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 8971 - 9000 of 10317
Full-Text Articles in Physical Sciences and Mathematics
On L_{P}-Approximation By A Linear Combination Of A New Sequence Of Linear Positive Operators, P. N. Agrawal, Ali Jassim Mohammad
On L_{P}-Approximation By A Linear Combination Of A New Sequence Of Linear Positive Operators, P. N. Agrawal, Ali Jassim Mohammad
Turkish Journal of Mathematics
In the present paper, we study some direct results in L_{p} -approximation by a linear combination of a new sequence of linear positive operators. The error in the approximation is estimated in terms of the higher order integral modulus of smoothness using some properties of the Steklov means.
Pushouts Of Profinite Crossed Modules And Cat^1-Profinite Groups, Murat Alp, Özgün Gürmen
Pushouts Of Profinite Crossed Modules And Cat^1-Profinite Groups, Murat Alp, Özgün Gürmen
Turkish Journal of Mathematics
In this paper, we presented a brief review of crossed modules [7], cat^1-groups [6], pullback crossed modules [4], pullback cat^1-group [1], profinite crossed modules [5], cat^1-profinite groups [5], pullback profinite crossed modules [5], pullback cat^1-profinite groups [3]. We defined the pushout cat^1-profinite groups and gave the left adjoint constructions.
An Analytical Model For Calculating Bounds On Call Blocking Probabilities In Leo Satellite Networks, A. Hali̇m Zai̇m
An Analytical Model For Calculating Bounds On Call Blocking Probabilities In Leo Satellite Networks, A. Hali̇m Zai̇m
Turkish Journal of Electrical Engineering and Computer Sciences
We present an analytical model for calculating upper and lower bounds for call-blocking probabilities in a LEO satellite network that carries voice calls. The method is especially useful for large systems where calculation of call-blocking probabilities are too expensive. Our method calculates upper and lower bounds very easily and produces fairly accurate results.
Resonant Demagnetization Pwm Forward Converter, B. Bi̇lgi̇n, Işik Çadirci, R. Ergül, M. Ermi̇ş
Resonant Demagnetization Pwm Forward Converter, B. Bi̇lgi̇n, Işik Çadirci, R. Ergül, M. Ermi̇ş
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, a new approach to demagnetization process of a PWM forward converter (FC) is proposed. According to this approach, the demagnetization winding and diode of a conventional FC are removed, and an external capacitor is added in parallel with the secondary diode. This replacement changes the linear demagnetization process of a conventional FC into a resonant demagnetization process. The theoretical performance results of the proposed resonant demagnetization forward converter (RDFC) are compared with those of a conventional FC. A side by side comparison made between the two types of demagnetization strategies has shown that RDFC has some advantages …
Zero-Crossing Based Demodulation Of Minimum Shift Keying, Mi̇ne Kalkan, Feza Keresteci̇oğlu
Zero-Crossing Based Demodulation Of Minimum Shift Keying, Mi̇ne Kalkan, Feza Keresteci̇oğlu
Turkish Journal of Electrical Engineering and Computer Sciences
Minimum shift keying (MSK) modulation has features such as constant envelope, compact spectrum and good error performance, which are all desirable in many digital applications including mobile radio. Numerous receiver structures to demodulate MSK have been suggested, such as correlation receivers, differential detectors and frequency discriminators. MSK is a form of biphase keying and can be detected by a zero-crossing based phase demodulator which gives near optimum performance. In this paper, the bit error performance of a zero-crossing based coherent MSK demodulator is theoretically investigated and a closed-form expression for the bit error rate is derived. The results indicate that …
Design Of A Tem-Cell With Increased Usable Test Area, Kresimir Malaric, Juraj Bartolic
Design Of A Tem-Cell With Increased Usable Test Area, Kresimir Malaric, Juraj Bartolic
Turkish Journal of Electrical Engineering and Computer Sciences
Transversal electromagnetic mode cells (TEM-cells) are used for electromagnetic compatibility measurements (emission and immunity), and for biomedical applications. Over the years, higher and higher frequencies are being used, which demands smaller transmission structures in order to obtain the homogeneous field distribution due to resonance. Such resonance destroys the TEM field, introducing higher order modes. The goal was to design the TEM-cell for GSM frequencies that will have a larger area with a homogeneous field used for testing, while still obtaining the characteristic impedance. Commercial TEM-cells used for frequencies of 900 MHz have only 2 cm in height available for testing, …
A Digitally Controlled Drive System For Travelling-Wave Ultrasonic Motor, Güngör Bal
A Digitally Controlled Drive System For Travelling-Wave Ultrasonic Motor, Güngör Bal
Turkish Journal of Electrical Engineering and Computer Sciences
A digitally controlled drive system was implemented in this study to control the speed and direction of a travelling-wave ultrasonic motor. The drive system, based on a 2-phase voltage-fed high-frequency serial-resonant inverter, uses the mechanical resonant frequency of an ultrasonic motor. A TMS320F243 digital signal processor was used to control an ultrasonic motor drive system. The speed control of the ultrasonic motor was achieved with a driving frequency in the 41.3-43.3 kHz frequency range. The feasible evaluations of the proposed drive and control system were tested by experiments. Experimental results demonstrated that the proposed drive and control system is flexible …
Parametrically Tunable Audio Shelving And Equalizing Ladder Wave Digital Filters, S. A. Samad
Parametrically Tunable Audio Shelving And Equalizing Ladder Wave Digital Filters, S. A. Samad
Turkish Journal of Electrical Engineering and Computer Sciences
Parametrically tunable audio equalizers are conventionally realized using allpass digital filter networks. They consist of first-order shelving filters and second-order equalizing filters. In this paper, ladder wave digital filters (WDFs) with parametrically tunable coefficients are proposed as shelving and equalizing filters. Similar to the allpass realization, the transfer function power complementary property of WDFs is used to obtain efficient shelving and equalizing filters. However, unlike the allpass structures, the transfer function and the tunable parameters of the ladder WDF are derived from the analog filter equivalent of the digital shelving and equalizing filters. For the shelving WDF, the cut-off frequency …
A New Simulator For Hvdc/Ac Systems-Part I, Baktiar Zangeneh, Abbas Shoulaie
A New Simulator For Hvdc/Ac Systems-Part I, Baktiar Zangeneh, Abbas Shoulaie
Turkish Journal of Electrical Engineering and Computer Sciences
A simulator with optimal step time (SOST) has been designed to investigate Large HVdc/ac systems. The adequacy and robustness of the simulator will be demonstrated by showing some important applications relevant to operation, operational planning and medium-term planing. Some of the features of our SOST simulator are optimal step time algorithm, interpolation, chatter removal, MATLAB interface, unlimited size of ac system, and Farsi command that help model complex power electronic circuits, provide fast and accurate results. On account of its reduced calculation effort and deterministic execution time, optimal-step simulation is a prerequisite for real-time performance. However, when simulating electromagnetic-transients behavior, …
A New Simulator For Hvdc/Ac Systems-Part Ii, Baktiar Zangeneh, Abbas Shoulaie
A New Simulator For Hvdc/Ac Systems-Part Ii, Baktiar Zangeneh, Abbas Shoulaie
Turkish Journal of Electrical Engineering and Computer Sciences
This paper presents a performance comparison (the focus of numerical simulation) of traditional simulation (TCS,TSE) with an optimal step time simulator (SOST) for large HVdc systems.In SOST, a Detailed simulation of HVdc converter behavior has been modified to include the automatic selection of optimal integration steps, frequency-dependent effects of an ac system, ac system phase and magnitude dynamics of voltage (particularly weak ac systems), control assessment and temporary over-voltage consequences. SOST, via graphical interfaces,provides fast and accurate information of electromechanical and the electromagnetic-transients behavior of a large HVdc/HVac system.
Field Extensions Having The Unique Subfield Property, And G-Cogalois Extensions, Toma Albu
Field Extensions Having The Unique Subfield Property, And G-Cogalois Extensions, Toma Albu
Turkish Journal of Mathematics
We present a short proof, based on Cogalois Theory, of a result due to Acosta de Orozco and Vélez (1982, J. Number Theory 15, 388-405) characterizing separable simple radical field extensions with the unique subfield property, and prove that these extensions are precisely the simple G--Cogalois extensions with a cyclic Kneser group.
Ko-Groups Of Bounded Flag Manifolds, Yusuf Ci̇van
Ko-Groups Of Bounded Flag Manifolds, Yusuf Ci̇van
Turkish Journal of Mathematics
We exhibit an appropriate suspension of bounded flag manifolds as a wedge sum of Thom complexes of associated complex line bundles. We use the existence of such a splitting to assist our computation of real and complex K-groups. Moreover, we compute the Sq^2-homology of bounded flag manifolds to make use of relevant Atiyah-Hirzebruch spectral sequence of KO-theory.
\Theta-Euclidean L-Fuzzy Ideals Of Rings, Ayten Koç, Erol Balkanay
\Theta-Euclidean L-Fuzzy Ideals Of Rings, Ayten Koç, Erol Balkanay
Turkish Journal of Mathematics
The concept of fuzzy ideals is extended by introducing \theta -Euclidean L-fuzzy ideals in rings. In particular, some structural theorems for a \theta -Euclidean L-fuzzy ideal of R are proved.
Left Adjoint Of Pullback Cat^1- Profinite Groups, Murat Alp
Left Adjoint Of Pullback Cat^1- Profinite Groups, Murat Alp
Turkish Journal of Mathematics
In this paper, we present a brief review crossed modules \cite{whitehead}, cat^1-groups \cite{loday}, profinite crossed modules \cite{kortim}, cat^1-profinite groups \cite{kortim}, pullback profinite crossed modules \cite{kortim} and also the pullback cat^1- profinite groups \cite{hind}. We prove that the pulback cat^1-profinite group has a left adjoint which is the induced cat^1-group.
New Tensor Norms And Operator Ideals Associated To Interpolation Spaces Between Sequence Spaces, G. Castaneda, J. A. Lopez Molina, M. J. Rivera
New Tensor Norms And Operator Ideals Associated To Interpolation Spaces Between Sequence Spaces, G. Castaneda, J. A. Lopez Molina, M. J. Rivera
Turkish Journal of Mathematics
We introduce a wide class of tensor norms g_{\lambda,\rho} which are defined with the help of interpolation spaces between perfect sequence spaces defined by a general parameter real interpolation method. We also characterize the associated \lambda_{\rho}-nuclear and \lambda_{\rho}-integral operators.
Characterizations Of Artinian And Noetherian Gamma-Rings In Terms Of Fuzzy Ideals, Mehmet Ali̇ Öztürk, Mustafa Uçkun, Young Bae Jun
Characterizations Of Artinian And Noetherian Gamma-Rings In Terms Of Fuzzy Ideals, Mehmet Ali̇ Öztürk, Mustafa Uçkun, Young Bae Jun
Turkish Journal of Mathematics
Using fuzzy ideals, characterizations of Noetherian \Gamma-rings are given, and a condition for a \Gamma-ring to be Artinian is also given.
On Non-Existence Of Korovkin's Theorem In The Space Of L_{P}-Locally Integrable Functions, A. D. Gadjiev, Ertan İbi̇kli̇
On Non-Existence Of Korovkin's Theorem In The Space Of L_{P}-Locally Integrable Functions, A. D. Gadjiev, Ertan İbi̇kli̇
Turkish Journal of Mathematics
It is shown that a Korovkin-type theorem does not hold in the weighted space of L_{p}-locally integrable functions on the whole real axis.
Deformation Inequivalent Complex Conjugated Complex Structures And Applications, Viatcheslav Kharlamov, Viktor Kulikov
Deformation Inequivalent Complex Conjugated Complex Structures And Applications, Viatcheslav Kharlamov, Viktor Kulikov
Turkish Journal of Mathematics
We start from a short summary of our principal result from [KK]: an example of a complex algebraic surface which is not deformation equivalent to its complex conjugate and which, moreover, has no homeomorphisms reversing the canonical class. Then, we generalize this result to higher dimensions and construct several series of higher dimensional compact complex manifolds having no homeomorphisms reversing the canonical class. After that, we resume and broaden the applications given in [KK] and [KK2], in particular, as a new application, we propose examples of (deformation) non equivalent symplectic structures with opposite canonical classes.
Combinatorial Patchworking Of Real Pseudo-Holomorphic Curves, Ilia Itenberg, Eugenii Shustin
Combinatorial Patchworking Of Real Pseudo-Holomorphic Curves, Ilia Itenberg, Eugenii Shustin
Turkish Journal of Mathematics
The Viro method of construction of real algebraic varieties with prescribed topology uses convex subdivisions of Newton polyhedra. We show that in the case of arbitrary (not necessarily convex) subdivisions of polygons corresponding to C P^2 and rational ruled surfaces \Sigma_a, a \geq 0 the Viro method produces pseudo-holomorphic curves. The version of the Viro method discussed in the paper also gives a possibility to construct singular pseudo-holomorphic curves by gluing singular algebraic curves whose collections of singularities do not permit to glue these curves in the framework of the standard Viro method. As an application, we construct a series …
On 1-Point Gromov-Witten Invariants Of The Hilbert Schemes Of Points On Surfaces, Wei-Ping Li, Zhenbo Qin
On 1-Point Gromov-Witten Invariants Of The Hilbert Schemes Of Points On Surfaces, Wei-Ping Li, Zhenbo Qin
Turkish Journal of Mathematics
We compute certain 1-point genus-0 Gromov-Witten invariants of the Hilbert scheme of points on a simply-connected smooth projective surface.
Evidence For A Conjecture Of Pandharipande, Jim Bryan
Evidence For A Conjecture Of Pandharipande, Jim Bryan
Turkish Journal of Mathematics
In his paper ``Hodge integrals and degenerate contributions'', Pandharipande studied the relationship between the enumerative geometry of certain 3-folds and the Gromov-Witten invariants. In some good cases, enumerative invariants (which are manifestly integers) can be expressed as a rational combination of Gromov-Witten invariants. Pandharipande speculated that the same combination of invariants should yield integers even when they do not have any enumerative significance on the 3-fold. In the case when the 3-fold is the product of a complex surface and an elliptic curve, Pandharipande has computed this combination of invariants on the 3-fold in terms of the Gromov-Witten invariants of …
Minimality Of Certain Normal Connected Sums, Tian-Jun Li, Andras I. Stipsicz
Minimality Of Certain Normal Connected Sums, Tian-Jun Li, Andras I. Stipsicz
Turkish Journal of Mathematics
We show that the normal connected sum of two minimal symplectic 4-manifolds (neither of them rational or ruled) is a minimal symplectic 4-manifold. In the proof we use a symplectic sum formula for Gromov-Witten invariants.
Variations On Fintushel-Stern Knot Surgery On 4-Manifolds, Selman Akbulut
Variations On Fintushel-Stern Knot Surgery On 4-Manifolds, Selman Akbulut
Turkish Journal of Mathematics
We discuss some consequences Fintushel-Stern `knot surgery' operation coming from its handlebody description. We give some generalizations of this operation and give a counterexample to their conjecture.
Braids And Symplectic Four-Manifolds With Abelian Fundamental Group, Paul Seidel
Braids And Symplectic Four-Manifolds With Abelian Fundamental Group, Paul Seidel
Turkish Journal of Mathematics
We explain how a version of Floer homology can be used as an invariant of symplectic manifolds with b_1>0. As a concrete example, we look at four-manifolds produced from braids by a surgery construction. The outcome shows that the invariant is nontrivial; however, it is an open question whether it is stronger than the known ones.
Low-Dimensional Homology Groups Of Mapping Class Groups: A Survey, Mustafa Korkmaz
Low-Dimensional Homology Groups Of Mapping Class Groups: A Survey, Mustafa Korkmaz
Turkish Journal of Mathematics
In this survey paper, we give a complete list of known results on the first and the second homology groups of surface mapping class groups. Some known results on higher (co) homology are also mentioned.
Gauge Theory And Stein Fillings Of Certain 3-Manifolds, Andras I. Stipsicz
Gauge Theory And Stein Fillings Of Certain 3-Manifolds, Andras I. Stipsicz
Turkish Journal of Mathematics
In the following we show that a Stein filling S of the 3-torus T^3 is homeomorphic to D^2 \times T^2. In the proof we also show that if S is Stein and \partial S is diffeomorphic to the Seifert fibered 3-manifold -\Sigma (2,3,11) then b_1(S)=0 and Q_S=H. Similar results are obtained for the Poincaré homology sphere \pm \Sigma (2,3,5); in studying these fillings we apply recent gauge theoretic results, and prove our theorems by determining certain Seiberg-Witten invariants.
Obituary Prof. Dr. Kâzım Ergi̇n [21 May 1915-24 November 2002] By, Tuncay Taymaz
Obituary Prof. Dr. Kâzım Ergi̇n [21 May 1915-24 November 2002] By, Tuncay Taymaz
Turkish Journal of Earth Sciences
No abstract provided.
Tertiary Terrestrial To Shallow Marine Deposition In Central Anatolia: A Palynological Approach, Funda Akgün, Erhan Akay, Burhan Erdoğan
Tertiary Terrestrial To Shallow Marine Deposition In Central Anatolia: A Palynological Approach, Funda Akgün, Erhan Akay, Burhan Erdoğan
Turkish Journal of Earth Sciences
In central Turkey the Çankırı Basin developed between the Kırşehir and Sakarya continents as a collisional basin during the Tertiary. Along the southern border, between Yozgat and Yerköy, the basin fill predominantly comprises continental and shallow marine facies, and overlies the Late Cretaceous Kırşehir Block unconformably. The Yoncalı formation (shallow marine sandstones, shales and limestone lenses), the İncik formation (terrestrial conglomerates and sandstones) and the Bayat formation (subaerial lavas and pyroclastic rocks) are Middle to Late Eocene in age and grade laterally and vertically into each other. These units are unconformably overlain by a Middle Miocene continental sequence that is …
Geology Of The Ören And Surrounding Areas, Sw Anatolia, Ömer Feyzi̇ Gürer, Yücel Yilmaz
Geology Of The Ören And Surrounding Areas, Sw Anatolia, Ömer Feyzi̇ Gürer, Yücel Yilmaz
Turkish Journal of Earth Sciences
On the Lycian Nappes of SW Anatolia, Neogene basins developed along two different trends in different periods. NNE-trending basins formed during the Early-Middle Miocene period as exemplified by the Ören and Yatağan grabens. These graben fills consist of three distinct rock units. At the base are (1) coarse clastics, sourced from elevated areas adjacent to the basin-bounding faults. These are linear river-valley fills. They give way upward to (2) alternating coal-bearing sandstone and limestone as the graben valleys were gradually widened, and the surrounding mountains were reduced by erosion. Finally, lake environment formed, invading the region during the advanced stage …
Resistivity Distribution In The Gediz Graben And Its Implications For Crustal Structure, Aysan Gürer, Alaatti̇n Pi̇nçe, Ömer Feyzi̇ Gürer, O. Meti̇n İlkişik
Resistivity Distribution In The Gediz Graben And Its Implications For Crustal Structure, Aysan Gürer, Alaatti̇n Pi̇nçe, Ömer Feyzi̇ Gürer, O. Meti̇n İlkişik
Turkish Journal of Earth Sciences
Preliminary results of resistivity distribution in the crust around the Gediz graben by the magnetotelluric (MT) measurements along two 73- and 16-km-long MT profiles (M1 and profile M2) are presented. Bostick depth transformation of the resistivity component of the MT data denoted a conductive zone at a depth of ~ 10 km. This zone may be related to crustal extension and high regional heat flow (50% higher than the world average). Preliminary interpretation based on one dimensional (1D) inversion result show that the thickness of sediments over the resistive basement changes from 950-3800 m along the profile M1. The relations …