• Journal of Labour Economics
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• v.39 no.2
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• pp.35-51
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• 2016

Using the Korea Labor and Income Panel Study (KLIPS) from 2000 to 2008, we estimate the Frisch elasticity of labor supply. Our point estimates of the intensive margin elasticity are around 0.23. The estimates are not sensitive to changes in household income and assets as well as changes in workweek regulation during the sample period that workers shall work for 5 days per week from Monday to Friday. We also estimate the extensive margin elasticity by considering labor market participation. We find that the point estimates at the extensive margin are greater than those at the intensive margin, but not statistically significant.

• Korean Journal of Child Studies
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• v.22 no.3
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• pp.31-48
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• 2001

This study was designed to examine various patterns of developmental change in children's recall, strategic behaviors, and meta-memory with a sort-recall task in relation to utilization deficiencies. Memory tasks consisting of 18 pictures were presented individually to 48 seven-year-old children in each of 7 sessions. Sessions 1 and 2 were baseline; Sessions 3 and 4 were for strategy training, including the organization group, the self-regulation group, the organization/self-regulation group and control group. Sessions 5, 6, and 7 were unprompted tests of strategy maintenance. Results showed significant differences between the 4 groups in their recall, strategy repertories and strategy evaluation. Findings were discussed in terms of the analysis of memory strategy and memory development.

• Journal of the Korean Wood Science and Technology
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• v.16 no.3
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• pp.38-47
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• 1988

표고버섯(Lentinus edodes) 균에 의한 졸참나무(Quercus serrata)골목의 미시형태적 변화를 주사형전자현미경 (SEM)을 통해 관찰하였다. 표고 재배 5년후 골목의 중량 감소율은 50%에 달했다. 구성세포중 목섬유는 표고균사에 의해 쉽게 분해되었으나 도관과 유세포는 저항성을 나타냈다. SEM 관찰 결과 표고균사는 세포내강(內腔)에서부터 세포벽을 서서히 분해 박벽화(薄壁化)시켰으며, 또한 Cell corner가 중간층보다 먼저 공격을 받아 분해 되었으나 중간층은 쉽게 분해되지 않았다. 흥미롭게도 연부후(軟腐朽)의 전형적 형태인 2차막에서의 공동(空洞)역시 백색부후균인 표고균사에 의해 형성 되었다. 이상의 관찰결과 표고균은 백색부후와 연부후균이 갖는 미시형태적 특징을 동시에 보여 주었다. 아울러 중간층 보다 Cell corner가 먼저 선택적으로 분해되며, 도관세포벽의 분해저항성을 세포벽 구성 리그닌의 화학적 특성과 연관시켜 논의했다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.3
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• pp.409-413
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• 2006

The accumulated deformation due to the undrained creep causes the general stability problem for the overall soil mass. In this study, the time-dependent constitutive equation, into which a damage law, modified cam clay model, and Perzyna's generalized viscous theory were incorporated, was derived microscopically. The model prediction agreed well with the experimental result including the case of the undrained creep rupture.

• Journal of Welding and Joining
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• v.14 no.2
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• pp.79-89
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• 1996

일정진폭하중과 과대하중비 2.5의 단일 인장과대하중에 의한 4140강 용접부 의 피로균열성장거동을 실온과 -45.deg.C의 저온에서 피로시험과 파면관찰을 통하여 고찰하였다. 이때, 용접부 미시조직의 영향을 평가하기 위해 모재(parent metal), 열영향부(as-welded HAZ), 열처리된 열영향부(PWHT HAZ)로 나누어 응력비 0과 0.5로 CT시험편을 이용하여 피로시험을 실시하였다. 피로균열성장거동은 재료의 미시조직과 온도변화보다는 응력비에 크게 영향을 받았으며, 단일 과대하중에 의한 피로균열성장 지연효과가 모든 재료에서 상당히 크게 나타났다. 전자현미경에 의한 피로파면 관찰 결과, 실온에서는 연성의 스트라이에이숀과 -45.deg.C에서는 의벽개파면과 같은 피로 균열성장거동을 나타내고 있다.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.1874-1878
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• 2008

본 연구에서는 물고기 서식처의 수리조건을 조사하기 위한 현장조사와 대상지에서의 미시서식처의 분포를 파악하기위한 수치계산을 실시하였다. 현장조사는 미호천과 금강이 합류되는 지점으로부터 약 24km 상류에 위치한 동경127도26분-북위36도41분 충북 청원군 오창면의 미호천 일부구간을 대상으로 수리학적 특성 조사, 지형측량 및 서식처별 대표어종 조사를 수행하였으며, 수치실험은 하천에서의 흐름거동을 2차원적으로 해석하는데 많이 사용되고 있는 상용프로그램인 SMS (Surface - Water Modeling System)의 RMA2 모형에 현장조사로부터 얻은 결과들을 입력함으로서 진행하였다. 그 결과 유속과 수심에 따른 서식처 구분이 가능하였으며, 현지특성을 재현한 수치모형 결과는 대상하천에서의 서식지 분포를 정량적으로 나타내었다.

• Korean Journal of Child Studies
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• v.22 no.1
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• pp.97-107
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• 2001

This study argues the nature of the microgenetic method in respect to child development research and explores its merits and limitations. The microgenetic method focuses on observations that span the entire period from the beginning of developmental change to the time it reaches a relatively stable state. This produces a high density of observations relative to the rate of change in the phenomenon. In this way, observed behavior may be used in intensive trial-by-trial analysis. The microgenetic method is superior to other methods in the possibilities for observing developmental changes as they occur, examining various aspects of change, detecting variability in behavior, and flexibility in application regardless of theoretical perspectives. Limitations of this method include reliability problems due to repeated observations, artificiality relative to the natural situation, inconsistency of short-and long-term change, and demands on children's motivation for participation in research.

• Geotechnical Engineering
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• v.3 no.2
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• pp.7-16
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• 1987

The dynamic properties of soils are affected by parameters like, gradation characteristics, void ratio, confining pressure, etc. . This study mainly investigated experimentally the effect of gradation on the dynamic properties of sands with the effect of void ratio and confining pressure. Test results showed that shear modulus/damping ratio was increased/decreased with the decrease of void ratio and with the increase of confining pressure. When the fine content increased, shear modulus/damping ratio was decreased/increased. This study explained this phenomenon by the concept of the "effective number of contacts" and the "dead space".ot;dead space".uot;.

• Spatial Information Research
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• v.6 no.1
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• pp.35-45
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• 1998

In order to support effective decision-makings related to greenery planning, this study construct a fundamental database about greenery information for Seoul metropolitan area using GIS and Remote Sensing. Greenery evaluation index consists of ecological/ environmental, utilization, social condition value which are used to determine the development priority of undevelopment parks. These indexes will also be utilized for the green area conservation classification for Seoul metropolitan area. This study is a part of previous project called "Management Policy of the Total Amout of Greenery", which was conducted in Seoul Development Institute.Institute.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.04a
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• pp.220-223
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• 2003

The methodology of micromechanical finite element method (MFEM) is proposed to calculate the micromechanical strains on fiber and matrix under mechanical and thermal loadings. For micromechanical analysis, composite structure is idealized the square and hexagonal unit cells. Boundary conditions are determined to calculate the effective material properties of composites and the strain magnification matrix. And they are verified by comparing with the results from multi cells, and the strain distributions of the unit cells are in accordance with those of the multi cells. Finally, the effective material properties of composite structure are obtained with respect to its fiber volume fraction and compared with results from rules-of-mixture.