• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2019년도 학술발표회
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• pp.160-160
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• 2019

Water is a limited source that needs to be properly managed and distributed to the ever-growing population of the world. Rapid urbanization and development have increased the overall water demand of the world drastically. However, there is loss of billions of liters of water every year due to leakages in water distribution systems. Such water loss means significant financial loss for the utilities as well. World bank estimates a loss of $14 billion annually from wasted water. To address these issues and for the development of efficient and reliable leakage management techniques, high efforts have been made by the researchers and engineers. Over the past decade, various techniques and technologies have been developed for leakage management and leak detection. These include ideas such as pressure management in water distribution networks, use of Advanced Metering Infrastructure, use of machine learning algorithms, etc. For leakage detection, techniques such as acoustic technique, and in recent yeats transient test-based techniques have become popular. Smart Water Grid uses two-way real time network monitoring by utilizing sensors and devices in the water distribution system. Hence, valuable real time data of the water distribution network can be collected. Best results and outcomes may be produced by proper utilization of the collected data in unison with advanced detection and management techniques. Long term reduction in Non Revenue Water can be achieved by detecting, localizing and repairing leakages as quickly and as efficiently as possible. However, there are still numerous challenges to be met and future research works to be conducted in this field.

• 한국수자원학회논문집
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• 제43권9호
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• pp.769-780
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• 2010

'위상적 평가'와 '수리학적 평가'를 통해 수요절점에서 필요한 수량을 필요한 압력으로 충분히 공급할 수 있는지의 여부를 정량화하고 이를 신뢰성의 산정을 위한 기준으로 사용하는 것은 대표적인 상수관망시스템의 신뢰성산정 방법이다. 하지만 '수리학적 평가'를 이용한 수요절점에서의 압력확보 여부를 신뢰성 산정에 사용한 기존의 연구들은 'Demand-Driven Analysis의 사용'과 '사용성의 미고려'라는 두 가지 측면에 있어서 문제가 있다. 또한 비정상상태인 상수관망시스템의 수리모의 적합한 Pressure-Driven Analysis를 이용한 연구들도 신뢰성 산정에 있어 가능공급량만을 고려하고 사용성을 고려하지 않아, Pressure-Driven Analysis의 장점이 효율적으로 사용되지 않은 단점이 있다. 본 연구에서는 기 개발 된 Pressure-Driven Analysis 모형인 HSPDA모형과, 거리척도 방법을 이용하여 수량과 수압을 동시에 고려하는 신뢰성 분석기법을 제안하였다. 제안된 기법을 상수관망에 적용하여 기존의 연구결과와 비교하였고 이를 바탕으로 수립 가능한 신뢰성 확보방안을 제시하였다.

• 한국환경보건학회지
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• 제28권5호
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• pp.42-52
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• 2002

배수관망에서의 박테리아 재 증식은 큰 현안문제로 대두되고 있으며 이를 억제하기 위한 염소소독 또한 발암성의 부산물인 THMs(trihalomethanes)등을 생성시킬 우려 때문에 미국에서는 오존살균처리 또는 나노여과 (nanofiltration) 법으로 대체해 오고 있다. 그러나 종래의 많은 bench scale 실험결과를 통해 이러한 처리 이후에 잔존하는 미량의 유기물(assimilable organic carbon)이 박테리아 재 증식에 계속하여 영향을 주고 있다는 결과가 AOC(assimilable organic carbon)와 박테리아 재증식의 상관관계를 통하여 밝혀지고 있다. 그러나 현재까지 이러한 연구결과를 full-scale규모의 현장시설에서 직접 검토한 예는 없다. 따라서 본 실험은 미국플로리다주에 위치한 두 지역의 full-scale배수관망 시설을 선정하여 실시하였다. 첫 번째 시설은 오존 살균처리를 그리고 다른 한곳은 나노여과와 석회 연수법 (lime softening)을 병행한 처리법을 사용하고 있다. 박테리아 증식은 R2A 배지를 사용하는 HPC(heterotrophic plate counts)법으로 평가했으며 오존이 공급된 배수관망에서의 HPC 는 각 셈플링 지점의 AOC값을 이용한 지수모델과 높은 상관관계가 있음이 판명되었다($R^2$=0.97). 또한 오존처리는 100%이상의 AOC 농도증가를 나타냈다. 나노여과법과 석회연수법을 병행하고 있는 시설에서도 AOC에 근거한 지수모델과 상관관계를 나타냈다($R^2$=0.75). 그러나 BDOC(biodegradable dissolved organic carbon)는 박테리아 증식에 있어 매우 낮은 상관관계 값을 표시했다($R^2$=0.11). 결과적으로 종래의 많은 bench scale실험결과와 같이 AOC는 배수관망에서의 박테리아 증식과 크게 상관관계를 갖고 있는 것으로 밝혀졌다.

• Smart Structures and Systems
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• 제6권5_6호
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• pp.545-559
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• 2010

This paper presents the results of a pilot study and verification of a concept of a novel methodology for damage detection and assessment of water distribution system. The unique feature of the proposed noninvasive methodology is the use of accelerometers installed on the pipe surface, instead of pressure sensors that are traditionally installed invasively. Experimental observations show that a sharp change in pressure is always accompanied by a sharp change of pipe surface acceleration at the corresponding locations along the pipe length. Therefore, water pressure-monitoring can be transformed into acceleration-monitoring of the pipe surface. The latter is a significantly more economical alternative due to the use of less expensive sensors such as MEMS (Micro-Electro-Mechanical Systems) or other acceleration sensors. In this scenario, monitoring is made for Maximum Pipe Acceleration Gradient (MPAG) rather than Maximum Water Head Gradient (MWHG). This paper presents the results of a small-scale laboratory experiment that serves as the proof of concept of the proposed technology. The ultimate goal of this study is to improve upon the existing SCADA (Supervisory Control And Data Acquisition) by integrating the proposed non-invasive monitoring techniques to ultimately develop the next generation SCADA system for water distribution systems.

• 상하수도학회지
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• 제27권4호
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• pp.413-428
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• 2013

In this study, Ant Colony Algorithm(ACO) was used for optimal model. ACO which are metaheuristic algorithm for combinatorial optimization problem are inspired by the fact that ants are able to find the shortest route between their nest and food source. For applying the model to water distribution systems, pipes, tanks(reservoirs), pump construction and pump operation cost were considered as object function and pressure at each node and reservoir level were considered as constraints. Modified model from Ostfeld and Tubaltzev(2008) was verified by applying 2-Looped, Hanoi and Ostfeld's networks. And sensitivity analysis about ant number, number of ants in a best group and pheromone decrease rate was accomplished. After the verification, it was applied to real water network from S water treatment plant. As a result of the analysis, in the Two-looped network, the best design cost was found to $419,000 and in the Hanoi network, the best design cost was calculated to $6,164,384, and in the Ostfeld's network, the best design cost was found to $3,525,096. These are almost equal or better result compared with previous researches. Last, the cost of optimal design for real network, was found for 66 billion dollar that is 8.8 % lower than before. In addition, optimal diameter for aged pipes was found in this study and the 5 of 8 aged pipes were changed the diameter. Through this result, pipe construction cost reduction was found to 11 percent lower than before. And to conclusion, The least cost design model on water distribution system was developed and verified successfully in this study and it will be very useful not only optimal pipe change plan but optimization plan for whole water distribution system.

• 한국환경보건학회지
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• 제32권6호
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• pp.539-542
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• 2006

The objective of this paper is to compare the applicability of assimilable organic carbon (AOC) or biodegradable dissolved organic carbon (BDOC) for quantifying biodegradable organic material (BOM) and bio-stability in distribution systems for a variety of finished waters. The study the data is derived from was part of an AWWARF and Tampa Bay Water tailored collaboration project to determine the effect of blending different waters on distribution system water quality. Seven different finished waters were produced from surface, ground, or brackish water on site and fed 18 independent pilot distribution systems (PDSs), either as single finished water or as a blend of several finished waters. AOC and BDOC have often been used as indicators of bacterial regrowth potential in distribution systems. In this study, AOC was the more useful assay of the two for the BOM concentrations observed in the PDSs. BDOC did not distinguish BOM while AOC did at the low BOM levels from many of the advanced treatments (e.g. RO, $O^3/BAC$). AOC in contrast allowed much more meaningful calculations of the consumption or production of AOC as the blends passed through the PDSs even for very low BOM blends. In addition, meaningful trends corresponding to changes in heterophic plate count (HPC) were observed for AOC but not for BDOC. Moreover, AOC stability was associated with waters produced from advanced membrane treatment.

• 한국방재학회 논문집
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• 제8권4호
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• pp.61-66
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• 2008

상수관망의 노후화에 따른 잦은 파괴로 인해 보다 효율적인 상수관망 모니터링시스템 구축이 중요한 문제가 되었다. 상수관망의 모니터링 시스템의 하나인 "Smart-Pipe 시스템"은 영구적이며 포괄적인 자동화된 형태의 SIM 시스템으로 기존의 모니터링 시스템에 비해 많은 장점을 가지고 있다. Smart-pipe를 도입하기 위해서는 상수관 파괴를 미리 예측하여 갑작스러운 상수관 파괴를 막는 것과 같이 smart-pipe 설치를 통해 발생하는 간접적 이익의 정량화가 우선되어야 한다. 그러나 이와 관련된 연구는 국내외적으로 매우 미비한 실정이다. 본 연구에서는 smart-pipe의 개념을 기존 상수관 모니터링 시스템과 비교하였으며 smartpipe 설치에 따른 이익을 수용가불편시간으로 정량화하는 방안을 제시하였다. 제안된 방법을 고양시의 상수관망에 적용하여 적용성을 검증하였으며, smart-pipe시스템의 도입을 위한 기초자료로 활용될 수 있을 것으로 판단되었다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2005년도 학술발표회(2)
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• pp.1455-1456
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• 2005

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 1995년도 학술발표회 논문집
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• pp.390-396
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• 1995

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 1998년도 학술발표회 논문집
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• pp.499-504
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• 1998