• Journal of Astronomy and Space Sciences
• /
• v.33 no.4
• /
• pp.257-264
• /
• 2016

A planet revolving around binary star system is a familiar system. Studies of these systems are important because they provide precise knowledge of planet formation and orbit evolution. In this study, a method to determine the evolution of an exoplanet revolving around a binary star system using different rates of stellar mass loss will be introduced. Using a hierarchical triple body system, in which the outer body can be moved with the center of mass of the inner binary star as a two-body problem, the long period evolution of the exoplanet orbit is determined depending on a Hamiltonian formulation. The model is simulated by numerical integrations of the Hamiltonian equations for the system over a long time. As a conclusion, the behavior of the planet orbital elements is quite affected by the rate of the mass loss from the accompanying binary star.

• Journal of the Korean Mathematical Society
• /
• v.44 no.2
• /
• pp.297-306
• /
• 2007

In this paper, we present a new kind of duality between intersection bodies and projection bodies. Furthermore, we establish some counterparts of dual Brunn-Minkowski inequalities for intersection bodies.

• Proceedings of the KIEE Conference
• /
• 1993.07b
• /
• pp.1168-1170
• /
• 1993

EHV underground transmission cable characterized by low loss and bulk capacity should have high reliability to be protected fully from external damages, not to speak of its quality. In 345kV underground transmission lines of our country, the usage of frie protection trough is standardized. Fire protection trough consists of combination of trough body, spacer, shutting board, fastener, and etc. and it is required to have a high level of fire-retardant characteristics and mechanical strength. Since 1992, we, GoldStar Cable, with collaboration of Lucky, have participated in the development of fire protect ion trough and completed the type test of manufacturing site and will be supposed to go into mass product within 1993.

• The Bulletin of The Korean Astronomical Society
• /
• v.44 no.1
• /
• pp.40.1-40.1
• /
• 2019

We utilize times since infall of cluster galaxies obtained from Yonsei Zoom-in Cluster Simulation (YZiCS), the cosmological hydrodynamic N-body simulations, and star formation rates from the SDSS data release 10 to study how quickly late-type galaxies are quenched in the cluster environments. In particular, we confirm that the distributions of both simulated and observed galaxies in phase-space diagrams are comparable and that each location of phase-space can provide the information of times since infall and star formation rates of cluster galaxies. Then, by limiting the location of phase-space of simulated and observed galaxies, we associate their star formation rates at z ~ 0.08 with times since infall using an abundance matching technique that employs the 10 quantiles of each probability distribution. Using a flexible quenching model covering different quenching scenarios, we find the star formation history of satellite galaxies that best reproduces the obtained relationship between time since infall and star formation rate at z ~ 0.08. Based on the derived star formation history, we constrain the quenching timescale (2 - 7 Gyr) with a clear stellar mass trend and confirm that the refined model is consistent with the "delayed-then-rapid" quenching scenario: the constant delayed phase as ~ 2.3 Gyr and the quenching efficiencies (i.e., e-folding timescale) outside and inside clusters as ~ 2 - 4 Gyr (${\propto}M_*^{-1}$) and 0.5 - 1.5 Gyr (${\propto}M_*^{-2}$), Finally, we suggest: (i) ram-pressure is the main driver of quenching of satellite galaxies for the local Universe, (ii) the quenching trend on stellar mass at z > 0.5 indicates other quenching mechanisms as the main driver.

• Korean Journal of Optics and Photonics
• /
• v.24 no.1
• /
• pp.17-22
• /
• 2013

High performance plastic optical fiber (POF) $N{\times}N$ star couplers are implemented based on fusing and combining technology. A set of cladding-removed POFs are fused into a solid body by heating and pressing them together to form the transition region between the input and output sides. The operation principle of the proposed star coupler is explained based on ray optics. To demonstrate the performance of the device, $2{\times}2$, $4{\times}4$ and $6{\times}6$ type POF couplers were fabricated and characterized. Performances of the POF star couplers were evaluated in terms of the flatness of the coupling ratios and excess losses.

• Journal of The Korean Astronomical Society
• /
• v.37 no.3
• /
• pp.119-129
• /
• 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.

• 한국지구과학회:학술대회논문집
• /
• 2010.04a
• /
• pp.118-119
• /
• 2010

star formation is one of the hottest areas in astromy and increasing evidence is showing that star formation is actually a highly dynamic precess driven and strongly influenced by turbulent dynamics of molecular clouds. despite significant progress ir observation in process of star formation, earliest stage of star formation remains imcomplete. so, computer simulations are essential tool since the complex dynamics of star formation. We have performed simulation about the process of low mass star formation using the SPH simulation. we use the dragon-code, the most advanced star formation N-body Smoothed Particle Hydrodynamics (SPH) codes. We present how change the internal properties and how should evolve, while changing the values for Mass turbulence, central density and so on. ( mass range of values is 0.1 < M < $5\;M{\odot}$) based on this results, we discussed their circumstellar, characteristics they were borned and how they will evove while the Birth of low mass stars from interstellar cloud.

• The Research Journal of the Costume Culture
• /
• v.17 no.2
• /
• pp.296-308
• /
• 2009

The purpose of this study is to comprehend the contemporary sports star fashion and to contemplate aesthetic characteristics of sports star fashion, thereby to establish the styles of sports star fashion. For such purposes, this study first examines aesthetic characteristics of sports fashion and star fashion based on previous studies, in order to analyze aesthetic characteristics of sports star fashion, and conducts a case study by analyzing photographic materials of fashion styles of well-known male sports stars such as the English soccer player David Beckham and American golf player Tiger Woods. The result of this study is as follows: the aesthetic characteristics of the contemporary sports star fashion are virility, functionality, sensuality and deconstruction. (1) Virility emphasizes manly features by displaying trained and disciplined body. (2) Functionality is expressed through structural simplicity and temperance of decoration. High-tech textiles and fibers are favored in order to fit in comfortable bodily movement for the heavy exercises. (3) Sensuality, as an expression of indulgence of sexual pleasure, is expressed through bodily exposure. Lastly, (4) deconstruction, which means destroying existed boundaries of cultural categories, is shown as co-existence of design elements from different times and places, stereotypes and sensibilities. Virility and functionality are prominent characteristics expressed in sports uniforms and training costumes. Sensuality and deconstruction are shown in daily fashion and formal dress outside the sports field.

• The Bulletin of The Korean Astronomical Society
• /
• v.37 no.1
• /
• pp.40.1-40.1
• /
• 2012

In the hierarchical universe, galaxy merger is predicted to be frequent, and thus it is an important element for understanding galaxy evolution. In particular, star formation is greatly enhanced during the merger. The aim of this study is to understand the position and rate change of star formation caused by equal-mass edge-on mergers. We use the GADGET2- N-body/SPH code, and fully consider gas cooling, star formation, and supernova feedback. We show the star formation rate (SFR), and the magnitude and color evolution of the merger remnants for 18 different configurations varying orbit elements and inclinations of host galaxies against orbit planes. Then we construct the mock images of the remnants and investigate on how equal-mass galaxy merger affects the SFR and color/magnitude evolution while considering dust reddening. We conclude that over 90% mass of SF in equal-mass merger is in the central region. SF in tidal feature involves a small fraction of new stars and thus is difficult to detect unless deep imaging is performed. Around 55 ${\pm}$ 5 percent of gas turns into stars until the final coalescence which typically corresponds to 0.8, 1.2, and 2.5 Gyr for direct, parabolic, and elliptical orbit, respectively. This result is roughly consistent with Cox et al. 2000. We plan to implement this result into semi-analytic model of galaxy formation. Caveats and future work on merging conditions are discussed.

• Journal of the Korean Society of Costume
• /
• v.61 no.6
• /
• pp.146-160
• /
• 2011

The purpose of this study is to examine the aesthetic view towards exposure in the Korean society through the means of analyzing the characteristics of exposure and figuring out the implications expressed in the red carpet fashion of Korean female movie stars. The concept of exposure in fashion was reviewed through previous studies and related publications. The pictures of actresses wearing red carpet evening gowns in Korea's major film festival were collected and analyzed. The results indicated that the meaning of exposure expressed in the red carpet fashion of Korean female movie stars are as follows: First, this leads the trend reflecting the contemporary aesthetic view of exposure as an effective way to show the beauty of the female body. Second, this emphasizes the femininity and expresses eroticism by exposing certain body parts which symbolize the female gender. Third, this shows the narcissistic self conspicuousness as well as the self confidence and self satisfaction. Forth, this displays the playfulness through exposing the body in a unique way. Lastly, the way and level of exposure can be used to maintain or change the public's view upon the celebrity.