• 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 the Korean Society of Manufacturing Technology Engineers
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• v.9 no.6
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• pp.127-132
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• 2000

Morphological analysis of wear particles is one of useful methods for machine condition monitoring because it is well reflected in machine driving state. This paper was undertaken to apply to the condition monitoring of hydraulic piston motor. The lubricating wear test was performed under different experimental conditions using the wear test device and wear specimens of the pin on disk type was rubbed in paraffinic base oil by three kinds of lubricating materials, varying applied load, sliding distance. The four shape parameters(50% volumetric diameter, aspect, roundness and reflectivity) are used for morphological analysis of wear particles. The results showed that the four shape parameters of wear particles depend on a kind of the lubricating materials. It was capable of calculating presumed wear volume for three kinds of materials on driving time to foresee as damage condition of lubricating materials.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.2006-2007
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• 2007

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.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.1
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• pp.142-147
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• 2008

Abdominal circumference changes due to breathing by the respiratory muscle activity such as diaphragm, which would partially represent the lung volume variation. The present study introduced conductive rubber molded in a cord shape incorporated with a patient's pants. The conductive rubber cord operated as a displacement transducer to measure the lung or abdominal volume changes. Signal extraction circuitry was developed to obtain the volume and its derivative(or the flow) signals followed by wireless transmission based on the Zigbee communication protocol in a size of $65mm{\times}105mm$ easily put in pocket. Breathing frequency was accurately evaluated and breath pattern analysis seemed feasible, since respiratory behaviours such as maximal inspiration and cough were well identified. Remote wireless receiver module also enabled to monitor both volume and flow signals during resting breathing on a PC terminal.

• Journal of Environmental Health Sciences
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• v.40 no.3
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• pp.204-214
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• 2014

Objectives: Vehicular emissions are one of the main sources of air pollution in urban areas. Correlation analysis was conducted between air pollutants and traffic volume in order to identify causes of air pollution in Gwangju. Methods: Using traffic volumes and air quality monitoring data from 2002 to 2012 from nine stations (seven urban areas, two roadside areas), especially at three sites where traffic volumes were high, the correlation coefficients were obtained between air pollutants as PM-10 (particulate matter), $NO_2$, $SO_2$, CO and $O_3$ at the stations and traffic volumes near the air monitoring stations. Results: Due to traffic volume and distance between the station and the traffic road, concentrations of pollutants at roadside areas were higher than at urban areas, with the exception of $O_3$. The concentration of $O_3$ showed statistically significance with those of other gas materials as $NO_2$, $SO_2$, and CO in winter (p<0.001) and spring (p<0.05). During the period of October 7 to 20, 2012, excluding periods of yellow dust, smog and rainy season, the ratio of $NO/(NO+NO_2)$ showed the highest value 0.57 and 0.40 at Unam and Chipyeong of two roadside stations, followed by 0.35 at Nongseong with vehicular effects. The correlation coefficient between traffic volume and $O_3$, CO, $NO_2$ became higher when the data on mist and haze days were excluded, than when all hourly data were used in that period, at the three sites of Unam, Chipyeong, and Nongseong. Conclusions: Air quality showed a considerable effect from vehicles at roadside areas compared to in urban areas. Air pollutant diminishment strategies need to be aggressively adopted in order to protect atmospheric environment.

• The Journal of Engineering Geology
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• v.29 no.4
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• pp.469-481
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• 2019

In addition to structural stabilization measures such as the construction of Sand Dam, non-structural management measures such as reasonable water demand and supply volume management are needed to prevent limited water supply damage due to drought. In this study, water supply-demand monitoring system was established for drought response in Seosang-ri basin in Chuncheon, the main source of domestic water for small water facilities. The flow rate of the stream was measured for monitoring the supply volume, and the daily flow rate was calculated by using it to calibrate the parameters of the SWAT (Soil and Water Assessment Tool). To monitor demand, the daily usage was calculated by measuring the change in the water level of the water tank. The relationship between the finally calculated daily supply and demand amount was analyzed to identify the shortage of water.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.12
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• pp.1932-1938
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• 2012

The impedance cardiogram has been proposed as a non-invasive, continuous, operator independent, and cost-effective method for cardiac output monitoring. However, it can not be completely considered as non-restrictive method because of attached spot and band type electrodes. Therefore, we developed a improved convenient hand-held typed measurement system for cardiac output by electrical impedance technique. 80 subjects from Yonsei University and the surrounding areas, participated. All subjects measured stroke volume and cardiac output through Physioflow and developed system. To verify the developed system, statistical methods such as correlation, Wilcoxon signed ranks test, and the Bland-Altman analysis were used. The proposed system showed significant correlation in both male and female stroke volume(r=0.715, r=0.704) and cardiac output(r=0.826; r=0.804). From these results, it can be concluded that stroke volume and cardiac output could be improved convenient measurement using the both hands without the help of a specialist.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.3
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• pp.541-550
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• 2021

While open-air compost has value as a source of nutrients for crops in agricultural land, it acts as a pollution that adversely affects the environment during rainfall, and management is required. In this study, it was intended to analyze the accuracy of calculating open-air compost volume using fixed-wing UAV (unmanned aerial vehicle) capable of acquiring a wide range of images and automatic path flights and to identify the possibility of utilization. In order to evaluate the accuracy of calculating the three open-air compost volume, ground LiDAR surveys and precision surveys using a rotary UAV were performed. and compared with the open-air compost volume acquired through a fixed-wing UAV. As a result of comparing the calculation of open-air compost volume based on the ground LiDAR, the error rate of the rotary-wing was estimated to be ±5%, and the error rate of fixed-wing was -15 ~ -4%. one of three open-air compost volume calculated by fixed-wing was underestimated as about -15 %, but the deviation of the open-air compost volume was 2.9 m3, which was not significant. In addition, as a result of periodic monitoring of open-air compost using fixed-wing UAV, changes in the volume of open-air compost with time could be confirmed. These results suggested that efficient open-air compost monitoring and non-point pollutants in agricultural for a wide range using fixed-wing UAV is possible.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.6 no.4
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• pp.52-61
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• 2003

This study was carried out to analyze the effects of stormwater retention and infiltration pond on reduction of flood peak and volume in a experimentally developed ecological pond. The experimental site has 542$m^2$ watershed area, 1,310mm yearly-averaged rainfall. And the area of the retention pond is 60$m^2$, the maximum water depth is 0.5m, the maximum and average storage is 15$m^3$and 9.3$m^3$d. And the area of infiltration pond is 58$m^2$, and the water depth varies 0.2m~0.5m. The monitoring system consists of one rainfall gage, one Parshall flume and acoustic water level gage, two rectangular weirs and acoustic water level gage for discharge gaging, and one data recording unit. Data from ten storm events in total, three storm events in year 2000 and seven storm events in year 2001, were collected. From the data the evaporation rate was achieved with the water balance equation, and the result shows 5.0mm/day in average. The result from the analysis of the effects on reduction of flood peak and volume, is that 14% reduction of flood volume and 15% reduction of flood peak in retention pond and 49% reduction of flood volume in infiltration pond.

• Nuclear Engineering and Technology
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• v.49 no.7
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• pp.1489-1494
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• 2017

The use of a room-temperature gamma spectrometer is an issue in environmental radiation monitoring. To monitor radionuclides released around a nuclear power plant, suitable instruments giving fast and reliable information are required. High-pressure xenon (HPXe) chambers have range of resolution and efficiency equivalent to those of other medium resolution detectors such as those using NaI(Tl), CdZnTe, and $LaBr_3:Ce$. An HPXe chamber could be a cost-effective alternative, assuming temperature stability and reliability. The CEA LIST actively studied and developed HPXe-based technology applied for environmental monitoring. Xenon purification and conditioning was performed. The design of a 4-L HPXe detector was performed to minimize the detector capacitance and the required power supply. Simulations were done with the MCNPX2.7 particle transport code to estimate the intrinsic efficiency of the HPXe detector. A behavioral study dealing with ballistic deficits and electronic noise will be utilized to provide perspective for further analysis.