• Proceedings of the Materials Research Society of Korea Conference
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• 1998.08a
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• pp.47.4-47
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• 1998

• Proceedings of the KAIS Fall Conference
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• 2000.04a
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• pp.8-8
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• 2000

• Journal of Korean Association for Spatial Structures
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• v.21 no.2
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• pp.18-25
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• 2021

• Journal of Korean Association for Spatial Structures
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• v.20 no.3
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• pp.15-20
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• 2020

• Journal of Korea Water Resources Association
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• v.45 no.4
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• pp.349-360
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• 2012

A horizontally curvilinear non-hydrostatic free surface model that was applicable to three-dimensional viscous flows was developed. The proposed model employed a top-layer equation to close kinematic free-surface boundary condition, and an isotropic k-${\varepsilon}$ model to close turbulence viscosity in the Reynolds averaged Navier-Stokes equation. The model solved the governing equations with a fractional step method, which solved intermediate velocities in the advection-diffusion step, and corrects these provisional velocities by accounting for source terms including pressure gradient and gravity acceleration. Numerical applications were implemented to the wind-driven currents in a two-dimensional closed basin, the flow in a steep-sided trench, and the flow in a strongly-curved channel accounting for secondary current by the centrifugal force. Through the numerical simulations, the model showed its capability that were in good agreement with experimental data with respect to free surface elevation, velocity, and turbulence characteristics.

• The Korean Journal of Food And Nutrition
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• v.28 no.3
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• pp.493-498
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• 2015

The aim of this study is to investigate the changes in the quality characteristics of cheonggukjang made with germinated soybeans, which is produced by the addition of a smoking process. The L value of smoked cheonggukjang made with germinated soybeans (SCGS) was higher than that of non-smoked cheonggukjang made with non-germinated soybeans (NCNS) and non-smoked cheonggukjang made with germinated soybeans (NCGS). The a value of NCNS was the highest, followed by NCGS and SCGS. The b and ${\Delta}T$ values had a similar tendency compared with the L value. The amino acids in NCGS were significantly decreased compared with NCNS, whereas no remarkable difference in amino acid content was observed between NCGS and SCGS. The moisture content of NCGS ($61.9{\pm}0.9%$) was increased by more than 8% compared with that of NCNS ($53.3{\pm}0.7%$). The moisture content of SCGS was significantly decreased compared with NCGS, whereas the moisture content of SCGS was higher than that of NCNS. The pH of SCGS was significantly the highest, followed by NCGS and NCNS. The viscous substance content of NCGS was significantly increased compared with that of NCNS. No remarkable difference in viscous substance content was observed between NCGS and SCGS. The number of aerobic bacteria in SCGS was significantly decreased compared with NCGS. The levels of total isoflavone in NCNS, NCGS, and SCGS were $1,573.9{\pm}62.5$, $1,759.1{\pm}65.8$, $1,738.0{\pm}68.1mg%$, respectively.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.1
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• pp.229-240
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• 1991

The large camber angle theory of turbomachine blade of compressor has been developed recently for the two-dimensional flow by Hawthorn, et al. However, in the above theory it was assumed that the fluid was incompressible and inviscid, and the blades had no thickness. In this study, the flow in a blade cascade being mounted in parallel fashion with blade of arbitrary thickness is studied in order to determine the effects of the camber angle on the performance characteristic of the blade section under the consideration of compressibility and viscosity of fluid. The panel method is used for potential flow analysis. The flow in the boundary-layer is obtained by solving the integral boundary-layer structure through the laminar, transitional , and turbulent flow using the pressure field determined from the potential flow. And then the viscous-inviscid interaction scheme is used for interaction of these two flows. For the determination of the variation in the outlet fluid angle influenced by deviation in cascade flow, the superposition method which is used for single foil is introduced in this analysis. By the introduction of this method, the effects of the deviation on outlet fluid angle and the resulting fluid angle are made to adjust for oneself through the calculation. As the result of this study, the blade of large camber angle, large incidence angle, large pitch-chord ratio has large viscous and compressible effect than those of small camber angle. Lift force increase as camber angle increases, but above 60.deg. of camber angle, lift force decrease as camber angle increases. But drag force increases linearly with camber angle increases in the entire region.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2003.10a
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• pp.204-212
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• 2003

As the first step to investigate the nonlinear interactions between turbulence and marine structures inside a viscous NWT, a LES technique was applied to the turbulent channel flow for $Re_{T}=150$, in this paper. The employed models were 4 types, such as the Smagorinsky model, the Dynamic SGS model, the Structure Function model and the Generalized Normal Stress model. The simulated data in time-series for the LESs were averaged in both time and space and performed statistical analysis. And results of the LESs were compared with those of a DNS developed in the present study and two spectral methods by Yoon et al.(2003) & Kim et al.(1987). It seems to be quite difficult to evaluate their performances to the present problem, but is seen that the accuracy of LESs are still related to the number of grids(or fine grid size).

• Journal of the Computational Structural Engineering Institute of Korea
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• v.23 no.5
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• pp.517-524
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• 2010

In this paper the progressive collapse resisting capacity of steel moment frames with viscous dampers was evaluated by nonlinear dynamic analysis. The effects of dampers installed in steel beam-column sub-assemblages with varying natural period and yield strength were evaluated after sudden removal of a column. According to the parametric study the vertical displacement general decreased as the damping ratio of the system increased, and the dampers were effective both in elastic and elasto-plastic systems. The nonlinear dynamic analysis results of the 15-story analysis models showed that the decrease in vertical deflection of the structure with 9m span length, which showed larger deflection, was more predominant than that of the structure with 6m span length.

• Journal of the Korean Society of Safety
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• v.31 no.5
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• pp.95-101
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• 2016

This study proposes a multi-scale dynamic system reliability analysis of control system as a method of quantitative evaluation of its performance in probabilistic terms. In this second paper, we discuss the control effect of the viscous damper on the seismic performance of the structure-level failure. Since the failure of one structural member does not necessarily cause the collapse of the structural system, we need to consider a set of failure scenarios of the structural system and compute the sum of the failure probabilities of the failure scenarios where the statistical dependence between the failure scenarios should be taken into account. Therefore, this computation requires additional system reliability analysis. As a result, the proposed approach takes a hierarchial framework where the failure probability of a structural member is computed using a lower-scale system reliability with the union set of time-sequential member failures and their statistical dependence, and the failure probability of the structural system is again computed using a higher-scale system reliability with the member failure probabilities obtained by the lower-scale system reliability and their statistical dependence. Numerical results demonstrate that the proposed approach can provide an accurate and stable reliability assessment of the control performance of the viscous damper system on the system failure. Also, the parametric study of damper capacity on the seismic performance has been performed to demonstrate the applicability of the proposed approach through the probabilistic assessment of the seismic performance improvement of the damper system.