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Articles 5431 - 5460 of 10319
Full-Text Articles in Physical Sciences and Mathematics
Short-Term Load Forecasting Without Meteorological Data Using Ai-Based Structures, İdi̇l Işikli Esener, Tolga Yüksel, Mehmet Kurban
Short-Term Load Forecasting Without Meteorological Data Using Ai-Based Structures, İdi̇l Işikli Esener, Tolga Yüksel, Mehmet Kurban
Turkish Journal of Electrical Engineering and Computer Sciences
STLF is used in making decisions about economical power generation capacity, fuel purchasing, safety assessment, and power system planning in order to have economical power conditions. In this study, Turkey's 24-hour-ahead load forecasting without meteorological data is studied. ANN, wavelet transform and ANN, wavelet transform and RBF NN, and EMD and RBF NN structures are used in STLF procedures. Local holidays' historical load data are changed into data with normal day characteristics, and the estimation results of these days are not included in error computation. To obtain more accurate results, a regulation on forecasted loads is proposed. Regulated and unregulated …
An Intelligence-Based Islanding Detection Method Using Dwt And Ann, Mehrdad Heidari, Ghodratollah Seifossadat, Morteza Razaz
An Intelligence-Based Islanding Detection Method Using Dwt And Ann, Mehrdad Heidari, Ghodratollah Seifossadat, Morteza Razaz
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, a new method based on artificial neural network (ANN) and discrete wavelet transform (DWT) is proposed for electrical islanding detection. Transient signals produced during an event are used in the proposed method. ANN is trained to classify the transient events as islanding and nonislanding. The required features for classifying are extracted through DWT of voltage and current transient signals. The proposed method is then simulated on a medium voltage distribution system of CIGRE with 2 kinds of DGs. Results show that this method can detect electrical islands more rapidly and accurately.
Continuous-Time Hopfield Neural Network-Based Optimized Solution To 2-Channel Allocation Problem, Zekeri̇ya Uykan
Continuous-Time Hopfield Neural Network-Based Optimized Solution To 2-Channel Allocation Problem, Zekeri̇ya Uykan
Turkish Journal of Electrical Engineering and Computer Sciences
The channel allocation problem in cellular radio systems is NP-complete, and thus its general solution is not known for even the 2-channel case. It is well known that the link gain system matrix (or received-signal power system matrix) of the radio network is (and may be highly) asymmetric, and that as the Hopfield neural network is applied to optimization problems, its weight matrix should be symmetric. The main contribution of this paper is as follows: turning the channel allocation problem into a maxCut graph partitioning problem, we propose a simple and effective continuous-time Hopfield neural network-based solution by determining its …
On The Capacitance Of Crystalline Silicon Solar Cells In Steady State, Fabe Idrissa Barro, Moustapha Sane, Bernard Zouma
On The Capacitance Of Crystalline Silicon Solar Cells In Steady State, Fabe Idrissa Barro, Moustapha Sane, Bernard Zouma
Turkish Journal of Physics
In this work, an analytical approach is presented for modeling the capacitance of crystalline silicon solar cells. Based on a one-dimensional modeling of the cell, the excess minority carrier density, the photovoltage, and the capacitance are calculated. The motivation of this work are two-fold: to show base doping density and illumination effects on the capacitance of silicon solar cells, and to propose a determination technique for both dark capacitance and base doping density from C-V characteristics.
Evaluation Of The Global Solar Irradiance In The Vhembe District Of Limpopo Province, South Africa, Using Different Theoretical Modelsevaluation Of The Global Solar Irradiance In The Vhembe District Of Limpopo Province, South Africa, Using Different Theoretical Models, Tshimangadzo Sophie Mulaudzi, Nnditshedzeni Eric Maluta, Vaith Sankaran
Evaluation Of The Global Solar Irradiance In The Vhembe District Of Limpopo Province, South Africa, Using Different Theoretical Modelsevaluation Of The Global Solar Irradiance In The Vhembe District Of Limpopo Province, South Africa, Using Different Theoretical Models, Tshimangadzo Sophie Mulaudzi, Nnditshedzeni Eric Maluta, Vaith Sankaran
Turkish Journal of Physics
An attempt has been made to employ three different theoretical models for the determination of global solar radiation for the climate conditions of the Vhembe district of Limpopo Province in South Africa. The models are: 1) the Angstrom linear-based model, 2) the Hargreaves and Samani (temperature-based) model, and 3) the Garcia model. These models require the following meteorological data inputs: temperature, sunshine hours, and global solar irradiance on the horizontal surface. The regression coefficients from our previous study were also employed in the calculations. A 4-year (2007--2010) global solar irradiance and temperature data set from the Agricultural Research Council and …
Nanocrystalline Nio Structure: Preferred Oriented Growthnanocrystalline Nio Structure: Preferred Oriented Growth, Ali Rahmati, Soheila Mardani
Nanocrystalline Nio Structure: Preferred Oriented Growthnanocrystalline Nio Structure: Preferred Oriented Growth, Ali Rahmati, Soheila Mardani
Turkish Journal of Physics
Nickel oxide (NiO) nanostructures were deposited on Si (100), potassium bromide (KBr), and glass slide substrates at room temperature by the evaporation technique. The prepared samples were annealed at temperatures of 400 $^{\circ}$C and 600 $^{\circ}$C in air atmosphere. The structure, morphology, crystalline phase, optical properties, and chemical bonding of nanocrystalline nickel oxide were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), UV-visible absorption spectrum, and FT-IR spectroscopy. XRD results and SEM images showed that nickel oxide nanoparticles have preferred orientation with uniform size distribution. The as-deposited films showed preferred orientation (texture) growth. As the films were annealed, the …
External Magnetic Field Effect On Bifacial Silicon Solar Cell''S Electric Power And Conversion Efficiencyexternal Magnetic Field Effect On Bifacial Silicon Solar Cell''S Electric Power And Conversion Efficiency, Issa Zerbo, Martial Zoungrana, Idrissa Sourabie, Adama Ouedraogo, Bernard Zouma, Dieudonne Joseph Bathiebo
External Magnetic Field Effect On Bifacial Silicon Solar Cell''S Electric Power And Conversion Efficiencyexternal Magnetic Field Effect On Bifacial Silicon Solar Cell''S Electric Power And Conversion Efficiency, Issa Zerbo, Martial Zoungrana, Idrissa Sourabie, Adama Ouedraogo, Bernard Zouma, Dieudonne Joseph Bathiebo
Turkish Journal of Physics
This article presents a modelling study of external magnetic field effect on a bifacial silicon solar cell's electric power and conversion efficiency. After the resolution of the magnetotransport equation and continuity equation of excess minority carriers, we calculate the photocurrent density and the photovoltage and then we deduce the solar cell's electric power before discussing the influence of the magnetic field on those electrical parameters. Using the electric power curves versus junction dynamic velocity we determine the maximum electric power, the operating point of the solar cell, and the conversion efficiency according to magnetic field intensity. The numerical data show …
Origin, Evolution, And Tectonic Setting Of The Eastern Part Of The Mexican Volcanic Belt And Comparison With The Central American Volcanic Arc From Conventional Multielement Normalized And New Multidimensional Discrimination Diagrams And Discordancy And Significance Tests, Surendra P. Verma
Turkish Journal of Earth Sciences
If both the Mexican Volcanic Belt (MVB) and the Central American Volcanic Arc (CAVA) have been related to the subduction of the Cocos plate beneath the North American and Caribbean plates, respectively, their magmas, and especially the less evolved basic varieties, should show considerable similarities. The conventional multielement normalized diagrams indicate more complex petrogenetic processes for the MVB than the CAVA. Forty-five statistically coherent tectonomagmatic discrimination diagrams were used to infer the tectonic setting of the controversial geological subprovince of the eastern part of the MVB (E-MVB). Basic rocks from the E-MVB indicated a continental rift setting, whereas the intermediate …
Empirical M X-Ray Production Cross Sections For Heavy Elements By Proton Impact Within Z-Dependence Analysisempirical M X-Ray Production Cross Sections For Heavy Elements By Proton Impact Within Z-Dependence Analysis, Bahri Deghfel, Farid Khalfallah, Abdelhalim Kahoul, Mohammed Nekkab
Empirical M X-Ray Production Cross Sections For Heavy Elements By Proton Impact Within Z-Dependence Analysisempirical M X-Ray Production Cross Sections For Heavy Elements By Proton Impact Within Z-Dependence Analysis, Bahri Deghfel, Farid Khalfallah, Abdelhalim Kahoul, Mohammed Nekkab
Turkish Journal of Physics
New empirical M-shell X-ray production cross sections have been deduced by introducing the dependence of the universal trend of the experimental data on the atomic number of the target, noted as "Z-dependence" for semiempirical cross sections in our previous work. For this effect, the updated experimental data (from 1980 to 2009) are used to calculate the empirical cross sections for heavy elements with 60 $\le $ Z $\le $ 90 by proton impact. Finally, a comparison is made between the deduced results and other earlier works.
Stability Of Perturbed Dynamic System On Time Scales With Initial Time Difference, Coşkun Yakar, Bülent Oğur
Stability Of Perturbed Dynamic System On Time Scales With Initial Time Difference, Coşkun Yakar, Bülent Oğur
Turkish Journal of Mathematics
The behavior of solutions of a perturbed dynamic system with respect to an original unperturbed dynamic system, which have initial time difference, are investigated on arbitrary time scales. Notions of stability, asymptotic stability, and instability with initial time difference are introduced. Sufficient conditions of stability properties are given with the help of Lyapunov-like functions.
Rings With Finite Ding Homological Dimensions, Chunxia Zhang, Zhongkui Liu
Rings With Finite Ding Homological Dimensions, Chunxia Zhang, Zhongkui Liu
Turkish Journal of Mathematics
In this paper, we study Ding homological dimensions of complexes. Special attention is paid to the dimensions of homologically bounded complexes that have nice functorial descriptions. These results are applied to give new characterizations of rings R such that l.Ggldim(R) < \infty and quasi-Frobenius rings.
Balanced Pair Algorithm For A Class Of Cubic Substitutions, Tarek Sellami
Balanced Pair Algorithm For A Class Of Cubic Substitutions, Tarek Sellami
Turkish Journal of Mathematics
In this article we introduce the balanced pair algorithm associated with 2 unimodular Pisot substitutions having the same incidence matrix. We are interested in beta-substitution related to the polynomial x^3 - ax^2 - bx-1 for a \geq b \geq 1. Applying the balanced pair algorithm to these substitutions, we obtain a general formula for the associated intersection substitution.
Arithmetical Rank Of The Edge Ideals Of Some N-Cyclic Graphs With A Common Edge, Guangjun Zhu, Feng Shi, Yan Gu
Arithmetical Rank Of The Edge Ideals Of Some N-Cyclic Graphs With A Common Edge, Guangjun Zhu, Feng Shi, Yan Gu
Turkish Journal of Mathematics
In this paper, we present some lower bounds and upper bounds on the arithmetical rank of the edge ideals of some n-cyclic graphs with a common edge. For some special n-cyclic graphs with a common edge, we prove that the arithmetical rank equals the projective dimension of the corresponding quotient ring.
Zero Triple Product Determined Generalized Matrix Algebras, Dong Han
Zero Triple Product Determined Generalized Matrix Algebras, Dong Han
Turkish Journal of Mathematics
In this paper, we prove that the generalized matrix algebra G = \left[ A M N B \right] is a zero triple product (resp. zero Jordan triple product) determined if and only if A and B are zero triple products (resp. zero Jordan triple products) determined under certain conditions. Then the main results are applied to triangular algebras and full matrix algebras.
Coextended Weak Entwining Structures, José Nicanor Alonso Álvarez, José Manuel Fernandez Vilaboa, Ramón González Rodríguez
Coextended Weak Entwining Structures, José Nicanor Alonso Álvarez, José Manuel Fernandez Vilaboa, Ramón González Rodríguez
Turkish Journal of Mathematics
In this paper, we formulate the definition of coextended weak entwining structure in a strict monoidal category with equalizers. For a coextended weak entwining structure (A,D,\psi,\alpha), we introduce the notions of weak (D,\alpha)-cleft extension and weak (D,\alpha)-Galois extension (with normal basis), proving that weak (D,\alpha)-Galois extensions with normal basis are equivalent to weak (D,\alpha)-cleft extensions.
A Decomposition Of Transferable Utility Games: Structure Of Transferable Utility Games, Ayşe Mutlu Derya
A Decomposition Of Transferable Utility Games: Structure Of Transferable Utility Games, Ayşe Mutlu Derya
Turkish Journal of Mathematics
We define a decomposition of transferable utility games based on shifting the worth of the grand coalition so that the associated game has a nonempty core. We classify the set of all transferable utility games based on that decomposition and analyze their structure. Using the decomposition and the notion of minimal balanced collections, we give a set of necessary and sufficient conditions for a transferable utility game to have a singleton core.
Companion Inequalities To Ostrowski--Grüss Type Inequality And Applications, Khalid Mahmood Awan, Josip Pecaric, Mihaela Ribicic Penava
Companion Inequalities To Ostrowski--Grüss Type Inequality And Applications, Khalid Mahmood Awan, Josip Pecaric, Mihaela Ribicic Penava
Turkish Journal of Mathematics
The aim of this paper is to give some companion inequalities to the Ostrowski-Grüss type inequality for n-time differentiable absolutely continuous functions by using recently obtained bounds for the Chebyshev functional.
Spreading Speeds In A Lattice Differential Equation With Distributed Delay, Huiling Niu
Spreading Speeds In A Lattice Differential Equation With Distributed Delay, Huiling Niu
Turkish Journal of Mathematics
This paper studies the spreading speed for a lattice differential equation with infinite distributed delay and we find that the spreading speed coincides with the minimal wave speed of traveling waves. Here the model has been proposed to describe a single species living in a 1D patch environment with infinite number of patches connected locally by diffusion.
The Geometry Of Hemi-Slant Submanifolds Of A Locally Product Riemannian Manifold, Hakan Mete Taştan, Fatma Özdemi̇r
The Geometry Of Hemi-Slant Submanifolds Of A Locally Product Riemannian Manifold, Hakan Mete Taştan, Fatma Özdemi̇r
Turkish Journal of Mathematics
In the present paper, we study hemi-slant submanifolds of a locally product Riemannian manifold. We prove that the anti-invariant distribution involved in the definition of hemi-slant submanifold is integrable and give some applications of this result. We get a necessary and sufficient condition for a proper hemi-slant submanifold to be a hemi-slant product. We also study these types of submanifolds with parallel canonical structures. Moreover, we give two characterization theorems for the totally umbilical proper hemi-slant submanifolds. Finally, we obtain a basic inequality involving Ricci curvature and the squared mean curvature of a hemi-slant submanifold of a certain type of …
The Fundamental Theorems Of Algebroid Functions On Annuli, Yang Tan, Qingcai Zhang
The Fundamental Theorems Of Algebroid Functions On Annuli, Yang Tan, Qingcai Zhang
Turkish Journal of Mathematics
An extension of Nevanlinna value distribution theory for algebroid functions on annuli is proposed. The main characteristics are one-parameter and possess the same properties as in the classical case. Analogs of the Cartan theorem, the first fundamental theorem, the second fundamental theorem, deficient values, and the uniqueness of algebroid functions on annuli are proved.
Almost Analytic Forms With Respect To A Quadratic Endomorphism And Their Cohomology, Mircea Crasmareanu, Cristian Ida
Almost Analytic Forms With Respect To A Quadratic Endomorphism And Their Cohomology, Mircea Crasmareanu, Cristian Ida
Turkish Journal of Mathematics
The goal of this paper is to consider the notion of almost analytic form in a unifying setting for both almost complex and almost paracomplex geometries. We use a global formalism, which yields, in addition to generalizations of the main results of the previously known almost complex case, a relationship with the Frölicher-Nijenhuis theory. A cohomology of almost analytic forms is also introduced and studied as well as deformations of almost analytic forms with pairs of almost analytic functions.
On Some Classes Of $3$-Dimensional Generalized $ (\Kappa ,\Mu )$-Contact Metric Manifolds, Ahmet Yildiz, Uday Chand De, Azi̇me Çeti̇nkaya
On Some Classes Of $3$-Dimensional Generalized $ (\Kappa ,\Mu )$-Contact Metric Manifolds, Ahmet Yildiz, Uday Chand De, Azi̇me Çeti̇nkaya
Turkish Journal of Mathematics
The object of the present paper is to obtain a necessary and sufficient condition for a $3$-dimensional generalized $(\kappa ,\mu )$-contact metric manifold to be locally $\phi $-symmetric in the sense of Takahashi and the condition is verified by an example. Next we characterize a $3$-dimensional generalized $(\kappa ,\mu )$-contact metric manifold satisfying certain curvature conditions on the concircular curvature tensor. Finally, we construct an example of a generalized $(\kappa,\mu)$-contact metric manifold to verify Theorem $1$ of our paper.
Regular Poles For The P-Adic Group $Gsp_4$-Ii, Yusuf Danişman
Regular Poles For The P-Adic Group $Gsp_4$-Ii, Yusuf Danişman
Turkish Journal of Mathematics
We compute the regular poles of the L-factors of the admissible and irreducible representations of the group $GSp_4$, which admit a nonsplit Bessel functional and have a Jacquet module length of 3 with respect to the unipotent radical of the Siegel parabolic, over a non-Archimedean local field of odd characteristic. We also compute the $L$-factors of the generic representations of $GSp_4$.
Od-Characterization Of Some Alternating Groups, Shitian Liu
Od-Characterization Of Some Alternating Groups, Shitian Liu
Turkish Journal of Mathematics
Let $G$ be a finite group. Moghaddamfar et al. defined prime graph $\Gamma(G)$ of group $G$ as follows. The vertices of $\Gamma(G)$ are the primes dividing the order of $G$ and two distinct vertices $p,q$ are joined by an edge, denoted by $p\sim q$, if there is an element in $G$ of order $pq$. Assume $ G =p_{1}^{\alpha_{1}}\cdots p_{k}^{\alpha_{k}}$ with $P_{1}$ <$\cdots$&\lt;$p_{k}$ and nature numbers $\alpha_{i}$ with $i=1,2,\cdots,k$. For $p\in\pi(G)$, let the degree of $p$ be $\deg(p)= \{q\in\pi(G)\mid q\sim p\} $, and $D(G)=(\deg(p_{1}), \deg(p_{2}), \cdots, \deg(p_{k}))$. Denote by $\pi(G)$ the set of prime divisor of $ G $. Let $GK(G)$ be the graph with vertex set $\pi(G)$ such that two primes $p$ and $q$ in $\pi(G)$ are joined by an edge if $G$ has an element of order $p\cdot q$. We set $s(G)$ to denote the number of connected components of the prime graph $GK(G)$. Some authors proved some groups are $OD$-characterizable with $s(G)\geq2$. Then for $s(G)=1$, what is the influence of $OD$ on the structure of groups? We knew that the alternating groups $A_{p+3}$, where $7\neq p\in\pi(100!)$, $A_{130}$ and $A_{140}$ are $OD$-characterizable. Therefore, we naturally ask the following question: if $s(G)=1$, then is there a group $OD$-characterizable? In this note, we give a characterization of $A_{p+3}$ except $A_{10}$ with $s(A_{p+3})=1$, by $OD$, which gives a positive answer to Moghaddamfar and Rahbariyan's conjecture.
Notes On Magnetic Curves In 3d Semi-Riemannian Manifolds, Zehra Özdemi̇r, İsmai̇l Gök, Yusuf Yayli, Fai̇k Nejat Ekmekci̇
Notes On Magnetic Curves In 3d Semi-Riemannian Manifolds, Zehra Özdemi̇r, İsmai̇l Gök, Yusuf Yayli, Fai̇k Nejat Ekmekci̇
Turkish Journal of Mathematics
A magnetic field is defined by the property that its divergence is zero in three-dimensional semi-Riemannian manifolds. Each magnetic field generates a magnetic flow whose trajectories are curves $\gamma $, called magnetic curves. In this paper, we investigate the effect of magnetic fields on the moving particle trajectories by variational approach to the magnetic flow associated with the Killing magnetic field on three-dimensional semi-Riemannian manifolds. We then investigate the trajectories of these magnetic fields and give some characterizations and examples of these curves.
Stability In A Job Market With Linearly Increasing Valuations And Quota System, Yasir Ali
Stability In A Job Market With Linearly Increasing Valuations And Quota System, Yasir Ali
Turkish Journal of Mathematics
We consider a job market in which preferences of players are represented by linearly increasing valuations. The set of players is divided into two disjoint subsets: a set of workers and a set of firms. The set of workers is further divided into subsets, which represent different categories or classes in everyday life. We consider that firms have vacant posts for all such categories. Each worker wants a job for a category to which he/she belongs. Firms have freedom to hire more than one worker from any category. A worker can work in only one category for at most one …
Invariant Distributions And Holomorphic Vector Fields In Paracontact Geometry, Mircea Crasmareanu, Laurian Ioan Piscoran
Invariant Distributions And Holomorphic Vector Fields In Paracontact Geometry, Mircea Crasmareanu, Laurian Ioan Piscoran
Turkish Journal of Mathematics
Having as a model the metric contact case of V. Brînzănescu; R. Slobodeanu, we study two similar subjects in the paracontact (metric) geometry: a) distributions that are invariant with respect to the structure endomorphism $\varphi $; b) the class of vector fields of holomorphic type. As examples we consider both the $3$-dimensional case and the general dimensional case through a Heisenberg-type structure inspired also by contact geometry.
Stability Of Compact Ricci Solitons Under Ricci Flow, Mina Vaghef, Asadollah Razavi
Stability Of Compact Ricci Solitons Under Ricci Flow, Mina Vaghef, Asadollah Razavi
Turkish Journal of Mathematics
In this paper we establish stability results for Ricci solitons under the Ricci flow, i.e. small perturbations of the Ricci soliton result in small variations in the solution under Ricci flow.
A Note On M-Embedded Subgroups Of Finite Groups, Juping Tang, Long Miao
A Note On M-Embedded Subgroups Of Finite Groups, Juping Tang, Long Miao
Turkish Journal of Mathematics
Let $A$ be a subgroup of $G$. $A$ is m-embedded in $G$ if $G$ has a subnormal subgroup $T$ and a $\{1\leq G\}$-embedded subgroup $C$ such that $G=AT$ and $T\cap A\leq C\leq A$. In this paper, we study the structure of finite groups by using m-embedded subgroups and obtain some new results about $p$-supersolvability and $p$-nilpotency of finite groups. \vs{-1mm}
Approximate Duals And Nearly Parseval Frames, Morteza Mirzaee Azandaryani
Approximate Duals And Nearly Parseval Frames, Morteza Mirzaee Azandaryani
Turkish Journal of Mathematics
In this paper we introduce approximate duality of g-frames in Hilbert $C^\ast$-modules and we show that approximate duals of g-frames in Hilbert $C^\ast$-modules share many useful properties with those in Hilbert spaces. Moreover, we obtain some new results for approximate duality of frames and g-frames in Hilbert spaces; in particular, we consider approximate duals of $\varepsilon$-nearly Parseval and $\varepsilon$-close frames.