• Satellite Communications and Space Industry
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• v.8 no.2 s.19
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• pp.156-162
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• 2000

• Satellite Communications and Space Industry
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• v.8 no.3 s.20
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• pp.66-73
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• 2000

• 정보통신주요정책설명회
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• s.2005
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• pp.99-127
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• 2005

• Satellite Communications and Space Industry
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• v.15 no.1
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• pp.48-59
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• 2008

• Satellite Communications and Space Industry
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• v.15 no.1
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• pp.41-47
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• 2008

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.6
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• pp.35-39
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• 2018

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.8
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• pp.828-837
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• 2014

With the rapid development of radio technologies, there have been actively researching the convergence between radio technology and other industry as well as wireless communications itself. In this paper, we investigate the paradigm shift of radio policy as radio technologies such as small cells and cognitive radio advance, and analyze the directions of spectrum policy and radio technology to promote the creative use of radio waves. In particular, we propose the spectrum policy for the expansion of open spectrum policy, technology development of interference management, and restructuring of the Korean radio law.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.1
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• pp.43-50
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• 2003

전자산업과 전파통신기술이 고도로 발전함에 따른 전파 이용의 증대로 인해 전자파환경 EMI/EMS이 사회적 문제를 야기하고 있다. 이에 따라, CISPR(Comite Internationale Special des Perturbations Radioelectrique), FCC (Federal Communications Commissions) ANSI (American National Standards Institute)등의 기구는 EMI/EMC 대책을 위해 전파환경의 규정을 제정하고 있다. 또한 EMI/EMC 측정을 위한 전파무향실(anechoic chamber)용 전파흡수체는 20 dB 이상의 전파흡수능이 요구된다. 종래의 EMI 측정 주파수 범위는 30 MHz～l,000 MHz 이었으나 1998년 11월, CISPR11은 1 GHz~18 GHz를 추가하는 안을 받아들였다. 본고는 새로운 형태의 다층형 페라이트 전파흡수체를 제안하고 등가재료정수법을 사용하여 광대역 설계를 시도한 것이다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.5A
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• pp.917-925
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• 2006

Experimental tests were performed to estimate velocities of the acoustic signals through prestressed concrete beam and source locations using acoustic emission (AE) techniques. Seven AE sensors are mounted on the surface of 5m length test beam with equal spacing and using Schmidt Hammer AE events are made at 18 locations. The velocities of AE signals are estimated using the time differences of arrival times and the distances between the source locations and the AE sensor locations. In addition, using the Least Square Method, the AE source locations are re-evaluated reversely using both of the arrival times and the velocities of AE signals. Test results show the average velocity of the AE signals is about 4,000 m/sec and the velocity decreased with the increase of the distance from source locations to AE sensors due to the effect of attenuation. Based on the estimation of the source locations, it is observed that the errors of source locations are decreased when the velocities of each AE sensor are used rather than the average velocity.

• The Safety technology
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• no.203
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• pp.6-6
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• 2014