• The Bulletin of The Korean Astronomical Society
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• v.34 no.1
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• pp.191.1-191.1
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• 2009

• Culinary science and hospitality research
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• v.20 no.5
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• pp.1-10
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• 2014

The employment rate has become the standard for university values. This raises the need to investigate the antecedents of university students' career exploration. Focused on the hospitality majored students, this study aims to investigate both individual and relational factors that influence their career exploration behaviors. Differentiation of self has been chosen as the individual and the relational antecedents based on Bowen's theory. It was investigated whether each dimension(I-position, emotional reactivity, fusion with others, and emotional cutoff) explains the amount of self-exploration and the amount of environmental exploration. The university students majoring in hospitality were surveyed and a total of 269 cases out of 300 cases were analyzed employing descriptive statistics and multi-variate analysis of variance, and structural equation modeling(SEM). The study found that I-position positively influenced self-exploration and environmental exploration. Emotional reactivity made an influence on environmental exploration, while it failed to explain self-exploration. Fusion with others and emotional cutoff also significantly influenced environmental exploration, however, it didn't make any significant influence on self-exploration. This study implies that the college of hospitality majors needs to understand that differentiation of self forms through family relationship and needs to provide the students the programs of how to understand themselves and what to do for their career exploration.

• The Bulletin of The Korean Astronomical Society
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• v.45 no.1
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• pp.34.3-34.3
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• 2020

Faint z ~ 5 quasars with M1450 ~ -23 mag are known to be the potentially important contributors to the ultraviolet ionizing background in the post-reionization era. However, their number density has not been well determined, making it difficult to assess their role in the early ionization of the intergalactic medium (IGM). In this work, we present the updated results of our z ~ 5 quasar survey using the Infrared Medium-deep Survey (IMS), a near-infrared imaging survey covering an area of 85 square degrees. From our spectroscopic observations with the Gemini Multi-Object Spectrograph (GMOS) on the Gemini-South 8 m Telescope, we discovered eight new quasars at z ~ 5 with -26.1 ≤ M1450 ≤ -23.3. Combining our IMS faint quasars with the brighter Sloan Digital Sky Survey (SDSS) quasars, we derive, for the first time, the z ~ 5 quasar luminosity function (QLF) without any fixed parameters down to the magnitude limit of M1450 = -23 mag. We find that the faint-end slope of the QLF is very flat (-1.2) with a characteristic luminosity of -25.7 mag. The number density of z ~ 5 quasars from the QLF gives lower ionizing emissivity and ionizing photon density than those in previous works. These results imply that quasars are responsible for only 10-20% of the photons required to completely ionize the IGM at z ~ 5, disfavoring the idea that quasars alone could have ionized the IGM at z ~ 5.

• Geophysics and Geophysical Exploration
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• v.5 no.1
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• pp.64-67
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• 2002

• The Bulletin of The Korean Astronomical Society
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• v.43 no.2
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• pp.36.2-36.2
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• 2018

Cosmic reionization era in the early universe was playing a leading part on making the present universe we know. However, we have not been able to reveal the main contributor to the cosmic reionization to date. Faint quasars have been mentioned as the alternative due to the uncertainty of the faint end slope of the quasars luminosity function. With the availability of the deep (~25mag) images from Subaru Hyper Suprime-Cam (HSC) Strategic Program survey, we have tried to find more quasar with low luminosity in the ELAIS-N1 field. Faint quasar candidates were selected from several multi-band color cut criteria based on the track of the simulated quasar at z ~ 5. The Infrared Medium-deep Survey (IMS) and The UKIRT Infrared Deep Sky Survey (UKIDSS) - Deep Extragalactic Survey (DXS) provide J band information which is used to cover the relatively long wavelength range of quasar spectra. To search the reliable candidates with possible Lyman break, medium-band observation was performed by the SED camera for QUasars in EArly uNiverse(SQUEAN) in the McDonald observatory and Seoul National University 4k Camera(SNUCAM) in the Maidanak observatory. Photometric redshifts of the observed candidates were estimated from chi-square minimization. Also, we predicted the importance of the faint quasar to the cosmic reionization from the expected number density of the faint quasar.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.5B
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• pp.304-309
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• 2005

In this paper, we propose a localized Adaptive QoS Routing using TD method and evaluate performance of various exploration methods when path is selected. Expecially, through extensive simulation, the proposed routing algorithm and exploration method using Exploration Bonus are shown to be effective in significantly reducing the overall blocking probability, when compared to the other path selection method(exploration method), because the proposed exploration method is more adaptive to network environments than others when path is selected.

• Korean Journal of Child Studies
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• v.21 no.2
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• pp.171-188
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• 2000

The level of representation, exploration and artistry by age and sex was examined in twenty children in each of 4-, 5-, and 6-year old groups attending an early education facility in Pundang City, Kyong'gi Province. Evaluation was by the scoring system used in the Project Spetrum(Krechevsky, 1994) with children's drawings of an animal, person, imaginary animal and 3D work with clay. Data were analyzed by 2-way ANOVA and Duncan test. The level of representation was lower than exploration and artistry in the 4-year-old groups. Level of artistry was lower than representation and exploration in the 5-and 6-year-old groups. The older children and girls showed higher scores than the younger children and boys in representation and exploration. There were differences between 4-and 5-year old children in artistry development.

• Journal of The Korean Astronomical Society
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• v.52 no.1
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• pp.11-21
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• 2019

Intensive Monitoring Survey of Nearby Galaxies (IMSNG) is a high cadence observation program monitoring nearby galaxies with high probabilities of hosting supernovae (SNe). IMSNG aims to constrain the SN explosion mechanism by inferring sizes of SN progenitor systems through the detection of the shock-heated emission that lasts less than a few days after the SN explosion. To catch the signal, IMSNG utilizes a network of 0.5-m to 1-m class telescopes around the world and monitors the images of 60 nearby galaxies at distances D < 50 Mpc to a cadence as short as a few hours. The target galaxies are bright in near-ultraviolet (NUV) with $M_{NUV}$ < -18.4 AB mag and have high probabilities of hosting SNe ($0.06SN\;yr^{-1}$ per galaxy). With this strategy, we expect to detect the early light curves of 3.4 SNe per year to a depth of R ~ 19.5 mag, enabling us to detect the shock-heated emission from a progenitor star with a radius as small as $0.1R_{\odot}$. The accumulated data will be also useful for studying faint features around the target galaxies and other science projects. So far, 18 SNe have occurred in our target fields (16 in IMSNG galaxies) over 5 years, confirming our SN rate estimate of $0.06SN\;yr^{-1}$ per galaxy.

• Journal of the Korean Geophysical Society
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• v.5 no.3
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• pp.247-268
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• 2002

The various geophysical exploration techniques, which are currently employed in Korea, are investigated in terms of the survey specifications used in the geotechnical and engineeringl markets in Korea, Japan, and USA.

• Journal of The Korean Astronomical Society
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• v.43 no.3
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• pp.75-93
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• 2010

We present the characteristics of the Seoul National University 4k Camera (SNUCAM) and report its performance on the 1.5m telescope at the Maidanak observatory in Uzbekistan. SNUCAM is a CCD camera with a pixel scale of 0.266" in $4096{\times}4096$ format, covering $18.1'{\times}18.1'$ field of view on the 1.5m. The camera is currently equipped with Bessell UBVRI, $H{\alpha}$, SDSS ugriz, and Y-band filters, allowing us to carry out a variety of scientific programs ranging from exoplanet studies to survey of quasars at high redshift. We examine properties of SNUCAM such as the bias level and its temporal variation, the dark current, the readout noise, the gain, the linearity, the fringe patterns, the amplifier bias, and the bad pixels. From our observations, we also constructed the master fringe frames in I-, z-, and Y-band. We outline some of the current scientific programs being carried out with SNUCAM, and demonstrate that SNUCAM on the 1.5m can deliver excellent images that reach to the $5-{\sigma}$ detection limits of R~25.5 mag and z~22.7 mag in 1 hour total integration.