Bekiryazici, Z.; Kesemen, T.; Merdan, M.; Khaniyev, T.

In this study, we investigate a compartmental model of Zika Virus transmission under random effects. Random effects enable the analysis of random numerical characteristics of transmission, which cannot be modeled through deterministic equations. Data obtained from Zika studies in the literature are used along with heavy tailed random effects to obtain new random variables for the parameters of the deterministic model. Finally, simulations of the model are carried out to analyze the random dynamics of Zika Virus transmission. Deterministic results are compared with results from the simulations of the random system to underline the advantages of a random modeling approach. It is shown that the random model provides additional results for disease transmission dynamics such as results for standard deviation and coefficients of variation, making it a valuable alternative to deterministic modeling. Random results suggest around 90% - 120% coefficient of variation for the random model underlining the fact that the randomness should not be ignored for the transmission of this disease.

Sengul, S.; Bekiryazici, Z.; Merdan, M.

In this study, Wong-Zakai approximation method has been applied for the analysis of stochastic differential equations appearing in engineering sciences. Wong-Zakai approximation has been used with similar stochastic approximation methods to compare the approximate solutions of the problems and comment on the performance of the method. Models for lake pollution and computer virus spread under antivirus protection have been used with nonlinear stochastic noise as numerical examples to demonstrate the efficiency of Wong-Zakai method.

Merdan, M.

In this article, an analytical approximate solution of nonlinear fractional convection-diffusion with modified Riemann-Liouville derivative was obtained with the help of fractional variational iteration method (FVIM). A new application of fractional variational iteration method (FVIM) was extended to derive analytical solutions in the form of a series for this equation. It is indicated that the solutions obtained by the FVIM are reliable and an effective method for strongly nonlinear partial equations with modified Riemann-Liouville derivative.

Yildirim, A.; Gökdogan, A.; Merdan, M.; Lakshminarayanan, V.

An approximate analytical solution in the form of a rapidly convergent series for tracing light rays through an inhomogeneous graded index medium is developed, using the multi-step differential transform method based on the classical differential transformation method. Numerical results are compared to those obtained by the fourth-order Runge - Kutta method to illustrate the precision and effectiveness of the proposed method. Results are given in explicit and graphical forms.

Merdan, M.; Gokdogan, A.; Erturk, V.S.

In this paper, the approximate solution of the differential system modeling HIV infection of CD4+ T cells is obtained by a reliable algorithm based on an adaptation of the standard variational iteration method (VIM), which is called the multi-stage variational iteration method(MSVIM). A comparison between MSVIM and the fourthorder Runge-Kutta method (RK4-method) reveal that the proposed technique is a promising tool to solve the considered problem.