• Journal of applied mathematics & informatics
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• v.25 no.1_2
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• pp.455-470
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• 2007

In phylogenetic tree construction the neighbor-joining algorithm is the most well known method which constructs a trivalent tree from a pairwise distance data measured by DNA sequences. The core part of the algorithm is its cherry picking criterion based on the tree structure of each quartet. We give a generalized version of the criterion based on the exact box model of quartets, known as the tight span of a metric. We also show by experiment why neighbor-joining and the quartet consistency count method give similar performance.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2006.11a
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• pp.589-598
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• 2006

The rectilinear Steiner tree problem is to find a minimum-length rectilinear interconnection of a set of terminals in the plane. It is well known that the solution to this problem will be the minimal spanning tree (MST) on some set Steiner points. A hybrid evolutionary algorithm is introduced based upon the Prim algorithm. The Prim algorithm for the fitness evaluation requires heavy calculation time. The fitness value of parents is inherited to their child and the fitness value of child is estimated by the inherited structure of tree. We introduce four alternative evolutionary algorithms, Experiment result shows that the calculation time is reduced to 25% without loosing the solution quality by using the fitness estimation.

• Proceedings of the Korean Information Science Society Conference
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• 2001.04b
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• pp.16-18
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• 2001

Despite extensive research on R-trees, most of the proposed schemes have not been integrated into existing DBMS due to the lack of protocol to provide consistency in concurrent environment. R-link tree is an acceptable data structure to deal with this issue., but still not enough. In this paper, we focus on a simplified predicate locking mechanism based on R-link tree for concurrency control and phantom protection. An in-memory operation control list (OCList) used to suspend some conflicting operations is designed here. The main features of this approach are (1) it can be implemented easily and do not need any extra information. (2) Only-one-lock is held when descending R-tree even when node split happens, while lock-coupling scheme is performed when ascending. No deadlocks are possible. (3) Searches and insertions are not unnecessarily restricted. (4) Insert and Delete phantom in R-link tree are avoid through beforehand predication.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.10A
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• pp.1004-1014
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• 2007

In sensor networks, it is crucial to reliably and energy-efficiently deliver sensed information from each source to a sink node. Specifically, in mobile sink (user) applications, due to the sink mobility, a stationary dissemination path may no longer be effective. The path will have to be continuously reconfigured according to the current location of the sink. Moreover, the dynamic optimal path from each source to the sink is required in order to reduce end-to-end delay and additional energy wastage. In this paper, an Adaptive Reversal Optimal path Tree (AROT) protocol is proposed. Information delivery from each source to a mobile sink can be easily achieved along the AROT without additional control overhead, because the AROT proactively performs adaptive sink mobility management. In addition, the dynamic path is optimal in terms of hop counts and the AROT can maintain a robust tree structure by quickly recovering the partitioned tree with minimum packet transmission. Finally, the simulation results demonstrate that the AROT is a considerably energy-efficient and robust protocol.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.43 no.3
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• pp.363-371
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• 1994

This thesis investigates an expert system(ES) to propose fault restoration plan by utilizing tree search strategies. In order to cope with an extensive amount of data and frequent breaker switching operations in distribution systems, the database of system configuration is constructed by using binary trees. This remarkably enhances the efficiency of search algorithm and makes the proposed ES easily adaptable to system changes due to switching operations. The rule-base is established to fully utilize the meris of tree-structured database. The inferring strategy is developed mainly based on the best-first search algorithm to increase computation efficiency. The proposed ES has been implemented to efficiently deal with large distribution systems by reducing computational burden remarkably compared with the conventional ES's.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.6 s.261
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• pp.651-658
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• 2007

A new tree-structured neural network classifier is proposed for the automatic real-time inspection of cold-rolled steel strip surface defects. The defects are classified into 3 groups such as area type, disk type, area & line type in the first stage of the tree-structured neural network. The defects are classified in more detail into 11 major defect types which are considered as serious defects in the second stage of neural network. The tree-structured neural network classifier consists of 4 different neural networks and optimum features are selected for each neural network classifier by using SFFS algorithm and correlation test. The developed classifier demonstrates very plausible result which is compatible with commercial products having high world-wide market shares.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.10a
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• pp.892-896
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• 2003

XML is used in various fields such as interface format for data swapping between application between several various system passing over thing to mark to web browser simply. Accordingly, a lot of studies about system that can manage effectively and search XML document with formation of information, reusability, disposal and durability, portability are proceeding. In this paper, explain about XQL and document structure processor and language processor of quality and make contents of XML document by tree structure, structure information presents method that find XML document tree structure information that is correct on question using XQL while do parsing. Through this, described for design and embodiment of efficient XML document search system that use XQL that compose structure information of document in tree structure and is proposed in language of quality after do parsing absorbing XML document that is scattered on web.

• Journal of KIISE:Computer Systems and Theory
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• v.31 no.9
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• pp.503-513
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• 2004

In large distributed systems, replications of data and service are needed to decrease communication cost, increase availability, and avoid single server bottleneck. Tree Quorum protocol is a representative replication protocol, which exploits a logical structure. Tree quorum protocol is one of the replication protocols allowing low read cost only in the best case, while the number of replicas exponentially increases as the level grows. In this paper, thus, we propose a new replication protocol, called symmetric tree protocol which efficiently solves the problem. The proposed symmetric tree protocol also requires much smaller read cost than previous protocols. We conduct cost and availability analysis of the protocols, and the proposed protocol displays comparable read availability to the tree protocol using much smaller number of nodes. Also, the symmetric tree protocol has much smaller response time than the logarithmic protocol.

• The KIPS Transactions:PartB
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• v.12B no.4 s.100
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• pp.487-498
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• 2005

Recently, It has focused on decision tree algorithm that can handle large dataset. However, because most of these algorithms for large datasets process data in a batch mode, if new data is added, they have to rebuild the tree from scratch. h more efficient approach to reducing the cost problem of rebuilding is an approach that builds a tree incrementally. Representative algorithms for incremental tree construction methods are BOAT and ITI and most of these algorithms use a local discretization method to handle the numeric data type. However, because a discretization requires sorted numeric data in situation of processing large data sets, a global discretization method that sorts all data only once is more suitable than a local discretization method that sorts in every node. This paper proposes an incremental tree construction method that efficiently rebuilds a tree using a global discretization method to handle the numeric data type. When new data is added, new categories influenced by the data should be recreated, and then the tree structure should be changed in accordance with category changes. This paper proposes a method that extracts sample points and performs discretiration from these sample points to recreate categories efficiently and uses confidence intervals and a tree restructuring method to adjust tree structure to category changes. In this study, an experiment using people database was made to compare the proposed method with the existing one that uses a local discretization.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.5
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• pp.471-479
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• 2009

In this paper, we proposed an improved ray tracing method with an amelioration of visible tree structure, a visible face determination method, and non-uniform random test point method. In a proposed visible tree structure, it reduces tree nodes by means of merging similar nodes. In a visible face determination method, it shows that a ray hit test with a packet ray method can reduce a test time. A ray tracing method involving with a packet ray hit test method can improve a tree construction time up to 3.3 times than a ray tracing method with a single ray hit test method. Furthermore, by seeding a non-uniform and random test point on a face, tree construction time is improved up to 1.11 times. Received powers from the proposed ray tracing results and measured results have good agreement with 1.9 dB RMS error.