• 천문학회보
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• 제36권2호
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• pp.76.2-76.2
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• 2011

It is widely accepted that the SED of a galaxy relates to its morphology. In addition, the SED of the galaxy is closely connected to its star formation history, and its morphological properties are affected by the merger history, interactions with its environment, and the gravitational instability of its dynamical system. Thus, it is likely that star formation history correlates to the elements that determine morphological properties. Among the elements, this study investigates how much the merger histories of galaxies influence their star formation histories. By using simple merger trees and semi-analytic models, which disregard feedback processes to exclusively identify merger effects on star formation histories, we examine the relation between various merger histories and SEDs of galaxies. From the results, we discuss whether the SED of a galaxy can represent and constrain its merger history.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 정기총회 및 창립40주년기념 학술대회 학회본부
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• pp.408-411
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• 1987

We have designed the power supply of an 120W $CO_2$ Laser for non-metal material processings. High voltage is automatically controlled by means of thyristor triggered phase control. Pulse and C.W. mode are selectively generated by means of discharge current control. It is possible to interface this system with other Numerical Controller. Also, safety interlock circuit is incorporated in this system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 전기.전자공학 학술대회 논문집
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• pp.209-212
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• 1988

This paper presents a new uniform sampling method for two-dimensional contour. The proposed method improves the uniformity of contour sampling in terms of the interpolation of the corner points extracted from chain codes. The performance of the proposed method is analyzed through the length estimation and shape recognition of two-dimensional contour. The experimental results show the significant improvement over the conventional method.

• 국제초고층학회논문집
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• 제2권4호
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• pp.285-291
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• 2013

This paper proposes a framework for understanding the energy consumption differences between tall and low-rise buildings. Energy usage data from 706 office buildings in New York illustrates expected correlations from the framework. Notable correlations include: taller buildings tend to use more energy until a plateau at 30~39 floors; tall buildings in Manhattan use 20% more energy than low-rise buildings in Manhattan, while tall buildings outside Manhattan use 4% more energy than low-rise buildings outside Manhattan. Additional correlations are discussed, among which is the trend that the Energy Star program in New York City assigns higher ratings to tall buildings with higher EUIs than low-rise buildings with the same EUI. Since Energy Star is based on regressions of existing buildings, the Energy Star ratings suggest taller buildings have higher EUIs than shorter buildings, which is confirmed by the New York City energy benchmarking data.

• Journal of Astronomy and Space Sciences
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• 제9권1호
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• pp.111-119
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• 1992

The IUE archival spectra of VV Cephei were collected to investigate the eclipse nature in the ultraviolet. The temperature of the B star has been determined, as approximately 30000K, based on the flux distributions during egress. Light curves of VV Cephei were reduced from the spectrophotometry of the IUE archival spectra. Three light curves at the center wavelengths of 2350 ${\AA}$, 2550 ${\AA}$ and 2850 ${\AA}$ have been analyzed by the modified Wilson and Devinney light curve program. The radii of the B star and M star were deduced to 0.05 and 0.22 of unit separation, respectively. The UV light curves show an evidence that the light was attenuated by the highly opaque atmosphere of the M star.

• 한국지구과학회지
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• 제35권5호
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• pp.362-374
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• 2014

This study investigated the initial mass function (IMF) and star formation history of high-mass stars in the Small Magellanic Cloud (SMC) using a population synthesis technique. We used the photometric survey catalog of Lee (2013) as the observable quantities and compare them with those of synthetic populations based on Bayesian inference. For the IMF slope (${\Gamma}$) range of -1.1 to -3.5 with steps of 0.1, five types of star formation models were tested: 1) continuous; 2) single burst at 10 Myr; 3) single burst at 60 Myr; 4) double bursts at those epochs; and 5) a complex hybrid model. In this study, a total of 125 models were tested. Based on the model calculations, it was found that the continuous model could simulate the high-mass stars of the SMC and that its IMF slope was -1.6 which is slightly steeper than Salpeter's IMF, i.e., ${\Gamma}=-1.35$.

• 천문학회지
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• 제37권3호
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• pp.119-129
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• 2004

A new method has been developed to solve the star cluster membership problem. It is based on synthetic photometry employing the Black Body concept as stellar radiation simulator. Synthetic color-magnitude diagram is constructed showing the main sequence band and the positions of binary star systems of combinations of various components through different photometric tracks. The method has been applied to the Hyades. The cluster membership problem has been re-appraised for the cluster (both single and binary) stars. For the binary members, the components' spectral types have been derived by the method. The results obtained agree very well with those found in literature, The method is simpler than the others and can be developed to undertake other cases as multiple star systems.

• 천문학회보
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• 제39권1호
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• pp.44.1-44.1
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• 2014

Blue Compact Dwarf galaxies (BCDs) are systems that recently have experienced the burst of star formation. As one of the causes for active star formation in BCDs, tidal interaction (fly-by or merger) has been suggested. A pair of BCDs, ESO 435-IG20 and ESO 435-IG16 are separated by only ~80 kpc in projection at a similar redshift (at a ~9 Mpc distance), and hence suspected to be a good example of such case. Intergalactic atomic hydrogen gas found in HIPASS survey is also suggestive of this hypothesis. In this study, we probe the HI morphology and kinematics of this BCD pair using ATCA HI data to study detailed interaction history. We investigate various star formation tracers of the pair to study how responsible tidal interaction is for triggering star formation in these galaxies.

• 한국통신학회논문지
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• 제21권9호
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• pp.2526-2532
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• 1996

In this paper, the efficient algorithm for design of waveguide grating router(WGR) composed of star couplers is proposed. It is well demostrated that a star coupler design can be easily adjusted to the optimumstate using the proposed design method, which analyzes relations between various parameters. This method enables designers to estimate the spectral properties of waveguide grating router at the initial design level of the star coupler. A 5*5 WGR with 2.75nm(343GHz) channel spacing is designed using the proposed scheme. The BPM(Beam Propagation Method) simulation results show that the channel spacing of the WGR agrees very well with the design, the excess loss is smaller than 2.5dB, and the crosstalk is less than -21dB.

• 천문학회보
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• 제36권1호
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• pp.60.1-60.1
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• 2011

We present preliminary results of a statistical study on star formation history of infrared luminous galaxies selected from a IRAS-SDSS matched sample. We derive their star formation histories by comparing observed optical spectra and stellar population synthetic model templates. We find that young population fraction (<500 Myr) increases with infrared luminosity, while AGN-host (based on optical line ratios) galaxies show an enhancement of star formation at intermediate age (around 1 Gyr) compared with starburst galaxies. These results support that infrared luminosity is dominated by starburst activity and that there is an evolutionary connection from starburst to AGN.