• Journal of Korean Society on Water Environment
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• v.28 no.2
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• pp.202-212
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• 2012

Due to the deterioration of water supply network and the deficiency of raw water, the water utility of local governments have performed various projects to improve their revenue water ratio. However, it is very difficult to estimate the cost for maintaining the revenue water ratio at higher level after completing the project, because local governments have different conditions affecting the operating and maintenance cost of water supply network. The purpose of this study is to present a procedure to estimate the operating and maintenance cost required to maintain the target revenue water ratio of the water supply network. For this purpose, we estimated the cost used only for operation and maintenance of water supply network of 164 local governments with the aid of K-Mean Clustering Analysis and the data from 40 representative local governments. Then, the regression analysis was performed to find relationship between revenue water ratio and the operating and maintenance cost with two different data sets generated by two classification methods; the first method classifies the local governments by means of k-means clustering, and the other classifies the local governments according to the index standardized by the operating and maintenance cost per unit length of water mains per revenue water ratio. The results shows that the method based on the index standardized by the cost and revenue water ratio of each government produces more reliable results for finding regression equations between revenue water ratio and the operating and maintenance cost only for water supply network. The estimated regression equations for each group can be used to estimate the cost required to keep the target revenue water ratio of the local government.

• Journal of Korean Society of Water and Wastewater
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• v.31 no.1
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• pp.51-62
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• 2017

For the asset management of a water pipe network, it would be necessary to understand the extent of the maintenance cost required for the water pipe network for the future. This study would develop a method to draw the optimum cost required for the maintenance of the water pipe network in waterworks facilities to maintain the aim revenue water ratio and to achieve the target revenue water ratio, considering the water service providers' waterworks condition and revenue water ratio comprehensively. This study conducted a survey with 96 water service providers as of the early 2015 and developed models to estimate the optimum maintenance cost of the water pipe network, considering the characteristics of the water service providers. Since the correlation coefficient of all the developed models was higher than 0.95, it turned out that it had significant reliability, which was statistically significant. As a result of applying the developed models to the actual water service providers, it was drawn that increasing revenue water ratio to more than a certain level can reduce the maintenance cost of the water pipe network by a great deal. In other words, it is judged that it would be the most efficient to secure the reliability of waterworks management by increasing the short-term revenue water ratio to more than a certain level and gradually increase the revenue water ratio from the long-term perspective. It is expected that the proposed methodology proposed in this study and the results of the study will be used as a basic research for planning the maintenance of water pipe network or establishing a plan for waterworks facilities asset management.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.776-777
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• 2011

조속기는 수차발전기의 핵심을 담당하는 두뇌라고 말할 수 있으며, 전력계통의 부하(주파수)가 변할 경우 수차발전기의 회전속도를 정격으로 유지시켜 양질의 전기를 생산하도록 항시 조정되는 역할을 한다. 최근 조속기는 디지털화되어 최적제어 감시 및 보호기능을 수행하고 있으나 문제점도 하나둘씩 나타나고 있는 실정이다. 본 논문에서는 디지털 가버너의 Isolation Mode에 대한 설명과 사고사례를 통해 디지털가버너 운영 시 문제점을 분석, 검토하여 보완하고자 하였으며, 이를 통해 안정적으로 전력공급을 주요 목적으로 하였다.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.353-354
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• 2008

옥외 현장에 설치되어 있는 PANEL은 하절기에 내부 온도가 높아져 PANEL 내부에 설치되어 있는 제어장치의 정상 동작을 방해 할 수 있다. 실제로 하절기 오후 $2{\sim}3$시경 PANEL 내부의 온도는 약 $60{\sim}75^{\circ}C$ 정도의 고온을 유지한다. 근래에는 현장 PANEL 내부에 PLC 및 컨트롤러등 전자화된 제어 장치의 설치 비중이 증가하고 있고 대부분의 컨트롤러 사용 온도는 약 $0{\sim}55^{\circ}C$ 이므로 하절기 고온 상태에서 정상적인 동작을 기대하기는 어렵다. 본 논문에서는 옥외 자립형 PANEL의 냉각 장치를 개발하여 운영하고 그 효과를 분석, 검토함으로써 하절기 고온 상태에서도 안정적으로 설비가 정상 동작하기 위한 방안 제시를 주요 목적으로 한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2001.10a
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• pp.11-14
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• 2001

This paper is studied on waste water maintenance management system for Integrated computing environment. This computing environment consist of Waste-Water Maintenance Management and GIS(Geographic Information System). This system can be developed by constructing Database which is set of rules occurring while management work of waste water system is processed. This system will help person who has responsible for making decision. Objective of such computing environment is providing efficient working environment for waste water facility management. Especially we analyzed problems of existing waste water maintenance management. We carried out efficient management of water facility and it will provide solution for major decision making work with low cost using Waste-Water Maintenance Management System

• Proceedings of the Korea Water Resources Association Conference
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• 2005.09b
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• pp.1361-1362
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• 2005

• Journal of Korean Society on Water Environment
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• v.36 no.1
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• pp.29-35
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• 2020

To manage the non-point source pollution and restore the water circulation, many technologies including infiltration or reservoir systems were installed in the urban area. These facilities have many problems regarding maintenance as their operation period becomes lengthier. The purpose of this study was to estimate the optimal maintenance timing through a long-term load test on the infiltration trench as one of the low impact development techniques. An infiltration trench was installed in the demonstration test facility, and stormwater was manufactured by Manual on installation and operation of non-point pollution management facilities from the Ministry of Environment, Korea and entered into the infiltration trench. Particle size distribution (PSD), suspended solids (SS) removal efficiency, and infiltration rate change tests were performed on inflow and outflow water. In case of the PSD, the maximum particulate size in the outflow decreased from 64 ㎛ to 33 ㎛ as the operating duration elapsed. The SS removal efficiency improved from 97 % to 99 %. The infiltration rate changed from 0.113 L/sec to 0.015 L/sec during the operation duration. The maintenance timing was determined based on the stormwater runoff requirements with these changes in water quality and infiltration rate. The methodologies in this study could be used to estimate the timing of maintenance of other low impact development techniques.

• Water for future
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• v.24 no.1
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• pp.83-92
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• 1991

The purpose of this paper is to estimate river maintenance water of the main gauging stations in Geum river watershed. The estimation methods of river maintenance water are classified into two categories : views of supply and demand. The definition of river main-tenance water in this paper, is the maximum value between mean drought flow and environmental conserving flow. In order to estimate river maintenance water, the mean drought flow estimated at the upstream of the Daecheong Dam but the downstream of the Daecheong Dam estimated mean drought flow and water quality control flow use of QUAL2E Model. In result, a mean drought flow showed large value at the Gong ju and Gyu am station as the downstream of the Daecheong Dam. The river maintenance water is 33.82$m^3$/sec at the Gong ju station, 51.51$m^3$/sec at the Gyu am station. Therefore, an estimation of the river maintenance water in the Geum River watershed concluded suitability which is determined mean drought flow.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.10a
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• pp.195-198
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• 2001

This paper has studied and developed a tool for water and waste-water maintenance management with which builds a database of various construction information and makes easier the report writing and data searching. The maintenance management for water and waste and water is a method and system to control a water and waste-water scientifically and structurally, and is also a combination system that connects water and waste-water construction companies with the related department of government, or local government by using a database. It has also analyzed problems on controlling method of an existing water and waste water, and explained functions to improve fallouts of a conventional system and expected effects when using the improved program.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.12
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• pp.1051-1070
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• 2009