• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.1611-1615
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• 2006

The purpose of this study is to simulate the riverbed profile changes downstream of Daecheong re-regulation dam from 1988 to 2001, to evaluate the model's applicability and to predict a long-term riverbed-level variation between 2002 and 2017. As a result of simulation 14 sediment transport equations provided by GSTAR-1D, it was found that Acker's & White formula was the most stable relatively. The interval used to calculate its stability was 7 days for bankful discharge$(1,000m^2/s)$, 3 days for daily maximum flow$(4,273m^2/s)$, 1 day for hourly maximum flow$(7,605m^2/s)$ and minimum flow$(8.5m^2/s)$. The simulation results of river bed changes were evaluated and compared to its measure data from 1988 to 2001. It was showed that there was the degradation for a section between Daecheong re-regulation dam and Maepo water stage gage station due to bed-material, and the degradation for a reach between Maepo and Gongju water stage gage station due to massive aggregate collection. Also, as a result of simulating the river profile change for 2002 to 2017, it was predicted that the section between Daecheong re-regulation dam and Geumnam Bridge would remain as the present profile and the reach between Maepo and Gongju water stage gage station would have some degradations in several parts, which would be stable as a whole unless it was due to artificial river profile change.

• Journal of Korea Water Resources Association
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• v.38 no.7 s.156
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• pp.545-554
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• 2005

The detailed interdisciplinary surveys were conducted on the pattern of habitat use of dominant fishes during the spawning and adult stage. The hydraulic parameters of the depth and velocity, discharge, substrate cover streams, and distribution of fish in the Yeonggang, WiCheon, HoeCheon, GeochangwiCheon, CheongdoCheon, DanjangCheon (the Nakdong River Basin) were measured. The Habitat Suitability Criteria was developed for the two fish species (Zacco Platypus and Zacco Temmincki) and life stages(spawning and adult), habitat conditions (depth, velocity and covet). The Physical Habitat Simulation of the Instream Flow Incremental Methodology was applied to calculate for optimal flow and the ecological flow recommendation was proposed by choosing the largest one in the optimal flow. The ecological flow recommendation was $5.0\;m^3/s{\sim}10.0\;m^3/s$ (e.g., $6.5\;m^3/s$ in the NaeseongCheon). Also, the ecological flow recommendations were compared with the existing ecological flow and flow duration analysis.

• Journal of Digital Convergence
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• v.15 no.10
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• pp.173-182
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• 2017

On the tourism purchasing stage, this study is focused on analyzing the relationship among tourism omnichannel selecting factor, satisfaction and purchasing intention considering the moderator effects of tourism experience and perceived risk. Based upon antecedent studies and literature about tourism omnichannel, We presented the study model and hypotheses. For the accurate analysis, we did field survey with 400 respondents. The results are as follows. First, the positive relationship are found between channel selecting factors during purchasing and tourism omnichannel satisfaction. Secondly there is a positive relationship between tourism omni-channel satisfaction and tourism purchasing intention. Thirdly tourism experience is proved as a positive moderating effect between channel selecting factors during purchasing and tourism omni-channel satisfaction. But the moderating effect of perceived risk is negative between them.

• Horticultural Science & Technology
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• v.31 no.4
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• pp.503-511
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• 2013

The purpose of this study was to evaluate temperature reduction and heat budget of extensive modular green roof planted with Sedum sarmentosum and Zoysia japonica. Plant height and green coverage were measured as plant growth. Temperature, net radiation and evapotranspiration of concrete surface, green roof surface, in-soil and bottom were measured from August 2 to August 3, 2012 (48 hours). On 3 P.M., August 3, 2012, when air temperature was the highest ($34.6^{\circ}C$), concrete surface temperature was highest ($57.5^{\circ}C$), followed by surface temperature of Sedum sarmentosum ($40.1^{\circ}C$) and Zoysia japonica ($38.3^{\circ}C$), which proved temperature reduction effect of green roof. Temperature reduction effect of green roof was also shown inside green roof soil, and bottom of green roof. It was found that Zoysia japonica was more effective in temperature reduction than Sedum sarmentosum. Compared with the case of concrete surface, the highest temperature of green roof surface was observed approximately 2 hours delayed. Plant species, temperature and soil moisture were found to have impact on surface temperature reduction. Plant species, air temperature, soil moisture and green roof surface temperature were found to have impact on temperature reduction in green roof bottom. As results of heat budget analysis, sensible heat was highest on concrete surface and was found to be reduced by green roof. Latent heat flux of Zoysia japonica was higher than that of Sedum sarmentosum, which implied that Zoysia japonica was more effective to improve thermal environment for green roof than Sedum sarmentosum.

• Journal of the Korean Geotechnical Society
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• v.19 no.4
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• pp.167-178
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• 2003

Damage and overbreak of the remaining rock induced by blasting can not be avoided during tunnel construction which may result in either short-term or long-term tunnel instability. Therefore, in this paper, a methodology to take into account the effect of blast-induced damage in tunnel stability assessment is proposed. Dynamic numerical analysis was executed to evaluate damage and overbreak of the remaining rock for the most common blasting pattern in road tunnel. Rock damage was quantified by utilizing the damage variable factor which is adopted proposed in continuum damage mechanics. The damaged rock stiffness and the damaged failure criteria are used to consider the effect of rock damage in tunnel stability analysis. The damaged geological strength index of the damaged rock was newly proposed from the relationship between deformation modulus and geological strength index. Also the Hoek-Brown failure criteria of the damaged rock was obtained using the damaged geological strength index. Analysing the tunnel stability with the consideration of the blast-induced damage of remaining rock, it was found that the extend of plastic zone and deformation increased compared to the undamaged rock. Therefore the short-term or long-term tunnel stability will be threatened when the rock damage from blasting is ignored in the tunnel stability analysis.

• Fire Science and Engineering
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• v.27 no.3
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• pp.30-37
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• 2013

The ultimate purpose of the present study is to secure a effective method for foam liquid discharge when the mixing ratio deviates from the permissible range due to a decrease in the bypass flow rate resulting from a decrease in the cross sectional area of the foam liquid piping ranging from the branching header of one foam proportioner to the branching headers of multiple branching foam fire-extinguishing systems in the region for fire extinguishing and then to the standpipe at the lower part of the storage tank when a fire occurred in a combustible tank. To this end, the cause of mixing ratio variations following changes in the flow rates of existing foam fire extinguishing systems was analyzed, methods for compensation for constant mixing ratios were investigated, and it was proved that metering orifice replacements that could expand the cross sectional area of the stock solution inhaling piping was the most effective way for the improvement of form fire extinguishing systems' mixing ratios through foam proportioner venturi, foam chamber orifice, and metering orifice replacement experiments.

• Korean Journal of Medicinal Crop Science
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• v.26 no.5
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• pp.382-390
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• 2018

Background: The plant Aster koraiensis has long been used as an ingredient in folk medicine. It has been reported that Aster koraiensis extract (AKE) prevents the progression of diabetes-induced retinopathy and nephropathy. However, although these beneficial effects of AKE on diabetes complications have been identified, the antidiabetic effects of AKE have not yet been completely investigated and quantified. In the present study, the glucose-lowering and antioxidant effects of aqueous and ethanolic AKEs were evaluated. Methods and Results: The glucose-lowering effects of aqueous and ethanolic (30%-, 50%-, and 80%-ethanol) AKEs were investigated via ${\alpha}$-glucosidase inhibitory assays. The mode of inhibition by AKEs on ${\alpha}$-glucosidase was identified through kinetic analysis. The total antioxidant capacity of each of the 4 AKEs was evaluated by assessing their conversion rate of $Cu^{2+}$ to $Cu^+$. The content of chlorogenic acid and 3,5-di-O-caffeoylquinic acid, the bioactive compounds in AKE, in each extract were analyzed by high performance liquid chromatography (HPLC). The AKEs showed potent ${\alpha}$-glucosidase inhibitory activity with mixed inhibition mode, and significant antioxidant capacity. Conclusions: These results of this study suggested that the AKEs tested had ${\alpha}$-glucosidase inhibitory and antioxidant effects. Among the extracts, the 80% ethanol extract showed the most significant ${\alpha}$-glucosidase inhibitory activity, with a half maximal inhibitory concentration ($IC_{50}$ value) of $1.65{\pm}0.36mg/m{\ell}$ and a half maximal effective concentration ($EC_{50}$ value) for its antioxidant activity of $0.42{\pm}0.10mg/m{\ell}$. It can therefore be used as a source of therapeutic agents to treat diabetes patients.

• Fire Science and Engineering
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• v.29 no.2
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• pp.84-91
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• 2015

The purpose of this study is to suggest the reasonable model of the caliber in suction nozzle, the pressure of suction nozzle, and the flow rate about foam system of line proportioner type using in the pumpcar. To test this, the experimental study was accomplished on the ground of the standards for the Performance Certification and Product Inspection of Foam Fire-extinguishing Chemical Mixing Machine. Aqueous Film Forming Foam in 3% and pipe type air foam nozzle with line proportioner FE 40 type were used. Test result showed that the pressure of suction nozzle within the limits between 0.25 MPa and 0.35 MPa was appropriate when the caliber in suction nozzle is 4 mm. Also, the pressure of suction nozzle within the limits between 0.45 MPa and 0.60 MPa was appropriate in the higher pressure than 4 mm when the caliber in suction nozzle is 5 mm.

• Journal of the Korean Wood Science and Technology
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• v.42 no.3
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• pp.327-338
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• 2014

Relationship between growth rate and wood quality was investigated by physical and mechanical properties with Quercus rubra (24 years old) from five different origin of apricot. In greenwood moisture content, sapwood had higher moisture content than heartwood, and there was difference among different origin of apricot. There were different specific gravity of wood among different origin of apricot. Compared with higher growth rate with higher specific gravity in sapwood, opposite trend was observed in heartwood. There were difference in shrinkage based on origin of apricot, and higher growth rate wood had higher shrinkage and T/R ratio. Compression Young's modulus, bending strength, bending Young's modulus, and compact strength was difference among different origin of apricot. Higher growth rate wood had higher tensile strength, and also there was difference amont different origin of apricot. In hardness, 3 different directions had all difference among different origin of apricot, and higher growth rate wood showed higher hardness than others. Based on overall physical and/or mechanical properties and growth rate, apricot from Bancroft was best quality in current.

• 재활복지
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• v.17 no.4
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• pp.197-219
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• 2013

The aim of this study was to examine self-efficacy and work ethic on the moderating effect of retraining program for personal assistants to influence job environments and job satisfaction. The data were obtained from 330 personal assistants working at the Personal Assistance Association of Gyeonggi-do. The data were analyzed using the Structural Equation Modeling with relative effect analysis. The result of this study showed that self-efficacy and work ethics should have an impact job environments and job environments should have a positive impact job satisfaction. The retraining program for personal assistants showed a moderating effect on the relationship between work ethics and job environments. However, the findings did not support the moderator effect on the retraining program for personal assistants in the relationship between self-efficacy and job environments. Using these findings, social work administration agency, in particular, can be guided in terms of human resource management under social work administration.