• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.05a
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• pp.292-297
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• 2005

This paper proposes a simple MPPT control scheme of a Current-Control-Loop Error system Based that can be obtains a lot of advantage to compare with another digital control method, P&O and IncCond algorithm, that is applied mostly a PV system. An existent method is needed an expensive processor such as DSP that calculated to change the measure power of a using current and voltage sensor at the once. Therefore, it is applied a small home power generation system that required many expenses. But, a proposed method is easy to solve the cost reduction and power unbalance problems that it is used by control scheme to limit error of a current control of common sensor. This proposed algorithm had verified through a simulation and an experiment on battery charger using PIC that is the microprocessor of a low price.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2007.11a
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• pp.488-492
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• 2007

In this study, we investigated how to distinguish customer delivered value to re-purchasing in fierce B2C industry. To identify key managerial variables that could distinctively impact re-purchasing, we first identified customer value proposition as per the customer buying decision process. Next, core value propositions of choice efficiency and competitive price are defined to determine vendor satisfaction during the searching stage and purchasing stage. The trust level is also introduced in the sense of reflecting confirmation to guarantee after purchase security. Then, significant managerial variables to impact on core value propositions are extracted. The resulting structural model illustrated that search convenience and quality assurance affect the choice efficiency, and re-purchase intention is strongly explained by both the vendor satisfaction and trust level. The empirical testing results also support that transaction cost reduction is key determinant of shopping at the Internet shopping mall. Furthermore, trust level should be combined to induce re-purchasing in addition to transaction cost savings.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.11
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• pp.1907-1912
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• 2016

In fact, in order to obtain good performances and low torque ripple, a high-resolution sensor is needed, which is costly and usually needs a special construction for the machine. So researchers are becoming aware of their cost and are exploring the possibility of cost reduction. Information of rotor position is necessary to drive Linear Switched Reluctance Motor(LSRM). Therefore, linear optical encoder is used to detect a mover position. Normally, since the price of encoder, which is used for linear motor is relatively higher than the one used for rotory motor and the cost of additional equipment increases with the length of motor. This is not always appropriate, considering economical efficiency in case of using the linear optical encoder. As a results, LSRM has a great part for the total cost. Therefore, in this paper, we propose LSRM position detecting modeling with reflective type photo-sensor. Additionally, we have investigated the possibility of the reduced position sensor for LSRM drives with advanced control technique. To certify the overall characteristics of the proposed method, a simulation using PSIM software has been carried out and the informative results are displayed.

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.2
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• pp.230-237
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• 2012

Engine makers are lately interested in the gas engine development as the alternative for diesel engine in order to cope the rise of oil price and the environmental regulation. So, STX has developed the 1.6MW gas engine which was converted from 22HLX diesel engine. The gas engine developed with precombustion chamber, which has good performance of 21bar BMEP at engine speed 1000rpm and low $NO_X$ emission of 50ppm at 15% oxygen composition, has been developed recently. Especially, it has a good thermal efficiency of 45% and a reduction efficiency of green house gas($CO_2$) emission of 25% than a conventional diesel engine.

• Korean System Dynamics Review
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• v.7 no.2
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• pp.57-80
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• 2006

Nuclear technology made a great contribution to the national economy and society by localization of nuclear power plant design, and by stabilization of electricity price, etc. It is very important to conduct the retrospective analysis for the nuclear technology contribution to the national economy and society, but it is more important to conduct prospective analysis for the nuclear technology contribution. The term "technology value" is often used in the prospective analysis to value the result of technology development. There are various definitions of technology value, but generally it means the increment of future revenue or the reduction of future cost by technology development. These technology valuation methods are widely used in various fields (information technology or energy technology, etc). The main objective of this research is to develop valuation methodology that represents unique characteristics of nuclear power technology. The valuation methodology that incorporates market share changes of generation technologies was developed. The technology valuation model which consists of five modules (electricity demand forecast module, technology development module, market share module, electricity generation module, total cost module) to incorporate market share changes of generation technologies was developed. The nuclear power technology value assessed by this technology valuation model was 3 times more than the value assessed by the conventional method. So it was confirmed that it is very important to incorporates market share changes of generation technologies. The valuation results of nuclear power technology in this study can be used as policy data for ensuring the benefits of nuclear power R&D (Research and Development) investment.

• Environmental and Resource Economics Review
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• v.9 no.5
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• pp.853-876
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• 2000

The purpose of this paper is to come up with the measures for sustainable development of the agricultural sector in store for the strengthened U.N. Framework Convention on Climate Change. We analyze the spillover effects of Methane and Nitrous Oxides taxes (carbon tax) on the Korean agricultural sector. Unlike the other sectors, the agricultural sector has a unique characteristic generating greenhouse gas in the process of production itself even without consuming much fossil fuel. In order to estimate the impacts of those taxes, non-linear optimization method has been used with various assumed scenarios. The production effect, income and' price effect, and greenhouse gas emission reduction effect in the agricultural sector have been estimated through this method. The empirical results show that the paddy sector has a bigger tax effect than the livestock sector. In the paddy sector, the carbon tax has more impacts in the suburban areas than in the rural areas, while the swine farming section in the livestock sector has a conspicuous income effect in the midst of low greenhouse gas emission effect. These results allude us to apply graded tax rates to the crop, the livestock, and the region of different kind. Even if the agricultural sector has a less tax effect when compared with other industrial sectors, an environmental tax might be an effective measure to prevent global warming.

• Journal of the Korea Institute of Military Science and Technology
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• v.2 no.1
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• pp.159-169
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• 1999

Recently a firewall is being employed to protect hacking by controlling the traffics. The security services in the firewall include authentication, access control, confidentiality, integrity, and audit trail. A token is adapted for authentication to the firewall. A token has a small battery within which has restricted power capacity, This paper proposes a novel cost-effective firewall token for hacking protecting on transmission control protocol/internet protocol (TCP/IP) based network. This paper proposes a fast exponentiation method with a sparse prime that take a major operation for a public-key crypto-system and a major power consumption in the token. The proposed method uses much less amount of modular operations in exponentiation that is reduced of battery's capacity or CPU's price in the token.

• Asian Journal of Atmospheric Environment
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• v.8 no.1
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• pp.59-68
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• 2014

The Fukushima nuclear accident in 2011 had an extensive impact on the national electricity plans. This paper outlines alternative electricity scenarios that meet the goals of nuclear phase-out and greenhouse gas (GHG) emission reduction. This paper also analyzes the results of each scenario in respect to the electricity mix, GHG emissions, costs and employment effects. The Long-range Energy Alternatives Planning system (LEAP) model was used to simulate the annual electricity demand and supply system from 2011 to 2030. The reference year was 2009. Scenarios are reference (where existing plans are continued), A1, A2, B1, B2, and C2 (where the levels of demand management and nuclear phase-out are different). The share of renewable energy in the electricity mix in 2030 for each scenario will be increased from about 1% in 2009 to 8% in the reference scenario and from 11% to 31% in five alternative scenarios. Total cumulative cost increases up to 14% more than the reference scenario by replacing nuclear power plants with renewable energy in alternative scenarios could be affordable. Deploying enough renewable energy to meet such targets requires a roadmap for electricity price realization, expansion of research, development and deployment for renewable energy technologies, establishment of an organization dedicated to renewable energy, and ambitious targets for renewable energy.

• 한국태양에너지학회:학술대회논문집
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• 2008.04a
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• pp.178-183
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• 2008

Recently, sick house syndrome caused by pollutants and contamination of buildings crops out in residential environment of buildings. According to price increase of global oil, comfort of occupants in indoor air quality is required with reduction of energy consumption and environmental load. So, building performance certification criteria come into effect for improvement of building energy efficiency and performance in environment at home and abroad. GBCC(Green Building Certification Criteria) of domestic country as a Criteria is managed Korea Green Building Council(KGBC) for green building. Thus, purpose of this study is to design a direction of Green Building Certification Criteria for improvement through analysis of GBCC application elements and selected building.

• 한국태양에너지학회:학술대회논문집
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• 2008.04a
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• pp.318-323
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• 2008

First aim of this study is to investigate consumer's actual value for environment related performance of house by using three different method, Ranking, Analytical Hierarchy Process (AHP) and Conjoint Analysis method. Second aim is to estimate consumers' monetary value about environment related factor through Marginal Willing to Pay(MWTP), and third aim is to find out the difference of values between the groups classified according to respondents' characteristics. A questionnaire survey was carried out in Seoul in order to clarify the preference and monetary value of four selected attributes. They are environmental performance, residents' health, home automation and increase of floor area. As a result, people showed high values in the order of health, environmental consideration, increase of floor area and home automation. Moreover, it was found out that MWTP for environmental performance and health are higher than market price. In addition, the group of high age and group of female showed high values for the reduction of $CO_2$ emission