• 보존과학연구
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• 통권19호
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• pp.35-60
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• 1998

Cultural properties are valuable objects, which have exposed insevere environment and inherited for a long time but we don’t have correct information concerning materials, structure and skill of manufacture. Because the cultural properties have been destroyed by the deterioration elements as like wind, this must be carefully treated for investigation of exhibition and storage. Even if the observation is scientific research, we must not take actual sample from the object for obtaining information concerning the nature materials and skill of manufacture. so it is elementary principle to use non-destructive investigation method as analytical methods for cultural property. This contribution discusses the present condition and problem of X-ray fluorescence acting as a representative non-destructive investigation method and the difference of statistics to be connected with determination and finally explains the intend facts for analysis of data.

• 아시안잔디학회지
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• 제10권1호
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• pp.31-40
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• 1996

The mechanical expresion provides for the use of Soil property reserves and permanent protec-tion or improvement of soil resources in accordance with measurable standards. If the functions I (initial soil property), E (soil erosion), R (soil renewal), and M. (minimum allowable value) are assumed to be integrable in region A, erosion tolerance over a region is leaded to ${\int}_A{\int}I(m, cl, re, ch, b)dA-{\int}_A{\int}{\{\int}_{to}^{\infty}[E(w, re, c, re, ch, b, t)-R(m, ch, re, b, t)]dt}\dA{\geqq}{\int}_A{\int}M_i(m, cl, re, ch, b)dA$ were variable factors are m=parent material of soil, cl=climate, re=relief or topography, ch=soil characteristics, r=rain or water, w=wind, b=biota, and t=time.

• 한국안전학회지
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• 제9권1호
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• pp.61-67
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• 1994

Rate of rise heat detectors that respond to the heat generated in fire plume and alarm when the temperature reaches a specified point, give a great influences to the loss of life and property according to their reaction sensitivity. In this study, simple equations were derived which can be predicted the response time and temperature of the rate of rise heat detector with the results of hot wind tunnel tests and compartment fire experiments.

• 대한조선학회지
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• 제12권1호
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• pp.83-90
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• 1975

In order to establish a stability and buoyancy criteria of a floating vessel, the geometrical property as well as external forces and moments be dealt with. This paper discusses in general terms hidden but more salient factors of forces and moments of both natural and artificial origin, particularly wind, with regard to vessels of more general type such as oil drilling rigs.

• Journal of Electrical Engineering and Technology
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• 제10권5호
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• pp.1969-1982
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• 2015

The virtual inertia control (VIC) of wind turbine with directly-driven permanent-magnet synchronous generator (D-PMSG) can act similarly to the conventional synchronous generator in inertia response and frequency control, thereby supporting the system frequency stability. However, because the wind speed is inconstant and changeable to a certain extent and the D-PMSG is a complex nonlinear system, there are great difficulties in the virtual inertia optimal control of the D-PMSG. Based on the design principle of the active disturbance rejection control (ADRC), this paper presents a new VIC strategy for the D-PMSG from the perspective of power disturbance suppression in the system. The strategy helps fulfill the power grid disturbance estimation and compensation by means of the extended state observer (ESO) so as to improve the disturbance-resisting performance of the system. Compared with conventional proportional-derivative virtual inertia control (PDVIC), this method, which is of better adaptability and robustness, can not only improve the property of the D-PMSG responding to the system frequency but also reduce the influence of wind speed disturbance. The simulation and experiment results have verified the effectiveness and feasibility of the VIC based on the ADRC.

• Ocean and Polar Research
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• 제32권2호
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• pp.97-111
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• 2010

Phytoplankton production is affected by various physico-chemical factors of environment. However, one of the most critical factors generally accepted as controlling primary production of phytoplankton is nutrients. It has recently been found that the succession of phytoplankton groups and species are closely related to the chemical properties of ambient water including nutrient limitation and their ratios. In Jangmok Bay, silicate and nitrate are primarily supplied by rainfall, while phosphate and ammonia are supplied by wind stress. Typhoons are associated with rainfall and strong wind stress, and when typhoons pass through the South Sea, such events may induce phytoplankton blooms. When nutrients were supplied by heavy rainfalls during the rainy season and by summer typhoons in Jangmok Bay, the dominant taxa among the phytoplankton groups were found to change successively with time. The dominant taxon was changed from diatoms to flagellates immediately after the episodic seasonal events, but returned to diatoms within 3~10 days. Pseudo-nitzschia spp. were dominant mainly in the presence of low phosphate levels during the first of the survey which included the rainy season, while Skeletonema costatum was dominant when phosphate concentrations were high due to the strong wind stress during the latter half of the survey as a result of the typhoon. The competition between S. costatum and Chaetoceros spp. appeared to be regulated by the silicate concentration. S. costatum preferred high silicate and phosphate concentrations; however, Chaetoceros spp. were able to endure low silicate concentrations. These results implied that, in coastal ecosystems, the input patterns of each nutrient supplied by rainfall and/or wind stress appeared to contribute to the summer succession of phytoplankton groups and species.

• 한국산학기술학회논문지
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• 제19권2호
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• pp.668-675
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• 2018

전 세계적으로 도시화와 산업화의 발달은 많은 양의 전력을 필요로 하였다. 그리하여 연안 지역에 원자력 발전소를 비롯한 주요 사회기반시설의 건설이 가속화되었다. 또한 지구 온난화와 이상 기후 현상에 의해 자연 재해의 강도는 증가하고 있다. 자연 재해는 발생 지점과 규모를 예측하기 어렵고, 인명 피해와 재산 피해에 영향을 주고 있다. 이러한 문제로 인하여 연안 지역의 피해 예측과 재해 규모의 산정은 중요한 문제가 되었다. 그리하여 본 연구에서는 예측 가능한 기상 자료를 바탕으로 풍랑 피해의 피해액을 예측하고 예측한 결과를 바탕으로 풍랑 피해에 대하여 사전 대비 차원의 재난 관리가 가능할 것이라 판단된다. 본 연구에서는 재해 통계 자료가 부족한 시 군 구는 인접한 기상 관측소의 자료를 활용하는 지역은 군집분석을 활용하였다. 예측 가능한 기상자료와 지역 등급을 반영하였고, 재해 통계를 기반으로 남해연안지역의 풍랑 피해 예측함수를 개발 하였고, 검증 작업으로는 NRMSE를 활용하였다. 그 결과 NRMSE는 1.61%에서 21.73%로 분석되었다.

• 한국지구과학회지
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• 제24권4호
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• pp.325-336
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• 2003

관측지점의 위치를 살펴보면 해안으로부터 수영은 약 5m정도이고 해운대는 약 1km정도 떨어져 있다. 하지만 해운대에서의 해풍시작시간이 수영보다 빨리 나타난다. 따라서 국지순환모형인 LCM을 이용하여 수영과 해운대에서 해풍시작시간에 대한 지형의 효과를 수치모의 하였다. 이러한 현상은 야간의 복사냉각에 의해 형성된 흐름에 의한 것으로 분석되었는데, 도심지를 둘러싸고 있는 고지대의 경사면을 따라서 수렴된 공기가 가장 저지대인 수영지역으로 흘러가기 때문에 나타난 것으로 이러한 현상은 일출 후에도 나타난다. AWS자료를 분석한 결과, 수영에서 해운대에 비해 약 3배정도 강한 강풍현상이 나타났는데, 이는 수영지역이 야간공기의 유출구이기 때문이다. 이를 통해 지형조건이 해풍의 시작에 중요한 역할을 한다는 것을 알 수 있었다.

• 한국구조물진단유지관리공학회 논문집
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• 제16권2호
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• pp.87-94
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• 2012

본 연구에서는 풍력발전기 타워의 효과적인 상태 모니터링을 위하여 타워의 고유진동수 및 모드형상을 이용한 손상추정기법을 제안하였다. 풍력발전기에 대한 동력학 시뮬레이션 프로그램을 이용하여 타워의 거동을 시뮬레이션하고 결과를 이용하여 타워의 모드특성을 추정하였다. 다양한 손상에 의한 타워의 고유진동수와 모드형상의 변화를 모드특성 추정 프로그램을 이용하여 해석적으로 구하여 훈련패턴을 생성하고 이를 이용하여 신경망을 훈련시켰다. 복수 손상 경우를 포함한 10가지 손상경우에 대한 모드특성을 훈련된 신경망에 입력하여 손상을 추정하였으며, 모든 손상 경우에 대하여 비교적 정확하게 손상위치와 손상정도를 판정할 수 있었다. 단, 미소 손상의 경우 손상정도가 약간 과소평가되는 경향을 보였으나 손상위치는 합리적으로 추정됨을 알 수 있었다. 향후, 미소 손상 추정결과의 정확성을 개선하고, 실험을 통하여 제안된 기법을 검증할 계획이다.

• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.443-449
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• 2022

With climate change and the global population growth, the frequency and scope of wildfires are constantly increasing, which threatened people's lives and property. For example, according to California Department of Forestry and Fire Protection, in 2020, a total of 9,917 incidents related to wildfires were reported in California, with an estimated burned area of 4,257,863 acres, resulting in 33 fatalities and 10,488 structures damaged or destroyed. At the same time, the ongoing development of technology provides new tools to simulate and analyze the spread of wildfires. How to use new technology to reduce the losses caused by wildfire is an important research topic. A potentially feasible strategy is to simulate and analyze the spread of wildfires through computing technology to explore the impact of different factors (such as weather, terrain, etc.) on the spread of wildfires, figure out how to take preemptive/responsive measures to minimize potential losses caused by wildfires, and as a result achieve better management support of wildfires. In preparation for pursuing these goals, the authors used a powerful computing framework, Spark, developed by the Commonwealth Scientific and Industrial Research Organization (CSIRO), to study the effects of different weather factors (wind speed, wind direction, air temperature, and relative humidity) on the spread of wildfires. The test results showed that wind is a key factor in determining the spread of wildfires. A stable weather condition (stable wind and air conditions) is beneficial to limit the spread of wildfires. Joint consideration of weather factors and environmental obstacles can help limit the threat of wildfires.