• 한국경영과학회지
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• 제42권1호
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• pp.19-28
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• 2017

Moments of stationary intervals and those of the counting process can be used for moment fittings of the point processes. As for the Markovian arrival processes, the moments of stationary intervals are given as a polynomial function of parameters whereas the moments of the counting process involve exponential terms. Therefore, moment fittings are more complicated with the counting process than with stationary intervals. However, in queueing network analysis, cross-correlation between point processes can be modeled more conveniently with counting processes than with stationary intervals. A Laplace-Stieltjies transform of the stationary intervals of MAP (3)s is recently proposed in minimal number of parameters. We extend the results and present the Laplace transform of the counting process of MAP (3)s. We also show how moments of the counting process such as index of dispersions for counts, IDC, and limiting IDC can be used for moment fittings. Examples of exact MAP (3) moment fittings are also presented on the basis of moments of stationary intervals and those of the counting process.

• 한국소음진동공학회논문집
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• 제21권7호
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• pp.622-628
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• 2011

The purpose of this study was to analyze the vibro-acoustic characteristics of a stiffened rectangular plate at high frequencies. The stiffeners attached along the plate surface were assumed to have rotational and translational stiffness and inertia. The harmonic response of the stiffened plate were predicted and compared using the Rayleigh-Ritz method with two different trial functions - polynomial and beam functions. The variation of the spatially averaged mean square velocity and the modal characteristics with the number of stiffeners were obtained. The use of the beam function ensured fast convergence which was essential for analyzing the high frequency vibration responses. Using the calculated modal characteristics and the Rayleigh-integral, the radiated sound power was predicted, and the effects of stiffeners were investigated. The proposed model can be applied to study optimal layout of stiffeners for minimal noise generation of the stiffened structures.

• 정보보호학회논문지
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• 제15권2호
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• pp.105-111
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• 2005

GF(2) 셀룰라 오토마타가 비트단위로 데이터가 처리되는데 비하여 GF(2P) 셀룰라 오토마타는 비트단위 이상의 단위로 데이터론 처리할 수 있다. 본 논문에서는 GF(2p) 위에서의 유한체 성질을 이용하여 한 개의 트리로 구성되는 GF(2P)위에서의 nongroup 셀룰라 오토마타의 상태들의 움직임을 분석한다. 또한 기력경로를 이용하여 GF(2P)위에서 선형 SACA의 상태전이 그래프를 구성하는 방법과 선형 SACA의 상태전이 그래프를 이용하여 비선형인 여원 SACA의 상태전이 그래프를 구성하는 방법을 제시한다.

• 품질경영학회지
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• 제48권2호
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• pp.269-282
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• 2020

Purpose: The practical design for experiments with mixtures of q components is consisted in the four types of design points, vertex, center of edge, axial, and center points in a (q-1)-dimensional simplex space. We propose a sequential method for the successful construction of the design space in Quality by Design (QbD) by allowing the different number of replicates at the four types of design points in the practical design when the quadratic canonical polynomial model is assumed. Methods: To compare the mixture designs efficiency, fraction of design space (FDS) plot is used. We search for the practical mixture designs whose the minimal half-width of the tolerance interval per a standard deviation, which is denoted as d₂, is less than 4.5 at 0.8 fraction of the design space. They are found by adding the different number of replicates at the four types of the design points in the practical design. Results: The practical efficient mixture designs for the number of components between three and five are listed. The sequential method to establish a design space is illustrated with the two examples based on the simulated data. Conclusion: The designs with the center of edge points replications are more efficient than those with the vertex points replication. We propose the sample size of at least 23 for three components, 28 for four components, and 33 for the five components based on the list of efficient mixture designs.

• 대한수학회지
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• 제58권3호
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• pp.643-702
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• 2021

Fix ℤ/2 is the prime field of two elements and write 𝒜₂ for the mod 2 Steenrod algebra. Denote by GL_d := GL(d, ℤ/2) the general linear group of rank d over ℤ/2 and by ${\mathfrak{P}}_d$ the polynomial algebra ℤ/2[x₁, x₂, …, x_d] as a connected unstable 𝒜₂-module on d generators of degree one. We study the Peterson "hit problem" of finding the minimal set of 𝒜₂-generators for ${\mathfrak{P}}_d$. Equivalently, we need to determine a basis for the ℤ/2-vector space $$Q{\mathfrak{P}}_d:={\mathbb{Z}}/2{\otimes}_{\mathcal{A}_2}\;{\mathfrak{P}}_d{\sim_=}{\mathfrak{P}}_d/{\mathcal{A}}^+_2{\mathfrak{P}}_d$$ in each degree n ≥ 1. Note that this space is a representation of GL_d over ℤ/2. The problem for d = 5 is not yet completely solved, and unknown in general. In this work, we give an explicit solution to the hit problem of five variables in the generic degree n = r(2^t - 1) + 2^ts with r = d = 5, s = 8 and t an arbitrary non-negative integer. An application of this study to the cases t = 0 and t = 1 shows that the Singer algebraic transfer of rank 5 is an isomorphism in the bidegrees (5, 5 + (13.2⁰ - 5)) and (5, 5 + (13.2¹ - 5)). Moreover, the result when t ≥ 2 was also discussed. Here, the Singer transfer of rank d is a ℤ/2-algebra homomorphism from GL_d-coinvariants of certain subspaces of $Q{\mathfrak{P}}_d$ to the cohomology groups of the Steenrod algebra, $Ext^{d,d+*}_{\mathcal{A}_2}$ (ℤ/2, ℤ/2). It is one of the useful tools for studying these mysterious Ext groups.

• 한국의학물리학회지:의학물리
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• 제11권2호
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• pp.109-116
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• 2000

자궁경부암 환자의 방사선 조사시 고려하여야 할 사항 중 한가지는 결정 장기인 방광 및 직장의 부작용이다. 강내 고선량률 근접 치료시 방광과 직장의 흡수선량을 열형광량계 선량측정법을 이용하여 간접적으로 측정하였다 방광 및 직장의 부작용을 줄일 수 있는 방법이 제안되었다. 방사선 치료 후 예후관찰 중인 200명의 자궁경부암 환자의 자기공명 영상에서 자궁경부의 중심축에서 방광 및 직장 그리고 자궁벽의 두께를 측정하였다. 밀봉시킨 열형광량계를 오보이드의 팩킹거즈 위에 놓고 씨물레이션 필름 상에서 오보이드의 중심에서부터의 거리를 측정한 후 실제의 방광과 직장의 흡수선량을 계산하였다. 발표된 연구결과들에서 방광 및 직장의 최대 견딤선량을 계산하였고 고선량률 근접치료 1회당의 허용선량을 토대로 양방향의 팩킹두께를 알아냈다 방광과 직장방향의 최소의 팩킹두께는 각각 0.43 과 0.92 cm 이었다. 이 결과를 마이스버거 다항식을 이용한 계산결과와 비교하였다. 본 연구에서 제시한 방법이 임상에서 고선량률 근접 치료시 방광과 직장 같은 결정장기의 흡수선량을 평가하는 방법으로 사용되기를 바란다.