• Ocean and Polar Research
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• 제25권1호
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• pp.1-7
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• 2003

The purpose of this study was to determine changes in the growth rates and the degree of shell bioerosion exhibited by endolithic organisms of the Japanese scallop family, Patinopecten (Mizuhopecten) yessoensis, on the coast of Furugelm Island (Peter the Great Bay, northwest of East Sea = Sea of Japan) over the last three decades. The areas studied are affected by lumen (Tumangang) River run-off, which is enriched by organic matter and polluting agents. It was found that the linear growth rates of the Japanese scallops living along the coasts of Furugelm Island have decreased over the last three decades. The degree of bioerosion of scallop shells has significantly increased for the same period. These phenomena may be explained by a gradual increase in bottom sediment silting, organic enrichment and pollution of the areas being studied. It was found that the degree of scallop shell bioerosion increased with the scallop's age. At present, In each age group, the shells of the scallops sampled from the muddy sand showed greater erosion than the shells of individuals collected from the sandy substrate.

• 한국지형학회지
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• 제15권2호
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• pp.37-53
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• 2008

본 연구는 장기적인 기상 자료(meterological data)와 하천 유출량 자료(stream run off data)의 획득이 가능한 충청도 병천천 유역에 대해 BROOK90 4.4e 물리 결정 물 수지 모델(physical deterministic water balance model)을 사용하여 '병천천 유역의 물 수지 모델'을 수립한 것이다. 모델 조작 매개변수(model fitting parameter)를 교정(calibration)한 비준 모델(validation model)을 가지고 기상 자료(meterological data)가 있지만 하천 유출량 자료(stream runoff data)는 없는 시기에 대한 장기적인 물 수지를 수립하였다. 연구의 결과는 a priori 모의 단계에서 실측 하천 유출량(measured stream runoff data)과 모의 하천 유출량(simulated stream runoff data)이 유사하게 나옴으로써 물 수지 모의 실험(experiment for water balance modeling)이라는 연구 성격으로서 목표하는 첫 번째 기대 수준에 도달하고 있다. 모델 조작 매개변수(model fitting parameter)를 확정하고 수행한 비준 모의(validated simulation)를 통해 과거 9년(1998년 ~ 2006년)의 물 수지가 복원되었다. 이 유역의 지형(geomophology), 식생(vegetation), 토양(soil), 토지이용(land use) 상황이 변하지 않는다면 기상자료(meterological data)만 가지고서 언제나 하천 유출량(stream runoff amount), 토양수량(siol water amount) 그리고 증발산량(evapotranspiration) 등 다양한 수문기후 자료를 생산할 수 있다. 이 연구는 현재 한국의 물 수지(water balance) 수립은 물론이고 과거의 물 수지 복원(water balance reconstruction) 분야에 또 하나 새로운 지평을 열었다. 이러한 연구 결과는 한반도에서의 기후(climate)와 식생(vegetation)의 변화에 따른 미래 물 수지(water balance) 예측 분야에서도 널리 활용할 수 있을 것이다.

• 한국수자원학회논문집
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• 제39권11호
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• pp.905-914
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• 2006

유역의 정확한 강우-유출관계를 모의하기 위해서는 모형의 적용과 더불어 관측자료의 정확한 평가 및 검증이 병행되어야 한다. 본 연구에서는 SSARR모형을 금강유역에 적용하여 모의결과를 주요제어지점인 공주지점의 유량과 비교하였다. 분석결과 이수기시 저수위 구간에서 상당한 오차가 발생하였으며, 이에 대한 원인 분석을 위해 과거 관측유량자료(Rating Curve)의 신뢰도분석 및 유량 재관측($'03{\sim}'05$년)을 실시하였고, 유출성분 분석기법을 활용한 장기유출량을 산정하여 제어지점의 수리특성을 명확히 분석하고자 하였다. 분석결과 SSARR 모의결과 및 유출성분분석에 의한 장기유출량 산정결과는 재관측된 유량과 근사한 것으로 분석되었으나, 기존의 관측유량은 지점의 공간적 특성에 기인한 수리학적 영향으로 인해 평 갈수기시 약 $10{\sim}20%$ 과대 산정된 것으로 분석되어 이에 관한 보정 및 지속적인 모니터링이 필요하다.

• 한국농공학회지
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• 제29권4호
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• pp.59-72
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• 1987

Although long-term runoff analysis is important as much as flood analysis in the design of water works, the technological level of the former is relatively lower than that of the latter. In this respect, the precise estimation model for the volume of successive runoff should he developed as soon as possible. Up to now, in Korea, Gajiyama's formula has been widely used in long-term runoff analysis, which has many problems in applying in real situation. On the other hand, in flood analysis, unit hydrograph method has been exclusively used. Therefore, this study aims at trying to apply unit hydrograph method in long-term runoff analysis for the betterment of its estimation. Four test catchment areas were selected ; Maesan area in Namlum river as a representative area of Han river system, Cheongju area in Musim river as one of Geum river system, Hwasun area in Hwasun river as one of Yongsan river system, and Supyung area in Geum river as one of Nakdong river system. In the analysis of unit hydrograph, seperation of effective rainfall was carried out firstly. Considering that effective rainfall and moisture condition of catchrnent area are inside and outside of a phenomenon respectively and the latter is not considered in the analysis, Initial base flow(qb)was selected as an index of moisture condition. At the same time, basic equation(Eq.7) was established, in which qb can take a role as a parameter in relating between cumulative rainfall(P) and cumulative loss of rainfall(Ld). Based on the above equation, computer program for estimation model of qbwas seperately developed according to the range of qb, Developed model was applied to measured hydrographs and hyetographs for total 10 years in 4 test areas and effective rainfall was estimated. Estimation precision of model was checked as shown in Tab- 6 and Fig.8. In the next stage, based on the estimated effective rainfall(R) and runoff(Qd), a runoff distribution ratio was calculated for each teat area using by computerised least square method and used in making unit hydrographs in each test area. Significance of induced hydrographs was tested by checking the relative errors between estimated and measured runoff volume(Tab-9, 10). According to the results, runoff estimation error by unit hydrograph itself was merely 2 or 3 %, but other 2 or 3 % of error proved to be transferred error in the seperation of effective rainfall. In this study, special attentioning point is that, in spite of different river systems and forest conditions of test areas, standardized unit hydrographs for them have very similar curve shape, which can be explained by having similar catchinent characteristics such as stream length, catchinent area, slope, and vegetation intensity. That fact should be treated as important factor ingeneralization of unit hydrograph method.

• Ocean Science Journal
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• 제41권4호
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• pp.211-219
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• 2006

A comparison was made of population of the economically important cockle Anadara (=Scapharca) broughtoni (Bivalvia, Arcidae) inhabiting different areas of the Razdolnaya River estuary at the head of Amurskii Bay (Peter the Great Gulf, East Sea). Also, changes in cockle population density and structure, as well as in cockle growth rates during the last 20 years were studied. In all years of investigation, the morphometrical parameters and growth rates of cockles were smaller at the sites located close to the River mouth than farther down-estuary. The differences can be attributed to higher concentration of suspended particulate matter, decreased salinity and water temperature, as well as a longer exposure to these unfavorable environmental factors at sites located close to the River mouth, compared to farther sites. For two decades, cockle population density had decreased by almost 30 times at some sites in the River estuary. The main reason for this population decline is commercial over-fishing of the cockle. Besides, for the last 20 years, linear parameters of the cockles in the population decreased approximately by 30% and weight parameters, almost two times. Cockle growth rates also decreased for this period. Evidently, these facts are due to the damaging effect of dredging.

• 한국농공학회논문집
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• 제59권4호
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• pp.85-96
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• 2017

In this research, I performed rainfall monitoring by selecting the spot which can represent high altitude cool farm region in recent 3 years, and tried to understand the characteristic of outflow of non-point pollutants coming from high altitude cool farm region. As a result, it was shown that reducing rainfall runoff in highland farm area can reduce non-point pollution load and should consider priority to reduce runoff through management resources when selecting abatement method. Additionally, it is judged that reduction method related to base run-off should be selected by performing research on material motion of TN.

• 한국농공학회논문집
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• 제48권1호
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• pp.27-38
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• 2006

In this study, we developed a program to estimate discharge efficiently considering major hydraulic characteristic including water level, river bed, water slope and roughness coefficient in a natural river. Stream discharge was measured at Gongju gauge station located in the down stream of the Daechung Dam during normal and dry seasons from 2003 to 2004. The developed model was compared with the results from the existing rating curve at T/M gage stations, and was used for runoff analyses. Evaluating the developed river discharge estimation program, it was applied during 1983-2004 that base flow separation method and RRFS (Rainfall Runoff Forecasting System) which is based on SSARR (Streamflow Synthesis And Resevoir Regulation). The result presents the stage-discharge curve creator range at the Gong-ju is overestimated by approximately $10-20\%$, especially at the low stage. It is attributed to the hydraulic characteristics at the study. The discharge simulated by the RRFS and base flow separation, which is calibrated using the measurement at the early spring and late fall season during relatively d]v season, shows the least errors. The coefficient of roughness at Gongju station varied with the high and low water level.

• 산업공학
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• 제20권2호
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• pp.186-194
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• 2007

Recent deregulation of Korean electricity industry has made each power generation company pay more attention to maximizing its own profit instead of minimizing the overall system operation cost while guaranteeing system security. Electricity power generation problem is typically defined as the problem of determining both the on and off status and the power generation level of each generator under the given fuel constraints, which has been known as Profit-Based Unit Commitment (PBUC) problem. To solve the PBUC problem, the previous research mostly focused on devising Lagrangian Relaxation (LR) based heuristic algorithms due to the complexity of the problem and the nonlinearity of constraints and objectives. However, these heuristic approaches have been reported as less practical in real world applications since the computational run time is usually quite high and it may take a while to implement the devised heuristic algorithms as software applications. Especially when considering long-term planning problem which spans at least one year, the complexity becomes higher. Therefore, this paper proposes an explicit column generation algorithm using power generation patterns and the proposed algorithm is successfully applied to a Korean power generation company. The proposed scheme has a robust structure so that it is expected to extend general PBUC problems.

• 한국추진공학회지
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• 제22권2호
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• pp.59-65
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• 2018

AP(Ammonium Perchlorate, $NH_4ClO_4$)를 포함하는 복합화약조성의 등온가열시험시, 일정 순도 이하의 AP를 사용하는 경우 "bulged"현상으로 인해 등온가열시험 결과를 얻을 수 없었다. 본 연구는 품질 혹은 순도에 따른 AP의 열적 안정성 차이에 대해 규명하기 위해 LOT 별 AP에 대해 DSC 결과를 분석하고, 그 분석결과를 등온가열시험 결과 및 ARC결과와 비교분석하였다. 또한 순도가 낮은 AP에 대해서는 재결정을 통해 포함된 불순물을 제거한 후 분석한 결과, 열적 안정성이 높아졌음을 확인하였다. DSC 고압팬을 사용하여 AP 순도를 결정하는 정량적 분석방법을 확립하였다.

• 한국농공학회논문집
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• 제62권4호
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• pp.1-12
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• 2020

The extreme 2017 spring drought affected a large portion of South Korea in the Southern Gyeonggi-do and Chungcheongnam-do districts. This drought event was one of the climatologically driest spring seasons over the 1961-2016 period of record. It was characterized by exceptionally low reservoir water levels, with the average water level being 36% lower over most of western South Korea. In this study, we consider drought response methods to alleviate the shortage of agricultural water in times of drought. It could be to store water from a stream into a reservoir. There is a cyclical method for reusing water supplied from a reservoir into streams through drainage. We intended to present a decision-making plan for water supply based on the calculation of the quantity of water supply and leakage. We compared the rainfall-runoff equation with the TANK model, which is a long-term run-off model. Estimations of reservoir inflow during non-irrigation seasons applied to the Madun, Daesa, and Pungjeon reservoirs. We applied the run-off flow to the last 30 years of rainfall data to estimate reservoir storage. We calculated the available water in the river during the non-irrigation season. The daily average inflow from 2003 to 2018 was calculated from October to April. Simulation results show that an average of 67,000 tons of water is obtained during the non-irrigation season. The report shows that about 53,000 tons of water are available except during the winter season from December to February. The Madun Reservoir began in early October with a 10 percent storage rate. In the starting ratio, a simulated rate of 4 K, 6 K, and 8 K tons is predicted to be 44%, 50%, and 60%. We can estimate the amount of water needed and the timing of water pump operations during the non-irrigation season that focuses on fresh water reservoirs and improve decision making for efficient water supplies.