• Korean Journal of Child Studies
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• v.30 no.4
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• pp.69-85
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• 2009

The purpose of this study was to identify developmental trajectories of externalizing problems in preschoolers and to investigate dimensions of temperament and parental behaviors associated with trajectory groups. Subjects were 180 3- to 5-year-old preschoolers (96 males, 84 females) in the metropolitan area of Seoul. They were assessed three times at 5 month intervals over a one year period. Teachers reported on children's behavior problems, and parents reported on children's temperaments. Latent Growth Curve Modeling Analysis with cohort sequential design revealed externalizing behaviors gradually decreased between 3 and 6. At the 6-year-old level externalizing behaviors were associated with high novelty seeking temperament. The results were discussed in terms of the importance of longitudinal research in developmental psychopathology.

• Proceedings of the Korean Society for Quality Management Conference
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• 2010.04a
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• pp.345-350
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• 2010

2009년부터 도입된 근로소득 장려세제(EITC)와 가장 밀접한 관계가 있을 것으로 예상되는 기초생활 보장제도를 고려하고 근로소득 장려세제의 수급요건에 적합한 수급 세대규모와 상관분석 등을 통해 영향 요소를 선정하고 영향 요소를 예측하여 향후 근로소득 장려세제의 수급 규모나 필요 예산을 예측할 수 있는 시스템을 개발하였다. 예측에는 시계열 분석과 사회제도 성장에 적합한 로지스틱곡선 등을 이용하였다. 본 연구에서 제안된 시스템은 향후 제도에 따른 사회적 영향 예측과 제도 개선에 필요한 의사결정을 전략적으로 지원할 수 있을 것으로 기대한다.

• Journal of Ocean Engineering and Technology
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• v.12 no.3 s.29
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• pp.60-67
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• 1998

In this study, the J-Resistance Curve and material tearing modulus of SA508-C3 steel, which is one of the used nuclear pressure vessel steel, are measured ar room temperature, $200^{circ}C$ and $300^{circ}C$ according to load ratio analysis and ASTM E813, ASTM E1152, respectively. It is observed that J-R curve and Tmat value decrease as the temperature level increase. Applicability of $T_j$ proposed by Paris et al as instability parameter for ductile material is investigated. It is concluded that results are the $T_j$ parameter may be used as a crack instability parameter.

• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.2014-2016
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• 2002

Liquid crystal displays(LCDs)의 스위칭 소자로써 thin film transistors(TFTs)를 적용하기 위해서 저온 공정이 가능하도록 molybdenum 금속을 게이트에 사용하여 저온 다결정 TFTs 소자를 제작하였다. 또한, 채널 길이 방향으로 결정을 성장시켜 결정립이 큰 다결정 실리콘을 얻을 수 있는 sequential lateral solidification(SLS) 결정화 방법을 사용하였다. SLS-TFT 소자를 $2{\mu}m$에서 $20{\mu}m$까지의 다양한 채널 길이와 폭으로 제작한 후 각 소자들의 I-V 특성 곡선과 소자의 물성 분석을 위해 필요한 변수들을 구하여 이들의 전기적인 특성을 비교, 분석하였다. 제작된 소자들로부터 측정된 이동도는 $100{\sim}400Cm^2$/Vs, on/off 전류비는 약 $10^7$, off-state 전류는 약 $100{\times}10^{-12}A$로 대체적으로 우수한 특성을 보였다.

• Proceedings of the Korea Water Resources Association Conference
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• 2004.05b
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• pp.323-327
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• 2004

우리나라의 경우 짧은 자료기간으로 인해 지점빈도해석에 의한 확률강우량 추정시 불확실성이 커지는 문제가 있어 지역빈도해석의 적용이 필요하다. 본 인구에서는 지역빈도해석 기법의 하나인 FORGEX 기법을 우리나라 강우자료에 적용하였다. 전국의 82개 기상청 산하 관측지점의 자료로부터 지속기간별 연최대 강우 자료를 추출하였으며, FORGEX 기법의 절차애 따라 확률강우량을 계산하고자 하는 지점을 중심으로 네트워크를 구성하였다 Netmax 계열을 이용하여 긴 재현기간에 내한 안정된 확률강우량을 추정할 수 있는 성장곡선을 유도할 수 있었다.

• Korean Journal of Computational Design and Engineering
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• v.12 no.5
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• pp.354-365
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• 2007

We present novel methods to generate a sequence of shapes that represents the pattern of morphological development or transformation of Bezier curves. The presented methods utilize the intrinsic geometric structures of a Bezier curve that are derived from rib and fan decomposition (RFD). Morphological development based on RFD shows a characteristic pattern of structural growth of a Bezier curve, which is the direct consequence of development path defined by fans. Morphological transformation based RFD utilizes development patterns of source and target curves to mimic the theory of evolutionary developmental biology: although the source and target curves are quite different in shapes, we can easily find similarities in their younger shapes, which makes it easier to set up feature correspondences for blending them. We also show that further controls on base transformation for intensity of feature blending, and extrapolation can compensate the immaturity of blended curves. We demonstrate the experimental results where transformation patterns are smoother and have unique geometric style that cannot be generated using conventional methods based on multi-linear blending.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.4
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• pp.873-882
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• 1990

본 연구에서는 작은 크랙이 중앙 크랙선단 주위에 대칭으로 배치 분포되어 있 는 유한 평판의 경우에 대한 것으로, 우선 균일분포하중을 받는 정방형판에 분포크랙 이 있는 경우 분포크랙의 위치에 따른 중앙 크랙 선단에서의 응력확대계수의 변화를 유한요소법으로 해석하여 등응력확대계수 곡선들로 나타냈다. 그리고 크랙들 사이의 상호 간섭에 의해 일어나는 소성영역도 고려하여 그 안정성을 검토하여 보았는데, 특 히 크랙들이 서로 가까와 지면 그 크랙들 간에 상호간섭이 커져 소성영격이 크랙선단 주위에 크게 발생되므로써 크랙들은 쉽게 연결되고 합체로 인한 크랙성장이 되어 파괴 됨을 예측할 수 있고 중앙 크랙선단 주위의 분포크랙의 위치에 따른 소성영역 변화도 유한요소법으로 해석하여 도식적으로 나타냈다.

• IE interfaces
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• v.14 no.2
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• pp.190-197
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• 2001

Growth curves including Logistic and Gompertz functions are widely used in forecasting the market demand. To estimated the parameters of those functions, we use the non-linear least square method. However, it is difficult to set up the starting points for each parameter. If a wrong starting point is selected, the result reveals the local optimum or does not converge to a certain value. The purpose of this paper is to resolve the problem of selecting a starting point. Especially, rescaling the market data using the national economic index make it possible to figure out the range of parameters and to utilize the grid search method. Applications to some real data are also included.

• Journal of the Korean Society of Safety
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• v.8 no.4
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• pp.183-188
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• 1993

Anthropometric characteristics and considerations of sex differences are essential for the correct design of ergonomic work spaces. This paper is concerned with longitudinal study on the physical growth in Korean youth. Three hundred eighty-seven subjects were selected from third year students of high schools, and their records on physical examination during the last twelve years were surveyed by longitudinal method. For boys and girls, this study investigated the anthropometric characteristics of physical structure and the shape of physical growth. The result showed that the physical growth spurt of girl occurred earlier than that of boy. Also, by regression analysis, the third-order polynomial function was suitable for the growth curves of stature and weight, and there were significant sex differences in the fitted curves.

• Journal of Korea Multimedia Society
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• v.19 no.8
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• pp.1626-1635
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• 2016

This study examines whether online game motivation, with social and expedition needs, are associated with the degree of loneliness among young adolescents. Using data from a survey of 2014 elementary-, middle- and high-school students in South Korea, a three-wave online survey was conducted to collect data from online players. Two latent growth cause-and-effect models were developed to test whether online game motivation influences degree of loneliness. Results showed that both social and expedition needs are positively associated with loneliness. This study contributes to the knowledge of the underlying needs for a player with loneliness and also highlights the social and expedition needs as potential therapeutic factors.