• The Journal of the Acoustical Society of Korea
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• v.22 no.4
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• pp.323-328
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• 2003

This study describes an energy contour generation method for Korean n systems. We propose a vector-regression tree, which is a vector version of a scalar regression tree. A vector-regression tree predicts a response vector for an unknown feature vector. In our study, the tree yields a vector containing ten sampled energy values for each phone. After collecting 500 sentences and its corresponding speech corpus, we trained trees on 300 sentences and tested them on 200 sentences. We construct a bagged tree and a born again one to improve the performance of contour prediction. In the experiment, we got a 0.803 correlation coefficient for the observed and predicted energy values.

• Journal of IKEEE
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• v.22 no.3
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• pp.850-853
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• 2018

In this paper, we propose a decoding method using a balanced binary tree and a canonical Huffman tree for efficient decoding of Huffman codes. The balanced binary tree scheme reduces the number of searches by lowering the height of the tree and binary search. However, constructing a tree based on the value of the code instead of frequency of symbol is a drawback of the balanced binary tree. In order to overcome these drawbacks, a balanced binary tree is reconstructed according to the occurrence probability of symbols at each level of the tree and binary search is performed for each level. We minimize the number of searches using a canonical Huffman tree to find level of code to avoid searching sequentially from the top level to bottom level.

• The Transactions of the Korea Information Processing Society
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• v.6 no.8
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• pp.2253-2261
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• 1999

ACK generates optimized code using the string pattern matching technique in pattern table generator and peephole optimizer. But string pattern matching method is not effective due to the many comparative actions in pattern selection. We designed and implemented the EM intermediate code optimizer using tree pattern matching algorithm composed of EM tree generator, optimization pattern table generator and tree pattern matcher. Tree pattern matching algorithm practices the pattern matching that centering around root node with refer to the pattern table, with traversing the EM tree by top-down method. As a result, compare to ACK string pattern matching methods, we found that the optimized code effected to pattern selection time, and contributed to improved the pattern selection time by about 10.8%.

• The KIPS Transactions:PartA
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• v.8A no.3
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• pp.209-216
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• 2001

The effective way to apply incremental attribute grammar to a complex language process is the use of optimized algorithm. In optimized algorithm for incremental attribute grammar, the new input attribute tree should be exactly compared with the previous input attribute tree, in order to determine which subtrees from the old should be used in constructing the new one. In this paper the new optimized algorithm was reconstructed by analyzing the algorithm suggested by Carle and Pollock, and a generation process of new attribute tree d’copy was added. Through the performance evaluation for the suggested matching algorithm, the run time is approximately improved by 19.5%, compared to the result of existing algorithm.

• Journal of the Korea Computer Industry Society
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• v.3 no.2
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• pp.235-242
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• 2002

To minimize restructuring cost of a tree, experiments were conducted to collect quantitative information of searching efficiencies varying degrees of imbalance in a binary search tree. Degrees of tree imbalance were measured by a balance factor, an absolute value of height difference of left subtree and right subtree in a binary search tree. The average number of comparisons increased (p＜0.01), and searching efficiency of O(n) was more appropriate rather than O(logn), as degrees of imbalance in a binary search tree deteriorated. However, there were no significant differences of searching efficiencies in height balanced trees and trees with subtrees to have height 3 less than the other (p＞0.05). Therefore, the findings would be applicable to maintain searching efficiency of a software with a binary search tree.

• Journal of Internet Computing and Services
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• v.2 no.3
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• pp.71-79
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• 2001

In Incremental attribute evaluation algorithm, a new input attribute is exact1y compared with a previous input attribute tree, and then determine which subtrees from the old should be used in constructing the new one. In this paper incremental attribute evaluation algorithm was used to make incremental evlauation of hierarchical attribute grammar more efficient1y, and reconstructing the incremental attribute evaluation algorithm by analyzing that of Carle and Pollock, finally the incremental attribute evaluation algorithm for optimalized attribute tree d' copy was constructed by applying element of attribute !ree dcopy to a new attribute tree d' copy. Also proving that how the reused nod and type of defined parameter in input program carried out the incremental attribute evaluation by using that algorithm.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07b
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• pp.49-51
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• 2005

시간의 흐름에 따라 그 위치가 빈번히 변화하는 이동 객체의 특성으로 인해 실시간으로 증가하는 이동객체의 연산 정보를 효과적으로 관리할 수 있는 효율적인 연산 기법이 요구된다. 따라서 본 논문에서는 이동 객체의 시공간 연산을 위해 기존에 제안되었던 HR 트리의 성능을 개선시킬 수 있는 확장된 HR-트리(Extended HR-Tree : EHR-Tree)를 제안한다. 기존의 HR 트리는 삽입, 삭제, 갱신과 같은 연산이 빈번한 경우에 단말 노드 및 비단말 노드를 새로 생성해야 함으로 인하여 성능이 떨어지고, 공간의 낭비가 있게 된다. 이 문제를 해결하기 위해 본 논문에서 제안하는 EHR-트리는 연산이 발생할 때마다 새로운 HR-트리를 생성하는 것이 아니라 시간 구간을 두어서 새로 발생한 연산이 같은 시간 구간에 있을 경우 그 단위시간에 생성된 HR-트리에 그대로 삽입, 삭제, 갱신과 같은 연산을 수행하게 된다. 따라서 기존 HR-트리에서 단말 노드 및 비단말 노드를 새로 생성해야함으로 발생되던 많은 저장 공간 요구를 감소시킴으로, 즉 전체 연산 크기를 작게 하여 디스크 I/O수를 감소시킴으로써, 시공간 질의의 처리 속도를 향상시켜 효율적인 질의가 가능하도록 한다.

• Journal of Korea Society of Industrial Information Systems
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• v.15 no.1
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• pp.37-46
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• 2010

A Suffix Tree is an efficient data structure that exposes the internal structure of a string and allows efficient solutions to a wide range of complex string problems, in particular, in the area of computational biology. However, as the biological information explodes, it is impossible to construct the suffix trees in main memory. We should find an efficient technique to construct the trees in a secondary storage. In this paper, we present a method for constructing a suffix tree in a disk for large set of DNA strings using new index scheme. We also show a typical application example with a suffix tree in the disk.

• Journal of KIISE:Information Networking
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• v.34 no.5
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• pp.316-327
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• 2007

RFID (Radio Frequency Identification) is one of the most promising air interface technologies in the future for object identification using radio wave. If there are multiple tags within the range of the RFID tag reader, all tags send their tag identifications to the reader at the same time in response to the reader's query. This causes collisions on the reader and no tag is identified. A multi-tag identification problem is a core issue in the RFID. It can be solved by anti-collision algorithm such as slot based ALHOA algorithms and tree based algorithms. This paper, proposes a collision tree based anti-collision algorithm using collision tree in RFID system. It is a memory-less algorithm and is an efficient RFID anti-collision mechanism. The collision tree is a mechanism that can solve multi-tag identification problem. It is created in the process of querying and responding between the reader and tags. If the reader broadcasts K bits of prefix to multiple tags, all tags with the identifications matching the prefix transmit the reader the identifications consisted of k+1 bit to last. According to the simulation result, a proposed collision tree based anti-collision algorithm shows a better performance compared to tree working algorithm and query tree algorithm.

• Journal of KIISE:Information Networking
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• v.28 no.4
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• pp.611-620
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• 2001

To meet the requirements of reliable service for various applications, a Reliable Multicast Transport Protocol should be implemented over IP Multicast where currently best-effort service is provided. Among the current researches, hierarchical tree-based mechanism has been proposed and actively studied. This mechanism is known to provide high scalability as well as reliability, but needs an additional tree configuring mechanism for building an efficient logical tree in transport layer. Bottom-up approach has been used for creating such a tree. This method has benefits from parallel tree construction for receivers, while it has some drawbacks such that it does not guarantee a loop-free tree and brings heavy message overhead during tree creation process. Therefore, this paper proposes a top-down based mechanism for constructing a control tree, which can guarantee loop-freeness by step-wise mannered tree building. From experimental simulations, it shows that the proposed mechanism has less message overhead. It is recommended that the bottom-up and the proposed top-down will be selectively used in real networks, according to the requirements of the concerned multicast applications.