• 지역연구
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• 제36권1호
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• pp.37-50
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• 2020

이 연구는 투자이론에서 활용되고 있는 토빈의 Q 개념을 적용하여 투자이익을 측정하고 이를 통해 서울 주택시장을 이해하고자 한다. 구체적으로 서울시 아파트와 연립·다세대주택을 대상으로 2010년부터 2018년까지 투자이익을 추정하고 공간계량모형을 이용하여 투자이익에 영향을 주는 요인들을 살펴보았다. 투자이익은 실거래가격에서 대체비용(토지비용+건축비용)을 빼는 방식과 실거래가격 대비 대체비용의 비율로 각각 추정하였다. 분석결과를 보면, 투자이익은 2018년으로 갈수록 더 커졌고 강남·서초구 및 한강 주변에서 투자이익이 높게 나타났으나 투자이익의 시공간적 변화양상은 아파트의 경우 뚜렷한 반면에 연립·다세대주택은 산발적·국지적으로 나타났다. 공간계량모형 분석결과는 주택유형과 상관없이 고밀·신축개발이 많은 지역에서 투자이익이 높았다. 이 연구의 접근방법과 결과는 향후 주택 공급 정책, 투자이익 환수, 지역 경쟁력 측정, 가격 거품 측정 등에 대한 논의를 위한 기초 자료가 될 것이다.

• 한국식품영양학회지
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• 제29권5호
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• pp.643-654
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• 2016

The purpose of this study was to investigate the purchasing behavior and selection attributes for Home Meal Replacement (HMR) and to identify the selection attributes affecting purchasing frequency and purchasing costs of married women living in a city. Among 837 questionnaires distributed to HMR married women consumers, 752 complete questionnaires (89.8%) were analyzed. The younger married women group showed higher frequency of purchasing HMR than the older age group. The 20s and 30s age groups showed higher purchasing costs for HMR than the 40s and older age groups. A higher proportion of employed married women purchased HMR three or more times per week and spent an average of more than 20,000 won per purchase in comparison with unemployed married women. HMR selection attributes were classified into five factors: 'taste and sanitation', 'economic efficiency', 'health and nutrition', 'convenience', and 'reliability and awareness'; mean scores of these factors' importance levels were 4.28, 3.93, 3.59, 3.54, and 3.50 out of 5 points, respectively. The importance level of 'taste and sanitation' factor was significantly greater as married women's age decreased. However, the importance level of 'health and nutrition' factor was significantly greater as married women's age increased. The results of the logistic regression analyses indicate that the 'taste and sanitation' and 'health and nutrition' factors affected frequency of purchasing HMR. The 'reliability and awareness' factor had the most significant impact on cost per purchasing HMR. Therefore, a product differentiation strategy according to married women's age and employment status should be applied. Product qualities and brand value should be improved to enhance competition in the HMR market.

• 농업과학연구
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• 제39권2호
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• pp.227-242
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• 2012

Accurate estimation of milk production cost is very important for dairy farmers in establishing strategies for business management (e.g. planning a program for milk production, deciding the size of business and investment, determining the milk price for sale). Since the estimated cost of milk production is used as an important index to determine the basal price of milk in Korea, there has been much interest and debate on the method used to estimate milk production cost among the stakeholder. This study was thus carried out to identify problems in the current methodology for estimating cost of milk production, and to find a better way to improve it. We propose several alternatives and better ways to improve the current method for estimating cost of milk production. Estimation of the income and cost per head should be based on the number of cattle converted to grown cows. Cost estimation per liter of milk should be made for both whole milk and 3.4% milk fat corrected milk. The value of purchased cows and raised replacement heifers should be the same as their market value. The productive life span of cows should be less 4 years, and the terminal or salvage value of cows needs to be 30 to 40% less than her initial value. When calculating depreciation of cows over the productive life span, however, the salvage value should be 0 or 1 Korean won. On calculating labor costs, the farm labor wage corresponding to the average wage of nonfarm industrial workers should be assumed. Beside of these, better estimation procedures for other items are also given. The proposed methods from this study should improve the accuracy of estimation of milk production cost and help to achieve consensus among the stakeholder.

• Computers and Concrete
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• 제21권4호
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• pp.377-384
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• 2018

The accelerated increase of the population growth rate in the world and the current lifestyle based on consumerism considerably increased the amount of waste generated by the human activity. Specifically, e-plastic waste causes significant damage to the environment because of its difficult degradation process. This paper aims to establish the feasibility of using e-plastic waste in concrete as a partial replacement of coarse mineral aggregate. Considering a control mix without e-plastic waste designed for a compressive strength of 21 MPa, tests on concrete mixes with 40, 50 and 60% of e-plastic waste aggregate to determine the fresh and hardened properties were carried out. A reduction in the compressive strength as the percentage of e-plastic waste increases was observed, the maximum reduction being 44% with respect to the control mix. In addition, a significant reduction as much as 22% in the density of the concrete mixes with e-plastic waste was recorded, which means that lighter elements can be produced with this type of concrete. Two new equations based on regression analysis of the experimental data from this study were proposed. These equations estimate the reduction in the compressive strength of concrete mixes with e-plastic waste aggregate at 14 and 28 days. A cost analysis and a practical alternative to introduce this waste material into the market are also presented.

• Journal of Animal Science and Technology
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• 제62권2호
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• pp.111-120
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• 2020

The definition of meat analog refers to the replacement of the main ingredient with other than meat. It also called a meat substitute, meat alternatives, fake or mock meat, and imitation meat. The increased importance of meat analog in the current trend is due to the health awareness among consumers in their diet and for a better future environment. The factors that lead to this shift is due to low fat and calorie foods intake, flexitarians, animal disease, natural resources depletion, and to reduce greenhouse gas emission. Currently, available marketed meat analog products are plant-based meat in which the quality (i.e., texture and taste) are similar to the conventional meat. The ingredients used are mainly soy proteins with novel ingredients added, such as mycoprotein and soy leghemoglobin. However, plant-based meat is sold primarily in Western countries. Asian countries also will become a potential market in the near future due to growing interest in this product. With the current advance technology, lab-grown meat with no livestock raising or known as cultured meat will be expected to boost the food market in the future. Also, insect-based products will be promising to be the next protein resource for human food. Nevertheless, other than acceptability, cost-effective, reliable production, and consistent quality towards those products, product safety is the top priority. Therefore, the regulatory frameworks need to be developed alongside.

• KEPCO Journal on Electric Power and Energy
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• 제3권2호
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• pp.113-117
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• 2017

As the competition in the manufacturing market for small and medium sized generators is intensifying, there is increasing pressure to reduce production cost. Manufacturing the generator stator windings with global vacuum pressure impregnation (GVPI) is a very effective way to reduce costs. However, the stator winding has a fatal disadvantage in that the insulation wears due to vibration in the slot. KEPRI (KEPCO Research Institute) conducted insulation diagnosis for three generators in KOMIPO (Korea Midland Power Co., Ltd.) which were manufactured by GVPI and operated for about 17 years. Insulation diagnosis showed that deterioration of insulation has progressed significantly. Therefore, KEPRI recommended replacing the stator windings of all three generators. In this paper, the insulation properties of the generator stator winding with global GVPI are described by comparing and analyzing the insulation diagnosis results and visual inspection for stator windings.

• 한국자동차공학회논문집
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• 제10권5호
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• pp.199-205
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• 2002

The scale of repair parts market reached 0.1 billion won. Above all, it is remarkable that the automotive insurance business world is paying f3r 40 ~5o% of the whole repair cost. The repair parts consist of a genuine parts, non-genuine parts, recycling used parts. It is the recent trend that recycled parts are more popular than the genuine parts f3r repairing crashed cars due to the cost. Performance of recycled continuous velocity(CV) joints and power steering(PS) gear box as replacement parts was tested and analysed in this study. To examine the durability of the recycled parts, the replaced CV joints and PS gear box after repair were tested and analysed periodically. The results were showed that basic performance of the recycled parts was normal. However the ball cage of CV joints was more frequently damaged than genuine parts. We concluded that a test standard and amendment of related laws for recycled parts is required to get a safe and durable parts.

• Journal of Microbiology and Biotechnology
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• 제31권2호
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• pp.338-347
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• 2021

Polyhydroxyalkanoates (PHA) are a family of microbial polyesters that are used as biodegradable plastics in replacement of conventional plastics for various applications. However, the high production cost is the barrier for PHA market expansion. This study aimed to utilize food waste as low-cost feedstock to produce poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) by Haloferax mediterranei. The effects of acetate (Ac), propionate (Pr), butyrate (Bu), and the short-chain carboxylates derived from food waste were examined on the microbial growth and PHBV production. Results showed that a mixture of carboxylates provided a 55% higher PHBV yield than glucose. The food-waste-derived nutrients achieved the yields of 0.41 to 0.54 g PHBV/g Ac from initial loadings of 450 mg/l to 1,800 mg/l Ac of total carboxylates. And the consumption of individual carboxylate varied between different compositions of the carbon source. The present study demonstrates the potential of using food waste as feedstock to produce PHBV by Haloferax mediterranei, which can provide economic benefits to the current PHA industry. Meanwhile, it will also help promote organic waste reduction in landfills and waste management in general.

• 한국산학기술학회논문지
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• 제10권6호
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• pp.1346-1352
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• 2009

자동차 부품의 품질보증 비용은 각 시장의 품질보증 영역(warranty region) 내에서 부품이 고장 날 확률에 따라 달라진다. 부품이 고장 날 확률은 각 시장의 다른 스트레스 조건이 비슷하다고 가정할 때 사용비율(usage-rate)에 영향을 크게 받는다. 그러므로 품질보증 비용은 사용비율을 반영한 고장모형을 수립하고 이를 이용한 확률과정 (stochastic process)을 통하여 예측할 수 있다. 본 논문에서는 사용비율을 선형으로 가정한 후 가속실험 모형을 적용하여 2차원 고장모형을 1차원으로 축소시킨다. 이렇게 1차원으로 축소된 고장모형은 사용비율의 함수로 표현될 수 있으므로 사용비율의 변동에 따른 부품의 고장확률 변동을 설명할 수 있다. 이를 통해 새로운 시장의 사용비율을 알면 실측 데이터가 없다고 하더라도 고장확률 분포를 추정할 수 있고 교체되어야 하는 부품일 경우 재생과정(renewal process)으로 비용을 예측할 수 있다. 응용사례에서 실제 두 시장의 품질보증 데이터를 이용하여 이를 분석해 보았다.

• 한국정보과학회논문지:데이타베이스
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• 제27권1호
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• pp.53-63
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• 2000

최근 저가의 무선 통신 기술의 발달과 고성능 이동 컴퓨팅 장비의 보급에 따라 이동 컴퓨팅 시장은 점차로 확대되는 추세에 있다. 이동 컴퓨팅 환경에서의 제한된 대역폭， 잦은 단절과 배터리 제한 등의 제약성에 효율적으로 대처하기 위하여 여러 방법이 제안되었고, 특히 지구국에서 전송된 데이타 중 향후 사용 가능성이 높은 데이타를 캐쉬에 저장하고 이용하는 캐쉬 기법에 대한 많은 연구가 이루어지고 있다. 그러나 기존의 캐쉬 교체 기법들은 사용자의 이동성과 데이타의 공간 속성에 의한 특성을 고려하지 못하고 있기 때문에 그 효율성에서 한계를 가지고 있다. 본 논문은 이동 호스트의 위치 변화에 따라 이동 호스트의 캐쉬 내에 저장된 데이타의 가치와 의미가 변경되는 것을 보인다. 또한 지리(geographic) 데이타의 공간적 위치(location)와 지리 데이타가 영향을 미치는 공간적 범위 즉 영역 (region)을 데이타의 공간 속성 (spatial attributes)으로 정의하고, 시간에 따른 사용자의 이동성과 데이타의 공간 속성을 효과적으로 지원하는 새로운 캐쉬 교체 방법들을 제안하였다. 기존의 방법과 본 논문에서 제안한 캐쉬 교체 방법의 비교를 통하여 이동 호스트의 위치와 연관된 질의에 대한 성능 평가를 수행한 결과, 본 논문에서 제안한 캐쉬 교체 방법에 의한 캐쉬 적중률의 향상을 입증하였다. 또한 데이타 밀집도에 따라 캐쉬 교체 방법들의 성능이 변화함을 밝히고 이를 이용하여 이동 호스트가 지나가는 대상 지역의 데이타 밀집도에 따라 서로 다른 캐쉬 교체 방법의 선택이 필요함을 제시 하였다.