• Journal of Korean Society of Coastal and Ocean Engineers
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• v.28 no.1
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• pp.7-12
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• 2016

In this study, a simplified collision model of pile protective structures against a navigation vessel was proposed and verified. The model of pile protective structure were composed by two plastic hinges at below of cap slab and the inside of ground. A nonlinear equation of motions was developed in consideration of the kinematic energy, potential energy and deformation energy in collision event. The developed simplified model were verified by the precise finite element collision analysis of the vessel and the protective structure.

• Journal of the Korean GEO-environmental Society
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• v.10 no.5
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• pp.69-73
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• 2009

In this study, three dimensional numerical analyses were performed with variation of pile spacing (S=3D, 4D, 5D) to compare the behaviour of single pile and pile group with cap in granite soil. In order to compare and analyze the lateral resistance of single pile and pile group by changing pile spacing, the pile group with array of $1{\times}3$ was employed. To reduce the computation time the symmetric boundary condition was used. And Druker-Prager model and elasticity model were used for granite soil and for concrete pile and cap, respectively. Using the analyses results of pile group in granite soil under lateral loading, p-y curve for pile group and single pile with changing pile spacing was drawn. With p-y curve p-multiplier was evaluated. As a result of analysis, the value of p-multiplier was increased with increasing pile spacing under 1.0 due to pile shadow effects.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2014.06a
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• pp.144-145
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• 2014

기존 디지털 방송은 제한된 데이터 전송율로 인하여 시청자가 요구하는 다양한 데이터 서비스, 고해상도를 가지는 비디오 서비스와 같은 리치 멀티미디어 서비스를 제공하는 것이 현실적으로 어렵다. 그러나, 최근 들어 유무선 인터넷의 속도가 향상되고 소셜 서비스 등 다양한 인터넷 서비스 모델이 등장함에 따라서 통신망을 활용한 하이브리드 멀티미디어 방송 서비스가 제시되어, 방송 서비스가 가지는 특성을 유지하면서 다양한 시청자의 요구를 만족시키는 것이 가능해 졌다. 본 논문에서는 하이브리드 방송 서비스의 일종인 동적 계획 기반 하이브리드 방송 서비스 모델과 이를 가능하게 하는 송신 시스템 구성을 제안한다. 제안된 시스템은 새롭게 추가된 스케줄링 서버를 포함하고 있으며, 이 스케줄링 서버에 의해서 방송 콘텐츠의 비디오 해상도, 제공 시간, 전송 경로 등을 결정하는 것을 특징으로 한다.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.343-346
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• 2010

형상기억합금이 삽입된 복합체는 힌지나 추가적 작동기 없이 그 자체로서 지능 구조의 역할을 할 수 있어 많은 분야에서 활발히 연구되고 있다. 본 논문에서는 형상기억합금(Shape Memory Alloy) 선이 삽입된 $\cap$자형 복합재를 제안하고, 형상기억합금과 모재가 정해진 경우의 곡률 변화에 영향을 주는 주요 설계 변수를 복합재의 너비, 두께, 형상기억합금의 편심률을 설계변수로 가정하고 유한요소 해석과 패널 제작 및 실험을 통해 검증한다. 먼저 라고다스(Lagoudas)모델을 형상기억합금의 구성방정식으로 이용한 유한요소해석모델을 구성하여 수치해석을 수행하고, 11 종류의 형상기억합금 선이 삽입된 유리섬유강화복합재(Glass Fiber Reinforced Plastic) 패널을 제작하여 열하중에 따른 곡률변화를 관찰한다. 해석결과와 실험결과의 비교를 통해 해석모델의 타당성을 검증하며, 해석을 통해 각 설계 변수들의 곡률변화에 대한 영향을 파악한다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.6
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• pp.3571-3586
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• 2014

This study examined the relationship among PsyCap(positive psychological capital), psychological empowerment, personal creativity and verified the mediated effects of intrinsic motivation in this relationship using the SEM(Structural Equation Model). For this study, the data was collected through on/off-line surveys of members and managers from 12 different enterprises. Among the 418 answers from voluntary participating employees, 332 answers were finally used for statistical analysis. The results were as follows. First, PsyCap had a positive influence on the intrinsic motivation and personal creativity. Second, Psychological Empowerment had a positive influence on intrinsic motivation, but psychological empowerment has no influence on creativity. Third, intrinsic motivation had a meaningful influence by partially mediating PsyCap and personal creativity but completely mediated psychological empowerment and personal creativity. This study focused on intrinsic motivation among the internal factors that have influences on showing personal creativity and has importance in the point that it has suggested the statistical significance by analyzing the psychological/emotional mechanism to reinforce this intrinsic motivation in a positive way. Positive analysis on the relationships among these variables suggests a theoretical meaning on providing a future direction for the study and practical meaning on providing ideas to reinforce the employees' personal creativity. The details of this study are followed in the main text.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.302-309
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• 2017

The influence of the pile diameter, center to center pile spacing, internal friction angle of embankment soil, and height of embankment on the arching efficacy of the embankment pile was investigated. The arching efficacy, which was derived by the arch model developed in the embankment soil was calculated using two methods, one that considers crown failure of the arch and the other that considers load on the pile cap and critical relative spacing ratio for which the arching efficacy calculated by the two methods are the same. According to the computed results in this study, the arching efficacy calculated from a consideration of the load on pile cap governs when the relative spacing ratio becomes smaller and that calculated from the theory of crown failure governs when the relative spacing ratio becomes larger. The critical relative spacing ratio below which the arching efficacy calculated from a consideration of the load on pile cap governs the design decreases with increasing value, which is defined by the ratio of the pile diameter to the pile center to center spacing. Critical relative spacing ratios, which correspond to the values of 0.5 and 0.2 were 0.35 and 0.85, respectively. Considering the computed results, the critical relative spacing ratio decreases with increasing Rankine passive earth pressure coefficient and critical relative spacing ratios, which correspond to values of 5 and 2, were 0.23 and 0.85, respectively. The arching efficacy, which corresponds to the area ratio of 9%, was 54% and the one that corresponds to the value of 3 was 61%; the critical relative spacing ratios, which correspond to those arching efficacies, were greater than 0.5.

• Journal of the Korea Concrete Institute
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• v.15 no.3
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• pp.433-442
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• 2003

This paper presents a hypoplastic model for three-dimensional analysis of concrete structures under monotonic, cyclic, proportional and non-proportional loading. The constitutive model is based on the concept of equivalent uniaxial strains that allows the assumed orthotropic model to be described via three equivalent uniaxial stress-strain curves. The characteristics of these curves are obtained from the ultimate strength surface in the principal stress space based on the Willam-Warnke curve. A cap model is added to consider loading along or near the hydrostatic axis. The equivalent uniaxial curve is based on the Popovics and Saenz models. The post-peak behavior is adjusted to account for the effects of confinement and to describe the change in response from brittle to ductile as the lateral confinement increases. Correlation studies with available experimental tests are presented to demonstrate the model performance. Tests with monotonic loading on specimens under constant lateral confinement are considered first, followed by biaxial and triaxial tests with cyclic loads. The triaxial test example considers non-proportional loading.

• Korean Journal of Construction Engineering and Management
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• v.16 no.2
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• pp.65-76
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• 2015

The Clean Development Mechanism (CDM) is the multi-lateral 'cap and trade' system endorsed by the Kyoto Protocol. CDM allows developed (Annex I) countries to buy CER credits from New and Renewable (NE) projects of non-Annex countries, to meet their carbon reduction requirements. This in effect subsidizes and promotes NE projects in developing countries, ultimately reducing global greenhouse gases (GHG). To be registered as a CDM project, the project must prove 'additionality,' which depends on numerous factors including the adopted technology, baseline methodology, emission reductions, and the project's internal rate of return. This makes it difficult to determine ex ante a project's acceptance as a CDM approved project, and entails sunk costs and even project cancellation to its project stakeholders. Focusing on hydro power projects and employing UNFCCC public data, this research developed a prediction model using logistic regression and CART to determine the likelihood of approval as a CDM project. The AUC for the logistic regression and CART model was 0.7674 and 0.7231 respectively, which proves the model's prediction accuracy. More importantly, results indicate that the emission reduction amount, MW per hour, investment/Emission as crucial variables, whereas the baseline methodology and technology types were insignificant. This demonstrates that at least for hydro power projects, the specific technology is not as important as the amount of emission reductions and relatively small scale projects and investment to carbon reduction ratios.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.1
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• pp.98-102
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• 1995

Popped popcorn generally have a regular popping direction and typical shape. But the reason and mechanism are not clear yet. This experiment was carried out to investigate the shape moulding factor of popped popcorn. Pericarp thickness of tip-cap section of kernels is slightly thicker than that of top section and this fact provides the important information to the reason. Popping starts when the moisture pressure of heated popcorn is increased and reaches at the critical pressure. Therefore, in the same moisture pressure conditions, top sections are bursted first because their pericarp section is thinner than that of tip-cap section. At the very moment tip-cap sections pull down the top sections of peri carp as bi-metal does. So kernels which removed tip-cap section showed the irregular popping shape because they lost the tip-cap pericarp function. How-ever, kernels which removed embryo showed the typical popping shape but their popping volume was small due to emition and shortage of critical moisture pressure. But kernels which removed the whole pericarp and top pericarp were not popped at all because moisture was entirely emitting out of kernels. These results suggest that the shape moulding factor of popped popcorn is the pericarp thickness differences between the top and tip-cap section of kernels.

• Korean Journal of Construction Engineering and Management
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• v.7 no.5
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• pp.94-104
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• 2006

The changed Korean government law associated with the public apartment housing supply, so called the $^{\circ}{\AE}$Apartment Sales Price $Cap^{\circ}{\phi}$, requires new system for estimating construction cost in order to set appropriate price. A model apartment project was carefully designed and its construction cost were analyzed in many different ways. Based on the analyses outcomes, 1,028,000 Won/m2 (excluding cost for underground parking lot) is the most appropriate Price Cap for a smaller than $85{\beta}{\geq}$ apartment unit. Further, it was revealed that the price have to be adjusted reflecting such factors as underground size; structural system; external complex quality; and consumer preferences. Findings from this study will enable the Korean government to realize faster and better application of the related laws. The methodology for obtaining appropriate apartment construction cost will also benefit for future researchers.