• Communications for Statistical Applications and Methods
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• 제17권4호
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• pp.591-598
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• 2010

설문문항에는 유사한 문항이나 중복문항이 있는 경우들이 있다. 본 연구에서는 전체 문항의 응답패턴을 군집분석하여 군집의 성격을 파악하고, 유사한 문항을 묶어 대표 문항을 찾는 방법을 시도하였다. 문항의 유사정 측정은 상호정보를 이용하였고 군집분석과 다차원척도법을 이용하여 대표 문항을 찾는 방법을 제안 하였으며 엔트로피를 이용하여 대표 문항을 평가하였다.

• 천문학회지
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• 제29권spc1호
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• pp.137-138
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• 1996

The first large-format CCD color-magnitude diagram (CMD) in the B and V passbands is presented for the Galactic globular cluster M53 (NGC 5024). We have discovered 117 new blue straggler (BS) candidates in the field of M53. The analysis of bright BS stars (V <19.0) clearly shows a bimodal radial distribution, with a high frequency in the inner and outer regions. The distribution is similar to that found in M3, a globular cluster with similar central density and concentration.

• 한국결정성장학회:학술대회논문집
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• 한국결정성장학회 2000년도 Proceedings of 2000 International Nano Crystals/Ceramics Forum and International Symposium on Intermaterials
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• pp.127-142
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• 2000

The charged cluster model states that chemical vapor deposition (CVD) begins with gas phase nucleation of charged clusters followed by cluster deposition on a substrate surface to form a thin film. A two-chambered CVD system, separated by a 1-mm orifice, was used to study gold deposition by thermal evaporation in order to determine if the CCM applies in this case. At a filament temperature of 1523 and 1773 K, the presence of nano-meter sized gold clusters was found to be positive and the cluster size and size distribution increased with increasing temperature. Small clusters were found to be amorphous and they combined with clusters already deposited on a substrate surface to form larger amorphous clusters on the surface. This work revealed that gold thin films deposited on a mica surface are the result of the sticking of 4-10 nm clusters. The topography of these films was similar to those reported previously under similar conditions.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2001년도 추계 학술대회논문집
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• pp.58-62
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• 2001

Aparallel computing environment was constructed based on Windows 2000 operating system. This cluster was configured using Fast-Ethernet system to hold up together the clients within a network domain. For the parallel computation, MPI implements for Windows such as MPICH.NT.1.2.2 and MP-MPICHNT.1.2 were used with Compaq Visual Fortran compiler which produce a well optimized executives for x86 systems. The evaluation of this cluster performance was carried out using a preconditioned Navier-Stokes code for the 2D analysis of a compressible and viscous flow around a compressor blade. The parallel performance was examined in comparison with those of Linux clusters studied previously by changing a number of processors, problem size and MPI libraries. The result from the test problems presents that parallel performance of the low cost Fast-Ethernet Windows cluster is superior to that of a Linux cluster of similar configuration and is comparable to that of a Myrinet cluster.

• 한국임상수의학회지
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• 제31권4호
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• pp.288-292
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• 2014

A critical assumption of the standard sample size calculation is that the response (outcome) for an individual patient is completely independent to that for any other patient. However, this assumption no longer holds when there is a lack of statistical independence across subjects seen in cluster randomized designs. In this setting, patients within a cluster are more likely to respond in a similar manner; patient outcomes may correlate strongly within clusters. Thus, direct use of standard sample size formulae for cluster design, ignoring the clustering effect, may result in sample size that are too small, resulting in a study that is under-powered for detecting the desired level of difference between groups. This paper revisit worked examples for sample size calculation provided in a previous paper using nomogram to easy to access. Then we present the concept of cluster design illustrated with worked examples, and introduce design effect that is a factor to inflate the standard sample size estimates.

• 천문학회보
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• 제43권1호
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• pp.60.3-61
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• 2018

Abell 115 is a renowned cluster merger at z=0.197. It exhibits an asymmetric X-ray distribution with cometary tails and a megaparsec-sized radio relic stretching in the northeastern direction from the core of the northern cluster. Many observations have concluded that this cluster merger has a large impact parameter, but there has been no numerical analysis on the structure of Abell 115. In this study, we simulate Abell 115 with Gadget2 N-body/SPH code to reproduce the X-ray and weak lensing features of Abell 115. We find a new plausible merger scenario of Abell 115, wherein the northern cluster is currently in an outgoing phase. The predicted X-ray emission has a similar morphology to the observed tail of the northern cluster. However, in order to reproduce the observed line-of-sight velocity and projected distance while maintaining the two systems gravitationally bound, the system should possess a large projection angle, which makes the shock look considerably more diffused than the observed radio relic.

• Journal of the Korean Data and Information Science Society
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• 제14권4호
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• pp.725-736
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• 2003

To provide the information needed to make a decision, it is important to know the relationship or pattern between variables in database. Grouping objects which have similar characteristics of pattern is called as cluster analysis, one of data mining techniques. In this study, it is compared with several partitioning clustering algorithms, based on the statistical distance or total variance in each cluster.

• 대한지리학회지
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• 제52권1호
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• pp.55-71
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• 2017

이 논문은 산업클러스터의 개념과 요건을 밝히고 이러한 요건에 비추어 산업클러스터의 범위를 구체화 하는데 목적을 두고 있다. 나아가 산업클러스터와 관련된 용어들을 전반적으로 비교 검토하여 그것들의 의미를 명확히 하고 그 차이를 규명하려 한다. 필자는 M. Porter의 클러스터 개념이 전문화된 산업집적지를 설명하는 가장 간명하고 적실한 개념으로서, 산업지구와 신산업지구, 유연적 생산집적지를 포괄하는 광의적 개념이라고 파악한다. 하지만 그것이 집적과 동일한 의미나 범주를 갖는다고는 보지 않는바, 클러스터 현상은 집적 중에서 산업집적에 해당하며 산업집적 중에서 동종 혹은 연관 산업의 집적과 연계를 의미하는 것이다. 한편으로 필자는 이 특징적인 산업집적 현상에 대해 클러스터 보다는 산업클러스터라는 용어가 적실하다고 판단한다. 클러스터라는 용어는 그 개념에 비해 지나치게 포괄적이어서 오해와 오용의 소지가 적지 않은 것이다. 클러스터는 산업클러스터 이외에 정치 행정클러스터, 예술클러스터, 과학연구클러스터 등을 포함할 수 있다. 더하여 본 연구는 산업클러스터와 비산업클러스터 사이에 준산업클러스터 개념을 도입하여 산업클러스터의 범주를 보다 구체화하려 하였으며 이러한 관점에서 다양한 산업클러스터 사례들을 분석하였다.

• 천문학회지
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• 제29권2호
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• pp.171-179
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• 1996

We have obtained the J K images of the central region of the globular cluster M3 (NGC5272), using the $256\pm256$ InSb array. We present JK photometry of bright red giant branch stars in the central $2'.2\pm2'.2$ region of M3. The infrared color-magnitude diagrams are presented. The comparison of the red giant branch of M3 with that of M13 confirms that both globular clusters have similar metal abundances.

• 유통과학연구
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• 제14권1호
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• pp.67-74
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• 2016

Purpose - In this paper, the degree of similarity and dissimilarity between pairs of 50 major cities in China can be shown on the basis of three evaluation variables(internet businessman index, internet shopping index and e-commerce development index). Dissimilarity distance matrix is used to analyze both similarity and dissimilarity between each fifty city in China by calculating dissimilarity as distance. Higher value signifies higher degree of dissimilarity between two cities. Cluster analysis is exploited to classify 50 cities into a number of different groups such that similar cities are placed in the same group. In addition, multidimensional scaling(MDS) technique can obtain visual representation for exploring the pattern of proximities among 50 major cities in China based on three development performance attributes. Research design, data, and methodology - This research is performed by the 2013 report provided with AliResearch in China(1/1/2013~11/30/2013) and utilized multivariate methods such as dissimilarity distance matrix, cluster analysis and MDS by using CLUSTER, KMEANS, PROXIMITIES and ALSCAL procedures in SPSS 21.0. Results - This research applies two types of cluster analysis and MDS on three development performances based on the 2013 report of Aliresearch. As a result, it is confirmed that grouping is possible by categorizing the types into four clusters which share similar characteristics. MDS is exploited to carry out positioning of both grouped locations of cluster and 50 major cities belonging to each cluster. Since all the values corresponding to Shenzhen, Guangzhou and Hangzhou(which belong to cluster 1 among 50 major cities) are very large, these cities are superior to other cities in all three evaluation attributes. Twelve cities(Beijing, ShangHai, Jinghua, ZhuHai, XiaMen, SuZhou, NanJing, DongWan, ZhangShan, JiaXing, NingBo and FoShan), which belong to cluster 3, are inferior to those of cluster 1 in terms of all three attributes, but they can be expected to be the next e-commerce revolution. The rest of major cities, in particular, which belong to cluster 4 are relatively inferior in all three attributes, so that this automatically evokes creative innovation, which leads to e-commerce development as a whole in China. In terms of internet businessman index, on the other hand, Tainan, Taizhong, and Gaoxiong(which belong to cluster 2) are situated superior to others. However, these three cities are inferior to others in an internet shopping index sense. The rest of major cities, in particular, which belong to cluster 4 are relatively inferior in all three evaluation attributes, so that this automatically evokes innovation and entrepreneurship, which leads to e-commerce development as a whole in China. Conclusions - This study suggests the implications to help e-governmental officers and companies make strategies in both Korea and China. This is expected to give some useful information in understanding the recent situation of e-commerce in China, by looking over development performances of 50 major cities. Therefore, we should develop marketing, branding and communication relevant to online Chinese consumers. One of these efforts will be incentives like loyalty points and coupons that can encourage consumers and building in-house logistics networks.