• The Bulletin of The Korean Astronomical Society
• /
• v.35 no.2
• /
• pp.28.2-28.2
• /
• 2010

We investigate star clusters in the Stephan's Quintet using Wide Field Camera 3 of the Hubble Space Telescope and three filters (F438W, F606W, F814W). Stephan's Quintet located at ~ 85 Mpc, so most star clusters are seen like point source even in HST image. We perform the Point Spread Funtion fitting photometry to find star clusters. Then we have selected 749 star cluster candidates by visual inspection. Usinng simple steallr population models (Bruzual & Charlot, 2003), we estimate ages of these star clusters. Many young star clusters found in tidal features of NGC 7318 and NGC 7319. Also star clusters in the shocked region of NGC7318 have younger age than those in NGC 7319 tidal tail. These result implies interaction which distrupt NGC 7319 first, and collision between NGC 7318 A/B occurred. In contrast, old star clusters are mainly located in NGC 7317 and in the center of other galaxies. Implications of these result will be discussed.

• Journal of Korea Multimedia Society
• /
• v.6 no.3
• /
• pp.556-564
• /
• 2003

A Star and Pancake graph also have such a good property of a hypercube and have a low network cost than the hypercube. A Macro-star graph which has the star graph as a basic module has the node symmetry, the maximum fault tolerance, and the hierarchical decomposition property. And, it is an interconnection network which improves the network cost against the Star graph. In this paper, we propose a method to embed between Star graph, Pancake graph, and Macro-star graph using the edge definition of graphs. We prove that the Star graph $S_n$ can be embedded into Pancake graph $P_n$ with dilation 4, and Macro-star graph MS(2,n) can be embedded into Pancake graph $P_{2n＋1}$ with dilation 4. Also, we have a result that the embedding cost, a Pancake graph can be embedded into Star and Macro-star graph, is O(n).

• Asia Marketing Journal
• /
• v.12 no.1
• /
• pp.51-79
• /
• 2010

This study is based on recent advances in celebrity traits and self-determination researches to address how consumers develop the strong attachment to a "star brand," and the effect of consumer's attachment to star brand on evaluation of product brand sponsored by the star. We use the consumers' need satisfaction and star traits as major causal factors that influence consumer's attachment to a star brand. Specifically this article uses autonomy need, relatedness need, competence need as the dimensions of need satisfaction and expertness, trustworthiness, likeability, and similarity as the key star traits. The purpose of this study is to investigate the influence of these factors on the consumer's attachment to star brand and how consumer's evaluation of product brand sponsored by star is moderated by the fitness level of between the image of star brand and the image of sponsored product brand. To collect the data, survey was taken in a University located in Incheon. Collected data are analysed using SPSS 15.0 and AMOS 7.0. The results show that when the star brand is perceived as more trustworthy and likeable, and satisfies autonomy need and relatedness need, the consumer is more likely to become strongly attached to him or her. The hypothesis that consumer's attachment to star brand will have the positive influence on the evaluation of product brand sponsored by star is supported. And hypothesis that consumer's attitude to a sponsored product brand is moderated by the fitness level of between the image of star brand and the image of sponsored product brand is also supported. The empirical results imply that star brand to which consumers are attached may have the significant positive impact on the consumers' evaluation process of endorsed product brand and purchase behavior, and that marketers should consider need dimensions which target consumers want to satisfy and the fitness level of between the image of star brand being considered as endorser and the image of product brand.

• Journal of Astronomy and Space Sciences
• /
• v.22 no.3
• /
• pp.273-282
• /
• 2005

A star sensor daytime observation model is developed in order to test the performance of the star sensor useful for daylight application. The centroid errors of the star sensor in the day time application are computed by using the model. The standard atmospheric model (LOWTRAN7) is utilized to calculate the physical quantities of the daylight atmospheric environments where the star sensor is immersed. This observation model takes the separation angles between the sun and star, the centroid algorithm and the various system specifications of the star sensor into the account. The developed star sensor model will provide more realistic measurement errors in estimating the performance of the attitude determination from the vector observations.

• Journal of Astronomy and Space Sciences
• /
• v.16 no.2
• /
• pp.273-284
• /
• 1999

In order to develop star trackers for a satellite in our country we studies selection procedure of optical parameters. For logical selection of the optical parameters, we simulated the entire processes in which star lights imaged on a CCD sensor were read into and processed in an associated electronics. The simulation resulted in relations between star's magnitude and achievable pointing accuracy, from which we derived optimal optical parameters to satisfy a required pointing accuracy of a star tracker. The selected optical parameters were used in an optical system design of a star tracker with a pointing accuracy of 10 arcsec.

• The Bulletin of The Korean Astronomical Society
• /
• v.39 no.1
• /
• pp.39.2-39.2
• /
• 2014

We present a photometric study of star clusters in the nuclear starburst region of NGC 253 using gVI, YJ, and H band images in the Hubble Space Telescope archive. We find about one thousand star clusters in about 200"x200" field by visual inspection with I<21. We also find about ten thousand star clusters in the same field by automated classification method with magnitude range of 21< I $$\leq_-$$ 24. Ages and masses of star clusters are estimated using spectral energy distribution fitting method. Age distribution of star cluster shows two distinguished young populations with peak ages at 3.5 Myr and 18 Myr. Old populations (>100 Myr) are exist, but their number is small. About thirty young massive star clusters (<10 Myr, ) are found in nuclear region of NGC 253 which are regarded as a result of the recent starburst. Mass function of young star clusters in NGC 253 is somewhat different with those of star clusters in other galaxies. This result suggests that initial cluster mass functions (ICMFs) for star clusters are not universial. Especially ICMF in starburst galaxies may be distinguishable compared with those in normal spiral galaxies. We discuss the implications of these results.

• Proceedings of the KIEE Conference
• /
• 1992.07b
• /
• pp.784-788
• /
• 1992

GSC ( Gold Star Cable Co, Ltd ) have developed Testing Equipment for high Voltaga Cable. The design concept and manufacture and Testing procedure are introduced in this paper.

• Journal of the Korean Mathematical Society
• /
• v.46 no.6
• /
• pp.1179-1192
• /
• 2009

In this note we give a new generalization of the notions of $Pr{\ddot{U}}fer$ domain and PvMD which uses quasi semistar invertibility, the "quasi P$\star$MD", and compare them with the P$\star$MD. We show in particular that the problem of when a quasi P$\star$MD is a P$\star$MD is strictly related to the problem of the descent to subrings of the P$\star$MD property and we give necessary and sufficient conditions.

• Proceedings of the IEEK Conference
• /
• 1998.10a
• /
• pp.467-470
• /
• 1998

In this paper, we propose a matrix star graph which improves the network cost of the well-known star grah as an interconnection network. We analyze its characteristics in terms of the network parameters, such as degree, scalability, routing, and diameter. The proposed matrix star graph MS2,n has the half degrees of a star graph S2n with the same number of nodes and is an interconnection network with the properties of node symmetry, maximum fault tolerance, and recursive structure. In network cost, a matrix star graph MS2,n and a star graph S2n are about 3.5n2 and 6n2 respectively which means that the former has a better value by a certain constant than the latter has.

• The Bulletin of The Korean Astronomical Society
• /
• v.41 no.2
• /
• pp.29.4-29.4
• /
• 2016

The relations between star formation and properties of molecular clouds are studied based on a sample of star forming regions in the Galactic Plane. Sources were selected by having radio recombination lines to provide identification of associated molecular clouds and dense clumps. Radio continuum and mid-infrared emission were used to determine star formation rates, while 13CO and submillimeter dust continuum emission were used to obtain masses of molecular and dense gas, respectively. We test whether total molecular gas or dense gas provides the best predictor of star formation rate. We also test two specific theoretical models, one relying on the molecular mass divided by the free-fall time, the other using the free-fall time divided by the crossing time. Neither is supported by the data. The data are also compared to those from nearby star forming regions and extragalactic data. The star formation "efficiency," defined as star formation rate divided by mass, spreads over a large range when the mass refers to molecular gas; the standard deviation of the log of the efficiency decreases by a factor of three when the mass of relatively dense molecular gas is used rather than the mass of all the molecular gas.