• Publications of The Korean Astronomical Society
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• v.9 no.1
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• pp.85-100
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• 1994

In Korea Astronomy Observatory, we developed a S/W package to compile the Korean Nautical Almanac. We describe the motivation to develop the S/W and explain the S/W package in general terms. In appendix, we describe the procedure to calculate the polaris table in more detail. When we developed the S/W, we paid much attention to produce accurate data. We also made great effort to automate the compilation of Nautical Almanac as far as possible, since the compilation is time consuming and labour extensive. As a result, the S/W we developed turns out to be very accurate and efficient to compile Nautical Almanac. In fact, we could compile a Korean Nautical Almanac in a few days.

• Journal of Navigation and Port Research
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• v.30 no.5 s.111
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• pp.363-367
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• 2006

The frequency band $10.5GHz\sim10.7GHz$ provides some of the best angular resolutions using many large and accurate radio telescopes. Developing high performance Bandpass Filter is needed for these equipments to receive low power signals from the space. In this paper, suggests Bandpass Filter for Radio Astronomy equipments. Designed by Microstrip Line for good pass characteristic and suppressing not necessary signals cause of using high frequency. Center frequency is 10.6 GHz and band width is 5% of Center frequency. Manufactured Bandpass Filter is suitable for Radio Astronomy Equipments. Bemuse it matches up to the result by simulate.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.24 no.4
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• pp.495-508
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• 2019

Tidal datums are key and basic information used in fields of navigation, coastal structures' design, maritime boundary delimitation and inundation warning. In Korea, the Approximate Lowest Low Water (ALLW) and the Approximate Highest High Water (AHHW) have been used as levels of tidal datums for depth, coastline and vertical clearances in hydrography and coastal engineering fields. However, recently the major maritime countries including USA, Australia and UK have adopted the Lowest Astronomical Tide (LAT) and the Highest Astronomical Tide (HAT) as the tidal datums. In this study, 1-hr interval 19-year sea level records (1999-2017) observed at 9 tidal observation stations along the west and south coasts of Korea were used to calculate LAT and HAT for each station using 1-minute interval 19-year tidal prediction data yielded through three tidal harmonic methods: 19 year vector average of tidal harmonic constants (Vector Average Method, VA), tidal harmonic analysis on 19 years of continuous data (19-year Method, 19Y) and tidal harmonic analysis on one year of data (1-year Method, 1Y). The calculated LAT and HAT values were quantitatively compared with the ALLW and AHHW values, respectively. The main causes of the difference between them were explored. In this study, we used the UTide, which is capable of conducting 19-year record tidal harmonic analysis and 19 year tidal prediction. Application of the three harmonic methods showed that there were relatively small differences (mostly less than ±1 cm) of the values of LAT and HAT calculated from the VA and 19Y methods, revealing that each method can be mutually and effectively used. In contrast, the standard deviations between LATs and HATs calculated from the 1Y and 19Y methods were 3~7 cm. The LAT (HAT) differences between the 1Y and 19Y methods range from -16.4 to 10.7 cm (-8.2 to 14.3 cm), which are relatively large compared to the LAT and HAT differences between the VA and 19Y methods. The LAT (HAT) values are, on average, 33.6 (46.2) cm lower (higher) than those of ALLW (AHHW) along the west and south coast of Korea. It was found that the S_a and N₂ tides significantly contribute to these differences. In the shallow water constituents dominated area, the M₄ and MS₄ tides also remarkably contribute to them. Differences between the LAT and the ALLW are larger than those between the HAT and the AHHW. The asymmetry occurs because the LAT and HAT are calculated from the amplitudes and phase-lags of 67 harmonic constituents whereas the ALLW and AHHW are based only on the amplitudes of the 4 major harmonic constituents.

• Korean Journal of Environment and Ecology
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• v.28 no.4
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• pp.411-418
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• 2014

This study seeks to identify the effects of light pollution and environmental factors on Great Tits(Parus major) bird's chirping at dawn. For this research, the campus of Sanji University, Wonju, South Korea was selected as the area with light pollution and the western forest of the Chiaksan National Park was chosen as the natural area herein. The Recording period was between March 26th and May 30th, 2014. As a result of analyzing the chirping time according to light pollution, it was found that the light pollution area clearly showed earlier chirping time than the natural area (p<0.05). Great Tits(P. major) normally start their first chirping before sunrise and in most of the days under investigation of this research, those in Sanji University started to chirp earlier. This faster chirping time seems to improve the chance for the female birds to mate with immature males thus, baby birds hatch earlier than the appropriate breeding season and results in the lack of feed resources. The correlation between Great Tits'(P. major) dawn chirping and environmental factors were investigated herein including the time of sunrise, civil twilight, navigation twilight, astronomical twilight, average temperature, highest temperature, lowest temperature, time of moonrise and cloudiness. The first chirping time of wild birds in the day was found to have correlations with all of the environmental factors excluding the time of moonrise and cloudiness. Great Tits(P. major) started their first chirping before sunrise when the day started to break around civil twilight. Along with the earlier sunrise and higher air temperature, their dawn chirping time was also quickened. The time of moonrise and cloudiness did not show a correlation and further follow-up studies will be necessary in this regard.