• Journal of Technology Innovation
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• v.16 no.1
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• pp.191-213
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• 2008

This study investigates the effect of technology import and R&D investment on the value of the firm in Korea. The result shows that the technology import announcement effect of firms with a low R&D investment is higher than that of firms with a high R&D investment. The evidence suggests that technology import can substitute the existing R&D capability of the firm. In addition, the result shows that there is an optimal level of technology import and R&D investment to maximize the value of the firm. In particular, firms with a low R&D investment and a large amount of technology import experience the highest announcement effect. The study concludes that an adequate allocation of fim's capital between R&D investment and technology import is needed for firm's optimal technology strategy.

• Agricultural and Biosystems Engineering
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• v.1 no.1
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• pp.16-21
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• 2000

Measurement of spray deposit is necessary for evaluation of a chemical application technology. However it is not easy and time consuming. A simple method for measuring the deposition amount of spray using a tracer and a spectrophotometer was developed. Various materials were tested to determine an adequate tracer. Food dye was selected as a tracer, because it was cheep and easily treatable. Using NIRS(Near Infrared Reflection Spectrophotometer), a regression curves between maximum absorbance of a solution and concentration of the tracer were obtained. Yellow food dye solution showed a peak of spectrum at 452 nm, and absorbance of peak showed a tendency to increase as concentration increased. Green or pink food dye were tested and judged to be good tracers. However, tracer concentration should not exceed certain limits in order to measure maximum absorption. Using spraying liquid with known tracer concentration and known amount of washing liquid, spray deposit amount on real targets on leaves could be estimated at less than 13% error level.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.694-695
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• 2011

The recent concerns over the threat of global climate change and the requirements of national reduction of $CO_2$ emission have led to the diversification of energy resources and a large scale integration of renewable resources. In these circumstances, the policy decision currently made by the government sector includes several programs to promote the equipment of large scale generating assets to use wind energy. However, the power systems and wind farms need such innovative operation scheme schemes that maintain an adequate level of system security for continuing growth of renewable resources. This paper presents a method for determining optimal operating points for wind farms by making use of a nonlinear interior point method.

• Journal of the Korean Institute of Educational Facilities
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• v.19 no.6
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• pp.37-44
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• 2012

According to the reports by the OECD and UN in 2012, Korea is evaluated highly of its enthusiasm and level of education compared to other evaluation indices. This result implies that Korea has much more interest in education than other countries. In reality however, the nation does not provide an adequate condition in other aspects such as the quality of life of citizens and its educational environment. For this reason, our country currently promotes and operates various policies and environmental improvements in an effort to coincide with the timely demands and to cope up with the advanced educational system. Researches in particular are being implemented on Korea's current educational policies by specialists related to their specific fields. This study is to understand the periodic trends of the educational facilities according to the specialist-oriented articles and apply it as a basic resource to the future researches on the corresponding field.

• Journal of Electrical Engineering and Technology
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• v.11 no.1
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• pp.76-85
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• 2016

This paper presents a method of decision on where bus splitting is needed to reduce fault current level of power systems and to satisfy the fault current constraints. The method employs a modified fault current constrained optimal power flow (FCC-OPF) with X variables for the candidate locations of splitting and for decision making on whether to split or not, it adopts soft-discretization by augmenting inversed U-shaped penalty terms. Also, this paper discusses the procedure on the adequate selection of bus splitting locations based on the results of the modified FCC-OPF, to reduce the total number of the actions taken.

• Proceedings of the Korean Institute of Interior Design Conference
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• 2006.11a
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• pp.170-173
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• 2006

Escalating rate of working women is increasing the necessity for day-care centers. Moreover, insufficient child-care system is known as one of many factors that relate to the seriously low birth-rate of our society. Therefore providing more adequate day-care centers can not be regarded as a mere personal necessity but a social need to be considered at corporate and governmental level. The current study analyzes 'Reggio-emilia teaching method' which is a type of early childhood educational program and its relationship to the built environment. It also examines current interior spaces of Reggio-emilia day-care centers and suggests designs for an day-care center appropriate for educating children in Korea.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1760-1765
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• 2007

This paper shows a derating design approach for LED reliability improvement. The LED is widely used in display devices or circuits. The main failure of interest is defined as 100% reduction of the light output intensity of LED resulting from corrosion due to stresses, i.e. temperature and humidity. The lifetime is varied according to the stress levels under where the LED operates so that correlation of the lifetime to these stress levels over time is modeled through accelerated life testings. A derating design approach to accomplish a required reliability level of LED is proposed to determine adequate the stress levels. In the approach, $B_{10}$ life, Failure rate, Sensitivity Analysis of LED are used as a reliability metric.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.3
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• pp.444-449
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• 2009

This paper introduces a method to establish performance criteria of the in-house power supply system in nuclear power plants. The performance criteria of the system is presented in terms of the number of function failures and amount of the out-of-service time that can be allowed commensurate with the probabilistic safety assessment results of the nuclear power plants. To obtain the performance criteria such as reliability and availability, the functions of the system were analyzed and probabilistic assessment results were utilized. This method provides quantitative guidelines in selecting and monitoring system functions to determine an adequate level of maintenance quality in order to ensure the probabilistic goals for the safety of the nuclear power plants.

• Proceedings of the KIEE Conference
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• 2007.10c
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• pp.214-216
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• 2007

With the arrival of ubiquitous networking environment, it has been needed to build up the u-infrastructure for railway, and so the realization of ubiquitous rail system could be preferred. We have studied the direction for development of technology for realizing u-rail system through the analysis of the condition and demand on railway system, and investigated the requirements, level of technology and applicability of information infrastructure for realizing u-Rail. And also analyzed the technology based on railway information to determine the role of existing information system and connect it, which is adequate for u-Rail and the project selection.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.12
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• pp.54-59
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• 2011

LED lightings typically do not fail catastrophically during use. However, over time the light output will gradually depreciate. Even if there are same LED lighting, they are so different at all. because of dissimilar the use and environment of each LED lighting. In this paper, we make a description of reliability analysis procedures for the degradation data using collected field data. Reliability analysis procedures are consisted of estimating degradation models and failure time, verification of distribution and parameters of the distribution, and reliability measures estimation. At some point in time, the light emitted from an LED lightings depreciates to a level where it is no longer considered adequate for a specific application.