• The Bulletin of The Korean Astronomical Society
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• 제42권1호
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• pp.30.2-31
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• 2017

Compact elliptical (cE) galaxies are in a rare class of stellar systems characterized by high stellar densities, small sizes, high velocity dispersion, and high metallicity corresponding to elliptical galaxies. cE galaxies have been observed around massive galaxies, so they could be formed under strong influences of tidal stripping and truncation. However, the recent discovery of isolated cE galaxies requires the need of new formation scenarios. We aim at finding cE galaxies in various environments using SDSS DR12, and studying stellar population of cEs as function of environments. Based on the typical properties of cE galaxies, we selected cE candidates by restricting that low-luminosity Mg > 19.5 mag, small sizes Re < 700 pc, and high velocity dispersions ${\sigma}$ > $60kms^{-1}$. Since effect radii of cE candidates are mostly smaller than the seeing size of SDSS photometry, we calculated the effective radius by fitting a Sersic profile. In addition, we assumed that host galaxies have brightness with Mr < -21 mag, and an environmental parameter is computed as distances between cE galaxies and host-galaxies. We found 112 cE galaxies at z < 0.05, which have high sersic indices (mean value is 5.2) similar to the typical massive elliptical galaxies. Mgb values of cE galaxies increase as the distances from the host galaxies decrease. Especially, for cEs close to the host galaxies (NcE; $D_{host}$ < 300 pc), the Mgb values are similar to those of massive elliptical galaxies, which is consistent with the previous studies. On the other hand, cE galaxies distant from the host galaxies (DcE; Dhost >300 pc) have lower Mgb values than the conventional cE. The Mgb values follow the ${\sigma}$-Mgb relation of elliptical galaxies, and are connected to its faint end. This can be explained as a result of different merger histories for differing environments. For example, NcE galaxies are formed by tidal stripping by massive galaxies as suggested by previous studies, but DcE galaxies could be linked with high-redshift spheroids (e.g. red nuggets) which have not evolved into present-day elliptical galaxies because of the environmental influences.

• Korean Journal of Acupuncture
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• 제24권2호
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• pp.99-112
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• 2007

Objectives : It was to translate three neck and spinal pain disability questionnaires - the Neck Disability Index (NDI), the Neck Pain and Disability Scale (NPDS), and the Functional Rating Index (FRI) - into Korean language, and evaluate the psychometric properties of Korean versions of questionnaires to achieve a good cross-cultural adaptation. Methods : Forty (23 males, 17 females) subjects aged from 15 to 64 years old, participated to examine test-retest reliability. One hundred and eighty (76 males, 104 females) subjects with a primary diagnosis of non-specific neck pain and 81 healthy volunteers were undertaken to examine internal consistemcy, discriminative validity and longitudinal construct validity. Versions of each questionnaire in idiomatic modern Korean were developed using a procedure proposed by Beaton et al. (2000). To assess reliability, the Intraclass Correlation Coefficient (ICC $_{(2,1)}$) was calculated. Internal consistency was evaluated by Cronbach's alpha. Discriminative validity was examined with independent-group t-tests. Responsiveness was tested by calculating the effect size and standardized response mean for each questionnaire and using Pearson' s r and the area under the receiver operating characteristic curve analysis. Results : Test-retest reliability ofthe translated versions of the three disability questionnaires was excellent (ICC $_{(2,1)$ = 0.86-0.90). High internal consistency was found in the three disability questionnaires (Cronbach's alpha ranged from ${\alpha}=0.88$ for the FRI to ${\alpha}=0.96$ for the NPDS and 0.82 for the Short Form McGill Pain Questionnaire(SFMPQ)). the VAS subscale of the SFMPQ was found to be the most responsive of the subscales (ES=1.44, SRM=1.37). The VAS was also the most responsive pain and disability index in internal responsiveness analysis, although disability indices showed marginally better responsiveness when compared with external standards. No floor or ceiling effects were observed. Conclusions : It is concluded that the questionnaires were successfully translated and exhibit acceptable measurement properties, and may suggest that they are suitable for use in clinical and research application.

• Journal of electromagnetic engineering and science
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• 제18권1호
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• pp.63-69
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• 2018

This work demonstrates attenuation effects of plasma on waves propagating in the 26.5-40 GHz range. The effect is investigated via experiments measuring the transmission between two Ka-band horn antennas set 30 cm apart. A dielectric-barrier-discharge (DBD) plasma generator with a size of $200mm{\times}100mm{\times}70mm$ and consisting of 20 layers of electrodes is placed between the two antennas. The DBD generator is placed in a $400mm{\times}300mm{\times}400mm$ acrylic chamber so that the experiments can be performed for plasma generated under various conditions of gas and pressure, for instance, in air, Ar, and He environments at 0.001, 0.05, and 1 atm of pressure. Attenuation is calculated by the difference in the transmission level, with and without plasma, which is generated with a bias voltage of 20 kV in the 0.1-1.4 kHz range. Results show that the attenuation varies from 0.05 dB/m to 9.0 dB/m depending on the environment. Noble gas environments show higher levels of attenuation than air, and He is lossier than Ar. In all gas environments, attenuation increases as pressure increases. Finally, electromagnetic models of plasmas generated in various conditions are provided.

• Investigative Magnetic Resonance Imaging
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• 제24권2호
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• pp.76-84
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• 2020

Background: Determination of inter-method differences between clinically available volumetry methods are essential for the clinical application of brain volumetry in a wider context. Purpose: The purpose of this study was to examine the inter-method reliability and differences between the Siemens morphometry (SM) software and the NeuroQuant (NQ) software. Materials and Methods: MR images of 86 subjects with subjective or objective cognitive impairment were included in this retrospective study. For this study, 3D T1 volume images were obtained in all subjects using a 3T MR scanner (Skyra 3T, Siemens). Volumetric analysis of the 3D T1 volume images was performed using SM and NQ. To analyze the inter-method difference, correlation, and reliability, we used the paired t-test, Bland-Altman plot, Pearson's correlation coefficient, intraclass correlation coefficient (ICC), and effect size (ES) using the MedCalc and SPSS software. Results: SM and NQ showed excellent reliability for cortical gray matter, cerebral white matter, and cerebrospinal fluid; and good reliability for intracranial volume, whole brain volume, both thalami, and both hippocampi. In contrast, poor reliability was observed for both basal ganglia including the caudate nucleus, putamen, and pallidum. Paired comparison revealed that while the mean volume of the right hippocampus was not different between the two software, the mean difference in the left hippocampus volume between the two methods was 0.17 ml (P < 0.001). The other brain regions showed significant differences in terms of measured volumes between the two software. Conclusion: SM and NQ provided good-to-excellent reliability in evaluating most brain structures, except for the basal ganglia in patients with cognitive impairment. Researchers and clinicians should be aware of the potential differences in the measured volumes when using these two different software interchangeably.

• Korean journal of applied entomology
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• 제60권1호
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• pp.115-122
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• 2021

Pollinators are not only crucial for plant reproduction, but also important for crop production. These pollinators are affected by the diversity of plants within orchards. Thus, the study investigated the effect of blooming on the ground cover on pollinator diversity, network, fruiting rates and subsequent apple size during harvest season in apple blooming period. Total ten orchards were selected; Five with ground covered mostly by dandelion while the another five without ground cover. The orchards with dandelion bloom showed 16 pollinator groups and 801 pollination network interaction, while 14 pollinator groups and 589 interaction were found from orchards without ground cover blooms. es. Overall pollinators' abundances were not different. But bumble bees and caliphorid flies were more abundant in orchards with ground cover blooming. There was no significant in fruiting rates, but the apple size was significantly bigger in orchards with ground cover. These results may indicate that blooming on the ground cover during apple flowering season would increase pollinator diversity and influence fruit quality later on in apple orchards, and pose importance of floral diversity for sustainable apple production system.

• Journal of the Korean Recycled Construction Resources Institute
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• 제10권4호
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• pp.359-366
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• 2022

In this paper, the effect of compression levels on the strengths of porous concrete using bottom ash aggregates was analyzed. Coal bottom ash (CBA) was used as aggregate in porous concrete in this study. The aggregate size types used in the CBA concrete mixtures were catagorized into two different ones. One included only a single aggregate particle size and the other included hybrid aggregate particles mixed at a ratio of 8:2 volume proportion. The water-binder ratio was fixed at 0.30, and the compression levels were applied at 0.5, 1.5, and 3.0 MPa valu es to fabricate a porou s concrete specimen. The total porosity, compressive, splitting tensile, and flexural tensile strengths were tested and analyzed. When the compression level increased, the total porosity decreased, meanwhile the compressive, split tensile, and flexural tensile strengths increased. The total porosity of concrete using hybrid aggregate was lower and the strength was larger than those of concrete using single-type aggregate. Finally, the correlation between the total porosity, compressive, split tensile, and flexural tensile strengths of porous concrete were presented. The total porosity and strength characteristics showed an inversely proportional correlation.