• 한국정밀공학회지
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• 제22권1호
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• pp.122-129
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• 2005

On the cluster system, the parallel code of rigid-plastic FEM has been developed. The cluster system, Simforge, has 15 processors and the total memory is 4.5GBytes. In the developed parallel code, the distributed data of the column-wise partitioned stiffness are stored as the compressed row storage and the diagonal preconditioned conjugate gradient solver is applied. The analysis of block upsetting is performed with the parallel code on Simforge cluster system. In this paper, the analysis results are compared and discussed.

• Journal of Multimedia Information System
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• 제4권4호
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• pp.189-194
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• 2017

In this study, we propose a method which is based on "Image segmentation by histogram thresholding using hierarchical cluster analysis"/HCA/ and "A nonparametric approach for histogram segmentation"/NHS/. HCA method uses that all histogram bins are one cluster then it reduces cluster numbers by using distance metric. Because this method has too many clusters, it is more computation. In order to eliminate disadvantages of "HCA" method, we used "NHS" method. NHS method finds all local minima of histogram. To reduce cluster number, we use NHS method which is fast. In our approach, we combine those two methods to eliminate disadvantages of Arifin method. The proposed method is not only less computational than "HCA" method because combined method has few clusters but also it uses local minima of histogram which is computed by "NHS".

• World Technopolis Review
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• 제8권2호
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• pp.104-119
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• 2019

Innovation clusters are essential in the economic development of many developed countries across the world. While they present ways for under-developed and developing countries to grow their economies, fully operational innovation clusters are yet to be established in Nigeria. Many experts argue that learning from experience is an effective way of galvanizing economic development. Therefore, in this study, an empirical analysis involving a multi-variable quantitative analysis was used to examine the factors that influence the performance of the Daedeok Innopolis Innovation Cluster (South Korea). The results obtained show that the investment in education, Research and Development (R&D), labor capacity of key players within the innovation cluster, and the transfer of technology (within the cluster) were essential factors that influence the performance of the Daedeok Innopolis Innovation Cluster.

• 반도체디스플레이기술학회지
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• 제15권2호
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• pp.20-25
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• 2016

The parallel computer cluster system has been known as the powerful tool to solve a complex physical phenomenon numerically. The numerical analysis of large size of Li-ion battery pack, which has a complex physical phenomenon, requires a large amount of computing time. In this study, the numerical analyses were conducted for comparing the computing efficiency between the single workstation and the parallel cluster system both with multicore CPUs'. The result shows that the parallel cluster system took the time 80 times faster than the single work station for the same battery pack model. The performance of cluster system was increased linearly with more CPU cores being increased.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.203-204
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• 2007

This paper investigated the influence on partial discharge distribution of various defects at the model power cable joints interface using K-means clustering. As the result of analyzing discharge number distribution of ${\Phi}-n$ cluster, clusters shifted to $0^{\circ}\;and\;180^{\circ}$ with increasing applying voltage. It was confirmed that discharge quantity and euclidean distance between centroids were increased with applying voltage from the analyzing centroid distribution of ${\Phi}-q$ cluster. The degree of dispersion was increased with calculating standard deviation of ${\Phi}-q$ cluster centroid. The tendency both number of discharge and mean value of ${\Phi}-q$ cluster centroid were some different with defect types.

• 대한환경공학회지
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• 제31권6호
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• pp.442-448
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• 2009

예혼합 분무화염의 유적군 연소 기구를 평가하기 위하여 레이저 가시화법, MICRO (multi-color integrated Cassegrain receiving optics) 및 PDA (phase Doppler anemometer) 광학계측 시스템을 이용하여 동시 시계열 계측을 실시하였다. 또한 유적군의 군연소수를 실험적으로 산출하여 이론해석에 적용하였을 경우 실제로 관찰되는 군연소 형태와 일치하는지에 대하여 검토하였다. 유적군 단면화상에 의해 확인된 모든 유적군에 대하여 실험적으로 군연소수 $G_c$를 산출한 결과 주로 내부 군연소와 외부 군연소로 분류되었으며 이론해석과 일치하였다. 또한 실제 관찰된 군연소 형태와 그 유적군의 군연소수를 이론해석에 적용한 경우에 군연소 형태가 일치하는 경우와 일치하지 않는 경우가 있었다. 일치하지 않는 원인은 군연소수를 유적의 기하학적 배치만으로 결정한 것이나 현상의 3차원성이 측정 결과에 영향을 미친 것이라고 생각되어진다.

• 한국항공우주학회지
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• 제31권5호
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• pp.37-43
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• 2003

전산유체역학분야에서의 효율적인 해석을 위해서 병렬처리기법이 널리 사용되고 있다. 병렬처리기법과 함께 최근에는 저가의 리눅스 클러스터 컴퓨터들이 기존의 슈퍼컴퓨터들을 대체하는 추세이다. 리눅스 클러스터 컴퓨터에서 수행되는 해석프로그램의 성능은 클러스터 시스템의 프로세서 성능 뿐 아니라 클러스터 시스템에서 사용되는 네트웍 장비의 성능에 크게 영향을 받는다. 본 연구에서는 미리넷2000, 기가비트 이더넷, 패스트 이더넷 등 네트웍 장비에 따라서 클러스터 시스템의 성능이 어떻게 달라지는지를 Netpipe, LINPACK, NAS NPB, 그리고 MIPNS2D Navier-Stokes 해석프로그램을 사용하여 비교하였다. 이러한 연구결과를 바탕으로 전산유체역학 분야에서 사용될 고성능 저비용 리눅스 클러스터 시스템을 구축하는 방법을 제시하고자 하였다.

• 응용통계연구
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• 제33권5호
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• pp.591-601
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• 2020

자기조직화지도는 고차원의 원자료를 노드들로 이루어진 저차원의 공간으로 투영하는 비지도학습 방법이다. 이 방법은 고차원의 자료를 노드들을 사용하여 2 또는 3차원의 공간에서 시각화할 수 있고, 이를 통해 자료의 특성을 탐색하는데 유용하다. 자료의 구조를 파악하기 위해 종종 노드들에 대한 군집분석을 시도하는데, 군집분석의 중요한 문제중 하나는 군집의 개수를 결정하는 것이다. 이 문제를 해결하기 위해 다양한 군집타당성지수들이 지금까지 개발되어 왔고, 이러한 지수들은 자기조직화지도의 노드들의 군집분석에 직접적으로 적용될 수 있다. 그러나, 자기조직화 지도가 원자료의 위상적 특성을 저차원 공간에 반영할 수 있다는 특징을 갖는데 반해, 이러한 일반적인 지수들은 이를 고려하지 않는 문제가 있다. 이에 본 연구에서는 원자료의 위상적 특성을 고려한 노드들 사이의 연결강도를 기반으로 하는 군집타당성지수를 제안한다. 이 새로운 군집타당성지수의 성능은 모의실험을 통해 기존의 군집타당성지수들과의 비교되고 검증된다.

• 융합경영연구
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• 제6권4호
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• pp.17-27
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• 2018

Purpose - As Korea is reaching a post-aged society, the number of chronic illness is increasing, and the demand for rehabilitation medical device is growing. Although there is high potential for the growth in rehabilitation industry, because most of the related companies in Korea are relatively small, lacking capital or R&D resource, it is difficult for them to create an innovative product, and currently most of the high-tech equipments are imported. Therefore a medical device cluster, where business, research, medical institutes and universities may work cooperatively to enhance research development and solve issues is necessary for future development. Research design, data, methodology - In this method we have done a literature review of the rehabilitation industry and industrial cluster. Based on the studies, we have conducted an exploratory factor analysis by studying examples of foreign and domestic medical clusters and drawing success factors in forming a medical cluster. Next based on the studies we have conducted a survey to domestic medical device companies to find their difficulties and needs to form a successful medical device cluster. Results - This paper provides both theoretic review on success factors of forming a medical device cluster and practical analysis using case study and survey. Conclusion - The significance of this paper is that based on the literature review, we have compared actual examples of domestic/foreign medical clusters and drawn difference and coincidence between literature and actual cluster success factor. We were also able to conduct a survey on actual medical device companies and through the results we were able to search difficulties and necessities of medical device companies.

• 한국환경과학회지
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• 제13권3호
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• pp.233-244
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• 2004

This study was conducted to evaluate water quality in the Mankyung River using multivariate analysis. The analysis data which was surveyed from January 1996 to December 2002 in Mankyung river was aquired by the ministry of environment. Twelve water quality parameters were determined on each survey. The results were summarized as follow; Water quality in the Mankyung River could be explained up to 74.90% by four factors which were included in loading of organic matter and nutrients by the tributaries(43.28%), seasonal variation(10.40%), loading of pathogenic bacteria by domestic sewage of Gapcheon (12.41%) and internal metabolism in river(8.81%). The result of cluster analysis by station was classified into three group that has different water quality characteristics. Especially, Iksan river was appeared to considerable water quality characteristics against other station. In monthly cluster analysis, three group was classified by seasonal characteristics. Also, in yearly cluster analysis, three group was classified. It is necessary to control the pollutant loadings by domestic sewage and livestock waste for water quality management of Mankyung river.