• Proceedings of the Korean Society for Rock Mechanics Conference
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• 2001.03a
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• pp.177-187
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• 2001

암반사면의 안정성은 암반 내에 발달한 불연속면의 방향성과 파괴특성에 지대한 영향을 받는다. 두 조의 연속성이 좋은 절리가 발달한 암반의 거동을 해석하기 위해 FLAC의 FISH 언어로 작성된 편재 절리모델을 사용하여 절리암반사면의 안정성을 평가하였다. 해석 결과는 절리의 간격과 방향성을 달리하면서 수행된 UDEC 해석과 저면 마찰 모델 시험결과와 비교하였다. UDEC 해석과 저면 마찰 모형시험 의해 발생된 파괴면의 형상은 유사하였으며, 이 결과로부터 편재절리모델에 의한 FLAC 해석에서의 파괴면은 두 조의 교차하는 절리를 따라 계단식으로 파괴면이 발생함을 추정할 수 있었다.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 1996.10a
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• pp.162-166
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• 1996

재래식 간척 및 매립은 연안 간사지를 소멸시켜 수생생물의 산란 및 서식지를 훼손시킴으로써 해양 생태계를 파괴시킬 뿐 아니라 연안역 해수의 자정능력을 감소시켜 수질의 악화를 초래하고 있다(Y, Hosokawa, 1992). 따라서 향후 간척, 매립을 하거나 호안을 축조할 때에는 외해측에 수심이 얕고 경사가 완만한 해저 환경을 새롭게 조성함으로써 수질 및 해양 생태계를 보전하는 환경 친화적 연안개발 공법의 도입이 요망된다. (중략)

• Journal of Korea Water Resources Association
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• v.34 no.6
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• pp.651-657
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• 2001

The second-order long waves generated by short wave groups propagating over a step are theoretically investigated. The diffraction of short waves is firstly formulated and the governing equations of second-order long waves are then derived by using a multiple-scale perturbation method. It is observed that free and locked long waves are generated and propagated with different velocities.

• Journal of the Korean Geographical Society
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• v.37 no.2
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• pp.143-160
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• 2002

Since the 1990s, arable lands in mountainous areas of South Korea have widely been abandoned due to the serious depopulation for the last few decades. Abandonment of arable lands causes not only a decline in production functions of mountainous villages, but also landscape desolation and environmental problems. Due to same cause, Japan has also experienced the serious abandonment of arable lands in mountainous areas since the 1960s. For the last decade, Japanese government has poured investment to the conservation of terraced paddy fields in hilly and mountainous areas in order to restore those environment values. The attempts of Okayama prefecture for the conservation of terraced paddy fields are well known as a successful story in Japan. In order to suggest an effective conservation means far arable lands in mountainous areas in the context of Korea, this paper examines the background and the implementation means of Japanese conservation policy of terraced paddy fields in hilly and mountainous area, focusing on the case of Okayama prefecture.

• Journal of Korean Society of Steel Construction
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• v.27 no.2
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• pp.181-193
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• 2015

High-frequency staircases are widely used nowadays to meet aesthetics and functionality needed in modern architecture. Unfortunately, no design guide is available in domestic practice to predict response or evaluate the vibration performance of high-frequency staircases. SCI-P354 published by the Steel Construction Institute of UK provides the formula for effective impulsive force. However, this formula was shown to overestimate the response of high-frequency staircases excited by fast ascending and descending over 2.2Hz pace frequency because it was developed based on the walking test in a slow pace frequency. This study proposes a semi-analytical formula to predict the response of stiff staircases based on analytical and experimental studies of response acceleration for various walking frequencies covering 1.4~4.5Hz.

• Korean Chemical Engineering Research
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• v.59 no.1
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• pp.11-15
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• 2021

In this study, we tried to develop a method of accelerated degradation of the electrode by simply using a electronic loader without using a potentiostat to evaluate the durability of the electrode catalyst. To this end, the durability of the electrode was evaluated by repeating the stepwise voltage change using the self-generated voltage by introducing oxygen without introducing nitrogen into the cathode. For accurate electrode durability evaluation, that is, in order not to deteriorate the polymer membrane, the high voltage was lowered to 0.9 V in stepwise voltage change and the relative humidity was 100% to suppress degradation of the polymer membrane due to radicals. After 30,000 cycles (50 hours) of voltage change, the electrode active area decreased by 41.4%. It was confirmed that the electrode was deteriorated, but the polymer membrane was not deteriorated, that there was no increase in hydrogen permeability, no decrease in membrane thickness, and no increase in HFR(High Frequency Resistance).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.1
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• pp.63-69
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• 2006

New design equations for calculating the lateral-torsional buckling moment resistances of singly stepped I-section beams subjected to general loading on the top flange are suggested based on the investigations of elastic finite-element analyses. The new equations presented in this study are compared with current moment gradient modifiers presented by other researchers and specifications. The study considered almost loading cases on buildings and bridges. The proposed equations should be easily used to calculate the lateral-torsional buckling moment resistance of stepped I-beams.

• 한국HCI학회:학술대회논문집
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• 2006.02b
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• pp.789-794
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• 2006

UI (User Interface)는 끊임없이 진화한다. 사용자의 새로운 요구 사항을 만족시키기 위해, 기존 UI에 대한 불편 사항을 해결하기 위해, 경쟁 제품의 더 좋은 UI를 따라 잡기 위해, 그리고 새로운 기술로 기존에는 불가능했던 것이 가능해 짐으로 인해, UI는 지속적으로 더 좋은 방향으로 변화하고 있다. 특히 휴대폰과 같이 라이프사이클이 짧은 제품의 UI는 매 제품마다 UI를 변화시킬 수 없기 때문에 기업 입장에서의 전략적인 접근이 중요해 진다. 더욱이 충분한 검증 없이 이루어진 진화의 방향은 사용자가 원하는 방향과 일치하지 않게 되어 오히려 퇴화하는 문제도 발생할 수 있다. 본 논문은 UI가 생성, 유지, 융합, 소멸되어 가는 진화론적 발전 속성 및 그러한 속성에 영향을 주는 요소들을 살펴보고, 라이프사이클이 짧은 제품의 UI를 개선할 때 어떤 전략을 취하는 것이 기업 차원에서 좋은지를 설명한다. UI 진화 전략은 크게 점진적 개선을 추구하는 구릉식 전략과 한번에 도약하는 계단식 전략으로 나눌 수 있다. 위 두 전략들은 사용자 만족도, 개선에 필요한 비용과 그 가치, 개선 후의 리스크 (Risk)에 따라 장단점을 가진다. 결론적으로 본 논문에서는 두 전략 모두 서로 상반되는 장단점을 가지므로, 어느 한 전략을 취하기 보다는 UI 요소의 특성 및 변화의 규모에 따라 두 전략을 혼용하는 전략이 기업 입장에서 최적의 전략임을 주장한다.

• Proceedings of the Korean Geotechical Society Conference
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• 2002.10a
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• pp.689-696
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• 2002

The behavior of two-level soil-reinforced segmental retaining wall was examined using the finite element analysis. A number of different case was analyzed by varying the reinforcement length and the offset distance between the upper and lower wall. The results indicate that the interaction between the upper and lower walls can be neglected the upper wall is located beyond the distance of the lower wall height. A so found is that for moderate offset distances, the interaction between the two walls generally is limited to the external stability of the wall. Implication of the findings are discussed

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.176-183
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• 2008

This paper highlights the importance of carrying out global slope stability analysis as part of design calculations for geosynethetic walls in tiered configuration. Four design case histories were selected to examine the appropriateness of their design by performing additional slope stability analyses using the shear strength reduction method with in the frame work of finite element analysis. The results indicated that all of the walls examined, which were designed to meet the current design guide lines, did not satisfy the global slope stability requirement, and that longer reinforcements are required in the upper tiers to achieve the minimum factor of safety. Practical implications of the findings are discussed.