• Journal of Korea Water Resources Association
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• v.31 no.6
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• pp.657-665
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• 1998

New diagnosing method o flood possibility was proposed. The method can be processed by following steps: first, decide if current available water resources are above normal or not; second, compute a consecutive period above normal; third, precipitation is accumulate through the period; fourth, daily depletion (runoff and evapotranspiration) amount is subtracted from the accumulated precipitation and remains are translated to one day's precipitation, which is called effective precipitation; and finally, effective precipitation index. the larger effective precipitation index means the higher flood possibility. This method has been applied to the flood event occurred in the central region of Korea at late July 1996 and compared with the study by Korea Water resources Association (1996). The new method is proven to be much faster in computation, and therefore much better in practical use for emergency situation than current rainfall-runoff models. It is because the new method simplifies some steps of currently used method such as parameter estimation and water level observation. It is also known that new method is more scientific than any other methods that use accumulated precipitation only as it considers the runoff depletion in time

• Journal of the Korean GEO-environmental Society
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• v.12 no.5
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• pp.5-12
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• 2011

Water content is one of the significant engineering properties of soil for predicting the behavior of soil matrix. Conventional drying oven can be widely used to obtain the values by drying the soil specimens for 16 to 24 hours at $105^{\circ}C$. Although a number of experimental data has been accumulated for the conventional method of drying soil for water contents, shortcomings of the method are still hard to overcome such as long drying time for in situ use and the difficulty of taking prompt actions against emergency cases. Recently, ASTM and JGS have established microwave oven drying techniques for obtaining water contents to cope with those problems. And the reliability evaluation study has been also performed on the microwave oven drying for water contents. Feasibility study of the microwave oven drying was performed to confirm the process of the technique with Jumunjin sand, kaolinite, bentonite, weathered granite soil, and organic soil. Investigation was also conducted on the factors affecting and enhancing the reliability of the technique.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.145-145
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• 2022

Availability of abundant water resources data in developing countries is a great concern that has hindered the adoption of deep learning techniques (DL) for disaster prevention and mitigation. On the contrary, over the last two decades, a sizeable amount of DL publication in disaster management emanated from developed countries with efficient data management systems. To understand the current state of DL adoption for solving water-related disaster management in developing countries, an extensive bibliometric review coupled with a theory-based analysis of related research documents is conducted from 2003 - 2022 using Web of Science, Scopus, VOSviewer software and PRISMA model. Results show that four major disasters - pluvial / fluvial flooding, land subsidence, drought and snow avalanche are the most prevalent. Also, recurrent flash floods and landslides caused by irregular rainfall pattern, abundant freshwater and mountainous terrains made India the only developing country with an impressive DL adoption rate of 50% publication count, thereby setting the pace for other developing countries. Further analysis indicates that economically-disadvantaged countries will experience a delay in DL implementation based on their Human Development Index (HDI) because DL implementation is capital-intensive. COVID-19 among other factors is identified as a driver of DL. Although, the Long Short Term Model (LSTM) model is the most frequently used, but optimal model performance is not limited to a certain model. Each DL model performs based on defined modelling objectives. Furthermore, effect of input data size shows no clear relationship with model performance while final model deployment in solving disaster problems in real-life scenarios is lacking. Therefore, data augmentation and transfer learning are recommended to solve data management problems. Intensive research, training, innovation, deployment using cheap web-based servers, APIs and nature-based solutions are encouraged to enhance disaster preparedness.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.2B
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• pp.173-179
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• 2009

Industrial water supplied by water resource project is essential input materials along with labor, capital and land for companies. It is very important to stably secure these input materials in order for the industry to generate additional values. If the supply of industrial water is stopped, it is known damage for the industry is greater than domestic water or agriculture water based on same amount of supply. Like this, the actual value of industrial water has been highly acknowledged from the intuitive perspective, but study on the value and benefits of industrial water has been rarely conducted. Therefore, this study verified the value of industrial water supplied from water resource project, and used marginal production value as a measure to estimate the benefits of industrial water in the analysis of economic efficiency. As a result of empirical analysis using Cobb-Douglas production function and Translog production function, industries' average marginal production value was $5,427KRW/m^3$ and $5,583KRW/m^3$ respectively. The marginal production value for eleven industries were estimated by using same method. The marginal production value by industries presented by this study will be used as important data to calculate benefits of industrial water in the future. Moreover, the result of this study will provide reasonable criteria for decision making on the allocation of water in emergency situation, and problem of resource supply from water resource project.

• Journal of Korea Water Resources Association
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• v.55 no.8
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• pp.565-575
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• 2022

Recently, in the field of water resource engineering, interest in predicting time series water levels and flow rates using deep learning technology that has rapidly developed along with the Fourth Industrial Revolution is increasing. In addition, although water-level and flow-rate prediction have been performed using the Long Short-Term Memory (LSTM) model and Gated Recurrent Unit (GRU) model that can predict time-series data, the accuracy of flow-rate prediction in rivers with rapid temporal fluctuations was predicted to be very low compared to that of water-level prediction. In this study, the Paldang Bridge Station of the Han River, which has a large flow-rate fluctuation and little influence from tidal waves in the estuary, was selected. In addition, time-series data with large flow fluctuations were selected to collect water-level and flow-rate data for 2 years and 7 months, which are relatively short in data length, to be used as training and prediction data for the LSTM and GRU models. When learning time-series water levels with very high time fluctuation in two models, the predicted water-level results in both models secured appropriate accuracy compared to observation water levels, but when training rapidly temporal fluctuation flow rates directly in two models, the predicted flow rates deteriorated significantly. Therefore, in this study, in order to accurately predict the rapidly changing flow rate, the water-level data predicted by the two models could be used as input data for the rating curve to significantly improve the prediction accuracy of the flow rates. Finally, the results of this study are expected to be sufficiently used as the data of flood warning system in urban rivers where the observation length of hydrological data is not relatively long and the flow-rate changes rapidly.

• Journal of the Korean Society of Systems Engineering
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• v.12 no.2
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• pp.91-99
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• 2016

The safety of nuclear power plants has received much attention; this safety largely depends on the continuous availability of electrical energy source during all modes of nuclear power plant operation. A station blackout (SBO) describes the loss of the off-site electric power, the failure of the emergency diesel generators, and the unavailability of the alternate AC (AAC) power. Consequently, all systems that are AC powered such as the safety injection, shutdown cooling, component cooling water, and essential service water systems are unavailable. The aim of this study is to investigate the deficiencies of the existing alternatives for coping with an extended SBO for APR1400 design. The method is analyzing the existing deficiencies and proposing an optimal solution for the NPP design during the extended SBO. This study, established a new passive system, called passive decay heat removal system (PDHRS), using systems engineering approach.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.1765-1769
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• 2008

'96년, '98년 임진강 유역과 경기북부 지역 집중호우를 시작으로 '02년 태풍 "루사", '03년 "매미", '04년 "메기" 등의 영향으로 대규모 수공 구조물의 설계빈도를 초과하는 폭우를 동반하여 전국적으로 사상 유례없는 막대한 홍수피해를 발생시켰다. 이러한 과정에서 "연천댐", "장현, 동막저수지" 붕괴 등 댐 붕괴로 인하여 댐 하류지역의 홍수피해가 크게 발생하여 이에 대한 대처계획 수립 필요성 및 이를 위한 댐 붕괴로 인한 홍수류 해석에 대한 연구가 절실히 필요하다. 본 연구에서는 비상대처계획(Emergency Action Plan, EAP)수립 대상 국가시설물 중 하나인 양양양수발전소 하부댐에 대한 댐 붕괴 해석을 실시하였다. DAMBRK를 통하여 댐 지점의 붕괴유출수문곡선을 산정하였으며, 댐 하류하천 수위분석은 1차원 DAMBRK와 HEC-RAS모형을 이용비교 분석하였고 이를 통하여 댐붕괴로 인한 하류하천 홍수류 해석시 HEC-RAS모형의 적용성을 검토하였다. 검토결과 HEC-RAS모형 계산치가 DAMBRK 모형에 의한 결과 보다 과대하게 산정 되었다. 향후 댐 붕괴로 인한 홍수류 해석을 위한 HEC-RAS모형 모의시 주변지형의 홍수터화 등의 기법을 첨가하여 홍수위 분석이 필요한 것으로 사료된다.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.1588-1595
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• 2005

In this study, the installation location of accelerometer and accelerograph for dam are investigated in the field to establish of emergency action against dam failure when earthquake occur and to guarantee the results of seismic stability of dams which are analysed with dynamic analysis method during 1999 to 2003 by KOWACO. By a comparative study concerning of domestic and foreign guidelines of seismic strong motion instrumentation for dams, "Guidelines of Seismic Strong-Motion Instrumentation Installation, Operation and Maintenance for Dams" is established to set up the standard of seismic strong-motion instrumentation for dam, are supervised by KOWACO There is some problems in taking a measure of stability of dams when earthquake event occur because the existing seismic strong motion instruments are operated independently. This make difficult to confirm the occurrence of seismic event. For that reason, in this study the plan of unified operation and maintenance system for strong-motion instrument for dams is designed. It will make possible real-time seismic monitoring, data transmission and receiving, giving warning for earthquake, and exchanging data with national seismic network.

• Nuclear Engineering and Technology
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• v.34 no.5
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• pp.421-432
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• 2002

As one of the advanced design features of the APR1400, direct vessel injection (DVI) system is being considered instead of conventional cold leg injection (CLI) system. It is known that the DVI system greatly enhances the reliability of the emergency core cooling (ECC) system. However, there is still a dispute on its performance in terms of water delivery to the reactor core during the reflood phase of a large-break loss-of-coolant accident (LOCA). Thus, experimental validation is under progress. In this paper, test results of direct ECC bypass performed in the steam-water test facility tailed MIDAS (Multi-dimensional Investigation in Downcomer Annulus Simulation) are presented. The test condition is determined, based on the preliminary analysis of TRAC code, by applying the ‘modified linear scaling method’with the l/4.93 length scale . From the tests, ECC direct bypass fraction, steam condensation rate and information on the flow distribution in the upper annulus downcomer region are obtained.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.3
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• pp.294-300
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• 1995

In aquaculture industrial field, an automatic management and control system is needed to cope with the difficulties such as expensive wage, ripe age of management worker and risk according to the unexpected change of environmental conditions in the aquarium. This paper introduces an automatic aquarium monitoring and control system. The system is developed using PC single board computer. A PC can be connected to multi-single hoard computers, and the communication between PC and single board computers is based on RS-422/485 interfacing method. The physical data of pH, DO, temperature and water level etc. are real-timely treated in the single board computer though individual transducers, transfered to the main monitoring PC through RS-422/485 communication, and those data are graphically shown on the PC monitor. Furthermore, the environmental circumstance can be monitored through the image processing system, and the emergency system can be operated under the condition of environmental incident such as electric power stoppage, DO deficiency, pump shut down and low level water etc.