• Journal of Korean Society on Water Environment
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• v.31 no.1
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• pp.12-18
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• 2015

In this research, the hydrologic effects between a pre-existing urban landuse and low impact development (LID) applied conditions were compared and evaluated. The infiltration trench and tree box filter that were utilized in LID represent only 1% of the catchment area that they drain. Storm event monitoring were conducted from July 2010 to July 2014 on a total of 22 storm events in both LID sites. After LID, hydrological improvement was observed as the sites exhibited a delay (lag time) or reduction in the magnitude, frequency and duration of runoff and flow peaks as the rainfall progress. In addition, the maximum irreducible peak flow reduction for infiltration trench was found to be 61% and 33% for the tree box filter when rainfall was 40 mm and 30 mm, respectively. In designing LID, it is recommended to consider the storage capacity and catchment area, as well as the amount of rainfall and runoff on the site.

• Journal of Korea Water Resources Association
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• v.44 no.12
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• pp.991-1000
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• 2011

The relationship between discharge (Q) and suspended sediment (SS) concentration often is used for the estimation of inflow SS concentration in reservoir turbidity modeling in the absence of actual measurements. The power function, SS=aQb, is the most commonly used empirical relation to determine the SS load assuming the SS flux is controlled by variations of discharge. However, Q-SS relation typically is site specific and can vary depending on the season of the year. In addition, the relation sometimes shows hysteresis during rising limb and falling limb for an event hydrograph. The objective of this study was to examine the hysteresis of Q-SS relationships through continuous field measurements during flood events at inflow rivers of Yongdam Reservoir and Soyang Reservoir, and to analyze its effect on the bias of SS load estimation. The results confirmed that Q-SS relations display a high degree of scatter and clock-wise hysteresis during flood events, and higher SS concentrations were observed during rising limb than falling limb at the same discharge. The hysteresis caused significant bias and underestimation of SS loading to the reservoirs when the power function is used, which is important consideration in turbidity modeling for the reservoirs. As an alternative of Q-SS relation, turbidity-SS relation is suggested. The turbidity-SS relations showed less variations and dramatically reduced the bias with observed SS loading. Therefore, a real-time monitoring of inflow turbidity is necessary to better estimate of SS influx to the reservoirs and enhance the reliability of reservoir turbidity modeling.

• Journal of Environmental Impact Assessment
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• v.24 no.5
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• pp.407-419
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• 2015

The unit load of paddy field was estimated by several methods and compared in this study. Four year field study was conducted at the paddy fields located in Yeongsan river and Sumjin river basins. The unit load was estimated by four methods; (1) averaging field monitored load; (2) NIER (National Institute of Environmental Research) method which use EMC(Event Mean Concentration) and runoff ratio of rainfall groups with rainfall weighting factors; (3)method using EMC determined by best fit probability distribution; (4)method using arithmetic mean EMC and runoff ratio. The result of this study showed that the unit loads of water quality constituents by field monitoring was similar to those of NIER method whereas those by probability distribution(log-normal, gamma) method were less than unit loads of NIER method. The unit loads by arithmetic mean EMC and runoff ratio were larger than those by NIER method. The unit load by NIER method showed higher BOD, COD, SS, lesser T-N, and similar T-P values when compared to unit loads determined by MOE in 1995.

• Journal of Preventive Medicine and Public Health
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• v.30 no.4 s.59
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• pp.815-829
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• 1997

This study was performed to assist the employer to establish the effective program for hearing conservation of noisy industry. The study subjects were health care managers of an industry and the study industries were devided into two groups(Group I, 37 industries; have the workers diagnosed as noise-induced hearing loss, Group II, 41 industries; not have the workers diagnosed as noise-induced hearing loss) and the question method carried out through the face to face interview. The contents of questionnaire for OSHA's hearing conservation program(HCP) consisted of seven components: 5 questions of monitoring of employee noise exposures(component 1), 6 questions of the institution of engineering, work practice, and administrative controls for excessive noise(component 2), 8 questions of the provision of each overexposed employee with an individually fitted hearing protector with an adequate noise reduction rating(component 3), 14 questions of employee training and education regarding noise hazards and protection measures(component 4), 9 questions of baseline and annual audiometry(component 5), 3 questions of procedures for preventing further occupational hearning loss by an employee whenever such an event has been identified(component 6), and 1 question of recording keeping(component 7), thus total numbers of questions was 46. The numbers of statistially significant difference(p<0.05) between two groups were 2(25.0%) among 8 questions of component 3, 10(71.4%) among 14 questions of component 4, 3(33.3%) among 8 questions of component 5, 2(6.7%) among 3 questions of component 6, and 17(37.0%) among total 46 questions of questionnaire. Above results showed that the level of HCP acceptance in group I was lower than in group II. Thus employer's understanding about HCP should be precede for the effective hearing conservation program of employee and the adequate hearing protector, training and education, baseline and annual audiometry, and procedures for preventing further occupational hearning loss for hearing conservation would be more emphasized.

• Journal of Korean Society on Water Environment
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• v.23 no.6
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• pp.945-950
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• 2007

The stormwater runoff from paved area are highly polluted because of particulate materials as well as metals from various vehicular activities. The Division of Road Maintenance in Ministry of Construction and Transportation was recently developed the Guidelines of Environment-kindly Road Maintenance. It is actually requiring the BMP construction to control the nonpoint source pollution as based on the TMDL program. This research is carried out in order to define the characteristics of stormwater runoff from the toll-gate of highways since 2006, which is actually one of the main pollutant sources of paved areas. This monitoring is the first phase work for establishing the treatment facilities in the toll-gates. The one of the main characteristics from toll-gate runoff is the first flush phenomenon containing lots of sediments and metal compounds at the beginning of a storm event. Usually it is used to determine the size of treatment facilities and to calculate the reduced pollutant mass in the facility. The research results shows that the mean EMC vaules for heavy metals are determined to $274.3{\mu}g/L$ for Cd, $1,273.4{\mu}g/L$ for Cr, $1,822.0{\mu}g/L$ for Cu, $6,504.9{\mu}g/L$ for Fe, $14,930.3{\mu}g/L$ for Pb, and $714.1{\mu}g/L$ for Zn. Also the metal mass loadings from the toll-gates are calculated using EMC, watershed area and storm duration.

• The Journal of Engineering Geology
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• v.26 no.2
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• pp.177-185
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• 2016

This work investigates whether stress changes induced by an earthquake can be estimated using the deformation measured by high-resolution borehole strainmeters. We estimate the changes in the orientation and magnitude of the principal compression stresses using borehole strainmeter data recorded before and after the M7.2 El Mayor-Cucapah earthquake on April 4, 2010. Clear differences in the stress orientations and magnitudes are apparent before and after the event. The change in stress orientation appears related to subtle increases of stress in the tectonic maximum principal orientation, which is in agreement with the earthquake focal mechanism solution. The sudden stress drop at the onset of the earthquake was 10⁻³-10⁻² MPa in the principal orientations. The Coulomb stress transfer model, which can estimate stress transfer, predicts a shear stress increase of (0.1-0.6) × 10⁻² MPa at the strainmeter site, which is in line with the measured data (0.3-0.8) × 10⁻² MPa. Overall, our results suggest that borehole strainmeter data reflect the subtle stress changes associated with earthquake occurrence, and that such data can be utilized for earthquake-related research.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.6
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• pp.1310-1316
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• 2014

The IMO has recommended on VHF digital communications operation for sailing ships from 2017. And ships more than 5 tons is obliged to digital communications by fishing Vessels Act and Vessel Safety Act in domestic. The owner of all vessel is equipped to the automatic position reporting device in accordance with the Notice of the Ministry of Oceans and Fisheries to regulations, It shall be ensure to navigations safety and in order to respond quickly in the event of maritime accidents on all vessels. The info-communications station of fishery is operating the automatic position reporting system using the VHF DSC in east sea from 2012, Continuously, which is underway the install plan in south sea and yellow sea. But this plan is very difficult, because of propagation environment is poor on account of complicated coastline and many islands. This paper has analyzed the propagation coverage for position setting of coast station in south sea and the traffic zone set up by compare with RSSI and methode of navigation tracking by VMS.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.27 no.6
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• pp.639-647
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• 2009

In line with the rapid settlement of information society, the demand for geospatial information and its applications are dramatically increasing. The Project of National Geographic Information System(NGIS) is actively on going to meet up-to-dateness and accuracy of geospatial data. It is fact that the public interest in environmental issues is increasing than ever in accordance with the restoration of the four major rivers, core project of Green New Deal Policy, and the event of the Ramsar General Meeting. Because the Nakdong River Estuary is a place of great importance in both aspects of wetland and environment conservation, a variety of researches related to this area are progressing. Although artificial developments and natural phenomena are rapidly changing the topography and ecosystem of this area, the effort to build topographic DB for change monitoring is very slow. This study describes a Lidar surveying project over the restored wetland Eulsukdo, the southermost part of the Nakdong River, to establish precise topographic DB throughout producing 3D topographical maps and wetland classification maps. The results of this study will make a large contribution to the systematic maintenance and management for the restored Eulsukdo wetland.

• Journal of Korea Water Resources Association
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• v.53 no.11
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• pp.1015-1024
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• 2020

Recently, water pollution accidents have continued to occur in pipelines such as red water Incheon and Seoul. In order to recognize this water quality problem, it is necessary to install a water quality sensor in an appropriate location and measure it in advance to detect or block the water supply to the water faucet of the shelter. However, there are limitations, such as maintenance costs, to installing multiple water meters in all pipelines. Therefore, this study proposed a methodology for determining and prioritizing the installation location of flow-based water quality sensor for the recognition of water quality problems in pipelines. We applied the proposed procedure to the pipe break scenario. The results of the determination of the location of the water quality sensor were presented by applying it to the pipe network that actually operates the emergency pipe in Korea. The result of the decision showed that in the event of abnormal situation caused by the destruction of individual pipes, the flow rate of the pipes around the aqueduct and the tank may change rapidly, resulting in water quality accidents caused by turbidity. In the future, it is expected that the water quality monitoring point selection method, such as establishing an external pipe operation plan for pipe cleaning, will utilize the procedure for determining the location of the water quality sensor according to the velocity.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.2
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• pp.404-412
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• 2011

More recently, variety RFID (Radio Frequency Identification) readers are produced by RFID equipment manufactures. Although a transmission standard instituted by EPCglobal is proposed for data transmission between the RFID readers and tags, other RFID reader protocols and the communication connection methods are be in use in other RFID companies. To replace or add the RFID readers of an RFID system, the developers should make changes to the core of the application and/or middleware. In this paper, we propose an RFID reader framework which can manage RFID readers without having to make changes the code of the application in environment with the growing number of heterogeneous RFID readers.This framework that sits on the layer between the RFID readers and the applications provides transparency to the RFID readers. Additionally, it can be used for monitoring the state and the property of all connected RFID, and for recording the RFID tag event logs and system logs. By using this framework, heterogeneous readers can be replaced and added without writing additional code in the applications. Consequently the readers can be easily managed and controlled by the RFID system administrator.