• Journal of the Korea Society of Computer and Information
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• v.19 no.11
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• pp.1-7
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• 2014

In this paper, we propose a virtual machine(VM) remapping scheme that reduces VM relocation time on a cloud cluster. The proposed scheme finds VMs that should be migrated in sequence from a given VM map, and exchanges destinations of some VMs among them to reduce the VM relocation time. The VMs, the destinations of which will be exchanged, are chosen based on the amount of physical machine's available resources and migration completion time. The exchange of destinations is repeated until the VM relocation time cannot be shortened any further. Through a simulation, we show that the proposed scheme reduces VM relocation time by 42.7% in maximum.

• Journal of Internet Computing and Services
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• v.6 no.2
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• pp.69-84
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• 2005

As the Internet users are increasing rapidly, a cluster web server system is attracted by many researchers and Internet service providers. The cluster web server has been developed to efficiently support a larger number of users as well as to provide high scalable and available system. In order to provide the high performance in the cluster web server, efficient load distribution is important, and recently many content-aware request distribution techniques have been proposed. In this paper, we propose a new content-aware load balancing technique that can evenly distribute the workload to each node in the cluster web server. The proposed technique is based on the hash histogram transformation, in which each URL entry of the web log file is hashed, and the access frequency and file size are accumulated as a histogram. Each user request is assigned into a node by mapping of (hashed value-server node) in the histogram transformation. In the proposed technique, the histogram is updated periodically and then the even distribution of user requests can be maintained continuously. In addition to the load balancing, our technique can exploit the cache effect to improve the performance. The simulation results show that the performance of our technique is quite better than that of the traditional round-robin method and we can improve the performance more than $10\%$ compared with the existing workload-aware load balancing(WARD) method.

• Proceedings of the Korea Information Processing Society Conference
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• 2004.05a
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• pp.15-18
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• 2004

XML 검색을 위한 기존의 비트맵 인덱싱은 XML을 문서, 경로, 단어로 구성된 3차원 비트맵 인덱스에 매핑하고 이를 이용해 정보를 추출함으로써 뛰어난 성능을 입증하였다. 그러나 이것은 유사 문서를 수집하고 검색하기 위해 경로 전체를 인덱스 구성의 단위로 사용함으로써 유사 경로를 인식하지 못하는 문제를 초래하였으며 유사 경로를 인식하지 못함으로 인해 유사 문서 검색의 치명적인 성능 저하가 발생하게 되었다. 이에 따라 본 논문에서는 기존의 XML 검색을 위한 비트맵 인덱싱이 유사 경로를 인식하지 못하는 문제점을 해결하기 위해 유사 경로 탐색을 위한 새로운 비트맵 인덱스를 설계하고 이를 통해 효과적으로 유사 문서를 검색할 수 있는 기법을 제안한다. 제안된 기법은 노드들을 단위로 하는 새로운 비트맵 인덱스를 구성하고 구성된 인덱스의 중심을 통해 유사 경로 탐색을 위한 클러스터들을 선별적으로 검색한다. 그리고 유사 경로 탐색을 통해 추출된 경로들을 유사 문서 검색에 활용함으로써 비트맵 인덱싱의 빠른 성능을 그대로 유지하면서 기존의 XML 검색을 위한 비트맵 인덱싱이 유사 경로를 인식하지 못함으로써 발생하는 유사 문서 탐색의 성능 저하를 효과적으로 해결한다.

• Journal of KIISE:Computer Systems and Theory
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• v.34 no.9
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• pp.407-415
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• 2007

In parallel cluster computing systems, the efficiency of communication between computing nodes is one of important factors that decide overall system performance. Accordingly, many researchers have studied on high-performance inter-node communication. The recently launched multi-core processor, however. increases the importance of intra-node communication as well because the more the number of cores in a node, the more the number of parallel processes running in the same node. Though there have been studies on intra-node communications, these have limited considerations on the state-of-the-art systems. In this paper, we propose a Linux kernel module that minimizes the number of data copy by exploiting the memory mapping mechanism for high-performance intra-node communication. The proposed kernel module supports the Linux kernel version 2.6. The performance measurements over a multi-core system present that the proposed kernel module can achieve lower latency up to 62% and higher throughput up to 144% than an existing kernel module approach. In addition, the measurements reveal that the performance of intra-node communication can vary significantly based on whether the cores that run the communication processes are belong to the same processor package (i.e., sharing the L2 cache).

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.29 no.5
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• pp.479-485
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• 2011

A number of case studies that find distribution of longevity population and influencing factors through the spatial data fusion using GIS techniques are growing. The majority cases of these studies are adopt census administrative boundary data for the spatial analysis. However, these methods cannot fully explain the phenomenon of longevity because there are a variety of spatial characteristics within the census administrative boundaries. Therefore, studies of spatial unit are required that realistically reflect the phenomenon of human longevity. The dasymetric mapping method enables to product of spatial unit more realistic than census administrative boundary map and statistic estimates of small area utilizing diversity spatial information. In this study, elderly population of small area has been estimated within statistically significant level that applied the vector based dasymetric mapping method. Also, the cluster analysis confirmed that the variation of local spatial relationship within census administrative boundary. The result of this study implied that the need for local-level studies of the human longevity and the validity of the dashmetric mapping techniques.

• Journal of the Economic Geographical Society of Korea
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• v.10 no.3
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• pp.332-343
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• 2007

It is not so long that the cultural industrial sector has been noted as one of the major engines of regional economy in Korea. In parallel with balanced development strategies recently emphasized in the Korean regional policy, there has been a wide range of investment to formulate cultural industrial districts in major cities. This trend of investment focus has changed the development strategies of each city. There are criticisms, however, to this public sector-dominated nurturing of cultural economy. This paper overviews the recent policy of cultural industrial districts in Korea, in terms of its background, institutional basis, performances, and some evaluations. Some suggestions are provided in order to make the policy successful; emphasize developing the culture industry itself, develop clusters specifically focused on the characteristics of the culture industry, deliberate substantial measures for nurturing companies and human resources in the local regions, and formulate a system in which the local dominates and the center supports.

• Journal of the Korean Society for information Management
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• v.25 no.2
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• pp.157-166
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• 2008

In this study, pathfinder network analysis has been carried out to identify subject domains of documents which cited articles in the ASIST Proceedings. This represents how articles in the ASIST Proceedings are flowed and used in what subjects areas. For this analysis, 240 documents were selected through a search of the Scopus database. The complete linkage clustering method was used to draw out 16 clusters from 240 documents. Through MDS and pathfinder network analysis, knowledge networks of clusters have been produced. As a result. articles in the ASIST Proceedings relating to knowledge management, bibliometrics, information retrieval and digital libraries have been cited actively by other publications. The most frequent citation flow type of ASIST proceedings was citation from proceedings(ASIST) to reviews(ARIST), via journals, and the most popular subject areas related to documents were bibliometrics.

• Journal of Korea Society of Digital Industry and Information Management
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• v.12 no.2
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• pp.7-14
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• 2016

In this paper presents a low power algorithm using a feasible cluster generation method considered glitch. The proposed algorithm is a method for reducing power consumption of a given circuit. The algorithm consists of a feasible cluster generation process and glitches removal process. So that glitches are not generated for the node to which the switching operation occurs most frequently in order to reduce the power consumption is a method for generating a feasible cluster. A feasible cluster generation process consisted of a node value set, dividing the node, the node aligned with the feasible cluster generation. A feasible cluster generation procedure is produced from the highest number of nodes in the output. When exceeding the number of OR-terms of the inputs of the selected node CLB prevents the signal path is varied by the evenly divided. If there are nodes with the same number of outputs selected by the first highest number of nodes in the input produces a feasible cluster. Glitch removal process removes glitches through the path balancing in the same manner as [5]. Experimental results were compared with the proposed algorithm [5]. Number of blocks has been increased by 5%, the power consumption was reduced by 3%.

• Journal of the Korean Society for Library and Information Science
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• v.58 no.1
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• pp.395-415
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• 2024

In the development of a university library's collection, the concept of patron-driven acquisition refers to a collection strategy that addresses users' direct information needs. In this study, an analysis of ten years' worth of book requests by user types was conducted to understand the topic preferences for efficient collection devleopment in the university library. In collection development, identifying subject areas of users' requested books is necessary for librarians to identify key areas of collection development and establish balanced collection development policies. To identify the major subject areas for each user group, KDC (Korean Decimal Classification) subject classifications were used, and network analysis techniques were applied to investigate the relationships between book topics in detail. The analysis revealed that "social sciences" emerged as the major topic across all user groups. However, in the analysis of sub-topics, "medicine" and "psychology" were distinctively identified as the major subject areas for graduate students, setting them apart from other user groups. The result of the network analysis further indicated that undergraduate students showed unique topics such as civil service, job placement, and career, which were not observed as major topic clusters in other user groups. On the other hand, graduate students tended to concentrate on a few specialized subjects, forming distinct topic clusters in the analysis.

• Journal of KIISE:Databases
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• v.33 no.3
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• pp.342-352
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• 2006

Current studies on storing XML data are focused on either mapping XML data to existing RDBMS efficiently or developing a native XML storage. Some native XML storages store each XML node with parsed object form. Clustering, the physical arrangement of each object, can be an important factor to increase the performance with this storing method. In this paper, we propose re-clustering techniques that can store an XML document efficiently. Proposed clustering technique uses path similarities among data nodes, which can reduce page I/Os when returning query results. And proposed technique can process a path query only using small number of clusters as possible instead of using all clusters. This enables efficient processing of path query because we can reduce search space by skipping unnecessary data. Finally, we apply existing clustering techniques to store XML data and compare the performance with proposed technique. Our results show that the performance of XML storage can be improved by using a proper clustering technique.