http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
LED-ID용 간섭채널환경하에서의 단극형 ZCD확산코드 적용 기법에 관한 연구
차재상,김진영,장영민,김종태,이경근,문경환 한국인터넷방송통신학회 2010 한국인터넷방송통신학회 논문지 Vol.10 No.6
최근 본 논문의 저자들은 국내에 LED 조명에 ID(Identification)를 부여하여 위치인식 기능을 수행하는 LED-ID 기술을 처음 제안하고 이에 대한 연구를 본격적으로 개시하였다. LED-ID가 적용될 수 있는 통신채널은 표면의 반사파로 인한 다중경로 간섭 성분이 존재하며 ID를 위하여 직교코드를 부여할 경우, 코드들의 상호상관에 의한 간섭성분이 존재하므로 이에 대한 해결방안이 요구되어 진다. 본 논문에서는 직교코드기반의 LED-ID 방식을 가정하였을 경우, 실내(Indoor)채널 환경에서 전송채널의 시간지연으로 인한 다중경로 간섭성분을 확산코드의 상관특성만으로 해결하여 높은 QoS(Quality of Service)를 확보할 수 있는 Unipolar ZCD(Zero Correlation Duration)확산코드 기반의 OOK(On-Off Keying)-CDMA(Code Division Multiple Access)기법을 저간섭 LED-ID기법으로 제안하고, 실내채널 환경에서의 모의실험을 통한 성능평가를 통해 제안한 시스템의 유용성을 입증하였다. Recently, This paper suggests that LED-ID technique applying positioning method for LED light. also, Authors in this paper has launched this investigation earnestly. However, there are various interferences such as MPI(Multi Path Interference) by reflected waves of the surface and interfere factors by their correlation properties of the ID in LED-ID wireless channel. Therefore, in this paper, we propose a novel OOK(On-Off Keying)-CDMA(Code Division Multiple Access) system using unipolar ZCD(Zero Correlation Duration) spreading code and verify the availability of the proposed system via the evaluation performance simulation.
DQPSK-OFDM 기반의 T-DMB 부가 정보 전송기법의 성능 분석
차재상,노정규,김건,박소라,이용태,배정남,김진영 한국인터넷방송통신학회 2010 한국인터넷방송통신학회 논문지 Vol.10 No.5
본 논문에서는 DQPSK-OFDM 기반의 T-DMB 시스템에서 워터마킹 기법을 적용하여 부가 정보를 전송하는 알고리즘에 대해 알아보았다. 제안된 워터마킹 기법을 T-DMB 시스템에 적용함으로써 지상파 방송 신호를 기반으로 위치 인식 기능뿐만 아니라 부가적인 정보를 전송하여 주파수 효율을 개선할 수 있다. 모의실험을 통하여 제안된 기법의 성능을 분석하였고 유용성을 확인하였다. In this paper, we propose the novel additional data transmission technology for DQPSK-OFDM based T-DMB system using watermarking technique. The proposed algorithms which is possible that it can transmit data in indoor or shadow region and improve transmission efficiency. We certified availability of our proposed technology by using various simulation. The results of the paper can be applied to wireless multimedia digital broadcasting systems.
반응소결법으로 제조한 Iron Aluminide-Cu 및 Ni-P 피복 SiC p 예비성형체의 특성평가
차재상,김성준,최답천 한국주조공학회 2003 한국주조공학회지 Vol.23 No.1
Effects of casting treatment of metallic Cu, Ni-P film on SiCp for SiCp/iron aluminide composites were studied. Porous hybrid performs were fabricated by reactive sintering after mixing the coated SiCp Fe and Al powder. Then the final composites were manufactured by squeeze casting after pouring AC4C Al alloy melts in performs. The change of reactive temperature, density, microstructure of the performs and microstructure of the composites were investigated. The experimental results were summa-rized as follows. The thickness of Cu and Ni-P metallic layer formed on SiCp by electroless plating method were about 0.5 ㎛ and coated uniformly. There was no remarkable change in the ignition temperature with variation of the mixing ratio of Fe and Al powder while in the case of coated SiCp it was lower about 20℃than in the non-coated SiCp the maximum reaction temperature increased with increasing Al contents, but decreased with increasing SiCp contents. Expansion ratio of perform after reactive sin-tering increased with amount of Cu coated SiCp In the case of Fe-70at.%Al, the expansion ratio was about 7% up to 8wt.% of SiCp addition but further addition of SiCp increased the ratio significantly. And in the case of Fe-50 and 60at.%Al, it was about 20% up to 16wt.% of SiCp addition and about 28% in 24wt.% of SiCp addition. The microstuctures of compounds showed that the grains become finer as amount of SiCp and mixing ratio of iron powder increased and the shape of compounds was changed gradually from irregular to spheroidal.(Received January 31, 2002)