• 한국환경과학회지
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• 제8권1호
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• pp.1-6
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• 1999

This study was carried out to evaluate off-shore water quality and to draw marine pollution map to Southern sea in Korea by bioassay using gametes and early development system of Asterias amurensis. From the bioassay, it was determined that the water qualites of Southern sea maintained the grade II, because development of A. amurensis were moderately inhibited. However, Sunchon, Kwangyang, and Jinhae Bay belonged to grade III, because development of A. amurensis were strongly inhibited. This could be due to the inflows of several river systems and poor water circulation. The water quality at Yosu island was the grade I, because A. amurensis were not inhibited in its early development.

• Geomechanics and Engineering
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• 제21권2호
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• pp.165-170
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• 2020

The groundwater during tunnel excavation not only affects the stability of the tunnel and constructability but also causes the subsidence of the upper ground due to the lowering of groundwater. Generally, the cutoff grouting is applied as a countermeasure to reduce the groundwater inflow during tunnel excavation, and the cutoff grouting is often applied in the range of plastic zone around the tunnel. However, grouting in the plastic zone is only appropriate for ground reinforcement purposes, and guidelines for the application range of cutoff grouting and the targeted permeability coefficient of the grouting zone are required. In this study, the relationship between groundwater inflow into tunnel and application range of cutoff grouting and permeability coefficient is proposed and compared with numerical analysis results. It was found that grouting with tunnel radius thickness is appropriate to reduce the groundwater inflows effectively. More than 90% reduction in groundwater inflow can be achieved when the annular area of the tunnel radius thickness is grouted with a permeability reduction ratio of 1/50~1/200.

• 물과 미래
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• 제23권3호
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• pp.373-384
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• 1990

홍수기중 저수지운영의 목적은 댐 하류의 피해를 경감시키고 홍수 말기의 용수보존도 고려하는데 있다. 본 논문은 모의 기법을 응용하여 시간별 실시간 저수지 운영 모형을 제시한다. 운영 방안은 여수로를 통한 최대방류량을 최소화 하는 방류량 계열을 구했으며 예측유입량의 불확실성도 고려하였다. 병렬 저수지의 경우에는 합류점에의 방류량계열을 최소화하도록 유도하였으며, 본고에서는 단일 및 병렬 저수지에 적용할 수 있는 모형의 이론과 절차를 제시한다.

• Journal of information and communication convergence engineering
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• 제9권4호
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• pp.375-378
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• 2011

This study is intended to realize an intelligent controller using fuzzy control algorithms in order to recycle energy by recycling the waste water heat discharged by waste water heat collection boilers. Using waste water inflow temperature changes and waste water inflow amount changes as parameters, we present characteristic curves of the number of compressors being operated at fixed speeds and the temperature of hot water being discharged. We propose an intelligent controller that determines the optimum number of compressors being operated at fixed speeds in real time by measuring changes in the temperature and amount of waste water inflows in order to minimize the number of compressors being operated at fixed speeds relative to the waste water load flowing into the waste water heat collection boiler.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2012년도 학술발표회
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• pp.221-221
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• 2012

The WRAP-SALT (Water Rights Analysis Package-SALT) simulation includes computation of end-of-month reservoir storage concentrations and mean monthly reservoir outflow concentrations for each month of the simulation. The model computes reservoir storage loads and concentrations based on load balance accounting algorithms and computes concentrations of water released and withdrawn from a reservoir as a function of the volume-weighted mean concentration of the water stored in the reservoir in the current month or previous months. A load budget accounting of the various component load inflows and outflows entering and leaving a reservoir is performed. A time history of storage concentrations computed for previous months is maintained for use in the lag procedure. This study presents computational methods for routing salinity through reservoirs for incorporation into WRAP-SALT simulation routines and methods for determining values for the parameters of the routing methods.

• Korean Journal of Hydrosciences
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• 제5권
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• pp.57-70
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• 1994

For the system benefit optimization by considering risk or reliability from a multiple reservoir system using the Monte Carlo Technique, Many stochastically generated inflow series have to be used for the system analysis. In this study, the stochastically generated inflow series for the multiple reservoir system operation are preprocessed according to the considering system objectives and operating time periods. Through this procedure, several representative inflow series which have discrate probability levels and operation horizons are selected among the thousands of generated inflows. Then a deterministic optimization technique is applied to the hydropower energy estimation from the Han River Reservoir System which considers five reservoirs in this study. It took much less computational requirements than using the original Morite Carlo Technique, even though estimated result was almost similar.

• 천문학회지
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• 제52권3호
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• pp.83-88
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• 2019

Using ALMA observations of the $^{13}CN$ and DCN lines in the massive star-forming region G33.92+0.11A, we investigate the CN/HCN abundance ratio, which serves as a tracer of photodissociation chemistry, over the whole observed region. Even considering the uncertainties in calculating the abundance ratio, we find high ratios (${\gg}1$) in large parts of the source, especially in the outer regions of star-forming clumps A1, A2, and A5. Regions with high CN/HCN ratios coincide with the inflows of accreted gas suggested by Liu et al. (2015). We conclude that we found strong evidence for interaction between the dense gas clumps and the accreted ambient gas which may have sequentially triggered the star formation in these clumps.

• KDI Journal of Economic Policy
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• 제42권4호
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• pp.59-90
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• 2020

U.S. monetary policy has been claimed to generate global spillover and to destabilize other small open economies. We analyze the effects of certain identified U.S. monetary shocks on gross capital flows in the Korean economy using the local projection method. Consistent with previous results on other small open economies, we initially confirm that U.S. interest rate hikes are dynamically correlated with foreign outflows and residents' inflows. That is, not only are they correlated with withdrawals by foreigners but they are also correlated with those by domestic (Korean) investors. The results are mostly driven by portfolio flows. Second, however, the marginal response to a U.S. monetary policy shock is, on average, subdued if we focus on the sample periods after the Global financial crisis of 2007-2008 (henceforth, global financial crisis). We conjecture a possible reason behind the change, an institutional change related to financial friction. If the degree of pledgeability of the value of net worth increases, the marginal responses by both investors would drop with a U.S. monetary policy shock, consistent with our findings.

• 분석과 대안
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• 제5권2호
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• pp.3-38
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• 2021

Does Foreign Direct Investment (FDI) exacerbate income inequality in South Korea? If so, does rising income inequality come for the sake of economic growth? This study explores the impact of FDI on income inequality and growth in South Korea. To this end, we collect data on FDI and income inequality/economic growth at both national and provincial levels and empirically test their relationships in South Korea. The empirical results confirm our expectation that FDI magnifies income inequality. Furthermore, we fail to find a positive relationship between FDI and economic growth, implying that income inequality as a consequence of FDI does not come for the sake of economic growth in Korea. Findings suggest that more systematic research and nuanced policy design is necessary to circumvent the mechanisms at play that link the surge of FDI inflows and the exponential expansion of economic inequality.

• KDI Journal of Economic Policy
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• 제44권3호
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• pp.27-48
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• 2022

This paper reconsiders the empirical evidence of the relationship between tax treaties and FDI using U.S. outbound FDI to 78 countries over the period of 2007-2018. Unlike previous studies, we explicitly consider differences in the tax environments of recipient economies, including their tax-haven status, transfer pricing rules, CFC rules and anti-avoidance regulations, in our estimations. Our results confirm the importance of controlling for country-specific tax environments, especially the tax-haven status and transfer pricing rules. We find that tax treaties positively contribute to FDI inflows in developing countries, while they have no statistically significant impacts on OECD countries. Recently signed tax treaties still foster FDI but less than older ones do. Finally, our results indicate, all other things being equal, that the weaker the transfer pricing regulations, the greater the amount of U.S. direct investment into a non-OECD economy.