• 천문학논총
• /
• 제7권1호
• /
• pp.39-50
• /
• 1992

A velocity inhomogeneity, which is the regional preponderence of either radial or tangential orbits, is searched with the new technique proposed by Kim (1992) for Coma, Hydra I, and Abell 2256 cluster of galaxies. Conspicuous inhomogeneities are found in the Coma and A2256 which X-ray isophotes are indicative for their underlying potentials being ellipitcal in shape, Even in their central regions, zones that are dominated by radial orbits are clearly distinguishable from that of the tangential orbits, and defining the cluster 'equator' as the direction of maximum elongation of the X-ray isophotes, radial orbits dominate along this direction whereas tangential orbits dominate the 'polar' zones. Merger events that are evidenced in X-ray observations occur in the equatorial zones of Coma and A2256, suggesting preponderence of radial orbits in the zones, which is in good agreement with their velocity structures. On the other hand, the inhomogeneity in Hydra I turns out to be insignificant in the central regions and this is just what is expected from a cluster whose X-ray isophotes is nearly circular. The velocity distribution in regions further out, however, shows significant inhomogeneity and this seems to support the previous results that this cluster is likely to have substructures and velocity anisotropy.

• 한국인터넷방송통신학회논문지
• /
• 제17권3호
• /
• pp.107-114
• /
• 2017

클러스트-트리 무선센서네트워크에서 비콘활성화 모드일 때 비콘 충돌은 아주 중요한 문제가 되고 있다. 본 논문에서는 비콘 충돌 현상을 회피하고 네트워크 확장성을 제공하기 위하여 멀티채널 시분할 스케줄링 기법을 제안한다. 코디네이터는 할당된 채널들과 타임슬롯들에 대한 정보를 포함하고 있는 비콘프레임을 방송하는 역할을 한다. 이를 통해 새로운 노드는 자신의 채널과 타임슬롯을 결정하게된다. 제안 방식의 성능을 전형적인 지그비 방식과 비교한다. 제안 방식은 클러스트 트리 무선센서네트워크상에서 비콘 충돌을 방지하고 네트워크 확장면에서 효과적으로 구성이 가능하게 한다.

• 천문학회보
• /
• 제36권2호
• /
• pp.117.2-117.2
• /
• 2011

We probe 12CO J=2-1 and 13CO J=1-0 properties of a Virgo disk galaxy, NGC 4402 which is located near the cluster center. Our goal is to study the impact of intra cluster medium (ICM) on the molecular gas of a galaxy in the cluster environment. It has been believed that cluster galaxies are deficient in atomic hydrogen gas (HI gas) compared to their field counterparts and now there is much evidence that low density ISM can be easily removed by ram pressure caused by ICM wind. Meanwhile, no significant molecular gas deficiency of the cluster galaxy population has been found yet they show overall lower star formation rate than galaxies in the field, and it is still controversy whether dense ISM can be also stripped by the ICM wind or not. NGC 4402 with truncated HI disk($D_{HI}/D_{opt}$ ~ 0.75 and only 36%of HI gas compare to field galaxies of a similar size) and a disturbed gas morphology, appears to have strong ongoing ram pressure. Using high resolution 12 and 13CO data of NGC 4402 from a Sub Millimeter Array (SMA), we probe the molecular gas properties under strong ICM pressure. We discuss how its star formation activity and hence the global color of NGC4402 would be changed in the future.

• Journal of Microbiology and Biotechnology
• /
• 제17권5호
• /
• pp.830-839
• /
• 2007

Pradimicins are potent antifungal antibiotics having an unusual dihydrobenzo[$\alpha$]naphthacenequinone aglycone substituted with D-alanine and sugars. Pradimicins are polyketide antibiotics produced by Actinomadura hibisca P157-2. The gene cluster involved in the biosynthesis of pradimicins was cloned and sequenced. The pradimicin gene cluster was localized to a 39-kb DNA segment and its involvement in the biosynthesis of pradimicin was proven by gene inactivation of prmA and prmB(ketosynthases $\alpha\;and\;\beta$). The pradimicin gene cluster consists of 28 open reading frames(ORFs), encoding a type II polyketide synthase(PKS), the enzymes involved in sugar biosynthesis and tailoring enzymes as well as two resistance proteins. The deduced proteins showed strong similarities to the previously validated gene clusters of angucyclic polyketides such as rubromycin, griseorhodin, and fredericamycin. From the pradimicin gene cluster, prmP3 encoding a component of the acetyl-CoA carboxylase complex was disrupted. The production levels of pradimicins of the resulting mutants decreased to 62% of the level produced by the wild-type strain, which indicate that the acetyl-CoA carboxylase gene would have a significant role in the production of pradimicins through supplying the extender unit precursor, malonyl-CoA.

• 한국학교ㆍ지역보건교육학회지
• /
• 제21권1호
• /
• pp.75-89
• /
• 2020

Objects: The purpose of this study was to examine the differences of college students' big-five personality factors, academic adaptation, and psychological well-being according to cluster types based on the grit. Methods: The participants of this study were 190 college students. All variables were evaluated by self-report of college students. The data were analyzed by one-way ANOVA and two-step clustering statistics using SPSS 21.0. Results: First, a cluster analysis on a sample of 190 college students revealed four clusters: the more highly grit group, higher tenacity group, higher consistency of interests, and the less grit group. Second, there were significant differences of 190 college students' big five personality factors, academic adaptation, and psychological well-being according to cluster types based on the grit. Conclusions: These findings can be used as an important contribution to further research and educational practices for promoting the grit in college students. Also it suggests the need for health education to increase the psychological well-being of college students.

• 식품보건융합연구
• /
• 제5권4호
• /
• pp.1-10
• /
• 2019

Significant low knowledge and poor attitudes on complementary feeding undermine the practices. This study was a cluster randomized controlled trial in which 284 study participants were assigned into two groups. One intervention group and a control group in a ratio of 1:1. Nutrition education on complementary feeding was carried out among the caregivers in the intervention group but the caregivers in the control group were not educated. To determine complementary feeding knowledge and attitudes, data was collected from caregiver at baseline, midline and at endline using researcher-administered questionnaires. Quantitative data were analyzed using SPSS version 22.0. From the analysis, there was a significant difference in complementary feeding knowledge of the caregivers after the intervention. The baseline difference was -0.06, the midline difference was 3.85 the endline difference was 4.00 and the DID of the baseline and endline was 4.06 which was significant at p=0.001. There was a significant difference in the attitude of the caregivers towards complementary feeding at baseline (-0.14), midline (2.09), endline (3.82) and the DID of baseline and endline was 3.96 which was significant at p=0.001. The intervention improved the caregivers' knowledge on complementary feeding and it improved the attitudes of the caregivers towards adequate complementary feeding.

• 한국산학기술학회논문지
• /
• 제19권12호
• /
• pp.480-490
• /
• 2018

본 연구는 청소년을 대상으로 하여 분노표현의 하위차원인 분노조절, 분노억제 및 분노표출 방식 별로 군집 양상을 구분하고, 간 군집 별로 우울과 공격성, 부정정서강도에 있어서 어떠한 차이가 나타나는지 살펴보고자 하였다. 이를 위해 남녀 중학생을 대상으로 설문조사를 진행하고 총 296명의 자료를 분석하였다. 연구 결과, 첫째, 분노조절, 분노억제 및 분노표출에 대한 군집분석 결과, 네 개의 프로파일 군집이 추출되었다. 군집 1은 '억제 및 표출형 분노조절형', 군집 2는 '분노억제 및 표출형', 군집 3은 '분노처리 미숙형', 군집 4는 '표출적 분노조절형'으로 구분되었다. 둘째, 이러한 네 개의 군집 별로 우울과 공격성, 부정정서 강도의 차이가 유의하게 나타났다. 즉, 군집 4인 '표출적 분노조절형'이 다른 군집들에 비해 유의하게 더 높은 우울감을 나타내었고, 군집 3인 '분노처리 미숙형'은 다른 군집들보다 더 큰 공격성을 나타내었다. 한편, 군집 2인 '분노억제 및 표출형'이 군집 4인 '표출적 분노조절형'보다 부정정서강도가 더 높았다. 이러한 결과를 통해, 청소년 교육 및 상담을 통한 시사점에 대해 논의하였다.

• 한국발생생물학회지:발생과생식
• /
• 제17권4호
• /
• pp.363-367
• /
• 2013

PCR analysis generated on the genetic data showed that the geographic hairtail (Trichiurus lepturus) population from Korea in the Yellow Sea was more or less separated from geographic hairtail population from China in the South Sea. The average bandsharing value ($mean{\pm}SD$) within hairtail population from Korea showed $0.859{\pm}0.031$, whereas $0.752{\pm}0.039$ within population from China. Also, bandsharing values between two hairtail populations ranged from 0.470 to 0.611, with an average of $0.542{\pm}0.059$. As compared separately, the bandsharing values of individuals within hairtail population from Korea were comparatively higher than those of individuals within population from China. The hierarchical dendrogram resulted from reliable oligonucleotides primers, indicating two genetic clusters composed of cluster 1 (KOREANHAIR1~KOREANHAIR11) and cluster 2 (CHINESEHAI12~CHINESEHAI22). The genetic distances between two geographic populations ranged from 0.038 to 0.476. Individual No. 11 within hairtail population from Korea was genetically closely related with No. 10 (genetic distance=0.038). The longest genetic distance (0.476) displaying significant molecular difference was also between individual No. 01 within hairtail population from Korea and No. 22 from Chinese. In the present study, PCR analysis has revealed significant genetic distances between two hairtail population pairs (P<0.05).

• Macromolecular Research
• /
• 제14권4호
• /
• pp.449-455
• /
• 2006

Ionic cluster mimic, polymer electrolyte membranes were prepared using polymer composites of crosslinked poly(vinyl alcohol) (PVA) with sulfated-${\beta}$-cyclodextrins (${\beta}-CDSO_3H$) or phosphated-${\beta}$-cyclodextrins (${\beta}-CDPO(OH)_2$). When Nafion, developed for a fuel cell using low temperature, polymer electrolyte membranes, is used in a direct methanol fuel cell, it has a methanol crossover problem. The ionic inverted micellar structure formed by micro-segregation in Nafion, known as ionic cluster, is distorted in methanol aqueous solution, resulting in the significant transport of methanol through the membrane. While the ionic structure formed by the ionic sites in either ${\beta}-CDSO_3H$ or ${\beta}-CDPO(OH)_2$ in this composite membrane is maintained in methanol solution, it is expected to reduce methanol transport. Proton conductivity was found to increase in PVA membranes upon addition of ionized cyclodextrins. Methanol permeability through the PVA composite membrane containing cyclodextrins was lower than that of Nafion. It is thus concluded that the structure and fixation of ionic clusters are significant barriers to methanol crossover in direct methanol fuel cells.

• 한국IT서비스학회지
• /
• 제16권1호
• /
• pp.119-138
• /
• 2017

Mobile easy payment is a term for using mobile devices to facilitate financial transactions. Mobile easy payment is a quickly emerging practice, supported by the dramatic increase of mobile phone or device users around the world. The purpose of this study is to classify user's group of the mobile easy payment service by their lifestyle based on I-VALS type and to investigate differences in usage behavior among the user groups. For empirical study, a questionnaire survey was carried out with users of mobile easy payment services using the Internet from June 7 to 10 in 2016. We conducted factor analysis for I-VALS, usage factors, satisfaction factors. We also performed cluster analysis for group classification, and analysis of variance, cross analysis to compare the different usage behavior among the user groups. In analysis results, first three cluster appeared including "ICT task-oriented group", ICT positive and socialities oriented group", "ICT leader-oriented group". Second, it was found significant differences among the clusters about factor of "easy of use", "securities", "universality", "satisfaction". Third, we showed that there were significant differences in time first used the service. Based on these findings, we provide practical implications. Results of our study can be expected to provide the basis of differentiated marketing strategy of mobile easy payment services.