• Proceedings of the Korean Environmental Sciences Society Conference
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• 1994.04a
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• pp.83-83
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• 1994

• Journal of the Korean earth science society
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• v.21 no.1
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• pp.40-40
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• 2000

After analyzing the record of climate of the Chosun era with the weather data written on the true history of the Chosun Dynasty, and in comparison with the latest weather data in Seoul, the following conclusion has been reached. It s not easy to restore the climate of the Chosun era with the true history of the Chosun Dynasty only, for the data of the Chosun era is nothing but 5.4% of that the recent 10 years, centering around Seoul. The number of days of the praying for rain and fine weather have nothing to do with those of precipitation. The monthly number of days of precipitation and hail are similar to those of the recent 10 years, even though the data is not enough. The situation of the days of frost and fog are very different from that of the recent ,10 years. This suggests that they recorded the situation when there was a lot of casualties to men and property, while they didn't record it when there were no casualties because the precipitation occured at the time.

• Journal of the Korean earth science society
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• v.21 no.1
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• pp.41-50
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• 2000

After analyzing the record of climate of the Chosun era with the weather data written on the true history of the Chosun Dynasty, and in comparison with the latest weather data in Seoul, the following conclusion has been reached. It's not easy to restore the climate of the Chosun era with the true history of the Chosun Dynasty only, for the data of the Chosun era is nothing but 5.4% of that the recent 10 years, centering around Seoul. The number of days of the praying for rain and fine weather have nothing to do with those of precipitation. The monthly number of days of precipitation and hail are similar to those of the recent, years, even though the data is not enough. The situation of the days of frost and fog are very different from that of the recent.10 years. This suggests that they recorded the situation when there was a lot of casualties to men and property, while they didn't record it when there were no casualties because the precipitation occured at the time.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.5
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• pp.110-116
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• 2003

With the growth of aircraft performance and needs for light aircraft, the problems associated with hail impacts on aircraft during flights and grounding become and important issue. These hail encounters can cause severe damages to aircraft and result in major concerns in safety and cost. Since nearly all external components of the commercial and military aircraft-in particular, the nose section and the leading edge of the wing and tail-are subject to damages, much effort has been put into understanding of this problem. However, most of the previous studies have focused on the composite components and few results have been reported for the metallic components. In this paper, we study the ice impacts on the aluminum component with the finite element analysis method utilizing commercial non-linear dynamics solver LS-DYNA. The results are compared with the experimental data and a simple measure of the ice impact effects is proposed.

• 농업기술회보
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• v.49 no.4
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• pp.24-25
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• 2012

최근 한반도의 기후변화 진행속도는 세계평균의 2배 이상을 웃돌며 외국에 비해 기상재해 발생 가능성이 증가하고 있다. 태풍, 집중호우 등 풍수해가 증가하면서 상시화되는 경향을 보이며 강수량 증가로 호우피해가 확대되고 있다. 1월 한파, 2~3월에는 일조부족, 3~4월 저온, 5~6월 우박과 강수랑 부족으로 일부지역에서 농작물 가뭄피해가 발생했다. 여름철을 맞아 집중호우, 태풍, 폭염에 대비한 농작물 관리요령을 알아보자.

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.267-270
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• 1998

Unequal wheel-radius causes odometry errors which may be increased unbounded. This paper deals with the practical method for modification of wheel-radius through experiments. This can increase the robot's odometric accuracy. Experimental results are presented that show improvement of odometric accuracy.

• Journal of the Korean Solar Energy Society
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• v.40 no.4
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• pp.23-33
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• 2020

The loss in photovoltaic power due to hailstorms has been highlighted as a major issue in the sustained growth of the PV power plant industry. This study investigates the safety of a solar module by conducting a numerical analysis of a hail test according to the IEC 61215 standard. Our study aims to elucidate the detailed behavior between the ice and solar modules and the micro-cracks forming on solar modules during hailstorms. To analyze the impact of hail, we used the ANSYS AUTODYN software to evaluate the impact characteristics on a solar module with different front glass thicknesses. The simulations show that a solar module with a glass thickness of 4.0 mm results in excellent durability against hail. The results indicate the feasibility of using simulations to analyze and predict micro-cracks on solar modules tailored to various conditions, which can be used to develop new solar modules.

• Korean Journal of Environmental Agriculture
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• v.33 no.4
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• pp.321-326
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• 2014

BACKGROUND: Recently, weather disasters such as hail and typhoon occur frequently. These threaten the stable cultivation of potatoes. It is very important to cultivate potatoes with stable under unexpected weather disasters. This study was performed to investigate the correlation between mophological characteristics of potato stem and its resistance to hail damage in different potato cultivars. METHODS AND RESULTS: Hail fall occurred for 8 minutes on May 31, 2012 in the field of Highland Agriculture Research Center located in Jinbu-myeon Gangwon-do. Potato crop grown in the field was affected by hail due to which the stems of potato were broken. The percentage of broken stem of potato was investigated as the level of damage by hail. To determine the difference in the ratio of broken stem among the potato cultivars, physical characteristics of potato stem such as diameter and hardness were measured. To evaluate recovery phase after hail damage, ground coverage and yield were measured. The percentage of broken stem of cv. Goun and cv. Saebong were 30%, 26%, respectively, whereas it was 5% in the cv. Atlantic. Damage by hail was the lowest in cv. Atlantic. Diameter of the stem was 15 mm in cv. Atlantic, 13 mm in cv. Goun and 11 mm in cv. Saebong. The hardness of potato cultivars was measured which was 74 N in cv. Atlantic. 71 N in cv. Goun and 59 N in cv. Saebong. The ground coverage in cv. Atlantic was 79%, which was the highest followed by 73% in cv. Saebong and 56% in cv. Goun. The yield of cv. Atlantic was monitored at 90 days after planting which was 40 MT/ha and that of cv. Saebong was 36 MT/ha, whereas in cv. Goun, it was 30 MT/ha which was the lowest. CONCLUSION: The ratio of broken stem in cv. Atlantic was the lowest compared to cultivars. In the physical characteristics of stem, cv. Atlantic was the highest in value of diameter and hardness. Based on these results, it was considered that cv. Atlantic was resistant to hail damage compared to other cultivars.

• Journal of the Korean earth science society
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• v.18 no.6
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• pp.565-578
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• 1997

Clouds are usually formed by adiabatic cooling through ascending currents, radiation cooling or a mixture of warm air and cold one. Ascending currents are caused by covection currents, or they are accompanied with fronts. Thus clouds are formed through various kinds of causes and procedures. So they are various in height and shape. Form of clouds was classified on the basis of the thecriteria that L. Howard proposed in 1803. He distinguished three simple, fundamental classes-Cirrus, Cumulus, Stratus-from which the others were derived by trasition or association. And they are subdivided into 10 genera according to their height and shape. Most of the clouds are subdivided into the detailed kinds to the characteristics such as appearance or intensity of convection current. Sometimes completly different shape of cloud can be developed out of the 'mother-cloud'. In korea, the stratocumulus, altostratus and cirrus clouds frequently appear. Generally we are likely to have rain or snow from the stratus cloud forms(As, St, Sc) and rain shower or hail from the cumulus forms(Ac, Cu, Cb).

• 한국방재학회:학술대회논문집
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• 2007.02a
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• pp.81-84
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• 2007

Data for occurrence of hail over Korean Peninsula for the period 1961-2005 are obtained from the Korea Meteorological Administration (KMA). According to the average occurrences during each season in Korea Peninsular, hail days are almost distributed uniformly in the spring, fall and winter, except the summer and have averages of 5 days for each season. Analysis of regional occurrence of hail shows that inland of Korea Peninsular is vulnerable to hail in the spring and summer and the islands of Ullung, Baegryeong and Cheju and the coastal regions vulnerable in the fall and winter. It can be postulated that these seasonal patterns of hail is affected by the Monsoon effect.