• Journal of Astronomy and Space Sciences
• /
• v.11 no.1
• /
• pp.21-30
• /
• 1994

VV Cep-type long period spectroscopic-eclipsing binary AZ Cas has been observed for five years, 1985 Oct~1990 Feb, UBV at the Ilsan Station of Yonsei University Observatory. A total of 431 observations (U=129, B=142 and V=160) are made for 86 nights. Instrumental differential UBV and B-V light curves made with these observations cover phases nearly a half of one period. There is no appreciable light variation in V but in other two passbands a gradual decrease of the brightness is clearly noticed. The loss of light in B resulted in a reddening in $\Delta(B-V)$ by + 0.06 at phases between 0.4~0.5 as compared with that of at phase ~0.1. This intrinsic reddening arouses a question why at the orbital phase of the transit of a hot star in front of a cool M supergiant the heating of the facing hemisphere of M supergiant by the strong radiation from the B stat is absent. With regard to this unusual situation we propose a hypothesis that a large amount of gas stream of low temperature ejected from the surface of M supergiant component towards the B star dominates the brightness of B star and the reflection effect.

• Proceedings of the KSRS Conference
• /
• 2004.10a
• /
• pp.382-385
• /
• 2004

Communication Ocean Meteorological Satellite (COMS) for the hybrid mission of meteorological observation, ocean monitoring, and telecommunication service is planned to be launched onto Geostationary Earth Orbit in 2008 according to the Korea national space program. A feasibility study on the solar constraint in the operation of the COMS meteorological imager (MI) is performed using the GOES imager hardware operation characteristics. The Earth observation areas of the MI are introduced and the observation time of the MI observation area is calculated. The sun light can enter into the MI optical system around the local midnight and impinge on the performance of the MI. The solar eclipse viewed from the satellite occurs near local midnight around the equinox. This study discusses the restriction of imaging operation time that should be considered in order to avoid the solar intrusion about local midnight and to keep acceptable image quality for the MI observation areas. This study could be useful to build the operation concept of the MI during the development of the MI.

• IEMEK Journal of Embedded Systems and Applications
• /
• v.1 no.1
• /
• pp.14-19
• /
• 2006

Integrated development environment (IDE) plays an important role in reducing the developm ent time, thereby improving software development productivity. In recent years, ubiquitous sensor networks (USNs) have become increasingly popular. However their application software is developed mostly using command-line-based tools. Such a development process is not only likely to be error-prone but also inconvenient to debug errors. This paper describes a novel IDE for USN application developers called Nano Esto that provides a single, consistent, and integrated environment for building and executing USN applications. The Nano Esto helps the developers edit and cross-compile source code and download the executable image to the program memory of sensor nodes with just a few button clicks. It also provides support for configuring an application-specific kernel, simulating a wireless sensor network, and estimating power consumption in each sensor node. Currently, Nano Esto runs on Linux as well as on Windows with the same look and feel.

• 한국HCI학회:학술대회논문집
• /
• 2007.02a
• /
• pp.802-807
• /
• 2007

유비쿼터스 컴퓨팅 환경에서 커뮤니티 메타포를 이용하여 유비쿼터스 서비스를 실현하는 커뮤니티 컴퓨팅에 대한 연구가 제안되었다. 제시된 커뮤니티 컴퓨팅 어플리케이션 개발과정은 MDA 개발방법을 적용하여 추상화된 고수준의 모델로부터 최종 플랫폼에 적합한 코드를 생산한다. 그러나 커뮤니티 컴퓨팅 시스템을 구현하기 위한 통합개발환경은 존재하지 않는다. 이에 본 연구에서는 최근 관심이 고조되고 있는 이클립스를 이용하여 커뮤니티 컴퓨팅에서 요구되는 기능들을 플러그인으로 통합하여 커뮤니티 컴퓨팅 어플리케이션 개발에 적합한 통합개발환경(CDTK : Community computing Development Tool Kit)을 제안한다.

• Journal of The Korean Astronomical Society
• /
• v.33 no.3
• /
• pp.177-183
• /
• 2000

We arrange Korean ancient calendar with Solar calendar during Choseon Dynasty(A.D. 1392-1910). In this period, we have one representable history books and several books, and most of information for date are found from them, ChoseonWangjosillok(조선왕조실록) and Jeungbomunheonbigo(증보문헌비고), etc. In those books many astronomical data and calendar information data are contained, so we can make chronological tables. Most of the data are arranged based on those several books, and for doubtable data are identified from eclipse, historical events and lunar phase calculations etc. We find that arranged chronological tables during Choseon Dynasty are similar to that of China and somewhat different from that of Japan. In addition we summarize all misrecorded date data in ChoseonWangjosillok

• Journal of The Korean Astronomical Society
• /
• v.26 no.2
• /
• pp.135-139
• /
• 1993

Events of eclipses as well as other major astronomical events observable in the eastern sector of Asian continent are computed and checked with astronomical records of antiquity. Particular attention was given to two types of the events recorded in remaining records of Dangun Chosun Period (DCP): (1) concentration of major planets near the constellation of Nu-Sung $(\beta\;Aries)$ and (2) a large ebb-tide. We find them most likely to have occurred in real time. i.e., when the positions of the sun, moon, and planets happen to be aligned in the most appropriate position. For solar eclipses data, however, we find among 10 solar eclipse events recorded, only 6 of them are correct up to months, implying its statistical significance is no less insignificant. We therefore conclude that the remaining history books of DCP indeed contains important astronomical records, thereby the real antiquity of the records of DCP cannot be disproved.

• The Bulletin of The Korean Astronomical Society
• /
• v.34 no.2
• /
• pp.30.2-30.2
• /
• 2009

• The Bulletin of The Korean Astronomical Society
• /
• v.42 no.2
• /
• pp.85.3-86
• /
• 2017

We have developed a methodology to determine the coronal electron temperature and solar wind speed using a four filter coronagraph system. The method developed so far have been applied to total eclipse observation and have yielded plausible results. The current methodology starts from the assumption that 1) coronal free electrons are isothermal and 2) coronal free electrons have spherically symmetric distrubution. However, the actual solar corona differs significantly from the two assumptions above. The coronal electron density is not spherically symmetric due to streamers, plumes, and coronal loops, and the electron temperature is also expected to increase rapidly with distance from the sun. We will discuss how to determine the temperature and wind speed of the corona in the case of corona with thermal structures and non-spherical symmetric electron density.

• Research in Mathematical Education
• /
• v.12 no.2
• /
• pp.143-149
• /
• 2008

Before the 14th century, China had been thought as one of the countries with the most developed mathematics all along. But after the 16th century, Chinese mathematics increasingly walked up to the eclipse. The main reasons include the following points. First, the development of neoteric mathematics was closely associated with the social industrialization, but the lags in feudal China seriously blocked the development of the capitalistic seed, and China was still in the agricultural society then and couldn't step into the industrial society, which impeded the development of mathematics concerned with the industry and commerce. Second. the increasingly carrion feudalization was one of the essential reasons to block the development of Chinese neoteric mathematics. Finally, seeing about the developing logics of Chinese neoteric mathematics, we can find it was a scattered and experiential mathematical knowledge without strict and rational self-organizing structure system, which had the limitations existing in its interior mechanism.

• Proceedings of the KIPE Conference
• /
• 2002.07a
• /
• pp.773-776
• /
• 2002

The battery charger of spacecraft has two different modes of operation respectively. One is the bus voltage regulation mode and the other is the charge current regulation mode. And also the battery discharger provide the power during eclipse mode of spacecraft. In this study, a test model of the battery charger and discharger using hi-directional converter are designed and analyzed. These Battery Charger and Discharger is introduced the modular converter method that can be added the converter modules according to the load variation.