Browsing by Author "Rujira Ouncharoen"

Now showing 1 - 5 of 5
  • Default Image
    Item
    Existence and stability analysis for fractional impulsive caputo difference-sum equations with periodic boundary condition
    (MDPI AG, 2020) Rujira Ouncharoen; Saowaluck Chasreechai; Thanin Sitthiwirattham; S. Chasreechai; Department of Mathematics, Faculty of Applied Science, King Mongkut's University of Technology North Bangkok, Bangkok, 10800, Thailand; email: saowaluck.c@sci.kmutnb.ac.th
    In this paper, by using the Banach contraction principle and the Schauder's fixed point theorem, we investigate existence results for a fractional impulsive sum-difference equations with periodic boundary conditions. Moreover, we also establish different kinds of Ulam stability for this problem. An example is also constructed to demonstrate the importance of these results. © 2020 by the authors.
  • Default Image
    Item
    Existence results of a nonlocal fractional symmetric hahn integrodifference boundary value problem
    (MDPI, 2021) Rujira Ouncharoen; Nichaphat Patanarapeelert; Thanin Sitthiwirattham; N. Patanarapeelert; Department of Mathematics, Faculty of Applied Science, King MongkutÕs University of Technology North Bangkok, Bangkok, 10800, Thailand; email: nichaphat.p@sci.kmutnb.ac.th; T. Sitthiwirattham; Mathematics Department, Faculty of Science and Technology, Suan Dusit University, Bangkok, 10300, Thailand; email: thanin_sit@dusit.ac.th
    The existence of solutions of nonlocal fractional symmetric Hahn integrodifference boundary value problem is studied. We propose a problem of five fractional symmetric Hahn difference operators and three fractional symmetric Hahn integrals of different orders. We first convert our nonlinear problem into a fixed point problem by considering a linear variant of the problem. When the fixed point operator is available, Banach and SchauderÕs fixed point theorems are used to prove the existence results of our problem. Some properties of (q, _)-integral are also presented in this paper as a tool for our calculations. Finally, an example is also constructed to illustrate the main results. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
  • Default Image
    Item
    Nonlocal q-symmetric integral boundary value problem for sequential q-symmetric integrodifference equations
    (MDPI AG, 2018) Rujira Ouncharoen; Nichaphat Patanarapeelert; Thanin Sitthiwirattham; N. Patanarapeelert; Department of Mathematics, Faculty of Applied Science, King Mongkut's University of Technology North Bangkok, Bangkok, 10800, Thailand; email: nichaphat.p@sci.kmutnb.ac.th
    In this paper, we prove the sufficient conditions for the existence results of a solution of a nonlocal q-symmetric integral boundary value problem for a sequential q-symmetric integrodifference equation by using the Banach's contraction mapping principle and Krasnoselskii's fixed point theorem. Some examples are also presented to illustrate our results. � 2018 by the authors.
  • Default Image
    Item
    On nonlinear fractional difference equation with delay and impulses
    (MDPI AG, 2020) Rujira Ouncharoen; Saowaluck Chasreechai; Thanin Sitthiwirattham; S. Chasreechai; Department of Mathematics, King Mongkut's University of Technology North Bangkok, Bangkok, 10800, Thailand; email: saowaluck.c@sci.kmutnb.ac.th; T. Sitthiwirattham; Mathematics Department, Suan Dusit University, Bangkok, 10300, Thailand; email: thanin_sit@dusit.ac.th
    In this paper, we establish the existence results for a nonlinear fractional difference equation with delay and impulses. The Banach and Schauder's fixed point theorems are employed as tools to study the existence of its solutions. We obtain the theorems showing the conditions for existence results. Finally, we provide an example to show the applicability of our results. © 2020 by the authors.
  • Default Image
    Item
    STUDY OF INTEGER AND FRACTIONAL ORDER COVID-19 MATHEMATICAL MODEL
    (World Scientific, 2023) Rujira Ouncharoen; Kamal Shah; Rahim Ud Din; Thabet Abdeljawad; A.L.I. Ahmadian; Soheil Salahshour; Thanin Sitthiwirattham; T. Abdeljawad; Department of Mathematics and Sciences, Prince Sultan University, Riyadh, 11586, Saudi Arabia; email: tabdeljawad@psu.edu.sa
    In this paper, we study a nonlinear mathematical model which addresses the transmission dynamics of COVID-19. The considered model consists of susceptible (S), exposed (E), infected (I), and recovered (R) individuals. For simplicity, the model is abbreviated as SEIR. Immigration rates of two kinds are involved in susceptible and infected individuals. First of all, the model is formulated. Then via classical analysis, we investigate its local and global stability by using the Jacobian matrix and Lyapunov function method. Further, the fundamental reproduction number R0 is computed for the said model. Then, we simulate the model through the Runge-Kutta method of order two abbreviated as RK2. Finally, we switch over to the fractional order model and investigate its numerical simulations corresponding to different fractional orders by using the fractional order version of the aforementioned numerical method. Finally, graphical presentations are given for the approximate solution of various compartments of the proposed model. Also, a comparison with real data has been shown. © 2023 The Author(s).