• Title/Summary/Keyword: 상호간섭

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An Effective Frequency Sharing Method using Spectrum Etiquette and Genetic Algorithm for the Coexistence of WRAN and WLAN in TV White Space (TVWS에서 스펙트럼 에티켓 및 GA를 사용한 WRAN과 WLAN의 효율적 주파수 공유기법)

  • Jeong, Won-Sik;Jang, Sung-Jeen;Yong, Seulbaro;Kim, Jae-Moung
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.37 no.2A
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    • pp.83-94
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    • 2012

  • Various wireless communication devices or network such as WRAN and WLAN will coexist in the TVWS(TV White Space). Because of this coexistence, the wireless devices which use the TVWS have to avoid interfering to not only licensed TV receiver and wireless microphone but also homogeneous or heterogeneous TVBD(TV Band Device)s. In this paper, we propose two frequency sharing methods for the coexistence of WLAN and WRAN in terms of interference reduction and throughput enhancement in both homogeneous and heterogeneous networks. One is the WRAN spectrum etiquette to provide more wide bandwidth for WLAN users and the other is the WLAN frequency selection methods to improve the throughput performance. The simulation results have confirmed the throughput improvement of the proposed methods. Moreover, the proposed methods is also applicable to improve the throughput performance and reduce interference of similar systems working in a cognitive manner.

  • https://doi.org/10.7840/KICS.2012.37A.2.83 인용 PDF KSCI

Experimental Study on Interaction of Side-by-Side Moored Vessels (병렬계류 선박의 동유체력 상호간섭에 관한 실험연구)

  • Kim, Jin-Ha;Hong, Sa-Young;Cho, Seok-Gyo;Choi, Yoon-Rak;Song, Myong-Jae;Kim, Duk-Su
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2003.05a
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    • pp.208-213
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    • 2003

  • Recently, Side-by-side mooring system of LNG FPSO and shuttle tanker is one of hot issues in offshore floating body dynamics, which requires accurate analysis of hydrodynamic interactions between side by side moored LNG FPSO and shuttle tanker than tandem moored vessels. This paper aims to investigate basic interaction characteristics of side-by-side moored multiple vessels both numerically and experimentally. A higher-order boundary element method combined with generalized nwde approach will be applied to analysis of motion and drift force of side by side moored multiple-body. Model tests were carried out for the same multiple floating bodies in regular and irregular waves. Motion responses and drift forces of vessels for two mooring situation(coupled & uncoupled) were compared with those of calculations. Discussions will be highlighted on applicability of numerical method to prediction of sophisticated multi-body interaction problem of which motion behavior is very important to analysis of mooring dynamics of deep sea floating bodies.

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Mutual interference suppression of the sinusoidal frequency modulated pulse using SHAPE algorithm (SHAPE 알고리즘을 이용한 사인파 주파수 변조 펄스의 상호간섭 억제)

  • Kim, Guenhwan;Lee, Donghwa
    • Journal of Korea Society of Industrial Information Systems
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    • v.27 no.5
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    • pp.49-59
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    • 2022

  • The SHAPE algorithm has the advantage of being able to shape the pulse spectrum as desired and design it not to distort other characteristics, so it was used in the active sonar pulse design. In this paper, we propose a pulse design using the SHAPE algorithm for a multi-static sonar system to reduce the cross-correlation between frequency-adjacent pulses and prevent the performance degradation of the pulses themselves. The boundary function of the SHAPE algorithm is set to be limited to the pulse bandwidth. As a result of applying the proposed design method to the sinusoidal frequency modulated pulse, the peak cross-correlation level (PCCL), which means the degree of cross-correlation, was reduced by 44.23 dB. Although the PCCL decreased by several tens of dB, no significant change in the ambiguity function was observed, and the integrated sidelobe level (ISL), which means the average value of the side lobe, increased by 11.64 dB.

  • https://doi.org/10.9723/jksiis.2022.27.5.049 인용 PDF KSCI

Multistep Photo-excitation in four-level Atomic Model (네준위 원자 모델에서의 다단계 광여기 현상)

  • 임창환
    • Proceedings of the Optical Society of Korea Conference
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    • 1991.06a
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    • pp.46-49
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    • 1991

  • 우라늄 원자의 선택적 광이온화 과정을 레이저 빔과 상호 작용하는 네준위 원자 모델을 통하여 분석하였다. 다준위 원자 모델이 보이는 원자 감금 현상과 여기 경로의 중첩으로 인한 간섭 현상을 이용하여 모델 내의 최상 준위의 원자 밀도를 최대화하는 조건을 착고, 그 물리적 해석을 부여하였다.

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