• 한국수학교육학회지시리즈B:순수및응용수학
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• 제2권2호
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• pp.83-89
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• 1995

A Bayes estimator of the survival distribution function due to Susarla and Van Ryzin(1976) is used to estimate the mth moment of a survival time on the basis of censored observations in a random censorship model. Asymptotic normality of the estimator is proved using the functional version of the delta method.

• 충청수학회지
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• 제24권2호
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• pp.313-317
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• 2011

In this article, we consider an unbounded minimal graph $M{\subset}R^3$ which is contained in a slab. Assume that ${\partial}M$ consists of two Jordan curves lying in parallel planes, which is symmetric with the reflection under a plane. If the asymptotic behavior of M is also symmetric in some sense, then we prove that the minimal graph is itself symmetric along the same plane.

• 대한수학회지
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• 제58권5호
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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.

• 대한수학회지
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• 제59권5호
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• pp.1015-1045
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• 2022

Zagier introduced the term "strange identity" to describe an asymptotic relation between a certain q-hypergeometric series and a partial theta function at roots of unity. We show that behind Zagier's strange identity lies a statement about Bailey pairs. Using the iterative machinery of Bailey pairs then leads to many families of multisum strange identities, including Hikami's generalization of Zagier's identity.

• 대한전자공학회논문지TC
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• 제44권7호통권361호
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• pp.47-52
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• 2007

본 논문은 다중 셀 환경에서 MMSE 수신기를 가지는 MIMO MC-CDMA시스템의 출력 SINR을 점근적으로 분석한다. 단일 셀에서의 점근적 성능 분석이 다중셀 환경으로 확장 적용된다. 점근적 분석을 위한 Haar 유니터리 코드의 사용은 다른 셀로부터의 간섭성분이 대각성분들의 값이 다른 대각행렬로 나타나게 한다. 본 논문에서는 다른 셀의 코드 간섭 성분을 mean square측면에서 간섭의 전력으로 수렴함을 보이고, 셀간 간섭 성분이 주어질 때 점근적으로 특정 SINR값을 찾는다. 다중 셀에서의 거리에 따른 느린 페이딩을 로그노말 분포를 가정하여 구한 이론적인 비트오차 확률과 실험을 비교하여 비슷함을 보이고, 점근적 성능에 의한 데이터 전송 수율의 셀 반경에 따른 성능을 보인다.

• Structural Engineering and Mechanics
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• 제88권6호
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• pp.589-598
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• 2023

This article addresses the quasi-static analysis of time-dependent honeycomb sandwich plates with various geometrical properties based on the bending analysis of elastic honeycomb sandwich plates employing a time function with three unknown coefficients. The novel point of the developed method is that the responses of viscoelastic honeycomb sandwich plates under static transversal loads are clearly formulated in the space and time domains with very low computational costs. The mechanical properties of the sandwich plates are supposed to be elastic for the faces and viscoelastic honeycomb cells for the core. The Boltzmann superposition integral with the constant bulk modulus is used for modeling the viscoelastic material. The shear effect is expressed using the first-order shear deformation theory. The displacement field is predicted by the product of a determinate geometrical function and an indeterminate time function. The simple HP cloud mesh-free method is utilized for discretizing the equations in the space domain. Two coefficients of the time function are extracted by answering the equilibrium equation at two asymptotic times. And the last coefficient is easily determined by solving the first-order linear equation. Numerical results are presented to consider the effects of geometrical properties on the displacement history of viscoelastic honeycomb sandwich plates.

• Journal of the Korean Statistical Society
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• 제30권1호
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• pp.41-61
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• 2001

The minimum negative exponential disparity estimator(MNEDE), introduced by Lindsay(1994), is an excellenet competitor to the minimum Hellinger distance estimator(Beran 1977) as a robust and yet efficient alternative to the maximum likelihood estimator in parametric models. In this paper we define the negative exponential deviance test(NEDT) as an analog of the likelihood ratio test(LRT), and show that the NEDT is asymptotically equivalent to he LRT at the model and under a sequence of contiguous alternatives. We establish that the asymptotic strong breakdown point for a class of minimum disparity estimators, containing the MNEDE, is at least 1/2 in continuous models. This result leads us to anticipate robustness of the NEDT under data contamination, and we demonstrate it empirically. In fact, in the simulation settings considered here the empirical level of the NEDT show more stability than the Hellinger deviance test(Simpson 1989). The NEDT is illustrated through an example data set. We also define a goodness-of-fit statistic to assess adequacy of a specified parametric model, and establish its asymptotic normality under the null hypothesis.

• 한국연소학회지
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• 제13권1호
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• pp.23-30
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• 2008

An analytical expression for the turbulent burning velocity is derived from the asymptotic zone conditional transport equation at the leading edge. It is given as a sum of laminar and turbulent contributions, the latter of which is given as a product of turbulent diffusivity in unburned gas and inverse scale of wrinkling at the leading edge. It was previously shown that the inverse scale is equal to four times the maximum flame surface density in the wrinkled flamelet regime [1]. The linear behavior between $U_T$ and u' shows deviation with the inverse scale decreasing due to the effect of a finite flamelet thickness at higher turbulent intensities. DNS results show that $U_T/S^0_{Lu}$ may be given as a function of two dimensionless parameters, $u'/S^0_{Lu}$ and $l_t/\delta_F$, which may be transformed into another relationship in terms of $u'/S^0_{Lu}$, and Ka. A larger $l_t/{\delta}_F$ or a smaller Ka leads to a smaller scale of wrinkling, hence a larger turbulent burning velocity in the limited range of $u'/S^0_{Lu}$. Good agreement is achieved between the analytical expression and the turbulent burning velocities from DNS in both wrinkled and thickened-wrinkled flame regimes.

• 응용통계연구
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• 제17권2호
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• pp.269-280
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• 2004

본 연구를 통하여 순위를 이용한 선형회귀모형의 가정된 분포형태가 우리가 실질적으로 많이 접하게 되는 비대칭분포이면서 만일 가정된 분포가 오른쪽으로 늘어진 경우일 때에는, 본 논문에서 제안된 스코어의 가능한 한 0 보다 크고 1 보다 작은 r 및 1 보다 큰 s 를 선택 (0 〈 r 〈 1, s 〉 1) 하는 것이 윌콕슨 스코어보다 높은 효율성을 나타낸다. 이와 반대로 만일 가정된 비대칭분포가 왼쪽으로 늘어진 경우일 때에는, 제안된 스코어의 가능한 한 1 보다 큰 r 및 0 보다 크고 1 보다 작은 s 를 선택 (r 〉 1, 0 〈 s 〈 1) 하는 것이 윌콕슨 스코어보다 높은 효율성을 나타낸다. 아울러 바람직한 r 과 s 를 결정하기 위한 가정된 분포의 대칭성 검정기법도 제시한다.

• 한국태양에너지학회 논문집
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• 제36권3호
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• pp.9-16
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• 2016

This paper discusses a refined model for investigating the micro-mechanical behavior of beam-like structures, which are composed of various elastic moduli and complex geometries varying through the cross-section directions and are also periodically-repeated and heterogeneous along the axial direction. Following the previous work (Lee and Yu, 2011), the original three-dimensional static problem is first formulated in a unified and compact form using the concept of decomposition of the rotation tensor. Taking advantage of the smallness of the cross-sectional dimension-to-length parameter and the micro-to-macro heterogeneity, while also performing homogenization along the dimensional reduction simultaneously, the variational asymptotic method is rigorously used to construct a total energy function, which is asymptotically correct up to the second order. Furthermore, through the transformation procedure based on the pure kinematic relations and the linearized equilibrium equations, a generalized Timoshenko model is systematically established. For the purpose of dealing with realistic and complex geometries and constituent materials at the microscopic level, this present approach is incorporated into a commercial analysis package. A few examples available in literature are used to demonstrate the consistency and efficiency of this proposed model, especially for the structures, in which the effects of transverse shear deformations are significant.