• Journal of the Korean Geographical Society
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• v.36 no.2
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• pp.126-140
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• 2001

The influence of small urban parks(green ratio is 100%) on the temperature pattern over the urban and its surrounding area was examined by analyzing the case of in and around Changkyeong palace, Changdeok plalace and Jongmyo, Jongro-gu, Seoul. The pattern of temperature over urban parks and their surrounding built-up area was analyzed from September to November 2000, measuring maximum and minimum temperatures with fixed sensors(maximum and minimum thermometer)and real-time temperature depends largely on both the land-use type and the distance from the park border. In the case of maximum temperature, the lowest value appeared on the green area within parks and the highest value on the built-up area far from the green area. The maximum temperature difference between parks and built-up areas was up to $7.3^{\circ}C$. In the built-up area, the maximum temperature of commercial areas was higher than residential areas. In the night time, not only land-use type but also topography is important for the spatial distributlon of temperature because of the cold airflow from adjacet hills. The horizontal temperature profile by mobile measurement is also related to land-use type and to the distance from the park borders. There is a magnitude of $1^{\circ}C$ temperture difference over a distance of 200m and $3~4^{\circ}C$ over a distance of 400m from the park borders.

• Journal of the Korean Association of Geographic Information Studies
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• v.26 no.2
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• pp.42-54
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• 2023

The population is concentrated in the metropolitan areas in Korea, and low-density residential areas are transforming into high density residential areas through redevelopment to meet this demand. However, large-scale redevelopment in a short period of time has a negative impact on the urban climate, such as generating a heat island effect due to the reduction of urban green areas. In this study, the change in surface temperature from 2013 to 2022 in the redevelpment areas of Godeok-dong and Dunchon-dong, Gangdong-gu, Seoul, was analyzed using Landsat 8 satellite images. In the Godeok-dong area, the difference in surface temperature was analyzed for the target redevelopment area, forest area, mixed forest and urban area, and low density residential area. In the Dunchon-dong area, the difference in surface temperature was analyzed for the target redevelopment area, forest area, and low density residential area. The difference in surface temperature was analyzed through multiple regression analysis conducted yearly over the three different stages in redevelopment period. The results from the multiple regression analysis show that in both areas, the land surface temperature of target redevelopment area was higher than that of the forest area and lower than low density residential area. It can be seen that these results occurred because the low-density residential area in Godeok-dong and Dunchon-dong had a lower green area ratio and a higher building-to-land ratio than the target redevelopment area. The results of this study suggest that even if low-density residential areas are transforming into high-density areas, adjusting the management of green areas and building-to-land ratio can contribute to lessen urban heat island effect.

• Journal of the Korean Geographical Society
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• v.40 no.3 s.108
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• pp.296-309
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• 2005

In this study, we investigated the change of future land-surface and relationships of land-surface change with geo-spatial information, using a Bayesian prediction model based on a likelihood ratio function, for analysing the land-surface change of the Gongju area. We classified the land-surface satellite images, and then extracted the changing area using a way of post classification comparison. land-surface information related to the land-surface change is constructed in a GIS environment, and the map of land-surface change prediction is made using the likelihood ratio function. As the results of this study, the thematic maps which definitely influence land-surface change of rural or urban areas are elevation, water system, population density, roads, population moving, the number of establishments, land price, etc. Also, thematic maps which definitely influence the land-surface change of forests areas are elevation, slope, population density, population moving, land price, etc. As a result of land-surface change analysis, center proliferation of old and new downtown is composed near Gum-river, and the downtown area will spread around the local roads and interchange areas in the urban area. In case of agricultural areas, a small tributary of Gum-river or an area of local roads which are attached with adjacent areas showed the high probability of change. Most of the forest areas are located in southeast and from this result we can guess why the wide chestnut-tree cultivation complex is located in these areas and the capability of forest damage is very high. As a result of validation using a prediction rate curve, a capability of prediction of urban area is $80\%$, agriculture area is $55\%$, forest area is $40\%$ in higher $10\%$ of possibility which the land-surface change would occur. This integration model is unsatisfactory to Predict the forest area in the study area and thus as a future work, it is necessary to apply new thematic maps or prediction models In conclusion, we can expect that this way can be one of the most essential land-surface change studies in a few years.

• Journal of Korean Association for Spatial Structures
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• v.8 no.5
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• pp.59-65
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• 2008

Recently, to improve the load carrying capacity of column structures such as bridge piers, application to concrete-filled steel tube(CFT) type columns are increased more and more. To design the concrete-filled steel tube(CFT) columns in accuracy, influence of material and geometry properties and aspect ratio on ultimate strength of the concrete-filled steel tube column is investigated by experimental researches. In this investigation, the ultimate strength distribution of the concrete-filled steel tube column in accordance with diameter-thickness ratio(D/t) and steel-concrete area ratio(As/Ac) are clarified by the compressive tests. Futhermore, parametric experimental investigation on concrete target strength is performed. It was known from experimental observation that ultimate strength of concrete-filled steel tube column under axial compressive loading more depends on section properties of steel tube rather than concrete strength.

• Nuclear Engineering and Technology
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• v.56 no.10
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• pp.4307-4326
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• 2024

This study investigates Equivalent Spherical Diameter (ESD) estimation at high inlet velocity pool scrubbing conditions using the Interfacial Area Transport Equation (IATE) diameter model including bubble-induced turbulence and interphase modeling. The compatibility of area-averaged Sauter Mean Diameter (SMD), areaaveraged Local Equivalent Diameter (LED) and void-weighted area-averaged LED approaches to estimate the ESD are explored and the proposed model is validated against available experimental data. The study reveals that the prevalent constant ESD assumption in pool scrubbing codes is not universal by showcasing a decreasing trend along the column due to intensive bubble breakup. The area-averaged LED approach fails to capture this trend, while the area-averaged SMD and void-weighted area-averaged LED approaches provide accurate estimations aligned with experimental data. Turbulence parameters, interfacial forces, and diameter modeling are identified as crucial for accurate predictions of flow and geometrical variables by setting up the OpenFOAM framework. A sensitivity analysis indicates that the inlet velocity has an acceptable effect on the ESD along the column. The ESD increases near the exit and decreases in the swarm region by increasing the inlet velocities. Turbulent intensity reduces ESD across all column sections while changes in aspect ratio minimally impact ESD. The study shows promise in developing correlations that take into account the spatial variation of ESD in pool scrubbing conditions.

• Economic and Environmental Geology
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• v.37 no.5
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• pp.521-532
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• 2004

The aim of this study is to evaluate the susceptibility of landslides at Kangneung area, Korea, using a Geographic Information System (GIS) and remote sensing. Landslide locations were identified from interpretation of satellite image and field surveys. The topographic, soil, forest, geologic, lineament and land cover data were collected, processed and constructed into a spatial database using GIS and remote sensing data. Using frequency ratio model which is one of the probability model, the relationships between landslides and related factors such as slope, aspect, curvature and type of topography, texture, material, drainage and effective thickness of soil, type, age, diameter and density of wood, lithology, distance from lineament and land cover were calculated as frequency ratios. Then, the frequency ratio were summed to calculate a landslide susceptibility indexes and the landslide susceptibility maps were generated using the indexes. The results of the analysis were verified and cross-validated using actual landslide location data. The verification results showed satisfactory agreement between the susceptibility map and the existing data on landslide locations.

• Journal of the korean academy of Pediatric Dentistry
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• v.49 no.4
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• pp.453-467
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• 2022

The purpose of this study was to evaluate the accessibility of pediatric dental clinics and quantitatively compare the regions with the best and worst accessibility to pediatric dental clinics in South Korea using the geographic information system. Seoul city showed the highest density of pediatric dental clinics, while Gyeongbuk and Jeonbuk provinces showed the lowest density. Seoul city had a service area ratio of 100% in all districts on a 10 km basis. In Gyeongbuk and Jeonbuk provinces, more than half of the districts had a service area ratio of 0%. In Seoul, the average distance from elementary school to the nearest pediatric dental clinic was 3.45 km. The average distance values were 43.66 km and 40.57 km in Gyeongbuk and Jeonbuk provinces, respectively, which were 12.66 times and 11.76 times longer than the average distance in Seoul city.

• Journal of Sensor Science and Technology
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• v.25 no.4
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• pp.280-284
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• 2016

For an arc-flash protection system, the selection of arc-flash sensor in implementation is largely dependent on the coverage area and the spatial resolution. Typically, a point sensor is used to accurately measure an arc event within a very narrow region; whereas, a loop or a line sensor can cover several electrical compartment at the same time, but with a poor resolution. In this work, a novel scheme for an arc-flash sensor was developed by making use of the transmission loss of plastic optical fibers (POFs) to cover a broad range with a high spatial resolution. By relating the amplitude ratio of the arc-signals at the ends of the POF with the arc-location, arc events could be located with a resolution of ~5 cm within a spatial range of 10 m, which has not been reported yet.

• Spatial Information Research
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• v.12 no.4 s.31
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• pp.321-328
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• 2004

The purpose of this study is to describe 3-Dimensional technique to obtain spatial information automatically using PhotoModeler Pro. PhotoModeler Pro is excellent software with the three-dimensional measurement function used by a personal computer using Windows operating system However, it is not sufficient to carry out the automatic matching work with two stereo images. This is very large neck as a 3-D measurement software. In this study, the automatic stereo matching work using the self-making program and DDE interface within PhotoModeler Pro was tried. The experiment field is the hillside and stair zone of Tateyama region, Nagasaki City. The results of automatic stereo matching work were very good with $100\%$ hitting ratio of target.

• Journal of the Korean Association of Geographic Information Studies
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• v.21 no.1
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• pp.12-22
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• 2018

In order to improve the vulnerability of current cities due to climate change, the disaster vulnerability analysis manual for various disasters is provided. Depending on the spatial units, the disaster vulnerability levels, and the conditions of the climatic factors, the results of the disaster vulnerability analysis will have a significant impact. In this study, relative assessments are conducted by adding the eup, myeon and dong unit in addition to census output area unit to analyze the impact on the spatial unit, and relative changes are analyzed according to the classification stages by expanding the natural classification, which is standardized at level four stage, to level two, four and six stage. The maximum rainfalls(10min, 60min, 24hr) are added for the two limited rainfall characteristics to determine the relativity of disaster vulnerable districts by index. The relative assessment results of heavy rainfall vulnerability index showed that the area ratio of disaster areas by spatial unit was different and the correlation analysis showed that the space analysis between the eup, myeon and dong unit in addition to census output area unit was not consistent. And it can be seen that the proportion of disaster vulnerable districts is relatively different a lot due to indexes of rainfall characteristics, spatial unit analysis and disaster vulnerability level stage. Based on the above results, it can be seen that the ratios of disaster vulnerable districts differ relatively significantly due to the level of the disaster vulnerability class, and the indexes of rainfall characteristics. This suggests that the impact of the disaster vulnerable districts depending on indexes is relatively large, and more detailed indexes should be selected when setting up the disaster vulnerabilities analysis index.