• Tribology and Lubricants
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• 제16권5호
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• pp.373-380
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• 2000

Finite element analysis is performed on the subsurface crack propagation in brittle materials due to sliding contact. The sliding contact is simulated by a rigid asperity moving across the surface of an elastic half-surface containing single and multiple cracks. The single crack, coplanar cracks and parallel cracks are modeled to investigate the interaction effects on the crack growth in contact fatigue. The crack location is fixed and the friction coefficients between asperity and half-space are varied to analyze the effect of surface friction on stress intensity factor for horizontal cracks. The crack propagation direction is predicted based on the maximum range of shear and tensile stress intensity factors. With a coplanar crack, the stress intensity factor was increased. However, with a parallel crack, the stress intensity factor was decreased. These results indicate that the interaction of a coplanar crack increases fatigue crack propagation, whereas that of a parallel crack decreases it.

• 한국초등과학교육학회지:초등과학교육
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• 제39권3호
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• pp.323-337
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• 2020

To achieve effective learning, knowledge must be shared and developed through interaction with peer learners. Therefore, science education emphasizes small group inquiry activities that solves tasks through the interaction of members. The effect of small group inquiry activities depends on how to compose small groups. The way in which a group is composed is a very important factor for improving interaction. In particular, it has been reported that the gender of peer is a very important factor in the interaction between students in the composition of small groups. Meanwhile, studies are being conducted on the types and stability of verbal interactions in small group inquiry activities using social network analysis. The purpose of this study is to analyze the types and stability of verbal interaction types and stability according to gender-grouping in elementary school students' small group activities using social network analysis. To this end, 60 5th graders in elementary school were conducted with different gender in the composition of the group of male, female and mixed-gender students. The study found that the composition of a group by gender had little impact on the type or stability of verbal interaction. However, the frequency of verbal interactions was higher in mixed-gender groups than in other groups. Through this process, the gender-grouping in elementary school students' small group activities suggests a mixed-gender group.

• 대한기계학회논문집A
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• 제36권7호
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• pp.751-757
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• 2012

사용조건에서 수명시험을 수행할 경우 시험시간이 많이 소요되므로 사용조건보다 가혹한 스트레스 조건을 추가하여 가속수명시험을 수행하면 시험시간을 단축시킬 수 있다. 수명에 영향을 미치는 스트레스를 선정하여 각 스트레스의 사용조건과 가속조건에서 시험을 수행할 경우 가속 스트레스간에 교호작용이 존재할 수 있다. 그러나 기존의 연구에서는 2가지 이상의 가속 스트레스를 부과하여 가속수명시험을 수행할 경우 교호작용을 고려하지 않은 경우와 가속 수명에 대한 모델식을 제시한 연구들이 대부분이다. 본 논문에서는 기계류 부품의 수명에 영향을 미치는 가속 스트레스를 선정한 후 교호작용을 고려한 시험계획에 따라 가속수명시험을 수행한 자료를 이용하여 가속 계수와 가속 스트레스간의 관계식을 산출하는 방법을 제시하고자 한다. 또한 본 논문에서 제시한 교호작용을 고려한 가속시험방법과 가속 계수를 산출할 수 있는 모델식을 이용하여 복합적인 가속수명시험 수행시 쉽게 적용하고 결과를 산출할 수 있는 기초가 될 것으로 기대된다.

• 한국지반공학회논문집
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• 제17권6호
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• pp.5-14
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• 2001

본 연구에서는 사면안정 확보를 위해 설치된 억지말뚝과 보강사면의 안전율을 산정할 수 있는 간편설계 법을 제안하였다. 억지말뚝-지반간 상호작용은 하중전이법으로, 사면의 안전율은 Bishop의 간편법을 이용하여 산정하였다. 말뚝 간격에 따른 군말뚝 효과를 고려하기 위해 실내모형실험 및 유한요소해석을 수행하였으며 이 결과를 토대로 군말뚝 상호작용계수를 제안하였다. 제안된 군말뚝 상호작용계수는 말뚝중심간격이 좁아질수록 감소하였으며, 두부조건이 자유단인 경우가 다른 구속조건에 비해 큰 폭으로 감소하였다. 개발된 억지말뚝의 설계기법은 본 연구에서 수행한 원심모형실험, 현장시험 및 기존 유한요소해석결과와 비교.분석하였다. 본 해석프로그램은 3차원 유한요소해석에 비해 쉽고 간단하면서도 말뚝-지반간 상호작용에 의해 매우 복잡한 거동을 나타내는 억지말뚝을 비교적 적절히 설계 할 수 있음을 알 수 있었다.

• 한국농촌생활과학회지
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• 제6권2호
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• pp.121-136
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• 1995

The purposes of this research are to find out the standards which mothers consider seriously when choosing a day care center and mother's perception for the quality criteria of day care center, and to estimate the differences of these according to region. The sample consisted of 568 mothers with children using day care center located at the city of Taegu and Dalsung Gun. Collected data were analyzed by frequency, Percentage, chi-square, t-test, chronbach's $\alpha$. The results are summerized as follows : 1. In mother's perception for the quality criteria of day care center, the mothers living in the large city perceived more importantly in staff qualifications, administration - evaluation, staff- parent/staff- child interaction, curriculum, staffing, physical environment nutrition, health and safty than mothers in rural community. 2. In the importance classified by domains of the quality criteria of day care center, there were statistically significant differences according to the variable of region in staff qualifications, staff-parent/staff-child interaction, curriculum, staffing, physical environment 3. Given the present situations (income, transportation, location of workplace, etc.), when mothers choose a day care center, generally, staff-parent/staff-child interaction was the most important factor. And according to region, the distance to workplace or home was the most important factor in the case of mothers living in the large city, on the other hand, staff-parent/staff-chad interaction was the most important factor in the case of mothers living in rural community when mothers choose an ideal day care center, generally staff-parent/staff-chad interaction was the most important selection standard, and there were not remarkable differences according to region.

• 정보처리학회논문지D
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• 제10D권7호
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• pp.1207-1212
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• 2003

전자상거래의 발전과 함께 물류유통을 위한 분배망의 구성은 점차 복잡해지고 있으며, 이에 따라 분배계획이 점차 중요해지고 있다. 분배계획에 있어서 분배망의 관리는 중요하다. 분배망은 분배센터(DC)와 그 상호작용으로 나타낼 수 있다. DC 내부요인 및 DC의 상호작용으로 인한 외부요인은 분배망에 많은 영향을 미친다. 따라서 효율적인 분배망 관리계획의 수립을 위해서는 DC와 DC의 상호작용을 고려한 분배망의 분석이 필요하다. 지금까지 자원할당 같은 공급망 관리 관점의 연구가 이루어졌지만 공급망을 구성하는 분배망의 분석에 대한 연구가 이루어지지 않았다. 본 논문은 DC와 DC의 상호작용을 고려한 분배망 분석 기법을 제안한다. 제안 기법은 크게 두 가지 단계로 이루어진다. 먼저, 분배망은 DC와 DC의 상호작용을 포함한 그래프 형태로 모델링된다. 두 번째, 그래프로 모델링된 분배망은 도달성 트리를 이용하여 분석된다. 또한 예제모델을 제시하고, 이것의 분석을 통해 제안기법의 효용성을 보였다.

• BMB Reports
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• 제33권6호
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• pp.519-524
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• 2000

NF1 proteins are a family of DNA binding proteins which consist of two separate domains, N-terminal DNA binding domain and C-terminal transcription activation domain. The N-terminal 220 amino acids are highly conserved and are also known to mediate dimerization of NF1 proteins. The C-terminal regions of different type of NF1 proteins are heterogeneous and responsible for transcriptional activation. In this study, we tested the interaction between different domains of rat NF1-A protein by yeast two hybrid analysis and observed the interaction between C-terminal regions of NF1-A which do not contain the N-terminal dimerization domain. Our results showed that the C-terminal region of rat NF1-A between residues 231 and 509 strongly interacted not only with itself, but also with human NF1/CTF1 which is a different type of NF1. When the C-terminal region was divided into two fragments, one from residue 231 to 447 and the other from 448 to 509, the two fragments were able to interact with the C-terminal region of NF1-A significantly. This indicates that both fragments contain independent interaction domains. Analysis of the interactions with alanine substituted fragments showed that substitutions of the heptasequence, SPTSPTY of NF1-A, affected interaction between NF1 proteins. Our results strongly suggest that C-terminal regions may also be important for the formation of homo- and heterodimers in addition to the N-terminal dimerization domain. Also, the heptasequence motif may play some roles in dimer formation.

• 한국지반공학회지:지반
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• 제9권1호
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• pp.7-20
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• 1993

1988년 건설부에서 제정한 건축물에 대한 재진설계규준'에는 저면 전단력 산정시 지반계수가 1.0, 1.2, 1.5로 구분되어 있는데, 특히 얕은지반의 연약층에서 지반계수의 선정이 모호할 때가 많다. 또한 우리나라의 지반특성은 대부분 퐁화암 및 연암층이 20m이내에서 발견됨을 고려하여, 일차원 파전파 이론과 반무한 탄성이론 및 문헌을 통한 분석을 통해 지진 하중시 지반의 조건이 저면 전단력에 미치는 증폭효과를 비교분석하여 내진 설계시 적절한 지반계수 선택을 할 수 있도록 하였다.

• 대한인간공학회지
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• 제23권3호
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• pp.53-72
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• 2004

Today we are observing a lot of injuries, casualties, and property losses that are mainly caused by the defects of products. In order to derive safety designs, which minimize the possibility of such product liability-related accidents, we need to take into account the user-product interaction as an important part of the danger factor analysis. Existing risk analysis techniques, however, have some limitations in detecting comprehensive danger factors that are peculiarly involved in human errors and the functional defects of products. Researches on danger factor analysis regarding the user-product interaction have been carried out actively in ergonomics. In this paper, we suggest a novel product risk analysis technique, which is more objective and systematic compared to the previous ones, by combining a modified TAFEI (Task Analysis For Error Identification) technique with SASA (Systematic Approach to Accident Scenario Analysis) technique. By applying this technique to the product design practice in industry, corporations will be able to improve the product safety, consequently strengthening the competitiveness.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 가을 학술발표회 논문집
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• pp.269-276
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• 2000

Granular compaction piled raft systems have been effectively used in soft ground foundation to improve not only settlement but also bearing capacity. In the present study, to examine the behavior characteristics and bulging failure zone on granular compaction piled raft system, carbon rod tests have been performed. The test results are compared with the zone of bulging failure and the effects of pile-pile interaction obtained from the analytical approaches. In addition, parametric studies are peformed with considering pile slenderness ratio, Poisson's ratio and load sharing ratio.