• Journal of the Regional Association of Architectural Institute of Korea
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• v.21 no.3
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• pp.87-92
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• 2019

To relieve noise between floors in Korea, recent domestic and overseas studies have been developing materials that have the properties of ceramic, which is an inorganic compound, and polymer, which is an organic compound, to introduce a new function to polymer. This study conducted a bending strength experiment between re-bar and new composite concrete mixing POSS (Polyhedral Oligomeric Silses-quioxanes) nano complex on the inside of concrete, and by assembling the inside of each concrete with 3 and 4 main re-bars as an experiment to supplement various problems that occur by the expression of this strength and the distribution of the reinforcement. The number of the main re-bars. and the direction of laying the concrete were applied as the principal variables of the experiment. Upon experiment, there were no differences in the bond strength based on the location of the main re-bar, and a 2 % increase in the bond strength was shown in the specimen laid in the same direction as the main re-bar in comparison to that of the specimen laid in a different direction from the main re-bar. The experiment results displayed that the composite concrete had uniform performance based on the rapid reaction speed of POSS nano complex.

• Wind and Structures
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• v.22 no.4
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• pp.409-428
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• 2016

The mechanical and aerodynamic effect of building shape plays a dominate role in the pedestrian level wind environment. These effects have been presented in numerous studies and are available in many wind codes. However, most studies have focused on wind flow around conventional buildings and are limited to few wind directions. The present study investigated wind circulation in the re-entrant corners of cross-shaped high-rise buildings from various wind directions. The investigation focused on the pedestrian level wind environment in the re-entrant corners with different aspect ratios of building arrangements. Ninety cases of case study arrangements were evaluated using wind tunnel experimentation. The results show that for adequate wind circulation in the re-entrant corners, building orientations and separations play a critical role. Furthermore, in normal wind incident directions and at a high aspect ratio, poor wind flow was observed in the re-entrant corners. Moreover, it was noted that an optimized building orientation and aspect ratio significantly improved the wind flow in re-entrant corners and through passages. In addition, it was observed that oblique wind incident direction increased wind circulation in the re-entrant corners and through passages.

• Proceedings of the Korea Information Processing Society Conference
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• 2004.05a
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• pp.1389-1392
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• 2004

정보통신 및 인터넷의 급속한 발전으로 전자원문 서비스 등 웹 서비스가 활발하게 이루어지고 있으나, 기존 웹 서비스에 대한 연구는 웹 서비스를 차별화하기 위해 HTTP의 속도지연 문제해결이나 서비스 차별화 방안에 대해 이루어지고 있다. 그러나, 타 시스템의 웹 서비스와 연계시 해당 웹 문서에 대한 제어권 확보에 관한 연구는 미미하다. 따라서, 본 논문에서는 타 시스템의 웹 문서에 대해 제어권 확보를 위해 Re-Direction Agent를 활용하여 해외전자원문 연계시스템을 구현하고자 한다.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.20 no.5
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• pp.1649-1660
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• 1996

The flow around a circular cylinder was controlled by an acoustic excitation issued from a thin slit along the cylinder axis. The static pressure distributions around the cylinder wall and flow characteristics in the near wake have been measured. Experiments were performed under three cases of Reynolds number, 7.8 * 10$\^$4/, 2.3 * 10$\^$5/ and 3.8 * 10$\^$5/. The effects of excitation frequency, sound pressure level and the location of the slit were examined. Data indicate that the excitation frequency and the slit location are the key parameters for controlling the separated flow. At Re$\_$d/, = 7.8 * 10$\^$4/, the drag is reduced and the lift is generated to upward direction, however, at Re$\_$d/, =2.3 * 10$\^$5/ and 3.8 * 10$\_$5/, the drag is increased and lift is generated to downward direction inversely. It is thought that the lift switching phenomenon is due to the different separation point of upper surface and lower surface on circular cylinder with respect to the flow regime which depends on the Reynolds number. Vortex shedding frequencies are different at upper side and lower side. Time-averaged velocity field shows that mean velocity vector and the points of maximum intensities are inclined to downward direction at Re$\_$d/ = 7.8 * 10$\^$4/, but are inclined to upward direction at Re$\_$d/ = 2.3 * 10$\^$5/.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.1418-1423
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• 2004

A parametric study on the interactions of two spheres aligned in the streamwise direction is carried out using an immersed boundary method. The numerical results for the case of single sphere for the range of Re ${\leq}$ 300 are in good agreement with other authors' experimental and numerical results currently available. Then, our main investigation is focused on identifying the change of the vortical structures in the presence of a nearby sphere aligned in the streamwise direction for the range Re ${\leq}$ 220. It turns out that significant changes in physical characteristics are noticed depending on how close the two spheres are. In this paper, not only quantitative changes in the key physical parameters such as the force coefficients, but also qualitative changes in vortex structures are reported and analyzed.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.7
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• pp.789-799
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• 2004

An experimental study is conducted to investigate the effects of duct corrugation angle on heat/mass transfer characteristics in wavy ducts of a primary surface heat exchanger application. Local heat/mass transfer coefficients on the wavy duct sidewalls are determined by using a naphthalene sublimation technique. The corrugation angles(${\alpha}$) of the wavy ducts are 145$^{\circ}$, 130$^{\circ}$, 115$^{\circ}$ and 100$^{\circ}$. And the Reynolds numbers based on the duct hydraulic diameter vary from 300 to 3,000. The results show that at the low Re(Re $\leq$1000), the secondary vortices called Taylor-Gortler vortices perpendicular to the main flow direction are generated due to effect of duct curvature. By these secondary vortices, high heat/mass transfer regions are formed on both pressure-side and suction-side walls. At the high Re(Re $\geq$ 1000), these secondary flows are vanished with helping flow transition to turbulent flow and the regions which show high heat/mass coefficients by flow reattachment are formed on suction side. As corrugation angle decreases, the local peak Sh induced by Taylor-Gortler vortices increase at Re $\leq$1000. At high Re(Re $\geq$ 1000), by the existence of different kind of secondary flows called Dean vortices, non-uniform Sh distribution appears along spanwise direction at the narrow corrugation angle (${\alpha}$=100$^{\circ}$). Average Sh also increase by the enhanced effect of secondary vortices and flow reattachment. More pumping power (pressure loss) is required with the smaller corrugation angle due to the enhancement of flow instability.

• Journal of Korean Ophthalmic Optics Society
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• v.19 no.2
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• pp.189-198
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• 2014

Purpose: The present has analyzed the correlation between the direction of lens and the amount of rotation upon soft toric contact lens fitting after classifying the corneal astigmatism. Methods: Soft toric contact lens was fitted on 114 with-the-rule astigmatic eyes with total astigmatism of at least -0.75 D in their 20s and 30s according to the fitting guideline of the manufacturer and the correlation between the astigmatic degree and the rotational direction/amount of rotation was analyzed by when keeping the eyes on the front and by changing the direction of gaze. As for re-orientation movement. The speed of lens re-orientation and total amount of lens rotation was compared and analyzed by corneal astigmatism after mis-location of lens of $45^{\circ}$ to temporal and nasal direction, respectively. Results: The positive correlations were shown between corneal astigmatism and the direction of lens rotation and between corneal astigmatism and the amount of lens rotation. Meanwhile, the amount of lens rotation was different by the direction of gaze however, there was no correlation with corneal astigmatism. The speed of lens re-orientation was fastest in the group of high astigmatic degree when the lens was mis-located to both temporal and nasal directions. Conclusions: For optimal axis stabilization of toric soft lens, it is proposed that the adjustment of fitting guideline considering corneal astigmatism is necessary since the current fitting guideline is only based on total astigmatism.

• The Research Journal of the Costume Culture
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• v.21 no.4
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• pp.478-493
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• 2013

The purpose of this study is to examine the online WOM effect of blog review depending on brand awareness and message direction. The theory of planned behavior was applied to understand online WOM acceptance. A survey was conducted targeting female in 20s and 30s and 312 questionnaires were used for analysis. Frequency analysis, reliability analysis, t-test, and regression analysis were conducted using SPSS ver. 18.0. The results are as follows. First, purchase intention and online re-WOM intention are higher when brand awareness is higher. Second, subjective norm, perceived behavioral control, WOM acceptance intention, purchase intention and off-line re-WOM intention show higher values when negative information is afforded. Third, in type 1 (high brand awareness/positive message) and type 3 (low brand awareness/positive message), attitude, subjective norm and perceived behavioral control have a positive effect on WOM acceptance intention. In type 2 (high brand awareness/negative message), subjective norm and attitude have a positive effect on WOM acceptance intention. In type 4 (low brand awareness/negative message), subjective norm and perceived behavioral control have a positive effect on WOM acceptance intention. Forth, in type 1 and type 3, WOM acceptance intention has a positive effect on purchase intention, offline re-WOM intention and online re-WOM intention. In type 2 and type 4, WOM acceptance intention has a negative effect on purchase intention, and a positive effect on offline re-WOM intention. The results show that blog review has ripple effect on consumer behavior by affecting purchase intention and offline re-WOM intention.

• Journal of The Korea Institute of Healthcare Architecture
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• v.26 no.4
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• pp.49-57
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• 2020

Purpose: In our country, the aged population accounted for about 13% of the total population in 2018. In addition, it is expected to exceed 20% in 2026, entering an super-aged society. However, the senior welfare housing in Korea currently accommodates only 0.08% of the elderly population, and the increasing amount of the elderly population is very small. Accordingly, this study aims to analyze the causes of supply shortages and to propose directions for revitalizing the supply of welfare housing for the elderly in the private sector. Methods: First, the causes and problems of the poor supply of welfare housing for the elderly were analyzed. Next, the direction was proposed through institutional and case-by-case surveys and expert interviews. Results: It suggested directions such as legal and institutional improvement, inducing the use of REITs, preparing policies to support consumers, allocating a certain percentage of senior welfare housing for the elderly in the reconstruction project, improving awareness of monthly living expenses, and re-discussing sales permits. Implications: Experts said that the direction proposed in this study can have a positive effect on supply activation. However, there were many opinions that re-discussion on permission for sales was necessary due to the excessive impact of the inability to sell. In addition, further research is needed for specific application of the proposed direction.

• Journal of Aerospace System Engineering
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• v.14 no.2
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• pp.28-35
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• 2020

In this paper, we present a design for a retraction-type actuator (ReACT) that has the characteristics of both thermomechanical metamaterials and displacement amplification mechanisms. The ReACT consists of an actuating bar, a diamond-shaped displacement amplification (DA) structure, and a slot for loading thin-film heaters formed through the actuating bar. When power is supplied to the thin film heater, the actuating bars contacting the heater thermally expand, and the diamond-shaped DA structures retract in the longitudinal direction. The performance characteristics of the ReACT, such as temperature distribution and retracting displacement, were calculated with thermomechanical analysis methods using the finite element method (FEM). Subsequently, the ReACTs were fabricated using a polymer-based 3D printer that can easily execute complex structures, and the performance of the ReACT was evaluated through repeated tests under various temperature conditions. The results of the performance evaluation were compared with the results of the FEM analysis.