• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.32 no.2
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• pp.133-142
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• 2014

Landsat is one of the popular satellites for observing land surface that is used in various areas including monitoring, detecting and classifying changes in land surface. However, shades, which cloud itself and its shadow, interrupted often clear observation and analysis of ground surface. For this reason, the process of removing shades and restoring original ground surfaces are critical for geospatial users. This study is planned to recommend a methodology for more accurate and clear images of Landsat-8 sensor, which provided two additional bands of costal/aerosol and cirrus. In fact, those bands are known as functioned effectively in detecting and restoring shades. Otsu's thresholding technique to detect clouds, we replaced those detective shades by using experimental and reference images. In accurate assessment, the overall accuracy and kappa coefficients were about 85% and 0.7128, respectively. This indicates that the proposed technique is effective for recovering the original land surface.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.3
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• pp.587-593
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• 2019

The field of geospatial information is rapidly changing due to the development of sensor and data processing technology that can acquire location information. And demand is increasing in various related industries and social activities. The construction and utilization of three dimensional geospatial information that is easy to understand and easy to understand can be an essential element to improve the quality and reliability of related services. In recent years, 3D laser scanners are widely used as 3D geospatial information construction technology. However, 3D laser scanners may cause shadow areas where data acquisition is not possible when objects are large in size or complex in shape. In this study, 3D model of an object has been created by acquiring oblique images using an unmanned aerial vehicle and processing the data. The study area was selected, oblique images were acquired using an unmanned aerial vehicle, and point cloud type 3D model with 0.02 m spacing was created through data processing. The accuracy of the 3D model was 0.19m and the average was 0.11m. In the future, if accuracy is evaluated according to shooting and data processing methods, and 3D model construction and accuracy evaluation and analysis according to camera types are performed, the accuracy of the 3D model will be improved. In the point cloud type 3D model, Cross section generation, drawing of objects, and so on, it is possible to improve work efficiency of spatial information service and related work.

• Journal of Space Technology and Applications
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• v.3 no.3
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• pp.199-212
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• 2023

In contrast to the short-term nature of lunar missions in the past, lunar missions in new space era aim to extend the presence on the lunar surface and to use this capability for the Mars exploration. In order to realize extended human presence on the Moon, production and use of consumables and fuels required for the habitation and transportation using in-situ resources is an important prerequisite. The Global Exploration Roadmap presented by the International Space Exploration Coordination Group (ISECG), which reflects the space exploration plans of participating countries, shows the phases of progress from lunar surface exploration to Mars exploration and relates in-situ resource utilization (ISRU) capabilities to each phase. Based on the ISRU Gap Assessment Report from the ISECG, ISRU technology is categorized into in-situ propellant and consumable production, in-situ construction, in-space manufacturing, and related areas such as storage and utilization of products, power systems required for resource utilization. Among the lunar resources, leading countries have prioritized the utilization of ice water existing in the permanent shadow region near the lunar poles and the extraction of oxygen from the regolith, and are preparing to investigate the distribution of resources and ice water near the lunar south pole through unmanned landing missions. Resource utilization technologies such as producing hydrogen and oxygen from water by hydroelectrolysis and extracting oxygen from the lunar regolith are being developed and tested in relevant lunar surface analogue environments. It is also observed that each government emphasizes the use and development of the private sector capabilities for sustainable lunar surface exploration by purchasing lunar landing services and providing opportunities to participate in resource exploration and material extraction.

• Journal of Navigation and Port Research
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• v.48 no.3
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• pp.221-231
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• 2024

The aim of this study was to enhance the safety and care of mental health for seafarer working in passenger ship workspaces. Brightness, color values, and color distribution were investigated with issues and improvement ways identified through seafarers' interviews. Firstly, previous studies, references, current policy, regulations, and accident case studies were reviewed. Color compositions of wheelhouse and engine room of M Ship were then surveyed in the field. Color values of each space were analyzed using a colorimeter. Colormeter analysis of brightness and color measurements in the wheelhouse and engine areas indicated that ceilings, walls, and floors were generally dark, with the engine area being very dark. Regarding color, green and blue were distributed in the ceiling of the wheelhouse and engine area, while red and blue were in the walls and floors of the wheelhouse and engine area. According to interviews with seafarers currently working at engine rooms, they responded about their experience of near miss incidents due to a decrepit indoor environment, a dark working environment, slippery and bright flooring, and stairs that were not suitable for domestic users. Thus, when installing lighting in the future, the brightness of the space should be improved by distinguishing between night and day. A lighting plan considering the location of lighting, level of shadow formation and contrast, reflectance of the facility, glare, color of light, floor color plan, and material selection is needed. A facility design suitable for domestic users is also needed.

• Korean Journal of Remote Sensing
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• v.33 no.6_1
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• pp.931-946
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• 2017

The purpose of this study is to observe and analyze soil moisture conditions with high resolution and to evaluate its application feasibility to agriculture. For this purpose, we used three Landsat-8 OLI (Operational Land Imager)/TIRS (Thermal Infrared Sensor) optical and thermal infrared satellite images taken from May to June 2015, 2016, and 2017, including the rural areas of Jeollabuk-do, where 46% of agricultural areas are located. The soil moisture conditions at each date in the study area can be effectively obtained through the SPI (Standardized Precipitation Index)3 drought index, and each image has near normal, moderately wet, and moderately dry soil moisture conditions. The temperature vegetation dryness index (TVDI) was calculated to observe the soil moisture status from the Landsat-8 OLI/TIRS images with different soil moisture conditions and to compare and analyze the soil moisture conditions obtained from the SPI3 drought index. TVDI is estimated from the relationship between LST (Land Surface Temperature) and NDVI (Normalized Difference Vegetation Index) calculated from Landsat-8 OLI/TIRS satellite images. The maximum/minimum values of LST according to NDVI are extracted from the distribution of pixels in the feature space of LST-NDVI, and the Dry/Wet edges of LST according to NDVI can be determined by linear regression analysis. The TVDI value is obtained by calculating the ratio of the LST value between the two edges. We classified the relative soil moisture conditions from the TVDI values into five stages: very wet, wet, normal, dry, and very dry and compared to the soil moisture conditions obtained from SPI3. Due to the rice-planing season from May to June, 62% of the whole images were classified as wet and very wet due to paddy field areas which are the largest proportions in the image. Also, the pixels classified as normal were analyzed because of the influence of the field area in the image. The TVDI classification results for the whole image roughly corresponded to the SPI3 soil moisture condition, but they did not correspond to the subdivision results which are very dry, wet, and very wet. In addition, after extracting and classifying agricultural areas of paddy field and field, the paddy field area did not correspond to the SPI3 drought index in the very dry, normal and very wet classification results, and the field area did not correspond to the SPI3 drought index in the normal classification. This is considered to be a problem in Dry/Wet edge estimation due to outlier such as extremely dry bare soil and very wet paddy field area, water, cloud and mountain topography effects (shadow). However, in the agricultural area, especially the field area, in May to June, it was possible to effectively observe the soil moisture conditions as a subdivision. It is expected that the application of this method will be possible by observing the temporal and spatial changes of the soil moisture status in the agricultural area using the optical satellite with high spatial resolution and forecasting the agricultural production.

• Korean Journal of Environment and Ecology
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• v.32 no.4
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• pp.425-439
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• 2018

W investigated the environmental factors and inhabiting biota such as macrophytes and zooplankton in 43 sites located on Jeju Island from May and June 2017 to evaluate the spread and ecosystem risk of dotted duckweed (landoltia punctata) which was recently found for the first time in Jeju Island. Dotted duckweeds were found in a total of 18 sites which tended to show low biomass of aquatic macrophyte species other than the dotted duckweed. We conducted a pattern analysis using SOM (Self-Organizing Map), which extracts information through competitive and adaptive properties, to analyze the effect of inhabiting biota on aquatic macrophytes such as the dotted duckweed and environmental factors. The SOM analysis showed that the inhabiting biota such as the zooplankton affected the biomass of aquatic macrophytes than they did the environmental factors. In particular, the biomass of dotted duckweed was positively related to plant-attached species (Alona, Chydorus, and Pleuroxus). Considering that low density of aquatic macrophytes covers the streams and wetlands on Jeju Island because of irregular water source and sharp change of water depth, the dotted duckweeds are likely to play an essential role as the vital habitat for micro-biota including zooplankton in wetlands and streams on Jeju Island. Furthermore, considering that organic matters are utilized as the primary food source in the areas occupied by dotted duckweed, dotted duckweeds have the role of being both habitat and food source. Although the dense growth of dotted duckweed adversely affects growth and development of some aquatic plants due to the shadow effect, it is due to the dominance of floating plants on the water surface should not be regarded as the risk of the dotted duckweed. In conclusion, the dotted duckweeds have spread and settled in most of the water systems on Jeju Island, their impact on inhabiting biota and the aquatic environment was minor. It is necessary to monitor the distribution and spread of dotted duckweeds in the inland areas outside of Jeju Island in the future.

• Journal of the Korean Institute of Landscape Architecture
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• v.50 no.2
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• pp.1-22
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• 2022

The modification effects of street trees on outdoor thermal comfort in summertime according to tree planting types and road direction were analyzed using a computer simulation program, ENVI-met. With trees, the air temperature and wind speed decreased, and the relative humidity increased. In the case of mean radiant temperature (T_mrt) and human thermal sensation, physiological equivalent temperature (PET) and universal thermal climate index (UTCI), there was a decrease during the daytime. The greatest change among the meteorological factors by trees happened in Tmrt, and PET and UTCI showed similar patterns with T_mrt·The most effective tree planting type on thermal comfort modification was low tree height, wide tree crown, high leaf area index, and narrow planting interval (LWDN). T_mrt, PET and UTCI showed a large difference depending on shadow patterns of buildings and trees according to solar altitude and azimuth angles, and building locations. When the building shade areas increased, the thermal modification effect by trees decreased. In particular, results on the east and west sidewalks showed a large deviation over time. When applying the LWDN, the northwest, west and southwest sidewalks showed a significant reduction of 8.6-12.3℃ PET and 4.2-4.5℃ UTCI at 10:00, and the northeast, east and southeast sidewalks showed 8.1-11.8℃ PET and 4.4-5.0℃ UTCI at 16:00. On the other hand, when the least effective type (high tree height, narrow tree crown, low leaf area index, and wide planting interval) was applied, the maximum reduction was up to 1.8℃ PET and 0.9℃ UTCI on the eastern sidewalks, and up to 3.0℃ PET and 0.9℃ UTCI on the western ones. In addition, the difference in modification effects on T_mrt, PET and UTCI between the tree planting types was not significant when the tree effects were reduced by the effects of buildings. These results can be used as basic data to make the most appropriate street tree planting model for thermal comfort improvement in urban areas in summer.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.31 no.3
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• pp.61-74
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• 2013

This study examined and analyzed ancient writing and poetry regarding cases of appreciating plants by using pots in a garden of a palace or private houses by ancestors, and examined shape and planting method of plant species and potted plants, arrangement and preference of potted plants. As for the method of the study, description research method which examines and interprets poem and painting based on potted plants. The results of this study is summarized like the following. First, the plants which were favorably used for potted plants include 19 kinds such as Prunus mume, Pinus densiflora, Pinus pumila, Phyllostachys spp., Camellia japonica, Punica granatum, and Gardenia jasminoidesa, and as for herbs, 12 kinds such as Chrysanthemum monifolium and Nelumbo nusifera . Second, the species which were specially arranged into artificial shapes include Prunus mume and Pinus densiflora. The two plants made the shape of severe curves of stems such as Wangpi. Gyuban, and Bangan, and there are Pinus densiflora dwarfed potted plant whose roots are stretched on Prunus mume grafted into a strange stump and an oddly shaped stone. For the beauty of the dwarfed tree shape, pine cones are added to an old Pinus densiflora or Parthenocissus tricuspidata is planted to stems, and additional method of making moss on the soil, which is called 'Jongbunchuigyeong'. As for planting method, water culture, planting on a stone, planting on a charcoal, and assembled planting are expressed in poetry. Third, as for external space for potted plants, a place where a king stays, a bed room for a king, surrounding areas and gardens of private houses, and step stones were used as a space which adds artistic effects. Potted plants are placed on a table in a library, on a desk, on a drawer, and near a pillow as a small items in a room, and scholars enjoyed original characteristics and symbolism of the potted plants. Fourth, at the time of flowering of Prunus mume, poetry event was held to enjoy the tree and writing poetry begun. And at the time of flowering of Chrysanthemum monifolium, the flowers were floated in a liquor glass or shadow play was enjoyed. Fifth, potted plants played the role of garden ornaments in elegant events of a palace, the gentry, wedding ceremony, and sacrificial rites. Sixth, potted plants were used as tributes between countries, donation to a king, or a gift of a king. In addition, there were many cases where scholars exchanged potted plants and there is the first record of giving a potted plant in 'Mokeunsigo' by Mokeun Isaek, scholar in the late era of Goryeo. Seventh, at the time of flowering Prunus mume, Chrysanthemum monifolium, Gardenia jasminoides, Nelumbo nusifera, and Narcissustazetta var. chinensis, they enjoyed the particular fragrance and express it into poetry. Eighth, plant species from southern parts such as Camellia japonica, Daphne odora, Gardenia jasminoides, Citrus unshiu, Phyllostachys spp., Punica granatum, Rosa rugosa, and Musa basjoo, or foreign plant species, and species weak against the cold were utilized as pot plants for enjoying green trees indoors in northern central province in harshly cold winter.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.35 no.6
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• pp.553-562
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• 2017

GPS (Global Positioning System) receiver among various sensors mounted on UAV (Unmanned Aerial Vehicle) helps to perform various functions such as hovering flight and waypoint flight based on GPS signals. GPS receiver can be used in an environment where GPS signals are smoothly received. However, recently, the use of UAV has been diversifying into various fields such as facility monitoring, delivery service and leisure as UAV's application field has been expended. For this reason, GPS signals may be interrupted by UAV's flight in a shadow area where the GPS signal is limited. Multipath can also include various noises in the signal, while flying in dense areas such as high-rise buildings. In this study, we used analytical photogrammetry and auto tracking total station technique for 3D positioning of UAV. The analytical photogrammetry is based on the bundle adjustment using the collinearity equations, which is the geometric principle of the center projection. The auto tracking total station technique is based on the principle of tracking the 360 degree prism target in units of seconds or less. In both techniques, the target used for positioning the UAV is mounted on top of the UAV and there is a geometric separation in the x, y and z directions between the targets. Data were acquired at different speeds of 0.86m/s, 1.5m/s and 2.4m/s to verify the flight speed of the UAV. Accuracy was evaluated by geometric separation of the target. As a result, there was an error from 1mm to 12.9cm in the x and y directions of the UAV flight. In the z direction with relatively small movement, approximately 7cm error occurred regardless of the flight speed.

• Journal of radiological science and technology
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• v.29 no.4
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• pp.267-274
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• 2006

The evaluation of GB stones with ultrasound has proved to be useful procedure in patient with symptoms of cholelithiasis. GB is evaluated for size, wall thickness, presence of internal reflections within the lumen and posterior acoustic shadowing or enhancement in Ultrsonography. The patient position should be shifted during procedure to demonstrate further the presence of stone within the GB. Patient scanned at the Rt. subcostal region in supine, right lateral, Lt. down decubitus, and upright sitting position. So GB stone should shift to dependent area of GB. Often, GB is not markedly distended in the presence of cholethiasis, and so the diagnosis becomes more difficult. One of the more difficult areas for detection of a GB stones are embeded in the cystic duct region. And since the GB is adjacent to the duodenum and hepatic flexure, its may be difficult to visualizing a GB stone. When patient study position changes frome supine to other position, stones displaced the site. But if its are polyps, not changes the site whatever patient positions. It is very important to what make different GB stones or polyps. We have studied about mobility of GB stones according to the patients position(supine, Lt. down decubitus, $30^{\circ} LAO. sitting and hand-knee). So we have a result, stones wherever localized within the GB, changed 100% its position in the hand-knee position and the others appeared at least 90%. In this study, when a large stones are located through fundus-body and body-neck, does not changing the stones position in spite of varied patient's positions. But hand-knee positions can identified GB stones, because its make changed the position of stons from posterior wall to anterior wall within the GB. We recommend the hand-knee position for differentiation GB stones from polyps.