• The Journal of Korean Association of Computer Education
• /
• v.12 no.3
• /
• pp.31-40
• /
• 2009

English education taken with native English speakers is very effective, but it is hard to obtain English education with native English speakers in rural schools. In this study, therefore, we supported English education with on-line content and video conferencing with native English speakers. This study worked with one hundred fifty students from six elementary and middle schools equally distributed by city size over three months. This study performed experimental research by T-test comparing of pre- and post-tests of the hybrid model. In our results, the upper group showed greater improvement in understanding while the lower group showed more improvement in writing. In addition, the lower group showed more improvement than the upper group in overall English accomplishment.

• Journal of the Korean Society for Precision Engineering
• /
• v.23 no.11 s.188
• /
• pp.93-102
• /
• 2006

In this study an advanced domain decomposition method is suggested in order to construct surface models from very large amount of points. In this method the spatial domain of interest that is occupied by the input set of points is divided in repetitive manner. First, the space is divided into smaller domains where the problem can be solved independently. Then each subdomain is again divided into much smaller domains where the problem can be solved locally. These local solutions of subdivided domains are blended together to obtain a solution of each subdomain using partition of unity function. Then the solutions of subdomains are merged together in order to construct whole surface model. The suggested methods are conceptually very simple and easy to implement. Since RDDM(Repetitive Domain Decomposition Method) is effective in the computation time and memory consumption, the present study is capable of providing a fast and accurate reconstructions of complex shapes from large amount of point data containing millions of points. The effectiveness and validity of the suggested methods are demonstrated by performing numerical experiments for the various types of point data.

• Textile Coloration and Finishing
• /
• v.17 no.1
• /
• pp.30-37
• /
• 2005

The tensile properties, acetic acid solubility and degree of swelling in distilled water of cellulose/chitosan and sericin/chitosan film blended by mixing chitosan acetic acid solution with cellulose solution or sericin solution were investigated and the effect of crosslinking agent on solubility and degree of swelling were also considered. From the experimental results, the model of intermolecular bond is proposed. Tensile modulus of 100% cellulose film is high but the tensile strength and elongation are low. The elongation of 100% chitosan film is high but tensile modulus and strength is low. But it is possible to make film having same or higher tensile strength and modulus compared to that of 100% cellulose film by mixing cellulose and chitosan or by mixing sericin and chitosan. Chitosan is solved in 5vol % acetic acid solution but cellulose and sericin are not solved. Degree of swelling of chitosan in distilled water is higher than that of cellulose and sericin. Lower than 40wt% chitosan content, the solubility of cellulose/chitosan film in 5vol % acetic acid solution shows lower expected value but higher in case of sericin/chitosan film.

• 한국연소학회:학술대회논문집
• /
• 1998.10a
• /
• pp.123-129
• /
• 1998

A numerical study has been conducted to investigate the effect of shock waves on the mixing and the recirculation zone of a hydrogen jet diffusion flame in a supersonic combustor. The general trends are compared with the experimental results obtained from the supersonic combustor at the University of Michigan. For the numerical simulation of supersonic diffusion flames, multi-species Navier-Stokes equations and detailed chemistry reaction equations of $H_2$-Air are considered. The $K-{\omega}/k-{\varepsilon}$ blended two equation turbulent model is used. Roe's FDS method and MUSCL method are used for convection fluxes in governing equations. Numerical results show that when slender wedges are mounted at the combustor wall the mixing and the combustion are enhanced and the size of recirculation zone is increased . The flame shape of supersonic flames is different in the flame-tip; it is not closed but open. The flame shape is shown to be greatly affected by shock waves.

• Journal of the Korean BIBLIA Society for library and Information Science
• /
• v.26 no.2
• /
• pp.173-197
• /
• 2015

The purpose of this study proposes continuing education program development for disability services librarian training. To this end, there was researched and analysed the Curriculum for the librarian disability service training courses and the library services with disability and LIS curriculums in abroad and domestic. Based on the research results obtained by the more comprehensive study developed a model for continuing education programs to strengthen disability services librarian competencies. Models were divided program is being offered to Track 1, 2. There are Education types which are organized cyber-shaped form of education training, set-type training, and was organized in blended learning.

• Tribology and Lubricants
• /
• v.38 no.3
• /
• pp.109-114
• /
• 2022

This paper reports the development of an oil flushing system combined with a microbubble generator. Oil flushing plays a crucial role in regulating the lubricant's performance during the lubricant replacement process. Moreover, harmful contaminants, such as sludge, wear particles, and rust, from piping systems or lubrication system can be removed by oil flushing. Oil flushing aims to increase the system's efficiency using a dedicated flushing oil, increasing of the supply pressure and generating a vortex. In addition, it helps the mechanical system or equipment achieve peak performance and reduces the potential for premature failure. However, the contaminant-removal applications of existing oil flushing system are limited. In this research, we aim to improve the performance of oil flushing system by incorporating a microbubble generator, which uses the venture effect to generate microbubbles and mixes them with lubricant. The microbubbles in the blended lubricant remove contaminants from the lubrication system more effectively. Structural mechanics and fluid dynamics are analyzed through fluid-structure interaction (FSI) analysis, and the numerical analysis results are used for the designing the system. The magnitude of the maximum stress is investigated based on the pressure results obtained by the CFD analysis; through the CFD analysis, the mixing ratio of air (bubble) and lubricant is evaluated using the volume of fluid (VOF) model according to the working conditions.

• Advances in aircraft and spacecraft science
• /
• v.10 no.2
• /
• pp.141-158
• /
• 2023

In current research work, the aerodynamics performance of a newly designed large flying V aircraft is numerically investigated. Three Flying V configurations, with V-angles of 50°, 70° and 90° that represent the minimum, moderate, and maximum configurations respectively, were designed and modeled to assess their aerodynamic performance at cruise flight conditions. The unstructured mesh was developed using ICEM CFD and Ansys-Fluent was used as an aerodynamic solver. The developed models were numerically simulated at cruise flight conditions with a Mach number equal to 0.15. K-ω SST turbulence model was chosen to account for flow turbulence.The authors performed steady flow simulations.The results obtained from the experimentation reveal that the maximum main angle configuration of 90° had the highest C_Lmax value of 0.46 compared to other configurations. While the drag coefficient remained the same for all three configurations, the 50° V-angle configuration achieved the maximum stall angle of 35°. With limited stall delay benefits, the flying V possesses no sufficient stability, due to the flow separation detected at whole elevon and winglet suction side areas at AoA equal and higher than 30°.

• The Bulletin of The Korean Astronomical Society
• /
• v.46 no.2
• /
• pp.37.1-37.1
• /
• 2021

Observations suggest the star formation in nuclear rings of barred galaxies proceeds episodically in time and sometimes asymmetrically in space. Existing theories and numerical simulations suggest that the episodic star formation is perhaps due to either supernova feedback combined with fluid instabilities or time-varying mass inflow rate. However, it has been challenging to discern what dominates in shaping the star formation history because the effects of the inflow and feedback are blended in global simulations of nuclear rings. To understand their effects separately, we construct semi-global models of nuclear rings, which treat the mass inflow rate as a model parameter. By running simulations with the inflow rates kept constant or oscillating in time, we find that the star formation rate (SFR) of the rings varies coherently with the inflow rate, while the feedback is responsible only for stochastic fluctuations of the SFR within a factor of two. The feedback instead plays an important role in maintaining the vertical dynamical equilibrium and setting the depletion time. While the asymmetry in the inflow does not necessarily lead to the asymmetry in the star formation, we find that the rings undergo a transient period of lopsided star formation when the inflow rate of only one dust lane is suddenly increased.

• Journal of Korean Biological Nursing Science
• /
• v.26 no.2
• /
• pp.71-82
• /
• 2024

Purpose: This study systematically analyzed the impact of aromatherapy on pain in individuals with diabetes. Methods: A search was performed in seven electronic databases based on the PICO-SD (Population, Intervention, Comparison, Outcome, Study Design) framework. The population (P) of interest was individuals with diabetes, and the intervention (I) included aromatherapy targeting pain reduction. The comparison (C) consisted of control groups that received no intervention, another intervention, or usual care. The outcome (O) measured was pain. The quality of the selected literature was assessed using the Joanna Briggs Institute checklist. In MIX 2.0 Pro, the pooled overall effect of pain was calculated using Hedge's g and a random-effects model, and heterogeneity was calculated using the Q statistic and Higgin's I2 values. Meta-regression and exclusion sensitivity analyses were performed. Results: Five articles and seven studies were included, showing a significant pooled overall effect of aromatherapy on diabetes-related pain (Hedge's g = -1.83, 95% CI: -2.76 to -0.91). Meta-regression demonstrated that effectiveness in reducing pain was associated with studies conducted in West Asia, those with IRB approval, and those receiving funding. Additionally, interventions involving subjects under 60, lavender oil (vs. turpentine oil or blended oils), massage therapy (vs. topical application), fewer hours per session, and more repeated measurements (vs. pre/post measurements) were associated with pain reduction. Conclusion: Aromatherapy, especially with lavender oil, effectively manages diabetes-related pain. Short-duration massage application is also effective. A personalized selection of oil type and application method could optimize therapeutic outcomes for individuals with diabetes.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.12
• /
• pp.504-510
• /
• 2016

This study presents a model for blended problem-based learning (BPBL) for engineering colleges in Mongolia in order to efficiently train talented Mongolian specialists "With problem-solving skills for the current information technology era. BPBL is learner-centered teaching method that promotes learning. Moreover, current teaching methods in the engineering colleges of Mongolia should change to novel and flexible teaching environments and methods that meet learners' needs. Thus, using BPBL for engineering education development in Mongolia will provide more teaching possibilities, which will assist the professors. Over the past few years, universities in Mongolia have established the Center for Teacher Development, which provides training and gives advice to staff about teaching methods, although the majority of lectures are still fragmentary and anecdotal. Therefore, many professors teach the way they learned, and most teaching methods used up till now have been teacher-centered. However, modern college instructors and modem society demand different engineering teaching methods from teachers who are more familiar with old-fashioned methods. Furthermore, the methods should meet the needs of individuals and groups who prefer to apply technology in the engineering learning process. Using an effective engineering strategy in the development of a new engineering teaching method will lead to its success.