• 한국항해항만학회지
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• 제33권1호
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• pp.21-25
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• 2009

선박이 부두에 이접안할 경우 쓰러스터나 특수 추진기가 없는 선박은 예선의 도움을 받아 이접안을 하게 된다. 이접안시 예선들은 도선사의 명령에 의하여 선박의 이접안을 도와주게 된다. 이때 본선과 예선의 위치가 2차원 지도에 표시되고 부두와의 상대적인 거리가 나타난다면 이접안에 매우 도움이 될 것으로 생각된다. 본 연구에서는 이러한 예선사용 지윈 시스템에 대해서 개념 설계를 수행하였다. 예선사용 지원 시스템은 본선, 예선 및 부두의 상황을 모니터링하는 예선사용 모니터링 기능과 해양환경을 고려하여 필요한 예선력을 계산하여 나타내주는 예선사용 자동화 기능을 갖고 있다. 이러한 예선사용 지원 시스템은 항만에 설치된 네트워크를 기반으로 설계되었으며, 추후 한국해양연구원의 선박운항 시뮬레이터를 이용하여 검증될 계획이다.

• 천문학회보
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• 제39권2호
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• pp.71.1-71.1
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• 2014

The black hole occupation fraction in dwarf galaxies can provide an important clue for understanding the black hole seed formation. As a pilot feasibility study, we performed a KVN radio monitoring campaign over 8 months for 4 dwarf galaxies. Two galaxies (IC10 and NGC1569) are detected at 22 GHz, respectively with 39 mJy, 83 mJy. The measured flux (rms) variability is 13% and 8%, respectively for IC10 and NGC1569, while the mean flux uncertainty is 25% and 12%. Thus, the detection of the radio flux variability is at best marginal. Detecting flux variability of faint sources (i.e., 22 GHz flux < 200 mJy) seems challenging with the KVN single dishes. Combining with the 1.4 GHz flux measurements from the NVSS, we find that these two galaxies have a steep spectrum, supporting that the radio sources are AGNs. Instead of a monitoring, single-epoch multi-band observations can be effective for identifying radio AGNs by providing the constraint of the radio continuum slope.

• 천문학회보
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• 제46권1호
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• pp.54.4-55
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• 2021

The Seoul National University AGN Monitoring Project (SAMP) is a welldesigned long-term AGN reverberation mapping project. SAMP focuses on the luminous AGNs out to z~0.5 with relative long time lags between AGN continuum and broad emission lines and aims to probe the high-end of the AGN broad line region (BLR) size-luminosity (R-L) relation. The pilot observations started in October 2015 for 100 AGNs to confirm the variability and the H and [O III] emission line strengths. Based on the initial variability test, 48 quasars has been continued spectroscopic monitoring since Feb. 2016 with Lick 3m and MDM 2.4m telescopes with a cadence of ~20 days. Supporting photometric monitoring in B and V band was conducted at multiple facilities including the MDM 1.3m, LOAO, and DOAO telescopes with a cadence of ~10 days. By the time of Feb. 2021, we have obtained five years spectroscopic and photometric data. More than 30 AGNs shows significant variability in five-year baseline and 16 of them show well detected lags between B-band and H. Here, we report some examples of SAMP light curves and lag detections using the first five-year data as well as the location of our 16 targets in the AGN BLR R-L relation. These measurements are consistent with the existing R-L relation and located at the high-end. With the coming data, SAMP are hopefully to report more AGNs with well detected lags. Our results demonstrate the general feasibility and potential of long-term reverberation project with medium cadence for luminous AGNs.