• 한국대기환경학회지
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• 제23권6호
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• pp.752-759
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• 2007

For an accurate measurement of aerosol particle size distribution using a differential mobility analyser (DMA), a new calculation process, capable of predicting the masses for the various kinds of water cluster ions generated from a bipolar ionizer, was prepared by improving the previous process. The masses for the 5 kinds of positive and negative water cluster ions produced from a SMAC ionizer were predicted by the improved calculation process. The aerosol particle charging ratios calculated by applying the predicted ion masses to particle charging equations were in good accordance with the experimentally measured ones, indicating that the improved calculation process are more reasonable than the previous one in a mass prediction of bipolar water cluster ions.

• 천문학회보
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• 제38권1호
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• pp.33.1-33.1
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• 2013

Galaxies undergo various processes in the cluster environment, which could affect their evolution. In particular, ram pressure due to intracluster medium (ICM) can effectively remove HI gas, which is a relatively diffuse form of interstellar medium (ISM). On the other hand, molecular gas is not expected to get easily stripped as atomic gas since it is denser and sitting well within the stellar disk in a deeper potential well. However, cluster galaxies are found to be redder and more passive in star formation activity compared to their field counterpart. This implies that molecular gas may also get affected somehow in dense environments. In this work, we investigate molecular gas properties of a sample of galaxies undergoing HI stripping due to the ICM. We present the 12/13 CO (2-1) data of four spiral galaxies in the Virgo cluster at different ram pressure stripping stages, obtained using the Sub Millimeter Array (SMA). CO morphology of the sample appears to be highly asymmetric and disturbed. Using the ratio of different lines, we probe the molecular gas temperature in different regions. We find higher gas temperature than the range normally found among field galaxies. We discuss how these distinct molecular gas properties may affect star formation and hence the evolution of the cluster galaxy population.

• 천문학회보
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• 제36권2호
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• pp.74.2-74.2
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• 2011

We probe the tidal perturbation parameter f of Virgo cluster galaxies. The goal is to measure the strength of tidal fields around individual galaxies to get better understanding gravitational processes that can affect galaxy evolution in the cluster environment. The f-value is defined as a logarithmic ratio between the net internal gravitational force within a galaxy and the external tidal force exerted by a neighboring galaxy. Hence, it provides one way to quantify the tidal field strength of galaxies, in particular, due to galaxy neighbors. In this study, we determine f-values of the VIVA galaxies, samples of the VLA Imaging study of Virgo galaxies in Atomic gas, using the Extended Virgo Cluster Catalog (EVCC) which is the most complete Virgo cluster catalog to date. With diagnostics based on the HI gas and R-band morphologies, we discuss the impact of the tidal fields on the evolution of the VIVA sample. Also, we compare the tidal field strength to the intra cluster medium (ICM) pressure for each sample galaxy to pin down environmental processes at work.

• 천문학회보
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• 제41권2호
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• pp.60.3-61
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• 2016

Galaxy morphology involves complex effects from both secular and non-secular evolution of galaxies. Although it is a final product of galaxy evolution, it gives a clue to the processes that the a galaxy has gone through. Galaxy clusters are the sites where the most massive galaxies are found, and thus the most dramatic merger histories are embedded. Our deep imaging program (${\mu}{\sim}28\;mag\;arcsec^{-2}$), KASI-Yonsei Deep Imaging Survey for Clusters (KYDISC), targets 14 Abell clusters at z = 0.016 - 0.14 using IMACS/Magellan telescope and MegaCam/CFHT to investigate cluster galaxies especially on low surface brightness features related to galaxy interactions. We visually classify galaxy morphology based on criteria related to secular or merger related evolution and find that the morphological mixture of galaxies varies considerably from cluster to cluster. Moreover it depends on the characteristics (e.g. cluster mass) of cluster itself which implies that environmental effects in cluster scale is also an important factor to the evolution of galaxies together with intrinsic (secular) and galaxy merger. Our deep imaging survey for morphological inspection of cluster galaxies with low surface brightness is expected to be a useful basis to understand the nature of cluster galaxies and their internal/external evolutionary path.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2004년도 총회 및 춘계학술발표회
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• pp.311-314
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• 2004

To identify the effect of geology and land use, the hydrogeochemical and multivariate statitstical analysis were executed for stream water collected in headwater region of Daecheong reservoir. Hydrogeochemical analysis was showed the effect of weathering process such as dissolution of calc-silicate minerals to hydrochemistry of stream water with contrasting geology. Cluster and principal components analysis can also help to identify the source of dissolved components in stream water.

• 한국환경생태학회지
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• 제29권2호
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• pp.236-249
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• 2015

The master plan of forest land management proposes forest watershed management that considers regional characteristics in order to overcome the problem of uniform forest land management. In order to manage the forest watersheds in Gyeonggi-do, this study classified 1,823 forest watersheds in Gyeonggi-do and attempted to understand their characteristics. It conducted a factor analysis and cluster analysis from the perspective of conservation value and development pressure using forest land indicators. In terms of conservation value, three factors were drawn: the topography factor, vegetation factor and public service factor, while in terms of development pressure, three factors were drawn: the easiness of development factor, economic benefits factor and development activity factor. Using these factors, forest watersheds were divided into three clusters in terms of conservation value while they were divided into three clusters in terms of development pressure. Using the results of the cluster analysis from a conservation-development perspective, the forest watersheds were classified into nine different types, and the characteristics were identified by each type. It is judged that the factors and clusters drawn as a result of the research accurately reflect the present conditions of Gyeonggi-do, and the nine types of forest watersheds have clear characteristics according to each type, which are judged to be utilized in forest management in the future.

• 한국정보과학회논문지:시스템및이론
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• 제33권7호
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• pp.421-428
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• 2006

본 논문에서는 지리적으로 분산되어 있는 클러스터 시스템자원들을 효율적으로 활용하기 위한 3-tier 구조의 원격 설치 및 백업 방안을 소개한다. 최근에는 클러스터 시스템이 수백 노드 이상의 대규모 시스템이며, 공인망과 사설망이 혼재되는 복잡한 네트워크 환경으로 구성되고 있다. 따라서, 대규모 클러스터 시스템에 적합한 클러스터의 OS 설치와 원격지에서 클러스터 노드의 장애를 효과적으로 복구하는 것이 중요하다. 하지만 기존의 2-tier 구조의 클러스터 설치 및 이미지 백업 방법들은 공인망과 사설망으로 구성되어 있는 클러스터의 경우, 원격지에서 접근과 관리가 어렵다. 이러한 문제점을 해결하고자 본 논문에서는 3-tier 구조의 RISE(Remote Installation Service Environment) 시스템을 제안하고자 한다. RISE 시스템은 2-tier 구조의 마스터 노드 역할을 관리노드(GRISE)와 지역관리노드(LRISE)로 나누어줌으로써 다양한 네트워크환경하에서 초기설치 및 장애 발생시 효과적으로 지원할 수 있으며, 관리노드와 지역관리 노드들의 동기화 기능을 통해 지역관리노드들의 안정성을 보장하고 있다. 64개 노드의 클러스터 시스템과 Gigabit 네트워크 시스템을 활용한 실험을 통하여, 1.86 GByte의 시스템 이미지를 5분 53초 안에 확보 할 수 있었고, 64개 노드 클러스터 시스템의 초기설치 작업을 평균 17분 38초 안에 완료할 수 있었다.

• 복식문화연구
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• 제8권1호
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• pp.30-39
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• 2000

The purpose of this study were to 1) identify types and levels of production environments, 2) classify apparel manufacturers based on production environments and 3) investigate relationship between characteristics of apparel manufacturers and production environment. Apparel manufacturer's characteristics included product line and the number of employees. For this study, the questionnaires were administered to 215 apparel manufacturers in seoul and Kyung-gi region from Feb. to Mar. 1998. Employing a sample of 201, data were analyzed by factor analysis, descriptive statistics, cluster analysis, cluster analysis, discriminant Analysis, and multivariate analysis of variance. The following are the results of this study : 1. The production environment was identified as three types such as complexity of product environment, uncertainty of demand/supply environment and uncertainty of worker environment. 2. Based on three types of the production environment, apparel manufacturers were classified into stable group, uncertain group and complicated group. 3. With respect to product line, men's wear manufacturers were lied the most high complexity of product environment, casual wear and knit wear were lied the most frequently uncertainty of worker environment. With respect to the number employees, apparel manufacturers comprising 50∼99 employees were lied the most high complexity of product environment, while those comprising 100∼299 employees the most high demand/supply environment.

• 농업과학연구
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• 제43권1호
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• pp.40-51
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• 2016

This study analyzed settlement condition changes of Chungcheong region's mountain area during 10 years, from 2001 to 2012. We performed factor analysis and cluster analysis of data from the 'Census for Mountain Area' carried out by the Korea Forest Service in 2001 and 2012. Factors 1, 2, 3, and 4 represent 'the superiority of non-agricultural income', 'the industrialized mountainous area', 'residential conveniences and benefits', and 'the use of forest resources', respectively. Clusters 1, 2, 3, 4, and 5 are categorized as 'non-agricultural income', 'various mass social functions', 'production of forest products', 'industrialized mountainous region', and 'ordinary mountain region', respectively. We suggest that cluster 1 has potential for development and should be promoted as a possible tourist attraction by digging up geographically unique themes. Cluster 2 has great potential for development and needs planned management through the maintenance or expansion of existing infrastructure. Cluster 3 has potential for development with various high value added industries uncovered. Cluster 4 shows vitality as it holds plenty of more job opportunities than other regions. Cluster 5 is deteriorating as a mountainous region because of an aging population, and it urgently demands development. For a decade, 45 of the 60 regions belonged to a single category, which are now differentiated broadly into two types: Firstly, deterioration changes to potential development and Secondly, vitality is differentiated into potential development and deterioration.

• 융합보안논문지
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• 제7권2호
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• pp.107-118
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• 2007

센서 네트워크는 다양한 환경에 배치되어 환경요소 감시 및 군사적으로 유용한 정보를 제공하는데 사용될 수 있다는 특징을 가지고 있지만, 여러 가지 보안상의 취약점을 갖고 있는 단점이 있다. 따라서 이러한 센서 네트워크의 안전성을 위해서는 반드시 보안 서비스가 요구되며, 센서 네트워크 노드간의 안전한 통신을 위해 보다 안전하고 효과적인 노드 관리 기법이 요구된다. 본 논문에서는 센서 네트워크에서의 센서 노드의 보안성이 요구되는 환경 및 그룹 키 관리기법에 적합한 효과적인 CH 및 클러스터링 기법을 제안한다. 먼저 각각의 노드들은 매 라운드 설정단계에서 BS와의 통신을 통하여 잔류 전력 및 암호 키를 이용한 인증 메시지를 전송하고 BS는 유효인증비율 및 잔류전력량을 반영하여 이 값들이 높은 노드를 CH로 선발한다. 이후 BS는 매 라운드 마다 이전라운드의 유효인증비율을 반영/누적 하여 적은 양의 에너지 소비로 안전한 클러스터 노드를 선발할 수 있는 기법을 제안한다.