• Journal of the Korean Geotechnical Society
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• v.30 no.12
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• pp.5-14
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• 2014

Most of slope failures have taken place between June and September in Korea, which cause a considerable damage to society. Rainfall intensity and duration are very significant triggering factors for landslide. In this paper, landslide-triggering rainfall threshold consisting of rainfall intensity-duration (I-D) was proposed. For this study, total 255 landslides were collected in landslide inventory during 1999 to 2012 from NDMI (National Disaster Management Institute), various reports, newspapers and field survey. And most of the required rainfall data were collected from KMA (Korea Meteorological Administration). The collected landslides were classified into three categories: debris flow, shallow landslide and unconfirmed. A rainfall threshold was proposed based on landslide type using statistical method such as quantile-regression method. Its validation was carried out based on 2013 landslide database. The proposed rainfall threshold was also compared with previous rainfall thresholds. The proposed landslide-triggering rainfall thresholds could be used in landslide early warning system in Korea.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2002.04a
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• pp.28-28
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• 2002

가스터빈 엔진을 운용하는 데 있어서 가/감속율을 크게 하면 엔진성능 천이 시간은 짧으나 압축기에서의 서지나 터빈 입구온도의 급격한 상승이 발생할 수 있으며 가/감속율을 작게 하면 엔진은 안정적이나 천이시간이 길어지게 되어 결과적으로 엔진의 동적 응답성이 나빠지게 된다. 또한 압축기에서 발생할 수 있는 서지를 방지하기 위하여 압축기 서지 마진이 l0%∼20%인 서지 한계선(조정선)을 설정하여 엔진이 서지 한계선을 넘지 않도록 제어한다.

• The Journal of Engineering Geology
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• v.26 no.2
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• pp.197-205
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• 2016

Rainfall-induced landslide disaster case histories are typically required to establish critical lines based on the decrease coefficient for judging the likelihood of slope collapse or failure; however, reliably setting critical lines is difficult because the number of nationwide disaster case histories is insufficient and not well distributed across the region. In this study, we propose a method for setting the critical area to judge the risk of slope collapse without disaster case history information. Past 10 years rainfall data based on decrease coefficient are plotted as points, and a reference line is established by connecting the outermost points. When realtime working rainfall cross the reference line, warning system is operating and this system can be utilized nationwide through setting of reference line for each AWS (Automatic Weather Station). Warnings were effectively predicted at 10 of the sites, and warnings could have been issued 30 min prior to the landslide movement at eight of the sites. These results indicate a reliability of about 67%. To more fully utilize this model, it is necessary to establish nationwide rainfall databases and conduct further studies to develop regional critical areas for landslide disaster prevention.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2011.11a
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• pp.159-161
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• 2011

항만국통제제도는 기항지국별로 항만국통제를 시행하던 것이 지역별로 협력체제를 구축하여 기준미달선 제거를 위해 노력하게 되었다. 하지만 지역협력체제에 법적 구속력이 없어 한계성을 보이고 있으므로 조약화하는 것이 기준미달선을 제거하는 최선의 방법이 될 것이다. 지역협력체제 MOU는 실질적 구속력이 없어 한계성을 보이고 있으므로 강제화한다면 항만국통제 목적을 달성할 것이고 이것이 확대되면 범세계적으로 기준미달선은 제거되고 해상안전과 해양환경보호는 달성될 것이다.

• Journal of Fisheries and Marine Sciences Education
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• v.21 no.1
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• pp.52-58
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• 2009

With the increase of marine traffic capacity, marine accidents have also been increased for recent several years. Especially watch officer must maneuver not entering into the safety minimum approaching distances when two power-driven vessels are crossing. The author calculated the safety minimum approaching distances to provide a navigator with them based on zig-zag motion by experimental ship. The obtained results are summarized as follows : 1. The greatest distance is to be kept by the give way vessel to avoid collision when the crossing course angle is $90^{\circ}$. In this case the safety minimum approaching distance must be more than from 5 times to 11 times of her own length according to her size. 2. The watch officer of the give way vessel must always take an action to avoid collisions outside of the safety minimum approaching distance. 3. When the navigator used rudder to small angle than to large angle to avoid other vessel he must take action outside the sufficient safety minimum outside distances in advance. 4. Risk of collision in crossing situation is more greater in obtuse situation than in acute one.

• Proceedings of the Safety Management and Science Conference
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• 2013.04a
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• pp.321-327
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• 2013

실리콘 기반의 반도체 산업은 Moore Rule에 따른 집적도 향상에 힘입어 눈부시게 발전해 왔다. 그러나, 최근 최소 선 폭 수준이 10nm에 다다르면서 공정의 난이도는 한계에 다다랐으며, 한계를 극복하기 위해서는 폭발적인 비용 투입만으로도 확신할 수 없기 때문에 선 폭 미세화 (Scaling Down)를 통한 집적도 향상은 더 이상 비용/성능 측면에 효율적이지 못하다. 이러한 상황으로 인해 반도체 업체들은 한계를 극복하기 위한 여러 가지 방법을 강구하고 있는 실정이다. 이러한 (개발 난이도 증가, 소형화, 경량화, 고집적화에 대한 고객 요구 증대) 한계를 해결하기 위하여, 크게 3가지 관점에서 지속적으로 연구가 이루어 지고 있다. 여기서는 현재 가장 활발한 연구가 이루어지고 있으며, 가장 대응이 용이한 PKG 신기술 개발에 대하여 다루고자 한다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2022.07a
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• pp.209-211
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• 2022

국내 게임 시장 규모는 2021년 21조원을 넘으며 시장이 빠르게 성장하고 있다. 이러한 매출 규모에 큰 비중을 차지하는 상품은 확률형 가챠 아이템이 매출에 많은 부분을 담당하고 있다. 본 논문에서는 현재 게임 산업에서 사용되는 가챠 시스템에 대한 문제점을 소개하고 한계선이 없는 가챠 시스템에 대한 내용을 제시하면서, 최근 업계에서 한계선이 없는 가챠에 대한 대처법으로 출시하고 있는 천장 시스템에 대하여 소개와 천장 시스템의 성공 사례 및 앞으로 천장 시스템이 어떤 방향으로 개선 되야하는지에 대한 내용을 제시한다.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1999.04a
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• pp.41-41
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• 1999

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.5 no.2
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• pp.109-112
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• 2007

The possibility and limitation of one dimensional nano scale electron shielder is briefly discussed. A Nano scale electron shielder will reduce the weight and size of shielding materials. However, practical application still requires further research. In this work, we discuss general problems related to nano scale electron shielder, by taking an arbitrary one dimensional potential barrier as an example.

• Korean Journal of Optics and Photonics
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• v.22 no.6
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• pp.269-275
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• 2011

We propose a metal-dielectric hybrid waveguide structure consisting of a single metal nanowire placed on a flat dielectric slab. Mode size and propagation loss of the surface-plasmons confined in the metal-dielectric gap are compared with those of the complementary structure with a dielectric nanowire on a metal surface. In the case of the nanowire's diameter much smaller than the wavelength the two structures reveal quite different characteristics; the dielectric nanowire-on-metal has longer propagation distance, but only the metal nanowire-on-dielectric exhibits a mode size two fold smaller than the diffraction limit. The proposed hybrid structure may therefore be more suitable for realization of nanocavity lasers.