• Journal of the Korean Association of Geographic Information Studies
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• v.9 no.2
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• pp.11-19
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• 2006

Sewerage is the system that improves the quality of human life and prevents many disasters such as floods. However the investigators in Korea only have been concerned about the sewer system, so the sewage treatment plant stays in the basic level like mapping. For example, only one attribute can be recognized in the linear object. Because of this limitation, it makes difficult to manage the linear attribute regarding to the sewage pipe plan. And it is impossible to control a partial (point type, line type) attribute changes of the linear object. We will therefore present the applicable method for the attribute changes of the linear object like the sewage pipe plans. For this reason, this paper is designed on the basis of Dynamic Segmentation(DS). DS has the advantage of giving the attribute value to the exact place in the linear object. As a result of using DS, the variety environment changes around the sewage pipes are applied to the building sewerage data. This also makes it possible to get a precise estimation for the maximum dirty water amount.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.11 no.4
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• pp.14-21
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• 2015

Korean government plans to establish large-scale horticulture facility complexes using reclaimed land in order to improve the national competitiveness of agriculture at the government level. One of the most significant problems arising from the establishment of those large-scale horticulture facilities is that these facilities still largely depend on a fossil fuel and they require 24 h a day heating during the winter season in order to provide the necessary breeding conditions for greenhouse crops. These facilities show large energy consumption due to the use of coverings with large heat transmission coefficients such as vinyl and glass during heating in the winter season. This study investigated the applicability of waste heat from power plant for large-scale horticulture facilities by evaluating the waste heat water temperature, heat loss and energy saving performance as a function of distance between power plant and greenhouse. As a result, utilizing power plant waste heat can reduce the energy consumption by around 85% compared to the conventional gas boiler, regardless of the distance between power plant and greenhouse.

• Journal of Korea Water Resources Association
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• v.33 no.3
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• pp.289-298
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• 2000

In order to minimize the impact of water hammer In a pipeline, a determination of optimum position of hydraulic structures with best operation of pressure relief valve was explored at the Seobyun pumping station. Method of characteristics is used to simulate a surge impact originating from abrupt stop of pumping operation in a pipeline. Genetic algorithm shows a powerful capability in searching a global solution, especially for a nonlinear problem The application results suggests that the maximum positive pressure can be relaxed by decreasing the opening time of pressure relief valve, meanwhile the maximum negative pressure can be relaxed by increasing the opening time of pressure relief valve. This study shows that the integration of a genetic algorithm with a transient analysis technique such as method of characteristic can improve the design of hydraulic structure in a pipe network.

• Journal of Korea Water Resources Association
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• v.46 no.7
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• pp.745-754
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• 2013

The systematic analysis and evaluation of required energy in the processes of drinking water production and supply have attracted considerable interest considering the need to overcome electricity shortage and control greenhouse gas emissions. On the basis of a review of existing research results, a practical method is developed in this study for evaluating energy in water supply networks. The proposed method can be applied to real water supply systems. A model based on the proposed method is developed by combining the hydraulic analysis results that are obtained using the EPANET2 software with a mathematical energy model on the MATLAB platform. It is suggested that performance indicators can evaluate the inherent efficiency of water supply facilities as well as their operational efficiency depending on the pipeline layout, pipe condition, and leakage level. The developed model is validated by applying it to virtual and real water supply systems. It is expected that the management of electric power demand on the peak time of water supply and the planning of an energy-efficient water supply system can be effectively achieved by the optimal management of energy by the proposed method in this study.

• Journal of Korea Game Society
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• v.15 no.6
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• pp.171-182
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• 2015

Existing hydraulic terrain erosion simulations mainly focus on small scale terrain deformations. In this paper, we propose a simulation method combining hydraulic terrain erosion and thermal erosion, by which a natural large scale terrain of mountainous regions with river networks can be created. For water movement we use the pipe model of shallow water simulation, and for the easy formation of watercourse we use velocity dependent erosion, also we apply thermal erosion for the formation of V-form slopes in the vicinity of stream lines. As a result, we can obtain good natural shaped terrains for certain ranges of $K_c$(sediment capacity constant) and $K_v$(velocity dependent erosion strength) values. Also we present improved thermal erosion method, and suggest a way to avoid problems caused by large $K_c$value.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.453-453
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• 2023

상수관망의 수질사고와 이상상황 발생시 대응을 위해서는 급수구역에 설치되어 있는 자동수질측정기, 정밀여과장치, 재염소주입설비, 자동드레인 등의 계측·제어설비들 간의 유기적인 정보공유를 통한 제어를 필요로 한다. 스마트 상수관망 운영플랫폼은 이러한 인프라 시설의 운영방안을 고려하여 분산되어 있는 계측데이터를 통합감시 및 제어하는 시스템으로 개발되었다. 상수관망 운영플랫폼은 능동형 분석 제어기술을 도입하여, 스마트 상수관망 인프라 설비를 최적제어할 수 있도록 구현하였다. 통합운영 플랫폼은 PostgreSQL, PostGIS, GeoServer, OpenLayers 등의 기술을 활용하여 개발하였다. 플랫폼은 계측감시, 시설관리, 운영제어 등의 기능으로 구성되며, 상수도 업무지원을 위한 관망해석 및 네트워크 분석 기능을 지원한다. 본 시스템은 스마트 상수도 구축사업을 통해 구축한 유량·수질모니터링 장비와 수질관리를 위해 도입된 재염소, 자동드레인 설비의 운영상태를 실시간 조회하는 모니터링 프로그램과, 관망해석 프로그램 그리고 대상설비의 최적제어를 위한 운영관리 프로그램으로 구성되어 있다. 모니터링 프로그램은 현장에서 측정되고 있는 유량, 수압, 수질, 펌프운전 등의 상태를 실시간으로 감시하고 클라우드 데이터베이스에 저장·관리하는 기능을 수행한다. 관망해석 프로그램은 EPA_Net모형과 연계되어 관망수리·수질해석을 수행하는 부분으로 재염소설비의 염소 추가주입이나 자동드레인을 통한 배제시 나타나게되는 관의 수리·수질변화를 클라우드 컴퓨팅 환경에서 분석하고 결과를 가시화 하는 기능을 갖고 있다. 운영관리 프로그램은 재염소 주입이 필요할 경우 주입량의 산정하는 부분과 관망 파손이나 수질사고 발생시 최적 단수예상지역을 도출하는 기능을 보유하고 있다. 향후 스마트 상수관망의 능동형 수질관리를 추진하는 지자체에 도입하여 인프라운영관리 기술 확보 및 수질관리 능력 개선과 실시간 감시 및 위기 대응능력 향상에 기여할 것으로 기대된다.

• International Journal of Air-Conditioning and Refrigeration
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• v.14 no.4
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• pp.147-155
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• 2006

The drag reduction (DR) and heat transfer efficiency reduction (ER) of non-ionic surfactant were investigated as a function of fluid velocity, temperature, and surfactant concentration. An experimental apparatus consisting of two temperature controlled water storage tanks, pumps, test specimen pipe and the piping network, two flow meters, two pressure gauges, a heat exchanger, and data logging system was built. From the experimental results, it was concluded that existing alkyl ammonium surfactant (CTAC Cethyl Trimethyl Ammonium Chloride) had DR of $0.6{\sim}0.8$ at $1,000{\sim}2,000ppm$ concentration with fluid temperature ranging between $50{\sim}60^{\circ}C$. However, the DR was very low when the fluid temperature was $70{\sim}80^{\circ}C$. The new amine oxide and betaine surfactant(SAOB Stearyl Amine Oxide + Betaine) had lower DR at fluid temperatures ranging between $50{\sim}60^{\circ}C$ compared with CTAC. However, with fluid temperature ranging between $70{\sim}80^{\circ}C$ the DR was $0.6{\sim}0.8$ when the concentration level was $1,000{\sim}2,000ppm$.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.2
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• pp.133-141
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• 2007

The drag reduction (DR) and heat transfer efficiency reduction (HTER) of nonionic surfactant according to the fluid velocity, temperature and surfactant concentration were investigated experimentally. For this study, several kinds of new surfactant which contains amine-oxide and betaine were developed. And experimental apparatus equipped with two water storage tanks temperature controlled, pumps, testing pipe network, two flowmeters, two pressure gauges, heat exchanger, and data logging system was built. Results showed that existing alkyl ammonium surfactant (CTAC) had DR of $0.6{\sim}0.8$ for $1,000{\sim}2,000\;ppm$ in fluid temperature of $50{\sim}60^{\circ}C$ and had very low DR in fluid temperature over $70^{\circ}C$. And new amino oxide and betaine surfactant (SAOB) had lower DR in fluid temperature of $50{\sim}60^{\circ}C$ compared with CTAC but in fluid temperature of $70{\sim}80^{\circ}C$ DR was $0.6{\sim}0.8$ for 1$1,000{\sim}2,000\;ppm$.

• Journal of Energy Engineering
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• v.19 no.2
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• pp.116-120
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• 2010

Overall total length of hydraulic pipe to transport the hot water in the domestic district heating network is above 3,000 Km approximately. This long pipe network requires a lots of the transport pumping power by surface friction of fluid. In this study, the drag reduction(DR) of Amin Oxide $C_{18}$ as non-ionic surfactant according to the fluid velocity, temperature and surfactant concentration under the condition of above $80^{\circ}C$ fluid temperature were investigated experimentally. Results showed that new amin oxide $C_{18}$ surfactant had DR of maximum 30% in fluid temperature of $80^{\circ}C$ and had 15% DR in fluid temperature over $100^{\circ}$ under short time test condition. And amine oxide had 155 hours duration time to keep the DR characteristic in the fluid temperature of $80^{\circ}$ and 1000 ppm concentration. But duration time of DR was decreased when fluid temperature increased.

• Journal of Korea Water Resources Association
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• v.55 no.5
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• pp.345-356
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• 2022

A severe flooding occured at a small urban catchment in Daejeon-si South Korea on July 30, 2020 causing significant loss of property (inundated 78 vehicles and two apartments) and life (one casualty and 56 victims). In this study, a retrospective analysis of the inundation event was implemented using a physically-based urban flood model, H12 with high-resolution data. H12 is an integrated 1-dimensional sewer network and 2-dimensional surface flow model supported by hybrid parallel techniques to efficiently deal with high-resolution data. In addition, we evaluated the impact of the flooding barriers which were installed after the flood disaster. As a result, it was found that the inundation was affected by a combination of multiple components including the shape of the basin, the low terrain of the inundation area located in the downstream part of the basin, and lack of pipe capacity to drain discharge from the upstream during heavy rain. The impact of the flooding barriers was analyzed by modeling with and without barriers on the high-resolution terrain input data. It was evaluated that the flood barriers effectively lower the water depth in the apartment complex. This study demonstrates capability of high-resolution physically-based urban modeling to quantitatively assess the past inundation event and the impact of the reduction measures.