• The Journal of Engineering Geology
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• v.20 no.2
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• pp.155-167
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• 2010

In analysis of slope stability, deterministic analysis which yields a factor of safety has been used until recently. However, probability of failure is considered as a more efficient method because it deals with the uncertainty and variability of rock mass. In both methods, a factor of safety or a probability of failure is calculated for a slope although characteristics of rock mass, such as characteristics of joints, weathering degree of rock and so on, are not uniform throughout the slope. In this paper, we divided a model slope into several zones depending on conditions of rock mass and joints, and probabilities of failure in each zone are calculated and compared with that calculated in whole slope. The persistence of joint was also used as a parameter in calculation of probability of failure. A rock slope located in Hongcheon, Gangwondo was selected and the probability of failure using zoning and persistence as parameter was calculated to confirm the applicability of model analysis.

• Proceedings of the KSEG Conference
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• 2002.04a
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• pp.285-290
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• 2002

조사지역은 전라남도 함평군 함평읍으로부터 남쪽으로 엄다면 화양리, 학야리, 성천리 일대에 발달한 충적층으로서. 이 지역에는 남서-북동방향으로 광주단층이 통과하고 있는 것으로 추정된다. 충적층 하부에 발달한 단층을 포함한 대규모 파쇄대 파악에는 지표지질조사로서 한계가 있다. 따라서 이 연구에서는 물리탐사방법을 적용하여 충적층 하부의 대규모 파쇄대의 방향과 연장성을 파악하고자 하였으며, 사용된 물리탐사법은 전기비저항 2차원탐사, 전자탐사 그리고 자력탐사이다. 전기비저항 탐사결과 충적층 내에서 남북방향의 연장성을 갖는 전기비저항 이상대가 파악되었으나, 자력탐사와 전자탐사의 측정자료에는 이 이상대에대한 반응을 관찰할 수 없었다. 이는 전자탐사의 경우, 가탐심도가 매우 작은 EM31을 사용하였고, 또한 자력탐사는 주변 지질매체 간의 대자율 차이가 없는 것에 기인한 것으로 판단된다. 따라서 향후 지하심부의 탐사를 위해 전자탐사법중 TEM 탐사를 실시할 계획이며, 또한 낮은 전기비저항 이상대의 연장성을 정확히 파악하기 위하여 기 측정된 전기비저항 탐사 측선 사이를 탐사할 예정이다.

• Bulletin of the Society of Naval Architects of Korea
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• v.31 no.3
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• pp.72-76
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• 1994

LNG선의 신뢰성이 향상되고 안전운항이 오래 지속되고 있다. 이것은 모든 관련자들의 노력 덕택 이며 매우 고무적인 일이다. 현재보다도 미래에 LNG선의 역할은 보다 더 중요하게 될 것이다. LNG선의 신뢰성 유지는 한층 더 요구되어 질 것이다. LNG선과 같은 고기술선에서는, 실증성에 의거한 증명된 신뢰성이 필수적인 것이다. 이 점에서 미실증 분야로 있는 LNG선 수명 연장에는, 극히 신중한 대처가 필수 불가결하다. 기술면의 증명이 부족한 대로 수명 연장을 통해 사고를 일으킨다면, 열심히 쌓아올린 LNG선의 안전에 대한 전통이 붕괴될 염려가 있다. 여러 가지 요 인으로 볼 때 수명연장 요인은 존재하나, 대형사고 유발에 대한 Risk가 워낙 큼으로써 신중을 기해야 할 것이라고 생각한다.

• Journal of Adhesion and Interface
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• v.3 no.2
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• pp.9-16
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• 2002

In the synthesis of water-based polyurethane using self-emulsification process, after being neutralized, polyurethane pre-polymers containing ionic pendant groups are dispersed by simple convective mixing. Preparation of dispersion is followed by chain extension reaction, which is considered as important step for growth of the molecular weight of polyurethane. In this work, pH variations in the aqueous phase were monitored during the chain extension process in the presence of water-soluble diamines. The optimum degree of chain extension and the average particle size in the polyurethane dispersions were examined with varying ionic pendent group contents, type of chain extenders, and feed rate of chain extenders, The initial pH value in the aqueous phase linearly increased and the optimum chain extension point could be obtained from the intersection of two linear lines having different slopes, All average particle sizes before chain extension reaction were almost same, however, the final average particle size increased as feed rates of chain extenders increased, In addition, as the ionic pendant group contents increased, the particle size decreased since the hydrophilicity and hydrodynamic volume increased. As carbon numbers of the chain extenders increased, the final particle size increased significantly. From the results, it was concluded that the chain extension reaction took place among the particles not only in a particle.

• Economic and Environmental Geology
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• v.46 no.4
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• pp.313-327
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• 2013

In the study, three-dimensional geostatistical simulations on McMurray Formation which is the largest oil sand reservoir in Athabasca area, Canada were performed, and the optimal site for steam assisted gravity drainage (SAGD) was selected based on the predictions. In the selection, the factors related to the vertical extendibility of steam chamber were considered as the criteria for an optimal site. For the predictions, 110 borehole data acquired from the study area were analyzed in the Markovian transition probability (TP) framework and three-dimensional distributions of the composing media were predicted stochastically through an existing TP based geostatistical model. The potential of a specific medium at a position within the prediction domain was estimated from the ensemble probability based on the multiple realizations. From the ensemble map, the cumulative thickness of the permeable media (i.e. Breccia and Sand) was analyzed and the locations with the highest potential for SAGD applications were delineated. As a supportive criterion for an optimal SAGD site, mean vertical extension of a unit permeable media was also delineated through transition rate based computations. The mean vertical extension of a permeable media show rough agreement with the cumulative thickness in their general distribution. However, the distributions show distinctive disagreement at a few locations where the cumulative thickness was higher due to highly alternating juxtaposition of the permeable and the less permeable media. This observation implies that the cumulative thickness alone may not be a sufficient criterion for an optimal SAGD site and the mean vertical extension of the permeable media needs to be jointly considered for the sound selections.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.22 no.3
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• pp.119-125
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• 2016

Fresh-cut agricultural products provide convenience to consumers. However, quality changes or microbial growth can easily occur due to physical changes such as cutting and peeling etc. during processing. Therefore, efforts have been made to develop a functional packaging for extension of shelf life of fresh-cut agricultural products, food etc., and researches on prolongation of storage period have been actively developed. The shelf life is extended by antimicrobial, far infrared rays, air permeability, anti-fogging, weak current, ethylene gas adsorption or decomposition, gas composition changes such as MA (Modified Atmosphere) or CA (Controlled Atmosphere). The method of extending the shelf life by various complex factors. This paper based on the published literature to extend the shelf life of fresh-cut agricultural products, food etc., The paper has summarized the storage period extension packing method, packaging material for shelf life extension and comprehensive evaluation method.

• Environmental and Resource Economics Review
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• v.26 no.2
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• pp.173-203
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• 2017

The existence of rebound effect from road extension in Korea has been quantitatively verified using cross-sectional, time series data on four major cities - Seoul, Busan, Daegue and Incheon - between 2000 and 2013. The linear mixed effects model was constructed from six variables: total vehicle miles traveled (VMT), road extension, public transport users, gross regional domestic product (GRDP), regional population and fuel consumption. The main results can be summarized as VMT is positively correlated to road extension while negatively with public transport users. It indicates that the road extension-centered "supply-side" transportation policy induces "additional travel" and create "generated traffic" by enhancing driving efficiencies directly, or degrading other transport modes indirectly. Hence, the ultimate goal of road congestion reduction requires public transport-centered "demand management" rather than current supply-side policies.

• KOREAN POULTRY JOURNAL
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• v.15 s.165
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• pp.118-124
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• 1983

닭고기의 저장성을 연장시키기 위해서는 철저한 작업공정하에서의 탕침, 탈모를 거친 후 신속히 냉각하여 온도를 최대한 낮추어야 한다. 이렇게 한 후에야 저장 기간 연장 방법을 실시할 수 있는 것이다.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05d
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• pp.163-169
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• 1996

원전의 수명을 결정하기 위해서는 발전소 안전성과 성능을 보증하는 기술적 측면뿐만 아니라 경제적인 측면도 고려하여야 한다. 본 논문에선 원전수명관리 경제성 평가를 수행하는 WECON 프로그램을 소개하고, 이 프로그램을 이용하여 입력 변수의 민감도를 분석하였으며, 이 결과 나타난 상위 6개의 입력변수에 대해 사례 연구를 실시하였다. 이 6가지 변수에 대한 사례연구에서 원전 수명관리의 경제적 이득은 여러가지 경우에 따라 변화 하는 것으로 나타났으며, 기기비용이 연장운전 년수에 비례하여 증가한다고 가정한 경우 무한정 연장운전이 경제적이 아니라 Optimum 연장운전 point가 있는 것으로 나타났다.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.05a
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• pp.175-177
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• 2004

무전극 형광램프의 출력선 연장은 무전극 램프가 가지는 장수명 등의 이점을 최대화할 수 있는 방안이 된다. 하지만 이를 위해서는 연장에 따라 발생하는 요인들 -공진주파수의 변경, 온도변화에 따른 안정성 등을 고려하여 인버터의 설계가 이루어져야 한다. 이를 위해 본 연구에서는 ENDURA 150W 인버터의 출력선을 25m 연장하기 위해서 출력선을 고려한 공진 주파수를 설정하였고 온도변화에 따른 대책들을 제시하였다.