• Journal of the Institute of Electronics Engineers of Korea SC
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• v.44 no.1
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• pp.1-11
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• 2007

In this paper, a new fully digital control method for UPS inverter, which is based on the double control loop such as the outer voltage control loop and inner current control loop, is proposed. In the proposed control system, overshoots and oscillations due to the computation time-delay are compensated by explicit incorporation of the time-delay in the current control loop transfer function. The inner current control loop is adopted by an internal model controller. The internal model controller is designed to a second order deadbeat reference-to-output response which means that its response reaches the reference in two sampling time including computational time-delays. The outer voltage control loop employing P-Resonance controller is proposed. The resonance controller has an infinite gain at resonant frequency, and the resonant frequency is set to the fundamental frequency of the reference voltage in this paper. Thus the outer voltage control loop causes no steady state error as regard to both magnitude and phase. The effectiveness of the proposed control system has been verified by the simulation and experimental results respectively.

• Journal of Environmental Health Sciences
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• v.32 no.5 s.92
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• pp.424-430
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• 2006

Since 1985, the Gangwon Institute of Health and Environment(GIHE) and Ministry of Environment have collected rivers and streams water quality data in an ambient surface water monitering program. This study was prepared to propose an achievement of water quality of rivers subject to management by area according to an created level while establishing a water quality level applicable to the Gangwon area. As a result of evaluating correlativity on the BOD-based water quality data, BOD versus TP, and TP versus SS demonstrated significance at a confidence level of 95%. Evaluating correlativity on $10{\sim}90$ percentile values of analyzed data, a coefficient of determination, $r^{2}$ of BOD versus TP, and TP versus SS were 0.625, 0.286 respectively. Grading the results by evaluation method, the representative values of TP were 0.030 mg/l for I level, 0.100 mg/l for II level, 0.200 mg/l for Ill level, 0.300 mg/l for IV level, and 0.350 mg/l for V level, and those of SS were indicated 4.0 mg/l for I level, 15.0 mg/l for II level, 30.0 mg/l for III level, 45.0 mg/l for IV level, and 60.0 mg/l for V level. As for the limiting factor allowing the water quality standard exceeded, BOD posted 61% as the factor was found in 11 places, TP 28%, and SS 33%.

• The Journal of the Korea Contents Association
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• v.11 no.2
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• pp.457-465
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• 2011

This research, which was started with a need for constant monitoring to find out urban societies and spacial effects by urban railway after the opening, was intended to empirically explore urban and social changes by the opening of Daejeon City metro line 1st which would greatly affect the spacial structure of the city. For this goal, we expected the effect of urban subway on the city with academic consideration and precedent study. Monitoring results of the subway station areas of Daejeon City metro line 1st showed the opening of urban railway had an influence on the flow of urban plan and urban space structure through population, land use, total-developing areas, and land price change. In other words, as urban railway opens the number of population and population activities centered on the subway station areas, and these movements led to the expansion of the commercial areas. Finally, they caused the average land prices to rise. Likewise, urban monitering is significantly useful comprehending the generally time-periodic changes of cities and even conceiving the present cities.

• The Korea Journal of Herbology
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• v.31 no.4
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• pp.93-100
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• 2016

Objectives : The internet is the most common method to investigate information. It is showed that 75.2% of Internet users of 20s had health information search experience. So this study is aim to understanding of interest of public about the herbal medicine using internet search query volume data.Methods : The Naver that is the top internet portal web service of the Republic of Korea has provided an Internet search query volume data from January 2007 to the current through the Naver data lab (http://datalab.naver.com) service. We have collected search query volume data which was provided by the Naver in 606 herbal medicine names and sorted the data by peak and total search volume.Results : The most frequently searched herbal medicines which has less bias and sorted by peak search volume is 'wasong (와송)'. And the most frequently searched herbal medicines which has less bias and sorted by total search volume is 'hasuo (하수오)'.Conclustions : This study is showed that the rank of interest of public about herbal medicines. Among the above herbal medicines, some herbal medicines had supply issue. And there are some other herbal medicines that had very little demand in Korean medicine market, but highly interested public. So it is necessary to monitor for these herbal medicines which is highly interested of the public. Furthermore if the reliability of the data obtained on the basis of these studies, it is possible to be utilizing herbal medicine monitoring service.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.7
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• pp.1544-1550
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• 2013

In recent years, Container Security Device(CSD) using GPS & GLONASS to improve logistics efficiency are being extensively researched. The purpose of this paper is to examine the performance development antenna usable cargo container security transport. Antenna developed by study were optimized to match logistics environment apply to GPS/GLONASS dual frequency for monitering system. The measure of antenna have confirmation about frequency characteristics each 1575.42MHz, 1602MHz and VSWR is 2:1 measured in return loss -9.54dB. Reliability of this antenna has been verified about GPS/GLONASS through test-operation between the south korea and Russia.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2006.11a
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• pp.33-45
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• 2006

The interest of sediment has been increased daily because most of domestic dam reservoir's operation time have been extended and wide basin area is the main characteristics for artificial reservoir which the speed of water flow in artificial reservoir is slower than that of natural reservoir. Therefore a lot of sediment has been significantly accumulated. In this study, the accurate topographic data were obtained using echo-sounding system. GPS survey, low-frequency sub-bottom profiler, and high-frequency echo-sounding system were used to compute the exact amount of sediment. Based on the results, DEM(Digital Elevation Model) and DSM(Digital Surface Model) were generated. The GIS system for the management of sediment was created based on topographic data on the riverbed and this system can be efficiently used for the management of sediment which caused the problems of reservoir capacity and water quality.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.26 no.3
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• pp.219-225
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• 2008

There are many problems in monitering environmental change around of nuclear power station, because interesting area is coastal and relatively large. The ground resolution of Landsat ETM+ imagery is high (30 m), but this imagery does not have enough informations for conducting atmospheric correction in evaluating sea surface temperatures. On the other hand, while it is possible to conduct atmospheric correction using MODIS imagery with it's two infrared bands, it's resolution is relatively low (1 km). Therefore, atmospheric corrected high resolution temperature information can be obtained from these two satellite images. In this study, digital numbers of Landsat ETM+ data in interesting area are georeferenced, converted to effective temperatures based on radiance value, and then the atmospheric correction is conducted using MODIS data. As a result, about $3.5^{\circ}C$ temperature differences were detected in comparing sea surface temperature of the surrounding area of Uljin nuclear power station with it of the same area located 5km far east.

• Journal of Korean Society on Water Environment
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• v.25 no.4
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• pp.615-623
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• 2009

The research of the determination of event mean concentration (EMC) was focussed combined sewer overflows and highway runoff in korea. But those of non-urban areas are few. In this study, EMC and unit loading on land use types in Nogok watershed were estimated by runoff loading of non-point source (NPS) on non-urban area. Two monitoring sites were equipped with an automatic velocity meter, flow meter, and water sampler. Monitoring was conducted at two monitering site during the rainy season. The results show that the EMC ranges in forest land use are 1.3~2.6 mg/L for BOD, 2.0~16.1 mg/L for SS, 0.1~2.1 mg/L for TN, and 0.12~0.49 mg/L for TP. The unit loading of NPS in this study was difficult to compare directly with that used conventionally because of the difference of field investigation. In near future, it needs to conduct more systematic and long-term research about NPS within the watershed. The results of this research can be used to estimate the total pollution load management system (TPLMS) program in korea.

• Journal of Korean Society of Water and Wastewater
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• v.28 no.6
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• pp.647-655
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• 2014

To perform long-term sewer monitoring, It is important to understand the nature of the wastewater flow that occurs at the point on early stage of the monitor and to prevent in advance a problem which may caused. We can infer the flow properties and external factors by analyzing the scatter graph obtained from the measured data flow rate monitoring data since an field external factor affecting the sewage flow is reflected in the flow rate monitoring data. In this study, Selecting the three points having various external factors, and we Inferred the sewer flow characteristics from depth-velocity scatter graph and determined the analysis equation for the dry-weather flow rate data. At the'point 1' expected non-pressure flow, we were able to see the drawdown effect caused by the free fall in the manhole section. At the'point 2', existed weir and sediments, there was backwater effect caused by them, and each of size calculated from the scatter graph analysis were 400 mm and 130 mm. At the'Point 3', there is specific flow pattern that is coming from flood wave propagation generated by the pump station at upstream. In common, adequate equations to explain the dry weather flow data are flume equation and modified manning equation(SS method), and the equations had compatibility for explaining the data because all of $R^2$ values are over 0.95.

• Journal of Environmental Impact Assessment
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• v.14 no.2
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• pp.83-96
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• 2005

Brominated flame retardants have the market share of 40%, comparing others because of their low cost and highly effective retardation against the flame. However, their toxic effects in human and properties of the accumulation in the environments have been issued among the international organization such as EU, OECD and etc. It, therefore, was surveyed the classification, toxic effects, and the usage of Brominated flame retardants, the trends for their managements in the world and Korea, and their contaminated levels in Korean Peninsula. In addition, the management directions for them were proposed. Penta, octa, and deca-BDE among brominated retardants will seem to be prohibited by the regulation as a flame retardants for plastics in Europe because of their toxic effects. Although Penta and Octa BDEs was used marginally in Korea, deca-BDE was 27% of brominated flame retardants (49,050 ton) which had been used in 2002. However, risk assessment for brominated retardants might not launched in Korea, yet. These reports demonstrate that toxic brominated retardants such as PBDEs will be assessed for their usage and the level of contamination in the environment in the area of the point sources like the industrial areas, incinerators and etc. However, the law to regulate the hazardous chemicals seems not to be dictated the monitoring of their contamination in the environment. We, therefore, suggest how to evaluate and to monitor the toxic contaminants with EIA (Environmental Impact Assessment) and LCA (Life Cycle Assessment) system. Further, to establish the management system of BFRs (such as the monitering of contamination levels in environments, life cycle assessment, and risk assessment for the toxic chemicals), It can be recommended the law to deal with the method analyzing chemicals will be established, which contains QA/QC (Quality Assurance and Quality Control) to evaluate the analytic capability of the companies to prepare EIS (Environment Impact Statement) or other institutes for analyzing chemicals.