-Net-Based Synthesis Technique For Supervisory Control Of Discrete Event Systems, Murat Uzam, Anthony H. Jones
A New Petri-Net-Based Synthesis Technique For Supervisory Control Of Discrete Event Systems, Murat Uzam, Anthony H. Jones
Turkish Journal of Electrical Engineering and Computer Sciences
A new Petri-net-based top-down synthesis technique for supervisory control of Discrete Event Systems (DES) is proposed to solve the forbidden state problem. The supervisors obtained are compiled supervisors, whose control policy is represented as a net structure, as opposed to mapping supervisors, whose control policy is computed as a feedback function of the marking of the system. The compiled supervisors obtained by using the technique proposed in this paper are both nonblocking and maximally permissive. The supervisors to be synthesised consist of a controlled Automation Petri Net model of the system. Automation Petri Nets (APN) include the following extensions to …
Approximations On The Aggregate Mpeg Video Traffic And Their Impact On Admission Control, Fati̇h Alagöz
Approximations On The Aggregate Mpeg Video Traffic And Their Impact On Admission Control, Fati̇h Alagöz
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, we investigate the aggregate traffic approximations for the Motion Pictures Expert Group (MPEG) coded variable bit rate (VBR) video traffic and their impact on admission control at a desired Quality of Service (QoS) level. In order to generate the MPEG coded VBR video traffic, we use a novel source model that employs a mixture of two first-order autoregressive processes with lognormally distributed residuals (2LAR). The model parameters are found based on least square estimates to capture the marginal distribution and autocorrelation function as well as the single server queuing behavior of an MPEG coded empirical bitstream. We …
New Oscillator Topologies Using Inverting Second-Generation Current Conveyors, Ali̇ Toker, Hakan Kuntman, Oğüzhan Çi̇çekoğlu, Mehmet Di̇şçi̇gi̇l
New Oscillator Topologies Using Inverting Second-Generation Current Conveyors, Ali̇ Toker, Hakan Kuntman, Oğüzhan Çi̇çekoğlu, Mehmet Di̇şçi̇gi̇l
Turkish Journal of Electrical Engineering and Computer Sciences
In this work, new oscillator topologies based on a recently introduced active element, namely inverting second-generation current conveyor, are presented. This recently introduced unity gain based active element is suitable for integrated circuit realization and can easily be implemented with CMOS technology. Considering this fact, basic oscillator topologies employing a single, two and three conveyors are proposed. Several oscillator circuits based on these topologies are obtained. Expressions for oscillation conditions and frequencies are derived both for ideal and non-ideal cases. Some of them are single frequency and the others are variable frequency oscillators. The oscillators employing two and three active …
Cover And Contents
Turkish Journal of Electrical Engineering and Computer Sciences
No abstract provided.
Preface, Levent Sevgi̇
Preface, Levent Sevgi̇
Turkish Journal of Electrical Engineering and Computer Sciences
No abstract provided.
Electromagnetic Engineering In The 21^{St} Century: Challenges And Perspectives, Leopold B. Felsen, Levent Sevgi̇
Electromagnetic Engineering In The 21^{St} Century: Challenges And Perspectives, Leopold B. Felsen, Levent Sevgi̇
Turkish Journal of Electrical Engineering and Computer Sciences
This paper aims at a broad-brush look at certain technological and educational challenges that confront wave-oriented electromagnetic (EM) engineering in the 21^{st} century, in a complex computer and technology-driven world with rapidly shifting societal and technical priorities. Simulation strategies for complex EM systems, both analytic and numerical, are reviewed and categorized, and are illustrated on selected practical complex multicomponent system scenarios currently under investigation in Turkey. Educational issues to ensure proper multidisciplinary exposure of new generations of computer-weaned students, who will have to deal with these problems, are touched upon as well.
Time-Domain Simulation Of Thin Material Boundaries And Thin Panels Using Digital Filters In Tlm, J. Paul, V. Podlozny, Dave Thomas, C. Christopoulos
Time-Domain Simulation Of Thin Material Boundaries And Thin Panels Using Digital Filters In Tlm, J. Paul, V. Podlozny, Dave Thomas, C. Christopoulos
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, the design and implementation of digital filters for the time-domain simulation of electromagnetic wave interaction with thin material boundaries and thin panels using the Transmission-Line Modelling (TLM) method are described. The technique is applied to the description of thin ferrite layers placed on the external boundaries of the modelled space and to plastic panels placed inside the modelled space. The approach is validated using one-dimensional examples having analytic solutions. Finally, the results obtained for the Shielding Effectiveness (SE) of a practical equipment enclosure are presented to demonstrate the utility of the method in Electromagnetic Compatibility (EMC) prediction.
Aspects Of Radar Polarimetry, Ernst Luneburg
Aspects Of Radar Polarimetry, Ernst Luneburg
Turkish Journal of Electrical Engineering and Computer Sciences
This contribution is a tutorial introduction to the phenomenological theory of radar polarimetry for the coherent scatter case emphasizing monostatic backscattering and forward scattering (transmission). Characteristic similarities and differences between radar polarimetry and optical polarimetry and the role of linear and antilinear operators (time-reversal) are pointed out and typical polarimetric invariants are identified.
Two-Dimensional Photonic Crystal L-Shaped Bent Waveguide And Its Application To Wavelength Multi/Demultiplexer, Yoshihiro Naka, Hiroyoshi Ikuno
Two-Dimensional Photonic Crystal L-Shaped Bent Waveguide And Its Application To Wavelength Multi/Demultiplexer, Yoshihiro Naka, Hiroyoshi Ikuno
Turkish Journal of Electrical Engineering and Computer Sciences
The bent waveguide is a key element for integrated optical signal processing waveguide devices. We propose a new type of two-dimensional photonic crystal L-shaped bent waveguides with additional pillars at the corner. Using the FDTD method based on the principle of multidimensional wave digital filters we simulate its transmission characteristics and show an excellent transmission of light in L-shaped bent waveguide. As an application we design compact size multi/demultiplexer composed of the L-shaped bent waveguides and directional couplers and realize multi/demultiplexer with low-insertion loss and high extinction ratio device whose size is of the order of the wavelength of light.
Discrete Array Representation Of Continuous Space-Time Source Distributions, Amir Shlivinski, Ehud Heyman
Discrete Array Representation Of Continuous Space-Time Source Distributions, Amir Shlivinski, Ehud Heyman
Turkish Journal of Electrical Engineering and Computer Sciences
We consider the realization of a continuous space-time source distributions using a sparse non-uniform point-source array. The construction determines the largest possible cells corresponding to the local source parameters in order to obtain a sparse array, while meeting an error criterion on the pulsed radiation pattern. The scheme is applied for the realization of collimated short-pulse beam fields. The error criterion is imposed within the main beam direction, while outside this region the relative realization error can be large but it is negligible since the field there is small compared to the main beam field.
Development Of A Cylindrical Waveguide Antenna Array With A High Isolation Between Receive - Transmit Sub Arrays: Theory And Experiment, Vladimir I. Okhmatovsky, Konstantina S. Nikita, Stavros Koulouridis, Nikolaos K. Uzunoglu
Development Of A Cylindrical Waveguide Antenna Array With A High Isolation Between Receive - Transmit Sub Arrays: Theory And Experiment, Vladimir I. Okhmatovsky, Konstantina S. Nikita, Stavros Koulouridis, Nikolaos K. Uzunoglu
Turkish Journal of Electrical Engineering and Computer Sciences
The possibility of developing an antenna system consisting of transmit and receive arrays and being able to work simultaneously in full duplex mode at the same frequency is a very attractive task. This could only be achieved if the isolation between the transmit and receive arrays is sufficiently high not to cause a parasitic oscillation which will ruin the proper operation of a transponder system to which the arrays will be connected. Specifically, in this paper the operation of two peripheral open waveguide arrays placed on a cylindrical surface and being isolated with a radial line operating as a space …
2d Complex Point Source Radiation Problem I. Complex Distances And Complex Angles, E. Gago-Ribas, M. J. Gonzalez Morales
2d Complex Point Source Radiation Problem I. Complex Distances And Complex Angles, E. Gago-Ribas, M. J. Gonzalez Morales
Turkish Journal of Electrical Engineering and Computer Sciences
A methodology based on the complex spaces analysis, which allows to generalize the study of wave radiation and scattering problems is presented in this paper. From the analytic continuation of functions defined in the real domain (real propagation or scattering spaces) into the complex space (space of complex coordinates), general non homogeneous phase field solutions are obtained for a particular wave problem. From these general solutions, other common solutions obtained under different approximations will arise. This procedure allows to obtain a complete classification of the solutions for the wave problem under analysis, and also to study both the ranges of …
2d Complex Point Source Radiation Problem Ii.~Complex Beams, M. J. Gonzalez Morales, E. Gago-Ribas
2d Complex Point Source Radiation Problem Ii.~Complex Beams, M. J. Gonzalez Morales, E. Gago-Ribas
Turkish Journal of Electrical Engineering and Computer Sciences
The complex point source analytic continuation, and the analysis into the spaces of complex distances, angles, and other related magnitudes, may be applied to describe a wide variety of 2D wave propagation problems. This step will be essential in order to establish a complete complex methodology which may be applied to obtain general descriptions of more practical problems involving the scattering of waves under some kind of field incidence. A particular application of the methodology presented in Part I will be used in Part II. The specific problem under analysis in these papers will be the general complex beam solution …
An Efficient Preconditioner For Iterative Solvers, V. V. S. Prakash, Raj Mittra
An Efficient Preconditioner For Iterative Solvers, V. V. S. Prakash, Raj Mittra
Turkish Journal of Electrical Engineering and Computer Sciences
The method of moments solution of the Maxwell's equations leads to a dense system of complex equations. Direct solution of these equations using LU factorization becomes unwieldy as the size of the scatterer increase in terms of wavelength. Iterative solvers, such as those based on Krylov projection methods, offer an alternative approach for solving large system of equations. Most often, the iterative methods are used in combination with some kind of preconditioning to improve the condition number of the system matrix A in order to acheive accelerated convergence [1-2]. This paper discusses the application of Multi-Frontal Preconditioners (MFPs) for the …
A Note On The Poisson Summation Formula And Its Application To Electromagnetic Problems Involving Cylindrical Coordinates, Anastassios H. Panaretos, Hristos T. Anastassiu, Dimitra I. Kaklamani
A Note On The Poisson Summation Formula And Its Application To Electromagnetic Problems Involving Cylindrical Coordinates, Anastassios H. Panaretos, Hristos T. Anastassiu, Dimitra I. Kaklamani
Turkish Journal of Electrical Engineering and Computer Sciences
A modified version of the Poisson Summation Formula is derived,involving the Fourier-Bessel Transform of the kernel function, as opposed to the conventional Fourier Transform engaged in the standard formula. This novel form can be applied to problems employing cylindrical coordinates, such as the fast evaluation of the dyadic Green's function in a waveguide or cavity of circular cross-section.
A Time Domain Uniform Geometrical Theory Of Slope Diffraction For A Curved Wedge, Prabhakar H. Pathak, Paul R. Rousseau
A Time Domain Uniform Geometrical Theory Of Slope Diffraction For A Curved Wedge, Prabhakar H. Pathak, Paul R. Rousseau
Turkish Journal of Electrical Engineering and Computer Sciences
A time domain version of the uniform geometrical theory of diffraction (TD-UTD) is developed to describe, in essentially closed form, the field which is produced via slope diffraction at a perfectly conducting, arbitrarily curved wedge excited by a time impulsive wave that exhibits a rapid spatial variation near the edge of the wedge. This TD-UTD slope diffracted field for a curved wedge is obtained by a Fourier inversion of the corresponding frequency domain UTD expression. An analytical signal representation of the transient fields is used since it is convenient, and because it circumvents some of the difficulties, which especially arise …
A Novel Mom Approach For Obtaining Accurate And Efficient Solutions In Optical Rib Waveguide, Namik Yener, Ercan Topuz
A Novel Mom Approach For Obtaining Accurate And Efficient Solutions In Optical Rib Waveguide, Namik Yener, Ercan Topuz
Turkish Journal of Electrical Engineering and Computer Sciences
The optical rib waveguide (ORW) plays an important role in the design of several integrated optical devices. Various methods have been proposed for obtaining the modal field solutions in ORW. However, to the best of our knowledge none of them is capable of providing accurate full-wave benchmark solutions. Here we present a novel MoM approach wherein the modes of a loaded rectangular waveguide are utilized as basis functions and demonstrate that this approach is very efficient and yields highly accurate full-wave results which can serve as benchmark solutions in assessing the quality of the data reported in the literature.
Effects Of Substrate Temperature On Properties Of A-Sin_X:H Films, Tayyar Güngör, Hüseyi̇n Tolunay
Effects Of Substrate Temperature On Properties Of A-Sin_X:H Films, Tayyar Güngör, Hüseyi̇n Tolunay
Turkish Journal of Physics
Hydrogenated amorphous silicon nitride films were prepared in an rf glow-discharge system by the decomposition of silane + nitrogen gas mixture at various substrate temperatures. The effects of substrate temperature on the electrical and optical properties of the films have been studied.
The Temperature Dependence Of The Electronic Structure Of Si \Delta-Doped Gaas, Emi̇ne Öztürk
The Temperature Dependence Of The Electronic Structure Of Si \Delta-Doped Gaas, Emi̇ne Öztürk
Turkish Journal of Physics
We investigated theoretically the change of electronic properties of Si \delta-doped GaAs layer as a function of temperature. We studied the influence of temperature on the donor concentration for a nonuniform distribution, which is taken as different from the known Gaussian distribution. In order to obtain the electronic structure we have calculated self-consistent Schrödinger - Poisson equations. We have seen that the change of the electronic properties as dependent on temperature is less pronounced at higher doping concentration.
Defect Structure Of Glow Peak 1 In Lif:Mg,Ti (Tld-100), A. Necmeddi̇n Yazici
Defect Structure Of Glow Peak 1 In Lif:Mg,Ti (Tld-100), A. Necmeddi̇n Yazici
Turkish Journal of Physics
The possible defect structure of peak 1 of LiF:Mg,Ti (TLD-100) was studied in the present work after different pre-irradiation heat treatments between 80°C and 150°C using the computer glow curve deconvolution (CGCD) method. It was shown that the defect structure of peak 1 is based on colloid centers, Ti^{+4}-3O_{2}^{-}-mixed centers and U_{1}-centers.
Cover And Contents
Turkish Journal of Veterinary & Animal Sciences
No abstract provided.
Effect Of Rf Power On The Electrical Properties Of Glow-Discharge A-Si:H, Hüseyi̇n Tolunay
Effect Of Rf Power On The Electrical Properties Of Glow-Discharge A-Si:H, Hüseyi̇n Tolunay
Turkish Journal of Physics
Hydrogenated amorphous silicon films were prepared in an rf glow-discharge system by decomposing undiluted silane at various rf power densities. Dark conductivity and photoconductivity of the films have been measured in the temperature range 420K-100K at four different photon fluxes. It was observed that both dark conductivity and photoconductivity increase with increasing rf power density.