• Journal of Industrial Technology
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• v.8
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• pp.71-80
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• 1988

높은 전압으로 충전된 Capacitor를 순간적으로 원통형 coil에 방전하면 순간적으로 강한 전자장 impulse가 발생한다. 이때 coil를 둘러 싼 금속 tube는 radial 방향의 힘을 얻어 팽창한다. 본 논문은 이때 tube내의 전자장분포와 tube 벽의 움직임을 integral equation method를 사용하여 해석하였다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.554-555
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• 2012

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.10a
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• pp.635-636
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• 2011

• The Transactions of the Korean Institute of Electrical Engineers
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• v.40 no.7
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• pp.690-695
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• 1991

The ability to linearize a nonlinear system by feedback and coordinate change reduces to finding an integrating factor for a one-form which is determined from the system dynamics. Utilizing Taylor series expansion of this one-form, we characterize approximate linearizabilitu. A constructive method is derived for approximate linearization up to order 2.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.10a
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• pp.372-373
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• 2013

• Journal of KSNVE
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• v.7 no.5
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• pp.737-746
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• 1997

The substructure synthesis method is used for making it easy to analyze vibration systems generally in vibration field. In the past, this method has been to be used mainly because of shortage of computer memory and CPU time. But recently this method is used for analyzing complex structure or identifying the characteristics of systems precisely. The purpose of this study is to develop acoustic substructure synthesis method that can be applied to acoustic modal analysis of complex acoustic systems. Acoustic modal analysis method to be introduced here is a method that analyze acoustic natural mode shape of the complex acoustic system by the principle of CMS(component mode synthesis method). This paper describes the acoustic modal analysis of the acoustic finite element model of simple expansion pipe by acoustic substructure synthesis method. The resutls of acoustic modal analysis analyzed by Acoustic substructure synthesis method and the results by FEM(finite element method) shows good agreement.

• Journal of the Korean Geosynthetics Society
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• v.18 no.1
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• pp.91-101
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• 2019

Recently, small-scale excavation like ground cavity restoration and buried pipe replacement works are being carried out in urban area, in order to improve living convenience. This paper describes experiment results on the ground reinforcement method that can reduce the buried pipe damage, when the differential settlement occurred due to poor compaction of ground below the buried pipe. Plate load tests were conducted to evaluate a reinforcement effect of ground using concrete mat and expansion mat in the ground below the buried pipe. The results showed that the stress reduction ratio by concrete mat and expansion mat according to the surcharge load was about 46%~48% and 39%~42%, respectively. Therefore, the differential settlement of the buried pipe and the ground deformation below the buried pipes were reduced by the reinforcement effect of the concrete mat and expansion mat. This means that it is possible to prevent a buried pipe damage due to underground cavity and ground subsidence, if concrete mat and expansion mat are reinforced in the ground below the buried pipe or on the ground between the buried pipes.

• Journal of Digital Convergence
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• v.17 no.5
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• pp.333-346
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• 2019

The purpose of this study is to find out the direction of overseas expansion strategy that should be established as a public broadcaster and a media company in order to overseas expand Korea EBS's. This study used a literature research method to analyze the related literature and data for analyzing strategies of major global media companies and overseas public service broadcasters (PSBs). As a result of the research, it suggests that the direction of EBS overseas expansion should approach both commercial business diversification and fulfillment of public responsibility. In particular, it suggests that transferring project of Korea's educational broadcasting system to developing country should be developed as a core business for spreading overseas expansion. In a follow-up study, it is necessary to carry out a research that suggests a comprehensive strategy of overseas expansion of EBS based on the result of this study.

• Journal of Korean Society of Forest Science
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• v.100 no.2
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• pp.149-153
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• 2011

This study was conducted to examine the uncertainty analysis of the stem density and biomass expansion factor for Pinus rigida in Korea. A total of 57 representative sample trees were harvested. The age class in Pinus rigida forests was divided into two, which were stands with less than 20 years and more than 21 years. The influence of stand ages on biomass expansion factor showed that it was statistically significant (p=0.0001), but it was not significant on stem density (p=0.8070). The results of this study based on the uncertainty evaluation method which were suggested by IPCC guide line indicated that stem density of the stand with less than 20 years were 30.92%, while were 25.12% the stands with more than 21years. The uncertainty in biomass expansion factor of less than 20 years and more than 21 years were 60.32% and 22.42%, respectively. The uncertainty of less than 20 years was higher compared to those stands with more than 21 years. In the case of old stand, it showed the lowest uncertainty results but younger stands showed the highest uncertainty results. This study could be applied to our country's emission factor by using stem density and biomass expansion factors which were less than 20 years and more than 21 years for Pinus rigida in Korea.

• Journal of Ocean Engineering and Technology
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• v.28 no.5
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• pp.474-483
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• 2014

The majority of existing WECs (wave energy converters) are designed to achieve maximum power at a resonance condition. In the case of a single WEC, its size must be large enough for tuning, and it has high efficiency only within a limited frequency band. Recently, wave power extraction by deploying many small buoys in a compact array has been studied under the assumption that the buoy's size and separation distance are much smaller than the water depth, wave length, and size of the array. A boundary value problem involving the macro-scale boundary condition on the mean surface covered by an infinite strip of buoys is solved using the eigenfunction expansion method. The energy extraction efficiency (${\varepsilon}=1-R^2_f-T^2_r$), where $R_f$ and $T_r$ are the reflection and transmission coefficients for a strip array of buoys, is assessed for various combinations of packing ratio, strip width, and PTO damping coefficient.