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 8761 - 8790 of 10319
Full-Text Articles in Physical Sciences and Mathematics
An Implicit Surface Modeling Technique Based On A Modular Neural Network Architecture, Manuel Carcenac
An Implicit Surface Modeling Technique Based On A Modular Neural Network Architecture, Manuel Carcenac
Turkish Journal of Electrical Engineering and Computer Sciences
Independently from artificial intelligence applications, an artificial neural network can be viewed as a powerful tool for function reconstruction. Previous papers used this property to model an implicit surface out of some control points by reconstructing its underlying scalar field. Such an approach requests the neural network to memorize the control points, which has turned problematic for complex surfaces. In our paper, we show that this problem can be efficiently tackled by adapting the architecture of the neural network to the features compounding the surface: by learning first these features independently and then blending them gradually together, our modular architecture …
Real-Time Classification Algorithm For Recognition Of Machine Operating Modes By Use Of Self-Organizing Maps, Gancho Vachkov, Yuhiko Kiyota, Koji Komatsu, Satoshi Fujii
Real-Time Classification Algorithm For Recognition Of Machine Operating Modes By Use Of Self-Organizing Maps, Gancho Vachkov, Yuhiko Kiyota, Koji Komatsu, Satoshi Fujii
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper a new algorithm for classification and real-time recognition of different a-priorily assumed operating modes for construction machines is proposed. This algorithm utilizes the effectiveness of the Self-Organizing Maps (SOM) for creating the so called Separation Models, that are able to distinguish each operating mode separately. After training, these models are used in a real-time procedure, which calculates at each sampling time the minimal Euclidean distances from the current data point to a certain node of each SOM. Then the separation model (represented by a respective SOM) that has the least minimal distance to this data point defines …
A Simple And Global Optimization Algorithm For Engineering Problems: Differential Evolution Algorithm, Dervi̇ş Karaboğa, Selçuk Ökdem
A Simple And Global Optimization Algorithm For Engineering Problems: Differential Evolution Algorithm, Dervi̇ş Karaboğa, Selçuk Ökdem
Turkish Journal of Electrical Engineering and Computer Sciences
Differential Evolution (DE) algorithm is a new heuristic approach mainly having three advantages; finding the true global minimum regardless of the initial parameter values, fast convergence, and using few control parameters. DE algorithm is a population based algorithm like genetic algorithms using similar operators; crossover, mutation and selection. In this work, we have compared the performance of DE algorithm to that of some other well known versions of genetic algorithms: PGA, Grefensstette, Eshelman. In simulation studies, De Jong's test functions have been used. From the simulation results, it was observed that the convergence speed of DE is significantly better than …
The 7 C'S For Creating Living Software: A Research Perspective For Quality-Oriented Software Engineering, Mehmet Akşi̇t
The 7 C'S For Creating Living Software: A Research Perspective For Quality-Oriented Software Engineering, Mehmet Akşi̇t
Turkish Journal of Electrical Engineering and Computer Sciences
This article proposes the 7 C's for realizing quality-oriented software engineering practices. All the desired qualities of this approach are expressed in short by the term living software. The 7 C's are: Concern-oriented processes, Canonical models, Composable models, Certifiable models, Constructible models, Closure property of models and Controllable models. Each C is explained by the help of a set of definitions, a short overview of the background work and the problems that software engineers may experience in realizing the corresponding C. Further, throughout the article, a software development example is presented for illustrating the realization of the 7 C's. Finally, …
An Information System For Streamlining Software Development Process, Serkan Nalbant
An Information System For Streamlining Software Development Process, Serkan Nalbant
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper an information system to be employed by software development organizations is proposed, which automates software development process. The proposed system aims to lower cost, improve schedule performance and enhance quality of the software projects by the means of automation and unifying of operational information. The characteristics of the proposed system are described. Furthermore, its use is illustrated via the explanation of an exemplary software system called PACE that serves as an information system for planning, controlling, measuring and improving software development process and projects. The relationship of PACE with Software Capability Maturity Model (CMM) is also provided.
A Pattern Based Approach To Web Design Formalization, Ahmet Sikici, Yasemi̇n Topaloğlu
A Pattern Based Approach To Web Design Formalization, Ahmet Sikici, Yasemi̇n Topaloğlu
Turkish Journal of Electrical Engineering and Computer Sciences
World Wide Web is a global information network that affects many fields of our lives. The distributed, interlinked, visual and heterogeneous structure of the web makes it an irregular development environment. In this paper we propose a pattern based approach for increasing the effectiveness of development for the Web environment. This approach is based on the representation of the core meaning of each design as a set of patterns and requires the formulation of abstract solutions in a mathematical precision. This way not only reusable design experience will be codified unambiguously, but a smooth transition between the design and implementation …
An Agile Information Systems Development Method In Use, Mehmet Nafi̇z Aydin, Frank Harmsen, Kees Van Slooten, Robert Stegwee
An Agile Information Systems Development Method In Use, Mehmet Nafi̇z Aydin, Frank Harmsen, Kees Van Slooten, Robert Stegwee
Turkish Journal of Electrical Engineering and Computer Sciences
Recently, agile information systems development methods, agile methods in short, have got considerable attention from practitioners. One of the reasons seems that agile methods, to some degree, can be adaptable to different project situations. However, little empirical research has been conducted on this subject. The major goal of this research is to identify which aspects of agile methods are perceived as most critical and difficult to realize and how such aspects are adapted in practice. To reach this goal we studied the working practices concerning the adaptation of an agile method in the IT department of one of the leading …
A Robustness Analysis Of Game-Theoretic Cdma Power Control, Xingzhe Fan, Murat Arcak, John T. Wen
A Robustness Analysis Of Game-Theoretic Cdma Power Control, Xingzhe Fan, Murat Arcak, John T. Wen
Turkish Journal of Electrical Engineering and Computer Sciences
This paper studies robustness of a gradient-type CDMA uplink power control algorithm with respect to disturbances and time-delays. This problem is of practical importance because unmodeled secondary interference effects from neighboring cells play the role of disturbances, and propagation delays are ubiquitous in wireless data networks. We first show L_p-stability, for p \in [1,\infity], with respect to additive disturbances. We pursue L_{\infity}-stability within the input-to-state stability (ISS) framework of Sontag [7], which makes explicit the vanishing effect of the initial conditions. Next, using the ISS property and a loop transformation, we prove that global asymptotic stability is preserved for sufficiently …
Global Stability Analysis Of An End-To-End Congestion Control Scheme For General Topology Networks With Delay, Tansu Alpcan, Tamer Başar
Global Stability Analysis Of An End-To-End Congestion Control Scheme For General Topology Networks With Delay, Tansu Alpcan, Tamer Başar
Turkish Journal of Electrical Engineering and Computer Sciences
We analyze the stability properties of an end-to-end congestion control scheme under fixed heterogeneous delays, and for general network topologies. The scheme analyzed is based on the congestion control game of [1], with the starting point being the unique Nash equilibrium of that game. We prove global stability of this solution (and hence of the congestion control algorithm) under a mild symmetricity condition. We further demonstrate the stability of the algorithm numerically for various delays, user numbers, and topologies
Flow Controller Design And Performance Analysis For Self-Similar Network Traffic, Peng Yan
Flow Controller Design And Performance Analysis For Self-Similar Network Traffic, Peng Yan
Turkish Journal of Electrical Engineering and Computer Sciences
Recent studies of high-resolution traffic measurement discovered the self-similarity in both LAN and WAN traffic. In this paper, we introduce a two-degree of freedom rate based flow controller, which includes a robust H^{\infity} control block and an LMMSE based capacity predictor. The former part can guarantee the robust stability against time-varying time delay uncertainties and the latter improves the transient response by predicting the self-similar cross-traffic. Implementation issues are discussed and performance analysis is provided to validate our design. We also investigate the prediction and control in larger time scale which is more applicable for the real network environment
Determination Of H_{2}O_{2} Content Of Various Water Samples Using A Chemiluminescence Technique, Tuğba Tüğsüz, Elmas Gök, Serdar Ateş
Determination Of H_{2}O_{2} Content Of Various Water Samples Using A Chemiluminescence Technique, Tuğba Tüğsüz, Elmas Gök, Serdar Ateş
Turkish Journal of Chemistry
Hydrogen peroxide (H_{2}O_{2}) plays an important role in natural water samples. In this study H_{2}O_{2} concentrations were quantified in different water samples by chemiluminescence detection. This method was chosen because of its high sensitivity and suitability for determining low concentrations of H_{2}O_{2}. H_{2}O_{2} is introduced to the oxidation reaction of alkaline luminol solutions in the presence of Co^{2 + } ion catalyst. When these components are mixed, blue light (\lambda = 440 nm) is emitted. Maximum chemiluminescence intensity occurs within 2 s after mixing and is continuous for up to a few minutes, permitting accurate measurements at selected delay times. …
Affine Manifolds, Log Structures, And Mirror Symmetry, Mark Gross, Bernd Siebert
Affine Manifolds, Log Structures, And Mirror Symmetry, Mark Gross, Bernd Siebert
Turkish Journal of Mathematics
We outline work in progress suggesting an algebro-geometric version of the Strominger-Yau-Zaslow conjecture. We define the notion of a toric degeneration, a special case of a maximally unipotent degeneration of Calabi-Yau manifolds. We then show how in this case the dual intersection complex has a natural structure of an affine manifold with singularities. If the degeneration is polarized, we also obtain an intersection complex, also an affine manifold with singularities, related by a discrete Legendre transform to the dual intersection complex. Finally, we introduce log structures as a way of reversing this construction: given an affine manifold with singularities with …
Duality And Fibrations On G_2 Manifolds, Sergei Gukov, Shing-Tung Yau, Eric Zaslow
Duality And Fibrations On G_2 Manifolds, Sergei Gukov, Shing-Tung Yau, Eric Zaslow
Turkish Journal of Mathematics
We argue that G_2 manifolds for M-theory admitting string theory Calabi-Yau duals are fibered by coassociative submanifolds. Dual theories are constructed using the moduli space of M-five-brane fibers as target space. Mirror symmetry and various string and M-theory dualities involving G_2 manifolds may be incorporated into this framework. To give some examples, we construct two non-compact manifolds with G_2 structures: one with a K3 fibration, and one with a torus fibration and a metric of G_2 holonomy. Kaluza-Klein reduction of the latter solution gives abelian BPS monopoles in 3 + 1 dimensions.
On Some Properties Of Szasz-Mirakyan Operators In Hölder Spaces, Zbigniew Walczak, Lucyna Rempulska
On Some Properties Of Szasz-Mirakyan Operators In Hölder Spaces, Zbigniew Walczak, Lucyna Rempulska
Turkish Journal of Mathematics
We study some properties of modified Szasz-Mirakyan operators in Hölder exponential weighted spaces. We give theorems on the degree of approximation of functions by these operators.
Shape Operator A_H For Slant Submanifolds In Generalized Complex Space Forms, Adela Mihai
Shape Operator A_H For Slant Submanifolds In Generalized Complex Space Forms, Adela Mihai
Turkish Journal of Mathematics
In this article, we establish an inequality between the sectional curvature function K and the shape operator A_H at the mean curvature vector for slant submanifolds in generalized complex space forms. Also a sharp relationship between the k-Ricci curvature and the shape operator A_H is proved.
Change Of Birefringence In Dye-Doped Nematic Liquid Crystals Under Laser Illumination, S. Eren San, Oğuz Köysal, Serhat Özder, F. Necati̇ Ecevi̇t
Change Of Birefringence In Dye-Doped Nematic Liquid Crystals Under Laser Illumination, S. Eren San, Oğuz Köysal, Serhat Özder, F. Necati̇ Ecevi̇t
Turkish Journal of Physics
Birefringence property of E7 nematic liquid crystal is investigated via voltage dependent transmittance spectrums. Measurements are performed at wavelength 632.8 nm, which is the absorbance peak of our sample including anthraquinone derivative Disperse Blue 14. Results of dye-doped samples are compared with those undoped for dark and laser illuminated cases. It was observed that birefringence is dependent on laser illumination for dye-doped samples, up to a threshold voltage after which it is constant.
Network Traffic Properties Of Bimodal Multicast Protocol, Öznur Özkasap, Mi̇ne Çağlar
Network Traffic Properties Of Bimodal Multicast Protocol, Öznur Özkasap, Mi̇ne Çağlar
Turkish Journal of Electrical Engineering and Computer Sciences
The popularity of large-scale distributed applications, such as videoconferencing, multimedia dissemination, electronic stock exchange and distributed cooperative work, has grown with the availability of high-speed networks and the expansion of the Internet. The key property of this type of applications is the need to distribute data among multiple participants together with an application-specific quality of service needs. This fact makes scalable multicast protocols an essential underlying communication structure. Although there exist several studies investigating the traffic characteristics of unicast communication, multicast traffic has not been examined extensively in previous studies. It is well known that the aggregate traffic properties of …
The \Mathcal{H}_\Infty Model Matching Problem With One Degree Of Freedom Static State Feedback, Murat Akin, Ati̇lla Bi̇r
The \Mathcal{H}_\Infty Model Matching Problem With One Degree Of Freedom Static State Feedback, Murat Akin, Ati̇lla Bi̇r
Turkish Journal of Electrical Engineering and Computer Sciences
The aim of this paper is to develop a new approach for a solution of the continuous-time model matching problem by a static state feedback in the sense of \mathcal{H}_\infty optimality criterion by using Linear Matrix Inequalities (LMIs). The main contribution could briefly be described as to reformulate the model matching problem in LMI formulation, to present the solvability conditions and to give a design procedure for the one degree of freedom static state feedback control law. Finally, the results are applied to an example system.
New Approaches For On-Line Tuning Of The Linear Sliding Surface Slope In Sliding Mode Controllers, Sezai̇ Tokat, İbrahi̇m Eksi̇n, Müjde Güzelkaya
New Approaches For On-Line Tuning Of The Linear Sliding Surface Slope In Sliding Mode Controllers, Sezai̇ Tokat, İbrahi̇m Eksi̇n, Müjde Güzelkaya
Turkish Journal of Electrical Engineering and Computer Sciences
The main objective of this study is to propose new approaches for on-line tuning of the linear sliding surface slope in sliding mode controllers. The new approaches are developed for a class of second order systems on new coordinate axes, one of which is the classical sliding surface and the other one is naturally chosen to be orthogonal to it. The control input of the sliding mode control law is then modified accordingly by applying the Lyapunov stability condition. The adjustment of the linear sliding surface slope defined in the new coordinate axes is achieved by tuning a new parameter …
Improving The Security And Flexibility Of One-Time Passwords By Signature Chains, Kemal Biçakci, Nazi̇fe Baykal
Improving The Security And Flexibility Of One-Time Passwords By Signature Chains, Kemal Biçakci, Nazi̇fe Baykal
Turkish Journal of Electrical Engineering and Computer Sciences
While the classical attack of ``monitor the network and intercept the password'' can be avoided by advanced protocols like SSH, one-time passwords are still considered a viable alternative or a supplement for software authentication since they are the only ones that safeguard against attacks on insecure client machines. In this paper by using public-key techniques we present a method called signature chain alternative to Lamport's hash chain to improve security and flexibility of one-time passwords. Our proposition improves the security because first, like other public-key authentication protocols, the server and the user do not share a secret, thereby eliminating attacks …
Variation In Thickness Of Copper Films Deposited At Various Distances And Angles Using The Thermionic Vacuum Arc, Tamer Akan, Naci̇ Ekem
Variation In Thickness Of Copper Films Deposited At Various Distances And Angles Using The Thermionic Vacuum Arc, Tamer Akan, Naci̇ Ekem
Turkish Journal of Physics
The thermionic vacuum arc (TVA) is a new technique for the deposition of thin metallic films. Copper depositions were made on glass substrates placed at various distances and angles with respect to the TVA source. By measuring the thickness of the film on each substrate, the variation in the thickness as a function of the distance and angle with respect to the TVA source is investigated.
A Study Of Direct Two-Proton Transfer Reactions Using Optical Potential Model, A. K. A. R. Al-Farra
A Study Of Direct Two-Proton Transfer Reactions Using Optical Potential Model, A. K. A. R. Al-Farra
Turkish Journal of Physics
^{12}C, ^{26}Mg(^3He,n) reactions have been studied at high bombardment energy with evaluation of the differential cross sections to the ground and the first excited states evaluated in the framework of the exact finite-range Born approximation (DWBA) calculations using the optical model. With the constraint that bound-state interactions have a Thomas-Fermi spin orbit form, different formations of the bound-state wave functions are explored. The calculated angular distributions are found to be in a good agreement with the experimental data. The present DWBA predictions are normalized to give the best overall fits to the data. The extracted spectroscopic factors are reasonable.
First Principles Modeling Of Nanostructures, Serdar Öğüt
First Principles Modeling Of Nanostructures, Serdar Öğüt
Turkish Journal of Physics
Among the various theoretical tools for investigating microscopic material properties, ab initio (first principles) methods based on density functional theory and pseudopotentials have had a very good track record over the last two decades in terms of accuracy, reliability, and efficiency. The application of these methods to nanostructures to investigate their structural, electronic, and optical properties has, however, not been quite straightforward due to the large computational demand and new physics inherent in the nanometer and sub-nanometer size region. One particularly useful extension to overcome the computational demand imposed by localized nanostructures has been the introduction of methods based on …
Rough Singular Integrals Along Submanifolds Of Finite Type On Product Domains, Hussain Al-Qassem
Rough Singular Integrals Along Submanifolds Of Finite Type On Product Domains, Hussain Al-Qassem
Turkish Journal of Mathematics
We establish the L^p boundedness of singular integrals on product domains with rough kernels in L(log L)^2 and are supported by subvarieties.
Inhibition Studies Of A Few Organic Compounds And Their Condensation Products On The Corrosion Of Zinc In Hydrochloric Acid Medium, Shanthamma K. Rajappa, Thimmappa V. Venkatesha
Inhibition Studies Of A Few Organic Compounds And Their Condensation Products On The Corrosion Of Zinc In Hydrochloric Acid Medium, Shanthamma K. Rajappa, Thimmappa V. Venkatesha
Turkish Journal of Chemistry
The corrosive behavior of zinc in HCl solution containing various concentrations of glutaraldehyde GTD, glycine GLN, methionine MTN, and their condensation products formed between GTD + GLN (CP1) and GTD + MTN (CP2) was investigated. The corrosion-inhibitive action of these compounds on zinc metal was studied using chemical and electrochemical methods. The results showed that the compound CP2 is the best inhibitor and that its inhibition efficiency reaches 92.56% at 10^{-2} M in 0.05 M acid concentration. As an inhibitor, CP2 was found to have a predominant cathodic effect and its adsorption was confirmed with the Temkin isotherm. The effect …
Fiber Sums Of Genus 2 Lefschetz Fibrations, Denis Auroux
Fiber Sums Of Genus 2 Lefschetz Fibrations, Denis Auroux
Turkish Journal of Mathematics
Using the recent results of Siebert and Tian about the holomorphicity of genus 2 Lefschetz fibrations with irreducible singular fibers, we show that any genus 2 Lefschetz fibration becomes holomorphic after fiber sum with a holomorphic fibration.
Galois Symmetry On Floer Cohomology, Kenji Fukaya
Galois Symmetry On Floer Cohomology, Kenji Fukaya
Turkish Journal of Mathematics
In this article, we define an action of \hat{\Bbb Z} on the A_{\infty} category whose objects are rational Lagrangian submanifolds together with some other data. The group \hat{\Bbb Z} is a Galois group of the (universal) Novikov ring (field) over Laurent polynomial field. By mirror symmetry it will corresponds to the algebraic fundamental group of a punctured disk which parametrize the maximal degenerate family of the mirror complex manifold.
Adjunction Inequality And Coverings Of Stein Surfaces, Stefan Nemirovski
Adjunction Inequality And Coverings Of Stein Surfaces, Stefan Nemirovski
Turkish Journal of Mathematics
A stronger form of the adjunction inequality is proved for immersed real surfaces in non simply-connected Stein surfaces. The result is applied to the geometry of Stein domains and analytic continuation on complex surfaces.
Polyhedral Approximations Of Riemannian Manifolds, Anton Petrunin
Polyhedral Approximations Of Riemannian Manifolds, Anton Petrunin
Turkish Journal of Mathematics
I'm trying to understand which Riemannian manifolds can be Lipschitz approximated by polyhedral spaces of the same dimension with curvature bounded below. The necessary conditions I found consist of some special inequality for curvature at each point (the geometric curvature bound). This inequality is also sufficient condition for local approximation. I conjecture that it is also a sufficient condition for global approximation, and I can prove it if the curvature bound is positive. In general I can prove it only with the additional assumption that tangent bundle of the manifold is stably trivial.
Comparing Open Book And Heegaard Decompositions Of 3-Manifolds, J. Hyam Rubinstein
Comparing Open Book And Heegaard Decompositions Of 3-Manifolds, J. Hyam Rubinstein
Turkish Journal of Mathematics
We study the maximal value of the Euler characteristic of the pages of all open book decompositions of closed orientable 3-manifolds. In particular, we describe some examples where the minimal genus Heegaard splittings of such 3-manifolds give rise to open book decompositions and other examples where the simplest open book decomposition has larger maximal Euler characteristic of pages than the smallest genus Heegaard splittings. Also, special properties of the Heegaard splitting associated to an open book decomposition are given. Techniques of minimal surface theory and hyperbolic geometry are shown to be useful for such problems.