• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 D
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• pp.2591-2593
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• 2005

본 연구는 물체의 좌우측 상단에 연결된 와이어로프를 모터 및 드럼을 통하여 감아 올리거나 내려 놓는 과정에서 물체가 수평상태를 유지하여 이동될 수 있도록 Two Motor-Two Drum 형식의 권양기를 제어 하는 권양기의 밸런스제어장치에 관한 것이다. 본 연구에 Two Motor-Two Drum 형식의 권양기 제어장치에 있어서, 물체의 상단에 연견된 일측 와이어로프와 타측 와이어로프의 이동길이를 실시간으로 검출하는 와이어로프 이동길이검출부와, 이 와이어로프 이동길이검출부를 통하여 검출되는 일측 와이어로프와 타측 와이어로프의 이동길이를 비교하여 물체의 기울어진 좌 우 편차를 검출하는 편차검출부와, 이 편차검출부를 통해 검출되는 좌우 편차를 제거하기 위하여 일측 또는 타측 와이어로프가 감겨있는 드럼을 회전시키는 모터의 구동속도를 조절하여 물체를 수평상태로 보정하는 밸런스제어부로 구성 되어 있다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2007년도 학술발표회 논문집
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• pp.366-372
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• 2007

본 연구에서는 기 구축된 수도GIS 활용의 활성화 및 정보제공 기반의 체계성을 확보하여 수도관리 업무의 수행에 있어 과학화 달성을 위한 유비쿼터스 기반의 수도관리 방안을 수립하고자 하였다. 이를 위해 기구축된 수도GIS 추진현황 및 GIS DB를 분석하여 최신 IT기술 적용방안을 검토하고, 최신 기술 동향 분석을 통하여 수도GIS의 활용성 극대화를 위한 위치기반서비스(LBS; Location Based Service) 기술을 선정하여 업무전용 모바일 단말기 개발 및 LBS 시스템 설계 구축하였다. 또한, 실시간 수도관리 기술 확보를 위하여 유비쿼터스 기술 및 시스템 활용에 대한 분석을 통해 수도관리 업무의 체계적인 도입을 위한 기술을 검토하여 이를 활용할 수 있는 방안을 제시하였다.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2007년도 동계학술발표대회 논문집
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• pp.612-617
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• 2007

Water meter frost in winter is a nuisance to the water administration and citizen as well. It causes stop of water supply, possibility of accident due to leakage freezing, and additional official work to change frost water meters. This study was carried out to give some basic information of water meter frost condition, to verify the effect of frost protection devices such as lagging vinyl cover, electric heater, and meter pit using subterranean heat. Nearly half of the number of the water meter frost happens in old apartment house with outer corridor, and temperature of the meter box was measured in that kind of apartment house, comparing with atmosphere temperature. The capability of three kinds of lagging vinyl cover was investigated by measuring the inside temperature of the insulated box. Also the capability of existing meter pits and new meter pits using subterranean heat was compared by measuring the inside temperature of the pits. One of the result is that the inside temperature of meter pits using subterranean heat was higher than that of the existing ones, and deeper pit causes higher inside temperature in case of using subterranean heat.

• 한국물환경학회지
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• 제25권1호
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• pp.1-6
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• 2009

• 상하수도학회지
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• 제31권1호
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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.

• 한국환경과학회지
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• 제11권11호
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• pp.1157-1163
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• 2002

The effective removal of microcystins by chlorination was investigated on a laboratory scale. With an initial chl.a concentration of more than 1,000 $\mu\textrm{g}$/ℓ, the required chlorine dose for the effective removal of microcystins from the raw water was more than 8.0 mg/ℓ. Whereas, a chlorine dose of 3.0 mg/ℓcould effectively remove microcystins from raw water containing a chl.a concentration of less than 1,000 $\mu\textrm{g}$/ℓ. The microcystin removal was more effective below pH 8.0, plus the optimum pH range was unrelated to the concentration of toxic algal material. Although chlorination is one of the most effective methods for reducing the toxin from blue-green algae, it causes cell lysis and toxin release. However, it was demonstrated that the released cell lysates and toxins could be effectively removed by a higher dose of the oxidant. The highest removal efficiency of dissolved microcystins(initial concentration: 280 $\mu\textrm{g}$ L$\^$-1/) was with a chlorine dose of 5.0 mg/ℓ.

• 한국물환경학회지
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• 제26권2호
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• pp.261-267
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• 2010

In order to evaluate the distribution level of Cryptosporidium and Giardia in drinking water resources, distribution of Cryptosporidium and Giardia was studied in intake water of main water treatment facility with treatment capacity over 50,000 ton/day in Korea. 10 L samples from each study sites were collected quarterly for 2 years between Oct. '04 and Dec. '07. Cryptosporidium and Giardia were filtered and concentrated by capsule filter and centrifugation, and analyzed by immunomagnetic separation process and fluorescent assay. Cryptosporidium oocysts and Giardia cysts were detected in 7.0% and 9.3%, respectively, of a total 776 samples from 97 study sites. And mean detection number of Cryptosporidium oocysts and Giardia cysts in total 776 samples was 0.11/10 L, 0.16/10 L, detection range of Cryptosporidium oocysts and Giardia cysts was 0~7/10 L, 0~4/10 L, respectively. In seasonal distribution, Cryptosporidium was more frequent in spring as 9.2% than other season, Giardia was more frequent in winter as 14.6% than other season, but there was not shown significant seasonal characteristics. In correlation analysis with total 776 data, Cryptosporidium had significant correlation to total coliforms at the 0.05 level, but correlation value was too low as 0.07 (r=0.07). In case of Giardia, what had significant correlation at the 0.05 level was total coliforms and fecal coliforms, but correlation value was too low as 0.26, 0.27 respectively.

• 한국해양바이오학회지
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• 제16권1호
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• pp.63-86
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• 2024

This study analyzed the distribution, diversity, and density variation of algal clusters in a freshwater reservoir from an oceanic island and a traditional inland water system to gain insights on future marine freshwater resource management. In the Paldang water system (Han River), despite the upstream Paldang Dam and the downstream Jamsil underwater reservoir being in the same meteorological zone, their algae density patterns varied inversely. The distinct algal cluster structure (diversity/dominance) of Paldang was altered in the downstream reservoir, suggesting that physical devices aid algae management in traditional water systems. In contrast, 24 out of 35 genera (63.2%) identified in the Jeolgol Reservoir (Baeknyeong Island) were unique, lacking regulatory mechanisms, and existing in a complex ecotone. The desmid Chlorophyceae Cosmarium, adapted to higher photosynthetic stress and low temperatures, dominated in January (38.04%) and August (86.45%) during the periods of extreme photosynthetic stress. Jeolgol's annual algal cluster structure (H' 2.097; D 0.259; S' 35) demonstrated higher stability than Paldang (H' 1.125; D 0.448; S' 13) and the Jamsil underwater reservoir (H' 1.078; D 0.469; S' 12), maintaining an H' above 1.5 even during midwinters. No evidence of TN/TP inflow from surrounding soils was observed, even during torrential rainfalls, with phosphorus being the limiting factor for algal growth. TOC, BOD, chlorophyll-a, and turbidity peaked during Cosmarium bloom. Future climate change is expected to cause fluctuations in algal clusters and related water quality factors. The complex transitional nature of the Jeolgol Reservoir, its algal diversity, and the interspecies interactions contribute to the high stability of its algal community.

• 한국환경보건학회지
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• 제32권1호
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• pp.53-59
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• 2006

This study was carried out to investigate the physicochemical characteristics with the elapsed time of $1\~10$ minutes after adding green tea leaves in the tap water. The results are summarized as follows: 1. $UV_{254}$ measurement increased sharply in direct opposition to increasing conductivity slowly. It is expected that the water soluble organic matters were better extracted than minerals. 2. Residual chlorine decay coefficients evaluated by assuming first-order reaction was increased in proportion to adding weights of green tea leaves. 3. In DBP formation experiments, residual chlorine decreased when reaction time was elapsed. whereas DBPs such as HAAs and THMs increased with the passing of time. From these results, it was showed that residual chlorine decay was related with the formation of DBPs. Therefore, use of boiled tap water in preparation of green tea is suggested if the residual chlorine in the tap water is high.

• 상하수도학회지
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• 제23권5호
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• pp.637-645
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• 2009

To understand the financial situation of waterworks, the revenue and operation cost from 1996 have been analyzed. The budget of waterworks was 3,775 billion won in 1996 and grew up to 5,774 billion won in 2007. The budget has grown about 1.53 times during 11 years. Based on 2007, total cost for supplying water, rehabilitating old facilities and returning debt and its interest was 4146 billion won. The cost was recovered by 2,825 billion won of water revenue, 827 billion won of various fees revenue, 571 billion won of financial grant and 89 billion won of loan. Until 2007, the 15.3% of operation cost for waterworks was covered by government grant and loan. The renovation cost for old non-efficient facilities was 1,356 billion won in 1996 and was 1,486 billion won in 2007. The renovation cost was not increased remarkably during 10 years. Since the total operation cost was increased about 1.5 times, the percentage for renovating old facilities was decreased from 36% to 25.7%. This trend need to be alerted because the renovation has been slow down when the facilities for water supply need more rehabilitation.