• 제목/요약/키워드: Sky

검색결과 1,464건 처리시간 0.027초

Retrieval of LIDAR Aerosol Parameter Using Sun/Sky Radiometer at Gangneung, Korea

  • Shin, Sung-Kyun;Lee, Kwon-Ho;Lee, Kyu-Tae
    • Current Optics and Photonics
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    • 제1권3호
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    • pp.175-185
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    • 2017
  • The aerosol optical properties such as depolarization ratio (${\delta}$) and aerosol extinction-to-backscatter ratios (S, LIDAR ratio) and ${\AA}ngstr{\ddot{o}m$ exponent (${\AA}$) derived from measurement with AERONET sun/sky radiometer at Gangneung-Wonju National University (GWNU), Gangneung, Korea ($37.77^{\circ}N$, $128.87^{\circ}E$) during a winter season (December 2014 - February 2015) are presented. The PM concentration measurements are conducted simultaneously and used to identify the high-PM events. The observation period was divided into three cases according to the PM concentrations. We analysed the ${\delta}$, S, and ${\AA}$ during these high PM-events. These aerosol optical properties are calculated by the sun/sky radiometer data and used to classify a type of aerosols (e.g., dust, anthropogenic pollution). The higher values of ${\delta}$ with lower values of S and ${\AA}$ were measured for the dust particles. The mean values of ${\delta}$, S, and ${\AA}$ at 440-870 nm wavelength pair (${\AA}_{440-870}$) for the Asia dust were 0.19-0.24, 36-56 sr, and 0.48, respectively. The anthropogenic aerosol plumes are distinguished with the lower values of ${\delta}$ and higher values of ${\AA}$. The mean values of spectral ${\delta}$ and ${\AA}_{440-870}$ for this case varied 0.06-0.16 and 1.33-1.39, respectively. We found that aerosol columnar optical properties obtained from the sun/sky radiometer measurement are useful to identify the aerosol type. Moreover, the columnar aerosol optical properties calculated based on sun/sky radiometer measurements such as ${\delta}$, S, and ${\AA}$ will be further used for the validation of aerosol parameters obtained from LIDAR observation as well as for quantification of the air quality.

DIGITIZED SKY SURVEY I 자료의 검색 DB 구축 (CONSTRUCTION OF DATABASE FOR THE DIGITIZED SKY SURVEY I DATA)

  • 성현일;;김상철;김봉규;임인성;안영숙;손상모;양홍진
    • 천문학논총
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    • 제20권1호
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    • pp.55-62
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    • 2005
  • The First Generation Digitized Sky Survey (DSS-I) is a collection of digitized photographic atlases of the night sky taken from the Palomar Observatory (northen sky) and the Anglo-Australian Observatory (southern sky). DSS-I is widely used by the astronomical community for a number of applications including object cross-identification and astrometry. However, accessing and retrieving the actual images are nontrivial owing to the huge size (> 60 GB) of the dataset. To facilitate retrieval process of DSS-I data for the public, Korean Astronomical Data Center (KADC) developed a web application that provides not only data retrieval but also visualization functions. The web application consists of several modules developed using Java Applet, Jave Servlet, and JaveServer Pages (JSP) technologies. It allows users to retrieve images efficiently in various formats such as FITS, JPEG, GIF, and TIFF, and also offers an interactive visulization tool, ImgViewer, for displaying/analyzing FITS images. To use the web application, users require a Java-enabled web browser.

유효시간 데이터 스트림에서의 스카이라인 질의 알고리즘 (Efficient Skyline Computation on Time-Interval Data Streams)

  • 박남훈;장중혁
    • 한국산학기술학회논문지
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    • 제13권1호
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    • pp.370-381
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    • 2012
  • 다기준 의사결정 연구는 평가기준이 상이한 다수의 선호도로부터 최선의 대안을 찾는 방법으로 실시간 재난 탐지, 센서를 이용한 서식 모니터링 등의 응용환경에서 활용되어 왔다. 최근 유효시간 데이터 스트림 응용환경에서 각 객체들이 개개의 유효시간을 가지므로, 기존의 슬라이딩 윈도우보다 다기준 의사결정 방법, 즉 스카이라인 질의 수행에 더 많은 연산이 필요한다. 본 연구에서는 유효시간 데이터 스트림에서 스카이라인 질의를 수행하는 TI-Sky 알고리즘을 제시한다. 실시간 환경에서 새로운 객체가 생성되고 소멸되기까지 유효한 객체들을 관리하고 스카이라인 질의를 수행하기 위해 파티션단위의 시간 지배관계를 제시한다. 객체의 생성과 유효시간, 지배관계에 따라 시간지배관계를 갱신하며 다양한 방법으로 사멸객체를 제거하여 수행성능을 향상 시켰다. 실험을 통해 TI-Sky가 다양한 데이터 상에서 기존 연구보다 뛰어난 성능으로 스카이라인 질의를 수행하는 것을 증명하였다.

드라마 「SKY 캐슬」에 나타난 아버지와 어머니의 문지기 유형 (Types of Parental Gatekeeping in Drama 「SKY Castle」)

  • 이영환
    • 한국콘텐츠학회논문지
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    • 제20권1호
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    • pp.593-604
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    • 2020
  • 본 연구는 드라마 「SKY 캐슬」에 등장하는 두 가족을 대상으로 3차원 문지기 행동(통제-격려-비난)과 문지기 유형을 분석하였다. 이론상으로 가능한 8개의 문지기 유형 중 드라마 「SKY 캐슬」에서 가장 많이 묘사된 전통적 차단자 유형 이다. 드라마의 한서지과 같은 전통적 차단자 유형의 어머니는 자녀양육에 참여하려는 아버지에게 힘든 상황을 만들기도 하지만, 참여에 관심이 없는 강준상과 같은 아버지는 이를 환영할 수 있다. 또한 아버지 차민혁의 강압적이고 독재적 양육에 대항하여 어머니 노승혜는 자녀를 보호하기 위하여 차단 전략을 사용하면서 이혼까지 감행하고자 하였다. 한편 드라마 「SKY 캐슬」의 결말에서는 가족의 갈등이 해결되어가는 과정으로서 촉진적 개방자 문지기유형을 제시하였다. 즉 한서진과 노승혜는 아버지의 참여를 제지하기 보다 격려하고 지지하면서 통제를 효과적으로 사용함으로써 부부가 서로를 모니터링하면서 양육에 함께 참여하는 촉진적 개방자로 변화된 것이다.

공간(空間)과 천지(天地) - 동서양 건축에서의 공간관 - (Space(空問) and Sky-Earth(天地) - View of Space in the Architectures of the East and the West -)

  • 김성우
    • 건축역사연구
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    • 제14권4호
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    • pp.7-28
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    • 2005
  • We are so used to the concept of the term 'space' that we do not question its conceptual validity. However, this paper argues that the notion of space prevailing all over the world, is not a universal concept that can be applicable to all architectures of the world, but is a particular concept that is generated from the Western way of thinking. This paper alms to identify the conceptual structure of the idea of space as it is originated in the tradition of the West, and, as an alternative view of space, tries to identify the nature of the view of space perceived in the tradition of the Eastern architecture. Comparison of the two views, that of the East and the West, and their meaning in the future of architecture, is another task to discuss in this paper. To be able to clarify the meaning of space in East Asian tradition, a set of new perspective of understanding of space was invited. They are ; 1. sky-earth(天地); insisting that the notion of space should be replaced within the context of sky, which is one half of sky-earth totality 2. energy of the air (空氣), space is not empty part inside of a building, but is a dynamic condition of air that is a part of the sky which always exist in form of energy 3. place(자리): instead of space, which, basically. is a man-made concept, idea of place is necessary, which include not only space but also earth Such concept of space which is different from the notion of space of the West, is meaningful not only to identify the idea of space in the East, but also to be able to contribute for more dynamic, varied, and balanced understanding of space.

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Alternative analytic method for computing mean observation time in space-telescopes with spin-precession attitude motion

  • Juan, Bermejo-Ballesteros;Javier, Cubas;Francisco, Casas;Enrique, Martinez-Gonzalez
    • Advances in aircraft and spacecraft science
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    • 제9권5호
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    • pp.449-462
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    • 2022
  • Space-telescopes placed in the Sun-Earth second Lagrange point (L2) observe the sky following a scan strategy that is usually based on a spin-precession motion. Knowing which regions of the sky will be more observed by the instrument is important for the science operations and the instrument calibration. Computing sky observation parameters numerically (discretizing time and the sky) can consume large amounts of time and computational resources, especially when high resolution isrequired.This problem becomesmore critical if quantities are evaluated at detector level instead of considering the instrument entire Field of View (FoV). In previous studies, the authors have derived analytic solutions for quantities that characterize the observation of each point in the sky in terms of observation time according to the scan strategy parameters and the instrument FoV. Analytic solutions allow to obtain results faster than using numerical methods as well as capture detailed characteristics which can be overseen due to discretization limitations. The original approach is based on the analytic expression of the instrument trace over the sky. Such equations are implicit and thusrequiresthe use of numeric solversto compute the quantities.In this work, a new and simpler approach for computing one ofsuch quantities(mean observation time) is presented.The quantity is first computed for pure spin motion and then the effect of the spin axis precession is incorporated under the assumption that the precession motion is slow compared to the spin motion.In this sense, this new approach further simplifies the analytic approach, sparing the use of numeric solvers, which reduces the complexity of the implementation and the computing time.

수치표고모델, 3차원 카메라이미지자료 및 복사모델을 이용한 Sky Line과 Skyview Factor에 따른 강릉원주대학교 복사관측소 관측환경 분석 (Analysis of Observation Environment with Sky Line and Skyview Factor using Digital Elevation Model (DEM), 3-Dimensional Camera Image and Radiative Transfer Model at Radiation Site, Gangneung-Wonju National University)

  • 지준범;조일성;김부요;이규태;장정필
    • 대기
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    • 제29권1호
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    • pp.61-74
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    • 2019
  • To investigate the observational environment, sky line and skyview factor (SVF) are calculated using a digital elevation model (DEM; 10 m spatial resolution) and 3 dimensional (3D) sky image at radiation site, Gangneung-Wonju National University (GWNU). Solar radiation is calculated using GWNU solar radiation model with and without the sky line and the SVF retrieved from the 3D sky image and DEM. When compared with the maximum sky line elevation from Skyview, the result from 3D camera is higher by $3^{\circ}$ and that from DEM is lower by $7^{\circ}$. The SVF calculated from 3D camera, DEM and Skyview is 0.991, 0.998, and 0.993, respectively. When the solar path is analyzed using astronomical solar map with time, the sky line by 3D camera shield the direct solar radiation up to $14^{\circ}$ with solar altitude at winter solstice. The solar radiation is calculated with minutely, and monthly and annual accumulated using the GWNU model. During the summer and winter solstice, the GWNU radiation site is shielded from direct solar radiation by the west mountain 40 and 60 minutes before sunset, respectively. The monthly difference between plane and real surface is up to $29.18M\;m^{-2}$ with 3D camera in November, while that with DEM is $4.87M\;m^{-2}$ in January. The difference in the annual accumulated solar radiation is $208.50M\;m^{-2}$ (2.65%) and $47.96M\;m^{-2}$ (0.63%) with direct solar radiation and $30.93M\;m^{-2}$ (0.58%) and $3.84M\;m^{-2}$ (0.07%) with global solar radiation, respectively.

AKARI FAR-INFRARED ALL-SKY SURVEY MAPS

  • Doi, Yasuo;Komugi, Shinya;Kawada, Mitsunobu;Takita, Satoshi;Arimatsu, Ko;Ikeda, Norio;Kato, Daisuke;Kitamura, Yoshimi;Nakagawa, Takao;Ootsubo, Takafumi;Morishima, Takahiro;Hattori, Makoto;Tanaka, Masahiro;White, Glenn J.;Etxaluze, Mireya;Shibai, Hiroshi
    • 천문학논총
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    • 제27권4호
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    • pp.111-116
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    • 2012
  • Far-infrared observations provide crucial data for the investigation and characterisation of the properties of dusty material in the Interstellar Medium (ISM), since most of its energy is emitted between ~ 100 and $200{\mu}m$. We present the first all-sky image from a sensitive all-sky survey using the Japanese AKARI satellite, in the wavelength range $50-180{\mu}m$. Covering > 99% of the sky in four photometric bands with four filters centred at $65{\mu}m$, $90{\mu}m$, $140{\mu}m$, and $160{\mu}m$ wavelengths, this achieved spatial resolutions from 1 to 2 arcmin and a detection limit of < 10 MJy $sr^{-1}$, with absolute and relative photometric accuracies of < 20%. All-sky images of the Galactic dust continuum emission enable astronomers to map the large-scale distribution of the diffuse ISM cirrus, to study its thermal dust temperature, emissivity and column density, and to measure the interaction of the Galactic radiation field and embedded objects with the surrounding ISM. In addition to the point source population of stars, protostars, star-forming regions, and galaxies, the high Galactic latitude sky is shown to be covered with a diffuse filamentary-web of dusty emission that traces the potential sites of high latitude star formation. We show that the temperature of dust particles in thermal equilibrium with the ambient interstellar radiation field can be estimated by using $90{\mu}m$, $140{\mu}m$, and $160{\mu}m$ data. The FIR AKARI full-sky maps provide a rich new data set within which astronomers can investigate the distribution of interstellar matter throughout our Galaxy, and beyond.