• Publications of The Korean Astronomical Society
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• v.30 no.2
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• pp.525-527
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• 2015

We prepare a catalog of the morphological types of 5840 galaxies within z = 0.01. We determine the morphological types by visual inspection using color images from the Sloan Digital Sky Survey (SDSS) DR7. The majority of the sample galaxies are SDSS spectroscopic target galaxies, but we add ~ 900 galaxies whose redshifts are available in the NASA Extra Galactic Database (NED). The fraction of elliptical and lenticular galaxies is ~ 0.06 while spiral galaxies comprise ~ 30% of the sample with a bar fraction of ~ 0.6. About half of sample are dwarf galaxies of which ~ 35% are dwarf elliptical-like galaxies. There is a strong correlation between the morphological types and luminosities of the galaxies, i.e., high luminosities in the early type galaxies and low luminosity in the late type galaxies. The mean luminosity of dwarf elliptical-like galaxies is similar to that of irregular galaxies.

• Proceedings of Korean Society of Archives and Records Management
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• 2019.05a
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• pp.69-74
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• 2019

In the digital environment, electronic records are explosively increasing, but there are little concerns on how to effectively manage and service. On-Nara 2.0 and record management system, the information system of records production and management stage, are being developed and distributed on the cloud base. Archives management system requires the acquisition of new record management techniques because they need to acquire and manage various types of private records as well as public records. In this paper, we will discuss automation and intelligent technologies for archives management.

• Journal of Korean Society of Archives and Records Management
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• v.2 no.1
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• pp.119-131
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• 2002

The study designs and implements a KORMARC/EAD integrated system for the Myongji Digital Library Collections. The purpose of this paper is to design the metadata to Myongji Korean History Collections to provide digital information of high quality to clients, and to develop and implement a model for managing digital library collections. In order to test the model and the quality of the derived metadata, we built a metadata management system, which is connected to the existing KORMARC system. The system consists of two modules- a retrieval and an input module. While in the retrieve mode, one can retrieve KORMARC records of books and archival items, with links to modified EAD files for archival items or to image files for books, in the input mode, one can type two types of data such as a catalog data and an inventory data. Finally, we evaluated the proposed system via mail questionnaires, and propose three suggestions to make this system a much more comprehensive and effective system.

• The Bulletin of The Korean Astronomical Society
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• v.38 no.2
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• pp.41.2-41.2
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• 2013

We present a very wide-field survey of dwarf galaxies in the M106 Group using the Sloan Digital Sky Survey Data Release 8, covering an area of $10^{\circ}{\times}14^{\circ}$ around M106. We select 18 new members of the M106 group, 10 of which are new findings. Surface brightness profiles of most of these galaxies are fitted well by an exponential law. Twelve of these galaxies are early-types, and the rest are late-types. We produce a master catalog of the M106 Group galaxies by combining these new galaxies with 30 known galaxies. The faint-end of the luminosity function of these galaxies is fitted by a power law with an index ${\alpha}=-1.22{\pm}0.02$. This slope is much flatter than the value predicted by the ${\Lambda}CDM$ models, but is similar to the values for other galaxy groups. The spatial distribution of the dwarf galaxies in the M106 group is quite different from that of the bright members of the group, requiring a further study.

• Publications of The Korean Astronomical Society
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• v.32 no.1
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• pp.193-195
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• 2017

We demonstrate the luminosity dependence of the covering factor (CF) of active galactic nuclei (AGNs), based on AKARI mid-infrared all-sky survey catalog. Combining the AKARI with Sloan Digital Sky Survey (SDSS) spectroscopic data, we selected 243 galaxies at $9{\mu}m$ and 255 galaxies at $18{\mu}m$. We then identified 64 AGNs at $9{\mu}m$ and 105 AGNs at $18{\mu}m$ by their optical emission lines. Following that, we estimated the CF as the fraction of type 2 AGN in all AGNs. We found that the CF decreased with increasing $18{\mu}m$ luminosity, regardless of the choice of type 2 AGN classification criteria.

• Journal of the Korean Society for Library and Information Science
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• v.40 no.2
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• pp.315-332
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• 2006

In the 21st knowledge society, libraries should consider OPAC redesign and functional performance improvement by using new web related technology. This paper studied and analyzed case studies of Web 2.0. Library 2.0, domestic and international web portals and libraries. Based on the research, this study implemented Open API and RSS reader and proposes its utilization plan as a next generation OPAC 2.0 service model which can improve OPAC search results and search service.

• The Transactions of the Korea Information Processing Society
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• v.5 no.1
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• pp.1-11
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• 1998

This paper describes design and implementation of the system that is used to efficiently retrieve music information at a digital music library. Unlike typical music information retrieval systems, this system allows the user to sing a part of the melody through the microphone which he/she wants to find rather than using title, composer or the subject catalog to search. The system then recognizes the musical notes information through the signal processing of the sounds of the entered melody, and the intervals contour is created based on this information and used as a search pattern. By running the proposed notes string search algorithm that uses the musical notes information processed with the user input, and it produces the approximate search results. Therefore, users are able to retrieve and appreciate the music whenever he/she can sing any portion of the desired music.

• Nuclear Engineering and Technology
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• v.51 no.5
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• pp.1297-1306
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• 2019

Probabilistic safety assessments (PSA) have been used for several decades to visualize the risk level of commercial nuclear power plants (NPPs). Since the role of a human reliability analysis (HRA) is to provide human error probabilities for safety critical tasks to support PSA, PSA quality is strongly affected by HRA quality. Therefore, it is important to understand the underlying limitations or problems of HRA techniques. For this reason, this study conducted a survey among 14 subject matter experts who represent the HRA community of domestic Korean NPPs. As a result, five significant HRA issues were identified: (1) providing a technical basis for the K-HRA (Korean HRA) method, and developing dedicated HRA methods applicable to (2) diverse external events to support Level 1 PSA, (3) digital environments, (4) mobile equipment, and (5) severe accident management guideline tasks to support Level 2 PSA. In addition, an HRA method to support multi-unit PSA was emphasized because it plays an important role in the evaluation of site risk, which is one of the hottest current issues. It is believed that creating such a catalog of prioritized issues will be a good indication of research direction to improve HRA and therefore PSA quality.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.1
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• pp.79.3-79.3
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• 2019

Observational evidence for intrinsic galaxy alignments in isolated spiral pairs is presented. From the catalog of the galaxy groups identified by Tempel et al. in the flux-limited galaxy sample of the Sloan Digital Sky Survey Data Release 10, we select those groups consisting only of two spiral galaxies as isolated spiral pairs and investigate if and how strongly the spin axes of their two spiral members are aligned with each other. We detect a clear signal of intrinsic spin alignment in isolated spiral pairs, which leads to the rejection of the null hypothesis at the 99.9999% confidence level via the Rayleigh test. It is also found that those isolated pairs comprising two early-type spiral galaxies exhibit the strongest signal of intrinsic spin alignment and that the strength of the alignment signal depends on the angular separation distance as well as on the luminosity ratio of the member galaxies. Using the dark matter halos consisting of only two subhalos resolved in the EAGLE hydrodynamic simulations, we repeat the same analysis but fail to find any alignment tendency between the spin angular momentum vectors of the stellar components of the subhalos, which is in tension with the observational result. Several possible sources of this apparent inconsistency between the observational and the numerical results are discussed.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.2
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• pp.59.2-59.2
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• 2018

We introduce a new project of constructing a large spectro-photometric samples of metal-poor (i.e. [Fe/H] < -1.0) subdwarfs in the Galactic halo. The sample is collected from a compilation of the stellar objects that are cross-identified both in the Sloan Digital Sky Survey (SDSS) and recently published data from GAIA mission. The color range of the selected stars covers 0.0 < (g-r) < 2.0; thus the spectral types of our sample span from early F- through late K-type stars on the metal-poor main sequence (i.e. the local subdwarf sequence). We scrutinized the physical, chemical, and kinematical properties of our samples using their SDSS medium-resolution (R ~ 2000) spectra, combined with accurately measured proper motions from GAIA satellite. Our study will provide useful information on the global trend in the various properties (e.g. abundance pattern as a function of the galactocentric distance; rotational velocity vs [Fe/H] ${\cdots}$ etc) of the metal-poor subdwarf populations in the Galactic halo, which is ultimately important to better understand metal-poor stellar evolutionary models and chemical evolution of the Milky Way halo in the early phase of its formation. Further our comprehensive catalog of the Galactic field halo subdwarfs collected in this study will serve a solid groundwork for future follow-up high resolution spectroscopic observations on many interesting individual targets.