• Publications of The Korean Astronomical Society
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• v.30 no.2
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• pp.591-592
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• 2015

X1822-371 is a low mass X-ray binary with an accretion disk corona exhibiting partial eclipses and pulsations in the X-ray band. We update its orbital ephemeris by combining new RXTE observations and historical records, with a total time span of 34 years. There were 11 RXTE observations in 2011 but the eclipsing profile can be seen in only 4 of them. The eclipsing center times were obtained by fitting the profile with the same model as previous studies. Combined with the eclipsing center times reported by Iaria et al. (2011), the O-C analysis was processed. A quadratic model was applied to fit the O-C results and produced a mean orbital period derivative of $\dot{P}_{orb}=1.339(25){\times}10^{-10}s/s$, which is slightly smaller than previous records. In addition to the orbital modulation from the orbital profile, we also present our preliminary results for measuring the orbital parameters using the orbital Doppler effect from the pulsation of the neutron star in X1822-371. The updated orbital parameters from eclipsing profiles will be further compared with the ones from pulsar timing.

• Publications of The Korean Astronomical Society
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• v.37 no.3
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• pp.59-79
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• 2022

We investigated the records of astronomical phenomena in the Hyeonjong-Donggung-Ilgi written by the educational office for a crown prince, Sigang-won, during the time of a crown prince of the king Hyeonjong (i.e., from 1649 to 1659). Of the total of 3,625 days, 3,044 astronomical accounts were compiled from astronomical records of 2,003 days. We classified these astronomical accounts into 16 items, grouped into five categories, and statistically analyzed each group. In our analysis, the accounts for atmos-pheric optical phenomena equates to 57.9% of the total, and for celestial phenomena visible during the daytime the percentage is 17.3%. The records related to the approach between two objects such as planets, moon, and stars account for 3.3%, and solar or lunar eclipses take up 0.6%. The ratio of accounts regarding meteor, comet, and fire light (火光) stand at 13.8%, 0.30%, and 6.8%, respectively. Sunny days account for 71.1% of all days per year during this period. We determined that the distribution of the fire light by month is similar to that of the solar halo. We also found that the astronomical records from the Annals of the Joseon Dynasty correspond to only 30% of those of the Hyeonjong-Donggung-Ilgi for the same period. In particular, the phenomena of celestial objects occurring outside the atmosphere are transmitted to the Annals of the Joseon Dynasty in a higher proportion than the phenomena inside the air. It is therefore necessary to use a historical diary like a Donggung-Ilgi to interpret the phenomena in the air such as atmospheric optical events, meteor, and fire light.

• Korean Journal of Social Welfare
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• v.63 no.3
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• pp.239-260
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• 2011

It is very interesting phenomenon that despite a broad consensus on the need for social worker to take cultural aspects into professional practice, thus to be a culturally competent, a number of materials criticising the concept of cultural competence have emerged in these days simultaneously. The main purpose of the study is to clarify such phenomenon, which means that this article is trying to analyze the contents of such critical discourse on cultural competence and the validity of those contents. The result of the study finds out that most of the arguments can be categorized into three aspects: epistemological, ethical, ontological, and that most of the main ideas of the critical discourses have been borrowed from a branch of critical social work theories, especially highly influenced from Foucault and Derrida. This article argues that critical discourses have some significant problems which make a conflict with traditional values and tenets in social work as a human service profession. First, epistemologically, the critical discourse fails to differentiate the matter of discovery from that of justification, which brings the cultural competence to the brink of agnosticism. Second, ethically, insisting that there should be no foundational criteria for cultural hierarchy in term of rightness or goodness, the critical discourses reveal their intrinsic limitations in solving ethical dilemmas and conflict in real world, which can be considered as a kind of evasion of responsibility in disguise of cultural relativism. Third, in practical vein, critical discourses are largely in effective in specifying the concrete model to realize their own ideas, and furthermore they unintentionally promote context-blind perspectives that eclipses the significance of structural and systematical impacts on the cultural identity.

• The Bulletin of The Korean Astronomical Society
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• v.38 no.2
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• pp.71.1-71.1
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• 2013

Among quadruples or higher multiplicity stars, only a few binary systems have been discovered. They are important targets to understand the formation and evolution of multiple stellar systems because we can obtain accurate stellar parameters from photometric and spectroscopic studies. We present the observational results of this kind of rare object 1SWASP J093010.78+533859.5, for which the doubly eclipsing feature had been detected previously from the SuperWASP photometric archive. Individual PSF photometry for two objects with a separation of about 1.9 arcsec was performed for the first time in this study. Our time-series photometric data show that the brighter object A is an Algol-type detached eclipsing binary with an orbital period of 1.3 days and the fainter B is a W UMa-type contact eclipsing binary with a period of 0.23 days. Using the high-resolution optical spectra, we obtained well-defined radial velocity variations of the system A. Furthermore, stationary spectral lines were detected and should have originated from the other stellar component, which was confirmed by the third object contribution from the light curve analysis. No spectral feature of the system B was detected, probably due to its faintness. We obtained the binary parameters and the absolute dimensions from each light curve synthesis. The primary and secondary components of the system A have a spectral type of K1 and K5 main sequences, respectively. Two components of system B have nearly the same type of K3 main sequence. Light variations at out of eclipses were appeared in both systems, interpreting as the effect of stellar spots on these late spectral type stars. We estimated the distances to the systems A and B individually. They may have similar distances of about 70 pc and seem to be gravitationally bound with a separation of about 130 AU. In conclusion, we suggest that 1SWASP J093010.78+533859.5 is a quintuple stellar system with a hierarchical structure of a triple system A(ab)c and a binary system B(ab).

• Journal of Astronomy and Space Sciences
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• v.21 no.4
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• pp.505-528
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• 2004

We have reproduced the records of lunar occultation recorded in the History of Three Kingdoms(삼국사기), the History of the Koryo Dynasty (고려사), the Annals of the Choson Dynasty (朝鮮王朝實錄), the Daily Records of Royal Secretariat of the Choson Dynasty (승정원일기), and obtained the epochs of their realizations. We analysed these results to understand how the system of hours had been kept and when a day began. During most of the periods encompassed by these annals, the 12 double hours(12진각법) and the system of 100 divisions of the day (백각법) had been used when the lunar and the solar eclipses were calculated by royal astronomers. In these systems, the starting point of a day is midnight. On the other hand, the five watch system of hours (경점법), in which a night is divided into five watches, was also used. In this system, a day begins at the sunrise. We found that the traditional twilight, called dusk and dawn (혼명) and used in the east Asian countries, largely corresponds to the nautical twilight in modern concepts. This fact means that the Korean expressions and words for time system in every day life had originated form the five watch system of hours. We pointed out that the sunrise and sunset were convenient boundary lines to ancient astronomers, as well as to farmers in the agricultural society. Our results can be used to determine the exact epoch of each astronomical record in chronicles.

• The Journal of the Korea Contents Association
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• v.21 no.10
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• pp.138-148
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• 2021

In this paper, the basic narrative of The Sweet Home is the story that the residents of the apartment fight and survive the monsters in the isolated circumstances from the outside. This paper analysed the narrative and revealed the characteristics of the NETFLIX drama, The Sweet Home, and dealt with the ethics of contagion, core issue of the drama. Firstly, in the drama Sweet Home, the boundary between the men and the monsters collapses from the contagion. The drama shows the aspects of the apocalyptical world through the optical images, and reveals the main contagion cause is the desire and fury of the human to dominate the others. In the drama, we can see the duality that the characters sometimes stand in solidarity with, and often abuse the others. This story reflects the times after 2000s that the boundary between the man and the monster eclipses. Secondly, the drama shows that the ethics of the others popping up after the contagion is violent and thus can go to the totalitarianism. When the residents are shot by the troopers of the nation, the governmental authority shows its brutality. In this situation, the residents recognize their past behaviors and embrace the others. However, in the point that the characters' selfless behaviors could cover up the complaints and the fury of young generations after 2000s, The Sweet Home is a problematic drama.

• The Journal of Korean Philosophical History
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• no.39
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• pp.53-83
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• 2013

This paper aims to examine how issues related to the heaven-human relation (or nature-culture relation) affected Joseon intellectuals in the eighteenth century by considering Huang Yun Seok as a reference. As a significant indicator, the heaven-human relation issue has traditionally been a critical theme in the history of Confucianism. Since Huang Yun Seok accepted Western Learning based on Zhuxi Learning, he is a good example for examining this issue. Huang's ideas didn't depart too much from Confucianism, but he naturally became interested in Western Learning because of the enthusiastic admiration he had of Ancient Learning since he was a child. Principle-Number was consistent with Ancient Learning and Western Learning, and this was somewhat different from the original notion of numerology. It was used for understanding and explaining astronomical phenomenon. In understanding astronomical phenomenon, Huang used both fact-determined and value-centered approaches. Western astronomy allowed him to make an advance in terms of fact-determined approach while the value-centered approach gave him a portentological perspective on astronomical variation such as solar and lunar eclipses. This indicates one of the ways to keep Zhuxi Learning's identity itself amidst an inflow of new learnings.