• 천문학논총
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• 제34권3호
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• pp.49-65
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• 2019

We investigate the provenance and the changes in the timekeeping system focusing on official records such as almanacs and textbooks published by the government after the solar calendar was introduced. We found that the solar calendar and the 12-hour clock time first appeared in 1884 during Joseon dynasty, at that time the solar calendar was used at the open port in Busan to facilitate the exchanges with Japan. The 12-hour clock time first appeared in the 『Hansung Sunbo』 published by the government in 1884. We also found that the Joseon dynasty also used 12 diǎnzhōng or 12 diǎn. In addition, the term of the 'Sigan' first appeared in the first official academic textbook in August 1895, and the chapter related to time contained the information about 12-hour clock time instead of the 12 Shi. In 1908, the meaning of the solar time, the equation of time, and the differences in longitude with the adoption of Korean Standard Time were introduced. Meanwhile, the 24-hour clock time was first introduced in Joseon and applied to railway times in 1907. The 1946 almanac, the first issue after liberation, used the 12-hour clock time which uses 'Sango', 'Hao' and the 24-hour clock time started to be used from the following year and is still used to this day. Finally, the 12-hour clock time, which was introduced around 1884, was enacted as Article 44 of the law in 1900 and was revised again in 1905 and 1908. In Korea, the terms related to the time in the current astronomical calendar system were newly defined around 1884, 1896, and 1908, and gradually standardized through the establishment of laws.

• Journal of Positioning, Navigation, and Timing
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• 제12권2호
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• pp.167-176
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• 2023

This study presents the performance analysis of real-time orbit determination and prediction for navigation message generation of Regional Navigation Satellite System (RNSS). Since the accuracy of ephemeris and clock correction in navigation message affects the positioning accuracy of the user, it is essential to construct a ground segment that can generate this information precisely when designing a new navigation satellite system. Based on a real-time architecture by an extended Kalman filter, we simulated orbit determination and prediction of RNSS satellites in order to assess the accuracy of orbit and clock prediction and signal-in-space ranging errors (SISRE). As a result of the simulation, the orbit and clock accuracy was at 0.5 m and 2 m levels for 24 hour determination and six hour prediction after the determination, respectively. From the prediction result, we verified that the SISRE of RNSS for six hour prediction was at a 1 m level.

• Interdisciplinary Bio Central
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• 제1권1호
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• pp.5.1-5.4
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• 2009

This article is an addendum to the authors’ previous article (Kim, J. et al. (2008) Plant Cell 20, 307-319). The instrumentation and software described in this article were used to analyze the circadian leaf movement in the previous article. Here, we provide detailed and practical information on the instrumentation and the software. The source code of the LMA program is freely available from the authors. The circadian clock regulates a wide range of cyclic physiological responses with a 24 hour period in most organisms. Rhythmic leaf movement in plants is a typical robust manifestation of rhythms controlled by the circadian clock and has been used to monitor endogenous circadian clock activity. Here, we introduce a relatively easy, inexpensive, and simple approach for measuring leaf movement circadian rhythms using a USB-based web camera, public domain software and a Leaf Movement Assay (LMA) program. The LMA program is a semi-automated tool that enables the user to measure leaf lengths of individual Arabidopsis seedlings from a set of time-series images and generates a wave-form output for leaf rhythm. This is a useful and convenient tool for monitoring the status of a plant's circadian clock without an expensive commercial instrumentation and software.

• 생명과학회지
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• 제22권8호
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• pp.999-1008
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• 2012

자기 현가적(self-sustaining) 조절 장치인 생체시계는 24시간 주기의 생체리듬을 조절하며 또한 생물체로 하여금 매일 변화하는 자연환경의 외부 신호를 인지할 수 있도록 해준다. 생체시계 유전자의 발현 조절은 전사/해독의 역환류 기작을 통해 이루어진다. 애기장대 LATE ELONGATED HYPOCOTYL (LHY)와 CIRCADIAN CLOCK-ASSOCIATED 1 (CCA1)는 아침에 최고조로 발현되며 해독된 LHY and CCA1는 저녁에 최고로 발현되는 TIMING OF CAB EXPRESSION1 (TOC1)의 발현을 억제한다. TOC1단백질은 LHY와 CCA1 발현을 촉진시킴으로써 생체시계의 핵심 진자(oscillator)를 형성한다. 동물에서 생체시계의 주요 전사 인자인CLOCK은 아세틸화효소 활성 기능을 가지며, 이는 생체시계의 기능 유지에 아세틸화의 중요함을 의미한다. 하지만 애기장대 생체시계에 아세틸화를 담당하는 인자에 대한 정보는 현재 보고된 바가 없다. 본 연구에서 DET1 (De-Etiolated1)는 암조건하에서 애기장대 생체시계 관련 핵심인자 중 하나인 LHY발현을 억제하는데 필요하며 이의 억제는 H3Ac 조절을 통해 이루어짐을 증명하였다. 하지만 LHY 아세틸화를 담당하는 효소의 발굴 및 이들 효소와 DET1과의 연결을 찾는 문제는 여전히 미재로 남아있다.

• 천문학회보
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• 제41권1호
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• pp.54.2-54.2
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• 2016

Korea Microlensing Telescope Network (KMTNet) is the first optical survey system of its kind in a way that three KMTNet observatories are longitudinally well-separated, and thus have the benefit of 24-hour continuous monitoring of the southern sky. The wide-field and round-the-clock operation capabilities of this network facility are ideal for survey and the physical characterization of small Solar System bodies. We obtain their orbits, absolute magnitudes (H), three dimensional shape models, spin periods and spin states, activity levels based on the time-series broadband photometry. Their approximate surface mineralogy is also identified using colors and band slopes. The automated observation scheduler, the data pipeline, the dedicated computing facility, related research activity and the team members are collectively called 'DEEP-South' (DEep Ecliptic Patrol of Southern sky). DEEP-South observation is being made during the off-season for exoplanet search, yet part of the telescope time is shared in the period between when the Galactic bulge rises early in the morning and sets early in the evening. We present here the observation mode, strategy, software, test runs, early results, and the future plan of DEEP-South.

• Structural Engineering and Mechanics
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• 제32권1호
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• pp.95-126
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• 2009

The present contribution addresses the parallelization of advanced simulation methods for structural reliability analysis, which have recently been developed for large-scale structures with a high number of uncertain parameters. In particular, the Line Sampling method and the Subset Simulation method are considered. The proposed parallel algorithms exploit the parallelism associated with the possibility to simultaneously perform independent FE analyses. For the Line Sampling method a parallelization scheme is proposed both for the actual sampling process, and for the statistical gradient estimation method used to identify the so-called important direction of the Line Sampling scheme. Two parallelization strategies are investigated for the Subset Simulation method: the first one consists in the embarrassingly parallel advancement of distinct Markov chains; in this case the speedup is bounded by the number of chains advanced simultaneously. The second parallel Subset Simulation algorithm utilizes the concept of speculative computing. Speedup measurements in context with the FE model of a multistory building (24,000 DOFs) show the reduction of the wall-clock time to a very viable amount (<10 minutes for Line Sampling and ${\approx}$ 1 hour for Subset Simulation). The measurements, conducted on clusters of multi-core nodes, also indicate a strong sensitivity of the parallel performance to the load level of the nodes, in terms of the number of simultaneously used cores. This performance degradation is related to memory bottlenecks during the modal analysis required during each FE analysis.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.1
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• pp.171-174
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• 2006

A large number of service providers in countries all over the world have established GNSS reference station networks in the last years and are using network software today to provide a correction stream to the user as a routine service. In current GNSS network processing, all the geometric related information such as ionospheric free carrier phase ambiguities from all stations and satellites, tropospheric effects, orbit errors, receiver and satellite clock errors are estimated in one centralized Kalman filter. Although this approach provides an optimal solution to the estimation problem, however, the processing time increases cubically with the number of reference stations in the network. Until now one single Personal Computer with Pentium 3.06 GHz CPU can only process data from a network consisting of no more than 50 stations in real time. In order to process data for larger networks in real time and to lower the computational load, a federated filter approach can be considered. The main benefit of this approach is that each local filter runs with reduced number of states and the computation time for the whole system increases only linearly with the number of local sensors, thus significantly reduces the computational load compared to the centralized filter approach. This paper presents the technical aspect and performance analysis of the federated filter approach. Test results show that for a network of 100 reference stations, with the centralized approach, the network processing including ionospheric modeling and network ambiguity fixing needs approximately 60 hours to process 24 hours network data in a 3.06 GHz computer, which means it is impossible to run this network in real time. With the federated filter approach, only less than 1 hour is needed, 66 times faster than the centralized filter approach. The availability and reliability of network processing remain at the same high level.

• 대한소아치과학회지
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• 제44권1호
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• pp.64-71
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• 2017

본 연구는 원주세브란스기독병원 응급실에 내원한 소아 환자들의 나이, 성별, 외상 발생 장소, 외상의 원인, 외상의 위치, 외상 후 경과시간, 응급실 내원시간, 처치의 유형 등을 파악하기 위해 시행되었다. 2011년 3월부터 2015년 10월까지 치과적 외상으로 인해 원주세브란스기독병원 외상 센터에 내원한 0 - 15세 사이 841명의 환자들의 정보를 수집하였다. 외상은 남아에서 호발하였으며, 호발하는 나이는 0 - 3세였다. 6세 미만에서는 집에서 외상이 가장 호발하고, 넘어지는 것이 외상의 가장 주된 원인이었다. 하지만 6세 이상에서는 외상의 장소로 집이 크게 줄어들었으며, 외상의 원인으로 넘어지는 것이 줄어들고 스포츠와 기타 원인이 매우 크게 증가하였다. 나이 대 별로 외상의 원인과 장소에서는 유의한 차이를 보였다. 외상의 위치로는 입술과 상악 절치가 가장 많은 빈도수를 보였다. 응급실을 내원하는 시간대로는 18 - 24시(53.3%)에 내원하는 환자가 가장 많았으며, 0 - 6시(4.6%)에 내원하는 환자는 가장 적었다. 외상 후 경과 시간은 1시간 이내가 51.5%, 1 - 2시간이 26.8%, 2 - 3시간이 11.5%로, 3시간 이내에 내원하는 환자가 89.8%에 달했다. 응급에서 행해지는 처치의 유형으로는 경과관찰을 하는 경우가 가장 많았으며, 가장 많이 행해지는 술식은 봉합술이었다. 본 연구를 통해 소아의 치과적 외상과 응급실 방문은 환아의 성별, 나이, 상황에 따라 역학적인 특징을 보인다는 것을 살펴보았다. 외상의 양상은 어린이의 사회, 발달, 생리적인 요인이 종합되어 나타난다.

• 한국직업건강간호학회지
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• 제10권2호
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• pp.174-182
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• 2001

This study was performed to find out the differences between noise levels of hospital wards and the nurses efforts for noise management in some general hospitals. The hospital wards selected were the intensive care unit(ICU), the emergency room(ER), the nursery room(NR), the internal medicine(IM), the general surgery(GS) among the 5 general hospitals located in Seoul. The data were collected from August 3 to September 13, 1999 through questionnaire survey and noise measurement in each nursing station of hospital wards. Data analysis was done by SPSS 8.0 package among the 305 questionnaires and 24 hours monitored noise levels. Frequency, Chi-square and ANOVA test were used. The study results were as belows: 1. The noise level measured by 24 hours monitoring survey were exceeded on the standard limit in all the hospital wards. Data also showed that noise levels were significantly different in each ward among the three shifts working duties. 2. The subjects were all female nurses. They were mostly working in the ICU ward(28.9%). They were 26~30 years old (43.9%), junior college graduates(57.0%), working for 1~5 years(55.1%) as staff-nurse(85.6%). There were no significant differences between hospital wards and general characteristics of nurses. 3. The noise levels perceived by nurses were regarded as 'Highly noisy'(56.4%), especially during the 11:30 and 15:30 (30.2%) o'clock. Data also showed that noise education was not ever given to nurses(89.9%). Nurses also responded that they hardly put an effort to reduce noise level(54.8%). However, there were significant differences between wards and noisy working time, experience of noise education and level of effort for noise reduction. 4. Nurses also perceived the ventilator alarm and EKG-alarm as the most disturbing sounds in the ICU, human voice and telephone ringing in the ER, human voice and EKG-alarming in the NR, human voices and telephone ringing in IM and GS both wards respectively in order. There were significant differences between hospital wards and noise making factors. 5. Nurses were shown that they regarded highly 'Sound reduction of the human voice', 'Careful handling on medical instruments', and 'Immediate appliances on alarming materials' as the practical method for noise management. There were significant differences between hospital wards and behavioral practical efforts for noise management. According to that results, the statistical differences were shown in the 24 hour monitored noise levels in each ward. Also, nurses perceived the noise severity differently and they approached variously on the practical efforts for noise reduction in each ward. Thus, author thinks that concrete and systematic endeavor will be necessary for noise reduction and management in hospitals for better working and healing environment for both of patients and staffs.