• 천문학회보
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• 제42권1호
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• pp.52.1-52.1
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• 2017

Galaxy clusters are the most massive gravitationally bound systems and thus probably the most recent objects to form. One of promising routes to understand the assembly history of galaxy clusters is to measure observable quantities of components in clusters that are sensitive to the evolutionary state of the cluster. Recent deep observations on the nearby clusters show distinct diffuse intracluster light (ICL), that the light from stars are not bound any individual cluster galaxy, however until now this component has not been well studied due to its faint nature, with typical brightness of ~100 times fainter than the sky background. As shown in galaxy cluster simulation studies, the ICL abundance increases during various dynamical exchanges of galaxies such as the disruption of dwarf galaxies, major mergers between galaxies and the tidal stripping of galaxies. Thus, the ICL is an effective tool to measure the evolutionary stage of galaxy clusters. Moreover, the investigation of the ICL evolution mechanism will allow us understand the galaxy evolution process therein. In this pilot study, we target the Coma cluster, where the existing ICL studies are limited only in the central region. With large and uniform deep optical images from the Subaru telescope, available only recently (Okabe et al. 2014), we are developing a robust ICL measurement technique, extracting the ICL surface brightness and color profiles, which will allow us to study the origin of the ICL and its connection to the evolutionary history of the Coma cluster. For the next phase, we plan to utilize the plenty of spectroscopy data from the MMT telescope to compare ICL properties with the star formation history of the brightest cluster galaxies (BCG), and discuss the ICL formation mechanism of the Coma cluster by comparing the distribution of cluster galaxies with the distribution of diffuse light inside the Coma cluster.

• 산업클러스터
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• 제2권1호
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• pp.1-13
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• 2008

지역경제의 성공에 있어 산업클러스터의 중요성에 대한 증대된 인식에도 불구하고, 구산업지구에 대한 클러스터 정책의 효과성에 대해서는 그다지 많은 관심이 모이지 못했다. 이들 지역 중 상당수에서는 아직 산업클러스터가 작동하고 있거나 재도약을 위한 새로운 전략이 모색되고 있다. 본 연구는 구산업지구에서 대한 산업클러스터 정책의 효과성을 산업클러스터의 진화적 성격에 대한 이해로부터 찾으려 한다. 이를 위하여 유럽 구산업지구의 변환에 대한 선행연구들을 고찰하고, 어떻게 클러스터 정책이 주요한 정책수단으로 등장하게 되었는지 살펴본다. 본 연구는 또한 영국의 북동지 역에서 어떻게 철강산업의 공급체인이 형성되었는지 사례 연구를 통해 살펴본다. 마지막으로 본 연구의 결론은 클러스터 형성 과정에서의 정책적 개입의 타이밍을 어떻게 잡을 것인지를 보여주는 자료에 초점을 맞추고 있다.

• Communications for Statistical Applications and Methods
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• 제25권4호
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• pp.373-383
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• 2018

The spatial scan statistic is a widely used method to detect spatial clusters. The method imposes a large number of scanning windows with pre-defined shapes and varying sizes on the entire study region. The likelihood ratio test statistic comparing inside versus outside each window is then calculated and the window with the maximum value of test statistic becomes the most likely cluster. The results of cluster detection respond sensitively to the shape and the maximum size of scanning windows. The shape of scanning window has been extensively studied; however, there has been relatively little attention on the maximum scanning window size (MSWS) or maximum reported cluster size (MRCS). The Gini coefficient has recently been proposed by Han et al. (International Journal of Health Geographics, 15, 27, 2016) as a powerful tool to determine the optimal value of MRCS for the Poisson-based spatial scan statistic. In this paper, we apply the Gini coefficient to normal-based spatial scan statistics. Through a simulation study, we evaluate the performance of the proposed method. We illustrate the method using a real data example of female colorectal cancer incidence rates in South Korea for the year 2009.

• Journal of Microbiology and Biotechnology
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• 제21권11호
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• pp.1127-1142
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• 2011

The aim of this investigation was to select effective Pseudomonas sp. strains that can enhance the productivity of soybean-wheat cropping systems in Vertisols of Central India. Out of 13 strains of Pseudomonas species tested in vitro, only five strains displayed plant growth-promoting (PGP) properties. All the strains significantly increased soil enzyme activities, except acid phosphatase, total system productivity, and nutrient uptake in field evaluation; soil nutrient status was not significantly influenced. Available data indicated that six strains were better than the others. Principal component analysis (PCA) coupled cluster analysis of yield and nutrient data separated these strains into five distinct clusters with only two effective strains, GRP3 and HHRE81 in cluster IV. In spite of single cluster formation by strains GRP3 and HHRE81, they were diverse owing to greater intracluster distance (4.42) between each other. These results suggest that the GRP3 and HHRE81 strains may be used to increase the productivity efficiency of soybean-wheat cropping systems in Vertisols of Central India. Moreover, the PCA coupled cluster analysis tool may help in the selection of other such strains.

• 천문학회보
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• 제43권2호
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• pp.33.3-34
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• 2018

Galaxy clusters contain a diffuse component of stars outside galaxies, that is observed as intracluster light (ICL). Since the ICL abundance increases during various dynamical exchanges of galaxies, the amount of ICL can act as a measurement tool for the dynamical stage of galaxy clusters. There are two prominent ICL formation scenarios; one is related to the brightest cluster galaxy (BCG) major mergers, and the other to the tidal stripping of galaxies. However, it is still under debate as to which is the main ICL formation mechanism. In this study we improve on earlier observational constraints of the ICL origin, by investigating it in a massive fossil cluster at z~0.47. Fossil clusters are believed to be dynamically matured galaxy clusters which have dominant BCGs. Recent simulation studies imply that, BCGs have assembled 85~90% of their mass by z~0.4 (e.g., Contini et al. 2014). Thus our target is an optimal test bed to examine the BCG-related scenario. Our deep images and Multi-Object Spectroscopic observations of the target fossil cluster (Gemini North 2018A) allow us to extract the ICL distribution, ICL color map and ICL fraction to cluster light. We will present a possible constraint of the ICL origin and discuss its connection to the BCG and the host galaxy cluster.

• 산업클러스터
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• 제1권1호
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• pp.1-15
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• 2007

지역혁신과 클러스터 정책은 지역정책의 새로운 아젠다로서, 최근 여러 국가와 지역에서 관심을 갖는 주제이다. 여기서 우리의 주요 관심사는 지역혁신과 클러스터 정책을 어떻게 평가할 것인가, 그리고 그 평가에 있어 어떤 모델과 방법을 사용할 것인가라는 데에 모아진다. 1990년 이후 국가 및 지방정부에서는 개선된 정책을 수립하기 위한 지식 창출의 도구로서 정책평가를 강조해 왔다. 이 논문의 목적은 지역혁신과 클러스터 정책의 평가와 관련된 주요 논의를 요약하고, 더 나은 정책평가에 기여할 수 있는 방법론을 제안하는 데에 있다. 우선 지역혁신과 클러스터 정책을 개관하고 그 정책의 주요 특성과 정책평가로 제기되는 주요 과제를 보다 상세히 분석한다. 다음으로 현재 사용되는 평가 관행을 개선시키는 데 도움이 되는 몇 가지 방법을 제안한다. 마지막으로 지역혁신과 클러스터 정책을 평가하는 데 있어 고려해야 할 몇 가지 사항을 제시한다.

• 생명과학회지
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• 제13권5호
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• pp.590-595
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• 2003

The objective of this study was to assess of genetic variation within and between pumpkin species including Cucurbita maxima, C. moschata, C. pepo and C. maxima${\times}$C. moschata using RAPD markers. The 16 primers showed the amplification of 136 scorable fragments ranging from about 100 bp to 2300 bp. A total of 94 DNA fragments were polymorphic with an average 5.9 polymorphic bands per primer. A species $(C. maxima\timesC. moschata)$ has the highest number of polymorphic loci. Based on obtained data, UPGMA cluster analysis was conducted. Twenty pumpkin cultivars were classified into three large categories and identified genetic distance of cluster ranging from 0.38 and 1.00. Clustering was in accordance with the division of Curcurbitaceae into four species, C. maxima, C. moschata, C. pepo and C. $C. maxima\timesC. moschata$. Therefore, RAPD method may be essential tool for enabling discrimination of pumpkin cultivars.

• 한국수학사학회지
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• 제11권1호
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• pp.52-57
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• 1998

Since cluster analysis encompasses many diverse techniques for discovering structure within complex bodies of data, it has been employed as an effective tool in scientific inquiry. Recent works on cluster analysis softwares carried out by SAS, SPSS, S-PLUS and BMDP are briefly summarized and investigated in this paper. The inferred statistical package for windows executing a nay for data analysis in modern statistical techniques has several merits superior to other packages. Especially, S-PLUS can be designed and tried out much faster than other statistical packages. S-PLUS provides a graphic which is interactive, informative, flexible ways of looking at data. Also, if a statistical computation time is long and programs are complex, these can be shorten by providing interfaces to the UNIX systems (or C, Fortran).

• 대한임베디드공학회논문지
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• 제18권6호
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• pp.293-301
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• 2023

With the advancement of artificial intelligence and its various use cases, accessing it through edge computing environments is gaining traction. However, due to the nature of edge computing environments, efficient management and optimization of clusters distributed in different geographical locations is considered a major challenge. To address these issues, this paper proposes a centralization and automation tool called KubEVC-Agent based on Kubernetes. KubEVC-Agent centralizes the deployment, operation, and management of edge clusters and presents a use case of the data transformation for optimizing intra-cluster communication. This paper describes the components of KubEVC-Agent, its working principle, and experimental results to verify its effectiveness.

• 한국공작기계학회논문집
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• 제17권4호
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• pp.95-103
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• 2008

Diamond core drills are applied to drill difficult-to-cut materials. This paper proposes basic understanding of ceramic drilling mechanics and characteristics of main factors affecting tool life, tool wear, cutting force, and chipping thickness. In contrast to conventional drilling, the core drilling process make deep grooves on the workpiece. One difficulty of it is the evacuation of chips from the drilled groove. As the drilling depth increases, an increased amount of chips tend to cluster together and clog the groove. Eventually severe wear develops and diamond grits are separated from the drill body. To relieve the clogging problem and to evacuate chips from the groove easily, the helical drilling process is applied for the core drilling process. To analyze drilling characteristics and derive optimal drilling conditions, tool life, tool wear, cutting force, and chipping thickness are quantified through the monitoring system and the Taguchi method. Mathematical models for the tool life and chipping thickness are derived from the response surface method. Optimal drilling database has been constructed through the experimental models.