• Ocean Science Journal
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• v.43 no.4
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• pp.165-173
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• 2008

In this article, we describe a simple yet effective method for insertion of observational datasets in a mesoscale atmospheric model used in one-dimensional configuration through Nudging. To demonstrate the effectiveness of this technique, vertical profiles of meteorological parameters obtained from GLASS Sonde launches from a tiny island of Kaashidhoo in the Republic of Maldives are injected in a mesoscale atmospheric model - Advanced Regional Prediction System (ARPS), and model simulated parameters are compared with the available observational datasets. Analysis of one-time nudging in the model simulations over Kaashidhoo show that incorporation of this technique reasonably improves the model simulations within a time domain of +6 to +12 Hrs, while its impact on +18 Hrs simulations and beyond becomes literally null.

• Korean Journal of Human Ecology
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• v.21 no.2
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• pp.197-211
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• 2012

This purpose of this study was to explore the meaning and significance of experiences encountered by preservice teachers' during their observational practicum at day care centers. This study involved one cohort of 32 junior students who were majoring in early childhood education at a 4-year university. Data was analyzed using qualitative research methodology. The findings were as follows: 1) the meaning and significance of students'experiences related to observing children was to develop a trusting relationship with children and a cooperative relationship with teachers in an unfamiliar context. 2) the meaning and significance of students'experiences in observing children was to understand the children and their circumstance. 3) the meaning and significance of students'experience in observing children was to understand the importance of listening in child-teacher spoken interaction.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.1
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• pp.70.2-70.2
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• 2015

Scientific collaborations and observational programs have been on-going between astronomers in Korea and the Steward Observatory/University of Arizona. I will present such existing collaboration models/examples between research groups or individuals and astronomers in KASI or in other institutions and universities in Korea. Building on existing collaborations we would like to further develop opportunities for future scientific collaborations and encourage scholarly exchanges between students, researchers, and faculty members in Korea and Steward Observatory/University of Arizona. In this talk I will also discuss current status of observational programs of Korean astronomers using U of A facilities (MMT and Magellan), as well as successful collaboration examples between Steward Observatory and astronomical institutions in other countries.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.1
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• pp.86.4-87
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• 2015

We will soon complete the installation of 1m telescope at Deokheung Optical Astronomy Observatory (DOAO), National Youth Space Center (NYSC). Before the test observation with NYSC 1m telescope, we present the specs of the 1M telescope and observational conditions of the DOAO site, such as the seeing data at DOAO and the atmospheric extinction coefficients obtained from the observations of standard stars and stellar clusters with 120mm and 150mm refractor in 2014. Since atmospheric extinction coefficients depend on the observational instruments as well as the atmospheric conditions of the site, the improved data with NYSC 1m telescope will be obtained right after the completion of 1M telescope installation. We are planning to invite all astronomers to use 1m telescope for their sciences via regular proposal processes in this year.

• Journal of The Korean Astronomical Society
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• v.37 no.5
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• pp.337-342
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• 2004

The presence of magnetic fields in the intracluster medium in clusters of galaxies has been revealed through several different observational techniques. These fields may be dynamically important in clusters as they will provide additional pressure support to the intracluster medium as well as inhibit transport mechanisms such as thermal conduction. Here, we review the current observational state of Faraday rotation measure studies of the cluster fields. The fields are generally found to be a few to 10 $\mu$G in non-cooling core clusters and ordered on scales of 10 - 20 kpc. Studies of sources at large impact parameters show that the magnetic fields extend from cluster cores to radii of at least 500 kpc. In central regions of cooling core systems the field strengths are often somewhat higher (10 - 40 $\mu$G) and appear to be ordered on smaller scales of a few to 10 kpc. We also review some of the recent work on interpreting Faraday rotation measure observations through theory and numerical simulations. These techniques allow us to build up a much more detailed view of the strength and topology of the fields.

• Journal of The Korean Astronomical Society
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• v.32 no.2
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• pp.119-126
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• 1999

The standard stellar models for $\alpha$ Cen A and B have been constructed without resorting to the arbitrary constraint of the Solar mixing length ratio. Assuming that the chemical compositions and the ages of the two stars are the same, series of models have been constructed. Using the observational constraints, [Z/X], we were able to constrain the number of the 'possible' models. We find that utilizing the observational constraints of [Z/X] the best models for $\alpha$ Cen system are with the initial Z = 0.03, X = 0.66$\~$0.67. In particular, the primary and the secondary stars may have the same mixing length ratio 1.6$\~$1.7, which is the same as that of the calibrated Solar model. And, the age of the system is about 5.4 Gyr. Finally, the large spacing of the p-modes is predicted to be 104 $\pm$ 4$\mu$Hz for $\alpha$ Cen A.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.69-71
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• 2004

DC servo motors have a defect that they need a periodical maintenance because of a brush commutation and also they have a difficulty at high speed operation. In this reason, the use of AC Servo motors are increasing these days. In this paper, a proposed neuro observer is applied to speed control of AC servo motor. The proposed observer complement a problem that occur from increase of gain of High-gain observer in proportion to the square number of observable state variables. And also, the proposed observer can tune the gain obtained by differentiating observational error automatically by using the backpropagation training method to stabilize the observational speed. The excellence and feasibility of the proposed observer is proved by making a comparison test between the proposed observer and the others applied to the same AC servo motor.

• Publications of The Korean Astronomical Society
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• v.10 no.1
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• pp.135-146
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• 1995

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.

• Bulletin of the Korean Space Science Society
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• 2004.04a
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• pp.94-94
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• 2004

We report an investigation of BOES imaging performance variation against observational variables. Average FWHM of the ThAr reference spectra recorded in 10 spectral image frames observed during the night of January 5th, 2004 was computed. The averaged FWHM data was then correlated with observational variables including telescope altitude, air mass, focus position, exposure time, detector temperature, gain settings and S/N ratio. (omitted)

• Journal of Astronomy and Space Sciences
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• v.5 no.1
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• pp.57-72
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• 1988

The long-term observational properties of the photometric behaviors of the short period(p=0.48 day) eclipsing binary system XY UMa are discussed. They are based on the UBV observatins, which were carried out by Geyer in the yaers 1955-1961, 1968, 1975-1984. Light curves of XY UMa revealed very large changes not only between consecutive observing nights, but also from season to season. Between 1955 and 1984, the mean system brightness increased about 30% during this time interfvals, meanwhile, the orbital period of this system was constant whithin 1.6% of its period. The colour index curve shows similar variations like the light curve but with a phase offset oscillation around the time instants of the primary minama. Observational evidence for photospheric and chromospheric activities on the XY Uma are also discussed.