• Journal of Korea Water Resources Association
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• v.48 no.6
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• pp.425-438
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• 2015

The objective of this study was to evaluate simulation of agricultural water supply considering yearly variation of irrigation efficiency. The water supply data of the Idong reservoir from 2001 through 2009 was collected and used for this study. Total 6 parameters including irrigation efficiency (Es), drainage outlet height, and infiltration, were used for sensitivity analysis, calibration, and validation. Among the parameters, the Es appeared to be the most sensitivity parameter. The Es was calibrated on a yearly basis considering sensitivity and time-varying characteristic, while other parameters were set to fixed values. The statistics of percent bias (PBLAS), Nash-Sutcliffe efficiency (NSE), and root means square error to the standard deviation of measured data (RSR) for a monthly step were 2.7%, 0.93, and 0.26 for the calibration, and 3.9%, 0.89, and 0.32 for the validation, correspondently. The results showed a good agreement with the observations. This implies that the modeling only with appropriate parameter values, apart from modeling approaches, can simulate the real supply operation reasonably well. However, the simulations with uncalibrated parameters from previous studies produced poor results. Thus, it is important to use calibrated values, and especially, we suggest the Es's yearly calibration for simulating agricultural water supply.

• Korean Journal of Microbiology
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• v.44 no.4
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• pp.317-325
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• 2008

Recently there are difficulties in management of golf courses because of an ever increasing demand for golf as a leisure sports. Hence natural minerals as an amendment could be applied to improve and manage the physicochemical properties of the golf course soils in an environment-friendly way. In this study, quartz porphyry, which has been shown to be a good soil amendment for crop production, was tested for its effect on physicochemical properties of the golf course soil, growth of creeping bentgrass (Agrostis stolonifera) and changes of soil microbial communities in the soil. In general, amendment of 20% quartz porphyry into the soil turned out to be most effective in enhancing a proper growth of the grass leaves and roots. DGGE profile data showed that eubacterial species richness was also the highest at this level of the mineral treatment in which Actinobacteria and ${\alpha}$-Proteobacteria were the dominant phyla. This appeared to be attributed to a low level of soluble organic matter content and decreased concentration of cations such as $Ca^{2+}$, $Mg^{2+}$, and $K^+$.

• Korean Journal of Construction Engineering and Management
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• v.15 no.4
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• pp.86-94
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• 2014

Since the late 1990s, mixed-use apartment, armed with high qualities and large scales with a high ratio of TFA(Total Floor Area) have been continuously provided accommodating exclusive community facilities along with high-tech securities, not to mention excellent skyline view. However, especially in mid-small cities, there have been only a few supplies. As a result, none of the mixed-use housing provided by high-end brands has ever been built in non-metropolitan area. But constructors couldn't plan the projects which aims to build the mixed-use apartment in local city, because they couldn't get the basic data or advanced research for feasibility analysis. Therefore, to suggest the useful price for mixed-use apartment supply project of local city, the PSM(Price Sensitivity Method) widely used for determining the price preferences as a market research tools has been applied. As analysis results, the estimated price of mixed-use apartment is 10.8% higher than general apartment, and mixed-use apartment has lower price sensitivity than general apartment. As price determinants, the age, education level and family size influence on UTP in significant level. It is expected that these research findings can be applied for establishing the solid marketing strategy of mixed-use apartment development project in local city.

• The Journal of Engineering Geology
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• v.16 no.4 s.50
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• pp.393-402
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• 2006

The contamination characteristics of BTEX and TPH components in silty soils with the oil leakage event from point source were studied. The over ratios of three soil pollution standard for TPH component were $1.5{\sim}1.7$ times higher than that of BTEX component. The mean and maximum values of BTEX and TPH components with sample points were B-zone > A-zone > C-zone, and the highest concentrations were measured at $1{\sim}2m$ depth below surface. BTEX and TPH components were increased with linear distance in zone within 120 m and 80 m from point source. For the zone more than 120 m, BTEX and TPH concentrations were under soil pollution standard. The cutoff values of indicator kriging using BTEX and TPH components were defined as confirmative limit, warn- ing limit and counterplan limit. The variograms of indicator-transformed data were selected linear model. The contamination ranges of BTEX and TPH components using confirmative limit and warning limit were estimated similar, but the contamination range of those using counterplan limit was much reduced. The maximum contamination probabilities were estimated by probability maps usinB confirmative limit, warning limit and counterplan limit. The maximum contamination probabilities with three soil pollution standard were estimated 26%, 26% and 13% for BTEX component, and 44%, 38% and 26% for TPH component.

• Environmental Engineering Research
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• v.13 no.3
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• pp.125-130
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• 2008

Free ammonia ($NH_3$-N) inhibition of nitrite-oxidizing bacteria (NOB) has been widely studied for partial nitrification (or nitrite accumulation) and denitrification via nitrite ($NO_2^-$-N) as a low-cost treatment of ammonium containing wastewater. The literature on $NH_3$-N inhibition of NOB, however, shows disagreement about the threshold $NH_3$-N concentration and its degree of inhibition. In order to clarify the confusion, a simple and cheap respirometric method was devised to investigate the effect of free ammonia inhibition of NOB. Sludge samples from an autotrophic nitrifying reactor were exposed to various $NH_3$-N concentrations to measure the maximum specific nitrite oxidation rate ($\hat{K}_{NO}$) using a respirometer. NOB biomass was estimated from the yield values in the literature. Free ammonia inhibition of nitrite oxidizing bacteria was reversible and the specific nitrite oxidation rate ($K_{NO}$) decreased from 0.141 to 0.116, 0.100, 0.097 and 0.081 mg $NO_2^-$-N/mg NOB h, respectively, as the $NH_3$-N concentration increased from 0.0 to 1.0, 4.1, 9.7 and 22.9 mg/L. A nonlinear regression based on the noncompetitive inhibition mode gave an estimate of the Inhibition concentration ($K_I$) of free ammonia to be 21.3 mg $NH_3$-N/L. Previous studies gave $\hat{K}_{NO}$ of Nitrobacter and Nitrospira as 0.120 and 0.032 mg/mg VSS h. The free ammonia concentration which inhibits Nitrobacter was $30{\sim}50\;mg$ $NH_3$-N/L and Nitrospira was inhibited at $0.04{\sim}0.08\;mg$ $NH_3$-N/L. The results support the fact that Nitrobacter is the dominant NOB in the reactor. The variations in the reported values of free ammonia inhibition may be due to the different species of nitrite oxidizers present in the reactors. The respirometric method provides rapid and reliable analysis of the behavior and community of the nitrite oxidizing bacteria.

• Journal of the Korean Institute of Landscape Architecture
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• v.42 no.6
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• pp.111-123
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• 2014

The city square is an important public open space for people. Being used for various activities, such as community gatherings, open markets, concerts, political rallies, and other events, many types of city squares are represented in a city. Nevertheless, most city squares are planned uniformly, lacking consideration for visitor behavior and use satisfaction. The study investigated the design factors and subcomponents influencing user satisfaction with different types of city squares. This study focused on the general city square in Seoul, including the grand public place (i.e. Gwanghwamun Square) and the neighborhood park (i.e. Geumbit Square). The data were analyzed using factor analysis, linear regression and fuzzy theory. The results of the study are as follows: first, five design factors of satisfaction with city squares are identified (Amenity, Usability, Spatial components, Culture, and Comfortableness). Second, Amenity, Comfortableness, and spatial components significantly affect user satisfaction with Gwanghwamun in that order. On the other hand, in Geumbit Square, Comfortableness, Amenity, Usability and Spatial components affect user satisfaction in a significant way, in that order. Third, cleanliness, a subcomponent of amenity, was ranked highest using the fuzzy theory function for satisfaction with Gwanghwamun Square. Otherwise, the prevalence of plants was ranked the highest on the Geumbit Square survey. The study compared design factors influencing satisfaction in the public grand place and the neighborhood park. The results have implications for designing and planning city squares to the satisfaction of their visitors.

• Journal of Korea Water Resources Association
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• v.53 no.8
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• pp.617-626
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• 2020

This study investigates changes of bifurcation discharge ratio, flow velocity distributions and characteristics of separation zone due to variation of bifurcation angle by using TELEMAC-2D model. When the bifurcation angle is reduced from 90° to 45° without changing the boundary conditions, the bifurcation discharge ratio increased by 1.5 times from 0.523 to 0.785 because of increasing the radius of curvatures, the inertia force of the downstream flow, and the pressure gradient by the downstream boundary conditions. The bifurcation discharge ratio increases non-linearly whenever the bifurcation angle decreases by 15° intervals from 90° to 45° in flow with the upstream Froude number of 0.45 to 0.74. In flow with a maximum Froude number of 0.74, the rate of increase for bifurcation discharge ratio is 31.1% and the minimum value. When the Froude number is 0.58, the bifurcation discharge ratio is 0.7 or less, and the maximum rate of increase for that ratio is 53.5%. As the upstream Froude number decreases less than 0.58, the bifurcation discharge ratio exceeds 0.7, and the rate of increase decreases. When the upstream Froude number is 0.4 higher, the dimensionless width and length changing ratio of the separation zone are about 2.56 and 5.5 times higher than in 0.4 or less.

• Journal of agriculture & life science
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• v.45 no.6
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• pp.237-249
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• 2011

The purpose of this study was to monitor the streamflow of rural streams for investigating the status of stream depletion located downstream of irrigation reservoir. Bonghyun and Hi reservoirs area, located in Gyeongnam, Gosung-gun, Hi-myeon, were selected for study watersheds and streams. Streamflow monitoring were conducted 6 times during the paddy growing season of 2010 from May to October. Streamflow was measured for 18 stations downstream from two reservoirs with the interval of 300m to 500m, The amount of streamflow were highly dependent on the antecedent precipitation and irrigation amount. In most observation stations, streamflow was depleted when precipitation and irrigation were not provided. Pumping from stream for irrigation and water supply for factory and irrigation return flow were also factors on streamflow. Continuous monitoring for rural streams located in downstream of reservoirs are required to quantify the status of streamflow depletion and determine the amount of environmental flows.

• Ecology and Resilient Infrastructure
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• v.7 no.4
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• pp.284-293
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• 2020

We present a quantitative survey of the carbon storage and absorption capacity of tree species in the vegetation conservation and ecological restoration areas of Bulamsan urban nature park in Nowon-gu, Seoul. The density of the sawtooth oak (Quercus acutissima) community in the ecological conservation area is approximately 30 individuals/225 ㎡, while a further 20 species, such as Japanese snowbell (Styrax obassia), galcham oak (Quercus aliena), Asian Sweetleaf (Symplocos chinensis f. pilosa), East Asian ash (Fraxinus rhynchophylla), and Korean rhododendron (Rhododendron mucronulatum) are sparsely distributed. In contrast, the ecological restoration sites typically comprised Mongolian oak (Quercus mongolica), jolcham oak (Quercus serrata), and East Asian ash (Fraxinus rhynchophylla) plantations, with planting densities of 8.3, 7.7, and 14.3 individuals/25 ㎡ , respectively. Approximately 10 species, including Amur maple (Acer tataricum subsp. ginnala), Korean mountain ash (Sorbus alnifolia), Japanese spice bush (Lindera obtusiloba), and Korean rhododendron (Rhododendron mucronulatum) were identified in the ecologically restored area. The total amounts of carbon stored by the trees in the vegetation conservation and ecological restoration sites are 250.77 and 19.3 t C ha-1, respectively, and the total annual carbon uptakes are 10.28 and 2.33 t C ha-1 yr-1, respectively. The survey results are expected to provide important basic data for monitoring the carbon absorption capacity and carbon balance of green areas in the city.

• Journal of Korean Society of Rural Planning
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• v.27 no.1
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• pp.57-70
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• 2021

The degree of benefits of living services related to the quality of life can solve the depopulation problem, and it is necessary to be able to quantitatively analyze problems related to the quality of life in rural areas in order to cope with the rural depopulation. The purpose of this study was to develop the assessment model of a village-level rural living service that reflects the regional characteristics of rural villages to evaluate the level of rural living services for response rural depopulation. Based on the review of previous related studies, the evaluation index was composed of seven sectors of education, health, welfare, culture, environment, safety, and convenience, and the assessment model of a rural living service was established. This model was evaluated through a sample survey of 90 villages in Nonsan-si, Seongju-gun, and Pyeongchang-gun. As a result of the rural life services evaluation by Si and Gun, Seongju-gun, which is affected by nearby large cities, has the largest variation by village level and is assessed at a lower level overall than other Si and Gun. As a result of the rural life services evaluation by 7 sectors, in the case of health and welfare, low scores were shown in the assessment model, but the level of residents' satisfaction was mid-level. In particular, in the case of Seongju-gun, there were significant differences in the assessment model and the survey results of the level of residents' satisfaction in the health and welfare sectors due to the influence of nearby large cities. As a result of analyzing the number of villages corresponding to the top 30% and the bottom 30% of the evaluation results for each sector, it was analyzed that the villages with the highest evaluation results in Pyeongchang-gun in both the assessment model and the level of residents' satisfaction. It implies that quantitative analysis of data based index and accessibility as well as level satisfaction of residents are necessary.