• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.2 no.3
• /
• pp.38-46
• /
• 1999

The purpose of the study is to analyze the effect of urbanization, the degree of development in urban scale and the comparative analysis of landuse change in order to construct the important basic data for establishing development direction and characterizing each city. To analyze the urban growth patterns a land cover classification using Landsat TM data was performed : 1987 and 1997 for the change detection of each land cover. The results of this study demonstrates that urban areas increased on while forest areas had decreased all over the Korean cities. Especially, in case of the analysis on landuse conversion rate, we found out that the forest areas was first changed into agricultural areas, then it is consequently developed into urban areas in most rural areas. This study concludes that the insufficiency of the number of knowledged officials in the local administration and a government official in one's charge, tight financial conditions and absence of recognition of cities' characteristics, urban development following unrefined development patterns, inappropriate urban planning and policy of metropolitan cities and the negligence of peculiar development patterns of each city.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.26 no.3
• /
• pp.288-296
• /
• 1998

Natural or human disturbances cause landscape changes, which may be measured by the degree of heterogeneity. In a 16km$\times$19km area, divided into 100m$\times$100m cells, of Seoul city and its suburb, land covers are classified into 6 groups in aerial photos and land use maps. The degree of heterogeneity is defined as the number of cells that surround a central cell but have different land cover from the central cell divided by 8. The value of the degree of heterogeneity is between 0 and 1. Major findings are 1) Both urban and natural areas have low degree of heterogeneity, about 0.15~0.17. 2) Suburban area under heavy pressure of development and urbanization has highest degree of heterogeneity, about 0.25. 3) The peak of the degree of heterogeneity moved about 4.5km outward in 22 years. 4) Outer suburban area has lower degree of heterogeneity as the area is a greenbelt or forest. 5) The results show the areas with higher degree of heterogeneity which may need landscape management plans, and natural areas with lower degree of heterogeneity which may need landscape conservation plans. A landscape change model may be built for a specific city when this technique is applied to multiple sectors of the city, and the model may predict future landscape changes of the city.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 1999.04a
• /
• pp.88-89
• /
• 1999

• Journal of the Korean GEO-environmental Society
• /
• v.10 no.1
• /
• pp.15-23
• /
• 2009

The aim of this study was an evaluation of closed non-sanitary landfill's stabilization degree and a determination of its an optimal reclamation method. In order to evaluate the stabilization degree, physical compositions of landfill wastes in 21 closed non-sanitary landfills were analyzed. There were 4 major items such as cover soils, organics, combustibles and incombustibles. With respect to the results of physical compositions, it was determined that the waste in 9 sampling sites of closed non-sanitary landfills after 10years of the relief time was not fully stabilized. The closed non-sanitary landfills must be reclaimed as soon as possible. The main material in closed non-sanitary landfills was cover soils and the highest content was 89.96%. Otherwise, the contents in sanitary landfills was small and 9.89~11.12%. Therefore, it was evaluated that the recovered soil by sorting transfer treatment could be reused as on-site cover soils of the reclamating non-sanitary landfills and/or constructing materials.

• Korean Journal of Plant Resources
• /
• v.23 no.4
• /
• pp.379-385
• /
• 2010

This study was carried out to develop cultivation techniques of Climacium japonicum in transparent pot. We analyzed effect of different soil moisture content, air exposure degree, bed soil and ground cover moss on the growth of Climacium japonicum. The best humidity condition in transparent pot culture was 60~80% and a mixture of bed soil with peatmoss : perlite as 7:3 ratio was effective to growth. Two holes(each diameter is 4 mm) in the cover were also effective to the growth and control moisture in the transparent pot. The best mixture of bed soil was moss with peatmoss : pelite(7:3) in the pot culture but price of moss is expensive, the moss treatment was not practical. Total of 10 moss species were selected as ground cover plant; Hypnum erectiusculum Sull. et Lesq., Thuidium kanedae Sak., Hypnum plumaeforme Wils., Trachycystis microphylla Lindb., Bryum argenteum Hedw., Hypnum oldhamii Jaeg., Funaria hygrometrica Hedw., Leucobryum glaucum Aongstr., Polytrichum commune Hedw. and Weissia controversa Hedw. The plant height of selected moss was smaller than that of Climacium japonicum so these moss were very effective to cover the ground.

• Journal of the Korea Society of Computer and Information
• /
• v.16 no.7
• /
• pp.85-93
• /
• 2011

The Vertex Coloring Problem hasn't been solved in polynomial time, so this problem has been known as NP-complete. This paper suggests linear time algorithm for Vertex Coloring Problem (VCP). The proposed algorithm is based on assumption that we can't know a priori the minimum chromatic number ${\chi}(G)$=k for graph G=(V,E) This algorithm divides Vertices V of graph into two parts as independent sets $\overline{C}$ and cover set C, then assigns the color to $\overline{C}$. The element of independent sets $\overline{C}$ is a vertex ${\upsilon}$ that has minimum degree ${\delta}(G)$ and the elements of cover set C are the vertices ${\upsilon}$ that is adjacent to ${\upsilon}$. The reduced graph is divided into independent sets $\overline{C}$ and cover set C again until no edge is in a cover set C. As a result of experiments, this algorithm finds the ${\chi}(G)$=k perfectly for 26 Graphs that shows the number of selecting ${\upsilon}$ is less than the number of vertices n.

• Journal of computational fluids engineering
• /
• v.13 no.3
• /
• pp.21-27
• /
• 2008

The reactor head of a sodium-cooled fast reactor KALIMER-600 should be cooled during the reactor operation in order to maintain the integrity of sealing material and to prevent a creep fatigue. Analyzing turbulent natural convection flow in the cover gas region of reactor vessel with the commercial CFD code CFX10.0, the cooling requirement for the reactor head and the performance of the insulation plate were assessed. The results showed that the high temperature region around reactor vessel was caused by the convective heat transfer of Helium gas flow ascending the gap between the insulation plate and the reactor vessel inner wall. The insulation plate was shown to sufficiently block the radiative heat transfer from pool surface to reactor head to a satisfactory degree. More than $32.5m^3$/sec of cooling air flow rate was predicted to maintain the required temperature of reactor head.

• Computers and Concrete
• /
• v.15 no.2
• /
• pp.231-257
• /
• 2015

This paper discusses the spatial variability of the carbonation depth caused by the mesoscopic structure of the concrete and the influence of the spatial variability on the thickness of the concrete cover. To conduct the research, a method to generate the random aggregate structure (RAS) based on polygonal particles and a simplified numerical model of the concrete carbonation at meso-scale are firstly developed. Based on the method and model, the effect of the aggregate properties including shape, content and gradation on the spatial variability of the carbonation depth is comprehensively studied. The results show that a larger degree of the spatial variability will be obtained by using (1) the aggregates with a larger aspect ratio; (2) a larger aggregate content; (3) the gradation which has more large particles. The proper sample size and model size used in the analysis are also studied. Finally, a case study is conducted to demonstrate the influence of the spatial variability of the carbonation depth on the proper thickness of the concrete cover. The research in this paper not only provides suggestions on how to decrease the spatial variability, but also proposes the method to consider the effect of the spatial variability in designing the thickness of the concrete cover.

• Fire Science and Engineering
• /
• v.21 no.4
• /
• pp.52-58
• /
• 2007

The effect of stand-growing-stock characteristics of thinning area and non-thinning area on forest fire was studied in this work. 14 spots were selected from 3 counties such as Yangyang, Injae, and Gapyeong and on-the-spot investigations were performed to evaluate the effect of forest fire. The stand-growing-stock characteristics on the spots were analyzed through the height of tree, breast height diameter, clear length, mortality of branch, forest tree standing crop density, degree of closure, and shrub and grass cover degree. The relation between forest fire and the risk of spread of forest fire were analyzed from the analysis of the stand-growing-stock characteristics. It is considered from this work that the possibility of forest fire is decreased on the thinning area compared to the non-thinning area because of higher clearlength, lower number of tree, lower mortality of branch and higher shrub and grass cover degree.

• The Korean Journal of Applied Statistics
• /
• v.25 no.5
• /
• pp.733-741
• /
• 2012

The successful launch of Arirang satellites allow the acquisition of high resolution satellite imagery of Korean territory and enables the transition from the conventional cultivation area survey method to new image based methods adopted in advanced nations. In this study, we suggested reasonable sizes of the primary sampling unit and the secondary sampling unit for the satellite imagery based sampling design in 8 provinces preselected for this research. The PSU size was determined mainly in consideration of intracorrelation that shows the degree of homogeneity within each cluster and the efficiency of the image process. For the SSU size, we considered the relative standard error and the differences between the land cover maps produced by the Ministry of Environment and the satellite imagery processed by the National Statistical Office.