Cho Byung , Jin Yu Chan

DOI: JKWST Vol.46(No.7) 3-12, 2004

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The need to predict the rate of soil erosion, both under existing conditions and those expected to occur following soil conservation practice, has been led to the development of various models. In this study Morgan model especially developed for field-sized areas on hill slopes was applied to assess the rate of soil erosion using RS/GIS environment in the Dukchun river basin, one of two tributaries flowing into Jinyang lake. In order to run the model, land cover mapping was made by the supervised classification method with Landsat TM satellite image data, the digital soil map was generated from scanning and screen digitizing from the hard copy of soil maps, digital elevation map (DEM) in order to generate the slope map was made by the digital map (DM) produced by National Geographic Information Institute (NGII). Almost all model parameters were generated to the multiple raster data layers, and the map calculation was made by the raster based GIS software, IL WIS which was developed by ITC, the Netherlands. Model results show that the annual soil loss rates are 5.2, 18.4, 30.3, 58.2 and 60.2 ton/ha/year in forest, paddy fields, built-up area, bare soil, and upland fields respectively. The estimated rates seemed to be high under the normal climatic conditions because of exaggerated land slopes due to DEM generation using 100 m contour interval. However, the results were worthwhile to estimate soil loss in hilly areas and the more precise result could be expected when the more accurate slope data is available.

Hong Seong Min , Jung In Kyun , Park Geun Ae , Kim Seong Joon

DOI: JKWST Vol.46(No.7) 15-21, 2004

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This study is to present a standardized agricultural land use classification scheme at various spatial resolution (from 1 m to 30 m) of satellite images including Landsat TM, KOMPSAT-1 EOC, ASTER VNIR and IKONOS panchromatic (PAN) and multi-spectral (MS) images. The satellite images were interpreted especially for identifying agricultural land use, crop types, agricultural facilities and structures of 18 items. It was found that there is a threshold spatial resolution between 4 m and 6.6 m to identify the full items. Thus it is suggested that IKONOS fusion image (MS enhanced by PAN) is required to produce land use map for agricultural purpose.

Kim Dae Sik

DOI: JKWST Vol.46(No.7) 23-32, 2004

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A spatial simulation model for rural and urban sprawl phenomena was developed with GIS and cellular automata techniques. The model finds out built-up areas invading toward rural areas required for development of existing urban area. Probability of land use change for optimizing the development area was determined using a land suitability analysis method interfaced with GIS methods, based on several criteria in terms of geographic and accessibility factors such as slope of land and distance from city center. Weighting values of the criteria were quantified by an analytic hierarchy process method. For model applicability test, the parameters of criteria were calibrated based on the changes in time series land use data of the test city for 1986, 1996, and 2000, which were classified by remote sensing techniques. Simulated and observed areas in land use maps for city shape of 1996 showed good similarities with each other through a morphology verification method. The model enabled us to evaluate the spatial expansion phenomena of cities considering boundary conditions, and also to simulate land use planning for rural areas in urban fringe.

Kim Kee Sung , Han Jin Hee , Kim Moon Ki , Nam Sang Woon

DOI: JKWST Vol.46(No.7) 35-44, 2004

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In this study, a ventilation model was developed to determine a ventilation rate for the balance of heat, moisture and CO₂ in a mushroom house. Internal and external temperature, relative humidity and CO₂ concentration were measured and used to validate the ventilation model. The effects of various environmental factors on physiological responses of mushroom were also investigated. The verified model was simulated under the observed ventilation rates with a difference of 0.001~0.065㎥ㆍs^-1 (relative error of 0.3~18.9%) when external temperature varied 22.5 to 24.8℃ and average ventilation rates was 0.35㎥ㆍs^-1. The optimal conditions for mushroom growth (internal temperature 22℃, relative humidity 80%, CO₂ concentration 1,000 ppm) were used for the model application with external temperature, relative humidity and CO₂ concentration of 27.5~33.5℃, 60%, and 355 ppm, respectively. Thermal balance was a important factor for an optimum ventilation up to the external temperature of 32℃, while CO₂ concentration balance was more important over 32℃. This suggests that humidification for moisture balance is required to maintain temperature and CO₂ concentration at an optimal level by ventilation in a mushroom house.

Park Phil Woo , Sung Chan Yong

DOI: JKWST Vol.46(No.7) 47-53, 2004

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Permeable polymer concrete can be applied to roads, sidewalks, river embankments, drain pipes, conduits, retaining walls, yards, parking lots, plazas, interlocking blocks, etc. This study was to explore a possibility of using blast furnace slag powder and stone dust of industrial by-products as fillers for Eco-permeable polymer concrete. Different mix proportions were tried to find an optimum mix proportion of the Eco-permeable polymer concrete. The tests were carried out at 20±1℃ and 60±2% relative humidity. At 7 days of curing, unit weight, coefficient of permeability, dynamic modulus of elasticity, compressive, flexural and splitting tensile strengths ranged between 1,821~1955 ㎏/㎥, 0.056~0.081 ㎝/s, 114×10²~ 157×10² MPa, 17.6~24.7 MPa, 5.98~7.94 MPa and 3.43~4.70 MPa, respectively. It was concluded that the blast furnace slag powder and stone dust can be used in the Eco-permeable polymer concrete.

Kim Young Ik , Sung Chan Yong

DOI: JKWST Vol.46(No.7) 55-67, 2004

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In this paper, the flowability, strengths, impact resistance and sulfuric acid resistance of steel fiber reinforced high performance concrete (SFHPC) for the steel fiber content and fly ash and blast furnace slag as admixtures were presented. For evaluating flowability particularly, tests of slump flow, box-type passing ability and L-type filling ability were performed. The slump flow of SFHPC was some decreased with increase of the steel fiber content. At the box-type passing ability, the difference of box height of SFHPC is greatly increased with increasing the fiber content. The L-type filling ability of SFHPC was not excellent above 0.75% of the steel fiber content. Also, the compressive strength of SFHPC was decreased with increase of the steel fiber content, but the flexural strength of SFHPC was much higher than that of the concrete without the steel fiber. At the impact resistance, drop number of SFHPC for reaching final fracture was increased with increase of the fiber content. Also, the drop number for reaching initial fracture of lmm was increased with increase of the fiber content. At the sulfuric acid resistance, 4-week weight change of SFHPC with the steel fiber was almost similarity that of HPC without the steel fiber and was in the range of 73.6 to 81.5.

Noh Jae Kyoung

DOI: JKWST Vol.46(No.7) 71-80, 2004

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A system for estimating daily paddy irrigation water requirements was developed to simulate daily stream flows that reflect various upstream and downstream return flows from river basin. Evapotranspiration in paddy fields was estimated using the modified Penman equation. Daily irrigation water requirements of paddy fields were calculated by multiplying the paddy area and the daily decrease in ponding depth. The system was constructed almost completely using images, grids, etc. in Visual Basic 6.0. The developed model was verified in the Damyang dam, and was used to estimate daily paddy irrigation water requirements at 12 small watersheds in Geum river basin for 20 years, from 1983 to 2002, covering paddy field areas of 3,332~26,422 ha. The results on the runoff analysis on the inflow to the Daecheong multi-purpose dam with various return flows were satisfactory. They were reasonable compared to the scenario where return flows were not considered.