• Journal of The Korean Astronomical Society
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• v.37 no.5
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• pp.461-463
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• 2004

We investigate the role of secondary electrons in galaxy clusters and in ultra-luminous infrared galaxies (ULIGs). The radio emission in galaxy clusters and ULIGs is believed to be produced by the synchrotron radiation of relativistic electrons. Nonetheless, the sources of these relativistic electrons are still unclear. Relativistic secondary electrons can be produced from the hadronic interactions of cosmic-ray nuclei with the intra-cluster media (ICM) of galaxy clusters and the dense molecular clouds of ULIGs. We estimate the contribution of the secondary electrons in galaxy clusters and ULIGs by comparing observational results with theoretical calculations for the radio emission in these sources. We find that the radio halos of galaxy clusters can not be produced from the secondary electrons; on the other hand, at least for some ULIGs, the radio emission can be dominated by the synchrotron emission of the secondary electrons.

• Journal of The Korean Astronomical Society
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• v.37 no.5
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• pp.533-541
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• 2004

The origin of magnetic fields in the universe remains an outstanding problem in cosmology. We propose that these fields are produced by shocks during the large-scale structure formation. We discuss the mechanism of the field generation via the counter-streaming (Weibel) instability. We also show that these Weibel-generated fields are long-lived and weakly coupled to dissipation. Subsequent field amplification by the intra-cluster turbulence may also take place, thus maintaining the magnetic energy density close to equipartition.

• International Journal of Human Ecology
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• v.5 no.2
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• pp.61-80
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• 2004

The introduction of the Internet in homes had an effect on family systems. The purpose of this study is to investigate the changes in family systems due to Internet use in South Korea. This study classified the types of changes in the family systems and analyzes the characteristics of each type. Systems approach provides the theoretical framework for this study. First, the cluster analysis demonstrated the three types of the changes in the family subsystems due to housewives' Internet use: 'positive changes', 'negative changes', and 'no changes'. Second, there are different characteristics among the types of changes according to demographic, Internet-related, and intra-system dynamic factors. These results suggest several implications for public policy. To utilize the Internet as a useful tool to improve the quality of family life, housewives must have the ability to control the Internet use and to manage their resources. In order to enhance their abilities of using the Internet, it may be necessary for the government to provide public educational programs for housewives.

• The Plant Pathology Journal
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• v.19 no.5
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• pp.221-226
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• 2003

Twenty universal rice primers (URPs) were used to detect PCR polymorphisms in 25 isolates of six different Alternaria species producing host specific toxins (HST). Eight URPs could be used to reveal PCR polymorphisms of Alternaria isolates at the intra- and inter-species levels. Specific URP-PCR polymorphic bands that are different from those of the other Alternaria spp. were observed on A. gaisen and A. longipes isolates. Unweighted pair-group method with arithmetic mean (UPGMA) cluster analysis using 94 URP polymorphic bands revealed three clustered groups (A. gaisen group, A. mati complex group, and A. logipes group).

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.87.2-87.2
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• 2012

The HI absorption against bright continuum source provides a unique opportunity to measure spin temperature of the neutral hydrogen gas. We find three cases among the sample of the VIVA (VLA Imaging of Virgo galaxies in Atomic gas) study with self absorption of strong central continuum by galactic HI gas. Using the HI flux ratio of emission and absorption, we constrain the spin temperature of the neutral hydrogen gas on their disk. The HI absorption is marginally resolved in these galaxies, which also allows us to probe the kinematics of the absorbing gas. All three galaxies are severely stripped in HI due to the intra cluster medium (ICM). We discuss the influence of environmental processes on the temperature and kinematics of HI in these galaxies.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.1
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• pp.58.2-58.2
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• 2011

Park, Gott, & Choi (2008) found that when a galaxy is located within the virial radius from its closest neighbor and the neighbor is an elliptical, the probability of the galaxy to be an elliptical is very sensitive to the large-scale background density over a few Mpc scales. They suggested that the large-scale dependence can be arise if the temperature of a diffuse hot gas held by elliptical galaxies are higher in higher density environment. In this study, to understand the large-scale environment affects the X-ray properties of individual galaxies, we investigated the dependence of the X-ray luminosities of the elliptical galaxies on the large-scale environment using X-ray and optical data which we selected from the ROSAT All-Sky Survey and the Sloan Digital Sky Survey Data Release 7. To exclude galaxies embedded in an intra-group/cluster medium which could enhance their observed X-ray luminosity, we used isolated elliptical galaxies.

• Proceedings of the Korea Information Processing Society Conference
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• 2010.11a
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• pp.1725-1727
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• 2010

멀티 코어 또는 매니 코어 기반 시스템을 클러스터 시스템의 단위 노드로 활용하면서 클러스터 시스템은 다양한 형태의 노드내(Intra-node)및 노드간(Inter-node)네트워크를 가지게 되었다. 최적화된 어플리케이션의 개발을 위해서는 해당 시스템의 이러한 네트워크적 특징을 미리 파악하는 것이 중요하다고 할 수 있다. 본 논문에서는 서로 다른 계산 노드를 사용하는 클러스터 시스템에서 네트워크 성능을 비교 분석하였다.

• Korean Journal of Environmental Biology
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• v.22 no.1
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• pp.66-74
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• 2004

In order to clarify intra-and inter-specific variation of Korean Rana species, the partial DNA sequences of mitochondrial 16S rDNA gene were determined from 6 Korean and 1 Japanese Rana species, DNA sequences from Korean and Japanese species were comparison-analysed within, and also with the sequences from three species of Japanese brown frogs. DNA similarities were calculated as 91.3∼97.3％ among brown frog (R. amurensis coreana, R. dybowskii and R. huanrenensis), as 96.11∼97.26％ among pond frogs (R. nigromaculata and R. planeyi chosenica). Genetic distance of pond frog and wrinkle fyog (R. rugosa) were near than that of pond frog and brown frog. Two clusters were formed brown frogs and the other group by neigh-bor-joining and maximum-likelihood analysis, also the populations of R. nigromaculata were well distinguished between Korean peninsula and Korean island. But result from maximum-likelihood analysis slightly differed from neighbor-joining to cluster of R. rugosa. Further analyses for their population will be necessary to study the phylogenetic status.

• Health Policy and Management
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• v.3 no.2
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• pp.100-129
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• 1993

This study is designed to find out some intra-clinic factors affecting the content of practice provided by primary care physicians in Korea, and proposed factors in this study are characteristcs of each private clinc --- physician-related variables(age, sex, specialty), bfed-related variables for inpatient care, laboratory-related variables for precise diagnosis. We have tried to estimate the difference of disease entities cared by each primary care physician according to above factors by analyzin gdisease data claimed during one month(April, 1992) to National Federation of Medical Insurance. The diagnosis codes by ICD-9 in the research disease data were reclassified to 'diagnosis clusters' by virtue of clinical similarities for effective analyses. We have converted frequent-tsing ICD-9 codes to 86 diagnosis clusters, which incorporated 97.4 percents of all ambulatory visits to private clinics. This result means proposed diagnosis-cluster method is effective tool for analysis of the content of ambulatory medical care carried out by primary care physicians. Comparisons and analyses of multiple diagnosis-clusters made on the basis of presented factors were done and the results were as follows; - Major factors affecting the difference between diagnosis-cluster pattern by each variables were phyusician's age, sex, specialty and bed counts of each private clinic for inpatient care and the size of laboratories of each clinic. - Middle aged(30th to 40th) group physicians are providing more comprehensive care than 20th or above 50th aged groups. Male physicians are more adequate for comprehensive care than female physicians, because woman-doctors are providing narrow-spectrum care. The content of practice of obstetricians and gynecologists shows much difference from primary medical practice, and they cannot be included in primary care physician, this study suggested. Pediatricians are also providing short-spectum acre, and nearly all visits to pediatricians were incorporated only 2-3 diagnosis-clusters. General surgeons' practices are very similar to general practioners' or family physicians' practices, the means they are providing primary care rather than special surgical care. And small number of beds(under 5 beds) and only basic(2-3 sorts of)diagnostic apparatuses are sufficient for primary physicians' clinic to carry out primary care. In conclusion, to reinforce primary care department in Korea, there must be support with health policy to expand office-based primary care practice-- with small number of beds for inpatient care and only basic laboratories-- provided by general practitioner of family physician.

• Information Systems Review
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• v.19 no.4
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• pp.43-62
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• 2017

This study investigates the effect of bonding and bridging social capital on the technological innovation performance in the Pangyo Techno Valley. In particular, we consider the information technology (IT) usage in industrial cluster as an antecedent of social capital. IT instigates the intra and extra communication and information sharing between employees, thereby promoting the formation of a network of various members. Results show that the IT usage factor positively affects both bridging and bonding social capital, but an evident difference exists among the effects of social capital on the technological innovation performance. In case of Pangyo industrial cluster, bridging social capital exerts significant effect on the technological innovation performance, whereas bonding social capital shows insignificance. Bridging social capital is composed of the interactions of various networks. Bonding social capital is based on the strong tie from trust and internal cooperation. Results are related with the characteristics of Pangyo Techno Valley, where various IT ventures need active communication and information sharing with other organizations for technological innovation performance.