• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.6 no.2
• /
• pp.42-52
• /
• 1988

The main object of this study is to prove the effectiveness of Landsat data in detecting the stressed areas in forest by extracting these areas. And also to choose the effective bands for this type of survey and to reduce the effect of shadow in forest to improve the accuracy of classification are the other objects. In this study Landsat-5 TM data is used and image processing techniques such as spatial filtering and ratio are taken to reduce the effect of shadow and to improve the classification accuracy. As a result following conclusions are obtained. First, Landsat TM data is useful to detect the stressed areas in forest. Second, when detecting the stressed area, band 4 and 5 are the most effective. Third, spatial filtering and ratio are useful to reudce the effect of shadow and improve the classification accuracy. Especially, ratio has great effect on improving the classification accuracy between forest and other areas.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.11 no.2
• /
• pp.125-133
• /
• 2007

External confinement by CFS (Carbon Fiber Sheet) is a very effective retrofit method for the reinforced concrete columns subject to either static or seismic loads. For the reliable and cost-effective design of CFS, an accurate stress-strain curve is required for CFS-confined concrete. In this paper, uniaxial compression test on short RC column with circular section was performed. To evaluate the effect of confinement on the stress-strain relationship of CFS-confined concrete, CFS area ratio, spiral area ratio, and concrete compressive strength are considered as the test variables. Experiment results indicate that CFS jacketing significantly enhances strength and ductility of concrete. In addition, the CFS-jacketed specimens with the spiral steel show the lower load increasement ratio than those without the spiral steel.

• Journal of Wetlands Research
• /
• v.25 no.2
• /
• pp.121-131
• /
• 2023

This study examines the possible problem in the rainfall-runoff analysis process using the VIC (Variable Infiltration Capacity) model caused by using the effective soil depth instead of the soil depth. The parameters of the model are determined as follows. First, parameters that can be determined using available numerical information are fixed. For parameters related to direct runoff and base runoff, the recommended values of the VIC model are applied. In the case of soil depth, four cases are considered: (1) the effective soil depth is applied as the soil depth, (2) 1.5 times of the effective soil depth is applied as the soil depth by reflecting the vertical structure of the soil layer, (3) 1.25 times of the effective soil depth, and (4) 2.0 times of the effective soil depth as alternative soil depths. This study simulates the rainfall-runoff for the period from 1983 to 2020 targeting the Chungju Dam and Soyang River Dam basins of the Han River system. As a result of the study, it is confirmed that when the effective soil depth is applied instead of the soil depth, direct runoff and baseflow have opposite effects, and direct runoff increases by more than 3% while base runoff decreases by the same scale. In addition, the most influential factor in the estimation of the effective soil depth in the Chungju Dam and Soyanggang Dam basins is found to be the proportion of rock outcrop area. The difference between the direct runoff ratio and the base runoff ratio in the two basins is conformed significantly different due to the influence of the rock outcrop area.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.10 no.4
• /
• pp.83-94
• /
• 2007

Test application of revegetation measure was made on the roadside slope damaged by Gimcheon-Eomo national road improvement project in a bid to prevent the soil from being washed out as well as to restore the ecological environment, and the survey for assessing the effect of slope revegetation measures was conducted, beginning Sep 7 through Sep 20, 2006. In the wake of comprehensive reviewing and evaluating the surrounding topographic environment, physical and chemical characteristics of soil, germination of revegetation plants, analysis of bio mass, covering ratio and the plants appeared, revegetation measure C was found to have been most effective and desirable for further application in the area. Viewing the specific applicability by the area, revegetation measure C and C-1 appeared to be appropriate for blasting rock slope and ripping rock slope as they are efficient in preventing the slope from being washed out and in early revegetating. And revegetation measure B deemed to be effective to blasting rock slope or ripping rock slope as an alternative. And for cut slope, vegetation measure C-2 was judged to be more effective than measure D or E, while measure C-3 would be appropriateto embankment slope.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.23 no.2
• /
• pp.61-69
• /
• 1981

The paddies in the hillsides in Gonggeun-myeon, Hoingseong-gun, Kangweon-do keep a steep slope and run in and out. A land consolidation in such an area, therefore, will require high ratio of land loss and a large amount of earth moving if it follows the existing design criteria to separate drainage and irrigation ditches in a scheme. Due to the consequent decrease in construction cost, the project has not been envisaged. in order to secure the introduction of small-medium size farm machineries into the paddies, farm plots were planned to be straight and drainage with taking care of topography. Findings from the comparison of methodologies are as follows. 1. In places with a solpe of more than 1/30, a reduction in earth moving can be expected with parallel plots to the contours. 2, For the sake of effective using of farm machineries, it is thought that a plot should be running straight parallel to the contours and the ratio of length and width of a plot be more than six. 3. In places with a slop of more than 1/10, a reduction in earth moving and a effective introduction of farm-machineries can he expected with straight parllel plots to the contours. But it is undesirable to introduce a scheme in this places because of the difficulties in acreage computation and farmers' hesitation. 4. The system with a canal for both irrigation and drainage is highly effective to decrease the ratio of land loss as well as construction cost. 5. Parallel plots to the contours and a canal for both irrigation and drainage are highly effective in the decrease in construct cost. 6. To avoid the subdivision of a cooperation in farming is desirable of a plots, has more than two owners.

• Proceedings of the SAREK Conference
• /
• 2006.06a
• /
• pp.1075-1080
• /
• 2006

Purpose of this study is proposal of estimating method about window thermal performance that based on KS F 2278 'Test method of thermal resistance for windows and doors' due to material composition of PVC frame window. First step of this study is research of present state about material composition of PVC frame window. Second is selection of main effective elements about window thermal resistance. For example, composition of Glazing, Frame area ratio of total window area, frame width, opening type, area of heat transfer and so on. Third is multiple regression analysis about thermal performance of PVC frame window due to main effective elements. It produces equations of multiple regression analysis due to opening type. Case of sliding window is $Y=0.149+0.034X_g+0.248X_{far}$, 4track sliding is $Y=0.584+0.175X_g+1.355X_{far}-0.008X_{fw}$, Tilt & Turn window is $Y=-0.161+0.076X_g+0.576X_{far}+0.0008X_{fw}$.

• Steel and Composite Structures
• /
• v.48 no.4
• /
• pp.385-403
• /
• 2023

To avoid premature damage to the connection joints of a conventional precast concrete shear wall, a new precast concrete shear wall system (NPSW) based on a plastic damage relocation design concept was proposed. Five specimens, including one monolithic cast-in-place concrete shear wall (MSW) as a reference and four NPSWs with different connection details (TNPSW, INPSW, HNPSW, and TNPSW-N), were designed and tested by lateral low-cyclic loading. To accurately assess the damage relocation effect and quantify the damage and deformation, digital image correlation (DIC) and conventional data acquisition methods were used in the experimental program. The concrete cracking development, crack area ratio, maximum residual crack width, curvature of the wall panel, lateral displacement, and deformed shapes of the specimens were investigated. The results showed that the plastic damage relocation design concept was effective; the initial cracking occurred at the bottom of the precast shear wall panel (middle section) of the proposed NPSWs. The test results indicated that the crack area ratio and the maximum residual crack width of the NPSWs were less than those of the MSW. The NPSWs were deformed continuously; significant distortions did not occur in their connection regions, demonstrating the merits of the proposed NPSWs. The curvatures of the middle sections of the NPSWs were lower than that of the MSW after a drift ratio of 0.5%. Among the NPSWs, HNPSW demonstrated the best performance, as its crack area ratio, concrete damage, and maximum residual crack width were the lowest.

• Korean Journal of Materials Research
• /
• v.22 no.6
• /
• pp.321-327
• /
• 2012

The production of functional activated carbon materials starting from inexpensive natural precursors using environmentally friendly and economically effective processes has attracted much attention in the areas of material science and technology. In particular, the use of plant biomass to produce functional carbonaceous materials has attracted a great deal of attention in various aspects. In this study the preparation of activated carbon has been attempted from rice husks via a chemical activation-assisted microwave system. The rice husks were milled via attrition milling with aluminum balls, and then carbonized under purified $N_2$. The operational parameters including the activation agents, chemical impregnation weight ratio of the calcined rice husk to KOH (1:1, 1:2 and 1:4), microwave power heating within irradiation time (3-5 min), and the second activation process on the adsorption capability were investigated. Experimental results were investigated using XRD, FT-IR, and SEM. It was found that the BET surface area of activated carbons irrespective of the activation agent resulted in surface area. The activated carbons prepared by microwave heating with an activation process have higher surface area and larger average pore size than those prepared by activation without microwave heating when the ratio with KOH solution was the same. The activation time using microwave heating and the chemical impregnation ratio with KOH solution were varied to determine the optimal method for obtaining high surface area activated carbon (1505 $m^2$/g).

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.2
• /
• pp.1490-1499
• /
• 2015

The purpose of this study is to improve Biotope Area Ratio(BAR) systems used in the various fields. Recently, there has been increasing demand in urban agriculture as well as more residents cultivating farms on a small scale. However, there are few measures in terms of architecture and urban planning to respond to this trend. In this sense, this research is effective as it can respond to these demands by using BAR systems. Yet, the environmental indexes are not enough since BAR systems only take account of vegetation. Therefore, this study proposes an alternative way that includes the capacity factor of the plant growth by expanding the existing BAR systems. Thus, the study analyzes the complementary possibility of BAR systems, including elements of daylight, planting interval, area and soil depth with existing BAR elements.

• Journal of Environmental Science International
• /
• v.17 no.5
• /
• pp.485-491
• /
• 2008

The present study examined the relation between land cover condition and temperature in various types of urban green spaces. The diagram of temperature distribution showed that high-temperature zones are formed around paved areas, and low temperature zone around planted areas and grassy areas. Even in planted areas where low-temperature zones were formed, temperature was different according to hierarchical structure. That is, temperature was relatively low in areas covered with arbor + sub-arbor. With regard to land cover ratio, the increase of planted areas and grassy areas had an effect on the fall of temperature and the effect was higher in order of planted areas and grassy areas. On the contrary, paved areas and bare areas had an effect on the rise of temperature. According to the results of factor analysis, in case of the highest temperature, planted area and grassy area were put together into a factor lowering temperature, paved area and temperature into a factor raising temperature, and bare area alone into a factor of low significance. In case of the lowest temperature, grassy area and bare area were put together into a factor, and the validity of the factor analysis was proved by the analysis of urban heat islands. An increase in the number of trees by height was effective in lowering temperature, and the effect was high in order to arbor and sub-arbor, and the source of coldness in planted area was tall trees.