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 DMYabnormal. 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 DMYnormal 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).

Recently, the importance of impact-based forecasting has increased along with the socio-economic impact of severe weather have emerged. As news articles contain unconstructed information closely related to the people’s life, this study developed and evaluated a binary classification algorithm about snowfall damage information by using media articles text mining. We collected news articles during 2009 to 2021 which containing ‘heavy snow’ in its body context and labelled whether each article correspond to specific damage fields such as car accident. To develop a classifier, we proposed a probability-based classifier based on the ratio of the two conditional probabilities, which is defined as I/O Ratio in this study. During the construction process, we also adopted the n-gram approach to consider contextual meaning of each keyword. The accuracy of the classifier was 75%, supporting the possibility of application of news big data to the impact-based forecasting. We expect the performance of the classifier will be improve in the further research as the various training data is accumulated. The result of this study can be readily expanded by applying the same methodology to other disasters in the future. Furthermore, the result of this study can reduce social and economic damage of high impact weather by supporting the establishment of an integrated meteorological decision support system.

Cnidium officinale M. is an important crop that is widely used as a raw material for health functional foods. However, it is experiencing cultivation difficulties due to climate change and abnormally high temperatures. In response to this problem, the characteristics and main causes of the high-temperature damage occurring in C. officinale M. cultivation fields were analyzed. A survey of five farmhouse fields in Jecheon and Bonghwa, major C. officinale M. cultivation areas in Korea in 2018, indicated that about 5% to 37% of the cultivation fields in Jecheon and 5% to 15% of the fields in Bonghwa died from wilting. The high-temperature damage of the C. officinale M. fields is divided into two categories: upper leaves drying due to solar radiation and temperature, and lower leaves dying serially to the radiant heat of the vinyl mulch. Damage caused by radiant heat was typically greater. This is due to the greenhouse effect that occurs in the small space between the black vinyl mulching and the soil. The heat radiated to the surface of the ridge creating an environmental condition that greatly exceeded the atmospheric temperature especially on hot days. As a result, short plants with underground parts, such as C. officinale M., can suffer more high-temperature damage than other plants, so it is considered that it is necessary to develop related technologies such as mulching materials that can reduce pavement temperature in the future.

This study was conducted with the aim of confirming the impact and relative contribution of extreme weather to dry matter yield (DMY) of silage corn in the central inland region of Korea. The corn data (n=1,812) were obtained from various reports on the new variety of adaptability experiments conducted by the Rural Development Administration from 1978 to 2017. As for the weather variables, mean aerial temperature, accumulated precipitation, maximum wind speed, and sunshine duration, were collected from the Korean Meteorological Administration. The extreme weather was detected by the box plot, the DMY comparison was carried out by the t-test with a 5% significance level, and the relative contribution was estimated by R2 change in multiple regression modeling. The DMY of silage corn was reduced predominantly during the monsoon in summer and autumn, with DMY damage measuring 1,500-2,500 kg/ha and 1,800 kg/ha, respectively. Moreover, the relative contribution of the damage during the monsoons in summer and autumn was 40% and 60%, respectively. Therefore, the impact of autumn monsoon season should be taken into consideration when harvesting silage corn after late August. This study evaluated the effect of extreme weather on the yield damage of silage corn in Korea and estimated the relative contribution of this damage for the first time.

본 논문에서는 다중 시그마포인트 세트(MSP)를 사용하는 분산점 칼만필터(UKF)인 UKF-MSP를 소개한다. 비선형 동적시스템을 표현하기 위해 널리 알려진 Bouc-Wen 모델을 사용하였고, 비선형성 고려가 가능한 칼만필터 중 UKF를 선정하였다. 그런데 UKF는 두 가지 인공오차와 시그마포인트의 분포를 결정하는 스케일링 파라미터의 값을 튜닝(Tuning)하는 과정을 통해 적절히 설정해야만 대상 동적시스템의 추정하고자 하는 상태(State)를 정확히 추정할 수가 있다. 본 논문에서는 후자의 스케일링 파라미터 설정 문제를 완화하고자 하였으며, MSP를 사용함으로써 기존 UKF에 비해 칼만필터 튜닝 과정에 덜 민감한 UKF-MSP를 제안하였다. 지진으로 인한 급격한 구조손상 시나리오에 대해 UKF-MSP의 안정성을 검증하였다. 제안된 방법은 튜닝과정을 완화함과 동시에 다른 칼만필 터 파라미터인 인공오차에 대해서도 덜 민감한 거동을 보임을 확인하였다.

In this study, the physical properties and fracture characteristics according to the tensile load are evaluated on the materials of the polymeric filler and carbon fiber-based composite sleeve technique. The polymeric filler and the composite sleeve technique are applied to areas where the pipe body thickness is reduced due to corrosion in large-diameter water pipes. First, the tensile strength of the polymeric filler was 161.48~240.43 kgf/cm2, and the tensile strength of the polyurea polymeric filler was relatively higher than that of the epoxy. However, the tensile strength of the polymeric filler is relatively very low compared to ductile cast iron pipes(4,300 kgf/cm2<) or steel pipes(4,100 kgf/cm2). Second, the tensile strength of glass fiber, which is mainly used in composite sleeves, is 3,887.0 kgf/cm2, and that of carbon fiber is up to 5,922.5 kgf/cm2. The tensile strengths of glass and carbon fiber are higher than ductile cast iron pipe or steel pipe. Third, when reinforcing the hemispherical simulated corrosion shape of the ductile cast iron pipe and the steel pipe with a polymeric filler, there was an effect of increasing the ultimate tensile load by 1.04 to 1.06 times, but the ultimate load was 37.7 to 53.7% compared to the ductile cast iron or steel specimen without corrosion damage. It was found that the effect on the reinforcement of the corrosion damaged part was insignificant. Fourth, the composite sleeve using carbon fiber showed an ultimate load of 1.10(0.61T, 1,821.0 kgf) and 1.02(0.60T, 2,290.7 kgf) times higher than the ductile cast iron pipe(1,657.83 kgf) and steel pipe(2,236.8 kgf), respectively. When using a composite sleeve such as fiber, the corrosion damage part of large-diameter water pipes can be reinforced with same level as the original pipe, and the supply stability can be secured through accident prevention.

This study aims to analyze the cost of climate change damages to laver and sea mustard aquaculture, which are considered to be highly vulnerable to climate change in Korea. For this purpose, the correlation between aquaculture production and climate factors such as water temperature, salinity, air temperature, and precipitation was estimated using a panel regression model. The SSP scenario was applied to predict the changes in production and damage costs due to changes in future climate factors. As a result of the analysis, laver production is predicted to decrease by 18.0-27.2% in 2050 and 20.6-61.6% in 2100, and damage costs are predicted to increase from 29.7-50.8 billion KRW in 2050 to 35.7-116.1 billion KRW in 2100. Sea mustard production is projected to decrease by 24.5-37.2% in 2050 and 24.0-34.5% in 2100, with similar damage costs of 41.1-61.8 billion KRW and 41.1-58.6 billion KRW, respectively. These damage costs are expected to occur in the short term as damage caused by fishery disasters such as high temperatures, and in the long term as a decrease in production due to changes in aquaculture sites. Therefore, measures such as strengthening the forecasting system to prevent high-temperature damage, developing high-temperature-resistant varieties, and relocating fishing grounds in response to changes in aquaculture sites will be necessary.

Al-B4C neutron absorbers are currently widely used to maintain the subcriticality of both wet and dry storage facilities of spent nuclear fuel (SNF), thus long-term and high-temperature material integrity of the absorbers has to be guaranteed for the expected operation periods of those facilities. Surface corrosion solely has been the main issue for the absorber performance and safety; however, the possibility of irradiation-assisted degradation has been recently suggested from an investigation on Al-B4C surveillance coupons used in a Korean spent nuclear fuel pool (SFP). Larger radiation damage than expectation was speculated to be induced from 10B(n, α)7Li reactions, which emit about a MeV α-particles and Li ions. In this study, we experimentally emulated the radiation damage accumulated in an Al-B4C neutron absorber utilizing heavy-ion accelerator. The absorber specimens were irradiated with He ions at various estimated system temperatures for a model SNF storage facility (room temperature, 150, 270, and 400°C). Through the in-situ heated ion irradiation, three exponentially increasing level of radiation damages (0.01, 0.1, and 1 dpa or displacement per atom) were achieved to compare differential gas bubble formation at near surface of the absorber, which could cause premature absorber corrosion and subsequential 10B loss in an SNF storage system. An extremely high radiation damage (10 dpa), which is unlikely achievable during a dry storage period, was also emulated through high temperature irradiation (350°C) to further test the radiation resistance of the absorber, conservatively. The irradiated specimens were characterized using HR-TEM and the average size and number density of radiation-induced He bubbles were measured from the obtained bright field (BF) TEM micrographs. Measured helium bubble sizes tend to increase with increasing system (or irradiation) temperature while decrease in their number density. Helium bubbles were found from even the lowest radiation damage specimens (0.01 dpa). Bubble coalescence was significant at grain boundaries and the irradiated specimen morphology was particularly similar with the bubble morphology observed at the interface between aluminum alloy matrix and B4C particle of the surveillance coupons. These characterized irradiated specimens will be used for the corrosion test with high-temperature humid gas to further study the irradiation-assisted degradation mechanism of the absorber in dry SNF storage system.

A literature study was conducted on the management of the pavilion of the royal tomb in the late Joseon Dynasty, focusing on “Gakneung Suri Deungnok(Records relating to the repair of royal tombs)”. This study analyzed the royal tomb management system, organized the types of damage identified in the building, and examined how the damage status was recorded by type. In the above, the records related to the 1675∼1713 repair of three JeongJaGak(Geonwonneung, Sungneung, and Mokneung), which are registered as state-designated cultural properties, are summarized in three aspects: management system, damage status, and expression words. The results of the study are as follows. First, the royal tomb pavilion was regularly inspected by Observator(觀察使) in spring and autumn, and Surunggwan(守陵官) every 5th, and Servant(守僕) regularly inspected every day and night, and also inspected and reported emergency cases of natural disasters or unexpected damage. Second, the damage status of each building was continuously observed and reported for the continuous maintenance of the buildings in the royal tomb. A total of 75 records of damage to the three royal tombs' pavilion were found to have been most frequently inspected, including 19 cases (25.3%), 14 cases (18.7%), 23 cases (30.7%) of the roof, and 19 cases (25.3%) of the roof. Third, the expression of the damage status is confirmed in various ways, such as separation, separation, burst, damage, excitation, moisture, leakage, and exfoliation. Among them, the main damage records were confirmed due to the separation of the base from the peeling, the furniture, cracks, leaks, leaks in the roof, and the collapse of the roof was able to check the damage records.