• 한국연초학회지
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• 제4권1호
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• pp.37-42
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• 1982

Korean local and introduced varieties were classified by the cluster analysis of correlation and taxonomic distance based on nineteen growth characters. 1. Thirty six varieties can be classified into three groups(I, II, III) by WVGM (weighted variable group method) 2. Major characters for classifying cultivars were days to flowering, number of leaves, leaf length, stem diameter and width of midrib: the five characters seemed to be useful in monothetic classification. 3. Korean varieties were similar to oriental, and japanese varieties to taiwan. 4. WVGM was more accurate and meaningful than classification by WPGM (weighted paired group method) and reticulate diagram of correlation. 5. Characteristics of each group: Group I closely related to many leaves, late of maturity and broad leaf type, Group II related to medium leaves, late of maturity and narrow leaf type, Croup 19 related to few leaves, early of maturity and medium leaf type respectively.

• 한국멀티미디어학회논문지
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• 제17권10호
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• pp.1160-1170
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• 2014

Clustering methods are very useful in many fields such as data mining, classification, and object recognition. Both the supervised and unsupervised grouping approaches can classify a series of sample data with a predefined or automatically assigned cluster number. However, there is no constraint on the number of elements for each cluster. Numbers of cluster members for each cluster obtained from clustering schemes are usually random. Thus, some clusters possess a large number of elements whereas others only have a few members. In some areas such as logistics management, a fixed number of members are preferred for each cluster or logistic center. Consequently, it is necessary to design a clustering method that can automatically adjust the number of group elements. In this paper, a k-means based clustering method with a fixed number of cluster members is proposed. In the proposed method, first, the data samples are clustered using the k-means algorithm. Then, the number of group elements is adjusted by employing a greedy strategy. Experimental results demonstrate that the proposed clustering scheme can classify data samples efficiently for a fixed number of cluster members.

• 상하수도학회지
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• 제21권2호
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• pp.165-175
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• 2007

Performance indicators haven't been used for the assessment of the wastewater treatment facility or management in Korea yet, therefore they are going to be important parts in wastewater utilities because they are used to understand present situation and to compare one with other wastewater utilities. In this study, we used performance indicators to assess the condition of wastewater utilities and they were divided into four categories (A, B, C, and D). A category represented the condition of the planning & construction and composed of wastewater supply, disaster defence and employees. B category represented maintenance of wastewater utilities and were composed of manhole, sewer, and technical employees. C category showed the operation efficiency of wastewater utilities and D category represented the environmental load. To analyze the situation of wastewater utilities overall, cluster analysis was performed using four categori' es indicators. And CCC (Cubic Clustering Criterion) and R-square were used to decide the proper number of clusters, and wastewater utilities of 48 cities were divided into 5 groups(I, II, III, IV, and V groups). Each cluster was analyzed by average and standard deviation to understand the situation of wastewater utilities. A group analysis showed that IV and V clusters were insufficient, B group showed that I and IV groups were insufficient, C group showed all clusters are above average, and D group was also like C group.

• Bulletin of the Korean Chemical Society
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• 제27권1호
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• pp.35-36
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• 2006

• 미생물학회지
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• 제26권3호
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• pp.247-255
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• 1988

수리학적 방법을 이용하여 낙동강 하구에서 분리한 종속영양세균을 분류하였다. 70%의 유사도로 나눈 결과, 정점 l에서 분 리한 균주는 14 clusters로, 정점 2에서 분리한 균주는 17 clusters로, 정정 3에서 분리한 균주는 17 clusters로, 정점 4에서 분리한 균주는 15 clusters로 구분되었다. 각 cluster의 주요 생리학적 및 형태학적 특성으로 분류한 결과, 정점 1에서의 우점 종은 AeroηlOnas, Vibrio, Alcaligenes로, 정점 2에서는 Alcaligenes로, 정점 3에서는 Aeromonas, Vibrio, Moraxell $\alpha$-Acinetobacter group으로, 정점 4에서는 Pseudomonas로 판명되었다.

• The Korean Journal of Ecology
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• 제23권6호
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• pp.453-460
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• 2000

The forest vegetation of Mt. seondal was classified into eight communities and one afforestation by the phytosocialogical method (Z-M method). In general, Quercus mongolica trees occupied most of the area, while afforestation forest was distributed on the lower slope, cultivated land, and at the vicinity of village. The vegetation on the top part of Mt. Seondal was comparatively well preserved, but that in the lower areas has been disturbed heavily by human activity and some had mixed forests composed of pine trees, oaks, ashes, and Rhododendron micrantum shrub. By cluster analysis method. nine groups were identified as follows : Quercus mongolica group, Q. mongolica - Pinus densiflora group, Q. mongolica - Rhododendron schlipen - bachii group, Q. mongolica - Symplocos chinensis for. pilosa group, P. densiflora group, Juglans mandshurica group, Fraxinus mandshurica group, Betula costata group and Larix leptolepis group. These groups showed differences in species composition, but Quercus mongolica, Q. mongolica - P. densiflora, Q. mongolica - R. schlippenbachii and Q. mongolica - S. chinensis for. pilosa groups among them showed very similar floristic composition to each other. In the relationship between polar ordination axes and environmental variables, altitude was the environmental factor determining variation in species composition along axis X and soil moisture was the environmental along axis Y. They were the main factors in determining forest vegetation. The result of cluster analysis and polar ordination for the forest vegetation were corresponded to those of phytosocialogical classification in classifying vegetation.

• 한국학교ㆍ지역보건교육학회지
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• 제21권1호
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• pp.75-89
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• 2020

Objects: The purpose of this study was to examine the differences of college students' big-five personality factors, academic adaptation, and psychological well-being according to cluster types based on the grit. Methods: The participants of this study were 190 college students. All variables were evaluated by self-report of college students. The data were analyzed by one-way ANOVA and two-step clustering statistics using SPSS 21.0. Results: First, a cluster analysis on a sample of 190 college students revealed four clusters: the more highly grit group, higher tenacity group, higher consistency of interests, and the less grit group. Second, there were significant differences of 190 college students' big five personality factors, academic adaptation, and psychological well-being according to cluster types based on the grit. Conclusions: These findings can be used as an important contribution to further research and educational practices for promoting the grit in college students. Also it suggests the need for health education to increase the psychological well-being of college students.

• IEIE Transactions on Smart Processing and Computing
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• 제4권2호
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• pp.115-125
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• 2015

This paper presents a Cuckoo search algorithm to secure adversaries misdirecting multi-hop routing in Mobile ad hoc networks (MANETs) using a robust Trust Predicated Routing Framework with an optimized cluster head selection. The clustering technique designed in this framework leads to efficient routing in MANETs. The heavy work load in the node causes an energy drop in cluster head, which leads to re-clustering of the group, and another cluster head is selected to avoid packet loss during data transmission. The problem in the re-clustering process is that the overall efficiency of the routing process is reduced and the processing time is increased. A Cuckoo search based optimization algorithm is proposed to solve the problem of re-clustering by selecting the secondary cluster head within the initially formed cluster group and eliminating the reclustering process. The proposed framework enables a node to select a reliable and secure route for MANET and the performance can be evaluated by comparing the simulated results with the AODV routing protocol, which shows that the performance of the proposed routing protocol are improved significantly.

• 대한기계학회논문집B
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• 제27권8호
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• pp.1191-1199
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• 2003

This paper describes to observe the combustion process of only one droplet cluster. In this study, liquid fuel was atomized by ultrasonic wave to form an acoustically levitated droplet cluster. In order to elucidate the detailed structure of burning process of the droplet cluster, laser tomography method was applied. Time-series planar images of fuel droplets were processed and diameter of the each droplet was calculated based on the Mie-scattering theory. Using these data, the modified droplet group combustion number was estimated in time-series. As the result, when the internal droplet group combustion occur, the modified group combustion number dose not decrease monotonically, but show a tow-staged decreasing process. In all case of combustion process, combustion reactions were measured two types that combustion speed was fast and slow. It was casued by difference of concentration degree and droplet size distribution.

• Journal of information and communication convergence engineering
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• 제8권5호
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• pp.549-553
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• 2010

Lim et al. proposed a Hybrid Group Key Management scheme for Hierarchical Self-Organizing Sensor Network in 2008 to provide a secure way to pass down the group key for cluster-based communication. This paper presents two practical attacks on the scheme proposed by Lim et al. by tampering sensor nodes of a cluster to recover necessary secret keys and by exploiting the IDS employed by the scheme. The first attack enables a long-term but slow data fabrication while other attack causes more severe DoS on the access to cluster sensor nodes.