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주파수 도약 통신위성 중계기의 다상 DFT 필터뱅크 과도기 응답 분석
이대일(Daeil Lee),주재관(Jaikwan Joo) 한국항공우주학회 2014 韓國航空宇宙學會誌 Vol.42 No.7
통신위성 중계기에서 효과적인 다중채널 처리를 위하여 여러 가지 필터뱅크들이 사용되어져 왔다. 특히 구현의 간단함으로 인하여 대역폭이 일정한 복수의 다중채널을 다루는 경우 다상 DFT 필터뱅크가 광법위하게 사용되어져 왔다. 하지만 주파수도약 통신위성 중계기에서 Polyphase DFT 필터뱅크를 사용하여 다중채널 처리를 할 경우 주파수 도약 홉과 홉 사이에서 발생하는 비정상적인 과도기 응답으로 인하여 다상 DFT 필터뱅크의 사용에 있어 제약이 발생할 수 밖에 없다. 본 논문에서는 주파수 도약 환경에서의 비정상적인 다상 DFT 필터뱅크의 과도기 응답을 분석하고 해당 문제를 해결 할 수 있는 방법을 제시하며 모의실험을 통하여 제안된 방법의 효율성을 보인다. Filterbanks have been widely used in the field of multi-channel signal processing for their simple efficient implementation architectures. Especially, the polyphase DFT(Discrete Fourier Transform) filterbank is the most preferred filterbank for the uniform spaced multi-channel processing due to its simplicity. In frequency hopped communication systems, however, the use of the polyphase DFT filterbank is limited due to its undesirable transient response from hop-to-hop transitions. In this paper, the transient response of polyphase DFT filterbanks in the hop-to-hop transition was analyzed, and the efficient methods to overcome such a problem was proposed. Simulation results showed that the proposed schemes could resolve this issue efficiently.
이대회(Lee, Dae-Hee),김성희(Kim, Sung-Hee) SH도시연구원 2013 주택도시연구 Vol.3 No.1
The objectives of this purpose are to establish a maintenance system for residents of public rental housing and provide them with quality maintenance service by investigating the actual state of facilities used by them. A questionnaire survey was conducted on residents of 12 public rental housing complex located in Seoul, Korea, and 1,002 valid samples were secured. The implications derived from the questionnaire survey are as follows: First, in order to delay the deterioration of public rental housing and maintain comfortable residential environment, residents and management offices should enhance regular inspection activities of facilities as an active subject. Second, it is necessary to enable residents to make a decision about repairing facilities autonomously within the reasonable scope that facilities are not damaged by introducing collective repair services residents want. Third, it is necessary to establish maintenance and repair system focused not on repair companies but on residents in the delivery system of repair services.
주행정보를 이용한 플러그인 하이브리드 자동차의 동력원 최적제어
이대흥(Daeheung Lee),정종렬(Jongryeol Jeong),서호원(Howon Seo),차석원(Sukwon Cha) 한국자동차공학회 2011 한국자동차공학회 학술대회 및 전시회 Vol.2011 No.11
Optimization based control methods for Plug-in hybrid electric vehicles require the knowledge of an entire driving cycle and an elevation profile to obtain optimal performance. In this paper, the method using ITS information for prediction of the future driving cycle, and the optimal control strategy based on Pontryagin’s Minimum Principle (PMP) are investigated in order to minimize fuel consumption on the trip distance. To predict future driving patterns, Dynamic Programming theory is proposed for the calculation of the vehicle speed with respect to the driving distance with ITS information. Simulation results show that this approach guarantees the best performance under reasonable condition and the minimization of the fuel consumption on the trip distance between origin and destination.