• Title/Summary/Keyword: Laplace transform.

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DENSENESS OF TEST FUNCTIONS IN THE SPACE OF EXTENDED FOURIER HYPERFUNCTIONS

  • Kim, Kwang-Whoi
    • Bulletin of the Korean Mathematical Society
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    • v.41 no.4
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    • pp.785-803
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    • 2004
  • We research properties of analytic functions which are exponentially decreasing or increasing. Also we show that the space of test functions is dense in the space of extended Fourier hyper-functions, and that the Fourier transform of the space of extended Fourier hyperfunctions into itself is an isomorphism and Parseval's inequality holds.

THE INITIAL-BOUNDARY-VALUE PROBLEM OF A GENERALIZED BOUSSINESQ EQUATION ON THE HALF LINE

  • Xue, Ruying
    • Journal of the Korean Mathematical Society
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    • v.45 no.1
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    • pp.79-95
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    • 2008
  • The local existence of solutions for the initial-boundary value problem of a generalized Boussinesq equation on the half line is considered. The approach consists of replacing he Fourier transform in the initial value problem by the Laplace transform and making use of modern methods for the study of nonlinear dispersive wave equation

REMARKS ON THE EXISTENCE OF AN INERTIAL MANIFOLD

  • Kwak, Minkyu;Sun, Xiuxiu
    • Journal of the Korean Mathematical Society
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    • v.58 no.5
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    • pp.1261-1277
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    • 2021
  • An inertial manifold is often constructed as a graph of a function from low Fourier modes to high ones and one used to consider backward bounded (in time) solutions for that purpose. We here show that the proof of the uniqueness of such solutions is crucial in the existence theory of inertial manifolds. Avoiding contraction principle, we mainly apply the Arzela-Ascoli theorem and Laplace transform to prove their existence and uniqueness respectively. A non-self adjoint example is included, which is related to a differential system arising after Kwak transform for Navier-Stokes equations.

HIGHER EIGENVALUE ESTIMATE ON MANIFOLD

  • Kim, Bang-Ok;Robert Gulliver
    • Communications of the Korean Mathematical Society
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    • v.13 no.3
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    • pp.579-587
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    • 1998
  • In this paper we will estimate the lower bound of k-th Dirichlet eigenvalue $ \lambda_{k}$ / of Laplace equation on bounded domain in sphere.

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The Busy Period of the M/M/1 Queue with Bounded Workload

  • Bae, Jong-Ho
    • Proceedings of the Korean Statistical Society Conference
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    • 2002.11a
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    • pp.273-277
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    • 2002
  • In this paper, with martingale argument we derive the explicit formula for the Laplace transform of the busy period of M/M/1 queue with bounded workload which is also called finite dam. Much simpler derivation than appeared in former literature provided.

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LOSS PROBABILITY IN THE PH/M/1/K QUEUE

  • Kim, Jeong-Sim
    • Journal of applied mathematics & informatics
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    • v.24 no.1_2
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    • pp.529-534
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    • 2007
  • We obtain an explicit expression of the loss probability for the PR/M/1/K queue when the offered load is strictly less than one.

SEMIGROUP OF LIPSCHITZ OPERATORS

  • Lee, Young S.
    • Korean Journal of Mathematics
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    • v.14 no.2
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    • pp.273-280
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    • 2006
  • Lipschitzian semigroup is a semigroup of Lipschitz operators which contains $C_0$ semigroup and nonlinear semigroup. In this paper, we establish the cannonical exponential formula of Lipschitzian semigroup from its Lie generator and the approximation theorem by Laplace transform approach to Lipschitzian semigroup.

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A novel analytical approach for advection diffusion equation for radionuclide release from an area source

  • Esmail, S.;Agrawal, P.;Aly, Shaban
    • Nuclear Engineering and Technology
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    • v.52 no.4
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    • pp.819-826
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    • 2020
  • The method of the Laplace transform has been used to obtain an analytical solution of the three-dimensional steady state advection diffusion equation for the airborne radionuclide release from any nuclear installation such as the power reactor in an area source. The present treatment takes into account the removal of the pollutants through the nuclear reaction. We assume that the pollutants are emitted as a constant rate from the area source. This physical consideration is achieved by assuming that the vertical eddy diffusivity coefficient should be a constant. The prevailing wind speed is a constant in 𝑥- direction and a linear function of the vertical height z. The present model calculations are compared with the other models and the available data of the atmospheric dispersion experiments that were carried out in the nuclear power plant of Angra dos Reis (Brazil). The results show that the present treatment performs well as the analytical dispersion model and there is a good agreement between the values computed by our model and the observed data.

A magneto-thermo-viscoelastic problem with fractional order strain under GN-II model

  • Deswal, Sunita;Kalkal, Kapil Kumar;Sheoran, Sandeep Singh
    • Structural Engineering and Mechanics
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    • v.63 no.1
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    • pp.89-102
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    • 2017
  • In this work, we present a theoretical framework to study the thermovisco-elastic responses of homogeneous, isotropic and perfectly conducting medium subjected to inclined load. Based on recently developed generalized thermoelasticity theory with fractional order strain, the two-dimensional governing equations are obtained in the context of generalized magnetothermo-viscoelasticity theory without energy dissipation. The Kelvin-Voigt model of linear viscoelasticity is employed to describe the viscoelastic nature of the material. The resulting formulation of the field equations is solved analytically in the Laplace and Fourier transform domain. On the application of inclined load at the surface of half-space, the analytical expressions for the normal displacement, strain, temperature, normal stress and tangential stress are derived in the joint-transformed domain. To restore the fields in physical domain, an appropriate numerical algorithm is used for the inversion of the Laplace and Fourier transforms. Finally, we have demonstrated the effect of magnetic field, viscosity, mechanical relaxation time, fractional order parameter and time on the physical fields in graphical form for copper material. Some special cases have also been deduced from the present investigation.