• 한국농림기상학회지
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• 제18권3호
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• pp.162-169
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• 2016

기준기상위험이란 한 지역의 평년기후조건이 작물재배에 미칠 수 있는 '농업기상학적 피해가능성'으로서, 동일 작물 재배 시 지역에 따른 재해위험을 비교하는 기준이 된다. 지구온난화로 인하여 겨울 온도는 상승할 것으로 예상되지만, 기상이변의 빈도 또한 늘어날 것으로 전망되기 때문에 미래 기후조건에서 과수의 동해, 상해 등 저온에 의한 재해위험이 주목 받고 있다. 그러나 기후의 변화는 과수 생물계절도 변화시키므로 기상조건에 근거한 단순한 재해위험 전망은 기후변화적응의 실용측면에서 별 도움이 되지 못한다. 본 연구에서는 전국 주요 지역의 과거 및 기후변화시나리오를 이용하여 배, 복숭아, 사과의 생물계절을 예측하고 생육단계별 기온과의 상호작용에 근거하여 저온 유래 기준기상위험을 계산함으로써 미래의 재해가능성을 전망하였다. 휴면해제일은 미래로 갈수록 늦어질 것으로 전망되었으며, 발아일과 개화일의 경우 빨라질 것으로 예상되었다. 대구, 전주, 목포의 경우 휴면해제일의 지연 정도가 미래로 갈수록 커졌으며 발아일과 개화일의 경우 서울, 인천 지역이 다른 지역에 비해 늦게 나타났다. 서울과 인천, 대구와 전주, 부산과 목포가 서로 비슷한 양상을 나타내었다. 휴면기 동안에는 전 지역이 동해에 안전하였으나 휴면해제-발아기 동안에는 전 지역이 동해에 취약하였고, 발아기-개화기의 위험은 미래로 갈수록 대체로 낮아졌지만 지역에 따라 위험이 커지는 곳도 있었다.

• 대한토목학회논문집
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• 제44권3호
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• pp.291-302
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• 2024

가뭄 전이는 기상학적 가뭄이 오랜기간 지속되어 수문학적 가뭄으로 발달하는 현상으로 가뭄 전이 사상은 비전이 가뭄사상보다 지역에 큰 피해를 야기한다. 기존에 수행된 가뭄 전이 연구들은 주로 상관분석을 통해 지체시간을 파악하고 있으며, 가뭄 전이 및 비전이 사상 간의 피해 양상을 비교하는 연구는 부족한 실정이다. 본 연구에서는 충청권역 시군구 단위의 가뭄지수를 활용하여 기상학적 및 수문학적 가뭄간의 중복전이 및 풀링전이를 고려하여 가뭄 전이 여부를 판단하고, 가뭄의 전이 특성(풀링, 감쇠, 지체, 연장)을 분석하였다. 분석 결과 충청북도 충주시에서 2010년 기상학적 가뭄(비전이 사상)이 발생하였으나, 가뭄 피해는 발생하지 않았다. 하지만, 2017-2018년에 발생한 가뭄은 기상학적 가뭄이 수문학적 가뭄으로 전이되면서 심도는 약하지만 지속기간이 길어짐에 따라 가뭄으로 인한 피해가 발생하였다. 이와 비슷하게 2017년 청양군에서는 기상학적 가뭄(비전이 사상)이 발생하였으나, 가뭄 피해는 발생하지 않았다. 하지만, 바로 인접지역인 부여군에서는 동일한 기간에 비슷한 크기의 기상학적 가뭄이 수문학적 가뭄으로 전이되어 가뭄으로 인한 피해가 발생하였다. 본 연구를 통해 비전이 사상보다 전이 사상에서 피해가 심각한 것을 확인하였으며, 이러한 결과는 지역에 적합한 가뭄 대응 정책을 수립하는데 기초자료로 활용할 수 있다.

• 한국환경복원기술학회지
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• 제10권4호
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• pp.41-53
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• 2007

The Baekdudaegan Mountain Range is a backbone of the Korean Peninsula which carries special spiritual and sentimental signatures for Koreans as well as significant ecological values for diverse organisms. However, in spite of importance of this region, the forests of Baekdudaegan have been damaged in a variety of human activities by being used as highland vegetable grower, lumber region, grass land, and bare land, and are still undergoing destruction. The existing researches had determined the details of the damage through on-site and recent observations. Such methods cannot provide quantitative and integrated analysis therefore could not be utilized as objective data for the ecological conservation of Baekdudaegan forests. The goal of this study is to quantitatively analyze the forest damage in the Baekdudaegan preservation region through land cover categorization and change detection techniques by using satellite images, which are 1980s, and 1990s Landsat TM, and 2000s Landsat ETM+. The analysis was executed by detecting land cover changed areas from forest to others and analyzing changed areas' spatial patterns. Through the change detection analysis based on land cover classification, we found out that the deforested areas were approximately three times larger after the 1990s than from the 1980s to the 1990s. These areas were related to various topographical and spatial elements, altitude, slope, the distance form road, and water system, etc. This study has the significance as quantitative and integrated analysis about the Baekdudaegan preservation region since 1980s. These results could actually be utilized as basic data for forest conservation policies and the management of the Baekdudaegan preservation region.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 추계학술대회 초록집
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• pp.189.2-189.2
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• 2010

The purpose of this study is fatigue damage assessment for large sized casting parts (hub and mainframe) of the 3MW offshore wind turbine by computer simulation. Hub and mainframe durability assessment is necessary because wind turbine have to guarantee for 20 years. Fatigue life evaluation must be considered all of fatigue load conditions as the components are wind load transmission path. Palmgren-Miner linear damage accumulation hypothesis is applied for fatigue life estimation with stress-life approach. S-N curve for the spheroid graphite cast iron EN-GJS-400-18-LT is derived according to durability guidelines. Reduction factors were applied for survival probability, surface roughness, material quality and partial safety factor according to Germanischer Lloyd rules. To calculate fatigue damage, stress tensors, extracted from the unity load calculation from ANSYS is multiplied with time track of fatigue loads extracted from GH bladed. Damage accumulation is performed with all of fatigue load conditions at each finite element nodes. In this study maximum nodal damage value is under 1.0. casted parts are safe. This research was financially supported by the Ministry of Knowledge Economy(MKE), Korea Institute for Advancement of Technology(KIAT) and Honam Leading Industry Office through the Leading Industry Development for Economic Region.

• Interaction and multiscale mechanics
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• 제2권2호
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• pp.153-175
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• 2009

Damage detection methods using structural dynamic responses have received much attention in the past decades. For bridge and offshore structures, these methods are usually based on beam models. To ensure the successful application of these methods, it is necessary to examine the sensitivity of modal properties to structural damages. To this end, an analytic solution is presented of the modal properties of simply-supported Euler-Bernoulli beams that contain a general damage with no additional assumptions. The damage can be a reduction in the bending stiffness or a loss of mass within a beam segment. This solution enables us to thoroughly discuss the sensitivities of different modal properties to various damages. It is observed that the lower natural frequencies and mode shapes do not change so much when a section of the beam is damaged, while the mode of rotation angle and curvature modes show abrupt change near the damaged region. Although similar observations have been reported previously, the analytical solution presented herein for clarifying the mechanism involved is considered a contribution to the literature. It is helpful for developing new damage detection methods for structures of the beam type.

• Earthquakes and Structures
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• 제25권3호
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• pp.209-221
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• 2023

The Mw=7.7 (Pazarcık-Kahramanmaraş) and Mw=7.6 (Elbistan-Kahramanmaraş) earthquakes that occurred in Türkiye on 06.02.2023 with 9 hours' intervals, caused great losses of life and property as the biggest catastrophe in the instrumental period. The earthquakes affecting an area of 14% of the country were enormous and caused a great deal of loss of life and damage. Numerous buildings have collapsed or damaged at different levels, both in the city centers and in rural areas. Within the scope of this study, masonry structure damage built from different types of materials in the earthquake region was taken into consideration. In this study, the damage and causes of such masonry structures that do not generally receive engineering services were examined and explained in detail. Insufficient interlocking between wall-wall and wall-roof, inadequate masonry, lack of horizontal and vertical bond beams, usage of low-strength materials, poor workmanship, and heavy earthen roof are commonly caused to structural damages. Separation at the corner point and out-of-plane mechanism in structural walls, and heavy earthen roof damages are common types of damage in masonry structures.

• 국제학술발표논문집
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• The 6th International Conference on Construction Engineering and Project Management
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• pp.339-343
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• 2015

To rapidly recover ceased functionality of a facility after a catastrophic seismic event, critical decisions on facility repair works are made within a limited period of time. However, prolonged damage assessment of facilities, due to massive damage in the surrounding region and the complicated damage judgment procedures, may impede restoration planning. To assist reliable structural damage estimation without a deep knowledge and rapid interactive analysis among facility damage and restoration operations during the approximate restoration project planning phase, we developed a prototype of distributed facility restoration simulations through the use of high-level architecture (HLA) (IEEE 1516). The simulation prototype, in which three different simulations (including a seismic data retrieval technique, a structural response simulator, and a restoration simulation module) interact with each other, enables immediate damage estimation by promptly detecting earthquake intensity and the restoration operation analysis according to estimated damage. By conducting case simulations and experiments, research outcomes provide key insights into post-disaster restoration planning, including the extent to which facility damage varies according to disaster severity, facility location, and structures. Additional insights arise regarding the extent to which different facility damage patterns impact a project's performance, especially when facility damage is hard to estimate by observation. In particular, an understanding of required type and amount of repair activities (e.g., demolition works, structural reinforcement, frame installation, or finishing works) is expected to support project managers in approximate work scheduling or resource procurement plans.

• 한국초지조사료학회지
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• 제43권3호
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• pp.190-198
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• 2023

This study was conducted to calculate the damage of Italian ryegrass (IRG) by abnormal climate using machine learning and present the damage through the map. The IRG data collected 1,384. The climate data was collected from the Korea Meteorological Administration Meteorological data open portal.The machine learning model called xDeepFM was used to detect IRG damage. The damage was calculated using climate data from the Automated Synoptic Observing System (95 sites) by machine learning. The calculation of damage was the difference between the Dry matter yield (DMY)_normal and DMY_abnormal. The normal climate was set as the 40-year of climate data according to the year of IRG data (1986~2020). The level of abnormal climate was set as a multiple of the standard deviation applying the World Meteorological Organization (WMO) standard. The DMY_normal was ranged from 5,678 to 15,188 kg/ha. The damage of IRG differed according to region and level of abnormal climate with abnormal temperature, precipitation, and wind speed from -1,380 to 1,176, -3 to 2,465, and -830 to 962 kg/ha, respectively. The maximum damage was 1,176 kg/ha when the abnormal temperature was -2 level (+1.04℃), 2,465 kg/ha when the abnormal precipitation was all level and 962 kg/ha when the abnormal wind speed was -2 level (+1.60 ㎧). The damage calculated through the WMO method was presented as an map using QGIS. There was some blank area because there was no climate data. In order to calculate the damage of blank area, it would be possible to use the automatic weather system (AWS), which provides data from more sites than the automated synoptic observing system (ASOS).

• Journal of Photoscience
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• 제9권2호
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• pp.454-456
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• 2002

It is important to determine the action spectrum of UV-B radiation contained in the sunlight to estimate the risk of skin cancer. We have investigated action spectra for induction of apoptosis and reproductive cell death in L5178Y cells using the Okazaki Large Spectrograph at NIBB. L5178Y cells were exposed to light at different wavelengths in UV-B or UV-A region. Frequencies of apoptosis induction and reproductive cell death were determined by counting cells with chromatin condensation, and by the colony formation assay, respectively. The measured sensitivity spectra for the two end-points were in very good agreement. Sensitivity decreased steeply with increase of wavelength in UV-B region and remains nearly constant in UV-A region. The action spectra were also slightly steeper than that for the minimum erythematic dose (MED), but very similar to the light absorption spectrum of DNA in UV-B region. On the other hand, the spectra for both endpoints were similar to MED spectrum but not DNA spectrum in the UV-A region. Also different time-course and morphological difference of apoptosis were found between UV-B (long time, fragmentation) and UV-A (short time, shrinkage) region. These results suggest that DNA damage induced by UV-B light triggers apoptosis and reproductive cell death, but other damaged targets (membrane, protein and so on) trigger these effects in UV-A region.

• Journal of Forest and Environmental Science
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• 제32권4호
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• pp.384-391
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• 2016

In this study, regions infected by pine wilt disease were extracted by using object-based classification method (OB-infected region), and the characteristics of special distribution about OB-infected region were figured out. Scale 24, Shape 0.1, Color 0.9, Compactness 0.5, and Smoothness 0.5 was selected as the objected-based, optimal weighted value of OB-infected region classification. The total accuracy of classification was high with 99% and Kappa coefficient was also high with 0.97. The area of OB-infected region was approximately 90 ha, 16% of the total area. The OB-infected region in Age class V and VI was intensively distributed with 97% of the total. Also, The OB-infected region in Middle and Large DBH class was intensively distributed with 99% of the total. In terms of the topographic characteristics of OB-infected region, the damages occurred approximately 86% below the altitude of 200 m, and occurred 91% with a slope less than 10 degree. The damage occurred a lot in low hilly mountain and undulating slope. In addition, the accessibility to road and residential area from OB-infected region was less than 300 m in large part. Overall, it was figured out that artificial effect is stronger than natural effect with regard to the spread of pine wilt disease.