We report the development of a semi-VLBI observation system operating at 21 cm and present the measurement of visibility function toward the sun using this system. The system consists of two 2.3 meter antennas with a maximum separation of 35 meter, a conventional high speed data acquisition system, and a set of programs for software correlation. Since two local oscillators of receiver modules are independent, data had to be fringe-fitted to yield the visibility amplitude. It is found that the visibility amplitude decreases and then bounces back as baseline increases. We confirm that solar disk with brighter limb best explains the measured visibility amplitude.

We carried out CO survey toward IR-excess clouds using SRAO 6-m telescope in search of molecular H2. These clouds, which show far-infrared excess over what is expected from HI column density, are considered to be candidates of molecular clouds. In order to find new high Galactic latitude clouds, we made mapping observations for 14 IR-excess clouds selected from Reach et al.(1998) in 12CO J = 1 - 0 line, supplementing the similar survey in southern hemisphere (Onishi et al. 2001). 12CO emission is detected from three IR-excess clouds among 14 objects. Three newly detected clouds exhibit somewhat clumpy morphology and column densities amount to ~ 1021 cm-2. One of three clouds, DIR120-28, show discrepancy between IR-excess center and CO emission center. It seems that IR-excess may not be an effective tracer of molecular gas. Instead, optical depth(τ) excess, i.e., IR-excess corrected for temperature dependence, may be more effective tracer of molecular clouds, since, by combining statistics from both hemispheres, we found that the detection rate is higher for IR-excess clouds with lower dust temperature.

In an attempt to investigate star formation activity and statistical properties of clumps of high Galactic latitude clouds (HLCs), we mapped the Polaris Flare region, PF121.3+25.5, in 12CO and 13CO J = 1 - 0 using SRAO 6-m telescope and also observed its 12 13CO peak positions in CS J = 2 - 1 with TRAO 14-m telescope. 13CO integrated intensity map shows clearly its clumpy structure and the locations of clumps well agree with 12CO morphology. CS line is not detected toward the 12 13CO peak positions, so we can conclude there are no dense (~ 104 cm-3) in this region. We decomposed 105 clumps from 13CO map using GAUSSCLUMPS algorithm. The mass of clumps ranges from 7.8 M⊙ to 7.4x10-2 with a total mass of 66.4⊙ The mass spectrum follows a power law, dN/dM ∝ M-α with a power index of α =1.91 ± 0.13. The virial masses of clumps are in the range of 10 ~ 100 and so these clumps are considered to be gravitationally unbound.

전자해도 시스템은 2012년 7월 1일 부로 국제항해에 종사하는 선박에 단계별로 설치가 강제화 되었다. 전자해도시스템은 백업장치 를 비치할 경우 종이해도를 대체하여 사용할 수 있는 설비로 선교에서 사용의존도가 높은 핵심항해설비라고 할 수 있다. 현재 전 세계적으로 전자해도 시스템 이용 시 다양한 오류가 발생하고 있으며, 국제해사기구 및 국제수로기구에서도 문제를 인식하고 오류해결을 위한 방안을 모색 하고 있는 중이다. 본 논문에서는 선장 항해사를 포함하는 사용자들을 대상으로 전자해도시스템의 이용 시 오류 발생현황과 정보표시 및 주요 기능 이용 시 개선 요구사항에 관한 설문을 시행하였다. 그 결과를 기반으로 항해안전과 효율측면에서의 ECDIS 기능 개선사항을 제시하였다. 조사에서 사용자들은 ECDIS 기능사용에 있어 대부분 효율성 측면에서는 긍정적으로 평가하였으나 항해안전성에 대한 불안감을 많이 느끼는 것으로 나타났다.