• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.616-619
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• 2007

Nowadays, urbanized area expands its boundary, and distribution of urbanized area is gradually transformed into more complicated pattern. In Korea, SMA(Seoul Metropolitan Area) has outstanding urbanized area since 1950s. But it is ambiguous whether urban distribution is clustered or dispersed. This study aims to show the way in which expansion of urbanized area impacts on spatial distribution pattern of urbanized area. We use quadrat analysis, nearest-neighbor analysis and fractal analysis to know distribution pattern of urbanized area in time-series urban growth. The quadrat analysis indicates that distribution pattern of urbanized area is clustered but the cohesion is gradually weakened. And the nearest-neighbor analysis shows that point patterns are changed that urbanized area distribution pattern is progressively changed from clustered pattern into dispersed pattern. The fractal dimension analysis shows that 1972's distribution dimension is 1.428 and 2000's dimension is 1.777. Therefore, as time goes by, the complexity of urbanized area is more increased through the years. As a result, we can show that the cohesion of the urbanized area is weakened and complicated.

• Journal of Korean Society of Forest Science
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• v.98 no.2
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• pp.189-196
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• 2009

This study was conducted to evaluate spatial distribution pattern and spatial association of crowns (${\geq}10m$ of height) and saplings (<10 m of height and ${\geq}2cm$ of DBH) for four major tree species (Pinus koraiensis, Abies nephrolepis, Acer mono, and Tilia amurensis) in the mixed broadleaved-Korean pine forest of Xiaoxing'an Mts. Vegetation data were collected in the 9 ha permanent sample plot, and the analysis adopted the point pattern analysis method. Main results are as follows; 1) crowns and saplings of major species showed clumped distribution pattern in small scale, became random distribution as the scale was increased. 2) Saplings of Pinus koraiensis performed poor regeneration under the crowns of Pinus koraiensis and Abies nephrolepis; Saplings of Abies nephrolepis did good regeneration under the crowns of Pinus koraiensis and Abies nephrolepis; and crowns of Acer mono and Tilia amurensis had little effect on the distribution of saplings of Pinus koraiensis and Abies nephrolepis. Saplings of Acer mono and Tilia amurensis made good regeneration under the crowns of Pinus koraiensis and Tilia amurensis; and the crowns of Acer mono and Abies nephrolepis had little effect on the distribution of saplings of Acer mono.

• Spatial Information Research
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• v.6 no.1
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• pp.11-23
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• 1998

Map generalization functions to visualize the spatial data or to change their scale by changing the level of details of data. Until recently, the studies on map generalization have concentrated more on line features than on point features. However, point features are one of the essential components of digital maps and cannnot be ignored because of the great amount of information they carry. This study, therefore, aimed to find out a detailed procedure of point features' generalization. Particularly, this work chose the distribution pattern of point features as the most important factor in the point generalization in investigating the geometric characteristics of source data. First, it attempted to find out the characteristics of distribution pattern of point features through quadrat analysis with Grieg-Smith method and nearest-neighbour analysis. It then generalized point features through the generalization threshold which did not alter the characteristics of distribution pattern and the removal of redudant point feautres. Therefore, the generalization procedure of point features provided by this work maintained the geometric characteristics as much as possible.

• Journal of Korean Society of Forest Science
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• v.99 no.5
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• pp.720-725
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• 2010

On the basis of vegetation data in the 9.12 ha (380 m ${\times}$ 240 m) permanent sample plot of the spruce-fir valley forest in Liangshui National Reserve of Xiaoxing'an Mountains, the study was conducted to evaluate spatial distribution pattern and spatial association by using point pattern analysis for living and dead trees of Larix gmelini by DBH size class. The number of L. gmelini were counted as 59 living stems/ha (6.42 $m^2$/ha of basal area) and 34 dead stems/ha (2.86 $m^2$/ha of basal area). The distributional curve of diameter class exhibited bimodal shape. The analysis of spatial distribution patterns of all living larch stems noted the clumped distribution on the whole. The size of larch aggregates of dead stems was decreased as diameter class was increased. The distribution of dead stems became gradually randomized with decreased clumped size as the scale increased. Living stems and dead stems of the larch had positive spatial association at most of scales, illustrating that the occurrence of mortality of the larch tree was closely related to the distribution pattern of living larch trees.

• Journal of Advanced Marine Engineering and Technology
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• v.30 no.4
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• pp.474-482
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• 2006

Generally almost all fatigue crack growth is affected by mode I. For this reason a study on mode I has concentrated in the field of fracture mechanics. However the fatigue crack initiation and growth in machines and structures usually occur in mixed mode loading. If there is any relationship between the cause of fracture in mixed mode loading and fracture surface, fracture surface pattern will be the main mean explaining reasons of fatigue fracture and obtaining further information about fracture process. In this paper low point shear-fatigue test with Aluminum alloy hi 5083-O is carried out from this prospect and then the mixed mode distribution of fracture surface is examined from the result after identifying the generation of fatigue crack surface pattern. It was found from the experimental results that the fatigue crack surface pattern and the fatigue crack shear direction are remarkably consistent. Furthermore It is possible that the analysis of distribution of mixed mode through the fatigue crack surface pattern.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2006.06a
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• pp.43-44
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• 2006

Generally almost all fatigue crack growth is affected by model. For this reason a study on model has concentrated in the field of fracture mechanics. However the fatigue crack initiation and growth in machines and structures usually occur in mixed mode loading. If there is any relationship between the cause of fracture in mixed mode loading and fracture surface, fracture surface pattern will be the main mean explaining reasons of fatigue fracture and obtaining further information about fracture process. In this paper four point shear-fatigue test with Aluminum alloy Al 5083-O is carried out from this prospect and then the mixed mode distribution of fracture surface is examined from the result after identifying the generation of fatigue crack surface pattern. It was found from the experimental results that the fatigue crack surface pattern and the fatigue crack shear direction are remarkably consistent. Furthermore It is possible that the analysis of distribution of mixed mode through the fatigue crack surface pattern.

• Journal of Korean Society of Forest Science
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• v.99 no.3
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• pp.259-266
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• 2010

Forest fire occurrence in Korea is highly related to human activities and its spatial distribution shows a strong spatial dependency with cluster pattern. In this study, we analyzed spatial distribution pattern of forest fire with point pattern analysis considering spatial dependency. Distributional pattern was derived from Ripley's K-function according to causes and distances. Spatially clustered intensity was found out using Kernel intensity estimation. As a result, forest fires in Korea show clustered pattern, although the degrees of clustering for each cause are different. Furthermore, spatial clustering pattern can be classified into two groups in terms of degrees of clustering and distance. The first group shows the national-wide cluster pattern related to the human activity near forests, such as human-induced accidental fire in mountain and field incineration. Another group shows localized cluster pattern which is clustered within a short distance. It is associated with the smoker fire, arson, accidental by children. The range of localized clustering was 30 km. Beyond of this range, the patterns of forest fire became random distribution gradually. Kernel intensity analysis showed that the latter group, which have localized cluster pattern, was occurred in near Seoul with high densed population.

• Journal of the Economic Geographical Society of Korea
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• v.10 no.3
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• pp.319-331
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• 2007

Nowadays, urbanized area expands its boundary, and distribution of urbanized area is gradually transformed into more complicated pattern. In Korea, SMA(Seoul Metropolitan Area) has outstanding urbanized area since 1960. But it is ambiguous whether urban distribution is clustered or dispersed. That is to say, it is difficult to understand spatial distribution pattern of urbanized area, although urbanized area has grown gradually. This study aims to show the way in which expansions of urbanized area impact on spatial distribution pattern of urbanized area. We use GIS analysis based on raster dataset, quadrat analysis, and nearest neighbor analysis to know distribution pattern of urbanized area in time-series urban growth. Experiments show that cohesion of SMA's urbanized area had increased to the early 1980s, but has decreased from the middle 1980s. Also, urban growth of SMA has been characterized not by spillover growth but by leapfrogging growth and road-influenced growth since the middle 1980s.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.12
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• pp.36-47
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• 1995

The main purpose of this paper is to determine a new focal point and field distribution due to the shape deformation of reflector antenna by numerical method such as geometrical optics and the aperture field method. It is shown the 4 types deformations to be added into original shape of parabola antenna and offset antenna: linear, quadratic, cubic and hybrid distortion. These results can be applied to deformed reflector antenna in order to fit a focal point and radiation pattern.

• The KSFM Journal of Fluid Machinery
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• v.13 no.3
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• pp.37-42
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• 2010

This study investigated on details of flow characteristics of a multi-blade fan for domestic ventilation. Experiments and analysis were carried out to describe on flow pattern with variations of cut-off angle near the scroll housing throat, which were performed by PIV measurement for the flow field and by total pressure probes. The stagnation point at cut-off region of the fan moves to the exit of the scroll housing as the cut-off angle increases. The movement of stagnation point and the variation of throat area of the scroll housing influence to the distribution of velocity magnitude at the exit of the fan. Furthermore, a large distortion of the velocity distribution at the scroll exit causes to increase mixing loss along the flow path.