• 한국정보과학회논문지:시스템및이론
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• 제30권5_6호
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• pp.290-298
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• 2003

인터넷 기반 시스템에서는 고가용도와 고성능을 제공해야하며, 클러스터 시스템 기술은 이에 대한 하나의 해결책으로 떠오르고 있다. 클러스터 시스템을 사용하는 중요한 목적은 성능과 가용도의 확보에 있으며, 고가용도 클러스터 시스템은 구성 노드들 중 일부에 결함이 발생했을 때 이를 비용ㆍ효율적으로 해결한다. 본 논문은 (n,k) 클러스터 시스템의 성능을 고려한 가용도 개선과 손실비용 분석에 관한 연구로 소프트웨어 재활 기법을 적용한 (n,k) 클러스터 시스템의 가용도 모델을 제안하였으며, 고가용도가 요청되는 시스템에서 소프트웨어 재활은 가용도 향상을 가져오는 유용한 기법 중의 하나임을 파악하였다.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2010년도 한국우주과학회보 제19권1호
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• pp.34.4-34.4
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• 2010

We present the properties of globular cluster systems for 10 early-type galaxies in low density environments obtained using deep images from the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope (HST). Using the ACS Virgo Cluster Survey as a counterpart in high-density environments, we investigate the role of environment in determining the properties of their globular cluster systems. We detect a strong colour bimodality of globular cluster systems in half of our galaxy sample. It is found that there is a strong correlation between the colour and richness of globular cluster populations and their host galaxy luminosities: the less bright galaxies possess bluer and fewer globular clusters as also seen in rich cluster environments. However, the mean colour of globular clusters in our field sample are slightly bluer than those in cluster environments at a given galaxy luminosity, and the colour of the red population has a steeper slope with absolute luminosity. By employing the YEPS simple stellar population model, the colour offset corresponds to metallicity difference of $\Delta$[F e/H ] ~ 0.15 - 1.20 or an age difference of $\Delta$age ~ 2 Gyr on average, implying that GCs in field galaxies appear to be either less metal-rich or younger than those in cluster galaxies. Although we have found that galaxy environment has a subtle effect on the formation and metal enrichment of GC systems, host galaxy mass is the primary factor that determines the stellar populations of GCs and the galaxy itself.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제10권5호
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• pp.385-393
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• 2004

현재 클러스터 시스템은 여러 분야의 문제들을 위하여 폭 넓게 이용되어지고 있으며 유용한 고성능 컴퓨팅 자원으로 인식되고 있다. 클러스터 시스템의 사용자가 늘어남에 따라 클러스터 시스템의 성능 개선 못지 않게 안정적인 운영을 유지하는 것도 중요한 상황이다. 하드웨어 예방 정비가 정상 운영을 위해서 중요한 것임에도 불구하고, 예방 점검 시간에 일반적인 클러스터 시스템을 위하여 사용될 수 있는 검사 도구는 주요 관심사가 되지 못했다. 본 논문에서는 하드웨어 예방 정비를 고려하여 클러스터 시스템을 위한 하드웨어 검사 도구를 제안한다. CTS(Cluster system Test Suite)로 명명된 클러스터 시스템 검사 도구는 메모리와 NIC를 점검하기 위한 두개의 검사 루틴을 가지고 있다. CTS를 설계시, CTS가 일반 적인 클러스터 시스템이 가지는 공통된 특징을 지원하도록 노력하였으며 검사 조건 설정에서 결과 조회까지 모든 작업은 통합 GUI 환경에서 진행될 수 있도록 하였다. 두 종류의 클러스터 시스템을 점검할 때, CTS를 사용하였고 클러스터 시스템을 관리하는데 유용한 정보가 제공됨을 확인하였다.

• 한국정보시스템학회지:정보시스템연구
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• 제17권3호
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• pp.135-152
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• 2008

Basically within a special regional area, a regional cluster seems to be based on core competencies of individual intra-cluster companies and collaboration among them. Information infrastructure has been emphasized as on one of competitive factors of a regional cluster, and it can be organized using collaboration system architecture integrated with each company's internal systems for efficient supply chain operation. As one of technical methods to prepare the system infrastructure supporting the collaboration of companies in a regional cluster, the Web Services can be effectively used. In this paper, a collaborative information system infrastructure for a regional cluster is suggested within the scope of supply chain management. And the efficiency of the proposed alternative is appraised with the features of a regional cluster.

• 한국지능시스템학회논문지
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• 제9권6호
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• pp.621-626
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• 1999

In this paper a new cluster validation index which is heuristic but able to eliminate the monotonically decreasing tendency occurring in which the number of cluster c gets very large and close to the number of data points n is proposed. We review the FCM algorithm and some conventional cluster validity criteria discuss on the limiting behavior of the proposed validity index and provide some numerical examples showing the effectiveness of the proposed cluster validity index.

• 제어로봇시스템학회논문지
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• 제13권9호
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• pp.920-926
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• 2007

Establishing a fixed path for the message delivery through a wireless network is impossible due to the mobility. Among the number of routing protocols that have been proposed for wireless ad-hoc networks, the AODV(Ad-hoc On-demand Distance Vector) algorithm is suitable in the case of highly dynamic topology changes, along with ZigBee Routing(ZBR), with the exception of route maintenance. Accordingly, this paper introduces a routing scheme focusing on the energy efficiency and route discovery time for wireless alarm systems using IEEE 802.15.4-based ZigBee. Essentially, the proposed routing algorithm utilizes a cluster structure and applies ZBR within a cluster and DSR (Dynamic Source Routing) between clusters. The proposed algorithm does not require a routing table for the cluster heads, as the inter-cluster routing is performed using DSR. The performance of the proposed algorithm is evaluated and compared with ZBR using an NS2 simulator. The results confirm that the proposed Cluster-based AODV (CAODV) algorithm is more efficient than ZBR in terms of the route discovery time and energy consumption.

• International Journal of Computer Science & Network Security
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• 제23권1호
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• pp.11-16
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• 2023

Vehicular networks are part of the next generation wireless and smart Intelligent Transportation Systems (ITS). In the future, autonomous vehicles will be an integral part of ITS and will provide safe and reliable traveling features to the users. The reliability and security of data transmission in vehicular networks has been a challenging task. To manage data transmission in vehicular networks, road networks are divided into clusters and a cluster head is selected to handle the data. The selection of cluster heads is a challenge as vehicles are mobile and their connectivity is dynamically changing. In this paper, a novel secure cluster head selection algorithm is proposed for secure and reliable data sharing. The idea is to use the secrecy rate of each vehicle in the cluster and adaptively select the most secure vehicle as the cluster head. Simulation results show that the proposed scheme improves the reliability and security of the transmission significantly.

• 산업경영시스템학회지
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• 제36권1호
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• pp.24-35
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• 2013

A cell formation approach based on cluster analysis is developed for the configuration of manufacturing cells. Cell formation, which is to group machines and parts into machine cells and the associated part families, is implemented to add the flexibility and efficiency to manufacturing systems. In order to develop an efficient clustering procedure, this paper proposes a cluster analysis-based approach developed by incorporating and modifying two cluster analysis methods, a hierarchical clustering and a non-hierarchical clustering method. The objective of the proposed approach is to minimize intercellular movements and maximize the machine utilization within clusters. The proposed approach is tested on the cell formation problems and is compared with other well-known methodologies available in the literature. The result shows that the proposed approach is efficient enough to yield a good quality solution no matter what the difficulty of data sets is, ill or well-structured.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제12권1호
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• pp.21-30
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• 2006

최근 컴퓨터에 의해 처리되어야 할 정보의 양이 급증하면서, 이의 처리를 위해 여러 개의 단일 서버를 고속의 네트워크(network)으로 연결한 클러스터 컴퓨팅 시스템 (cluster computing system)이 등장하게 되었다. 그 결과, 클러스터 기반 DBMS에 관한 연구가 국내외적으로 활발히 진행 중이며, 이에 따라 클러스터 기반 DBMS를 모니터링 및 관리하는 클러스터 관리기의 개발이 요구된다. 그러나, 클러스터기반 DBMS를 효율적으로 관리할 수 있는 관리 도구에 대한 연구는 미흡한 실정이다. 따라서 본 논문에서는 클러스터 기반 DBMS를 위한 고가용성 클러스터 관리기를 설계 및 구현한다. 구현된 클러스터 관리기는 그래픽 사용자 인터페이스(GUI)를 통해, 클러스터 시스템 내의 노드의 상태 및 각 노드에서의 DBMS 상태를 모니터(monitor)한다. 아울러, 각 서버의 상태를 모니터한 정보를 바탕으로, 서버의 오류를 감지하고 복구함으로써 클러스터 기반 DBMS의 고가용성을 지원한다.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2003년도 ISIS 2003
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• pp.330-333
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• 2003

Initial cluster size for clustering of partitioning methods is very important to the clustering result. In K-means algorithm, the result of cluster analysis becomes different with optimal cluster size K. Usually, the initial cluster size is determined by prior and subjective information. Sometimes this may not be optimal. Now, more objective method is needed to solve this problem. In our research, we propose a hybrid genetic algorithm, a tree induction based evolution algorithm, for determination of optimal cluster size. Initial population of this algorithm is determined by the number of terminal nodes of tree induction. From the initial population based on decision tree, our optimal cluster size is generated. The fitness function of ours is defined an inverse of dissimilarity measure. And the bagging approach is used for saying computational time cost.