• Title/Summary/Keyword: Stars

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LIGHT-TIME EFFECTS IN TWO ECLIPSING BINARIES V343 AQL AND CX AQR (두 개의 식쌍성 V343 Aql와 CX Aqr의 광시간 효과)

  • Kim, Chun-Hwey;Jeong, Jang-Hae;Lee, Yong-Sam
    • Journal of Astronomy and Space Sciences
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    • v.22 no.2
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    • pp.113-124
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    • 2005
  • All times of minimum light for two eclipsing binaries V343 Aql and CX Aqr were collected and analyzed to study their orbital period variations. It was found that the orbital periods for both stars have varied in a cyclical way superposed on a parabola. A secular period decrease of $-261{\times}10^{-7}$ d/y for V343 Aql was calculated while CX Aqr showed a secular period increase of $+2.55{\times}10^{-8}$8 d/y. Possible causes of secular period variations for two systems were discussed. The cyclical period variation was interpreted as light-time effect due to a third body. The resultant period, semiamplitude and eccentricity of the light time orbit were calculated to be 30.3y, 0.0092d and 0.85, respectively, for V343 Aql and 33.0y, 0.0037d and 0.64, respectively, for CX Aqr. The properties of the third bodies suggested in V343 Aql and CX Aqr systems were discussed.

Discussion of Preliminary Design Review for MIRIS, the Main Payload of STSAT-3

  • Han, Won-Yong;Jin, Ho;Park, Jang-Hyun;Nam, Uk-Won;Yuk, In-Soo;Lee, Sung-Ho;Park, Young-Sik;Park, Sung-Jun;Lee, Dae-Hee;Ree, Chang-H.;Jeong, Woong-Seob;Moon, Bong-Kon;Cha, Sang-Mok;Cho, Seoung-Hyun;Rhee, Seung-Woo;Park, Jong-Oh;Lee, Seung-Heon;Lee, Hyung-Mok;Matsumoto, Toshio
    • Bulletin of the Korean Space Science Society
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    • 2008.10a
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    • pp.27.1-27.1
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    • 2008
  • KASI (Korea Astronomy and Space Science Institute) is developing a compact wide-field survey space telescope system, MIRIS (The Multi-purpose IR Imaging System) to be launched in 2010 as the main payload of the Korea Science and Technology Satellite 3. Through recent System Design Review (SDR) and Preliminary Design Review (PDR), most of the system design concept was reviewed and confirmed. The near IR imaging system adopted short F/2 optics for wide field low resolution observation at wavelength band 0.9~2.0 um minimizing the effect of attitude control system. The mechanical system is composed of a cover, baffle, optics, and detector system using a $256\times256$ Teledyne PICNIC FPA providing a $3.67\times3.67$ degree field of view with a pixel scale of 51.6 arcsec. We designed a support system to minimize heat transfer with Muti-Layer Insulation. The electronics of the MIRIS system is composed of 7 boards including DSP, control, SCIF. Particular attention is being paid to develop mission operation scenario for space observation to minimize IR background radiation from the Earth and Sun. The scientific purpose of MIRIS is to survey the Galactic plane in the emission line of Pa$\alpha$ ($1.88{\mu}m$) and to detect the cosmic infrared background (CIB) radiation. The CIB is being suspected to be originated from the first generation stars of the Universe and we will test this hypothesis by comparing the fluctuations in I (0.9~1.2 um) and H (1.2~2.0 um) bands to search the red shifted Lyman cutoff signature.

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University Green Campus Policy & Evaluation Criteria -Focus on Comparison of Korea, US AASHE, UNEP & ISCN-GULF- (대학 그린캠퍼스 정책과 평가기준에 관한 연구 -한국, 미국 AASHE, UNEP & ISCN-GULF 간 비교를 중심으로-)

  • Oh, Joon-Gul;Yeom, Dae-Bong
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.5
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    • pp.577-586
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    • 2018
  • In Korea, sustainability is mandatory in every field. University campuses are educational facilities that consume considerable amounts of energy. Therefore, many universities have tried to take advantage of the last opportunity to prepare students with sustainability and leadership. This study compared the green campus policy and evaluation criteria among Korea, US AASHE, UNEP, and ISCN-GULF to vitalize the green campus movement and suggest recent research data for the Korea green campus accreditation. The results are as follows: 1. new evaluation criteria need to be added to the certified green building total floor area ratio instead of adapting the G-SEED system in the Campus Resource & Environments category; 2. Korean Green Campus Evaluations need to be improved when expressing the campus individuality by choosing an increased number of credits and criteria; and 3. new evaluation criteria are required to secure the result, feedback, and products from curriculum updates in the Campus Education category.

On the Period Change of the Contact Binary GW Cephei

  • Kim, Chun-Hwey;Song, Mi-Hwa;Yoon, Joh-Na;Jeong, Jang-Hae;Jeoung, Taek-Soo;Kim, Young-Jae;Kim, Jung-Yeb
    • Journal of Astronomy and Space Sciences
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    • v.27 no.2
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    • pp.89-96
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    • 2010
  • BVR CCD observations of GW Cep were made on 15 nights in November through December 2008 with a 1-m reflector at the Jincheon station of the Chungbuk National University Observatory. Nineteen new times of minimum lights for GW Cep were determined and added to a collection of all other times of minima available to us. These data were then intensively analyzed, by reference to an O-C diagram, to deduce the general form of period variation for GW Cep. It was found that the O-C diagram could be interpreted as presenting two different forms of period change: an exclusively quasi-sinusoidal change with a period of 32.6 years and an eccentricity of 0.10; and a quasi-sinusoidal change with a period of 46.2 years and an eccentricity of 0.36 superposed on an upward parabola. Although a final conclusion is somewhat premature at present, the latter seems more plausible because late-type contact binaries allow an inter-exchange of both energy and mass between the component stars. The quasi-sinusoidal characteristics were interpreted in terms of a light-time effect due to an unseen tertiary component. The minimum masses of the tertiary component for both cases were calculated to be nearly the same as the $0.23-0.26M\;{\odot}$-ranges which is hardly detectable in a light curve synthesis. The upward parabolic O-C diagram corresponding to a secular period increase of about $4.12{\times}10^{-8}\;d/yr$ was interpreted as mass being transferred from the lesser to more massive component. The transfer rate for a conservative case was calculated to be about $2.66\;{\times}\;10^{-8}\;M_{\odot}/yr$ which is compatible with other W UMa-type contact binaries.

The Effects of Mongolian Consumer's Lifestyle and Advertisement Properties on Advertisement Behavior of Korean Cosmetics (몽골 소비자 라이프스타일과 광고모델 속성이 한국 화장품 광고태도에 미치는 영향)

  • Batshugar, Uuriintuya;Kim, Kyung-Tae
    • Journal of Distribution Science
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    • v.14 no.8
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    • pp.123-128
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    • 2016
  • Purpose - Korean Wave that overspreads around Asia and America, especially the Korean beauty wave, has reached Mongolia and Mongolian consumers. Mongolia consumers usually prefer foreign cosmetic brands to local brands, because the local brands cannot satisfy fast changing needs and wants of local consumers. Research design, data, and methodology - Based on previous studies about life style of Mongolian consumers, advertisement properties and consumer behaviors, we propose a research model and related hypothesis. In order to test hypotheses, we analyzed 366 survey data out of 376 by eliminating improper 10 responses. Factor analysis and reliability analysis was conducted by SPSS 22.0. We used multiple regression analysis and parameter analysis to test the relation between variables. Results - As exploring the Mongolian consumers' current usage of cosmetic products, we found that the customers' focus is how the products fit with their skin. Mongolian consumers often get the information about cosmetic products through TV and internet. Mongolian consumers show positive attitudes on the appearance of Korean celebrities in responsibility, while there is no significant effect on attractiveness. Mongolian consumer's behaviors toward brand have positive effect on both responsibility and attractiveness of Korean commercial celebrities. Responsibility and attractiveness of Korean commercial celebrities have positive effect on the behaviors toward advertisements of cosmetic products. Conclusions - Behaviors toward advertisements of cosmetic products have positive effect on both purchase intention and loyalty of customer. Responsibility and attractiveness of Korean commercial celebrities have positive effect on mediating variable of behavior toward advertisement and independent variable of purchase intention. Responsibility and attractiveness of Korean commercial celebrities have positive effect on mediating variable of behavior toward advertisement and independent variable of loyalty of customer. In order to improve the effect of advertisements, firms need to consider not only the technique of the model but also the image of model in regard to trust and professionalism appealing to consumers. In addition, firms need to choose the model who fits in with the image of the firms and the products and service of the firms. Finally, Mongolian consumers tend to acquire the shopping information through TV advertisements, especially featuring Korean popular stars, thus, TV advertisements can be a wise option in Mongolian cosmetic market.

SEARCHING MINOR PLANETS AND PHOTOMETRIC QUALITY OF 60cm REFLECTOR IN GIMHAE ASTRONOMICAL OBSERVATORY (김해천문대 60cm 반사망원경의 측광성능 분석과 소행성 탐사)

  • Lee, Sang-Hyun;Kang, Yong-Woo;Lee, Kyung-Hoon
    • Journal of Astronomy and Space Sciences
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    • v.24 no.3
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    • pp.209-218
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    • 2007
  • In this paper, we have presented the observational result for the photometric quality of main telescopes in Gimhae Astronomical Observatory. Also we performed the observation of searching new minor planets as competitive work in public observatories. The observation was carried out using 60cm telescope of Gimhae Astronomical Observatory on 2007 January 13. And, $Sch\ddot{u}ler$ BVI filters and 1K CCD camera (AP8p) were used. To define the quality of CCD photometry, we observed the region of well-known standard stars in the open cluster M67. From observed data, The transformation coefficients and airmass coefficients were obtained, and the accuracy of CCD photometry was investigated. From PSF photometry, we obtained the color-magnitude diagram of M67, and considered the useful magnitude limit and the physical properties of M67. This method can be successfully used to confirm the photometric quality of main telescope in public observatories. To investigate the detection possibility of unknown object as astroid, we observed the near area of the opposition in the ecliptic plane. And we discussed the result. Our result show that it can be possible to detect minor planets in solar system brighter than $V{\sim}18.3mag$. and it can carry out photometric study brighter than V 16mag. in Gimhae Astronomical Observatory. These results imply that the public observatories can make the research work.

An Analysis of Systems Thinking Revealed in Middle School Astronomy Classes: The Case of Science Teachers' Teaching Practices for the Unit of Stars and Universe (중학교 과학 천문 수업에서 나타나는 시스템 사고 분석: 별과 우주 단원에 대한 과학 교사의 교수 실행 사례)

  • Oh, Hyunseok;Lee, Kiyoung;Park, Young-Shin;Maeng, Seungho;Lee, Jeong-A
    • Journal of the Korean earth science society
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    • v.36 no.6
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    • pp.591-608
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    • 2015
  • The purpose of this study was to analyze system thinking revealed in science teachers' teaching practices of middle school astronomy classes. Astronomy lessons were video-taped from four eighth grade science teachers. The video recordings were all transcribed and analyzed by employing a framework for systems thinking analysis after modifying an existing frame of hierarchial structure used in relevant previous studies. In addition, four participants were interviewed in order to uncover their orientation toward teaching using video stimulated recall method. Findings are as follows: All participating teachers were not able to employ the four levels of system thinking appropriately and only utilized the low level of systems thinking. They also demonstrated teacher-centered practices for employing system thinking despite their student-centered orientation toward teaching. The main reason for these results may be that teachers focused more on spatial thinking, than on system thinking as well as the lack of teacher's knowledge about the content and formative assessment of non-earth science teachers. Implications on how to effectively employ the system thinking in astronomy class are discussed in this paper.

A Study on the Iconization of Che Guevara Expressed in Contemporary Fashion (현대 패션에 나타난 체 게바라(Che Guevara)의 아이콘화에 관한 연구)

  • Kim, Hye-Jeong
    • Journal of the Korean Society of Costume
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    • v.56 no.3 s.102
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    • pp.1-11
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    • 2006
  • Che Guevara spearheading the Cuban Revolution was not only the icon as the revolutionary to the New-leftists of the 1960s advocating the ideology of Marxism but, as the cultural revolutionary, had a tremendous influence on the younger generation living in the digital age Che Guevara take on a figure of both the symbol of the Leftist but the romantic revolutionary because he had the external features such as black beret, red stars, military upper jackets and trousers, beard and pipe tobacco. In fact, the symbolic image of Che Guevara was made as the popular image by the avantgarde artists and political vanguard forces of the times under the necessity of Cuban government. Afterwards, the image of Che Guevara has been patronized in making people of aware of the resistant and revolutionary image to capital, power and the power of the media and symbolized as the resistant image to the American capital as well as the revolutionary guerrilla. And his image has continued to be reproduced and symbolized for the commercial and political purposes and as the enthusiastic image of youth culture. This can be seen as having been created as a new image by the popular culture formed by the development of the cyber culture and mass media in the cyberspace shaped by contemporary 'N' generations. The use of Che Guevara's symbolic image was made in the fashion field as well as in the cultural and artistic circles. The borrowing of the icon of Che Guevara represented in a fashion field is attributed to his free spirit, and it can be seen that fashion exists as the vehicle for representing both the symbol system and the sign system containing ideologies and texts as the communicator of resistance to the regime and to social issues. Therefore, this study attempted to investigate the commercial iconization of Che Guevara in the 1990s by comparing the ideology of the symbol in the 1960s and the 1990s and inquire into the borrowing of his image by the fashion domain as well as the fashion worn by him by reference to domestic books and materials on the fashion site. Thereby, this study attempted to make clear that the borrowing of Che Guevara in the realm of fashion since the 1990s not only contained the meaningful interpretation as the symbolic code in the culture of young people living in a digital era but fashion performs an intervening role in the cultural phenomenon.

Comparisons in Pattern Characteristics and Chlorophyll Contents of Major Foliages with Variegated Leaves (주요 반입 관엽식물의 무늬 특징과 엽록소 함량 비교)

  • Park, In Sook;Shin, Yong Gil;Oh, Wook;Kim, Kiu Weon
    • Horticultural Science & Technology
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    • v.31 no.4
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    • pp.447-456
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    • 2013
  • This study was carried out for the establishment of theory and foundational data for breeding, on variegated foliage plants using for potted plants, based on examination and analysis for shape, color, and area ratio of variegated leaves and chlorophyll contents. Six families, 18 genus, and 54 species of variegated plants domestically distributed in Korea were used as the plant materials. Patterns based on chlorophyll-deficient part in variegated leaves were divided into 20 types, such as steps, border, collapsed border, sandy border, half, silk, stars, vein, firewood, border and firewood, center, entirety, leaf, irregular, net, watermelon, melon, and so on. There were 10 kinds of colors including dark green, red, dark red, reddish white, reddish yellow, white, silver, silvery white, yellowish white, and yellow. The ratio of variegated area was ranged from 5.8% to 100% and it was diverse depending on species or cultivar. The ratios by patterns were highest in entirety (98.6%) and relatively high in step (60.8%), whereas, low in boarder, star and firewood (33.6-36.4%), and relatively low in half and vein (43%). Chlorophyll content of variegated leaf was rather lower compared to normal plants and chlorophyll b tended to be higher in ratio of chlorophyll a to b. Particularly content of chlorophyll b in Stromanthe sanguinea 'Triostar', Dracaena fragrans 'Massangeana Compacta', D. reflexa 'Song of India', and Tradescantia spathacea was higher than chlorophyll a in comparison with that of normal plants.

TRAO Multi-beam Legacy Survey of Nearby Filamentary Molecular Clouds : Progress Report

  • Kim, ShinYoung;Chung, Eun Jung;Lee, Chang Won;Myers, Philip C.;Caselli, Paola;Tafalla, Mario;Kim, Gwanjeong;Kim, Miryang;Soam, Archana;Gophinathan, Maheswar;Liu, Tie;Kim, Kyounghee;Kwon, Woojin;Kim, Jongsoo
    • The Bulletin of The Korean Astronomical Society
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    • v.42 no.1
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    • pp.32.1-32.1
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    • 2017
  • To dynamically and chemically understand how filaments, dense cores, and stars form under different environments, we are conducting a systematic mapping survey of nearby molecular clouds using the TRAO 14 m telescope with high ($N_2H^+$ 1-0, $HCO^+$ 1-0, SO 32-21, and $NH_2D$ v=1-0) and low ($^{13}CO$ 1-0, $C^{18}O$ 1-0) density tracers. The goals of this survey are to obtain the velocity distribution of low dense filaments and their dense cores for the study of their origin of the formation, to understand whether the dense cores form from any radial accretion or inward motions toward dense cores from their surrounding filaments, and to study the chemical differentiation of the filaments and the dense cores. Until Feb. 2017, the real OTF observation time is 460 hours. We have almost completed mapping observation with four molecular lines ($^{13}CO$ 1-0, $C^{18}O$ 1-0, $N_2H^+$ 1-0, and $HCO^+$ 1-0) on the five regions of molecular clouds (L1251 of Cepheus, Perseus west, Polaris south, BISTRO region of Serpense, California, and Orion B). The maps of a total area of $7.38deg^2$ for both $^{13}CO$ and $C^{18}O$ lines and $2.19deg^2$ for both $N_2H^+$ and $HCO^+$ lines were obtained. All OTF data were regridded to a cell size of 22 by 22 arcseconds. The $^{13}CO$ and $C^{18}O$ data show the RMS noise level of about 0.22 K and $N_2H^+$ and $HCO^+$ data show about 0.14 K at the velocity resolution of 0.06 km/s. Additional observations will be made on some regions that have not reached the noise level for analysis. We are refining the process for a massive amount of data and the data reduction and analysis are underway. This presentation introduces the overall progress from observations to data processing and the initial analysis results to date.

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