• Journal of Korea Water Resources Association
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• v.35 no.3
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• pp.251-259
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• 2002

Flow characteristics occurring a side-weir overflow in rectangular channel is investigated in this study. A numerical model based on the two -dimensional shallow-water equations is employed to review the factors influencing on the side- weir overflow discharge and the change of flow depths and velocities. It is found that the discharge coefficient which has the most significant influence on the overflow is affected by geometric characteristics of a side-weir, Froude number of the main channel flow and the flow depth of the main channel at the starting point of a side-weir. And the discharge coefficient applicable to a practical design of a side-weir is proposed by deriving a relationship between Froude number of the main channel flow at the starting point of a side-weir and Froude number of the main channel flow.

• Journal of Environmental Impact Assessment
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• v.19 no.3
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• pp.315-321
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• 2010

ArcView and water network models have been integrated to develop the water network modeling system based upon GIS. To develop this system, pre, main, and post processing systems are required. GIS programming technique was adopted by using the ArcView's script language Avenue. The input data of models have been prepared by using the AutoCAD Map3D through the conversion of modeling input data to GIS data for A city. The modeling has been implemented by using EPANET, WaterCAD, InfoWorks. To develop the post processing system, the modeling results of the water network models have been analyzed by using GIS. During the application process of the developed system to B city with 300,000 population, main problems were found in the constructed GIS DB of that city. Thus, pilot study area of B city has been constructed, and pre-, main, and post-processing techniques were invented based upon GIS. Finally, the problems related to waterworks GIS projects in Korea were discussed and solutions were suggested.

• Journal of Korean Society on Water Environment
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• v.23 no.1
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• pp.161-168
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• 2007

The main aim of this work is focus on the Geum river water quality evaluation of pollution data obtained by monitoring measurement during the period 2001-2005. The complex data matrix 19 (entire monitoring stations)*13 (parameters), 60 (month)*13 (parameters) and 20 (season)*13 (parameters) were treated with different multivariate techniques such as factor analysis/principal component analysis (FA/PCA). FA/PCA identified two factor (19*13) classified pollutant Loading factor (BOD, COD, pH, Cond, T-N, T-P, $NH_3$-N, $NO_3$-N, $PO_4$-P, Chl-a), seasonal factor (water temp, SS) and three Factor (60*13, 20*13) classified pollutant Loading factor (BOD, COD, Cond, T-N, T-P, $NH_3$-N, $NO_3$-N, $PO_4$-P), seasonal factor (water temp, SS) and metabolic factor (Chl-a, pH). Loadings of pollutant factor is potent influence main factor in the Geum river which is explained by loadings of pollutant factor at whole sampling stations (71.16%), month (52.75%) and season (56.57%) of main water quality stations. Result of this study is that pollutant loading factor is affected at Gongju 1, 2, Buyeo 1, 2, Gangkyeong, Yeongi stations by entire stations and entire month (Gongju 1, Cheongwon stations), April, May, July and August (buyeo 1) by month. Also the pollutant Loading factor is season gives an influence in winter (Gongju 1, buyeo 1) from main sampling stations, but Cheongwon characteristic is non-seasonal influenced. This study presents necessity and usefulness of multivariate statistic techniques for evaluation and interpretation of large complex data set with a view to get better information data effective management of water sources.

• Journal of Korean Public Health Nursing
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• v.10 no.1
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• pp.31-38
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• 1996

Disinfection is a very important process in water plant on account of our surface water usage. Particularly. the rainfall of Korea is concentrated in summer time. it is almost carried away to ocean before our utilization as water resource. To overcome the unbalance of water resource, artificial dams and reservoirs are constructed. According to such storage of water to aggravate water pollution and make the increase of water cleaning chemicals. Chlorine, as a main traditional chemical for water treatment. is focused on account of THMS formation in recent days. In this paper. the data of a water plant located in Seoul is adopted as the foundation of water quality analysis and introduce the substitute chemicals to supplement the harmful formation. additionally. Conclusions are summarized as follows: 1. The water quality of water resource is the worst in summer time and the supply of cleaning chemical is inevitably increased on account of general bacteria increase. 2. Chlorine, as a main chemical for water cleaning, formed the cancer-causing organic THMS with water molecules. 3. One of substitute chemical. chlorine dioxids suppress the formation of THMS comparing with the case of chlorine only. Therefore. the continuous research of substitute chemicals should be activated. 4. As the supply of disinfected clean water concerned with the citizen sanitary, the cultivation of professionals and academic conference must be needed on the basis of nation

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.18-21
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• 2006

Though there are several definitions for the Northeast Asia, in this paper Northeast Asia is defined as the geographical sphere including five countries. Those five countries are China, the Democratic People's Republic of Korea, Japan, Mongolia and the Republic of Korea. For the announcement of regional preparatory process at the $4^{th}$ World Water Forum (4WWF), basic characteristics and main water-related issues were surveyed in the Northeast Asian countries. This paper is mainly composed of basic characteristics of each country, main water challenges, implemented strategies, successful experiences and local actions, etc. The five countries provided one's country report on the Government basis in 2004 to Korea Water Forum (KWF) as the coordinator of Northeast Asia for the 4WWF. KWF summarized the report of each country very briefly as follows.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.1464-1468
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• 2007

The restoration project of Cheonggyecheon was conducted to creates the refreshing water-friendly environment in the downtown Seoul. It already have passed almost 2 years after restoration. This project changed environment of Cheonggyecheon dramatically, so historic hydrological data became useless. There are not so many hydrological data to manage and control this newly restored urban stream. The main purpose of this study is collecting and analysing the hydrological data of Cheonggyecheon. At first, we analysed the mechanism of Cheonggyecheon discharge using the sewage design maps and some GIS data. We also monitored the water levels and discharges of 5 main points of Cheonggyecheon. Rating curves of these 5 points were derived. There were 249 blocks of water gates which were located at both sides of bank. We also monitored the behaviors of these water gates. Through the these monitorings, some equations were derived to give useful information to the manager of Cheonggyecheon.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.8
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• pp.843-849
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• 2009

The reliable operation of a swing check valve in the main feed water system of a power plant is most essential for successful shout-down process. A failure to close the valve at proper time often leads to the instability of the main feed water system, or even to an emergency stop of the power plant. In reality it is a very difficult task to monitor the behavior of a swing check valve. Furthermore it is impossible to see the motion of the valve. In this work two measurements were carried out simultaneously to determine the precise valve closure time. The dynamic pressure measurements were made at the inlet and outlet regions of the swing check valve. The transient vibration of the valve housing in the direction of water flow was also measured, which enabled the measurement of the transient vibration of the valve housing near valve closure. By comparing the results produced from these measurements the precise valve closure time could be determined. By carrying out order tracking technique using the dynamic pressure signals and pump rpm signal, the complicated dynamic problems inside the main feed water system can be more easily dealt with. This measurement scheme might be implemented in a power plant on a real-time basis without much difficulty. If this could be implemented, valuable information essential for shut-down operations can readily be passed on to the main control room. The feasibility of this implementation was demonstrated by this experimental work.

• Water for future
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• v.28 no.4
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• pp.215-222
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• 1995

The water retention function which has the hysteresis phenomena is required to analyze the Richards equation which is a governing equation of the unsaturated flow, and its hysteresis phenomena has influence upon the characteristics of the unsaturated flow. The accuracy of the published hysteresis models is compared by using experimental data of the water retention function. The apparatus to experiment the hysteresis phenomena on the soil is developed, and experimental data for the main wetting process and the main drying process of the water retention function are obtained. The parameters of the van Genuchten equation are calibrated by using experimentally obtained data. As a result of the comparison of the selected hysteresis models which simulate the main drying curve from the main wetting curve, the Model I-1(Mualem) overestimates and the Model II-1(Mualem) underestimates but the Model III-2(Park and Sonu) similarly estimates the experimental data of the main drying curve.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.12
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• pp.663-670
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• 2019

Corrective thermal performance analysis is required for power plants' turbine cycles to determine the performance status of the cycle and improve the economic operation of the power plant. We developed a sectional classification method for the main feed-water flow to make precise corrections for the performance analysis based on the Performance Test Code (PTC) of the American Society of Mechanical Engineers (ASME). The method was developed for the estimation of the turbine cycle performance in a classified section. The classification is based on feature identification of the correlation status of the main feed-water flow measurements. We also developed predictive algorithms for the corrected main feed-water through a Kernel Regression (KR) model for each classified feature area. The method was compared with estimation using an Artificial Neural Network (ANN). The feature classification and predictive model provided more practical and reliable methods for the corrective thermal performance analysis of a turbine cycle.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.9
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• pp.1103-1108
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• 2012

A main steam pipe system is a branch pipe that connects a boiler with a turbine. Water hammering analysis is very important for limiting the damage caused to pipe systems by operation conditions. Water hammering created by an unsteady flow in pipeline systems can cause excessive change in pressure, vibration, and noise. The main steam pipe structure should be designed to safely maintain the pressure pulsation and several vibrations under operation environments. This study evaluated the structural integrity of a main steam pipe during suspended and normal operation by using the ASME fatigue life methodology and finite element analysis. In the analysis, water hammering was used for transient analysis. The calculated alternating stress and fatigue stress were compared with the applicable limits of ASME fatigue life. All the evaluation results satisfied the requirements of the ASME fatigue life.