• The Transactions of the Korean Institute of Electrical Engineers P
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• v.65 no.2
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• pp.122-129
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• 2016

Current differential protection relaying with second harmonic restraint is the main protection for large capacity power transformer. PSCAD simulation program is widely used for modeling of dynamic varying transients phenomena. This paper deals with a power transformer model and transients analysis using PSCAD software to develop IED for power transformer. Simulation was carried out using a three phase 40MVA, 154/22.9kV, 60Hz, two-winding transformer with Y-Y connection used in actual fields. The paper analyzed transformer magnetizing inrush, external fault, and internal fault conditions with this model in the time domain. In addition, we performed an analysis in the frequency domain using FFT during several conditions.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.5
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• pp.110-117
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• 2007

According to the pedestrian protection regulations of Europe and Japan, the head injury must not exceed a limitation in the defined test condition for the protection of pedestrians from a vehicle crash. However, it is difficult to evaluate the performance of protection because each regulation has different test conditions such as dummy, impact speed and so on. This circumstance needs the development of a model that describes the anthropometry of the crash victim with a sufficient accuracy. We constructed scaled pedestrian dummies using MADYSCALE. Simulations were performed for various crash speeds and pedestrian postures. The scaled Korean dummies and HybridIII dummies were used to compare the pedestrian dynamic behaviors and head injury criteria during the collision. The HIC values of scaled korean dummies were found to be higher than those of Hybrid III dummies. The impact for gait posture was less than that for standing.

• Asia pacific journal of information systems
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• v.23 no.2
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• pp.87-109
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• 2013

While many surveys show very positive attitudes on the part of consumers towards eco-friendly products, the market share actually reflecting green IT purchases remains low in most countries. The motivations behind green IT purchase behavior are still obscure. Several studies have addressed the question of green IT diffusion from economic and normative viewpoints in an attempt to interpret IT adoption behavior. This study comes at the question from a different angle, namely negative frame, examining threat and coping behaviors using the Ordered Protection Motivation (OPM) model and threat appraisal theory. The results show that attitudes toward fairness and positive change, which are precedents of threat appraisal, play an important role in determining threat appraisal. Perceived threats in the green IT arena include habit change and ecological change. Appraisal for coping with these threats directly affects initial adoption behaviors regarding available green IT, and then indirectly encourages the purchase of new green IT products.

• Geomechanics and Engineering
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• v.7 no.2
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• pp.213-231
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• 2014

An elastoplastic model for structured clays, which is formulated based on the fact that the difference in mechanical behavior of structured and reconstituted clays is caused by the change of fabric in the post-yield deformation range, is present in this paper. This model is developed from an elastoplastic model for overconsolidated reconstituted clays, by considering that the variation in the yield surface of structured clays is similar to that of overconsolidated reconstituted clays. However, in order to describe the mechanical behavior of structured clays with precision, the model takes the bonding and parabolic strength envelope into consideration. Compared with the Cam-clay model, only two new parameters are required in the model for structured clays, which can be determined from isotropic compression and triaxial shear tests at different confining pressures. The comparison of model predictions and results of drained and undrained triaxial shear tests on four different marine clays shows that the model can capture reasonable well the strength and deformation characteristics of structured clays, including negative and positive dilatancy, strain-hardening and softening during shearing.

• 방재와보험
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• s.17
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• pp.42-45
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• 1982

• 방재와보험
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• s.19
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• pp.43-47
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• 1983

• 방재와보험
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• s.47
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• pp.73-75
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• 1990

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 1998.11a
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• pp.17-19
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• 1998

• Journal of the Korea Institute of Information Security & Cryptology
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• v.8 no.3
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• pp.3-15
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• 1998

본 논문에서는 다중보호대책으로 구성된 정보보호시스템의 보호효과를 평가하기 위한 새로운 모델을 제안한다. 제안한 모델은 정보보호시스템이 요구되는 보호수준에 부합하는지 결정할 수 있게 하며, 또한 구축된 정보보호시스템의 위혐분석을 위하여 활용될 수 있다.

• Journal of Radiation Protection and Research
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• v.41 no.4
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• pp.409-417
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• 2016

Background: Airborne radioactive particulate in many important nuclear facilities (particularly nuclear power plants) will have a strong impact on the relative public dose if they are released into the corresponding environment traversing the stack or vents. The radiation protection researchers have regarded the relative environment assessing and estimation of public doses. And the model of assessing impact of discharges radioactive substance to the environment have been recommended by many international organizations (e.g. IAEA) with the nuclear energy safety and radiation protection. Materials and Methods: This paper introduced the generic models that were suggested by International Atomic Energy Agency (IAEA), for use in assessing the impact of discharges of radioactive substances to the environment (e.g. IAEA Safety Report Series No.19). Results and Discussion: The writers of this paper, based on the recommend methods, assessed the discharge limits in some airborne radioactive substances discharging standards. The reasons that IAEA method are introduced are mainly the following considerations: IAEA is one of international organizations with some authorities in the nuclear energy safety and radiation protection; and, more important, the recommend modes are operational methods rather than the methods having little operations such as that have used by some researchers. Conclusion: It is wish that the introduced methods in this paper can be referenced in draft or revise of the standards related to discharges of radioactive substances to the environment.