• Journal of Preventive Medicine and Public Health
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• v.22 no.1 s.25
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• pp.81-89
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• 1989

The authors investigated mortality rate of hospitalized CWP(coal workers' pneumoconiosis) patients. Date, which was composed of age, date of hospitalization, date of death, and radiological findings(profusion of small opacity, type of large opacity, tuberculosis, emphysema, pneumothorax, and cardiac abnormality), was gathered from medical charts and chest x-ray films at the time of hospitalization of CWP patients. Among 738 CWP patients, that were entered survey differently and have followed different period, 160 CWP patients were died during different observational period. Mean value of observational period was 203 weeks, and mean age at hospitalization was 51 years. Because of short observational period, mean survival time could not found. There was statistically significant difference of mortality rate between group of small opacity and that of large opacity. In group of small opacity 5 year survival rate was 0.80 and in group of large opacity that was 0.73. And 80 percentile survival time was 57 months in group of small opacity and that was 40 months in group of large opacity.

• Bulletin of the Korean Space Science Society
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• 2008.10a
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• pp.38.2-38.2
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• 2008

In Korean historical documents, there are a great number of the records for various astronomical events. In particular, historical documents of the Joseon dynasty also have the records containing observational data by an astronomical instrument. However, a quantitative analysis for the accuracy of observational values have never been studied, although there are some studies on the truth of the records themselves. Hence, we investigated observation errors during the period of the Joseon dynasty from the records of Joseon-Wang-Jo-Sil-Lok (the Annals of the Joseon Dynasty) and Seung-Jeong-Won-Il-Gi (Daily Records of the Royal Secretariat). We used the records of the Mars, supernova 1604, and Halley's Comet, and found that observational values before the Hideyoshi invasions in 1592 are relatively more accurate than those after then. However, because the number of cases used in this study is small, we think that more studies are needed to confirm our results. Nonetheless, we reckon our work will be of service to understand astronomical records of the Joseon dynasty.

• Atmosphere
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• v.24 no.1
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• pp.17-27
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• 2014

In this study, the observational environment for sunshine duration at Seoul and Daegu Automated Synoptic Observing Systems (ASOSs) was analyzed using a numerical model. In order to analyze the effects of topography and buildings on observational environment for sunshine duration, the model domains including the elevated building and mountainous areas around Seoul and Daegu ASOSs were considered. Three dimensional topography and buildings used as input data for the numerical model were constructed using a geographic information system (GIS) data. Solar azimuth and altitude angles calculated for the analysis period (one-week for each season in 2008) in this study were validated against those by Korea Astronomy and Space Science Institute (KASI). The starting and ending times of sunshine duration observed at ASOSs largely differed from the respective sunrise and sunset times simply calculated using solar angles and information of ASOSs' latitude and longitude, because uneven topography and elevated buildings around ASOSs cut off sunshine duration right after the sunrise and right before the sunset. The model produced the sunshine indices for Seoul and Daegu ASOSs with the time interval of one minute and the period of one week for each season and we compared the hourly averaged indices with those observed at the ASOSs. One week of which the cloudiness is lowest for each season is selected for analysis. Not only the adjacent buildings but also distant buildings and mountain cut off sunshine duration right after the sunrise and right before the sunset. The buildings and topography cutting off sunshine duration were found for each analyzing date. It was suggested that, in order to evaluate the observational environment for sunshine duration, we need to consider even the information of topography and/or building far away from ASOSs. This study also showed that the analyzing method considering the GIS data is very useful for evaluation of observational environment for sunshine duration.

• 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.

• Publications of The Korean Astronomical Society
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• v.25 no.4
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• pp.107-112
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• 2010

By joining the Giant Magellan Telescope (GMT) project, Korean astronomers will get 10% of the GMT time, starting in the late 2010s. To prepare the GMT era, it is important to evaluate the current observational research activities. We surveyed the research programs performed by domestic astronomers during 2007A - 2010A period, using optical/near - IR telescopes with a medium to large aperture mirror (larger than 4 m). We describe the method and criteria of the survey, and present the results of the analysis based on the collected data.

• Journal of Astronomy and Space Sciences
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• v.36 no.4
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• pp.283-292
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• 2019

The purpose of this study was to develop a period analysis algorithm for detecting new variable stars in the time-series data observed by charge coupled device (CCD). We used the data from a variable star monitoring program of the CBNUO. The R filter data of some magnetic cataclysmic variables observed for more than 20 days were chosen to achieve good statistical results. World Coordinate System (WCS) Tools was used to correct the rotation of the observed images and assign the same IDs to the stars included in the analyzed areas. The developed algorithm was applied to the data of DO Dra, TT Ari, RXSJ1803, and MU Cam. In these fields, we found 13 variable stars, five of which were new variable stars not previously reported. Our period analysis algorithm were tested in the case of observation data mixed with various fields of view because the observations were carried with 2K CCD as well as 4K CCD at the CBNUO. Our results show that variable stars can be detected using our algorithm even with observational data for which the field of view has changed. Our algorithm is useful to detect new variable stars and analyze them based on existing time-series data. The developed algorithm can play an important role as a recycling technique for used data

• Atmosphere
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• v.23 no.1
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• pp.103-112
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• 2013

In this study, we developed a fog classification algorithm to classify fog type based on fog generation mechanism. For the analysis period of 1986-2005, 15,748 fog events had been reported from the 40 observational sites in South Korea. Thus, practically, it is almost impossible to individually classify the fog type of the whole fog events occurred in South Korea manually. In this study, the characteristics of fog during the research period were investigated and the fog classification flowchart were developed base on the analysis, and the fog classification algorithm was applied for the classification of fogs occurred at the observational sites. Finally, the classified fog-type and hindcasted fog occurance results obtained from the flowchart were evaluated for verification.

• Journal of The Korean Astronomical Society
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• v.56 no.2
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• pp.137-147
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• 2023

Shoushili was the official calendrical method promulgated in 1280 CE by the Yuan dynasty. It contains a list of the angular spans in right ascensions for the 28 lunar lodges. They are known to have been measured by Guo Shoujing with his advanced instruments with an unprecedented precision or reading error of 5'. Such precise data are useful to determine their observational epoch with an error range which is narrow enough to pinpoint on which historical occasion they were observed. Using the precise SIMBAD data based on eDR3 of GAIA and carefully identified determinative stars and considering the precession of equinoxes and proper motions, we apply linear regression methods to those data and obtain the observational epoch of 1271 ± 16 CE and the measurement error of 4.1'. We also have polar distances corresponding to declinations written in another manuscript of the Ming dynasty. Since the two data sets have similar significant digits, they were suggested to have the same origin. However, we obtain their observational epoch of 1364±5 CE and the measurement error of 5.7'. They must have been measured with different instruments and on a different occasion from the observations related to Shoushili. We review the history of the calendrical reform during the 13th century in the Yuan dynasty. We conclude that the observational epoch obtained from lodge spans in Shoushili agrees with the period of observations led by Guo Shoujing or 1276-1279 CE, which is also supported by the fact that the ecliptic lodge span values listed in Shoushili were calculated from the equatorial lodge spans.

• Korean Journal of Child Studies
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• v.31 no.4
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• pp.49-60
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• 2010

This study sought to investigate and assess the development patterns of children, aged from 3 to 5, by means of a longitudinal approach. The children's developmental patterns are classified according to five curriculum areas; physical health, social skills, expression, language, and exploration-. The developmental patterns are analyzed in detail according to the observation period, children's ages, and their genders. The subjects consisted of 108 children in A city. A research assistant was asked to observe and keep records of the children's behaviors at three distinct times -early, middle, and late in the school year. The 'observational scale for children' was used as the measurement tool. The data which was thus collected was then subject to statistical analysis. The major findings of the study are as follows. First, there were significant differences in all five curriculum areas according to the children's age and observation period. That is, five-year-old children showed higher scores than three- and four-year-old children. Second, there were significant differences in the social development within five curriculum areas according to the children's gender and the observation period. That is, girls exhibited higher scores than boys.

• Journal of Dental Anesthesia and Pain Medicine
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• v.23 no.2
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• pp.59-67
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• 2023

General anesthesia may influence the postoperative sleep cycle; however, no clinical studies have fully evaluated whether anesthesia causes sleep disturbances during the postoperative period. In this scoping review, we explored the changes in postoperative sleep cycles during surgical procedures or dental treatment under general anesthesia. We compared and evaluated the influence of general anesthesia on sleep cycles and sleep disturbances during the postoperative period in adult and pediatric patients undergoing surgery and/or dental treatment. Literature was retrieved by searching eight public databases. Randomized clinical trials, observational studies, observational case-control studies, and cohort studies were included. Primary outcomes included the incidence of sleep, circadian cycle alterations, and/or sleep disturbances. The search strategy yielded six studies after duplicates were removed. Finally, six clinical trials with 1,044 patients were included. In conclusion, general anesthesia may cause sleep disturbances based on alterations in sleep or the circadian cycle in the postoperative period in patients scheduled for elective surgery.