• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.3
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• pp.610-616
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• 1990

The fracture mechanics analysis of surface cracks in plates and cylindrical geometries is important in the integrity evaluation of flawed structural components. The objective of this paper is, thus, to numerically investigate an interaction effect of two surface cracks in plate and cylindrical geometries. The effect of crack spacing on the magnitude of the stress intensity factor(K) is investigated using the line-spring model. For the case of a finite plate under uniaxial loading, the effect of crack spacing on the K values is negligible. However, for the case of a cylinder under moderate internal pressure, a significant increase in K values is observed at the deepest point of the surface crack.

• Journal of the Korean Society for Railway
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• v.15 no.5
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• pp.454-458
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• 2012

The CBTC(Communication based Train Control) and WPAN(Wireless Personal Area Network) systems employed on 2.4GHz ISM band wireless networks provide complementary service within the same environment. Coexistence between the networks will be impaired if the mutual packets are uncertainty associated the timing or gaussian distance. This paper analyzes the impact of the mutual interference and proposed method to minimize the effect of the WPAN system signals on CBTC system. The performance analysis is illustrated by examining the symbol error rate versus signal to noise interference ratio in terms of carrier frequency offset. The method contributes to reduce the symbol error rate drastically. However it can't be a fundamental solution for the impact on the interference problem. It may be needed for railway only frequency after checking the problems of the current railway frequency.

• Journal of Ocean Engineering and Technology
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• v.6 no.1
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• pp.29-42
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• 1992

자유표면하에 잠긴 복잡한 3차원 물체 주위의 흐름을 해소하기 위한 수치계산법이 TUMMAC(Tokyo Univ. Modified Marker And Cell)법을 기초로 하여 개발되었다. 임의물체의 no-slip 3차원 물체표면조건을 보다 간단히 처리하기 위하여 "porosity"라는 개념이 도입되었으며, 담수성에 잠겨 있는 해저돌출물 주위의 유동을 계산하여 그 응용성을 검토하였다. 돌출물 후방의 복잡한 와동들의 상호간섭이 잘 시뮬레이션 되었다.시뮬레이션 되었다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.13 no.1
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• pp.85-93
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• 1988

Installation of the digital carrier system is increased rapidly in the telecommunication network, and most of systems are operating over a twisted pair conductor. Many systems are accommodated in multipair cable for their economical installation, therefore we must consider tha crosstalk interference between digital systesm. This paper considers the calculation method which determine crosstali interference between signals in multipair. And the transmission margin at a certain error rate is analyzed considering crosstalk power. Finally, this paper estimates the crosstalk noise susceptibility of 2.048Mbps relative to 1.544Mbps PCM system and 1.544Mbps relative to 2.048Mbps PCM system, and then considers the methos which both systems can operate together in a same cable.

• Proceedings of the Korea Information Processing Society Conference
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• 2015.10a
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• pp.150-153
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• 2015

사물인터넷(IoT; Internet of things)은 사람의 간섭 없이도 모든 사물들이 인터넷으로 연결되어 상호 통신하고 대화하여 주변 환경을 분석해 서비스를 제공한다. 그러나 IoT 장치 간의 플랫폼이나 서비스 요구사항 등이 표준화 되어 있지 않아, 다른 제조사 또는 서비스 영역에서는 상호연동이 불가능하다는 문제점을 가지고 있다. 이러한 문제를 해결하기 위해 다양한 IoT 플랫폼들이 개발되었지만 이들 플랫폼 간의 상호운용성 문제가 이슈화되고 있다. 따라서, 본 연구에서는 다양한 IoT 플랫폼들 간의 상호운용성 보장을 위하여 기존 IoT 플랫폼들을 분석하고, 메타데이터 레지스트리(MDR; Metadata Registry) 기반의 새로운 IoT 플랫폼 참조모델을 제안한다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.04a
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• pp.197-202
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• 2004

It is well known that the hydrodynamic interaction forces between ship and bank wall affect ship manoeuvring motion. This paper deals with the interaction effect acting on a ship navigating closely in the proximity of bank wail. In this paper, the calculation method based on the slender body theory for estimation of the hydrodynamic interaction forces between ship and bank wail is applied. The hydrodynamic interaction forces acting on a ship during passing through the proximity of the bank wail are predicted to evaluate an influence of these interaction forces on ship manoeuvrability. The calculation method used in this paper will be useful for prediction of ship manoeuvrability at the initial stage of design, for automatic control system of ship in confined waterways, for discussion of marine traffic control system and for construction of harbour.

• Korean Journal of Optics and Photonics
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• v.1 no.2
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• pp.191-197
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• 1990

An experiment on the phase stability of injection-locked beam is done by using AlGaAs semiconductor lasers. The coherence of two beams from the master and slave lasers is measured by interference between the beams in the Twymann-Green interferometer. The phase change of the output beam of the slave laser as a function of the driving current is measured in the Mach-Zehnder interferometer consisted of the master and slave lasers and a value of 2.5radlmA is obtainccl.

• Journal of Digital Convergence
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• v.12 no.4
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• pp.213-226
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• 2014

Previous research on work and life balance mainly focused on workers' passive acceptance of interferences rather than active management of them. However, workers can also actively manage boundaries to enhance work and life balance. To find ways to enhance work and life balance, especially in the context of Smart Work, factors having effects on the work/nonwork interferences and their relationships should be firstly investigated. The results show that in a work domain, both boundary strength at work and job autonomy negatively influence on the nonwork to work interferences; in a nonwork domain, both boundary strength at nonwork and autonomy have negative effects on the work to nonwork interferences.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.4
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• pp.873-882
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• 1990

본 연구에서는 작은 크랙이 중앙 크랙선단 주위에 대칭으로 배치 분포되어 있 는 유한 평판의 경우에 대한 것으로, 우선 균일분포하중을 받는 정방형판에 분포크랙 이 있는 경우 분포크랙의 위치에 따른 중앙 크랙 선단에서의 응력확대계수의 변화를 유한요소법으로 해석하여 등응력확대계수 곡선들로 나타냈다. 그리고 크랙들 사이의 상호 간섭에 의해 일어나는 소성영역도 고려하여 그 안정성을 검토하여 보았는데, 특 히 크랙들이 서로 가까와 지면 그 크랙들 간에 상호간섭이 커져 소성영격이 크랙선단 주위에 크게 발생되므로써 크랙들은 쉽게 연결되고 합체로 인한 크랙성장이 되어 파괴 됨을 예측할 수 있고 중앙 크랙선단 주위의 분포크랙의 위치에 따른 소성영역 변화도 유한요소법으로 해석하여 도식적으로 나타냈다.

• Journal of Broadcast Engineering
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• v.18 no.3
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• pp.445-454
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• 2013

By using the radio propagation prediction of Rec. ITU-R P.1546, geographic information system, and S-I plane, we presented the methodology of interference analysis based on the minimum coupling loss, and also suggested the local coordinate system for calculating azimuth and elevation angles between the victim receiver and the interferer for an arbitrary antenna pattern. To check the presented algorithm, the map with the land-sea mixed area was taken for the given area of $80{\times}60[km^2]$ as real geography information. Field strength, path profile, and protection ratio with maximum allowable interference level have been illustrated for radar and fixed wireless system for the assumed frequency. In addition interference power of the victim receiver was calculated asa function of azimuth and elevation angles of the interferer. The developed methodology of interference analysis in the VHF and UHF bands can be actually applied to assess interoperability as well as compatibility in the civil or military applications.