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An Optimized Address Lookup Method in the Multi-way Search Tree (멀티웨이 트리에서의 최적화된 어드레스 룩업 방법)

  • 이강복;이상연;이형섭
    • Proceedings of the IEEK Conference
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    • pp.261-264
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    • 2001
  • This paper relates to a node structure of a multiway search tree and a search method using the node structure and, more particularly, to a search method for accelerating its search speed by reducing the depth of each small tree in a multi-way search tree. The proposed idea can increase the number of keys capable of being recorded on a cache line by using one pointer at a node of the multi-way search tree so that the number of branches in a network address search is also increased and thus the tree depth is reduced. As a result, this idea can accelerate the search speed and the speed of the forwarding engine and accomplish a further speed-up by decreasing required memories and thus increasing a memory rate.

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Restoration of Distribution System with Distributed Energy Resources using Level-based Candidate Search

  • Kim, Dong-Eok;Cho, Namhun
    • Journal of Electrical Engineering and Technology
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    • v.13 no.2
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    • pp.637-647
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    • 2018
  • In this paper, we propose a method to search candidates of network reconfiguration to restore distribution system with distributed energy resources using a level-based tree search algorithm. First, we introduce a method of expressing distribution network with distributed energy resources for fault restoration, and to represent the distribution network into a simplified graph. Second, we explain the tree search algorithm, and introduce a method of performing the tree search on the basis of search levels, which we call a level-based tree search in this paper. Then, we propose a candidate search method for fault restoration, and explain it using an example. Finally, we verify the proposed method using computer simulations.

An Improvement Video Search Method for VP-Tree by using a Trigonometric Inequality

  • Lee, Samuel Sangkon;Shishibori, Masami;Han, Chia Y.
    • Journal of Information Processing Systems
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    • v.9 no.2
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    • pp.315-332
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    • 2013
  • This paper presents an approach for improving the use of VP-tree in video indexing and searching. A vantage-point tree or VP-tree is one of the metric space-based indexing methods used in multimedia database searches and data retrieval. Instead of relying on the Euclidean distance as a measure of search space, the proposed approach focuses on the trigonometric inequality for compressing the search range, which thus, improves the search performance. A test result of using 10,000 video files shows that this method reduced the search time by 5-12%, as compared to the existing method that uses the AESA algorithm.

Implementation of Connected-Digit Recognition System Using Tree Structured Lexicon Model (트리 구조 어휘 사전을 이용한 연결 숫자음 인식 시스템의 구현)

  • Yun Young-Sun;Chae Yi-Geun
    • MALSORI
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    • no.50
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    • pp.123-137
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    • 2004
  • In this paper, we consider the implementation of connected digit recognition system using tree structured lexicon model. To implement efficiently the fixed or variable length digit recognition system, finite state network (FSN) is required. We merge the word network algorithm that implements the FSN with lexical tree search algorithm that is used for general speech recognition system for fast search and large vocabulary systems. To find the efficient modeling of digit recognition system, we investigate some performance changes when the lexical tree search is applied.

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Selection of the Optimal Decision Tree Model Using Grid Search Method : Focusing on the Analysis of the Factors Affecting Job Satisfaction of Workplace Reserve Force Commanders (격자탐색법을 이용한 의사결정나무 분석 최적 모형 선택 : 직장예비군 지휘관의 직장만족도에 대한 영향 요인 분석을 중심으로)

  • Jeong, Chulwoo;Jeong, Won Young;Shin, David
    • Journal of the Korean Operations Research and Management Science Society
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    • v.40 no.2
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    • pp.19-29
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    • 2015
  • The purpose of this study is to suggest the grid search method for selecting an optimal decision tree model. It chooses optimal values for the maximum depth of tree and the minimum number of observations that must exist in a node in order for a split to be attempted. Therefore, the grid search method guarantees building a decision tree model that shows more precise and stable classifying performance. Through empirical analysis using data of job satisfaction of workplace reserve force commanders, we show that the grid search method helps us generate an optimal decision tree model that gives us hints for the improvement direction of labor conditions of Korean workplace reserve force commanders.

Sparse Signal Recovery via Tree Search Matching Pursuit

  • Lee, Jaeseok;Choi, Jun Won;Shim, Byonghyo
    • Journal of Communications and Networks
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    • v.18 no.5
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    • pp.699-712
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    • 2016
  • Recently, greedy algorithm has received much attention as a cost-effective means to reconstruct the sparse signals from compressed measurements. Much of previous work has focused on the investigation of a single candidate to identify the support (index set of nonzero elements) of the sparse signals. Well-known drawback of the greedy approach is that the chosen candidate is often not the optimal solution due to the myopic decision in each iteration. In this paper, we propose a tree search based sparse signal recovery algorithm referred to as the tree search matching pursuit (TSMP). Two key ingredients of the proposed TSMP algorithm to control the computational complexity are the pre-selection to put a restriction on columns of the sensing matrix to be investigated and the tree pruning to eliminate unpromising paths from the search tree. In numerical simulations of Internet of Things (IoT) environments, it is shown that TSMP outperforms conventional schemes by a large margin.

IP Prefix Update of Routing Protocol in the Multi-way Search Tree (멀티웨이 트리에서의 IP Prefix 업데이트 방안)

  • 이상연;이강복;이형섭
    • Proceedings of the IEEK Conference
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    • pp.269-272
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    • 2001
  • Since Multi-way Search Tree reduces the number of the memory access by increasing the branch factor, it is considered a method to archive the high-speed IP address lookup. Using the combination of initial 16 bit may and Multi-way Search Tree, it also reduces the search time of If address lookup. Multi-way Search Tree consists of K keys and K+1 key pointers. This paper shows how the E update of Multi-way Search Tree which consists of the one pointer within a node can be performed. Using the one pointer within a node, it increases the number of keys within a node and reduces the search time of IP lookup. We also describes IP updating methods such as modification, Insertion and Deletion of address entries. Our update scheme performs better than the method which rebuilds the entire IP routing table when IP update processes.

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MR-Tree: A Mapping-based R-Tree for Efficient Spatial Searching (Mr-Tree: 효율적인 공간 검색을 위한 매핑 기반 R-Tree)

  • Kang, Hong-Koo;Shin, In-Su;Kim, Joung-Joon;Han, Ki-Joon
    • Spatial Information Research
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    • v.18 no.4
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    • pp.109-120
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    • 2010
  • Recently, due to rapid increasement of spatial data collected from various geosensors in u-GIS environments, the importance of spatial index for efficient search of large spatial data is rising gradually. Especially, researches based R-Tree to improve search performance of spatial data have been actively performed. These previous researches focus on reducing overlaps between nodes or the height of the R -Tree. However, these can not solve an unnecessary node access problem efficiently occurred in tree traversal. In this paper, we propose a MR-Tree(Mapping-based R-Tree) to solve this problem and to support efficient search of large spatial data. The MR-Tree can improve search performance by using a mapping tree for direct access to leaf nodes of the R-Tree without tree traversal. The mapping tree is composed with MBRs and pointers of R-Tree leaf nodes associating each partition which is made by splitting data area repeatedly along dimensions. Especially, the MR-Tree can be adopted in various variations of the R-Tree easily without a modification of the R-Tree structure. In addition, because the mapping tree is constructed in main memory, search time can be greatly reduced. Finally, we proved superiority of MR-Tree performance through experiments.

Detection and Location of Open Circuit Fault by Space Search (Space Search에 의한 회로의 단선 결함을 발견 및 위치 검색법)

  • Han, Kyong-Ho;Kang, Sang-Won;Lee, In-Sung
    • The Journal of the Acoustical Society of Korea
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    • v.14 no.2E
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    • pp.43-49
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    • 1995
  • In this paper a space search technique is used to detect and locate the faults of the circuit interconnections. The circuit interconnections are represented by the tree structure and the tree space is searched to detect and locate the open faults of the circuit interconnections. The breadth search is used to detect the open faults and reduce the space size. The depth search is used to locate the open faults.

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Sparse Signal Recovery Using A Tree Search (트리검색 기법을 이용한 희소신호 복원기법)

  • Lee, Jaeseok;Shim, Byonghyo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.39A no.12
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    • pp.756-763
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    • 2014
  • In this paper, we introduce a new sparse signal recovery algorithm referred to as the matching pursuit with greedy tree search (GTMP). The tree search in our proposed method is implemented to minimize the cost function to improve the recovery performance of sparse signals. In addition, a pruning strategy is employed to each node of the tree for efficient implementation. In our performance guarantee analysis, we provide the condition that ensures the exact identification of the nonzero locations. Through empirical simulations, we show that GTMP is effective for sparse signal reconstruction and outperforms conventional sparse recovery algorithms.