• 정보관리연구
• /
• 제34권3호
• /
• pp.41-67
• /
• 2003

이 연구는 도서관목록의 역할과 기능이 커다란 변화에 직면하면서 그 본래의 가치보다 훨씬 평가절하되고 있다는 인식에서 출발한다. 이러한 전제 하에, 현재의 상황을 초래한 구조적인 원인을 밝혀내는 것에서부터 시작하여, 현단계 도서관목록이 안고 있는 각종 '부실'을 제거하고 '유용성'을 최대화하기 위해서는 무엇을 어떻게 해야 하는지를 중점적으로 논의해 보고자 하였다. 그리하여 도서관 이용자가 자신의 문제 해결에 도움이 되는 작은 실마리를 찾아낼 수 있는 논리적 경로로써 그동안 도서관목록은 본연의 역할에 얼마나 충실했는지를 검증해 보고자 하였다. 이러한 목적에서, 이 연구는 우리 도서관목록의 유용성이 저하된 근본 원인이 무엇인지를 우선적으로 분석하고, 다음 유용성을 향상시키기 위해서는 향후 무엇을 어떻게 해야 할 것인지를 편목 정책과 실무 방안으로 구분하여 제시하였다.

• 한국정밀공학회지
• /
• 제18권5호
• /
• pp.23-28
• /
• 2001

• 천문학회보
• /
• 제38권2호
• /
• pp.47.1-47.1
• /
• 2013

We present structural parameters of galaxies in the Extended Viro Cluster Catalog (EVCC), new catalog of galaxies in the Viro cluster using homogeneous Sloan Digital Sky Survey (SDSS) Date Release 7 (DR7) data. The EVCC covers more extended region of the Viro cluster than of the Virgo Cluster Catalog (VCC) and presents updated morphologies of galaxies using multi-band images and spectral features. We obtain the surface brightness profiles of galaxies using ellipse task in IRAF. Based on the analysis of surface brightness profile we construct a catalog of various structural parameters of galaxies, i.e. central surface brightness, effective radius, sersic index, effective surface brightness, and mean effective surface brightness. Taking advantage of these structural parameters in various parameter spaces, we refine criteria of dividing giant elliptical and dwarf elliptical galaxies. In addition, we found that bulge dominated galaxies have larger sersic index and brighter central surface brightness than disk dominated galaxies. At fixed magnitude, dwarf elliptical galaxies dwarf lenticular galaxies, and dwarf irregular low surface brightness (LSB) galaxies show larger effective radii than giant elliptical galaxies, giant lenticular galaxies, and irregular high surface brightness (HSB) galaxies, respectively. Dwarf elliptical galaxies and dwarf irregular LSB galaxies occupy the similar structural parameter spaces. We suggest that giant elliptical galaxies and dwarf elliptical galaxies may have different origin.

• 천문학회보
• /
• 제39권2호
• /
• pp.50-50
• /
• 2014

We present a new catalog of galaxies in the wider region of the Virgo cluster, based on the Sloan Digital Sky Survey (SDSS) Data Release 7. The Extended Virgo Cluster Catalog (EVCC) covers an area of 725 deg2 or 60.1 Mpc2. It is 5.2 times larger than the footprint of the classical Virgo Cluster Catalog (VCC) and reaches out to 3.5 times the virial radius of the Virgo cluster. We selected 1324 spectroscopically targeted galaxies with radial velocities less than 3000 km s-1. In addition, 265 galaxies that have been missed in the SDSS spectroscopic survey but have available redshifts in the NASA Extragalactic Database are also included. Our selection process secured a total of 1589 galaxies of which 676 galaxies are not included in the VCC. The certain and possible cluster members are defined by means of redshift comparison with a cluster infall model. We employed two independent and complementary galaxy classification schemes: the traditional morphological classification based on the visual inspection of optical images and a characterization of galaxies from their spectroscopic features. SDSS u, g, r, i, and z passband photometry of all EVCC galaxies was performed using Source Extractor. We compare the EVCC galaxies with the VCC in terms of morphology, spatial distribution, and luminosity function. The EVCC defines a comprehensive galaxy sample covering a wider range in galaxy density that is significantly different from the inner region of the Virgo cluster. It will be the foundation for forthcoming galaxy evolution studies in the extended Virgo cluster region, complementing ongoing and planned Virgo cluster surveys at various wavelengths.

• 천문학회보
• /
• 제40권1호
• /
• pp.74.3-74.3
• /
• 2015

We present 2D- photometric decompositions of ~1,200 nearby dwarf galaxies. Our representative sample is derived from 'A catalog of Visually classified galaxies in the Local Universe'(Ann, Seo and Ha APJS,,,2015) of which galaxy morphological types are determined by visual inspection of color images using the Sloan Digital Sky Survey data release 7. In this catalog, dwarf galaxies were divided into 5 subtypes : dS0, dE, dSph, dEbc, dEblue with distinction of the presence of nucleation in dE, dSph, and dS0. The dSph types are less brighter than other types, and galaxies with nuclei are slightly brighter than those with no nuclei in the same types. Sersic index n have a range 1~1.5, and $dE_{un}$ and $dSph_{un}$ galaxies have n less than 1, and $dSph_n$ galaxies have largest values. We performed two-dimensional decomposition of galaxies using GALFIT, and analyzed their structural components, and residual features which are seen in the residual image.

• 한국비블리아학회지
• /
• 제33권1호
• /
• pp.233-258
• /
• 2022

본 연구의 목적은 교수매체로써 그림책을 탐색하고자 하는 초등학교 교사들의 접근점에 대한 요구를 파악하고 학교도서관 DLS(Digital Library System)의 접근점 개선방안을 제안하는 것이다. 이를 위해 먼저 국내외 7개 도서관 온라인목록시스템에서 제공하는 접근점을 조사하였다. 그리고 초등학교 교사들을 대상으로 온라인 설문조사를 실시하여 최종적으로 220개의 응답을 분석하였다. 분석 결과, 교사들이 가장 필요로 하는 그림책의 접근점은 주제, 학년/연령, 내용, 교과/단원, 범교과학습주제 등으로 나타났다. 이러한 결과를 바탕으로 본 연구는 필요성이 높게 나타난 접근점을 DLS의 목록레코드에서 제공하고, 통제어휘집을 개발하고, 시스템의 기능이나 인터페이스를 개선하여 그림책에 대한 접근성을 향상시키는 방안을 제안하였다.

• 천문학회지
• /
• 제48권1호
• /
• pp.75-82
• /
• 2015

We use a volume-limited sample of quasars in the Sloan Digital Sky Survey (SDSS) DR7 quasar catalog to identify quasar groups and address their statistical significance. This quasar sample has a uniform selection function on the sky and nearly a maximum possible contiguous volume that can be drawn from the DR7 catalog. Quasar groups are identified by using the Friend-of-Friend algorithm with a set of fixed comoving linking lengths. We find that the richness distribution of the richest 100 quasar groups or the size distribution of the largest 100 groups are statistically equivalent with those of randomly-distributed points with the same number density and sky coverage when groups are identified with the linking length of $70h^{-1}Mpc$. It is shown that the large-scale structures like the huge Large Quasar Group (U1.27) reported by Clowes et al. (2013) can be found with high probability even if quasars have no physical clustering, and does not challenge the initially homogeneous cosmological models. Our results are statistically more reliable than those of Nadathur (2013), where the test was made only for the largest quasar group. It is shown that the linking length should be smaller than $50h^{-1}Mpc$ in order for the quasar groups identified in the DR7 catalog not to be dominated by associations of quasars grouped by chance. We present 20 richest quasar groups identified with the linking length of $70h^{-1}Mpc$ for further analyses.

• 천문학회보
• /
• 제41권1호
• /
• pp.35.1-35.1
• /
• 2016

Nearby galaxy clusters and their surrounding regions represent the current endpoint of evolution galaxy cluster evolution. We present a new catalog of 1589 galaxies, what we call Extended Virgo Cluster Catalog (EVCC), in wider area of the Virgo cluster based on the Sloan Digital Sky Survey (SDSS) Data Release 7. The EVCC covers an area 5.2 times larger than the footprint of the classical Virgo Cluster Catalog, and reaches out to 3.5 times the virial radius of the Virgo cluster. The EVCC contains fundamental information such as membership, morphology, and photometric parameters of galaxies. The EVCC defines a comprehensive galaxy sample covering a wider range in galaxy density that is significantly different from the inner region of the Virgo cluster. It will be the foundation for forthcoming galaxy evolution studies in the extended Virgo cluster region, complementing ongoing and planned Virgo cluster surveys at various wavelengths. We also present the large scale structures in the field around the Virgo cluster. We identified seven galaxy filaments and one possible sheet in three dimensions of super-galactic coordinates based on the HyperLEDA database. By examining spatial distribution and Hubble diagram of galaxies, we found that six filaments are directly associated with the main body of the Virgo cluster. On the other hand, one filament and one sheet are structures located at background of the main body of Virgo cluster. The EVCC and the filament structures will be the foundation for forthcoming studies of galaxy evolution in various environments as well as buildup of the galaxy cluster at z ~ 0, complementing ongoing and planned Virgo cluster surveys at various wavelengths.

• 안보군사학연구
• /
• 통권3호
• /
• pp.197-242
• /
• 2005

Active catalog is a kind of digital content that enables consumers to test the functions and features of products from their PCs as if they were using it in real life, by simulating the actions and responses of the product. This new type of interactive digital content can be used extensively to make sales personnel training manuals, sales tools, user manuals and user trouble shooting documents. With active catalogs, companies will be able to compare different designs, show actions according to different functions, and evaluate user reaction to new products without having to produce a single physical prototype or mock-up. At the same time, consumers will be able to understand and 'operate' the product and make well-informed purchase decisions. In this paper, we present a visual event-driven modeling tool, PlayMo, for creating active catalogs, analyze the advantages of using PlayMo, describe the event-driven method used by PlayMo and also introduce two enhanced characteristics of the Event Flow Chart with which the events in PlayMo are structured. Interactive digital content by using the PlayMo3D makes easy, simple and effective design for e-learning, e-catalogue, e-marketing/sales, e-prototyping, customer support, etc. Through its application-ready 3D function visualization solution, engineers and designers can rapidly turn a CAD design model into a 3D interactive virtual product, and the effective function prototyping job can be also completed within a minute.

• 천문학회보
• /
• 제44권2호
• /
• pp.77.2-77.2
• /
• 2019

Measurements of supermassive black hole (SMBH) masses are crucial in studying the co-evolution of SMBHs and their host galaxies. Although reverberation mapping is the most accurate method known to date, this requires spectroscopic monitoring over long periods. Thus, the current sample barely reaches three digits. The virial method, on the other hand, uses emission-line and continuum properties from a single spectrum to estimate the SMBH mass; hence the name single-epoch method. The Sloan Digital Sky Survey (SDSS) has observed spectra of almost all quasi-stellar objects (QSOs) discovered so far. Building on previous studies, using the single-epoch method, we estimate the SMBH masses of more than 500,000 QSOs from the SDSS DR14 Quasar Catalog. This increases the mass-estimated SMBH sample almost by a factor of two, and especially more for the low-mass regime, which was the main target of SDSS-IV (eBOSS).