• Title/Summary/Keyword: Index Structure

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An evaluation of stream naturalness for Close-to-nature stream restoration -In case of Suwon stream- (자연형 하천복원을 위한 하천자연도 평가 -수원천을 중심으로-)

  • Kim, Dong-Chan;Lee, Jung;Park, Il-Su
    • Journal of the Korean Institute of Landscape Architecture
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    • v.27 no.5
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    • pp.138-149
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    • 2000
  • The purpose of this study is to evaluate Suwon stream naturalness Index(S.N.I). and tofind out stats, problems and opportunities of the Suwon stream by assessment standard. Assessment standard is mainly based on physical structure of stream environment. the purpose evaluating sectors and elements are physical form and structure restoration of stream. To find out assessment standard of stream naturalness index, conceptual frame of assessment standard has been established, for which four sections, for example, longitudinal section, lateral section, stream bottom structure and water environment, have been selected. Overall stream naturalness index of the Suwon stream has been distributed at 3rd to 4th grade, and 3.3 of assessment index and mode were 3rd grade respectively. stream naturalness index of each section was as follows: Longitudinal section accounted for 3.7in average to be 4th grade, lateral section did 3.8 to be 4th grade, and water environment did 2.4 to be 2nd grade. Analysis of assessment outcome of stream naturalness index has checked status, problems and opportunities of corresponding stream. Assessment of stream naturalness index of the study provides useful information for restoration of close-to-nature stream, and furthermore has its meaning in checking problems and opportunities of Suwon stream.

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A Minimum Sequence Matching Scheme for Efficient XPath Processing

  • Seo, Dong-Min;Yeo, Myung-Ho;Kim, Myoung-Ho;Yoo, Jae-Soo
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.3 no.5
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    • pp.492-506
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    • 2009
  • Index structures that are based on sequence matching for XPath processing such as ViST, PRIX and LCS-TRIM have recently been proposed to reduce the search time of XML documents. However, ViST can cause a lot of unnecessary computation and I/O when processing structural joint queries because its numbering scheme is not optimized. PRIX and LCS-TRIM require much processing time for matching XML data trees and queries. In this paper, we propose a novel index structure that solves the problems of ViST and improves the performance of PRIX and LCS-TRIM. Our index structure provides the minimum sequence matching scheme to efficiently process structural queries. Finally, to verify the superiority of the proposed index structure with the minimum sequence matching scheme, we compare our index structure with ViST, PRIX and LCS-TRIM in terms of query processing of a single path or of a branching path including wild-cards ('*' and '//' ).

Design of Algorithm for Efficient Retrieve Pure Structure-Based Query Processing and Retrieve in Structured Document (구조적 문서의 효율적인 구조 질의 처리 및 검색을 위한 알고리즘의 설계)

  • 김현주
    • Journal of the Korea Computer Industry Society
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    • v.2 no.8
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    • pp.1089-1098
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    • 2001
  • Structure information contained in a structured document supports various access paths to document. In order to use structure information contained in a structured document, it is required to construct an index structural on document structures. Content indexing and structure indexing per document require high memory overhead. Therefore, processing of pure structure queries based on document structure like relationship between elements or element orders, low memory overhead for indexing are required. This paper suggests the GDIT(Global Document Instance Tree) data structure and indexing scheme about structure of document which supports low memory overhead for indexing and powerful types of user queries. The structure indexing scheme only index the lowest level element of document and does not effect number of document having retrieval element. Based on the index structure, we propose an query processing algorithm about pure structure, proof the indexing schemes keeps up indexing efficient in terms of space. The proposed index structure bases GDR concept and uses index technique based on GDIT.

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Phantom Protection Method for Multi-dimensional Index Structures

  • Lee, Seok-Jae;Song, Seok-Il;Yoo, Jae-Soo
    • International Journal of Contents
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    • v.3 no.2
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    • pp.6-17
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    • 2007
  • Emerging modem database applications require multi-dimensional index structures to provide high performance for data retrieval. In order for a multi-dimensional index structure to be integrated into a commercial database system, efficient techniques that provide transactional access to data through this index structure are necessary. The techniques must support all degrees of isolation offered by the database system. Especially degree 3 isolation, called "no phantom read," protects search ranges from concurrent insertions and the rollbacks of deletions. In this paper, we propose a new phantom protection method for multi-dimensional index structures that uses a multi-level grid technique. The proposed mechanism is independent of the type of the multi-dimensional index structure, i.e., it can be applied to all types of index structures such as tree-based, file-based, and hash-based index structures. In addition, it has a low development cost and achieves high concurrency with a low lock overhead. It is shown through various experiments that the proposed method outperforms existing phantom protection methods for multi-dimensional index structures.

An Efficient Index Structure for Bottom-Up Query Processing of XML Documents (XML 문서의 상향식 질의처리를 지원하는 효율적인 색인구조)

  • Seo Dong-Min;Kim Eun-Jae;Seong Dong-Ook;Yoo Jae-Soo;Cho Ki-Hyung
    • Journal of Internet Computing and Services
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    • v.7 no.4
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    • pp.101-113
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    • 2006
  • A path query is used in XML. Several index structures have been studied for processing the path query efficiently. In recent. the index schemes using suffix tree with structure join method were proposed. ViST is the most representative method among such methods. ViST processes the query using suffix tree and uses B+-tree to reduce the search time of the documents. However, it significantly degrades the search performance when processing the path query. The reason is that it regards the element that is not ancestor-descendant relation in the document as a descendent. In this paper, we propose an efficient index structure to solve the problem of ViST. The query processing method suitable to the index structure is also proposed. It is shown through various experiments that the proposed index structure outperforms the existing index structure in terms of the query processing time.

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A method to evaluate the risk-based robustness index in blast-influenced structures

  • Abdollahzadeh, Gholamreza;Faghihmaleki, Hadi
    • Earthquakes and Structures
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    • v.12 no.1
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    • pp.47-54
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    • 2017
  • Introduction of robustness index in the structure is done in three ways: deterministic robustness index, probabilistic robustness index, and risk-based robustness index. In past decades, there have been numerous researches to evaluate robustness index in both deterministic and probabilistic ways. In this research, by using a risk analysis, a risk-based robustness index has been defined for the structure. By creating scenarios in accordance with uncertainty parameters of critical and unexpected gas blast accident, a new method has been suggested for evaluating risk-based robustness index. Finally, a numerical example for the evaluation of risk-based robustness index of a four-storey reinforced concrete moment frame, designed and built based on Eurocode 8 code, has been presented with results showing a lower risk of robustness.

MPI: A Practical Index Scheme for XML Data in Object Databases

  • Song Ha-Joo
    • Journal of Korea Multimedia Society
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    • v.8 no.6
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    • pp.729-734
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    • 2005
  • In order to access XML data stored in object databases, an efficient index scheme is inevitable. There have been several index schemes that can be used to efficiently retrieve XML data stored In object databases, but they are all the single path indexes that support indexing along a single schema path. Henee, if a query contains an extended path which is denoted by wild character ('*'), a query processor has to examine multiple index objects, resulting in poor performance and inconsistent index management. In this paper, we propose MPI (Multi-Path Index) scheme as a new index scheme that provides the functionality of multiple path indexes more efficiently, while it uses only one index structure. The proposed scheme is easy to manage since it considers the extended path as a logically single schema path. It is also practical since it can be implemented by little modification of the B -tree index structure.

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An Index Structure for Efficient X-Path Processing on S-XML Data (S-XML 데이터의 효율적인 X-Path 처리를 위한 색인 구조)

  • Zhang, Gi;Jang, Yong-Il;Park, Soon-Young;Oh, Young-Hwan;Bae, Hae-Young
    • Proceedings of the Korea Information Processing Society Conference
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    • 2005.05a
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    • pp.51-54
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    • 2005
  • This paper proposes an index structure which is used to process X-Path on S-XML data. There are many previous index structures based on tree structure for X-Path processing. Because of general tree index's top-down query fashion, the unnecessary node traversal makes heavy access and decreases the query processing performance. And both of the two query types for X-Path called single-path query and branching query need to be supported in proposed index structure. This method uses a combination of path summary and the node indexing. First, it manages hashing on hierarchy elements which are presented in tag in S-XML. Second, array blocks named path summary array is created in each node of hashing to store the path information. The X-Path processing finds the tag element using hashing and checks array blocks in each node to determine the path of query's result. Based on this structure, it supports both single-path query and branching path query and improves the X-Path processing performance.

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The Automobile Distribution Industry's Trade Structure Analysis and Comparison between Japan and USA

  • Lee, Jae-Sung
    • Journal of Distribution Science
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    • v.12 no.7
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    • pp.37-44
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    • 2014
  • Purpose - This study reviews changes in the automobile export-import structure between Japan and USA through a trade related index, and focuses on analyzing comparative advantage based on time-series analysis of statistical data (2000, 2005, and 2012) by using the trade intensity index (TII), revealed comparative advantage index (RCA), and trade specialization index (TSI). Research design, data, and methodology - Japan and USA have mutually complementary economic phase characteristics. Therefore, this study aimed to understand each country's trade structure, to strengthen Japan-USA economic cooperation and aimed to examine trade drawbacks to analyze causes affecting trade and ways to improve it to facilitate its expansion. Results - These two economies have immense complementary potential and, further, significantly greater profits are assured from trade between them, as compared to any other integrated regional economic community. Conclusion - Economic cooperation between these two powers can provide opportunities for industry technology cooperation through partnerships against the backdrop of accelerating competition among industries, by identifying opportunities to secure stable resource suppliers and enlarge the export market.

Migration Policies of a Main Memory Index Structure for Moving Objects Databases

  • An Kyounghwan;Kim Kwangsoo
    • Proceedings of the KSRS Conference
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    • 2004.10a
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    • pp.673-676
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    • 2004
  • To manage and query moving objects efficiently in MMDBMS, a memory index structure should be used. The most popular index structure for storing trajectories of moving objects is 3DR-tree. The 3DR-tree also can be used for MMDBMS. However, the volume of data can exceed the capacity of physical memory since moving objects report their locations continuously. To accommodate new location reports, old trajectories should be migrated to disk or purged from memory. This paper focuses on migration policies of a main memory index structure. Migration policies consist of two steps: (i) node selection, (ii) node placement. The first step (node selection) selects nodes that should be migrated to disk. The criteria of selection are the performance of insertion or query. The second step (node placement) determines the order of nodes written to disk. This step can be thought as dynamic declustering policies.

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