• Proceedings of KOSOMES biannual meeting
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• 2003.11a
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• pp.7-11
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• 2003

Ship is being operated under a highly dynamic environments and many factors are related with ship's collision and those factors are interacting. So, an analysis on the ship's collision causes is very important to prepare countermeasures which will ensure the safe navigation. And the analysis confirmed that ship's collision is occurred most frequently and the cause is closely related with human factor. The main purpose of this study is to build a model of human factors in ship's collision cause using SD(System Dynamics} approach and to measure a effect which is risk control countermeasures of ship's collision. To achieve this aim, the structure analysis on the causes of ship's collision using FSM are performed, and the structure was changed by quantitative, qualitative factors and their feedback loops in casual map. This model was performed over 20 years(1993-2012) in a standard simulation model and 8 policy simulation models.

• Proceedings of KOSOMES biannual meeting
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• 2004.05b
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• pp.29-34
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• 2004

Ship is bring operated under a highly dynamic environments and many factors are related whit marine accident and those factors are interacting. An analysis on the marine accident is very important to prepare countermeasures which will ensure the safe navigation This paper aims to build a model of the rouses and improved policy for marine accident using SD(System Dynamics) approach and to measure a effect which is risk control countermeasures of marine accident The methodology of this paper is to perform the causes and improved policy for marine accident using Brainstorming method, and was to changed by quantitutive, qualitative factors and their feedback loops in casual map. This model was performed over 23 years($1997\~2020$) in a standard simulation model and 4 policy simulation models.

• Journal of Navigation and Port Research
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• v.27 no.5
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• pp.493-498
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• 2003

Ship is being operated under a highly dynamic environments and many factors are related with ship's collision and those factors are interacting. So, An analysis on the ship's collision muses is very important to prepare countermeasures which will ensure the safe navigation. And the analysis confirmed that ship's collision is occurred most frequently and the muse is closely related with human factor. The main purpose of this study is to build a model of human factors in ship's collision muse using SD(System Dynamics} approach and to measure a effect which is risk control countermeasures of ship's collision. To achieve this aim, the structure analysis on the muses of ship's collision using FSM are performed, and the structure was changed by quantitative, qualitative factors and their feedback loops in casual map. This model was performed over 20 years(1993-2012) in a standard simulation model and 8 policy simulation models.

• Progress in Medical Physics
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• v.30 no.4
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• pp.104-111
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• 2019

Purpose: Online magnetic resonance-guided adaptive radiotherapy (MRgART), an emerging technique, is used to address the change in anatomical structures, such as treatment target region, during the treatment period. However, the electron density map used for dose calculation differs from that for daily treatment, owing to the variation in organ location and, notably, air pockets. In this study, we evaluate the dosimetric effect of electron density override on air pockets during online ART for pancreatic cancer cases. Methods: Five pancreatic cancer patients, who were treated with MRgART at the Seoul National University Hospital, were enrolled in the study. Intensity modulated radiation therapy plans were generated for each patient with 60Co beams on a ViewrayTM system, with a 45 Gy prescription dose for stereotactic body radiation therapy. During the treatment, the electron density map was modified based on the daily MR image. We recalculated the dose distribution on the plan, and the dosimetric parameters were obtained from the dose volume histograms of the planning target volume (PTV) and organs at risk. Results: The average dose difference in the PTV was 0.86Gy, and the observed difference at the maximum dose was up to 2.07 Gy. The variation in air pockets during treatment resulted in an under- or overdose in the PTV. Conclusions: We recommend the re-contouring of the air pockets to deliver an accurate radiation dose to the target in MRgART, even though it is a time-consuming method.

• Spatial Information Research
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• v.2 no.2
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• pp.165-174
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• 1994

Soil loss was estimated by using universal soil loss equation(USLE) through GIS technique in Buyeu area. The expected soil loss is determined from six environmental factors: rainfall, erodibility of selected soil, length and steepness (gradient) of ground slope, crop grown in soil, and land practices used. A scoring system for assessing soil lossrisk has been developed for calculating SLI(Soil Loss Index) by GIS. The scores of six factors multiplied to give a total score which was compared with an chosen classification system to categorize areas of low, moderate and high risk. Finally, a soil loss assessment map was produced by GIS cartographic simulation technique, and this map could be applied in the establishment of regional land use planning.

• The Journal of the Petrological Society of Korea
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• v.25 no.4
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• pp.325-334
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• 2016

Both 1900 years of historic literature and recent instrumental seismic records indicate the Korean Peninsula has repeatedly experienced small and large earthquakes. This study has used historical and instrumental records of Korea to investigate the characteristics of earthquakes in the peninsula. Results of GIS spatial analyses indicate Pyongyang, the capital of North Korea, is more vulnerable to the earthquake hazard than that of other regions in the Korean Peninsula. It is also noted that Pyongyang is exposed to high risks of other natural and social disasters because of the high population density and concentrated infra structures. Scenario shake map drawn up assuming a magnitude 6.7 earthquake, which was experienced in A.D. 502 in the area, indicates that 51.1% of the city are exposed to PGA 0.24 g or higher. Recent statistics by the Statistics Korea also indicates the North Korea is far more vulnerable to disasters than those in the South Korea. Results of the preliminary study provide essential information for comprehensive understanding of earthquake hazard estimation in Korea including the North Korea.

• Tunnel and Underground Space
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• v.11 no.1
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• pp.64-71
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• 2001

The purpose of this study is to develop rail rockfall and landslide information system to manage spatial database using GIS. For this, a spatial database containing information such as railroad, map, topographic analysis, meteorological data, and rockfall has been constructed for 2.5 km or 5 km buffer zone from the Kyungchun, Youngdong, Jungang, Taebak and Jungsun Rairoad where risk of landslide occurrence potential is high. For management of the spatial database, railroad rockfall and landslide information system has been developed. The information system consists of view, table, chart, layout and project environment. The functions provided in the system are data conversion, editing, labeling, zoom in and out, map making, graphic editing, text DB management, charting, on-line help as well as input, retrieve and output of spatial database. The system was developed using ArcView script language Avenue, and consisted of pull-down menus and icons for easy use. The spatial database and the information system can be used to rockfall and landslide management and analysis near the railroad as basic data and tool.

• Korean Journal of Agricultural and Forest Meteorology
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• v.22 no.3
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• pp.152-163
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• 2020

The present study introduces a procedure to prepare and manage a high-resolution rainfall and soil moisture (SM) database in the LAMP prediction system, especially for landslide researchers. The procedure also includes converting the data into spatial resolution suitable for their interest regions following proper map projection methods. The LAMP model precipitation and SM data are quantitatively and qualitatively evaluated to identify the model prediction characteristics using the ERA5 reanalysis precipitation and observed 10m depth SM data. A detailed process of converting LAMP Weather Research and Forecasting (WRF) output data for 10m horizontal resolution is described in a step-wise manner, providing technical convenience for users to easily convert NetCDF data from the WRF model into TIF data in ArcGIS. The converted data can be viewed and downloaded via the LAMP website (http://df.ncam.kr/lamp/index.do) of the National Center for AgroMeteorology. The constructed database will contribute to monitoring and prediction of landslide risk prior to landslide response steps and should be data quality controlled by more observation data.

• International Journal of Fluid Machinery and Systems
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• v.2 no.2
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• pp.165-171
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• 2009

We developed a 'multi-point vibration acceleration method' for accurately predicting the cavitation intensity in pumps. Pressure wave generated by cavitation bubble collapse propagates and causes pump vibration. We measured vibration accelerations at several points on a casing, suction and discharge pipes of centrifugal and mixed-flow pumps. The measured vibration accelerations scattered because the pressure wave damped differently between the bubble collapse location and each sensor. In a conventional method, experimental constants are proposed without evaluating pressure propagation paths, then, the scattered vibration accelerations cause the inaccurate cavitation intensity. In our method, we formulated damping rate, transmittance of the pressure wave, and energy conversion from the pressure wave to the vibration along assumed pressure propagation paths. In the formulation, we theoretically defined a 'pressure propagation coefficient,' which is a correlation coefficient between the vibration acceleration and the bubble collapse pressure. With the pressure propagation coefficient, we can predict the cavitation intensity without experimental constants as proposed in a conventional method. The prediction accuracy of cavitation intensity is improved based on a statistical analysis of the multi-point vibration accelerations. The predicted cavitation intensity was verified with the plastic deformation rate of an aluminum sheet in the cavitation erosion area of the impeller blade. The cavitation intensities were proportional to the measured plastic deformation rates for three kinds of pumps. This suggests that our method is effective for estimating the cavitation intensity in pumps. We can make a cavitation intensity map by conducting this method and varying the flow rate and the net positive suction head (NPSH). The map is useful for avoiding the operating conditions having high risk of cavitation erosion.

• Journal of the Korean Association of Geographic Information Studies
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• v.6 no.3
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• pp.33-42
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• 2003

As airborne laser scanning technique is developed with high vertical accuracy recently, there come many studies on DEM(digital elevation model creation, building extraction, flood risk mapping and 3D virtual city modeling. This study applied point comparative method, contour comparative method and digital map with scale 1/5,000 to calculate RMSE of DEM in according to resolution that was constructed using rawdata being acquired by airborne laser scanning. As a result, point comparative method showed lower DEM standard error than contour comparative method, it is a reason that contour comparative method was not carried out detailed grid calculation for point comparative method. Also, digital map with scale 1/5,000 showed higher DEM standard error than point comparative method and contour comparative method in below 25.4m that is average horizontal distance among contour line, and showed similar result with contour comparative method in over 25.4m.