• 대한수학회논문집
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• 제13권4호
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• pp.817-823
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• 1998

In the present paper, we study conformal and projective Killing vector fields and infinitesimal Q-transformations on a quaternionic Kahlerian manifold, and prove that an infinitesimal conformal or projective automorphism in a compact quaternionic Kahlerian manifold is necessarily infinitesimal automorphism.

• 대한수학회지
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• 제39권1호
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• pp.91-102
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• 2002

Let M and N be CR manifolds with nondegenerate Levi forms of hypersurface type of dimension 2m ＋ 1 and 2n ＋ 1, respectively, where 1 $\leq$ m $\leq$ n. Let f : M longrightarrow N be a CR mapping. Under a generic assumption we construct a complete system of finite order for the infinitesimal deformations of f. In particular, we prove the space of infinitesimal deformations of f forms a finite dimensional Lie algebra.

• 충청수학회지
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• 제23권1호
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• pp.1-10
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• 2010

In this note, we investigate the infinitesimal generators of the transformation groups induced by the Fourier-Gauss and Fourier-Mehler transforms on white noise functionals.

• 대한수학교육학회지:학교수학
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• 제10권3호
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• pp.375-399
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• 2008

무한소는 현재 정적분 개념과 관련하여 교과서에서는 직접적인 역할을 하지 않고 있다. 그러나 정적분 개념에 대한 학생들의 이해를 조사한 선행 연구들을 보면 많은 학생들이 무한소를 이용하여 정적분을 이해하고 있다는 것을 보여주고 있다. 가르치지 않았음에도 불구하고 학생들이 무한소를 이용하여 정적분을 해석한다는 것은 정적분 자체 내에 무한소 해석을 촉진하는 구조적 요소가 있다고 가정할 수 있다. 이에 따라 본 논문에서는 정적분의 분할-합 과정에 대한 역사적 발달과정에서 무한소의 역할을 고찰하고, 그것을 바탕으로 하여 교수학적 시사점을 살펴보고자 한다. 그리고 이를 토대로 하여 우리나라 교과서 적분법 단원이 어떻게 무한소 해석을 유도하는지 그리고 학생들의 이해 방식은 어떠한지 살펴보았다. 그리고 이사의 논의를 종합하여 직관의 정련화 과정으로 정적분의 교수-학습과 관련하여 시사점을 제안하였다.

• Journal of the Korean Statistical Society
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• 제22권1호
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• pp.27-37
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• 1993

Since the analytic expression for a diagnostic in the logistic regression model is not available, one-step estimation is often used by a case-deletion point of view. In this paper, infinitesimal perturbation approach is used, and it is shown that the scale transformation of infinitesimal perturbation approach is eventually equal to the weighted perturbation of local influence approach and the replacement measure. Also, multiple cases deletion for the masking effect is considered.

• 대한수학회보
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• 제59권1호
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• pp.101-110
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• 2022

In this article, the notion of *-conformal Ricci soliton is defined as a self similar solution of the *-conformal Ricci flow. A Sasakian 3-metric satisfying the *-conformal Ricci soliton is completely classified under certain conditions on the soliton vector field. We establish a relation with Fano manifolds and proves a homothety between the Sasakian 3-metric and the Berger Sphere. Also, the potential vector field V is a harmonic infinitesimal automorphism of the contact metric structure.

• 비파괴검사학회지
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• 제13권1호
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• pp.21-28
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• 1993

If the infinitesimal delamination exists and the two waves can hardly be distinguished from each other on account of being much closer, we cannot measure the thickness of delamination by the time difference method. On this study, we calculated the thickness of infinitesimal delamination model by means of measuring echo height due to the deflection of material particles and utilized Newton Ring for optical measurement as a delamination model. From the result of Newton Ring expressed in the delamination model, we can calculate the infinitesimal delamination thickness up to $0.2{\sim}0.3{\mu}m$ due to the difference of acoustic impedance by the ratio of the echo height to the total reflection.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 춘계학술대회 논문집
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• pp.1139-1140
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• 2010

• 대한수학회논문집
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• 제9권3호
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• pp.629-639
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• 1994

Loewner ([13]) showend the semigroup of the real non-singular totally positive matrices is generated by itsinfinitesimal elements, that is,s the set of all Jacobi matrices with non-negative off-diagonal elements. In general, a semigroup is not completely recreated from the set of its infinitesimal elements. We extend Loewner's work and show that the semi-group of all invertible upper (or lower) triangular stochastic matrices is generated by the set of its infinitesimal elements.

• 대한수학회지
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• 제37권2호
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• pp.225-243
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• 2000

We explain the notion of complete system and how it naturally arises from the equivalence problem of G-structures. Then we construct a complete system of 3rd order for the infinitesimal CR automorphisms of CR manifold of nondegenerate Levi form.