• Environmental and Resource Economics Review
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• v.15 no.4
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• pp.673-692
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• 2006

In order to test for the dynamic optimality condition for the use of nonrenewable resource, it is necessary to estimate the shadow value of the resource in situ. In the previous literatures, a time series for in situ price has been derived either as the difference between marginal revenue and marginal cost or by differentiating with respect to the quantity of ore extracted the restricted cost function in which the quantity of ore is quasi-fixed. However, not only inconsistent estimates are likely to be generated due to the nonmalleability of capital, but the estimate of marginal revenue will be affected by market power. Since firms will likely fail to minimize the cost of the reproducible inputs subject to market prices under realistic circumstances where imperfect factor markets, strikes, or government regulations are present, the shadow in situ values obtained by estimating the restricted cost function can be biased. This paper provides a valid methodology for checking the dynamic optimality condition for a nonrenewable resource by using the input distance function. Our methodology has some advantages over previous ones: only data on quantities of inputs and outputs are required; nor is the maintained hypothesis of cost minimization required; adoption of linear programming enables us to circumvent autocorrelated errors problem caused by use of time series or panel data. The dynamic optimality condition for domestic coal mining does not hold for constant discount rates ranging from 2 to 20 percent over the period 1970~1993. The dynamic optimality condition also does not hold for variable rates ranging from fourth to four times the real interest rate.

• Journal of the Korea Society of Computer and Information
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• v.16 no.7
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• pp.13-23
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• 2011

Grid computing is a new generation computing technology which organizes virtual high-performance computing system by connecting and sharing geographically distributed heterogeneous resources, and performing large-scaled computing operations. In order to maximize the performance of grid computing, job scheduling is essential which allocates jobs to resources effectively. Many studies have been performed which minimize total completion times, etc. However, resource costs are also important, and through the minimization of resource costs, the overall performance of grid computing and economic efficiency will be improved. So in this paper, we propose a multi-objective job scheduling model considering both time and cost. This model derives from the optimal scheduling solution using NSGA-II, which is a multi objective genetic algorithm, and guarantees the effectiveness of the proposed model by executing experiments with those of existing scheduling models such as Min-Min and Max-Min models. Through experiments, we prove that the proposed scheduling model minimizes time and cost more efficiently than existing scheduling models.

• Proceedings of the Korea Information Processing Society Conference
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• 2010.11a
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• pp.1065-1067
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• 2010

실제 무선센서네트워크 환경에서 무선링크는 일반적으로 발생하는 간섭, 감쇠, 멀티패스 등으로 인해 비신뢰성과 비대칭성을 가진다. 기존에 제안된 위치기반라우팅기법들은 이러한 무선링크의 특성을 고려하지 않아, 데이터 전송 성공률과 에너지 효율이 떨어지는 문제를 가진다. 본 논문에서는 무선링크의 비신뢰성과 비대칭성 그리고 거리 값을 고려한 기대전송비용(EC)을 정의하고, 데이터와 ACK 패킷 각각에 대해 예상전송비용이 최소인 경로를 찾아 에너지 효율적인 전송을 한다. 이러한 방법을 통해 센서노드의 제한된 베터리 자원을 효율적으로 사용하고, 네트워크 라이프타임을 증가시킨다.

• Journal of Korean Society of Transportation
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• v.9 no.2
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• pp.87-100
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• 1991

1960년 초부터 토지이용과 교통의 상관관계를 계량적으로 설명하고자 하는 연구가 진행되어 왔다. 이러한 연구는 경제이론을 배경으로 하여 개발된 McKinnon-Type 모형과 Mills-Type 모형, 그리고 경제학이 반영되어있지 않은 Lowry-Type 모형으로 크게 대별할 수 있다. 이제까지의 이러한 연구는 각 가정의 주거입지선정과 직장선정에 있어서 취향의 다양성(taste heterogeneity)을 고려하여 있지않고 있어 본 연구에서는 로짓모형을 이용하여 Alonso(1964) 모형을 더욱 발전시켜 토지이용-교통의 일반균형 모형(general equilibrium model)을 개발하였다. 이 통계적 토지이용-교통모형은 완전 경쟁하의 일반균형상태에서 주택임대료, 노동력임금, 상품가격이 내생적으로 산출되어지며, 동시에 효율적인 교통체계하에서 일반균형상태의 생산량과 생산부지 그리고 주거수와 주거부지가 어떻게 분배되는지를 내생적으로 결정한다. 이논문에서 효율적인 교통체계라함은 해당 죤에서 도로에 사용된 토지의 임대료가 교통체증비용의 전통행량에 대한 합과 동일하도록 하는 최적교통체증정도(optimal congestion level)을 유지할 수 있는 도로체계를 뜻한다. 또한 비효율적 교통체계하에서는 토지 이용에 왜곡이 생겨서 전체적 비용의 상승으로 각 국민 혹은 각 주민이 생활에서 얻을 수 있는 효용가치가 떨어짐을 분석할 수도 있다.

• Proceedings of the Korean Information Science Society Conference
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• 2005.11b
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• pp.445-447
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• 2005

연구비카드시스템개발 시 사용자의 개발요구사항 적용에 있어 구조적 방법론 사용시 기존시스템 개발만큼의 소요시간 및 개발비용이 동일하게 적용되므로 이에 시간적, 비용적측면의 개선이 불가피하다. 이에 대해 컴포넌트 기반 개발방법론으로의 변경으로 공통적인 분석사항 및 설계에 대해 개발방법론상의 단일한 패턴을 적용시킴으로써 개발비용절감과 컴포넌트 재사용으로 개발의 효율성을 증대시키는 효과를 가져올 수 있는 장점에 대해 연구해 본다.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2002.07a
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• pp.310-315
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• 2002

겨울철 저온기에 온실의 작물재배는 많은 에너지가 소요되어 저온기의 에너지비용을 최소화하는 것이 온실의 운전비용의 절감과 이용효율이 증대되어 농가소득을 높일 수 있다. 저온기에는 작물의 수확량이 적정 온도조건의 80%수준으로 최소 에너지 투입방법 기술을 개발하여 수확량을 증대시킬 필요가 있다. 기존의 난방방법인 온수보일러는 온도유지 안정성은 좋으나 시설비용이 많이 들고 온풍난방은 설치비용은 저렴하나 온도 유지안정성이 다소 떨어지는 단점이 있다. (중략)

• Journal of the Korea Convergence Society
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• v.4 no.2
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• pp.15-20
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• 2013

This study aims to determine factors related for manufacturers to use distributors storehouse and its cost efficiency in Supply Chain. When manufacturers which have relationships with Big distributors determine the way of their logistics, they can use their own warehouse, or the distributors', or outsource its function. In which case the manufacturers face the cost efficiency of using warehouse will be different, therefore, the driven factors will exist internally or externally. The findings of this study are that internal factors(brand value, product portfolio, and technological capabilities), external factors(technological characteristics, demands fluctuations, and munificence), and transaction characteristics(transaction experiences, dependency) would be driven factor between manufacturer and distributors in supply chain. These driven factors effects manufacturers transactions power on their distributors.

• The Journal of the Korea Contents Association
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• v.3 no.4
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• pp.63-68
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• 2003

This paper is to measure the sensitivity of relations in communication network operation. In order to procure an important adequacy in the network operation and quality improvement, it is necessary to increase network operation efficiency and analyze the characteristic of network operation. Finally, we analyze costing appropriate operation, propose profit increase scheme and apply realistic business. First of all it's important to improve and estimate a proper operating cost thoroughly and comprehensively. Because the important issue of this process is quality process and this quality process occurs customers' satisfaction, therefore, to make a mutual relation in-between individual change of each element is to analyze a reasonable standard. So, for this reason we study on structuring nice moods for network operation and estimating many scenarios for measuring efficiency. Especially those in economic and sensitivity based. It will be the development of analyzing methods which suites the service and communication system. The result of this study gives a basis for making a flexible and highly predictable system by pre configured sensitivity analysis of each scenarios.

• The Journal of Engineering Geology
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• v.19 no.3
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• pp.307-311
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• 2009

Agricultural is recognised as being the leading contributor to groundwater. As a consequence, the consumer have to has bear the high expenses of water supplied to be treated. Importantly, the cost of water supplied is a function of the water quality as well as the scale of drinking water treatments. The relationship between the consumer payment and water quality improvement was affected by the scale of drinking water treatments directly. Hence when we achieve the high quality and low cost in the case of groundwater treatment for drinking, it is needed to consider both water quality and plant scale.

• Journal of Food Hygiene and Safety
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• v.13 no.3
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• pp.299-304
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• 1998

From 1993 to 1996, 1,500 cases of foodborne disease was reported annually in Korea. Salmonellosis were 55.1% of the reported bacterial fordborne disease cases. However, in general, it is estimated that the reported incidence of salmonellosis represents less than the real incidence. This study showed that salmonellosis estimates 177,000 cases (about 150 times of reported cases) costing 5.9 billion won in Korea. Only medical costs and productivity losses were included in the estimate of costs of the 177,000 cases estimated to occur in 1996. This estimates were considerably difference to U.S.A. in cases and costs, but not significantly difference in cases/population (%), expense/GDP (%). Understanding the social economic costs of foodborne disease will be endorsed risk assessment as a necessary method for evaluation and improving food safety regulatory programs in Korea.