• Proceedings of the Computational Structural Engineering Institute Conference
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• 2009.04a
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• pp.412-415
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• 2009

본 논문에서는 등기하 해석법을 이용하여 설계 의존형 하중조건을 갖는 구조물에 대한 형상 최적설계 를 수행하였다. 유한요소 기반 형상 최적설계는 설계영역 매개화에 어려움이 있으나 등기하 해석법은 NURBS 기저 함수와 조정점을 이용함으로써 기하학적 표현이 용이하다는 장점을 가지고 있다. 기하학적으로 정확한 모델은 응답 및 설계민감도 해석에 사용되며, 설계구배 기반의 최적화에 있어서 중요한 역할을 한다. 하중조건이 설계영역의 변화에 따라 변하는 최적설계 문제에서 경계에서 설계민감도가 부정확한 경우, 설계공간에서 최적설계가 균일한 수렴성을 갖기 어렵다. 즉 유한요소법을 이용한 형상 최적설계에서 설계 의존형 하중조건을 갖는 문제를 푸는 경우, 최적설계를 진행할 때 변하는 경계의 부정확성 때문에 정확한 설계민감도를 얻기가 어려운 점이 있다. 본 논문에서는, 엄밀한 기하형상을 표현하는 등기하 설계민감도를 활용한 형상 최적설계 기법이 설계 의존형 하중조건을 갖는 문제에서 좋은 결과를 제시함을 확인하였다.

• The korean journal of orthodontics
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• v.38 no.1
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• pp.13-30
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• 2008

Objective: The objective of this study was to evaluate the displacement pattern and the stress distribution of the finite element model 3-D visualization during symphyseal widening according to the osteotomy position, osteotomy type, and distraction device. Methods: The kinds of distraction devices used were tooth-borne type, hybrid type, bone-borne type and tooth-borne type $30^{\circ}$ angulated, and the kinds of osteotomy design were vertical osteotomy line between the central incisors and step osteotomy line through the symphysis. Results: All reference points of the mandible including the condyles were displaced laterally irrespective of the osteotomy position, osteotomy method and distraction device. The anteroposterior or vertical displacements showed small differences between the groups. The widening pattern of the osteotomy line in the tooth-borne type of device was v shaped, and that of bone-borne type was a reverse v shape. However, the pattern in the hybrid type was parallel. The lateral displacement of the mandibular angle by the bone-borne device was more remarkable than the other types of devices. The displacement by the $30^{\circ}$ angulated tooth-borne type was different between the left and right sides in both the transverse and anteroposterior aspects. Conclusion: The design of the distraction devices and osteotomy line can influence the displacement pattern and the stress distribution during mandibular symphyseal distraction osteogenesis procedures.

• Journal of The Korean Association For Science Education
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• v.25 no.5
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• pp.541-546
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• 2005

In order to suggest instructional strategy and learning guidance in science education, the purpose of this study was to classify middle school students by learning style and then examine student's science process skills via those learning styles. The Student Learning Style Questionnaire (SLSQ) and the Test of Science Process Skills (TSPS) were given to 340 ninth graders. Their learning styles were classified into three categories, that were divided into two opposing types: independent/ dependent, collaborative/ competitive, and participant/ avoidant. The results showed the following : 1) Students of the dependent, collaborative, and participant type out numbered ones of the independent, competitive, and avoidant type. 2) Gender differences showed that male students of the competitive, participant, dominant type totalled more than the female students of the collaborative, avoidant type. Furthermore, 3) For students of the independent, competitive, participant type, science process skills were higher than those of the dependent, collaborative, avoidant type.

• The Monthly Diabetes
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• s.192
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• pp.8-11
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• 2005

인슐린 주사가 반드시 필요한 당뇨병으로 소아연령으로 소아연령에서 발병되는 당뇨병의 대다수는 제1형 당뇨병이다. 자가 면역기능에 의해 인슈린을 생성하는 췌장의 도세포가 파괴되어 발병하고 대부분자가 항체가 나타나고 일부는 자가 항체가 발견되지 않는 경우도 있으며 소수에서는 초기에 인슐린의 비의존형의 양상을 보이다가 점차 인슐린 의존형으로 나타나는 경우도 있다.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.3
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• pp.521-526
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• 2002

A number of experimental and epidemiological studies have implicated that antiestrogenic effects of estrogen-like compounds in legumes and plant seeds are responsible for lowering breast cancer risk in human. However, few studies have been conducted to illustrate the possible chemopreventive effects of Korean traditional food materials. This study was performed to determine the cytotoxic and apoptotic effects of yellow soybeans, black soybeans and brown rice extracts on hormone-dependent and hormone-independent human breast cancer cells. Methanol-or acetone-soluble fractions of soybeans or brown rice were incubated with hormone-dependent cells (MCF-7) or hormone-independent cells (MDA-MB-231). Cell cytotoxicity was measured by MTT assay at 24, 48 and 72 hrs of incubation. Apoptotic effects of these extracts toward breast cancer cells were also determined at 48 hrs of incubation by measuring DNA fragmentation. Results indicated that the acetone-soluble fraction of brown rice exerted strongest cytotoxic effect on MCF-7 ceIls, although other fractions also reduced the number of viable MCF-7 cells after 48 hrs of incubation. Both acetone and methanol soluble fractions of all samples exerted a significant cytotoxicity towards MDA-MB-231 cells after 24 hrs of incubation, and acetone and methanol soluble fractions of brown rice were especially effective in these cells. At 48 hrs of incubation, methanol fractions of all three samples induced apopotosis of MDA-MB-231 cells. These results indicate methaol or acetone soluble fractions of yellow soybeans, black soybeans and brown rice induce cytotoxicity in both hormone-dependent and hormone-independent breast cancer cells. Therefore, possible mechanisms of cell cytotoxicity do not necessarily include antiestrogenic effects of soybean or brown rice extract. A possible anticarcinogenic effect of brown rice methanol-soluble fraction may mediated through their apoptotic effect. Further studies are requried to elucidate responsible compounds and mechanisms involved in observed anticarcinogenesis.

• Journal of the Korean Society for Library and Information Science
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• v.36 no.2
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• pp.231-241
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• 2002

In Web-based libraries, their RRS(Ready Reference Sites) provide their users with various web documents. And their users prefer finding web documents easily, rapidly and accurately Focused on their preference, Web designers or librarians working with the RRS should design the access path simply and conveniently. Concerning the design of the RRS in the Web-based library, 216 kinds of alternatives are identified as the result of the study When Web designers or librarians will improve or design their RRS, some of these alternatives might be helpful as the primary sources.

• Korean Journal of Social Welfare Studies
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• v.45 no.3
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• pp.71-95
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• 2014

The purpose of this study is to examine the effects of household income types and sources on the depressions and self-respect of the old aged. Although household income types and sources are supposed to be important to the mental health of the old aged as well as income level, there have been little policy interests to them. This study analyze the relationship between the household income types & sources and the mental health of the old aged, using the 8th data from the Korean Welfare Panel Study. Major findings are as follows. First, we find that there are considerable variations in the household income sources composition among the old aged, and that types of household income are related to the individual and family features of the old aged. Second, the results of regression analyses show that the household income types are associated with the depression and self-respect of the old aged. And, we find that some income sources affects the mental health of the old aged. The results of this study suggest that there should be policy attentions to the mental health effects of the household income sources so as to increase the adequacy of the income security system for the aged in Korea.

• Journal of Korea Game Society
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• v.20 no.1
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• pp.23-32
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• 2020

This study was attempted to investigate the factors that influence on problematic smartphone use and life satisfaction by smartphone usage type. A total of 25,465 people were used for the analysis and analyzed using the R (3.6.1) program. According to the data analysis, problematic smartphone use occurred in the form of leisure activity seeking and information seeking type. On the other hand, the communication type reduced problematic smartphone use. The type of smartphone use that had the greatest influence on life satisfaction was communication type The longer the smartphone use time and the higher the problematic smartphone use, the more negatively the life satisfaction.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.512-515
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• 2010

본 논문에서는 등기하 해석법을 이용하여 설계의존형 하중조건을 갖는 구조물에 대한 형상 최적설계를 수행하였다. 유한요소법 기반 형상 최적설계는 CAD 모델과 해석 모델의 차이로 인해, 설계영역 매개변수화에 어려움이 있다. 등기하 해석법은 CAD 모델과 동일한 NURBS 기저 함수와 조정점을 해석에 이용함으로써 설계의 기하학적 변화를 해석모델에 직접적으로 표현할 수 있는 장점을 가진다. 하중조건이 설계 영역이 변화함에 따라 변하는 최적설계 문제의 경우, 정확한 설계 영역 표현은 법선 벡터, 즉 변화하는 하중의 방향과 곡률과 같은 고차항의 정보를 정확하게 표현할 수 있고, 따라서 목적함수를 최소 또는 최대화시키는 최적의 해로 이끌어 낸다. 유한요소법 또는 밀도법을 이용한 형상 최적설계에서 설계의존형 하중조건을 갖는 구조물의 문제를 푸는 경우, 최적설계가 진행됨에 있어 변화하는 경계의 부정확성 때문에 정확한 설계민감도를 얻기가 어려운 점이 있다. 본 논문에서는, 수치 예제를 통해 등기하 해석 기반의 형상 최적설계 방법론이 설계의존형 하중조건을 갖는 구조물 문제에서 수월성을 가짐을 확인하였다.

• Journal of Welding and Joining
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• v.14 no.1
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• pp.38-46
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• 1996

High temperature low cycle fatigue crack growth behavior is investigated over a range of two temperatures and various frequencies in SUS 304 stainless steel. It is found that low frequency and temperature can enhance time-dependent crack growth. With high temperature, low frequency and long crack length, ${\Delta}J_c/{\Delta}J_ f$, the ratio of creep J integral range to fatigue J integral range is increased and time-dependent crack growth is accelerated. Interaction between ${\Delta}J_f$ and ${\Delta}J_c$ is occured at high frequency and low temparature and ${\Delta}J_c$, creep J integral range is fracture mechanical parameter on transition from cycle-dependent to time dependent crack growth in creep temperature region.