• Journal of the Korea Society for Simulation
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• v.18 no.1
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• pp.41-51
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• 2009

A discrete event simulation model is developed to evaluate the performances of three different revenue management methods for an air cargo network from Northeast China to North America and Europe. In the first method, a bid price model is applied only to the routes that pass through Incheon. In the second method, the bid price model is applied to all the routes. In third method, bid price and virtual nesting models are applied to the routes that pass through Incheon. The results show that the total revenue significantly increases with the employment of pricing and capacity control. The developed simulation model is a useful research tool to study marketing strategies for air cargo operations.

• KDI Journal of Economic Policy
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• v.36 no.3
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• pp.61-93
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• 2014

This paper analyzes Onbid car auction data by employing various methods, including structural estimation, to identify main factors which decides auction prices and figure out what effects those factors are making on the auction price. I then discuss on how to maximize sellers' revenue in OnBid car auctions. The government and public institutes sell their assets through the OnBid auction, hence the optimal design of the OnBid auction is important. The paper's main findings are as follows: (ⅰ) The independent private value model explains OnBid car auction data better than the correlated private value model or the interdependent value model; (ⅱ) Both the number of bidders and the ratios of the auction price to the evaluation value were lower in the auctions posted by the Kamco than auctions by institutes other than the Kamco; (ⅲ) Some auctions require that at least two bidders should submit a bid no less than the reserve price for sale. In those auctions, both the number of bidders and each bidder's valuation on the auctioned object were lower than in auctions without that requirement; (ⅳ) The sum of sellers' revenue would be decreased in the simulation with the reserve price higher by 5%, 10%, and 20% across auctions by institutes other than Kamco.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.7
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• pp.1326-1331
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• 2006

Weld root gap is a important fact of a falling-off weld quality in various kind of weld defect. The welding quality can be controlled by monitoring important parameters, such as, the Arc voltage, welding current and welding speed during the welding process. Welding systems use either a vision sensor or an Arc sensor, both of which are unable to control these parameters directly. Therefore, it is difficult to obtain necessary bead geometry without automatically controlling the welding parameters through the sensors. In this paper we propose a novel approach using neural networks for detecting and monitoring of weld root gap and bead shape. Through experiments we demonstrate that the proposed system can be used for real welding processes. The results demonstrate that the system can efficiently estimate the weld bead shape and detect the welding defects.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.11a
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• pp.215-218
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• 2012

스팟 인스턴스(Spot instance)는 클라우드 환경에서 사용자가 제시한 입찰 가격으로 클라우드 내의 자원을 이용하여 작업을 수행할 수 있게 하는 새로운 방식이다. 사용자는 자신의 입찰 금액이 클라우드 내의 스팟 인스턴스 가격을 초과하는 한 인스턴스를 실행할 수 있다. 그러나 입찰 가격이 스팟 가격보다 낮다면 작업 실패가 발생하고, 이로 인해 작업 완료 시간은 지연되며 서비스 품질은 저하된다. 이 문제를 해결하기 위해, 본 논문에서는 스팟 인스턴스에서 사용자 비드가 초과되어 작업 수행이 중지된 VM에 대하여 체크포인트 기법과 VM 이주(migration) 기법을 이용함으로써 작업 대기 시간을 줄이는 방법을 제안한다. 이는 작업 중인 스팟 인스턴스에서 작업 실패가 발생할 경우 다른 인스턴스로 이주하여 작업을 재수행하는 기법이다. 실험 결과는 제안하는 VM 이주 기법이 작업을 수행할 수 있는 스팟 인스턴스의 가용성을 증가시킬 수 있음을 보여준다.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2010.10a
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• pp.291-294
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• 2010

EPS 샌드위치 패널은 화재 시 치명적인 단점을 가지고 있다. 하지만 여전히 EPS 샌드위치 패널이 국내에 많이 사용되는 이유는 가격이나 시공성, 생산성에서 EPS를 대체할만한 물질이 아직 개발되지 않는 실정이다. 글라스 울 패널과 우레탄 폼 패널이 시장에 조금씩 유통되고 있지만 여전히 EPS 패널이 시장에서 70%이상을 차지하고 있다. 그래서 EPS를 코팅, 함침, 주입 등의 여러 가지 방법도 개발되고 있으나 그 중 가장 간단하고 가격이 낮고, 샌드위치패널에 적용이 가능한 코팅법에 의한 난연제의 배합설계와 비드와 난연제의 난연 등급에 따른 최적의 배합비를 제안하고자 한다.

• Journal of Radiation Protection and Research
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• v.36 no.1
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• pp.8-16
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• 2011

We manufactured the Vac-lok that can be applied to patient of special body shape and need to special set-up position and evaluated the usefulness in the radiation therapy. The manufacture Vac-lok, It was used EVA resin and biobeadform of a diameter 1.5 mm. carried out the test of functionality, structural and analyzed the relative reproducibility of phantoms and patients. During the total period of radiation therapy, Vacuum pressure bring variety to a very small amount in the test of functionality of the manufacture Vac-lok. But It was a negligible quantity. The manufacture Vac-lok improved the relative reproducibility of phantoms than the existing Vac-lok and tolerance has a confidence less than 4% error. Also, relative reproducibility of patient increased error than phantom in the antero-posterior and lateral plan. However, the maximum set-up error was less than ${\pm}\;2.3$ mm. In conclusion, If tolerance set-up error of radiotherapy is less than ${\pm}\;3$ mm, the manufacture Vac-lok was enough possible to use and improvement of reproducibility, considering supply with the Vac-lok made to measure of special patient that produced at a low price and without delay.

• Land and Housing Review
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• v.10 no.3
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• pp.23-32
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• 2019

Vacuum Insulation Panel(VIP) has the lowest thermal conductivity among present insulations. It is composed of envelope, core material and getter. Aluminum film is usually used as the envelope of VIP, and it is important component to decide the useful life of VIP. In this research, the thermophysical properties of incombustible fiber glass core VIP were investigated with the possibility of its architectural applications. The results of this research can be summarized as follows: 1) The thermal conductivity of 20mm-thick fiber glass core VIP is resulted as 0.00177W/m·K, which means that 20mm-thick VIP can meet all the reinforced insulation guideline and it can be used in any envelope of any region in Korea. 2) As a result of the test of incombustion and gas toxicity, fiber glass core VIP was suitable for incombustible material. 3) As the test result for the long term thermal conductivity, fiber glass core VIP was found out that it would keep above 10 times insulating performance than polystyrene foam and glass fiber. 4) To meet the thermal transmittance of 0.12W/㎡K, limited-combustible insulation of expanded polystyrene foam and phenolic foam should be used respectively as thick as above 280mm and 170mm, incombustible VIP can meet the same insulation level with 20mm thickness. 5) The price competitiveness of incombustible VIP to meet the thermal transmittance of 0.12W/㎡·K was about 1,500won/㎡ higher than that of phenolic foam.