• Journal of Korea Water Resources Association
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• v.33 no.2
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• pp.181-193
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• 2000

This paper presents the flow and the suspended sediment movement over ripples for oscillatory flows. A new numerical model system is developed, and applied to a laboratory experimental condition of regular waves and a fictitious condition of irregular waves. The flow field is obtained from a programme proposed by Kim et. al.(1994), which is a modified version of SOLA based on SMAC scheme. The sub-model solves the continuity and Reynolds momentum equations in the x-z plane. The wave orbital velocities, shear stresses, and pressure are all reasonably reproduced by the model. The model results on the vertical velocity component show good agreement with the measurements. The suspended sediment transport sub-model is newly set up to solve the advection-diffusion equation of suspended sediment using a split method, and involving a special shear entrainment from the whole ripple surface. The calculated suspended sediment concentrations for regular waves show reasonable agreement with measurements at Deltaflume. The model results for random waves show that the suspended sediment concentration is higher than those for regular waves and that the sediment diffuses higher than for regular waves with the significant wave height and the peak wave period of the irregular waves.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.36 no.2
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• pp.70-79
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• 2024

In this study, we introduce a linear spectral method capable of simulating wave generation and transformation caused by a moving bottom in a 3-dimensional space. The governing equations are linear dynamic free-surface boundary conditions and linear kinematic free-surface boundary conditions, which are solved in Fourier space. Solved velocity potential and free-surface displacement should satisfy continuity equation and kinematic bottom boundary condition. For numerical analysis, a 4th order Runge-Kutta method was utilized to analyze the time integral. The results obtained in Fourier space can be converted into velocity potential and free-surface displacement in a real space using inverse Fourier transform. Regular waves generated by various types of moving bottoms were simulated with the linear spectral method. Additionally, obliquely generated regular waves using specified bottom movements were simulated. The results obtained from the spectral method were compared to analytical solutions, showing good agreement between the two.

• Journal of the Korean Society of School Health
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• v.18 no.2
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• pp.15-26
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• 2005

Purposes： This review is designed to assess the current status of health education in Korea, to identify problems within the curriculum, and to suggest ways to improve health education in Korea. Results： Korean schools currently lack a regular standardized health education curriculum. Subjects related to health education are presently taught in other disciplines, such as physical education, home management, biology, and other related subjects. The Korean health education curriculum suffers from many significant problems, including a lack of educational goals for health education, absence of designated time for health education, a lack of continuity between contents, knowledge-oriented health education, and an overall disconnect with the needs of the students. Other problems include an exclusion of health education experts in the development of the curriculum, no designated times for health education within the regular curriculum, and a lack of health teachers in schools. Conclusion： To improve health education in schools, standard health education curriculum should be developed. Health education curriculum needs to be sequential, comprehensive, and skill-based. Health education needsto be a essential subject, health teachers need to be trained, and provided with technical support.

• Journal of Korean Academy of Nursing
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• v.34 no.8
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• pp.1460-1467
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• 2004

Purpose. This study examined the predictive factors enabling access to children's oral health care at the level of financial barriers, beliefs, and the provider. Methods. In-depth interviews were conducted with 320 immigrant mothers of low-income families regarding their use of oral health services for children aged four to eight years old. Access to oral health care was measured with frequency of planned dental visits, continuity of care, and age at first visit to dentist. Results. The mother took her child to the dentist at a younger age if she received referrals to a dentist from pediatrician. Regular dental visits were significantly related to household income, provider availability on week-ends, and insurance coverage. The extended clinic hours in the evenings, and the belief in the importance of the child's regular dentist visits increased the likelihood of continuing care. The mothers perceiving a cost burden for the child's dental care were also less likely to return to the dentist. Conclusion. The available care delivery system, coordinated medical care, and health beliefs were among important predictors of the health service use. The study findings suggest need for culturally competent dental health interventions to enhance access to oral health care among particularly vulnerable populations such as low-income children in Korean communities.

• Atmosphere
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• v.18 no.4
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• pp.417-427
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• 2008

In this paper, we analyzed the physical and thermodynamic characteristics of fog by using the integrated water vapor (IWV) from Global Positioning System (GPS) networks and the regular observation data of meteorological stations in GPS sites. The cases of a radiation and an advection fog were selected as samples, the conversions of water substance from the water vapor to cloud water in fog were detected by the Bulk Water-Continuity Model, and the pattern analysis is adapted on GPS IWV, temperature, wind and relative humidity. Under the specific hypothesis (saturation and stable), GPS IWV could detect quantitatively the phase changing between the water vapor and cloud water content with condensation/evaporation during the formation and dissipation of fog. After it reaches to the saturation, the relative humidity can be a limited indicator for fog. However, GPS IWV can detect the status change of fog even after the saturation. It has indicated that GPS IWV could be a new observing technique for the processes of the fog formation and the dissipation.

• Journal of the Society of Naval Architects of Korea
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• v.47 no.2
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• pp.188-195
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• 2010

Green water load is an important parameter to be considered in designing a modern ship or offshore structures like FPSO and FSRU. In this research, a numerical simulation method for green water phenomenon is introduced. The Navier-Stokes equations and the continuity equation are used as governing equations. The equations are calculated using Finite Difference Method(FDM) in rectangular staggered grid system. To increase the numerical accuracy near the body, the Cartesian cut cell method is employed. The nonlinear free-surface during green water incident is defined by Marker-density method. The green waters on a box in regular waves are simulated. The simulation results are compared with other experimental and computational results for verification. To check the applicability to moving ship, the green water of the ship which is towed by uniform force in regular wave, is simulated. The ship is set free to heave and to surge.

• Research in Community and Public Health Nursing
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• v.16 no.4
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• pp.467-477
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• 2005

Purpose: This study was to identify adolescents' smoking behavior and the status and need of smoking prevention education for adolescents. Method: The subjects were 375 students selected through convenient sampling from three middle schools and three high schools in Jeonbuk. Data were collected through a questionnaire survey and analyzed using SPSS 10.1. Result: The smoking rate was 20.8% and 83.7% the students experienced smoking prevention education. Students were educated by a special instructor (39.8%) or a health teacher (26.8%). Among the teaching methods, lecture was 69.4%, but some students (30.7%) wanted anti-smoking school. Among the students, 85.0% answered they want smoking prevention education and 46.7% said that it should be covered in regular curriculum. Conclusion: High interest and continuity are emphasized for the success of smoking prevention education. In addition, various teaching methods need to be developed including anti-smoking school, lectures, counselling and long term education program. Moreover, smoking prevention education programs need to be covered in regular curriculum.

• Journal of Ocean Engineering and Technology
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• v.17 no.4
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• pp.1-7
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• 2003

A virtual reality technology for multipurpose numerical simulation is developed to reproduce and investigate a variety of ocean environmental problems in a 3D Numerical Wave Tank(NWT). The governing equations for solving incompressible fluid motion are Navier-Stokes equation and continuity equation. The Marker-Density function technique is adopted to implement the fully nonlinear freesurface kinematic condition. The marine environmental situations, i.e., waves, currents, etc., are reproduced by use of multi-segmented wavemakers on the basis of the so-called ″snake-principle″. In this paper, some numerical reproduction techniques for regular, and irregular waves, multi-directional waves, Bull's-eye wave. wave-current, and solitary wave are presented, and a model test in motion with large amplitude of roll angle is conducted in the developed 3D-NWT, using a overlaid grid system.

• Journal of Communications and Networks
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• v.7 no.4
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• pp.499-508
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• 2005

In this paper, we address the problem of efficient routing and wavelength assignment (RWA) in multi-fiber wavelength division multiplexing (WDM) networks without wavelength translation, under dynamic traffic. We couple Dijkstra's shortest path algorithm with a suitable weight function which chooses optical paths based both on wavelength availability and multi-fiber segments. We compare our approach with other RWA schemes both for regular and irregular WDM multi-fiber network topologies in terms of blocking probability and overall link utilization.

• East Asian mathematical journal
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• v.31 no.1
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• pp.65-75
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• 2015

In modern times, coupled fixed point theorems have been rigorously studied by many researchers in the milieu of partially ordered G-metric spaces using different contractive conditions. In this note, some coupled fixed point theorems using mixed monotone property in partially ordered G-metric spaces are obtained. Furthermore some theorems by omitting the completeness on the space and continuity conditions on function, are obtained. Our results partially generalize some existing results in the present literature. To exemplify our results and to distinguish them from the existing ones, we equip the article with suitable examples.