• 한국안전학회지
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• 제16권4호
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• pp.22-28
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• 2001

Heat transfer and pressure distribution for heat exchanger type of domestic gas boiler are different from shape, pitch, thickness of fin and array of pipe respectively. In order to measure the pressure distribution across the heat exchanger, a suction type wind tunnel was constructed and velocity distribution was measured for pilot tube(4 point) of rack type. The experiments were performed for 5 different air flow mass, rpm=3,6,9,12,15 and transverse axis of heat exchanger(x-length) is 5cm respectively. Results showed that above 9.5m/s, pressure distribution dispersion for wet type of heat exchanger is on the increase and above 5.5m/s, pressure distribution dispersion for dry type of heat exchanger is on the increase. Also, pressure distribution dispersion by comparing two different types heat exchanger, dry type of heat exchanger showed a higher augmentation than wet type of heat exchanger.

• 대한전기학회논문지:전력기술부문A
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• 제52권2호
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• pp.69-78
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• 2003

This paper presents a voltage analysis method of distribution systems interconnected with DG(Distributed Generation). Nowadays, small scale DG becomes to be introduced into power distribution systems. But in that case, it is difficult to properly maintain the terminal voltage of low voltage customers by using only ULTC(Under Load Tap Changer). This paper presents a voltage analysis method of distribution systems with DC for proper voltage regulation of power distribution systems with ULTC. In order to develop the voltage analysis method, distribution system modeling method and advanced loadflow method are proposed. Proposed method has been applied to a 22.9 kV practical power distribution systems.

• 산업공학
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• 제11권2호
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• pp.13-24
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• 1998

A distribution system is composed of multiple levels from a producer to customers, and it's objective is to supply customers with goods timely with a prescribed level of quality at a minimum cost. For the installation and operation of multi-echelon distribution system, DRP(Distribution Resource Planning) is widely used. However, because of the characteristic difference of material flow dynamic of each distribution center, it is almost impossible to get the optimal distribution scheduling. In this paper, an improved DRP method to schedule multi-echelon distribution network is proposed so that the lot-size and order point is dynamically obtained to meet the change of demand rate and timing. The experiment is done with various demand pattern, forecast errors of demand and lead times of central distribution center. The proposed method is compared with traditional statistical approach.

• 한국지구과학회지
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• 제35권7호
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• pp.518-528
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• 2014

본 연구에서는 대관령 지역에서의 광학우적계(PARSIVEL disdrometer) 강수관측으로부터 산출된 강수율에 따른 강수입자분포 자료를 바탕으로 기존의 강수입자분포 모형을 개선하였다. 선행 연구에서 제안한 다양한 강수입자분포 모형과 측정 자료와의 상관성을 분석한 결과, 대관령 지역에 적용 가능한 원형 모형은 개선된 ${\Gamma}$ 분포 모형임을 확인하였다. 원형 모형을 대관령 지역에 적용할 수 있도록, 민감도 실험을 통해 최적의 매개변수들(${\alpha}$, A, B)을 산정하였으며, 다섯 가지 강수율에 대한 강수입자분포 모형을 제안하였다. 강수율에 따른 강수입자분포 모형의 결과는 관측에서 측정된 값과 높은 상관성($R^2=0.975$)을 보였다. 강수율에 따라 표현되는 강수입자분포 모형을 일반화 형태로 개선하기 위해 강수율과 매개변수의 상관성을 도출하여 일반식을 결정하였다. 일반화된 강수입자분포 모형은 대관령 지역의 강수입자분포 측정 자료와 높은 상관성($R^2=0.953$)을 보였으며, 이는 본 연구에서 제안한 모형이 대관령 지역의 강수입자분포를 모의하는데 효과적임을 의미한다. 그러나 본 연구에서 제안된 강수입자분포 모형은 대관령 지역의 강수입자분포에만 최적화 되었다는 한계성이 있어, 따라서 한반도를 대표하는 모형을 개발하기 위해서는 다른 지역에 대한 광범위한 측정이 필요하다.

• 유통과학연구
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• 제11권9호
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• pp.43-49
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• 2013

Purpose - The competitiveness of small- and medium-sized distribution companies has weakened with the entry of large distribution companies and Super Super Markets (SSMs). These companies have nationwide distribution networks and capital to take over street markets, thereby threatening the very survival of small merchants. In order to help these small- and medium-sized merchants, the government has recently reinforced distribution regulations for large distribution companies. Research design, data, methodology - The purpose of this study is to review domestic and foreign distribution regulations and to provide direction for establishing domestic distribution policies in the future. Results - The government must fully reassess its assistance policy for small and medium distribution companies to enable them to engage in differentiated competition with large retailers, based on their own strengths. This will allow all interested parties to coexist. Conclusions - Government assistance policies for small and medium distributors such as traditional markets must be reorganized. The objective is to ultimately protect small and medium distributors and allow them to coexist on their own strengths, rather than have regulations for large retail stores.

• Nuclear Engineering and Technology
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• 제44권7호
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• pp.735-744
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• 2012

In order to quantify the flow distribution characteristics of APR+ reactor, a test was performed on a test facility, ACOP ($\underline{A}$PR+ $\underline{C}$ore Flow & $\underline{P}$ressure Test Facility), having a length scale of 1/5 referring to the prototype plant. The major parameters are core inlet flow and outlet pressure distribution and sectional pressure drops along the major flow path inside reactor vessel. To preserve the flow characteristics of prototype plant, the test facility was designed based on a preservation of major flow path geometry. An Euler number is considered as primary dimensionless parameter, which is conserved with a 1/40.9 of Reynolds number scaling ratio. ACOP simplifies each fuel assembly into a hydraulic simulator having the same axial flow resistance and lateral cross flow characteristics. In order to supply boundary condition to estimate thermal margins of the reactor, the distribution of inlet core flow and core exit pressure were measured in each of 257 fuel assembly simulators. In total, 584 points of static pressure and differential pressures were measured with a limited number of differential pressure transmitters by developing a sequential operation system of valves. In the current study, reactor flow characteristics under the balanced four-cold leg flow conditions at each of the cold legs were quantified, which is a part of the test matrix composing the APR+ flow distribution test program. The final identification of the reactor flow distribution was obtained by ensemble averaging 15 independent test data. The details of the design of the test facility, experiment, and data analysis are included in the current paper.

• 한국의류학회지
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• 제35권5호
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• pp.612-620
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• 2011

This study provides information and suggest a direction for the future research needs of medical attire as a high value-added industry. A total of 69 studies on medical attire were categorized and analyzed for the study subject, study method, and study locations. As per the time period, until the mid-80s, almost no research on medical attire was conducted; however, the number has increased as of late. The distribution by subject was in the order of status investigation, design development, material research, textile design, and sizing system, and especially there was significant focus on wearing status and design development that has rapidly increased over the last 10 years. The distribution by target was in the order of adult patients, elderly patients, doctors, nurses, and juvenile patients. There are many studies on the wearing status and design development of adult patient attire as well as on the textile design and sizing system study for doctor's attire. The distribution by study method was in the order of survey and interview, research and development, dressing evaluation, real resources analysis, and physical property experiments. Through the results of the analysis on the study subject and target, it was found that the wearing status investigation for adult patient attire through a survey and interview was most active. The distribution by study location was in the order of Seoul, Incheon - Gyeonggi, Busan - Ulsan - Gyeongnam, and suggested that a study on patient attire in Dajeon - Chungcheong and Jeonbuk was inadequate.

• Journal of the Korean Statistical Society
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• 제34권4호
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• pp.273-280
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• 2005

In this paper we introduce an estimator of the second order parameter characterizing the tail behavior of probability distributions and prove its consistency.

• 기술혁신학회지
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• 제16권1호
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• pp.41-62
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• 2013

중소기업청에서는 중소기업의 연구개발을 촉진하고 혁신형 중소기업을 육성하기 위해, 정책적 부합성을 우선적으로 고려하여 선정된 중점지원분야를 중심으로 연구개발 자금을 지원하고 있다. 이러한 하향식 중점지원분야 선정의 실효성을 파악하기 위해 각 분야별 종사 중소기업의 분포, 과제 지원 중소기업의 분포, 선정 과제 분포 사이의 상관관계를 분석하였다. 그 결과 종사 중소기업 수와 과제 지원 중소기업 수가 각 분야별로 큰 편차를 보였으며, 선정된 중점지원분야가 중소기업의 기술개발 수요를 정확히 반영하지 못하고 있었다. 또한 지원 중소기업의 분포가 종사 중소기업의 분포에 강한 의존성을 보여, 중소기업들은 주로 정책적 방향에 따르기 보다는 현재 종사하고 있는 사업 분야에서 연구개발을 기획하려는 경향이 있음을 알 수 있었다. 아울러 선정과제 분포가 지원 중소기업 분포에 강한 상관관계를 보여, 중점지원분야들이 전략적으로 고르게 육성되기 보다는 단순히 지원업체의 분포에 따라 지원자금이 배분되고 있는 것을 알 수 있었다. 본 연구에서는 하향식 중점지원분야 선정의 한계를 보완하기 위해, 중소기업의 기술개발 니즈를 우선 반영하는 상향식 중점지원분야 선정 방안을 제안하였다. 상향식 선정 방식에서는 기술개발 수요, 기술개발 역량, 기술성 및 시장성, 정책적 중요도의 순서로 고려되는 것이 바람직하며, 이는 다양한 사업 기획에 더욱 유연하게 활용될 수 있을 것으로 기대된다.

• 유통과학연구
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• 제14권12호
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• pp.71-78
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• 2016

Purpose - This paper is for the Analysis on the Hindrance Factors and Activation Scheme by the Type of Distribution Channel in Direct transaction of Agricultural Products. As the distribution structure of agricultural products has become changable, farmers seem to use the type of direct distribution in order to enhance the receiving price. This study aims to explore the hindrance factors and income variation rate in direct transaction of agricultural produces, specifically focusing on the 167 farmers. Research design, data, and methodology - To ascertain the hindrance factors exactly by the type of distribution channel, the managements were classified by four subcategories, that is high sales percentage with shopping malls, SNS, shopping malls and SNS, and off-line direct transaction. Results - As a result of the hypothesis test, hinderance factors in online direct deal activation were found to be in the order of the difficulty in continuous content production, the difficulty in shopping mall operation and maintenance, and the difficulty in card commission problems, and in the order of the difficulties in continuous content production, the difficulty in continuous content production, the difficulty in shopping mall operation and maintenance, and the difficulty in branding for the SNS group. Thus, it can be seen that the difficulty in continuous content production, shopping mall operation and maintenance were found to be the biggest obstacles. In addition, hindering factors in online direct deal activation were found to be in the order of the difficulty in credit card settlement, the difficulty in publicity, and the difficulty in dealing with unsold goods. The group with high sales rate in shopping mall was found to be increased by 23.9% in the gross income compared to the previous year, the group with high SNS sales ratio increased by 56.5%, the group with direct offline transaction increased by 37.1%, among which the group with the highest increase rate of SNS sales ratio was found to be the highest from the rate of increase/decrease of the income, which was statistically significant. Conclusions - It can be suggested that government and local government may provide agricultural management with supporting plan which in turn can activate direct transaction in any possible ways.