• Journal of Environmental Impact Assessment
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• v.21 no.5
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• pp.649-664
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• 2012

The grid cell analysis is used to select good sites as habitats at the region. The northern area of Yeongjong Island, Incheon has been disturbing by habitat loss due to human activities such as residential development, deforestation. In order to determine significant places as bird habitats and to select conservation areas at this island, the study area was divided into 70 grid cells($500{\times}500m$ each grid) and then each grid was ranked by spatial analysis using the species diversity index. Fieldwork was carried out in Spring and Autumn of 2010. To examine grid cells which were ranked high in both seasons in common, we used the average ranking value, combined data from two seasons. This area consists of mainly agricultural areas and forests(more than 68%) among eight habitat types: the agricultural land, forest, coast, lake, meadow, stream, city and other things. A total of 110 species was recorded: 4,183 birds of 102 species in Spring and 3,326 birds of 58 species in Autumn. In other words, the number of individuals and species was higher in Spring than in Autumn. Species diversity index presented the highest value at M8 grid cell in Spring(3.380) and at A4 gird cell in Autumn(2.736). In 18 of 22 grid cells where the average ranking value was higher than 3, the forest was distributed and in 4 grid cells, the coast and wetland were widely distributed, in which theses were located apart from human-associated disturbances such as construction works for a leisure complex. Our results present a new estimate method not only to minimize loss of bird habitats but also to conserve important habitats when the large-scale development takes place at particular region.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.6B
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• pp.697-707
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• 2008

The grid-based KIneMatic wave STOrm Runoff Model (KIMSTORM) by Kim (1998) predicts the temporal variation and spatial distribution of overland flow, subsurface flow and stream flow in a watershed. The model programmed with C++ language on Unix operating system adopts single flowpath algorithm for water balance simulation of flow at each grid element. In this study, we attempted to improve the model by converting the code into FORTRAN 90 on MS Windows operating system and named as ModKIMSTORM. The improved functions are the addition of GAML (Green-Ampt & Mein-Larson) infiltration model, control of paddy runoff rate by flow depth and Manning's roughness coefficient, addition of baseflow layer, treatment of both spatial and point rainfall data, development of the pre- and post-processor, and development of automatic model evaluation function using five evaluation criteria (Pearson's coefficient of determination, Nash and Sutcliffe model efficiency, the deviation of runoff volume, relative error of the peak runoff rate, and absolute error of the time to peak runoff). The modified model adopts Shell Sort algorithm to enhance the computational performance. Input data formats are accepted as raster and MS Excel, and model outputs viz. soil moisture, discharge, flow depth and velocity are generated as BSQ, ASCII grid, binary grid and raster formats.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.3 no.3
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• pp.151-158
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• 1999

Biogenic source emissions refer to naturally occuring emissions from vegetation, microbial activities in soil, lightening, and so on. Vegetation is especially known to emit a considerable amout of volatile organic compounds into the atmosphere. Therefore, biogenic source emissions are an important input to photochemical air quality models. since most biogenic source emissions are calculated at the county-level, they should be geographically allocated to the computational grid cells of a photochemical air quality model prior to running the model. The traditional method for the spatial allocation for biogenic source emissions has been to use a "spatial surrogate indicator" such as a county area. In order to examine the applicability of such approximations, this study developed more detailed surrogate indicators to improve the spatial allocation method for biogenic source emissions. Due to the spatially variable nature of biogenic source emissions, Geographic Information Systems(GIS) were introduced as new tools to develop more detailed spatial surrogate indicators. Use of these newly developed spatial surrogate indicators for biogenic source emission allocation provides a better resolution than the standard spatial surrogate indicator.indicator.

• Korean Journal of Remote Sensing
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• v.26 no.6
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• pp.693-703
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• 2010

High spectral resolution of hyperspectral data enables analysis of complex natural phenomena that is reflected on the data nonlinearly. Although many manifold learning methods have been developed for such problems, most methods do not consider the spatial correlation between samples that is inherent and useful in remote sensing data. We propose a manifold learning method which directly combines the spatial proximity and the spectral similarity through kernel PCA framework. A gain factor caused by spatial proximity is first modelled with a heat kernel, and is added to the original similarity computed from the spectral values of a pair of samples. Parameters are tuned with intelligent grid search (IGS) method for the derived manifold coordinates to achieve optimal classification accuracies. Of particular interest is its performance with small training size, because labelled samples are usually scarce due to its high acquisition cost. The proposed spatial kernel PCA (KPCA) is compared with PCA in terms of classification accuracy with the nearest-neighbourhood classification method.

• Journal of the Korea Society of Computer and Information
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• v.24 no.8
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• pp.137-142
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• 2019

This paper proposed bitmap based spatial data transmission scheme in need of rapid transmission through network in mobile environment that use and creation of data are frequently happen. Former researches that used clustering algorithms, focused on providing service using spatial data can cause delay since it doesn't consider the transmission speed. This paper guaranteed rapid service for user by convert spatial data to bit, leads to more transmission of bit of MTU, the maximum transmission unit. In the experiment, we compared arithmetically default data composed of 16 byte and spatial data converted to bitmap and for simulation, we created virtual data and compared its network transmission speed and conversion time. Virtual data created as standard normal distribution and skewed distribution to compare difference of reading time. The experiment showed that converted bitmap and network transmission are 2.5 and 8 times faster for each.

• Journal of Korean Society for Geospatial Information Science
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• v.20 no.1
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• pp.109-116
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• 2012

The effect of the grid resolution on the hydrodynamic simulation has been investigated by using CCHE2D and EFDC. Since a high resolution of the grid results in the increase of computation time, an appropriate grid resolution should be selected by considering the efficiency of simulation according to the objectives of projects. In order to understand the effect of grid resolution and determine the optimal grid resolution, several cases with different lateral grid resolutions have been simulated for the reach of Nakdong river at the confluence of Kumho river for the floods in 2006. Orthogonal curvilinear grids for the domain have been constructed from the survey products at the sections with the longitudinal interval of 20 m. Area-elevation curve and the comparison of simulated results with measured stage at the specific station have been used to check the effect of grid resolution. From the results, the existence of optimal grid resolution has been observed, which ensure both efficiency of computation and certainty of results.

• Smart Media Journal
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• v.12 no.4
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• pp.47-57
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• 2023

The hexagonal grid structure has been studied for processing and representing spatial information data in Geographic Information Systems. Visualization using a hexagonal grid has high visibility compared to other grid representation methods. However, it is difficult to effectively convey quantitative data and differences between grids depending on the geospatial data represented. In this paper, we propose a method to visually emphasize the hexagonal grid by generating shadow on the outside of the hexagonal grid. To do so, we offset the outer line segments of the hexagonal grid to be emphasized and generate a Bézier curve based on that information to determine the final shadow shape. We also apply variable transparency toward the edges of the shadow because the shadow gradually fades away from the hexagonal grid. We have shown that the proposed method can effectively generate shadow areas given not only a single hexagonal grid but also multiple hexagonal grids and can generate various shadow shapes based on user interface inputs. We apply the proposed method to Yongsan-gu, one of the districts of Seoul, and show the results of visually emphasizing it after generating shadow using the proposed method.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.12 no.5
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• pp.28-41
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• 2009

Because fire has significant impacts on fauna and flora in forest ecosystems, as well as socioeconomic influences to local community, it has been an important field of study for decades. One of the most common ways to reduce fire risk is to enhance fire-resilience of forest through fuel treatments including thinning and prescribed burning. Since fuel treatment can't be practiced over all forested areas, appropriate and effective strategies are needed. The present study aims to look at the relationship between spatial characteristics of forest structure measured with landscape pattern metrics and burn severity to provide guidelines for effective fuel treatments. Samchuck fire was selected for the study, and 232 grids covering the study areas were generated, and the grid size was 1km. The burn severity is measured with dNBR derived from satellite imagery, and spatial characteristics of forest structure were measured using FRAGSTATS for both landscape and class levels for each 1km grid. The results of this study strongly indicated that heterogeneity in composition and configuration of forests may significantly reduce burn severity. By enhancing heterogeneity of forests, fuel treatments for fire-resilience forest could be more effective.

• Journal of Korea Spatial Information System Society
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• v.10 no.1
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• pp.29-40
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• 2008

With the spread of mobile devices and advances in communication techknowledges, the needs of application which uses the movement patterns of moving objects in history trajectory data of moving objects gets Increasing. Especially, to design public transportation route or road network of the new city, we can use the similar patterns in the trajectories of moving objects that move on the spatial network such as road and railway. In this paper, we propose a spatio-temporal similar trajectory search algorithm for moving objects on road network. For this, we define a spatio-temporal similarity measure based on the real road network distance and propose a grid-based index structure for similar trajectory search. Finally, we analyze the performance of the proposed similar trajectory search algorithm in order to show its efficiency.

• Journal of Environmental Science International
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• v.24 no.4
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• pp.505-514
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• 2015

The grid-based water balance of watershed scale was assessed in the mountainous area of Pyosun catchment in Jeju Island after analyzing precipitation, evapotranspiration, and runoff from January 2008 to December 2013. The existing results of direct runoff, evapotranspirtion, and groundwater recharge comparing to precipitation were presented 22.0%, 25.6%, and 52.4%, respectively, in Pyosun catchment. However, this study indicated each component shows 14.5%, 24.2%, and 61.0%, respectively, in the mountainous area of Pyosun catchment. Therefore, groundwater recharge rate in the mountainous area appears higher than 10% comparing to the overall catchment. It would be analyzed that the amount of direct runoff is relatively small. Moreover, this difference could be generated because of the spatial discontinuities in the process of estimating the total amount of precipitation in the mountainous area. Therefore, the grid-based spatial analysis to maximize the spatial continuity would be useful for providing a more reasonable result when the total amount of water resources are evaluated in mountainous areas in the future.