• Convergence Security Journal
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• v.7 no.4
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• pp.29-34
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• 2007

This paper proposes RCB(Reduced Compact Binary) trie to correct faults of CB(Compact Binary) trie. First, in the case of CB trie, a compact structure was tried for the first time, but as the amount of data was increasing, that of inputted data gained and much difficulty was experienced in insertion due to the dummy nods used in balancing trees. On the other hand, if the HCB trie realized hierarchically, given certain depth to prevent the map from increasing on the right, reached the depth, the method for making new trees and connecting to them was used. Eventually, fast progress could be made in the inputting and searching speed, but this had a disadvantage of the storage space becoming bigger because of the use of dummy nods like CB trie and of many tree links. In the case of RCB trie in this thesis, a capacity is increased by about 60% by completely cutting down dummy nods.

• Proceedings of the IEEK Conference
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• 2001.06d
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• pp.131-134
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• 2001

본 논문에서는 효율적인 허프만 디코딩을 수행할 수 있도록 하기 위하여 Bit-wise comparison 방법을 제시하였다. 이 방법은 허프만 코딩 원리인 이진트리 구성에 기초하여 허프만 테이블을 재구성 함으로서 디코딩 사간의 단축 및 알고리즘의 간소화를 가져오도록 하였고, 이를 토대로 MPEG-2 AAC 디코더의 허프만 디코딩 부분에 적용함으로써 성능검증을 수행하였다.

• Proceedings of the Korean Information Science Society Conference
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• 2002.04b
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• pp.514-516
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• 2002

3D 가상공간 사용자의 몰입감과 임장감에 결정적인 영창을 미치는 상호작용기법은 공간 네비게이션과 객체조작기법으로 나눌 수 있다. 그중 정교한 객체조작이 요구되는 특정분야에서는 보다 효과적인 객체조작기법이 절실히 요구된다. 본 논문에서는 객체를 구성하는 장면 그래프 구조를 사용자의 선택에 따라 내부적으로 분할하여 재구성한 선택트리의 순회를 통해 객체의 세부 단위요소를 선택하고 이를 조작하며 선택을 해제를 할 수 있는 일련의 기법을 제안한다. 제안된 기법은 정교한 객체의 조작을 필요로 하는 분야의 3D 사용자 인터페이스 구축에 효과적으로 적용될 수 있을 것이다.

• Proceedings of the Korea Multimedia Society Conference
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• 2004.05a
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• pp.579-582
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• 2004

본 논문에서는 PDA 장치를 위한 MPEG-4 콘텐츠를 저작하기 위한 스케일링 방법을 제안한다. 제안하는 스케일링 방법은 저작시 MPEC-4 콘텐츠의 씬 트리를 이용하여 PDA 장치에서 재생할 수 있도록 mp4 파일를 재구성하는 방법이다. 이 방법은 PDA 장치의 작은 인터페이스에서 재생을 효율적으로 할 수 있도륵 객체의 크기를 축소하고, 모든 객체를 아이콘의 기하 객체로 기술하여 초기 로딩 시간을 감소시킨다.

• Journal of the Korea Society of Computer and Information
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• v.15 no.3
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• pp.81-89
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• 2010

The research on peer-to-peer streaming schemes has largely focused on tree-push and mesh-pull structures. However, the tree-push structure has a defect that the tree restructuring time is long, and the mesh-pull structure has long startup delay and lag time from source servers. In this paper, we propose a new peer-to-peer live streaming scheme based on a push-mesh structure that takes advantages of tree-push and mesh-pull structure simultaneously. This structure basically provides the mesh-pull mechanism for data transmission and utilizes peers with high network upload capacity. It also supports the push mechanism along with paths from a source server, super peers, and selected general peers. By NS-2 simulation experiments, we finally show that our proposed scheme can achieve shorter startup delay than the mesh-pull structure, similar lag time to tree-push structure and best playback continuity among the three schemes.

• Journal of The Korean Association of Information Education
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• v.26 no.1
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• pp.65-73
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• 2022

In this study, by using Entry text model learning, educational contents for artificial intelligence education of elementary school students are developed and applied to actual classes. Based on the elementary and secondary artificial intelligence content table, the achievement standards of practical software education and artificial intelligence education will be reconstructed.. Among text, images, and sounds capable of machine learning, "production of emotion recognition programs using text model learning" will be selected as the educational content, which can be easily understood while reducing data preparation time for elementary school students. Entry artificial intelligence is selected as an education platform to develop artificial intelligence education contents that create emotion recognition programs using text model learning and apply them to actual elementary school classes. Based on the contents of this study, As a result of class application, students showed positive responses and interest in the entry AI class. it is suggested that quantitative research on the effectiveness of classes for elementary school students is necessary as a follow-up study.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.10
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• pp.1537-1544
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• 2022

When designing chip, it considers design specification, timing problem, and clock synchronization on place & route (P&R) process. P&R process is complicated because of considering various factors. Chip uses clock tree synthesis (CTS) to reduce clock path delay. The purpose of this study is to examine shallow-CTS algorithm for checking clock tree synthesizable. Using open source Parser-Verilog, register transfer level (RTL) synthesizable Verilog file is parsed and it uses Pre-CTS and Post-CTS process that is included shallow-CTS. Based on longest clock path in the Pre-CTS and Post-CTS stages, the standard deviation before and after buffer insertion is compared and analyzed for the accuracy of CTS. In this paper, It is expected that the cost and time problem could be reduced by providing a pre-clock tree synthesis verification method at the RTL level without confirming the CTS result using the time-consuming licensed EDA tool.

• The KIPS Transactions:PartC
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• v.10C no.3
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• pp.377-386
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• 2003

This study suggested a technique to maintain an efficient core-based multicast tree using weighted clustering factors in mobile Ad-hoc networks. The biggest problem with the core-based multicast tree routing is to decide the position of core node. The distance of data transmission varies depending on the position of core node. The overhead's effect on the entire network is great according to the recomposition of the multicast tree due to the movement of core node, clustering is used. A core node from cluster head nodes on the multicast tree within core area whose weighted factor is the least is chosen as the head core node. Way that compose multicast tree by weighted clustering factors thus and propose keeping could know that transmission distance and control overhead according to position andmobility of core node improve than existent multicast way, and when select core node, mobility is less, and is near in center of network multicast tree could verification by simulation stabilizing that transmission distance is short.

• The KIPS Transactions:PartD
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• v.15D no.6
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• pp.755-766
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• 2008

Recently, NAND flash memory is becoming into the spotlight as a next-generation storage device because of its small size, fast speed, low power consumption, and etc. compared to the hard disk. However, due to the distinct characteristics such as erase-before-write architecture, asymmetric operation speed and unit, disk-based systems and applications may result in severe performance degradation when directly implementing them on NAND flash memory. Especially when a B-tree is implemented on NAND flash memory, intensive overwrite operations may be caused by record inserting, deleting, and reorganizing. These may result in severe performance degradation. Although ${\mu}$-tree has been proposed in order to overcome this problem, it suffers from frequent node split and rapid increment of its height. In this paper, we propose Log-Structured B-Tree(LSB-Tree) where the corresponding log node to a leaf node is allocated for update operation and then the modified data in the log node is stored at only one write operation. LSB-tree reduces additional write operations by deferring the change of parent nodes. Also, it reduces the write operation by switching a log node to a new leaf node when inserting the data sequentially by the key order. Finally, we show that LSB-tree yields a better performance on NAND flash memory by comparing it to ${\mu}$-tree through various experiments.

• Journal of Korea Spatial Information System Society
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• v.6 no.2 s.12
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• pp.3-13
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• 2004

The TPR-tree exploits bounding rectangles based on the function of time in order to index moving objects. As time passes on, each edge of a BR expands with the fastest velocity vector. Since the expansion of the BR results in a serious overlaps between neighboring nodes, the performance of range query is getting worse. In this paper, we propose schemes to reorganize bounding rectangles of nodes. When inserting a moving object, we exploit a forced merging scheme to merge two overlapped nodes and re-split it. When deleting a moving object, we used forced reinsertion schemes to reinsert other objects of a node into a tree. The forced reinsertion schemes are classified into a deleted node reinsertion scheme and an overlapped nodes reinsertion scheme. The overlapped nodes reinsertion scheme outperforms the forced merging scheme and the deleted node reinsertion scheme in all experiments.