• Journal of Korean Tunnelling and Underground Space Association
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• v.8 no.3
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• pp.249-257
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• 2006

The spatial distribution of design parameters greatly affects tunnel behavior during and after construction, as well as in the long-term temporal responses. However, the tunnel design parameters commonly used in numerical modeling tend to be representative or average values of global-scale properties. Furthermore, the uncertainty and spatial variation of the design parameters increase as the tunnel scale increases. Consequently, the probability of failure also increases. In order to achieve structural stability in large-section tunnels, the design framework must take into consideration the quantitative effect of design parameter variations on tunnel behavior. Therefore, this paper suggests a statistical approach to numerical modeling to explore the effect of spatially distributed design parameters in a circular tunnel. Also, the effect of spatial variation in the lining strength is studied in this paper. The numerical results suggest that the deformation around the tunnel increases with an increase in the variation of the design parameters.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.9
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• pp.1109-1116
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• 2013

This study aims to investigate the spatial randomness of fatigue crack growth rate for the friction stir welded (FSWed) 7075-T651 aluminum alloy joints. Our previous fatigue crack growth test data are adopted in this investigation. To clearly understand the spatial randomness of fatigue crack growth rate, fatigue crack growth tests were conducted under constant stress intensity factor range (SIFR) control testing. The experimental data were analyzed for two different materials-base metal (BM) and weld metal (WM)-to investigate the effects of spatial randomness of fatigue crack growth rate and material properties, the friction stir welded (FSWed) 7075-T651 aluminum alloy joints, namely weld metal (WM) and base metal (BM). The results showed that the variability, as evaluated by Weibull statistical analysis, of the WM is higher than that of the BM.

• Journal of Korean Society for Geospatial Information Science
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• v.21 no.2
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• pp.85-92
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• 2013

This study determined the spatial distribution characteristics of carbon dioxide in Northeast Asia, connecting land coverage and vegetation index that have influence on concentration and distribution of carbon dioxide measured by GOSAT with GIS spatial analysis method. The results visibly showed that the spatial distribution of carbon dioxide had different patterns in dependent on the present status of land use in its surrounding area. Such high concentration of carbon dioxide was formed in developed sites like cities while forest areas showed low concentration of it. We also found that there were relatively high negative(-) correlations between carbon dioxide and vegetation, in statistically significant level. It is expected to be used as a basic data for establishing measures to reduce greenhouse gas in the future.

• Spatial Information Research
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• v.9 no.2
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• pp.185-206
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• 2001

Cellular Automata(CA) have been investigated and utilized as a theoretical framework and/or methodology for analyzing and simulating the properties and behaviors of many complex systems in various physical science and engineering field. Due to the conceptual elegance and effectiveness of implementing spatio-temporal dynamic models and the compatibility with raster GISs, recently a variety of modeling works using both CA and GIS have been published in GIS fields Most of spatial dynamic models introduced in previous research, however, were very limited and furthermore integrated CA-GIS system for practical modeling purpose are not developed yet. This study aims to develop an integrated CA-GIS system in which a CA simulator is used as an analytical engine for GIS providing a multipurpose spatial dynamic modeling functionalities. This integrated CA-GIS system is anticipated radically enhancing the current lacking dynamic modeling functionalities of GIS and being utilized as an powerful and effective tool for practical spatial dynamic modeling research.

• Journal of Korean Association for Spatial Structures
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• v.22 no.3
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• pp.25-32
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• 2022

In this paper, the instability of the domed spatial truss structure using wood and the characteristics of the buckling critical load were studied. Hexagonal space truss was adopted as the model to be analyzed, and two boundary conditions were considered. In the first case, the deformation of the inclined member is only considered, and in the second case, the deformation of the horizontal member is also considered. The materials of the model adopted in this paper are steel and timbers, and the considered timbers are spruce, pine, and larch. Here, the inelastic properties of the material are not considered. The instability of the target structure was observed through non-linear incremental analysis, and the buckling critical load was calculated through the singularities and eigenvalues of the tangential stiffness matrix at each incremental step. From the analysis results, in the example of the boundary condition considering only the inclined member, the critical buckling load was lower when using timber than when using steel, and the critical buckling load was determined according to the modulus of elasticity of timber. In the case of boundary conditions considering the effect of the horizontal member, using a mixture of steel and timber case had a lower buckling critical load than the steel case. But, the result showed that it was more effective in structural stability than only timber was used.

• Journal of the Korean Geotechnical Society
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• v.26 no.10
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• pp.39-47
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• 2010

In order to investigate the effect of variation characteristics of compression index on the spatial distribution of consolidation settlement, this study presents the estimation methods of the distribution of consolidation settlement and compares the estimated settlements. When the variation of compression index is considerable, the ordinary cokriging is more reliable in estimating the compression index than ordinary kriging because smoothing effect of ordinary cokriging is smaller than that of ordinary kriging. The spatial distribution of consolidation settlement estimated by considering both the variation of compression index and void ratio (CASE-1) is different from that estimated by using the mean value of all soil properties (CASE-2). The settlement of CASE-1 shows the larger variation at short distances rather than that of CASE-2. Whereas the spatial settlement distribution of CASE-1 is affected by the spatial distributions of compression index as well as the thickness of consolidation layer, that of CASE-2 is significantly influenced by the distribution of consolidation layer thickness.

• Korean Journal of Ecology and Environment
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• v.36 no.4 s.105
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• pp.403-412
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• 2003

Temporal and spatial variations of size-structured phytoplankton (chlorophyll a) were investigated over an annual cycle (February-October, 2003) to elucidate phytoplankton dynamics in the Juam Reservoir, Chonnam. Physical properties were also measured to investigate the relationship between the properties and temporal and spatial variations of size structured phytoplankton using simple linear regression. Phytoplankton (chlorophyll a) were grouped into three size classes: micro-size(> 20 ${\mu}m$), nano-size (3-20 ${\mu}m$) and pico-size (< 3 ${\mu}m$) in this study. Physical properties included water temperature, light attenuation coefficients, PAR (photosynthetically active radiation) and turbidity. Maximum chlorophyll a was observed in April, 2003 in the lower region whereas a peak of chlorophyll a developed in October, 2003 in the upper region. Large cell-sized phytoplankton (micro-size class)were dominant in the events of the chlorophyll a peaks. Potential mechanisms in the physical properties affecting the size-structured phytoplankton dynamics in the Juam Reservoir were discussed.

• Korean Journal of Soil Science and Fertilizer
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• v.22 no.4
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• pp.257-264
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• 1989

In order to study spatial variability of soil chemical properties across the land-partitioned boundary on Hwadong silt clay loam soil (Fine clayey, mixed, mesic family of Aquic Hapludalfs) in the experimental fie ld of the wheat and Barley Research Institute in Suwon, all measured data were analyzed by means of kriging, fractile diagram, smooth frequency distribution, and autocorrelation. Sampling for soil chemical property analysis was made at 225 intersections of 15x 15 grid with 10m interval from three soil depths (0-10cm, 25-35cm, 50-60cm) in the seven patitioned fields. 1. The coefficient of variance (CV) of various chemical properties varied from 5.4 to 72.7%. Soil pH was classified into the low variation group with CV smaller than 10%, while the other chemical properties belonged to the medium variation group with C.V. between 10 and 100% 2. The approximate number of soil samples for the determination of various chemical properties with error smaller than 10% were two for pH, ten for CEC, 15 for exchangeable Ca, 32 for total nitrogen content, 39 for exchangeable Mg, 40 for exchangeable K, 61 for exchangeable Na, 82 for organic matter content, 212 for available phosphate,. 3. Smooth frequency distribution and fractile diagram showed that available phosphate was in log-normal distribution while others were in normal distribution. 4. Serial correlation analysis revaled that the soil chemical properties had spatial dependence between two nearest neighbouring grid points. Autocorrelation analysis of chemcial properties measured between the serial grid points in the direction of south to north following land-partitioned boundary showed that the zone of influence showing stationarity ranged from 20 to 50m. In the direction of east to west accross land-partitioned boundary, the autocorrelogram of many chemical properies showed peaks with the periodic interval of 30m, which were similar to the partitioned land width. This reveals that the land-partitioned boundary causes soil variability.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.5
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• pp.351-360
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• 2015

Human influence on soil formation has dramatically increased with human civilization and industry development. Increase of anthropogenic soils induced researches on the anthropogenic soils; classification, chemical and physical characteristics of anthropogenic soils and plant growth from anthropogenic soils. However there have been no comprehensive analyses on soil pore or physical properties of anthropogenic soils from 3 dimensional images in Korea. The objectives of this study were to characterize physical properties of anthropogenic paddy field soils by depth and to find differences between natural and anthropogenic paddy field soils. Soil samples were taken from two anthropogenic and natural paddy field soils; anthropogenic (A_c) and natural (N_c) paddy soils with topsoil of coarse texture and anthropogenic (A_f) and natural (N_f) paddy soils with topsoil of fine texture. The anthropogenic paddy fields were reestablished during the Arable Land Remodeling Project from 2011 to 2012 and continued rice farming after the project. Natural paddy fields had no artificial changes or disturbance in soil layers up to 1m depth. Samples were taken at three different depths and analyzed for routine physical properties (texture, bulk density, etc.) and pore properties with computer tomography (CT) scans. The CT scan provided 3 dimensional images at resolution of 0.01 mm to calculate pore radius size, length, and tortuosity of soil pores. Fractal and configuration entropy analyses were applied to quantify pore structure and analyze spatial distribution of pores within soil images. The results of measured physical properties showed no clear trend or significant differences across depths or sites from all samples, except the properties from topsoils. The results of pore morphology and spatial distribution analyses provided detailed information of pores affected by human influences. Pore length and size showed significant decrease in anthropogenic soils. Especially, pores of A_c had great decrease in length compared to N_c. Fractal and entropy analyses showed clear changes of pore distributions across sites. The topsoil layer of A_c showed more degradation of pore structure than that of N_c, while pores of A_f topsoil did not show significant degradation compared with those of N_f. These results concluded that anthropogenic soils with coarse texture may have more effects on pore properties than ones with fine texture. The reestablished paddy fields may need more fundamental remediation to improve physical conditions.

• Journal of Environmental Science International
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• v.12 no.8
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• pp.835-840
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• 2003

Many various kinds of tourism resources have been distributed along the Nakdong river basin. Previous researches have focused mainly on environmental studies, including water quality control, industrial use of water, biodiversity, etc, with little research done in the field of tourism studies. Central to this study, therefore, is the identification and analysis, from the perspective of cultural tourism, of the area's distribution and characteristics of cultural properties registered by the MOCT. Review of related literature reveals : 1) spatial range bound with the jurisdiction of the river basin like DREO and NRBEO ; 2) analytical subjects limited to cultural properties designated by the three different administrative units of government, city and province. Along with the DREO's predominance over the NRBEO in the total number of cultural properties, the result finds that two cities, Andong and Gyeongju of Gyeongbuk are assigned ownership of most of the cultural properties under the jurisdiction of DREO, while Gyeongnam that of most of the ones under the NRBEO. However, those findings suggest the simple number of cultural properties with no significant level of importance and rarity value reflected. Therefore, future studies need to develop quantified modelling keeping cultural variables in mind and create cultural indices of the competitiveness of the local governments.