• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.317-320
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• 1997

In the water purification plant, chemicals are injected for quick purification of raw water. It is clear that the amount of chemicals intrinsically depends on the water quality such as turbidity, temperature, pH and alkalinity etc. However, the process of chemical reaction to improve water quality by the chemicals is not yet fully clarified nor quantified. The feedback signal in the process of coagulant dosage, which should be measured (through the sensor of the plant) to compute the appropriate amount of chemicals, is also not available. Most traditional methods focus on judging the conditions of purifying reaction and determine the amounts of chemicals through manual operation of field experts or jar-test results. This paper presents the method of deriving the optimum dosing rate of coagulant, PAC(Polymerized Aluminium Chloride) for coagulant dosing process in water purification system. A neural network model is developed for coagulant dosing and purifying process. The optimum coagulant dosing rate can be derived the neural network model. Conventionally, four input variables (turbidity, temperature, pH, alkalinity of raw water) are known to be related to the process, while considering the relationships to the reaction of coagulation and flocculation. Also, the turbidity in flocculator is regarded as a new input variable. And the genetic algorithm is utilized to identify the neural network structure. The ability of the proposed scheme validated through the field test is proved to be of considerable practical value.

• Structural Engineering and Mechanics
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• 제73권3호
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• pp.339-351
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• 2020

Earthquakes are natural disasters that cause serious social disruptions and economic losses. In particular, they have a significant impact on critical lifeline infrastructure such as urban water transmission networks. Therefore, it is important to predict network performance and provide an alternative that minimizes the damage by considering the factors affecting lifeline structures. This paper proposes a probabilistic reliability approach for post-hazard flow analysis of a water transmission network according to earthquake magnitude, pipeline deterioration, and interdependency between pumping plants and 154 kV substations. The model is composed of the following three phases: (1) generation of input ground motion considering spatial correlation, (2) updating the revised nodal demands, and (3) calculation of available nodal demands. Accordingly, a computer code was developed to perform the hydraulic analysis and numerical modelling of water facilities. For numerical simulation, an actual water transmission network was considered and the epicenter was determined from historical earthquake data. To evaluate the network performance, flow-based performance indicators such as system serviceability, nodal serviceability, and mean normal status rate were introduced. The results from the proposed approach quantitatively show that the water network is significantly affected by not only the magnitude of the earthquake but the interdependency and pipeline deterioration.

• 한국수자원학회논문집
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• 제39권8호
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• pp.645-658
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• 2006

수문학적인 가뭄평가를 위하여 SWSI 가뭄지수를 보완한 MSWSI 개발하였다. MSWSI의 적용을 위하여 가뭄에 영향을 미치는 수문인자가 동질한 지역 즉, 댐, 하천, 지하수, 강수 지역으로 전국을 32개의 지역으로 분할하였다. 각각의 지역에 MSWSI를 적용하여 공간적으로 준분포형의 수문학적 가뭄 정보를 획득하였으며, 시간적으로 1974년부터 2001년까지의 한달 간격으로 평가하였다. 과거 가뭄 사상 년도에 대하여 기상학적 가뭄지수인 PDSI와의 비교, 분석을 통하여 수문학적인 가뭄 평가 결과에 대하여 검증하였다.

• 한국환경보건학회지
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• 제27권1호
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• pp.44-50
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• 2001

This study was carried out to investigate characteristics of water quality and THMs formation in lake-waters at kunsan. Of the parameters examined for water quality, pH, alkalinity, SO$_4$$^{-2}$ and Co- reflected the characteristics according to the origin, geography and water source of lakes while COD, SS, T-P, T-N and chlorophyll-a corelatively reflected well the influence of pollution factors around factors around lakes. The result of water quality analysis showed that most lakes in Kunsan area have the severe eutropnication problem, especially in summer. In lake-waters, THMFP overally continued to increase until 48 hour with the reaction time and THMs formation was largely achieved within 24 hour of the reaction time. The average formation ratio were 68.2% for CHCl$_3$, 23.6% for CHCl$_2$Br, 7.6% for CHClBr$_3$ and 0.6% for CHBr$_3$respectively and much difference depending on the reaction time was not shown. Overally, 96h-THEFP levels in lakes were high during June~September and showed higher tencency in lakes where could be regarded more contaminated on the whole. These results suggest that THMFP may be available for the management of lake-water quality as one if the useful parameters for the general evaluation of contamination. 96h-THEMFP failed to show the strong corelation individually with pH, TOC, COD and chlorphyll-a.

• 한국유체기계학회 논문집
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• 제17권6호
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• pp.84-88
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• 2014

A long term passive cooling system is considered as the most important safety feature for the nuclear design after the Fukushima Daiichi nuclear power plant accident in 2011. The conventional active pump driven safety systems are not available during a station Black Out (SBO) accident. The current design requirement on cooling time of the Passive Auxiliarly Feedwater System (PAFS) is about 8 hours only. To meet the 72 hours cooling time, the pool capacity of cooling water tank should be increased as much as 3~4 times larger than that of current water cooling tank. In order to extend the cooling time for 72 hours, a new passive air-water combined cooling system is proposed. This paper provides the feasibility of the combined passive air-water cooling system. The current pool capacity of water cooling system is preserved, and the cooling capability is extended by an additional air cooler.

• 한국물환경학회지
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• 제22권6호
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• pp.1004-1013
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• 2006

To effective a watershed management, it is necessary to have one or more quantitative measures that can be used to evaluate the relationship between pollutant sources and their impact on water quality. Such measurable quantities are termed indicators. Once an indicator has been selected, a target value for that indicator must be established that seek to distinguish between the impaired and unimpaired state of the waterbody. Various factors will be considered for the selection of an appropriate watershed management indicator. For example, available data, application, management conditions, cost, etc. This paper lists various factors that should be addressed in choosing a watershed management indicators and investigates applicable indicators during watershed management period.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1996년도 International Conference on Agricultural Machinery Engineering Proceedings
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• pp.212-218
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• 1996

The concrete pipe used to distribute irrigation water to the right place now available is commonly made up of cement , sand, earth, pebble, etc. These materials with right ratio and right amount of water were mixed and squeezed through the pipe-making machine called vertical squeezed pipe-making machine, and then a cement prefabricated pipe is produced . This kinds of pipe has been expanding by leaps and bounds. Being little cement contents and low cost, the length of pipe is 1.0m or so with weight of 50kg, which is easy to be made and to be transported. The demolish pressure of it is 0.2 MPa or so, which meets the needs of agriculture irrigation . The buried pipe irrigation system, has been popularized in Jining Municipal , Shandong Province. By the year of 1995 , the irrigation area under pipe conveyancesystem usign this type of pipe has reached 74000 hectares. By calculation, about 27.7million ㎥ water, 2.88 million kWh power , 0.167 million man power and 1528 hectares cu tivated land will be saved one year, adding value of agriculture output increased by 10 million kg. The total economic benefits amount to 0.92 million US$ a year. The paper presents the pipe making course and its application on a large scale area.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.471-474
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• 2002

A fuel tank contains water at the bottom under the fuel. The water comes from humidity by temperature change of inside and outside of tank. So it is necessary to measure both level to check precise amount of oil. But measuring instrument for level of water and fuel is not available yet. Since the fuel is inflammable, the sensor system must not include any electric circuits in the fuel tank. Optical cable sensor can satisfy this non-explosive condition. The displacement of a float changing by water level makes bending curvature of optical cable different. As the float rise up, the optical cable is bent more and the light signal in the cable decreases. The reduction of light signal is detected and it is converted into the change of water level. The output signal from a photo diode shows the proportional relation of water level. The increase of sensor voltage as a unit of ㎷ follows the level position of the float that is located between water and gasoline in the tank.

• 한국환경과학회지
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• 제13권12호
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• pp.1041-1048
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• 2004

In this study the results of optimal water supply analysis by operating constraints of reservoirs during drought period are as follows. During drought period, water supply reliability is possible about $97\~61{\%}$ by CASE 1-CASE 5. Water supply reliability is possible about $97.3{\%}$ in case of the Andong dam and $87.7{\%}$ in case of the Imha dam by CASE 3. Also, under the constraints of CASE 4, water supply reliability is possible about $87.5{\%}$ in case of the Andong dam and $73.3{\%}$ in case of the Imha dam. The reason what low of available water supply ratio is decreased inflow of Imha dam. When compare standard deviation of average storage with standard deviation of storage, stable storage can be secured during successive drought period. And it also can minimize shortage of water during drought. therefore, it is impossible that reservoir supply sufficient water but change of operating condition is better than pervious on that followed by full reservoir level. It is need that the study for optimal water supply during drought period has to be continued.

• 적정기술학회지
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• 제5권1호
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• pp.8-17
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• 2019

Solar pumps, for water lift systems, is becoming popular in rural areas for supplying drinking water in dry seasons when its need is elevated. The development in technology has also made solar pumps readily available and cheap which has increased its demands. So, for scattered settlements having a limited budget for operation and maintenance costs, solar pump is preferred over grid connected electrical pumping systems. This primary objective of the study was to design a solar photovoltaic pumping drinking water supply system for a small health post which is about 45 km east from Kathmandu, the capital city of Nepal. The study also compared and verified the final design with the system's existing design prepared by a development agency. The water source for this study was a confined aquifer 115m below the surface. The water demand was calculated to be 11m³ per day. A 1500 kPa submersible pump attached to a motor was selected and installed. Along with that twelve solar panels, reservoir, transmission main and distribution main was designed. The outcomes conclude solar photovoltaic pumping water supply systems to be cost-effective with an estimated cost of only USD 0.84 million per MLD. Solar pumps require low maintenance and operation costs and its repairs can quickly be done by the local people. The study also shows that solar technology produces no sound, needs no fuel making it environmentally friendly.