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        검색결과 275

        183.
        1999.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We have improved the control and driving system of 16' reflector at Kwanak Observatory at Seoul National University, by completing encoder unit, and by developing programs for correction of errors resulting from hardware defects. The hardware defects of this telescope system are the large backlash and the nonuniform tracking and pointing. The telescope pointing accuracy for RA is improved to a few arc minutes, and that for DEC is several tens of arc minutes. The guiding error is improved to 0.7 arcsec/minute, allowing up to 3 minutes exposure for CCD imaging under typical seeing conditions at the Observatory.
        4,000원
        184.
        1999.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We have carried out measurements of 1.2-1.6GHz radio interferences around Seoul Radio Astronomy Observatory located in the campus of Seoul National University. We received interference signals using a pyramidal horn antenna and measured its power using a spectrum analyzer with 1MHz resolution after ~60dB amplification. In order to check the spatial characteristics, we made observations at every 30∘ 30∘ in azimuth at elevation of 30∘and60∘ 30∘and60∘ . Also, in order to check the temporal characteristics, we repeated the all-sky observations five times at every six hours. The results may be summarized as follows: (1) There are strong (≥−20dBm) (≥−20dBm) interferences between 1.2 and 1.4GHz. Particularly strong interferences are observed at 1.271 and 1.281GHz, which have maximum powers of -0.34dBm and -0.56dBm, respectively. (2) The characteristics of the interferences do not depend strongly on directions, although the interferences are in general weak at high elevation and in east-west direction. (3) The interferences appear for a very short (≤0.01s) (≤0.01s) period of time, so that the average power is much smaller than the maximum power. Strong interferences with large (≤−49.0dBm) (≤−49.0dBm) average power have been observed at 1.271, 1.281, 1.339, and 1.576GHz. At these frequencies, the interferences appear repeatedly with a period of ≤0.1s ≤0.1s By analyzing the observed power, we find that, for the strongest 1.271GHz interference, the average intensity is −171dBW/m2/Hz −171dBW/m2/Hz and that the maximum intensity is −122dBW/m2/Hz −122dBW/m2/Hz . If this interference is delivered to the detector without any shielding, then its power would be much greater than the rms noise of a typical line spectrum. Therefore, it is important to shield all the parts of receiver carefully from radio interferences. Also, without appropriate shielding, the sensitivity of a receiver could be limited by the interference.
        4,000원
        186.
        1998.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        3,000원
        187.
        1998.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We have developed solar observational system in the department of Astronomy & Space Sciences of KyungHee University, in order to monitor solar activities and construct solar database for space weather forecasting at maximum of 23rd solar cycle, as well as an solar education and exercise for undergraduate students. Our solar observational system consists of the full disk monitoring system and the regional observation system for H a fine structure. Full disk monitoring system is made of an energy rejection filter, 16cm refractor, video CCD camera and monitor. Monitored data are recorded to VHS video tape and analog output of video CCD can be captured as digital images by the computer with video graphic card. Another system for regional observation of the sun is made of energy rejection filter, 21cm Schmidt-Cassegrain reflector, H a filter with 1.6A pass band width and 375×242 375×242 CCD camera. We can observe H a fine structure in active regions of solar disk and solar limb, by using this system. We have carried out intense solar observations for a test of our system. It is found that Quality of our H a image is as good as that of solar images provided by Space Environmental Center. In this paper, we introduce the basic characteristics of the KyungHee Solar Observation System and result of our solar observations. We hope that our data should be used for space weather forecasting with domestic data of RRL(Radio Research Laboratory) and SOFT(SOlar Flare Telescope).
        4,900원
        194.
        1995.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        8,700원
        195.
        1995.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We have developed a graphic software for image processing of astronomical data obtained by observational equipment in Astronomical Observatory of Kyung Hee University. The essential hardware for running our computer program is simply composed of a PC with the graphic card to handle 256 colors and the color graphic monitor, including CCD camera system. Our software has been programmed in WINDOWS to provide good environments for users, by using various techniques of image processing on astronomical image data recorded in FITS format by KHCCD program(Jin and Kim, 1994) with a compressional mode. We are convinced that our results will be a fundamental and useful technique in the construction of data processing system and can be effectively used in any other observatories, as well as in data processing system of Kyung Hee University.
        4,300원
        196.
        1995.07 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study is concerned with the efficient improvement in the shipboard training of trainees for the marine officers in the future. The shopboard training course is given much weight in the curriculum of the seamanship education for the characteristics of that. In spite of various earlier studies to improve shipboard training system, we don't have desirable one until now on this problem based upon practical and empirical analysis. It seems a matter of urgency should be settled to improve the training environment-training facilities and equipment including simulator education - for the efficient pratice off-shore during training vessels in port. And it is also desired to regulate downward the credit system needed to graduate that trainees should be immersed in their practice without regard to their school records if passed the course during the training period.
        4,500원
        197.
        1994.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We have investigated intensively an optical telescope with 76cm diameter and CCD camera system in astronomical observatory of Kyung Hee university, in order to maximize instrumental functions of our observational equipments and to construct a more reliable photometric system. And computer softwares AUTO DOME, KH CCD and KH PHO for astronomical image observations and their automatic photometries with high accuracy have been made for observers w use our observational system conveniently and efficiently. Throughout careful examinations of these programs, it has been proved that the observing time by our program is shorter than that by manual operations, so that, fast and accurate observations can be executed with ease. For open cluster NGC 7063 observed with S/N value of 350 or more by KH PHO, we have found the magnitude measurements of 11 object stars would show 0.007 magnitude difference, comparing with magnitude data from IRAF/APPHOT. From automatic photometry of eclipsing binary, AB And observed by our software, total 220 data points with good quality have been acquired during 8 hours and so we could make a better light curve than that obtained from any observational results by domestic photoelectric photometry system.
        4,000원