• Title/Summary/Keyword: transformations

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Canonical Transformations for Time-Dependent Harmonic Oscillators

  • Park, Tae-Jun
    • Bulletin of the Korean Chemical Society
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    • v.25 no.2
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    • pp.285-288
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    • 2004
  • A canonical transformation changes variables such as coordinates and momenta to new variables preserving either the Poisson bracket or the commutation relations depending on whether the problem is classical or quantal respectively. Classically canonical transformations are well established as a powerful tool for solving differential equations. Quantum canonical transformations have been defined and used relatively recently because of the non-commutativeness of the quantum variables. Three elementary canonical transformations and their composite transformations have quantum implementations. Quantum canonical transformations have been mostly used in time-independent Schrodinger equations and a harmonic oscillator with time-dependent angular frequency is probably the only time-dependent problem solved by these transformations. In this work, we apply quantum canonical transformations to a harmonic oscillator in which both angular frequency and equilibrium position are time-dependent.

FAMILIES OF NONLINEAR TRANSFORMATIONS FOR ACCURATE EVALUATION OF WEAKLY SINGULAR INTEGRALS

  • BEONG IN YUN
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • v.27 no.3
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    • pp.194-206
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    • 2023
  • We present families of nonlinear transformations useful for numerical evaluation of weakly singular integrals. First, for end-point singular integrals, we define a prototype function with some appropriate features and then suggest a family of transformations. In addition, for interior-point singular integrals, we develop a family of nonlinear transformations based on the aforementioned prototype function. We take some examples to explore the efficiency of the proposed nonlinear transformations in using the Gauss-Legendre quadrature rule. From the numerical results, we can find the superiority of the proposed transformations compared to some existing transformations, especially for the integrals with high singularity strength.

SOME RESULTS RELATED TO NON-DEGENERATE LINEAR TRANSFORMATIONS ON EUCLIDEAN JORDAN ALGEBRAS

  • K. Saravanan;V. Piramanantham;R. Theivaraman
    • Korean Journal of Mathematics
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    • v.31 no.4
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    • pp.495-504
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    • 2023
  • This article deals with non-degenerate linear transformations on Euclidean Jordan algebras. First, we study non-degenerate for cone invariant, copositive, Lyapunov-like, and relaxation transformations. Further, we study that the non-degenerate is invariant under principal pivotal transformations and algebraic automorphisms.

Regularity of a Particular Subsemigroup of the Semigroup of Transformations Preserving an Equivalence

  • Rakbud, Jittisak
    • Kyungpook Mathematical Journal
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    • v.58 no.4
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    • pp.627-635
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    • 2018
  • In this paper, we use the notion of characters of transformations provided in [8] by Purisang and Rakbud to define a notion of weak regularity of transformations on an arbitrarily fixed set X. The regularity of a semigroup of weakly regular transformations on a set X is also investigated.

ON A CHARACTERIZATION OF SECURE TRINOMIALS ON ℤ2n

  • Rhee, Min Surp
    • Journal of the Chungcheong Mathematical Society
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    • v.29 no.4
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    • pp.573-584
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    • 2016
  • Invertible transformations over n-bit words are essential ingredients in many cryptographic constructions. Such invertible transformations are usually represented as a composition of simpler operations such as linear functions, S-P networks, Feistel structures and T-functions. Among them T-functions are probably invertible transformations and are very useful in stream ciphers. In this paper we will characterize a secure trinomial on ${\mathbb{Z}}_{2^n}$ which generates an n-bit word sequence without consecutive elements of period $2^n$.

EVALUATION OF SINGULAR INTEGRALS BY HYPERBOLIC TANGENT BASED TRANSFORMATIONS

  • Yun, Beong-In
    • Journal of the Korean Mathematical Society
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    • v.48 no.1
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    • pp.133-146
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    • 2011
  • We employ a hyperbolic tangent function to construct nonlinear transformations which are useful in numerical evaluation of weakly singular integrals and Cauchy principal value integrals. Results of numerical implementation based on the standard Gauss quadrature rule show that the present transformations are available for the singular integrals and, in some cases, give much better approximations compared with those of existing non-linear transformation methods.

QUADRATIC TRANSFORMATIONS INVOLVING HYPERGEOMETRIC FUNCTIONS OF TWO AND HIGHER ORDER

  • Choi, June-Sang;Rathie, Arjun K.
    • East Asian mathematical journal
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    • v.22 no.1
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    • pp.71-77
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    • 2006
  • By applying various known summation theorems to a general transformation formula based upon Bailey's transformation theorem due to Slater, Exton has obtained numerous and new quadratic transformations involving hypergeometric functions of order greater than two(some of which have typographical errors). We aim at first deriving a general quadratic transformation formula due to Exton and next providing a list of quadratic formulas(including the corrected forms of Exton's results) and some more results.

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LORENTZIAN SURFACES WITH CONSTANT CURVATURES AND TRANSFORMATIONS IN THE 3-DIMENSIONAL LORENTZIAN SPACE

  • Park, Joon-Sang
    • Journal of the Korean Mathematical Society
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    • v.45 no.1
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    • pp.41-61
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    • 2008
  • We study Lorentzian surfaces with the constant Gaussian curvatures or the constant mean curvatures in the 3-dimensional Lorentzian space and their transformations. Such surfaces are associated to the Lorentzian Grassmannian systems and some transformations on such surfaces are given by dressing actions on those systems.