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https://hdl.handle.net/20.500.12587/18125

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The singular eigenfunction method: the critical slab problem for linearly anisotropic scattering
(Carl Hanser Verlag, 2005) Türeci, Recep Gökhan; Güleçyüz, Mustafa Çetin; Kaskas, A.; Tezcan, C.
The critical slab problem for linearly anisotropic scattering is investigated using the singular eigenfunction method. The third form of the transport equation is considered. The singular eigenfunctions for linearly anisotropic scattering are inserted into the Green's function. This Green's function with the full range orthogonality relations of the singular eigenfunctions together with the appropriate boundary conditions provide the criticality equation. This equation is exact and leads as shown in tables to fast converging numerical results.
The Slab Albedo problem with the Anli-Gungor scattering function
(Indian Assoc Cultivation Science, 2023) Türeci, Recep Gökhan
The slab albedo problem is investigated here for the Anli-Gungor scattering function with its quadratic term. The scattering is the function of Legendre polynomials, and it includes t scattering parameter. The analytical calculations are performed with HN method, and the numerical results are calculated using Wolfram Mathematica software. The interpolation technique is applied to the calculated results in this study. Thus, the results are compared with the literature data when t parameter goes to zero. A second comparison is performed for the linear-quadratic Mika anisotropic scattering function and the quadratic Anli-Gu spexpressioncing diexpressioneresis ngo spexpressioncing diexpressioneresis r scattering function. Both scattering functions give the same results under the certain situations. These situations are also investigated.
The Milne Problem for Linear-Triplet Anisotropic Scattering with HN Method
(Taylor & Francis Inc, 2022) Gülderen, D.; Şahni, D. C.; Türeci, Recep Gökhan; Aydın, Abdullah
The Milne problem is investigated for the linear-triplet anisotropic scattering with H-N method in this study. The scattering function is the linear combination of linear anisotropic scattering and triplet anisotropic scattering in Mika's scattering. The positivity condition is needed to find physical results since the scattering function defines the scattering probabilities. It defines the relationship between the scattering coefficients. H-N method is based on using the Case method. Therefore, properties of the Case method should be derived for the scattering function. The linear anisotropic scattering is the dominant scattering according to the calculated results.
The Milne Problem with the Anli-Gungor Scattering
(Taylor & Francis Inc, 2022) Türeci, Recep Gökhan
Recently developed the Anli-Gungor scattering function is applied to the Milne problem in this study. It is the function of Legendre polynomials with t parameter which can be called as scattering parameter. The extrapolation distance values are calculated for varying t parameters and varying secondary neutron numbers with the H-N method. The numerical results are calculated by 40th approximation in order to get high precision results. The calculated extrapolation distance results are very convergence. Since there is no a similar study for the Milne problem with the Anli-Gungor scattering in the literature, the interpolation technique is applied to the H-N method results. Thus, the isotropic scattering results could be determined by t -> 0 limit.
The Criticality Problem for the Anisotropic Scattering with Two Discrete Eigenvalues
(Taylor & Francis Inc, 2024) Türeci, R. Gökhan; Bozkir, A. Z.; Sahni, D. C.
In a recent study, the eigenvalue numbers of Case eigenfunctions were investigated for the situation of anisotropic scattering. The results of this study is applied to the criticality problem. The investigation is performed with two different methods: the singular value decomposition (SVD) method and the HN method. The former was recently improved using the SVD to solve the matrix of the problem, and the latter is based on the usage of the Case method for proper boundary conditions. We have two different eigenvalues for the given number of secondary neutrons and the scattering parameter. Either these eigenvalues are both complex, or one is complex and one is real. The investigation is to show the effect of the second eigenvalues over the critical thickness values.
Some Numerical Results of the Albedo Problem in Spherical Geometry with Linearly Anisotropic Scattering
(Taylor & Francis Inc, 2024) Bozkır, A. Z.; Türeci, Recep Gökhan; Sahni, D. C.
We examine the effect of linear anisotropic scattering on the solution of spherical geometry transport problems. We consider the albedo problem of a solid homogeneous sphere with linearly anisotropic scattering and write two matrix equations to solve the albedo problem with the HN and SVD methods in pseudo slab geometry. These methods are based on Case method of singular eigenfunctions. The numerical results of both methods are in agreement with each other.
Analysis of Occupational Accidents According to The Sectors in Turkey
(Gazi Univ, 2012) Ceylan, Hüseyin
Occupational accidents lead to serious problems in Turkey and in many other countries. The most important results of occupational accidents are deaths, injuries or disabilities. In addition, many other important work-related accidents cause serious financial losses. As it is all around the world, there are certain sectors in which occupational accidents mostly occur. Taking the number of accidents, the number of permanent incapacities and the number of deaths into account, these sectors can be listed as Mining, Metal, and Construction. These three sectors are indicated as the priority sectors by Republic of Turkey Ministry of Labour and Social Security in terms of the struggle against occupational accidents. When the data on the accidents at work between 2004 and 2010 is analyzed, it is seen that 46,4% of the accidents and 41,1% of the deaths in Turkey occurred only in these three sectors. Therefore, examining these three sectors would enable to reveal their specific problems regarding occupational safety. In this study, using the accident data from the year 2004 to 2010 by SSI (Social Security Institution), all the accidents which occurred in Turkey and the accidents specifically in Mining, Metal and Construction sectors were compared in terms of the parameters, which are also used by the international accident statisticians. (Since it has not been completed yet, the accident data on the year 2011 was not included in this study.)
Symbol detection using the differential evolution algorithm in MIMO-OFDM systems
(Tubitak Scientific & Technological Research Council Turkey, 2013) Seyman, Muhammet Nuri; Taşpınar, Necmi
Channel estimation and symbol detection in multiple-input and multiple-output (MIMO)-orthogonal frequency division multiplexing (OFDM) systems are essential tasks. Although the maximum likelihood (ML) detector reveals excellent performance for symbol detection, the computational complexity of this algorithm is extremely high in systems with more transmitter antennas and high-order constellation size. In this paper, we propose the differential evolution (DE) algorithm in order to reduce the search space of the ML detector and the computational complexity of symbol detection in MIMO-OFDM systems. The DE algorithm is also compared to some heuristic approaches, such as the genetic algorithm and particle swarm optimization. According to the simulation results, the DE has the advantage of significantly less complexity and is closer to the optimal solution.
Partial Range Completeness of Case Eigenfunctions and Numerical Solution of Singular Integral Equations of Particle Transport Problems
(TAYLOR & FRANCIS INC, 2020) Sahni, D. C.; Tureci, R. G.; Bozkir, A. Z.
We study numerical solution of Singular Integral Equations (SIE) of particle transport theory. We convert them into matrix equations by standard discretization process. It is found that the matrices are highly ill-conditioned and can be solved by Singular Value Decomposition (SVD) method. One expects that matrices resulting from expansions over Partial Range will not be ill-conditioned. We find this is not true though their ill-conditioning is an order of magnitude less than those of full or half range. Reasons for this phenomenon are explained.
Half-space albedo problem for Inonu, linear and quadratic anisotropic scattering
(Korean Nuclear Soc, 2020) Tureci, R. G.
This study is concerned with the investigation of the half-space albedo problem for "Inonu-linearquadratic anisotropic scattering" by the usage of Modified FN method. The method is based on Case's method. Therefore, Case's eigenfunctions and its orthogonality properties are derived for anisotropic scattering of interest. Albedo values are calculated for various linear, quadratic and inonu anisotropic scattering coefficients and tabulated in Tables. (C) 2019 Korean Nuclear Society, Published by Elsevier Korea LLC.
Modified F-N solution of the neutron transport equation for the Milne problem with FBIS kernel
(Indian Assoc Cultivation Science, 2019) Ersoy, A.; Tureci, G.; Senyigit, M.; Gulecyuz, M. C.
The solution of the Milne problem is studied by one-speed neutron transport equation in plane geometry with Inonu's scattering kernel, which is known as a linear combination of the forward, backward and isotropic scattering kernel (FBIS kernel). The solution of the neutron transport equation with Inonu's scattering kernel can be written in terms of the solution of the neutron transport equation for isotropic scattering case. The extrapolation distance is calculated with modified F-N (or method. The numerical values of the extrapolation distance are obtained depending on the secondary neutron numbers and anisotropy coefficients and compared with the available data in the literature values.
Discrete Eigenvalues of Case Spectrum with Anisotropic Scattering
(Taylor & Francis Inc, 2018) Sahni, D. C.; Tureci, R. G.
Discrete eigenvalues of a one-speed linear transport equation with anisotropic scattering are studied. It is shown that there is only one pair of real discrete eigenvalues for linear, quadratic, or triplet scattering for a nonmultiplicative medium. For a multiplicative medium there is one imaginary pair of eigenvalues or at most four eigenvalues. These can form one real and one imaginary pair, two imaginary pairs, or a quartet. The range of parameters for these different situations is derived analytically. These are then supported by numerical results that are tabulated in tables for each type of scattering.
Adaptive arrangement of cyclic prefix length for MC-CDMA systems via multi-objective bat algorithm
(Springer London Ltd, 2018) Seyman, Muhammet Nuri
Multi-carrier multiplexing systems, used in high bit rate communication applications, are more affected by the time- or frequency-dependent fading effects incurring in the channel than the single-carrier systems. When the fading effects at multi-carrier systems are not taken into consideration, inter-carrier interference or inter-symbol interferences that cause bit error rate increase at the receiver would occur. In order to eliminate these interference effects, the cyclic prefix is used in MC-CDMA systems, which are the kind of multi-carrier systems. However, determining how long the CP length is to be used will directly affect both the error and the capacity performance of the system. In this study, multi-objective bat algorithm is proposed for the adaptive arrangement of the CP lengths according to the channel conditions. Contrary to the standard CP determination methods, not only the bit errors are minimized, but also the maximization of the channel capacity is provided by the utilization of MOBA.
Subcarrier Allocation Algorithm Based on Greedy-Like in Multi Carrier Code Division Multiple Access Systems
(Kaunas Univ Technology, 2017) Seyman, Muhammet Nuri; Demiral, Bircan
One of the most important issues to be taken into consideration in multi carrier communication systems with multi users is the assignment of the available resources to the users efficiently. Thus, how to determine the number of subcarriers to be allocated to the users has an important role with regards to data rate and error performance of the system when active users are increased in multi carrier system. In this study by using Greedy-Like algorithm, the subcarriers in MC-CDMA systems are optimal allocated to the users and the efficiency of this algorithm compared with other algorithms in terms of bit error and bit rate performance.
Half-space albedo problem with modified F-N' method for linear and quadratic anisotropic scattering
(Carl Hanser Verlag, 2017) Tureci, R. G.; Tureci, D.
One speed, time independent and homogeneous medium neutron transport equation can be solved with the anisotropic scattering which includes both the linear anisotropic and the quadratic anisotropic scattering properties. Having solved Case's eigenfunctions and the orthogonality relations among these eigenfunctions, some neutron transport problems such as albedo problem can be calculated as numerically by using numerical or semi-analytic methods. In this study the half-space albedo problem is investigated by using the modified F-N method.
An approach to estimate occupational accidents using least-squares support vector machines
(Academic Publication Council, 2017) Ceylan, Huseyin; Parlakyildiz, Sakir
Least-squares support vector machines represent an emerging technique that has been adopted to estimate accidents. In this study, occupational accident estimation models were developed using the least-squares support vector machine method for the Republic of Turkey. In addition, linear regression analysis, nonlinear regression analysis, and artificial neural network models were considered. During the development phase of the models, statistical data from 1970 to 2012 were used to consider parameters such as insured workers, workplaces, occupational accidents, deaths, and permanent incapacities. Using these models, the numbers of accidents, deaths, and permanent incapacities resulting from occupational accidents were estimated for three different scenarios in the Republic of Turkey through the end of 2025. The performances of the developed models were evaluated considering the mean absolute percent errors and the mean absolute errors. In addition, we compared the least-squares support vector machine, linear regression analysis, nonlinear regression analysis, and artificial neural network methods in terms of their estimation performances. Our simulation results demonstrate that the proposed least-squares support vector machine model outperforms other techniques in terms of accuracy and has a rapid convergence capability when estimating occupational accidents.
Slab albedo for linearly and quadratically anisotropic scattering kernel with modified F-N method
(Carl Hanser Verlag, 2017) Tureci, R. G.; Tureci, D.
One speed, time independent and homogeneous medium neutron transport equation is solved with the anisotropic scattering which includes both the linearly and the quadratically anisotropic scattering kernel. Having written Case's eigenfunctions and the orthogonality relations among of these eigenfunctions, slab albedo problem is investigated as numerically by using Modified F-N method. Selected numerical results are pesented in tables.
The critical slab problem for pure-triplet anisotropic scattering by singular eigenfunction method
(Carl Hanser Verlag, 2017) Tureci, R. G.; Tureci, D.
The infinite medium Green function can be written by using the jump condition, found Case's eigenfunctions. Thus, any reactor theory problem which is inplane geometry such the criticality problem as can be investigated by using the proper boundary conditions and suggested flux definitions. By using the criticality equation the critical thicknesses can be calculated as numerically. The selected numerical results can be tabulated.
A Novel Subcarrier Allocation Algorithm for MC–CDMA Systems
(Slovak Univ Technology, 2016) Seyman, Muhammet Nuri; Sacakli, Bircan
Multi carrier modulation techniques such as MC-CDMA are used in high-speed communication applications. Due to MC-CDMA being a multiuser in technology, the subcarrier quantity allocated per user decreases in case the quantity of active users increases. Consequently, data rates per user are reduced with the increase in the bit error rate (BER). Efficient allocation of subcarriers to users within the system can aid the overcoming of this problem. This study develops a new algorithm for subcarrier allocation and system performance improvement in terms of BER, and data rates in comparison to other algorithms were ensured.
Solving the criticality problem with the reflected boundary condition for the triplet anisotropic scattering with the modified FN method
(Carl Hanser Verlag, 2015) Türeci, R. Gökhan
One speed, time independent neutron transport equation in slab geometry can be solved with the triplet anisotropic scattering for the criticality problem with the reflected boundary condition. The value of the critical slab thickness is investigated numerically by using the Modified F-N (H-N) method. Case's eigenfunctions, normalization relation and orthogonality relations must be derived for this scattering in order to use the Modified FN method. Some selected values, which can be calculated from the criticality equation, can be tabulated. Also the term which comes from the Poincare-Bertrand formula may be added to the orthogonality formula of the continuum eigenfunction.

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