• Journal of the Korean Geotechnical Society
• /
• v.25 no.10
• /
• pp.111-122
• /
• 2009

Dissolution of some of geo-materials may yield the loss of the soil strength and the settlement of earth structures. The goal of this study is to monitor the several physical behaviors of soluble mixtures during dissolution. Sand-salt mixtures are used to monitor the meso to macro response including the settlements and shear waves. The mixtures of photoelastic and ice disks are used to monitor micro to meso behavior of soluble mixture including the void ratio, force chain, coordination number and horizontal force changes. In the sand-salt mixtures, shear waves are measured by using bender elements in conventional oedometer cells. In the photoelastic disk - ice disk mixtures, micro to meso response are measured by digital images and load cells. The shear wave velocity decreases at the initial stage of the dissolution, and then increases and approaches to asymptotic value. The larger dissoluble particle and the more random packing produces the severe horizontal fore change. After dissolution, the void increases and the coordination number decreases. This study demonstrates that the particle level behavior such as the changes of the force chain, void ratio, and coordination number affects the global behavior such as the change of the shear wave velocity and horizontal force of the system.

• Journal of Environmental Policy
• /
• v.4 no.1
• /
• pp.21-38
• /
• 2005

In this study, a model for analyzing the spatial effect of large dam reservoirs on local hydrometeorology was developed, and then actually applied to the Seomjingang Dam, Soyanggang Dam, Andong Dam, and Chungju Dam. The application included the analysis of land use using the satellite images to derive the change in albedo before and after the dam construction. Summarizing the modeling procedure and its application results are as follows. (1) The change in albedo was found to be closely related with the size of the dam, also the spatial limit of albedo change were estimated to be 10-20km for the Seomjingang Dam, 40km for the Soyanggang Dam, 20-30km for the Andong Dam, and 50km for the Chungju Dam. (2) The change in the coefficient of recycle (ratio of internal supply of moisture to the total available moisture) was found to be big within the narrow boundary of the. dam, but become smaller as the boundary becomes larger. (3) The correlation between the albedo and. coefficient of recycle was found high. Thus, it could be concluded that the change in land use due to dam construction has much effect on the moisture circulation structure. (4) The spatial range of hydrometeorogic effect was compared with the water surface area of dam reservoir. The result showed that the spatial range sensitively increased up to $50km^2$ of water surface area.

• Spatial Information Research
• /
• v.19 no.2
• /
• pp.9-18
• /
• 2011

The purpose of this research is to evaluate an accurate biotope area ratio model with efficiency and convenience of database management through promoting sustainable development to provide people amenities in a new town. In particular, the biotope area ratio is used not only in the environment impact assessment but Green building certification criteria. But now there is no any index map of biotope. So it is very hard to implement with data for supplement results. In this research, we suggest the model of integrated attributable information. The evaluation of biotope area ratio is to include a basic land use planning map and a building coverage area which is a wall of greening surface and roof. In case of non building coverage area, the evaluation of biotope area ratio is to include water space, artificial ground, natural ground and pervious gap-pave. A weighted value on the spatial information is combined into the information. And then the merged one is given a land use planning information in a block. In the weighted value on the space type information, it is possible to in its circumstances. Therefore, it can be substituted a correspondence of numerical change for various values elastically in this model.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.40 no.2
• /
• pp.15-23
• /
• 2012

This study was accomplished by analyzing the change of land cover pattern in high-rise buildings in Korea. For this study, we selected 15 locations of high-rise buildings. The ratio of average building coverage and paved area was 79.7%, and both green and water area were low, relatively. The biotope area factor of the site showed low percentage by 15.90% due to the underground space development. As a result of correlation analysis between the time of construction and land-cover type, building coverage has been decreased according to the stream of time. However, biotope area factor has been increased And, the paved area has m correlation. It was identified that reducing paved area is effective to enhance the ecological functions of a high-rise building outdoor.

• Journal of Korea Water Resources Association
• /
• v.37 no.2
• /
• pp.109-119
• /
• 2004

This research is an analysis of the water vapor transport change Into the continent due to the global warming effect with the general circulation models. Water vapor transport change from ocean to land increases through the year due to CO2 doubling effect. In Eurasia, it indicates an increase about 170∼350${\times}$06 Mt/day the whole year. In Africa, it shows an decrease every month except November, especially there is the maximum decrease about -350${\times}$106 Mt/day during August-September. In other continents, excluding Eurasia and Africa, the change of water vapor transport vary with the month below $\pm$8.0${\times}$106 Mt/day with the unsystematic patterns. In Eurasia, the change of water vapor transport increases as a whole, but it decrease in desert areas which occupy a high area-ratio. Therefore, except desert areas, the amount of the growth in water vapor transport change concentrate on Asian monsoon area. As a result of monsoon strengthening, available water will grow considerably at the asian monsoon areas.

• Proceedings of the KSRS Conference
• /
• 1998.09a
• /
• pp.192-197
• /
• 1998

This paper demonstrates that it is feasible to evaluate forest degradation and to detect deforestation in the 8156$km^2$ study area affected by expand farming using vegetation indices derived from Landsat TM data. The NDVI-growing stock relation was applied on th Landsat TM data and a 3 second grid DEM, whose coverages could improve the assessment of forest degradation and also estimate the rate of change of forest cover area depending on elevation intervals. The strength of the relationship between the ratio of the greenness and brightness indices and forest degradation conditions would have been more interesting in the deforested areas which were converted to crop farming land.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.31 no.1
• /
• pp.45-57
• /
• 1989

The hydrologic model FESHM was introduced and its applicability was investigated in an attempt to analyze the rainfall-runoff relationships of urban small watersheds and to hereafter predict the envi-ronmental changes. Basic data on rainfall, water level, geomorphological characterisitics and land use were obtained from Yeonwha stream watershed located in Chonju-si Dukjin-dong. WL-5 for simulation o subshed WS# 1(136.7 ha) with urban district and WL-1 for total watershed WS#5 (278.78 ha) we'e selected as gaging points. The main results gained through applications were summarized as follows. 1. Direct runoff ratio caalculated from a simple separation method for WS#5 WS# 1 was 2O~39%, 38~62%, respectively. 2. Simulations for the runoff estimation were carried out for each watershed using 5 rainfall events, the simulation errors had the range of 2~ 30%, O~ 63% and O 120 minutes for the runoff volume, peak flow and peak time, respectively. 3. The effect of landuse change by urbanization was tested to WS# 1, runoff volume before development was estimated as from tenth to twentieth against after development.

• Journal of Korean Society of Water and Wastewater
• /
• v.28 no.6
• /
• pp.635-645
• /
• 2014

The changes of rainfall pattern and impervious covers have increased disaster risks in urbanized areas. Impervious covers such as roads and building roofs have been dramatically increased. So, it is falling the ability safety of flood defense equipments to exist. Runoff coefficient means ratio of runoff by whole rainfall which is able to directly contribute at surface runoff during rainfall event. The application of accurate runoff coefficients is very important in sewer pipelines design. This study has been performed to estimate runoff characteristics change which are applicable to the process of sewer pipelines design or various public facilities design. It has used the SHER model, a long-term runoff model, to analyze the impact of a rising impervious covers on runoff coefficient change. It thus analyzed the long-term runoff to analyze rainfall basins extraction. Consequently, it was found that impervious surfaces could be a important factor for urban flood control. We could suggest the application of accurate runoff coefficients in accordance to the land Impervious covers. The average increase rates of runoff coefficients increased 0.011 for 1% increase of impervious covers. By having the application of the results, we could improve plans for facilities design.

• 한국태양에너지학회:학술대회논문집
• /
• 2009.04a
• /
• pp.180-183
• /
• 2009

In this study, Urban Climate Simulation was performed by 3-Dimensional Urban Canopy Model. The characteristics of urban climate was analyzed combining artificial land coverage, building size, heat production from the air conditioning and topographic conditions as physical variables which affects urban climate characteristics. The results are as follows. (1)The aspects of the urban climatal change is derived to be related to the combination of the building coverage ratio, building height and shading area. (2)Whole heat generation was influenced by the convective sensible heat at the lower building height and by the artificial heat generation at the higher one over 20-story building influence to some extent of the building coverage ratio. The effect of the altitude is not more considerable than the other variables as below $1^{\circ}C$ of the air temperature.

• Journal of Korean Society of Rural Planning
• /
• v.10 no.1 s.22
• /
• pp.19-26
• /
• 2004

In this paper, forestry area change effect on the soil erosion in Asan lake watershed was estimated. Temporal variations of land use in the study watershed were analyzed from Landsat-5 TM remote sensing images. Geographic Information System (GIS) combined with Universal Soil Loss Equation (USLE) was used to estimate the soil erosion of Asan lake watershed. Spatial data for each USLE factors was obtained from the Landsat-5 TM remote sensing images and 1/25,000 scale digital contour maps. Sediment yield to Asan lake was estimated by sediment delivery ratio and sediment accumulation in lake was estimated by trap efficiency. The estimation methods were validated for sediment accumulation in Asan lake. From the hydrographic survey from 1974 to 2003 for Asan lake, sediment accumulation was measured. The estimated accumulation sediment of 303,569ton/yr showed similar value with observed of 295,888ton/yr. From the validated estimation methods, the increasing amount of soil erosion when 1% of forest area in Asan lake watershed decreases was calculated from 12.91 to 1482.05ton/yr.