• Journal of agriculture & life science
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• v.53 no.2
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• pp.121-129
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• 2019

This study carried out to determine control factors for the improvement of productivity of laying hens suffering heat stress during hot weather. A total of 48,451 ISA Brown layers were housed in a farm located in Gyeongsangnam-do, Republic of Korea. Five thermo-hydrometer loggers were installed inside the house to collect data of dry-bulb temperature and relative humidity. The experiment continued for 81 days when the summer season begins from 19th June to 7th September, 2018. This study analyzed the correlations among layers' production index and daily average, highest, and lowest temperature; daily average, highest, and lowest relative humidity; and daily average, minimum, and maximum THI. The result indicated that feed consumption, hen-day egg production, egg weight, and FCR decreased as the daily average, highest and lowest dry-bulb temperature and THI rise (p<0.01). On the other hand, water intake increased as the daily average, highest and lowest dry-bulb temperature and THI rise (p<0.001). The relative humidity was not considered to have direct correlations to the layers' production index (p>0.05). However, it was noticeable that the mortality did not have significant relations with daily average and highest temperature; THI; or daily average, highest and lowest relative humidity while it was relevant to the daily lowest temperature and THI (p<0.05). In conclusion, to enhance the productivity of laying hens in a hot climate, it is recommended that daily average, highest, and lowest dry-bulb temperature and THI are maintained as low as possible. Especially, the daily lowest temperature is needed to lower to 20℃, which is the lowest critical temperature for layers.

• Journal of Korea Port Economic Association
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• v.37 no.4
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• pp.161-173
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• 2021

The shipping industry plummeted and was depressed due to the global economic crisis caused by the bankruptcy of Lehman Brothers in the US in 2008. In 2020, the shipping market also suffered from a collapse in the unstable global economic situation due to the COVID-19 pandemic, but unexpectedly, it changed to an upward trend from the end of 2020, and in 2021, it exceeded the market of the boom period of 2008. According to the Clarksons report published in May 2021, the decrease in cargo volume due to the COVID-19 pandemic in 2020 has returned to the pre-corona level by the end of 2020, and the tramper bulk carrier capacity of 103~104% of the Panamax has been in the ports due to congestion. Earnings across the bulker segments have risen to ten-year highs in recent months. In this study, as factors affecting BDI, the capacity and congestion ratio of Cape and Panamax ships on the supply side, iron ore and coal seaborne tonnge on the demand side and Granger causality test, IRF(Impulse Response Function) and FEVD(Forecast Error Variance Decomposition) were performed using VAR model to analyze the impact on BDI by congestion caused by strengthen quarantine at the port due to the COVID-19 pandemic and the loading and discharging operation delay due to the infection of the stevedore, etc and to predict the shipping market after the pandemic. As a result of the Granger causality test of variables and BDI using time series data from January 2016 to July 2021, causality was found in the Fleet and Congestion variables, and as a result of the Impulse Response Function, Congestion variable was found to have significant at both upper and lower limit of the confidence interval. As a result of the Forecast Error Variance Decomposition, Congestion variable showed an explanatory power upto 25% for the change in BDI. If the congestion in ports decreases after With Corona, it is expected that there is down-risk in the shipping market. The COVID-19 pandemic occurred not from economic factors but from an ecological factor by the pandemic is different from the past economic crisis. It is necessary to analyze from a different point of view than the past economic crisis. This study has meaningful to analyze the causality and explanatory power of Congestion factor by pandemic.

• Journal of Environmental Impact Assessment
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• v.32 no.1
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• pp.15-28
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• 2023

In the Republic of Korea, the target project scope of the small-scale EIA is stipulated as the plan area above around 5,000~60,000m² depending on a type of project and classification of land use. Whereas, the lower limit of the corresponding local government EIA project is generally located above the small-scale EIA's limits, and overlapping ranges exist. This situation has been enlarged since road construction and district unit planning were included as the target projects for small-scale EIA in the "Enforcement Decree of the Environmental Impact Assessment Act", which was partially revised in November 2016, and the current consultation system needed discussion in that small-scale EIA is allowed to be done without gathering review opinions at the local level. In fact, projects subjected to local government EIA but consulted as small-scale EIAs may seem insignificant because of a small number of total cases; however, it is worth paying attention to the fact that a local government may not add a target project due to the small-scale EIA. This study suggested the three policy measures for improving small-scale EIA to enhance the effectiveness of local government EIA: supplementing the institutional arrangements to incorporate the review opinion from the local region in small-scale EIA, giving priority to local EIA for conducing the projects in overlapping ranges with partial amendments on EIA law regarding exceptions to local government EIA, including small target projects (not to be small-scale EIA targets) to the ordinance that are deemed necessary to be conducted as local government EIA. Even though a positive function of small-scale EIA has been confirmed, efforts should be made to improve the situation in which many projects within local governments are consulted without review from the region.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.13 no.1
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• pp.42-55
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• 2008

To evaluate the accuracy of currents measured by HF radar in the coastal sea off Keum River estuary, we compared the facing radial vectors of two HF radars, and HF radar-derived currents with in-situ measurement currents. Principal component analysis was used to extract regression line and RMS deviation in the comparison. When two facing radar's radial vectors at the mid-point of baseline are compared, RMS deviation is 4.4 cm/s in winter and 5.4 cm/s in summer. When GDOP(Geometric Dilution of Precision) effect is corrected from the RMS deviations that is analyzed from the comparison between HF radar-derived and current-metermeasured currents, the error of velocity combined by HF radar-derived current is less than 5.1 cm/s in the stations having moderate GDOP values. These two results obtained from different method suggest that the lower limit of HF radar-derived current's accuracy is 5.4 cm/s in our study area. As mentioned in previous researches, RMS deviations become large in the stations located near the islands and increase as a function of mean distance from the radar site due to decrease of signal-to-noise level and the intersect angle of radial vectors. We found that an uncertain error bound of HF radar-derived current can be produced from the separation process of RMS deviations using GDOP value if GDOP value for each component is very close and RMS deviations obtained from current component comparison are also close. When the current measured in the stations having moderate GDOP values is separated into tidal and subtidal current, characteristics of tidal current ellipses analyzed from HF radar-derived current show a good agreement with those from current-meter-measured current, and time variation of subtidal current showed a response reflecting physical process driven by wind and density field.

• Bangmulgwan gwa yeongu (The National Museum of Korea Journal)
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• v.1
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• pp.96-119
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• 2024

Some inscribed bricks excavated from the western region of North Korea have been found bearing an era name used after 314 when the Nangnang and Daebang Commanderies had been completely ousted from the region. Others have been found with an era name used in the early fifth century. This indicates that the tradition of constructing brick chamber tombs was sustained for a century after the disappearance of the two commanderies. However, brick chamber tombs were never adopted as a burial system for the ruling class of the Goguryeo Kingdom. The Tomb of Jang Mui built in 348 and the Tomb of Dongni built in 353 both departed from the typical brick chamber tomb style of the region, and elements associated with stone chamber tombs were added to them. The Tomb of Dongsu (Anak Tomb No. 3), which is similar to the other two tombs in that its occupant is of Chinese descent, was constructed in 357 not as a brick chamber tomb, but as an earthen mound tomb with a stone chamber. Still, the continuation of brick chamber tomb tradition in the next half century has been somewhat puzzling. Although dated inscribed bricks have served as important evidence for understanding the continuation of the brick chamber tomb tradition, there has been a problem of continually repeating previous studies. It has also been pointed out that there was an error in the interpretation of era names in some of the dated inscribed bricks that had been believed to have been produced in or after 357. For example, "second year of Taean" (Taian in Chinese), which had been understood to correspond to 386 (during the Former Qin Dynasty), in fact refers to 303 (during the reign of Emperor Hui of the Western Jin Dynasty). In the case of "first year of Geonsi" (Jianshi in Chinese), which had been believed to indicate 407 (during the Later Yan Dynasty), it actually refers to 301. "Geonsi" is the era name used during the period when Sima Yun ousted Emperor Hui of the Western Jin Dynasty and briefly occupied imperial throne. Outside these two cases, the remaining dated inscribed bricks thought to have been produced in or after 357 are those dated to the "third year of Wonheung" (Yuanxing in Chinese). However, a reexamination of these bricks reveals that what is really "Yeongheung" (Yongxing in Chinese) has been misread as "Wonheung." The third year of Yeongheung corresponds to either 306 during the Western Jin Dynasty or 352 during the Later Zhao Dynasty, but it is highly probable that it refers to 306. This means that there is no conclusive evidence to support the hypothesis that brick chamber tombs were built in the area until the late fourth century and even into the early fifth. Accordingly, the Tombs of Jang Mui and Dongni should be viewed as the latest known brick chamber tombs to be constructed in the western region of North Korea. Moreover, brick chamber tombs appear to have been no longer built in the area around the time when the Tomb of Dongsu was constructed. These speculations accord with the historical circumstances of the time.

• Journal of Korean Historical Folklife
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• no.52
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• pp.7-46
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• 2017

The elderly in the Joseon Dynasty consistently attracted attention from the national herb as objects of social respect. Based on the Confucian ideology, the old man was considered to be a receiving body, since he was a person with complete character as a man. The elderly, who have the character of being a slave, transcended their status, and both the souls and the people were transcended beyond their identities and attributes and became objects of respect. The perception of the elderly is divided by age. The persons who are 50 years old and start to be in physical decline were regarded as senior citizens. However, this was just mentioned as an inflection point between the prime of manhood and senior citizens and was not defined as the elderly. As a public duty called a national work ends when they are 60 years old, the age is truly the lowest limit of senior citizens who are applicable to all the social beings. However, because their public duties end when they are 60 years old and they were regarded as general members of society, special benefits were not granted to them. In the caste system and bureaucratic society, senior citizens' treatment were differently done by age. For the senior citizens who are 70 years old, various benefits were just granted to high government officials. Bokho(復戶) and Seojeong were first given to them. And the retirement age of government officials was not specially set. It was done in the way to treat Jonno with exceptional respect by Chisa(致仕: regular retirement). It is the most respectful treatment given to high government officials and ministers. For the senior citizens who are 80 years old, Yangnoyeon(養老宴) was held for both of Yangmin and Cheonmin as an measure to treat them considerately. In addition, official ranks(官品) with social value were allowed by giving them Noinjik (老人職). Official ranks given to Seoin and Cheonin were the best Jonno(尊老) policy. However, the Jonno policy related to senior citizens was different according to position and official ranks as follows: Kings were subjected to social treatment when they were 60 years old. High government officials and royal relatives of the senior grade of the second court rank were subjected to social treatment when they were 70 years old. And general Seoin and slaves were subjected to social treatment when they were respectively 80 and 90 years old. Senior citizens were individually supported. However, social value was granted because the nation supervised it. As Bokho and Sijeong were assigned according to position and official ranks and kinds of things were different, the social limit was clearly shown. Social order was put above the ideology called Jonno thought. However, Jonno acts by age and position did not stay at the individual level and the nation took care of the senior citizens who are the members of society in various ways based on Jonno thought. Society tried to take care of the senior citizens who had difficulties in their activities because of being in physical decline. The nation increased the existence value of the senior citizens by giving things(賜物) including chairs, rice, meat, and ice economically, exoneration(免罪), the reduction system, and wergild legally, and Noinjik called Gaja(加資) socially to them and changing them to the members of society. Yangnoyeon and Gaja held targeting people of every class by transcending position and official ranks make the point that the senior citizens who are more than 80 years old are subject to social jonno clear. That is, the senior citizens were subject to respect for the elderly as the persons who were socially respected transcending their position when they got to be 80 years old.