Browsing FEF  Makale Koleksiyonu  Matematik Bölümü / Department of Mathematics by Author "Işık Üniversitesi, Fen Edebiyat Fakültesi, Matematik Bölümü"
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Adaptive convolution kernel for artificial neural networks
Tek, Faik Boray; Çam, İlker; Karlı, Deniz (Academic Press Inc., 202102)Many deep neural networks are built by using stacked convolutional layers of fixed and single size (often 3 × 3) kernels. This paper describes a method for learning the size of convolutional kernels to provide varying size ... 
Algebraic connectivity and degree sequences of trees
Bıyıkoğlu, Türker; Leydold, Josef (Elsevier Science Inc, 20090115)We investigate the structure of trees that have minimal algebraic connectivity among all trees with a given degree sequence. We show that such trees are caterpillars and that the vertex degrees are nondecreasing on every ... 
Amplitude modulation of nonlinear waves in a fluidfilled tapered elastic tube
Bakırtaş, İlkay; Demiray, Hilmi (Elsevier Science Inc, 20040715)In the present work, treating the arteries as a tapered, thin walled, long and circularly conical prestressed elastic tube and using the reductive perturbation method, we have studied the amplitude modulation of nonlinear ... 
Amplitude modulation of nonlinear waves in a fluidfilled tapered elastic tube
Demiray, Hilmi (WileyV C H Verlag, 2003)In the present work, treating the arteries as a tapered, thin walled, long, and circularly conical prestressed elastic tube and using the reductive perturbation method, we have studied the amplitude modulation of nonlinear ... 
Amplitude modulation of nonlinear waves in fluidfilled tapered tubes
Bakırtaş, İlkay; Demiray, Hilmi (Consultants Bureau, 200312)We study the modulation of nonlinear waves in fluidfilled prestressed tapered tubes. For this, we obtain the nonlinear dynamical equations of motion of a prestressed tapered tube filled with an incompressible inviscid ... 
An analysis of higher order terms for ionacoustic waves by use of the modified Poincar,LighthillKuo method
Demiray, Hilmi (Springer India, 201510)In this work, by utilizing the modified Poincar,LighthillKuo (PLK) method, we studied the propagation of weakly nonlinear waves in a collisionless cold plasma and obtained the governing evolution equations of various ... 
Analysis of periodic and solitary waves in a magnetosonic quantum dusty plasma
Demiray, Hilmi; Abdikian, Alireza (Springer, 202106)The propagation of nonlinear magnetosonic waves in electron–ion–dust (complex) plasmas has been studied by considering the effects of Bohm potential in the presence of an external magnetic field. By using the quantum ... 
Analytical approximate solutions for nonplanar Burgers equations by weighted residual method
Demiray, Hilmi; ElZahar, Essam Roshdy (Elsevier B.V., 20200813)In this work, analytical approximate progressive wave solutions for the generalized form of the nonplanar KdVBurgers (KdVB) and mKdVBurgers (mKdVB) equations are presented and the results are discussed. Motivated with ... 
Analytical solution for nonplanar waves in a plasma with qnonextensive nonthermal velocity distribution:Weighted residual method
Demiray, Hilmi (Elsevier Ltd, 202001)The basic nonlinear equations describing the dynamics of a two component plasma consisting of cold positive ions and electrons obeying hybrid q nonextensive nonthermal velocity distribution are examined in the ... 
An analytical solution to the dissipative nonlinear Schrodinger equation
Demiray, Hilmi (Elsevier Science, 20031220)Motivated with a solitary wave type of solution to the nonlinear Schrodinger (NLS) equation, in this work we shall seek a travelling wave solution to the dissipative NLS equation by use of the hyperbolic tangent method. ... 
Analytical solutions of cylindrical and spherical dust ionacoustic solitary waves
ElZahar, Essam Roshdy; Demiray, Hilmi (Elsevier B.V., 201906)In the present work, employing the conventional reductive perturbation method to the field equations of an unmagnetized dusty plasma consisting of inertial ions, Boltzmann electrons and stationary dust particles in the ... 
An application of modified reductive perturbation method to long water waves
Demiray, Hilmi (PergamonElsevier Science Ltd, 201112)In this work, we extended the application of "the modified reductive perturbation method" to long water waves and obtained the governing equations as the KdV hierarchy. Seeking a localized travelling wave solutions to these ... 
An application of modified reductive perturbation method to symmetric regularizedlongwave
Demiray, Hilmi (Işık University Press, 20110324)In this work, we extended the application of "the modified reductive perturbation method" to symmetrical regularized long waves with quadratic nonlinearity and obtained various form of KdV equations as the governing ... 
An application of multipletime scale perturbation method to nonlinear ionacoustic waves
Demiray, Hilmi (Physical Soc Japan, 201202)In this work, by utilizing the multipletime scale expansion method, we studied the propagation of weakly nonlinear waves in a collisionless cold plasma and obtained the governing evolution equations of various order terms ... 
An application of the modified reductive perturbation method to a generalized boussinesq equation
Demiray, Hilmi (Walter De Gruyter GMBH, 201302)In this work, we apply "the modified reductive perturbation method" to the generalized Boussinesq equation and obtain various form of generalized KdV equations as the evolution equations. Seeking a localized travelling ... 
An approximate wave solution for perturbed KDV and dissipative NLS equations: weighted residual method
Demiray, Hilmi (Işık University Press, 20190621)In the present work, we modified the conventional "weighted residual method" to some nonlinear evolution equations and tried to obtain the approximate progressive wave solutions for these evolution equations. For the ... 
Asymptotic solutions of love wave propagation in a covered halfspace with inhomogeneous initial stresses G(3)(1)
Hasanoğlu, Elman; Negin, Masoud (Işık University Press, 2015)The dispersive behavior of Love waves in an elastic halfspace substrate covered by an elastic layer under the effect of inhomogeneous initial stresses has been investigated. Classical linearized theory of elastic waves ... 
Blowup and global existence for a general class of nonlocal nonlinear coupled wave equations
Duruk, Nilay; Erbay, Hüsnü Ata; Erkip, Albert (Academic Press Inc Elsevier Science, 20110201)We study the initialvalue problem for a general class of nonlinear nonlocal coupled wave equations. The problem involves convolution operators with kernel functions whose Fourier transforms are nonnegative. Some wellknown ... 
The boundary layer approximation and nonlinear waves in elastic tubes
Antar, Nalan; Demiray, Hilmi (PergamonElsevier Science, 200009)In the present work, employing the nonlinear equations of an incompressible, isotropic and elastic thin tube and approximate equations of an incompressible viscous fluid, the propagation of weakly nonlinear waves is examined. ... 
The Cauchy problem for a class of twodimensional nonlocal nonlinear wave equations governing antiplane shear motions in elastic materials
Erbay, Hüsnü Ata; Erbay, Saadet; Erkip, Albert (IOP Publishing Ltd, 201104)This paper is concerned with the analysis of the Cauchy problem of a general class of twodimensional nonlinear nonlocal wave equations governing antiplane shear motions in nonlocal elasticity. The nonlocal nature of the ...