• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.5
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• pp.75-83
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• 2023

As part of a study to analyze the excessive camber occurring in prestressed concrete railway bridges, this paper presents a calculation method and analysis results for the creep coefficient which defines the increase in camber of a concrete structure over time. Using the creep coefficient formula of the design code, the coefficient is obtained by applying the climatic conditions (relative humidity and temperature) of 12 regions in Korea. The effects of differences in climatic conditions by region and starting time of load on the creep coefficient are analyzed. In order to properly calculate the creep, most of which occurs in the early stages of loading, a detailed analysis is performed by applying a time step analysis method to consider varying climate conditions through loaded period. The creep coefficient obtained by applying the average climate conditions of the region is similar to the average of the creep coefficients obtained by time step analysis. Through time step analysis, it is shown that the offset and overlap effects of relative humidity and temperature on the creep coefficient and the climate effect at the time of initial loading can be appropriately represented.

• Journal of Korea Port Economic Association
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• v.36 no.2
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• pp.87-108
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• 2020

The Korean logistics industry has grown with the development of domestic industries. The industry plays an important role in national and regional economic growth, and the government has continued policy efforts to foster the industry. This study analyzes the competitiveness of the regional logistics industry and its contribution to the regional economy. Location coefficients are used to analyze local specialization in each logistics industry. The value-added rate, GDP contribution, value-added induction coefficient, and net value-added income of regional logistics industries are analyzed using a regional input-output table. As a result, the logistics industry is found to have net value-added income and competitiveness in some regions, and there is no relationship between the location coefficient and the value-added contribution of the regional logistics industry. Seoul, Incheon, Gyeonggi, Busan, and Jeju have the competitiveness of each logistics industry. In addition, we identified the regions where the logistics infrastructure is well developed and those in which it needs to be supported. The regions where the logistics industry has developed require policies for making high value-added by logistics activity, and regions with insufficient growth need to support the development of the logistics industry by investing human resources and capital that can meet the local demand.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.12B
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• pp.1087-1098
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• 2006

This study is unlike common Input-Output Analysis in the point that both RAS and methods are applied to the dynamic Input-Output Model simultaneously. We have analyzed the propagation effects on the regional economy from the investment generated by u-City construction in Wha-sung and Dong-tan City. The main results of the study are as follows. The total induced effect on production according to u-City construction in Wha-sung and Dong-tan City is estimated about 2.9 times. On the other hand, u-City industry is appreciated as a industry which a forward linkage effect is very high while a backward linkage effect is not that high.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.298-298
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• 2021

본 연구에서는 국내 6개 지역 서울, 강릉, 대전, 광주, 부산, 제주의 30년 치 시강우 자료에 해석적 확률모형(Analytical Probabilistic Models) 방법을 적용하여 도시 홍수 저감을 목적으로 하는 저류시설 설계를 위한 유출량 예측 정도를 지역별로 비교하고자 하였다. 강우 사상 분포의 해석적 확률모형을 적용하기 위해 무강우 시간을 결정하여 독립 호우를 결정하는데, 자기상관계수와 변동계수를 활용한 무강우 지속시간의 산정(IETD, Interevent Time Definition) 방법을 사용하였다. 해석적 확률모형인 유출량의 확률밀도함수(PDF, Probability Density Function)를 유도하기 위해서 불투수 지역과 투수 지역의 영향을 고려하여 유출계수를 적용하는 강우-유출 관계를 가지고 유출량을 정의하였다. 강우량, 강우 지속시간, 무강우시간과 같은 강우특성은 1변수 지수함수의 PDF를 따른다고 가정하였다. 확률모형 방법의 적합성을 판단하기 위해 결정된 IETD에 따라 각 지역별로 실제 강우 사상을 해석적 모델과 연속모의실험인 SWWM(Storm Water Management Model)에 적용하여 불투수율에 따른 유출량을 산정하였다. 각 방식으로 얻은 유출량 결과는 모든 지역에서 매우 유사하게 나타났고 결론적으로 우리나라에서 도시 홍수 저감을 위한 저류시설의 계획과 설계에 확률모형 방법이 적용 가능하다는 것을 확인할 수 있었다.

• Journal of the Korean earth science society
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• v.23 no.6
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• pp.507-513
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• 2002

To delineate the relationship between dynamic elastic modulus and lithologies, suspension PS logging was applied to Yuseong granite, Paldang banded gneiss, and Sabuk sedimentary rock. P and S wave velocities were also measured for these lithologies. In addition, uniaxial strength and Poisson’s ratio were measured in a laboratory for Yuseong granite and Paldang banded gneiss. In laboratory measurements, P and S wave velocities in Paldang banded gneiss were higher than those in Yuseong granite whereas Poisson’s ratio in Paldang banded gneiss was lower than that in Yuseong granite. This implies that P and S wave velocities correlate reversely with Poisson’s ratio. The dynamic Young modulus obtained from suspension PS logging was high compared to the dynamic bulk modulus and the dynamic shear modulus.

• Korean Journal of Remote Sensing
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• v.34 no.6_1
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• pp.969-979
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• 2018

This paper presents reflection symmetry of polarimetric SAR over the Amazon rainforest in terms of correlation coefficients between the pairs of HH- and HV-pol and VV- and VH-pol data by ALOS PALSAR. The reflection symmetry is defined as a non-zero correlation between HH- and HV-pol and VV- and VH-pol over natural distributed targets, and is a fundamental assumption for cross-talk calibration coefficient computation and for three-component decomposition for polarimetric SAR data. The Amazon rainforest is especially one of the common global reference sites for the reflection symmetry. The correlation coefficients for the pairs of reflection symmetry obtained in this study range from 0.018 to 0.097. The results imply that there exists a non-negligible dependency between co-pol and cross-pol in the distributed natural targets, and consequently the non-zero correlation must be considered as a potential contribution to errors of spaceborne SAR polarimetry to some extent.

• Journal of the Korean Regional Science Association
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• v.32 no.3
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• pp.17-27
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• 2016

In order to solve the problem of how to estimate the residential segregation, the Spatial Concentration Index(SCI) and Location quotient(LQ) are able to be one of alternative methods, and a comprehensive analysis of the residential segregation phenomenon in the seoul metropolitan area is the aim of the study. The results of SCI show that residential concentration areas in low-rent are some Gyeonggi-do's downtown(Bucheon-si, Suwon-si) as well as rural and urban-rural complex outskirts of the metropolitan area. The results of changing of SCI from 2011 to 2014, downward changes appeared thirteen districts and upward changes appeared fourteen districts. Especially downward change district was Sosa-gu, Bucheon-si and upward change district was Yeongtong-gu, Suwon-si. In conclusion, that high rent level groups are more concentration on specific area than low rent level groups. By decreasing residential concentration districts in low-rent level group, 'diversity' districts have been increasing in seoul metropolitan but the phenomenon of residential concentration in high and low level group have been being intensified. These results could be confirmed by quantitative through LQ. Methodologically LQ would strengthen the explanatory power of SCI, and ongoing research of SCI in conjunction with other quantitative methods will need.

• Environmental and Resource Economics Review
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• v.33 no.1
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• pp.87-112
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• 2024

This study estimates the regional input-output table and GHG emissions in 2019 and then analyzes the economic effects of carbon taxes by region and industry in Korea. The GHG emission, emission coefficient, and emission induction coefficient are estimated to be higher in manufacturing-oriented metropolitan provinces. The GHG emission coefficient in the same industry varies from region to region, which might reflect the standard of product classification, characteristics of production technology, and the regional differences in input structure. If a carbon tax is imposed, production costs are expected to increase and demand and production will decrease, especially in the manufacturing industry, which emits more GFG. On the other hand, the impact of carbon taxes on each region is not expected to vary significantly from region to region, which might be due to the fact that those differences are mitigated by industry-related effects. Since the impact of carbon taxes is expected to spread to the entire region, close cooperation between local governments is necessary in the process of implementing carbon neutrality in the future.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.spc1
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• pp.94-98
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• 2005

This study was carried out to provide the geographic information based on the distribution of rice qualities and palatability in Gyeoungbuk province of Korea. The rice grain quality and environmental factors were analyzed using 513 sampling sites based on different five-agroclimtic regions of Gyeoungbuk province during three years from 2002 to 2004. In rice grain quality characteristics, the average palatability was low in South eastern coastal and Tabaek semi alpine regions as $67.6\~68.3$ and the coefficient of variation (CV) was relatively high as $6.2\~7.4\%$. The average head rice rates were low in South and Central eastern coastal regions as $87.3\~88.2\%$ and CV was high as $8.2\~8.3\%$. The average protein content was high in Central eastern coastal regions as $8.0\%$ and CV was high as $8.2\~8.3\%$. In case of palatability, the variation was differed clearly between high and low agroclimatic regions; it means that it is possible to divide the same agroclimatic region of high CV into two or three areas by CV of palatability. As the results of subdividing each existing agroclimatic regions based on the palatability, the variation of grain quality characteristics was become lower than that of existing five-agroclimatic regions. Therefore, the re-establishing of agroclimatic region based on rice grain quality was very important for precise cultivation for rice.

• Korean Journal of Agricultural and Forest Meteorology
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• v.21 no.4
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• pp.238-249
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• 2019

The evapotranspiration is estimated based on weather factors such as temperature, wind speed and humidity, and the Hargreaves equation is a simple equation for calculating evapotranspiration using temperature data. However, the Hargreaves equation tends to be underestimated in areas with wind speeds above 3 m s^-1 and overestimated in areas with high relative humidity. The study was conducted to determine Hargreaves equation coefficient in 82 regions in Korea by comparing evapotranspiration determined by modified Hargreaves equation and the Penman-Monteith equation for the time period of 2008~2018. The modified Hargreaves coefficients for 50 inland areas were estimated to be 0.00173~0.00232(average 0.00196), which is similar to or lower than the default value 0.0023. On the other hand, there are 32 coastal areas, and the modified coefficients ranged from 0.00185 to 0.00303(average 0.00234). The east coastal area was estimated to be similar to or higher than the default value, while the west and south coastal areas showed large deviations by area. As results of estimating the evapotranspiration by the modified Hargreaves coefficient, root mean square error(RMSE) is reduced from 0.634~1.394(average 0.857) to 0.466~1.328(average 0.701), and Nash-Sutcliffe Coefficient(NSC) increased from -0.159~0.837(average 0.647) to -0.053~0.910(average 0.755) compared with original Hargreaves equation. Therefore, we confirmed that the Hargreaves equation can be overestimated or underestimated compared to the Penman-Monteith equation, and expected that it will be able to calculate the high accuracy evapotranspiration using the modified Hargreaves equation. This study will contribute to water resources planning, irrigation schedule, and environmental management.