• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.144-144
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• 2022

Identifying waterbody from remote sensing images, namely water detection, helps understand continuous redistribution of terrestrial water storage and accompanying hydrological processes. It also allows us to estimate available surface water resources and help effective water management. For this problem, NDWI (Normalized Difference Water Index) and MNDWI (Modified Normalized Difference Water Index) are widely used. Although remote sensing indexes can highlight remote sensing image in the water, the noise and the spatial information of the remote sensing image are difficult to be considered, so the accuracy is difficult to be compared with the visual interpretation (the most accurate method, but it requires a lot of labor, which makes it difficult to apply). In this study, we attempt to improve existing NDWI and MNDWI to better water detection. We establish waterbody database of South Korea first and then used it for assessing waterbody indices.

• Journal of The Geomorphological Association of Korea
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• v.20 no.3
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• pp.15-25
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• 2013

The purpose of this study is to identify the environment of optimal location of the dwelling (hereafter referred as dwelling site) in the Neolithic Age found in Unseo-dong relics group, Yeongjong-do, Incheon from the geographical and geomorphological perspectives. For this purpose, micro-landform, altitude, gradient, distance from the river of water available for use and the difference between the highest altitude and lowest altitude of river bed of water available for use based on change of dwelling site over periods were analyzed targeting ground surface of hills where individual dwelling sites (a total of 68 sites) discovered in investigation area so far. As a result, it was shown that the Upper sideslope were selected as the primary dwelling location standard in investigation area where the Neolithic people lived upon selecting the dwelling site (or settlement). In addition, the ground surface of dwelling site had the altitude of 21-31m and slope of $5-10^{\circ}$ (gentle slope) as the secondary and it had distance of 514-549m from the river of water available for use and difference of 11-23m between the highest altitude and lowest altitude of river bed of water available for use. Thus, it was shown that the space to get water relatively easy from two places at the same time was the secondary dwelling location standard.

• Korean Journal of Soil Science and Fertilizer
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• v.21 no.1
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• pp.21-29
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• 1988

A laboratory experiment was conducted to evaluate the phosphorus status and define the relationship between composition of phosphorus forms and available phosphorus with 149 phosphorus accumulated soil samples. Distribution percentage of inorganic, organic and available phosphorous to total phosphorus were 68.9 (Saloid-p 2.7, Al-p 26.4, Fe-p 27.6, Ca-p 12.2%), 6.7 and 26.0%, respectively. In the relationship between available phosphorus and inorganic phosphorus in soil, Al-p, Saloid-P, and Ca-P showed significant correlation with available phosphorus which did not showed significant one with Fe-p. Multiple liner regression equation between available and inoganic phosphorus abtained as follow, $Av.P=81.694+0.858Sa-p^{***}+0.648Al-p^{***}+0.091Ca-p^{**}(R=0.826^{***})$ and contribution rates of Saloid-p, Al-p, and Ca-p to available phosphorus were 26.1, 65.2, and 8.7%, respectively. Relationship between available and water soluble phosphorus, water soluble phosphorus and $0.01M-CaCl_2-p$ were highly significant, respectively, and soil solution P extracted with $0.01M-CaCl_2$ for 30 minutes was selected as one of usable diagnostic techniques for soil P status.

• Journal of Korean Society of Water and Wastewater
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• v.19 no.1
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• pp.8-15
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• 2005

Field measurement data on water leakage are not readily available and it causes inaccurate assessment of water demand and poor supply planning. In this study, the procedure for leakage detection and unaccounted water calculation is proposed and applied to a city. The city has suffered from the significant amount of leak water and the financial loss as a result. Measurements were made for pressure and flow at 18 locations before and after the repair. Repair of the leakage increased pressure up to $2.0kgf/cm^2$ and saved 17.1% of water supply from distribution reservoirs. Monetary value of annual water savings for the entire city amounts to 1 billion won. It is believed that leakage detection and data analysis conducted in this study will contribute to the change of current practice and to the establishment of better water supply management system.

• Journal of Korean Society on Water Environment
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• v.24 no.2
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• pp.221-229
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• 2008

This study revised a model for hydrologically analyzing rainwater harvesting facilities considering their rainfall-runoff properties and the data available. This model has only a few parameters, which can be estimated with rather poor measurements available. The model has a non-linear module for rainfall loss, and the remaining rainfall excess (effective rainfall) is assumed to be inflow to the storage tank. This model has been applied for the rainwater harvesting facilities in Seoul National University, Korea Institute of Construction Technology, and the Daejon World Cup Stadium. As a result, the runoff coefficients estimated were about 0.9 for the building roof as a rainwater collecting surface and about 0.18 for the playground. This result is coincident with that for designing the rainwater harvesting facilities to show the accuracy of model and the simulation results.

• Magazine of the Korean Society of Agricultural Engineers
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• v.44 no.5
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• pp.54-66
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• 2002

A grid-based hydrological model, CELTHYM, capable of estimating base flow and surface runoff using only readily available data, was used to assess hydrologic impacts caused by land use change on Little Eagle Creek (LEC) in Central Indiana. Using time periods when land use data are available, the model was calibrated with two years of observed stream flow data, 1983-1984, and verified by comparison of model predictions with observed stream flow data for 1972-1974 and 1990-1992. Stream flow data were separated into direct runoff and base flow using HYSEP (USGS) to estimate the impacts of urbanization on each hydrologic component. Analysis of the ratio between direct runoff and total runoff from simulation results, and the change in these ratios with land use change, shows that the ratio of direct runoff increases proportionally with increasing urban area. The ratio of direct runoff also varies with annual rainfall, with dry year ratios larger than those for wet years shows that urbanization might be more harmful during dry years than abundant rainfall years in terms of water yield and water quality management.

• Korean Journal of Soil Science and Fertilizer
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• v.6 no.1
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• pp.61-65
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• 1973

Analysis of data in the Official Soil Series Description showed the dominant texture of upland soils is SiL, of which available water range is 21.1% highest among textures. Analyses of data in the N, P, K Trials on Barley in 1964/65-1968/69, and N, P, K and Soil Improvement Trials on upland Crops in 1961-1969 were made to relate fertilizer response to the amount of rainfalls during the growing season. Correlation between nitrogen response and the amount of rainfalls was observed but not between P and K and the amount of rainfalls. Some of physical properties were discussed to seek feasible means for increasing available water.

• Wind and Structures
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• v.12 no.6
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• pp.519-540
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• 2009

This paper presents the results of a study into experimental and numerical methods for the identification of bridge deck flutter derivatives. Nine bridge deck sections were investigated in a water tunnel in order to create an empirical reference set for numerical investigations. The same sections, plus a wide range of further sections, were studied numerically using a commercially available CFD code. The experimental and numerical results were compared with respect to accuracy, sensitivity, and practical suitability. Furthermore, the relevance of the effective angle of attack, the possible assessment of non-critical vibrations, and the formulation of lateral vibrations were studied. Selected results are presented in this paper. The full set of raw data is available online to provide researchers and engineers with a comprehensive benchmarking tool.

• Membrane and Water Treatment
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• v.11 no.1
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• pp.31-39
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• 2020

Anaerobic membrane bioreactor (AnMBR) treatment has been widely studied in recent years because of the potential for production of bio-energy from wastewater and energy-positive operation of wastewater treatment plants. Several AnMBR systems, including those that incorporate ceramic membranes, take advantage of enhanced water permeability and low membrane fouling potentials. Given that differences in the ceramic membranes may influence the results of AnMBR studies, relevant details are discussed in this review, which focuses on the profiles of common ceramic membranes used in AnMBR, treatment and filtration performances of different anaerobic ceramic membrane bioreactors (AnCMBRs), and the membrane fouling mitigation methods available for effective AnCMBRs operation. The aim of this review is to provide a comprehensive summary of AnCMBR performance, feed wastewater characteristics, operating conditions, and the methods available for effective fouling mitigation.

• YAKHAK HOEJI
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• v.45 no.5
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• pp.437-441
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• 2001

The quasi-drugs including nonwoven fabric and gauze were sterilized using ethylene oxide (EO) gas. Residual EO in the quasi-drugs was extracted with water (20 mL of water for 1 g of sample) for 24h at 37$^{\circ}C$. Residual EO was determined using GC. The optimal analytical conditions were as follows : column, Carbowax 20M (1.D. 0.2 mm); mobile phase, helium with 30 mL/min; oven temperature 57$^{\circ}C$, injector temperature 18$0^{\circ}C$, detector temperature 20$0^{\circ}C$. The detection limit for EO was 0.10$\mu$g/mL. When the residual EO extracted from nonwoven fabric and gauze was determined, it took more than 9h to get the lower level than 25 ppm which is the limit value of FDA guideline. When the EO residues, ethylene chlorohydrine (ECH) and ethylene glycol (EG) in the 7 commercially available quasi-drugs were determined, no residual EO, ECH, EG were found from the seven commercially available quasi-drugs analyzed by this method.