• 한국산학기술학회논문지
• /
• 제11권12호
• /
• pp.4991-4996
• /
• 2010

무선 센서 네트워크에서 클러스터링 기법은 클러스터를 형성하여 데이터를 통합한 후 한 번에 전송해서 에너지를 효율적으로 사용하는 기법이다. 클러스터 그룹 모델은 클러스터링에 기반을 두지만 이전의 기법과 달리 클러스터 헤드에 집중된 에너지 과부하를 클러스터 그룹 헤드와 클러스터 헤드로 분산시켜서 전체 에너지 소모량을 줄인다. 본 논문에서는 이러한 클러스터 그룹 모델에서 에너지 소모 모델의 임계값에 따라 최적의 클러스터 그룹 수와 클러스터 수를 구하고 이를 이용하여 센서 네트워크 전체 에너지 소모량을 최소화하고 네트워크 수명을 최대화한다. 실험을 통하여 제안된 클러스터 그룹 모델이 이전의 클러스터링 기법보다 네트워크 에너지 효율이 향상되었음을 보였다.

• 가정과삶의질연구
• /
• 제30권6호
• /
• pp.151-166
• /
• 2012

The major findings are(were) as follows: 1) The Eco-friendly consumption behavior was divided into three(3) clusters, namely "The Middle Group" of eco-friendly consumption behavior(cluster I), "The Inferior group" of eco-friendly consumption behavior(cluster II), and "The Excellent Group" of eco-friendly consumption behavior(cluster III). 2) The differences in the general characteristics among the three clusters were founded on the experience of green consumption information and sources of information. 3) The characteristics of cluster I(The Middle Group) were(are) found to be eco-conscious, and aware of the consequences of behaviors, green market conditions and environmental issues. This cluster was the middle-average group. The characteristics of cluster III(The Excellent Group) were(are) found to have the willingness to pay additional costs, being aware of the social norms of the reference group, having an awareness of eco-institutional conditions, being knowledgeable about environmental policy, and finally, being personally involved in green consumption behavior. This cluster was the high-average group, whereas cluster II(The Inferior Group) was the low-average group.

• 한국의류학회지
• /
• 제10권3호
• /
• pp.37-48
• /
• 1986

The purpose of this study was to analyze 'the natural groupings' of subjects in order to classify highly similar somatotype for clothing construction. The sample for the study was drawn randomly out of senior high school boys in Seoul urban area. The sample size was 425 boys between age 16 and 18. Cluster analysis was more concerned with finding the hierarchical structure of subjects by three dimensional distance of stature. bust girth and sleeve length. The groups forming a partition can be subdivided into 5 and 6 sets by the hierarchical tree of the given subjects. Ward's Minimum Variance Method was applied after extraction of distance matrix by the Standardized Euclidean Distance. All of the above data was analyzed by the computer installed at Korea Advanced Institute of Science and Technology. The major findings, take for instance, of 16 age group can be summarized as follows. The results of cluster analysis of this study: 1. Cluster 1 (32 persons means $18.29\%$ of the total) is characterized with smaller bust girth than that of cluster 5, but stature and sleeve length of the cluster 1 are the largest group. 2. Cluster 2 (18 Persons means $10.29\%$ of the total) is characterized with the group of the smallest stature and sleeve length, but bust girth larger than that of cluster 3. 3. Cluster 3(35persons means $20\%$ of the total) is classified with the smallest group of all the stature, bust girth and sleeve length. 4. Cluster 4(60 persons means $34.29\%$ of the total) is grouped with the same value of sleeve length with the mean value of 16 age group, but the stature and bust girth is smaller than the mean value of this age group. 5. Cluster 5(30 persons means $17.14\%$ of the total) is characterized with smaller stature than that of cluster 1, and with larger bust girth than that of cluster 1, but with the same value of the sleeve length with the mean value of the 16 age group.

• 정보처리학회논문지A
• /
• 제8A권3호
• /
• pp.261-268
• /
• 2001

With the rapid growth of the Internet, various web-based businesses are creating a new environment in an imaginary space. However, this expanding Internet and user increase cause an overflow of transmission and numerous subordinate problems. To solve these problems, a parallel cluster system is produced using different methods. This thesis recommends a multi0distribution cluster group. It constructs a MPP dynamic distribution sub-cluster group using numerous low-priced and low-speed systems. This constructed sub-cluster group is then connected with a singular virtual IP to finally serve the needs of clients (users). This multi-distribution cluster group consists of an upper structure based on LVS and a dynamic serve cluster group centered around an SC-server. It conducts the workloads required from users in a parallel process. In addition to the web service, this multi-distribution cluster group can efficiently be utilized for the calculations which require database controls and a great number of parallel calculations as well as additional controls with result from the congestion of service.

• 한국의류학회지
• /
• 제18권2호
• /
• pp.211-220
• /
• 1994

The purpose of this study was to analyze the foot type by cluster analysis for footwear. The sample size for the study was 200 college womens between age 19 and 23 in Pusan urban area. There were measured 17 items of the foot for factor analysis and cluster analysis. The result was as follows : 1. 1'here were 9 items selected by factor analysis. 2.'rho cluster analysis of the foot must be analyzed by direct and indirect measurement indivisually. 3. The cluster analysis of the direct measurement ; Cluster 1 : 1'he foot length is all much the same to mean value of this age group and the items of width and circumference are relatively small to other clusters. Cluster 2 ; The foot length is relatively small to other clusters and the items of width and circumference are all much the same to mean value of this age group. Cluster 3 ; The foot sine Is relatively large to other clusters. 4. The cluster analysis of indirect measurement ; Cluster 1 ; The (cot print angle is high find Metatarso-Phalanx angle is transformed Cluster 2 ; The foot print angle is low and Melatarso-Phalanx angle is normal. Cluster 3 : Tho foot print angle Is middle and Metatarso-Phalanx angle is all the mush same to mean value of this age group. Cluster 4 . The foot print angle Is the most value and Metatarso-Phalanx angle is normal.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제7권8호
• /
• pp.2042-2060
• /
• 2013

In wireless sensor networks (WSNs), energy efficiency is one of the most essential design considerations, since sensor nodes are resource constrained. Group communication can reduce WSNs communication overhead by sending a message to multiple nodes in one packet. In this paper, in order to simultaneously resolve the transmission security and scalability in WSNs group communications, we propose a hierarchical cluster-based secure and scalable group key management scheme, called HRKT, based on logic key tree and route key tree structure. The HRKT scheme divides the group key into cluster head key and cluster key. The cluster head generates a route key tree according to the route topology of the cluster. This hierarchical key structure facilitates local secure communications taking advantage of the fact that the nodes at a contiguous place usually communicate with each other more frequently. In HRKT scheme, the key updates are confined in a cluster, so the cost of the key updates is reduced efficiently, especially in the case of massive membership changes. The security analysis shows that the HRKT scheme meets the requirements of group communication. In addition, performance simulation results also demonstrate its efficiency in terms of low storage and flexibility when membership changes massively.

• Journal of Microbiology and Biotechnology
• /
• 제17권6호
• /
• pp.919-927
• /
• 2007

Antagonistic fluorescent pseudomonads isolated from rhizospheric soil of rice were characterized by 16S rRNA amplicon and fatty acid methyl ester (FAME) analyses. Antagonistic isolates were grown in the fermentation media, and production of antibiotics was confirmed by thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC). Production of fungal cell-wall-degrading enzymes such as protease, cellulase, pectinase, and chitinase was determined. Dendrogram based on the major and differentiating fatty acids resulted into 5 clusters, viz., cluster I (P. pseudoalcaligenes group), cluster II (P. plecoglossicida group), cluster III (P. fluorescens group), cluster IV (P. aeruginosa group), and cluster V (P. putida group). Characteristic presence of high relative proportions of cyclopropane (17:0 CYCLO w7c) was observed in antagonistic bacteria. Data revealed biodiversity among antagonistic fluorescent pseudomonads associated with the rice rhizosphere. Results presented in this study will help to identify the antagonistic isolates and to determine their mechanisms that mediate antagonism against fungal pathogens of rice.

• 한국통신학회논문지
• /
• 제38C권11호
• /
• pp.1060-1073
• /
• 2013

본 논문에서는 무선 애드혹 네트워크상에서 그룹 이동성이 있는 모바일 사용자들을 beacon 메시지 수신 상태 정보만을 이용하여 분산적인 방법으로 온라인 클러스터링 하는 기법과 그룹 내로 데이터를 효과적으로 전달하기 위한 클러스터 헤드 노드를 선정하는 기법을 제시하고, 선정한 클러스터 헤드 노드를 통해 그룹 내부로 데이터를 전달할 수 있는 효율적인 그룹 라우팅 기법을 제안한다. ns-2를 이용하여 518개의 정적 노드와 20개의 동적 노드로 구성된 네트워크에 대해 성능 평가한 결과, 평균적으로 96 %의 높은 클러스터링 정확도를 보임을 확인할 수 있었다. 또한 그룹의 개념 없이 개별적으로 모바일 노드들로 일대일 라우팅을 한 경우에 비해 제안한 클러스터 기반 라우팅 기법을 사용했을 경우, 총 라우팅 비용이 1/20 정도로 감소하였으며, 그룹의 개념은 존재하지만 임의의 모바일 노드를 통해 intra-cluster 라우팅 했을 경우에 비해, 제안한 클러스터 헤드 노드를 통해 라우팅 했을 경우, 라우팅 비용이 평균적으로 1/2 정도로 감소함을 확인할 수 있었다.

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

• 한국정보과학회논문지:시스템및이론
• /
• 제30권10호
• /
• pp.533-543
• /
• 2003

클러스터에 대한 관심이 증가함에 따라 클러스터의 고가용성(high availability)을 보장하기 위한 그룹 통신 시스템의 연구가 활발하다. 하지만 클러스터를 이용한 커널 수준 응용 프로그램 개발에 활용할 수 있는 커널 수준의 그룹 통신 시스템은 전무하며, 기존에 개발되어 있는 사용자 수준 그룹 통신시스템을 그대로 커널 수준에서 사용하는 것은 무리가 있다. 본 논문에서는 클러스터의 고 가용성 보장을 위하여 리눅스 커널 상에서 구현된 그룹 통신 시스템인 KCGCS(Kernel-level Cluster Group Communication System)를 설계하고 구현하였다. KCGCS는 기존 사용자 수준의 시스템들과는 달리 경량(light weight)의 핫빗(heartbeat) 메시지와 링(ring) 구조의 핫빗 메커니즘을 사용하여 확장성 있는 장애 상황 발견 메커니즘을 구현하였다. 또한 멤버쉽 관리 측면에서 KCGCS는 중앙 집중된 기존의 방법과는 달리 분산된 코디네이터를 사용하여 신뢰성을 향상시켰다.