• The Bulletin of The Korean Astronomical Society
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• v.38 no.2
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• pp.37.1-37.1
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• 2013

We present our study of analyzing the photometric properties of the globular cluster (GC) system which resides in the extended halo of the central bright Coma cluster galaxy NGC 4874. The core of the Coma cluster of galaxies (Abell 1656) was observed with both the HST Advanced Camera for Surveys (ACS) in the F475W (g475) and F814W (I814) and Wide Field Camera 3 IR Channel (WFC3/IR) in the F160W (H160) filters. The data analysis procedure and GC candidate selection criteria are briefly described. We investigate the interesting "tilt" features in color-magnitude diagrams for this GC system and their link to the nonlinear color-metallicity relation for GCs. The NGC 4874's GC system exhibits a bimodal distribution in the optical g475-I814 color and much more than half the GCs fall in the red side at g475-I814 ~ 1.1. This bimodality is weakened in the optical-IR I814-H160 color; the quantitative analysis on the features of both color distributions using the Gaussian Mixture Modeling code proves the bimodalities are different. Both colors, thus, cannot linearly reflect the bimodality of an underlying metallicity, supporting the suggestion that observed bimodalities in extragalactic GC colors are the metallicity-to-color projection effect.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.2
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• pp.54.2-54.2
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• 2016

We present a machine learning approach to estimating stellar atmospheric parameters, effective temperature (Teff), surface gravity (log g), and metallicity ([Fe/H]) for stars observed during the course of the Sloan Digital Sky Survey (SDSS). For training a neural network, we randomly sampled the SDSS data with stellar parameters available from SEGUE Stellar Parameter Pipeline (SSPP) to cover the parameter space as wide as possible. We selected stars that are not included in the training sample as validation sample to determine the accuracy and precision of each parameter. We also divided the training and validation samples into four groups that cover signal-to-noise ratio (S/N) of 10-20, 20-30, 30-50, and over 50 to assess the effect of S/N on the parameter estimation. We find from the comparison of the network-driven parameters with the SSPP ones the range of the uncertainties of 73~123 K in Teff, 0.18~0.42 dex in log g, and 0.12~0.25 dex in [Fe/H], respectively, depending on the S/N range adopted. We conclude that these precisions are high enough to study the chemical and kinematic properties of the Galactic disk and halo stars, and we will attempt to apply this technique to Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST), which plans to obtain about 8 million stellar spectra, in order to estimate stellar parameters.

• Journal of Korea Foundry Society
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• v.34 no.2
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• pp.49-53
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• 2014

In commercial Zr-Nb-Cu-Ni-Al amorphous alloys, expensive element, Zr, was substituted to Sn which was cheaper one, and then, glass forming ability, compressive strength and hardness of them were estimated. Even though the Sn was added up to 1.5%, resulting phase was not changed to the crystalline form. It was confirmed by X-ray diffraction and thermal analyses. In the X-ray profiles, there were no peaks for crystalline phases and typical halo pattern for amorphous phase was appeared at the diffraction angle of $35^{\circ}{\sim}45^{\circ}$. Thermal analyses also showed that the Sn modified alloys were corresponded to the amorphous standards where ${\delta}T$(= Tx - Tg) and Trg(= Tg/Tm) affecting to the amorphous forming ability were more than 50K and 0.60 respectively. Compressive strengths were 1.77 GPa, 1.63 GPa, 1.65 GPa and 1.77 GPa for 0%Sn, 0.5%Sn, 1.0%Sn and 1.5%Sn respectively. Hardnesses of the Sn modified alloys were decreased from 752 Hv to 702 Hv in 1.0%Sn and recovered to 746 Hv in 1.5%Sn.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.18
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• pp.7707-7711
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• 2014

Background: Currently poster presentations offer a common visual medium for knowledge transfer by a wide range of health professionals. Our study aimed to determine the scientific importance of poster presentations for Medical and Radiation Oncologists. Methods: A survey form including 40 questions was distributed to a total of 131 oncologists experienced in poster presentations. One hundred completed survey forms were included in the study. Descriptive statistics and modified thematic analyses were performed on the responses. Results: Overall 64% of the participants agreed that posters were a good medium for knowledge transfer. Some 88% agreed that concise and clear styled presentations would increase appealing interests for poster contents. Visual appearance was cited more influential than content of the subject; 70% of participants agreed that appearances of posters could help to draw more viewer attention. Of respondents, 63% believed that posters accompanied by their author were more attractive for congress attendees, and 33% of them declared that the halo effect of the poster presenter was also important. Conclusion: The present study indicated that intelligibility, appearance and visuality of posters are most important factors from the aspect of oncologist participants. Presenters must take into account these important points when preparing their academic posters.

• Journal of Microbiology and Biotechnology
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• v.14 no.4
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• pp.872-876
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• 2004

The plant pathogen Erwinia pyrifoliae was infected with bacteriophage PEa1(h), which produced a translucent halo plaque when grown on a lawn of E. pyrifoliae. To investigate the function of an exopolysaccharide (EPS)-depolymerase in the growth of E. pyrifoliae, an EPS-depolymerase gene was synthesized using the PCR method and sequenced. The synthesized gene was then transferred to E. pyrifoliae. The transformed E. pyrifoliae did not produce any ooze, and its growth was inhibited. However, the EPS-depolymerase did not appear to induce cell death. Accordingly, the present results suggest that an EPS-depolymerase may be effective in inhibiting the cell growth or infection of the pathogen E. pyrifoliae.

• Journal of the Korean Society of Clothing and Textiles
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• v.43 no.6
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• pp.779-794
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• 2019

This study examines the effects of brand belief of a mass offline retailer on the perceived value, attitude, and purchase intention toward the products of emerging fashion designer brands in the context of marketing collaborations between emerging fashion designer brands and a mass offline retailer. We invited 198 adults aged 20 to 59 to an online survey who were asked to read a news article and respond to a questionnaire. The results of structural equation modeling show that brand belief of a mass offline retailer positively influences the perceived value of the products of emerging fashion designer brands. The perceived value also positively influences the attitude toward the products that subsequently enhances purchase intention. The findings suggest that emerging fashion designer brands should strategically select a mass offline retailer as their collaboration partner by considering consumer perceptions of the retailer brand because the brand belief of the retailer may have a halo effect on a consumer evaluation of the products of emerging fashion designer brands.

• IEIE Transactions on Smart Processing and Computing
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• v.2 no.3
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• pp.130-139
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• 2013

This paper proposes a new approach for enhancing digital images based on red channel information, which has the most analogous characteristics to invisible infrared rays. Specifically, a red channel in RGB space is used to analyze the image contents and improve the visual quality of the input images but it can cause unexpected problems, such as the over-enhancement of reddish input images. To resolve this problem, inter-channel correlations between the color channels were derived, and the weighting parameters for visually pleasant image fusion were estimated. Applying the parameters resulted in significant brightness as well as improvement in the dark and bright regions. Furthermore, simple contrast and color corrections were used to maintain the original contrast level and color tone. The main advantages of the proposed algorithm are 1) it can improve a given image considerably with a simple inter-channel correlation, 2) it can obtain a similar effect of using an extra infrared image, and 3) it is faster than other algorithms compared without artifacts including halo effects. The experimental results showed that the proposed approach could produce better natural images than the existing enhancement algorithms. Therefore, the proposed scheme can be a useful tool for improving the image quality in consumer imaging devices, such as compact cameras.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.1
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• pp.34.2-34.2
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• 2021

SPT-CL J2106-5844 is the most massive galaxy cluster at z>1 discovered to date. It has been known to be an isolated system with a singular, well-defined halo. However, recent studies provide lines of evidence for its merging state. We strengthen the case with the multi-wavelength observations from ALMA, ACA, ASKAP, ATCA, and Chandra. With the sensitive, high resolution ALMA+ACA observations, we reconstruct the ICM pressure map from the thermal SZ effect. It reveals two main gas components that are associated with the mass clumps inferred from the weak-lensing analysis. Furthermore, the X-ray hardness map supports the bimodal gas distribution. With these multi-wavelength data, we probe the merger phase in SPT-CL J2106-5844.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.1
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• pp.33.2-34
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• 2018

Galaxies associated with massive groups/clusters are normally gas deficient in contrast to field galaxies. HI observations on such galaxies have revealed signs of violent gas stripping, the direct evidence of the environmental effect. At the same time, the notable number of passive galaxies at the cluster outskirts indicates the presence of pre-processing that makes galaxies gas-poor before entering clusters. We investigate the possible channels for the production of the gas deficient galaxies using the state-of-the-art cosmological hydrodynamic zoom-in simulations of 16 clusters (Choi&Yi). We find cluster effect and pre-processing together play an important role in producing the gas-poor galaxies and in both cases gas loss qualitatively agrees with the ram pressure stripping description. Among the currently gas-poor cluster galaxies, 34% are pre-processed before the cluster infall. They are mainly satellites that have undergone ram pressure stripping in group halos. 43% deplete quickly after arriving at cluster during their first approach to the center. Some of them are group halo satellites low in the gas at the infall compared to galaxies directly coming from the field. 24% retain gas even after their first pericentric pass mainly because they are falling into low mass clusters and/or they have a circular orbit that minimizes the ram pressure effect. This study highlights the importance of the past history of galaxies, especially in group halos, before joining the current cluster when understanding the excess of passive galaxies in clusters.

• Journal of dental hygiene science
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• v.2 no.1
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• pp.11-14
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• 2002

The purpose of this study was to investigate that the effect of Citrex and CPC on the growth of oral microorganism such as Streptococcus mutans KCTC 3065, Candida albicans KCTC 7122, and Staphylococcus aureus KCTC 1916 which were cariogenic, candidiasis(bleeding gum, dry mouth and tongue, thrush) and angular cheilitis inducing bacteria, respectively. The efficacy of complex of Citrex and CPC was determined in assays measuring Halo Test. The gargle containing Citrex(0.02%) and CPC(0.02%) demonstrated broad-spectrum anti-microbial properties, with activity against both Gram-positive and Gram-negative and a yeast(Candida albicans).