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Article Citation - WoS: 3Citation - Scopus: 3Modeling and Measurement of Human Body Blockage Loss at 28 Ghz(Taylor & Francis Ltd, 2023) Benzaghta, Mohamed; Gokdogan, Bengisu Yalcinkaya; Coruk, Remziye Busra; Kara, AliMillimeter-wave (mm-Wave) spectrum is an essential enabler to the fifth generation (5G) wireless technology. Humans are one of the most noticeable blockers that cause temporal variation in indoor radio channels. This paper presents human blockage measurements at 28 GHz, with several humans of different sizes. The effect of the crossing orientations of the human bodies is investigated for three different transmitter heights. A human blockage model based on the Fresnel diffraction scheme is shown to be applicable in estimating the human blockage loss in indoor radio links considering various body sizes, different crossing orientations, and different transmitter heights. The findings reported in this paper could help improve indoor radio channel models at 28 GHz bands for 5G technologies considering the presence of human body blockages.Article Citation - WoS: 5Citation - Scopus: 5Optical Properties of Tlgaxin1-x< Mixed Crystals (0.5 ≤ x ≤ 1) by Spectroscopic Ellipsometry, Transmission, and Reflection(Taylor & Francis Ltd, 2014) Isik, M.; Delice, S.; Gasanly, N. M.The layered semiconducting TlGaxIn1-xSe2-mixed crystals (0.5 <= x <= 1) were studied for the first time by spectroscopic ellipsometry measurements in the 1.2-6.2 eV spectral range at room temperature. The spectral dependence of the components of the complex dielectric function, refractive index, and extinction coefficient were revealed using an optical model. The interband transition energies in the studied samples were found from the analysis of the second-energy derivative spectra of the complex dielectric function. The effect of the isomorphic cation substitution (indium for gallium) on critical point energies in TlGaxIn1-xSe2 crystals was established. Moreover, the absorption edge of TlGaxIn1-xSe2 crystals have been studied through the transmission and reflection measurements in the wavelength range of 500-1100 nm. The analysis of absorption data revealed the presence of both optical indirect and direct transitions. It was found that the energy band gaps decrease with the increase of indium content in the studied crystals.Article Citation - WoS: 1Citation - Scopus: 1On the Accuracy of an Emitter Localization Method Based on Multipath Exploitation in Realistic Scenarios(Taylor & Francis Ltd, 2022) Al Imran, M. A.; Ank, E.; Dalveren, Y.; Tabakcioglu, M. B.; Kara, A.This study aims to evaluate the accuracy of a method proposed for passive localization of radar emitters around irregular terrains with a single receiver in Electronic Support Measures systems. Previously, the authors targeted only the theoretical development of the localization method. In fact, this could be a serious concern in practice since there is no evidence regarding its accuracy under the real data gathered from realistic scenarios. Therefore, an accurate ray-tracing algorithm is adapted to enable the implementation of the method in practice. Then, realistic scenarios are determined based on the geographic information system map generated to collect high-resolution digital terrain elevation data, as well as realistic localization problems for radar emitters. Next, simulations are performed to test the localization method. Thus, the performance of the method is verified for practical implementation in the electronic warfare context for the first time. Lastly, the performance bounds of the method are discussed.Article Citation - WoS: 1Citation - Scopus: 1Calculation of Overlap Integrals Over Slater-Type Spinor Orbitals of Arbitrary Half-Integral Spin Using Auxiliary Functions(Taylor & Francis Ltd, 2012) Guseinov, I. I.; Aydin, R.; Bagci, A.Analytical relations are derived for two-center overlap integrals over the basis set of 2(2s + 1)-component Slater-type spinor orbitals, which can be used for the solution of generalized Dirac equation, introduced by one of the authors, in the linear combination of atomic orbitals approach, where s = 1/2, 3/2, 5/2,.... These relativistic integrals are reduced to the linear combinations of two-center non-relativistic overlap integrals of scalar Slater-type orbitals. The calculations for non-relativistic overlap integrals are performed with the arbitrary values of quantum numbers, screening constants and the location of orbitals. To obtain more accurate results from the calculations, the well-known auxiliary functions A(n) and B-n are used. It is observed that the computer program carrying out these extended calculations, indeed, works without any restrictions and in all ranges of orbital parameters.Article Citation - WoS: 4An Introduction To Complex Functions on Products of Two Time Scales(Taylor & Francis Ltd, 2006) Bohner, Martin; Guseinov, Gusein SH.In this paper, we study the concept of analyticity for complex-valued functions of a complex time scale variable, derive a time scale counter-part of the classical Cauchy-Riemann equations, introduce complex line delta and nabla integrals along time scales curves, and obtain a time scale version of the classical Cauchy integral theorem.Article Citation - Scopus: 1Improved Parallel Preconditioners for Multidisciplinary Topology Optimisations(Taylor & Francis Ltd, 2016) Akay, H. U.; Oktay, E.; Manguoglu, M.; Sivas, A. A.Two commonly used preconditioners were evaluated for parallel solution of linear systems of equations with high condition numbers. The test cases were derived from topology optimisation applications in multiple disciplines, where the material distribution finite element methods were used. Because in this optimisation method, the equations rapidly become ill-conditioned due to disappearance of large number of elements from the design space as the optimisations progresses, it is shown that the choice for a suitable preconditioner becomes very crucial. In an earlier work the conjugate gradient (CG) method with a Block-Jacobi preconditioner was used, in which the number of CG iterations increased rapidly with the increasing number processors. Consequently, the parallel scalability of the method deteriorated fast due to the increasing loss of interprocessor information among the increased number of processors. By replacing the Block-Jacobi preconditioner with a sparse approximate inverse preconditioner, it is shown that the number of iterations to converge became independent of the number of processors. Therefore, the parallel scalability is improved.Article Citation - WoS: 2Citation - Scopus: 5Schwarz problem for higher order linear equations in a polydisc(Taylor & Francis Ltd, 2017) Aksoy, U.; Celebi, A. O.In this paper, we discuss the Schwarz boundary value problem for higher order linear complex differential equations in the unit polydisc of C-2. After the relevant preparations, we give the solution for a model equation with homogeneous boundary conditions. Then we obtain the solutions of a linear equation involving Schwarz boundary conditions on the unit polydisc.Article Citation - WoS: 4Citation - Scopus: 3Some Limit Relationships Between Some Two-Variable Finite and Infinite Sequences of Orthogonal Polynomials(Taylor & Francis Ltd, 2021) Guldogan Lekesiz, Esra; Aktas, RabiaThe aim of paper is to give some limit relationships between finite and infinite sequences of orthogonal polynomials in two variables and to obtain the well-known relations of some infinite sets of two-variable orthogonal polynomials by taking limit of the properties verified by finite classes of two-variable orthogonal polynomials. Furthermore, the fourth-order partial differential equations satisfied by the polynomials, which are the products of finite orthogonal polynomials, are presented and by taking limit of the derived fourth-order equations, partial differential equations for some infinite sequences of two-variable orthogonal polynomials are found.Article Citation - WoS: 6Citation - Scopus: 6A Boundary Value Problem for Second Order Nonlinear Difference Equations on the Semi-Infinite Interval(Taylor & Francis Ltd, 2002) Guseinov, GSIn this paper, we consider a boundary value problem (BVP) for nonlinear difference equations on the discrete semi-axis in which the left-hand side being a second order linear difference expression belongs to the so-called Weyl-Hamburger limit-circle case. The BVP is considered in the Hilbert space l(2) and is formed via boundary conditions at a starting point and at infinity. Existence and uniqueness results for solutions of the considered BVP are established.Article Reconfiguring Stoicism: Convergence of Self-Improvement and Masculinity on TikTok(Taylor & Francis Ltd, 2025) Agaoglu, ErhanThis research examines the multimodal representations of Stoic content within TikTok. The research aimed to explore the multifaceted structure of an emerging digital philosophy discourse and its implications for contemporary socio-cultural dynamics. It explores a fragmented version of Stoicism, focussing on the affordances of algorithm-driven platforms and modularity principles. For multimodal discourse analysis, 20 highly viewed (>300,000) videos under the hashtags of #stoic and #stoicism are selected through purposeful sampling. It identifies the emergence of a fragmented Stoicism, built upon platform affordances and audio-visual modularity. Emerging themes include self-improvement, being dangerous and traditional masculinity remarking a divergence from popular and classical interpretations of Stoicism. Through these key themes, construction of an arbitrary link between hegemonic masculinity, glorified individualism and Stoicism is explored. Employing elements of aggression, self-isolation and self-improvement, TikTok content creates a novel discourse of Stoicism which is elusive, abstract, and reliant on visually driven narratives.
