• The Bulletin of The Korean Astronomical Society
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• 제40권2호
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• pp.30.2-30.2
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• 2015

Abell 2744 is a giant merging cluster, called the Pandora's Cluster, at the redshift of z=0.308 (corresponding to a distance of 1270 Mpc). Taking the advantage of the deep high resolution images in the Hubble Frontier Field program, we study the properties of compact stellar systems including globular clusters and ultracompact dwarfs (UCDs) as well as dwarf galaxies in this cluster. We find a rich population of globular clusters and UCDs in Abell 2744. The spatial distribution of these objects is consistent with the mass map derived from lensing analysis, while showing a significant offset from the X-ray map of hot gas. The faint end of the luminosity function of the galaxies in the red sequence is fit by a flat slope, showing no faint upturn. We discuss these finding in relation with the origin of UCDs, formation of red sequence dwarf galaxies, and formation of the Pandora's cluster.

• The Bulletin of The Korean Astronomical Society
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• 제42권2호
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• pp.41.1-41.1
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• 2017

We present weak-lensing analysis of the merging galaxy cluster Abell 115 at z=0.197 based on Subaru i and V band images. As merging clusters often show, Abell 115's merging signatures include radio relics, double X-ray peaks, and large offsets between the cluster member galaxies and the X-ray distributions. A weak-lensing study provides underlying dark matter distribution, the key information to determine the complex merging scenario of the cluster. In this work, we present 2D mass reconstruction of the cluster, which reveals two distinct mass peaks consistent with galaxy distributions. We measure the first weak-lensing mass of each subcluster. Our weak-lensing total mass estimate is a few factors lower than the published dynamical mass obtained from velocity dispersion. This large mass discrepancy may be attributed to a significant departure from dynamical equilibrium. We also re-analyze the archival chandra data and find that the result is consistent with weak-lensing mass.

• The Bulletin of The Korean Astronomical Society
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• 제35권1호
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• pp.56.2-56.2
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• 2010

M87, a cD galaxy in the Virgo cluster, has 3-10 times larger enclosed mass than the Milky Way at any given galactocentric radius. Thus the globular cluster (GC) system in M87 is expected to have undergone a more significant dynamical evolution than that of the Milky Way if it had started from the same initial mass function (MF) and radial distribution (RD) as the Milky Way. The evolution of MF and RD of the M87 GC system has been calculated using an advanced, realistic Fokker-Planck (FP) model that considers dynamical friction, disk/bulge shocks, and eccentric cluster orbits. We perform hundreds of FP calculations with different initial cluster conditions, and then search a wide parameter space for the best-fit initial GC MF and RD that evolves into the observed present-day GC MF and RD. We also find best-fit initial MFs and RDs for blue and red GC groups, separately.

• The Bulletin of The Korean Astronomical Society
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• 제35권2호
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• pp.40.1-40.1
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• 2010

We present the ultraviolet (UV) properties of early type galaxies (ETGs) in clusters. We obtained a cluster catalogue from Yoon et al.(2008) based on Sloan Digital Sky Survey(SDSS) DR5 in the redshift range of 0.05 < z <0.10. After matching sample galaxies in clusters with Galaxy Evolution Explorer (GALEX) GR5, we have classified the morphologies of ETGs by UV-optical colour distributions and investigated them in terms of the ranks in magnitude in a cluster and in clustocentric distance. It has recently been suggested theoretically that brightest cluster galaxies (BCGs) show a strong UV upturn than non-BCGs, but we find that the difference between them is not significant. Moreover, to our surprise, it appears that density (environment) does not play any significant role to the UV properties. consequent of internal galaxy processes rather than that of environmental processes.

• Journal of the Korean Society of Clothing and Textiles
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• 제15권2호
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• pp.151-162
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• 1991

The purpose of this study was to examine the point at issue unfitness and unclassification in figures for clothing construction. Comparing measurements of 3 sold figures and physical body by Suck·Go method and 19 items were selected. These items were acquired by factor analysis and cluster analysis an measurements of 200 women in twenties. The results were as follows; 1. Comparison between measurement of figures and physical body; There was not so much difference among figures, but significant difference between figures and physical body. 2. Comparison between measurement of surface area of figures and physical body; There was similar to each figure, but significant difference between figures and physical body. Mostly, figures were bigger than physical body in front parts but smaller in back parts. 3. There were 8 items selected by factor analysis; That is bust girth, waist girth, hip girth, neck base girth, posterior waist length, bust point length, chest breadth and armscye girth. 4. There were 7 clusters selected by cluster analysis.

• Management & Information Systems Review
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• 제33권2호
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• pp.171-188
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• 2014

Previous researches on technological innovation of SMEs have several limitations such as lack of study for industrial cluster system and entrepreneurship in SMEs, and ignoring role of RandD capability. So, this study suggested empirically a new model to SMEs. Major results are as follows. Firstly, system of industry and production had a significant and positive effect on entrepreneurship. Secondly, entrepreneurship had a significant and positive effect on technological innovation. Thirdly, system of science and technology had positive and significant effects on RandD capability and technological innovation. Fourthly, RandD capability had a positive and significant effect on technological innovation. Fifthly, business support system was not significantly related to entrepreneurship, RandD capability and technological innovation. Research results revealed that industrial cluster system(system of industry and production, system of science and technology), entrepreneurship and RandD capability were important for improvement of technological innovation performance in SMEs.

• Korean Journal of Adult Nursing
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• 제21권6호
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• pp.705-717
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• 2009

Purpose: The purpose of this study was to identify symptom clusters in patients with breast cancer and to investigate the associations among them with functional status and quality of life (QOL). Methods: A convenient sample of 303 patients was recruited from an oncology-specialized hospital. Results: Two distinct clusters were identified: A gastrointestinal- fatigue cluster and a pain cluster. Each cluster significantly influenced functional status and QOL. Based on these two clusters, we identified subgroups of symptom clusters using K-means cluster analysis. Three relatively distinct patient subgroups were identified in each cluster: mild, moderate, and severe group. Disease-related factors (i.e., stage, metastasis, type of surgery, current chemotherapy, and anti-hormone therapy) were associated with these subgroups of symptom clusters. There were significant differences in functional status and QOL among the three subgroups. The subgroup of patients who reported high levels of symptom clusters reported poorer functional status and QOL. Conclusion: Clinicians can anticipate that breast cancer patients with advanced stage, metastasis, and who receive mastectomy, and chemotherapy will have more intense gastrointestinal-fatigue or pain symptoms. In order to enhance functional status and QOL for patients with breast cancer, collective management for symptoms in a cluster may be beneficial.

• Journal of the Korean Home Economics Association
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• 제40권8호
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• pp.123-135
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• 2002

The purpose of this study is to examine the relationship between shopping orientation and purchasing satisfaction of apparels. To achieve the purpose, this study was carried out by means of questionnaires with female consumers aged from 20s to 50s in Daegu. The data were analysed by the frequency analysis, percentage, reliability test, factor analysis, Pearson's correlation analysis, cluster analysis, one-way ANOVA and Duncan's multiple range analysis. The statistical package for social science 9.0 for Window was used for the statistical processing of the data. The result of this study is summarized as follows. 1. To examine factors which construct female consumers' shopping orientation for apparels, a factor analysis was done, therefore, which obtained 6 factors. Also A factor analysis was done to examine the motivative factors of satisfaction with purchased apparels, 6 factors were obtained. 2. Based on the average score of shopping-orientation factors for apparels, a cluster analysis was done and it was classified into 3 clusters. There were differences in purchasing satisfaction of purchased apparels between the 3 clusters. 3. The differences in variety, shopping convenience, dignity, brand & preference, and convenient selection between the clusters were entirely p<0.001 which were very significant. There were no differences in the quality and service factors between the brand-/practicality-oriented cluster and entertainment-oriented cluster. With other factors, entertainment-oriented cluster was most satisfied than brand-/ practicality oriented cluster. But, self-reliance-oriented cluster was lowest purchasing satisfaction of apparels.

• Bulletin of the Korean Chemical Society
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• 제23권2호
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• pp.309-314
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• 2002

The ablation dynamics and cluster formation of $C_n^+$ ions ejected from 355 nm laser ablation of a graphite target in vacuum are investigated using a reflectron time-of-flight (RTOF) mass spectrometer. At low laser fluence, odd-numbered cluster ions with $3{\leq}n{\leq}15$ are predominantly produced. Increasing the laser fluence shifts the maximum size distribution towards small cluster ions, implying the fragmentation of larger clusters within the hot plume. The temporal evolution of $C_n^+$ ions was measured by varying the delay time of the ion extraction pulse with respect to the laser irradiation, providing significant information on the characteristics of the ablated plume. Above a laser fluence of $0.2J/cm^2$ , large cluster ions ($n{\geq}30$) are produced at relatively long delay times, indicating that atoms or small carbon clusters aggregate during plume propagation. The dependence of the intensity of ablated $C_n^+$ ions on delay time after laser irradiation shows that the most probable velocity of each cluster ion decreases with cluster size.

• The Bulletin of The Korean Astronomical Society
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• 제42권1호
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• pp.29.4-30
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• 2017

Korea Astronomy and Space Science Institute We present a weak-lensing study of the galaxy cluster SPT-CL J2106-5844 at z=1.132 discovered in the South Pole Telescope Sunyaev-Zel'dovich (SPT-SZ) survey. The cluster is claimed to be the most massive system at z > 1 in the SPT-SZ survey. The inferred mass ($M_{200c}=(1.27{\pm}0.21){\times}10^{15}M_{sun}$) is somewhat unusual at such a high redshift given the current ΛCDM prediction. The mass estimates, however, may be biased because the hydrostatic assumption may not hold when the universe was about 40% of the current age. In this work, we reconstruct the dark matter distribution and measure the mass of this interesting cluster using weak-lensing analysis based on the images from the Advanced Camera for Surveys and Wide Field Camera 3 on-board the Hubble Space Telescope. We find that the mass distribution of the cluster is unimodal with no significant substructures. The centroid of the dark matter agrees with both galaxy luminosity and number density distributions, as well as the hot gas centroid. We confirm that the cluster is indeed extremely massive ($M_{200c}=(1.81{\pm}0.47){\times}10^{15}M_{sun}$) supporting the previous non-lensing measurements. We also discuss the rarity of the cluster in the ΛCDM cosmology, comparing with the expected abundance of similarly massive clusters.