• 제목/요약/키워드: integrals

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FURTHER LOG-SINE AND LOG-COSINE INTEGRALS

  • Choi, Junesang
    • 충청수학회지
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    • 제26권4호
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    • pp.769-780
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    • 2013
  • Motivated essentially by their potential for applications in a wide range of mathematical and physical problems, the log-sine and log-cosine integrals have been evaluated, in the existing literature on the subject, in many different ways. Very recently, Choi [6] presented explicit evaluations of some families of log-sine and log-cosine integrals by making use of the familiar Beta function. In the present sequel to the investigation [6], we evaluate the log-sine and log-cosine integrals involved in more complicated integrands than those in [6], by also using the Beta function.

집합치 쇼케이적분과 수렴정리에 관한 연구(II) (On set-valued Choquet integrals and convergence theorems(II))

  • 장이채;김태균;전종득
    • 한국지능시스템학회논문지
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    • 제12권4호
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    • pp.323-326
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    • 2002
  • 이 논문에서 구간 수의 값을 갖는 함수들의 쇼케이적분을 생각하고자 한다. 이러한 구간 수의 값을 갖는 함수들의 성질들을 조사하여 오토연속인 퍼지측도에 관련된 쇼케이적분에 대한 수렴성 정리를 증명한다.

분자계의 Overlap Integral의 계산의 Spherical Harmonics 전개방법의 응용 (Application of the Expansion Method for Spherical Harmonics for Computation of Overlap Integrals in Molecular System)

  • 안상운
    • 대한화학회지
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    • 제22권3호
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    • pp.117-127
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    • 1978
  • 두점 A와 B에 위치한 Slater원자궤도함수의 spherical harmonics부와 지름부를 기준점 A를 중심으로 전개하여 공통좌표상에 기술하였다. 이 Slater 원자궤도함수의 전개식을 사용하여 two center overlap integral의 기본식을 유도하였으며 이 기본식을 이용하여 $CH_4,\;H_2O,\;NH_3,\;C_2H_6$$PH_3$ 분자의 two center overlap integral을 계산하였을 때 이 값이 Mulliken의 값과 일치하였다.

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Some characterizations of a mapping defined by interval-valued Choquet integrals

  • Jang, Lee-Chae;Kim, Hyun-Mee
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • 제7권1호
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    • pp.66-70
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    • 2007
  • Note that Choquet integral is a generalized concept of Lebesgue integral, because two definitions of Choquet integral and Lebesgue integral are equal if a fuzzy measure is a classical measure. In this paper, we consider interval-valued Choquet integrals with respect to fuzzy measures(see [4,5,6,7]). Using these Choquet integrals, we define a mappings on the classes of Choquet integrable functions and give an example of a mapping defined by interval-valued Choquet integrals. And we will investigate some relations between m-convex mappings ${\phi}$ on the class of Choquet integrable functions and m-convex mappings $T_{\phi}$, defined by the class of closed set-valued Choquet integrals with respect to fuzzy measures.

Derivation of Analytic Formulas and Numerical Verification of Weakly Singular Integrals for Near-Field Correction in Surface Integral Equations

  • Rim, Jae-Won;Koh, Il-Suek
    • Journal of electromagnetic engineering and science
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    • 제17권2호
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    • pp.91-97
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    • 2017
  • An accurate and efficient evaluation for hypersingular integrals (HIs), strongly singular integrals (SSIs), and weakly singular integrals (WSIs) plays an essential role in the numerical solutions of 3D electromagnetic scattering problems. We derive analytic formulas for WSIs based on Stokes' theorem, which can be expressed in elementary functions. Several numerical examples are presented to validate these analytic formulas. Then, to show the feasibility of the proposed formulations for numerical methods, these formulations are used with the existing analytical expressions of HIs and SSIs to correct the near-field interaction in an iterative physical optics (IPO) scheme. Using IPO, the scattering caused by a dihedral reflector is analyzed and compared with the results of the method of moments and measurement data.

콤팩트 집합치 쇼케이적분에 관한 연구 (A note on compact set-valued Choquet integrals)

  • 장이채;김현미
    • 한국지능시스템학회논문지
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    • 제15권5호
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    • pp.588-592
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    • 2005
  • 퍼지측도와 관련된 폐집합치 쇼케이적분에 대해 장에 의해 연구되어 왔음을 알 수 있다. 본 논문에서는 콤팩트 집합치 함수의 쇼케이적분을 생각하고 이와 관련된 성질들을 조사한다. 특히, 구간치 함수 대신에 콤팩트 집합치 함수를 이용하여 콤팩트 집합치 쇼케이적분의 특성들을 조사한다.

Hyperfine Interaction Integrals for NMR Chemical Shifts in 5f Paramagnetic Systems

  • 이기학;이지영;김동희
    • Bulletin of the Korean Chemical Society
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    • 제18권4호
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    • pp.424-427
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    • 1997
  • To study the NMR chemical shift arising from the 5f-electron orbital angular momentum and the 5f-electron spin dipolar-nuclear spin angular momentum interactions, the evaluation of the hyperfine integrals has been extended to any pairs of SCF type 5f orbitals adopting a general method which is applicable to a general vector R, pointing in any direction in space. From the electronic wavefunctions for 5f orbitals expressed in common coordinate system, the radial part of the hyperfine interaction integrals are derived by translating the exponential part, r2 exp(-2βr), in terms of R, rN and the modified Bessel functions. The radial integals for 5f orbitals are tabulated in analytical forms. When two of the hyperfine integrals along the (100), (010), (001), (110), and (111) axes are calculated using the derived radial integrals, the calculated values for the 5f system change sign for R-values larger than R 0.35 nm. But the calculated values for the 4f systems change sign for R-values larger than R 0.20 nm.

Calculation of NMR Chemical Shift for a 3d$^1$ System in a Strong Crystal Field Environment of Tetrahedral Symmetry (1). Application of the Expansion Method for a Spherical Harmonics for Derivation of Overlap and the Dipole Moment Matrix Elements of $\mid$4p > Atomic Orbitals and Derivation of the Radial Integrals for the Hyperfine Interaction for $\mid$4p > Atomic Orbitals

  • Ahn, Sang-Woon;Kim, Dong-Hee;Choi, Chang-Jin
    • Bulletin of the Korean Chemical Society
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    • 제7권4호
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    • pp.299-304
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    • 1986
  • Master formulas for overlap integrals and the dipole moments involving |4p > atomic orbitals have been derived by the expansion method for spherical harmonics. The radial integrals for the hyperfine interaction have also been derived for |4p > atomic orbitals. The calculated values of the overlap integrals and dipole moment matrix elements by the expansion method for spherical harmonics for a hypothetical NO molecule are exactly in agreement with those of Mulliken's method. The radial integrals for the hyperfine interaction may be used to calculate the chemical shift for |4p > atomic orbitals.

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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    • 제27권3호
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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.