• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.527-528
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• 2007

A field-oriented UHF system for on-line PD monitoring of transformers is designed, which has been installed inside the oil tank of a 220kV transformer in a substation. 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.

• KSBB Journal
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• v.17 no.4
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• pp.339-344
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• 2002

Flow injection analysis technique for monitoring of xylitol concentrations in biological processes has been developed using xylitol oxidase (XYO) immobilized on VA-Epoxy Biosynth carrier. The immobilized XYO cartridge has been integrated into a FIA system with an oxygen electrode and systematically investigated with regards to the factors which can affect the activity of the immobilized XYO, such as pH, temperature, salt concentration etc. The activity of the immobilized XYO increased with the temperature ($19.0 - 29.0^{circ}C$) and sample injection volume ($75-250\muL$) and molarity of potassium phosphate buffer (0.1-1 M), but it reached the highest value at pH 8.5. The XYO-FIA system has been also applied for on-line monitoring of xylitol concentrations in a reactor and showed good operational stability and agreement with off-line data measured with HPLC.

• Journal of Radiation Protection and Research
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• v.19 no.2
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• pp.147-156
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• 1994

On-line gamma monitoring system around KAERI-site was set up to monitor the radiation fluctuations in environment. Data on gamma exposure rates measured by the ionication chamber in the monitoring posts are transmitted to a computer of central control station with. radio telemetry transmission modem and monitored in real time. Radio telemetry transmission system is economical and reliable on handling and storing of data. This monitroing system can triger an early warning system in the event of abnormal radiation levels.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.5
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• pp.75-81
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• 2007

In this paper, the survey and the analysis of domestic and foreign for on-line monitoring system at low voltage facilities example for value added service about electrical safety were executed. According to survey, in Japan, they are executing the on-line electrical facilities monitoring in based on IT basic law for the information of society construction and not only electrical safety but also value added service such as alarm for earthquake, security are being done. In USA and Europe using power line communication(PLC), the on-line observation and building district management service were being realized. Observing the domestic case, electrical safety related with service such as distribution panel product incorporating load management and leakage current measurement was being executed in some companies. From the survey, it is necessary to improve on the law and the system for market activity in domestic.

• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.193-195
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• 2003

This paper presents an approach to estimate the power transmission line parameter by phasor measurement units(PMUs), which are synchronized to 1 pps signal of GPS. Existing approaches to estimate power transmission line parameter, are mainly off-line ones, based on faults or switching events on other neighboring lines. In this paper, to obtain static and dynamic properties of power transmission line parameter in service, the prototype of pmu-based Transmission Line Parameter Monitoring System (TLPMS) is proposed. Also, an technique to estimate parameters of transmission line described as 2-port network model and the soundness of estimated parameters are addressed.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.12
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• pp.1313-1320
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• 2012

Condition monitoring of the reciprocating compressor is important task. As a traditional method, health monitoring system of refrigerator depends on decision of a skilled person based on his experience. However, the skilled person cannot monitor all the compressors completely. If a sampled compressor is faulty, thousands of compressors manufactured at that place are regarded as faulty compressors. Therefore it is necessary to monitor all compressors in the production line. In the paper real time health monitoring system is developed based on high order time frequency method and artificial neural network. The system is installed in the mass production line. The result of the application has been very successful, and currently the system is working very well on the production line.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.1
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• pp.79-86
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• 2008

Domestic and foreign follows the trend which is that safety checkup of electrical facilities is serviced by on-line system with joining information technology. This paper research improvement of what kind of system and law for market environment of electric power value added service. For improvement of market environment of electric power value added service, this paper researches improvement of on-line monitoring system and necessity of arc interruption and revision of arc related law.

• Proceedings of the KIEE Conference
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• 2008.04b
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• pp.96-99
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• 2008

On-line condition monitoring is a useful tool for maintaining and extending the longevity of power transformers. An intelligent diagnostic system is desirable for operational safety and reliability. Bringing these concepts together results in a powerful support tool for engineers, reducing the volume of data to deal with, and making the data more meaningful. This paper describes how a multi-agent system for diagnosing the cause of transformer partial discharge activity was coupled with a method of UHF partial discharge monitoring, creating an on-line condition monitoring system. The challenges presented by the on-site environment are discussed, along with the implications for the complete system.

• Journal of Korean Society for Atmospheric Environment
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• v.25 no.6
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• pp.523-538
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• 2009

Recently, there has been a keen demand for real-time automatic monitoring of VOCs not only in Korea but other developed countries. We carried out this study to evaluate and to optimize the performance of a continuous automatic monitoring system for hazardous VOCs (HVOCs) in the ambient atmosphere, using an on-line GC system. The online system normally consisted of a Nafion dryer prior to a cold trap of an automatic thermal desorption apparatus and a GC system equipped with two detectors, i.e. PID and ECD. Preliminary tests conducted to check out any contamination of the system revealed an evidence of significant artifact formation of benzene, and it was found that the Nafion dryer (even brand new one) is the source of the benzene artifact. Thus, all the subsequent experiments in this study was carried out inevitably by removing the Nafion dryer. The on-line GC method was investigated with a variety of QC/QA performance criteria such as repeatability, linearity, lower detection limits, and accuracy. In order to find out the best operating condition for the on-line GC system, three different types (in terms of adsorption strength) of cold trap combinations were tested, i.e. (i) Tenax-TA and Carbopack-B combination (weak and hydrophobic); (ii) Tenax-TA, Carbopack-X and Carboxen-1000 combination (strong and hydrophilic); and (iii) Tenax-TA and Carbopack-X combination (medium and hydrophobic/hydrophilic). The USEPA TO-17 manual method was selected as a reference method to evaluate the performance of the on-line method. A series of experiments revealed that the system performance was superior to others when a cold trap packed with hydrophilic adsorbents (Tenax-TA/Carbopack-X/Carboxen-1000 combination) was used and operated at $25^{\circ}C$. However, the system with a cold trap packed with a combination of Tenax-TA and Carbopack-X is more recommended for field applications since the carboxen-1000 adsorbent is too sensitive to water vapor, and hence the performance of the system might be very unstable to humid samples or during rainy days. Furthermore, the precision and accuracy criteria of the Tenax-TA/ Carbopack-X combination were generally compatible with the triple adsorbents cold trap. The continuous automatic monitoring method is, thus, considered very useful to real-time monitoring to understand the variations of VOCs concentrations in ambient air, as it adopts much simpler procedures in sampling, analysis, and data integration steps than manual monitoring methods. However, it should be noted that there is a high possibility of benzene artifacts formation through the Nafion dryer, which is often installed to remove water vapor in air samples before being adsorbed onto the cold trap. Therefore, if a Nafion dryer is used in any studies of monitoring VOCs, the benzene contamination should be carefully examined before carrying out obtaining the data.

• Analytical Science and Technology
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• v.15 no.6
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• pp.496-501
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• 2002

The electrolyte cathode glow discharge (ELCAD) is a new optical system for direct determination of trace heavy metals in flowing water. ELCAD has been successfully developed for on-line monitoring of heavy metals in flowing water. The application of an atmospheric glow discharge between an electrolyte solution cathode and a platinum rod anode led to the development of stable discharge. The fundamental aspects of new plasma source have been investigated. The fundamental study of ELCAD system has been measured plasma temperature using Einstein-Boltzmann equation after searching Fe atomic emission lines. The spectrum of each elements such as Cu, Pb, Fe, Ni and Cr show only major elemental line and no ionic line possibly due to low temperature plasma source. The detection limits of each elements are also investigated. These informations show that this type of plasma may apply for monitoring of heavy metals in waste water which consists of complex matrix.