• Journal of Microbiology and Biotechnology
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• 제22권7호
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• pp.967-974
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• 2012

Cultivation of Spirulina platensis using ammonium salts or wastewater containing ammonium as alternative nitrogen sources is considered as a commercial way to reduce the production cost. In this research, by analyzing the relationship between biomass production and ammonium-N consumption in the fed-batch culture of Spirulina platensis using ammonium bicarbonate as a nitrogen nutrient source, an online adaptive control strategy based on optical density (OD) measurements for controlling ammonium feeding was presented. The ammonium concentration was successfully controlled between the cell growth inhibitory and limiting concentrations using this OD-based feedback feeding method. As a result, the maximum biomass concentration (2.98 g/l), productivity (0.237 g/l d), nitrogen-to-cell conversion factor (7.32 gX/gN), and contents of protein (64.1%) and chlorophyll (13.4mg/g) obtained by using the OD-based feedback feeding method were higher than those using the constant and variable feeding methods. The OD-based feedback feeding method could be recognized as an applicable way to control ammonium feeding and a benefit for Spirulina platensis cultivations.

• 한국해양환경ㆍ에너지학회지
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• 제8권4호
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• pp.193-202
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• 2005

본 논문에서는 침몰선박이 보유하고 있는 모든 위해요인을 체계적으로 규명하고, 위해요인으로 인한 손실정도를 정량적으로 산출하여 효과적이고 일관된 침몰선박 관리와 과학적이고 경제적인 침몰선박 처리 의사결정에 활용할 수 있는 침몰선박 위해도 평가모델 및 정보시스템의 개발내용을 소개하고자 한다.

• Journal of Biosystems Engineering
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• 제25권3호
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• pp.203-212
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• 2000

One of the obstructing factors against managing large-scaled dairy farm in Korea has been heavy labor requirement for feeding dairy cows. A tractor attached TMR mixer was developed to reduce the cost and to provide economic benefit in this research. The TMR mixer was designed to have a feeding capacity of 35 heads at a batch with various functioning systems of paddle type mixer, cutter and grinder, delivery conveyor, weighing console, power transmission train, and mounting trailer. The maximum power required during the mixing operarion was 26.3 kw(P.T.O), readily available from 32kw-rated tractors, which had been widely used in Korea. Low coefficient of variation(14.0%) revealed an uniform mixing performance of the mixer. The mixer can also be used in compost mixing as well as concentrates and roughage.

• 전기학회논문지
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• 제66권6호
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• pp.892-897
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• 2017

Until now, it has been for choosing most economic result to be generally used for designing remote MicroGrid (MG) system. It is able to make economic benefit by reducing operation cost, but proportion of renewable energy will be minimum. In other words, it is difficult to get an effect by renewable energy because economic feasibility is an only consideration. Therefore, various factors should be considered and design objectives should be are diversified to design proper remote MG system. In this paper, remote MG system is classified into two types according to design objectives, and they are analysed through case study based on economic evaluation. In addition, economic feasibility for each type is analysed through sensitivity analysis according to various factors that affect the design results of the system.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2006년도 춘계종합학술대회
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• pp.924-926
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• 2006

저전력 집적회로 기술과 MEMS (micro electro-mechanical systems) 기술이 융합된 산물인 스마트 센서는 작은 크기, 저비용, 저전력의 특성을 가지고, 그와 더불어 임베디드 어플리케이션에 사용되기에 적합하므로 이동 환경 컴퓨팅 분야에서 주목을 받고 있다. 이 센서들이 이동 통신에 적용되면 어플리케이션의 특성에 따라 인간의 접촉이 쉽지 않은 곳과 원격 통신이 가능하다는 장점이 있다. 이러한 혁명적인 원격 네트워크 기술로 인하여 활동적인 연구자들에게 엄청난 연구의 장이 열린 것이다. 본 논문에서는 그 중 한가지의 어플리케이션인 열센서 카메라에 대한 응용 분야로, 적외선 열센서 카메라에 대한 미세 조정을 위한 시스템 구축 방안에 대하여 논의한다.

• 한국항해항만학회지
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• 제41권5호
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• pp.287-296
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• 2017

The Formal Safety Assessment (FSA) is a structured and systematic methodology developed by the IMO, aimed at assessing the risk of vessels and recommending the method to control intolerable risks, thereby enhancing maritime safety, including protection of life, health, the marine environment and property, by using risk analysis and cost-benefit assessment. While the FSA has mostly been applied to merchant vessels, it has rarely been applied to a DP vessel, which is one of the special purpose vessels in the offshore industry. Furthermore, most of the FSA has been conducted so far by using the Fault Tree Analysis tool, even though there are many other risk analysis tools. This study carried out the FSA for safe operation of DP vessels by using the Bayesian network, under which conditional probability was examined. This study determined the frequency and severity of DP LOP incidents reported to the IMCA from 2001 to 2010, and obtained the Risk Index by applying the Bayesian network. Then, the Risk Control Options (RCOs) were identified through an expert brainstorming and DP vessel simulations. This study recommends duplication of PRS, regardless of the DP class and PRS type and DP system specific training. Finally, this study verified that the Bayesian network and DP simulator can also serve as an effective tool for FSA implementation.

• 한국IT서비스학회지
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• 제11권1호
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• pp.173-196
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• 2012

Cloud computing is provided on demand service via the internet, allowing users to pay for the service they actually use. Since cloud computing is emerging stage in industry, many companies and government consider adopting the cloud computing. Actually a variety of factors may influence on the adopting decision making of cloud computing. The objective of this study is to explore the significant factors affecting the adoption decision of enterprise cloud computing. A research model has been suggested based on TOE framework and outsourcing decision framework. Based on 302 data collected from managers in various industries, the major findings are following. First, the benefit factors of cloud computing service such as agility and cost reduction have direct and positive effects on adoption of the service. Second, lock-in as a risk factor of cloud computing service has a negative effect while security has not. Third, both internal and external environment factors have positive effects on adoption of the service.

• 정보처리학회논문지C
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• 제10C권4호
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• pp.405-412
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• 2003

As the XML is approved standard language by the UN, the progress which complemented the XML security has being processed rapidly. In this paper, we design and implement the "XML-Signcryption" as a security mechanism to protect the XML document that can operate between other platforms. The signature and encryption which is the standard specification in W3C needs to be able to proceed them separately. Generally the signature and encryption require four times modular exponential operation, however the signcryption only needed three times modular exponential operation. This will benefit overall system effectiveness in terms of cost. And this scheme offers to convenient the user, because the signature and encryption implement as a single XML format. This tool can save the parsing time as a number of tags is few within a document. And also, in this paper, based on a research of Web Services security, we can apply XML-Signcryption to the SOAP message to provide the security services. Based on the XML-Signcryption scheme which provides confidentiality, integrity, authentication and non-repudiation to the XML document and Web Service security simultaneously.

• 상하수도학회지
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• 제31권3호
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• pp.205-217
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• 2017

This paper tries to show the efficiency of water financing between central and local governments. From the year of 2017, the operation and maintenance costs for change water pipes has been provided by central government as block grants system(RDSA: Regional Development Special Account). Even though the water financing is responsible for local government, water drought and high production cost in poor area affects the quality of life nowadays. Then, fiscal transfer through block grant for water financing has been decided to invest regional SOC. The purpose of the paper sheds light on the function of the block grant for public provision by water financing. The firstly tried empirical results are based on the survey from local governments and ministry of environments. The point of the empirical analysis shows that the local governments does not have proper measurement for unexpected water leakage and termination until now. In a policy manner, the paper raises the issues about benefit principle for water users by the increase of tariffs. In order to do so, the paper investigates the relationship between the water provision and fiscal status of each local governments.

• Journal of the Korean Wood Science and Technology
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• 제33권1호통권129호
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• pp.97-110
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• 2005

본 연구는 최근 미국 에너지 시장에서 바이에너지가 차지하는 위치와 공급상황에 대하여 조사 연구되었다. 특히 제 1보에서는 미국에서 실용화되고 있는 목질 바이오매스를 이용한 바이오매스 전기제조기술(직접 연소 발전, 산업체의 폐열발전, 가스터빈과 스팀터빈 연합 발전 및 모듈화된 발전시스템등), 전기생산 시설 및 공급가의 경제성등에 대하여 검토하였고, 제 2보에서는 바이오매스 전기에 대한 미국의 정책 및 마케팅전략, 그리고 바이오매스 전기 사용이 가져오는 환경적 경제적 이익 및 발전 장벽(Benefit and Barriers)등에 대하여 조사 연구되었다.