• Journal of Technologic Dentistry
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• v.25 no.1
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• pp.143-159
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• 2003

In this study, the data and the Statistical Annual Report of the Korean Dental Technology Association and the yearbook of Health-Welfare Ministry from 1990 to 2002 were surveyed to study and analyze the yearly increase rate and regional distribution rate of the national dental laboratories and dental clinics, the rate of dental laboratories to dental clinics. The purpose of the thesis is to help dental technicians to open the rational and effective dental laboratory which considers the regional condition and the distribution of dental clinics. The result of the study is as follows; 1) The yearly increase rate of overall dental laboratories is 2.01 times to 2002 by the criteria of 1990. The most laboratories was increased in 1995(+94) but the least laboratories was increased in 2000(+13). According to the regional increase rate, Kyounggi Association showed the highest increase rate (7.00 times) but Woolsan Association showed the least increase rate (1.45 times) for the past 5 years. Busan Association had increased by 1.47 times by the criteria of 1990. 2) According to the regional distribution rate of dental laboratories, Seoul area showed the highest distribution rate from the minimum 26.72%(in 2002) to the maximum 35.23%(in 1990) every year, and before 1993, Busan area showed the high distribution rate of 12.49% and Daegu area 12.38%. 3) In the case of the national increase rate, dental clinics had increased by 2.01 times to 2001 by the criteria of 1990 and dental laboratories, whose number was 1,482 in 2002, had increased by 2.01 times to that year. The rate of the national dental laboratories to dental clinics went up an average of 1: 7.57 for 12 years. In 1994, the rate showed the highest 1:7.91 and in 1990, the rate showed the least 1:7.17. 4) The metropolitan rate of dental laboratories to dental clinics showed the average of 1:6.70 for 12 years, and the rate was highest in 1992(1:7.15) and the rate lowest in 1999(1:6.33). 5) The rate of dental laboratories to dental clinics in other areas was 1:9.53, the average of 12 years and was highest in 1991(1:9.97) and was lowest in 1990(1:8.79). (6) The rate of the Korean dental laboratories to dental clinics was 1:7.37 in 2001, the metropolitan rate was 1:6.53 and the rate in other areas was 1:9.10. According to the regional distribution rate, the rate of Kyounggi was highest (1:15.58) and the rate of Daegu was lowest(1:3.03).

• New & Renewable Energy
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• v.9 no.1
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• pp.33-43
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• 2013

The objective of this paper is to provide a review on the latest development on the main initiative and approaches for the sustainability criteria for biofuels. A large number of national and international initiative lately experienced rapid development in the review of the biofuels targets announced in the European Union (EU), United States (US) and other countries worldwide. The global biofuel targets are likely to have a strong impact on land use and agricultural markets. Although biofuels production provides new options for using agricultural crops, there are environmental, social and economic concerns associated with biofuel production. The diversity of feedstock, large number of biofuels pathway an their complexity lead to a high uncertainty over the greenhouse gas (GHG) performances of biofuels, in terms of GHG emission reductions compared to the fossil fuels, expecially if land use change is involved. This paper describes an overview of current status of ongoing certification initiative in Europe and worldwide for biofuels sustainability. It also provides mandatory requirements as part of an sustainability scheme in EU, United Kingdom, US and international approaches and should be reviewed to introduce based on global trends in Korea.

• Journal of Mechanical Science and Technology
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• v.15 no.7
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• pp.941-950
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• 2001

A study of counter-current two-phase flow in narrow rectangular channels has been performed. Two-phase flow regimes were experimentally investigated in a 760mm long and 100mm wide test section with 2.0 and 5.0mm gap widths. The resulting flow regime maps were compared with the existing transition criteria. The experimental data and the transition criteria of the models showed relatively good agreement. However, the discrepancies between the experimental data and the model predictions of the flow regime transition become pronounced as the gap width increased. As the gap width increased the transition gas superficial velocities increased. The critical void fraction for the bubbly-to-slug transition was observed to be about 0.25. The two-phase distribution parameter for the slug flow was larger for the narrower channel. The uncertainties in the distribution parameter could lead to a disagreement in slug-to-churn transition between the experimental findings and the transition criteria. For the transition from churn to annular flow the effect of liquid superficial velocity was found to be insignificant.

• Journal of Distribution Science
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• v.17 no.9
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• pp.25-33
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• 2019

Purpose - The purpose of the study was to seek to find out what factors having differences between paid membership customers (Costco membership) and general customers in retail industry. Since Costco operates differently from other conventional retailers, which is expected to have a substantial impact on consumers' preference of retail stores. Research design, data, and methodology - The survey conducted covered 1,000 adults in their 30s~50s living in Goyang and Gwangmyeong where Costco runs stores to determine the effects of Costco's local market-entry from consumer perspectives. 500 respondents were surveyed in each region and those working in the retail sector were excluded to ensure the objectivity of the answers. Results - Costco members in Goyang considered the price, bulk purchasing, and membership benefits as important criteria when choosing their retail store. On the other hand, as for Gwangmyeong, the non-member group's prominent characteristic was that they considered accessibility including travel distance and location and in-store amenities including food court services as important criteria for decision-making. Conclusion - Unique business model of Costco shows a statistically significant difference in terms of consumer awareness. the feature of Costco served as an critical criteria for consumers in their purchasing decision. Moreover, Bulk packaging purchases at Costco results in a strong supplementary relationship with neighborhood supermarkets.

• Journal of the Korean GEO-environmental Society
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• v.18 no.12
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• pp.37-45
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• 2017

Structural instability and damage are caused by frost heave during the winter when atmospheric temperature maintains below $0^{\circ}C$. Frost heave is the most representative engineering characteristics of frozen ground and there are various frost susceptibility criteria. Frost susceptibility criteria can be roughly divided into three categories. First, frost susceptibility is determined from particle size distribution, which is practically useful and many countries are adopting. In this paper, several particle size distributions (PSDs) are applied to the frost susceptibility criteria but PSD seems to be not enough to determine whether soils are frost susceptible. Second, it is judged from laboratory frost heave testing results. Laboratory frost heave tests were performed with newly developed thermal controlled triaxial cell and the reliability of frost susceptibility criteria is evaluated. New testing apparatus and method are suitable to meet the existing frost susceptibility criteria. Third, it is compositive frost susceptibility criteria envelope including the particle size distribution, soil classification, and frost heave test. The compositive frost susceptibility criteria envelope should be supplemented based on additional data on various soil types.

• Journal of Korean Society of Water and Wastewater
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• v.35 no.6
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• pp.517-531
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• 2021

The water supply facilities of Korea have achieved a rapid growth, along with the other social infrastructures consisting a city, due to the phenomenon of urbanization according to economic development. Meanwhile, the level of water supply service demanded by consumer is also steadily getting higher in keeping with economic growth. However, as an adverse effect of rapid growth, the quantity of aged water supply pipes are increasing rapidly, Bursts caused by pipe aging brought about an enormous economic loss of about 6,161 billion won as of 2019. These problems are not only worsening water supply management, also increasing the regional gap in water supply services. The purpose of this study is to classify hazard evaluation indicators and to rank the water distribution network hazard by cluster using the TOPSIS method. In conclusion, in this study, the entropy-based multi-criteria decision-making methods was applied to rank the hazard management of the water distribution network, and the hazard management ranking for each cluster according to the water supply conditions of the county-level municipalities was determined according to the evaluation indicators of water outage, water leakage, and pipe aging. As such, the hazard ranking method proposed in this study can consider various factors that can impede the tap water supply service in the water distribution network from a macroscopic point of view, and it can be reflected in evaluating the degree of hazard management of the water distribution network from a preventive point of view. Also, it can be utilized in the implementation of the maintenance plan and water distribution network management project considering the equity of water supply service and the stability of service supply.

• Journal of Korea Trade
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• v.24 no.3
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• pp.20-36
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• 2020

Purpose - As the global product network expands through both internationalization and diversification of the multimodal transportation system, corporate strategies have shifted to emphasize the importance of a high value-added international logistics system. To guide policies and strategies to attract relevant industries, this study aims to analyze the location competitiveness of regional logistics distribution center to serve Northeast Asia. Design/methodology - Multi-criteria techniques are considered to offer a promising framework for evaluating decision-making factors. This paper employed an analytic hierarchy process to analyze the hierarchal structure of determinants for selecting the location of a regional logistics distribution center. Adopting both qualitative and quantitative evaluations, this study suggest political implications for a regional logistics distribution center development, such as the direction of political support, service differentiation and infrastructure development. Findings - This study developed a location competitiveness evaluation model, based on the case study of the major port-cities in Northeast Asia. Evaluation model incorporates five factors underpinning 17 components extracted using factor analysis. The results revealed that the logistics factor is the most significant factor for evaluating the competitiveness of a regional logistics distribution center. The remaining factors were market, costs, and services environment. Comparing qualitative and quantitative evaluations, results provide useful insights for a regional logistics distribution center development in Northeast Asia. Originality/value - This study revealed differences between qualitative and quantitative evaluations. The finding implies that prior works on evaluation models of competitiveness has not successfully measured the gap between quantitative data and expert' evaluations. To overcome this limitation, this paper considered both actual data such as actual distance, cost, the number of companies located, and expert opinions.

• The Korean Journal of Applied Statistics
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• v.7 no.1
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• pp.131-140
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• 1994

In order to find the identification function from data and to apply the identification function for the pattern classification, we consider the existing problem of the number of patterns in such data. In this paper, a new criteria for the identification of Gaussaian mixture distribution could be established as a charateristic of the sample variance, which is a bootstrap estimate of the sample variance. We examine the properties and fittness of the criteria through a large scale of computer simulations.

• Journal of Distribution Science
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• v.11 no.6
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• pp.21-30
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• 2013

Purpose - This paper examines product design management, the current design focus of which has shifted to the need to produce innovation applications that can effectively respond to the market's consumption changes in a timely manner. Research design, data, methodology - This study discusses several methodologies that are widely used in experimental processes, such as fuzzy theory, multi-criteria decision-making theory, and managing decision making. The designers will better understand their customers by applying these methodologies. This study examines how the current trend in product innovation design observes customer needs, controls innovation, and stimulates design ability. Results - This paper takes innovative telephone design as an experimental case to investigate how to create a product using market-oriented and customized management concepts and creative design abilities. Conclusions - If accompanied by an innovative product value chain, a product can further the development of enterprise management, now the main element of every developed country's social and economic development.

• Transactions of Materials Processing
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• v.13 no.8
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• pp.671-677
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• 2004

For the large reduction in tube cross section, the tube drawing process is usually performed by two successive passes, so called first drawing and second drawing. In multi-pass drawing process, the reduction balance is important to prevent drawing cracks. Therefore in this study, the model for uniform reduction distribution in two-pass drawing process has been developed on the basis of cross sectional variation of drawn tube. For the given product geometry the model provides optimal diameter and thickness that can evenly distribute drawing reductions. The capability of model is well confirmed by finite element analysis of tube drawing process. Criteria curves at various limit strains to determine whether the drawn tube would fail during drawing process are also proposed by using newly developed model.