• 한국농공학회논문집
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• 제47권3호
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• pp.77-86
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• 2005

A monitoring study has been conducted to identify hydrologic conditions, water quality and nutrient loading characteristics of small watershed in Juam Lake. Climate data of the watershed were collected; flow rate was measured and water quality sampling was conducted at the watershed outlet for this study. Water quality data revealed that T-P concentrations meet I grade of lake water quality standard during non-storm period, but degraded up to II-III grade of lake water quality standard during storm period. The observed T-N concentrations always exceeded lake water quality standard. Therefore, T-P was identified as limiting chemical constituent for eutrophication of Juam Lake. T-P concentration of non-storm period also revealed that point source pollution is not serious in the watershed. Three year monitoring results showed that the observed T-N losses were $10.85\~18.88$ kg/ha and T-P losses were $0.028\~0.323$ kg/ha during six month (Mar. - Oct.), respectively. Major portion of runoff amount discharged by a few storm events a year and nutrient load showed apparent seasonal variation. Huge runoff amounts were generated by intense storms, which make application of water treatment or detention facilities ineffective. Monitoring results confirmed that water quality improvement by abating nonpoint source pollution in rural watershed of monsoon climate should be focused on source control. T-P losses from paddy field seemed to consist of significant amount of total load from study watershed. Therefore, management of drainage from paddy field is considered to be important for preventing algal blooming problem in Juam Lake.

• 전기학회논문지P
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• 제57권2호
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• pp.176-180
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• 2008

A field-oriented UHF system for on-line PD monitoring of transformers is designed, which has been installed inside the oil tank of transformer in a substation by two ways: on-line installing mode through the oil-valve and pre-installing mode through the man hole/hand hole cover. This system has successfully captured long intermittent discharge signals that hadn't been detected through conventional techniques, and solved the problem successfully. The results demonstrate that UHF technique has great advantages for on-line PD monitoring of transformers. By adopting the peak detection technique, it becomes easy and effective for the transplantation of the phase-resolved pattern recognition technique from conventional method to UHF method, and then to realize continuous on-line monitoring, source characterization and trending analysis.

• 한국지열·수열에너지학회논문집
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• 제6권1호
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• pp.29-35
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• 2010

Long-term temperature monitoring has been performed for ground heat exchanger at the Earthquake Research Center (ERC) building in Korea Institute of Geoscience and Mineral Resources (KIGAM). For the 3 years of monitoring, overall temperature increases are observed at various depths within a borehole heat exchanger. But monitoring of ground temperature variation at the monitoring well beforehand showed that geothermal utilization is not the only source for the temperature increase, Because various kinds of sources can cause the ground temperature change, more thorough investigation should be followed.

• 대한전자공학회논문지SP
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• 제47권5호
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• pp.81-88
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• 2010

본 논문에서는 실제 방송 환경에 적용 가능한 방송용 음원 모니터링 시스템을 구축하기 위한 사전연구로 방송 오디오 신호로부터 음악신호 구간을 자동으로 검출할 수 있는 시스템을 제안하였다. 음악구간과 비음악구간의 구분을 위한 특징으로는 사람의 음성 발화 특성을 반영하여 에너지 표준편차와 log 에너지 표준편차 그리고 log 에너지 평균 등 3개의 간단한 시간영역 특징들을 사용하였으며 최종 음악신호 구간 판별은 각 에너지 한계값(threshold)을 이용한 Rule-base 분류를 기반으로 하였다. 실제 FM 라디오 방송 신호를 24시간 녹음하여 진행한 모의실험에서 음악구간 인식률은 96%, 비-음악구간 인식률은 87%를 나타내어 방송용 음원 모니터링 시스템의 전처리기로 손색이 없음을 확인할 수 있었다.

• Nuclear Engineering and Technology
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• 제55권6호
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• pp.2158-2165
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• 2023

Marine radioactivity monitoring is critical for taking immediate action in case of unexpected nuclear accidents at nuclear facilities located near coastal areas. Especially when the level of contamination is not predictable, mobile monitoring systems will be useful for wide-area ocean radiation survey and for determination of the level of radioactivity. Here, we used a silicon photomultiplier and a high-efficiency GAGG crystal to fabricate a compact, battery-powered gamma spectroscopy that can be used in an ocean environment. The developed spectroscopy has compact dimensions of 6.5 × 6.5× 8 cm³ and weighs 560 g. We used LoRa, a low-power wireless protocol for communication. Successful data transmission was achieved within 1.4 m water depth. The developed gamma spectroscopy was able to detect radioactivity from a ¹³⁷Cs point source (3.7 kBq) at a distance of 20 cm in water. Moreover, we demonstrated an unmanned radioactivity monitoring system in a real sea by combining unmanned surface vehicle with the developed gamma spectroscopy. A hidden ¹³⁷Cs source (3.07 MBq) was detected by the unmanned system at a distance of 3 m. After successfully testing the developed mobile spectroscopy in an ocean environment, we believe that our proposed system will be an effective solution for mobile real-time marine radioactivity monitoring.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.1386-1390
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• 2007

This paper presents the equipment condition monitoring technology for the process or the equipment using statistical techniques. The equipment condition monitoring system consists of an empirical model to estimate the expected sensor values of process variables and a diagnose model to detect the abnormal condition and to identify the root source of the problem. The empirical model is constructed by the analysis of historic data. The diagnose model uses the sequential probability ratio test (SPRT) technique. The monitoring system was tested with real operating data acquired from the Reactor Coolant Pump Seal in the Nuclear Power Plant. It can detect the system degradation or failure at the early stage since it is able to catch the subtle deviation of process variables from normal condition.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 춘계학술대회 논문집 센서 박막재료연구회 및 광주 전남지부
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• pp.115-118
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• 2008

A field-oriented UHF system for on-line PD monitoring of transformers. is designed, which has been installed inside the oil tank of a transformer by two ways: on-line installing mode through the oil-valve and pre-installing mode through the man hole/hand hole cover. This system has successfully captured long intermittent discharge signals that hadn't been detected through conventional techniques, and solved the problem successfully. The results demonstrate that UHF technique has great advantages for on-line PD monitoring of transformers. By adopting the peak detection technique, it becomes easy and effective for the transplantation of the phase-resolved pattern recognition technique from conventional method to UHF method, and then to realize continuous on-line monitoring, source characterization and trending analysis.

• Environmental Analysis Health and Toxicology
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• 제16권4호
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• pp.153-159
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• 2001

The main point source of pollution of the Keumho river in Taegu, Korea, stems from waste from the areas of industrial complexes . Although it is widely accepted that pollutants in waste water negatively effects general water quality, it is difficult to evaluate the effluent effect because of varying conditions in ambient water and inconclusive knowledge of causative pollutants. To analyze the water in relation to the industrial effluent in the area, pH. temperature, conductivity, and Microtox toxicity of various river samples were measured. Water samples were collected every 2 hours for 36 hours from Keumho river and Dalseo stream. Data from continuous monitoring for 36 hours showed that effluent in Keumho river originated from Dalseo stream, which is near adjacent to industrial complexes. Change in toxicity and other factors tested during the 36 hours indicated that continuous monitoring was necessary for a satisfactory effluent toxicity test Furthermore, in addition to water quality monitoring, it was concluded that sediment toxicity also needed to evaluate effluent effects.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제55권1호
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• pp.20-25
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• 2006

We suggest a novel temperature detection method utilized in temperature monitoring system. Suggested method detects temperature variation by using $R_{ds(on)}$ characteristics of MOSFET, while conventional methods are using extra devices such as a temperature sensor or an over-temperature detection transistor. For voltage detection between drain and source, 10 bits resolution ADC is needed. Therefore possible measurement signal range is about ten mV. If detected temperature's voltage exceed protection temperature's voltage then controller generates OT (Over Temperature) signal to stop MOSFET's trigger signal. Whole process of measurement is controlled by software. Experimental results show that the developed temperature monitoring system can provide the suitable temperature monitoring method and difference between detected and data sheet value of the suggested system is about $3\%$.

• 한국물환경학회지
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• 제23권4호
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• pp.429-433
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• 2007

Many researchers have made a study of NPS unit-loads and the scientific evaluation method which need for formulating and enforcing a Total Maximum Daily Load (TMDL) management system and modifying a pollutant discharge loadings function. Some showed the event mean concentration (EMC) on single land-use. For the most parts, as the results showed on multiple land-uses, those cannot be used for NPS unit-loads calculation. NPS runoff shows various phenomena depending on rainfall monitoring data, therefore sampling methods and frequency for NPS monitoring must be different from the general monitoring for water quality trend assessment.