• Journal of Communications and Networks
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• v.8 no.2
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• pp.187-193
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• 2006

In this paper, we study the coexistence of orthogonal frequency division multiplexing (OFDM)-based systems beyond 3G (B3G) and point-to-point (P-P) fixed service (FS) microwave systems. The advanced general analytical model derived via a power spectral density (PSD) analysis proposed in this paper has two advantages in comparison with the conventional minimum coupling loss (MCL) method. First, the interfering signal power that appears in the band of a victim system can be easily assessed without a spectrum emission mask. Second, when transmit power is not allocated to some subcarriers overlapping the band of the victim system in order to mitigate B3G OFDM-based systems interference with other systems, the general analytical model can successfully assess the interference from the B3G systems into FS systems, whereas the MCL method incorporating the spectrum emission mask cannot be applied in the presence of the same interference condition. The proposed model can be derived in a closed form and is simply implemented with the help of simulation, and thus the solution can be obtained in significantly reduced time. Through application of the proposed model, coexistence results are analyzed in a co-channel and adjacent channel with respect to guard band and minimum separation distance.

• Korean Security Journal
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• no.38
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• pp.83-107
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• 2014

As a part of school safety network construction project, a system of school marshal in Seoul-si and a project of academy safety guard in other regions are on the way of improvement. But, the crimes in and around the school, occurring frequently, are not solved easily, as this study points out. The effective improvement way of school safety network construction project is as followings. First, to enforce assistant-class school safety teacher system in order to nurture and educate experts in school safety, as a systematic support for strengthening occupational professionalism. Second, to enforce school safety network construction projects for construct circumstances through legal fix of school safety CPTED to make students free from crimes. This study looks into the real status and problem of school safety networks, and suggests system of school safety teacher and a legal enactment of CPTED, as systematic and a planed school safety countermeasure, not temporary.

• Journal of Navigation and Port Research
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• v.26 no.4
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• pp.407-417
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• 2002

Japanese oil companies have begun to set up a mutual support system to prepare for any large scale oil spillages due to the huge increase in size of tankers since 1973. In 1990, the Petroleum Association of Japan established the Oil Spill Response Department and has been conducting researches on management of oil spill combatting materials and the effective prevention of maritime oil disasters. Japan Coast Guard, in accordance with the regulations of the OPRC in 1995, formulated the national contingency plan and built a mutual-contact network among the related government institutions. Its Guard & Rescue Department. Disaster Prevention Section has been working for the maintenance of oil spill combatting materials and coordinating related work with private organizations. The Japanese government has been strengthening the maritime oil spillage management system since the Nakhodka wreck incident in 1997.

• Proceedings of KOSOMES biannual meeting
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• 2018.06a
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• pp.122-122
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• 2018

• Proceedings of KOSOMES biannual meeting
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• 2018.06a
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• pp.72-72
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• 2018

• Proceedings of KOSOMES biannual meeting
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• 2018.06a
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• pp.119-119
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• 2018

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.249-252
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• 1998

ETSI(European Telecommunications Standards Institute) 300 34701, ITU-T(International Telecommunication Union) G.965 recommended PSTN, CONTROL, LINK CONTROL, BCC, PROTECTION protocols on V-Interfaces. But it is possible to occur misalignment between LE(Local Exchange) and AN(Access Network), especially in link identification procedure because there isn't any comment about V5.2 system management. In this paper we propose S/W guard timer to improve reliability in V5.2 link identification procedure in scope of Recommendation.

• Proceedings of KOSOMES biannual meeting
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• 2009.06a
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• pp.29-35
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• 2009

해양에서 각국의 사경비제도를 비교 분석하고 육상에서 사경비(私警備) 현황을 조사하였다. 미래의 해양치안수요의 증가에 대비하여 공경비(公警備)를 유기적으로 보조하고 수요자의 욕구에 맞춤형 서비스를 제공하는 해양에서 사경비제도 도입방안을 모색하였다. 향후 우리 나라의 해상치안환경에 부합하는 해양 사경비 경비모델을 설계해나가고자 한다.

• Proceedings of the Korea Multimedia Society Conference
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• 2001.11a
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• pp.56-59
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• 2001

OFDM 시스템은 부반송파의 직교성을 이용하는 특징으로 인하여 신호치 시간동기 및 주파수동기가 맞지 않은 경우 수신신호를 정확히 복조하기가 거의 불가능하다. 보호구간(Guard Interval)은 신호의 데이터 구간 일부분을 복사하여 심볼의 앞에 추가하는 CP(Cyolic Prefix)방식을 사용하고 있으며, 채널에서 발생하는 ISI(InterSymbol Interference)를 흡수하는 중요한 역할을 한다. 본 논문에서는 시간동기에 사용되어지는 보호구간을 여러 부구간으로 나눈 후, 이를 이용하여 심볼 타이밍 동기를 추정하고자 한다. 제안된 방법은 기존의 방법에 비해 성능의 손실없이 많은 계산량을 줄이는 방법으로서 수신기의 구조를 단순화시킬 수 있다. 여러 채널 환경에서의 모의 실험을 통해 제안한 방법과 기존의 방법을 비교하였다.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.11a
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• pp.215-215
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• 2004