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Dependence of galaxy properties on void filament straightness

  • Shim, Junsup;Lee, Jounghun;Hoyle, Fiona
    • The Bulletin of The Korean Astronomical Society
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    • v.40 no.1
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    • pp.44.4-45
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    • 2015
  • We investigate the properties of galaxies belonging to the filaments in cosmic void regions, using the void catalogue constructed by Pan et al. (2012) from the SDSS DR7. To identify galaxy filaments within a void, voids with 30 or more galaxies are selected as a sample. We identify 3067 filaments in 1050 voids by applying the filament finding algorithm based on minimal spanning tree and reducing processes to spatial distribution of the void galaxies. We study the correlations between galaxy properties and the specific size of filament which quantifies the degree of the filament straightness. For example, the average magnitude and the magnitude of the faintest galaxy in filament decrease as the straightness of the filament increases. We also find that the correlations become stronger in rich filaments than in poor ones with fewer member galaxies. We discuss a physical explanation to our findings and their cosmological implications.

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Catalogue of the Pyralidae of Korea (Lepidoptera) II. Crambinae and Nymphulinae (한국산 명나방과 목록 II. 포충나방아과, 물명나방아과)

  • Park K. T.
    • Korean journal of applied entomology
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    • v.19 no.3 s.44
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    • pp.181-185
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    • 1980
  • 본지 제18권제2호(1979)에 제1보로 발표된 Evergestiinae와 Pyraustinae(새들명나방아과 및 들명나방아과) 목록에 이어 포충나방아과와 물명나방아과의 목록을 제2보로 발표한다. 포충나방아과는 일명 벼명나방 무리로 불리워지기도 하나 그들의 기주식물이 모두 벼(水稻)와 연관되는 것으로 오인될 우려가 크므로 필자는 전자를 따라 포충나방아과로 명명하였으며 종들의 이름도 이에 준하여 일부 개칭(改稱)하였다. 한국동물명집(2) 곤충편에는 나방아과에 19종이 수록되어 있으나 최근 필자등에 의하여 발표된 종들을 종합하여 본 목록에는 30종이 포함되었으며 물명나방아과에는 13종이 수록되었다.

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Content-based Video Information Retrieval and Streaming System using Viewpoint Invariant Regions

  • Park, Jong-an
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.2 no.1
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    • pp.43-50
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    • 2009
  • This paper caters the need of acquiring the principal objects, characters, and scenes from a video in order to entertain the image based query. The movie frames are divided into frames with 2D representative images called "key frames". Various regions in a key frame are marked as key objects according to their textures and shapes. These key objects serve as a catalogue of regions to be searched and matched from rest of the movie, using viewpoint invariant regions calculation, providing the location, size, and orientation of all the objects occurring in the movie in the form of a set of structures collaborating as video profile. The profile provides information about occurrences of every single key object from every frame of the movie it exists in. This information can further ease streaming of objects over various network-based viewing qualities. Hence, the method provides an effective reduced profiling approach of automatic logging and viewing information through query by example (QBE) procedure, and deals with video streaming issues at the same time.

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ABSOLUTE PARAMETERS AND MASS-RADIUS-LUMINOSITY RELATIONS FOR THE SUB-TYPES OF W UMα BINARIES

  • AWADALLA N. S.;HANNA M. A.
    • Journal of The Korean Astronomical Society
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    • v.38 no.2
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    • pp.43-57
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    • 2005
  • The authors have assembled a sample of 80 W UMa binary systems (42 W-subtype and 38 A-subtype) whose light curves have all been solved by means of the recent W-D code and combined with up-to-date radial velocity solutions. The absolute parameters (masses, radii and luminosities) have been derived (without any constraint on the physical parameters). The main results of this paper are: (1) the mass-luminosity relations for both W&A-subtypes. as well as for all W UMa contact binaries have been shown, (2) the mass-radius relations have been found for both subtypes, (3) some remarks on the evolution status have been presented.

A Study of Halo-Galaxy Correspondence from the Horizon Run 4

  • Park, Jisook;Kim, Juhan;Park, Changbom;Kim, Sungsoo S.
    • The Bulletin of The Korean Astronomical Society
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    • v.40 no.2
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    • pp.50.2-50.2
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    • 2015
  • The Horizon Run 4 is a huge cosmological simulation intended for the study of evolution of dark matter halos in a side of volume of 3150 h-1 Mpc. Using the halo merger trees of most bound particles, we test various models on the survivals of satellites in clusters and will compare them with observed satellite galaxies in a one-to-one correspondence model. We estimate the abundances of central and satellite subhalos, and compare them with the SDSS main-galaxy group catalogue provided by Tempel et al. (2014). Based on these comparisons we will study the mass-to-light relations, environmental effects on morphology and luminosity function, halo occupations in clusters, and nonlinear dynamics of clusters of galaxies.

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Star formation efficiency of galaxies in groups and clusters

  • Jung, Su-Jin;Shim, Hyunjin
    • The Bulletin of The Korean Astronomical Society
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    • v.38 no.2
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    • pp.55.2-55.2
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    • 2013
  • We examine the effect of environment on star formation activity of a sample of a galaxy group catalogue constructed from the Sloan Digital Sky Survey(SDSS DR8) given in Tempel et al.(2012). As an environmental parameter, we use the richness of the galaxy group. According to this parameter, we select 6846 galaxies in dense environment and 297335 galaxies in low environment. By comparing the two samples, we identify the different relationship between star formation rate and stellar mass. In order to compare galaxies in different environment, we fixed other parameters(color, apparent magnitude), which can affect star formation efficiency except for stellar mass. Also, based on HI mass from the ALFALFA survey, we study the environmental dependence of Kennicutt-Schmidt law which show the correlation between star formation rate and gas content.

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Reviews on Korean Geological Nomenclature (지질학용어의 표기법에 대하여)

  • Sang, Ki Nam;Chung, Won Woo
    • Economic and Environmental Geology
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    • v.21 no.4
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    • pp.401-406
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    • 1988
  • Korean geological terms were first used in Hoso dynasty (A. D. 699) and a catalogue of Korean minerals was published on the basis of the Japanese naming in 1915 as nearly 60 species. Korean geological nomenclature was published about 2000 terms in 1963. In recently year, Normally the leading language was English: equivalent were gives in Germany. Chinese and Japanese in the geological field and multitude of new terms. Although, Korean geological nomenclature were many complication of multilingual has become a traditional occupation of geologist and related field. The purpose of this reviews is to comparing about Korean naming and Japanese naming in the historical background, in addition to valid geological terms in Korean and Japanese synonyms.

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A Study on Transmission Methods for Multimedia Data (멀티미디어 데이터의 효율적인 전송기법에 관한 연구)

  • Oh, Jong-Oh;Park, Sei-Seung
    • Journal of the Korea Computer Industry Society
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    • v.5 no.9
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    • pp.873-882
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    • 2004
  • Multimedia database system can be improve data transferring efficiency by consulting catalogue database which is storing the object and serving multimedia meta-database and perform the pre-scheduling for data transferring and by delaying of transferring to reduce the responding timeand reordering the data by various method of transferring. By Introducing these techniques we can enhance the server resources utilizing, minimizing the users responding time and can decrease failure at the scheduling itself and easily search and transfer the information that the user wanted. Like this, the importance of multimedia information treating skill and efficient management are widely recognized and expected lots of research and development to form a butter efficient multimedia database syst

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A bibliographical study on the mathematical materials that were published during Yi-Dynasty (조선시대 산법서류의 서지적 분석)

  • 이노국
    • Journal of Korean Library and Information Science Society
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    • v.21
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    • pp.431-457
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    • 1994
  • The aim of this thesis is to attempt a bibliographical analysis of mathematical materials that were published during Yi-Dynasty. In this study, matters that were treated concretely are the same as follows: 1. Formulation of a system about mathematical materials that were published from Three Kingdoms to Yi-Dynasty. 2. Background of each period about compilation and publication of mathematical materials. 3. Investigation to transition, block book and domain of subject of mathematical materials through analysis on each period of publication. But it was not easy to contrast materials on each catalogue with existed books one by one. In further, we must a new chance for better a n.0, ppreciation about Yi-Dynasty's mathematical materials through continuous studies to this field.

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A New Pivot Algorithm for Star Identification

  • Nah, Jakyoung;Yi, Yu;Kim, Yong Ha
    • Journal of Astronomy and Space Sciences
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    • v.31 no.3
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    • pp.205-214
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    • 2014
  • In this study, a star identification algorithm which utilizes pivot patterns instead of apparent magnitude information was developed. The new star identification algorithm consists of two steps of recognition process. In the first step, the brightest star in a sensor image is identified using the orientation of brightness between two stars as recognition information. In the second step, cell indexes are used as new recognition information to identify dimmer stars, which are derived from the brightest star already identified. If we use the cell index information, we can search over limited portion of the star catalogue database, which enables the faster identification of dimmer stars. The new pivot algorithm does not require calibrations on the apparent magnitude of a star but it shows robust characteristics on the errors of apparent magnitude compared to conventional pivot algorithms which require the apparent magnitude information.