• Korea Real Estate Review
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• v.28 no.3
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• pp.79-94
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• 2018

This study analyzed the factors associated with residential mobility based on the data from the 11th to the 19th wave of the Korean Labor & Income Panel Study (KLIPS). After grouping low-income households within the first to the fourth income bracket into households that exhibited no income bracket change and those with income bracket changes during the research period, this study examined the effects of the income situation of each group on residential mobility. According to the results of the analysis, in the group of households that showed no low-income bracket change, significant effects were found only in the age of the head of the household, housing cost, and rental deposit (Jeonse) and monthly rental of the household. In the group of households that showed low-income bracket changes, findings were generally in line with those of the whole household, where total income and the number of full-time employees in the household were the same as those of the whole household, indicating that it would be necessary to improve the employment stability of low-income households. Based on the findings of this study, housing inequality is intensifying within low-income households, and, thus, housing policies, based on continuing surveys, must be implemented to enhance income opportunities and stabilize the housing needs of low-income households.

• The Journal of the Korea Contents Association
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• v.17 no.10
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• pp.598-615
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• 2017

This paper compares the sources of the changes in the production of manufacturing industry between Korea and Japan during year 2000 ~year 2011 by I-O SDA. The results show that the first source of the increase in the production of Manufacturing industry in Korea is export, while in Japan the technological change. However, the contribution of technological change is relatively small in Korea and moreover decreasing. Meanwhile, the domestic final demand is the second source of the increase in the production of Korean manufacturing industry, but it was the first source of the decrease in the production of Japanese counterpart. On the other hand, the decrease in import substitution for both the intermediate and domestic final goods is significantly contributed to the decrease in the production of both Korean and Japanese manufacturing industry. Conclusively, these results confirm that the growth of Korean manufacturing industry has heavily depended on export. Then, considering the current global economic environment that is rapidly becoming more uncertain as well as volatile, the results imply that the heavy export dependence may become a key hurdle for the solid sustained growth of Korean manufacturing industry, so that policy ensuring more evenly balanced growth contribution from all growth sources is necessary. In particular, policy to promote technological change and import substitution is required with greater weight.

• Korean Journal of Ecology and Environment
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• v.51 no.1
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• pp.29-39
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• 2018

Long-term variation of zooplankton community and species composition was studied from 2003 to 2014 in a deep reservoir, Lake Soyang, in monsoon climate region, Korea. In addition, we examined the correlation with environmental factors. Annual precipitation of watershed showed a large variation in the $705{\sim}1,779mm\;yr^{-1}$ and more than 70% of it was being concentrated from June to September. The water quality of Lake Soyang was shown a clearly seasonal variations and particularly turbid water flowing into the lake during rainy season was the most important environmental factors. Zooplankton community in Lake Soyang showed a significant difference before and after 2006. Zooplankton biomass has shown a large increase and also showed a change in the zooplankton community structure since 2006. The of zooplankton showed positive correlation with temperature and BOD, Chl. a, TP concentration. These results are considered that nutrient and organic matter contained in the turbid water influences the increase in zooplankton biomass and species composition. However, water quality was limited to account for the increase in biomass of zooplankton. For example, increase of small zooplankton density (rotifer; Keratella cochlearis, Polyarthra vulgaris) in spring which is dominated by diatoms (large size; Melosira, Synedra etc.) is considered as a bottom-up effect by the microbial loop. And increased density of crustaceans in autumn was considered a top-down effects by the relationship between predator and prey of microzooplankton and mesozooplankton. In other words the inflow of allochthonous organic matter during rainy season also affected to zooplankton food web in Lake Soyang. In conclusion, biomass, diversity and long-term variations of zooplankton in Lake Soyang were determined by physico-chemical factors but also it is considered that biological interactions is important.

• Proceedings of the KIPE Conference
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• 2009.11a
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• pp.126-129
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• 2009

두 대 이상의 전원이 부하를 분담하는 경우 전원간의 통신이 없다면 여러 가지의 오차요인으로 인하여 문제가 생길 수 있다. 그래서 기존의 발전기 시스템은 이런 문제를 해결하기 위하여 droop제어를 수행하고 있다. 이와 마찬가지로 분산전원의 용량이 커짐에 따라 2대 이상의 분산전원이 병렬운전하여 고립된 계통에서 부하를 분담해야하는 경우 이들 간 통신이 없다면 문제가 된다. 그러나 발전기와는 달리 분산전원은 저압선로에서 전력을 공급하기 때문에 선로의 임피던스 특성에 따른 유 무효전력의 변동에 대한 분석이 필요하다. 본 논문에서는 분산전원의 병렬운전 시의 오차요인 계산하고 선로에 임피던스에 따른 유 무효전력의 변동을 분석하여 이를 시뮬레이션을 통하여 확인하고 저압선로에서의 분산전원 droop제어 방법에 대해서 연구하였다.

• Journal of Satellite, Information and Communications
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• v.12 no.4
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• pp.106-109
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• 2017

저궤도 위성의 배터리는 일반적으로 임무 및 식 구간에서의 부족한 전력 공급을 위해서 사용 되며, 버스 전압에 연결되어 있는 경우 출력 필터의 일부 기능을 담당하게 된다. 따라서 배터리의 주요 설계 요인은 전력 요구 분석을 통해 에너지 균형조건을 맞추기 위한 설계가 일반적이고, 배터리를 이용한 출력 전력 필터의 역할은 설계의 요인에 포함 되지 않는다. 하지만, 배터리는 전력 공급의 역할이외에도, 출력 전류의 변동이 극심하거나, 주기적으로 일정한 출력 변동을 발생하는 로드 등에 대한 필터 역할로써도 사용이 가능하다. 출력 커패시터를 배터리로 대체 할 경우 inrush 전류의 감소 및 추가적인 보호회로의 설계의 불필요 등의 장점을 가지고 있다. 배터리를 위성의 전력 공급을 위한 목적으로 사용하는 경우에는 전력 요구 분석을 통한 설계가 타당하나, 출력 로드 변동에 따른 영향을 줄이기 위해 필터로써 배터리를 사용하는 경우에는 사이즈 및 임피던스에 대한 추가적인 분석이 요구 된다. 따라서 본 논문에서는 저궤도 위성에서의 출력 전력 필터로 배터리를 이용한 설계 방안 및 성능 분석을 수행 하였다.

• The Korean Journal of Applied Statistics
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• v.27 no.3
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• pp.387-396
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• 2014

The GDP gap (also called the output gap) is the difference between potential GDP and actual GDP. Potential GDP is the maximum sustainable output that is achieved when the resources (labor and capital) are used to capacity. Central banks pursuing price and employment stability consider the output gap as an informative variable for monetary policy since the output gap could be regarded as a proxy of demand-supply imbalances. In this paper, the GDP gap of Korea is decomposed following the filtering method in the previous research, and major factors that affect the variation of GDP gap are investigated based on the decomposed series. The analysis results by the Super Smoother algorithm used in Fox et al. (2003)and Fox and Zurlinden (2006) are found consistent with theory. Much of the variation of nominal GDP gap is explained by Total Factor Productivity(TFP) gap, which is the change of productivity due to recent technological innovation and environmental change. It is also found that variation of terms of trade significantly affects the GDP gap of Korea due to its high dependency on international trade; however, the effect of the domestic price is not negligible like other countries.

• Journal of Soil and Groundwater Environment
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• v.7 no.3
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• pp.45-59
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• 2002

This study is objected to demonstrate the spatial variability of the ground-water recharge by classifying the types of ground-water hydrographs and assessing the recharge ratio(the ratio of the rise of ground-water level to cumulative precipitation) of each type using the National Ground-water Monitoring network data. A total of 5 types were identified by factor analysis on the ground-water hydrographs nationwide. The recharge ratio of each type were estimated to be 6.5% (TYPE I), 4.1 % (TYPE II), 9.2%(TYPE III), 5.8 %(TYPE IV), 15.3 %(TYPE V) in the confidence level of 95.44% and 6% variation was estimated site by site even in the same type. The recharges of Han, Nakdong, Keum, Youngsan·Seomjin river basins were estimated as 10.0 %, 6.1 %, 8.3 %. and 6.6 % respectively. These results were consistent with the results of the existing baseflow method.

• Environmental and Resource Economics Review
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• v.31 no.3
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• pp.393-417
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• 2022

Using hourly SMP data from 2016 to 2020, this paper measures the weekly realized volatility and investigates the main force of its determinants. To this end, we extend the Bayesian variable selection by incorporating the regime-switching model which identifies important variables among a large number of predictors by regimes. We find that the increase in coal and nuclear generation, as well as solar power, reinforce the SMP volatility in both high volatility and low volatility regime. In contrast the increase in gas generation and gas price decrease SMP volatility when SMP volatility is high. These results suggest that the expansion of renewable energy according to 2050 Carbon Neutrality or energy transition policies increases SMP volatility but the increase in the gas generation or reduction of coal generation might offset its impact.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.1596-1600
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• 2006

자연적인 하천은 하도 상황의 변경, 유역 토지이용의 변화, 댐과 저수지, 하천 골재채취의 영향 등 여러가지 요인에 의해 하상변동이 발생하게 된다. 본 연구에서는 금강 대청댐 하류구간의 실측자료를 토대로 장기하상변동 모의를 하여 예측된 결과와 실측단면을 비교하였으며, 실측단면이 장기하상변동 모의결과보다 상당히 저하된 것으로 분석되었다. 또한 금강의 측량자료를 수집하여 비교분석한 결과 시간이 경과함에 따라 금강의 하상이 지속적으로 저하되는 것으로 나타났으며, 대청댐 하류의 하상고는 대청댐 상류보다 저하폭이 상당히 큰 것으로 나타났다. 원인분석 결과 대청댐 건설로 인한 유사차단으로 인하여 대청댐 하류의 하상고는 지속적으로 저하되는 것으로 판단되었으며, 주요원인으로 금강의 골재채취가 금강하류 하상변동에서 상당히 큰 영향을 미치는 것으로 분석되었다.

• KDI Journal of Economic Policy
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• v.19 no.4
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• pp.3-46
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• 1997

본 논문은 우리나라 저축률(貯蓄率)의 결정요인을 실증적으로 분석하는 데 목적을 두고 있다. 특히 본 논문은 생애주기가설/항상소득가설(生涯週期假說/恒常所得假說)에 바탕을 두고 거시(巨視)시계열자료와 미시(微視)횡단면자료를 모두 분석함으로써 개별경제주체의 저축행위와 경제전체의 저축간의 일관된 관계를 밝히려고 하였다. 표준적인 생애주기가설/항상소득가설에 의하면, 저축은 소득(所得)의 일시적 변동으로부터 소비(消費)를 독립시키려는 개별소비자의 합리적 선택의 결과이다. 따라서 개별소비자의 저축은 단기적으로는 소득이 일시적으로 높은 해(년(年))에, 그리고 보다 장기적으로는 일생동안 가장 높은 수준의 소득을 벌게 되는 장년기간중에 가장 크게 된다. 본 논문의 실증결과는 이러한 생애주기가설/항상소득가설의 예측이 실제자료와 대체로 일치함을 보여준다. 거시자료 분석결과에 의하면 우리나라 저축률의 연간변동은 소득성장률(所得成長率)과 인구연령구조(人口年齡構造)의 변동에 의해서 잘 설명되는 것으로 나타난다. 또한 미시자료 분석결과를 보더라도 소득이 일시적으로 높은 가계나 경제활동연령인구의 비중이 높은 가계일수록 더 많은 저축을 하는 것으로 나타난다. 따라서 생애주기가설/항상소득가설은 우리나라 저축률의 결정을 설명하는 데 매우 유용하다고 판단된다. 본 논문은 또한 소득성장률이나 연령구조 외에 이자율, 유동성 제약, 그리고 예비적 저축동기 등이 저축에 미치는 영향에 대해서도 살펴보았다. 실증결과에 의하면 실질이자율은 저축률을 다소 증대시키는 효과가 있으나, 기타 요인들의 효과는 유의하지 않은 것으로 나타났다.