• The KSFM Journal of Fluid Machinery
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• v.15 no.6
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• pp.25-30
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• 2012

Renewable energy has been interested because of fluctuation of oil price, depletion of fossil fuel resources and environmental impact. Amongst renewable energy resources, hydropower is most reliable and cost effective way. In this study, to develop a new type of micro hydro turbine which can be operated in the range of very low specific speed, a cross-flow hydro turbine with simple structure is proposed. The turbine is designed to be used at the very low specific speed range of hydropower resources, such as very high-head and considerably small-flow rate water resources. CFD analysis on the performance and internal flow characteristics of the turbine is conducted to obtain a practical data for the new design method of the turbine. Results show that optimized arrangement of guide vane angle and inner guide angle can give contribution to the turbine performance improvement.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.1
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• pp.107-112
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• 2018

One-dimensional numerical model is implemented to investigate temperature variations in the mixed layer depth (MLD) with the passage of typhoons. In the model, we assume a non-divergent, infinite ocean and consider wind effects only, excluding isostatic effects (inverse barometric effects) and upwelling with vertical movement of the water column. Numerical experiments investigate the effects of typhoon tracks on temperature variations, including their dependence on vertical resolutions in the MLD and these results are compared with those in a three-dimensional primitive equation model (POM). The model reproduces features of the observed temperature variations in the MLD fairly well, and implies that wind effects, rather than isostatic effects, play a predominant role in temporal and spatial temperature variations in the MLD. After the passage of typhoons, however, the model does not reproduce well the temperature variations observed in the MLD, because a limitation of the model is its inability to reproduce events such as cyclonic eddy formation (Hong et al., 2011; Masuda and Hong, 2011). The model also shows well the so called 'rightward bias' (Price, 1981) of sea surface cooling which is the most predominant in the right hand side of typhoon's track.

• Journal of the Korean Society of Clothing and Textiles
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• v.20 no.5
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• pp.893-904
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• 1996

The main purpose of this research was to examine the purchase and use behavior of consumers related to washing machines in order to develope strategies to increase competitiveness of washing machines manufactured in Korea. Purchase and use behavior related to washing machines were examined by survey method and detailed information on washing conditions and usage of washing machines were obtained by diary method. 398 questionnaires were analyzed in the survey and 35 housewives participated in keeping the records of their washings for 30 days. The results of the survey showed that price and a tangle of clothes were the most determinant factors for purchase of washing machines and the knowledge related to washing was relatively low The diary method revealed that washing loads and frequencies of washing increase with the household size, and functions of washing machines except water level are infrequently used. Comparisons between the survey and diary results indicated that consistency between the two methods depends on the types of questions.

• Journal of Marine Bioscience and Biotechnology
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• v.2 no.2
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• pp.94-101
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• 2007

The status of recently expanded exotic pangasiid catfish Pangasius hypophthalmus, Pangasiidae farming in rural Bangladesh has been studied for finding research needs, through knowing the culture methods, associated activities and problems, to make the farming sustainable. Data were collected using participatory rural appraisal (PRA) tools in nine villages in three upazilas (sub-district) of Mymensingh district. The farmers have not got any formal training and have developed their knowledge on farming the fish through practice over years and sharing of knowledge among fellow farmers. Linked industries, e.g. hatcheries, nurseries, feed mills, trading of feed and fish etc. have developed that created employment opportunities. Most of the farmers produce two crops a year. About 90% of the farmers were found to practice mono culture of pangasiid catfish at high stocking density. The feeding rates started from 10-15% of the body weight per day at fingerling stage that reduced to 4-6% with growth. The average yield was found to be 25 tonslha/year. The livelihood of the farmers has been improved through farming the fish. Women and children were rarely engaged in the activities. The identified major problems in farming the fish were water quality deterioration, high feed costs and declining consumer demand and market price.

• Culinary science and hospitality research
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• v.13 no.2
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• pp.59-68
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• 2007

This research was to investigate the consumers' perception and purchase behavior of Korean rice cake as a meal. The rate of consumers who had eaten rice cake as a meal was 64.7% and that of those who had not was 35.3%.. For breakfast, 49.83% of them ate rice cake and for lunch 21.2% of them did. Reasons for eating rice cake for meal were investigated on 'easy to eat(63.21%), 'the others(13.0%)', 'good taste (12.3%)' and 'healthy food(10.8%)'. Reasons for not eating rice cake for meal were researched on 'snack(40.09%), 'difficult storage(21.9%)' and 'expensive(9.7%)'. After purchasing or making rice cake, 45.4% of consumers ate immediately and 30.9% of them ate within $1{\sim}2\;days$. In thawing methods of frozen rice cake as a meal, 51.3% of consumers used a microwave. Kinds of beverage with which rice cake was eaten were water(35.3%), coffee(14.9%), milk(13.8%) and Kimchi(dongchimi, 13.8%). The complementary points for purchase of rice cake as a meal were 'Small package(23.2%)', 'Good preference'(20.5%), 'Healthy food(15.0%)', 'Affordable price(12.7%)' and 'Low calorie(9.5%). Kinds of rice cake as a meal were Injeolmi(16.0%), Backsulgi(15.4%), Yaksik(9.3%) and Galaetteok(9.0%).

• Culinary science and hospitality research
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• v.15 no.1
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• pp.287-295
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• 2009

The purpose of the study was to investigate university students' using coffee shops. For this study, 265 university students in seoul were surveyed from October 6 to October 10, 2008, and 250 copies of the questionnaire were analyzed. A statistical data analysis was completed using SPSS programs. The results of this study revealed that the importance and performance which university students showed in using coffee shops were 4.03 and 3.01 out of 5 respectively. The Importance-Performance Analysis(IPA) used for obtaining information on coffee shops suggested that the items regarded as important but discontented were price, sanitation of ice, water, appliances, the store and employees in general, and cold storage condition.

• Proceedings of the KIEE Conference
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• 2005.04a
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• pp.277-279
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• 2005

The imbalance of energy demand and supply caused by rapid industrialization around the world and the associated environmental issues require and alternative energy source with possible renewable fuels. Political instability and depletion of cruel oils are other factors that cause fluctuation of oil price. Securing a new alternative energy source for the next century became an urgent issue that our nation is confronting with. As a matter of fact, the fuel cell technology can be widely used as next generation energy regardless of regions and climate. Specially, the ability of expansion and quick installation enable one to apply it for distributed power, where the technology is already gaining remarkable attentions for the application. Particularly, leading industrialized nations are focusing on the PEM fuel dell with anticipation that this technology will find their place of applications in the vehicles and homes. In this study, demonstrate the multi physics modeling of a proton exchange membrane(PEM) fuel cell with interdigitated flow field design. The model uses current balances, mass balance(Maxwell-Stefan diffusion for reactant, water and nitrogen gas) and momentum balance(gas flow) to simulate the PEM fuel cell behavior.

• Journal of Hydrogen and New Energy
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• v.17 no.2
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• pp.218-226
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• 2006

It can be obtained from hydrocarbon and water, specially production of hydrogen from natural gas is most commercial and economical process among the hydrogen production methods, and has been used widely. However, conventional hydrogen production methods are dependent on fossil fuel such as natural gas and coal, and it may be faced with problems such as exhaustion of fossil fuels, production of greenhouse gas and increase of feedstock price. Thermochemical hydrogen production by nuclear energy has potential to efficiently produce large quantities of hydrogen without producing greenhouse gases. However, nuclear hydrogen must be economical comparing with conventional hydrogen production method. Therefore, hydrogen production cost was analyzed and estimated for nuclear hydrogen as well as conventional hydrogen production such as natural gas reforming and coal gasification in various range.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.509-512
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• 1999

The main problem in porcelain as a high voltage insulator is that the water film is felled on the insulator surface due to rain, flog, and dew. In the presence of contamination. leakage current increases which may lead to flashover that could be followed by an outage of the power system. These days, high voltage polymer outdoer insulators have been studied and widely used, because they have excellent electrical and mechanical properties, superior performance of flashover for contamination. light weight, easy installation or handling. no maintenance during service, competitive price, and so on. First of a1l the excellent performance of the silicone rubber in polluted and wet conditions is attributed to the ability of the material to maintain the hydrophobicity of the surface in the presence of severe contaminants and wet conditions. This is due to a low surface energy of the silicone rubber. But the leakage current and some surface discharge occurs on the surface of insulator when the insulator is used for a long time. So the leakage current and the surface discharge current are important lo estimate the condition of the silicone rubber surface. In this paper, the average leakage current the surface discharge current the surface rubber surface with the salt fog condition for the first stage.

• The Korean Journal of Health Service Management
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• v.3 no.1
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• pp.78-90
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• 2009

The purpose of this study is to propose ways of promoting medical tourism in Busan. For the purpose, this researcher made a questionnaire survey of Japanese tourists who used in Busan International Ferry Terminal between January and April 30, 2008. Findings of the study can be summarized as follows. 86.3% of all respondents had never experienced any medical service in Korea. 57.3% said that the most important thing is the level of medical technology. Most of respondents preferred massage treatment using spa and sea water, followed by Oriental medical services. To make medical conditions(price competitiveness, high-level medical technology, high-quality medical facilities) of Busan properly informed to the outside, it is required to make the city itself more internationally recognized through public relations and strengthening individual medical services provided in the city. It is also required to build up a non-stop service system that helps foreign tourists not only easily use medical institutions, but also better cope with a variety of problems that they might face during stay in the city. To be more trustable to foreign patients, medical services of Busan should be certified by JCI. Furthermore, it is very much needed to develop products which connect medicine with tourism, for example, such programs that combine medical services, tourism, recreation and leisure.