• 가족자원경영과 정책
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• 제9권1호
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• pp.1-15
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• 2005

This study was designrd to determination factors of purchase expansion for environment-friendly agricultural products on consumers. The 310 subjects formatted questionnaires were analyzed to frequency, percentage, descriptives, T-test and logistic regression by SPSS WIN 10.0. The results were as follows : First, it is proved that degree of cognition, standard of information acquisition, basis of valuation were significant variables, Second, it is revealed that the producer and the direct deal, the consumer organization's co-op and the food floor of large-sized discount hoarded goods for purchase places of environment-friendly agricultural products were significant variables. Third, it is proved that reduction in a price the improvement matter for purchase expansion of environment-friendly agricultural products was determination factors. Forth, it is proved that age and income for purchase expansion of environment-friendly agricultural products was determination factors. Accordingly, we should find the positive factors of purchase and consumption that it will become an important subject for environment-friendly agricultural products on consumers.

• 한국재료학회지
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• 제31권11호
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• pp.626-634
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• 2021

Cu matrix composites reinforced with chopped carbon fiber (CF), which is cost effective and can be well dispersed, are fabricated using electroless plating and hot pressing, and the effects of content and alignment of CF on the thermal properties of CF/Cu composites are studied. Thermal conductivity of CF/Cu composite increases with CF content in the in-plane direction, but it decreases above 10% CF; this is due to reduction of thermal diffusivity related with phonon scattering by agglomeration of CF. The coefficient of thermal expansion decreases in the in-plane direction and increases in the through-plane direction as the CF content increases. This is because the coefficient of thermal expansion of the long axis of CF is smaller than that of the Cu matrix, and the coefficient of thermal expansion of its short axis is larger than that of the Cu matrix. The thermal conductivity is greatly influenced by the agglomeration of CF in the CF/Cu composite, whereas the coefficient of thermal expansion is more influenced by the alignment of CF than the aggregation of CF.

• 한국음향학회지
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• 제38권3호
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• pp.344-351
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• 2019

본 연구에서는 수축 및 팽창 소음 발생 메커니즘을 분석하고, 냉장고 운전 중에 소음발생 빈도를 줄이기 위한 효과적인 방법을 제안하였다. 냉장고의 수축팽창음 발생 시에 제품의 품질비용 상승에 영향을 주기 때문에 저감이 필요하다. 먼저, 무향실에서 측정된 음압 신호를 이용하여 주파수 스펙트럼 분석을 수행하여 소음의 특성과 발생 빈도를 분석하였다. 둘째, 열변형 해석을 수행하여 소음원의 위치를 예측했다. 분석결과에서 가장 큰 열변형은 냉동실의 왼쪽 내부 케이스의 중간에서 발생하였다. 또한 음원 위치의 가속도 레벨을 평가한 결과, 소음을 발생시키는 내부 부품이 냉동실의 세 번째 선반임을 알 수 있었다. 냉장고의 중앙 ABS(Acrylonitrile Butadiene Styrene) 두께 증가에 의한 열변형 저감을 통하여 수축팽창음을 저감할 수 있는 방법을 제안하였다.

• 한국추진공학회지
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• 제26권5호
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• pp.11-23
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• 2022

길이를 단축한 ED(Expansion Deflection) 노즐의 설계를 위해 길이 단축 방안에 따른 ED 노즐의 수치적 연구를 수행하였다. 첫 번째 방안은 80% 벨 노즐 길이를 갖는 ED 노즐의 확장부 길이를 10%, 20%와 30%씩 단축하는 것이다. 두 번째 방안은 노즐 목 각도를 증가시켜 확장부 길이를 단축하는 것이다. 길이 단축에 따른 윤곽선의 곡률 증가로 인해 80% 벨 노즐 길이인 ED 노즐과 첫 번째 방안의 ED 노즐의 출구 유동 속도의 감소폭이 줄어들어 추력이 유사해졌다. 두 번째 방안의 ED 노즐은 80% 벨 노즐 길이인 ED 노즐보다 출구 유동 속도가 증가하여 추력이 증가하였다.

• 한국음향학회지
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• 제41권4호
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• pp.389-396
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• 2022

본 논문은 냉장고 수축팽창 소음의 원인 및 메커니즘을 파악하고 소음 감소 방법을 제안한다. 냉장고에서 발생하는 수축팽창 소음은 주로 내부부품 사이의 접촉면에서 발생하는 스틱슬립 현상에 의한 것이다. 스틱슬립 현상을 일으키는 요인을 규명하기 위해 마찰실험이 수행되었다. 또한 내부부품의 진동레벨을 측정하여 수축팽창 소음의 특성 및 위치를 규명하였다. 실험 결과를 바탕으로 요인별 소음 특성을 검증하는 실험이 진행되었다. 이를 통해 마찰실험과 냉장고 수축팽창 소음 발생 위치와 빈도가 동일한 것을 확인하였다. 하중적재로 수직력이 증가하면 진동레벨도 증가하였다. 또한 표면거칠기를 증가하였을 때 수축팽창 소음이 저감되는 것으로 확인되었다. 따라서, 마찰실험 결과와 동일하게 접촉면의 표면거칠기를 증가하는 것이 수축팽창 소음저감 방법이라는 결론을 도출하였다.

• Journal of Information Technology Applications and Management
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• 제11권2호
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• pp.227-237
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• 2004

While the WWW offers an incredibly rich base of information, organized as a hypertext, it does not provide a uniform and efficient way to retrieve specific information. When one tries to find information entering several query terms into a search engine, the highly-ranked pages in the result usually contain many irrelevant or useless pages. The problem is that single-term queries do not contain sufficient information to specify exactly which web pages are needed by the user. The purpose of this paper is to describe the employment of association rules in data mining for developing networks and computing associative coefficient among the terms. And this paper shows how the dynamic query expansion and/or reduction can be performed in information retrieval.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.402-406
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• 2000

In the Over-The-Range, the outlet size is limited by the industrial standards. Therefor to enlarge the volume of cavity, the installation height of ventilation fan is become small, the system resistance is higher than before. For that reason, the important design variables such as the diameter of a fan, the scroll expansion angle, etc. which play the significant role on flow rate and noise, are confined. In this study, we made an experiment of the diameter of fans relation to scroll expansion angle and investigated flow rate of the length of fans in enlarged cavity volume of OTR, and then we designed the new scroll to improve the flow rate and noise level. As a result, flow rate increased to 110% compared to current scroll and the blade passing frequency of a fan is disappeared by inclined cut-off shapes.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.564-565
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• 2008

All over the world, energy environment dramatically changes because of highly oil price, global warming and reduction of greenhouse gas. The power sector is effected directly indirectly by these factors. Especially, the power expansion planning of power sector should adapt itself to new surroundings. This paper presents the new system of the power expansion planning that reflects Genco's needs, power market and variable conditions. This presented system would provide regulator and Gencos with useful information about a power planning.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1990년도 하계학술대회 논문집
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• pp.96-99
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• 1990

Recently, electric energy consumption pattern shows very high peak load with low load factor. This Load pattern have made electric utilities be interested in Load Management, many studies are reported. But most of these studies are concerned with Rate - Load shape relation, a few of these are concerned with generating cost reduction. In this study, the effect of Load Management is incorporated to establish optimal Generation Expansion Planning. Using avoided cost, optimal generation expansion planning is achieved to make maximum avoided cost of Electric utility. Dynamic programming technique is used to solve this algorithm.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 D
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• pp.1083-1087
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• 1997

Every effort is now being exerted in industrialized and developing countries to reduce emission of greenhouse gases from electric power sector. In this paper, we provide supply-side resource mix strategies in the long-term generation expansion planning under the expected greenhouse gas regulations. Under the environmental regulations, we explore the least-cost generation expansion plan of Korea and determine the composition of future resource mixes. Our analysis is performed on the basis of the revised WASP package which can evaluate emission of carbon dioxide from each power plant. The evaluation process of carbon dioxide emissions, which can consider the efficiency and operating conditions of each generator simultaneously, has been incorporated into the probabilistic production cost simulation module of WASP.