• Korean Journal of Health Education and Promotion
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• v.14 no.2
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• pp.43-57
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• 1997

Educational goals of SPH were two-fold : One was to train a health professions who should take charge of a leading roles, another were to educate the researchers of public health. There were strong demands to evaluate whether these goals had been effectively achieved through the master's course of SPH or not. According to the educational goals of SPH, public health is an applied science to be applicable to health-related fields. The curriculum of SPH has to be built under this principle and be evaluated by someone regularly. Who evaluates that? The most pertinent appraiser is the graduates of public health currently working at health-related jobs. It was the purpose of the study to let the graduates evaluate their education and the curriculum that they had undertaken during master's course at SNU. If the results of the evaluation by the graduates were not satisfactory, we should find the actual causes of low scored apraisal and reform the curriculum of SPH as the process of problem solving. During September and October 1996, a postal survey was undertaken of the 293 SNU graduates of public health who had been engaged in the health related jobs. As 198 graduates answered out of 293, the response rate was 67.6%. The questionnaire was designed to ascertain how well the SNU master's course of public health had helped their practice. The SAS package was used for statistical analysis and $x^2$-test as a test of statistical significance. Major findings of the study were summarized as follows: $\cdot$ The health related abilities consisted of three categories, which were health administration abilities composed of 14 items, health education abilities composed of 5 items, health research abilities composed of 10 items. $\cdot$ The respondents had acquired 'Worldwide trends of health policy', 'evaluation concepts of health projects', 'interpersonal relationships in professional life', and 'communication through writings' moe than other detailed items in the category of health administration abilities. $\cdot$ 'Establishment of educational and learning golas' was the most acquired item of 5 detailed items of health education abilities. $\cdot$ Respondents indicated that they had acquired ability 'to search reference', ' to understand health problems', 'to establish study plannings', and 'to collect health related data' more than other detailed items in the category of health research abilities.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.19 no.1
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• pp.81-96
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• 2007

Nonlinear shoaling characteristics over surf zone are numerically investigated based on spatially averaged NavierStokes equation. We also test the validity of gradient model for turbulent stresses due to wave breaking using the data acquainted during SUPERTANK LABORATORY DATA COLLECTION PROJECT(Krauss et al., 1992). It turns out that the characteristics length scale of breaking induced current is not negligible, which firmly stands against ever popular gradient model, ${\kappa}-{\varepsilon}$ model, but favors Large Eddy Simulation with finer grid. Based on these observations, we model the residual stress of spatially averaged NavierStokes equation after Lagrangian Dynamic Smagorinsky(Meneveau et al., 1996). We numerically integrate newly proposed wave equations using SPH with Gaussian kernel function. Severely deformed water surface profile, free falling water particle, queuing splash after landing of water particle on the free surface and wave finger due to structured vortex on rear side of wave crest(Narayanaswamy and Dalrymple, 2002) are successfully duplicated in the numerical simulation of wave propagation over uniform slope beach, which so far have been regarded very difficult features to mimic in the computational fluid mechanics.

• Journal of Aerospace System Engineering
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• v.13 no.2
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• pp.34-42
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• 2019

The existence of different thermodynamic properties results in various undesirable effects, such as thermal deformation and residual stress, in heat-welding processes. The solid-state junction, by using explosive or electromagnetic forces, i.e., high-velocity impact welding without employing heat is advantageous in joining materials with different thermodynamic properties. In the solid-state junction, the joining is performed within a short time, a high velocity and large deformations are accompanied by interfacial surfaces. The numerical analysis models play an important role in the understanding of the mechanism of high-velocity impact welding. However, in the analysis of high velocity and large deformations, the conventional Lagrangian method has low reliability due to the occurrence of entanglements. In this study, high-velocity impact welding between Cu and CP-Ti with different thermodynamic properties was performed using a un-gridded numerical method, SPH (Smoothed Particle Hydrodynamics), and interfacial morphology occurred. As a result of the analysis, the interfacial morphology was confirmed and the compared degree of shape (straight, vortex), period, length, and so on appeared differently depending on the relationship between the parameters (impact angle and speed).

• Journal of the Computational Structural Engineering Institute of Korea
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• v.34 no.1
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• pp.59-69
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• 2021

Recently, large-scale offshore and coastal structures have been constructed owing to the increasing interest in eco-friendly energy development. To achieve this, precise simulations of waves are necessary to ensure the safe operations of marine structures. Several experiments are required in the field to understand the offshore wave; however, in terms of scale, it is difficult to control variables, and the cost is significant. In this study, numerical waves under various wave conditions are produced using a piston-type wavemaker, and the produced wave profiles are verified by comparing with the results from a numerical wave tank (NWT) modeled using the smoothed particle hydrodynamics (SPH) method and theoretical equations. To minimize the effect by the reflected wave, a mass-weighted damping zone is set at the right end of the NWT, and therefore, stable and uniform waves are simulated. The waves are generated using the linear and Stokes wave theories, and it is observed that the numerical wave profiles calculated by the Stokes wave theory yield high accuracy. When the relative depth is smaller than two, the results show good agreement irrespective of the wave steepness. However, when the relative depth and wave steepness are larger than 2 and 0.04, respectively, the errors are negligible if the measurement position is close to the excitation plate. However, the error is 10% or larger if the measurement position is away from the excitation location. Applicable target wave ranges are confirmed through various case studies.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.5B
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• pp.559-573
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• 2008

In this study, we newly proposed 3-D nonlinear wave driver utilizing the Navier-Stokes Eq. the numerical integration of which is carried out using SPH (Smoothed Particle Hydrodynamics), an internal wave generation with the source function of Gaussian distribution and an energy absorbing layer. For the verification of new 3-D nonlinear wave driver, we numerically simulate the sloshing problem within a parabolic water basin triggered by a Gaussian hump and uniformly inclined water surface by Thacker (1981). It turns out that the qualitative behavior of sloshing caused by relaxing the external force which makes a free surface convex or uniformly inclined is successfully simulated even though phase error is visible and an inundation height shrinks as numerical simulation more proceeds. For the more severe test, we also simulate the nonlinear shoaling and refraction over uniform beach of wedge shape. It is shown that numerically simulated waves are less refracted than the linear counterpart by Hamiltonian ray theory due to nonlinearity, energy dissipation at the bottom and side walls, energy loss induced by breaking, and the hydraulic jump occurring when breaking waves encounter a down-rush by the preceding wave.

• Computational Structural Engineering
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• v.21 no.3
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• pp.59-67
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• 2008

• 한국전산유체공학회:학술대회논문집
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• 2008.08a
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• pp.29.5-30
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• 2008

• IT SoC Magazine
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• s.21
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• pp.52-52
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• 2007

• The Bulletin of The Korean Astronomical Society
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• v.17
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• pp.17.2-18
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• 1992

• Bulletin of the Korean Chemical Society
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• v.18 no.7
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• pp.685-686
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• 1997