• Journal of Broadcast Engineering
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• v.14 no.4
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• pp.518-536
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• 2009

To verify the performance of a Distributed Translator Network(DTxR) system in the real world conditions, 5 legacy DTV broadcasting repeater sites were implemented with 5 DTxR systems and field-tested by the DTV field test truck. The 4 DTV broadcasting repeater sites are selected in congested areas where their service areas are overlapped and the 5th site is deviated from the other sites to examine the effect of long-delayed multipath signals. First of all, we checked the receiving signal of the main station that used as a transmitting signal in 5 DTxR systems on the pre-selected 60 test points and tested every case of a DTxR system's on & off except 1 repeater site due to the already built-in DTV repeater system. The test items are received signal electric field strength, noise margin, ease of reception and subjective evaluation of the picture quality for received signals. We used 3rd, 5th, and 6th generation DTV receivers to examine the differences of the receivability by each generation of DTV receivers. Reviewing the test results, we conclude that the DTxR system can be adopted in the current DTV Repeater sites and it could improve the quality and receivability of the main signals by extending the service areas and enhancing the signal levels in the shadow areas without using the extra broadcasting channels.

• Electronics and Telecommunications Trends
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• v.31 no.5
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• pp.80-89
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• 2016

현재 이동통신 분야에서는 5세대(5th Generation: 5G) 이동통신 표준화 작업이 한창 진행 중이며, 그 표준화 현황을 살펴보기 위하여 대표적인 국제 표준화 단체인 ITU-R에서의 활동 및 3GPP에서의 활동을 살펴보고자 한다. 최근 ITU-R WP 5D에서는 IMT-2020으로 명명되는 5세대 이동통신 비전 문서를 토대로 기술 요구사항 및 평가 기준 마련을 위한 작업이 수행되고 있으며, 3GPP의 TSG SA, RAN 및 하위 WG에서는 관련 상위 레벨 요구사항 정립 및 무선 구간에서의 기술적인 SI 논의가 수행되고 있다. 본고에서는 위 두 표준화 활동을 위주로 5G 이동통신에 대한 현황을 기술한다.

• Review of KIISC
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• v.29 no.5
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• pp.7-20
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• 2019

2019년 4월, 4세대 이동통신보다 최대 20배 빠른 속도, 10배 많은 IoT 기기의 연결, 10배 짧은 저지연 서비스를 제공하기 위해 5세대 이동통신이 세계최초로 상용화되었다. 5G 이동통신기술은 고속 대용량의 음성 및 데이터 통신을 제공할 뿐만 아니라 지연 속도와 신뢰성에 민감한 IoT 기기를 수용하기 위해 다양한 최신 기술을 적용하는 기술적 진보가 있었다. 그러나 5G 네트워크 및 서비스가 개방성, 확장성, 유연성을 제공하기 위해 분산 코어 네트워크 구조와 소프트웨어기반 아키텍처(SDN NFV, MEC, 클라우드 컴퓨팅 등)로의 기술적 변화는 새로운 공격 접근 경로와 네트워크 슬라이싱과 같은 논리적인 계층의 복잡한 보안 가시성 이슈 등 사이버보안관점에서 새로운 도전(Challenges)이 되고 있다. 본 논문에서는 5G 모바일 네트워크의 기술적 변화에 따른 보안도전과제와 해외 5G 보안 아키텍처 연구들을 분석하여 5G 보안 설계 및 운영 고려사항을 고찰하고자 한다.

• Journal of the Korean Society of Radiology
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• v.83 no.6
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• pp.1342-1353
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• 2022

Purpose We compared the radiation dose and image quality between the 2nd generation and the 3rd generation dual-source single-energy (DSSE) and dual-source dual-energy (DSDE) CT of the abdomen. Materials and Methods We included patients undergoing follow-up abdominal CT after partial or radical nephrectomy in the first 10 months of 2019 (2nd generation DS CT) and the first 10 months of 2020 (3rd generation DS CT). We divided the 320 patients into 4 groups (A, 2nd generation DSSE CT; B, 2nd generation DSDE CT; C, 3rd generation DSSE CT; and D, 3rd generation DSDE CT) (n = 80 each) matched by sex and body mass index. Radiation dose and image quality (objective and subjective qualities) were compared between the groups. Results The mean size-specific dose estimation of 3rd generation DSDE CT group was significantly lower than that of the 2nd generation DSSE CT (42.5%, p = 0.013) and 2nd generation DSDE CT (46.9%, p = 0.015) groups. Interobserver agreement was excellent for the overall image quality (intraclass correlation coefficient [ICC]: 0.8867) and image artifacts (ICC: 0.9423). Conclusion Our results showed a considerable reduction in the radiation dose while maintaining high image quality with 3rd generation DSDE CT as compared to the 2nd generation DSDE CT and 2nd generation DSSE CT.

• Information and Communications Magazine
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• v.18 no.5
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• pp.125-131
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• 2001

• Journal of the KSME
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• v.50 no.5
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• pp.52-55
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• 2010

• Journal of the KSME
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• v.50 no.5
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• pp.48-51
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• 2010

• 정보화사회
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• s.174
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• pp.4-5
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• 2005

• 전기의세계
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• v.51 no.5
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• pp.36-43
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• 2002

• Journal of Korean Electronics
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• v.24 no.2
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• pp.4-5
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• 2004