• Proceedings of the Korea Air Pollution Research Association Conference
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• 2008.04a
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• pp.434-435
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• 2008

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2006.04a
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• pp.104-106
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• 2006

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2006.04a
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• pp.401-403
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• 2006

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2008.10a
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• pp.262-263
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• 2008

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2004.11a
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• pp.337-338
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• 2004

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2004.11a
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• pp.217-219
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• 2004

• Journal of the Korean Institute of Navigation
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• v.22 no.3
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• pp.93-102
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• 1998

This article aims at suggesting a practicla auide to navigation under restricted visibility by a study of an English court. This case os a good example of setting out safe speed. close-quarters situation, safe passing distance as the above factors are not enumerated in Collision Regulations.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2006.10a
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• pp.75-76
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• 2006

• Journal of Advanced Navigation Technology
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• v.22 no.6
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• pp.610-615
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• 2018

Globally, global navigation satellite system (GNSS) is being developed and operated in advanced countries. China's Beidou is developing rapidly, starting with global positioning system (GPS), which is the most representative system. In this paper, we analyze the visibility of Beidou satellite in Korea at present time to utilize rapidly changing Beidou. In this analysis, it is compared with GPS which is stable service. The results of the visibility analysis are based on the results of the mask angle (the low elevation satellite exclusion angle) and the result of the skyplot (a visual representation of the position of the satellite at the user location). Visibility analysis shows that the high elevation angle of Beidou satellite is higher than that of GPS satellite in Korea. In addition, GPS and Beidou's availability and positioning accuracy analysis are performed to confirm the effect of increasing elevation angle satellites. According to the results, Beidou is more effective than GPS in using high elevation satellites in Korea.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.1350-1357
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• 2010

In tunnelling, temporary ventilation is very important factor in the safety of worker and the work efficiency which is affected by visibility. There are a lot of problems in the recent tunnel construction, because the longer the tunnel, the more the present design doesn't satisfy the allowable standard about dust and air pollution. Especially, In case the length of tunnel is more than 1,000m, the ventilation efficiency tends to decrease. In this study, the field measurement of the degree of contamination was performed near the face of tunnel. Based on the results obtained, the main factors of problem in temporary ventilation are the difference of temperature between outside and inside, the rate of leakage of ventilation duct and the dust and so on. It maybe helpful to the solution of problems, and also the accurate ventilation estimate.