• Journal of Industrial Technology
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• v.30 no.B
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• pp.33-40
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• 2010

This paper is results of analyzing the characteristics of rainfall triggering landslides and geometry of slopes, caused by the heavy rainfall and antecedent precipitation by Typhoons Ewiniar and Bilis at Chuncheon area in Gangwondo around July in 2006. As results of analyzing the characteristics of rainfall, landslides in 131 sites were found to happen due to the heavy rainfall having the maximum intensity of rainfall in an hour during July 15 and antecedent precipitation during July 12 to 14 causing the ground to be weak by increasing the degree of saturation previously. From results of analyzing the geometrical characteristics of 131 slopes where landslides occurred, the slope width were in the range of 6~10m. The average slope length and angle were 46m and $51.8^{\circ}$, which was relatively steep slope, respectively. Landlises occurred in the elevation of 400 - 500 m with the most probable frequency.

• Journal of the Korean Society of Safety
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• v.26 no.2
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• pp.83-88
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• 2011

Annually, many parts of the Korea have been damaged from the localized heavy rain and/or typhoons which peak between June and September, which result in extensive financial and human loss. Especially, because the most area of Gangwon province is composed of the steep slope mountains, the damages by the debris flow or land-sliding are more frequent and the frequency has been increased. To analyze the characteristics and causes of these debris flow disasters, lots of study are recently being conducted through database of weather, hydrologic, soil etc using a GIS or remote sensing. In this study, we applied GIS method to analyze the risk of the debris flow area. With the statistical analysis and infinite slope stability model(SINMAP), the debris flow risk level of the mountain slope was generated. As a result, the GIS statistical analysis showed high correlation that former model of SINMAP in determining the debris flow risk area.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.5
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• pp.326-333
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• 2009

Design life-time of a wind turbine is required to be at least 20 years. In the meantime, the wind turbine will experience a lot of load cases such as extreme loads and fatigue loads which will include several typhoons per year and extreme gusts with 50 years recurrence period as well as endless turbulence flow. Therefore, IEC61400-1 specifies design load cases to be considered in the wind turbine design and requires the wind turbine to withstand the load cases in various operational situations. This paper investigates the ultimate loads which the wind turbine will experience for 20 years and their characteristics based on the IEC61400-1 using an aero-elastic software, GH-Bladed. And the performance characteristics of a wind turbine such as electrical power generation and annual energy yield are also investigated.

• Journal of the Korean Society of Visualization
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• v.5 no.2
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• pp.9-13
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• 2007

Typhoon simulation based on dynamical forecasting results is demonstrated by utilizing geodesic model GME (operational global numerical weather prediction model of German Weather Service). It is based on uniform icosahedral-hexagonal grid. The GME gridpoint approach avoids the disadvantages of spectral technique as well as the pole problem in latitude-longitude grids and provides a data structure extremely well suited to high efficiency on distributed memory parallel computers. In this study we made an attempt to simulate typhoon 'NARI' that passed over the Korean Peninsula in 2007. GME has attributes of numerical weather prediction model and its high resolution can provide details on fine scale. High resolution of GME can play key role in the study of severe weather phenomenon such as typhoons. Simulation of future typhoon that is assumed to occur under the global warming situation shows that the life time of that typhoon will last for a longer time and the intensity will be extremely stronger.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.1076-1085
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• 2009

Recent heavy rains and typhoons broke down road slopes, which caused a hazard to safety. As a result, interests in the effective investment for disaster prevention is increasing. Measures of investigation method for slope have been taken, but the financial costs have never been analysed. This study applied the cost-benefit analysis theory used in public economics to the evaluation of the financial reasonability of management for slope. By applying cost-benefit analysis to road slope investigation method, the reduction of safety costs and resulting financial benefits can be seen and it also clarifies the reasonability and investment effects of slope management.

• Wind and Structures
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• v.3 no.2
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• pp.133-142
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• 2000

Engineered structures such as buildings and bridges in certain regions of the world need to be designed to withstand tropical cyclone winds, otherwise known as typhoons or hurricanes. In order to carry out this design, it is necessary to be able to estimate the maximum wind speeds likely to be encountered by the structure over its expected lifetime, say 100 years. Estimation of the maximum wind involves not only the overall strength of the tropical cyclone, but the variation of wind speed with radius from the centre, circumferential position, and with height above the ground surface. In addition, not only the mean wind speed, but also the gust factor must usually be estimated as well. This paper investigates a number of recent mathematical models of tropical cyclone structure and comments on their suitability for these purposes in a variety of scenarios.

• Wind and Structures
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• v.7 no.5
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• pp.345-357
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• 2004

In the 1990s, four strong typhoons hit the Kyushu area of Japan and inflicted severe damage on power transmission facilities, houses, and so on. Maximum gust speeds exceeding 60 m/s were recorded in central Kyushu. Although the wind speeds were very high, the gust factors were over 2.0. No meteorological stations are located in mountainous areas, creating a deficiency of meteorological station data in the area where the towers were damaged. Since 1995 the authors have operated a network for wind measurement, NeWMeK, that measures wind speed and direction, covering these mountainous areas, segmenting the Kyushu area into high density arrays. Maximum gusts exceeding 70 m/s were measured at several NeWMeK sites when Typhoon Bart (1999) approached. The gust factors varied widely in southerly winds. The mean wind speeds increased due to effects of the local terrain, thus further increasing gust speeds.

• Proceedings of the Korea Water Resources Association Conference
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• 2002.05a
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• pp.59-64
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• 2002

An expert system, to assist dam managers for five dams along the Saikawa River, has been developed with a primary objective of achieving swift and accurate reservoir operation decision-makings during floods. The expert system is capable of supporting on decision-makings upon establishment of flood management procedure and release/storage planning. Furthermore, an attempt was made to improve reservoir inflow prediction models for better supporting capability. As a result, accuracy on prediction of inflow up to 7 hours ahead was improved, which is important for flood management of the five dams, using neural network. The neural network inflow prediction models were developed for each types of floods caused by frontal rainfalls, snowmelt and typhoons, after extracting relevant meteorological factors for each.

• Journal of Ocean Engineering and Technology
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• v.24 no.3
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• pp.31-37
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• 2010

During typhoon periods, coastal regions are often directly flooded by typhoon-surges. There are also many cases where coastal regions are inundated by river inundations or dam breaks. However, most studies on coastal flooding by typhoons have been restricted to cases involving the sea. Flooding by river inundation has been excluded in those studies. Usually ocean numerical models are not applied to river flow because the governing equations for ocean flow and river flow are not the same. For a coastal flooding simulation with river inundation, POM, the three-dimensional numerical ocean model, was applied to the popular river flow problems, dam-break problem, and flows over a spillway. The simulated results showed good agreement with other numerical simulations and measured data, suggesting the possibility of using POM in coastal flooding simulations involving direct coastal surges and river inundations.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2014.10a
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• pp.94-95
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• 2014

10년간(1992-2011년)의 데이터를 이용하여 태풍의 피크기에 대하여 분석하였다. 얻어진 주요 결과를 정리하면 다음과 같다. 최대풍속 20-29m/s와 40-49m/s의 태풍이 상대적으로 높은 비율을 차지하고 초강력 태풍이라고 구분할 수 있는 최대풍속 50-59m/s의 태풍도 많은 수를 차지한다. 최대풍속 50m/s 이상의 초강력 태풍은 전체 태풍 수의 24％를 차지하고 최대풍속 60m/s 이상의 태풍도 존재하여 이에 대한 항해자의 경계를 요한다. 태풍의 피크기가 주로 나타나는 곳은 북위 15도에서 25도, 동경 120도에서 140도의 해역이다. 태풍 피크기의 유지시간은 12시간 이내가 전체 태풍의 27％(59개), 13-24시간이 29％(64개), 25-48시간이 30％(66개)를 차지하여 대부분의 경우 피크기의 유지시간은 2일 이내이다. 초강력 태풍은 주로 9월에 발생하고 5월, 8월, 10월에도 높은 빈도수를 보여 이 시기에 발생하는 태풍에 대하여 각별히 주의할 필요가 있다.