용수공급을 위한 댐 방류량 결정에서의 앙상블 유량 예측 효과 분석

김연주,김기주,김영오,Kim, Yeonju,Kim, Gi Joo,Kim, Young-Oh 한국수자원학회 2023 한국수자원학회논문집 Vol.56 No.12

2000년대 이후 우리나라에 도입된 앙상블 유량 예측은 수문 예측 현업에서 성과를 보였음에도 불구하고 수자원 시스템 관리에서는 적극적으로 활용되지 못하고 있다. 따라서 본 연구에서는 용수공급을 위한 수자원 관리 측면에서 앙상블 유량 예측의 효용성을 보이고자 댐 실무자들을 위한 간단한 가상 예제를 만들고, 이를 확장하며 실제 대한민국 다목적댐에 적용하였다. 가상 예제에서는 앙상블 유량 예측의 평균은 같지만 표준편차가 다를 때, 댐 운영 비용이 상이함을 확인하였다. 그리고 이를 대한민국 다목적댐에 적용하기 위해 동일한 평균을 가지지만 표준편차가 평균과 동일한 유형W와 표준편차가 평균의 10배인 유형 P를 가정하여 용량 대비 연유입량 비율에 따라 소양강댐(CIR = 1.345)과 충주댐(CIR = 0.563)에 표본 추계학적 동적계획법으로 최적방류량을 도출하였다. 그리고 도출된 최적방류량으로 2020년부 2022년까지 모의 운영을 진행하였다. 그 결과, 충주댐에서는 표준편차가 적은 유형W에서 상대적으로 공격적인 최적방류량이 도출되었고, 모의 운영 결과 또한 양호함을 보였다. 소양강댐에서도 최적방류량에서 충주댐과 같은 결과를 보였지만, 모의 운영에서는 유형W와 P의 차이가 없었다. 결과적으로 동일한 평균을 가지더라도 앙상블 유량 예측의 표준편차에 따라 다른 최적방류량과 모의 운영 결과가 도출되었고, 특히 용량 대비 연유입량이 작을수록 이러한 불확실성에 더욱 민감하게 반응함을 보였다. 본 내용을 바탕으로 현재 단일 대푯값만을 사용하여 댐 운영을 하는 수자원 관리에 개선을 기대한다. Since the 2000s, ensemble streamflow prediction (ESP) has been actively utilized in South Korea, primarily for hydrological forecasting purposes. Despite its notable success in hydrological forecasting, the original objective of enhancing water resources system management has been relatively overlooked. Consequently, this study aims to demonstrate the utility of ESP in water resources management by creating a simple hypothetical exercise for dam operators and applying it to actual multi-purpose dams in South Korea. The hypothetical exercise showed that even when the means of ESP are identical, different costs can result from varying standard deviations. Subsequently, using sampling stochastic dynamic programming (SSDP) and considering the capacity-inflow ratio (CIR), optimal release patterns were derived for Soyang Dam (CIR = 1.345) and Chungju Dam (CIR = 0.563) based on types W and P. For this analysis, Type W was defined with standard deviation equal to the mean inflow, and Type P with standard deviation ten times of the mean inflow. Simulated operations were conducted from 2020 to 2022 using the derived optimal releases. The results indicate that in the case of Dam Chungju, more aggressive optimal release patterns were derived under types with smaller standard deviations, and the simulated operations demonstrated satisfactory outcomes. Similarly, Soyang Dam exhibited similar results in terms of optimal release, but there was no significant difference in the simulation between types W and P due to its large CIR. Ultimately, this study highlights that even with the same mean values, the standard deviation of ESP impacts optimal release patterns and outcomes in simulation. Additionally, it underscores that systems with smaller CIRs are more sensitive to such uncertainties. Based on these findings, there is potential for improvements in South Korea's current operational practices, which rely solely on single representative values for water resources management.

Wearable 휴대 전원용 PEMFC 의 NaCl 이 포함된 가습 시 유로 패턴의 영향

김준형(J. H. Kim),김준수(J. S. Kim),송동근(D. K. Song),유호준(H. J. Yoo),이영조(Y. J. Lee),장계은(G. Jang),임성한(S. H. Rhim),조구영(G. Y. Cho) Korean Society for Precision Engineering 2021 한국정밀공학회 학술발표대회 논문집 Vol.2021 No.11월

연료전지는 전기화학반응을 통해 수소의 화학에너지로부터 전기를 발생시키는 고효율 신재생 에너지 변환 장치이다. 특히, 고분자 전해질 연료전지(Polymer Electrolyte Membrane Fuel Cells, PEMFCs)는 높은 전력밀도, 낮은 작동 온도, 빠른 시동 능력의 장점을 가지고 수송분야를 중심으로 휴대용 전원, Wearable 전자기기의 전원 등 다양한 분야에 적용되고 있다. 또한, PEMFC 는 온실가스 감축 목표를 달성하기 위해 선박 및 해운분야에서도 수요가 증가하고 있으며 해수환경에서의 PEMFC 성능에 관한 연구가 지속적으로 진행되고 있다. 일반적으로 해수환경에서의 공기는 0.2-20 μm 크기의 해양성 에어로졸로 구성되며, PEMFC 음극에 공급되는 NaCl 입자는 연료전지의 심각한 성능 저하를 일으킬 수 있는 것으로 알려졌다. 일반적으로 PEMFC 의 전기화학적 특성은 Flow Channel 의 Type 에 따라서 큰 영향을 받는다. 따라서 본 연구에서는 분리판의 Flow Channel Type 을 변화시키며 NaCl 수용액을 활용한 가습 시 PEMFC 성능 및 내구성을 분석하였다. 연료전지에 공급되는 공기를 10 wt% NaCl 수용액으로 가습하였고, 이를 PEMFC 음극에 공급하였다. 또한, 상용 5 cm² 의 활성화 면적을 가진 막전극접합체(Membrane and Electrode Assembly)와 다양한 Flow Channel Type 을 가진 분리판을 사용하여 단위 셀을 구성하고, NaCl 수용액을 이용한 가습상황에서 각 유로 패턴에 따른 PEMFC 의 전기화학적 특성을 평가하였다.

사회-수문학(Socio-hydrology) 혹은 수문사회학(Hydro-sociology): 인간과 물 순환과의 상호진화 연구

김연주,정은성,Kim, Yeon-Ju,Jeong, Eun-Seong 한국수자원학회 2015 물과 미래(한국수자원학회지) Vol.48 No.7

흡연과 위암 발생의 관련성에 관한 지역사회 기반의 코호트 연구

김연주,신애선,곽진,전재관,박수경,강대희,신해림,장성훈,유근영,Kim, Yeon-Ju,Shin, Ae-Sun,Gwack, Jin,Jun, Jae-Kwan,Park, Sue-Kyung,Kang, Dae-Hee,Shin, Hai-Rim,Chang, Soung-Hoon,Yoo, Keun-Young 대한예방의학회 2007 예방의학회지 Vol.40 No.6

Objectives : Gastric cancer is the most common incident cancer in Korea. Although Helicobacter pylori infection is the most important risk factor for the development of gastric cancer, cigarette smoking has also been suggested to play an important role in the development of gastric cancer. The objective of this study is to evaluate the relationship between cigarette smoking and gastric cancer risk in a Korean population. Methods : The study population consisted of 13,785 subjects who had been enrolled in the Korean Multi-Center Career Cohort between 1993 and 2002. As of December 2002, 139 incident gastric cancer cases were ascertained through the Korea Central Cancer Registry and the National Death Certificate Database. Relative risks (RR) and 95% confidence intervals (CI) for gastric cancer were estimated using Cox#s proportional hazard model adjusted for age, education, alcohol drinking status and history of gastritis or ulcer. Results : Significant dose-response relationships were observed between the duration of smoking and the risk of gastric cancer among the male subjects in comparison to non-smokers: men who smoked for 20-39 years had a 2.09-fold (95% CI 1.00-4.38) increase, and those who smoked for more than 40 years had a 3.13-fold (95% CI 1.59-6.17) increase in the risk of gastric cancer ($P_{trend}<0.01$). Conclusions : This study suggests that a longer duration of cigarette smoking may increase the risk of gastric cancer development in a dose-response manner in Korean men. The association between smoking and gastric cancer risk in women should be verified in future studies with a larger number of cases.

Tialite계 세라믹 안료의 합성 및 유약에서의 발색

김연주,이병하,Kim, Yeon-Ju,Lee, Byung-Ha 한국재료학회 2011 한국재료학회지 Vol.21 No.8

[ $Al_2TiO_5$ ]has a high refractive index and good solubility of the chromophore in the $Al_2TiO_5$ lattice, which allows this structure to be a good candidate for the development of new ceramic pigments. However, pure $Al_2TiO_5$ is well known to decompose on firing at $900{\sim}1100^{\circ}C$. However, this process can be inhibited by the incorporation of certain metal cations into its crystalline lattice. In this study, the synthesis of gray ceramic pigment was performed by doping cobalt on the $Al_2TiO_5$ crystal structure. The $Al_2TiO_5$ was synthesized using $Al_2O_3$ and $TiO_2$, and doped with $Co_3O_4$ as a chromophore material. In order to prevent the thermal decomposition during the cooling procedure, MgO was added to samples by 0.05 mole, 0.1 mole, and 0.15 mole as a stabilizer. The samples were fired at $1500^{\circ}C$ for 2 hours and cooled naturally. The crystal structure, solubility limit, and color of the synthesized pigment were analyzed using XRD, Raman spectroscopy, UV, and UV-vis. $Al_2O_3$ was available for the formation of $CoAl_2O_4$, which should also be considered in order to explain the small amount of this phase detected in the sample with the higher $Co^{2+}$ content (${\geq}$ 0.03 mole). It was found that the solubility limit of $Co^{2+}$ in the $Al_2TiO_5$ crystal was 0.02 mole% through an analysis of Raman spectroscopy. Through the addition of a pigment with 0.02 mole% of $Co^{2+}$ to lime-barium glaze, stabilized gray color pigments with 66.54, -2.35, and 4.68 as CIE-$L^*a^*b^*$ were synthesized.

수의역학과 소셜네트워크분석(Social Network Analysis: SNA)

김연주,문운경,윤하정,Kim, Yeon-Ju,Mun, Un-Gyeong,Yun, Ha-Jeong 대한수의사회 2013 대한수의사회지 Vol.49 No.4

레몬 오일을 이용한 갱년기 여성 우울증 감소에 관한 연구

김연주(Kim Yeon-Zu) 한국인체미용예술학회 2006 한국인체미용예술학회지 Vol.7 No.3

  The aim of this study is to find out if lemon oil affects the decrease in depression of women in climacteric. First, literatures on depression of women in climacteric were referred to. Second, the research object was 26 women in climacteric. They had lemon oil inhalation for three weeks. Then they were given a test, Symtom Check List-90 Revision standardized by Gwang-il Kim.<BR>  As a result, no significant change happened. However when interviewed, they said they felt good and refreshed after using lemon oil.

Human footprint를 고려하는 글로벌 수문 및 수자원 모형

김연주,이상현,Kim, Yeon-Ju,Lee, Sang-Hyeon 한국수자원학회 2018 물과 미래(한국수자원학회지) Vol.51 No.2

크롬을 사용한 Tialite계 안료

김연주,이병하,Kim, Yeon-Ju,Lee, Byung-Ha 한국재료학회 2011 한국재료학회지 Vol.21 No.9

The purpose of this study was to determine the optimal firing condition and composition for $Al_2TiO_5$ crystal, which is suitable for stable coloration in glazes at high temperatures, using $Cr_2O_3$ as chromophore for the synthesis of $Al_2TiO_5$ system pigments. $Al_2TiO_5$ has a high refractive index and good solubility of chromophore in the $Al_2TiO_5$ lattice, making this structure a good candidate for the development of new ceramic pigments. Pigments were synthesized by using $Al_2O_3$ and $TiO_2$ mainly. Various amounts of $Cr_2O_3$ such as 0.01, 0.02, 0.03, 0.04 and 0.05 mole were also added. Each compound was synthesized at $1300^{\circ}C$, $1400^{\circ}C$, and $1500^{\circ}C$ for 2 hours and cooled naturally. The crystal structure, solubility limit, and color of the synthesized pigments were analyzed by XRD, SEM, Raman spectroscopy, UV and UV-vis. The changes in color as the result of applying 6 wt% of the synthesized pigments to lime barium glaze were expressed as CIE-L*a*b* values. A $Cr_2O_3$ 0.03 mole doped $Al_2TiO_5$ brown pigment was successfully synthesize at $1400^{\circ}C$, and the values of CIE-L*a*b* parameters were L* = 44.62, a* = 3.10, and b* = 17.25. In the case of the pigment synthesized at $1500^{\circ}C$, the brown color was obtained at 0.01 mole and 0.02 mole $Cr_2O_3$, and the CIE-L*a*b* values were 55.34, 1.73, 28.64, and 49.39, 0.51, 21.33, respectively. At $1500^{\circ}C$, the maximum limit of solid solution was 0.03 mole $Cr_2O_3$. The glazed sample showed green color, and the values of the CIEL* a*b* parameters were L* = 45.69, a* = -0.98, and b* = 20.38.

기생충박멸은 국가안보와 직결된다

김연주,Kim, Yeon-Ju 한국건강관리협회 1975 건강소식 Vol.3 No.7