Sürdürülebilir Kalkınma Amaçları

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• MakaleAçık Erişim2025/r/gumushane/14307
  Mathematical analysis of fractional order Covid 19 epidemic model

  Açikgöz, Pınar; Merdan, Mehmet

  This article aims to examine the dynamics of the fractional epidemic model of covid 19. The model in question incorporates the notion of a compatible derivative. Given their consistent and worldwide characteristics, fractional derivatives are presently employed to address nu-merous practical issues. In addition, we employ two numerical techniques, namely the con-formal differential transform and the variational iteration approach, to provide an approxi-mate solution for the given model. The research closes by providing an in-depth analysis and visually representing the numerical findings. Furthermore, it has been demonstrated that the solution obtained is convergent.

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• MakaleAçık Erişim2025/r/gumushane/14060
  Investigation of fractional order covid-19 model with q-homotopy analysis transform method

  Merdan, Mehmet; Açikgöz, Pınar

  The primary objective of this paper is to derive approximate analytic solutions for the time fractional-order Covid-19 model by employing the q-homotopy analysis transform method (q-HATM) and the Laplace transform homotopy perturbation method (LT-HPM). The covid 19 model is a system of five-dimensional nonlinear ordinary differential equations. Moreover, this method applies even to more complex partial differential equations originating from mathematical biology, demonstrating computational efficiency and wide application. In this study, Caputo fractional derivative is used to obtain the fractional system and Laplace transformation is applied to analyze the approximate solutions of the system. Graphical results are presented and discussed quantitatively to illustrate the approximate solution. Copyright 2021, Yıldız Technical University.

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• MakaleYayıncıda açık erişim2024/r/gumushane/16546
  Solutions of linear Fredholm integral equations with the three- step iteration method

  Cona, Lale; Sengül, Kadir

  In this article, the solution of the second type of nonhomogeneous linear Fredholm integral equations is investigated using a three-step iteration algorithm. It has been shown that the sequences obtained from this algorithm converge to the solution of the mentioned equations. Morever, data dependency is obtained for the second type of nonhomogeneous linear Fredholm integral equations. This result is supported by an example.

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• MakaleAçık Erişim2024/r/gumushane/12754
  1D fuzzy inverse logic method and its use in the design of thick reinforced concrete columns

  Ertekin, Özteki̇N

  In this study, without using any uniaxial force and bending moment (N-M) interaction diagrams, designs were carried out on thick columns subjected to uniaxial bending and compression by a novel 1 dimensional (1D) Fuzzy Inverse Logic (FIL) method. For this purpose, firstly, a Fuzzy Logic (FL) model was developed and the FIL method was applied to it thereafter. While, the cross-section width (b), the cross-section height (h), the rebar diameter(f), the numbers of reinforcement rows (Rx and Ry) placed into the cross-section in X and Y directions, the characteristic concrete compressive strength(fck) and the axial force ratio Nr=N/ (b.h.(fck/1.5)) were taken as variable parameters, concrete cover thickness (c), rebar strength (fyd) and k1 parameter defined for the concrete pressure block were kept constant in the developed FL model. After designs were performed on 15 columns having different variable variations by the 1D FIL method, moment bearing capacities of the obtained 9737 alternative designs determined conventionally were compared with the desired moment values. The evaluations made on the comparisons show that the FIL method is not only a very effective artificial intelligence method for the design of reinforced concrete thick columns but also a promising method for many other problems such as control, optimization, design, etc.

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• MakaleAçık Erişim2024/r/gumushane/12623
  Investigation of friction behavior of TiO2: Al2O3 composite coating formed on AA2024 alloy by micro-arc oxidation

  Boynueğri̇ Kaplan, Emine; Şüküroğlu, Ebru Emine

  In this study, an alumina (Al2O3) ceramic coating and a composite coating containing titanium dioxide (TiO2) particles were prepared on surfaces of AA2024 substrates by micro-arc oxidation (MAO) treatment. The effects of micro-sized (≈20-30 µm) TiO2 particles incorporated into electrolyte on the microstructure, phase and chemical composition, thickness, and friction behavior of the coating were investigated. The surface morphologies of the coatings were analyzed by scanning electron microscopy (SEM). The phase and chemical compositions of the coatings were evaluated by means of X-ray diffraction (XRD) and energy-dispersive X-ray spectrometry (EDS), respectively. The friction coefficient of the coatings was investigated using a pin-on-disc tribometer under condition of dry slip sliding. Moreover, the wear tracks were analyzed by SEM. Addition of TiO2 particles into the electrolyte resulted in the reduction in number of pores and formation of smaller and more uniform pores in comparison with the Al2O3 ceramic coating. XRD analyses demonstrated that the TiO2:Al2O3 composite coating was composed of anatase-TiO2 and rutile-TiO2, as well as pure aluminum, α-Al2O3 and γ-Al2O3 which are the primary phases. The friction tests showed a significant reduction in the friction coefficient of the composite coated samples which contains titanium oxide (TiO2) particles in comparison with Al2O3 coated and uncoated samples. Copyright 2021, Yıldız Technical University.

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• MakaleAçık Erişim2024/r/gumushane/12439
  Analysis of grover's quantum search algorithm on a classical computer: Identifying opportunities for improvement

  Necati, Çeli̇K; Bi̇Ngöl, Özkan

  In this paper, Grover’s quantum search algorithm is analyzed using a classical computer by calculating the amplitudes and the probabilities of finding a single marked state for n=5, 10, 15, 20, 25, and 27 qubit states. The calculations show that the marked state can be found in iterations, where N = 2n is the number of items. The possibility of improving Grover’s search algorithm to find a single item in N search elements is discussed by calculating the amplitudes and hence the probabilities of finding a single marked state for n=5, 10, 15, 20, 25, 30, 35, 40, 45, and 50 qubit states. The calculations showed that the marked state could be found with sufficiently high probability in (ln(N)) iterations. This is quite a remarkable speed-up that can be achieved to find a single marked element in an unsorted N search element. Copyright 2021, Yıldız Technical University.

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• MakaleAçık Erişim2024/r/gumushane/11562
  On solutions of time fractional order random HIV/AIDS modelling

  Merdan, Mehmet; Öktem, Selami

  In this study, The fractional random HIV/AIDS model approximate analytical solutions were produced using the differential transformation method. The approximate analytical solution of the fractional order Random HIV/AIDS model was obtained with the help of the differential transformation method. For the fractional random HIV/AIDS model, which was created by choosing the initial conditions from the exponential, beta, and normal distributions, graphic simulations of the expected value, variance, and confidence intervals of the most commonly used probability characteristics were obtained with the help of the MATLAB package program. Results obtained are interpreted.

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• MakaleAçık Erişim2023/r/gumushane/14449
  Wong-Zakai approximation for stochastic models of smoking

  Şengül, Süleyman; Beki̇Ryazici, Zafer; Merdan, Mehmet

  In this study, Wong-Zakai approximation method has been used to obtain approximate solutions for two compartmental models of smoking dynamics. Stratonovich stochastic differential equation systems are obtained for these two stochastic models for the application of Wong-Zakai method. Wong-Zakai method is used together with the predictor-corrector deterministic approximation method where Adams-Bashforth method is used as the predictor pair and Adams-Moulton method is used as the corrector pair. Stochastic Runge-Kutta IV, Euler-Maruyama and stochastic Runge-Kutta strong order 1.0 schemes are also used to investigate the models and the results are compared to the results from Wong-Zakai approximation. The comparison shows that Wong-Zakai method is a reliable tool for the analysis of stochastic models and can be considered as an alternative investigation method for modeling studies. Solution graphs, error graphs and numerical results have been given as evidence to show that Wong-Zakai method can also be a reliable method for analyzing various models. An alternate technique for parallelizing the algorithm has also been given to decrease CPU times for Wong-Zakai method. This technique is suggested to overcome the extra calculation load that comes with Wong-Zakai method.

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• MakaleAçık Erişim2023/r/gumushane/14381
  Solutions of multiplicative linear differential equations via the multiplicative power series method

  Yalcin, Numan; Dedeturk, Mutlu

  In this study, fundamental concepts of multiplicative analysis is given. Also, definitions of multiplicative Taylor series (MTS), multiplicative Taylor polynomials (MTP), and multiplicative power series (MPS) are given. Solutions of higher-order multiplicative linear differential equations (MLDE) are investigated with the help of the MPS method. Applications of MPS method are done for first, second, and third-order multiplicative ordinary linear differential equations. Copyright 2021, Yıldız Technical University.

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• MakaleAçık Erişim2023/r/gumushane/11455
  Detection of pneumonia from pediatric chest X-ray images by transfer learning

  Demir, Yasin; Bingöl, Özkan

  When pathogens such as viruses, bacteria and fungi attack the lungs, the alveoli fill with inflamed fluid, causing pneumonia. Early diagnosis of this disease, which has fatal outcomes especially in children under 5 years old, is very important in controlling undesirable situations. Chest X-ray images play an important role in the diagnosis of pneumonia. In addition, the fact that the amount of radiation is lower than imaging devices such as tomography and the possibility of being accessible even from rural areas creates an advantage for X-ray devices. However, X-ray images that are not always clear or human conditions such as fatigue and lack of attention can make it difficult for specialists to detect pneumonia. In this study, a transfer learning-based convolutional neural network (CNN) approach is proposed, which can help specialists in the early and accurate diagnosis of pneumonia in children and, classify healthy and diseased individuals through Chest X-ray images. As a result of the study, an original CNN was proposed by adding additional layers to the AlexNet architecture layers and a test accuracy of 96.31% was obtained. Copyright 2021, Yıldız Technical University.

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