• Journal of Advanced Marine Engineering and Technology
• /
• v.41 no.1
• /
• pp.36-43
• /
• 2017

The results of a numerical study on the performance of a propeller operating near a free surface are presented in this paper. The simulations are verified through comparison with experimental data, which was performed in a circulating water channel. The propeller performance as a function of the submerged depth was investigated. The effect of the propeller advance ratio on the wave patterns, flow structures around propeller, and thrust and torque of the propeller was also studied. Air ventilation was not observed for low advance coefficients. However, the simulations showed that wave pattern was strongly related to the tip vortex strength and inflow velocity. When air ventilation does not occur, the deduction of propeller thrust and torque increase for high advance coefficients.

• Journal of the Korean Society of Safety
• /
• v.32 no.6
• /
• pp.61-67
• /
• 2017

Suspended sediment transport plays principal roles in morphological process of natural coastals. It is needed to understand the reason why interaction characteristics of solitary wave and suspended sediment. The present study shows that suspended sediment pickup derived on solitary wave celerity. The 2D prismatic open channel length is 12 m, width is 0.8 m, height is 0.75 m and slope is 1/6. Generation of solitary wave is used by rapidly opening the sluice gate. Bottom surface sediments are laid movable slope section by 0.03 m thickness and experimental sediments are used anathracite and jumoonjin sand. Techniques of suspended sediment pickup rate are designed equipment ASC(Absorptive Suspended sediment Collector). It could directly absorb 5 points suspended sediment by channel water depth. Solitary wave celerity is measued by ADV(Acoustic Doppler Velocimeter). Mounted two video cameras(Model No. : Sony, HDR-XR550) are used to image processing of suspended sediment concentration and turbidity. Suspended sediment pikcup rate(Einstein, 1950) is analyzed to nondimensionalization based on solitary wave celerity. The suspended sediment pickup rate is suggested that more effective plunging breaking type than spilling. The results indicates fundamental suspended sediment transport mechanism between solitary wave celerity and suspended sediment pickup based on laboratory experiments. Finally, the present study suggests that suspended sediment pickup rate by solitary wave is used only characteristics of sediment and solitary wave celerity.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.29 no.1
• /
• pp.46-61
• /
• 2017

In the present work, the interaction analysis between tsunami bore and onshore bridge is approached by a numerical method, where the tsunami bore is generated by difference of upstream side and downstream side water levels. Numerical simulation in this paper was carried out by TWOPM-3D(three-dimensional one-field model for immiscible two-phase flows), which is based on Navier-Stokes solver. In order to verify the applicability of force acting on an onshore bridge, numerical results and experimental results were compared and analyzed. From this, we discussed the characteristics of horizontal force and vertical force(uplift force and downward force) changes including water level and velocity change due to the tsunami bore strength, water depth, onshore bridge form and number of girder. Furthermore, It was revealed that the entrained air in the fluid flow highly affected the vertical force.

• Journal of the Korean Ceramic Society
• /
• v.34 no.6
• /
• pp.652-658
• /
• 1997

The phase stability in the interface of Sr-doped LaMnO3(LSM)/Gd-doped CeO2(CGO) was examined in this study in order to check the feasibility of using LSM as the cathode material in a low-temperature SOFC(solid oxide fuel cell) using CGO as the electrolyte. For the purpose, CGO powders of Ce0.82Gd0.18O0.91 and two LSM powders having different compositions, La0.9Sr0.1MnO3(LSM10) and La0.5Sr0.5MnO3(LSM50), were synthesized using Pechini method. Then, specimens having the LSM/CGO interface were prepared, heat-treated at 130$0^{\circ}C$ for up to 3 days, and analyzed by XRD and STEM/EDX. Face-centered cubic CGO powders of less than 10 nm size were obtained by calcination of polymeric precursor formed in the process at 45$0^{\circ}C$. Higher calcination temperature of $700^{\circ}C$ was necessary for monoclinic LSM10 and cubic LSM50 powders. LSM powders were coarser than CGO and observed to be in the range of 50~100 nm. No trace of LSM-CGO interaction product was found in the XRD pattern. Also it was known from the concentration profile in the vicinity of the interface that interdiffusion was occurred over only a small penetration depth of ~100 nm order.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2003.05a
• /
• pp.157-164
• /
• 2003

Introduction of wave model, considered the effect of tide, wind and wave induced currents at the coastal waters of complex bathymetry, is a very important factor for most coastal engineering design and disaster protection problems. As the steady state spectral wave model could simulate depth induced wave shoaling and refraction, current induced refraction effect, steepness induced wave breaking, diffraction, wind wave growth, and wave-wave interaction that redistribute energy, this would support and compensate the gap in the real field of design where other wave models could not deal and cause wrong estimation. In this study, for that sense, we applied the spectral wave model t the large coastal waters near Gaduck Island where the Busan new port construction project is going on, for better understanding and analysis of wave transformation process. We also compared the simulation results with the calculated from the existing model. From such a trial of this study, we hope that broader and sager use of the spectral model in the area of port design and disaster prevention system come through in near future.

• Journal of the Korea Convergence Society
• /
• v.10 no.2
• /
• pp.277-284
• /
• 2019

This study is positive research to figure out enculturation types and to analysis influence of enculturation types on life's satisfaction of the marriage immigrant women. By precedent study, enculturation types was classified by integration factor, separation factor, assimilation factor and marginalization factor. To achieve objectives of study, we carried out sampling, survey and statistical analysis. According to result of study, integration factor and assimilation factor were appeared positive influence and separation factor was appeared negative influence statistically on quality of life of them. Therefore for quality of life of the marriage immigrant women, it need to develop interact system with native persons, support opportunity to associate with koreans, and promote fair treatment and interaction of koreans for them. And government have to execute multiculturalism policy more than assimilation policy. this study have that was samples's regional limitation, few variables limitation, and cross-sectional research's limitation. Therefor it needs more wide and depth research than this for future.

• Journal of Korean Theatre Studies Association
• /
• no.49
• /
• pp.171-208
• /
• 2013

Site-specific performance is always the real on-site work taking place at the site. Hence, it deals with the reality, in other words, the time of creation and formation. And it creates value and meaning through the interaction and continuous direct communication process between the performers, audience and the local residents. In this performance, the audience's status as the passive observer changes. They become the co-agent who actively lead and complete the performance through their own experience. We have examined the The Working Methods of Site-specific Performance and Aesthetics of Effect through four Korean performances ; Marie, An aesthetic experiment of site as the storyteller; Heterotopia and Urban Movement Research or Play: We Will Move Your Sofa, as performances which have Revealed history, politics, institution engraved in the site ; A Song of Mandala and Miracle, as a ritualistic site-specific performance at the historic site. Some remarks on Site-specific performance ; First, In Site-specific performance, the habitus peculiar to the stage art and the mode of reception are changed. Second, a new mode of theatrical communication requires creator and audience to have a sharp aesthetic sensibility and to change one's perceptual habit. Third, Site-specific performance can act as a demonstration for the viewpoints of political activism through what could be called a dramatic close-up effect. Fourth, Site-specific performance also has the risk of merely becoming an unfocused and scattered performance or degenerating into a pseudo-sightseeing. To avoid this, an in-depth study of the site and its socio-cultural context, and the clear motivation with which one is trying to reveal and tell from the site must be indispensable. As the co-agent, the audience should also be aware and think about what the given performance signifies today.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
• /
• v.8 no.8
• /
• pp.883-892
• /
• 2018

Recently, as interest in social robots to support physical convenience and emotional sympathy has increased, and social internet has developed, a social robot has evolved as various services simply beyond robot function. Therefore, to develop a social robot service effectively, it is required to study the functional application and methods of interaction between user and social robot service. The purpose of this study is to classify social robot services and to suggest the types of elements that need to be considered in service development. To do this, we conducted in-depth case studies and analysis based on the theoretical definitions and characteristics of social robots. Then, based on the sympathy and functions, we classified social robot services into 1) emotional support type, 2) companion type, 3) guide type, and 4) life support type. In addition, in this study, we derive the considerable factors according to the classified types for the development of effective social robot services. This study will contribute to the understanding and development of various services using a social robot.

• Health Policy and Management
• /
• v.21 no.3
• /
• pp.425-456
• /
• 2011

Background: Organizations in the pharmaceutical industry are highly dependent on the institutional environment. The introduction of pharmacoeconomics to the decision-making on the price and reimbursement decisions became strong constraints to pharmaceutical companies in Korea. As little is known about the issue on organization-environment interaction in the healthcare field, this study aimed to figure out how pharmaceutical companies adapted to the environmental changes. Methods: A multicase study method was used, selecting eight cases among multi-national pharmaceutical companies in South Korea. In-depth interviews were conducted with the managers of these organizations, and secondary data were reviewed to complement the interviews. Results: Pharmaceutical companies viewed the new policies as a big threat and sought for actions against them. One of the most distinguishing organizational changes was to construct a Market Access department. Other strategies managing the environment such as co-optation, forecasting, and bargaining were also implemented. These changes were consistent with the predictions of Resource Dependency Theory and Institutional Theory. Conclusions: The interactions between pharmaceutical companies and institutional environments in healthcare were first explored. This study presents a new perspective on how organizations change and the motives for the changes. The findings of this case study will form the basis of further empirical studies.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.18 no.4
• /
• pp.352-359
• /
• 2012

An experiment was carried out to figure out the turbulence flow characteristics in the wake of the transom stern's 2-dimensional section by 2-frame grey level cross correlation PIV method at Re= $3.5{\times}10^3$, Re= $7.0{\times}10^3$. The angles of transom stern are $45^{\circ}$(Model "A"), $90^{\circ}$(Model "B") and $135^{\circ}$(Model "C") respectively. The depth of wetted surface is 40mm from free surface. Strong turbulence intensity appears at the interaction between the flow separation of the bottom of a model and the free surface. This study provides statistic flow information such as turbulence intensity, Reynolds stress and turbulence kinetic energy. Model C type (Raked transom) has low Reynolds stress and turbulence kinetic energy.