• 대한수학회논문집
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• 제32권1호
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• pp.165-173
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• 2017

In this paper, we prove that the automorphism group of a quasi-homogeneous properly convex affine domain in ${\mathbb{R}_n}$ acts transitively on the set of all the extreme points of the domain. This set is equal to the set of all the asymptotic cone points coming from the asymptotic foliation of the domain and thus it is a homogeneous submanifold of ${\mathbb{R}_n}$.

• 호남수학학술지
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• 제41권3호
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• pp.595-607
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• 2019

We consider quasigroups $Q({\Gamma})$ obtained as certain double covers of the symmetric group $S_3$ of degree 3, for directed graphs ${\Gamma}$ on the vertex set $S_3$. We completely characterize the strong compatibility of elements of $Q({\Gamma})$ for any quasigroup nonuniform homogeneous space of degree 4. For such homogeneous spaces, we classify all the strong and weak compatibility graphs of $Q({\Gamma})$.

• 한국대기환경학회지
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• 제13권1호
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• pp.51-63
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• 1997

Total suspended particulate matters in the ambient air were analyzed for eight chemical elements (Ca, Co, Cu, Fe, Mn, Pb, Si, and Zn) using an x-ray fluorescence spectrometry (XRF) at the Kyung Hee University - Suwon Campus during 1989 to 1994. To use these data as basis for source identification study, membership of each sample was selected to represent one of the well defined sample groups. The data sets consisting of 83 objects and 8 variables were initially separated into two groups, fine (d$_{p}$<3.3 ${\mu}{\textrm}{m}$) and coarse particle groups (d$_{p}$>3.3 ${\mu}{\textrm}{m}$). A hierarchical clustering method was examined to obtain possible member of homogeneous sample classes for each of the two groups by transforming raw data and by applying various distances. A disjoint principal component analysis was then used to define homogeneous sample classes after deleting outliers. Each of five homogeneous sample classes was determined for the fine and the coarse particle group, respectively. The data were properly classified via an application of logarithmic transformation and Euclidean distance concept. After determining homogeneous classes, correlation coefficients among eight chemical variables within all the homogeneous classes for calculated and meteorological variables (temperature. relative humidity, wind speed, wind direction, and precipitation) were examined as well to intensively interpret environmental factors influencing the characteristics of each class for each group. According to our analysis, we found that each class had its own distinct seasonal pattern that was affected most sensitively by wind direction.ion.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1999년도 가을 학술발표회 논문집
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• pp.3-44
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• 1999

This paper discusses the lateral behavior of single and group piles in homogeneous and non-homogeneous(two layered) soil. In the single pile, the model tests were conducted to investigate the effects on ratio of lower layer height to embedded pile length, ratio of soil modules of upper layer to lower layer, boundary rendition of pile head and tip, embedded pile length, pile construction condition, ground condition with saturate and moisture state in Nak-Dong river sand. Also, in the group pile, the model tests were to investigate the effects on spacing-to-diameter ratio of pile, pile array, ratio of pile spacing, boundary condition of pile head and tip, eccentric load and ground condition. The maximum bending moment and deflection induced in active piles were found to be highly dependent on the relative density, pile construction condition, boundary condition of pile head and tip. Based on the results obtained, it was found that the decrease of lateral bearing capacity in saturated sand was in the range of 31% - 53% as compared with the case of dry sand. Also, in the group pile, a spacing-to-diameter of 6.0 seems to be large enough to eliminate the group effect for the case of relative density of 61.8%, and 32.8%, and then each pile in such a case behaves essentially the same as a single pile. In this study, the program is developed by using the modified Chang method which used p - y method and the exact solution of governing equation of pile and it can be used to calculate the deflection, bending moment and soil reaction with FDM in non-homogeneous soil. In comparing the modified Chang method with field test results, the predict results shows better agreement with measured results in field tests.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 가을 학술발표회 논문집
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• pp.253-260
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• 2000

Pile foundations have been widely used in civil engineering construction for many years. Structures subjected to large lateral loads usually have pile foundations as shallow foundations cannot sometimes support the moments on these structure. The purpose of this paper is to propose the p - multiplier factor (P$\sub$M/) based on the characteristics of behavior of laterally loaded group pile in homogeneous sand. For this, a series of model tests are performed and the composite analytical method proposed by author is used to the propose P$\sub$M/. Based on the model test results of the large number of laterally loaded group piles, p - multiplier factors for homogeneous sand are proposed by back analysis under various condition of soil density, spacing-to-diameter ratio of pile, number of pile, and spacing-to-diameter of pile. P - multiplier approach provides a simple but sufficient tool for characterizing the shadowing group effects of laterally loaded group pile.

• 대한수학회지
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• 제39권1호
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• pp.61-75
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• 2002

Under the cancellation property and the Lipschitz condition on kernels, we prove that the Marcinkiewicz integrals defined on a homogeneous group H are bounded from $H^1$(H) to $L^1$(H), from $L_{c}$ $^{\infty}$(H) to BMO (H), and from $L^{p}$ (H) to $L^{p}$ (H) for 1 < p < $\infty$ assuming the $L^{q}$ -boundedness for some q > 1.for some q > 1.

• 대한수학회보
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• 제49권5호
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• pp.1101-1129
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• 2012

We study the geometry of the images of 1-dimensional homogeneous submersions for each of the model spaces X of the eight 3-dimensional geometries. In particular, We shall calculate the group of isometries and the curvatures of the base surfaces for each of the model spaces of 3-dimensional geometries, with respect to every closed subgroup of the isometries of X acting freely.

• 대한수학회지
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• 제55권5호
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• pp.1235-1255
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• 2018

We provide definitions for the helicoidal Killing field and the helicoid in arbitrary three-manifolds, and investigate helicoids and ruled minimal surfaces in homogeneous three-manifolds, mainly in $SL_2{\mathbb{R}}$ and Sol(3). In so doing we finish our classification of ruled minimal surfaces in homogeneous three-manifolds with the isometry group of dimension 4.

• 한국광학회지
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• 제28권6호
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• pp.327-333
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• 2017

이 연구의 목적은 초등학교 6학년 '렌즈의 이용' 단원 학습에서 나타나는 모둠별 언어적 상호작용의 특성을 파악하는 것이다. 이 연구를 위해 초등학교 6학년 한 학급을 학업성취도에 따라 상, 중, 하 모둠으로 구성하고 6차시의 수업을 진행하였다. 학생들 사이의 상호작용을 분석하기 위해 모든 수업을 녹음하였으며, 전사된 자료는 언어적 상호작용 분석틀을 이용하여 분석하였다. 연구 결과, 상위 수준은 의견제시의 빈도가 높았으나, 과제완수를 위한 부정적인 언어적 상호작용이 많이 일어났다. 중 모둠은 다른 사람의 의견을 듣기 보다는 자신의 의견을 제시하는데 더 적극적이었다. 하 모둠은 의견제시가 많았음에도 불구하고, 동료의 의견을 존중하지 않거나 동료를 설득시키는 능력이 부족하여 결론 도출에 어려움을 겪었다. 따라서 모둠구성 시 간단한 탐구나 수용의 범위가 넓은 활동에서는 동질적인 모둠 구성이 좋으며, 과학적 개념 및 지식 이해를 위주로 하는 활동에서는 이질적인 모둠 구성이 더욱 효과적이라 할 수 있다.

• 디지털융복합연구
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• 제17권12호
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• pp.59-65
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• 2019

본 연구는 비전공생 대상의 프로그래밍 교육에서 중·소규모의 학생 수로 구성된 학습에서도 학습 성취도를 높일 수 있는 방안으로 동질적 학습 집단 구성의 필요성을 제안하기 위하여 진행되었다. 학부전공별 수업이 진행되고 있는 현실에서 이러한 집단구성이 학습자를 동질 집단으로 분류할 수 있는 요인인지 살펴보았다. 학습내용의 난이도는 동질 집단을 분류하는 요인에 영향을 미칠 것으로 보고, 난이도가 쉬운 중간성취도와 기말성취도를 나누어 요인을 분석하였다. 또한 난이도와 상관없이 학기내 지속적 학습 의지를 갖는데 영향을 끼치는 요인을 분석하기 위해 두 성적간의 차이에 영향을 미치는 요인도 살펴보았다. 학습자의 성별과 학부전공은 학업성취도에 유의미한 영향을 미치지 않았다. 현재 학부전공별로 프로그래밍 수업이 진행되고 있는 수업환경을 재고해볼 필요가 있을 것으로 보인다. 난이도가 쉬운 학습내용의 학업성취도에는 학습자의 개인적동기가 영향을 미쳤고, 난이도가 어려운 학습내용의 학업성취도와 성취도의 유지에는 수행자기효능감이 영향을 미치는 것으로 나타났다.