• Atmosphere
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• v.15 no.2
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• pp.75-90
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• 2005

This study examines the impacts of land cover changes on the East Asia summer monsoon with the National Center for Atmospheric Research Regional Climate Model (NCAR RegCM2), coupled with Biosphere Atmosphere Transfer Scheme (BATS). To assess the goals, two types of land cover maps were used in the simulation of summer climate. One type was NCAR land cover map (CTL) and the other was current land cover map derived from satellite data (land cover: LCV). Warm and cold surface temperature biases of $1-3^{\circ}C$ occurred over central China and Mongolia in CTL. The model produced excessive precipitation over northern land area but less over southern ocean of the model domain. Changes of biophysical parameters, such as albedo, minimum stomatal resistance and roughness length, due to the land cover changes resulted in the alteration of land-atmosphere interactions. Latent heat flux and wind speed in LCV increased noticeably over central China where deciduous broad leaf trees have been replaced by mixed farm and irrigated crop. As a result, the systematic warm biases over central China were greatly reduced in LCV. Strong cooling of central China decreased pressure gradient between East Asian continent and Pacific Ocean. The decreased pressure gradient suppressed the northward transport of moisture from south China and South China Sea. These changes reduced not only the excessive precipitation over north China and Mongolia but also less precipitation over south China. However, the land cover changes increased the precipitation over the Korean Peninsula and the Japan Islands, especially in July and August.

• Journal of the Korean Geographical Society
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• v.39 no.5 s.104
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• pp.786-803
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• 2004

These days, interests on land cover classification using not only multi-sensor data but also thematic GIS information, are increasing. Often, although we have useful GIS information for the classification, the traditional classification method like maximum likelihood estimation technique (MLE) does not allow us to use the information due to the fact that the MLE and the existing computer programs cannot handle GIS data properly. We proposed a new method for updating the image classification using multi-spectral and multi-temporal images. In this study, we have simultaneously extended the MLE to accommodate both multi-spectral images data and land cover data for land cover classification. In addition to the extended MLE method, we also have extended the empirical likelihood ratio estimation technique (LRE), which is one of non-parametric techniques, to handle simultaneously both multi-spectral images data and land cover data. The proposed procedures were evaluated using land cover map based on Landsat ETM+ images in the Anmyeon-do area in South Korea. As a result, the proposed methods showed considerable improvements in classification accuracy when compared with other single-spectral data. Improved classification images showed that the overall accuracy indicated an improvement in classification accuracy of $6.2\%$ when using MLE, and $9.2\%$ for the LRE, respectively. The case study also showed that the proposed methods enable the extraction of the area with land cover change. In conclusion, land cover classification produced through the combination of various GIS spatial data and multi-spectral images will be useful to involve complementary data to make more accurate decisions.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.6
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• pp.581-586
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• 2018

Cast iron manhole lids cause environmental pollution during the manufacturing process, and the work environment is very poor. In addition, if the height of the manhole cover does not match the height of the road surface, it causes considerable inconvenience and safety problems. This study proposes a height - adjustable steel manhole cover that can replace cast iron manhole covers and easily match the road surface with the upper surface of the manhole cover. Structural analysis was performed to grasp the design variable of the structure of the manhole cover, satisfying the required quality performance. To fabricate a manhole cover that satisfies the required load capacity, the optimal design for the U-shaped reinforcement structure was made. The cylindrical shape of the height adjustment part and the low frame were formed by bending the steel sheet into a circular shape and then welding. Reinforcing bars were also made by bending a steel plate. The height adjustment groove was machined by a CNC milling machine. Four prototypes were fabricated and a load bearing test was carried out, and new manhole cover was made reflecting results of the test. In the load bearing test, there was no breakage of the welded part, and deformation occurred mainly at the contact area between the groove and gusset plate. Deformation of 1 to 2.7mm occurred due to a load of 450kN. On the other hand, after removing the load, there was almost no residual deformation, and the load bearing evaluation was judged to be satisfactory because the manhole cover could be disassembled and reassembled.

• Journal of Dental Rehabilitation and Applied Science
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• v.29 no.2
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• pp.175-182
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• 2013

The purpose of this study was to observe and analyze the initial marginal bone resorption changes according to the patterns of cover screw exposures during healing period followed by implants installation. Total 64 fixtures(TiUniteTM, NobelBiocare, Sweden) were installed in partially edentulous jaws of 28 patients, who were selected retrospectively and were shown at least one cover screw exposure. Cover screw exposures were defined at 1 month recall. According to the patterns of exposures, groups were categorized into group 1 (No exposure), group 2 (pin-point exposure), group 3 (less than 1/2 of cover screw), group 4 (more than 1/2 of cover screw), group 5 (total exposure). Periapical radiographs were taken in purpose of changes of marginal bone level between installation and 2 month recall. Healing abutments were secured on the exposure groups at 2 month recall. Results were as follows: 1. Marginal bone resorptions were identified whenever cover screws were exposed. 2. Group 2 and 3 were shown significantly increased bone loss more than other group (P <.05). 3. Group 4 and 5 were shown significantly increased bone loss more than group 1, however, less than other groups ( P <.05). Conclusionally, cover screw exposure may cause marginal bone resorptions, therefore, early connection of healing abutment is clinically helpful.

• Korean Journal of Remote Sensing
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• v.22 no.6
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• pp.565-574
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• 2006

Satellite images have been used to obtain land cover information that is one of important factors for hydrological analysis over a large area. In urban area, more detailed land cover data are often required for hydrological analysis because of the relatively complex land cover types. The number of land cover classes that can be classified with traditional multispectral data is usually less than the ones required by most hydrological uses. In this study, we present the capabilities of hyperspectral data (Hyperion) for the classification of hydrological land cover types in urban area. To obtain 17 classes of urban land cover defined by the USDA SCS, spectral mixture analysis was applied using eight endmembers representing both impervious and pervious surfaces. Fractional values from the spectral mixture analysis were then reclassified into 17 cover types according to the ratio of impervious and pervious materials. The classification accuracy was then assessed by aerial photo interpretation over 10 sample plots.

• Journal of Korean Society on Water Environment
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• v.27 no.4
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• pp.425-432
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• 2011

To control non-point source pollution at a watershed scale, rainfall-runoff characteristics from forest watersheds should be investigated since the forest is the dominant land use in Korea. Long-term monitoring would be an ideal method. However, computer models have been utilized due to limitations in cost and labor in performing long-term monitoring at the watersheds. In this study, the Geo-spatial interface to the Water Erosion Prediction Project (GeoWEPP) model was evaluated for its runoff prediction from a coniferous forest dominant watersheds. The $R^2$ and the NSE for calibrated result comparisons were 0.77 and 0.63, validated result comparisons were 0.92, 0.89, respectively. These comparisons indicated that the GeoWEPP model can be used in evaluating rainfall-runoff characteristics. To estimate runoff changes from a coniferous forest watershed with various cover degree scenarios, ten cover degree scenarios (10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%) were run using the calibrated GeoWEPP model. It was found that runoff increases with decrease in cover degree. Runoff volume was the highest ($206,218.66m^3$) at 10% cover degree, whereas the lowest ($134,074.58m^3$) at 100% cover degree due to changes in evapotranspiration under various cover degrees at the forest. As shown in this study, GeoWEPP model could be efficiently used to investigate runoff characteristics from the coniferous forest watershed and effects of various cover degree scenarios on runoff generation.

• Journal of the Korean Association of Geographic Information Studies
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• v.24 no.1
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• pp.12-25
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• 2021

Land cover maps are used in various fields in urban expansion and development. This study analyzed the amount of land cover change over time using multi-sensor information, focusing on the waterfront area of the Taehwa River. In order to apply high-accuracy aerial hyperspectral images, patterns with Field-spectral were reviewed and compared with time series Digital map. The hyperspectral image was set as 13 land cover grades, and the time series digital map was classified into 7 and the waterfront area was classified into 5-6 grades and analyzed. As a result of analysis of the change in land cover of the digital map from the 1990s to 2010, it was found that forest areas were rapidly decreasing and Farmland and grassland were becoming urban. As for the land cover change(2010~2019) in the waterfront area(set 500m) analyzed through hyperspectral images, it was found that Farmland(1.4㎢), Forest(1.0㎢), and grassland (0.8㎢) were converted into urbanized and dried areas, and urbanization was accelerating around the Taehwa River waterfront. Recently, a lot of research has been conducted on the production of land cover maps using high-precision satellite images and aerial hyperspectral images, so it is expected that more detailed and precise land cover maps can be produced and utilized.

• Journal of Korea Society of Industrial Information Systems
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• v.29 no.2
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• pp.27-33
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• 2024

In this paper, the effects of separation distance from a thick radar cover on the performance of 24 GHz band radar was studied through experiments. When a polycarbonate radar cover with a thickness of 10 mm was placed in front of the radar, the variations in radar performance according to the change in the separation distance between the radar and the radar cover was compared with the case without the radar cover. As a radar performance indicator, the distance measured from the radar was used, and the distance was measured using the radar when a person moves away from the radar at a constant speed in the hallway of the building and then approaches again. The separation distance between the radar and radar cover was tested at 2 mm, 5 mm, and 20 mm, respectively. When there was no radar cover, the distance could be measured up to 49.64 m and the error was the lowest. When the separation distance was 2 mm, there was a section where distance measurement was not possible starting from 37.61 m, so the performance was the worst. When the separation distance was increased to 5 mm and 20 mm, the distance was measured up to 49.56 m, but the section where the error between the measured distance and the expected distance was large occurred more often than when there was no radar cover.

• Journal of Environmental Impact Assessment
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• v.22 no.2
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• pp.147-156
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• 2013

Myanmar(Burma) has been preserved valuable environmental resources because of its political isolation. But recently, Myanmar has moved a capital city(Naypyidaw) at central forest area and it has been urbanized radically since 2005. In this paper, we built multi-temporal land cover map from Landsat images of 1970s to 2012 with ENVI 4.5 software. For a broad approach, administrative district Yamethin which includes Naypyidaw is classified into 3 classes and with only Naypyidaw region is classified with 4-5 classes to analyse specific changes. And with forest cover extracted by Object Oriented Classification, we evaluated forest fragmentation before and after the development using Patch Analyst(FRAGSTATs 3.3) at Yamethin area. For Yamethin area, there were significant forest cover change, 51% in 1999 to 48% in 2012, and for Naypyidaw area, 67% in 1999 to 57% in 2012 respectively. Also landscape indices resulted from Patch Analyst concluded that the total edge, edge density and mean shaped index of forest patches increased and total core area is decreased. It is attributed from land cover change with urbanization and agricultural land expansion.

• The Journal of the Acoustical Society of Korea
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• v.36 no.6
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• pp.436-441
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• 2017

Computing music similarity is indispensable in constructing music retrieval system. This paper focuses on the cover song search among various music-retrieval tasks. We investigate the cover song search method based on the chroma n-gram to reduce storage for feature DB and enhance search accuracy. Specifically we propose t-tab n-gram, n-gram selection method, and n-gram set comparison method. Experiments on the widely used music dataset confirmed that the proposed method improves cover song search accuracy as well as reduces feature storage.